Excavator Slewing Friction Resistance Torque and Slewing Torque Testing Device and Method

Abstract

This invention discloses a testing device for excavator rotational frictional resistance torque and rotational torque, comprising a fixed pulley located above a liftable support column of a fixed pulley, and a force-adding device located above a liftable support column of a force-adding device. The force-adding device includes a motor, a controller, a worm gear reducer, and a rope winding machine; the rope winding machine is connected to a tension gauge via a wire rope. The invention also discloses the usage method of the device, and the testing methods for rotational frictional resistance torque and rotational torque. This invention can perform integrated testing of rotational torque and rotational frictional resistance torque, and can also perform testing when the tension gauge and the bucket rotation direction are not collinear, improving testing accuracy and increasing the utilization rate of the device.

Description

TECHNICAL FIELD

[0001] The present application relates to excavator slewing system test technology, and particularly relates to a slewing friction resistance torque, an excavator slewing torque test device and a test method. BACKGROUND

[0002] During the excavator slewing operation, the slewing torque and the slewing friction resistance torque are important factors affecting the working performance, efficiency and service life of the excavator, and are of great significance to the selection of the slewing motor. At present, the selection of the slewing motor is based on the test results of the circumferential force, the axial force, the radial force, the friction resistance torque between the slewing bearing and the slewing motor, and the overturning torque, etc. before the assembly of the excavator. However, due to the positioning error and the installation error, the slewing torque and the slewing friction resistance torque before and after the assembly are quite different, so it is beneficial to improve the slewing performance of the excavator to calculate and calibrate the slewing torque and the slewing friction resistance torque of the whole machine by using a suitable method.

[0003] The prior art "GB / T 7586-2018 Test methods for hydraulic excavators for earthmoving" proposes a test method for the slewing friction resistance torque of the excavator. However, the friction resistance torque collected at the beginning of the slewing system rotation has large fluctuations, and the calculation method identifies the tangential force as a constant value, resulting in large test errors.

[0004] The prior art CN212621214U proposes an excavator slewing torque test device, which can ensure that the tension meter and the slewing circle of the measured machine model are in the same plane before the test, but still cannot solve the problem that the tension meter and the bucket slewing direction are not collinear during the test. SUMMARY

[0005] The present application provides an excavator slewing friction resistance torque and an excavator slewing torque test device and test method, which can test the slewing torque and the slewing friction resistance torque integrally, can test when the tension meter and the bucket slewing direction are not collinear, improves the test precision, and also improves the utilization rate of the device.

[0006] Technical scheme: The test device of the present application is characterized by comprising a fixed pulley located above a fixed pulley liftable support column and a force adding device located above a force adding device liftable support column; the force adding device comprises a motor, a controller, a worm and gear reducer and a rope winding machine; the rope winding machine is connected with the tension meter through a steel wire rope.

[0007] The rope winding machine is connected with the worm and gear reducer through a bearing, and the end of the bearing is provided with a locker (9).

[0008] The fixed pulley liftable support column and the force adding device liftable support column are located on the base, and the base is connected with external mechanisms through a plurality of bolts passing through the foundation bolt holes.

[0009] The method of using the testing device is characterized by: connecting one end of the tension gauge to the working device via a steel wire rope that passes over a fixed pulley, and connecting the other end to the force-applying device via a steel wire rope; keeping the tension gauge horizontal to measure the tension; controlling the motor to operate via a controller, transmitting power to the rope winding machine via a worm gear reducer; the rope winding machine retracts the steel wire rope, driving the slewing system of the stopped excavator to move.

[0010] A method for testing the slewing frictional resistance torque of an excavator, characterized by the following steps:

[0011] 1) Adjust the excavator's posture: fully retract the boom hydraulic cylinder, fully extend the bucket hydraulic cylinder, and adjust the boom hydraulic cylinder so that the bottom of the bucket is at the height of the boom hydraulic cylinder hinge.

[0012] 2) Install an accelerometer and a gyroscope into the excavator's slewing system. The accelerometer measures the acceleration 'a' of the slewing system, and the gyroscope measures the angle 'θ' of the rotation.

[0013] 3) Before testing, measure the distance r from the working device to the excavator's rotation center, and measure the distance l from the working device to the fixed pulley. The formula for calculating angle t is: Where r is the distance from the working device to the excavator's rotation center, l is the distance from the working device to the fixed pulley, and θ is the angle rotated by the gyroscope test.

[0014] Tangential force F of the working device t Formula 2 for calculation is: F t =Fsin(t-θ), where F is the output pulling force. t The tangential force acting on the working device;

[0015] Based on torque balance, the tangential force F acting on the working device t Transformed into the circumferential force F acting on the center of gravity during rotation c Formula 3 for calculation is: F t r = F c r c , where r c F is the design value for the distance from the center of gravity of the slewing system to the center of rotation of the excavator. c The circumferential force acting on the center of gravity of the rotating system;

[0016] Establish the equation of motion for the rotating system, as shown in Formula 4: F c =Ma+Jα / r c +M r / r c Where M is the mass of the rotating system, a is the acceleration of the rotating system, α is the angular acceleration of the rotating system, α=a / r, and J is the constant moment of inertia of the rotating system;

[0017] 4) At the start of the test, the excavator engine is stopped, the booster motor is started, the motor drives the rope reel to retract the wire rope, and the wire rope drives the slewing system to move. When the slewing system moves smoothly, the slewing friction torque tends to stabilize. During the test, three sets of data are collected respectively. Each set of data is the acceleration a and the rotation angle θ of the corresponding slewing system.

[0018] 5) Solve the equations 1 and 2 simultaneously with the measured rotation angle θ to obtain F. t Using formula 3 and the obtained F t Find F c The acceleration 'a' of the three rotating systems was obtained from the test, and the calculated F was also obtained. c Substituting into Formula 4 and solving the equations simultaneously, we can obtain the rotational friction torque M. r .

[0019] A method for testing the swing torque of an excavator, characterized by comprising the following steps:

[0020] 1) Adjust the excavator's posture: fully retract the boom hydraulic cylinder, fully extend the bucket hydraulic cylinder, and adjust the boom hydraulic cylinder so that the bottom of the bucket is at the height of the boom hydraulic cylinder hinge.

[0021] 2) Turn off the booster and lock the rope winding machine with the locking device to keep the wire rope stationary; turn the excavator to its maximum throttle and rotate it in the opposite direction of the booster. When the rotation system stops moving, the rotation force tends to stabilize.

[0022] 3) Formula 5 for calculating the tangential force angle t′ is: Where r is the distance from the working device to the excavator's slewing center, and l is the distance from the working device to the fixed pulley. The angle rotated during the gyroscope test;

[0023] 4) Tangential force F′ of the working device t Formula 6 for calculation is: Where F is the output pulling force;

[0024] 5) The formula for calculating the rotational torque M is: M = F′ t r.

[0025] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: This invention designs a testing device that can perform integrated testing of rotational torque and rotational frictional resistance torque, improving the utilization rate of the device. This invention establishes the relationship between tangential force and rotational angle, solving the problem of testing even when the force gauge and the bucket's rotation direction are not collinear. Furthermore, when testing the rotational frictional resistance torque, it avoids the problem of large fluctuations in the rotational frictional resistance torque at the beginning of the rotational system by taking the moment of inertia into account, and testing the rotational frictional resistance torque when the speed is stable, reducing test data fluctuations and greatly improving test accuracy. Attached Figure Description

[0026] Figure 1 This is a test posture diagram of the excavator according to the present invention;

[0027] Figure 2 This is a schematic diagram of the principle of the rotary friction resistance torque test of the present invention;

[0028] Figure 3 This is a schematic diagram of the rotational torque testing principle of the present invention;

[0029] Figure 4 This is a schematic diagram of the test device of the present invention.

[0030] In the diagram, 1 is the controller; 2 is the worm gear reducer; 3 is the fixed pulley; 4 is the tension gauge; 5 is the wire rope; 6 is the fixed pulley liftable support column; 7 is the anchor bolt hole; 8 is the force-adding device liftable support column; 9 is the locking device; 10 is the rope winding machine; 11 is the bearing; and 12 is the motor. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0032] The testing apparatus of the present invention, such as Figure 4 The system includes a fixed pulley 3 located above the movable support column 6 and a force-adding device located above the movable support column 8. The force-adding device includes a motor 12, a controller 1, a worm gear reducer 2, and a rope winding machine 10. The rope winding machine 10 is connected to a tension gauge 4 via a wire rope 5. The rope winding machine 10 is connected to the worm gear reducer 2 via a bearing 11, and a locking device 9 is provided at the end of the bearing 11. The movable support column 6 and the movable support column 8 of the force-adding device are located on a base, which is connected to an external mechanism via several bolts passing through anchor bolt holes 7.

[0033] The method of using the testing device of this invention involves connecting one end of a tension gauge 4 to the working device via a steel wire rope 5 that passes over a fixed pulley 3, and the other end to a force-applying device via the same steel wire rope 5. The tension gauge 4 is kept horizontal to measure the tension. The controller 1 controls the motor 12 to operate, transmitting power to the rope winding machine 10 via a worm gear reducer 2. The rope winding machine retracts the steel wire rope 5, driving the slewing system of the stopped excavator. The fixed pulley 3 adjusts the direction of force on the steel wire rope. The support columns 6 and 8 of the fixed pulley and the force-applying device can rise and fall with the excavator's posture, increasing the testing tonnage range of the excavator.

[0034] The present invention provides a method for testing the slewing frictional resistance torque of an excavator, comprising the following steps:

[0035] 1) Adjust the posture of the excavator, the boom hydraulic cylinder is fully retracted, the bucket hydraulic cylinder is fully extended, and the arm hydraulic cylinder is adjusted so that the bucket bottom is at the height of the arm hydraulic cylinder hinge shaft;

[0036] 2) Install the acceleration sensor and the gyroscope to the excavator swing system, the acceleration sensor tests the acceleration a of the swing system, and the gyroscope tests the angle θ turned over;

[0037] 3) As Figure 2 , before testing, measure the distance r of the working device to the center of the excavator swing, measure the distance l of the working device to the fixed pulley, and the calculation formula 1 of the angle t is: Where r is the distance of the working device to the center of the excavator swing, l is the distance of the working device to the fixed pulley, and θ is the angle turned over by the gyroscope test; The tangential force F t of the working device is calculated by formula 2: F t = F sin (t-θ), where F is the output tension, F t is the tangential force on the working device; According to the moment balance, the tangential force F t on the working device is converted into the circumferential force F c on the swing center of gravity, and the calculation formula 3 is: F t r = F c r c , where r c is the designed value of the distance from the center of gravity of the swing system to the center of the excavator swing, and F c is the circumferential force on the center of gravity of the swing system; The motion equation of the swing system is established, and the calculation formula 4 is: F c = Ma + Jα / r c + M r / r c , where M is the mass of the swing system; a is the acceleration of the swing system, α is the angular acceleration of the swing system, α = a / r, and J is the rotational inertia constant value of the swing system;

[0038] 4) Start testing, stop the engine of the excavator, start the motor 12 of the force device, the motor 12 drives the rope winding machine 10 to wind the steel wire rope 5, the steel wire rope 5 drives the swing system to move, when the swing system moves stably, the swing friction torque tends to be stable, and three groups of data are taken respectively during the test, each group of data corresponding to the acceleration a of the swing system and the angle θ turned over;

[0039] 5) Solve F t by simultaneously solving formula 1, formula 2 and the measured angle θ; solve F t by using formula 3 and the obtained F c ; bring the obtained three groups of accelerations a of the swing system and F c into formula 4, and solve to obtain the swing friction torque Mr .

[0040] The present invention provides a method for testing the swing torque of an excavator, comprising the following steps:

[0041] 1) Adjust the excavator's posture: fully retract the boom hydraulic cylinder, fully extend the bucket hydraulic cylinder, and adjust the boom hydraulic cylinder so that the bottom of the bucket is at the height of the boom hydraulic cylinder hinge pin; For example... Figure 2 ;

[0042] 2) Turn off the booster device and lock the rope winding machine 10 with the locking device 9 to keep the wire rope 5 stationary; turn the excavator to its maximum throttle and rotate it in the opposite direction of the booster device. When the rotation system stops moving, the rotation force tends to stabilize.

[0043] 3) such as Figure 3 Formula 5 for calculating the tangential force angle t′ is: Where r is the distance from the working device to the excavator's slewing center, and l is the distance from the working device to the fixed pulley. The angle rotated during the gyroscope test;

[0044] 4) Tangential force F′ of the working device t Formula 6 for calculation is: Where F is the output pulling force;

[0045] 5) The formula for calculating the rotational torque M is: M = F′ t r.

[0046] The existing technology, "GB / T 7586-2018 Test Methods for Hydraulic Excavators for Earthmoving Machinery," proposes a test method for the slewing frictional resistance torque of excavators. However, the frictional resistance torque collected when the slewing system just begins to rotate fluctuates significantly; the calculation method assumes the tangential force to be a constant value, resulting in large test errors.

[0047] To address the problems existing in the prior art, this invention takes the moment of inertia into account when testing the rotary friction resistance torque, thus avoiding the problem of large fluctuations in the rotary friction resistance torque when the rotary system just starts to rotate. The rotary friction resistance torque is tested when the speed is stable, reducing the fluctuation of the test data and greatly improving the test accuracy.

[0048] The existing technology CN212621214U proposes an excavator swing torque testing device, which can ensure that the dynamometer and the swing circle of the tested model are on the same plane before the test, but still does not solve the problem that the dynamometer and the bucket swing direction are not collinear during the test.

[0049] In view of the problems of the prior art, the application establishes the relationship between the tangential force and the rotation angle, and solves the problem that the tension meter and the rotation direction of the bucket are not collinear. Further, the application designs a testing device, which can test the rotation torque and the rotation friction resistance torque integrally, and improves the utilization rate of the device.

Claims

1. A test device, characterized by: It comprises a fixed pulley (3) above a fixed pulley liftable support column (6), a force adding device above a force adding device liftable support column (8); the force adding device comprises a motor (12), a controller (1), a worm and gear reducer (2) and a rope winding machine (10); the rope winding machine (10) is connected with a tension meter (4) through a steel wire rope (5); The application relates to a test method for a rotary friction torque of an excavator, which comprises the following steps: 1) adjusting the posture of the excavator, fully retracting a dipper arm hydraulic cylinder, fully extending a bucket hydraulic cylinder, adjusting a swing arm hydraulic cylinder, and making the bottom of the bucket be at the hinge shaft height of the swing arm hydraulic cylinder; 2) installing an acceleration sensor and a gyroscope on the rotary system of the excavator, testing the acceleration a of the rotary system by the acceleration sensor, and testing the angle theta of rotation by the gyroscope; 3) Before testing, measure the distance r from the working device to the center of rotation of the excavator, measure the distance l from the working device to the fixed pulley, and calculate the angle t according to Formula 1: The tangential force F of the working device t is calculated according to Formula 2: F t = F sin (t - θ), where F is the output tension, F t is the tangential force on the working device; according to the moment balance, the tangential force F t on the working device is converted into the circumferential force F c on the center of gravity of the rotation system, and Formula 3 is: F t r = F c r c , where r c is the designed value of the distance from the center of gravity of the rotation system to the center of rotation of the excavator, and F c is the circumferential force on the center of gravity of the rotation system; the motion equation of the rotation system is established, and Formula 4 is: F c = Ma + Jα / r c + M r / r c , where M is the mass of the rotation system, a is the acceleration of the rotation system, α is the angular acceleration of the rotation system, α = a / r, J is the rotational inertia constant value of the rotation system; 4) starting the test, stopping the engine of the excavator, starting the motor (12) of the force adding device, winding the steel wire rope (5) into the rope winding machine (10) by the motor (12), driving the rotary system to move by the steel wire rope (5), when the rotary system moves stably, the rotary friction torque tends to be stable, and three groups of data are respectively taken during the test, wherein each group of data corresponds to the acceleration a of the rotary system and the angle theta of rotation; 5) Solve for F using equation 1, equation 2, and the measured rotation angle θ t ; Solve for F using equation 3 and the measured rotation angle θ t ; Solve for F using equation 3 and the measured rotation angle θ c ; Substitute the measured acceleration a and the solved F for the three sets of rotating systems into equation 4 c ; Substitute the measured acceleration a and the solved F for the three sets of rotating systems into equation 4 r ; Solve for the frictional resistance moment M of the rotating system using equation 4 2. The test device of claim 1, wherein: The rope winding machine (10) is connected with the worm and gear reducer (2) through a bearing (11), and the end of the bearing (11) is provided with a locker (9).

3. The test device of claim 1, wherein: The fixed pulley liftable support column (6) and the force adding device liftable support column (8) are located on a base, and the base is connected with external mechanisms through a plurality of bolts penetrating through footing bolt holes (7).

4. The method of using a test device of claim 1, wherein: One end of the tension meter (4) is connected with the working device through the steel wire rope (5) winding around the fixed pulley (3), the other end is connected with the force adding device through the steel wire rope (5), the tension meter (4) is kept horizontal, and the tension is measured; the controller (1) controls the operation of the motor (12), power is transmitted to the rope winding machine (10) through the worm and gear reducer (2), the steel wire rope (5) is wound into the rope winding machine, and the rotary system of the stopped excavator is driven to move.

5. A method of testing the slewing torque of an excavator, characterised in that: The application relates to a test method for a rotary friction torque of an excavator, which comprises the following steps: 1) adjusting the posture of the excavator, fully retracting a dipper arm hydraulic cylinder, fully extending a bucket hydraulic cylinder, adjusting a swing arm hydraulic cylinder, and making the bottom of the bucket be at the hinge shaft height of the swing arm hydraulic cylinder; 2) closing the force adding device, locking the rope winding machine (10) by the locker (9) to keep the steel wire rope (5) unmoved; opening the maximum throttle of the excavator, rotating in the opposite direction of the force adding device, and when the rotary system is unmoved, the rotary force tends to be stable; 3) The formula 5 for the tangential force angle t' is: where r is the distance from the working device to the center of rotation of the excavator, l is the distance from the working device to the trolley, is the angle turned by the gyroscope during the test. 4) tangential force F' of the working device t The calculation formula 6 is: where F is the output pull force; 5) The formula 7 for the moment of rotation M is: M = F' t r.

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