GB/T 8499-1987 Method for determining the center of gravity of earth-moving machinery
Some standard content:
UDC 621.878/879.001.4
National Standard of the People's Republic of China
GB8499-87
ISO5005-1977
Earth-moving machinery
Method for locating the centre of gravity Issued on 1987-12-29
Issued by the State Administration of Standards
Implemented on 1988-07-01
National Standard of the People's Republic of China
Method for locating the centre of gravity of earth-moving machinery
Earth-moving machinery-Method for locating the centre of gravityUDC621.878/879.001.4
GB8499-87
ISO 5005—1977
Machines equipped with working devices or moving parts do not have a fixed center of gravity. When the machine is tilted, the moving parts are offset under the action of gravity, and the liquid and loose parts are displaced, so the center of gravity of the machine changes accordingly. The center of gravity of earth-moving machinery will depend on the position of the working device and auxiliary equipment of the machine. Therefore, when determining the center of gravity, the test conditions must be accurately stated. This standard is equivalent to the international standard ISO5005-1977 <Methods for determining the center of gravity of earth-moving machinery> Subject content and scope of application
This standard specifies the method for determining the center of gravity of earth-moving machinery using a floor scale and a crane. This standard is applicable to the method for determining the center of gravity coordinates of earth-moving machinery such as tractors, loaders, dump trucks and graders when the working device is in any load condition or in any position.
2 Terminology
2.1 Machine: The earth-moving machinery whose center of gravity is to be determined. 2.2 Instruments and equipment: Equipment required to determine the center of gravity of the machine. 2.3 Working device: equipment installed on the machine for special operations (such as bulldozer blades, winches or buckets). 2.4 "Left side" and "right side": refers to the direction of travel when facing the machine. 2.5 Mass: the mass of the machine under test.
Machine preparation and loading
The machine should be kept clean and in normal working condition or tested under the conditions agreed upon by the manufacturer and the test management department. 3.1 The radiator, water tank, hydraulic oil tank and other oil tanks should be filled to the specified working fluid level position, and the fuel tank should be filled or filled to the oil level agreed upon by the manufacturer and the test management department. 3.2 Tools, spare tires, and scattered accessories and equipment should be prepared in accordance with the supply requirements and placed in the specified positions. 3.3 The tire pressure should be inflated according to the manufacturer's instruction manual. If there is an allowable pressure range, it should be inflated according to the recommended maximum pressure. When the machine is equipped with water-filled tires, the liquid should be filled according to the manufacturer's instruction manual. 3.4 The working device should generally be in the normal working position, for example: a. Crawler or tire bulldozers should lower the bulldozer blade to a position slightly off the horizontal reference plane, b. The loader bucket must be fully retracted, the lowest point of the front end of the connecting rod or the bucket must be lowered to a position just slightly off the horizontal reference plane, c. The blade of the grader is in a horizontal position and perpendicular to the horizontal longitudinal axis of the machine, and at the same time 20cm above the horizontal reference plane, and the front wheel rotation plane should be perpendicular to the ground.
The center of gravity coordinates of the machine working device in different positions can be determined by similar methods and recorded in the test report form of Article 6.4. 3.5 Articulated machines are generally tested with the frame locked in a straight line, but this test allows the front and rear frames to be adjusted to the maximum angle or any intermediate angle as required for measurement. 3.6 The size of the marking plate should be a rigid structural member with a height of at least 600mm and a width of 450mm, and it should be attached to the appropriate position of the machine. Its smooth surface for marking should be perpendicular or parallel to the corresponding plane of the machine. Approved by the Ministry of Urban and Rural Construction and Environmental Protection of the People's Republic of China on December 23, 1987 and implemented on July 1, 1988
Measurement method
4.1 Principle
GB8493-87
Use the suspension and ground support reaction method. Measure the ground support reaction when the machine is placed horizontally and tilted longitudinally front and back. Measure and calculate the horizontal distance of the center of gravity from the ground support point at each time, and draw a vertical line of the center of gravity on the marking plate fixed to the machine. The intersection of the three vertical lines indicates the position of the center of gravity. It actually forms a small triangle, and the exact position of the center of gravity should be the intersection of the median lines of the triangle. 4.2 Instruments and equipment
Weighbridge (to be calibrated):
crane,
platform multi
knife edge (rolled angle steel of appropriate size)
level;
square,
marking plate
marking equipment;
j. tape measure.
4.3 Test procedures
Determine the horizontal ordinate, horizontal abscissa and vertical coordinates of the centre of gravity in accordance with the provisions of 4.3.1 to 4.3.3. 4.3.1 Horizontal ordinate (see Figure 1)
Ramp
Figure 1 Determination of the coordinates of the center of gravity
M is the mass of the machine, r is the support reaction force generated by the blade and platform, R+r is the support reaction force generated by the machine, platform and blade at the front blade, R is the support reaction force generated by the machine mass at the front blade; P is the distance between the blades 4.3.1.1 Crawler machinery
Measure the mass of the whole machine M on the scale.
Measure the support reaction force generated by the blade and platform mass. Measure R+r according to Figure 1 and calculate R.
Measure the distance P between the blades and calculate: E=RP/M
Draw a vertical line through the center of gravity on the marking plate fixed to the machine from the calculated value.
（1）
Then make the corresponding reference plane specified in Chapter 5 4.3.1.2 Tire-type machinery
GB8499-87
Tire-type machinery does not need to use a platform and a knife edge. In the non-braking condition, measure the axle load and calculate the value based on the wheelbase. Then make the corresponding reference plane specified in Chapter 5.
4.3.2 Horizontal abscissa (see Figure 2)
Measure the loads R, R, of the left and right tires or tracks, as well as the track gauge or wheelbase b, and calculate the horizontal abscissa of the center of gravity as follows. b
Then make the corresponding reference plane specified in Chapter 5. Note: Due to the height difference between the weighbridge platform and the surrounding ground, the sum of R, R, is usually not necessarily equal to the mass of the machine. The mass M of the machine is determined by the sum of the loads of the left and right tires (tracks). 4.3.3 Vertical coordinate stone of the center of gravity (see Figure 3)
Figure? Determine the horizontal coordinates
R,-left tire or track load, R,-right tire or track load, M-machine mass = R, +Rb-track gauge (wheelbase)
Plane
Figure 3 Determine the vertical coordinates of the center of gravity h
· (2)
M-machine mass, R-support reaction force at the ground point on the scale, d-horizontal distance from the ground point to the element; C-horizontal distance from the center of gravity to the hanging table, A-vertical intersection of the hanging element and the ground, BB\ground contact line, 4.3.3.1 Place one end of the machine to be tested on the scale and lift the other end so that the body makes an angle of 15° to 25° with the horizontal plane (the largest appropriate angle should be used). This method is applicable to tire-type or belt-type machines. The main difference is that the exact position of the ground support reaction force action point, that is, the method of determining the ground contact point is different. The wheels of tire-type machinery are not braked, and the ground contact point is on the vertical line below the bridge axle. Track-type machinery must be adjusted so that the grounding ribs on both sides are on the BB line, or a section of angle iron set on the BB' line is used as the contact line. During the above measurement, the sling should be perpendicular to the horizontal plane in both planes checked with a plumb line. This is a necessary condition to ensure that the ground reaction force in the horizontal direction is zero. 4.3.3.2 Measure the support reaction force R of the machine's grounding point on the scale. 4.3.3.3 Measure the horizontal distance d from the grounding point of the machine to the sling. 4.3.3.4 Calculate the horizontal distance c from the center of gravity to the sling. C=Rd/M
Draw a vertical line through the center of gravity on the marking plate fixed to the machine. Then lift the other end of the machine and repeat the above test. It is not necessary to make the lifting angles at both ends the same. The height of the intersection of the two vertical lines on the marking plate is the vertical coordinate of the center of gravity. Cut the stone according to the corresponding reference surface specified in Chapter 5.
Note that the machine should be driven to the square scale according to the pre-determined chalk line, which will help to draw the plan view of Figure 3. Crawler machines need to be repeatedly tested until their crawler ribs are exactly on the BB' line.
5 Reference surface
5.1 Vertical datum plane 1: It should pass through the drive sprocket shaft of a track-type tractor, but for crawler or wheel loaders, it should pass through the center of the front guide wheel or front axle, as this is an important design datum. 5.2 Vertical datum plane 2: It should pass through the longitudinal main axis of the machine, that is, it is located in the middle of the wheelbase or track gauge. 5.3 Horizontal datum plane: Take the ground plane and the contact surface is rigid, that is, the segment belt reinforcement of crawler machinery shall not cut into the ground. Test result report
6.1 Center of gravity coordinates
To: Horizontal ordinate, which is the distance from the center of gravity to vertical datum plane 1; 3: Transverse coordinate, which is the distance from the center of gravity to vertical datum plane 2, and the center of gravity is positive on the right side of datum plane 2 and negative five on the left side. The vertical coordinate is the height of the center of gravity from the horizontal datum plane. 6.2 The coordinates of the center of gravity should be in millimeters and should be accurate to 10mm. If the datum plane is different from the provisions of Chapter 5, it should be stated. 6.3 All details about the position of the center of gravity of the machine and the position of the working device and the loading shall be reported. 6.4 Test report format
Manufacturer name
Machine type
Engine number
Working device
Test datebzxZ.net
Machine mass M
Working device position
Additional instructions:
Chassis number
Tire pressure: front wheel
Center of gravity coordinates
This standard is under the jurisdiction of the Beijing Construction Machinery Comprehensive Research Institute of the Ministry of Urban and Rural Construction and Environmental Protection. This standard was drafted with the funding of the Changsha Construction Machinery Research Institute of the Ministry of Urban and Rural Construction and Environmental Protection. 4
People's Republic of China
National Standard
Earth-moving machinery
Method for determining the center of gravity
GB8499--87
Published by China Construction Industry Press (Baiwan Village, western suburbs of Beijing) Issued by Xinhua Bookstore Beijing Distribution Office
Supervised by Xinhua Bookstores in various places
18-668
Printed by China Construction Industry Press Printing Factory (Nanlishi Road, Fuwai District, Beijing) Format, 880×1230 mm
Length 1/16 Printing sheet: 1/4 Number of words: 10,000 words
First edition in November 1988
First printing in November 1988
Print run, 11,21D
112·5634
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