Device and method for testing rotation friction resistance moment and rotation moment of excavator
Technical Field
The invention relates to a technology for testing an excavator rotation system, in particular to a device and a method for testing rotation friction resistance moment and rotation moment of an excavator.
Background
In the process of the rotation operation of the excavator, the rotation moment and the rotation friction resistance moment are important factors influencing the working performance, the efficiency and the service life of the excavator, and have important significance for the selection of the rotation motor. At present, the rotary motor is selected based on circumferential force, axial force and radial force obtained by testing, friction resistance moment and overturning moment between the rotary motor and a slewing bearing before the excavator is assembled. However, due to positioning errors and installation errors, the difference between the rotation moment and the rotation friction resistance moment before and after assembly is larger, so that the rotation moment and the rotation friction resistance moment of the whole excavator are calculated and calibrated by adopting a proper method, and the rotation performance of the excavator is improved.
The prior art GB/T7586-2018 test method for the hydraulic excavator of the earthmoving machinery provides a test method for the rotation friction resistance moment of the excavator. However, the friction resistance moment when the rotary system just starts to rotate is collected, and the fluctuation is large; the calculation method recognizes the tangential force as a fixed value, resulting in a larger test error.
The prior art CN212621214U provides a rotation moment testing device for an excavator, which can ensure that a tension meter and a tested machine type rotation circle are on the same plane before testing, but still does not solve the problem that the tension meter and the bucket rotation direction are not collinear in the testing process.
Disclosure of Invention
The invention aims to: aiming at the defects and shortcomings of the prior art, the invention provides the device and the method for testing the rotation friction resistance moment of the excavator, which can be used for integrally testing the rotation moment and the rotation friction resistance moment of the excavator, and can be used for testing when a tension meter and the rotation direction of a bucket are not collinear, so that the testing precision is improved, and the utilization rate of the device is also improved.
The technical scheme is as follows: the invention relates to a testing device, which is characterized in that: comprises a fixed pulley positioned above a fixed pulley liftable support column and a force application device positioned above the force application device liftable support column; the stress application device comprises a motor, a controller, a worm gear reducer and a rope winding machine; the rope winding machine is connected with the tension meter through a steel wire rope.
The rope winding machine is connected with the worm gear reducer through a bearing, and a locker (9) is arranged at the end part of the bearing.
The fixed pulley lifting support column and the stressing device lifting support column are positioned on the base, and the base is connected with an external mechanism through a plurality of bolts penetrating through the foundation bolt holes.
The using method of the testing device is characterized in that: one end of the tension meter is connected with the working device through a steel wire rope which bypasses the fixed pulley, and the other end of the tension meter is connected with the stress application device through the steel wire rope, and the tension meter is kept horizontal, so that tension is measured; the controller controls the motor to run, and transmits power to the rope winding machine through the worm gear reducer, and the rope winding machine receives the steel wire rope and drives the stopped excavator revolving system to move.
The method for testing the rotation friction resistance moment of the excavator is characterized by comprising the following steps of: comprising the following steps:
1) Adjusting the posture of the excavator, fully shrinking the bucket rod hydraulic cylinder, fully extending the bucket hydraulic cylinder, and adjusting the movable arm hydraulic cylinder to enable the bucket bottom to be positioned at the hinged shaft height of the movable arm hydraulic cylinder;
2) Installing an acceleration sensor and a gyroscope to the excavator rotating system, wherein the acceleration sensor tests the acceleration a of the rotating system, and the gyroscope tests the rotated angle theta;
3) Before testing, measuring the distance r from the working device to the rotation center of the excavator, measuring the distance l from the working device to the fixed pulley, and calculating an angle t according to a formula 1:
wherein r is the distance from the working device to the rotation center of the excavator, l is the distance from the working device to the fixed pulley, and θ is the angle through which the gyroscope test is performed;
tangential force F of working device t The calculation formula 2 of (2) is: f (F) t Fsin (t- θ), where F is the output tension, F t Tangential forces to which the working device is subjected;
according to the moment balance, the tangential force F born by the working device t Is converted into a circumferential force F applied by the center of gravity of rotation c The calculation formula 3 of (2) is: f (F) t r=F c r c Wherein r is c Is a rotary systemDesign value of distance from center of gravity to rotation center of excavator, F c Circumferential force applied to the center of gravity of the rotary system;
establishing a motion equation of a rotary system, wherein the motion equation is calculated as formula 4: f (F) c =Ma+Jα/r c +M r /r c Wherein M is the mass of the gyratory system, a is the acceleration of the gyratory system, α is the angular acceleration of the gyratory system, α=a/r, J is the moment of inertia constant of the gyratory system;
4) The method comprises the steps that a test is started, an engine of the excavator is stopped, a motor of a force application device is started, the motor drives a rope winding machine to collect a steel wire rope, the steel wire rope drives a rotary system to move, when the rotary system moves stably, rotary friction resistance moment tends to be stable, three groups of data are respectively taken in the test process, and each group of data is acceleration a and a rotation angle theta of the corresponding rotary system;
5) Simultaneous equations 1, 2 and measured rotation angle θ to obtain F t The method comprises the steps of carrying out a first treatment on the surface of the Using equation 3 and F t Obtaining F c The method comprises the steps of carrying out a first treatment on the surface of the The acceleration a and the obtained F of the three groups of rotary systems are obtained by testing c Carrying out formula 4, and solving in parallel to obtain rotary friction resistance moment M r 。
The method for testing the rotation moment of the excavator is characterized by comprising the following steps of: comprising the following steps:
1) Adjusting the posture of the excavator, fully shrinking the bucket rod hydraulic cylinder, fully extending the bucket hydraulic cylinder, and adjusting the movable arm hydraulic cylinder to enable the bucket bottom to be positioned at the hinged shaft height of the movable arm hydraulic cylinder;
2) Closing the force application device, and locking the rope winding machine by the locker to keep the steel wire rope motionless; opening the maximum throttle of the excavator, and rotating in the opposite direction of the force application device, wherein when the rotation system is not moving, the rotation force tends to be stable;
3) The
calculation formula 5 of the tangential force angle t' is:
wherein r is the distance from the working device to the rotation center of the excavator, l is the distance from the working device to the fixed pulley,/and a few degrees>
The angle of rotation for the gyroscope test;
4) Tangential force F 'of the working device'
t The
calculation formula 6 of (2) is:
wherein F is the output tension;
5) The calculation formula 7 of the turning moment M is: m=f' t r。
The beneficial effects are that: compared with the prior art, the invention has the following remarkable advantages: the invention designs the testing device, which can integrally test the rotation moment and the rotation friction resistance moment, and improves the utilization rate of the device. The invention establishes the relationship between the tangential force and the rotation angle, and solves the problem that the tension meter can be tested when the rotation direction of the tension meter and the rotation direction of the bucket are not collinear. In addition, when the rotary friction resistance moment is tested, the problem that the rotary friction resistance moment is large in fluctuation when the rotary system just starts to rotate is avoided, the moment of inertia is taken into consideration, the rotary friction resistance moment is tested when the speed is stable, the fluctuation of test data is reduced, and the test precision is greatly improved.
Drawings
FIG. 1 is a test attitude diagram of an excavator according to the present invention;
FIG. 2 is a schematic diagram of a rotational friction drag torque test of the present invention;
FIG. 3 is a schematic diagram of a swing torque test of the present invention;
fig. 4 is a schematic structural diagram of the testing device of the present invention.
In the figure, 1 is a controller; 2 is a worm gear reducer; 3 is a fixed pulley; 4 is a tension meter; 5 is a steel wire rope; 6 is a fixed pulley liftable support column; 7 is a foundation bolt hole; 8 is a lifting support column of the stress application device; 9 is a locker; 10 is a rope winder; 11 is a bearing; 12 is an electric motor.
Detailed Description
The technical scheme of the invention is further described below with reference to the accompanying drawings and the specific embodiments.
The testing device of the invention, as shown in figure 4, comprises a fixed pulley 3 positioned above a fixed pulley liftable support column 6 and a force application device positioned above a force application device liftable support column 8; the force application device comprises a motor 12, a controller 1, a worm gear reducer 2 and a rope winding machine 10; the rope winder 10 is connected with the tension meter 4 through a wire rope 5. The rope winding machine 10 is connected with the worm gear reducer 2 through a bearing 11, and a locker 9 is arranged at the end part of the bearing 11. The fixed pulley liftable support column 6 and the stressing device liftable support column 8 are positioned on a base, and the base is connected with an external mechanism through a plurality of bolts penetrating through the foundation bolt holes 7.
According to the application method of the testing device, one end of the tension meter 4 is connected with the working device through the steel wire rope 5 which bypasses the fixed pulley 3, the other end of the tension meter 4 is connected with the stress application device through the steel wire rope 5, and the tension meter 4 is kept horizontal, so that tension is measured; the controller 1 controls the motor 12 to operate, and transmits power to the rope winding machine 10 through the worm gear reducer 2, and the rope winding machine receives the steel wire rope 5 and drives the stopped excavator revolving system to move. The fixed pulley 3 adjusts the stress direction of the steel wire rope, and the support columns 6 and 8 of the fixed pulley and the stress application device can be lifted along with the posture of the excavator, so that the test tonnage range of the excavator is improved.
The invention relates to a method for testing the rotation friction resistance moment of an excavator, which comprises the following steps:
1) Adjusting the posture of the excavator, fully shrinking the bucket rod hydraulic cylinder, fully extending the bucket hydraulic cylinder, and adjusting the movable arm hydraulic cylinder to enable the bucket bottom to be positioned at the hinged shaft height of the movable arm hydraulic cylinder;
2) Installing an acceleration sensor and a gyroscope to the excavator rotating system, wherein the acceleration sensor tests the acceleration a of the rotating system, and the gyroscope tests the rotated angle theta;
3) As shown in fig. 2, before testing, the distance r from the working device to the rotation center of the excavator is measured, the distance l from the working device to the fixed pulley is measured, and the
calculation formula 1 of the angle t is as follows:
wherein r is the distance from the working device to the rotation center of the excavator, l is the distance from the working device to the fixed pulley, and θ is the angle through which the gyroscope test is performed; tangential force F of working device
t The
calculation formula 2 of (2) is: f (F)
t =fsin (t- θ), where F is the output tension,F
t tangential forces to which the working device is subjected; according to the moment balance, the tangential force F born by the working device
t Is converted into a circumferential force F applied by the center of gravity of rotation
c The
calculation formula 3 of (2) is: f (F)
t r=F
c r
c Wherein r is
c F is a design value of the distance from the center of gravity of the swing system to the swing center of the excavator
c Circumferential force applied to the center of gravity of the rotary system; establishing a motion equation of a rotary system, wherein the motion equation is calculated as formula 4: f (F)
c =Ma+Jα/r
c +M
r /r
c Wherein M is the mass of the gyratory system; a is acceleration of the rotary system, alpha is angular acceleration of the rotary system, alpha=a/r, and J is a fixed value of rotational inertia of the rotary system;
4) Starting a test, stopping an engine of the excavator, starting a motor 12 of a force application device, driving a rope winding machine 10 to collect a steel wire rope 5 by the motor 12, driving a rotary system to move by the steel wire rope 5, and respectively taking three groups of data in the test process when the rotary system moves stably and the rotary friction resistance moment tends to be stable, wherein each group of data is the acceleration a and the rotated angle theta of the corresponding rotary system;
5) Simultaneous equations 1, 2 and measured rotation angle θ to obtain F t The method comprises the steps of carrying out a first treatment on the surface of the Using equation 3 and F t Obtaining F c The method comprises the steps of carrying out a first treatment on the surface of the The acceleration a and the obtained F of the three groups of rotary systems are obtained by testing c Carrying out formula 4, and solving in parallel to obtain rotary friction resistance moment M r 。
The invention relates to a method for testing the rotation moment of an excavator, which comprises the following steps:
1) Adjusting the posture of the excavator, fully shrinking the bucket rod hydraulic cylinder, fully extending the bucket hydraulic cylinder, and adjusting the movable arm hydraulic cylinder to enable the bucket bottom to be positioned at the hinged shaft height of the movable arm hydraulic cylinder; as in fig. 2;
2) Closing the force application device, and locking the rope reel 10 by the locker 9 to keep the steel wire rope 5 motionless; opening the maximum throttle of the excavator, and rotating in the opposite direction of the force application device, wherein when the rotation system is not moving, the rotation force tends to be stable;
3) As shown in fig. 3, the
calculation formula 5 of the tangential force angle t' is:
wherein r is the distance from the working device to the rotation center of the excavator, l is the distance from the working device to the fixed pulley,/and a few degrees>
The angle of rotation for the gyroscope test;
4) Tangential force F 'of the working device'
t The
calculation formula 6 of (2) is:
wherein F is the output tension;
5) The calculation formula 7 of the turning moment M is: m=f' t r。
The prior art GB/T7586-2018 test method for the hydraulic excavator of the earthmoving machinery provides a test method for the rotation friction resistance moment of the excavator. However, the friction resistance moment when the rotary system just starts to rotate is collected, and the fluctuation is large; the calculation method recognizes the tangential force as a fixed value, resulting in a larger test error.
According to the invention, the moment of inertia is taken into consideration when the moment of rotation friction resistance is tested, so that the problem that the moment of rotation friction resistance fluctuates greatly when the rotation system just starts to rotate is avoided, the moment of rotation friction resistance is tested when the speed is stable, the fluctuation of test data is reduced, and the test precision is greatly improved.
The prior art CN212621214U provides a rotation moment testing device for an excavator, which can ensure that a tension meter and a tested machine type rotation circle are on the same plane before testing, but still does not solve the problem that the tension meter and the bucket rotation direction are not collinear in the testing process.
Aiming at the problems in the prior art, the invention establishes the relationship between the tangential force and the rotation angle, and solves the problem that the tension meter and the bucket rotation direction can be tested when the tension meter and the bucket rotation direction are not collinear. Furthermore, the invention designs the testing device, which can integrally test the rotation moment and the rotation friction resistance moment, thereby improving the utilization rate of the device.