Some standard content:
ICS 65.060.10; 43.160
B90; T54
Machinery Industry Standard of the People's Republic of China
JB/T7283-2001
Agricultural Machinery Leaf Spring
Leafspringforagriculturalmachinery2001-06-22 Issued
China Machinery Industry Federation
2001-10-01 Implementation
JB/T7283-2001
This standard is a revision of B/T7283-1994 "Technical Conditions for Agricultural Machinery Leaf Spring". Compared with JB/T7283-1994, the main technical content changes of this standard are as follows: Added the definition of permanent deformation and temporary deformation; Deleted the deflection index:
- Added the fatigue life index of the main and auxiliary composite leaf springs;- Supplemented the test method content.
This standard replaces JB/T7283-1994 from the date of implementation. This standard is proposed and managed by the National Agricultural Machinery Standardization Technical Committee. The responsible drafting units of this standard are: China Agricultural Mechanization Science Research Institute, National Agricultural Machinery Quality Supervision and Inspection Center, Parts Branch of the 3403 Factory of the Chinese People's Liberation Army, and Anqing Leaf Spring Factory. The main drafters of this standard are: Chen Ge and Zheng Qingshan. This standard was first issued in July 1994, and this is the first revision. 1 Scope
Machinery Industry Standard of the People's Republic of China
Leaf spring for agricultural machinery
Leaf spring for agricultural madhineryJB/T7283-2001
Replaces JB/T7283-1994
This standard specifies the technical requirements, test methods, inspection rules, marking, transportation and storage of leaf springs for agricultural machinery. This standard applies to leaf springs (hereinafter referred to as leaf springs) with linear (equal stiffness) and nonlinear (variable stiffness) characteristics for agricultural trailers and agricultural transport vehicles. Other similar products may also refer to this standard for implementation. 2 Referenced standards
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/T 1222—1984
GB/T 18051986
GB/T 2828—1987
JB/T5673—1991
3 Definitions
Spring steel
Spring terminology
Batch inspection counting sampling procedure and sampling table (applicable to continuous batch inspection) General technical conditions for painting of agricultural and forestry tractors and machinery This standard adopts the definitions specified in GB/T1805 and the following definitions. 3.1
Camber
The maximum vertical distance between the line connecting the two supporting points of the leaf spring and the first concave surface h, mm. 3.2
Free camber
The arc height of the leaf spring when it is unloaded ho, mm4
Camber under specified loadThe arc height of the leaf spring under the rated vertical load, referred to as "static arc height" he, mm. Permanent deformation and temporary deformation
permanent defomation, temporary defamationThe part of the change in the free height and arc height of the leaf spring after unloading that cannot be restored is called permanent deformation, and the part that can be restored is called temporary deformation (called hysteresis elastic deformation).
Spring assembly
The product assembled according to the requirements of the leaf spring product drawing. Assembly widthwidthofspringassembly3.6
The width of the leaf spring product within the clamping range of the U-bolt and the sliding part of the bracket. Width of a roll
The width of the spring at the roll part.
Approved by China Machinery Industry Federation on June 22, 2001, implemented on October 1, 2001
3.8 Mainleaf
JB/T7283—2001
A spring with a roll or a sliding part of a bracket. 3.9 Working limit load woikingultimateloadThe maximum load that may occur during the operation of the spring. 4 Technical requirements
4.1 Manufacturing quality
4.1.1 Products shall be manufactured in accordance with drawings and technical documents approved by the prescribed procedures. The drawings and technical documents shall make clear requirements for the rated load, static load arc height, and stiffness under the specified load. 4.1.2 The material used for the leaf spring is hot-rolled spring flat steel, which shall be selected in accordance with the provisions of GB/T1222. If other new materials are used, their performance indicators must meet the requirements of this standard.
4.1.3 The surface of the spring should not have defects such as overburning, cracks and flash that are harmful to use. 4.1.4 The width of the ear of the spring with ear should have a dimensional accuracy of not less than JS16. 4.1.5 The dimensional accuracy of the installation center distance at both ends of the assembly main piece in the straight state should not be less than JS16, and the dimensional accuracy from one end to the center hole (or positioning convex bump) should not be less than JS16.
4.1.6 After heat treatment, the medium and high carbon spring steel is tempered with troostite 1~5, and the low carbon spring steel is tempered with martensite 1~4. The depth of the decarburized layer is not more than 3% of the thickness of the spring flat steel. The tensile surface of the main leaf spring and the variable cross-section leaf should be shot peened. 4.1.7 If the purchaser has special requirements for the manufacturing quality of the leaf spring, it can be negotiated with the manufacturer and indicated in technical documents such as product drawings. 4.2 Assembly quality
4.2.1 Graphite grease should be applied between the spring leaves (except for those with gaskets between the leaves). 4.2.2 The deviation of the free arc height of the assembly, the deviation of the width of the assembly and the tolerance of the bore of the ear bushing should comply with the provisions of Table 1. Table 1
Free arc height deviation
Assembly width deviation
Tolerance of bore of the ear bushing
Metal bushing
Non-metal bushing
±10% (maximum value does not exceed 100mm)
Note: When the spring leaf installed in the sliding part of the bracket is variable width, its width should comply with the provisions of the product drawing. 4.2.3 The leaf spring assembly with ear should not be loose after being pressed into the bushing. The parallelism of its axis and the installation base surface and the verticality of the longitudinal center plane should not exceed 1.0%. The verticality of the end contact working surface of the leaf spring without ear and the longitudinal center plane should not exceed 1.0%. As shown in Figure 1. 4.2.4 The surface of the leaf spring assembly (including single-piece accessories) shall be painted and the coating shall be uniform. There shall be no paint stains in the bushing hole of the leaf spring with ear. Other anti-rust measures shall be taken for the metal bushing.
4.2.5 If the purchaser has special requirements for the assembly quality of the leaf spring, it can be agreed with the manufacturer and indicated in the product drawings and other technical documents. 2
Performance index
7283—2001
4.3.1 The permanent deformation and temporary deformation of the leaf spring after strong pressure treatment shall not exceed 0.5mm. ≤2.0
4.3.2 The stiffness and static arc height deviation of the linear characteristic leaf spring under the rated load, and the stiffness and static arc height deviation of the nonlinear characteristic leaf spring under the specified load shall comply with the provisions of Table 2. The main and auxiliary composite leaf springs shall ensure that the working surface of the auxiliary leaf spring is fully in contact under the rated static load, specified load and reference load.
Static arc height or arc height deviation under specified load
Stiffness or stiffness deviation under specified load
Bench fatigue life
Main machine load mass<50mg
Main machine load mass≥5000kg
Rated stiffness<95N/mm
Rated stiffness≥95N/mm
± 10 %
The bench fatigue life of leaf springs (except main and auxiliary composite leaf springs) under vertical load shall comply with the provisions of Table 3. Table 3
Stress amplitude
≤285
>285~325
>325-365
Note: The stresses involved in this standard refer to the average stress. Bench fatigue life
(times)
≥10×10+
≥6×104
≥4×10*
≥3×104
The bench fatigue life of the main and auxiliary composite leaf springs under vertical load shall not be less than 4×104 times. 4.4. 2
5 Test method
5.1 Performance index determination
7283—2001
It shall be carried out on a special leaf spring testing machine (the loading and unloading processes of the testing machine shall be inspected and calibrated). 5.1.1 Support and clamping method
The support method of the spring with ear is shown in Figure 2. The ear is supported on a pulley equipped with rollers by a pin, and other structural springs are supported according to the support method specified in the product drawings and other technical documents. The middle part of the spring is in a free state during loading and unloading, and the load is applied through the loading block shown in Figure 3.
5.1.2 Test method
≥ spring plate width
5.1.2.1 The leaf spring is subjected to three strong pressures according to the working limit load specified in the product drawing. The loading and unloading must be slow and continuous. 5.1.2.2 During the third strong pressure, measure and record the free arc height before and after the strong pressure, and the arc height values under loading and unloading to 0.7 times, 1.0 times and 1.3 times the rated load. For nonlinear leaf springs, the arc height values under the specified load and reference load must also be measured and recorded. 5.1.2.3 The measurement must be carried out after the loading and unloading is stable and stationary. 5.1.2.4 Permanent deformation and temporary deformation, static arc height, stiffness value d, h., C are calculated according to formula (1), formula (2) and formula (3) respectively: Permanent deformation and temporary deformation:
d=h plus oh
Permanent deformation and temporary deformation, mm;
Where: d
hmo--free arc height before the third loading and unloading, mm; h--free arc height after the third loading and unloading, mm. Static arc height:
hme+he
Where: h static arc height, mm;
h plus e--arc height when the third loading is loaded to the rated load, mm; h.
-arc height when the third unloading is unloaded to the rated load, mm. Stiffness value C (unit Nmm):
C=C++C, +C,+c.
7283—2001
C,, C,, C, in formula (3) are calculated according to formula (4): C
Where: 1=1, 2, 3, 4.
△ P=1.3P,-P,=P-0.7P,:
P—rated load, N;
Deformation corresponding to each △P during loading and unloading, mm, Af
5.1.2.5For leaf spring assemblies with nonlinear characteristics, the stiffness value under a specified load is still measured by the above method using the two-point method and calculated according to formula (5):
Af loading+Af unloading
Where: C refers to the measured stiffness value of a leaf spring under a specified load, Nmm; △P is the difference between the specified load and the reference load, given by the drawing, N: A coffee, Af is the deformation corresponding to each △P during loading and unloading, mm. The bench fatigue life determination
test is carried out on a leaf spring fatigue testing machine. 5.2.1 Support and clamping method
The support method of the spring with ear is shown in Figure 2. The ears are supported on the pulley with rollers by pins, and other structural springs are supported according to the actual installation state on the vehicle or a state similar in function. The middle part is clamped according to the actual installation state on the vehicle or a state similar in function. The clamping must meet the following conditions:
a) The upper and lower clamps are manufactured according to Figure 4, and their dimensions are shown in Table 4. $20
Agricultural trailer
Four-wheel agricultural
Transport vehicle
7C1-7CC3
7CC3-7CC7
Rear and auxiliary
Three-wheel agricultural transport vehicle
Upper clamp
b) See Table 5 for clamping bolts and clamping torque. Vehicle
Agricultural trailer
Four-wheel agricultural
Transport vehicle
7C1.5, 7CC2
7CB2, 7CC3, 7CC4
7CB3, 7CC5-7CC7
0.75t, 1.0
Three-wheel agricultural transport vehicle
5.2.2 Test method
Lower pad
Upper clamping plate
Clamping bolt diameter
Lower pad
Clamping bolt center distance
Before the test, the static deformation F and clamping stiffness C in the clamped state shall be measured. 5.2.2.1
Upper clamp
Lower pad
Clamping torque
98~127
166186
245~294
98~127
127~147
5.2.2.2 During the bench fatigue life test, the pre-deformation and pulsation amplitude are calculated by formula (6) and formula (7): Pre-deformation F (unit: mm):
Fm = 0.6(F + BF
Pulsation amplitude F. (unit: mm):
F=0.4(F, +βJF,
Where: F is the static deformation of the leaf spring under rated load in the clamped state, calculated according to the measured value of the sample under test, cm; β is the spring type coefficient. Agricultural trailer leaf spring: β=2.5; four-wheel agricultural transport vehicle leaf spring: front assembly β=2.5, rear assembly β=2.0, auxiliary spring assembly is based on the main spring assembly: three-wheel agricultural transport vehicle leaf spring: β=2.0. Note: If the limit deformation calculated according to the formula exceeds the maximum allowable stress of the leaf spring material, the test parameters are corrected with the limit deformation corresponding to the maximum stress value. The stress amplitude of the leaf spring is calculated according to formula (8) to formula (14): Fmax =Fm+ F
Where: Fmar
-maximum deflection, mm.
Fmin=Fm-F
Where: Fmin——minimum deflection, mm. 6
Where: Pmc
Where: Pmm
Where: 0m
Where: Onin
Where: 0-
Maximum force, N;
Clamping stiffness of leaf spring, N/mm.
Minimum force, N.
Maximum stress, MPa;
7283-2001
Pmm=FmmC
Pmax Ln
Section modulus of the leaf spring assembly, mm;
Effective length of the leaf spring, mm.
Minimum stress, MPa.
-Stress amplitude, MPa.
Pmin Ln
（10）
（13)
（14）
5.2.2.3 When the test is carried out to 1.0×104, 3.0×104, 6.0×104 and 9.0×104 times, adjust the torque and preload of the tightening bolts to the specified values.
5.2.2.4 The surface temperature of the sample shall not exceed 150℃ during the test. 5.2.2.5 In a leaf spring sample , the number of cycles when any piece of steel plate first appears macro cracks (cracks through the thickness direction on both sides of the same part) is the life of the sample. 5.3 Determination of free arc height
Use general measuring tools to detect when testing performance items. 5.4
Determination of bushing aperture
Use plug gauges for detection.
5.5 Determination of verticality of rolled ears
Use special inspection tools or a combination of general measuring tools for detection. 5 Determination of parallelism and verticality
Use special inspection tools or a combination of general measuring tools for detection. Determination of assembly width
Use a card plate or caliper for detection.
5.8 Determination of rolled ear width
Use a card plate or caliper for detection.
Surface quality inspection
Use visual inspection.
6 Inspection rules
The inspection of leaf springs is divided into factory inspection and type inspection. 74 Permanent deformation and temporary deformation, static arc height, stiffness value d, h., C are calculated according to formula (1), formula (2) and formula (3) respectively: Permanent deformation and temporary deformation:
d=h plus oh
Permanent deformation and temporary deformation, mm;
Where: d
hmo--free arc height before the third loading and unloading, mm; h--free arc height after the third loading and unloading, mm. Static arc height:
hme+he
Where: h static arc height, mm;
h plus e--arc height when the third loading is loaded to the rated load, mm; h.
-arc height when the third unloading is unloaded to the rated load, mm. Stiffness value C (unit Nmm):
C=C++C, +C,+c.
7283—2001
C,, C,, C, in formula (3) are calculated according to formula (4): C
Where: 1=1, 2, 3, 4.
△ P=1.3P,-P,=P-0.7P,:
P—rated load, N;
Deformation corresponding to each △P during loading and unloading, mm, Af
5.1.2.5For leaf spring assemblies with nonlinear characteristics, the stiffness value under a specified load is still measured by the above method using the two-point method and calculated according to formula (5):
Af loading+Af unloading
Where: C refers to the measured stiffness value of a leaf spring under a specified load, Nmm; △P is the difference between the specified load and the reference load, given by the drawing, N: A coffee, Af is the deformation corresponding to each △P during loading and unloading, mm. The bench fatigue life determination
test is carried out on a leaf spring fatigue testing machine. 5.2.1 Support and clamping method
The support method of the spring with ear is shown in Figure 2. The ears are supported on the pulley with rollers by pins, and other structural springs are supported according to the actual installation state on the vehicle or a state similar in function. The middle part is clamped according to the actual installation state on the vehicle or a state similar in function. The clamping must meet the following conditions:
a) The upper and lower clamps are manufactured according to Figure 4, and their dimensions are shown in Table 4. $20
Agricultural trailer
Four-wheel agricultural
Transport vehicle
7C1-7CC3
7CC3-7CC7
Rear and auxiliary
Three-wheel agricultural transport vehicle
Upper clamp
b) See Table 5 for clamping bolts and clamping torque. Vehicle
Agricultural trailer
Four-wheel agricultural
Transport vehicle
7C1.5, 7CC2
7CB2, 7CC3, 7CC4
7CB3, 7CC5-7CC7
0.75t, 1.0
Three-wheel agricultural transport vehicle
5.2.2 Test method
Lower pad
Upper clamping plate
Clamping bolt diameter
Lower pad
Clamping bolt center distance
Before the test, the static deformation F and clamping stiffness C in the clamped state shall be measured. 5.2.2.1
Upper clamp
Lower pad
Clamping torque
98~127
166186
245~294
98~127
127~147
5.2.2.2 During the bench fatigue life test, the pre-deformation and pulsation amplitude are calculated by formula (6) and formula (7): Pre-deformation F (unit: mm):
Fm = 0.6(F + BF
Pulsation amplitude F. (unit: mm):
F=0.4(F, +βJF,
Where: F is the static deformation of the leaf spring under rated load in the clamped state, calculated according to the measured value of the sample under test, cm; β is the spring type coefficient. Agricultural trailer leaf spring: β=2.5; four-wheel agricultural transport vehicle leaf spring: front assembly β=2.5, rear assembly β=2.0, auxiliary spring assembly is based on the main spring assembly: three-wheel agricultural transport vehicle leaf spring: β=2.0. Note: If the limit deformation calculated according to the formula exceeds the maximum allowable stress of the leaf spring material, the test parameters are corrected with the limit deformation corresponding to the maximum stress value. The stress amplitude of the leaf spring is calculated according to formula (8) to formula (14): Fmax =Fm+ F
Where: Fmar
-maximum deflection, mm.
Fmin=Fm-F
Where: Fmin——minimum deflection, mm. 6
Where: Pmc
Where: Pmm
Where: 0m
Where: Onin
Where: 0-
Maximum force, N;
Clamping stiffness of leaf spring, N/mm.
Minimum force, N.
Maximum stress, MPa;
7283-2001
Pmm=FmmC
Pmax Ln
Section modulus of the leaf spring assembly, mm;
Effective length of the leaf spring, mm.
Minimum stress, MPa.
-Stress amplitude, MPa.
Pmin Ln
（10）
（13)
（14）
5.2.2.3 When the test is carried out to 1.0×104, 3.0×104, 6.0×104 and 9.0×104 times, adjust the torque and preload of the tightening bolts to the specified values.
5.2.2.4 The surface temperature of the sample shall not exceed 150℃ during the test. 5.2.2.5 In a leaf spring sample , the number of cycles when any piece of steel plate first appears macro cracks (cracks through the thickness direction on both sides of the same part) is the life of the sample. 5.3 Determination of free arc height
Use general measuring tools to detect when testing performance items. 5.4
Determination of bushing aperture
Use plug gauges for detection.
5.5 Determination of verticality of rolled ears
Use special inspection tools or a combination of general measuring tools for detection. 5 Determination of parallelism and verticality
Use special inspection tools or a combination of general measuring tools for detection. Determination of assembly width
Use a card plate or caliper for detection.
5.8 Determination of rolled ear width
Use a card plate or caliper for detection.
Surface quality inspection
Use visual inspection.
6 Inspection rules
The inspection of leaf springs is divided into factory inspection and type inspection. 74 Permanent deformation and temporary deformation, static arc height, stiffness value d, h., C are calculated according to formula (1), formula (2) and formula (3) respectively: Permanent deformation and temporary deformation:
d=h plus oh
Permanent deformation and temporary deformation, mm;
Where: d
hmo--free arc height before the third loading and unloading, mm; h--free arc height after the third loading and unloading, mm. Static arc height:
hme+he
Where: h static arc height, mm;
h plus e--arc height when the third loading is loaded to the rated load, mm; h.
-arc height when the third unloading is unloaded to the rated load, mm. Stiffness value C (unit Nmm):
C=C++C, +C,+c.
7283—2001
C,, C,, C, in formula (3) are calculated according to formula (4): C
Where: 1=1, 2, 3, 4.
△ P=1.3P,-P,=P-0.7P,:
P—rated load, N;
Deformation corresponding to each △P during loading and unloading, mm, Af
5.1.2.5For leaf spring assemblies with nonlinear characteristics, the stiffness value under a specified load is still measured by the above method using the two-point method and calculated according to formula (5):
Af loading+Af unloading
Where: C refers to the measured stiffness value of a leaf spring under a specified load, Nmm; △P is the difference between the specified load and the reference load, given by the drawing, N: A coffee, Af is the deformation corresponding to each △P during loading and unloading, mm. The bench fatigue life determination
test is carried out on a leaf spring fatigue testing machine. 5.2.1 Support and clamping method
The support method of the spring with ear is shown in Figure 2. The ears are supported on the pulley with rollers by pins, and other structural springs are supported according to the actual installation state on the vehicle or a state similar in function. The middle part is clamped according to the actual installation state on the vehicle or a state similar in function. The clamping must meet the following conditions:
a) The upper and lower clamps are manufactured according to Figure 4, and their dimensions are shown in Table 4. $20
Agricultural trailer
Four-wheel agricultural
Transport vehicle
7C1-7CC3
7CC3-7CC7
Rear and auxiliary
Three-wheel agricultural transport vehicle
Upper clamp
b) See Table 5 for clamping bolts and clamping torque. Vehicle
Agricultural trailer
Four-wheel agricultural
Transport vehicle
7C1.5, 7CC2
7CB2, 7CC3, 7CC4
7CB3, 7CC5-7CC7
0.75t, 1.0
Three-wheel agricultural transport vehicle
5.2.2 Test method
Lower pad
Upper clamping plate
Clamping bolt diameter
Lower pad
Clamping bolt center distance
Before the test, the static deformation F and clamping stiffness C in the clamped state shall be measured. 5.2.2.1
Upper clamp
Lower pad
Clamping torque
98~127
166186
245~294
98~127
127~147
5.2.2.2 During the bench fatigue life test, the pre-deformation and pulsation amplitude are calculated by formula (6) and formula (7): Pre-deformation F (unit: mm):
Fm = 0.6(F + BF
Pulsation amplitude F. (unit: mm):
F=0.4(F, +βJF,
Where: F is the static deformation of the leaf spring under rated load in the clamped state, calculated according to the measured value of the sample under test, cm; β is the spring type coefficient. Agricultural trailer leaf spring: β=2.5; four-wheel agricultural transport vehicle leaf spring: front assembly β=2.5, rear assembly β=2.0, auxiliary spring assembly is based on the main spring assembly: three-wheel agricultural transport vehicle leaf spring: β=2.0. Note: If the limit deformation calculated according to the formula exceeds the maximum allowable stress of the leaf spring material, the test parameters are corrected with the limit deformation corresponding to the maximum stress value. The stress amplitude of the leaf spring is calculated according to formula (8) to formula (14): Fmax =Fm+ F
Where: Fmar
-maximum deflection, mm.
Fmin=Fm-F
Where: Fmin——minimum deflection, mm. 6
Where: Pmc
Where: Pmm
Where: 0m
Where: Onin
Where: 0-
Maximum force, N;
Clamping stiffness of leaf spring, N/mm.
Minimum force, N.
Maximum stress, MPa;
7283-2001
Pmm=FmmC
Pmax Ln
Section modulus of the leaf spring assembly, mm;
Effective length of the leaf spring, mm.
Minimum stress, MPa.
-Stress amplitude, MPa.
Pmin Ln
（10）
（13)
（14）
5.2.2.3 When the test is carried out to 1.0×104, 3.0×104, 6.0×104 and 9.0×104 times, adjust the torque and preload of the tightening bolts to the specified values.
5.2.2.4 The surface temperature of the sample shall not exceed 150℃ during the test. 5.2.2.5 In a leaf spring sample , the number of cycles when any piece of steel plate first appears macro cracks (cracks through the thickness direction on both sides of the same part) is the life of the sample. 5.3 Determination of free arc height
Use general measuring tools to detect when testing performance items. 5.4
Determination of bushing aperture
Use plug gauges for detection.
5.5 Determination of verticality of rolled ears
Use special inspection tools or a combination of general measuring tools for detection. 5 Determination of parallelism and verticality
Use special inspection tools or a combination of general measuring tools for detection. Determination of assembly width
Use a card plate or caliper for detection.
5.8 Determination of rolled ear width
Use a card plate or caliper for detection.
Surface quality inspection
Use visual inspection.
6 Inspection rules
The inspection of leaf springs is divided into factory inspection and type inspection. 72 Test method
Lower plate
Upper clamping plate
Clamping bolt diameter
Lower plate
Clamping bolt center distance
Before the test, the static deformation F and clamping stiffness C in the clamping state are measured. 5.2.2.1
Upper clamp
Lower pad
Clamping torque
98~127
166186
245~294
98~127
127~147
5.2.2.2 During the bench fatigue life test, the pre-deformation and pulsation amplitude are calculated by formula (6) and formula (7): Pre-deformation F (unit: mm):
Fm = 0.6(F + BF
Pulsation amplitude F. (unit: mm):
F=0.4(F, +βJF,
Where: F is the static deformation of the leaf spring under rated load in the clamped state, calculated according to the measured value of the sample under test, cm; β is the spring type coefficient. Agricultural trailer leaf spring: β=2.5; four-wheel agricultural transport vehicle leaf spring: front assembly β=2.5, rear assembly β=2.0, auxiliary spring assembly is based on the main spring assembly: three-wheel agricultural transport vehicle leaf spring: β=2.0. Note: If the limit deformation calculated according to the formula exceeds the maximum allowable stress of the leaf spring material, the test parameters are corrected with the limit deformation corresponding to the maximum stress value. The stress amplitude of the leaf spring is calculated according to formula (8) to formula (14): Fmax =Fm+ F
Where: Fmar
-maximum deflection, mm.
Fmin=Fm-F
Where: Fmin——minimum deflection, mm. 6
Where: Pmc
Where: Pmm
Where: 0m
Where: Onin
Where: 0-
Maximum force, N;
Clamping stiffness of leaf spring, N/mm.
Minimum force, N.
Maximum stress, MPa;
7283-2001
Pmm=FmmC
Pmax Ln
Section modulus of the leaf spring assembly, mm;
Effective length of the leaf spring, mm.
Minimum stress, MPa.
-Stress amplitude, MPa.
Pmin Ln
（10）
（13)
（14）
5.2.2.3 When the test is carried out to 1.0×104, 3.0×104, 6.0×104 and 9.0×104 times, adjust the torque and preload of the tightening bolts to the specified values.
5.2.2.4 The surface temperature of the sample shall not exceed 150℃ during the test. 5.2.2.5 In a leaf spring sample , the number of cycles when any piece of steel plate first appears macro cracks (cracks through the thickness direction on both sides of the same part) is the life of the sample. 5.3 Determination of free arc height
Use general measuring tools to detect when testing performance items. 5.4
Determination of bushing aperture
Use plug gauges for detection.
5.5 Determination of verticality of rolled ears
Use special inspection tools or a combination of general measuring tools for detection. 5 Determination of parallelism and verticality
Use special inspection tools or a combination of general measuring tools for detection. Determination of assembly width
Use a card plate or caliper for detection.
5.8 Determination of rolled ear width
Use a card plate or caliper for detection.
Surface quality inspection
Use visual inspection.
6 Inspection rules
The inspection of leaf springs is divided into factory inspection and type inspection. 72 Test method
Lower plate
Upper clamping plate
Clamping bolt diameter
Lower plate
Clamping bolt center distance
Before the test, the static deformation F and clamping stiffness C in the clamping state are measured. 5.2.2.1
Upper clamp
Lower pad
Clamping torque
98~127
166186
245~294
98~127
127~147
5.2.2.2 During the bench fatigue life test, the pre-deformation and pulsation amplitude are calculated by formula (6) and formula (7): Pre-deformation F (unit: mm):
Fm = 0.6(F + BF
Pulsation amplitude F. (unit: mm):
F=0.4(F, +βJF,
Where: F is the static deformation of the leaf spring under rated load in the clamped state, calculated according to the measured value of the sample under test, cm; β is the spring type coefficient. Agricultural trailer leaf spring: β=2.5; four-wheel agricultural transport vehicle leaf spring: front assembly β=2.5, rear assembly β=2.0, auxiliary spring assembly is based on the main spring assembly: three-wheel agricultural transport vehicle leaf spring: β=2.0. Note: If the limit deformation calculated according to the formula exceeds the maximum allowable stress of the leaf spring material, the test parameters are corrected with the limit deformation corresponding to the maximum stress value. The stress amplitude of the leaf spring is calculated according to formula (8) to formula (14): Fmax =Fm+ F
Where: Fmar
-maximum deflection, mm.
Fmin=Fm-F
Where: Fmin——minimum deflection, mm. 6bzxz.net
Where: Pmc
Where: Pmm
Where: 0m
Where: Onin
Where: 0-
Maximum force, N;
Clamping stiffness of leaf spring, N/mm.
Minimum force, N.
Maximum stress, MPa;
7283-2001
Pmm=FmmC
Pmax Ln
Section modulus of the leaf spring assembly, mm;
Effective length of the leaf spring, mm.
Minimum stress, MPa.
-Stress amplitude, MPa.
Pmin Ln
（10）
（13)
（14）
5.2.2.3 When the test is carried out to 1.0×104, 3.0×104, 6.0×104 and 9.0×104 times, adjust the torque and preload of the tightening bolts to the specified values.
5.2.2.4 The surface temperature of the sample shall not exceed 150℃ during the test. 5.2.2.5 In a leaf spring sample , the number of cycles when any piece of steel plate first appears macro cracks (cracks through the thickness direction on both sides of the same part) is the life of the sample. 5.3 Determination of free arc height
Use general measuring tools to detect when testing performance items. 5.4
Determination of bushing aperture
Use plug gauges for detection.
5.5 Determination of verticality of rolled ears
Use special inspection tools or a combination of general measuring tools for detection. 5 Determination of parallelism and verticality
Use special inspection tools or a combination of general measuring tools for detection. Determination of assembly width
Use a card plate or caliper for detection.
5.8 Determination of rolled ear width
Use a card plate or caliper for detection.
Surface quality inspection
Use visual inspection.
6 Inspection rules
The inspection of leaf springs is divided into factory inspection and type inspection. 7
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