JPH1045009A - Control valve for hydraulic power steering device - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To provide a quiet control valve of a variable throttle portion of a rotary valve with small fluid noise. SOLUTION: Sleeve 101 and rotary spool 1
02 are formed on the circumference so as to be relatively rotatable with each other, and a supply groove 103A on the rotary spool side and a left and right control groove 104A on the sleeve side are formed with the relative rotation of the two. , 105A and the communication area between the left and right communication grooves 106A and 107A on the rotary spool side and the discharge grooves 108A and 109A on the sleeve side are controlled by the chamfered portions of the control projections 104B and 105B on the rotary spool side. The fitting portion between the left and right control grooves on the rotary spool side and the left and right communication grooves on the rotary spool side are overlapped, so that the hydraulic oil from the supply groove and the left and right communication grooves on the rotary spool side to the left and right control grooves and the discharge groove on the sleeve side The flows were all upflows.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a control valve used for a power steering device of an automobile.

[0002]

2. Description of the Related Art As a steering force control device for a power steering of this type, for example, Japanese Patent Application Laid-Open No.
No. 176 discloses this. As shown in FIGS. 3 to 5, the steering force control device for power steering disclosed in this publication inserts a pinion shaft 2 and a stub shaft 3 coaxially into a casing 1 and connects both shafts 2 and 3 to a torsion bar. 4 are linked.
A pinion 5 is formed on the pinion shaft 2, and the pinion 5 is engaged with a rack 7 formed on a rod 6 of a steering mechanism. Therefore, when the pinion shaft 2 rotates and the pinion 5 rotates, the rod 6 moves accordingly, and the wheels (not shown) are steered.

[0003] The stub shaft 3 is configured to rotate integrally with a steering wheel (not shown), and a rotary valve V is provided around the stub shaft 3.
The rotary valve V includes a rotary spool 8 integrated with the stub shaft 3 and a sleeve 9 fitted to the rotary spool 8 so as to be relatively rotatable. The sleeve 9 is connected to the pinion shaft 2 via the pin 10.
, So that both of them rotate integrally.

[0004] The rotary valve V configured as described above is switched as follows. That is, when the steering wheel is released, the stub shaft 3 rotates and the rotational force is transmitted to the pinion shaft 2 via the torsion bar 4. However, the rotation of the pinion shaft 2 is hindered by ground contact friction of the wheels and the like, so that the torsion bar 4 is twisted by that amount. Therefore, the stub shaft 3 is connected to the torsion bar 4
Is rotated more than the pinion shaft 2 by an amount corresponding to the torsion angle, and the two shafts 2 and 3 rotate relative to each other. When the shafts 2 and 3 rotate relative to each other in this manner, the rotary spool 8 and the sleeve 9 also rotate relative to each other, and the rotary valve V is switched.

As shown in FIG. 4, concave portions 11, 12, and 18 are formed on the rotary spool 8. Control projections 19 and 26 are provided between these recesses 11, 12 and 18.
Are formed on the sleeve 9, while the control grooves 28 and 35 are formed in the sleeve 9.
Is formed. And these recesses 11, 12, 1
8, each of the control projections 19 and 26 and the control grooves 28 and 35 is the first in the radial direction of the rotary valve V.
A control section I is formed, and a third control section III is formed at a position orthogonal to the first control section I.

[0006] The first control unit I has its control projections 19, 2
The edge portions 2, 23 and 26 are chamfered as shown in FIG. That is, each edge portion with a chamfered portion 40, and its length and L _1. When the rotary valve V is in the neutral position, and the distance from the edge portion of the chamfered portion 40 to the end portion of the control groove of the sleeve 9, i.e. the underlap amount as the U _1.
When the rotary valve V is switched in either direction, the first control unit I configured in this way controls the chamber 3 of the power cylinder C.
One of the valves 6 and 37 communicates with the tank passage 27, and the pressure oil of the hydraulic pump P is guided to the other.

The control projections 20, 21, and 22 of the third control unit III
Also the edge portion of the 4, 25, to form a chamfered portion 41 as shown in FIG. 5, the length of the chamfered portion 41 and L _2. When the rotary valve V is in the neutral position, and the distance from the edge portion of the chamfered portion 41 to the end portion of the control groove of the sleeve 9, i.e. the underlap amount as the U _2. The third control unit III configured as described above is connected to the pump P via a fixed throttle 42 formed on the sleeve 9. Note that these fixed apertures 42 are provided by the second control unit.
II.

In the first and third control units described above, the length L ₂ of the chamfered portion 41 is made sufficiently smaller than the length L ₁ of the chamfered portion 40 and the underlap amount U _{1 is} reduced. the amount U ₂ is sufficiently large. In addition, FIG.
It is an equivalent circuit diagram of this conventional example.

Next, the operation of the above conventional example will be described. If the steering wheel is maintained at the neutral position, the rotary valve V also maintains the neutral position shown in FIG. 4A, so that the discharge fluid of the pump P flows from the supply port 38 to the first control unit I and the tank passage 27. Returned to the tank via. Therefore, almost no pressure is generated in the power cylinder C.

If the rotary valve V is switched by turning the steering wheel from the above state, when the operating angle of the rotary valve V is small, such as when the vehicle is running at a high speed, the opening area of the third control unit III is However, the size is reduced only so as not to affect the aperture effect. Therefore, at this time, the pressure is controlled by the first control unit I and the second control unit II. And this second control unit
Since a predetermined flow rate flows out of the fixed throttle 42 constituting the II into the tank, the pressure increase of the power cylinder C can be suppressed.

Further, when the steering wheel is widened, such as when the vehicle is running at a low speed, the third control unit II
Since the opening of I suddenly decreases, the return flow decreases at a stretch. In other words, most of the supply flow rate from the pump P will be led to the first control unit I, and the pressure of the power cylinder C will rise rapidly. According to the steering force control device as described above, the pressure rise of the power cylinder C can be moderated in a range where the operating angle of the valve V is small, so that the steering can be stabilized during straight running or high speed running.

[0012]

In the conventional steering force control apparatus described above, a valve is formed as shown in FIG. 4B, which is an expanded view of the first control unit I of the rotary valve shown in FIG. 4A. When the sleeve 9 and the spool 8 rotate relative to each other as shown in the figure, the variable throttles (chamfered portions) B and D are gradually narrowed, and an assist pressure acts on the power cylinder. The direction of the oil flow in the variable throttle unit configured as described above is the so-called upflow that flows from the supply groove 11 on the rotary spool side to the left control groove 35 and the right control groove 28 on the sleeve side, and the left control on the sleeve side. It is constituted by a combination with a so-called downflow flowing from the groove 35 and the right control groove 28 to the left and right discharge grooves 18 and 12 on the rotary spool side.

For this reason, the control grooves 28, 35 on the sleeve side
When the oil flows from the flow to the discharge grooves 12 and 18 on the rotary spool side in a so-called downflow from the sleeve 9 side to the rotary spool 8 side, the oil is chamfered 40 of the control projections 19 and 26 on the rotary spool side. Since the flow flows along the chamfered portion 40 through the narrow passage sandwiched between the inner wall surfaces of the control projections 12A and 18A on the sleeve side, the flow rapidly expands at the end surface of the chamfered portion 40, and the pressure rises. ,
There is a problem that the flow tends to separate from the end surface of the chamfered portion 40 on the rotary spool side and the inner wall surfaces of the control protrusions 12A and 18A on the sleeve side and turbulent flow is easily generated, thereby increasing the generation of fluid noise. It could be confirmed by observing the flow by the visualization technique.

Therefore, an object of the present invention is to change the flow direction of the hydraulic oil in the variable throttle portion of the rotary valve from the supply groove and the left and right communication grooves on the rotary spool side to the left and right control grooves and the discharge groove on the sleeve side. An object of the present invention is to provide a quiet control valve with a small fluid noise by adopting the upflow.

[0015]

In order to solve the above-mentioned problems, the means adopted in the present invention is a stub shaft that rotates integrally with a steering wheel, an output shaft that is linked to a steering mechanism, and these two shafts. A rotary valve comprising a rotary spool and a sleeve which are switched in accordance with the relative rotation of the two shafts. A supply port for supplying hydraulic oil from a hydraulic pump is provided on the sleeve side. A left and right control groove formed on both sides of the port to supply pressure oil to the power cylinder; a cylinder control protrusion provided with a communication port disposed outside the control groove and connected to the power cylinder; A discharge groove into which the discharge oil of the power cylinder flows is formed further outside the portion, while the slot is formed on the rotary spool side. A supply groove facing the supply port of the probe side, a supply-side positioning convex portion having a chamfered portion for controlling the supply of pressurized oil to be opposed to the control groove left and right cylinder control grooves,
Left and right communication grooves opposed to the communication port, and a discharge-side control projection provided with a discharge port to the tank opposed to the discharge groove are formed, and both are fitted so as to be relatively rotatable with each other. A plurality of control units are formed on the circumference, and with the relative rotation of the sleeve and the rotary spool, the supply groove on the rotary spool side, the left / right control groove on the sleeve side, the left / right communication groove on the rotary spool side, and the left / right communication groove on the sleeve side. The communication area with the discharge groove is controlled by the chamfer of the control protrusion on the rotary spool side, and the fitting part between the left and right control groove on the sleeve side and the left and right communication groove on the rotary spool side is overlapped. To form a block portion that blocks the oil flow, and the flow of hydraulic oil from the supply groove and the left / right communication groove on the rotary spool side to the left / right control groove and the discharge groove on the sleeve side , Is that one was also an up-flow ".

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A control valve according to the present invention will be described below with reference to an embodiment shown in FIG. As shown in a partially developed view of FIG.
Has a supply port 103 for supplying pressure oil and left and right control grooves 104 formed on both sides of the supply port for supplying pressure oil to control ports 104 and 105 connected to the power cylinder.
A, 105A, cylinder control protrusions 106B, 107B on the circumference of the control groove, on which communication ports 106, 107 connected to the power cylinder are bored, and further on the circumference of the cylinder control protrusion. And discharge grooves 108A and 109A into which the discharge oil of the power cylinder flows.

The rotary spool 102 has a supply groove 103A facing the supply port 103, and the left and right control grooves 104A, 105 on both sides of the supply groove 103A.
A control convex portion 104 provided with a chamfered portion (corresponding to 40 in FIG. 5) facing A and controlling the supply of pressure oil to the left and right control grooves.
B, 105B, and left and right communication grooves 106A, 106A outside the control projection and facing the communication ports 106, 107.
107A and the discharge groove 1 further outside the left and right communication grooves.
08A, 109A and discharge port 10 to tank
The control projections 108B and 109B formed with the holes 8 and 109 are formed.

A plurality of pairs of control portions X (three sets in FIG. 1) formed by fitting the two formed so as to be relatively rotatable relative to each other are formed on the circumference, and a sleeve 101 and a rotary spool 102 are formed. With the relative rotation of the supply spool 103A on the rotary spool side and the left and right control grooves 1 on the sleeve side.
04A, 105A and the left and right communication grooves 106A, 107A on the rotary spool side and the discharge grooves 108A on the sleeve side.
While the aperture control is performed by a chamfered portion (corresponding to 40 in FIG. 5) of the control protrusion on the rotary spool side so as to gradually change the communication area with 109A, the end faces E, E of the control protrusions 104B and 105B on the rotary spool side are controlled. F and the control protrusions 106B and 107B on the sleeve side overlap each other to form a block portion that blocks the flow of oil.

Next, when the sleeve 101 and the rotary spool 102 are relatively displaced in the direction of the arrow in FIG. 2, the variable throttle portions A and C gradually expand, while B and D gradually narrow. At this time, the flow direction of the oil from the supply spool 103A to the left and right control grooves 104A and 105A and the flow direction from the left and right communication grooves 106A and 107A to the discharge grooves 108A and 109A are both from the rotary spool 102 side to the sleeve. This is a so-called upflow to the 101 side.

In the case of the prior art shown in FIG. 4B, the flow from the control grooves 28, 35 to the discharge grooves 12, 18 is a so-called downflow from the sleeve side to the rotary spool side, contrary to the present invention. The oil flows along the chamfered portion 40 in the narrow passage sandwiched between the chamfered portions 40 of the control protrusions 19 and 26 on the rotary spool side and the inner wall surfaces of the control protrusions 12A and 18A on the sleeve side. The flow separates from the end surface of the chamfered portion 40 on the rotary spool side and the inner wall surfaces of the control protrusions 12A and 18A on the sleeve side, and the turbulent flow is generated. Although it is easy to generate and the generation of fluid noise increases, in the case of the present invention, the oil flows to the control groove or the discharge groove formed in the wide passage along the chamfered portion of the control convex portion, so that the flow is Remove from chamfer There also difficult that turbulence is unlikely to occur, generation of cavitation is suppressed, it is possible to reduce the occurrence of fluid noise.

[0021]

As described in detail above, in the present invention,
The flow direction of the oil is changed from the supply groove 103A to the left / right control groove 104.
A, the flow direction to 105A, and the left and right communication grooves 106A,
In both the flow directions from 107A to the discharge grooves 108A and 109A, the sleeve 1
This is an upflow to the 01 side. As a result, since the oil flows to the control groove or the discharge groove formed in the wide passage along the chamfered portion of the control projection, the flow is less likely to be separated from the chamfered portion, and turbulence is less likely to occur, so that the cavitation may occur. The generation of fluid noise can be suppressed, and the generation of fluid noise can be reduced.

[Brief description of the drawings]

FIG. 1 is an equivalent view of a control valve of the present invention.

FIG. 2 is a partially developed view of the control valve of the present invention.

FIG. 3 is a cross-sectional view of a control valve and an output portion of a rack and pinion according to the related art.

FIG. 4A is an equivalent view of a control valve according to the related art. (B) It is a partial development view of the control valve concerning a prior art.

FIG. 5 is an enlarged view of a chamfer of a control valve according to the related art.

FIG. 6 is an equivalent circuit diagram of a control valve according to the related art.

[Explanation of symbols]

 P Hydraulic pump V Rotary valve 101 Sleeve 102 Rotary spool 103 Supply port 103A Supply groove 104, 105 Power cylinder control port 104A, 105A Left / right control groove 104B, 105B Control projection 106, 107 Power cylinder communication port 106A, 107A Left / right communication Grooves 106B, 107B Cylinder control protrusions 108, 109 Discharge ports 108A, 109A Left and right discharge grooves 108B, 109B Discharge side control protrusions

Claims (1)

[Claims] 1. A stub shaft that rotates integrally with a steering wheel, an output shaft that links to a steering mechanism, a torsion bar that links both shafts, a rotary spool that switches according to the relative rotation of the two shafts, and A rotary valve comprising a sleeve, a supply port for supplying pressure oil from a hydraulic pump on the sleeve side, left and right control grooves formed on both sides of the supply port for supplying pressure oil to the power cylinder, A cylinder control convex portion provided outside the control groove and provided with a communication port connected to the power cylinder, and a discharge groove into which oil discharged from the power cylinder flows further outside the cylinder control convex portion. On the rotary spool side, a supply groove facing the supply port on the sleeve side, and right and left shafts facing the control groove. A supply-side control projection provided with a chamfer for controlling the supply of pressure oil to the cylinder control groove, left and right communication grooves facing the communication port, and a discharge port to the tank facing the discharge groove are provided. Formed on the circumference, and a pair of control portions formed by fitting the two to be rotatable relative to each other are formed on the circumference. The communication area between the supply groove on the spool side, the left and right control groove on the sleeve side, and the left and right communication groove on the rotary spool side and the discharge groove on the sleeve side is controlled by the chamfered portion of the control projection on the rotary spool side. A fitting portion between the left and right control grooves on the sleeve side and the left and right communication grooves on the rotary spool side is overlapped to form a block portion for blocking oil flow, and the rotary spool side supply groove is formed. Control valve of a hydraulic power steering apparatus characterized by the flow of hydraulic oil to the groove and right and left control sleeve side from the left and right contact grooves grooves and discharge grooves were all up-flow.