JPH11190672A - Torque sensor and power steering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque sensor compact, high in output sensitivity and economical. SOLUTION: Input and output shafts 2, 4 are elastically connected to each other in response to transmission torque so as to be relatively rotatable around the same axis. A second receiving part 72 corotatable with the output shaft 4 can be movable in the axial direction of the input and output shafts 2, 4 relatively to a first receiving part 71 corotatable with the input shaft 2, according to the relative rotating quantity of the input and output shafts 2, 4. A receiving position of a detecting part 83 pressed to both receiving parts 71, 72 by resilience can be changed according to the relative moving quantity of both receiving parts 71. 72 so that the detecting part 83 is moved in the radial direction of the input and output shafts 2, 4 according to the relative moving quantity of both receiving parts 71, 72. A signal corresponding to transmission torque can be outputted on the basis of the change of resilience for pressing the detecting part 83 to both receiving parts 71, 72.

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 using the torque sensor.

[0002]

2. Description of the Related Art In a power steering apparatus provided with a hydraulic actuator for generating a steering assist force by pressure oil from a pump driven by a motor, when the motor is constantly maintained at a speed necessary for steering assist, a power supply for the motor is provided. Battery energy is wasted.

[0003] Therefore, it has been attempted to reduce the fuel consumption of the vehicle by setting the rotation speed of the motor to the steering assist speed only during the steering assist, and to the standby speed when the steering assist is released.

[0004] Whether the rotational speed of the motor is set to a steering assist speed or a standby speed is determined based on a steering torque detected by a torque sensor.

Conventionally, as the torque sensor, there has been provided means for converting the relative rotation amount of the input / output shaft according to the steering torque into a change in the magnetic resistance in the magnetic circuit, and a sensor for detecting the steering torque based on the change in the magnetic resistance. A contact type is used. This non-contact type torque sensor can detect the value of the steering torque over a wide range.

[0006]

The above-mentioned non-contact type torque sensor has a problem that the size is increased due to the necessity of forming a magnetic circuit.

Further, as described above, when judging whether the rotational speed of the motor should be set to the steering assist speed or the standby speed from the steering torque, it is sufficient to be able to judge the presence or absence of steering.
It is not necessary to detect the value of the steering torque over a wide range. That is, the conventional torque sensor has more performance than necessary for the above-described power steering device and is uneconomical.

In the power steering apparatus as described above, control for controlling the pressure oil supplied to the hydraulic actuator in accordance with the relative rotation amount of the input / output shaft which is elastically and relatively rotatably connected in accordance with the steering torque. A valve may be used. In this case, when the steering torque is zero, it is necessary to set the relative rotational position of the input shaft and the output shaft to a position where the hydraulic oil does not act on the hydraulic actuator. On the other hand, when the steering torque is detected using a conventional non-contact torque sensor, when the steering torque is zero, the relative rotation position between the input shaft and the output shaft is reduced to zero when the change in the magnetic resistance in the magnetic circuit is zero. It must be set to a certain position. However, when the steering torque is zero, the relative rotational position of the input / output shaft for the control valve,
It is difficult to match the relative rotational position of the input / output shaft for the torque sensor. Therefore, the control characteristics of the hydraulic pressure and the detection accuracy of the torque are adversely affected.

[0009] It is an object of the present invention to provide a torque sensor and a power steering device that can solve the above problems.

[0010]

According to the present invention, there is provided a torque sensor comprising: an input shaft; an output shaft elastically connected to the input shaft so as to be relatively rotatable around a coaxial center in response to a transmission torque; A first receiving portion rotatable with the output shaft, and a first receiving portion rotatable with the output shaft thereof; and
A second receiving portion movable relative to the first receiving portion in the axial direction of the input / output shaft in accordance with a relative rotation amount of the input / output shaft; and a detecting portion movable in a radial direction of the input / output shaft. And means for imparting elasticity to press the detection unit against both receiving units. The receiving position of the detecting unit by the two receiving units can be changed according to the relative movement amount of the both receiving units so that the detecting unit moves in the radial direction of the input / output shaft according to the relative moving amount of the both receiving units. You. The elasticity of pressing the detection unit against the two receiving units can be changed according to the amount of movement of the detection unit. A signal corresponding to the torque transmitted by the input / output shaft can be output based on a change in the elasticity of pressing the detection unit against both receiving units. According to the configuration of the present invention, when the input shaft and the output shaft rotate relative to each other according to the transmission torque, the two receiving portions move relative to each other in the axial direction of the input / output shaft according to the relative rotation amount. The receiving position of the detecting unit by the two receiving units changes according to the relative movement amount of the two receiving units. Due to this change in the receiving position, the detecting unit moves in the radial direction of the input / output shaft in accordance with the relative movement amount of the two receiving units. The elasticity of pressing the detection unit against the two receiving units changes according to the amount of movement of the detection unit. Since the change in elasticity corresponds to the transmitted torque, a signal corresponding to the value of the torque transmitted by the input / output shaft can be output based on the change in elasticity. Thereby, the transmission torque can be detected without forming a magnetic circuit, and the configuration can be made compact.

The two receiving portions of the torque sensor according to the present invention are disposed so as to face each other with an axial interval between the input and output shafts.
A cam mechanism provided between the two receiving portions; and a means for providing elasticity for pressing the two receiving portions against each other via the cam mechanism. The cam mechanism causes the two receiving portions to rotate relative to the input / output shaft. The input and output shafts can move relative to each other in the axial direction according to the amount, and the outer peripheral sides of the opposing surfaces of the two receiving portions are receiving surfaces that approach each other toward the inner periphery. Preferably, the detection unit is received by Thereby, the second receiving portion can be relatively moved in the axial direction of the input / output shaft with respect to the first receiving portion in a compact configuration in accordance with the relative rotation amount of the input / output shaft. It can be moved in the radial direction of the input / output shaft. The sensor output corresponds to the continuous change in the elasticity, and the detection range of the transmission torque can be arbitrarily set according to the shape of the cam surface in the cam mechanism. It is economical because the torque of the motor can be detected without excess or shortage.

[0012] It is preferable that the relative rotational position of both receiving portions can be changed without changing the relative rotational position of the input / output shaft. Thereby, the relative rotation position of both receiving portions is changed without relative rotation of the input / output shaft, the second receiving portion is relatively moved in the axial direction of the input / output shaft, and the detection portion is moved in the radial direction of the input / output shaft. Thus, the output of the torque sensor can be changed. Therefore, the output of the torque sensor when the transmission torque is zero can be adjusted to a value corresponding to the state where the transmission torque is zero, without being affected by the relative rotational position of the input / output shaft.

A power steering apparatus according to the present invention includes a torque sensor according to the present invention, a hydraulic actuator for generating a steering assist force by pressure oil from a pump driven by a motor, and a hydraulic oil supplied to the hydraulic actuator. A control valve for controlling a hydraulic pressure in accordance with a relative rotation amount of the input / output shaft in accordance with a steering torque, and control means for setting a rotation speed of the motor to a steering assist speed during steering assist and a standby speed to cancel steering assist. The control means determines whether the rotational speed of the motor is a steering assist speed or a standby speed based on the output of the torque sensor. According to this configuration, it is possible to determine whether to set the rotation speed of the motor to the steering assist speed or the standby speed based on the output of the torque sensor of the present invention. Since the power steering device can be shared, the power steering device can be made compact, the necessity of steering can be accurately determined, and the cost can be reduced by preventing an increase in the number of parts and a complicated configuration. When the steering torque is zero, the output of the torque sensor can be adjusted to a value corresponding to the state where the steering torque is zero, without being affected by the relative rotational position of the input / output shaft. Therefore, when the steering torque is zero, the relative rotational position of the input / output shaft is set to a position at which the hydraulic oil does not act on the hydraulic actuator, and the output of the torque sensor is a value corresponding to the state where the steering torque is zero. Can be adjusted. Thereby, it is possible to prevent the detection accuracy of the torque sensor and the control accuracy of the control valve from being influenced by each other.

[0014]

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

A rack and pinion type power steering device 1 shown in FIG. 1 has an input shaft 2 connected to a steering wheel H, and a torsion bar that allows the input shaft 2 to elastically rotate relative to a coaxial center elastically in accordance with a steering torque. And an output shaft 4 connected to the output shaft 3.
The torsion bar 3 is connected to the input shaft 2 via a pin 5 and the output shaft 4 via a serration 6.
It is connected to. A pinion 7 is formed on the output shaft 4, and a rack 8 meshing with the pinion 7 is connected to wheels (not shown). The input shaft 2 is supported by a valve housing 10 a via a bearing 9, and is supported by an output shaft 4 via a bush 11. Its output shaft 4 is the bearing 1
It is supported by the rack housing 10b via 2 and 13. Thereby, when the rotation of the input shaft 2 due to steering is transmitted to the pinion 7 via the torsion bar 3, the rack 8 moves in the vehicle width direction, and the steering angle changes. Oil seals 14, 15 are provided between the input / output shafts 2, 4 and the valve housing 10a. Further, a support yoke 16 for supporting the rack 8 is provided.
Is pressed against.

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 integrated 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. Its control valve 23
Has a first valve member 24 having a cylindrical shape, and a second valve member 25 inserted into the first valve member 24 so as to be relatively rotatable. The first valve member 24 is rotatably attached to the output shaft 4 via a pin (not shown). The second valve member 25 is connected to the input shaft 2.
Are formed integrally on the outer periphery of the.

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 corresponding 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. It communicates with the tank 41 via a second discharge path 39 and 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 via the 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 recess and the second valve member side recess in the inter-valve flow path 42, both valve members 2
Aperture portion A whose opening changes due to relative rotation of 4, 25,
B, C, and D, and 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, and D.

FIG. 2 shows the relative positions of the two valve members 24 and 25 at the steering angle midpoint where steering is not 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 supplied to the tank 41.
Reflux to Therefore, no steering assist force is generated, and 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 elastically twisted in accordance with the steering torque, and the two valve members 24 and 25 rotate elastically relative to the input / output shafts 2 and 4. As a result, the opening degree of the throttle portion A between each right steering recess 27 and each pressure oil supply recess 29 and the throttle portion B between each left steering recess 28 and each pressure oil discharge recess 30.
The opening of the throttle portion C between each left steering recess 28 and each pressure oil supply recess 29 and the opening between each right steering recess 27 and each pressure oil discharge recess 30 are increased. The degree of opening of the throttle portion D is 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 wheel is steered to the left from the middle of the steering angle, the degree of opening of each of the throttle portions A, B, C, and D changes in reverse to the case where the steering device 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 has a control circuit 61 and a drive circuit 62.

The control circuit 61 is mainly composed of a computer, is connected to the torque sensor 51 and the vehicle speed sensor 53, and outputs an instruction signal to the drive circuit 62 according to a stored control program.

The drive circuit 62 is connected to the motor 50 and the battery power supply 63, and drives the motor 50 in response to an instruction signal from the control circuit 61.
As the power control switching element, a known element including a transistor such as an FET can be used.

The torque sensor 51 is disposed between the control valve 23 and the oil seal 15 in the valve housing 10a, and includes input / output shafts 2 and 4 for transmitting the steering torque as constituent elements.

As shown in FIG. 3, an annular first receiving portion 71 is connected to the outer periphery of the input shaft 2 so as to be rotatable with the input shaft 2. In the present embodiment, since the inner periphery of the first receiving portion 71 is pressed into the outer periphery of the input shaft 2, the first receiving portion 71 cannot be displaced in the axial direction with respect to the input shaft 2.

As shown in FIGS. 3 and 4, one end of the output shaft 4 has forked portions 4a and 4b.
4a and 4b are inserted into a pair of openings 71a and 71b formed in the first receiving portion 71 as shown by a two-dot chain line in FIG. Inner circumference of each opening 71a, 71b and forked part 4
A gap is formed between the outer circumferences of a and b to allow relative rotation according to the steering torque of the input shaft 2 and the output shaft 4.

A second receiving portion 72 is connected to the output shaft 4 so as to be rotatable with the output shaft 4 and to be movable in the axial direction. As a result, the first receiving portion 71 and the second receiving portion 72 face each other with a gap in the axial direction of the input / output shaft,
The second receiving portion 72 is movable relative to the first receiving portion 71 in the axial direction of the input shaft 2. In the present embodiment, the second receiving portion 72 has an annular main body 72a and a cylindrical portion 72b extending in the axial direction from the inner periphery of the main body 72a. The outer diameter of the main body 72a is equal to the outer diameter of the first receiving portion 71. V-shaped grooves 72c are formed along the axial direction at a plurality of positions on the inner periphery of the cylindrical portion 72b at circumferential intervals.

An annular base ring 73 is provided on the output shaft 4, and a base ring 7 is provided on the outer periphery of the output shaft 4.
3 is fixed by press fitting. One end of the outer periphery of the base ring 73 is a tapered surface 73a having a smaller diameter toward the one end.

The cylindrical retainer 7 is attached to the base ring 73.
4 is provided with a male screw 73a formed on the outer circumference of the base ring 73 and a female screw 74a formed on the inner circumference of the retainer 74.
Are fixed by screwing, and a lock nut 75 is screwed into a male screw 73a on the outer periphery of the base ring 73.

A second receiving portion 72 is provided on the outer periphery of the retainer 74.
The inner circumference of the cylindrical portion 72b is fitted so as to be movable in the axial direction. Holding holes 74 formed at a plurality of positions (four positions in this embodiment) at equal intervals in the circumferential direction of the retainer 74.
The ball 76 is inserted in each of b. Each ball 76 is supported by the tapered surface 73a of the base ring 73 and the inner surface of the groove 72c of the second receiving portion 72, so that it can roll in the axial direction of the input / output shafts 2, 4. In addition, the circumferential movement is prevented. This allows
The second receiving portion 72 is rotatable with the output shaft 4 and is movable in the axial direction.

A cam mechanism 80 is provided between the first receiving portion 71 and the second receiving portion 72. The cam mechanism 80
The cam surfaces 71e and 72e formed at a plurality of positions (four positions in the present embodiment) at equal circumferential intervals on the surfaces of the two receiving portions 71 and 72 facing each other, and the two receiving portions 71 and 72 A plurality (four in the present embodiment) of ball-shaped cam followers 81 are arranged therebetween. Each cam surface 71e,
72e is formed by recessing the opposing surfaces of both receiving portions 71, 72 in a conical shape. Each cam follower 81 includes a cam surface 71 e of the first receiving portion 71 and the second receiving portion 7.
And the second cam surface 72e.

The compression coil spring 82 fitted on the outer periphery of the cylindrical portion 72b of the second receiving portion 72 is sandwiched between the main body 72a of the second receiving portion 72 and the lock nut 75. The two receiving portions 71 and 72 are pressed against each other via the cam mechanism 80 by the elasticity given by the spring 82.

When the steering torque transmitted by the input / output shafts 2, 4 is zero, the first receiving portion 71 and the second receiving portion 7
2 are arranged so as to be closest to each other. That is, when the steering torque is zero, as shown in FIG. 5A, each of the cam followers 81 has its own cam surface 71e, 72e.
Is the most deeply penetrated state. As a result, when the receiving portions 71 and 72 rotate relative to each other by the same amount as the relative rotation amount of the input / output shafts 2 and 4 due to the change in the steering torque, each cam follower 81 and each cam follower as shown in FIG. The contact points between the surfaces 71e and 72e change, and the second receiving portion 72 moves relative to the first receiving portion 71 in the axial direction of the input / output shafts 2 and 4 according to the relative rotation amount.
The interval between 1, 72 becomes large. That is, both receiving portions 7
The reference numerals 1 and 72 relatively move in the axial direction of the input / output shafts 2 and 4 according to the relative rotation amount of the input / output shafts 2 and 4.

The outer peripheral sides of the opposing surfaces of the two receiving portions 71 and 72 are connected to the receiving surfaces 7 which approach each other toward the inner periphery.
1 'and 72'. A ball-shaped detector 83 that can move in the radial direction of the input / output shafts 2 and 4 is received by the two receiving surfaces 71 ′ and 72 ′. The compression coil spring 85 is sandwiched between the detection portion 83 and the load detection sensor 84 fitted in the through hole 10a 'formed in the valve housing 10a. Due to the elasticity provided by the spring 85, the detecting portion 83 is provided with two receiving surfaces 71 ',
72 '.

Since the two receiving surfaces 71 ', 72' come closer to each other toward the inner circumference, the two receiving portions 71, 7 are moved by the relative movement of the input / output shafts 2, 4 of the second receiving portion 72 in the axial direction.
2, the receiving position of the detection unit 83 is changed. By changing the receiving position, the detecting unit 8 is moved in accordance with the relative movement amount of the second receiving unit 72 along the axial direction of the input / output shafts 2 and 4.
Reference numeral 3 moves in the radial direction of the input / output shafts 2, 4. For example, in FIG. 3, when the two receiving portions 71 and 72 are separated from each other due to an increase in the steering torque, the detecting portion 83 located at the solid line approaches the input / output shafts 2 and 4 as indicated by a two-dot chain line. In addition, both receiving portions 71 and 7 are reduced due to a decrease in steering torque.
When the two approach each other, the detection unit 83 separates from the input / output shafts 2 and 4. The movement amount of the detection unit 83 corresponds to the steering torque.

In accordance with the amount of movement of the detecting portion 83, the detecting portion 83 provided by the spring 85 is moved to both receiving portions 71, 7
The elasticity pressing on 2 changes. The change in the elasticity corresponds to the steering torque corresponding to the amount of movement of the detection unit 83. The elasticity provided by the spring 85 is detected by the load detection sensor 84. The load detection sensor 84 outputs a signal corresponding to the steering torque transmitted by the input / output shafts 2 and 4 to the control circuit 61 based on a change in the elasticity of pressing the detection portion 83 against the receiving portions 71 and 72. .

The control circuit 61 determines whether to set the rotation speed of the motor 50 to the steering assist speed or the standby speed based on the output of the torque sensor 51 corresponding to the steering torque. That is, the detected value of the steering torque detected by the torque sensor 51 is compared with a preset and stored set value, and it is determined whether or not the detected value is equal to or larger than the set value. The set value is determined based on the value of the steering torque that requires steering assistance. If the detected value is equal to or larger than the set value, the control circuit 61 outputs an instruction signal to the drive circuit 62 to set the rotation speed of the motor 50 to the steering assist 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. The steering assist speed is determined by the vehicle speed sensor 5
3 according to the vehicle speed detected. That is, the steering assist speed is determined so that the steering assist force is increased at a low vehicle speed to improve the turning performance of the vehicle, and at a high vehicle speed, the steering assist force is reduced to improve the running stability of the vehicle.

If the detected steering torque is less than the set value, the control circuit 61 outputs to the drive circuit 62 an instruction signal for setting the rotation speed of the motor 50 to the standby speed. The standby speed is a preset speed smaller than the steering assist speed, and is set to zero in the present embodiment, but may be a value larger than zero. In response to the instruction signal, the drive circuit 62 cuts off the current to the motor 50, whereby the rotation speed of the motor 50 becomes the standby speed and the steering assist is released.

According to the above configuration, when the input and output shafts 2 and 4 rotate relative to each other in accordance with the transmitted steering torque, the second receiving portion 72 moves in the axial direction of the input and output shafts 2 and 4 in accordance with the relative rotation amount. Move relative to. According to the relative movement amount of the second receiving portion 72, the receiving position of the detecting portion 83 by the two receiving portions 71 and 72 changes. Due to the change in the receiving position, the detecting unit 83 moves in the radial direction of the input / output shafts 2 and 4 according to the relative movement amount of the second receiving unit 72. In accordance with the amount of movement of the detection unit 83, the elasticity of the spring 85 that presses the detection unit 83 against both the receiving units 71 and 72 changes. Since the change in the elasticity corresponds to the steering torque, the load detection sensor 84 can output a signal corresponding to the steering torque based on the change in the elasticity. Thereby, the steering torque can be detected without using a magnetic circuit, and the configuration can be made compact.

Further, the cam mechanism 80 is connected to both receiving portions 71, 72.
Between the input and output shafts 2 and 4 in a compact configuration because the detection unit 83 is received by the receiving surfaces 71 'and 72' on the outer peripheral side of the opposing surfaces of the receiving units 71 and 72. Accordingly, the second receiving portion 72 can be relatively moved in the axial direction of the input / output shafts 2 and 4, and the detecting portion 83
Can be moved in the radial direction of the input / output shafts 2 and 4. The sensor output corresponds to a continuous change in elasticity,
Since the detection range of the transmission torque can be set arbitrarily according to the shape of the cam surfaces 71e and 72e in the cam mechanism 80, the output sensitivity can be easily increased, and the torque in the required range can be detected without excess or deficiency. It is something. Further, the output of the load detection sensor 84 is configured to become the maximum output when the steering torque is zero, and to decrease as the steering torque increases from zero. Can be prevented from being affected by noise or the like.

Based on the output of the torque sensor 51, it can be determined whether the rotation speed of the motor 50 is set to the steering assist speed or the standby speed, and the torque sensor 51 and the power steering device 1 are used as input components. Since the output shafts 2, 4 and the torsion bar 3 can be used in common, the power steering device 1 can be made compact, the necessity of steering assist can be accurately determined, and the number of parts is increased, the structure is prevented from becoming complicated, and the cost is reduced. Can be achieved.

Further, according to the above configuration, the base ring 7
By changing the amount of screwing of the retainer 74 with respect to the third receiving portion 71, the relative rotation position of the second receiving portion 72 with respect to the first receiving portion 71 can be changed without changing the relative rotating position of the input / output shafts 2, 4. . Thereby, the relative rotation position of both receiving portions 71 and 72 is changed without relatively rotating input / output shafts 2 and 4, and second receiving portion 72 is relatively moved in the axial direction of input / output shafts 2 and 4, and The output of the torque sensor 51 can be changed by moving the detection unit 83 in the radial direction of the output shafts 2 and 4. That is, the torque sensor 51 when the steering torque is zero is not affected by the relative rotational position of the input / output shafts 2 and 4.
Can be adjusted to a value corresponding to a state where the steering torque is zero. Therefore, in a state where the steering torque is zero, the relative rotation position of the input / output shafts 2 and 4 is set to a position where the hydraulic oil does not act on the hydraulic cylinder 18 and the output of the torque sensor 51 is set to a state where the steering torque is zero. Therefore, it is possible to prevent the detection accuracy of the torque sensor 51 and the control accuracy of the control valve 23 from being influenced by each other.
When the steering torque is zero, the input / output shafts 2, 4
Is set to a position where the hydraulic oil does not act on the hydraulic cylinder 18 by relatively rotating the input / output shafts 2 and 4 to adjust the opening degrees of the throttle portions A, B, C and D. Thereafter, the pin 5 can be used to connect the torsion bar 3 and the input shaft 2.

Further, the first receiving portion 71 is fitted to the input shaft 2, and the second receiving portion 72 is connected to the ball 76 and the retainer 7.
4. The torque sensor is fitted to the output shaft 4 via the base ring 73 and held via the lock nut 75 and the spring 82, and the cam mechanism 80 and the detecting section 83 are interposed between the receiving sections 71 and 72. 51 can be assembled and is excellent in assemblability.

The present invention is not limited to the above embodiment. For example, the first receiving portion may be relatively movable in the axial direction with respect to the input shaft. In short, both receiving portions are relatively movable in the axial direction of the input / output shaft according to the relative rotation amount of the input / output shaft. I just need. Further, the cam mechanism may be one in which a cam follower provided on one of the input / output shafts and a cam surface provided on the other of the input / output shafts are in direct contact with each other. Further, a method of determining whether the rotation speed of the motor is set to the steering assist speed or the standby speed based on the output of the torque sensor is not particularly limited. For example, if the change speed of the detected torque is equal to or more than the set value, the steering assist The speed may be set to a standby speed if the value is equal to or less than a set value for a certain period of time. Further, the use of the torque sensor is not particularly limited. For example, the torque sensor may be used to detect a steering torque to determine the degree of urgency of the steering from the change speed of the steering torque, or to detect a torque other than the steering torque.

[0045]

According to the present invention, an economical torque sensor which is compact, has a high output sensitivity and is economical, and a power steering which can accurately determine the necessity of steering to save energy and reduce costs. Equipment can be provided.

[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 sectional view of a main part of the power steering device according to the embodiment of the present invention;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

5A and 5B are diagrams showing a state where the torque is zero, and FIG. 5B is a diagram showing a state where the torque changes from zero in the cam mechanism of the torque sensor according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 power steering device 2 input shaft 3 torsion bar 4 output shaft 18 hydraulic cylinder (hydraulic actuator) 23 control valve 37 pump 50 motor 51 torque sensor 60 controller 71 first receiving portion 72 second receiving portion 71 ', 72' receiving surface 80 Cam mechanism 82 Spring 83 Detector 84 Load detection sensor 85 Spring

Claims (4)

[Claims] An input shaft, an output shaft elastically connected to the input shaft so as to be relatively rotatable coaxially in response to a transmission torque, a first receiving portion rotatable with the input shaft, A second receiving portion rotatable with the output shaft and relatively movable in the axial direction of the input / output shaft in accordance with a relative rotation amount of the input / output shaft with respect to the first receiving portion; A detection unit movable in the radial direction of the shaft, and a means for applying elasticity to press the detection unit against both receiving units, and the detecting unit is provided with a radial direction of the input / output shaft in accordance with a relative movement amount of the both receiving units. The receiving position of the detecting unit by the two receiving units can be changed according to the relative movement amount of the two receiving units, and the elasticity of pressing the detecting unit against the two receiving units depends on the moving amount of the detecting unit. Can change according to Is, based on a change in elasticity for pressing the sensing portion at both receiving portions, the torque sensor can output a signal corresponding to the torque transmitted by the input and output shafts. And a cam mechanism provided between the two receiving portions, and an elastic force for pressing the two receiving portions through the cam mechanism. The cam mechanism allows the both receiving portions to move relative to each other in the axial direction of the input / output shaft in accordance with the relative rotation amount of the input / output shaft. The torque sensor according to claim 1, wherein the outer peripheral side of the opposing surfaces is a receiving surface that approaches each other as it goes toward the inner periphery, and the detecting unit is received by both receiving surfaces. 3. The torque sensor according to claim 1, wherein the relative rotational position of the two receiving portions can be changed without changing the relative rotational position of the input / output shaft. 4. A torque sensor according to claim 1, a hydraulic actuator for generating a steering assist force by hydraulic oil from a pump driven by a motor, and a hydraulic actuator supplied to the hydraulic actuator. A control valve that controls the oil pressure of the hydraulic oil in accordance with the relative rotation amount of the input / output shaft in accordance with the steering torque; and sets the rotation speed of the motor to the steering assist speed when assisting steering and to the standby speed when canceling steering assist. A power steering device comprising: a control unit that determines whether the rotation speed of the motor is a steering assist speed or a standby speed based on an output of the torque sensor. Steering device.