JB/T 7325-1994 Strength test method and acceptance conditions for protective devices of narrow-track wheeled tractors for agriculture and forestry
Some standard content:
Machinery Industry Standard of the People's Republic of China
JB7325-94
Test method and acceptance conditions for strength test of protective devices for narrow-track wheeled tractors for agriculture and forestry
Published on July 18, 1994
Ministry of Machinery Industry of the People's Republic of China
Implementation on July 1, 1995
Subject content and applicable scope
Referenced standards
Test equipment
Test preparation for tractor and protective devices
Preliminary test of front protective devices
Test steps and requirements
Accommodation area
Acceptance conditions
Test report
Appendix A
Test report on strength test of protective devices (reference) Table of Contents|| tt||（10）
（13)
Machinery Industry Standard of the People's Republic of China
Strength test method and acceptance conditions for protective devices of narrow-track wheeled tractors for agriculture and forestry
1 Subject content and scope of application
JB732594
This standard specifies the strength test method and acceptance conditions for protective devices of narrow-track wheeled tractors for agriculture and forestry. This standard is applicable to pneumatic tire tractors with two axles. The ground clearance between the front and rear axles should not be greater than 600mm; the minimum wheelbase of the fixed or adjustable rear wheels should not be greater than 1150mm; the unloaded mass of the tractor (including protective devices and the largest tire provided by the manufacturer) should be greater than 600kg. If it has a front protective device, it should be less than 3000kg at the same time. 2 Reference standards
GB1102
GB7121
JB/T6715bzxz.net
3 Definitions
Wire rope
Strength test method and acceptance conditions for protective devices on agricultural and forestry wheeled tractors Agricultural tractor driver's seat marking points
The terms and definitions used in this standard are the same as those in Chapter 3 of GB7121. 4 Symbols
The symbols used in this standard have the following meanings: R
Reference mass of the connecting tractor, kg;
B, maximum outer width of the protective device, mm;
B-minimum outer corridor width of the tractor, mm; D-
Deformation of the protective device at the impact point (dynamic load) or deformation of the loading point along the loading line (static load), mm: height of the pendulum center of mass, mm;
Static force N;
The maximum load occurring during loading Maximum static load (except overload test), N; force and deformation curve:
Input energy absorbed by lateral loading, J; Input energy absorbed during longitudinal loading, J: Eu
-Vertical compressive force. N
E:-Absorbed strain energy, that is, the area under the FD curve, J;-Reference wheelbase, should not be less than the maximum wheelbase, mm; L
[Reference moment of inertia around the rear axle, excluding the rear wheels, should not be less than the maximum moment of inertia around the rear axle, kg·m. 5 Test equipment
5.1 The device for determining the position of the driver's seat mark point shall comply with the relevant provisions of JB/T6715. Approved by the Ministry of Machinery Industry on July 18, 1994
Implemented on July 1, 1995
JB7325-94
5.2 Device for fixing the tractor: Use wire rope to fix the tractor to the ground rail, which is distributed at a certain distance on the field under the pendulum suspension point. The wire rope should comply with GB1102, with a structure of 6×19: tensile strength of 1700~2000N/mm, and a nominal diameter of 12.5mm.
Other test equipment shall be in accordance with Articles 5.1, 5.3.1, 5.3.3~5.5.3 of GB7121. 6 Preparation for the test of tractors and protective devices
6.1 If the tractor is equipped with an elastic frame, it shall be rigidly fixed during the test. 6.2 The requirements of Articles 6.2.1~6.2.2 shall be met during the impact test. 6.2.1 The tires of the tractor shall not be filled with water and shall be inflated to the normal pressure specified by the manufacturer. 6.2.2 After the steel wire rope fixing the tractor is stretched, the deformation of the tire shall be 12% of the height of the lowest point of the wheel rim from the ground before tensioning. 6.3 Other test preparations shall be carried out in accordance with Articles 6.1 to 6.5, 6.7 and 6.8 of GB7121. 7 Preliminary test of front protective device
The front protective device must pass the preliminary test of Articles 7.1 and 7.2 before the strength test. Before each test, the tractor shall be equipped with protective devices and the tire with the smallest cross section in the largest diameter provided by the manufacturer, and the wheel grease shall be inflated to the normal operating pressure; the rear wheels shall be placed at the narrowest wheel track: the front wheel track shall be as close to that of the rear wheels as possible. If the front wheel track and the narrowest wheel track of the rear wheels are different in size, the wider front wheel track shall be selected; the tractor shall be filled with sufficient oil and water.
7.1 Lateral stability test
The tractor is placed on a horizontal surface, with the steering wheel at the limit position. Appropriate methods (such as using a dry jack or lifting equipment) are used to support the tractor at a position rigidly connected to the axle with a load of more than 50%, so that the tractor is tilted. The tilt angle is continuously measured during the support process. The tilt angle of the tractor when it is unstable and balanced should be greater than 38°. The test is carried out once when the steering wheel is at the left limit position and once when it is at the right limit position. 7.2 Continuous rollover resistance test
7.2.1 Evaluation of continuous rollover resistance performance through rollover test This test is used to test the ability of a tractor equipped with a protective device to prevent continuous lateral rollover on a slope with a slope of 1:1.5 (Figure 1).
Figure 1 Ramp for continuous rollover test of front protective device 2
JB 7325-94
The length of the test ramp should be at least 4m. The surface of the ramp should be covered with a layer of material with a cone index of 235 and a thickness of 18cm. Place the tractor on the top of the ramp with the center line of the tractor parallel to the intersection of the ramp and the top horizontal plane. Turn the tractor downward with a constant initial velocity. The tractor should not roll sideways continuously. 7.2.2 Evaluation of the anti-rollover performance by simulation calculation 7.2.2.1 The parameters of the whole machine required for the simulation calculation are as follows: H, — height of the center of mass, m;
Ls- horizontal distance between the center of mass and the front axle, m
L— horizontal distance between the center of mass and the rear axle, m
D, — height of the upper edge of the front tire from the ground, m:
height of the upper edge of the rear tire from the ground, m;
total height (height of the impact point), M:
cross section of the center of mass and the protective device (through the two Horizontal distance of the vertical plane from the center of the column) (if this cross section is located in front of the center of mass, this value is negative). m:
Width of protective device, m;
Height of the front edge of the engine hood from the ground, m; B, —Width of the engine hood, m:
L, —Horizontal distance between the center of mass and the front angle of the engine hood, m; H.
—Height of the center of the front axle swing pin from the ground, m: —Rear wheel track, m:
B—Rear tire width, m
D. —Front axle swing angle (from zero to the extreme position), rad; in——Tractor mass, kg
I. —Moment of inertia about the longitudinal axis passing through the center of mass, kg·m. 7.2.2.2 The following assumptions are made for the simulation calculation:
The tractor with a balanced front axle is stationary on a ramp of 1!1.5, and its center of mass is directly above the axis of rotation, that is, the axis of rotation is parallel to the longitudinal axis of the tractor and passes through the center of the contact surface between the front and rear wheels and the ramp. The tractor does not slip on the ramp.
The impact of the tractor on the ramp is partially elastic, with an elastic coefficient of 0.2. The sum of the depth of the protective device hitting the ramp and its own deformation at the impact point is 0.2m. Except for the protective device, no other parts enter the ramp. The flowchart of the simulation calculation is shown in Figure 2.
Conclusion:
This method
cannot be used,
Test steps and requirements
8.1 Test items and sequence
JB 7325--94
Input teaching belt
Short B2 type calculation
Jinying Control
Before lowering the protective device,
Whether the engine leather touches the ground
Whether the continuous drawing machine controls the flow
Whether the protective device is installed behind the flat point
I calculate according to B1 type
Whether the human fan drawing machine turns over
Calculate according to B3 type
With the drawing machine Whether to record it newly
Type B1, the impact point is located after the longitudinal unstable balance point Type B2: The impact point is located near the longitudinal unstable balance point Type B3: The impact point is located before the longitudinal unstable balance point Figure 2 Determine the implementation process of the front protective device to resist continuous rollover Dynamic load test items and sequence:
Rear impact test;
Rear pressure span test:
Front impact test:
Side impact test:
Front pressure span test.
Static load test items and sequence:
Rear loading test:
Rear pressure span test:
Front loading test:
Side loading test;
Front pressure span test.
8.2 Test requirements
JB7325-94
8.2.1 The protective equipment and strength test can be selected in the dynamic load test and the static load test. 8.2.2 The impact point or loading force application point of the side impact and the impact point or loading force application point of the rear impact should be on both sides of the weaving center plane of the tractor. The front impact or loading and the side impact or loading are on the same side of the weaving center plane. 8.2.3 During the test, any parts that fix the tractor shall not be damaged or moved, otherwise the test must be repeated. 8.2.4 No parts shall be repaired or corrected between tests. 8.3 Dynamic load test
8.3.1 Rear impact test
The tying method for the rear impact test is shown in Figures 3 and 4. A./100
Lifting the avoidance track of the mass center
Through the impact point
Two steel wires swing
Square wood pad
Figure 3 Front protection device tying method (rear impact) Am/100
A≤204
Two wires increase
Carrying the movement of the mass center
Through the impact point
Two keys continue
Square wood pad
Two wires shoot
Figure 4 Rear protection device tying method (rear impact) 8.3.1.1 Positioning of the tractor
JB7325-94||t t||The tractor shall be fixed in such a position that the pendulum strikes the guard at an angle of m/100 (maximum 20°) to the plumb line when the pendulum strikes the guard. If the guard member is more than m/100 away from the plumb line at the point of maximum deformation (estimated value) at the point of impact, the strike surface may be adjusted by additional support so that the strike surface is parallel to the guard member at the point of impact at maximum deformation, and the pendulum chain bearing chain is still at an angle of m/100 to the plumb line.
8.3.1.2 Position of the point of impact
The point of impact shall be the part of the guard that is most likely to strike the ground first in a rear rollover accident, generally at the top. The center of mass of the pendulum shall be located at 1/6 of the width of the guard from the outer edge. The width of the guard shall be the distance between two parallel planes parallel to the longitudinal center plane of the tractor and passing through the outermost edge of the guard top. If the guard is curved or edged at the impact point, add a mold block without increasing the strength of the guard so that the pendulum can hit the specified position.
8.3.1.3 Fixing of the tractor
The tractor is fixed to the ground with four steel wire ropes. The angle between the steel wire ropes fixing the front axle and the rear axle and the ground should be less than 30. The intersection of the two steel wire ropes of the rear axle should be located in the vertical plane through which the center of mass of the pendulum passes. The requirements for wire rope tensioning are as in Article 6.2.2. After tensioning, the wooden pad is pressed against the front of the rear wheel and fixed to the ground. If the tractor is an articulated tractor, the joint should be firmly fixed to the ground with a wooden block of at least 100 mm square. 8.3.1.4 Pendulum lifting height
For the front-mounted protective device, the pendulum lifting height is calculated by the following formula: H=25+0.07m(m,≤2000kg)
H=125+0.02m(m.>2000kg)
For the rear-mounted protective device, the pendulum lifting height: H=2.165×10mL
8.3.2 Front impact test
For the front impact test, the insertion method is shown in Figures 5 and 6. H=5.73×10~\f
Am/100
A≤20
Understand the movement of the center of mass
Speed passing the impact point
Two steel wires
Method single
Two wire films
Figure 5 Front protective device installation method (front impact) A=m/100
Two key wires
8.3.2.1 Positioning of the tractor
According to Article 8.3.1.1.
8.3.2.2 Location of the impact point
Square wood
JB7325—94
Select the residual engine theft according to the center of mass
Through the law point
Two steel wires
Figure 6 Rear-mounted guard device removal method (front removal) The impact point should be selected at the part of the guard device that is most likely to hit the ground first when the tractor moves forward and rolls over, usually at the top. The center of mass of the pendulum should be located at one-sixth of the width of the guard device from the outer edge to the inside. If the guard device has a curve or flange at the impact point, add a module without increasing the strength of the guard device so that the pendulum can hit this place. 8.3.2.3 Fixing of the tractor
According to Article 8.3.1.3.
8.3.2.4 Pendulum lifting height
Both the front and rear protective devices adopt the following formula: H=25+0.07m
H125+0.02m
8.3.3 Side impact test
The side impact test method is shown in Figure 7.
(m≤2000kg）
(m>2000kg）
Example diagram to ensure contact with the wheel
Stomach root steel wire
Square difference
Figure 7 Protection device tying method (side impact)3 Fixing of tractor
The tractor is fixed to the ground with four steel wire ropes. The angle between the steel wire ropes fixing the front axle and the rear axle and the ground should be less than 30. The intersection of the two steel wire ropes of the rear axle should be located in the vertical plane through which the center of mass of the pendulum passes. The requirements for tensioning the steel wire rope are as in Article 6.2.2. After tensioning, the wooden pad is pressed against the front of the rear wheel and fixed to the ground. If the tractor is an articulated tractor, the joint should be firmly fixed to the ground with a wooden block of at least 100 mm square. 8.3.1.4 Pendulum lifting height
For the front-mounted protective device, the pendulum lifting height is calculated by the following formula: H=25+0.07m(m,≤2000kg)
H=125+0.02m(m.>2000kg)
For the rear-mounted protective device, the pendulum lifting height: H=2.165×10mL
8.3.2 Front impact test
For the front impact test, the insertion method is shown in Figures 5 and 6. H=5.73×10~\f
Am/100
A≤20
Understand the movement of the center of mass
Speed passing the impact point
Two steel wires
Method single
Two wire films
Figure 5 Front protective device installation method (front impact) A=m/100
Two key wires
8.3.2.1 Positioning of the tractor
According to Article 8.3.1.1.
8.3.2.2 Location of the impact point
Square wood
JB7325—94
Select the residual engine theft according to the center of mass
Through the law point
Two steel wires
Figure 6 Rear-mounted guard device removal method (front removal) The impact point should be selected at the part of the guard device that is most likely to hit the ground first when the tractor moves forward and rolls over, usually at the top. The center of mass of the pendulum should be located at one-sixth of the width of the guard device from the outer edge to the inside. If the guard device has a curve or flange at the impact point, add a module without increasing the strength of the guard device so that the pendulum can hit this place. 8.3.2.3 Fixing of the tractor
According to Article 8.3.1.3.
8.3.2.4 Pendulum lifting height
Both the front and rear protective devices adopt the following formula: H=25+0.07m
H125+0.02m
8.3.3 Side impact test
The side impact test method is shown in Figure 7.
(m≤2000kg）
(m>2000kg）
Example diagram to ensure contact with the wheel
Stomach root steel wire
Square difference
Figure 7 Protection device tying method (side impact)3 Fixing of tractor
The tractor is fixed to the ground with four steel wire ropes. The angle between the steel wire ropes fixing the front axle and the rear axle and the ground should be less than 30. The intersection of the two steel wire ropes of the rear axle should be located in the vertical plane through which the center of mass of the pendulum passes. The requirements for tensioning the steel wire rope are as in Article 6.2.2. After tensioning, the wooden pad is pressed against the front of the rear wheel and fixed to the ground. If the tractor is an articulated tractor, the joint should be firmly fixed to the ground with a wooden block of at least 100 mm square. 8.3.1.4 Pendulum lifting height
For the front-mounted protective device, the pendulum lifting height is calculated by the following formula: H=25+0.07m(m,≤2000kg)
H=125+0.02m(m.>2000kg)
For the rear-mounted protective device, the pendulum lifting height: H=2.165×10mL
8.3.2 Front impact test
For the front impact test, the insertion method is shown in Figures 5 and 6. H=5.73×10~\f
Am/100
A≤20
Understand the movement of the center of mass
Speed passing the impact point
Two steel wires
Method single
Two wire films
Figure 5 Front protective device installation method (front impact) A=m/100
Two key wires
8.3.2.1 Positioning of the tractor
According to Article 8.3.1.1.
8.3.2.2 Location of the impact point
Square wood
JB7325—94
Select the residual engine theft according to the center of mass
Through the law point
Two steel wires
Figure 6 Rear-mounted guard device removal method (front removal) The impact point should be selected at the part of the guard device that is most likely to hit the ground first when the tractor moves forward and rolls over, usually at the top. The center of mass of the pendulum should be located at one-sixth of the width of the guard device from the outer edge to the inside. If the guard device has a curve or flange at the impact point, add a module without increasing the strength of the guard device so that the pendulum can hit this place. 8.3.2.3 Fixing of the tractor
According to Article 8.3.1.3.
8.3.2.4 Pendulum lifting height
Both the front and rear protective devices adopt the following formula: H=25+0.07m
H125+0.02m
8.3.3 Side impact test
The side impact test method is shown in Figure 7.
(m≤2000kg）
(m>2000kg）
Example diagram to ensure contact with the wheel
Stomach root steel wire
Square difference
Figure 7 Protection device tying method (side impact)
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