JPH04133978U - Spool valve of rotation control valve of power steering device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a spool valve for a power steering device with a control edge surface that enables the desired supply and discharge of pressure oil in the power steering device and has the desired control characteristics in a single process. provide. [Structure] The spool valve 1 is provided with a control edge surface that is parallel to the long groove over substantially the entire length of the long groove and is rectangular in plan view, the machining of the control edge surface is perpendicular to the longitudinal direction of the long groove, and The edge surface has at least one circular arc portion 20 having a concave shape in the cross section of the valve body.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention connects the input shaft and output shaft via a torsion bar, and A spool valve that rotates and has a long groove for supplying and discharging pressure oil from a hydraulic pump; It consists of a valve body that loosely fits into the pool valve and is fixed to the output shaft. The dee is provided with a long groove corresponding to the pressure oil supply/discharge groove of the spool valve, and the output The spool against the valve body is twisted by the torsion bar according to the load on the shaft. The opening amount of the long supply/discharge groove between the spool valve and the valve body is controlled by the relative angular displacement of the valve. control element that controls the flow of pressure oil to the hydraulic cylinder that operates the output shaft system. A spool valve for a rotation control valve of a power steering device, which has a long groove with a groove surface. Regarding.

0002

[Conventional technology]

This type of spool valve is used in rack and pinion power steering equipment. The input shaft is connected to the steering wheel of the vehicle, and the output shaft is connected to the pinion. or As is well known, in ball nut type power steering devices, the input shaft is the hub of the car. The output shaft is connected to the ball nut shaft. spool here The valve is powered by pressure oil from a hydraulic pump driven by an automobile's internal combustion engine, for example. The hydraulic cylinder that hydraulically operates the output shaft side of the steering device is connected to the Supply and discharge according to the following. In this case, the supply and discharge of pressure oil is In low speed ranges such as when traveling on the ground or parking in a garage, or when stopped, increase the size of the steering wheel. While reducing the operating force, the steering wheel should be moderately heavy for driving stability in high-speed driving ranges. Since pressure oil is required, pressure oil is not supplied to or discharged from the hydraulic cylinder. Therefore, it is necessary for automobile operation to be accompanied by manual operation. In order to improve steering characteristics, especially in high-speed driving ranges, we have improved the steering wheel rigidity and reduced the angle of the steering wheel. There is a need to improve the characteristics of steering devices in the steering range, that is, in the low hydraulic pressure range. Therefore, in the well-known technology, in order to increase the rigidity of the steering wheel when driving straight, By adding a spring reaction force mechanism or adding a vehicle speed sensor to the vehicle, the steering force can be changed depending on the vehicle speed. On the other hand, align the control edge surface of the long groove of the spool valve against the outside of the spool valve. One or two steps of rectangular slopes each having a predetermined angle extend approximately the entire length of the groove. On the other hand, the control edge can be machined at the same time as hobbing to form the groove of the spool valve. The control edge surface of a spool valve that forms a pressure oil control valve. has a complex shape. However, the control edge surface with rectangular slope In this case, the opening area is proportional to the relative rotation angle of the spool valve to the valve body. Due to the large rate of change, the desired control characteristics can be achieved as the pressure increases from a low pressure region to a high pressure region. It is difficult to obtain the desired control characteristics, and machining of sloped surfaces is not easy. In order to achieve this, each processing step must be highly precise, so It also has the disadvantage of increasing engineering costs. Furthermore, at the same time as hobbing to form the groove of the spool valve. When forming a control edge surface, the shape of the control edge surface is also limited by the radius of the groove. However, if the subsequent grinding process is considered, the shape will be further restricted. Therefore, the control edge surface formed in this way has the above-mentioned rectangular slope. Similar to the control edge surface with a surface, it was not possible to achieve the desired pressure control characteristics. . As a countermeasure for these problems, Japanese Patent Application No. 1982-79988 (Japanese Patent Application No. 57-198170) ), but in order to obtain the desired control characteristics, the long groove of the spool valve must be at least When forming one or more control edge surfaces and placing emphasis on high-speed performance, , the characteristics in the low speed range will deteriorate, but on the other hand, if you emphasize performance in the low speed range, The disadvantage is that the characteristics deteriorate. In addition, the pressure characteristics are determined by the steering torque from the low pressure region to the high pressure region. The increase in pressure relative to the torque should have a gentle slope and a long linear change. The change in the rise from the low pressure area to the high pressure area is also poor. Therefore, both high speed and low speed range When trying to improve the characteristics of a multi-stage control edge surface that approaches the target characteristics, Also, high machining accuracy is required, and the shape of many control edge surfaces is changed from convex to concave. It was difficult to process. Furthermore, as a processing method for the control edge surface of the spool valve, The grinding direction of the control edge surface is the axial direction of the spool valve, so the machining pattern of the grinding surface is Because it is perpendicular to the flow of pressure oil, it generates pressure oil flow noise. To prevent this , it is necessary to control the surface roughness of the ground surface of the control edge surface very strictly, which reduces the tool life. It is a short-lived and expensive processing method.

0003

[Problem that the idea aims to solve]

The present invention eliminates the drawbacks of the above-mentioned known technologies and provides hydraulic power for power steering devices. Control with desired control characteristics in a single process with desired supply and discharge The problem is to provide a spool valve for a power steering device with an edge surface. do.

0004

[Means to solve the problem]

The above-mentioned problem can be solved by the present invention, since the spool valve can be flattened over almost the entire length of the long groove. It is a row and has a rectangular control edge surface in plan view, and the machining pattern of this control edge surface corresponds to perpendicular to the longitudinal direction of the long groove, and the control edge surface is transverse to the valve body. This problem is solved by having at least one circular arc portion having a concave shape on the surface.

[0005]

【Example】

Next, the present invention will be explained in detail with reference to drawings showing embodiments.

[0006] As shown in Figure 1, the spool valve 1 of the rotation control valve is connected to an input shaft (not shown). loosely fitted into the valve body 2 connected to the output shaft (not shown) via the valve body 3. are doing. The valve body 2 is loosely fitted into the valve housing 4, and is connected to the input shaft and the output shaft. The power shaft is connected to the valve housing 4 or the power steering device connected to it. There is no relative movement in the radial direction due to bearings installed in the case. The arrow indicates the hydraulic port. This shows the supply and discharge of pressure oil from the valve housing 4. Pressure oil is supplied from the supply hole 5 through a ring-shaped groove formed on the surface, and the spool Pressure oil is pumped through a ring-shaped groove 6 formed between the valve 1 and the torsion bar 3. Drain into the pump oil sump. Holes 7 and 8 indicated by dotted lines and dashed-dotted lines are valve holes, respectively. power steering Pressure on the right or left side of the piston of the cylinder that hydraulically operates the output shaft side of the ring device connected to the room. In this case, a ring shape for controlling the supply hole 5 and the hydraulic cylinder is used. The grooves are provided at intervals in the axial direction of the valve body 4.

[0007] The spool valve 1 having a control edge surface consisting of a single circular arc R shown in FIG. It consists of a first control edge 9 and a second control edge 10, each indicated by an arrow 2, as shown in FIG. The first control edge 9 and the second control edge 10 are substantially in the long groove of the spool valve 1. It spans the entire length of 11. The control characteristics of this spool valve 1 are shown by the solid line in Fig. 10. As shown by the dotted line, the desired characteristic curve is approximately approximated to the desired characteristic curve. can be done. The first and second control edges 9, 10 correspond to the rotation half shown in FIG. It has a grinding surface equal to the circular arc portion 20 of radius R. The rotating shaft of the grinding tool is connected to the spool valve 1. The spool valve 1 is arranged parallel to the central plane 12 of the long groove 11 of the spool valve 1 as shown in FIG. The control edge surface of the long groove 11 is ground in two steps in the linear X and Y directions, and each step is Compared to the conventional machining method when the machining is done in one stage, it has a rotation radius R as shown in the figure. In the longitudinal direction of the long groove 11, a grinding tool having a cylindrical grinding surface e shown in FIG. In contrast, it is machined by a single operation of pressing a grinding tool rotating at right angles. As a result, the machining line of the control edge is perpendicular to the longitudinal direction of the long groove 11. Become. Each control edge surface machined into the long groove 11 of this spool valve 1 is This processing method is shown in FIG. 11.

[0008] In another embodiment of the invention shown in FIGS. 6 to 8, the control edge surface of the spool valve 1 is It consists of three control edges 13, 14, and 15 that are composed of a single circular arc. in this case, Control of the spool valve 1 with control edges 9, 10 consisting of a single circular arc of the first embodiment As shown by the dash-dotted line, the control characteristic approaches the desired control characteristic shown in Fig. 10. can be used. The control edges 13, 14, 15 of this spool valve 1 are shown in FIG. Processing is performed using a grinding tool 16 having the grinding surface e shown. In this case, as shown in Figures 6 to 8. The control edges 13, 14, 15 are formed by grinding with a grinding surface e shown in FIG. By appropriately selecting the rotation radius Rn, rn of the cutting tool, the arc-shaped control surfaces 21, 2 form 2. This process is parallel to the center plane 12 of the long groove 11 of the spool valve 1. The grinding tool 16 is rotated perpendicularly to the long groove 11 using a grinding tool 16 having a rotating shaft. Processing is performed by pressing the grinding tool 16. Each control edge surface of the spool valve is Processed by indexing.

[0009] The control edge of the spool valve 1 according to the present invention is made with a grinding tool as shown in Fig. 5. , such shaped grinding tools may be made of Porazon material or diamond. In particular, when it is made of diamond, it can be used for a long period of time. More than Thus, the present invention allows the control edge surface of the spool valve 1 to have the desired characteristics in one processing step. can do.

0010 Figure 9 shows the opening area versus the relative rotation angle between the spool valve 1 and the valve housing 4. , where the solid line is the desired curve and the dotted line is the first embodiment of the invention. shows the characteristics of a spool valve with a control edge surface consisting of a single circular arc, and a single point chain The lines show the characteristics of the spool valve consisting of multiple circular arcs according to the present invention, and Fig. Shows the relationship of the hydraulic pressure to the hydraulic cylinder with respect to the force, where the solid line is the desired curve. The dotted line indicates the characteristics of the first embodiment, and the dashed line indicates the characteristics of the second embodiment.

[0011]

[Effect of the idea]

This invention enables the supply and discharge of pressure oil to the power steering device as desired. In addition, the control edge surface of the spool valve can be manufactured in a single process to achieve the desired control characteristics. It can be specially processed.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a spool valve of a power steering device according to the present invention.

FIG. 2 is an enlarged partial cross-sectional view of the first embodiment of the present invention.

FIG. 3 shows the direction of arrow A in FIG. 2;

[Fig. 4] Fig. 4 shows a control edge surface having an arc R and a conventional 2
Showing step control edge surface.

FIG. 5 shows an example grinding tool.

FIG. 6 is an enlarged partial cross-sectional view of the second embodiment.

FIG. 7 shows a view of arrow A' in FIG. 6;

FIG. 8 shows another embodiment as viewed from arrow A' in FIG. 6.

FIG. 9 shows the correlation between the relative rotation angle and the opening area of the spool valve.

FIG. 10 shows the correlation between steering force and pressure.

FIG. 11 shows a method of machining a control edge surface of a spool valve.

[Explanation of symbols]

1 Spool valve 2 Valve body 9, 10, 13, 14, 15 control edge 3 Torsion bar 4 Valve housing 5, 6 Pressure oil supply and discharge groove 7, 8 Supply and discharge grooves to hydraulic cylinders 11 Long groove 12 Center plane of long groove 16 Grinding tools 20, 21, 22 Arc-shaped control surface

Claims (1)

[Scope of utility model registration request] A spool valve that connects the input shaft and output shaft via a torsion bar, rotates together with the input shaft, and has a long groove for supplying and discharging pressure oil from the hydraulic pump, and a spool valve that loosely fits into the spool valve and is fixed to the output shaft. The valve body is provided with a long groove corresponding to the pressure oil supply/discharge groove of the spool valve, and the relative relationship of the spool valve to the valve body is A power steering device that has a long groove with a control edge surface that controls the opening amount of the supply/discharge long groove between the spool valve and the valve body by angular displacement, and controls the flow rate of pressure oil to the hydraulic cylinder that operates the output shaft system. In the spool valve of the rotation control valve, the spool valve has a control edge surface that is parallel to the long groove over substantially the entire length of the long groove and is rectangular in plan view, and the machining of this control edge surface is perpendicular to the longitudinal direction of the long groove. A spool valve for a rotation control valve of a power steering device, wherein the control edge surface has at least one concave arc portion in a cross section of the valve body.