This guidance document provides recommended values ​​for the dimensional deviations of gear blanks, center distances and axis parallelism. The values ​​listed in this guidance document should not be considered as strict quality criteria, but as a guide for steel or iron gears when negotiating mutual agreements. GB/Z 18620.3-2002 Specification for the inspection of cylindrical gears Part 3: Gear blanks, shaft center distances and axis parallelism GB/Z18620.3-2002 Standard download decompression password: www.bzxz.net

ICS_21.200
National Standardization Guiding Technical Documents of the People's Republic of China GB/Z18620.3—2002
idt ISO/TR 10064-3:1996
Cylindrical gears
Inspection implementation code
Part 3:
|Cylindrical gears-Code of inspection practice--Part 3: Recommendations relative to gear blanks, shaft centre distance and parallelism of axes2002-01-10 Issued
People's Republic of China
General Administration of Quality Supervision, Inspection and Quarantine
2002-08-01 Implementation
GB/Z18620.3—2002
ISO Foreword
ISO Introduction
1 Scope
2 Referenced standards
3 Symbols and definitions
4 Accuracy of gear bearings
5 Center distance and parallelism of axes
Appendix A (Suggestive appendix) Bibliography
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GB/Z18620.3—2002
This guiding technical document is equivalent to ISO/TR10064-3:1996 "Cylindrical gear inspection implementation specification Part 3: Recommended document on gear bearings, shaft center distance and axis parallelism". The technical content is exactly the same as ISO/TR10064-3. In the process of revising GB/T10095-1988, it was agreed that the description and opinions on gear inspection methods should be raised to the modern technical level. Due to the increase in content and other considerations, it was decided to publish the relevant parts as a separate volume of guiding technical documents, so that together with Part 1 and Part 2 of GB/T10095, a system of standards and guiding technical documents (listed in Chapter 2 and Appendix A) is formed.
GB/Z18620, under the general title "Specification for the Implementation of Cylindrical Gear Inspection", includes the following parts: Part 1: Inspection of tooth surfaces on the same side of gear teeth; Part 2: Inspection of radial combined deviation, radial runout, tooth thickness and backlash; Part 3: Gear wear, shaft center distance and axis parallelism; Part 4: Inspection of surface structure and gear tooth contact spots. This guiding technical document is for reference only. Suggestions and opinions on the guiding technical document can be reflected to the standardization administrative department of the State Council.
Appendix A of this guidance technical document is a prompt appendix. This guidance technical document is proposed by China Machinery Industry Federation. This guidance technical document is under the jurisdiction of the National Gear Standardization Technical Committee. This guidance technical document was drafted by Zhengzhou Machinery Research Institute. The main drafters of this guidance technical document are: Zhang Min'an, Zhang Yuanguo, Li Shizhong, Yang Xingyuan, Wang Qi, Xu Hongji. GB/Z18620.3—2002
ISO Foreword
ISO (International Organization for Standardization) is a worldwide federation composed of national standardization groups (ISO member groups). The work of formulating international standards is usually completed by ISO's technical committees. If each member group is interested in a standard project established by a technical committee, it has the right to participate in the work of the committee. International organizations (official or unofficial) that maintain contact with ISO may also participate in the relevant work. In terms of electrotechnical standardization, ISO maintains a close cooperative relationship with the International Electrotechnical Commission (IEC). The main task of the technical committee is to develop international standards, but in special circumstances, the technical committee may recommend the publication of one of the following types of technical reports (TR):
- Type 1
! When repeated efforts have not yet obtained the support required for the publication of an international standard; when the project is still in technical development, or for various reasons, it is only possible in the future rather than at present. Type 2
Agree to become an international standard;
- Type 3 When a technical committee collects information that is different from the international standards that are normally published (for example, to adapt to the current state of the art).
Type 1 and Type 2 technical reports should be reviewed within three years after publication to determine whether they can be transformed into international standards; Type 3 technical reports do not necessarily have to be reviewed and are used until the information provided is no longer considered useful or valid. ISO/TR10064-3 is a technical report belonging to Type 3, which was developed by ISO/TC60 Gear Technical Committee. ISO 10064, under the general title "Specification for the inspection of cylindrical gears", includes the following parts: - Part 1: Inspection of tooth flanks on the same side of the gear teeth; - Part 2: Inspection of radial combined deviation, radial runout, tooth thickness and backlash; - Part 3: Recommended documents on gear tooth, shaft center distance and axis parallelism; - Part 4: Recommended documents on surface structure and tooth contact spot inspection. Annex A to this part of ISO/TR 10064 is a bibliographic list. ISO Introduction
In the process of revising ISO 1328:1975, it was agreed that It is intended that the description and values ​​of the inspection of gear blanks, shaft centre distance and parallelism of the axes be published as a third type of technical report in separate volumes. A series of documents listed in Chapter 2 (referenced norms) and Appendix A (bibliography) have been prepared together with this technical report to replace IS01328:1975. HiiKAoNKAca-
1 Scope
National Standardization Guiding Technical Documents of the People's Republic of China Cylindrical gears-Code of inspection practice-Part 3: Recommendations relative to gear blanks, shaft centre distance and parallelism of axes Cylindrical gears-Code of inspection practice-Part 3: Recommendations relative to gear blanks, shaft centre distance and parallelism of axes axesGB/Z18620.3—2002
idtIS0/TR10064-3:1996
This guidance technical document provides recommended values ​​for gear shaft, dimensional deviation of center distance and axis parallelism. The values ​​listed in this guidance technical document should not be considered as strict quality criteria, but as a guide for steel or iron gears when negotiating mutual agreements.
2 Cited standards
The provisions contained in the following standards constitute the provisions of this guidance technical document through reference in this guidance technical document. When this guidance technical document was published, the versions shown were valid. All standards will be revised, and parties using this guidance technical document should explore the possibility of using the latest versions of the following standards. GB/T1356—2001 Standard basic rack tooth profile for cylindrical gears for general machinery and heavy machinery (idtISO53:1998) GB/T1357—1 987 Involute cylindrical gear module (neqISO54:1977) GB/T1800.1-1997 Limits and fit basis Part 1: Vocabulary (neqISO286-1:1988) GB/T10095.1-2001 Involute cylindrical gear accuracy Part 1: Definition and allowable values ​​of tooth surface deviation on the same side of the gear (idtISO1328-1:1997)
GB/T10095.2-2001|| tt||3 Symbols and definitions
3.1 Symbols
Precision of involute cylindrical gears - Part 2: Definitions and permissible values ​​of combined radial deviation and radial runout (idtISO1328-2:1997)
The deviation symbols used for measuring individual elements are composed of lowercase letters (such as f) plus the corresponding subscripts; while the symbols used to represent the "total" deviation of the combination of several individual element deviations are composed of uppercase letters (such as F) plus the corresponding subscripts. a
Center distance
Diameter of reference surface
Mounting surface diameter
Axis parallelism deviation in axis plane
Axis parallelism deviation on vertical plane
Total helix deviation
Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on January 10, 2002 mm
Implemented on August 1, 2002
3.2 Definitions
Total cumulative deviation of tooth pitch
Large bearing span
Number of links in tolerance chain
This guidance technical document adopts the following definitions. 3.2.1 Working mounting surface
The surface used to mount the gear.
3.2.2 Working axis
GB/Z18620.3--2002
refers to the axis about which the gear rotates during operation and is determined by the center of the working mounting surface. The working axis is meaningful only when the entire gear assembly is considered.
3.2.3 Datum surface
is the surface used to determine the datum axis.
3.2.4 Datum axis
is determined by the center of the datum surface. The gear is determined by this axis to determine the details of the gear, especially the tolerances of the pitch, tooth profile and helix. 3.2.5 Manufacturing mounting surface
is the surface used to mount the gear during gear manufacturing or testing. 4 Gear tooth accuracy
This chapter discusses the selection of the datum axis, the datum surface used to determine it, and other related datum surfaces and gives sufficient and clear provisions. The values ​​of the parameters related to the gear tooth accuracy (tooth profile deviation, adjacent pitch deviation, etc.) are meaningful only when the specific rotation axis is specified. If the axis about which the gear rotates during measurement changes, the measured values ​​of these parameters will also change. Therefore, the reference axis for the gear tooth tolerance must be clearly indicated on the gear drawing. In fact, the geometric shape of all the entire gear is based on it. The dimensional deviation of the gear and the gear housing has a great influence on the contact conditions and operating conditions of the gear pair. Since it is much more economical to maintain a tight tolerance when machining the gear and housing than to machine high-precision gear teeth, the manufacturing tolerance of the gear and housing should be kept to the minimum as much as possible based on the conditions of the manufacturing equipment available. This method can make the machined gear have a looser tolerance, thereby obtaining a more economical overall design. 4.1 Relationship between the reference axis and the working axis The reference axis is the axis used by the manufacturer (and the inspector) to determine the gear tooth geometry for a single part. The designer's responsibility is to ensure that the reference axis is determined clearly and accurately enough to ensure that the technical requirements of the gear corresponding to the working axis are met. The most common method to meet this requirement is to determine the reference axis so that it coincides with the working axis, that is, to use the mounting surface as the reference surface. However, in general, it is necessary to first determine a datum axis, and then all other axes (including the working axis and possibly some manufacturing axes) are related to it with appropriate tolerances. In this case, the influence of the added links in the tolerance chain should be taken into account. 4.2 Methods for determining the datum axis
The datum axis of a part is determined by a datum plane. There are three basic methods to achieve it: 4.2.1 The first method is shown in Figure 1. The two points on the axis are determined by the centers of two circles set on two "short" cylindrical or conical datum planes.
4.2.2 The second method is shown in Figure 2. It uses a "long" cylindrical or conical surface to simultaneously determine the position and direction of the axis. The axis of the hole can be represented by the axis of the working mandrel that is matched and correctly assembled. 4.2.3 The third method is shown in Figure 3. The position of the axis is determined by the center of a circle on a "short" cylindrical reference surface, and its direction is determined by a reference end surface perpendicular to this axis. If the first or third method is used, the cylindrical or conical reference surface must be very short in the axial direction to ensure that they do not determine another axis alone. In the third method, the diameter of the reference end surface should be as large as possible. There is often a section on the shaft that is made integral with the pinion where a large gear needs to be installed. The tolerance value of this mounting surface must be selected to be the same as the large 2||tt| |YKAONIKAca
The quality requirements of the gears are in line with each other.
Note: and ? are the predetermined bearing mounting surfaces. Figure 1
GB/Z18620.3—2002
Use two "short" reference surfaces to determine the reference axis B
Figure 2 Use a "long" reference surface to determine the reference axis 4.3 Application of center holes
Figure 3 Use a cylindrical surface and an end surface to determine the base thrust axis During manufacturing and testing, the most common and most satisfactory method for treating the pinion that is made integral with the shaft is to place the part on the tops at both ends. In this way, the two center holes determine its reference axis, and the gear tolerance and the tolerance of the (bearing) mounting surface must be specified relative to this axis (see Figure 4), and it is obvious that the jump of the mounting surface relative to the center hole Dynamic tolerances must be specified to very tight values ​​(see 4.6). Care must be taken to ensure that the center hole is aligned in a straight line within a 60° contact angle. 4.4 Form tolerances of reference surfaces
The required accuracy of the reference surfaces depends on:
the specified gear accuracy, the limit values ​​of these surfaces should be determined much tighter than the limit values ​​of individual gear teeth; the relative position of these surfaces, generally speaking, the larger the proportion of the span to the gear pitch circle diameter, the looser the given tolerance can be. The accuracy requirements of these surfaces must be specified on the part drawing, and the form tolerances of all reference surfaces should not be greater than the values ​​specified in Table 1. Tolerances should be minimized. A
Figure 4 Determination of the reference axis using the center hole
Determination of the axis
Two "short" cylindrical or
conical reference surfaces
One A "long" cylindrical or conical reference surface A short cylindrical surface and an end surface GB/Z18620.3-2002 Table 1 Form tolerance of reference surface and mounting surface Tolerance item 0.04 (L/6) F or 0.1 F Take the smaller of the two Note: The tolerance of gear parts should be reduced to the minimum value that can be manufactured economically. 4.5 Form tolerance of working and manufacturing mounting surfaces Cylindricity 0.04 (L/b) F or 0.1 F Take the smaller of the two Flatness 0.06 (Da/b) Fp The form tolerance of the working mounting surface should not be greater than the value given in Table 1. If another manufacturing mounting surface is used, the same restrictions shall apply.
4.6 Runout tolerance of working axis
If the working mounting surface is selected as the reference surface, this clause is not involved. When the reference axis and the working axis do not coincide, the runout of the working mounting surface relative to the reference axis must be controlled on the drawing. The runout tolerance should not be greater than the values ​​specified in Table 2. Table 2 Runout tolerance of mounting surface
Reference surface for determining axis
Refers to cylindrical or conical reference surface only
One cylindrical reference surface and one end reference surface diameter
Runout (total indication range)
0.15(L/6)F or 0.3F. Take the greater of the two 0.3F
Note: The tolerance of gear teeth should be reduced to the minimum value that can be manufactured economically. 4.7 Mounting surfaces used in gear cutting and testing
0.2(Da/b)F
In manufacturing, when cutting gear teeth to the specified tolerances and in testing, when measuring the actual deviations so that the measured values ​​are sufficiently accurate, it is very important that the gears be mounted during manufacturing and testing so that the actual axis of rotation is as close as possible to the reference axis specified on the drawing.
Unless the mounting surfaces used to mount the gears in manufacturing and testing are the reference surfaces, the position of these mounting surfaces relative to the reference axis must also be controlled. The values ​​given in Table 2 may be used as appropriate tolerance values ​​for these surfaces. To obtain the highest accuracy, as is done in the manufacture of high-quality gears, the position and value of the "high points" of runout are marked near the reference surface, and repeated for a corresponding amount of runout at each step of alignment.
In the strict process control of manufacturing gear parts, a precise expansion mandrel is used to locate the center of the gear part, an appropriate fixture is used to support the gear part so that it can be within the specified runout, and a high-quality gear processing machine is used. On the gear processing machine, the position of the gear part only needs to be checked on the first piece of a batch of workpieces. This step is typical when processing gears in large quantities. For high-precision gears, special reference surfaces must be set (see Figure 5). For very high-precision gears (such as GB/T10095.1 Grade 4 accuracy or higher), the gear needs to be mounted on the shaft before processing. In this case, the shaft neck can be used as the reference surface. 4.8 Tooth tip cylindrical surface
The designer should appropriately select the tolerance of the top circle diameter to ensure the minimum design overlap while having sufficient top clearance. If the tooth tip cylindrical surface is used as the reference surface, the above values ​​can still be used as dimensional tolerances, and its shape tolerance should not be greater than the appropriate value in Table 1. 4.9 Combination of tolerances
When the working axis coincides with the datum axis, or when the tolerance can be specified directly from the working axis, the tolerances in Table 2 may be applied. Not this 4
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GB/Z18620.3—2002
When there is a tolerance chain between the two, it is necessary to appropriately reduce the individual tolerance values ​​in Tables 1 and 2. The degree of reduction depends on the arrangement of the tolerance chain and is generally proportional to the square root of n, where n is the number of links in the tolerance chain. tA
Manufacturing mounting surface-
Working mounting surface = manufacturing mounting surface
-reference surface
Figure 5 High-precision gear with reference surface
For very high-precision gears, it is usually necessary to first install the gear on the shaft and then fine-machine the gear teeth. If this is not possible, the runout of the assembled gear can be measured on its reference surface to show that the required total gear accuracy has been achieved. This measurement can not only detect errors caused by the combined runout of all working mounting surfaces, but also errors caused by the runout of any bearing ring mounted on the shaft.
4.10 Mounting surfaces for other gears
On a shaft that is integral with the pinion, there is often a section where a large gear is mounted. In this case, the tolerance of the mounting surface for the large gear should be selected with due consideration of the quality requirements of the gear teeth. A common and appropriate approach is to specify the permissible runout equivalent to the established datum axis. 4.11 Datum surfaces
Datum surfaces are such (axial and radial) reference strips that are machined to be completely concentric with the actual shaft bore, journal and shoulder of the gear wheel (see Figure 5).
They can be used for alignment when mounted on a gear machine, when mounted on a tester and when finally mounted in use. For workpieces with higher precision, the datum surfaces must also be calibrated and the value and position of the high point of the runout must be marked. This high point and its value should be reproduced in each step of the alignment process to ensure the requirements for very high precision gears. However, many calibration gear units are produced in small batches. In this case, the position of the gears mounted on the gear processing machine must be checked before cutting. Whether to check each gear or part of it depends on the experience of the gear manufacturer. For medium-precision gears, a part of the top cylindrical surface can be used as the radial reference surface, while the axial position can be checked using the mounting surface when the gear is cut. 5 Center distance and parallelism of the axis
The designer should select appropriate tolerances for the two deviations of center distance and parallelism of the axis. The selection of tolerance values ​​should be based on the requirements of its use to ensure the side clearance between the meshing gear teeth and the correct contact in the direction of the tooth length. Providing facilities for adjusting the position of the bearings during assembly may be the most effective technical measure to achieve high precision requirements. However, in many cases, its high cost is difficult to accept. 5.1 Center distance allowable deviation
The center distance tolerance refers to the allowable deviation specified by the designer. The nominal center distance is determined after considering the minimum side clearance and the interference between the tooth tops of the two gears and the root of the non-involute tooth profiles of the meshing gears. In the case of gears that are only loaded in one direction and do not frequently reverse, the control of maximum backlash is not an important consideration. At this time, the allowable deviation of center distance depends mainly on the consideration of overlap. In gears used to control motion, the backlash must be controlled; and when the load on the gear teeth is often reversed, the tolerance of the center distance must be carefully considered for the following factors:
shaft, housing and bearing deflection;
GB/Z18620.3—2002
- misalignment of gear axis due to housing deviation and bearing clearance; - misalignment of gear axis due to housing deviation and bearing clearance; installation error;
- bearing runout;
temperature effects (varies with the temperature difference between the housing and gear parts, center distance and material), centrifugal expansion of rotating parts;
other factors, such as the allowable degree of lubricant contamination and swelling of non-metallic gear materials. When determining the tolerances of all dimensions affecting backlash deviation, the recommendations for tooth thickness tolerance and backlash in GB/Z18620.2 should be followed.
There are other considerations for the selection of the tolerance of the centre distance of high-speed transmissions, which are outside the scope of this document. In gear transmissions, there are situations where one gear drives several gears (or vice versa), such as several planetary gears in a planetary gear transmission; or in the transfer case or power take-off gear of a full-bridge drive vehicle. In this case, in order to obtain proper load distribution and correct working conditions for all meshing, it is necessary to limit the permissible deviation of the centre distance. Such conditions require a detailed study of the working and manufacturing constraints and are outside the scope of this document.
5.2 Axis parallelism tolerance
Since the influence of axis parallelism deviation is related to the direction of its vector, different provisions are made for "deviation in the axis plane" f and "deviation in the vertical plane" f (see Figure 6). The "deviation in the axis plane" f is measured on the common plane of the two axes, which is determined by the longer of the two bearing spans L and a bearing on the other shaft. If the spans of the two bearings are the same, one bearing of the pinion shaft and the gear shaft is used. The "deviation in the vertical plane" f is measured on the "staggered axis plane" perpendicular to the common plane of the axes. Each parallelism deviation is expressed as a value related to the distance L between the relevant shaft bearings ("bearing center distance" L), see Figure 6. The axis deviation in the axis plane affects the helix meshing deviation, and its influence is a sine function of the working pressure angle, while the influence of the axis deviation in the vertical plane is a cosine function of the working pressure angle. It can be seen that the meshing deviation caused by a certain amount of deviation in the vertical plane will be 2 to 3 times larger than the meshing deviation caused by the same size of the in-plane deviation. Therefore, different maximum recommended values ​​should be specified for these two deviation elements. Vertical plane,
5.3 Recommended maximum value of axis deviation
Center distance tolerance
Axis plane
Figure 6 Axis parallelism deviation
a) The recommended maximum value of the deviation fs on the vertical plane is: fsa
b) The recommended maximum value of the deviation fs in the axis plane is: fse=2fsg
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GB/Z18620.3—2002
Appendix A
(Suggested Appendix)
Bibliography
1)GB/T2821—1992
Gear Geometric Element Code
2)GB/T1182-1996 General Rules, Definitions, Symbols and Drawings for Shape and Position Tolerances3)GB/T3374—1992
Basic Gear Terminology||tt ||4)GB/T17851—1999
Form and position tolerance standards and standards system5)GB/Z18620.1—2002
6)GB/Z18620.2-2002
7)GB/Z18620.4—2002
Specification for implementation of cylindrical gear inspection
Part 1: Inspection of tooth flanks on the same side of the gear teeth
Specification for implementation of cylindrical gear inspection
Part 2: Inspection of radial combined deviation, radial runout, tooth thickness and backlash
Specification for implementation of cylindrical gear inspection
Part 4: Inspection of surface structure and tooth contact spots11 Reference surfaces
Reference surfaces are (axial and radial) reference zones which are machined exactly concentric with the actual bore, journal and shoulder of the gear (see Figure 5).
They are used for alignment when mounted on the gear machine, when mounted on the tester and when finally mounted in service. For workpieces of higher precision, the reference surfaces must also be calibrated and the value and position of the high point of run-out must be marked. This high point and its value must be reproduced at each step of the alignment process to ensure the requirements of very high precision gears. However, many calibration gear units are produced in small batches. In this case, the position of the gear mounted on the gear machine must be verified before cutting. Whether this is done for each gear or only for a part depends on the experience of the gear maker. For medium-precision gears, a part of the top cylindrical surface can be used as a radial reference surface, while the axial position can be verified using the mounting surface of the gear when it is cut. 5 Center distance and parallelism of the axis
The designer should select appropriate tolerances for the two deviations of center distance and parallelism of the axis. The selection of tolerance values ​​should be based on the use requirements to ensure the side clearance between the meshing gear teeth and the correct contact in the direction of the tooth length. Providing facilities for adjusting the position of bearings during assembly may be the most effective technical measure to achieve high precision requirements. However, in many cases, its high cost is difficult to accept. 5.1 Center distance allowable deviation
The center distance tolerance refers to the allowable deviation specified by the designer. The nominal center distance is determined after considering the minimum side clearance and the interference between the tooth tops of the two gears and the root parts of the non-involute tooth profiles of the meshing gears. In the case where the gears are only unidirectionally loaded and do not reverse frequently, the control of the maximum side clearance is not an important consideration. At this time, the center distance allowable deviation mainly depends on the consideration of overlap. In gears used to control motion, the backlash must be controlled; and when the load on the gear teeth is often reversed, the tolerance on the center distance must be carefully considered:
shaft, housing and bearing deflection
GB/Z18620.3—2002
- misalignment of the gear axis due to housing deviation and bearing clearance; - misalignment of the gear axis due to housing deviation and bearing clearance; installation errors
- bearing runout;
temperature effects (varies with the temperature difference between housing and gear parts, center distance and material differences), centrifugal expansion of rotating parts;
other factors, such as the allowable degree of lubricant contamination and swelling of non-metallic gear materials. When determining the tolerances of all dimensions that affect backlash deviation, the recommendations for tooth thickness tolerance and backlash in GB/Z18620.2 should be followed.
The selection of center distance tolerances for high-speed transmissions, as well as other considerations, are beyond the scope of this document. In gear transmissions, there are situations where one gear drives several gears (or vice versa), such as several planetary gears in a planetary gear transmission; or in the transfer case or power take-off gear of a full-bridge drive vehicle. In this case, in order to obtain proper load distribution and correct working conditions for all meshing, it is necessary to limit the permissible deviation of the center distance. This condition requires a detailed study of the working and manufacturing constraints and is not within the scope of this document.
5.2 Axis parallelism tolerance
Since the influence of axis parallelism deviation is related to the direction of its vector, different provisions are made for the "axis plane deviation" f and the "vertical plane deviation" f (see Figure 6). The "axis plane deviation" f is measured in the common plane of the two axes. This common plane is determined by the longer of the two bearing spans L and a bearing on the other shaft. If the spans of the two bearings are the same, one bearing of the pinion shaft and the gear shaft is used. The "vertical plane deviation" f is measured in the "staggered axis plane" perpendicular to the common plane of the axes. Each parallelism deviation is expressed as a value related to the distance L between the relevant shaft bearings ("bearing center distance" L), see Figure 6. The axis deviation in the axis plane affects the helix meshing deviation, and its influence is a sine function of the working pressure angle, while the influence of the axis deviation in the vertical plane is a cosine function of the working pressure angle. It can be seen that the meshing deviation caused by a certain amount of deviation in the vertical plane will be 2 to 3 times larger than the meshing deviation caused by the same size of in-plane deviation. Therefore, different maximum recommended values ​​should be specified for these two deviation elements. Vertical plane,
5.3 Recommended maximum value of axis deviation
Center distance tolerance
Axis plane
Figure 6 Axis parallelism deviation
a) The recommended maximum value of the deviation fs in the vertical plane is: fsa
b) The recommended maximum value of the deviation fs in the axis plane is: fse=2fsg
KAONiKAca
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（2）
GB/Z18620.3—2002
Appendix A
(Suggested Appendix)
Bibliography
1)GB/T2821—1992
Gear Geometric Element Code
2)GB/T1182-1996 General Rules, Definitions, Symbols and Drawings for Shape and Position Tolerances3)GB/T3374—1992
Basic Gear Terminology||tt ||4)GB/T17851—1999
Form and position tolerance standards and standards system5)GB/Z18620.1—2002
6)GB/Z18620.2-2002
7)GB/Z18620.4—2002
Specification for implementation of cylindrical gear inspection
Part 1: Inspection of tooth flanks on the same side of the gear teeth
Specification for implementation of cylindrical gear inspection
Part 2: Inspection of radial combined deviation, radial runout, tooth thickness and backlash
Specification for implementation of cylindrical gear inspection
Part 4: Inspection of surface structure and tooth contact spots11 Reference surfaces
Reference surfaces are (axial and radial) reference bands which are machined exactly concentric with the actual bore, journal and shoulder of the gear wheel (see Figure 5).
They are used for alignment when mounted on the gear machine, when mounted on the tester and when finally mounted in service. For workpieces of higher precision, the reference surfaces must also be calibrated and the value and position of the high point of run-out must be marked. This high point and its value must be reproduced at each step of the alignment process to ensure the requirements of very high precision gears. However, many calibration gear units are produced in small batches. In this case, the position of the gear mounted on the gear machine must be verified before cutting. Whether this is done for each gear wheel or only for a part depends on the experience of the gear maker. For medium-precision gears, a part of the top cylindrical surface can be used as a radial reference surface, while the axial position can be verified using the mounting surface of the gear when it is cut. 5 Center distance and parallelism of the axis
The designer should select appropriate tolerances for the two deviations of center distance and parallelism of the axis. The selection of tolerance values ​​should be based on the use requirements to ensure the side clearance between the meshing gear teeth and the correct contact in the direction of the tooth length. Providing facilities for adjusting the position of bearings during assembly may be the most effective technical measure to achieve high precision requirements. However, in many cases, its high cost is difficult to accept. 5.1 Center distance allowable deviation
The center distance tolerance refers to the allowable deviation specified by the designer. The nominal center distance is determined after considering the minimum side clearance and the interference between the tooth tops of the two gears and the root parts of the non-involute tooth profiles of the meshing gears. In the case where the gears are only unidirectionally loaded and do not reverse frequently, the control of the maximum side clearance is not an important consideration. At this time, the center distance allowable deviation mainly depends on the consideration of overlap. In gears used to control motion, the backlash must be controlled; and when the load on the gear teeth is often reversed, the tolerance on the center distance must be carefully considered:
shaft, housing and bearing deflection
GB/Z18620.3—2002
- misalignment of the gear axis due to housing deviation and bearing clearance; - misalignment of the gear axis due to housing deviation and bearing clearance; installation errors
- bearing runout;
temperature effects (varies with the temperature difference between housing and gear parts, center distance and material differences), centrifugal expansion of rotating parts;
other factors, such as the allowable degree of lubricant contamination and swelling of non-metallic gear materials. When determining the tolerances of all dimensions that affect backlash deviation, the recommendations for tooth thickness tolerance and backlash in GB/Z18620.2 should be followed.
The selection of center distance tolerances for high-speed transmissions, as well as other considerations, are beyond the scope of this document. In gear transmissions, there are situations where one gear drives several gears (or vice versa), such as several planetary gears in a planetary gear transmission; or in the transfer case or power take-off gear of a full-bridge drive vehicle. In this case, in order to obtain proper load distribution and correct working conditions for all meshing, it is necessary to limit the permissible deviation of the center distance. This condition requires a detailed study of the working and manufacturing constraints and is not within the scope of this document.
5.2 Axis parallelism tolerance
Since the influence of axis parallelism deviation is related to the direction of its vector, different provisions are made for the "axis plane deviation" f and the "vertical plane deviation" f (see Figure 6). The "axis plane deviation" f is measured in the common plane of the two axes. This common plane is determined by the longer of the two bearing spans L and a bearing on the other shaft. If the spans of the two bearings are the same, one bearing of the pinion shaft and the gear shaft is used. The "vertical plane deviation" f is measured in the "staggered axis plane" perpendicular to the common plane of the axes. Each parallelism deviation is expressed as a value related to the distance L between the relevant shaft bearings ("bearing center distance" L), see Figure 6. The axis deviation in the axis plane affects the helix meshing deviation, and its influence is a sine function of the working pressure angle, while the influence of the axis deviation in the vertical plane is a cosine function of the working pressure angle. It can be seen that the meshing deviation caused by a certain amount of deviation in the vertical plane will be 2 to 3 times larger than the meshing deviation caused by the same size of in-plane deviation. Therefore, different maximum recommended values ​​should be specified for these two deviation elements. Vertical plane,
5.3 Recommended maximum value of axis deviation
Center distance tolerance
Axis plane
Figure 6 Axis parallelism deviation
a) The recommended maximum value of the deviation fs in the vertical plane is: fsa
b) The recommended maximum value of the deviation fs in the axis plane is: fse=2fsg
KAONiKAca
（1）
（2）
GB/Z18620.3—2002
Appendix A
(Suggested Appendix)
Bibliography
1)GB/T2821—1992
Gear Geometric Element Code
2)GB/T1182-1996 General Rules, Definitions, Symbols and Drawings for Shape and Position Tolerances3)GB/T3374—1992
Basic Gear Terminology||tt ||4)GB/T17851—1999
Form and position tolerance standards and standards system5)GB/Z18620.1—2002
6)GB/Z18620.2-2002
7)GB/Z18620.4—2002
Specification for implementation of cylindrical gear inspection
Part 1: Inspection of tooth flanks on the same side of the gear teeth
Specification for implementation of cylindrical gear inspection
Part 2: Inspection of radial combined deviation, radial runout, tooth thickness and backlash
Specification for implementation of cylindrical gear inspection
Part 4: Inspection of surface structure and tooth contact spots2 Axis parallelism tolerance
Since the influence of axis parallelism deviation is related to the direction of its vector, different provisions are made for "deviation in axis plane" f and "deviation in vertical plane" f (see Figure 6). "Deviation in axis plane" f is measured on the common plane of the two axes. This common plane is determined by the longer of the two bearing spans L and a bearing on the other axis. If the spans of the two bearings are the same, a bearing of the pinion shaft and the gear shaft is used. "Deviation in vertical plane" f is measured on the "staggered axis plane" perpendicular to the common plane of the axes. Each parallelism deviation is expressed as a value related to the distance L between the relevant axis bearings ("bearing center spacing" L), see Figure 6. The axis deviation in the axis plane affects the helical meshing deviation, and its influence is the sine function of the working pressure angle, while the influence of the axis deviation in the vertical plane is the cosine function of the working pressure angle. It can be seen that the meshing deviation caused by a certain amount of vertical plane deviation will be 2 to 3 times larger than the meshing deviation caused by the same size of plane deviation. Therefore, different maximum recommended values ​​are required for these two deviation elements. Vertical plane,
5.3 Recommended maximum value of axis deviation
Center distance tolerance
Axis plane
Figure 6 Axis parallelism deviation
a) The recommended maximum value of the deviation fs on the vertical plane is: fsa
b) The recommended maximum value of the deviation fs in the axis plane is: fse=2fsg
KAONiKAca
（1）
（2）
GB/Z18620.3—2002
Appendix A
(Suggested Appendix)
Bibliography
1)GB/T2821—1992
Gear Geometric Element Code
2)GB/T1182-1996 General Rules, Definitions, Symbols and Drawings for Shape and Position Tolerances3)GB/T3374—1992
Basic Gear Terminology||tt ||4)GB/T17851—1999
Form and position tolerance standards and standards system5)GB/Z18620.1—2002
6)GB/Z18620.2-2002
7)GB/Z18620.4—2002
Specification for implementation of cylindrical gear inspection
Part 1: Inspection of tooth flanks on the same side of the gear teeth
Specification for implementation of cylindrical gear inspection
Part 2: Inspection of radial combined deviation, radial runout, tooth thickness and backlash
Specification for implementation of cylindrical gear inspectionwwW.bzxz.Net
Part 4: Inspection of surface structure and tooth contact spots2 Axis parallelism tolerance
Since the influence of axis parallelism deviation is related to the direction of its vector, different provisions are made for "deviation in axis plane" f and "deviation in vertical plane" f (see Figure 6). "Deviation in axis plane" f is measured on the common plane of the two axes. This common plane is determined by the longer of the two bearing spans L and a bearing on the other axis. If the spans of the two bearings are the same, a bearing of the pinion shaft and the gear shaft is used. "Deviation in vertical plane" f is measured on the "staggered axis plane" perpendicular to the common plane of the axes. Each parallelism deviation is expressed as a value related to the distance L between the relevant axis bearings ("bearing center spacing" L), see Figure 6. The axis deviation in the axis plane affects the helical meshing deviation, and its influence is the sine function of the working pressure angle, while the influence of the axis deviation in the vertical plane is the cosine function of the working pressure angle. It can be seen that the meshing deviation caused by a certain amount of vertical plane deviation will be 2 to 3 times larger than the meshing deviation caused by the same size of plane deviation. Therefore, different maximum recommended values ​​are required for these two deviation elements. Vertical plane,
5.3 Recommended maximum value of axis deviation
Center distance tolerance
Axis plane
Figure 6 Axis parallelism deviation
a) The recommended maximum value of the deviation fs on the vertical plane is: fsa
b) The recommended maximum value of the deviation fs in the axis plane is: fse=2fsg
KAONiKAca
（1）
（2）
GB/Z18620.3—2002
Appendix A
(Suggested Appendix)
Bibliography
1)GB/T2821—1992
Gear Geometric Element Code
2)GB/T1182-1996 General Rules, Definitions, Symbols and Drawings for Shape and Position Tolerances3)GB/T3374—1992
Basic Gear Terminology||tt ||4)GB/T17851—1999
Form and position tolerance standards and standards system5)GB/Z18620.1—2002
6)GB/Z18620.2-2002
7)GB/Z18620.4—2002
Specification for implementation of cylindrical gear inspection
Part 1: Inspection of tooth flanks on the same side of the gear teeth
Specification for implementation of cylindrical gear inspection
Part 2: Inspection of radial combined deviation, radial runout, tooth thickness and backlash
Specification for implementation of cylindrical gear inspection
Part 4: Inspection of surface structure and tooth contact spots
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