JPS6311191B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering device, and more particularly to a power steering device in which a control valve for controlling the supply and discharge of pressure fluid to and from a power cylinder is of a rotary type.

Rotary type control valves usually have a valve rotor that is integrally provided on the input shaft on the steering wheel side, and an output shaft on the steering wheel side that can rotate around the outer circumference of the valve rotor. When the valve sleeve is activated, pressure fluid is applied to the power cylinder depending on the direction of the relative rotational displacement from the neutral state caused between the input shaft and the output shaft, that is, between the valve rotor and the valve sleeve. Controls the direction of supply and discharge. Conventionally, the input shaft and the output shaft are connected via a torsion bar, and the torsion force of the torsion bar allows the valve rotor and valve sleeve to be maintained in a neutral state when the valve is not in operation. However, due to the structure of the torsion bar, when the torsion force in the left and right directions is zero, the valve rotor and valve sleeve must be in a neutral state. Therefore, in the torsion bar, a preload cannot be applied between the input and output shafts. was impossible.

For this reason, conventionally, in addition to or in place of the above-mentioned torsion bar, a C-shaped spring is used, for example, which is formed into a roughly C-shape by cutting out a part of a ring-shaped spring material, and the input shaft is connected between the notches of the C-shaped spring. A power steering device has been proposed in which a protrusion that is integrated with the output shaft is simultaneously clamped with a predetermined elastic force, thereby making it possible to maintain both shafts in a neutral state and at the same time apply preload. has been done. However, when applying such a C-shaped spring to a power steering device having a rotary type control valve,
In general, it is preferable to provide the protrusion at the butt part between the input shaft and the output shaft due to strength issues, and also because the valve sleeve integrated with the output shaft houses the input shaft and the valve rotor therein. ,
Conventionally, the C-shaped spring was housed within the valve sleeve, which had the disadvantage that the structure of that part was complicated and large.

In view of these drawbacks, the present invention provides a valve sleeve with a spring provided outside the valve sleeve, and furthermore, the spring can be placed at the abutting portion of the input shaft and the output shaft, which has excellent strength. The present invention provides a power steering device with a new configuration.

The present invention will be described below with reference to the illustrated embodiments.
In FIG. 1, the input shaft 1 and the output shaft 2 are arranged on the same axis, and the protrusion 3 protruding from the tip shaft of the input shaft 1 is fitted into the distal shaft of the output shaft 2. The input shaft 1 and the output shaft 2 are rotatably fitted into the bush 4, and in this state, the input shaft 1 and the output shaft 2 are rotatably supported in the housing 5 via a bearing 6. The input shaft 1 is linked to a steering wheel (not shown), while a helical pinion 7 is attached to the tip of the output shaft 2.
This pinion 7 is meshed with a rack that is linked to a steering wheel (not shown), similar to a conventionally known rack and pinion type power steering device.

As shown in FIGS. 1 to 3, a generally rectangular engaging portion 8 is located at the tip of the input shaft 1 in front of the protrusion 3.
However, the output shaft 2 is also formed with a groove 9 for receiving the engaging portion 8, and the engaging member 8 is disposed within the groove 9 with a required gap in the circumferential direction. Therefore, the input shaft 1 and the output shaft 2 can rotate relative to each other by an amount allowed by the gap therebetween. Protrusions 10 and 11 are provided in the vicinity of the engaging portion 8, that is, the input shaft 1, and the groove 9, that is, the output shaft 2, respectively. The notch 12a of the provided C-shaped spring 12 is held between both end surfaces. At this time, the circumferential interval (l) of the cutout portions 12a of the C-shaped spring 12 in the natural state is set smaller than the length of each protrusion 10, 11 in the same direction (see Fig. 2). By sandwiching both the protrusions 10 and 11 with this C-shaped spring 12, a desired preload can be applied between the input and output shafts 1 and 2. It goes without saying that when no external force is applied to the input/output shafts 1 and 2, the engaging portion 8 is held at a neutral position with respect to the rotational direction of the groove 9 by the C-shaped spring 12. Further, the C-shaped spring 12 is set so that the wall thickness becomes thicker toward the center, as shown in FIG. 3, so that the stress becomes uniform throughout.

However, the valve rotor 1 is connected directly to the input shaft 1.
3 is formed, and a valve sleeve 14 is rotatably fitted around the outer periphery of the valve rotor 13, basically forming a conventionally known rotary type control valve. The valve sleeve 14 needs to be integrally connected to the output shaft 2, and as described above, conventionally the valve sleeve 14 is connected to the output shaft 2 from outside so as to accommodate the projections 10, 11 and the C-shaped spring 12. However, in the present invention, the C-shaped spring 12 is connected to the output shaft 2 from inside. That is, as shown in FIG. 2, the end portion of the valve sleeve 14 on the output shaft 2 side is formed as a cylindrical portion 14a that can be fitted into the portion 2a of the output shaft 2 provided with the projection 11, and this cylindrical portion An axial engagement groove 15 having a width matching the circumferential width of the protrusion 11 and a through hole 16 that allows the protrusion 10 to pass therethrough and allow the protrusion 10 to be displaced in the circumferential direction are formed in 14a. The cylindrical portion 14a is located inside the C-shaped spring 12 as shown in FIGS. are integrally connected in the rotational direction, and the protrusion 10
pass through the through hole 16 with a predetermined interval at least on both sides in the rotational direction. In addition, the above C
The shaped spring 12 is held between a spacer 17 provided on the step 2b of the output shaft 2 and the step 14b of the valve sleeve 14.

In the neutral state, the control valve composed of the valve rotor 13 and the valve sleeve 14 simply circulates pressure fluid from a pump (not shown). That is, the pressure fluid from the pump is
As shown in the figure, the flow flows into an axial supply groove 23 formed in the valve rotor 13 through a supply hole 20 formed in the housing 5, an annular groove 21 formed in the valve sleeve 14, and a radial passage 22, and further flows into the axial supply groove 23 formed in the valve rotor 13. Axial grooves 24 and 25 are formed on the inner surface of the valve sleeve 14 so as to overlap both sides of the groove 23 in the circumferential direction, and the valve rotor 1 is formed so as to overlap both grooves 24 and 25.
3 into the axial discharge groove 26 formed at 3.
The pressure fluid that has flowed into the discharge groove 26 flows along the groove toward the butt part between the input shaft 1 and the output shaft 2, and from there flows through the through hole 16 and the notch 12a of the C-shaped spring 12. It flows out to the outer periphery of the valve sleeve 14, and further flows through the discharge hole 2 provided in the housing 5.
7 to the suction side of the pump. The groove 24 on one side of the supply groove 23 has a radial passage 28,
Annular groove 29 and supply/discharge hole 3 provided in housing 5
0 to one chamber of a power cylinder (not shown), and the groove 25 on the other side is also connected to the radial passage 3.
1. It communicates with the other chamber of the power cylinder through the annular groove 32 and the supply/discharge hole 33, but in the neutral state, the respective flow path areas of the supply groove 24 and the grooves 24 and 25 on both sides thereof are substantially equally, both grooves 2
Since there is no pressure difference between the cylinders 4 and 25, the power cylinder remains inactive.

On the other hand, when the input shaft 1 is rotated in one direction, both protrusions 10,
Therefore, relative rotation occurs between the valve rotor 13 and the valve sleeve 14, and a difference occurs in the flow path area between the supply groove 23 and the grooves 24 and 25 on both sides thereof depending on the direction of rotation. Along with this, both grooves 24, 2
A pressure difference occurs between the two. As a result, both grooves 24, 2
Power cylinders communicating with each of the steering wheels 5 are actuated to provide an auxiliary force in the steering direction, as is well known in the art.

As described above, the present invention provides a protrusion that is integrated with the valve rotor within the valve sleeve, has the tip of the protrusion protrude to the outside through a through hole drilled in the valve sleeve, and also provides a connection between the protrusion and the through hole. A predetermined gap is formed between the valve sleeve in the rotating direction of the valve sleeve, and a protrusion is provided that is integral with the valve sleeve, and both protrusions are held in a predetermined position by the elastic force of a spring disposed on the outer periphery of the valve sleeve. Since the valve sleeve is designed to be held in place, it is possible to provide both of the protrusions at positions close to each other in the axial direction, which is preferable for strength, and at the abutting portion of the input shaft and output shaft. , it is possible to obtain a sufficient amount of repulsive force even if the configuration of that part is made smaller than in the past.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, FIG. 2 is an exploded perspective view of the main parts of FIG. 1, and FIGS.
The figures are sectional views taken along lines - and - in FIG. 1, respectively. 1...Input shaft, 2...Output shaft, 10, 11...
Projection, 12... C-shaped spring, 13... Valve rotor, 1
4...Valve sleeve, 16...Through hole.

Claims (1)

[Claims] 1. An input shaft linked to the steering wheel, an output shaft disposed on the same axis as the input shaft and linked to the steering wheel, and an input shaft provided on either the input shaft or the output shaft. and a valve sleeve provided on the other shaft and rotatably fitted around the outer periphery of the valve rotor, the valve rotor and the valve sleeve are configured to respond to relative rotational displacement between the input shaft and the output shaft. In a power steering device that constitutes a control valve that controls the supply and discharge of pressure fluid to and from a power cylinder, a protrusion integral with the valve rotor is provided in the valve sleeve,
The tip of this protrusion protrudes to the outside through a through hole formed in the valve sleeve, and a predetermined gap is formed between the protrusion and the through hole in the rotational direction of the valve sleeve. A power steering device characterized in that a protrusion that rotates together with the valve sleeve is provided, and both protrusions are held in a predetermined position by the elastic force of a spring disposed on the outer periphery of the valve sleeve.