JPS6364348B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spool valve displacement conversion mechanism in a control valve of a power steering device, and more specifically, to a spool valve displacement conversion mechanism in a control valve of a power steering device, and more particularly to a first shaft and a second shaft coaxially supported in a housing, and In a control valve of a power steering device, which is equipped with a conversion mechanism that converts rotational displacement between shafts into axial displacement, and a spool valve that is displaced in the axial direction and switches the pressure oil supply flow path in cooperation with the conversion mechanism. This invention relates to a spool valve displacement conversion mechanism.

In conventional control valves of this kind, the displacement conversion mechanism includes, for example, a spiral groove with a V-shaped cross section provided on the outer periphery of one of the two shafts (the input shaft or the output shaft), and a fitting hole provided in the spool valve. The spool valve is comprised of a ball that is rotatably held by the spool valve and engages with the spiral groove, and a guide pin that is provided on the other of the two shafts (output shaft or input shaft) and engages with the guide groove of the spool valve. Therefore, the operating characteristics of the control valve largely depend on the inclination angle of the spiral groove. Therefore, the control valve is dedicated to the same vehicle model, and lacks versatility to different vehicle models. Furthermore, in general, in this type of control valve, the conversion mechanism inevitably deteriorates in its operating characteristics due to wear that occurs during use, so maintenance and inspection of the conversion mechanism is required, and the conversion mechanism must be replaced if necessary. However, the conversion mechanism of the control valve is mainly composed of the input shaft, output shaft, spool valve, etc., which are the main components of the control valve, and when replacing the conversion mechanism, the main components of the control valve must be replaced. There are disadvantages in that the members must be replaced, and furthermore, there are disadvantages in that extremely complicated assembly work is involved in assembling the main components at the time of replacement.

The present invention was made to address these problems, and its main purpose is to provide a highly versatile control valve that can be used in many types of vehicles, and to replace the main components of the control valve. To provide a control valve of this type that allows a conversion mechanism to be replaced without any trouble and does not require complicated assembly work when replacing the mechanism.

Hereinafter, the present invention will be explained based on the drawings. FIGS. 1 and 2 show an example of a control valve embodying the present invention. This control valve 10 is used in a rack and pinion type power steering device, and the valve housing 11 of the control valve 10 is
is fluid-tightly fixed to a gear housing 110 of a gearbox 100, and an input shaft 20 and an output shaft 30 are fluid-tightly inserted into this valve housing 11 and are connected via a needle bearing 12 and a ball bearing 13. Coaxially supported. Further, a cylindrical spool valve 40 is arranged within the valve housing 11 concentrically with the input shaft 20.

The input shaft 20 is pivotally supported at its lower end by the upper end of the output shaft 30 via a needle bearing 14, and is connected to the output shaft 30 by a torsion bar 21 inserted through its axis. This torsion bar 21 has its upper end connected to the input shaft 2 by a pin 22.
0 and its lower end is connected to the upper end of the output shaft 30 by means of a pin 23. Further, a pair of notches 24, 24 are provided on the lower outer periphery of the input shaft 20.

The output shaft 30 is provided with a pair of protruding pieces 31, 31 at its upper end that protrude into the respective notches 24 of the input shaft 20. Each protruding piece 31 is arranged within each notch 24 of the input shaft 20 with a predetermined gap in the circumferential direction, so that the input shaft 20 and the output shaft 30 can rotate relative to each other. Note that a pinion 33 is provided at the lower end of the output shaft 30, and this pinion 3
3 faces into the gear housing 110 and meshes with the rack of a steering rack 120 assembled therein.

The spool valve 40 has an upper annular groove 41a, a central annular groove 42a, and a lower annular groove 4 on its outer peripheral surface.
3a is provided, and both upper and lower annular grooves 41a, 4
3a communicates with the inside of the spool valve 40 via through holes 41b and 43b. The spool valve 40 is slidably and rotatably fitted into the valve housing 11, and has a central annular groove 4.
2a is in constant communication with an inflow port 11a provided in the valve housing 11. This inflow port 11
a indicates the center annular groove 42a and the upper annular groove 11e provided in the valve housing 11 when the spool valve 40 is in the neutral state (see FIG. 1).
It communicates with the upper annular groove 41a via the central annular groove 42a and the lower annular groove 11f provided in the valve housing 11 with the lower annular groove 43a. As a result, the pressure oil flowing in from the inflow port 11a passes through the inside of the spool valve 40 and drain port 11b of the valve housing 11.
It is recycled to a reservoir (not shown) through the . on the other hand,
When the spool valve 40 is displaced upward due to cooperation with a conversion mechanism 50 to be described later, the spool valve 4
The communication between the central annular groove 42a of the spool valve 40, the lower annular groove 11f of the valve housing 11, and the upper annular groove 41a of the spool valve 40 and the upper annular groove 11e of the valve housing 11 is cut off. As a result, the pressure oil flowing in from the inflow port 11a is transferred to the upper annular groove 11e of the valve housing 11 and the first port 11c of the valve housing 11 communicating with the upper annular groove 11e.
is supplied to one oil chamber of the power cylinder (not shown) through the valve housing 11, and at the same time, the pressure oil of the other power cylinder is supplied to the second port 11d of the valve housing 11.
It passes through the lower annular groove 11f communicating with this, the lower annular groove 43a of the spool valve 40, and the through hole 43b, passes through the inside of the spool valve 40, and is further returned to the reservoir via the drain port 11b. Note that when the spool valve 40 is displaced downward, the pressure oil flowing from the inflow port 11a is supplied to the other oil chamber of the power cylinder via the second port 11d, and at the same time, the pressure oil of one hydraulic pressure of the power cylinder is supplied to the first oil chamber. Port 11c and drain port 11b
It is then returned to the reservoir.

Therefore, the conversion mechanism 50 of the control valve 10 is
A pair of first fixing pins 51, 51, which are cam followers, protrude in the radial direction from the upper end of the output shaft 30, and a pair of second fixing pins 52, which are cam followers, protrude in the radial direction from the lower end of the input shaft 20. , 52, an operating sleeve 53 fixed to the lower end of the spool valve 40, and a pair of cam members 54 attached to the operating sleeve 53.

As shown in FIGS. 3 to 5, the actuating sleeve 53 consists of a cylindrical sleeve main body 53a and a pair of arcuate connecting parts 53b, 53b protruding from both sides of the upper end of the sleeve main body 53a. A pair of cam grooves 53c, 53c extending in the axial direction are formed in the inner wall of the portion 53a, and a pair of fitting holes 53d, 53c are formed in the peripheral wall of the sleeve main portion 53a.
53d is formed. Each of these fitting holes 53d
Serrations are engraved on the inner circumference. Moreover, an arcuate recess 53e is formed in each connecting portion 53b. This actuating sleeve 53 is the sixth
A snap spring 61 shown in the figure is connected to the lower end of the spool valve 40 by fitting into the arcuate recess 53e of each connecting portion 53b and an annular recess 44 provided at the lower end of the spool valve 40. In this state, the tips of the first fixing pins 51 implanted in the upper end of the output shaft 30 face and engage with the cam grooves 53c of the sleeve main body 53a.

As shown in FIGS. 7 and 8, the cam member 54 has a cylindrical shape with serrations carved around the entire circumference, and a cam groove 54a is formed on its inner surface, and a cam groove 54a is formed on its inner surface. An annular recess 54b is formed therein. The cam member 54 fits into each fitting hole 5 of the actuating sleeve 53 with its cam groove 54a inclined at a predetermined angle with respect to the axial direction of the actuating sleeve 53.
3d, and the annular recess 5
A snap spring 62 fitted to the actuating sleeve 53 positions the actuating sleeve 53 inwardly and prevents it from coming off, and a snap spring 63 fitted to an annular recess 53f provided on the outer periphery of the actuating sleeve 53 prevents it from coming off outward. There is. In this state, the tips of the second fixing pins 52 implanted at the lower end of the input shaft 20 face and engage with the cam grooves 54a (slanted cam grooves) of the cam member 54.

In the control valve 10 configured in this way,
When a steering wheel (not shown) is operated, the input shaft 20 rotates relative to the output shaft 30 while twisting the torsion bar 21, and at the same time, the second fixing pin 52 rotates together with the input shaft 20. Therefore, by the action of the first fixing pin 51 and the second fixing pin 52, the actuating sleeve 53 and the spool valve 40 are moved up and down and displaced. As a result, the pressure oil flowing in from the inflow port 11a is supplied to the right or left oil chamber of the power cylinder (not shown) via the first port 11c or the second port 11d, and at the same time, the pressure oil in the left or right oil chamber is supplied to the second or right oil chamber. The water is returned to a reservoir (not shown) through the port 11d or the first port 11c, and the drain port 11b. Therefore, the steering operation force of the steering wheel is significantly reduced. Further, when the steering operation of the steering wheel is stopped, the output shaft 30 rotates relative to the input shaft 20 via the steering rack 120, and at the same time, the first fixing pin 51
Rotates together with 0. For this reason, the first fixing pin 5
Due to the action of the first and second fixing pins 52, the operating sleeve 53 and the spool valve 40 return to the neutral position while rotating. As a result, the inflow port 11
The supply of pressure oil from a to the power cylinder is stopped, and the pressure oil is returned to the reservoir via the drain port 11b.

By the way, in the control valve 10, since the cam member 54 forming the inclined cam groove 54a is attached to the actuation sleeve 53 by serration fitting, when the cam member 54 is attached, the inclined cam groove 54a in the axial direction is attached. The inclination angle of the control valve can be easily changed, thereby making it possible to adjust the operating characteristics of the control valve to those suitable for various vehicle types. Furthermore, when the conversion mechanism 50 of the control valve 10 becomes worn, the actuation sleeve 53 can be replaced, eliminating the need to replace the main components of the control valve as in the past, and requiring no complicated assembly when replacing the control valve. Work can also be eliminated.

In addition, in this embodiment, the spool valve 4
0 is arranged concentrically with the input shaft 20 and the actuation sleeve 53 is connected to the lower end of this spool valve 40. and the actuating sleeve 53 to this spool valve 40.
may be connected by appropriate means,
Further, the first fixing pin 51 may be provided on the input shaft 20 and the second fixing pin 52 may be provided on the output shaft 30, and each of these fixing pins 51 and 52 may be engaged with each of the cam grooves 53c and 54c, respectively. The cam follower may be changed to an appropriately shaped cam follower. In the present invention, the actuation sleeve 53 may be formed integrally with the spool valve 40, and it goes without saying that a highly versatile control valve can also be provided in this modification.

In summary, in the present invention, a first shaft and a second shaft coaxially supported within a housing, a conversion mechanism that converts rotational displacement between these two shafts into axial displacement, and a linkage with this conversion mechanism are provided. In the control valve of a power steering device, the conversion mechanism is provided with a spool valve that is axially displaced to switch a pressure oil supply flow path, and the conversion mechanism is a first cam follower that protrudes radially from one of the two shafts. an actuation sleeve disposed on the spool valve, the actuation sleeve having an axial cam groove that engages with the spool valve; and an inclined cam groove that engages with a second cam follower that protrudes in the radial direction on the other of the two shafts. Its feature lies in that it is constructed by a cam member that is fitted and fixed to the actuating sleeve so that the inclination angle of the cam groove with respect to the axial direction can be adjusted. Therefore, according to the present invention, the operating characteristics of the control valve can be adjusted to increase its versatility, and furthermore, the conversion mechanism can be easily replaced without replacing the main components of the control valve.

[Brief explanation of drawings]

FIG. 1 is a second diagram showing an example of a control valve according to the present invention.
Figure 2 is a cross-sectional view taken along line - in Figure 1, Figure 3 is a front view of the actuating sleeve, Figure 4 is a side view, and Figure 5 is a plane view. 6 is a perspective view of a snap spring connecting the spool valve and the actuating sleeve, FIG. 7 is an inner side view of the cam member, and FIG. 8 is a plan view thereof. Explanation of symbols, 10... Control valve, 20... Input shaft, 30... Output shaft, 40... Spool valve,
50... Conversion mechanism, 51, 52... Fixed pin (cam follower), 53... Operating sleeve, 53c...
...Cam groove, 54...Cam member, 54a...Cam groove.

Claims (1)

[Claims] 1. A first shaft and a second shaft coaxially supported in the housing, a conversion mechanism that converts the rotational displacement between these two shafts into axial displacement, and the axial displacement due to the cooperation with this conversion mechanism. In a control valve for a power steering device equipped with a spool valve that switches a pressure oil supply flow path, the conversion mechanism is arranged in an axial direction that engages with a first cam follower that protrudes in the radial direction from one of the two shafts. an actuating sleeve provided with a cam groove and disposed on the spool valve; an inclined cam groove that engages with a second cam follower protruding in the radial direction on the other of the two shafts; A spool valve displacement conversion mechanism comprising: a cam member which is fitted and fixed so that its inclination angle with respect to the axial direction of the spool valve can be adjusted;