JPH05164263A - Solenoid valve - Google Patents

Abstract

PURPOSE:To increase the area of a plunger faced to a core and an attracting force for the plunger without increasing the weight thereof by forming a ring type recess section coaxially around a valve in the radial direction of the plunger, and adding a core in such a way as faced to the inside of the recess section. CONSTITUTION:A solenoid valve has a bobbin 2 housed in a casing 1 and a coil 3 is wound about the bobbin 2. Also, a core 4 is laid inside the bobbin 3 and a plunger 8 with a valve 6 fixed to the center thereof is attracted to the core 4 due to an electromagnetic force. Namely, when current is made to flow across the coil 3, the plunger 8 is attracted to the core 4 and the valve 6 is made to part from a valve seat 5, thereby selecting flow passages. In this case, a coaxial ring type recess section 8a is formed around the valve 6 in an axial direction, and an additional core 16 is so laid as to be faced to the inside of the recess section 8a. In addition, a part of an electromagnetic circuit is formed with the core 16, thereby increasing the area of the plunger 8 faced to the core 4 without increasing the weight thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve for controlling the hydraulic pressure of a hydraulic circuit such as an automatic transmission of an automobile.

[0002]

2. Description of the Related Art FIG. 3 shows, for example, Japanese Utility Model Laid-Open No. 63-142485.
FIG. 7 is a cross-sectional view showing a conventional solenoid valve of this type disclosed in Japanese Patent Publication No. In FIG. 3, reference numeral 1 denotes a case, 2 denotes a bobbin which is housed in the case 1 and around which a coil 3 is wound, 4 denotes a core fixed by caulking at a case end, and 5 denotes a valve seat forming a flow path. , 6 is a valve that opens and closes the flow path of the valve seat 5, 7 is a bearing that guides sliding of the valve 6, and 8
Is a plunger into which the valve 6 is press-fitted, and 9 is a return spring that biases the plunger 8 and the valve 6 toward the valve seat 5.

Next, the operation will be described. By passing a current through the coil 3, an electromagnetic force is generated around the coil 3, and the plunger 8 overcomes the biasing force of the spring 9 and is attracted to the core core 4 side. When the plunger 8 is sucked toward the core 4, the valve seat 5 and the valve 6 are separated from each other, and the flow path is opened. Then, when the electric current is cut off, the electromagnetic force disappears, and the plunger 8 is pressed against the valve seat 5 side by the urging force of the spring 9, so that the valve seat 5 and the valve 6
Closely adhere to each other and block the flow path. As described above, the current O
The plunger 6 is operated by N and OFF to control the opening and closing of the flow path.

[0004]

Since the conventional solenoid valve is constructed as described above, in order to increase the force for operating the plunger at the same current value, that is, the attraction force, the surface of the plunger facing the core is to be increased. Needs to be increased. However, if the outer diameter of the plunger is increased, the weight of the plunger increases, the operating noise increases, and the
There was a problem that the operation time at the time of OFF becomes long.

The present invention has been made to solve the above problems, and an object thereof is to provide a solenoid valve which operates with a small current without increasing the weight of the plunger.

[0006]

The solenoid valve according to the present invention has a ring-shaped recess coaxial with the plunger in the axial direction, and an additional core facing the inside of the recess.

[0007]

In the solenoid valve according to the present invention, since the recess is formed in the plunger and the core is opposed to the recess, the plunger surface facing the core can be enlarged without increasing the weight of the plunger. , The suction force can be increased with the same current value.

[0008]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a case, which is a first case 1a.
And the upper and lower parts of the second case 1b are divided into two. 2 is a bobbin which is housed in the first case 1a and around which a coil 3 is wound, 4 is a core fixed to the end of the first case 1a, and 5 is a housing which is housed in the second case 1b. A valve seat forming a passage, 6 is a valve for switching the flow passage formed in the valve seat 5, and 7 is a bearing fixed in the second case 1b for slidingly guiding the valve 6 on its inner surface. 8
Is a plunger which is press-fitted around the valve 6, and a ring-shaped concave portion 8a coaxial with the axial direction is formed in the lower portion of the plunger 8.
Are formed. Reference numeral 9 is a return spring that urges the plunger 8 and the valve seat 5 side, and 10 is provided between the plunger 8 and the return spring 9 and is used when the valve 6 moves from the ON state to the OFF state.
Spacers made of a non-magnetic material so that the plunger end surface 8b of the core can be quickly separated from the facing surface 4b of the core 4.
1 is a holder that abuts the inner surface of the first case 1a to form a magnetic circuit, 12 is a leaf spring that urges the holder 11 and the bobbin 2 toward the core 4 side so that the bobbin 2 does not rattle, and 13 is together with the first case 1a. A flange fixed to the second case 1b by caulking, 14 is a ball that contacts the tip 6a of the valve 6 to switch the flow path, and 15 is a ball 14 that urges the ball 14 toward the valve seat 5 and causes the return spring 9 to move. A weak spring having a considerably weaker biasing force, 16 is the recess 8
It is an additional core that faces the inside of a and is fixed to the second case side to form a part of a magnetic circuit.

Next, the operation will be described. As shown in FIG. 1, when the valve 6 is not moving, that is, when the current is not flowing through the coil 3, the valve 6 is in contact with and closely attached to the valve seat 5. Next, when a current is applied to the coil 3, the plunger 8 moves to the core 4 as shown in FIG.
Is sucked to the side, the valve 6 separates from the valve seat 5, and the flow path is switched. Therefore, at this time, a concave portion 8a is formed in the plunger 8 so that the additional core 16 faces the inside of the concave portion.
Since this additional core forms part of the magnetic circuit, the surface of the plunger facing the core can be enlarged without increasing the weight of the plunger, and the force that operates the plunger at the same current value, that is, suction The force can be increased and the operating noise of the valve can be reduced because the weight of the movable part of the plunger 8 is not heavy.

[0010]

As described above, according to the present invention, the operating current and the operating noise can be reduced with a simple structure in which the movable plunger is provided with the concave portion and the additional core is arranged so as to face the concave portion.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, in which the valve O
It is sectional drawing of a FF state.

FIG. 2 shows an embodiment of the present invention, in which the valve O
It is sectional drawing of N state.

FIG. 3 is a cross-sectional view showing a conventional solenoid valve.

[Explanation of symbols]

 1 case 2 bobbin 3 coil 4 core 8 plunger 8a recess 16 additional core

Claims (1)

[Claims] 1. A case, a bobbin provided in the case and wound with a coil, a core provided inside the bobbin, and an electromagnetic force attracted to the core to fix a valve at the center. A solenoid valve comprising the above-mentioned plunger, wherein a ring-shaped recess is formed coaxially around the valve in the axial direction of the plunger, and an additional core is provided so as to face the inside of the recess.