JPS63544Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention includes 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 A spool in a control valve of a power steering device, comprising a spool valve displaceable in the axial direction on one outer periphery of the spool valve, the spool valve being displaceable in the axial direction in conjunction with the conversion mechanism to switch the pressure oil supply flow path. This invention relates to a valve displacement conversion mechanism.

In conventional control valves of this type, for example, a ball, which is a component of the conversion mechanism, is rotatably held by a ball retainer ring, and is held in a spiral groove having a V-shaped cross section provided on either of the shafts. engaged. By the way, in this type of control valve,
Because the distance from the center of the ball to the point contact point A between the ball and the ball retainer ring is greater than the distance from the center of the ball to the point contact point B between the ball and both walls of the spiral groove, if the ball slips, the ball retainer ring A large sliding frictional force is generated at the point contact area A with both walls, and a displacement regulating force of the spool valve, which is larger than this frictional force, acts on the point contact area B with both wall surfaces. As a result, the following various problems occur. That is, (1) the displacement of the spool valve is restricted, impairing the smooth operation of the control valve, and causing wear on both walls of the spiral groove, the ball, etc.

(2) Due to wear on both walls, balls, etc., play occurs between the spiral groove, ball, and ball retainer ring, making it impossible to hold the spool valve at the set neutral position, resulting in a major change in the operating characteristics of the control valve. This may cause damage to the control valve function.

The present invention attempts to deal with such problems, and the present invention will be explained below based on the drawings. Fig. 1 shows a control valve employing a spool valve displacement conversion mechanism according to an example of the present invention. It is shown. This control valve 10 is used in a rack and pinion type power steering device, and a valve housing 11 of the control valve 10 is connected to a gear box 10.
The input shaft 20 and the output shaft 30 are fluid-tightly inserted into the valve housing 11, and the needle bearing 12 and the ball bearing 13 are fluid-tightly fixed to the gear housing 110 of the valve housing 11.
It is coaxially supported via. Furthermore, a cylindrical spool valve 40 and a valve case 50 are arranged concentrically with the input shaft 20 within the valve housing 11 .

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. In addition, a first
As shown in FIGS. 3 to 3, a pair of spiral grooves 24, 24 having a V-shaped cross section and a pair of notches 25, 25 are provided.

The output shaft 30 has at its upper end a pair of protruding pieces 31, 31 that protrude into each notch 25 of the input shaft 20, and a guide pin 32 is fixed to each of these protruding pieces 31 in the radial direction. . Each guide pin 32
are respectively fitted into a pair of axial guide grooves 41, 41 provided opposite to each other at the lower end of the spool valve 40, and guide the movement of the spool valve 40 in the axial direction. In addition, each protruding piece 3 of the output shaft 30
1 are arranged in each notch 25 of the input shaft 20 with a predetermined gap in the circumferential direction, thereby allowing the input shaft 20 and the output shaft 30 to rotate relative to each other. Note that a pinion 3 is provided at the lower end of the output shaft 30.
3 is provided, and this pinion 33 faces into the gear housing 110 and
It meshes with the rack of the steering rack 120 assembled inside.

The spool valve 40 has a pair of through holes 4 at its lower end as shown in FIGS. 1, 2, and 4.
2 and 42 are provided and are fitted into the valve case 50 so as to be movable in the axial direction. Further, an upper annular groove 43 is provided on the outer peripheral surface of the spool valve 40.
a, a central annular groove 44a and a lower annular groove 45a are provided. Note that both upper and lower annular grooves 43a, 4
5a communicates with the inside of the spool valve 40 via through holes 43b and 45b.

The valve case 50 has a central annular groove 51a constantly communicating with the inflow port 11A of the valve housing 11 on its outer peripheral surface, and a first annular groove 51a of the valve housing 11.
Upper annular groove 52a constantly communicating with port 11B
A lower annular groove 53a is provided which constantly communicates with the second port 11C of the valve housing 11. In addition, a spool valve 40 is provided on the inner circumferential surface.
An upper annular groove 52b selectively communicates with the upper and central annular grooves 43a and 44a, and a lower annular groove 53b selectively communicates with the central and lower annular grooves 43a and 45a.
a and 52b communicate through a through hole 52c, and lower annular grooves 53a and 53b communicate through a through hole 53c. This valve case 50 is connected to the output shaft 3
Support member 34 fitted to the upper end of 0 so as to be relatively rotatable
The central annular groove 51a is always in communication with the central annular groove 44a of the spool valve 40 via the through hole 51c. Moreover, when the spool valve 40 is located in the neutral state (see FIG. 1), the spool valve 40
The central annular groove 44a of the valve case 50 connects the spool valve 4 through the upper and lower annular grooves 52a and 53a of the valve case 50.
It communicates with the upper and lower annular grooves 43a and 45a of 0.
As a result, the pressure oil from the inflow port 11A passes through the inside of the spool valve 40 and the valve housing 1
It flows back into the reservoir via the drain port 11D of No.1. Note that when the spool valve 40 is displaced upward, the pressure oil from the inflow port 11A flows through the through hole 52.
c. Pressure oil is supplied to one oil chamber of the power cylinder through the first port 11B, and at the same time, pressure oil in the other oil chamber is returned to the reservoir through the second port 11C, the through hole 53c, and the drain port 11D. Also,
When the spool valve 40 is displaced downward, the pressure oil from the inflow port 11A is supplied to the other oil chamber of the power cylinder via the through hole 53c and the second port 11C, and at the same time, the pressure oil in one oil chamber is supplied to the first port. 11B, through hole 52c and drain port 11D.

Therefore, each through hole 42 of the spool valve 40
As clearly shown in FIG. 4, each helical groove 2
A circular hole 42a facing 4 and a circular hole 42a
It consists of a pair of slit holes 42b extending perpendicularly to the spiral groove 24, and each of these through holes 4
2 includes a rolling member 60 shown in FIGS. 5 and 6.
is accommodated. This rolling member 60 consists of a roller shaft 60a and a roller 60b rotatably supported on the roller shaft 60a, and is fitted into each through hole 42 in the state shown in FIG. It is fixed by a ring 61 in the states shown in FIGS. 1, 2, and 8. The retainer ring 61 has a circular hole 61a that faces the circular hole 42a of each through hole 42 of the spool valve 40 and has a slightly smaller diameter than the circular hole 42a, and has a pair of circlips fitted in each annular mounting groove of the spool valve 40. It is attached by 62,62. As a result, the roller shaft 60a of the rolling member 60
is supported and fixed in the through hole 42 of the spool valve 40, and the roller 60b is connected to the spiral groove 24 of the input shaft 20 and the circular hole 61a of the retainer ring 61.
It faces inside and is held so that it can roll.

In the control valve 10 configured in this manner, when the steering wheel (not shown) is operated, the input shaft 20 rotates relative to the output shaft 30 while twisting the torsion bar 21, and the roller 60b of the rolling member 60 is rotated. It rolls within the spiral groove 24 to displace the spool valve 40 upwardly or downwardly from its neutral position. Therefore, 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) through the first port 11B or the second port 11C, and at the same time, the pressure oil in the left or right oil chamber is supplied to the second port 11B or the second port 11C. 11C
Alternatively, it is returned to a reservoir (not shown) via the first port 11B and the drain port 11D. As a result, the steering operation force of the steering wheel is significantly reduced. In the steering operation of the steering wheel, the spool valve 40 displaced from the neutral position is returned to the neutral position by the relative rotation of the output shaft 30 with respect to the input shaft 20 via the steering rack 120.

By the way, in the control valve 10, the rolling member 60 is constituted by a roller shaft 60a and a roller 60b rotatably supported on the roller shaft 60a, and the retainer ring 61 restricts the rolling of the roller 60b. It is fixed in the through hole 42 of the spool valve 40. Therefore, the roller 60b is not affected by the retainer ring 61 at all and rolls much more smoothly than in the conventional ball system. As a result, the displacement conversion efficiency of the spool valve 40 is improved, the operability of the control valve 10 is improved, and wear on both wall surfaces of the spiral groove 24 is suppressed. Also, since wear on both walls is suppressed,
There is no friction in the steering operation of the steering wheel, which improves the operational feeling, and the spiral groove 2
4 and the roller 60b is suppressed.
Furthermore, since the occurrence of backlash is suppressed, the spool valve 40 can be held at the set neutral position, and the hysteresis of the hydraulic characteristics with respect to the torque of the input shaft 20 does not increase, and the steering wheel returns well. It also has various effects in terms of operating characteristics compared to the conventional ball system, such as there being no difference in hydraulic characteristics during left and right steering operations and no discomfort to the driver.

FIG. 9 shows a modification of the retainer ring 61. This retainer ring 61 is similar to the circular hole 6 of the retainer ring 61 in the first embodiment.
1a, an annular recess 61 is provided approximately at the center of the inner wall.
b. This annular recess 61b
The retainer ring 61 partially accommodates the outer peripheral portion of the roller 60b, and due to the presence of the annular recess 61b, the roller shaft 60a is supported without restricting the rolling of the roller 60b.

Further, FIG. 10 shows a modification of the spool valve 40. This spool valve 40
is the housing part 4 for the valve body 40a and the rolling member 60.
0b. The accommodating part 40b is
As shown in FIGS. 10 to 12, the outer periphery of the cylindrical portion is provided with a pair of through holes 42, 42 for accommodating the rolling member 60, and the inner periphery of the cylindrical portion is a shaft into which each guide pin 32 of the output shaft 30 is fitted. A pair of guide grooves 41, 4 in the direction
1, and a pair of locking pieces 46, 4 at the tip of the cylindrical portion.
It is equipped with 6. The accommodating portion 40b is removably attached to the lower end of the valve body 40a by engaging each of the locking pieces 46 in an annular recess 47 provided at the lower end of the valve body 40a. In addition, the housing section 4
A rolling member 60 is accommodated in each through hole 42 of 0b, as in the first embodiment, and is supported and fixed by a retainer plate 63. The retainer plate 63 is provided with a square hole 63a into which a part of the outer periphery of the roller 60b of the rolling member 60 is loosely fitted.
roller shaft 60 without restricting the rolling of b.
I support a. Note that the control valve using the spool valve 40 is the control valve 1 shown in the first embodiment.
0 and has similar effects.

Further, FIG. 13 shows another modification of the spool valve 40. This spool valve 4
0 is constituted by a valve body 40a and a housing portion 40c for the rolling member 60. Accommodation part 40c
As shown in FIGS. 13 to 15, a pair of protrusions 4 are formed by cutting out a part of the outer periphery of the cylindrical portion.
8 and 48, and a through hole 42 for accommodating a rolling member 60 is formed in each protrusion 48. Further, each guide pin 32 of the output shaft 30 is provided on the inner periphery of the cylindrical portion.
A pair of guide grooves 41, 41 in the axial direction into which the cylindrical portion is fitted are formed, and a pair of locking pieces 4 are provided at the tip of the cylindrical portion.
6,46 are formed. This housing section 40c
is removably attached to the lower end of the valve body 40a by engaging each locking piece 46 in an annular recess 47 provided at the lower end of the valve body 40a. Further, each through hole 42 of the housing portion 40c is formed in a cylindrical shape, and the roller 60b of the rolling member 60 is inserted into the through hole 42 and one end thereof is fitted into the spiral groove 24. The roller shaft 60a is attached to the protrusion 4
By press-fitting from the side of 8, it is held in the through hole 42 so that it can roll. Note that a control valve using the spool valve 40 also operates in the same manner as the control valve 10 shown in the first embodiment, and has the same effects.

In addition, in the present invention, a first shaft and a second shaft coaxially supported within the housing, a conversion mechanism that converts rotational displacement between these two shafts into axial displacement, and an outer periphery of one of the two shafts are provided. The present invention is applied to various control valves of power steering devices including a spool valve that is disposed to be displaceable in the axial direction and is displaceable in the axial direction in conjunction with the conversion mechanism to switch the pressure oil supply flow path. It is something.

As explained above, the present invention provides various control valves for the power steering mechanism, in which the transmission mechanism
A spiral groove provided on the outer periphery of one of the two shafts, and a roller rotatably supported on a roller shaft assembled to the spool valve and rotatably engaged with the spiral groove. Particularly noteworthy are its structural features. Therefore, according to the present invention, the roller can be rolled extremely smoothly in the spiral groove without being affected by the holding means, thereby improving the displacement conversion efficiency of the spool valve and controlling the control valve. The operability of the control valve is improved, and abrasion of both wall surfaces of the spiral groove is suppressed, so that the operation characteristics of the control valve are maintained favorably. As a result, a smooth steering feeling can be obtained in the vehicle.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view taken along the - line in Fig. 2 showing an example of a control valve embodying the present invention;
Figure 3 is a side view showing the lower end of the input shaft, Figure 4 is a side view showing the lower end of the spool valve, Figure 5 is a front view of the rolling member, and Figure 5 is a side view showing the lower end of the input shaft. 6 is a side view thereof, FIG. 7 is a side view showing the lower end of the spool valve housing the rolling member, FIG. 8 is a side view showing the lower end of the spool valve with the rolling member supported, and FIG. FIG. 9 is a longitudinal sectional view showing a modified example of the retainer ring, FIG. 10 is a side view of the lower end showing a modified example of the spool valve, and FIG.
FIG. 1 is a side view of the housing part constituting the spool valve, FIG. 12 is a perspective view thereof, FIG. 13 is a side view of the lower end showing another modification of the spool valve, and FIG.
The drawings are a cross-sectional view taken along the line - in FIG. 13, and FIG. 15 is a perspective view of the accommodating portion constituting the spool valve. Explanation of symbols, 10... Control valve, 20... Input shaft, 21... Torsion bar, 24... Spiral groove,
30...Output shaft, 40...Spool valve, 50
...Valve case, 60...Rolling member, 60a...
...Roller shaft, 60b...Roller, 61...
Retainer ring, 63...retainer plate.

Claims (1)

[Scope of utility model registration request] A first shaft and a second shaft coaxially supported within the housing, a conversion mechanism that converts the rotational displacement between these two shafts into axial displacement, and one of the two shafts that can be displaced in the axial direction on the outer periphery thereof. In the control valve of the power steering device, the control valve includes a spool valve that is disposed and is displaceable in the axial direction to switch the supply flow path of pressure oil in conjunction with the conversion mechanism, and the transmission mechanism is connected to one of the two shafts. A spool comprising a spiral groove provided on the outer periphery and a roller rotatably supported on a roller shaft assembled to the spool valve and rotatably engaged with the spiral groove. Valve displacement conversion mechanism.