JPS6047025B2 - How to chamfer a valve rotor for a hydraulic rotary valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic rotary valve used, for example, in a power steering system, and more particularly to a method for forming a chamfer on the drooping edge of a groove in a valve rotor.

Hydraulic rotary valves used in power steering devices, etc. have a valve rotor with a plurality of axial grooves formed therein, and are rotatably fitted around the outer periphery of the valve rotor. The valve sleeve has axial grooves that overlap each other on both sides, and the supply and discharge of pressurized fluid to and from the power cylinder is controlled in accordance with the relative rotational displacement between the valve rotor and the valve sleeve.

Since the hydraulic characteristics of the rotary valve are determined by the shape of the portion where the grooves of both the valve rotor and the valve sleeve overlap, the shape of the grooves of the valve rotor is determined in order to obtain the optimum steering force characteristics. 2. Description of the Related Art Hydraulic rotary valves have been known in which a chamfered portion of a predetermined shape is formed on the end edge of a raindrop.
Various methods have been used to form the chamfered portions of the grooves of the valve rotor, and the most common method is to perform grinding using a surface grinder.
According to this method, each groove must be ground sequentially, which increases the processing time.Also, it is impossible to perform curved chamfering, so it is difficult to obtain suitable steering force characteristics. It was difficult to obtain.

For this purpose, a method has been proposed in which a chamfer is formed by plastically deforming the material by pressing a tool into the groove, without using methods such as grinding or cutting (Japanese Patent Publication No. 52-4807
, JP-A-53-9516 Hemorrhoids). However, with either method, it is necessary to use the same number of tools as the grooves formed in the valve rotor, or to perform multiple steps with a single tool, which requires a large number of tools. This is not desirable in terms of cost, and molding through a large number of steps is not desirable in terms of production efficiency. The present invention has been made in view of the above points, and has a plurality of pairs of bulges extending in the axial direction spaced apart from each other at intervals substantially equal to the width of each groove of the valve rotor. Using the formed shifting tool, after arranging the axes of both the shifting tool and the valve rotor in parallel and aligning the pair of bulges with the grooves of the valve rotor, while pressing the shifting tool, A valve that can efficiently form a chamfered part by rolling it with a device having a simple configuration, and furthermore, can form this chamfered part into a desired shape to obtain a hydraulic rotary valve with good hydraulic characteristics. A method for chamfering a rotor is provided.

The present invention will be explained below based on illustrated embodiments.

FIG. 1 is a simplified explanatory view showing the process of chamfering the grooves of a valve rotor by the method of the present invention, and the center of the figure is a cross section perpendicular to the axis of the valve rotor 1 before the chamfer is formed. shows. This valve rotor 1 is conventionally known, and although its details are not shown, an even number of axial grooves 2, such as 4, 6, or 8, are formed at equal intervals on the outer circumferential surface. Together with a valve sleeve that is rotatably fitted around the outer periphery of the valve rotor 1 and has a plurality of axial grooves that overlap on both sides of the groove 2 in the circumferential direction, a hydraulic rotary valve is constituted. Even if the grooves 2 of the valve rotor 1 are not equally spaced, it is possible to construct a rotary valve by forming the grooves of the valve sleeve to correspond to these grooves 2. On both sides of the valve rotor 1, the shaft center is attached to the valve rotor 1.
A pair of rolling tools 3 and 4 are arranged parallel to the axis of the rolling tool.

These rolling tools 3 and 4 have a width W of the groove 2 of the valve rotor 1.
A pair of bulging portions 5, 5 are formed which protrude in the radial direction and extend in the axial direction, spaced apart from each other at approximately equal intervals. Further, these bulging portions 5, 5 are provided on the entire outer periphery of the tools 3, 4 at intervals equal to the circumferential distance ^1 of each groove 2 of the valve rotor 1. Therefore, the pair of bulges 5 of the tools 3 and 4
, 5 and one of the grooves 2 of the valve rotor 1, and then rotate both tools 3, 4, so that each groove 2 and each pair of bulges 5, 5 always rotate in correspondence with each other. It's getting old. When an even number of axial grooves 2 are carved around the entire circumference and chamfering is performed on the valve rotor 1, the bulging portions 5 of the rolling tools 3 and 4 having the above configuration are
At the position where the groove 2 of the valve rotor 1 corresponds, both tools 3,
4 clamps the valve rotor 1 from both sides, and in this state the tools 3 and 4 are rolled.

As a result, both wall edges 6 of the groove 2 are pressed by the bulges 5 of the tools 3 and 4, and a chamfer 7 is recessed in the same shape as the ring of the bulge 5 (see FIG. 2). is formed. Since the chamfered portion is formed by rolling in this manner, processing can be performed in a short time, and the efficiency of manufacturing the valve rotor 1 can be improved. In addition, since the axis of the valve rotor 1 and the axes of the tools 3 and 4 are arranged parallel to each other and rotated, it is necessary to carry out multiple pressing steps to finish the chamfered portion 7 with high precision. However, it is extremely efficient compared to conventional methods, which only require continuous rotation. Moreover, the shape of the chamfered portion 7 can be made into any shape such as a curved shape by appropriately setting the ring portion of the bulged portion 5, unlike when it is formed by means such as grinding. It is also easy to improve the hydraulic characteristics to make them optimal. As described above, according to the method of the present invention, the chamfering process of the valve rotor can be carried out extremely efficiently, and furthermore, an arbitrary shape can be easily obtained, so that the hydraulic characteristics can be improved. .

[Brief explanation of the drawing]

FIG. 1 is an explanatory view showing one embodiment of the method of the present invention, and FIG. 2 is a sectional view showing an example of a chamfered portion processed by the method of the present invention. 1... Valve rotor, 2... Valve rotor groove, 3, 4... Tool, 5... Tool bulge, 6... ... Edges of both walls of the groove, 7... Chamfered portion, W... Groove width, 1... Circumferential interval between grooves.

Claims (1)

[Claims] 1. In a method of chamfering both wall edges of each groove of a valve rotor for a hydraulic rotary valve in which a plurality of axial grooves are formed, chamfering is performed in the axial direction of a pair separated by an interval approximately equal to the width of each groove of the valve rotor. A rolling tool in which a plurality of pairs of extending bulges are formed at intervals equal to the spacing between the respective grooves is arranged so that its axis is parallel to the axis of the valve rotor, and the pair of bulges and the grooves of the valve rotor are parallel to each other. A method for chamfering a valve rotor for a hydraulic rotary valve, in which chamfers are formed on both wall edges of each of the grooves by arranging the grooves in correspondence with each other and then rolling the tool while pressing the grooves.