JP3532964B2 - Valve device and hydraulic power steering device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve device for changing the opening of a throttle portion by rotating a spool and a valve device for controlling a steering assist force according to operating conditions such as vehicle speed and steering angle. TECHNICAL FIELD The present invention relates to a hydraulic power steering device.

[0002]

2. Description of the Related Art A conventional power steering system is provided with an input / output shaft that rotates relative to a steering resistance and a rotary control valve that controls a hydraulic pressure for generating a steering assist force according to the relative rotation amount of the input / output shaft. More used. In such a power steering device, a regulating device that regulates the relative rotation of the input / output shaft according to the hydraulic pressure, a valve device that regulates the hydraulic pressure that acts on the regulating device by squeezing the pressurized oil by rotating the spool, and By providing a control device for driving the spool to rotate by a stepping motor in accordance with operating conditions, it is possible to satisfy the high responsiveness of steering during low speed traveling and the stability of steering during high speed traveling.

As shown in FIG. 15, the valve device 10 is provided.
No. 0 forms an insertion hole 111 by inserting the sleeve 101 into the housing 110, and the spool 102 is inserted into the insertion hole 111 so as to be rotatable relative to the housing 110 side about its own axis. A through-hole penetrating the peripheral wall of the sleeve 101 forms a housing-side pressure oil passage 103 that communicates with the pump, and the pressure oil passage 103 has an opening 103a in the inner periphery of the insertion hole 111. A through-hole that radially penetrates the spool 102 forms a spool-side pressure oil passage 104 that communicates with a regulating unit that regulates the relative rotation of the input / output shaft according to the hydraulic pressure.
04 has an opening 104a on the outer circumference of the spool 102. The overlapping portion of the openings 103a and 104a serves as a pressure oil throttle portion between the housing side and the spool side. The spool 102 is connected to the stepping motor 105 via a speed reduction mechanism 108, so that the spool 102 is rotationally driven relative to the sleeve 101. The opening 103a of the pressure oil passage 103 on the housing side can be closed by a closing surface constituted by the outer peripheral surface of the spool 102, and the closing area of the opening 103a by the closing surface allows relative rotation of the spool 102 with respect to the housing side. The aperture area of the diaphragm portion is variable by changing based on this. Further, a drain passage 112 that connects the pressure oil passage 104 on the spool side to a tank (not shown) is formed along the axial center of the spool 102, and the drain passage 11
2 has a narrowing function by having a small diameter.

In FIG. 8A, the relative positional relationship between the opening 103a of the housing side pressure oil passage 103 and the opening 104a of the spool side pressure oil passage 104 is shown by a rotation step of the stepping motor 105 (one step is a sleeve of the spool 102). It corresponds to the unit relative rotation angle with respect to 101, and the rotation step increases as the vehicle speed increases). In the figure, the sleeve 1 is in the left-right direction.
01 and the circumferential direction of the spool 102, the up-down direction is the axial direction of the spool 102, both openings 103a, 104a
The center positions of the two coincide with each other in the axial direction of the spool 102. It should be noted that the overlapping portion of both openings 103a and 104a, which will be the narrowed portion, is shown by hatching. The stepping motor 105 rotates in a direction to increase the opening area of the diaphragm portion as the speed increases, and rotates in a direction to decrease the opening area of the diaphragm portion as the speed decreases. As a result, during high-speed traveling, the opening area of the throttle portion becomes large and the hydraulic pressure that regulates the relative rotation of the input / output shaft becomes large. As shown in FIG. 7, the ratio of the hydraulic pressure for generating the steering assist force to the steering input torque increases. Is reduced and steering stability is improved. Further, when the vehicle is traveling at a low speed, the opening area of the throttle portion becomes small and the hydraulic pressure that regulates the relative rotation of the input / output shaft becomes small. As shown in FIG. Therefore, high responsiveness of steering can be achieved. In addition, during medium-speed traveling, high responsiveness of steering is achieved compared to during high-speed traveling, and steering stability is achieved compared to during low-speed traveling.

[0005]

In the above conventional valve device 100, since the rotation angle of the spool 102 per step of the stepping motor 105 is large,
The change in the aperture area of the diaphragm portion per step also becomes large. Then, there is a problem in that the steering assist force suddenly changes due to a change in vehicle speed, and the steering feeling deteriorates.

Therefore, it is conceivable to increase the reduction ratio of the reduction mechanism 108 for reducing the rotation of the stepping motor 105 to reduce the amount of change in the aperture area of the diaphragm portion with respect to the rotation of the stepping motor 105 per step. However, if the reduction ratio of the reduction mechanism 108 is increased, there is a problem that the device becomes large.

Further, in the above structure, since the pressure oil passage 104 on the spool side is formed by the through hole penetrating the spool 102, the passage area of the pressure oil rapidly expands when passing through the throttle portion. Therefore, there is a problem that bubbles are generated in the pressure oil and a flow noise is generated. Therefore, it is conceivable to reduce the diameter of the through hole forming the pressure oil passage 104 on the spool side to reduce the passage area. However, if the diameter of the through hole is reduced, the spool 102
The housing side pressure oil passage 1
The opening 103a of No. 03 and the opening 104a of the spool side pressure oil passage 104 are completely overlapped with each other, and the adjustable range of the opening of the throttle portion is narrowed.

A drain passage 112 having a throttle function is also provided.
When the valve is formed along the shaft center of the spool 102, the inner diameter of the drain passage 112 must be accurately finished in order to accurately control the hydraulic pressure that regulates the relative rotation of the input / output shaft. However, it is difficult to accurately finish the inner diameter of the small-diameter hole, and there is a problem that the processing cost increases.

The above problem is not limited to the valve device used in the hydraulic power steering device, but is also a problem in the valve device that adjusts the opening degree of the throttle portion of the pressure oil by the relative rotation of the sleeve with respect to the housing.

It is an object of the present invention to provide a valve device which can solve the above-mentioned problems of the prior art.

[0011]

The valve device of the present invention comprises:
The housing includes a housing and a spool that is inserted into an insertion hole formed on the housing side. The spool is rotatable relative to the housing side about its own axis, and pressure oil is applied to the housing side and the spool side, respectively. A passage is formed, and the pressure oil passage on the housing side has an opening in the inner circumference of the insertion hole, and the opening can be closed by a closing surface formed by a part of the outer circumferential surface of the spool. Part of the surface is a flat surface that is recessed from the outer peripheral surface.
The plane has a pair of edges along the axial direction of the spool and one end of each of the pair of edges as its both ends.
Of possess the edges along the radial direction of the spool, between the inner peripheral surface of the planar insertion hole constitutes a hydraulic fluid passage in the spool side, its
The flat surface of the spool is recessed from the outer peripheral surface of the spool to form a step connected to the edge along the radial direction.
On the edge along the direction and the outer circumference of the spool at the step
A region surrounded by an outer edge along the opening and a peripheral edge of the opening serves as a throttle portion of the pressure oil between the housing-side pressure oil passage and the spool-side pressure oil passage, and a closing surface of the opening by a closing surface thereof with respect to the housing side of the spool. The aperture area of the diaphragm portion is variable by changing based on the relative rotation.

A part of the outer peripheral surface of the spool is a second plane parallel to the plane, and the second plane has a greater distance from the axis of the spool than the plane, and the second plane and the plane. It is preferable that the drain passage is defined by the outer edge of the step, and the second flat surface and the inner peripheral surface of the insertion hole communicate with the pressure oil passage on the spool side and have a drain function.

The hydraulic power steering system of the present invention is
An input / output shaft that rotates relative to the steering resistance, a rotary control valve that controls the hydraulic pressure for generating steering assist force according to the amount of relative rotation of the input / output shaft, and the relative rotation of the input / output shaft is controlled according to the hydraulic pressure. In the hydraulic power steering apparatus including the regulating means, the hydraulic pressure acting on the regulating means can be adjusted by squeezing the pressure oil by the valve device of the present invention, and the spool can be adjusted with respect to the housing side according to operating conditions. A control device is provided that is driven to rotate by a stepping motor.

[0014]

According to the structure of the valve device of the present invention, the closing surface that closes the opening of the housing-side pressure oil passage in the inner periphery of the insertion hole and the plane that forms the spool-side pressure oil passage with the inner peripheral surface of the insertion hole. Is formed by a part of the outer peripheral surface of the spool. A region surrounded by an edge along the axial direction of the plane, an outer edge of a step connected to the edge along the radial direction of the plane, and a peripheral edge of the opening is a throttle portion of the pressure oil. Due to the relative rotation of the spool with respect to the housing side, the opening area of the throttle portion of the pressure oil changes. Therefore, the opening area change amount of the throttle portion per unit relative rotation amount with respect to the housing of the spool can be set according to the axial relative position of the step and the opening along the radial direction. As a result, when a means for rotating the spool relative to the housing by a constant rotation angle is provided, the unit relative rotation of the spool with respect to the housing can be performed without reducing the area of the opening or the radial dimension of the plane. It is possible to sufficiently reduce the amount of change in the opening area of the throttle unit per unit amount.

Further, since the spool-side pressure oil passage is formed between the outer peripheral flat surface of the spool and the inner peripheral surface of the insertion hole, the spool-side pressure oil passage is formed by the through hole of the spool as in the conventional case. Compared with the case, if the radial dimension of the plane and the diameter of the through hole are the same, the passage area of the pressure oil passage on the spool side can be reduced. As a result, by reducing the passage area of the pressure oil passage on the spool side, it is possible to prevent the passage area of the pressure oil that has passed through the throttle portion from rapidly expanding, and to prevent bubbles from being generated in the pressure oil. The flow noise can be prevented and the flow noise can be reduced, and moreover, the radial dimension of the plane can be sufficiently increased to prevent the adjustable range of the opening of the throttle portion from being narrowed.

It is preferable that a plurality of the throttle portions are provided at equal intervals in the circumferential direction of the spool. As a result, the hydraulic pressure acting on the spool in a radial direction is balanced, and it is possible to prevent the closing surface of the spool and the inner peripheral surface of the insertion hole from being twisted.

A drain passage communicating with the pressure oil passage on the spool side and having a throttle function is provided between the second flat surface on the outer periphery of the spool and the inner peripheral surface of the insertion hole. Compared with the construction, it is easy to finish the dimensions of the drain passage with high accuracy, and the processing cost can be reduced.

According to the hydraulic power steering system of the present invention, even if the steering conditions such as the vehicle speed and the steering angle change, the hydraulic pressure acting on the regulating means does not change rapidly, but the steering assist force changes rapidly. Therefore, it is possible to prevent the steering feeling from deteriorating.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rack and pinion type hydraulic power steering system 1 according to a first embodiment shown in FIG. 1 is connected to a steering wheel (not shown) of a vehicle and an input shaft 2 via a torsion bar 6. The output shaft 3 is provided.
The torsion bar 6 is connected to the input shaft 2 via a pin 4 and is connected to the output shaft 3 via a serration 5. The input shaft 2 is supported by a valve housing 7 via a bearing 8, and the output shaft 3 is supported via a bearing 12.
It is supported by. The output shaft 3 is a bearing 1
It is rotatably supported by the rack housing 9 via 0 and 11. A pinion 15 is formed on the output shaft 3, and a steering wheel (not shown) is connected to a rack 16 that meshes with the pinion 15. As a result, the rotation of the input shaft 2 due to steering is transmitted to the pinion 15 via the torsion bar 6, the rotation of the pinion 15 moves the rack 16 in the vehicle width direction, and the movement of the rack 16 causes steering of the vehicle. Done. Oil seals 47 and 48 are interposed between the input / output shafts 2 and 3 and the valve housing 7. In addition, the support yoke 4 that supports the rack 16
0 is pressed against the rack 16 by the elastic force of the spring 41.

A hydraulic cylinder 20 is provided as a hydraulic actuator that applies a steering assist force. The hydraulic cylinder 20 includes a cylinder tube configured by the rack housing 9 and a piston 21 integrated with the rack 16. A rotary hydraulic control valve 30 is provided in order to supply pressure oil to the oil chambers 22 and 23 partitioned by the piston 21 according to the steering direction and steering resistance.

The control valve 30 is a tubular first valve 31 rotatably inserted in the valve housing 7.
And a second valve 32 which is inserted into the first valve 31 so as to be rotatable relative thereto. The first valve 31
Is connected to the output shaft 3 via a pin (not shown) so as to rotate together. The second valve 32 is formed integrally with the input shaft 2, and the outer peripheral portion of the input shaft 2 serves as the second valve 32, whereby the second valve 32 rotates together with the input shaft 2.

In the valve housing 7, a pump port 34 connected to a pump 42, a tank port 36 connected to a tank 43, and a first port 37 connected to one oil chamber 22 of the hydraulic cylinder 20. , The other oil chamber 2
And a second port 38 connected to port 3. Each port 34, 36, 37, 38 has its first valve 31
And the second valve 32 are communicated with each other via an intervalve passage 27 formed between them. The throttling degree of the inter-valve passage 27 changes due to the relative rotation of the input / output shafts 2 and 3 due to the torsion of the torsion bar 6 due to the steering resistance.

That is, as shown in FIG. 2, a plurality of first valve-side recesses 50 are formed in the inner circumference of the first valve 31 at equal intervals in the circumferential direction, and a plurality of second recesses 50 are formed on the outer circumference of the second valve 32. The valve-side recessed portions 51 are formed at equal intervals in the circumferential direction. In the first valve-side recessed portion 50, one communicating with the first port 37 and one communicating with the second port 38 are alternately arranged in parallel along the circumferential direction, and the second valve-side recessed portion 51 has the first valve-side recessed portion 51. The one communicating with the pump port 34 and the one communicating with the tank port 36 through the space between the inner and outer circumferences of the torsion bar 6 and the input shaft 2 are alternately arranged in parallel along the circumferential direction. The circumferential portions between the edge of the first valve-side concave portion 50 along the axial direction and the edge of the second valve-side concave portion 51 along the axial direction are narrowed portions A, B, C, and D.
FIG. 2 shows a state in which steering is not performed. The pump port 34 and the tank port 36 communicate with each other through the intervalve passage 27, and the oil flowing from the pump 42 into the control valve 30 flows back to the tank 43 to assist steering. No force is generated. Steering resistance generated by steering to the left or right from this state causes the first valve 31 and the second valve 3 together with the input / output shafts 2 and 3.
When 2 relatively rotates, the opening degree of the throttle portion A between the pump port 34 and the first port 37 increases, and the opening degree of the throttle portion B between the first port 37 and the tank port 36 decreases. The opening degree of the throttle portion C between the pump port 34 and the second port 38 decreases, and the opening degree of the throttle portion D between the second port 38 and the tank port 36 increases. As a result, the pressure oil having a pressure corresponding to the steering direction and the steering resistance is supplied to one oil chamber 22 of the hydraulic cylinder 20, and the oil flows back from the other oil chamber 23 to the tank 43 to the left or right of the vehicle. The steering assist force of the above acts on the rack 16 from the hydraulic cylinder 20. In addition, when steering to the other left or right, the first valve 31
Since the second valve 32 and the second valve 32 relatively rotate in the opposite direction to the case of steering to the left or right, the openings of the throttles A, B, C, and D are also opposite to the case of steering to the left or right, and The steering assist force to the other acts on the rack 16 from the hydraulic cylinder 20.

As shown in FIGS. 1 and 3, the pump 42
A regulation means 45 for regulating the twist of the torsion bar 6 is provided by the action of the hydraulic pressure of the pressure oil delivered from the. The restricting means 45 has a plurality of guide holes 52 formed in the output shaft 3 and a plunger 53 movably inserted in the radial direction of the output shaft 3. Each plunger 5
The tip of 3 is in contact with the outer circumference of the input shaft 2. Sealing members 55 and 56 that seal the output shaft 3 and the valve housing 7 in an oil-tight manner are provided at the upper and lower positions of each plunger 53 in FIG. As a result, an oil chamber 57 is formed between the seal members 55 and 56 in the axial direction.
The oil chamber 57 has a valve device 60 at the pump port 34.
Connected via. As a result, the hydraulic pressure is applied to each plunger 5
When acting on 3, the plungers 53 move inward in the radial direction of the output shaft 3 to press the input shaft 2 and regulate the relative rotation between the input shaft 2 and the output shaft 3.

As shown in FIGS. 1 and 4, the valve device 60 is inserted into the sleeve holding hole 63 formed in the valve housing 7 and the holding hole 63 so as not to rotate relative to each other, for example, by being press-fitted. A sleeve 61 and a spool 62 inserted into a spool insertion hole 61a on the inner circumference of the sleeve 61. The spool 62 is rotatable relative to the sleeve 61, that is, the housing 7 side about its own axis. A pressure oil supply passage 64 that connects the sleeve holding hole 63 and the pump port 34 of the control valve 30, a pressure oil discharge passage 65 that connects the holding hole 63 and the tank port 36 of the control valve 30, and a holding hole thereof. A pressure oil introduction passage 66 that communicates 63 with the oil chamber 57 of the regulating means 45 is formed in the valve housing 7.
Further, as shown in FIG. 5, a drain oil discharge passage 83 that connects the pressure oil discharge passage 65 and the holding hole 63 is formed in the valve housing 7.

As shown in FIGS. 4 and 6, the sleeve 6 is
1, the first circumferential groove 7 communicating with the pressure oil supply passage 64
0 and a second circumferential groove 72 communicating with the pressure oil introduction passage 66 are formed. A pair of first pressure oil passages 73 on the housing 7 side that communicates the first circumferential groove 70 with the spool insertion hole 61a on the inner periphery of the sleeve 61, and a housing that communicates the second circumferential groove 72 with the insertion hole 61a. A pair of second pressure oil passages 75 on the seventh side are formed in the sleeve 61 along the radial direction. The two first pressure oil passages 73 are arranged 180 degrees apart from each other in the circumferential direction of the sleeve 61.
5 are arranged 180 degrees apart from each other in the circumferential direction of the sleeve 61. The opening 73a of each first pressure oil passage 73 in the inner periphery of the insertion hole 61a is circular when viewed from one direction orthogonal to the axis of the spool 62, as shown in (2) of FIG. The opening 73a can be closed by a closing surface 62a formed along a cylindrical surface formed by a part of the outer peripheral surface of the spool 62. The closing area of each opening 73a by the closing surface 62a is determined by the sleeve 61 of the spool 62.
Changes based on relative rotation with respect to.

A part of the outer peripheral surface of the spool 62 is a pair of flat surfaces 62b parallel to the axis of the spool 62.
Both planes 62b are arranged 180 degrees apart in the circumferential direction of the spool 62. Each flat surface 62b has a pair of edges 62b 'parallel to each other along the axial direction of the spool 62 and a pair of parallel edges 62b "parallel to the radial direction. Each flat surface 62b has a pair of edges along the axial direction. 62b 'and a step 62 that is continuous with the edge 62b "along one radial direction on the lower side in the drawing.
c and a peripheral groove 80 which is continuous with the other radial edge 62b ″ on the upper side in the drawing, and is partitioned from the closing surface 62a. The step 62c is closed by an outer edge 62c ′ along the circumferential direction. The spool 62 is defined between each flat surface 62b and the inner peripheral surface of the insertion hole 61a of the sleeve 61.
Side third pressure oil passage 81, and the third pressure oil passage 81 is connected to the second pressure oil passage 7 on the housing side through the circumferential groove 80.
Connect to 5.

A fourth pressure oil passage 77 is formed in the spool 62 along the radial direction, and a drain passage 78 that connects the fourth pressure oil passage 77 to one axial outside of the spool 62 is provided with a drain passage 78. It is formed along the heart. The drain passage 78 has a small diameter and thus functions as a fixed throttle. The pressure oil discharge passage 65 is connected to the holding hole 63 at one axial outer side of the spool 62.

Edges 62b 'along the axial direction of the planes 62b of the spool 62 and outer edges 62c' of the steps 62c.
And an area surrounded by the periphery of the opening 73a of each of the first pressure oil passages 73 is a throttle portion of the pressure oil between the first pressure oil passage 73 and the third and fourth pressure oil passages 81 and 77. Has been done.
The opening area of the narrowed portion is the closing surface 6 of each opening 73a.
The closed area by 2a changes by changing based on the relative rotation of the spool 62 with respect to the housing 7 side.

As shown in FIG. 4, a stepping motor 90 is attached to the valve housing 7. The output shaft of the motor 90 is parallel to the shaft center of the spool 62,
As shown in FIG. 14, the second reduction gear 92b is integrated with the first reduction gear 92a that meshes with the pinion 91 attached to the output shaft of the second reduction gear 92b.
The third reduction gear 93 attached to the spool 62 meshes with the. The motor 90 is controlled by a control device 94 having a vehicle speed sensor.

FIG. 8 (2) shows the relative positional relationship between the opening 73a of the first pressure oil passage 73 and the flat surface 62b of the spool 62 in the rotation step of the stepping motor 90 (one step is relative to the housing side of the spool 62). It corresponds to the unit relative rotation angle, and the rotation step increases as the vehicle speed increases). In the figure, the left-right direction is the circumferential direction of the spool 62, and the up-down direction is the axial direction of the spool 62. The position of the outer edge 62c 'of the step 62c forming the throttle portion of the pressure oil between the first pressure oil passage 73 and the third and fourth pressure oil passages 81 and 77, and the opening 7 thereof.
The center position of 3a coincides with the axial direction of the spool 62. The narrowed portion is shown by hatching.

FIG. 6 (1) shows a low speed state or a stopped state. In this state, the throttle portion between the first pressure oil passage 73 and the third and fourth pressure oil passages 81 and 77 is fully closed, Pressure oil supply passage 64 communicating with pump port 34 and regulating means 45
The pressure oil introducing passage 66 communicating with the oil chamber 57 is closed. Therefore, since the plunger 53 of the regulating means 45 does not press the input shaft 2, the input shaft 2 and the output shaft 3
Relative rotation with is not regulated. As a result, as shown in FIG. 7, the increase rate of the hydraulic pressure that generates the steering assist force with respect to the steering input torque is increased, and the high responsiveness of steering is satisfied.

FIG. 6B shows a state in which the vehicle speed is higher than that in the low speed state. The increase in the vehicle speed increases the rotation step of the stepping motor 90, and the spool 6
The spool 62 is rotated by the relative rotation of the second sleeve 61.
Rotates relative to the housing side. As a result, FIG.
As shown in (2) of No. 1, the first pressure oil passage 73 and the third, fourth
The opening area of the throttle portion between the pressure oil passages 81 and 77 increases according to the number of steps. Therefore, as the vehicle speed increases, the hydraulic pressure with which the plunger 53 of the restricting means 45 presses the input shaft 2 increases, and the twisting force of the torsion bar 6 due to the steering resistance increases. Relative rotation with the output shaft 3 is restricted. As a result, at a high speed, as shown in FIG. 7, the increase rate of the hydraulic pressure for generating the steering assist force with respect to the steering input torque decreases, and the steering stability is satisfied. Also,
During medium-speed traveling, higher steering response is achieved than during high-speed traveling, and steering stability is better than during low-speed traveling.

In FIG. 9, the alternate long and short dash line shows the relationship between the rotation step of the spool and the opening area of the throttle portion in the conventional example shown in FIG. 8 (1), and the solid line in this embodiment in FIG. 8 (2). The relationship between the rotation step of the spool and the opening area of the throttle is shown. The spool diameter, the opening diameter of the housing-side pressure oil passage, and the unit rotation amount per step of the spool are the same in the conventional example and the present example. From this, it can be confirmed that according to this embodiment, the amount of change in the opening area of the throttle portion per unit relative rotation amount with respect to the housing of the spool can be made smaller than in the conventional case.

According to the above construction, the opening area change amount of the throttle portion per unit relative rotation amount of the spool 62 with respect to the housing side is determined by the axial difference between the step 62c of the spool 62 and the opening 73a of the first pressure oil passage 73. It can be set according to the position. Therefore, the opening area change amount of the throttle portion per unit relative rotation amount of the spool 62 with respect to the housing side can be reduced without reducing the area of the opening 73a and the radial dimension of the flat surface 62b. As a result, even if the rotation angle of the spool 62 per step of the stepping motor 90 is large, the amount of change in the opening area of the throttle portion per step is small, and the steering assist force changes abruptly due to changes in vehicle speed. Therefore, there is no problem that the steering feeling is deteriorated. Moreover, since it is not necessary to increase the reduction ratio of the stepping motor 90, the size of the device does not increase. Further, since the spool-side pressure oil passage is formed between the outer peripheral flat surface 62b of the spool 62 and the inner peripheral surface of the insertion hole 61a, the spool-side pressure oil passage is constituted by the spool through hole as in the conventional case. In comparison with the case, if the radial dimension of the flat surface 62b and the diameter of the through hole are the same, the passage area of the pressure oil passage on the spool side can be reduced. With this, by reducing the passage area of the pressure oil passage on the spool side, it is possible to prevent the passage area of the pressure oil that has passed through the throttle portion from rapidly expanding, and it is possible to prevent bubbles from being generated in the pressure oil. It can prevent and reduce the flow noise. Moreover, the radial dimension of the flat surface 62b can be made sufficiently large to prevent the adjustable range of the aperture of the throttle portion from being narrowed. Further, since the two throttle portions are provided at equal intervals in the circumferential direction of the spool 62, the hydraulic pressure acting in the radial direction on the spool 62 is balanced, and the closing surface 62 a of the spool 62 and the insertion hole 61.
It is possible to prevent the inner peripheral surface of a from being twisted.

10 and 11 show a second embodiment of the present invention. In the second embodiment, the spool 62 is the same as in the first embodiment.
A through hole 95 is formed in the output shaft 3 along the radial direction in place of the fourth pressure oil passage 77 and the drain passage 78 having a throttling function which are formed on the output shaft 3. One end of the through hole 95 has a regulation means 4
5 to the oil chamber 57. The other end of the through hole 95 communicates with the tank port 36 from the gap between the input shaft 2 and the output shaft 3 through the space between the inner and outer circumferences of the input shaft 2 and the torsion bar 6. The other end 95a of the through hole 95 functions as a fixed diaphragm by having a small diameter. Others are the same as those in the first embodiment, and the same portions are denoted by the same reference numerals. According to this 2nd Example, the same effect as a 1st Example can be exhibited.

12 and 13 show a third embodiment of the present invention. In the third embodiment, the spool 62 is the same as in the first embodiment.
In place of the fourth pressure oil passage 77 and the drain passage 78 having a throttle function, the outer peripheral surface of the spool 62 is
It is a pair of second flat surfaces 62e parallel to the flat surface 62b. Each second flat surface 62e has a pair of edges 62e 'which are parallel to each other along the axial direction of the spool 62 and a pair of edges 62e "which are parallel to each other along the radial direction, and the pair of edges 62e' along the axial direction. The second flat surface 62e is defined by 1 in the circumferential direction of the spool 62.
They are placed 80 degrees apart. The distance from the axis of the spool 62 to each second flat surface 62e is larger than that to the flat surface 62b. The step 62c of the first embodiment is separated from the closed surface 62a by the outer edge 62c 'along the circumferential direction.
The outer edge of the step 62c of the second embodiment is the second plane 62e.
The edge 62e ″ along the upper radial direction in the figure corresponds to the outer edge 62e ″, which divides the second plane 62e from the plane 62b. An edge 62e ″ of each second flat surface 62e extending along the lower radial direction in the drawing defines the second flat surface 62e and the lower end surface of the spool 62 in the drawing.
2e and the inner peripheral surface of the insertion hole 61a of the sleeve 61,
A drain passage having a throttle function leading to the pressure oil passage on the spool side is configured. Others are the same as those in the first embodiment, and the same portions are denoted by the same reference numerals. According to the third embodiment, the same operational effect as the first embodiment can be obtained. Moreover, the first
As compared with the embodiment in which the small diameter hole formed in the spool 62 is used as the drain passage 78 to accurately finish the inner diameter, the drain passage is provided between the second flat surface 62e and the inner peripheral surface of the insertion hole 61a. Since it is easier to finish the dimensions with high precision, the processing cost can be reduced.

In each of the above embodiments, the adjusting screw 96 is screwed into the valve housing 7 as shown in FIG. 14 in order to adjust the reference opening degree of the throttle portion of the pressure oil. That is, the third reduction gear 93 has a cutout portion 93a in a part of the outer periphery thereof, and the contact position between one end of the cutout portion 93a and the tip of the adjusting screw 96 is the meshing reference position. The position where the output shaft of the motor 90 rotates from the meshing reference position by a certain number of steps is set as the control reference position. Starting from the control reference position, the output shaft of the motor 90 rotates by the number of steps corresponding to the vehicle speed. By changing the screwing amount of the adjusting screw 96 into the valve housing 7, the meshing reference position changes, and the reference opening of the throttle portion can be adjusted. In addition, the first reduction gear 92a
The support shaft 92c of the second reduction gear 92b is inserted into a long hole 97 formed in the valve housing 7 so as to be movable in the longitudinal direction, and the support shaft 9c in the long hole 97 is inserted.
A second adjusting screw 98 along the radial direction of 2c is screwed into the valve housing 7, and a spring 98 is interposed between the second adjusting screw 98 and the support shaft 92c. As a result, backlash between the pinion 91 and the reduction gears 92a, 92b, 93 is eliminated, and when the output shaft of the motor 90 rotates forward and backward, the spool 62 rotates regardless of the rotation of the pinion 91. It is possible to prevent a situation such as not doing so and obtain proper steering characteristics.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the position of the outer edge 62c 'of the step 62c and the center position of the opening 73a are determined by the spool 6
Although they coincide with each other with respect to the two axial directions, they may deviate from each other. Further, although the spool 62 is rotationally controlled according to the vehicle speed in the above embodiment, it may be controlled according to other operating conditions such as the steering angle. Further, the present invention can be applied not only to the valve device used in the hydraulic power steering device but also to any valve device in which the opening area of the throttle portion can be changed by the relative rotation of the sleeve with respect to the housing side.

[0040]

According to the valve device of the present invention, the opening area change amount of the throttle portion per unit relative rotation amount with respect to the housing side of the spool can be reduced without increasing the size of the device, and the pressure oil The flow noise can be reduced, and the drain passage having the throttle function can be provided at low cost. According to the hydraulic power steering device using the valve device of the present invention, steering feeling can be improved.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view of a control valve in the hydraulic power steering system according to the first embodiment.

FIG. 3 is a transverse cross-sectional view of a restricting unit in the hydraulic power steering device according to the first embodiment.

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

5 is a sectional view of the valve housing taken along the line VV in FIG.

6A and 6B are a cross-sectional view of the valve device according to the first embodiment in a low speed state, FIG. 6B is a cross-sectional view of the valve device in a high-speed state, and FIG.

FIG. 7 is a diagram showing a relationship between input torque and hydraulic pressure.

FIG. 8 (1) is an operation explanatory view of a conventional valve device,
(2) is an explanatory view of the operation of the valve device according to the embodiment of the present invention

FIG. 9 is a diagram showing the relationship between the number of rotation steps of the spool and the opening area of the throttle portion.

FIG. 10 is a sectional view of essential parts of a hydraulic power steering device according to a second embodiment of the present invention.

FIG. 11 is a transverse cross-sectional view of a restricting unit in the hydraulic power steering device according to the second embodiment.

FIG. 12 is a sectional view of essential parts of a hydraulic power steering device according to a third embodiment of the present invention.

FIG. 13 (1) of the valve device of the third embodiment is a transverse sectional view in a low speed state, (2) is a transverse sectional view in a high speed state, and (3).
Is a vertical sectional view of the main part

FIG. 14 is a partial horizontal sectional view of the valve device according to the embodiment of the present invention, and FIG. 14 is a partial vertical sectional view thereof.

FIG. 15 is a partial sectional view of a conventional hydraulic power steering device.

[Explanation of symbols]

2 input axes 3 output axes 7 Valve housing 30 control valve 45 Regulation means 60 valve device 61a insertion hole 62 spool 62a closed surface 62b plane 62b 'edge along the axial direction 62b ″ Radial edge 62c step 62c ', 62e "outer edge 62e Second plane 73 First pressure oil passage 73a opening 81 Third pressure oil passage 90 stepping motor 94 Control device

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-63-242775 (JP, A) JP-A-55-11907 (JP, A) JP-A-61-132466 (JP, A) JP-A-6- 179370 (JP, A) Actual opening 2-11773 (JP, U) Actual opening 62-23171 (JP, U) Actual opening 64-34376 (JP, U) Actual opening 5-12859 (JP, U) Japanese Patent Publication No. 5-61505 (JP, B2) S. 62-46004 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB name) B62D 5/00-5/30 F16K 3/24 F16K 3/26 F16K 3/32 F16K 5/04

Claims (3)

(57) [Claims] 1. A housing, and a spool inserted into an insertion hole formed on the housing side, the spool being rotatable relative to the housing side about its own axis, the housing side and the spool side. And a pressure oil passage is formed in the housing, and the housing-side pressure oil passage has an opening in the inner periphery of the insertion hole, and the opening can be closed by a closing surface formed by a part of the outer peripheral surface of the spool. , Part of the outer peripheral surface of the spool is
The flat surface is a concave surface, and the flat surface has a pair of edges along the axial direction of the spool and one end of each of the pair of edges as both ends.
A rim along a radial direction of the spool as well as possess, constitutes the pressure oil passage of the spool-side between the inner peripheral surface of the planar insertion hole, the plane is recessed from the outer peripheral surface of the spool
As a result, a step is formed that is continuous with the edge along the radial direction.
Edge along the axial direction of the plane of the
A region surrounded by an outer edge along the outer periphery of the roll and a peripheral edge of the opening is a throttle portion of the pressure oil between the housing side pressure oil passage and the spool side pressure oil passage, and the closing area of the opening by the closing surface is A valve device in which the opening area of the throttle portion is variable by changing based on the relative rotation of the spool with respect to the housing side. 2. A part of the outer peripheral surface of the spool is a second plane parallel to the plane, and the second plane has a greater distance from the axis of the spool than the plane, and the second plane and the The flat surface is defined by the outer edge of the step, and the second flat surface and the inner peripheral surface of the insertion hole communicate with the pressure oil passage on the spool side and form a drain passage having a throttle function. The valve device described. 3. An input / output shaft that relatively rotates according to steering resistance,
In a hydraulic power steering device including a rotary control valve that controls the hydraulic pressure for generating steering assist force according to the relative rotation amount of the input / output shaft, and a regulating unit that regulates the relative rotation of the input / output shaft according to the hydraulic pressure, The hydraulic pressure acting on the regulating means can be adjusted by squeezing the pressure oil by the valve device according to claim 1, and a control device for relatively rotating the spool relative to the housing side by a stepping motor according to operating conditions is provided. Hydraulic power steering device provided.