JPH04285380A - Solenoid valve - Google Patents

Abstract

PURPOSE:To improve the high-speed responsiveness at the time of switching operation, prevent the burning of a coil winding, and improve the durability in a solenoid valve. CONSTITUTION:An electromagnetic coil 5 for driving a valve has a first coil winding 5a and second coil winding 5b in which the directions of the electromagnetic attracting forces are identical. When a reciprocal needle 12 is driven against a compression coil spring 16 by the electromagnetic attracting force, the first coil winding 5a and second coil winding 5b are electrified at the time of the valve initial operation requiring a large driving force. During the valve holding period for which a small driving force suffcies after the end of the valve initial operation, the electrification of the coil winding 5a is stopped and the electrification of the second coil winding 5b is continued.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly responsive solenoid valve that opens and closes at high speed.

0002

[Prior Art] Conventionally, the current control circuit for a solenoid valve is expensive and the control driver is large. A circuit is known (Japanese Patent Publication No. 63-4068). Such conventional solenoid valves are
This controls the current supplied to the electromagnetic coil during the valve opening operation and during the valve opening holding period. The general structure of a solenoid valve is such that when electricity is applied, a coil is excited, and an electromagnet formed by this exciting coil moves a movable part against a return spring, thereby opening or closing the valve member. .

0003

[Problems to be Solved by the Invention] In recent years, there has been a demand for faster opening and closing operations of solenoid valves. In particular, high-speed response is required for electromagnetic valves applied to fuel supply systems for internal combustion engines. One possible way to improve the high-speed response of a solenoid valve is to increase the amount of current supplied by increasing the wire diameter of the coil winding and decreasing the coil resistance value. but,
If excessive current is supplied, the coil winding will easily burn out and the durability of the solenoid valve will deteriorate, so there is a certain limit to increasing the wire diameter of the coil winding in order to reduce the resistance value of the coil winding. . The present invention was made to solve these problems, and an object of the present invention is to provide a solenoid valve that prevents the coil winding from being burnt out, has good durability, and has excellent high-speed response.

0004

[Means for Solving the Problems] A solenoid valve according to the present invention for solving the above problems includes a valve member that can reciprocate, and a guide hole that guides the valve member in the axial direction, and the valve member can come into contact with the guide hole that guides the valve member in the axial direction. a valve body having a valve seat portion, a biasing device that biases the valve member in an opening direction or a closing direction, and a coil winding that drives the valve member by an electromagnetic attraction force against the biasing device. and includes a first coil winding and a second coil winding in which the direction of electromagnetic attractive force is the same as each other, and when the valve is initially operated, the first coil winding and the second coil winding are energized, and the valve is initially operated. The valve is characterized in that the energization to the first coil winding is stopped during the valve holding period after the end of the operation.

[0005]

[Operation] According to the solenoid valve of the present invention, if the valve is normally open, a temporary large current is supplied to the first coil winding and the second coil winding at the initial stage of the valve closing operation, thereby causing the valve member to Speeds up physical valve closing operation. Next, during the period when the valve member is held in the closed position, the supply of current to the first coil winding is stopped, but at this time, the supply of current to the second coil winding is continued.
The closed state of the valve member is maintained. Thereafter, at the end of the valve closing, that is, at the time of the valve opening operation, the supply of current to the second coil winding is stopped. As a result, when a large current is required at the beginning of the valve closing operation, current is applied to the first coil winding and the second coil winding to speed up the valve closing operation, and during the subsequent valve closing period, the valve holding force is increased. Since a driving force smaller than the valve operating force is sufficient, a low current is sufficient, and the valve is maintained in the closed state by supplying current only to the second coil winding. Therefore, the amount of current supplied can be saved, and burnout of the coil winding can be prevented, thereby extending the life of the coil.

[0006]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. FIG. 1 shows an embodiment of a solenoid valve provided in a fuel passage supplying an internal combustion engine. This solenoid valve is of a type that moves from an open position to a closed position when electric current is supplied. Inside the cylindrical housing 2 of the electromagnetic valve 1, a bobbin 4 holding a coil winding 5 is fixed to a holding member 3. The disc-shaped cover 6 that fixes this holding member 3 is
It is caulked and fixed to the end of the housing 2 via an O-ring 7. The connector 8 fixed to the top of the cover 6 is
Terminal 21 for holding the lead wire from the coil winding 5
, 22, 23.

A valve body 11 fixed to the housing 2 has a needle 12 slidably guided in the axial direction by the inner circumferential wall of a guide hole opened in the center of the valve body 11 . One end of the sliding portion 12a of the needle 12 is connected to a small diameter portion 12b, and a large diameter valve portion 12c is formed at the end of this small diameter portion 12b. The valve portion 12c can come into contact with a valve seat portion 11b formed on the valve body 11. The needle 12 shown in FIG. 1 is shown in a state in which it is in contact with the valve seat portion 11b. A fuel passage 11a communicating with the valve seat portion 11b is opened in the valve body 11. A disk-shaped stopper 14 having a fuel passage 11a is provided on the end face 11c of the valve body 11, and an annular casket 13 having a fuel passage 13a is attached to the end face of the stopper. One end 16a of the compression coil spring 16 is attached to the opposite end 12d of the needle 12.
The other end 16b is in contact with a protrusion 6a made of a fixed iron core protruding from the center of the cover 6. In addition,
Three terminals 21, 22, and 23 are taken out from the connector 8 to be connected to the coil 5, which will be described later.

Next, the structure of the coil winding 5 will be explained. As shown in FIG. 3, the coil winding 5 consists of a first coil winding 5a and a second coil winding 5b. The wire diameter of the second coil winding 5b is larger than that of the second coil winding 5b, and they are wound in the same direction. The terminals of the first coil winding 5a and the second coil winding 5b are connected to each other by a terminal 26 at one terminal of each coil winding. Then, three terminals labeled ■, ■, and ■ are taken out. A schematic diagram of the electric circuit of this solenoid valve 1 is shown in FIG. The first coil winding 5a and the second coil winding 5b are connected in parallel between terminals 25 and 26, which are respectively connected to the positive and negative poles of the power source 24 by lead wires. 27, 2
8 are the first coil winding 5a and the second coil winding 5, respectively.
This is a transistor switch that turns on and off b.

Next, the operation of the solenoid valve 1 will be explained based on FIG. 1. First, the first coil winding 5a and the second
When the coil winding 5b is energized, each coil winding 5a, 5
A magnetic circuit is formed in the holding member 3 and the housing 2 by the excitation of b, and the needle 12 is moved by the compression coil spring 16 due to the attraction action generated in the magnetic gap at the tip of the holding member 3.
lift upward in FIG. Then, needle 1
The second valve portion 12c contacts the valve seat portion 11b and closes. Thereafter, even if the first coil winding 5a is de-energized, the needle 12 remains closed as long as the second coil winding 5b is energized. Next, when the power supply to the second coil winding 5b is stopped, the needle 12 is pushed down in FIG.
The valve portion 12c of the needle 12 is separated from 1b. This opens the valve. When the valve is open, fuel flows through the fuel passages 13a, 1
4b, and flows out from the fuel passage 11a through the periphery of the small diameter portion 12b.

The state of energization of the coil winding 5 during the opening/closing operation of the solenoid valve 1 will be described in more detail with reference to FIG. During the initial valve closing operation, the currents i, i flowing through the electric circuit shown in Fig. 2
1 and i2 have characteristics as shown in FIG. At the start of the initial valve closing operation (t=0), currents i1 and i2 are supplied to the first coil winding 5a and the second coil winding 5b, respectively, and the current level rises. The rise of the current i becomes a relatively large current due to the supply of current to the two types of coil windings 5a and 5b. Therefore, the initial movement of the needle 12 lifting upward in FIG. 1 against the compression coil spring 16 is fast. That is, the valve changes quickly from the open state to the closed state. Thereafter, the transition operation from the valve open position to the valve close position is completed during the initial valve closing operation time t1. time t1
After elapse of , the supply of current i1 to the first coil winding 5a is stopped. The supply of current i2 to the second coil winding 5b continues as it is. After time t1 passes, time t2
The valve remains closed until the time period elapses. During this valve-closed holding period (between t1 and t2), the current supplied to the coil winding 5 is only the current to the second coil winding 5b, so the valve is kept closed and the amount of current supplied savings will be achieved. Thereafter, after time t2 has elapsed, the supply of current i2 to the second coil winding 5b is also stopped. Then, the valve is quickly switched from the closed state to the open state.

Since the current is controlled as described above, from the start of the initial valve closing operation (t=0) to the end of the initial operation (t=t
During 1), the amount of current supplied to the coil is relatively large, but the current supply time is short, so burning out of the coil winding 5 is prevented. Further, by supplying the large current i at the initial stage, the valve is quickly moved from the open position to the closed position. In other words, responsiveness is improved. Furthermore, after the elapse of time t1 until time t2, the amount of current supplied is only current i2, but the needle 12
After the lift, a small amount of holding current is sufficient due to the reduced air gap, so the closed state is maintained with a small amount of supplied current. Then, after time t2 has elapsed, the valve returns from the closed state to the open position. At this time, from current i2, current i=
Since the change in the amount of current supplied to 0 is small, the valve movement speed from the time of closing to the time of valve opening is fast and responsiveness is good, and the valve is moved at high speed.

In the above embodiment, two types of coil windings, the first coil winding 5a and the second coil winding 5b, are used.
Although the wire diameter of the coil winding 5a is made larger than the wire diameter of the second coil winding 5b, it goes without saying that coil windings of the same diameter may be used, and three or more types of coil windings may be used. established,
The current may be controlled in stages when the valve is operated. Further, although the solenoid valve used in the above embodiment is a normally open valve, it may be applied to a normally closed valve, and furthermore, any type of solenoid valve can be used, such as an inward-opening type or an outward-opening type.

[0013]

Effects of the Invention As explained above, according to the solenoid valve of the present invention, two or more types of coil windings are used to create electromagnetic attraction force, and the electromagnetic attraction force can be increased as much as at the start of valve movement. When driving force is required, a large current is supplied to two or more types of coil windings, and when the valve is in the holding state, the amount of current supplied to the coil windings is reduced, resulting in faster valve opening/closing and faster response. This has the effect of not only improving the durability of the electromagnetic valve but also preventing burnout of the coil winding and increasing the durability of the solenoid valve.

[Brief explanation of the drawing]

FIG. 1(A) is a plan view showing a connector portion of a solenoid valve according to an embodiment of the present invention. (B) is a sectional view showing the solenoid valve.

FIG. 2 is a schematic diagram showing an electrical circuit according to an embodiment of the invention.

FIG. 3 is a schematic diagram showing a connection state of coil windings according to an embodiment of the present invention.

FIG. 4 is a characteristic diagram showing the amount of current supplied to each coil winding of the electromagnetic valve according to the embodiment of the present invention.

[Explanation of symbols] 1 Solenoid valve 5 Coil winding 5a First coil winding 5b Second coil winding 11 Valve body 11b Valve seat part 11d Guide hole 12 Needle (valve member)

Claims (1)

[Claims] 1. A valve body having a reciprocating valve member, a guide hole that guides the valve member in the axial direction, and a valve seat portion that the valve member can abut, and a valve member that is movable in the opening direction or in the opening direction. a first coil winding that drives the valve member by an electromagnetic attraction force against the biasing means, the directions of the electromagnetic attraction forces being the same; and a second coil winding, the first coil winding and the second coil winding are energized during the initial valve operation, and the first coil winding is energized during the valve holding period after the end of the valve initial operation. A solenoid valve characterized by stopping.