JPH06179123A - Machining method for control valve body and electrode for electric discharge machining - Google Patents

Abstract

PURPOSE:To increase the dimensional accuracy of a groove in tangential direction which is formed in a valve sliding hole of a control valve body in circumferential direction. CONSTITUTION:After both sides of a groove formed in circumferential direction in a valve sliding hole 1b in which a spool 3 of a control valve body 1 is slid are pre-machined by turning to form grooves 1c and 1c', both side surfaces of the grooves 1c and 1c' are finished using an electric discharge electrode provided with a platy electrode section which has a tool width larger slightly than the width W of the groove 1c and can be inserted into the valve sliding hole 1b to obtain finished surfaces 1d, 1d, 1d', and 1d'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of machining a control valve body such as a servo valve or a proportional valve, and an electric discharge machining electrode.

[0002]

2. Description of the Related Art Conventionally, in order to secure high pressure resistance and durability with this type of control valve, it has been necessary to use a high hardness sleeve on the sliding surface of the spool.

FIG. 16 shows a schematic structure of a directional flow control valve usually called a servo valve. A high hardness sleeve 2 is fitted in a sleeve hole 1a of a body 1, and this sleeve 2
The spool 3 was slidably loosely inserted into the valve hole 2a forming the inner peripheral surface of the. The width A of the circumferential grooves 2b, 2b 'of the sleeve 2 which requires the most dimensional accuracy.
1 and B1 were machined with extremely high precision by a wire-cut electric discharge machining method or the like, and the interval C1 was also kept with high precision.

However, since the valve structure using such a sleeve has a low productivity of the sleeve and is extremely expensive, a control valve generally used as a proportional valve used in a relatively low pressure line, as shown in FIG. The body 1 which does not use a sleeve has been used by previously turning the circumferential grooves 1c and 1c 'formed in the valve sliding hole 1b of the spool 3 which is slid by casting.

[0005]

However, in such a conventional control valve body which has been turned, such a control valve body as shown in FIG.
Widths A2 and B2 of grooves 1c and 1c 'shown in FIG.
The dimensional accuracy of 2 is the width A of the grooves 2b and 2b 'shown in FIG.
Since the one-digit or two-digit accuracy is deteriorated by the dimensional accuracy of 1, B1 and the interval C1 thereof, the stroke of the spool is increased by almost one order to cover the deterioration of the accuracy.

For example, in the case of a high-precision body using a sleeve of high hardness with a sleeve processing accuracy of 0.01 mm, if a full spool stroke of 0.5 mm is required, a turning body with a processing accuracy of 0.1 mm is used. To be comparable, the result is a 5mm full spool stroke.
Actually, the full stroke of the control valve spool is 2-3 mm.
Since many of them are processed, the machining accuracy during turning was 0.05 mm, and machining was almost impossible.

Therefore, in a control valve having a body formed by turning, a spool is provided with a taper, a notch or the like so that the spool is overlapped or underlapped at its neutral position, and the flow rate gain is positively reduced to improve the processing accuracy. It covered the lowness. In this case, there is a problem that delicate control of the hydraulic pressure due to a slight change in the spool cannot be obtained, and the spool has a large stroke, resulting in poor responsiveness.

Therefore, in the hydraulic system using the control valve composed of the sleeveless turning body as shown in FIG. 17, the system accuracy is such that the hydraulic system using the control valve composed of the body having the highly accurate sleeve. It has been generally accepted that it is one or two orders of magnitude lower than the system accuracy of.

The present invention has been made in view of the above points, and an object thereof is to improve the dimensional accuracy of the groove in the axial direction by a simple processing method.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is characterized in that both sides of a circumferential groove formed in a valve sliding hole of a control valve body are pre-machined by turning, and then the valve is Insert the plate-shaped electrode portion of the electric discharge machining electrode into the sliding hole to a position where it can face the groove, and move the plate-shaped electrode portion at least in a direction orthogonal to the axis of the valve sliding hole for electric discharge machining,
The present invention provides a method for processing a control valve body for finishing at least a part of the side surface of the groove.

Further, an electric discharge machining electrode for finishing machining both side surfaces of a circumferential groove formed in the valve sliding hole of the control valve body in advance, and a plate-shaped electrode portion which can be inserted into the valve sliding hole. ,
There is also provided an electric discharge machining electrode including a shaft portion to which the plate electrode portion is attached. The plate-shaped electrode portion may have a disc shape or a rectangular plate shape, and may further have a protrusion or a recess.

[0012]

Since the control valve body machining method and the electric discharge machining electrode according to the present invention are as described above, in the machining method, the control valve body is formed in the valve sliding hole formed in advance by casting or the like. After pre-machining the groove in the circumferential direction by turning, both sides of the groove are finished by electrical discharge machining, so the machining time of electrical discharge machining is short and at the same time,
The dimensional accuracy of the groove in the axial direction can be significantly improved as compared with the conventional turning body.

Further, the electric discharge machining electrode used in the above machining method has a very simple structure including a plate electrode portion which can be inserted into the valve sliding hole and a shaft portion to which the electrode electrode is attached, so that it can be manufactured at a low cost. Can be supplied.

The disk-shaped plate-shaped electrode portion described above can finish a large surface with a small amount of movement, and the plate-shaped electrode portion can be moved in the axial direction by moving it. It is possible to partially increase the depth of the groove. Further, the plate-shaped electrode part having the protrusion or the recess formed therein can have the recess or the protrusion of any shape on the finished surface, and the control valve having the multistage flow gain characteristic can be easily obtained. it can.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a sectional view showing a main part of a control valve body processed by the processing method according to the present invention, FIG. 2 is a partially enlarged sectional view showing a groove part of a control valve body preprocessed by turning, and FIG. 3 is preprocessing. It is a side view which shows one Example of the electric discharge machining electrode which finish-machines the groove | channel of the formed circumferential direction.

This electric discharge machining electrode (hereinafter referred to as "electrode")
As shown in FIG. 3, 10 is composed of a disk-shaped plate-shaped electrode portion 11 having a diameter D1 and a tool width W1, and a shaft portion 12 that integrally attaches the plate-shaped electrode portion 11 to the tip portion. The diameter D1 of the plate-shaped electrode portion 11 is slightly smaller than the diameter D of the valve sliding hole 1b in which the spool 3 of the control valve body (hereinafter referred to as "body") 1 slides, and the tool width W1 is a preprocessed groove. It is set to be slightly larger than the width W of 1c.

4 (a) and 5 (b) are explanatory views showing a state in which the groove 1c preprocessed by using the electrode 10 is finished, and FIGS. 6 (a) and 6 (b). ) Is an explanatory view showing the finished surface. Now, in FIG. 1, the width W'of the grooves 1c and 1c 'which are formed at predetermined positions in the axial direction of the valve sliding hole 1b of the body 1 and whose groove widths have been widened by pre-processing and the finished finished surfaces 1d and 1d. It is assumed that the widths W of ′ are the same.

First, the plate-shaped electrode portion 11 of the electrode 10 is inserted into the valve sliding hole 1b of the body 1, and the plate-shaped electrode portion 11 of the electrode 10 is placed at a position facing the groove 1c as shown in FIG. Stop the axial movement. In this state, (a) and (b) of FIG.
As shown in FIG.
By displacing from b'to a point of radius r, both sides of the groove 1c are finished and the width W'of the pre-processed groove 1c is expanded to the width W. The width W of the finished groove is a dimension obtained by adding the discharge gap width Δ to both side surfaces of the tool width W1 of the plate-shaped electrode portion 11 of the electrode 10.

Then, the shaft center 10a of the electrode 10 is rotated in the direction of the arrow R at a radius r to finish both side surfaces of the groove 1c over the entire circumference to obtain finished surfaces 1d and 1d shown in FIG. After that, the shaft center 10a of the electrode 10 is displaced to a position coinciding with the axis 1b 'and moved in the direction of the axis 1b' to move the plate-shaped electrode portion 1
1 is made to face the groove 1c 'and the same finishing process is performed to obtain the finished surfaces 1d' and 1d 'shown in FIG.

In the machining method described above, the tool width W1 of the plate-shaped electrode portion 11 of the electrode 10 is pre-machined in the grooves 1c and 1c.
Although the width W'of c'is made larger so that both side surfaces are finished at the same time, the tool width of the plate-shaped electrode portion 11 is made smaller than the width of the preprocessed groove to move the electrode in the direction of the axis 1b '. It is also possible to finish the both side surfaces one by one.

FIG. 7 is an explanatory view showing such a processing method, and FIG. 8 shows the finished surface of the electrode 20.
The tool width W3 of the plate-shaped electrode portion 21 attached to one end of the shaft portion 22 is made smaller than the width W'of the preprocessed groove 1c, and the electrode 20 is vertically and horizontally located at a position where one side surface can be finished. After moving one side surface of the groove 1c by moving a distance g to (FIG. 8) and then moving in the direction of the axis 1e to finish processing the other side surface, the finished surfaces 1d and 1d are obtained. It is a thing.

Next, in FIGS. 9 (a), 9 (b), 9 (c),
(D) is an explanatory view showing another embodiment of the electrode according to the present invention, FIG. 10 is an explanatory view showing another processing method for finishing using this electrode, and FIG. 11 is an explanatory view showing its finished surface. FIG. 12 is a sectional view showing an example of a control valve using a body processed by this method.

The plate-shaped electrode portion 31 attached to one end of the shaft portion 32 of the electrode 30 has a groove 1c whose tool width W4 is preprocessed.
Is smaller than the width W ', and protrusions 31a and 31b having a width d and a height h are formed on both side surfaces thereof. At the time of finishing, the plate-shaped electrode portion 31 is inserted into the valve sliding hole 1b, and one side surface of the groove 1c having the width W1 pre-processed is stopped at a position where finishing can be performed, and is moved vertically and horizontally in FIG. After finishing one side surface of the groove 1c by finishing, one side surface of the groove 1c is moved in the direction of the axis 1e and the other side surface is finished to obtain finished surfaces 1d, 1d having a recess 1f with a depth h and a width of approximately d. .

According to this processing method, by processing the electrodes with high accuracy, it is possible to make the opening amount Q with respect to the stroke S of the spool 3 a two-stage gain as shown in FIG. . Needless to say, if the tool width of the plate-shaped electrode portion of the electrode used in this processing method is made larger than the width of the preprocessed groove, the axial movement of the electrode becomes unnecessary.

14 (a) and 14 (b) are explanatory views showing still another embodiment of the plate-shaped electrode portion, in which a rectangular plate-shaped electrode portion 41 is attached to one end of the shaft portion 42 of the electrode 40. I wore it. FIG. 15 is an explanatory view showing a processing method using the electrode 40 described above, and the shaft center 42a of the shaft portion 42 is inserted into the valve sliding hole 1b in a state shown by a virtual line eccentric from the shaft line 1e. , The plate-shaped electrode portion 41 is opposed to the pre-processed groove 1c and moved upward in the figure, and the shaft center 42a of the shaft portion 42 is rotated once clockwise in the state indicated by the solid line which coincides with the axis 1e. Both side surfaces of the groove 1c are finish-processed to obtain a finished surface 1d.

In this process, when the electrode 40 is temporarily stopped from rotating and fed in the direction of the axis 1e in a state where the longitudinal direction of the plate-like electrode portion 41 is horizontal, for example, in the figure, a partially deep recess 1
It becomes possible to form g, 1g '.

When the turning process which is the pre-process is highly accurate, it is obvious that only the partial recesses 1g and 1g 'need to be processed. If a recess having a predetermined width (such as the recesses 1g and 1g ') is machined in the axial direction from the turning surface, the flow rate is controlled only by this width, so that an arbitrary flow rate gain can be obtained depending on the electrode width. .

In each of the above embodiments, the electrode 1
0, 20, 30, 40 plate electrode parts 11, 21, 31,
The shape of 41 is a disk shape or a rectangular shape, but the shape is not limited thereto, and if it is a shape that can be inserted into the valve sliding hole 1b, for example, an elliptical shape, a disk shape eccentric from the shaft portion,
Alternatively, a square shape, a polygonal shape, or the like can be arbitrarily set as needed. Further, it is possible to provide not only one plate-shaped electrode portion but a plurality of plate-shaped electrode portions at a predetermined distance in the axial direction, and finish each groove simultaneously in one step.

[0029]

As described above, according to the method of machining the control valve body of the present invention, the circumferential groove formed in the valve sliding hole of the body is pre-machined by turning, and then both side surfaces of the groove are formed. Since the machining is done by electric discharge machining, the time required for electric discharge machining is extremely short, and at the same time, the dimensional accuracy of the groove in the axial direction is about one or two orders of magnitude larger than that of conventional turning bodies. Can be improved.

Further, since the electric discharge machining electrode used in the above machining method is composed of the plate-like electrode portion which can be inserted into the valve sliding hole of the body and the shaft portion thereof, the construction thereof is extremely simple and inexpensive. Can be supplied.

The above-mentioned plate-shaped electrode part in the shape of a disk is a rectangular plate-shaped product because it is possible to finish a large surface with a slight movement to improve workability. It becomes possible to partially increase the depth of the groove by moving the groove in the axial direction. Furthermore, by forming a projection or a recess on the plate-shaped electrode portion, a recess or projection of any shape can be formed on the finished surface, and a multi-stage flow gain characteristic can be easily obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of a control valve body processed by a processing method according to the present invention.

FIG. 2 is a partially enlarged sectional view showing a groove portion of the preprocessed control valve body.

FIG. 3 is a side view showing an embodiment of an electric discharge machining electrode for finishing both side surfaces of the groove.

FIG. 4 is an explanatory view showing a state in which the electric discharge machining electrode is similarly inserted into a valve sliding hole.

FIG. 5 is an explanatory view showing a finish processing state of the same.

FIG. 6 is an explanatory view showing the finished surface of the same.

FIG. 7 is an explanatory view showing another processing method according to the present invention.

FIG. 8 is an explanatory view showing a finished surface similarly processed by the processing method.

FIG. 9 is an explanatory view showing another embodiment of the electric discharge machining electrode according to the present invention.

FIG. 10 is an explanatory view similarly showing a machining method using the electric discharge machining electrode.

FIG. 11 is an explanatory diagram showing a finished surface of the same.

FIG. 12 is a sectional view showing an example of a control valve using a body similarly processed by the processing method.

FIG. 13 is a characteristic diagram similarly showing the relationship between the spool stroke and the opening amount of the control valve.

FIG. 14 is an explanatory view showing still another embodiment of the electric discharge machining electrode according to the present invention.

FIG. 15 is an explanatory view showing a machining method using the electric discharge machining electrode.

FIG. 16 is a cross-sectional view showing an example of a conventional control valve.

FIG. 17 is a sectional view showing another example of a conventional control valve.

[Explanation of symbols]

1 Control Body 1b Valve Sliding Hole 1c Pre-machined Groove 1d Finished Surface 1e Valve Sliding Hole Axis 3 Spool 10, 20, 30, 40 EDM Electrode 11, 21, 31, 41 Plate-shaped Electrode 12, 22 , 32, 42 Shafts 31a, 31b Projections

Claims (5)

[Claims] 1. A plate-shaped electrode portion of an electric discharge machining electrode is formed in the valve sliding hole after both sides of a circumferential groove formed in the valve sliding hole of the control valve body are pre-machined by turning. To a position that can be opposed to, the plate-shaped electrode portion is moved at least in a direction orthogonal to the axis of the valve sliding hole for electrical discharge machining,
A method of processing a control valve body, characterized in that at least a part of a side surface of the groove is subjected to finish processing. 2. An electric discharge machining electrode for finishing machining both side surfaces of a circumferential groove formed in a valve sliding hole of a control valve body in advance, and a plate-shaped electrode portion which can be inserted into the valve sliding hole. An electric discharge machining electrode comprising: a shaft portion to which the plate electrode portion is attached. 3. The electric discharge machining electrode according to claim 2, wherein the plate-shaped electrode portion has a disk shape. 4. The electric discharge machining electrode according to claim 2, wherein the plate-shaped electrode portion has a rectangular plate shape. 5. The electric discharge machining electrode according to claim 2, wherein a projection or a recess is formed on the plate-shaped electrode portion.