JPS624774Y2 - - Google Patents

Description

[Detailed description of the invention] This invention has a valve body and a solenoid part with a movable core connected to the valve body, and the attraction force of the electromagnet in the solenoid part is proportional to the input current value. The present invention also relates to an electromagnetic proportional control valve that operates almost constantly regardless of stroke.

This type of conventional control valve, which is configured so that the movable core operates proportionally by increasing or decreasing the current value flowing through the electromagnetic coil, has a fixed member made of a magnetic material that attracts the movable core when the electromagnetic coil is energized. Between the cylindrical fixed core that accommodates and guides the movable core,
A structure in which the fixed member and the cylindrical fixed core are concentrically and integrally connected by interposing a cylindrical non-magnetic material having the same inner diameter as the inner diameter of the annular end face of the fixed member and the cylindrical fixed core. Are known.

However, in this type of conventional structure, the magnetic material and the non-magnetic material are formed into an integral cylindrical shape by brazing or welding. In addition to requiring machining, wet type solenoids also have drawbacks such as oil leakage or lack of pressure resistance due to poor brazing or welding.

The purpose of this invention is to provide an improved electromagnetic proportional control valve that does not require special machining, does not leak oil, and has excellent pressure resistance.

For this purpose, in the electromagnetic proportional control valve according to the invention, a cylindrical fixed core having a fixed suction end at one end constituting a fixed member and accommodating a movable core therein has a continuous inner circumferential surface, and A portion of the shaped fixed iron core near the fixed suction end is formed circumferentially thin enough to substantially cut the magnetic flux, and a non-magnetic material is fixed to this circumferentially thinly formed portion. This part may preferably be formed into a circumferential groove.

An embodiment of this invention will be described below with reference to the drawings.

FIG. 1 schematically shows the main parts of the solenoid section of the electromagnetic proportional control valve according to this invention.

In the drawings, reference numeral 1 denotes a rod to which a movable iron core 2 is attached, one end of which is connected to a valve body (not shown). 3 is a cylindrical fixed iron core, and one side thereof is provided with a fixed suction end 3a. 4 is a cylindrical fixed core 3
It is an electromagnetic coil wound around the outer circumference of the According to this invention, the cylindrical fixed core 3 has a continuous inner peripheral surface 3b that accommodates the movable core 2 therein, and a portion 3c near the fixed suction end 3a has a large magnetic resistance, that is, the fixed core 3 It is circumferentially thin enough to substantially cut the magnetic flux passing through it. This can be formed, for example, by cutting part 5 from the outer circumferential part. A filler 5 made of a non-magnetic material is fixed to this thin circumferential portion 3c. With this configuration, when the electromagnetic coil 4 is energized, the attractive force continues to rise while the movable core 2 begins to stroke due to the magnetic force and is displaced to the vicinity of 5a, and then the end surface 2a of the 2 moves toward the non-magnetic material 6. The suction force remains constant regardless of the stroke until it hits.

As explained above, in the electromagnetic proportional control valve according to this invention, the inner circumferential surface of the cylindrical fixed core forms a continuous surface. There is no need to re-machine the inner peripheral surface of the cylindrical fixed core after the joining process by brazing or welding.
It is possible to reduce production costs and improve productivity by reducing the number of production processes, and since it has a continuous inner circumferential surface with no joints, there is no risk of oil leakage when used as a wet type solenoid. Excellent effects such as high pressure resistance can be obtained. However, in theory, it is not possible to completely block the magnetism, so the efficiency of the attraction force is slightly reduced.As shown in Figure 2, although the 3c part has been removed and the magnetism can be completely blocked, the attraction force still remains. It is undeniable that there is a certain degree of slope in the parallel part of the suction force, as shown by the dotted line, compared to the state shown by the solid line showing the change, but in the current precision control system that controls the position by feedbacking the position using sensors, etc. Since there is almost no effect due to changes in suction force, no practical problems arise.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of this invention. FIG. 2 shows the relationship between the stroke of the solenoid and the attraction force, and the solid line shows the change when all the parts 3c are also made of non-magnetic material, and the dotted line shows the case of the present invention. In the figure, 1: rod, 2: movable core, 3: cylindrical fixed core, 3a: fixed suction end, 3b: continuous inner peripheral surface, 3c: thin circumferential portion, 4: electromagnetic coil, 5, 6: Non-magnetic material.

Claims (1)

[Scope of utility model registration request] It consists of a valve body and a solenoid part with a movable iron core connected to the valve body, so that the attraction force of the electromagnet in the solenoid part acts almost constantly in proportion to the input current value and is independent of the stroke. In the electromagnetic proportional control valve configured, the cylindrical fixed core has a fixed suction end on one side, a continuous inner circumferential surface that accommodates a movable core inside, and an electromagnetic coil is wound around the outer periphery of the fixed suction end. An electromagnetic proportional system characterized by forming a thin circumferential part of the near part to the extent that it substantially cuts the magnetic flux, and providing a non-magnetic material around the outer periphery of this thin circumferential part to make it almost uniform in thickness. control valve.