JPH0126541Y2 - - Google Patents

Description

[Detailed description of the invention] The invention relates to a spool type flow control valve,
In particular, the present invention relates to a spool-type flow control valve used as a control valve in a power steering device for vehicles such as automobiles.

It has a hollow part and is used as a flow control valve used in power steering devices of vehicles such as automobiles.
The valve body includes a valve body having an annular groove type valve port on an inner circumferential wall defining the hollow portion, and a spool valve fitted into the hollow portion and having an annular groove type valve port on an outer circumferential wall. Conventionally, there has been a spool-type flow control valve configured to change the degree of polymerization of the two valve ports by relative axial movement between the valve and the spool valve to control the flow rate of fluid flowing between the two valve ports. Are known.

In a power steering device, as the flow rate of hydraulic oil flowing from an oil pump into one cylinder chamber of a double-acting cylinder device for power steering via the above-mentioned flow control valve increases, it acts on the steering device. The assist force is increased, thereby reducing the steering force required by the driver, and the flow control valve responds to the steering operation by the driver, and when the steering is in a neutral (straight ahead) state, the flow control valve responds to the steering operation by the driver. The flow rate of the hydraulic oil flowing into the cylinder chamber is set to zero so that the cylinder device does not generate assist force, and when the steering changes from the neutral position to the right or left turning state, the hydraulic oil is supplied to the cylinder chamber. The cylinder device is controlled to generate assist force.

By the way, in the above-mentioned flow control valve, the side walls of the annular groove type valve ports provided on each of the valve body and spool valve are steep, and this extends to the general outer peripheral surface of the valve body or spool valve. If the steering wheel is extended, the moment both valve ports overlap each other even slightly, the flow rate of hydraulic oil flowing between these valve ports will suddenly increase, and this will cause the steering to change from a neutral state to a right or left turning state. Immediately, an excessive assist force is generated, making it impossible to obtain an appropriate steering feeling. For this reason, the peripheral edge along the side edge of the annular groove-shaped valve port of the spool valve is formed into a tapered shape, and the valve opening degree at the start and end of the valve opening/closing is finely controlled, so that the steering can turn to the right or left from the neutral state. Conventionally, it has been carried out to avoid generating an excessive assisting force as soon as the rotation state changes. In addition, in a region where the steering angle is relatively small, the assist force is generated at a predetermined ratio as the steering angle increases, and in a region where the steering angle is relatively large, the assist force is generated as the steering angle increases. In order to obtain the so-called two-stage bending characteristic, in which the assist force increases at a higher rate than when the turning angle is relatively small, the periphery along the side edge of the annular groove-shaped valve port of the spool valve. Conventionally, it has been considered to provide a relatively shallow annular groove in the annular groove and to form a peripheral edge along the side edge of the annular groove into a tapered shape.

Modifying the shape of the side edge portion of the annular groove type valve port as described above is effective in obtaining an appropriate steering feeling, but since the shape modification is performed over the entire circumference of the spool valve,
The shape modification dimensions have a very large influence on the flow control characteristics, and therefore, in order to obtain a flow control valve with the required flow control characteristics, the shape modification dimensions must be strictly controlled, and the actual In mass production, it is difficult to obtain processing accuracy that meets the requirements.

It has been considered to provide a cutout groove having an inclined bottom surface only in a circumferential portion of the side edge portion of the annular groove type valve port, thereby finely controlling the valve opening at the start and end of valve opening/closing. There is.
In this case, the degree of influence of the shape modification dimensions on the flow control characteristics is smaller than in the case where the shape modification described above is performed over the entire circumference of the spool valve, so the processing accuracy is not as strict. Although it is possible to obtain the required flow control characteristics without being controlled by A problem occurs.

The present invention is an improved system that can obtain the required flow control characteristics even if the processing precision of the side edge portion of the annular groove valve port is not very high, and does not generate large hydraulic fluid flow noise. The purpose is to provide a spool type flow control valve.

According to the present invention, in the spool-type flow control valve as described above, either the valve body or the spool valve has a peripheral edge along a side edge of the annular groove-type valve port tapered. This is achieved by a spool type flow control valve which is formed in the tapered peripheral part and has a notch part continuous with the annular groove type valve port in the tapered peripheral part partially formed in the circumferential direction of the tapered peripheral part. .

According to this configuration, in the small valve area where hydraulic oil flowing noise is generated, an oil passage is formed by the tapered peripheral portion, so that large hydraulic oil flowing noise is not generated, and the The tapered peripheral edge portion and the notch portion provide the above-mentioned two-step folding characteristic. Since the notch is not provided all the way around the valve body or spool valve, there is more margin in machining accuracy than if it were provided all the way around the valve body or spool valve, and the tolerance can be reduced. will be expanded and productivity will be improved.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a vertical sectional view showing one embodiment of the spool-type flow control valve according to the present invention, and FIG.
FIG. In the figure, 1
2 shows a valve body of a power steering control valve, and 2 shows a gear casing of a steering gear device.

The valve body 1 rotatably supports a main shaft 5 in a cylindrical hollow part 4 by a bearing 3. The main shaft 5 is connected to a steering main shaft (not shown) through a spline 6 formed at one end thereof, and is rotatably driven by a steering wheel. The main shaft 5 has a cylindrical shape, and a torsion bar 7 is inserted into the main shaft 5. The main shaft 5 and the torsion bar 7 are connected to each other by a knock pin 8 at one end of each.

The gear casing 2 rotatably supports a pinion 11 on the same axis as the main shaft 5 through bearings 9 and 10, and the pinion 11 has one end connected to a knock pin 12 at the other end of the torsion bar 7. They are connected together. The gear casing 2 also supports a rack bar 13 so as to be movable in its axial direction, and the rack bar 13 meshes with the pinion 11 at its rack 14.
is now being rotated. Rack bar 13
When the steering wheel is moved in the axial direction, a steering power cylinder (not shown), which is well known in itself, can supplementally apply an axial driving force (assist force).

A piston-shaped rack guide element 15 supported on the gear casing 2 is slidably engaged on the side of the rack bar 13 opposite to the rack 14, and this rack guide element 15 is connected to a screw cap 16.
The rack bar 13 is biased by the spring force of a compression coil spring 17 provided between the rack bar 13 and the rack bar 13.

The valve body 1 supports a cylindrical spool valve 18 in a cylindrical hollow portion 4 so as to be movable in the axial direction. The spool valve 18 has its outer peripheral surface in close contact with the inner peripheral surface of the valve body 1, and has annular groove type valve ports 19, 20, 21 on the outer peripheral wall.
are spaced apart from each other in the axial direction. The annular groove type valve port 19 is connected to a hydraulic port 22 formed in the valve casing 1, and is supplied with hydraulic pressure from the hydraulic port. The hydraulic port 22 is connected to a pump (not shown), from which a predetermined hydraulic pressure is supplied. The annular groove type valve ports 20 and 21 are respectively provided at equal positions apart from each other on both sides of the annular groove type valve port 19 in the axial direction, and the annular groove type valve ports 20 and 21 are provided at equal positions apart from each other on both sides of the annular groove type valve port 19.
24, is connected to a drain port 26 formed in the valve body 1 through the hollow part of the spool valve 18 and the hole 25. Further, annular groove type valve ports 27 and 28 are formed on the inner circumferential wall of the valve body 1. This annular groove type valve port 27,
28 are located at equal distances from each other on both sides of the hydraulic port 22 in the axial direction, and when the spool valve 18 is in the neutral position, each communicates with the annular groove type valve port 19 at one edge, and the Restrictions A and B are defined at the other edge, and the other edge communicates with annular groove-type valve ports 20 and 21, respectively, and restriction A' and B' are defined therebetween. The annular groove type valve port 27 is connected to a cylinder chamber on one side of a steering power cylinder (not shown) through a hydraulic pressure outlet port 29 formed in the valve body. Also, the annular groove type valve port 28
is connected to the cylinder chamber on the other side of the steering power cylinder via a hydraulic pressure outlet port (not shown) formed in the valve body 1.

The spool valve 18 has a notch 18' extending in the axial direction at one end thereof, and an engaging pin 3 attached to the pinion 11 is attached to this notch 18'.
1 is engaged. Notch 18' and engagement pin 31
Due to engagement with the spool valve 18, the pinion 1
1 for movement only in the axial direction. The spool valve 18 has a hole 32 in which a ball 33 is engaged. Ball 33 is secured to hole 32 by retaining ring 34.
It is restrained in a manner that allows it to rotate freely within the
It engages with a twisted groove 35 formed near the other end of the main shaft 5. When the steering force is transmitted from the main shaft 5 to the pinion 11 via the torsion bar 7 and the torsion bar 7 is twisted and a relative rotational displacement occurs between the main shaft 5 and the pinion 11, the ball 33 and the torsion groove 35 Due to the action of the spool valve 18
is displaced in the axial direction with respect to the pinion 11, in other words with respect to the valve body 1. In this case, for example, if the relative torsional displacement is a right-handed twist, the spool valve 18 will be displaced upward; on the other hand, if the relative torsional displacement is a left-handed twist, the spool valve 18 will be displaced upwardly. Displace downward. Also, a stopper piece 3 is provided at one end of the pinion 11.
6 is formed, and this stopper piece 36 cooperates with stopper surfaces 37, 38 of the main shaft 5 to limit the amount of relative torsional displacement between the main shaft 5 and the torsion bar 7. That is, the amount of axial displacement of the spool valve 18 is limited by the above-mentioned stopper mechanism.

When the spool valve 18 is displaced upward, the degree of restriction of the orifices A and B' decreases, the degree of restriction of the orifices B and A' increases, and the hydraulic pressure applied to the hydraulic port 22 is transferred to the annular groove valve port 19, the orifice. A, the oil pressure starts to be supplied to the cylinder chamber on one side of the steering power cylinder from the oil pressure outlet port 29 via the annular groove type valve port 27, and then the spool valve 1
8 rises above a predetermined value, the apertures B and A' become substantially closed. Spool valve 1
8 is displaced downward, the degree of restriction of the orifices B and A' decreases, the degree of restriction of the orifices A and B' increases, and the hydraulic pressure applied to the hydraulic port 22 is transferred to the annular groove valve port 19, the orifice B, Annular groove type valve port 2
8, the hydraulic pressure begins to be supplied to the cylinder chamber on the other side of the steering power cylinder from the oil pressure take-out port 30, and when the spool valve 18 is lowered by a predetermined value or more, the throttles A and B' are substantially closed. Become.

3 and 4 are enlarged views of the annular groove type valve port portion of the spool type flow control valve according to the present invention. The spool valve 18 has a tapered peripheral edge along both side edges of the annular groove type valve port 19, and has a notch 40 in a part of the tapered peripheral edge 39 in the circumferential direction. This notch 40 is provided from the side edge wall of the annular groove type valve port 19 to the middle of the tapered peripheral edge 39, and in this embodiment, the bottom wall of the notch is located at the spool valve 18. It is a plane containing an axis parallel to the axis.

As described above, by providing the tapered peripheral edge portion 39 and the partial notch portion 40 in the circumferential direction on the side edge portion of the annular groove type valve port 19, the degree of taper and size thereof can be determined as appropriate. As a result, the required two-step folding characteristics can be easily obtained.

By modifying the side edge shape of the annular groove type valve port as described above, in the small valve area where hydraulic oil flow noise occurs, the tapered peripheral edge 39
Since the oil passage is formed by the hydraulic oil passage, no loud hydraulic oil flow noise is generated. Since the notch 40 is provided only in a portion of the circumferential direction of the spool valve 18, its shape and dimensions have less influence on the flow rate control characteristics than if the notch 40 were provided all around the spool valve 18. Accordingly, there is a margin for machining accuracy and productivity is improved.

In the above embodiment, the shape of the side edge of the annular groove type valve port is modified by the spool valve 18.
Although this modification has been made to an annular groove type valve port provided in the valve body, this shape modification may also be made to an annular groove type valve port provided in the valve body.

Although the present invention has been described above in detail with reference to specific embodiments, it is understood that the present invention is not limited to this and that various embodiments are possible within the scope of the present invention. This will be obvious to businesses.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing one embodiment of the spool-type flow control valve according to the present invention, and FIG.
3 is a fragmentary sectional view showing an enlarged annular groove type valve port portion of the spool-type flow control valve according to the present invention; FIG. 4 is a sectional view taken along the line - in the figure; FIG. 4 is a spool-type flow control valve according to the present invention. FIG. 3 is a partial perspective view showing the spool valve taken out. 1... Valve body, 2... Gear case, 3...
... bearing, 4 ... cylindrical hollow part, 5 ... main shaft, 6 ... spline, 7 ... torsion bar,
8... Knock pin, 9, 10... Bearing, 11...
Pinion, 12...Knock pin, 13...Rack bar, 14...Rack, 15...Rack guide element, 16...Screw cap, 17...Compression coil spring, 18...Spool valve, 19-21...
Annular groove type valve port, 22... Hydraulic port, 2
3-25...hole, 26...drain port, 27,
28... Annular groove type valve port, 29, 30...
Hydraulic extraction port, 31... Engagement pin, 32...
Hole, 33...Ball, 34...Retaining ring, 35
... Groove, 36 ... Stopper piece, 37, 38 ... Stopper surface, 39 ... Tapered peripheral portion, 40 ... Notch.

Claims (1)

[Scope of utility model registration request] A valve body having a hollow portion and having at least one annular groove-type valve port on an inner circumferential wall defining the hollow portion, and at least one annular groove-type valve port fitted into the hollow portion and having an outer circumferential wall. a spool valve, the spool having a spool valve having a spool valve, the degree of polymerization of the two valve ports being changed by relative axial movement between the valve body and the spool valve to control the flow rate of fluid flowing between the two valve ports. In the type flow control valve, either the valve body or the spool valve has a tapered peripheral edge along a side edge of the annular groove type valve port, and the annular groove type is formed on the tapered peripheral edge. A spool-type flow control valve in which a notch portion continuous with a valve port is partially formed in the circumferential direction of the tapered peripheral edge portion.