JPH03612Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an electrohydraulic valve that changes an aperture opening area in accordance with a control current applied to a solenoid.

<Prior Art> As shown in FIG. 3, a conventional electromagnetic hydraulic valve of this type controls a control spool 2 in an upward direction, that is, in a yoke 3 by applying a control current to a solenoid 1.
By displacing the control spool 2 toward the side, the opening area of the orifice 4 is changed to control pressure, flow rate, etc.

In this case, the lower end of the control spool 2 has a fourth
A notch 6 having the shape shown in the figure is formed, and the opening area of the orifice 4 for the control current to the solenoid 1 gradually increases with upward displacement as shown by the broken line in Figure 5. Displaced with the characteristics of

<Problems to be solved by the invention> However, depending on the application, characteristics that are opposite to the current situation may be required as shown by the solid line in Figure 5.
It is necessary to process the material into a slit in the middle of the process, which is difficult to process, and requires special processing methods such as electrical discharge machining.
The disadvantage is that processing costs are high.

<Effects of the invention> The present invention has been made to solve the above-mentioned drawbacks of the conventional technology, and includes a control spool that is located on the yoke side and a first spool that is attracted to the yoke, and a first spool that is fitted into the first spool. A second spool that is fitted to the shaft portion, and a notch that gradually becomes wider as the second spool is displaced in the yoke direction is formed on the end surface that comes into contact with the first spool. This invention relates to an electromagnetic hydraulic valve.

<Operation> Since the present invention has the above configuration, by applying a control current to the solenoid, the control spool is attracted toward the yoke and displaced upward.

At this time, since the second spool constituting the control spool is formed with a notch that gradually becomes wider as it is displaced toward the yoke, as shown in FIG. A characteristic in which the opening area of the orifice gradually decreases can be obtained.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. In FIG. 1, 10 indicates a valve body;
This valve body 10 includes a valve sleeve 11 made of a magnetic material and provided with a mounting flange portion 11a, and a support sleeve 1 made of a non-magnetic material fixed to the outer periphery of the sleeve portion of the valve sleeve 11 by brazing.
2, a spacer ring 13 made of a non-magnetic material that is fitted and fixed within the support sleeve 12 and abuts the outer end of the sleeve portion of the valve sleeve 11, and a stepped inner hole bored in the center of the lower end of the valve sleeve 11. The end sleeve 14 is made of a non-magnetic material and is fitted and fixed to protrude. This valve body 10 has an inner hole 20a provided in a mounting base 20.
The end sleeve 14 is fitted therein in a fluid-tight manner and fixed by screwing.

The mounting base 20 has a pair of fluid passages 21 and 22.
is bored, and one fluid passage 21 is connected to the inner hole 20.
The other fluid passage 22 is open to the side of the inner hole 2.
It opens at the bottom of 0a. The fluid passage 21 is connected to the end sleeve 14.
A radial fluid passage 14a communicating with an annular groove 14b formed in the inner wall of the inner hole 20a is bored.
The bottom of the end sleeve 14 is communicated with the inside of the end sleeve 14 through a through hole 23a formed in the center of a stopper 23 fixed to the lower end of the end sleeve 14.

A sleeve-shaped yoke 25 made of a magnetic material is attached to the support sleeve 12 of the valve body 10 with a spacer ring 13 in between, and a screw shaft 27 is screwed into the yoke 25 so that its position can be adjusted.

On the other hand, the valve sleeve 11 and the spacer ring 13
A control spool 30 is fitted into the inner hole 10a of the valve body 10 formed by each inner hole of the end sleeve 14, and is slidably fitted into the spacer ring 13 and the end sleeve 14. Between the control spool 30 and the screw shaft 27,
A spring 18 is fitted, and the spool 30 is normally positioned at the lower end where the lower end of the control spool 30 abuts the stopper 23. A solenoid 17 is attached to the outer periphery of the support sleeve 12 and the yoke 25 to raise the control spool 30 against the repulsive force of the spring 18.

The control spool 30 is located on the yoke 25 side and is a first spool 3 that is attracted to the yoke 25.
1, and a cylindrical second spool 41 located on the stopper 23 side. This first spool 3
1 has a fitting shaft portion 32 at its lower end as shown in FIG.
A large-diameter hole 33 having a predetermined depth from the lower end of the fitting shaft portion 32 and a communication hole 34 opening from the radial direction to the large-diameter hole 33 are formed, and a second spool 41 has a plurality of notches 42 whose upper portions are wider on the end surface side in contact with the first spool 31.
is formed.

By integrally connecting the first and second spools 31 and 41, an orifice 50 is formed between the notch 42 and the stepped surface 35 of the first spool 31.

According to the electrohydraulic valve configured in this way, when no control current is applied to the solenoid 17,
The control spool 30 is positioned at the lower end by the repulsive force of the spring 18, and the orifice 50 has the maximum aperture opening area as shown by the solid line in FIG.

Thereafter, when a control current is applied to the solenoid 17, the solenoid 17 moves through the cover 28, the valve sleeve 11 of the valve body 10, and the control spool 30.
A magnetic flux passing through the first spool 31, yoke 25, cover 28, and solenoid 17 is formed, and thereby an attractive force acts on the control spool 30.
As a result, the control spool 30 is displaced upward, and as a result, the aperture area of the orifice 50 gradually decreases as the current applied to the solenoid 17 increases, as shown by the solid line in FIG. Become.

<Effects of the Invention> As detailed above, the present invention has a control spool located on the yoke side and a first spool that is attracted to the yoke, and a first spool that is fitted into the fitting shaft of the first spool. 2 spools, and a notch that gradually becomes wider as the second spool is displaced in the yoke direction is formed on the end surface that comes into contact with the first spool. The notch can be formed easily and at low cost, and has the advantage that, for example, characteristics such as decreasing the aperture opening area in response to an increase in applied current can be easily accommodated.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the electrohydraulic valve of the present invention, FIG. 2 is a partial view showing the assembled state of the control spool, and FIG. 3 is a longitudinal sectional view of a conventional electrohydraulic valve.
Figure 4 is a partial diagram showing a conventional control spool;
The figure is a graph showing changes in the opening area of the orifice. 10... Valve body, 17... Solenoid, 1
8...Spring, 25...Yoke, 30...Control spool, 31...First spool, 41...Second
Spool, 42...notch.

Claims (1)

[Scope of utility model registration request] a valve body having an inflow port and an outflow port and forming an inner hole through which these ports open; a control spool that changes a passage opening area between both ports; a spring that biases the control spool in a direction to close a passage communicating between both the ports; and a spring that is disposed coaxially with the control spool on the valve body. a solenoid wound around the outer periphery of the yoke and to which a control current is applied, so that the axial displacement of the control spool is brought about by the attractive force of the yoke generated in response to the current applied to the solenoid. In the electrohydraulic valve according to the present invention, the control spool includes a first spool that is located on the yoke side and is attracted to the yoke, and a second spool that is fitted to a fitting shaft of the first spool, This second
An electrohydraulic valve characterized in that a notch that gradually becomes wider as the spool is displaced in the yoke direction is formed on the end surface that comes into contact with the first spool.