JP7078377B2 - Vibration generator - Google Patents

Description

The present invention relates to a vibration generator, and more particularly to a vibration generator that utilizes a functional fluid whose viscoelasticity changes in response to the application of an electric field or a magnetic field.

For example, the muscle strength training / evaluation device of Patent Document 1 uses a movable body that operates by the operation input of a muscle strength trainer and a magnetic viscous fluid that changes its viscosity according to the strength of a magnetic field to load the movement of the movable body. Shows to give. Further, the ferrofluid is arranged in a variable magnetic field, a sensor unit for detecting the load is provided, and the load is controlled according to the output of the sensor.

The strength training device of Patent Document 2 shows a technique for variably presenting a combination of load strength or load mode even during the operation of a trainer. Specifically, a movable body that rotates in conjunction with the rotation of the operation unit, a movable body that is rotated by the rotation drive body, and a second movable body to the first movable body due to the viscosity that changes according to the strength of the electric field. It is equipped with an electrorheological fluid that transmits torque to the body side, a sensor unit that detects the load applied to the operation unit, and a sensor unit that detects the rotation angle of the operation unit 1, and the electric field and rotation drive body are controlled according to the output of each sensor. Will be done.

The gravity variable load generator of Patent Document 3 is used for a human muscle strength training device or the like. In this technique, when the load element is operated, each physical quantity of torque and angle is transmitted to the physical quantity detector. The output signal is amplified by an amplifier, and on the one hand, a viscous signal is introduced from the differentiating circuit and an inertial signal is introduced from the differentiating circuit. On the other hand, it is introduced from the amplifier as an elastic signal and a gravity signal. This combined signal energizes the driver circuit and energizes the friction element 2. Then, the gravity of the load element is continuously changed, and the load element allows a person to perform muscle strength training.

Further, the resonant motion device of Patent Document 4 shows a technique for generating vibration by using a motor in order to improve blood flow of a user.

Japanese Unexamined Patent Publication No. 2002-126122 Japanese Unexamined Patent Publication No. 2008-272361 Japanese Unexamined Patent Publication No. 5-180245 Japanese Unexamined Patent Publication No. 2017-148482

For example, as shown in Patent Document 4, there is a possibility of improving human blood flow by giving a human a vibration generated by an exercise device. In addition, such vibration is considered to be useful for preventing a decrease in bone density due to aging of human beings, for example.

However, the technique of Patent Document 4 requires a special actuator such as a motor to generate vibration. Further, such an actuator has a problem that it consumes a large amount of power and is fragile.

On the other hand, since the techniques of Patent Document 1 and Patent Document 2 use a ferrofluid, a special actuator such as a motor is not required. However, since the devices of Patent Document 1 and Patent Document 2 do not have a special configuration for generating regular vibration, they are used for improving human blood flow and preventing a decrease in bone density due to aging. Sufficient performance may not be obtained.

The vibration generator of the present invention is not limited to the health equipment or training equipment as in Patent Documents 1 to 4, and is expected to be used in various fields requiring vibration. For example, it is conceivable to use the vibration generator of the present invention as a vibration source of a vibration hopper installed in a factory or the like. That is, if the article conveyed by the belt conveyor is vibrated at a predetermined position on the belt conveyor, the article can be dropped to the side of the belt conveyor at that position.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vibration generator capable of generating desired vibration without requiring a special actuator such as a motor. It is in.

In order to achieve the above-mentioned object, the vibration generator according to the present invention is characterized by the following (1) to (4).
(1) Ring-shaped fixing member and
A disk-shaped movable member coaxially and rotatably supported inside the fixing member in the radial direction, with an inner peripheral edge portion of the fixing member and an outer peripheral edge portion of the movable member. A movable member arranged so as to face each other with a space in the axial direction of the fixed member and the movable member.
A functional fluid that is filled in the space and whose viscoelasticity changes in response to the application of a magnetic field.
It has a control unit that applies a magnetic field in a direction along the axial direction to the functional fluid filled in the space.
The control unit includes a vibration generating unit that generates the magnetic field based on a signal that changes with time and generates vibration in the sliding resistance between the movable member and the fixing member .
On the outer peripheral surface of the movable member, a plurality of plate-shaped portions protruding outward in the radial direction are provided so as to be arranged in the axial direction at intervals in the axial direction.
On the inner peripheral surface of the fixing member arranged so as to face the outer peripheral surface of the movable member in the radial direction, a plurality of recesses recessed outward in the radial direction correspond to the plurality of plate-shaped portions. It is provided so as to be arranged in the axial direction at intervals in the axial direction and to accommodate the plurality of plate-shaped portions.
For each of the plurality of plate-shaped portions, the outer surfaces of both ends of the plate-shaped portion in the axial direction and the inner surfaces of both ends of the concave portion accommodating the plate-shaped portion in the axial direction sandwich the space in the axial direction. Arranged to face each other,
Vibration generator.

According to the vibration generator having the configuration of (1) above, it is possible to generate desired vibration without requiring a special actuator such as a motor. For example, when MR fluid (Magneto Rheological Fluid) is used as a functional fluid, the control unit applies a magnetic field to the functional fluid, so that the ferromagnetic particles in the functional fluid attract each other. It forms a chain-like cluster structure and becomes semi-solid. Then, when the movable member and the fixed member move relatively, a shear stress is generated in the cluster structure, which becomes a resistance force against the relative movement of the movable member and the fixed member. Further, since the vibration generating unit in the control unit generates a magnetic field based on a signal that changes with time, the resistance force acting between the movable member and the fixed member also changes with time. Therefore, the change in resistance causes vibration in the sliding resistance between the movable member and the fixed member.

(2) The movable member is connected to the rotating shaft, and the movable member is connected to the rotating shaft.
The vibration generating portion generates vibration with respect to the rotational resistance of the rotating shaft.
The vibration generator according to (1) above.

According to the vibration generator having the configuration of (2) above, vibration is generated with respect to the rotational resistance of the rotating shaft. Therefore, for example, in a training device, the trainee can give a periodically fluctuating resistance to the rotation of the rotating shaft generated by the pedaling force, and the trainee can feel the vibration. Moreover, when the trainee finishes pedaling, the relative movement between the movable member and the fixed member disappears and the vibration stops, so no extra load is applied to the trainee and special control is possible. Not needed.

(3) The vibration generating portion changes the magnetic field based on a periodic rectangular wave.
The vibration generator according to (1) or (2) above.

According to the vibration generator having the configuration of (3) above, since the magnetic field is periodically changed by using a rectangular wave, the stress generated between the movable member and the fixed member can be changed rapidly. .. Therefore, larger vibrations will be generated, and favorable results can be obtained from the viewpoint of increasing the bone density of the human body, for example, in training equipment.

(4) The vibration generating unit superimposes a constant voltage on a signal that changes with time, thereby superimposing it on a constant sliding resistance to generate vibration.
The vibration generator according to any one of (1) to (3) above.

According to the vibration generator having the configuration of (4) above, the vibration can be adjusted by changing the signal with time, and the sliding resistance can be adjusted by superimposing a constant voltage, so that the vibration is generated when a constant sliding resistance is applied. Can be made to. Therefore, when the vibration generator is applied to a training device, not only the effect of increasing the bone density can be expected due to the vibration, but also the calorie consumption and the increase of the muscle mass can be expected due to the sliding resistance.

According to the vibration generator of the present invention, it is possible to generate desired vibration without requiring a special actuator such as a motor.

The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through the embodiments described below (hereinafter referred to as "embodiments") with reference to the accompanying drawings. ..

FIG. 1 is a perspective view showing an example of using an MR training device. FIG. 2 is a perspective view showing the appearance and cross-sectional structure of the braking mechanism included in the MR training device. FIG. 3 is a cross-sectional view showing a part of a cross section of the braking mechanism. FIG. 4 is a cross-sectional view showing a state in which a part of FIG. 3 is enlarged. 5 (a) and 5 (b) are cross-sectional views showing the state of the MR fluid in two states in which the magnetic field states are different from each other. FIG. 6 is a block diagram showing a configuration example of an electric circuit included in the MR training device. 7 (a) and 7 (b) are waveform diagrams showing an example of the voltage applied to the electromagnet coil. FIG. 8 is a graph showing the relationship between the current flowing through the electromagnet coil and the torque generated by the MR fluid. FIG. 9 is a time chart showing an example of the relationship between the voltage of the rectangular wave applied to the electromagnet coil and the torque generated by the MR fluid.

Specific embodiments of the present invention will be described below with reference to each figure.

<Appearance of equipment and usage examples>
FIG. 1 shows the appearance and usage example of the MR training device 10 including the vibration generator of the present invention. This MR training device 10 can be used by the trainee 13 for exercise to prevent a decrease in bone density due to aging or to improve blood flow. Further, in this exercise, the MR training device 10 can give the trainee 13 a machine vibration that repeats regularly.

The MR training device 10 shown in FIG. 1 includes an equipment frame 11, a support portion 12, a braking mechanism 14, and an operation portion 15 with a pedal. As shown in FIG. 1, the trainee 13 straddles the support portion 12 and performs a rowing operation on the pedal-equipped operation unit 15 with his / her feet resting on the pedal-equipped operation unit 15 as in the case of a bicycle. be able to.

The operation unit 15 with a pedal is connected to the rotation shaft of the braking mechanism 14. When the trainee 13 pedals the operation unit 15 with a pedal, the rotation axis of the braking mechanism 14 rotates. The braking mechanism 14 can apply braking to the rotation of the rotating shaft and apply a load to the movement of the trainee 13. Further, this load is accompanied by vibration generated by the braking mechanism 14. This vibration has the effect of preventing a decrease in bone density due to aging of the trainee 13, for example. Therefore, the braking mechanism 14 in FIG. 1 includes the vibration generator of the present invention.

<Details of braking mechanism 14>
FIG. 2 shows the appearance and cross-sectional structure of the braking mechanism 14 included in the MR training device 10. Further, FIG. 3 shows the configuration of the cross-sectional portion Pa of the braking mechanism 14 in FIG. Further, FIG. 4 shows a state in which a part of FIG. 3 is enlarged.

As shown in FIG. 2, the braking mechanism 14 includes a fixing member 21 having a ring-shaped outer shape and a disc-shaped disc rotor 22. The fixing member 21 is fixed to the equipment frame 11. The disc rotor 22 is supported by the fixing member 21 and is in a state of being rotatable inside the fixing member 21. Further, the central portion of the disc rotor 22 is connected to the cylindrical rotating shaft 23.

The cylindrical rotating shaft 23 is connected to the operation unit 15 with a pedal shown in FIG. Therefore, when the trainee 13 pedals the operation unit 15 with pedals, the cylindrical rotating shaft 23 rotates, and the disc rotor 22 also rotates.

As shown in FIGS. 2 and 3, an electromagnet coil 27 and an electromagnet yoke 28 are arranged inside the fixing member 21. The electromagnet coil 27 is formed in a ring shape at a position facing the outer circumference of the disc rotor 22. Further, the electromagnet yoke 28 is composed of an iron core which is a ferromagnet, and is formed in a shape that surrounds the outside of the electromagnet coil 27.

As shown in FIG. 3, the space 25a between the oil seal 24 arranged inside the fixing member 21 and the disc rotor 22 is filled with MR fluid (Magneto Rheological Fluid) 26. The MR fluid 26 exists in a state in which a large number of ferromagnetic particles such as iron powder are dispersed in a liquid such as oil. The particle size of the ferromagnetic particles is about several [μm].

As shown in FIG. 3, in a portion close to the outer periphery of the disc rotor 22, a plurality of plate-shaped portions formed in a thin plate shape are arranged so as to be arranged in the thickness direction at intervals from each other. Further, the thin plate-shaped portions on the fixing member 21 side are arranged so as to overlap between the plurality of plate-shaped portions of the disc rotor 22. That is, the thin plate-shaped portion on the disc rotor 22 side and the thin plate-shaped portion on the fixing member 21 side are laminated. However, there is a gap between them. Since the space 25b in these gaps communicates with the space 25a, the space 25b is also filled with the MR fluid 26.

The electromagnet yoke 28 is formed so as to sandwich the thin plate-shaped portion on the disc rotor 22 side and the thin plate-shaped portion on the fixing member 21 side from the outside. For example, in the state of the electromagnet coil 27 shown in FIG. 3, when a current is passed from above to below in the direction perpendicular to the paper surface, a magnetic field 29 as shown in FIG. 3 is generated around the electromagnet coil 27. The magnetic field 29 forms a magnetic path so as to pass through the electromagnet yoke 28 having a small magnetic resistance.

Therefore, the electromagnet coil 27 applies a relatively strong magnetic field to the MR fluid 26 in the space 25b where the thin plate-shaped portion on the disc rotor 22 side and the thin plate-shaped portion on the fixing member 21 side are laminated. Can be done. Further, when a magnetic field is generated by the electromagnet coil 27, as shown in FIG. 4, in the MR fluid 26 of each space 25b, a large number of ferromagnetic particles 26a attract each other to form a chain-like cluster. In such a state, a braking force is generated against the relative movement of the fixing member 21 and the disc rotor 22. Details will be described later.

<Principle of braking force generation>
The states of the MR fluid in two states in which the magnetic field states are different from each other are shown in FIGS. 5 (a) and 5 (b).

In a state where no magnetic field is applied from the outside, as shown in FIG. 5A, each ferromagnetic particle 26a in the MR fluid 26 exists in a dispersed state. Therefore, in the state of FIG. 5A, no braking force is generated for the rotational operation of the disc rotor 22.

On the other hand, when a magnetic field is applied from the outside, as shown in FIG. 5B, the ferromagnetic particles 26a in the MR fluid 26 attract each other to form a chain-like cluster structure and become semi-solid. That is, the disc rotor 22 and the fixing member 21 are connected via a chain-shaped cluster structure. Then, when the disc rotor 22 moves relative to the fixing member 21 with the rotation of the disc rotor 22, the chain-shaped cluster structure is sheared. Further, a stress is generated immediately before shearing, and this stress acts as a sliding resistance between the fixing member 21 and the disc rotor 22, that is, a braking force against rotation.

Further, in the situation where the application of the magnetic field is continued, the sheared chain-like cluster structure is immediately combined with the neighboring fragment (aggregation of the ferromagnetic particles 26a) to form a new chain-like cluster structure. .. This chain-shaped cluster structure is sheared again as the disk rotor 22 rotates, and stress is generated accordingly. By continuously repeating the above operations, the braking force continues to be generated. The change in kinetic energy due to this braking force is converted into the thermal energy of the MR fluid 26.

In the MR training device 10 shown in FIG. 1, the electromagnet coil 27 is intermittently and periodically driven by the control of an electric circuit described later. Therefore, as shown in FIG. 5B, a state in which a magnetic field is applied to generate a braking force and a state in which the magnetic field is released and a braking force is not generated occur alternately as shown in FIG. 5A. Therefore, a periodic fluctuation occurs in the torque of the braking force, which is transmitted as vibration from the operation unit 15 with a pedal to the trainee 13.

If the trainee 13 stops rowing the operation unit 15 with a pedal, the rotation of the disc rotor 22 is stopped, so that the change in torque applied to the operation unit 15 with a pedal, that is, vibration is eliminated. Therefore, when the trainee 13 wants to take a break, it is possible to automatically stop the extra load as vibration from being applied to the trainee 13 simply by stopping the operation of the operation unit 15 with a pedal. Further, even when the training is started, the vibration does not occur until the trainee 13 starts the operation of the operation unit 15 with the pedal, and the vibration starts at the same time when the operation unit 15 with the pedal is rowed. An MR training device 10 that is easy to handle for 13 can be realized. Moreover, there is no need to install a special sensor and no complicated control is required.

<Example of electrical circuit configuration>
FIG. 6 shows a configuration example of the electric circuit included in the MR training device 10 shown in FIG.
The electric circuit shown in FIG. 6 includes a rectangular wave generator 51, a driver circuit 52, a vibration frequency adjusting unit 53, and an offset adjusting unit 54.

The square wave generator 51 can output a continuous square wave signal. The vibration frequency adjusting unit 53 generates an instruction for changing the frequency (reciprocal of the reciprocal cycle) of the rectangular wave output by the rectangular wave generator 51 according to the instruction of the user or the like. When the MR training device 10 is used in a general state, the frequency of the square wave output by the square wave generator 51 is set to, for example, about 50 [Hz], and the fundamental frequency of the generated vibration is set to 100 [Hz]. It is expected to be adjusted.

It is conceivable to use a waveform other than the square wave as the signal output by the square wave generator 51, but when a sine wave waveform is used, for example, the change in torque is gentler than that of the square wave. Therefore, it is expected that the intensity of the generated vibration will decrease.

The driver circuit 52 amplifies the signal output by the square wave generator 51, and applies the voltage VL of the square wave to the electromagnet coil 27. The current I flows through the electromagnet coil 27 by applying the voltage VL. The offset adjusting unit 54 adjusts the offset of the voltage VL output by the driver circuit 52. The driver circuit 52 adds a DC bias voltage corresponding to the offset amount output by the offset adjusting unit 54 to the voltage VL and outputs the DC bias voltage to the electromagnet coil 27.

Instead of adjusting the offset, the amplitude of the rectangular wave of the voltage VL may be adjusted, or both adjustments may be used in combination. Further, when the vibration frequency and the vibration intensity are adjusted in advance to the optimized state, the vibration frequency adjusting unit 53 and the offset adjusting unit 54 do not necessarily have to be provided.

<Example of voltage VL waveform>
Examples of the waveform of the voltage VL applied to the electromagnet coil 27 are shown in FIGS. 7 (a) and 7 (b). FIG. 7A shows an example of a voltage VL waveform when there is no offset, and FIG. 7B shows an example of a voltage VL waveform when a positive DC bias voltage is added and offset. Represents.

When the waveform of the voltage VL shown in FIG. 7 (a) is applied to the electromagnet coil 27, a braking force of torque corresponding to the amplitude of the voltage VL is applied to the operation unit 15 with a pedal as a load, and the polarity of the square wave is changed. Vibration is transmitted to the operation unit 15 with a pedal due to the torque change generated every half cycle of switching. Further, when the waveform of the voltage VL is offset as shown in FIG. 7B, the amplitude of the half cycle is increased as compared with the case where there is no offset, and the braking torque during this period is increased. The difference in the polarity of the voltage VL does not affect the torque or the vibration intensity.

<Specific examples of torque characteristics>
FIG. 8 shows a specific example of the relationship between the current I flowing through the electromagnet coil 27 and the braking torque T [Nm] generated by the MR fluid 26. Further, FIG. 9 shows a specific example of the relationship between the voltage VL of the square wave applied to the electromagnet coil 27 and the braking torque T generated by the MR fluid 26.

As is clear from the characteristics shown in FIG. 8, the braking torque T changes so as to be substantially proportional to the magnitude of the current I flowing through the electromagnet coil 27. Therefore, as the voltage VL of the rectangular wave applied to the electromagnet coil 27 increases, the braking torque T also increases.

Further, as shown in FIG. 9, when the voltage VL of the rectangular wave is applied to the electromagnet coil 27, the braking torque T changes abruptly at each timing when the polarity of the voltage VL is switched. Therefore, vibration is generated as a change in the braking torque T every half cycle of the rectangular wave of the voltage VL. Further, as the amplitude of the rectangular wave of the voltage VL increases, the magnitude of the vibration also increases. It is also possible to use a waveform such as a sine wave instead of a rectangular wave, but in that case, it is considered that the vibration intensity is lowered.

<Advantages of MR training device 10>
Since the MR training device 10 shown in FIG. 1 employs a braking mechanism 14 that utilizes the MR fluid 26, it does not require a solid actuator such as an electric motor. Therefore, it is possible to easily realize a device that consumes less power and is not easily broken. Further, since the MR training device 10 generates vibration, it is considered to be useful for preventing a decrease in bone density due to aging of human beings and improving blood flow, for example.

Further, in the MR training device 10, vibration is generated by a change in braking force (resistance), so that even if the electromagnet coil 27 is in a constant control state, the trainee 13 performs an operation of rowing the operation unit 15 with a pedal. Vibration occurs only when it happens. Therefore, it is possible to provide the MR training device 10 which is kind to the trainer 13 and has good operability. That is, it is safe because it is possible to automatically prevent an unnecessary load from being applied to the trainer 13 before the start of the training or after the end of the training. Moreover, since it is not necessary to install a special sensor or switch and it is not necessary to perform complicated control, the cost of the MR training device 10 can be reduced.

<Possibility of deformation>
In the MR training device 10 described above, the braking mechanism 14 employs the MR fluid 26 as the functional fluid, but instead of the MR fluid 26, another functional fluid such as an ER fluid (Electro-Rheological Fluids) is used. It is also possible to use it. However, when the ER fluid is adopted, the stress generated tends to be smaller than that of the MR fluid, so that it is desirable to adopt the MR fluid in the application of the MR training device 10.

In the above-described embodiment, it is assumed that the vibration generator of the present invention is applied to the MR training device 10, but this vibration generator can be used for various purposes. For example, it is conceivable to use the vibration generator of the present invention for a vibration hopper used in a manufacturing process of a factory. That is, when an article such as a part is conveyed by the belt conveyor, by giving vibration to the article at a predetermined position, the article can be dropped from the belt conveyor to sort or switch the conveying route. In that case, since the belt conveyor moves at a constant speed, a braking force is applied to this movement by the same principle as the braking mechanism 14, and the electromagnet coil 27 is intermittently driven by an AC signal. , Can generate continuous vibration.

Further, the voltage VL applied to the electromagnet coil 27 is not limited to a periodic waveform, but is not limited to a periodic waveform, is one that changes sporadically, one that changes randomly with time, one that fluctuates the period, and one that includes fluctuations in the period. Anything that causes vibration due to a change in braking torque T, such as, is sufficient, and the optimum waveform is selected according to the application of the vibration generator.

Here, the features of the vibration generator according to the embodiment of the present invention described above are briefly summarized and listed below in [1] to [4], respectively.
[1] Fixing member (21) and
A movable member (disc rotor 22) arranged at a position facing the fixing member, and
A functional fluid (MR fluid 26) that is filled in the space between the movable member and the fixed member and whose viscoelasticity changes in response to the application of an electric field or a magnetic field.
It has a control unit (driver circuit 52, electromagnet coil 27) that applies an electric field or a magnetic field to the functional fluid.
The control unit generates the electric field or magnetic field based on a signal that changes with time, and generates vibration in the sliding resistance between the movable member and the fixed member (square wave generator). 51)
Vibration generator (braking mechanism 14).

[2] The movable member is connected to a rotating shaft (cylindrical rotating shaft 23), and the movable member is connected to the rotating shaft (cylindrical rotating shaft 23).
The vibration generating portion generates vibration with respect to the rotational resistance of the rotating shaft.
The vibration generator according to the above [1].

[3] The vibration generating portion changes the electric field or the magnetic field based on a periodic rectangular wave (see FIG. 9).
The vibration generator according to the above [1] or [2].

[4] The vibration generating unit superimposes a constant voltage on a signal that changes with time, thereby superimposing it on a constant sliding resistance to generate vibration.
The vibration generator according to any one of the above [1] to [3].

10 MR training device 11 Equipment frame 12 Support part 13 Trainer 14 Braking mechanism 15 Operation part with pedal 21 Fixing member 22 Disc rotor 23 Cylindrical rotating shaft 24 Oil seal 25a, 25b Space 26 MR fluid 26a Electromagnetic coil 27 Electromagnetic coil 28 Electromagnet yoke 29 Magnetic field 51 Rectangular wave generator 52 Driver circuit 53 Vibration frequency adjustment part 54 Offset adjustment part Pa Cross section VL voltage

Claims (4)

With a ring-shaped fixing member,
A disk-shaped movable member coaxially and rotatably supported inside the fixing member in the radial direction, with an inner peripheral edge portion of the fixing member and an outer peripheral edge portion of the movable member. A movable member arranged so as to face each other with a space in the axial direction of the fixed member and the movable member.
A functional fluid that is filled in the space and whose viscoelasticity changes in response to the application of a magnetic field.
It has a control unit that applies a magnetic field in a direction along the axial direction to the functional fluid filled in the space.
The control unit includes a vibration generating unit that generates the magnetic field based on a signal that changes with time and generates vibration in the sliding resistance between the movable member and the fixing member .
On the outer peripheral surface of the movable member, a plurality of plate-shaped portions protruding outward in the radial direction are provided so as to be arranged in the axial direction at intervals in the axial direction.
On the inner peripheral surface of the fixing member arranged so as to face the outer peripheral surface of the movable member in the radial direction, a plurality of recesses recessed outward in the radial direction correspond to the plurality of plate-shaped portions. It is provided so as to be arranged in the axial direction at intervals in the axial direction and to accommodate the plurality of plate-shaped portions.
For each of the plurality of plate-shaped portions, the outer surfaces of both ends of the plate-shaped portion in the axial direction and the inner surfaces of both ends of the concave portion accommodating the plate-shaped portion in the axial direction sandwich the space in the axial direction. Arranged to face each other,
Vibration generator. The movable member is connected to the rotating shaft, and the movable member is connected to the rotating shaft.
The vibration generating portion generates vibration with respect to the rotational resistance of the rotating shaft.
The vibration generator according to claim 1. The vibration generating portion changes the magnetic field based on a periodic rectangular wave.
The vibration generator according to claim 1 or 2. The vibration generating unit superimposes a constant voltage on a signal that changes with time, thereby superimposing it on a constant sliding resistance to generate vibration.
The vibration generator according to any one of claims 1 to 3.

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