Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009 Directives for standardization—Part 1: Structure and drafting of standards.
This standard replaces QC/T 491-1999 Automobile shock absorber—Dimension series and technical conditions and QC/T 545-1999 Automobile shock absorber—Rig testing method. The two standards were combined and the suspension strut was added to form QC/T 491-2018 Automobile shock absorber technique requirements and test methods
With respect to QC/T 491-1999 and QC/T 545-1999, the main changes in this standard are as follows:
——The basic dimensions and parameters of the working cylinders of the telescopic shock absorber with diameters of 25, 27, 32, 35 and 70 series are added to the new standard;
——The basic dimensions and parameters of suspension struts are added to the new standard;
——The old standard only specifies the allowable value of damping force when the piston velocity is 0.52m/s; while the new standard adds the allowable value of damping force when the piston velocity is 0.13m/s, 0.26m/s and above 0.52m/s in addition to 0.52m/s;
——The old standard specifies the size, connection size and piston stroke range of different types of shock absorbers; while the new standard deletes the base length size, connection size and piston stroke;
——The test items such as friction-force of damper, air-force of damper, anti-foam characteristic, dynamic sealing, etc. are added to the new standard;
——The old standard only specifies the force-temperature characteristic requirements at 100 ℃; while the new standard adds the force-temperature characteristic requirements at 80 ℃, -30 ℃, -40 ℃;
——The durability test deletes the single action test method used as the transition method in the old standard, and updates the test times;
——A more relevant test method for road spectrum reliability is added, and it is recommended that qualified suppliers and purchaser conduct tests to accumulate test data.
This standard gives some general technical requirements for automotive shock absorbers. The functions of shock absorbers, especially some accessories and additional functions, such as spring plates, brackets, welded parts, etc., shall be considered in the design of the whole vehicle and performance requirements shall be put forward. These functions vary from vehicle to vehicle and cannot be unified. Therefore, this standard does not provide for them.
This standard was proposed by and is under the jurisdiction of SAC/TC 114 National Technical Committee of Automobile Standardization.
The previous editions of this standard are as follows:
——JB 1459-74;
——JB 1459-85, JB 3901-85;
——QC/T 491-1999, QC/T 545-1999.
Automobile shock absorber technique requirements and test methods
1 Scope
1.1 This standard specifies the technique requirements and test methods of automobile shock absorber.
1.2 This standard is applicable to shock absorbers for M, N and O types of automobile suspension. It may also serve as a reference for shock absorbers for cab suspension and other types of shock absorber components.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 3730.1 Motor vehicles and trailers—Types—Terms and definitions
GB/T 15089 Classification of power-driven vehicles and trailers
QC/T 484 Automobiles—Paint coating
QC/T 572 Rules for cleanliness of automobile—Determination method
3 Terms and definitions
For the purpose of this standard, the following terms and definitions apply.
3.1
telescopic shock absorber
shock absorber composed of the working cylinder and the outer cylinder for oil storage. In the absence of any special statement in this standard, telescopic shock absorber is called as shock absorber for short.
3.2
suspension struts
a telescopic shock absorber that mounted on the suspension to guide and bear a certain lateral force, usually with accessories such as spring plate, bracket, etc. In the absence of any special statement in this standard, suspension struts telescopic shock absorber is called as suspension struts for short.
3.3
stroke
the maximum moving distance that the piston can reach during the use of the shock absorber, which is the difference between the maximum length and the minimum length of the shock absorber.
3.4
force-displacement characteristic
the relationship between the damping force (F) and the test stroke (S) when the two ends of the shock absorber move in relative simple harmonic motion under a certain stroke and frequency. Its curve (F-S) is called indicator diagram.
3.5
ratio of vacant path (δ)
the ratio of the fluctuation length (idle stroke) to the test stroke in the indicator diagram measured at any velocity.
3.6
force-velocity characteristic
the relationship between the damping force (F) and the piston velocity (v) when the two ends of the shock absorber move in relative simple harmonic motion. Its curve (F-v) formed under various velocities is called force-velocity characteristic diagram.
3.7
force-temperature characteristic
the relationship between the damping force (F) measured at different force-temperature and the force-temperature (t) under the same velocity condition. Its curve (F-t) is called force-temperature characteristic diagram.
3.8
friction-force of damper (Ff)
resistance of shock absorber when moving at a velocity not exceeding 5.0 × 10-3m/s
3.9
air-force of damper (Fair)
the force exerted by the air on the piston rod when the piston is in the middle of its stroke as for inflatable shock absorbers
Note: The test position shall be indicated in the results for the air-force of damper not measured at the middle of the stroke.
3.10
anti-foam characteristic
the ability of the force-displacement characteristic to resist the influence of foam.
4 Basic dimensions and parameters
4.1 Diameters of shock absorber working cylinder and piston rod
The diameters of shock absorber working cylinder and piston rod are recommended in Table 1.
Table 1 Diameters of shock absorber working cylinder and piston rod in mm
Working cylinder diameter Piston rod diameter
10 11 12.5 13 15 16 17 18 20 22 25 28
Note: Series A and B in the table are recommended, and Series B is applicable to suspension struts bearing lateral force.
4.2 Type and overall dimension of shock absorber
4.2.1 The basic types of shock absorbers are divided into 5 types, as shown in Figure 1.
Figure 1 Schematic diagram of shock absorber type
Note 1: EE: Ring type at both ends; ES: Upper ring and lower screw type; SE: Lower ring and upper screw type; SS: Screw type at both ends; ST: Strut type.
Note 2: D1: Outer diameter of oil storage cylinder; D2: Outer diameter of dust cover; M: Screw thread
4.2.2 See Table 2 for the maximum outer diameter dimension of shock absorber.
Table 2 The maximum outer diameter dimension of shock absorber in mm.
4.3 Range of rated damping force of shock absorber
The rated damping force of shock absorber usually refers to the resistance at normal temperature [(20 ± 2) ℃, the same below] when the piston speed is 0.52 m/s. When necessary, the manufacturer may negotiate with the user to determine the test conditions to evaluate the shock absorber products. Rated restoring resistance Pr and the rated compression resistance Pc is related to the valve system design. The data listed in Tables 3 and 4 may be used for reference.
Table 3 Range of rated damping force of shock absorber
Diameter of working cylinder /mm Restoring damping force /N Compression damping force /N
Table 4 Range of rated damping force of suspension struts
Diameter of working cylinder /mm Restoring damping force /N Compression damping force /N
5 Performance requirements
5.1 Force-displacement characteristic test
5.1.1 The damping force values at different velocities of the shock absorber shall meet the requirements in Table 5. The recommended indicator test velocities are 0.13m/s, 0.26m/s, 0.52m/s and 1.04m/s respectively. According to the agreement between the supplier and the purchaser, it is also possible to test the force-displacement characteristic at other velocities.
Table 5 Tolerance of damping force of shock absorber at different velocities
Item Piston velocity/(m/s)
Restoring resistance Fr/N
Compression resistance Fc/N
Note: is the rated restoring resistance at the test velocity; is the rated compression resistance at the test velocity.
5.1.2 The indicator diagram of the shock absorber shall be plump and smooth, and there shall be no idle stroke (see Figure 2) and abnormal phenomena. For shock absorbers used in non-passenger cars, the supplier and purchaser may negotiate the size of the idle stroke, but the ratio of vacant path (δ) shall not exceed 5%. δ shall be calculated using the Equation (1):
(1)
5.1.3 The shock absorber shall be free of oil leakage, damage and other phenomena and obvious abnormal noise during force-displacement characteristic test
Figure 2 Schematic diagram for idle stroke of shock absorber
5.2 Friction force test
5.2.1 Without applying lateral force, the friction force Ff measured at the middle point of the stroke of the shock absorber shall meet the limit value specified in Table 6.
Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Basic dimensions and parameters 5 Performance requirements 6 Test method
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009 Directives for standardization—Part 1: Structure and drafting of standards.
This standard replaces QC/T 491-1999 Automobile shock absorber—Dimension series and technical conditions and QC/T 545-1999 Automobile shock absorber—Rig testing method. The two standards were combined and the suspension strut was added to form QC/T 491-2018 Automobile shock absorber technique requirements and test methods
With respect to QC/T 491-1999 and QC/T 545-1999, the main changes in this standard are as follows:
——The basic dimensions and parameters of the working cylinders of the telescopic shock absorber with diameters of 25, 27, 32, 35 and 70 series are added to the new standard;
——The basic dimensions and parameters of suspension struts are added to the new standard;
——The old standard only specifies the allowable value of damping force when the piston velocity is 0.52m/s; while the new standard adds the allowable value of damping force when the piston velocity is 0.13m/s, 0.26m/s and above 0.52m/s in addition to 0.52m/s;
——The old standard specifies the size, connection size and piston stroke range of different types of shock absorbers; while the new standard deletes the base length size, connection size and piston stroke;
——The test items such as friction-force of damper, air-force of damper, anti-foam characteristic, dynamic sealing, etc. are added to the new standard;
——The old standard only specifies the force-temperature characteristic requirements at 100 ℃; while the new standard adds the force-temperature characteristic requirements at 80 ℃, -30 ℃, -40 ℃;
——The durability test deletes the single action test method used as the transition method in the old standard, and updates the test times;
——A more relevant test method for road spectrum reliability is added, and it is recommended that qualified suppliers and purchaser conduct tests to accumulate test data.
This standard gives some general technical requirements for automotive shock absorbers. The functions of shock absorbers, especially some accessories and additional functions, such as spring plates, brackets, welded parts, etc., shall be considered in the design of the whole vehicle and performance requirements shall be put forward. These functions vary from vehicle to vehicle and cannot be unified. Therefore, this standard does not provide for them.
This standard was proposed by and is under the jurisdiction of SAC/TC 114 National Technical Committee of Automobile Standardization.
The previous editions of this standard are as follows:
——JB 1459-74;
——JB 1459-85, JB 3901-85;
——QC/T 491-1999, QC/T 545-1999.
Automobile shock absorber technique requirements and test methods
1 Scope
1.1 This standard specifies the technique requirements and test methods of automobile shock absorber.
1.2 This standard is applicable to shock absorbers for M, N and O types of automobile suspension. It may also serve as a reference for shock absorbers for cab suspension and other types of shock absorber components.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 3730.1 Motor vehicles and trailers—Types—Terms and definitions
GB/T 15089 Classification of power-driven vehicles and trailers
QC/T 484 Automobiles—Paint coating
QC/T 572 Rules for cleanliness of automobile—Determination method
3 Terms and definitions
For the purpose of this standard, the following terms and definitions apply.
3.1
telescopic shock absorber
shock absorber composed of the working cylinder and the outer cylinder for oil storage. In the absence of any special statement in this standard, telescopic shock absorber is called as shock absorber for short.
3.2
suspension struts
a telescopic shock absorber that mounted on the suspension to guide and bear a certain lateral force, usually with accessories such as spring plate, bracket, etc. In the absence of any special statement in this standard, suspension struts telescopic shock absorber is called as suspension struts for short.
3.3
stroke
the maximum moving distance that the piston can reach during the use of the shock absorber, which is the difference between the maximum length and the minimum length of the shock absorber.
3.4
force-displacement characteristic
the relationship between the damping force (F) and the test stroke (S) when the two ends of the shock absorber move in relative simple harmonic motion under a certain stroke and frequency. Its curve (F-S) is called indicator diagram.
3.5
ratio of vacant path (δ)
the ratio of the fluctuation length (idle stroke) to the test stroke in the indicator diagram measured at any velocity.
3.6
force-velocity characteristic
the relationship between the damping force (F) and the piston velocity (v) when the two ends of the shock absorber move in relative simple harmonic motion. Its curve (F-v) formed under various velocities is called force-velocity characteristic diagram.
3.7
force-temperature characteristic
the relationship between the damping force (F) measured at different force-temperature and the force-temperature (t) under the same velocity condition. Its curve (F-t) is called force-temperature characteristic diagram.
3.8
friction-force of damper (Ff)
resistance of shock absorber when moving at a velocity not exceeding 5.0 × 10-3m/s
3.9
air-force of damper (Fair)
the force exerted by the air on the piston rod when the piston is in the middle of its stroke as for inflatable shock absorbers
Note: The test position shall be indicated in the results for the air-force of damper not measured at the middle of the stroke.
3.10
anti-foam characteristic
the ability of the force-displacement characteristic to resist the influence of foam.
4 Basic dimensions and parameters
4.1 Diameters of shock absorber working cylinder and piston rod
The diameters of shock absorber working cylinder and piston rod are recommended in Table 1.
Table 1 Diameters of shock absorber working cylinder and piston rod in mm
Working cylinder diameter Piston rod diameter
10 11 12.5 13 15 16 17 18 20 22 25 28
Note: Series A and B in the table are recommended, and Series B is applicable to suspension struts bearing lateral force.
4.2 Type and overall dimension of shock absorber
4.2.1 The basic types of shock absorbers are divided into 5 types, as shown in Figure 1.
Figure 1 Schematic diagram of shock absorber type
Note 1: EE: Ring type at both ends; ES: Upper ring and lower screw type; SE: Lower ring and upper screw type; SS: Screw type at both ends; ST: Strut type.
Note 2: D1: Outer diameter of oil storage cylinder; D2: Outer diameter of dust cover; M: Screw thread
4.2.2 See Table 2 for the maximum outer diameter dimension of shock absorber.
Table 2 The maximum outer diameter dimension of shock absorber in mm.
Item Working cylinder diameter
20 25 27 30 32 35 40 45 50 65 70
Outside diameter D1 of liquid storage cylinder 34 45 46 46 55 58 63 68 78 88 95
Outer diameter D2 of dust cover 40 54 56 56 67 70 75 83 90 102 110
4.3 Range of rated damping force of shock absorber
The rated damping force of shock absorber usually refers to the resistance at normal temperature [(20 ± 2) ℃, the same below] when the piston speed is 0.52 m/s. When necessary, the manufacturer may negotiate with the user to determine the test conditions to evaluate the shock absorber products. Rated restoring resistance Pr and the rated compression resistance Pc is related to the valve system design. The data listed in Tables 3 and 4 may be used for reference.
Table 3 Range of rated damping force of shock absorber
Diameter of working cylinder /mm Restoring damping force /N Compression damping force /N
Table 4 Range of rated damping force of suspension struts
Diameter of working cylinder /mm Restoring damping force /N Compression damping force /N
5 Performance requirements
5.1 Force-displacement characteristic test
5.1.1 The damping force values at different velocities of the shock absorber shall meet the requirements in Table 5. The recommended indicator test velocities are 0.13m/s, 0.26m/s, 0.52m/s and 1.04m/s respectively. According to the agreement between the supplier and the purchaser, it is also possible to test the force-displacement characteristic at other velocities.
Table 5 Tolerance of damping force of shock absorber at different velocities
Item Piston velocity/(m/s)
Restoring resistance Fr/N
Compression resistance Fc/N
Note: is the rated restoring resistance at the test velocity; is the rated compression resistance at the test velocity.
5.1.2 The indicator diagram of the shock absorber shall be plump and smooth, and there shall be no idle stroke (see Figure 2) and abnormal phenomena. For shock absorbers used in non-passenger cars, the supplier and purchaser may negotiate the size of the idle stroke, but the ratio of vacant path (δ) shall not exceed 5%. δ shall be calculated using the Equation (1):
(1)
5.1.3 The shock absorber shall be free of oil leakage, damage and other phenomena and obvious abnormal noise during force-displacement characteristic test
Figure 2 Schematic diagram for idle stroke of shock absorber
5.2 Friction force test
5.2.1 Without applying lateral force, the friction force Ff measured at the middle point of the stroke of the shock absorber shall meet the limit value specified in Table 6.
Contents of QC/T 491-2018
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Basic dimensions and parameters
5 Performance requirements
6 Test method
