JP7376399B2 - Torsion tester - Google Patents

Description

The present invention relates to a torsion testing machine.

Fatigue tests are conducted on test specimens such as shafts and dampers using a torsion testing machine. In this torsion testing machine, for example, a motor is used to alternately and repeatedly apply a torque in a forward rotation direction and a torque in a reverse rotation direction to a test specimen. The torsion testing machine described in Patent Document 1 uses a first speed reducer and a second speed reducer to increase torque from a servo motor and load the test piece with the torque.

Patent No. 5750351

As described above, conventional torsion testing machines use a reduction gear to increase the torque from the motor in order to load a sufficiently large torque onto the test specimen. However, by using a reducer, the gears inside the reducer repeatedly rotate in the forward and reverse directions, resulting in agitation of the cooling oil and heat generation, a decrease in torque transmission efficiency, a decrease in torsional frequency, and torque due to backlash. Problems arise such as a decrease in control accuracy, an increase in the size of the device, or an increase in the noise of the device.

An object of the present invention is to provide a torsion test in which a sufficiently large torque can be applied to a test specimen without using a reduction gear.

In the torsion test according to one aspect of the present invention, torsion torque is applied to the test specimen. This torsion testing machine includes a motor, an input side holding section, and an output side holding section. Torque from the motor is input to the input side holding section. The input-side holding section is configured to hold one end of the test specimen. The output side holding section is configured to hold the other end of the test specimen. The output side holding section is arranged to be rotatable relative to the input side holding section. At least one of the input side holding section and the output side holding section has a damper mechanism. The damper mechanism includes an input member, an output member, and an elastic member. Torque from the motor is input to the input member. The output member is arranged to be rotatable relative to the input member. The elastic member elastically connects the input member and the output member.

According to this configuration, the torque from the motor is applied to the test specimen while compressing the elastic member of the damper mechanism. That is, the torque from the motor is stored as elastic energy in the elastic member of the damper mechanism. Then, when a torque in the reverse rotation direction is applied to the test object next time, not only the torque from this motor but also the torque based on the elastic energy stored in the damper mechanism can be applied to the test object. By repeating this process, more elastic energy can be stored in the damper mechanism. As described above, a sufficient amount of torque can be applied to the test specimen without using a reduction gear.

Preferably, at least one of the input-side holding section and the output-side holding section includes a clutch device that transmits and interrupts torque.

Preferably, the torsion tester further includes a control section that controls the clutch device. The motor alternately and repeatedly outputs torque in the forward rotation direction and torque in the reverse rotation direction. The control unit then controls the clutch device based on the number of repetitions of the motor.

Preferably, the torsion tester further includes an angle sensor that detects the motor torsion angle.

Preferably, the output side holding section is attached to a non-rotatable member.

Preferably, the input side holding section has a mass body. By adjusting the mass of this mass body, the torsion ability of the torsion tester can be improved.

Preferably the motor is a servo motor.

Preferably, the input side holding section includes a torque sensor.

Preferably, the torsion testing machine further includes a torque sensor and a control section. The torque sensor detects the torsional torque applied to the test object. The control unit executes feedback control based on the torsion torque detected by the torque sensor.

Preferably, the torsion testing machine further includes a control section, a torque sensor, and an angle sensor. The torque sensor detects the torsional torque applied to the test object. The angle sensor detects the twist angle of the motor. The control unit executes first feedback control based on the torsion torque detected by the torque sensor and second feedback control based on the torsion angle detected by the angle sensor.

According to the present invention, a sufficient amount of torque can be applied to the test specimen without using a reduction gear.

Schematic diagram of torsion testing machine. FIG. 3 is a sectional view of a damper mechanism and a clutch device. 5 is a flowchart showing a control method of a control unit. A block diagram of a control unit. FIG. 3 is a block diagram of a torque calculation section. A graph showing the torsional characteristics of the damper mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a torsion testing machine according to the present invention will be described with reference to the drawings.

[overall structure]
As shown in FIG. 1, the torsion testing machine 100 is configured to apply torsion torque to the test specimen T. Specifically, the torsion tester 100 is configured to repeatedly apply torsion torque in the forward rotation direction and torsion torque in the reverse rotation direction to the test specimen T. Thereby, the fatigue characteristics of the test specimen T can be evaluated. The torsion tester 100 includes a motor 2, an input side holding section 3, and an output side holding section 4. Further, the torsion testing machine 100 further includes an angle sensor 5 and a control section 6.

[motor]
The motor 2 is configured to output torque to apply a load to the test object T. Specifically, the motor 2 is configured to alternately and repeatedly output torque in the forward rotation direction and torque in the reverse rotation direction. Further, the motor 2 can also repeatedly output only torque in the forward rotation direction or only torque in the reverse rotation direction.

The total number of times the motor 2 outputs torque in the forward rotation direction and the number of times the motor 2 outputs torque in the reverse rotation direction is defined as the number of repetitions of the motor 2. Motor 2 is a servo motor. The twist angle of the torque applied to the test specimen T is, for example, ±50°.

The angle sensor 5 is configured to detect the twist angle (rotation angle) of the motor 2. The angle sensor 5 outputs data regarding the detected twist angle of the motor 2 to the control unit 6.

[Input side holding part]
Torque from the motor 2 is input to the input side holding section 3 . The input-side holding section 3 is configured to hold one end (the left end in FIG. 1) of the test specimen T. That is, the input side holding section 3 is configured to transmit the torque from the motor 2 to the test specimen T. The input side holding section 3 includes a first rotating body 31, a mass body 32, a torque sensor 33, and a first chuck 34.

The first rotating body 31 is arranged so as to be rotated by the torque of the motor 2. The first rotating body 31 is, for example, a shaft. The first rotating body 31 transmits torque from the motor 2 to the test object T.

The mass body 32 is attached to the first rotating body 31 . The mass body 32 is, for example, an annular member. By attaching this mass body 32, the torque applied to the test body T can be increased. This mass 32 can be replaced for torque adjustment. For example, if a larger torque is required, the mass body 32 can be replaced with a larger mass, or if a smaller torque is required, the mass body 32 can be replaced with a smaller mass. Note that the inertia of this mass body 32 is referred to as adjustment inertia.

Torque sensor 33 detects torque acting on first rotating body 31 . The torque sensor 33 outputs data regarding the detected torque to the control unit 6.

The first chuck 34 is attached to the first rotating body 31. The first chuck 34 rotates integrally with the first rotating body 31. The first chuck 34 is configured to hold one end of the test specimen T.

[Output side holding part]
The output-side holding section 4 is configured to hold the other end (the right end in FIG. 1) of the test specimen T. The output side holding part 4 is arranged so as to be rotatable relative to the input side holding part 3. Therefore, torque is applied to the test specimen T held by the input-side holding section 3 and the output-side holding section 4.

The output side holding part 4 is attached to a fixed member 101 that cannot be rotated. Specifically, the output side holding part 4 is attached to the test specimen T at one end in the axial direction, and attached to the non-rotatable fixing member 101 at the other end. That is, the output side holding part 4 is configured so as not to freely rotate.

The output side holding section 4 includes a second rotating body 41, a second chuck 42, a damper mechanism 43, and a clutch device 44.

The second rotating body 41 is rotatably arranged. The second rotating body 41 is rotatably supported by the fixed member 101 via the bearing member 102. The second rotating body 41 is, for example, a shaft. Torque from the motor 2 is transmitted to the second rotating body 41 via the test body T.

The second chuck 42 is attached to the second rotating body 41. The second chuck 42 rotates integrally with the second rotating body 41. The second chuck 42 is configured to hold the other end of the test specimen T.

The damper mechanism 43 is configured to apply torque to the test specimen T by restoring force. As shown in FIG. 2, the damper mechanism 43 includes an input member 431, an output member 432, and a plurality of elastic members 433. As the damper mechanism 43, a known damper mechanism used for a clutch disc, a flywheel, or the like can be adopted.

Torque from the motor 2 is input to the input member 431 . The input member 431 is attached to the second rotating body 41. The input member 431 is fixed to the second rotating body 41 and rotates integrally with the second rotating body 41. For example, the second rotating body 41 is fitted into the input member 431. Note that the input member 431 and the second rotating body 41 may be constituted by one member. That is, the input member 431 may be a part of the second rotating body 41.

The output member 432 is arranged to be rotatable relative to the input member 431. Note that in this embodiment, basically, the output member 432 cannot rotate, and the input member 431 rotates.

The elastic member 433 elastically connects the input member 431 and the output member 432. For example, the elastic member 433 is a coil spring. The input member 431 and the output member 432 each have a plurality of windows extending in the circumferential direction. The window portion of the input member 431 and the window portion of the output member 432 communicate in the axial direction. The windows are arranged at intervals from each other in the circumferential direction. The elastic member 433 is disposed within each window. Therefore, the torque input to the input member 431 is transmitted to the output member 432 via the elastic member 433. The elastic member 433 is compressed by the relative rotation between the input member 431 and the output member 432.

The clutch device 44 transmits and interrupts torque from the motor 2. The clutch device 44 switches between a clutch-on state and a clutch-off state. When the clutch device 44 is in the clutch-on state, torque from the motor 2 is transmitted. On the other hand, when the clutch device 44 is in the clutch-off state, transmission of torque from the motor 2 is cut off.

The clutch device 44 connects the damper mechanism 43 and the fixed member 101. Therefore, the clutch device 44 connects the damper mechanism 43 and the fixing member 101 when the clutch is in the on state. As a result, the damper mechanism 43 becomes unable to rotate. Specifically, the output member 432 of the damper mechanism 43 becomes unrotatable. Note that when the torsion test is being performed, the clutch device 44 is basically in a clutch-on state.

On the other hand, the clutch device 44 releases the connection between the damper mechanism 43 and the fixed member 101 when the clutch is in the off state. As a result, the damper mechanism 43 becomes rotatable. Specifically, the output member 432 of the damper mechanism 43 becomes rotatable. By setting the clutch in the off state in this manner, it becomes possible to rotate the rotor of the motor 2, the input side holding section 3, the test specimen T, and the output side holding section 4 by 360 degrees or more.

Therefore, the oil film of the bearing used in the torsion tester 100 can be prevented from running out. That is, during a torsion test, the bearing is oscillating within a predetermined torsional angle range, so a vibration load is applied to the contact portion, causing an oil film breakage and fretting. On the other hand, the above-mentioned fretting can be prevented by turning the bearing 360 degrees or more in the clutch-off state every predetermined number of repetitions.

The clutch device 44 includes a rotating member 441 and a clutch section 442. Rotating member 441 is rotatably arranged. Specifically, the rotating member 441 is rotatably supported by the fixed member 101 via the bearing member 103. The output member 432 of the damper mechanism 43 is fixed to a rotating member 441. That is, the rotating member 441 of the clutch device 44 and the output member 432 of the damper mechanism 43 rotate integrally.

Clutch section 442 is fixed to fixed member 101. That is, the clutch portion 442 cannot rotate. By operating this clutch portion 442, the rotating member 441 is rendered unrotatable or rotatable. That is, when the clutch portion 442 enters the clutch-on state, the rotating member 441 becomes unable to rotate. On the other hand, when the clutch portion 442 enters the clutch-off state, the rotating member 441 becomes rotatable.

[Control unit]
As shown in FIG. 1, the control unit 6 is configured to control the clutch device 44 based on the number of repetitions of the motor 2. The control unit 6 counts the number of repetitions of the motor 2 based on the data from the angle sensor 5. The control unit 6 then brings the clutch device 44 into the clutch-off state every predetermined number of repetitions.

The control unit 6 is also configured to control the torsion angle and output torque of the motor 2. The control unit 6 includes a CPU (Central Processing Unit), an inverter circuit, a converter circuit, and the like. The control unit 6 can control the output torque and twist angle of the motor 2 by controlling the current. Further, the control unit 6 can control the torsion angle and rotation speed of the motor 2 based on data from the angle sensor 5.

Further, the control unit 6 receives data regarding torque from the torque sensor 33. The control unit 6 can control the twist angle of the motor 2 based on the torque detected by the torque sensor 33.

The control unit 6 executes first feedback control based on the torsional torque detected by the torque sensor 33. Further, the control unit 6 executes second feedback control based on the twist angle detected by the angle sensor 5.

[Control method]
Next, a method of controlling the torsion testing machine 100 by the control unit 6 will be explained. FIG. 3 is a flowchart showing a control method by the control unit 6.

As shown in FIG. 3, first, the control unit 6 drives the motor 2 (step S1). Specifically, the motor 2 is driven so as to alternately and repeatedly output torque in the forward rotation direction and torque in the reverse rotation direction. At this time, the clutch device 44 is in a clutch-on state.

Then, the control unit 6 counts the number of repetitions of the motor 2 (step S2). Specifically, the control unit 6 counts the number of repetitions of the motor 2 based on data from the angle sensor 5.

Next, the control unit 6 determines whether the number of repetitions of the motor 2 has reached a predetermined value (step S3). When the control unit 6 determines that the number of repetitions has not reached the predetermined value (No in step S3), the process returns to step S1 described above.

On the other hand, when the control unit 6 determines that the number of repetitions has reached the predetermined value (Yes in step S3), it controls the clutch device 44 to put the clutch device 44 in a clutch-off state (step S4). Then, the control unit 6 rotates the motor 2 one or more revolutions (step S5). That is, the control unit 6 rotates the motor 2 by 360 degrees or more. Note that the direction in which the motor 2 is rotated may be a forward rotation direction or a reverse rotation direction.

As described above, by rotating the motor 2 by 360 degrees or more, it becomes possible to rotate the input side holding part 3, the test specimen T, and the output side holding part 4 by 360 degrees or more. Therefore, the oil film of the bearing used in the torsion tester 100 can be prevented from running out.

Next, the control unit 6 controls the clutch device 44 to turn the clutch device 44 into a clutch-on state (step S6). Then, the control unit 6 resets the count number and returns to the process of step S1.

Next, feedback control by the control section 6 when driving the motor 2 will be explained.

As shown in FIG. 4, the control unit 6 receives a torsion torque command value in the forward rotation direction, a torsion torque command value in the reverse rotation direction, and a torsion frequency command value ω. Further, the current torque value detected by the torque sensor 33 and the current torsion angle value detected by the angle sensor 5 are input to the control unit 6 .

The control unit 6 executes first feedback control based on the current torque value detected by the torque sensor 33, and generates a torsion angle command value A. For example, the twist angle command value A can be expressed by the following equation (1).
A=αsin(ωt)-β...(1)
Note that α is the twist angle width (amplitude), t is time, and β is an offset value.

Further, the control unit 6 executes second feedback control based on the current value of the torsion angle detected by the angle sensor 5 , generates a torque command value, and outputs it to the motor 2 .

In detail, the control section 6 includes a maximum torsion torque calculation section 61, a first torsion torque error calculation section 62, a torsion angle width calculation section 63, a minimum torsion torque calculation section 64, a second torque error calculation section 65, and a torsion angle offset calculation section. It has a calculation section 66, a torsion angle command value generation section 67, a torsion angle error calculation section 68, and a torsion torque calculation section 69.

The maximum torsion torque calculation unit 61 calculates the maximum torsion torque in one cycle based on the data from the torque sensor 33. The first torsion torque error calculation unit 62 calculates the error between the input torsion torque command value in the forward rotation direction and the maximum torsion torque calculated by the maximum torsion torque calculation unit 61.

The torsion angle width calculation unit 63 calculates the torsion angle width α based on the error calculated by the first torsion torque error calculation unit 62. For example, when the maximum torsion torque is smaller than the command value, the torsion angle width calculating section 63 calculates a larger torsion angle width α. Further, when the maximum torsion torque is larger than the command value, the torsion angle width calculating section 63 calculates a smaller torsion angle width α.

The minimum torsion torque calculation unit 64 calculates the minimum torsion torque during one cycle based on the data from the torque sensor 33. The second torque error calculation unit 65 calculates the error between the input torsion torque command value in the reverse rotation direction and the minimum torsion torque calculated by the minimum torsion torque calculation unit 64.

The torsion angle offset calculation unit 66 calculates the offset value β based on the error calculated by the second torque error calculation unit 65. For example, when the minimum torsion torque is smaller than the command value, the torsion angle offset calculation unit 66 calculates a larger offset value β. Further, when the minimum torsion torque is larger than the command value, the torsion angle offset calculation unit 66 calculates a smaller offset value β.

The torsion angle command value generation unit 67 generates a torsion angle command based on the torsion angle width α calculated by the torsion angle width calculation unit 63, the offset value β calculated by the torsion angle offset calculation unit 66, and the torsion frequency command value ω. Generate value A. For example, a torsion angle command value A as shown in the above equation (1) is generated. Note that the torsion angle command value A shown in equation (1) is an example, and is not limited to a sine wave.

Next, the torsion angle error calculation unit 68 calculates the difference between the current torsion angle value detected by the angle sensor 5 and the torsion angle command value A generated by the torsion angle command value generation unit 67 as an angle error.

The torsion torque calculation unit 69 calculates the angle error calculated by the torsion angle error calculation unit 68, the current value of the torsion angle detected by the angle sensor 5, the torsion characteristic correction torque of the damper mechanism 43, and the characteristic of the torsion tester 100. Based on the inertia and the adjustment inertia of the mass body 32, a torque command value is generated and output to the motor 2.

As shown in FIG. 5, the torsion torque calculation section 69 includes an angle control section 691, an angular velocity control section 692, an angular acceleration control section 693, and a torque command value generation section 694.

The angle control unit 691 obtains the angle error calculated by the twist angle error calculation unit 68. The angular velocity control unit 692 calculates the difference between the angular velocity command value calculated by differentiating the angular error acquired by the angle control unit 691 and the angular velocity current value calculated by differentiating the torsion angle current value detected by the angle sensor 5. is calculated as the angular velocity difference.

The angular acceleration control unit 693 calculates the angular acceleration by differentiating the angular acceleration command value calculated by differentiating the angular velocity difference calculated by the angular velocity control unit 692 and the torsion angle current value detected by the angle sensor 5 twice. The difference between the current value and the current value is calculated as the angular acceleration difference.

The torque command value generation unit 694 calculates the acceleration steady-state deviation control torque calculated from the angular acceleration difference calculated by the angular acceleration control unit 693, the torsion characteristic correction torque of the damper mechanism 43, the inherent inertia, and the adjustment inertia. A torque command value is generated by combining the inertia correction torque and the inertia correction torque.

Specifically, first, the torque command value generation unit 694 calculates the acceleration steady-state deviation control torque based on the angular acceleration difference calculated by the angular acceleration control unit 693. Specifically, the torque command value generation unit 694 calculates the acceleration steady-state deviation control torque by performing PID control based on the angular acceleration difference.

Further, the torque command value generation unit 694 calculates the torsion characteristic correction torque of the damper mechanism 43. Specifically, the torque command value generation unit 694 calculates the torsion characteristic correction torque of the damper mechanism 43 based on the torsion angle command value. For example, the torque command value generation unit 694 has a torsion characteristic map as shown in FIG. Then, the torque command value generation unit 694 calculates a torsion characteristic correction torque corresponding to the torsion angle command value based on this torsion characteristic map.

Further, the torque command value generation unit 694 calculates an inertia correction torque. Specifically, the torque command value generation unit 694 calculates the inertia correction torque based on the inherent inertia of the torsion testing machine 100 and the adjustment inertia of the mass body 32. For example, the torque command value generation unit 694 calculates the inertia correction torque by multiplying the inertia, which is a combination of the specific inertia and the adjustment inertia, by the angular acceleration command value calculated by the angular acceleration control unit 693. Can be done. Note that the specific inertia is the inertia of the torsion testing machine 100 excluding the mass body 32.

[Features]
The torsion tester 100 configured as described above can apply a torsion torque greater than the output torque of the motor 2 to the test body T, as described below. First, the motor 2 outputs torque in the forward rotation direction, and the torque is applied to the test specimen T. At this time, the damper mechanism 43 is twisted by a twisting angle θ1 due to the output torque of the motor 2. Therefore, elastic energy is stored in the elastic member 433 of the damper mechanism 43. Next, the motor 2 outputs torque in the reverse rotation direction. Here, since there is elastic energy accumulated in the elastic member 433 in addition to the output energy of the motor 2, a torque based on the output energy of the motor 2 and the elastic energy of the elastic member 433 is loaded on the test specimen T in the reverse rotation direction. Ru. Further, the output energy of the motor 2 and the elastic energy of the elastic member 433 are stored in the elastic member 433 as elastic energy. This process is repeated, the twist angle gradually increases, and a twist torque greater than the output torque of the motor 2 is generated.

[Modified example]
Although the embodiments of the present invention have been described above, the present invention is not limited to these, and various changes can be made without departing from the spirit of the present invention.

Modification example 1
In the above embodiment, the output side holding section 4 had the damper mechanism 43, but the input side holding section 3 may have the damper mechanism 43.

Modification example 2
In the embodiment described above, the output side holding section 4 has the clutch device 44, but the input side holding section 3 may have the clutch device 44.

100 Torsion tester 2 Motor 3 Input side holding part 32 Mass body 33 Torque sensor 4 Output side holding part 43 Damper mechanism 431 Input member 432 Output member 433 Elastic member 44 Clutch device 5 Angle sensor 6 Control part

Claims (10)

A torsion testing machine that applies torsional torque to a test specimen,
motor and
an input-side holding section configured to receive torque from the motor and hold one end of the test specimen;
an output-side holding part configured to hold the other end of the test specimen and arranged to be rotatable relative to the input-side holding part;
Equipped with
At least one of the input side holding part and the output side holding part has a damper mechanism,
The damper mechanism includes an input member into which torque from the motor is input, an output member arranged to be rotatable relative to the input member, and an elastic member elastically connecting the input member and the output member. , has
Torsion tester.
At least one of the input-side holding section and the output-side holding section has a clutch device that transmits and interrupts torque.
The torsion testing machine according to claim 1.
further comprising a control unit that controls the clutch device,
The motor alternately and repeatedly outputs torque in the forward rotation direction and torque in the reverse rotation direction,
The control unit controls the clutch device based on the number of repetitions of the motor.
The torsion testing machine according to claim 2.
further comprising an angle sensor that detects a torsion angle of the motor;
A torsion testing machine according to any one of claims 1 to 3.
The output side holding part is attached to a non-rotatable member,
A torsion testing machine according to any one of claims 1 to 4.
The input side holding section has a mass body,
A torsion testing machine according to any one of claims 1 to 5.
the motor is a servo motor;
Torsion testing machine according to any one of claims 1 to 6.
The input side holding section has a torque sensor,
A torsion testing machine according to any one of claims 1 to 7.
a torque sensor that detects torsional torque applied to the test specimen;
a control unit that executes feedback control based on the torsional torque detected by the torque sensor;
further comprising,
The torsion testing machine according to claim 1.
a control unit;
a torque sensor that detects torsional torque applied to the test specimen;
an angle sensor that detects the torsion angle of the motor;
Furthermore,
The control unit executes first feedback control based on the torsion torque detected by the torque sensor and second feedback control based on the torsion angle detected by the angle sensor.
The torsion testing machine according to claim 1.

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