JP2589451Y2 - 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 hydraulic power steering apparatus having a control valve for controlling a steering assist force according to a relative rotation amount between an input shaft and an output shaft.

[0002]

2. Description of the Related Art An input shaft rotated by steering, an output shaft connected to the input shaft via a torsion bar, and a control valve for steering assist force control are provided on the outer periphery of the input shaft. It has a cylindrical valve member fitted so as to be rotatable relative to the output shaft and rotatably fitted with the outer periphery of the output shaft, and an opening degree of a throttle portion formed between the valve member and the input shaft is reduced. 2. Description of the Related Art A hydraulic power steering device in which a steering assist force is controlled by changing according to a relative rotation amount between an input shaft and an output shaft has been conventionally used.

As shown in FIG. 5, in a conventional control valve, a pin insertion hole 102 formed in a valve member 101 along a radial direction and a pin insertion hole 104 formed in an output shaft 103 along a radial direction. Dowel Pin 105
Is inserted, the valve member 101 and the output shaft 103 rotate together.

The connection between the valve member 101 and the output shaft 103 by the pin 105 is performed by inserting the pin 105 into the pin insertion holes 102 and 104 after fitting the valve member 101 to the output shaft 103. Since it is difficult to re-disassemble the valve member 101 and the output shaft 103 in the assembly process due to relative position adjustment, first, the pin 105 is pressed into the pin insertion hole 104 of the output shaft 103, and then the output shaft is The valve member 101 is fitted to the valve shaft 103, and then the valve member 101 is displaced in the radial direction with respect to the output shaft 103, so that the pin 105 is inserted into the pin insertion hole 102 of the valve member 101. In this case, the fitting of the pin 105 into the pin insertion hole 102 of the valve member 101 is a loose fit.

Since the pin 105 must be inserted into each of the pin insertion holes 102 and 104 in the above-described operation procedure, the valve member 10
1, the outer diameter of the fitting portion of the output shaft 103 with the valve member 101 is D1 ', the protrusion of the pin 105 from the output shaft 103 is L, the valve is Assuming that the outer diameter of the member 101 is D4, D2> D1 '+ L and D4
> D1 '+ 2L> D2.

[0006]

In the above-described hydraulic power steering apparatus, it is desired that the outer diameter D4 of the valve member 101 be as small as possible in order to reduce the size and weight. Further, in order to increase the radial contact length between the valve member 101 and the pin 105 to secure the connection between the valve member 101 and the output shaft 103, the output shaft 1 of the valve member 101
It is desired to reduce the inner diameter D2 of the fitting portion with the smallest possible.

However, the outer diameter D4 and the inner diameter D of the valve member 101 are different.
2 to reduce the outer diameter D1 ′ of the output shaft 103.
Must be reduced, and the strength of the output shaft 103 is reduced. In particular, as shown in FIG. 6, a concave portion 103a is formed at the shaft end of the output shaft 103, and this concave portion 10a is formed.
Non-circular portion 1 formed on the outer surface of input shaft 106 on the inner surface of 3a
06a and the input shaft 106 and the output shaft 103
Torsion bar 1
In the case of preventing the breakage of the recess 07, the thickness around the concave portion 103a becomes thin, so that the strength is reduced. Therefore, the strength of the concave portion 103a is improved by enclosing the entire periphery with a wall, but if such a shape is used, machining is difficult and forging must be performed, thereby increasing the processing cost. was there.

An object of the present invention is to provide a hydraulic power steering device that can solve the above-mentioned problems of the prior art.

[0009]

SUMMARY OF THE INVENTION The present invention comprises an input shaft rotated by steering, an output shaft connected to the input shaft via a torsion bar, and a control valve for steering assist force control. Has a cylindrical valve member fitted to the outer periphery of the input shaft so as to be relatively rotatable and fitted to rotate together with the outer periphery of the output shaft, and formed between the valve member and the input shaft. The steering assisting force is controlled by changing the opening degree of the throttle portion according to the relative rotation amount between the input shaft and the output shaft, and a pin insertion hole along the radial direction formed on the valve member and the output shaft. In a hydraulic power steering device in which a pin is inserted into the valve member and the output shaft rotates together, in the inner periphery of a fitting portion of the valve member with the output shaft,
A step is formed such that the portion closer to the axial end is thinner than the portion closer to the center in the axial direction, and the step separates the pin insertion hole of the valve member into a portion closer to the axial end and a portion closer to the axial center. A pin protruding from the output shaft can be fitted in the axially central portion of the pin insertion hole of the valve member from the axial direction, and the inner diameter of the axially central portion of the fitting portion of the valve member with the output shaft is fitted. D2, δ> D1 + L and D1 + 2, where D2 is the outer diameter of the fitting portion of the output shaft with the valve member, D is the projection of the pin from the output shaft, and δ is the step size.
L> D2 + 2δ.

[0010]

According to the structure of the present invention, the pin is press-fitted into the pin insertion hole of the output shaft, and then the valve member is fitted to the output shaft in the axial direction. The pin protruding from the output shaft can be fitted from the axial direction. Thereafter, the pin can be inserted into the pin insertion hole of the valve member by displacing the valve member in the radial direction with respect to the output shaft.

On the inner periphery of the fitting portion of the valve member with the output shaft,
A step is formed such that the portion closer to the axial end is thinner than the portion closer to the center in the axial direction, and the step separates the pin insertion hole of the valve member into a portion closer to the axial end and a portion closer to the axial center. Therefore, the outer diameter of the output shaft can be made larger by the step size δ than in the case where there is no step. In addition, the radial contact length between the pin portion of the valve member near the axial center of the pin insertion hole and the pin does not become short even if there is a step.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

A rack and pinion type hydraulic power steering device 1 shown in FIG. 1 has a cylindrical input shaft 2 connected to a steering wheel (not shown) of a vehicle, and an output connected to the input shaft 2 via a torsion bar 6. The input shaft 2 and the output shaft 3 rotate relative to each other by the torsion of the torsion bar 6. That is, the input shaft 2 and the output shaft 3 are concentric, and the lower end of the input shaft 2 is smaller in diameter than the upper portion.
A concave portion 3a is formed at the upper end of the output shaft 3 opposite to the lower end of the output shaft. The lower end of the input shaft 2 is fitted in the recess 3a with the bearing 1
2 are fitted. A torsion bar 6 is inserted into the input shaft 2 and the output shaft 3.
The upper end is connected to the input shaft 2 via a pin 4, and the lower end is connected to the output shaft 3 via a serration 5.

The input shaft 2 is rotatably supported by a valve housing 7 via a bearing 8. The output shaft 3 has a pair of bearings 1 mounted on a rack housing 9.
It is rotatably supported via 0,11. A pinion 15 is formed on the output shaft 3, and a rack 16 meshing with the pinion 15 is supported by a support yoke 40.
Steering wheels (not shown) are connected to the rack 16. Thus, the rotation of the input shaft 2 due to the steering is transmitted to the pinion 15 via the torsion bar 6, and the rotation of the pinion 15 causes the rack 16 to move in the vehicle width direction.
The vehicle is steered by the movement of the rack 16.

A hydraulic cylinder 20 is provided as a hydraulic actuator for applying 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. Hydraulic control valves 30 for supplying hydraulic oil in accordance with the steering direction and the steering resistance are provided in oil chambers 22 and 23 partitioned by the piston 21.

The control valve 30 is inserted into the valve housing 7 through a plurality of upper and lower seal rings 25 so as to be relatively rotatable, and is fitted to the outer periphery of the input shaft 2 so as to be relatively rotatable. A valve member 31 is provided. The valve member 31 is provided with a pin 3 on the outer periphery of the output shaft 3.
2 so as to rotate together. That is, as shown in FIG. 2, the output shaft 3 and the valve member 31 are provided with pin insertion holes 41 and 42 extending in the radial direction, respectively, and the pins 32 are inserted into the both pin insertion holes 41 and 42. . The pin 32 is pressed into the pin insertion hole 41 of the output shaft 3, and the fitting of the valve member 31 into the pin insertion hole 42 is a loose fit.

The fitting portion 31 of the valve member 31 with the output shaft 3
A step 31b is formed on the inner periphery of a so that the portion closer to the axial end (the lower portion in FIG. 2) is thinner than the portion closer to the axial center (the upper portion in FIG. 2). In this embodiment, the step 31 b is formed over the entire inner circumference of the valve member 31. Due to the step 31b, the pin insertion hole 42 of the valve member 31 is shifted toward the axial end portion 42.
a and an axially central portion 42b. In the present embodiment, the step 31b is disposed at the center of the pin insertion hole 42, and thereby the pin insertion hole 4
The pin 32 protruding from the output shaft 3 can be fitted in the axially central portion 42b of the second shaft 2 in the axial direction.

The fitting portion 31 of the valve member 31 to the output shaft 3
The inner diameter of the portion near the end in the axial direction of D is D3, the inner diameter of the portion near the center in the axial direction is D2, the outer diameter of the fitting portion 3b of the output shaft 3 with the valve member 31 is D1, Assuming that the protruding dimension is L, the outer diameter of the valve member 31 is D4, and the dimension of the step 31b is δ = (D3-D2) / 2, D2 + (D3-D
2) / 2> D1 + L and D1 + 2L> D2 + 2δ. Thereby, after the pin 32 is pressed into the pin insertion hole 41 of the output shaft 3, the valve member 31 is fitted to the output shaft 3 from the axial direction (from above in FIG. 2).
The pin 32 protruding from the output shaft 3 can be fitted in the axially central portion 42b of the one pin insertion hole 42 from the axial direction. Thereafter, by displacing the valve member 31 in the radial direction with respect to the output shaft 3, the pin insertion hole 4 of the valve member 31 is formed.
2, the pin 32 can be inserted to connect the valve member 31 and the output shaft 3.

As shown in FIG. 3, the concave portion 3a formed at the upper end of the output shaft 3 is formed into a groove shape having left and right walls and open up and down in the figure. . By contacting the outer surface of the non-circular portion 2a formed on the outer periphery of the input shaft 2 with the inner surface of the concave portion 103a,
The relative rotation amount between the input shaft 2 and the output shaft 3 is regulated within a certain range, thereby preventing the torsion bar 6 from being damaged.

The valve housing 7 has an inlet port 34 connected to a pump 33, an outlet port 36 connected to a tank 35, and a first port 37 connected to one oil chamber 22 of the hydraulic cylinder 20. , A second port 38 connected to the other oil chamber 23. The ports 34, 36, 37, and 38 communicate with each other through an oil passage between the input shaft 2 and the valve member 31, and the throttle formed in the oil passage is connected to the input shaft 2 due to the torsion bar 6 being twisted. The opening is adjusted by the relative rotation between the valve member 31 and the valve member 31.

That is, as shown in FIG.
The first concave portions 50 along the axial direction on the inner periphery of the
It is formed at several places. Eight second concave portions 51 are formed at equal circumferential intervals on the outer periphery of the input shaft 2 so as to oppose the first concave portions 50 in the circumferential direction. The first recess 50 is connected to the first port 3 through a flow path 53 formed in the valve member 31.
7 and a flow path 54 formed in the valve member 31.
Are alternately arranged in the circumferential direction in parallel with the second port 38. The second recess 51 is formed between the torsion bar 6 and the input shaft 2 through the flow passage 52 a formed below the input shaft 2 and the one communicating with the inlet port 34 via the flow passage 55 formed in the valve member 31. The one that communicates with the outlet port 36 from the flow path 52b formed above the input shaft 2 via the flow path 52c between the inner and outer circumferences is alternately arranged in the circumferential direction. Apertures A, B, C, and D are defined between circumferential edges of the first recess 50 along the axial direction and the second recess 51 along the axial direction. FIG. 4 shows a state where steering is not performed. The inlet port 34 and the outlet port 36 communicate with each other, the oil flowing from the pump 33 into the control valve 30 is returned to the tank 35, and no steering assist force is generated. When the torsion bar 6 is twisted due to steering resistance generated by steering to the left or right, and the valve member 31 and the input shaft 2 rotate relative to each other, the relative position between the first concave portion 50 and the second concave portion 51 changes, and the inlet port 34 is changed. The opening degree of the throttle A between the first port 37 and the first port 37 increases, the opening degree of the throttle B between the first port 37 and the outlet port 36 decreases, and the inlet port 34 and the second port 38 , The opening degree of the throttle portion C between the second port 38 and the outlet port 36 increases. As a result, 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 to the tank 35 from the other oil chamber 23 and to one of the left and right sides of the vehicle. Is applied from the piston 21 to the rack 16. When the vehicle is steered to the left or right, the valve member 31 and the input shaft 2 rotate relative to each other in a direction opposite to the direction in which the vehicle is steered to the left or right.

The hydraulic oil of the hydraulic cylinder 20 is pump 3
While returning to the tank 35 from the valve housing 7, the valve housing 7
The oil seal 60 is interposed between the outer circumference of the input shaft 2 and the upper inner circumference of the valve housing 7, and is interposed between the outer circumference of the output shaft 3 and the lower inner circumference of the valve housing 7 in order to prevent leakage. An oil seal 61 is provided between the upper outer periphery of the torsion bar 6 and the upper inner periphery of the input shaft 2.

According to the above configuration, the output shaft 3 of the valve member 31
A step 31b is formed on the inner periphery of the fitting portion 31a so that a portion closer to the axial end is thinner than a portion closer to the center in the axial direction, and the pin insertion hole 42 of the valve member 31 is formed by the step 31b. The step 31b is divided into a part 42a near the axial end and a part 42b near the center in the axial direction, so that the step 31b has a radial dimension (D3-D2) / 2 = δ of the step 31b.
The outer diameter D1 of the output shaft 3 can be increased as compared with the case where there is no. In addition, the radial contact length between the pin 32 and the pin 32 near the axial center of the pin insertion hole 42 of the valve member 31 does not become short even if the step 31b exists. Accordingly, the diameter of the fitting portion 3b of the output shaft 3 with the valve member 31 can be increased without increasing the size of the steering device and without reducing the connection strength between the valve member 31 and the output shaft 3. Strength can be improved. Also, input shaft 2
The concave portion 3a formed in the output shaft 3 for regulating the relative rotation amount between the shaft 3 and the output shaft 3 can be easily machined without having to surround the entire periphery with a wall, so that the processing cost can be reduced.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the step 31b is provided over the entire inner circumference of the valve member 31, but may be formed only on a part in the circumferential direction. Further, the step 31b of the above embodiment is used.
Is disposed at the center of the pin insertion hole 42, but if the pin 32 protruding from the output shaft 3 can be fitted in the axial center portion 42b of the pin insertion hole 42 from the axial direction, The position may be slightly shifted up and down.

[0025]

According to the hydraulic power steering device of the present invention, the valve member of the output shaft can be used without increasing the size of the steering device and reducing the connection strength between the valve member of the control valve and the output shaft. The diameter of the fitting portion can be increased to increase the strength, and the concave portion formed on the output shaft to regulate the relative rotation amount between the input shaft and the output shaft has a wall around the entire periphery. Since there is no need to surround, the shape can be easily machined, so that the processing cost can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a sectional view of a main part of the hydraulic power steering device according to the embodiment of the present invention;

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

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

FIG. 5 is a sectional view of a main part of a conventional hydraulic power steering device.

FIG. 6 is a sectional view taken along line VI-VI of FIG. 5;

[Explanation of symbols]

 2 input shaft 3 output shaft 6 torsion bar 30 control valve 31 valve member 31b step 32 pin 41 pin insertion hole 42 pin insertion hole A, B, C, D

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B62D 5/083

Claims (1)

(57) [Scope of request for utility model registration] An input shaft rotated by steering, an output shaft connected to the input shaft via a torsion bar, and a control valve for steering assist force control, the control valve being provided on the outer periphery of the input shaft. It has a cylindrical valve member fitted so as to be rotatable relative to the output shaft and rotatably fitted with the outer periphery of the output shaft, and an opening degree of a throttle portion formed between the valve member and the input shaft is reduced. The steering assist force is controlled by changing according to the relative rotation amount between the input shaft and the output shaft, and the pin is inserted into a radially extending pin insertion hole formed in the valve member and the output shaft. In a hydraulic power steering device in which a valve member and an output shaft rotate together, in the inner periphery of a fitting portion of the valve member with the output shaft, a portion closer to an axial end is thinner than a portion closer to an axial center. A step is formed in the valve, and the step The pin insertion hole of the member is divided into an axial end portion and an axial center portion, and a pin protruding from the output shaft can be fitted in the axial center portion of the valve member pin insertion hole from the axial direction. The inner diameter of the portion of the valve member fitting with the output shaft near the axial center is D2, the outer diameter of the fitting portion of the output shaft with the valve member is D1, and the pin protrudes from the output shaft. When the dimension is L and the step dimension is δ, D
A hydraulic power steering device, wherein 2 + δ> D1 + L and D1 + 2L> D2 + 2δ.