JPH10132672A - Torque sensor, and power-steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque sensor that can set the zero point of a detection torque precisely and can detect the level of the torque from the zero point accurately. SOLUTION: A pair of cam surfaces 88 and 89 are formed at one of a traveling body 80 that is engaged to a first shaft 71 so that it can travel in axial direction and a positioning body 84 that is mounted to a second shaft 72 being connected to the first shaft 71 elastically and concentrically so that it can be rotated relatively and a support part 90 that pressed elastically against the cam surfaces 88 and 89 is provided at the other. Both cam surfaces 88 and 89 are simultaneously brought into contact with the support part 90 to prevent the traveling body 80 from moving in one direction of axial directions when the relative rotary positions of both shafts 71 and 72 are located at reference positions. When both shafts 71 and 72 rotate relatively, the cam surfaces 88 and 89 move the traveling body 80 in the other direction of the axial directions. The both cam surfaces 88 and 89 are symmetrical each other relative to a plane that includes the axis center of the both shafts 71 and 72. A torque signal corresponding to the traveling distance in axial direction of the traveling body 80 is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a torque sensor,
The present invention relates to a power steering device controlled based on a steering torque detected by the torque sensor.

[0002]

2. Description of the Related Art A torque sensor disclosed in Japanese Patent Laid-Open Publication No. Sho 62-3632 includes a first shaft, a second shaft elastically connected to the first shaft so as to be relatively rotatable around a coaxial center, and a second shaft. A moving body is fitted to the first shaft so as to be movable in the axial direction, and a positioning body attached to the second shaft. A cam surface is formed on the moving body, a receiving portion that can contact the cam surface is provided on the positioning body, and a spring that presses the receiving portion against the cam surface is provided. The cam surface can move the moving body in one axial direction by displacing the contact point with the receiving portion at the time of relative rotation of both shafts in one direction, and also, relative rotation of both shafts in the other direction. At times, by displacing the contact point with the receiving portion, the moving body can be moved in the other axial direction. A differential transformer for outputting an electric signal corresponding to the moving distance of the moving body in the axial direction as a torque signal is provided.

[0003] The torque sensor is used in a power steering device to detect not only the magnitude of the steering torque but also the direction. Therefore, when the first shaft and the second shaft are relatively rotated in one direction and in the other direction, the moving direction of the moving body in the axial direction is set to the opposite direction,
The steering torque at the time of right steering and the steering torque at the time of left steering are identifiable.

That is, FIG. 6A shows a receiving portion 102 which comes into contact with a cam surface 101 in a straight-ahead steering state, and the cam surface 101 is inclined with respect to the axial direction of both shafts (the direction of arrow P in the figure). Surface. When the vehicle is steered to one side, the contact point between the cam surface 101 and the receiving portion 102 is displaced upward in the drawing, and the moving body moves in one direction in the axial direction.
When the contact is made on the other side, the contact point is displaced downward in the figure, and the moving body is displaced in the other axial direction. Thereby, as shown in (2) of FIG. 6, the sign of the output of the differential transformer when steered to the right and the sign of the output of the differential transformer when steered to the left are opposite to each other. I have to.

[0005]

The above conventional torque sensor can directly identify the sign of the detected torque, but cannot set the zero point of the detected torque accurately. This is because the receiving portion 102 cannot be accurately positioned at a fixed position on the cam surface 101 in the conventional configuration. Therefore, it is not necessary to directly identify the sign of the detected torque, and when it is necessary to detect the magnitude of the torque from the zero point, sufficient detection accuracy cannot be obtained.

For example, in a power steering apparatus including a pump driven by a motor and a hydraulic actuator that generates a steering assisting force by pressure oil from the pump, the rotation speed of the motor is controlled to save energy. The steering assist speed is set only during assisting, and the standby speed is set when steering assist is released.
In such a power steering device, since the steering assist force can be applied by hydraulic pressure, there is no direct need to detect the sign of the steering torque. On the other hand, in order to change the rotation speed of the motor, it is conceivable to determine the necessity of the steering assist based on the magnitude of the steering torque. However, the conventional torque sensor cannot accurately determine the magnitude of the steering torque, and cannot perform appropriate steering assistance.

An object of the present invention is to provide a torque sensor and a power steering device that can solve the above-mentioned problems.

[0008]

A torque sensor according to the present invention comprises a first shaft, a second shaft elastically connected to the first shaft so as to be relatively rotatable around a coaxial center, and a shaft connected to the first shaft. A moving body fitted so as to be movable in the direction and a positioning body attached to the second shaft are provided. A pair of cam surfaces is formed on one of the moving body and the positioning body, and a receiving portion that can contact each cam surface is provided on the other of the moving body and the positioning body. Means are provided for exerting an elastic force pressing the cam surface. The two cam surfaces can be simultaneously in contact with the receiving portion so that the moving body can be prevented from moving in one of the axial directions when the relative rotation position of the two shafts is at a fixed reference position. One cam surface is shaped so that the moving body can be moved in the other axial direction by displacing the contact point with the receiving portion during relative rotation of the two shafts in one direction. The other cam surface is shaped so that the moving body can be moved in the other axial direction by displacing the contact point with the receiving portion during relative rotation of the two shafts in the other direction. If the relative rotation amounts are the same between the reference positions of both shafts in one direction from the reference position and in the other direction, the two cam surfaces are moved so that the moving distance of the moving body in the axial direction becomes equal. Are symmetrical with respect to a plane including the axis of both shafts. Means for outputting a torque signal corresponding to the axial movement distance of the moving body is provided.

According to the configuration of the torque sensor of the present invention, when the first shaft and the second shaft elastically rotate in one direction in response to the transmission torque, one cam surface displaces the contact point with the receiving portion. To move the moving body in the other axial direction.
When the first shaft and the second shaft elastically rotate in the other direction in response to the transmission torque, the other cam surface displaces the contact point with the receiving portion, and moves the moving body in the other axial direction. Since the moving distance of the moving body in the axial direction corresponds to the torque transmitted by both shafts, it can be output as a torque signal corresponding to the moving distance in the axial direction. The two cam surfaces can simultaneously contact the receiving portion so as to prevent the moving body from moving in one of the axial directions when the relative rotation position of the two shafts is at a fixed reference position. As a result, the receiving portion can be accurately positioned at a fixed position with respect to the two cam surfaces. At that position, the moving body is prevented from moving in the axial direction, so that the zero point of the detected torque can be set accurately. Both cam surfaces are symmetrical to each other with respect to a plane including the axis of both shafts, so that the relative rotation between the reference position of both shafts in one direction and that in the other direction is relative. If the amounts are equal, the moving distances of the moving bodies in the axial direction are equal. Thus, the magnitude of the torque can be accurately detected regardless of the sign of the torque.

It is preferable to provide a means for guiding the moving body in the axial direction of both shafts. As a result, even when the relative rotation position of both shafts is not at a fixed reference position, the receiving portion can be accurately positioned at a position corresponding to the relative rotation amount of both shafts with respect to each cam surface, and the magnitude of torque can be accurately determined. Can be detected.

[0011] The power steering apparatus according to the present invention comprises:
A hydraulic actuator that generates a steering assist force by pressure oil from a pump driven by an electric motor, and a unit that sets a rotation speed of the motor to a steering assist speed during steering assist and a standby speed when steering assist is released; Means for determining whether or not to perform steering assistance based on the magnitude of the steering torque. The magnitude of the steering torque is detected by the torque sensor of the present invention.

According to the power steering apparatus of the present invention, the magnitude of the steering torque is accurately detected by the torque sensor of the present invention, and it is determined whether or not to perform the steering assist based on the magnitude of the steering torque. Thus, it is possible to accurately determine the necessity of the steering assist, perform the appropriate steering assist, and save energy. In addition, in the straight steering state, the two cam surfaces are simultaneously in contact with the receiving portion to prevent the moving body from moving in one of the axial directions, thereby improving the sense of stability when the steering wheel is straight and improving the steering feeling. .

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

The rack and pinion type power steering device 1 shown in FIG. 1 includes an input shaft 2 connected to a steering wheel H, and an output shaft 4 connected to the input shaft 2 via a torsion bar 3. The torsion bar 3 is connected to the input shaft 2 via a pin 5 and to the output shaft 4 via a serration 6. Its output shaft 4
A rack 8 meshing with the pinion 7 is connected to steering wheels (not shown). The input shaft 2 is connected to a valve housing 10 via a bearing 9.
a and is supported by the output shaft 4 via a bush 11. The output shaft 4 is supported by the rack housing 10b via bearings 12 and 13. As a result, the rotation of the input shaft 2 due to the steering is transmitted to the pinion 7 via the torsion bar 3, and the rack 8 moves in the vehicle width direction, and the wheels are steered by the movement of the rack 8. Note that oil seals 14, 15 are provided between the input / output shafts 2, 4 and the valve housing 10a. Also,
A support yoke 16 for supporting the rack 8 is provided. The support yoke 16 is pressed against the rack 8 by the elastic force of a spring 17.

A hydraulic cylinder 18 is provided as a hydraulic actuator for applying a steering assist force. The hydraulic cylinder 18 includes a cylinder tube configured by the rack housing 10b, a piston 20 formed integrally with the rack 8, and a pair of oil chambers 21 and 22 partitioned by the piston 20. A rotary hydraulic control valve 23 is connected to each of the oil chambers 21 and 22. The control valve 23 includes a cylindrical first valve member 24 and a second valve member 2 that is rotatably inserted into the first valve member 24.
5 is provided. The first valve member 24 is connected to the output shaft 4
Is mounted so as to be rotatable together with a pin 26 via a pin 26.
The second valve member 25 is formed integrally with the outer periphery of the input shaft 2.

As shown in FIG. 2, a plurality of recesses along the axial direction are formed on the inner periphery of the first valve member 24 and the outer periphery of the second valve member 25 at equal intervals in the circumferential direction. The first valve member-side recess is composed of four right steering recesses 27 located at equal intervals in the circumferential direction and four left steering recesses 28 located at equal intervals in the circumferential direction. The second valve member-side recess is composed of four pressure oil supply recesses 29 located at equal intervals in the circumferential direction and four pressure oil discharge recesses 30 located at equal intervals in the circumferential direction. Each right steering recess 27 and each left steering recess 28 are alternately arranged in the circumferential direction, and each pressure oil supply recess 29 and each pressure oil discharge recess 30 are alternately arranged in the circumferential direction. Each right steering recess 27 is
As shown in FIG. 1, one of the oil chambers 2 of the hydraulic cylinder 18 passes through a first flow path 31 formed in the first valve member 24 and a first port 32 formed in the valve housing 10a.
Lead to 1. Each left steering recess 28 is provided with the first valve member 2.
2 and the second flow path 33 formed in the valve housing 1
Through the second port 34 formed at 0a, the oil port 22 communicates with the other oil chamber 22 of the hydraulic cylinder 18. Each pressure oil supply recess 29
Is a third flow path 35 formed in the first valve member 24 and an inlet port 36 formed in the valve housing 10a.
Through the pump 37 as shown in FIG. The pump 37 is driven by a motor 50, and can be configured by, for example, a vane pump or a gear pump that discharges pressure oil at a flow rate according to the rotation speed of the motor 50. Each pressure oil discharge recess 30 is formed in the first discharge passage 38 formed in the second valve member 25, the passage 47 between the input shaft 2 and the inner and outer circumferences of the torsion bar 3, and the input shaft 2 shown in FIG. 1. Second discharge path 3
9 and a tank 41 via a discharge port 40 formed in the valve housing 10a. Thus, the pump 37, the tank 41, and the oil chambers 21 and 22 of the hydraulic cylinder 18 communicate with each other through the inter-valve flow path 42 between the inner and outer circumferences of the first valve member 24 and the second valve member 25. Between the first valve member side concave portion and the second valve member side concave portion in the inter-valve flow path 42, there are formed throttle portions A, B, C, D whose opening degree changes due to relative rotation of the two valve members 24, 25. ,
The hydraulic pressure acting on the hydraulic cylinder 18 is controlled by the change in the opening degree of the throttle portions A, B, C, D.

FIG. 2 shows the relative positions of the two valve members 24 and 25 at the midpoint of the steering angle where steering is not being performed. In this state, since each pressure oil supply recess 29 and each pressure oil discharge recess 30 communicate with each other through all the throttle portions A, B, C, and D,
The pressure oil supplied from the pump 37 is directly returned to the tank 41 and does not generate a steering assist force. Therefore, it is not necessary to drive the motor 50 at a steering assist speed required for steering assist.

When the steering is steered rightward from the steering angle midpoint, the torsion bar 3 is twisted in accordance with the steering torque, and the two valve members 2 are twisted.
4 and 25 rotate relatively. As a result, each right steering recess 2
The opening degree of the throttle A between each of the pressure oil supply recesses 29 and the throttle B between each of the left steering recesses 28 and each of the pressure oil discharge recesses 30 increases. The opening degree of the throttle portion C between the steering recess 28 and each pressure oil supply recess 29 and the opening degree of the throttle portion D between each right steering recess 27 and each pressure oil discharge recess 30 are reduced. . As a result, pressure oil is supplied from the pump 37 to one oil chamber 21 of the hydraulic cylinder 18, and the pressure oil is returned from the other oil chamber 22 of the hydraulic cylinder 18 to the tank 41, and the steering assist force to the right of the vehicle is provided. Acts on the rack 8.

When the steering is steered to the left from the steering angle midpoint, the degree of opening of each of the throttle portions A, B, C, and D changes oppositely to the case where the steering is steered to the right. Acts on the rack 8.

As shown in FIG. 1, the motor 50 is connected to a controller 60. The controller 60
It has a control circuit 61 and a drive circuit 62. The control circuit 61 is mainly composed of a computer, is connected to a torque sensor 70 for detecting the magnitude of the steering torque, and outputs an instruction signal corresponding to the detected torque to the drive circuit 62. The drive circuit 62 is connected to a battery power supply 63 and supplies a drive current corresponding to an instruction signal from the control circuit 61 to the motor 5.
Send to 0.

As shown in FIG. 3 (1), (2) and FIG. 4, the torque sensor 70 comprises a first shaft 71 and a second shaft 71.
And a shaft 72. One of the shafts 71 and 72 is connected to the steering wheel H, and the other is connected to the input shaft 2.

The recess 7 formed in the first shaft 71
One end of a torsion bar 73 is joined to the inner periphery of 1a via a serration 74, and the other end of the torsion bar 73 is inserted into a concave portion 72a formed in the second shaft 72 and is connected to the second shaft 72 by a pin 75. Joined. As a result, the second shaft 72 becomes the first shaft 71
Are elastically connected to a coaxial center so as to be relatively rotatable.

A housing 76 is provided to cover the connection between the shafts 71 and 72. The housings 76 support the shafts 71 and 72 via bearings 77 and 78.

The first shaft 71 is provided with a cylindrical moving body 8.
0 is fitted via a plurality of balls 81 so as to be movable in the axial direction. As shown in FIG.
And a plurality of grooves 71b, 80b
Are formed along the axial direction, and the ball 81 can roll in each groove, so that the moving body 80 is smoothly guided in the axial direction. One end of the moving body 80 is disposed in the recess 72 a of the second shaft 72.

A positioning body 84 is attached to the second shaft 72. In the present embodiment, the positioning body 84
Is constituted by a ball bearing, and the second shaft 72
In the recess 72a. The support shaft 85 press-fitted into the inner ring is fixed by being screwed to the second shaft 72. The axis of the support shaft 85 is orthogonal to the axis of the second shaft 72. A lock nut 86 is screwed onto the support shaft 85.

The movable body 80 has a pair of cam surfaces 88, 89.
Is formed by an inner surface of a notch formed on one end side (the left side in FIG. 3 (2)) of the moving body 80.
The two cam surfaces 88 and 89 are formed so that the distance between the two cam surfaces 88 and 89 increases gradually toward one end of the moving body 80.
Both shafts 71, 7 are inclined with respect to the axial direction of
The shapes are symmetric with respect to a plane including the axis of the second shaft and the shaft of the support shaft 85.

The outer periphery of the outer ring of the bearing constituting the positioning body 84 is formed as a receiving portion 90 which can contact each of the cam surfaces 88 and 89.

A compression coil spring 92 is sandwiched between the other end surface of the moving body 80 and a retaining ring 91 for fixing the bearing 77 attached to the first shaft 71.
Due to the resilience of the spring 92, the receiving portion 90 is moved to each cam surface 8
8, 89.

The state shown in (2) of FIG. 3 is a straight steering state,
That is, the steering torque is not acting on both shafts 71, 72, and in this state both shafts 71, 7
The second relative rotational position is set as a reference position. When the relative rotational positions of the shafts 71 and 72 are at the reference position, the cam surfaces 88 and 89 are provided on the receiving portion 90 so as to prevent the moving body 80 from moving in one axial direction (leftward in FIG. 3). Contact at the same time.

The torsion bar 73 is twisted by the reaction force acting from the road surface during steering to the left or right, and
When the first and the second 72 are relatively rotated in one direction, the other cam surface 89 is rotated.
The cam surface 88 and the receiving portion 9
The displacement of the contact point with 0 causes the moving body 80 to move in the other axial direction (to the right in FIG. 3). Also, the torsion bar 7 is driven by the reaction force acting from the road surface when steering to the other side.
When the shaft 3 is twisted and the shafts 71 and 72 rotate relative to each other in the other direction, one cam surface 88 and the receiving portion 90 are separated from each other, and the contact point between the other cam surface 89 and the receiving portion 90 is displaced. The body 80 moves in the other axial direction (to the right in FIG. 3). As described above, the cam surfaces 88 and 89 are symmetrical to each other with respect to the plane including the axis of the shafts 71 and 72 and the axis of the support shaft 85.
When the relative rotation amounts of the first and second reference positions 72 and 73 in the one direction and the other direction are equal, the moving distance of the moving body 80 in the axial direction is equal.

A coil 96 constituting a differential transformer 95 with the moving body 80 is attached to the inner periphery of the housing 76. The differential transformer 95 is
The electric signal corresponding to the axial movement distance of the control circuit 6
Output to 1. The electric signal becomes a torque signal corresponding to the magnitude of the steering torque. That is, both shafts 71,
When the base member 72 elastically rotates relative to one direction in response to the steering torque, the positioning body 84 displaces the contact point between the cam surface 88 and the receiving part 90, and moves the moving body 80 to the other axial direction,
When both shafts 71 and 72 elastically rotate in the other direction elastically in accordance with the steering torque, the other cam surface 89 and the receiving portion 90
Is displaced, and the moving body 80 is moved in the other axial direction. Since the moving distance in the axial direction of the moving body 80 corresponds to the steering torque, an electric signal corresponding to the moving distance in the axial direction can be output as a torque signal. FIG. 5 shows the relationship between the output of the torque signal and the steering torque.

The control circuit 61 determines whether or not to perform steering assistance based on the magnitude of the steering torque corresponding to the torque signal. For example, when the magnitude of the detected steering torque exceeds a set torque value that can be regarded as a straight-ahead steering state, it is determined that steering is performed. When the magnitude of the steering torque does not exceed the set torque value, or when the magnitude of the steering torque does not exceed the set torque value for the set time after it is determined that the steering is performed, it is determined that no steering is performed. When the control circuit 61 determines that steering is performed, an instruction signal for setting the rotation speed of the motor 50 to the steering assist speed is output to the drive circuit 62. A current is supplied so as to achieve the auxiliary speed. The steering assist speed is a speed preset so that the flow rate of the pressure oil sent from the pump 37 becomes a flow rate necessary for steering assist. In addition, a vehicle speed sensor connected to the control circuit 61 is separately provided, and the steering assist speed of the motor 50 is changed according to the vehicle speed. At low vehicle speeds, the steering assist force is increased to improve the turning performance of the vehicle. In this case, the steering assist force may be reduced to improve the running stability of the vehicle. If the control circuit 61 determines that there is no steering, no instruction signal is output to the drive circuit 62 to set the rotation speed of the motor 50 to the steering assist speed. If the rotation speed of the motor 50 is already the steering assist speed, an instruction signal for setting the rotation speed of the motor 50 to the standby speed is output to the drive circuit 62, and in response to the instruction signal, the drive circuit 62 The current is supplied so that the rotation speed becomes the standby speed, or if the standby speed is zero, the power supply to the motor 50 is stopped.

According to the above construction, both cam surfaces 88, 89
When both shafts 71 and 72 are at the reference position, that is, at the time of straight-ahead steering, they come into contact with the receiving portion 90 simultaneously so as to prevent the moving body 80 from moving in one axial direction. As a result, the receiving portion 90 can be accurately positioned at a fixed position with respect to the two cam surfaces 88 and 89. At that position, the receiving portion is prevented from moving in the axial direction, so that the zero point of the steering torque can be set accurately. Can be. In addition, since both cam surfaces 88 and 89 are symmetrical with respect to a plane including the axis of both shafts 71 and 72 and the axis of support shaft 85, one direction from the reference position of both shafts 71 and 72. When the relative rotation amounts are the same between the relative rotation in the direction of rotation and the direction of the relative rotation in the other direction, the moving distance of the moving body 80 in the axial direction becomes equal.
Thus, the magnitude of the steering torque can be accurately detected regardless of the sign of the steering torque, that is, regardless of the steering direction. Further, since the moving body 80 can be smoothly guided in the axial direction via the ball 81, even when the shafts 71 and 72 are not at the reference positions, the receiving portion 90 can be moved to the respective cam surfaces 88 and 89.
In contrast, the positioning can be accurately performed at a position corresponding to the relative rotation amount of both shafts 71 and 72, and the magnitude of the steering torque can be accurately detected. Accordingly, it is possible to accurately determine the necessity of the steering assist based on the magnitude of the detected steering torque, perform the appropriate steering assist, and save energy. In the straight steering state, both cam surfaces 88, 89
By simultaneously contacting the receiving portion 90 and preventing the moving body 80 from moving in the axial direction, the sense of stability when the steering wheel moves straight can be improved, and the steering feeling can be improved.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the positioning body 84 is formed of a ball bearing, but a pin having an outer periphery coated with a low wear material such as Teflon may be used. Further, a receiving portion may be provided on the moving body, and a cam surface may be formed on the positioning body. Further, the shape of each cam surface is not limited to the above embodiment. Further, the output of the torque signal is not limited to the differential transformer, but may be any as long as it can output a torque signal corresponding to the axial movement distance of the moving body.

[0035]

According to the present invention, it is possible to provide a torque sensor capable of accurately setting the zero point of the detected torque and accurately detecting the magnitude of the torque from the zero point. It is possible to provide a power steering device capable of performing steering assist and saving energy.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a power steering device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a partial cross-sectional view of the torque sensor according to the embodiment of the present invention, and FIG.

FIG. 4 is a sectional view taken along the line IV-IV of FIG.

FIG. 5 is a diagram showing a relationship between a steering torque and an output of the torque sensor according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating a problem in a conventional torque sensor, and FIG. 6B is a diagram illustrating a relationship between a steering torque and an output.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power steering device 37 Pump 50 Motor 60 Controller 71 First shaft 72 Second shaft 80 Moving body 84 Positioning body 88, 89 Cam surface 90 Receiving part 92 Spring 95 Differential transformer

Claims (3)

[Claims] A first shaft; a second shaft elastically coaxially connected to the first shaft so as to be relatively rotatable; a moving body fitted to the first shaft so as to be movable in an axial direction; A positioning body attached to the second shaft, a pair of cam surfaces are formed on one of the moving body and the positioning body, and the other of the moving body and the positioning body is in contact with each cam surface. A possible receiving portion is provided, and means for exerting an elastic force for pressing the receiving portion against each cam surface is provided. When the relative rotation position of both shafts is at a fixed reference position, the moving member shaft is provided. It is possible to simultaneously contact the receiving portion so as to prevent movement in one direction, and one cam surface displaces a contact point with the receiving portion during relative rotation of both shafts in one direction, so that the moving body The other in the axial direction The other cam surface has a shape that can move the moving body in the other axial direction by displacing the contact point with the receiving portion during relative rotation of both shafts in the other direction. When the relative rotation amount is equal between the relative rotation in one direction from the reference position of both shafts and the relative rotation in the other direction,
Both cam surfaces are symmetrical with respect to a plane including the axis of both shafts so that the moving distance in the axial direction of the moving body is equal, and a torque signal corresponding to the axial moving distance of the moving body is output. A torque sensor provided with a means. 2. The torque sensor according to claim 1, further comprising means for guiding the moving body in the axial direction of both shafts. 3. A hydraulic actuator for generating a steering assist force by pressure oil from a pump driven by an electric motor, and a rotational speed of the motor is set to a steering assist speed at the time of steering assist, and a standby speed is set at a time of canceling the steering assist. And a means for determining whether or not to perform steering assistance based on the magnitude of the steering torque, wherein the magnitude of the steering torque is detected by the torque sensor according to claim 1 or 2. Power steering device.