JPH0979412A - Solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep quantity of magnetic flux crossing a plunger constant in spite of the variation of source voltage, by forming an annular groove at the center peripheral part of the plunger. SOLUTION: Quantity of magnetic flux crossing a plunger 16 becomes constant by forming an annular groove 16a in the center part of the plunger 16 when source voltage is in a range between a prescribed value and the maximum value. Therefore, responsiveness of a solenoid valve 10 is kept invariable as attractive force of a coil device 12 to a plunger 16 is constant notwithstanding veriation of source voltage when it is exited. Actual position of the annular groove 16a formed at the center part of the plunger 16 is set not to change receiving parts of magnetism between a yoke 15 and the plunger 16 and between the plunger 16 and a core 11. That is, it is set in the position not to degrade the force of a coil device 12 for attracting the plunger 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve.

[0002]

2. Description of the Related Art A conventional solenoid valve, such as the one disclosed in Japanese Utility Model Laid-Open No. 7-034271,
When the coil device is excited, the plunger is attracted into the coil device, and the valve that moves integrally with the plunger opens the passage.

[0003]

However, in the solenoid valve described above, when the voltage applied to the coil device when the coil device is excited decreases, the attraction force of the coil device decreases and the responsiveness of the solenoid valve decreases. There was a problem that it was damaged. In particular, when performing PWM control (pulse wide modulation control), a decrease in responsiveness of the solenoid valve is a problem that cannot be overlooked because the elaboration of control is impaired.

Therefore, it is a technical object of the present invention to prevent the voltage fluctuation from affecting the plunger attraction force of the coil device.

[0005]

The technical means taken in the invention of claim 1 to solve the above technical problems are as follows:
A solenoid valve in which a plunger mounted in an axial hole of a yoke arranged in an inner peripheral portion of a coil device is axially displaced by excitation of the coil device, and a valve which moves integrally with the plunger opens and closes a passage. In the above, the annular groove is formed in the outer peripheral portion of the center of the plunger.

[0006]

In the above technical means, the magnetic path cross-sectional area is partially narrowed due to the existence of the annular groove, the amount of magnetic flux passing through the inside of the annular groove is limited, and even if the power supply voltage fluctuates, the plan The amount of magnetic flux passing through the jar can be kept constant.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawing FIG.

The solenoid valve 10 includes a magnetic core 11
Is provided. A coil device 12 is mounted on the right side of the core 11. The coil device 12 is integrally connected to the connector 13, and a pair of terminals 14 and 14 (only one of which is shown in the figure) projects rightward from the connector 13 so that the coil device 12 is connected to a power supply device (not shown). ing.

A magnetic material yoke 15 is closely fitted to the left inner peripheral portion of the coil device 12, and a magnetic material plunger 16 is disposed in the yoke 15. Plunger 1
A spring 17 is stretched between the core 6 and the core 11 so that the plunger 16 is always biased to the left.

On the left side of the plunger 16, a shaft 19 provided with a ball valve 18 is integrally provided, and the ball valve 1
8 is seated on the valve seat 20. Due to this seating, the passage 21 and the passage 22 (23) are blocked. When the coil device 12 is excited, a magnetic circuit is formed, and the magnetic force lines flow in the direction of the coil device 12 → yoke 15 → plunger 16 → core 11 → coil device 12. Due to the formation of this magnetic circuit, the plunger 16 moves to the spring 17
To the right (toward the core 11 side), the ball valve 18 separates from the valve seat 20, and the passage 21 and the passage 22 (2
3) communicates with.

An annular groove 16 is formed in the center of the plunger 16.
a is engraved, and the magnetic path cross-sectional area is partially narrowed. In other words, the amount of magnetic flux passing through the inside of the annular groove 16a is limited, and even if the power supply voltage fluctuates slightly, the plunger 16
The amount of magnetic flux passing through can be kept constant. Therefore, at the time of excitation, the force with which the coil device 12 attracts the plunger 16 is constant even if the power supply voltage fluctuates slightly, and the responsiveness of the solenoid valve 10 is maintained.

More specifically, when the power supply voltage is between the predetermined value and the maximum value, the annular groove 16a is formed in the center of the plunger 16 so that the amount of magnetic flux passing through the plunger 16 is constant. It is supposed to be
At the time of excitation, the force with which the coil device 12 attracts the plunger 16 is constant even if the power supply voltage fluctuates somewhat, and the responsiveness of the solenoid valve 10 is maintained.

The specific position of the annular groove 16a formed in the central portion of the plunger 16 is set so that the magnetic transfer portions of the yoke 15 and the plunger 16 and between the plunger 16 and the core 11 are not changed. In other words, the coil device 12 is set at a position where the force of attracting the plunger 16 does not decrease.

[0014]

The present invention has the following effects.

Due to the existence of the annular groove, the cross-sectional area of the magnetic path is partially narrowed, the amount of magnetic flux passing through the inside of the annular groove is limited, and the amount of magnetic flux passing through the plunger is reduced even if the power supply voltage fluctuates. Can be kept constant.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a solenoid valve according to an embodiment of the present invention.

[Explanation of symbols]

 10 Solenoid Valve 11 Core 12 Coil Device 13 Connector 14 Terminal 15 Yoke 16 Plunger 16a Annular Groove 17 Spring 18 Ball Stroke Valve 19 Shaft 21 Passage 22 Passage 23 Passage

Claims (1)

[Claims] 1. A plunger mounted in an axial hole of a yoke arranged in an inner peripheral portion of a coil device is axially displaced by excitation of the coil device, and a valve which moves integrally with the plunger is a passage. In the solenoid valve for opening and closing, the solenoid valve is characterized in that an annular groove is formed in the outer peripheral portion of the center of the plunger.