JB/T 3712-1998 JB/T 3712-1998 Small torsion spring comparator JB/T3712-1998 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T3712—1998
Small Torsion Spring Comparator
Published on July 17, 1998
National Bureau of Machinery Industry
Implementation on December 1, 1998
JB/T3712—1998
This standard is formulated after modifying JB3712-84 "Small Torsion Spring Comparator". According to the development of production and technology, the original standard has been modified as follows:
The definition of indication error has been modified;
-The values ​​of measured force and force change have been modified;-The indication range of indication error has been adjusted:-Article 5.13 has been added;
-Appendix A in the original standard has been deleted, and the content has been rewritten into the main text of the standard. This standard will replace JB3712-84 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Standardization of Measuring Tools and Instruments. The drafting unit of this standard: Harbin Measuring Tools and Cutting Tools Factory. The main drafters of this standard: Li Jianyi, Gao Shanming, Xu Qiankang. 1 Scope
Mechanical Industry Standard of the People's Republic of China
Small Torsion Spring Comparator
This standard applies to small torsion spring comparators with a sleeve diameter of 8mm (hereinafter referred to as comparators). 2 Referenced Standards
JB/T3712-1998
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB 487985
ZBJ08004—88
3 Terminology
3.1 Torsion spring comparator
Rust-proof packaging
Technical conditions for transportation packaging of measuring tools and cutting tools
Torsion spring comparator is a measuring instrument that uses a torsion spring strip with a linear relationship between axial elongation and rotation angle as the main amplification element to convert the linear displacement of the measuring rod into the angular displacement of the pointer, and is used to measure the size and form and position errors of workpieces. 3.2 Indication error
Indication error is the difference between the indication value of the inspected point relative to the zero position and the (agreed) true value. 3.3 Radial force indication change
Radial force indication change refers to the maximum change value of the pointer relative to the original position when the comparator is clamped on the comparator seat, the measuring head contacts the gauge block, and force is applied perpendicular to the axis of the measuring rod, front, back, left, and right, near the measuring head. 4 Type, basic parameters and dimensions
The scale value and indication range of the comparator are shown in Table 1. Table 1 The scale value and indication range of the comparator
The type and structure of the comparator are shown in Figure 1 (the structure shown is for reference) Approved by the State Bureau of Machinery Industry on July 17, 1998
Implementation on December 1, 1998
5 Technical requirements
JB/T3712-1998
1-Measuring head; 2-Sleeve: 3-Zero adjustment device: 4-Case: 5-Dial: 6 Pointer Figure 1
The comparator should not have defects such as paint removal, chrome removal, rust and scratches that obviously affect the appearance. 5.1
5.2 The movement of the measuring mechanism of the comparator should be smooth and flexible, without sticking: the pointer can return to the left scale line in the free state. 5.3 The comparator should have a zero adjustment device with an adjustment range of not less than 5 divisions and a travel limiter to limit the travel of the measuring rod. 5.4 The distance between the scale lines should be not less than 0.9mm. The width of the pointer tip and the scale line width on the dial are 0.1~0.2mm, and the difference between the width of the pointer tip and the scale line width on the dial should not exceed 0.05mm. 5.5 The pointer tip of the comparator should cover 30%~80% of the length of the short scale line on the dial. There should be a circular mark of not less than 1mm at 3~5mm from the pointer tip, and the mark and the pointer tip should be painted red, black or other eye-catching colors. 5.6 The distance between the pointer tip of the comparator and the scale dial should not be greater than 1mm. 5.7 The measuring head should be made of wear-resistant materials such as agate or cemented carbide. For steel measuring heads, the hardness of the measuring surface should not be less than 760HV (~62HRC).
5.8 The maximum allowable value of the surface roughness R of the measuring head is 0.04μm. 5.9 The force measurement and force measurement change of the comparator are specified in Table 2. 2
JB/T3712-1998
Force measurement and force measurement change
The radial force indication change of the comparator is specified in Table 3. Force
Table 3 Radial force indication change
The indication error and indication variability of the comparator are specified in Table 4. Force
Indication error and indication variability
Graduation value
±30 divisions
±0.00015
2 The pointer swing time during measurement should not exceed 1s5.12
±50 divisions
Force measurement change
(division)
Indication variability
(division)
3 The balance of the pointer should not exceed 1/3 of the division, and the balance of the comparator pointer with a division value of 0.0002mm should not exceed 2/35.13
Division.
Test method
6.1 Appearance
Visual observation.
Interaction
Hand feel test.
6.3 Pointer swing time
JB/T3712-1998
While checking the variability of the indication, observe the time when the pointer stops swinging. In case of dispute, it can be determined by a video recorder. 6.4 Force measurement, force change and force drop
The comparator is reliably mounted on a special force measuring device with a graduation value of 0.05N. 6.4.1 Force measurement
When the measuring rod is raised from the starting point to make the pointer return to the maximum indication range, the measured force should not exceed the specified value. 6.4.2 Force change
Within the entire indication range, the difference between the maximum and minimum values ​​of the measured force in the forward and reverse strokes is the force change 6.5 Radial force indication change
The comparator is reliably mounted on a bracket with good rigidity, so that its measuring head is in vertical contact with the gauge block on the workbench, and then the pointer is adjusted to the zero position of the dial. Use a professional force gauge to act on the measuring head and perpendicular to the direction of the measuring rod. When measuring, pull the test in the front, back, left and right directions. The maximum value of the change in the indication in the four directions is the change in the radial force indication. 6.6 Balance of the pointer
Install the comparator reliably on the special fixture, adjust the zero position, and when the comparator orientation is changed arbitrarily, the maximum change range of the pointer position should not exceed the specified value.
6.7 Indication variability
Install the comparator reliably on the comparator seat with good rigidity, so that the measuring head contacts the gauge block. When the pointer is at the zero mark and the maximum position of the marks on both sides, move the measuring rod 5 to 7 times. The difference between the maximum and minimum indications is the indication variability. 6.8 Indication error
Install the comparator securely on the rigid comparator seat, make the measuring head contact with the gauge block, and adjust the pointer to zero. Use the +30, +50, -30, -50 divisions on both sides of the zero position as the inspection points, and use the gauge block for calibration. Table 5 gives an example of the indication error and evaluation results of three comparators after calibration. Table 5 Indication error and evaluation results after calibration Indication range
(division)
± 50 divisions
7 Marking and packaging
Graduation value
7.1 The comparator should be marked with: bzxz.net
a) manufacturer's name or trademark;
b) Graduation value;
c) product serial number;
The difference between the indication value and the true value of each inspection point
d) The dial should be marked with "+" and "-". 4
Indication error
±30 divisions
±50 divisions
Evaluation result
Unqualified
The packaging box of the comparator should indicate:
a) Product name:
b) Manufacturer name or trademark;
c) Graduation value;
d) Indication range.
JB/T3712—1998
The packaging and anti-rust treatment of the comparator should comply with the requirements specified in GB4879 and ZBJ08004. 7.3
7.4 The comparator should be accompanied by a product certificate. The product certificate should be marked with the standard number of the adopted product standard, product number and factory date. 5
Mechanical Industry Standard
JB/T3712-1998
Published by the Mechanical Standardization Research Institute of the Ministry of Machinery Industry Printed by the Mechanical Standardization Research Institute of the Ministry of Machinery Industry (No. 2 Shouti South Road, Beijing: Postal Code 100044)*
Format 880×1230
Printing Sheet 1/2
Word Count 10000
First Printing in October 1998
First Edition in October 1998
Print Quantity 00,001-500
Cost 5.00 yuan
98-112
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.