JP2000130128A - Solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise and abrasion by reducing impact in seating of a valve element. SOLUTION: A valve 21 for opening and closing a port 3 is attached to a cylinder head 1, an electromagnetic driving device 5 composed of a moving disc 7 for driving the valve 21, energizing springs 8 and 9, and first and second electromagnetic coils 10 and 11 is attached, and a driving circuit 26 and a control circuit 27 are connected to the electromagnetic coils 10, 11. A valve element position detecting device 22 composed of a magnet 25 attached on the tip side of a valve stem 21B and a hall element 24A is attached on the electromagnetic driving device 5. The control circuit 27 outputs a pulse-like impact alleviating signal to the second electromagnetic coil 11 just before a valve element 21A of the valve 21 is seated on a valve seat 3A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetically driven valve which is opened and closed by an electromagnetic force, and more particularly to an electromagnetically driven valve suitable for use as an intake / exhaust valve of an internal combustion engine driven by an electromagnetic drive.

[0002]

2. Description of the Related Art An electromagnetically driven valve for electromagnetically driving an intake / exhaust valve of an internal combustion engine in order to easily change a valve timing has been known (for example, Japanese Patent Laid-Open No. 7-33).
2044, JP-A-7-83012, etc.).

Here, such a conventional electromagnetically driven valve will be described with reference to FIGS. 6 and 8. FIG.

In FIG. 1, reference numeral 1 denotes a cylinder head serving as a valve seat member provided on a cylinder (both not shown) of an engine body, and a piston ( A combustion chamber 2 is defined between the cylinder head 1 and the cylinder head 1, and an intake port having a valve seat 3 </ b> A communicating with the combustion chamber 2 and a port 3 serving as a discharge port are formed in the cylinder head 1. . The opening side of the port 3 serves as a valve seat 3A of a valve body 4A, which will be described later. The valve 3A is seated and separated from the valve seat 3A, so that the port 3 is closed and opened.

Reference numeral 4 denotes a valve which opens and closes the port 3 of the cylinder head 1 so as to be separated from and seated on the valve seat 3A. The valve 4 is a disc-shaped valve which comes into contact with and separates from the valve seat 3A. Body 4
A and a valve shaft 4B fixed to the valve body 4A and extending from the combustion chamber 2 toward the upper side of the cylinder head 1. The valve shaft 4B extends into an electromagnetic drive device 5 described later.

Reference numeral 5 denotes an electromagnetic drive device 5 as a drive device mounted on the cylinder head 1. The electromagnetic drive device 5 includes a casing 6, a moving disk 7, biasing springs 8, 9, electromagnetic coils 10, 11, and the like. It is composed of

Reference numeral 6 denotes a casing which forms the outer shape of the electromagnetic drive device 5. The casing 6 is formed in a cylindrical shape extending upward from the cylinder head 1. A coil 10 is provided, and an urging spring 9 and an electromagnetic coil 11 are provided on the upper side in the axial direction.

Reference numeral 7 denotes a moving disk serving as a moving element attached to the valve shaft 4 and connected to the valve body 4A. The moving disk 7 is formed of a magnetic material such as iron, and is formed in the casing 6 in the axial direction. It is arranged at the center and is displaceable in the axial direction within the casing 6. The moving disk 7 is always located in the axial center of the casing 6 by being sandwiched between the urging springs 8 and 9. Thereby, the valve 4
Is always located at a neutral position between a valve opening position where the valve element 4A is farthest from the valve seat 3A and a valve closing position where the valve element 4A is seated on the valve seat 3A.

The moving disk 7 includes electromagnetic coils 10, 1
1 and faces the electromagnetic coils 10 and 11. By supplying a current to the electromagnetic coils 10 and 11 from a drive circuit 13 described later, the moving disk 7 is displaced in the axial direction toward the electromagnetic coils 10 and 11.

Reference numerals 8 and 9 denote urging springs for urging the moving disk 7 toward the axial center of the casing 6, and the lower end of the urging spring 8 positioned axially below the casing 6 has a lower end. The upper end is in contact with the bottom surface of the moving disk 7 while being in contact with the bottom surface. Further, the biasing spring 9 located on the upper side in the axial direction in the casing 6 has its lower end side abutting on the surface side of the moving disk 7 and the upper end side of the biasing spring 9 is provided on the adjusting screw 12 provided on the axially upper end side of the casing 6. Abut.

Reference numeral 10 denotes a first electromagnetic coil which attracts the moving disk 7 by electromagnetic attraction and drives the valve body 4A.
The electromagnetic coil 10 is disposed below the casing 6 in the axial direction. And the electromagnetic coil 10 is
The moving disk 7 is interposed between the moving disk 7 and the clearance L1.
Are separated by an interval of. The electromagnetic coil 10 includes a core part 10A and a coil part 10B.
A is formed in an annular shape having a U-shaped cross section by a magnetic material such as iron, and the coil portion 10B is formed by winding a copper wire or the like and disposed in a groove of the core portion 10A.

A current is supplied to the electromagnetic coil 10 from a drive circuit 13 to be described later, so that the electromagnetic coil 1
0 attracts the moving disk 7 toward the electromagnetic coil 10 side.
As a result, the valve shaft 4B and the casing 6
, And the valve body 4A moves to the valve opening position.

Reference numeral 11 denotes a second electromagnetic coil which attracts the moving disk 7 by electromagnetic attraction and drives the valve element 4A.
The electromagnetic coil 11 is disposed axially inside the casing 6. The electromagnetic coil 11 faces the moving disk 7 and is spaced apart from the electromagnetic coil 10 with an interval of a gap L2.
In addition, the electromagnetic coil 11 is a core 10 of the electromagnetic coil 10.
A, comprises a core portion 11A and a coil portion 11B substantially similar to the coil portion 10B.

A current is supplied to the electromagnetic coil 11 from a drive circuit 13 to be described later, so that the electromagnetic coil 1
1 attracts the moving disk 7 toward the electromagnetic coil 11 side.
As a result, the valve shaft 4B and the casing 6
, And the valve body 4A moves to the valve closing position.

An adjusting screw 12 is screwed to the upper end of the casing 6 in the axial direction. The adjusting screw 12 is in contact with the biasing spring 9. Then, by displacing the adjusting screw 12 in the axial direction, the moving disk 7 is displaced in the axial direction. Thus, the adjusting screw 12 adjusts the neutral position of the valve body 4A.

Reference numeral 13 denotes a drive circuit which constitutes valve body position control means together with the control circuit 14. The drive circuit 13 is connected to the control circuit 14. The drive circuit 13 outputs the valve opening signal Sa from the control circuit 14 to the electromagnetic coil 10 and outputs the valve closing signal Sb to the electromagnetic coil 11 to supply current to the electromagnetic coils 10 and 11.

The electromagnetically driven valve according to the prior art has the above-described configuration, and its operation will be described below.

First, when opening the port 3, the control circuit 14 outputs a valve opening signal Sa to the electromagnetic coil 10 through the drive circuit 13. Thereby, the electromagnetic coil 10
Current ia (not shown) flows through the electromagnetic coil 1
0 attracts the moving disk 7, and the valve body 4A moves to the valve opening position. When the valve body 4A moves to the valve opening position, the control circuit 14 outputs a pulse-shaped valve opening signal Sa to hold the valve body 4A at the valve opening position. Thereby, the valve element 4
A stops at the valve open position. When the control circuit 14 stops outputting the valve opening signal Sa, the valve element 4A returns to the neutral position.

On the other hand, when closing the port 3, the control circuit 14 outputs a valve closing signal Sb to the electromagnetic coil 11 through the drive circuit 13 as shown by a characteristic line a in FIG. At this time, since a current ib flows through the electromagnetic coil 11 as shown by a characteristic line b in FIG. 7, the electromagnetic coil 11 generates an electromagnetic attraction by the current ib. Then, the moving disk 7 is attracted by the electromagnetic coil 11 and is displaced toward the electromagnetic coil 11 against the spring force of the biasing spring 9. Thereby, the valve shaft 4B of the valve 4 is displaced axially upward together with the moving disk 7, and the valve body 4A moves to the valve closing position.

When the valve body 4A reaches the valve closing position,
The control circuit 14 controls the valve body 4A to maintain the seated state.
A pulse-shaped valve closing signal Sb is output to the electromagnetic coil 11 through the drive circuit 13. As a result, although the current ib flowing through the electromagnetic coil 11 is reduced, the moving disk 7 does not separate from the electromagnetic coil 11 because the gap dimension L2 is sufficiently small, and the valve body 4A is seated on the valve seat 3A. Stop at When the control circuit 14 stops outputting the valve closing signal Sb, the valve element 4A returns to the neutral position.

[0021]

However, in the electromagnetically driven valve according to the prior art, the moving disk 7 disposed at a position separated from the electromagnetic coils 10 and 11 is moved by the electromagnetic coils 10 and 11.
In order to displace toward the side 11, the electromagnetic coils 10,
It is necessary that the electromagnetic attraction by the spring 11 is larger than the spring force Fs generated by the biasing springs 8 and 9.

Here, the electromagnetic attraction Fa, Fb generated for attracting the moving disk 7 when a current is supplied to the electromagnetic coils 10, 11 is determined by the electromagnetic coils 10, 11 as shown by solid lines in FIG. Is a non-linear function with respect to the gap dimensions L1 and L2 formed between the moving disk 7 and the gaps L1 and L2.
It has the characteristic that the force increases rapidly as L2 decreases.

On the other hand, the biasing springs 8 and 9 are elastic members that generate a spring force Fs proportional to the displacement length using a constant spring constant as a proportional constant. For this reason, the spring force Fs of the biasing springs 8 and 9 is reduced as shown by the dotted line in FIG.
A force proportional to the displacement length of the biasing springs 8, 9 is generated irrespective of the gap dimensions L1, L2 between the moving discs 0, 11 and the moving disc 7.

For example, when a constant current is supplied to the electromagnetic coil 11 to close the port 3 and the movable disk 7 is displaced axially upward against the spring force Fs, the valve element 4A As the position approaches the valve closing position, the gap dimension L2 decreases. At this time, as the gap L2 becomes smaller, the moving disk 7 is strongly attracted to the electromagnetic coil 11 side, and the moving disk 7 moves while accelerating. For this reason, there is a problem that the valve body 4A strongly collides with the valve seat 3A, generating a loud noise, an excessive load is applied to the valve body 4A and the valve seat 3A, and wear of the valve seat 3A and the like increases.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention provides an electromagnetically driven valve capable of reducing noise and wear by reducing the impact when the valve body is seated. It is intended to provide.

[0026]

According to the present invention, there is provided a valve seat member having a port formed with a valve seat.
A valve body which is detachably seated on the valve seat to open and close the port of the valve seat member, and a driving device provided on the valve seat member for driving the valve body between a valve opening position and a valve closing position. A moving element provided in connection with the valve element, and urging the valve element toward a neutral position between the valve opening position and the valve closing position via the moving element. A biasing spring, a first electromagnetic coil that attracts the mover in one direction against the biasing spring and drives the valve body toward a valve-opening position, and the movement against the biasing spring. A second electromagnetic coil that drives the valve body toward the valve closing position by sucking the child in another direction, and a valve closing signal that is output to the first electromagnetic coil when the valve body is opened. When the valve is closed, a valve closing signal is output to the first electromagnetic coil to control the position of the valve body. It is applied to the lube.

A feature of the structure adopted by the first aspect of the present invention is that the drive unit is provided with a valve body position detecting means for detecting the position of the valve body, and the valve body position control means is provided with the valve body. Using the detection signal from the position detection means, the valve closing signal amount supplied to the second electromagnetic coil is reduced between just before the valve body is seated and before the valve body is seated, and the valve body is opened by the second electromagnetic coil. This is to reduce the impact when sitting on the seat.

With this configuration, the valve body position detecting means can detect which position the valve body is between the valve opening position and the valve closing position. The valve element position control means can determine whether or not the valve element has reached a position immediately before the valve element is seated by using a detection signal from the valve element position detection means, and from just before the valve element is seated. Before the seat is seated, the valve closing signal amount supplied to the second electromagnetic coil is reduced. This allows
The impact when the valve body is seated on the valve seat by the second electromagnetic coil can be reduced.

According to a second aspect of the present invention, the valve body position detecting means includes a magnet connected to the valve body and a magnetic sensor fixed near the magnet and detecting a magnetic flux density by the magnet. It has been configured.

Thus, the magnet moves together with the valve body, so that the distance between the magnet and the magnetic sensor changes according to the position of the valve body. When the magnet approaches the magnetic sensor, the magnetic flux density increases around the magnetic sensor, and when the magnet separates from the magnetic sensor, the magnetic flux density decreases around the magnetic sensor. As described above, since the magnetic flux density of the magnet changes around the magnetic sensor according to the position of the valve body, the position of the valve body can be detected by the magnetic sensor.

According to a third aspect of the present invention, the valve closing signal output from the valve body position control means is a pulse-shaped valve closing start signal output between the neutral position and immediately before the valve is seated. A pulse-like shock mitigation signal that is output just before the valve element is seated until it is seated and has a smaller duty ratio than the valve-closing start signal, and a pulse-like shock mitigation signal that is output when the valve element is held in a seated state. It is constituted by a pulse-like holding signal having a smaller duty ratio than the relaxation signal.

With this configuration, the valve body position control means sends the pulse-shaped valve-closing start signal having the largest duty ratio to the second electromagnetic coil from the neutral position to just before the valve body is seated. Output. Thus, a large valve closing signal amount can be supplied to the second electromagnetic coil, and the valve body moves toward the valve closing position against the biasing spring.

The valve body position control means outputs a pulse-like impact mitigation signal to the second electromagnetic coil during a period from immediately before the valve body is seated to when it is seated. At this time, the duty ratio of the shock mitigation signal is set to a value smaller than the duty ratio of the valve closing start signal. For this reason, the valve closing signal amount supplied to the second electromagnetic coil is smaller than when the valve closing start signal is being output, and the speed at which the valve element moves toward the valve closing position decreases.

Further, the valve body position control means outputs a pulse-like holding signal having a smaller duty ratio than the shock mitigation signal to the second electromagnetic coil when the state in which the valve body is seated is maintained. As a result, the valve closing signal amount supplied to the second electromagnetic coil is further reduced as compared with when the impact mitigation signal is output, but the valve body stops at the valve closing position against the biasing spring. I do.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electromagnetically driven valve according to the present invention will be described below in detail with reference to FIGS. In the present embodiment, the same components as those in the related art are denoted by the same reference numerals, and description thereof will be omitted.

In the figure, reference numeral 21 denotes a valve for opening and closing the port 3. The valve 21 is substantially the same as the valve 4A and the valve shaft 4B of the valve 4 according to the prior art.
However, this is different from the prior art in that the valve shaft 21B extends through the electromagnetic driving device 5 in the axial direction and extends into the valve body position detecting device 22 described later.

The moving disk 7 is mounted in the middle of the valve shaft 21B located in the electromagnetic drive device 5, and a magnet 25 to be described later is fixed to the distal end of the valve shaft 21B.

Numeral 22 designates a valve element position detecting device as a valve element position detecting means attached to the electromagnetic drive device 5. The valve element position detecting device 22 comprises an auxiliary casing 23, a hall element 24,
It is composed of a magnet 25.

Reference numeral 23 denotes an auxiliary casing which forms the outer shape of the valve body position detecting device 22. The auxiliary casing 23 is formed of, for example, a resin material into a substantially cylindrical shape, and is located on the casing 6 of the electromagnetic drive device 5 and is provided with screws or the like. It is provided so that it can be attached and detached. And the auxiliary casing 23
Inside, a Hall element 24 and a magnet 25 are provided.

Reference numeral 24 denotes a Hall element as a magnetic sensor provided in the auxiliary casing 23.
Is located on the upper end side of the auxiliary casing 23 and faces a magnet 25 described later with a gap. Then, the Hall element 24 detects the density of the magnetic flux Φ by the magnet 25 and outputs the detection signal Sp using the output signal V from the Hall element 24 only during a period from immediately before the valve element 21A is seated to when it is seated. A processing circuit 24A is additionally provided.

The Hall element 24 includes a magnet 25
Also, they are arranged on the same axis line O-O of the valve shaft 21B. The Hall element 24 detects a magnetic flux density in a direction parallel to the direction in which the magnet 25 is magnetized, and outputs an output signal V corresponding to the magnetic flux density.

Reference numeral 25 denotes a magnet provided on the tip end side of the valve shaft 21B. The magnet 25 faces the Hall element 24 with a gap in the axial direction of the valve shaft 21B. The magnet 25 is magnetized in the radial direction of the valve shaft 21B as shown in FIG. 2, and has magnetic poles (N-pole, S-pole) formed at both ends in the radial direction. Then, the magnet 25 comes closest to the Hall element 24 when the valve body 21A moves to the valve closing position as shown in FIG. 3, and when the valve body 21B moves to the valve opening position as shown in FIG. It is the one farthest from the Hall element 24.

Reference numeral 26 denotes a drive circuit which constitutes valve body position control means together with the control circuit 27. The drive circuit 26 is connected to the control circuit 27 as shown in FIG. Then, the drive circuit 26 outputs a valve opening signal Sa composed of a pulsed voltage signal from the control circuit 27 to the electromagnetic coil 10, and outputs a valve closing signal Sb composed of a pulsed voltage signal to the electromagnetic coil 11, A current is supplied to the electromagnetic coils 10 and 11.

Further, a Hall element 24 is connected to the control circuit 27, and a detection signal Sp from the Hall element 24 is inputted. When the control circuit 27 closes the port 3 using the detection signal Sp, the control circuit 27
As shown in FIG. 5, a valve closing signal Sb including a valve closing start signal Sb1, an impact mitigation signal Sb2, and a holding signal Sb3 is output to the second electromagnetic coil 11 in accordance with the position of the valve element 21A. is there. The valve closing start signal Sb1, the shock mitigation signal Sb2, and the holding signal Sb3 have their peak values set to substantially equal values, but have different duty ratios. Therefore, the current ib 'as the valve closing signal amount supplied to the electromagnetic coil 11 changes according to the duty ratio of the valve closing start signal Sb1, the shock mitigation signal Sb2, and the holding signal Sb3.

The electromagnetically driven valve according to the present embodiment has the above-described configuration, and its operation will now be described.

First, when opening the port 3, the control circuit 27 outputs a valve opening signal Sa to the electromagnetic coil 10 through the drive circuit 26, which is almost the same as in the prior art. As a result, a current flows through the electromagnetic coil 10, so that the electromagnetic coil 10 attracts the moving disk 7, and the valve body 21A moves to the valve opening position. When the valve body 21A moves to the valve opening position, the control circuit 27 outputs a pulse-shaped valve opening signal Sa to hold the valve body 21A at the valve opening position. Thereby, the valve body 21A stops at the valve opening position. And
When the control circuit 27 stops outputting the valve opening signal Sa, the valve element 21A returns to the neutral position.

On the other hand, when closing the port 3, the control circuit 27 sends a valve closing start signal Sb1 consisting of a pulsed voltage to the electromagnetic coil 11 through the drive circuit 26 as shown by the characteristic line c in FIG. Output. Here, the duty ratio of the valve closing start signal Sb1 is set to, for example, about 100%. At this time, the current ib 'as the valve closing signal amount flows through the electromagnetic coil 11 in accordance with the duty ratio of the valve closing start signal Sb1 as shown by the characteristic line d in FIG. 11 generates an electromagnetic attractive force by the current ib '. The moving disk 7 is the electromagnetic coil 1
1 and is displaced toward the electromagnetic coil 11 against the spring force of the biasing spring 9. Thereby, the valve shaft 2 of the valve 21
1B is displaced axially upward together with the moving disk 7 and
A moves to the valve closing position.

At this time, as the valve body 21A approaches the valve closing position, the magnet 25 and the Hall element 24 approach each other, so that the magnetic flux Φ around the Hall element 24 as shown in FIG.
And the magnetic flux density increases. Therefore, the output signal V such as the voltage by the Hall element 24 increases as the valve body 21A approaches the valve closing position as shown by the characteristic line f in FIG.

Next, as shown in FIG. 3, when the valve body 21A comes closer to the valve seat 3A than the predetermined clearance dimension δ, the output signal V from the Hall element 24 is changed to the predetermined first determination value. It becomes larger than V1. At this time, the processing circuit 24A determines that the valve body 21A is on the verge of sitting on the valve seat 3A, and detects the detection signal S as shown by a characteristic line e in FIG.
Start the output of p.

Thus, the control circuit 27 uses the detection signal Sp from the Hall element 24 to determine that the valve body 21A is on the verge of being seated, and as shown by the characteristic line c in FIG. During the period from just before the seating to the seating, the impact relaxation signal Sb2 composed of a pulsed voltage is output to the electromagnetic coil 11.

At this time, the duty ratio of the shock mitigation signal Sb2 is set to a value smaller than the duty ratio of the valve closing start signal Sb1, for example, about 80%. This allows
Current ib 'as a valve closing signal amount flowing through the electromagnetic coil 11
And the electromagnetic attraction by the electromagnetic coil 11 decreases.
Therefore, the speed when the valve body 21A is seated on the valve seat 3A is reduced, and the impact when the valve body 21A is seated on the valve seat 3A is reduced.

Next, when the valve body 21A reaches the valve closing position and the valve seat 3A is seated, the output signal V from the Hall element 24 becomes larger than the second predetermined judgment value V2. At this time, the processing circuit 24A determines that the valve body 21A has the valve seat 3
It is determined that the vehicle is sitting on A, and the output of the detection signal Sp is stopped as shown by the characteristic line e in FIG.

Thus, the control circuit 27 determines that the valve seat 3A is seated using the detection signal Sp from the Hall element 24, and as shown by the characteristic line c in FIG.
A holding signal Sb3 composed of a pulsed voltage is output to the electromagnetic coil 11 through the drive circuit 26 in order to maintain the seating state of the electromagnetic coil 11.

At this time, the duty ratio of the holding signal Sb3 is set to a value smaller than the duty ratio of the shock mitigation signal Sb2, for example, about 30%. As a result, although the current ib 'flowing through the electromagnetic coil 11 further decreases, the moving disk 7 does not separate from the electromagnetic coil 11, and the valve body 21A stops while seated on the valve seat 3A.
Then, when the control circuit 27 stops outputting the holding signal Sb3, the valve body 21A returns to the neutral position.

As described above, when the control circuit 27 outputs the valve closing start signal Sb1 and the shock mitigation signal Sb2, the valve body 21A performs the valve closing operation, and the control circuit 27 outputs the holding signal Sb3.
Is output, the valve element 21A performs a holding operation.

Thus, according to the present embodiment, the valve position detecting device 22 for detecting the position of the valve 21A is attached to the electromagnetic drive device 5, and the control circuit 27 detects the position by the valve position detecting device 22. The valve 21A is moved to the valve seat 3 using the signal Sp.
The current ib 'flowing through the second electromagnetic coil 11 between the time immediately before the user sits on A and the time when he / she sits on A is reduced.

As a result, the electromagnetic attraction of the second electromagnetic coil 11 can be reduced just before sitting on the valve seat 3A, and the valve body 21A is moved by the second electromagnetic coil 11 to the valve seat 3A.
The impact at the time of sitting on A can be reduced. Therefore, noise when the valve body 21A is seated can be reduced, and the life of the valve 21, the valve seat 3A and the like can be extended.

Further, the valve element position detecting device 22 is connected to the valve element 21.
A and the Hall element 24 fixedly provided in the vicinity of the magnet 25, the distance between the magnet 25 and the Hall element 24 depends on the position of the valve element 21A. Change. When the magnet 25 approaches the Hall element 24, the magnetic flux density increases around the Hall element 24, and when the magnet 25 separates from the Hall element 24, the magnetic flux density decreases around the Hall element 24. The valve body 21A
Moves to the valve closing position, the magnet 25 and the Hall element 24 come closest to each other, and when the valve body 21A moves to the valve opening position, the magnet 25 and the Hall element 24 move farthest from each other. As a result, the magnetic flux density from the magnet 25 increases and decreases around the Hall element 24 in accordance with the position of the valve element 21A.
The position of 1A can be detected.

The control circuit 27 outputs a valve closing signal Sb composed of a pulsed valve closing start signal Sb1, an impact mitigation signal Sb2, and a holding signal Sb3.
The valve closing start signal Sb1 having a large duty ratio is output to the second electromagnetic coil 11 during a period from 1A to a position immediately before the seating of 1A. As a result, a large current ib 'flows through the second electromagnetic coil 11, so that the valve body 21A can be quickly moved to the valve closing position.

The control circuit 27 outputs to the second electromagnetic coil 11 an impact mitigation signal Sb2 having a duty ratio smaller than the valve closing start signal Sb1 during a period from immediately before the valve body 21A is seated to when it is seated. . As a result, the current ib 'flowing through the second electromagnetic coil 11 decreases compared to when the valve closing start signal Sb1 is being output, and the speed at which the valve element 21A moves toward the valve closing position decreases. For this reason, the valve element 21
The impact when A is seated on the valve seat 3A by the second electromagnetic coil 11 can be reduced.

The control circuit 27 outputs a pulse-shaped holding signal Sb3 having a smaller duty ratio than the shock mitigation signal Sb2 to the second electromagnetic coil 11 when the valve body 21A holds the seated state. As a result, the current ib 'flowing through the second electromagnetic coil 11 is further reduced as compared with when the shock mitigation signal Sb2 is output, but the valve body 2
1A can be stopped at the valve closing position against the biasing spring 8.

Further, since the valve body position detecting device 22 is mounted on the electromagnetic driving device 5 and is detachably provided, the adjusting screw 12 can be adjusted appropriately with the valve body position detecting device 22 removed. The neutral position of the body 21A can be easily adjusted.

In the above embodiment, the case where the Hall element 24 is used as the magnetic sensor has been described as an example. However, the present invention is not limited to this. For example, a magnetic resistance element or the like may be used instead of the Hall element. May be used.

[0064]

As described in detail above, according to the first aspect of the present invention, the driving device is provided with the valve body position detecting means for detecting the position of the valve body, and the valve body position control means is provided with the valve body position detecting means. The amount of the valve-closing signal supplied to the second electromagnetic coil during the period before the valve element is seated on the valve seat until the valve element is seated is reduced by using the detection signal from the detection means. This makes it possible to reduce the electromagnetic attraction of the second electromagnetic coil just before sitting on the valve seat, and to reduce the shock when the valve element is seated on the valve seat. Therefore, noise when the valve element is seated can be reduced, and the life of the valve element, the valve seat, and the like can be extended.

According to the second aspect of the present invention, the valve body position detecting means is constituted by the magnet connected to the valve body and the magnetic sensor fixedly provided near the magnet. The distance between the magnet and the magnetic sensor changes according to the position of the body, and the magnetic flux density around the magnetic sensor also changes. Therefore, the position of the valve body can be detected by the magnetic sensor.

According to the third aspect of the present invention, the valve closing signal is constituted by the valve closing start signal, the shock mitigation signal, and the holding signal. The valve closing signal amount supplied to the electromagnetic coil can be reduced as compared to when the valve closing start signal is being output. Therefore, the speed at which the valve element moves toward the valve closing position immediately before the valve element is seated can be reduced, and noise and impact when the valve element is seated can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an electromagnetically driven valve according to an embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view showing the valve element position detecting device in FIG. 1 in an enlarged manner in a state where the valve element is at a neutral position.

FIG. 3 is an enlarged vertical sectional view of the same position as FIG. 2 showing the valve body position detecting device in an enlarged manner in a state where the valve body is at a valve closing position.

FIG. 4 is an enlarged vertical sectional view of the same position as FIG. 2 showing the valve body position detecting device in an enlarged manner in a state where the valve body is at a valve opening position.

FIG. 5 is a characteristic diagram showing a valve closing signal of a control circuit, a current of an electromagnetic coil, a detection signal of a processing circuit, and an output signal of a Hall element according to the embodiment.

FIG. 6 is a longitudinal sectional view showing a conventional electromagnetically driven valve.

FIG. 7 is a characteristic diagram showing a valve closing signal of a control circuit and a current of an electromagnetic coil according to a conventional technique.

FIG. 8 is a characteristic diagram showing a spring force of a biasing spring and an electromagnetic attraction with respect to a position of a valve body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head (valve seat member) 3 Port 3A Valve seat 5 Electromagnetic drive (drive) 7 Moving disk (movement element) 10 1st electromagnetic coil 11 2nd electromagnetic coil 21A Valve 22 Valve position detecting device (Valve element position detecting means) 24 Hall element (magnetic sensor) 25 Magnet 26 Drive circuit 27 Control circuit

Claims (3)

[Claims] A valve seat member having a port formed with a valve seat;
A valve body which is detachably seated on the valve seat to open and close the port of the valve seat member, and a driving device provided on the valve seat member for driving the valve body between a valve opening position and a valve closing position. A moving element provided in connection with the valve element, and urging the valve element toward a neutral position between the valve opening position and the valve closing position via the moving element. A biasing spring, a first electromagnetic coil that attracts the mover in one direction against the biasing spring and drives the valve body toward a valve-opening position, and the movement against the biasing spring. A second electromagnetic coil that drives the valve body toward the valve closing position by sucking the child in another direction, and outputting a valve opening signal to the first electromagnetic coil when opening the valve body, When the valve is closed, a valve closing signal is output to the second electromagnetic coil to control the position of the valve body. In the lubrication device, the driving device is provided with a valve element position detecting means for detecting a position of the valve element, and the valve element position control means uses a detection signal from the valve element position detecting means to immediately before the valve element is seated. An electromagnetic drive type wherein a valve closing signal amount supplied to the second electromagnetic coil is reduced during a period from when the valve body is seated to reduce a shock when the valve body is seated on the valve seat. valve. 2. The valve element position detecting means comprises a magnet connected to the valve element and a magnetic sensor fixed near the magnet and detecting a magnetic flux density by the magnet. 2. The electromagnetically driven valve according to 1. 3. A valve closing signal output from the valve element position detecting means includes a pulse-shaped valve closing start signal output between a neutral position and a time immediately before the valve element is seated, and a valve element being seated. A pulse-like shock mitigation signal that is output from just before being seated and has a smaller duty ratio than the valve-closing start signal,
3. The electromagnetically driven valve according to claim 1, wherein the valve is constituted by a pulse-shaped holding signal output when the valve body is held in a seated state and having a duty ratio smaller than the shock mitigation signal.