JPS6232939Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an air venting mechanism in a control valve of a power steering device.

Generally, this type of control valve has an input shaft and an output shaft arranged coaxially and relative to each other in a housing having a first port and a second port connected to a supply port and a discharge port for hydraulic oil and both oil chambers of an actuator, respectively. The input shaft is rotatably supported, and on the outer periphery of the input shaft, the first
A spool valve having a central annular groove that can communicate with the port and the second port, and both upper and lower annular grooves that are always in communication with the discharge port and can communicate with the first port and the second port, respectively, concentrically and axially. The spool valve is disposed movably, and relative rotation of the two shafts displaces the spool valve in the axial direction via a displacement converting means provided between the spool valve and both shafts, thereby switching the hydraulic oil supply flow path. It is composed of

By the way, in this type of control valve, the discharge port is provided at the bottom of the housing for reasons such as layout, and when supplying hydraulic oil during vehicle assembly or repair, etc., the discharge port is formed at the top of the spool valve inside the housing. Since the flow of hydraulic oil to the oil chamber is poor, air remains in the oil chamber. While the control valve is in use, this stagnant air is discharged into the atmosphere little by little along with the hydraulic oil that is returned to the reservoir of the oil pump, but the discharge is not always sufficient. As a result, air inevitably accumulates in the upper oil chamber of the control valve, which has a subtle effect on the operation of the power steering system.Furthermore, the oil level gradually decreases, causing the timing of replenishing the hydraulic oil to be lost. Especially at extremely low temperatures, the oil level may drop below the lower limit, causing problems with the oil pump's characteristics.

The present invention was devised to address these problems, and the present invention will be explained below based on the drawings. FIG. 1 shows an example of a control valve implementing the present invention. 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 fluid-tightly fixed to a gear housing 110 of a gearbox 100. , an input shaft 20 and an output shaft 30 are inserted fluid-tightly and coaxially supported via a needle bearing 12 and a ball bearing 13.
In addition, an input shaft 20 is provided inside the valve housing 11.
A cylindrical spool valve 40 and a valve case 50 are arranged concentrically.

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 connects its upper end to the input shaft 22 with a pin 22.
It is assembled by connecting the upper end to the output shaft 30 and the lower end thereof to the upper end of the output shaft 30 using the pin 23. Further, as shown in FIGS. 1 and 2, a pair of spiral grooves 24 are provided on the lower outer periphery of the input shaft 20.
24 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 42, 42 provided at its lower end, and is fitted into the valve case 50 so as to be movable in the axial direction. A ball 27 that is rotatably held by a ball retainer ring 26 attached to the lower end of the spool valve 40 is fitted into each of these through holes 42 , and a part of the outer periphery of this ball 27 is formed into a spiral groove 24 . is engaged in. Note that a spring 28 that is engaged with the outer periphery of the input shaft 20 is seated in an annular recess provided inside the upper end of the spool valve 40, and by urging the spool valve 40 downward with this spring 28, This is intended to prevent backlash between the spiral groove 24 and the ball 27 and vibration of the spool valve 40. Further, an upper annular groove 43a, a central annular groove 44a, and a lower annular groove 45a are provided on the outer peripheral surface of the spool valve 40, and the lower annular groove 45a communicates with the inside of the spool valve 40 through a through hole 45b. ing.

The valve case 50 has a central annular groove 51a constantly communicating with the supply port 11A of the valve housing 11 on its outer peripheral surface, and an upper annular groove 52a always communicating with the first port 11B of the valve housing 11.
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 that can communicate with the upper and central annular grooves 43a and 44a, and a lower annular groove 53b that can communicate with the central and lower annular grooves 44a and 45a are provided. The lower annular groove 53 communicates through the hole 52c.
a and 53b communicate through a through hole 53c.
As shown in FIGS. 1 and 3, the valve case 50 is fixed in a predetermined position by engagement with a support member 34 that is relatively rotatably fitted to the upper end of the output shaft 30. The groove 51a is the through hole 51
c through the central annular groove 44 of the spool valve 40
It is always in communication with a. Also, spool valve 4
0 is in the neutral state (see FIG. 1), the central annular groove 44a of the spool valve 40 connects to the upper and lower annular grooves 43a and 43a of the spool valve 40 via the upper and lower annular grooves 52a and 53a of the valve case 50, respectively.
45a.

As shown in FIGS. 4 to 6, a pair of notches 4 are provided on the outer periphery of the upper end of the spool valve 40.
3b and 43b are provided. Each of these notches 43b extends in the axial direction from the upper end of the spool valve 40 and reaches its upper annular groove 43a, and as shown in FIG. It communicates with the formed upper oil chamber R. This results in
When the spool valve 40 is in the neutral state, part of the hydraulic oil supplied from the oil pump through the supply port 11A is transferred to the central annular groove 44a of the spool valve 40, the upper annular groove 52b of the valve case 50, and the spool valve. 40 upper annular groove 43a
and flows into the upper oil chamber R through each notch 43b, into the spool valve 40 and the discharge port 11.
It is returned to the oil pump reservoir via D.
The remainder of the hydraulic oil is stored in the central annular groove 44a of the spool valve and the lower annular groove 53 of the valve case 50.
b, it flows into the spool valve 40 through the lower annular groove 45a and the through hole 45b of the spool valve 40, and is returned to the reservoir via the discharge port 11D. On the other hand, when the spool valve 40 is displaced upward, the hydraulic oil supplied from the supply port 11A is transferred to the central annular groove 44a of the spool valve 40, the through hole 52c of the valve case 50, and the first port 11B.
is supplied to one oil chamber of the power cylinder through
At the same time, the hydraulic oil in the other oil chamber of the power cylinder is transferred to the second port 11c and the through hole 53 of the valve case 50.
c, it is returned to the reservoir via the through hole 45b of the spool valve 40 and the discharge port 11D. Furthermore, when the spool valve 40 is displaced downward, the hydraulic oil supplied from the supply port 11A is transferred to the central annular groove 44a of the spool valve 40 and the valve case 5.
At the same time, the hydraulic oil in one oil chamber of the power cylinder is supplied to the first port 11B and the upper annular groove 43a of the spool valve 40 through the second port 11c and the second port 11c.
The oil flows into the upper oil chamber R through each notch 43b, and is further returned to the reservoir through the spool valve 40 and the discharge port 11D.

In the control valve 10 configured in this way, when the steering wheel (not shown) is operated, the input shaft 20 twists the torsion bar 21 and rotates relative to the output shaft 30, causing the ball 2 to rotate.
7 in the spiral groove 24 to displace the spool valve 40 upward or downward from its neutral position. Therefore, the hydraulic oil supplied from the supply port 11A is transferred to the first port 11B or the second port 1.
1c to the right or left oil chamber (not shown) of the power cylinder, and at the same time, the hydraulic oil in the left or right oil chamber is returned to a reservoir (not shown) through the second port 11c or the first port 11B, and the discharge port 11D. As a result, the steering operation force of the steering wheel is significantly reduced. It should be noted that when the steering operation of the steering wheel is stopped, the spool valve 40 displaced from the neutral position is moved to the output shaft 30 via the steering rack 120.
It returns to the neutral position by relative rotation with respect to the input shaft 20.

By the way, in the control valve 10, the hydraulic oil that is recirculated through the upper annular groove 43a of the spool valve 40 and the discharge port 11D is discharged from the discharge port 11D through the spool valve 40 and the upper oil chamber R of the valve case 50. It is configured. For this reason, while the hydraulic oil flows through the upper oil chamber R, it forms a vortex and disperses the air staying in the upper oil chamber R minutely, and these minute air particles are discharged from the discharge port 11D together with the hydraulic oil and are discharged into the reservoir. released into the atmosphere. As a result, the air remaining in the upper oil chamber R is quickly discharged, and the oil level of the hydraulic oil in the reservoir can be quickly corrected to the normal level, allowing steering control without impairing the oil pump function. The operating characteristics of the mechanism are maintained well. In addition, the lubrication of the oil seal section, bearings, etc. in the upper part of the valve housing 11 is improved, and there is no rust on the inner upper part of the valve housing 11 even when the valve housing 11 is not used for a long period of time, and the power steering control caused by the occurrence of rust is prevented. Mechanism malfunctions, etc. are resolved.

Note that the present invention is applicable not only to the control valve of the type shown in the above embodiment, but also to control valves that do not employ the valve case 50, as well as to both oil chambers of the hydraulic oil supply port and discharge port and the actuator. An input shaft and an output shaft are coaxially and rotatably supported in a housing provided with a first port and a second port respectively connected to the housing, and an input shaft and an output shaft are provided on the outer periphery of the input shaft in constant communication with the supply port. and a spool valve having a central annular groove that can communicate with the first port and the second port, and upper and lower annular grooves that are always in communication with the discharge port and can communicate with the first port and the second port, respectively. the spool valve is arranged so as to be movable in the axial direction and in the axial direction, and the spool valve is displaced in the axial direction by the relative rotation of the two shafts via a displacement converting means provided between the spool valve and the two shafts, thereby supplying hydraulic oil. It is applied to various types of control valves in power steering devices that switch flow paths.

In summary, in the present invention, in the various types of control valves described above, a notch communicating with the upper annular groove is provided in the axial direction on the outer periphery of the upper end of the spool valve, and the upper annular groove and the upper oil chamber of the housing are connected. The structure is characterized in that the hydraulic oil discharged through the upper annular groove and the discharge port is discharged from the discharge port through the upper oil chamber of the housing. The air remaining in the upper part of the housing can be quickly discharged using hydraulic oil, and the adverse effect on the operating characteristics of the steering mechanism caused by the air remaining can be eliminated.

[Brief explanation of the drawing]

FIG. 1 is a second diagram showing an example of a control valve according to the present invention.
Figure 2 is a longitudinal cross-sectional view taken along line - in Figure 1, Figure 3 is a cross-sectional view taken along line - in Figure 1, and Figure 3 is a cross-sectional view taken along line - in Figure 1.
4 is a front view of the spool valve, FIG. 5 is a partial longitudinal sectional side view thereof, and FIG. 6 is a plan view thereof. Explanation of symbols, 10... Control valve, 11... Valve housing, 20... Input shaft, 30... Output shaft,
40... Spool valve, 43a... Upper annular groove, 43b... Notch, 50... Valve case.

Claims (1)

[Scope of utility model registration request] An input shaft and an output shaft are coaxially and relatively rotatably supported in a housing having a first port and a second port respectively connected to a hydraulic oil supply port and a discharge port and both oil chambers of an actuator,
On the other hand, the outer periphery of the input shaft includes a central annular groove that is always in communication with the supply port and can be communicated with the first and second ports, and a central annular groove that is always in communication with the discharge port and can be connected with the first and second ports. Spool valves with upper and lower annular grooves that can communicate with each other are arranged concentrically and movably in the axial direction,
The power steering device is configured to displace the spool valve in the axial direction through a displacement converting means provided between the spool valve and both shafts by relative rotation of the two shafts, thereby switching a hydraulic oil supply flow path. In the control valve, a notch communicating with the upper annular groove is provided in the outer periphery of the upper end of the spool valve in the axial direction to communicate the upper annular groove with the upper oil chamber of the housing, and the upper annular groove and the discharge port are provided in the control valve. The air vent mechanism is characterized in that hydraulic oil discharged through the housing is discharged from the discharge port through an upper oil chamber of the housing.