JPH07151257A - Electromagnetic control valve - Google Patents

Abstract

PURPOSE:To provide an electromagnetic control valve which permits the control with high precision for the fluid flow rate with a simple structure. CONSTITUTION:The outer ring 8b of a ball bearing 8 which supports the magnetic attraction side of a shaft 11 is formed from a magnetic body. The end part on the magnetic attraction side of a moving core 10 is formed into a taper form so that the outside diameter reduces toward the magnetic attraction side, and the shaft 11 penetrates in the axial direction through the center part. An electric current is supplied into a coil 5 from the state where electric current is not supplied into the coil 5, and when a ring 12 makes contact with the outer ring 8b of the ball bearing 8 on the magnetic attraction side, the gap between the attraction side end surface of the moving core 10 and the opposed surface of the outer ring 8b of the ball bearing 8 becomes 1mm or less. The sufficient magnetic attraction force in the axial direction is generated by the increase of the flow of the magnetic flux in the axial direction, and the constant magnetic attraction characteristic an be obtained independently of the axial direction position of the moving core 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic control valve for controlling the flow rate of fluid.

[0002]

2. Description of the Related Art Conventionally, in this type of electromagnetic control valve, when a moving core is driven by a magnetic attraction force generated in a solenoid portion, a spool housed in a sleeve is driven together with the moving core, and the magnetic attraction force The resultant force with the biasing force of the spring that biases the spool in the direction opposite to the magnetic attraction force causes the spool to reciprocate, thereby adjusting the fluid flow rate. At this time, ideally, as shown in FIG. 7C, it is desirable that the stroke of the moving core, that is, the axial position, be determined substantially in proportion to the current value.
For that purpose, as shown in FIG. 7A, the current input to the solenoid portion and the magnetic attraction force for driving the moving core by the magnetic flux generated in the solenoid portion are substantially proportional to each other. As shown, this magnetic attraction force needs to be constant regardless of the stroke of the moving core. In particular, since the moving core moves in the axial direction by the magnetic attraction force, it is necessary to devise to make the magnetic attraction force constant regardless of the stroke of the moving core. An electromagnetic control valve as described below is known so that the suction force is constant regardless of the stroke of the spool.

This electromagnetic control valve has a shaft made of a non-magnetic material, which is formed separately from the spool. The shaft is penetrated and press-fitted so that both ends of the moving core of the magnetic material receive a magnetic attraction force. is doing. Both ends of the protruding part of the shaft are supported by ball bearings so that the frictional resistance received by the shaft is reduced and the shaft can move extremely smoothly in the axial direction, and one end of the shaft that receives the magnetic attraction force of the moving core abuts the spool. I am letting you.

Further, in the other electromagnetic control valve, as the moving core sucks and moves, and the lapping amount between the lateral surface of the moving core and the facing magnetic body increases, the radial attractive force increases and the axial attractive force increases. In order to prevent the movement of the moving core from decreasing, the suction side end of the moving core is formed in a taper shape whose outer diameter becomes smaller toward the tip. Further, another electromagnetic control valve provides a magnetic attraction force between the attraction side end face of the moving core and this magnetic substance face by providing a facing face of the magnetic body facing and approaching the attraction side end face of the moving core. It is generated to further prevent the axial suction force from decreasing. However, in this electromagnetic control valve, when the suction side end surface of the moving core and the facing surface of the magnetic body come into contact with each other, the suction side end surface of the moving core and the facing surface of the magnetic body are attracted by a strong suction force, and There is a problem that even if the current is cut off, the current is not separated immediately. As a countermeasure against this, a non-magnetic member may be interposed between the end surface of the moving core on the suction side and the facing surface. As a method of interposing the non-magnetic member, for example, a non-magnetic member is press-fitted into a spool-integrated moving core, or a non-magnetic member is arranged as a separate component between the moving core and the ball bearing. There is a way. At this time, when the moving core moves to the most attraction side, the gap between the moving core and the facing surface of the magnetic material, that is, the axially interposed member of the magnetic material member greatly affects the magnetic attraction characteristics.

[0005]

In such a conventional electromagnetic control valve, in the case where the moving core has a taper shape in which the outer diameter becomes smaller toward the tip, the suction side end of the moving core becomes smaller than the diameter of the moving core. A decrease in the axial attraction force is prevented to some extent as the amount of wrapping with the magnetic body facing in the direction increases, but this is still insufficient. Further, in the electromagnetic control valve that prevents the attraction of the suction side end surface of the moving core and the magnetic body facing the suction side end surface with the non-magnetic member interposed, the suction side end surface of the moving core and the facing magnetic body are separated from each other. The nonmagnetic material must be thin to some extent in order to increase the magnetic attraction force generated as it approaches.
If it is too thin, there is a problem that the assembling property and durability deteriorate.

The present invention has been made to solve the above problems, and provides an electromagnetic control valve that enables highly accurate control of a fluid flow rate with a simple structure.

[0007]

The electromagnetic fluid control valve of the present invention for achieving the above object is a sleeve formed in a tubular shape and having an opening serving as a passage for a fluid, and sliding on an inner wall of the sleeve. A spool having a large-diameter portion and a small-diameter portion that are movably supported, and a magnetic drive portion that is formed in a tubular shape, is fixed to the axial end portion of the sleeve, and includes a magnetic body around which a coil is wound, A moving core made of a magnetic material, which is formed in a tubular shape and has an annular groove formed on the end surface of the magnetic attraction side and a taper portion whose outer diameter decreases toward the magnetic attraction side at the end portion of the magnetic attraction side, and the groove. A ring made of a non-magnetic material that fits in the groove so as to project from the shaft, and a shaft made of a non-magnetic material that is fixed by axially penetrating the moving core and is capable of contacting the axial end of the spool. When,
A support member fixed to the magnetic drive unit so as to support both ends of the shaft so as to be slidable in the axial direction smoothly, wherein the support member supports the magnetic attraction side of both ends of the shaft, And a support member having a magnetic attraction side facing surface that faces the moving core in the axial direction and is made of a magnetic material.

[0008]

According to the electromagnetic control valve of the present invention, when the moving core is attracted by the magnetic flux generated in the solenoid,
Since the shaft is supported slidably in the axial direction by the support member, frictional resistance when the shaft reciprocates in the axial direction is reduced. Further, since the end portion of the moving core on the suction side is formed in a tapered shape, the magnetic attraction force is unlikely to change regardless of the axial position of the moving core. Further, in the support member that supports the magnetic attraction side of the shaft, the opposing surface that faces the moving core is formed of a magnetic material, so that the decrease in the magnetic attraction force in the axial direction is further reduced. At this time, by fitting the non-magnetic material so as to project into the groove provided on the end surface of the moving core on the suction side, it is possible to prevent the moving core and the supporting member from being attracted and to prevent the gap between the moving core and the supporting member. Can be made smaller.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment in which the electromagnetic control valve of the present invention is applied to a hydraulic control valve of a valve timing adjusting device for an internal combustion engine. 1 shows a state in which a magnetic attraction force is not generated without passing a current through the solenoid portion 1, and FIG. 2 shows a state in which a current is passed through the solenoid portion 1 to generate a magnetic attraction force to operate the moving core. Show.

The hydraulic control valve includes a solenoid portion 1 and a solenoid portion 1 which generate a magnetic attraction force by supplying an electric current.
Driven by the magnetic attraction force generated in the control chambers 21 and 22, the flow rate of oil supplied to the control chambers 21 and 22 and the flow rate of oil discharged from the control chambers 21 and 22 are adjusted.
Consists of. In the solenoid section 1, a yoke 3 which is a cylindrical magnetic body and a stator 4 are connected by caulking and fixed to form a magnetic circuit, and an inner diameter portion 3a of the yoke 3 and a central portion 4a of the stator 4 and the yoke 3 are formed. A hollow cylindrical coil 5 is built in between the outer diameter portion 3b. The coil 5 has its winding end connected to the terminal 7, and is integrally molded with the resin portion 6.

The inner diameter portion 3a of the yoke 3 and the central portion 4a of the stator 4 are opposed to each other with a space gap 9 therebetween in the axial direction. Ball bearings 8 are press-fitted and fixed to the inner wall of the inner diameter portion 3a of the yoke 3 and the inner wall of the central portion 4a of the stator 4, respectively. Ball bearing 8 is ball 8a
And an outer ring 8b that holds the ball 8a.
The outer ring 8b on the arrow B side in FIG. 1 is made of a magnetic material.

A moving core 10 made of a magnetic material is arranged in a space surrounded by the inner wall of the central portion 4a of the stator 4 and the pair of ball bearings 8. Moving core 1
1 has a taper portion 10a formed at the end on the magnetic attraction side indicated by the arrow B in FIG. 1 so that the outer diameter becomes smaller toward the magnetic attraction side, and an annular counterbore hole 10b is formed on the tip surface of the taper portion 10a.
Are formed. At the center of the moving core 10, a non-magnetic shaft 11 is press-fitted and fixed so as to penetrate the moving core 10 in the axial direction. The protruding portions 11a and 11b of the shaft 11 are bearing-supported by the ball bearings 8, respectively, and the moving core 10 can move smoothly in the axial direction together with the shaft 11. The non-magnetic rings 12 and 13 are press-fitted and fixed to the shaft 11 and are in contact with both ends of the moving core 10.
The ring 12 is further embedded in the counterbore 10b and slightly protrudes from the moving core 10. Ring 1
2 and 13 are ideally 2 because they hold the press-fitting load.
A thickness of mm is required, and the amount of protrusion of the ring 12 from the counterbore hole 10b is set to 1 mm or less.

One end of the sleeve 14 of the spool control valve 2 is crimped and fixed to the yoke 3, and an adjusting nut 16 is screwed into the inside of the other end. The sleeve 14 is formed with a plurality of openings 14a, 14b, 14c, 14d, 14e communicating with a plurality of passages for allowing oil to pass through at a predetermined wall surface position. The hydraulic pressure release passage 31 includes the opening 14a and the oil tank 1.
9, the hydraulic passage 32 is connected to the opening 14b and the control chamber 2.
1, the hydraulic pressure supply passage 33 communicates the opening 14c with the oil pump 18, the hydraulic passage 34 communicates the opening 14d with the control chamber 22, and the hydraulic release passage 35 has the opening 14e.
And the oil tank 19 are communicated with each other.

A spool 15 is supported on the inner wall of the sleeve 14 so as to be slidable in the axial direction. Spool 15
It is composed of large diameter portions 15a, 15b, 15c, 15d, which are lands having a diameter substantially the same as the inner diameter of the sleeve 14, and small diameter portions connecting these large diameter portions. A spring 17 is interposed between one end of the spool 15 and the adjusting nut 16, and the biasing force of the spring 17 causes the spool 1 to move.
The other end of 5 abuts on the shaft 11, and the ring 13 is pressed against the outer ring 8b of the ball bearing 8 on the arrow A side shown in FIG. Further, the biasing force of the compression coil spring 17 can be adjusted by adjusting the tightening degree of the adjustment nut 16.

FIG. 1 shows a state in which no current is supplied to the coil 5, the magnetic attraction force is not acting on the moving core 10, and the spool 15 and the moving core 10 are compressed by the compression coil spring 17 and indicated by the arrow in FIG. It is biased in the A direction. At this time, the opening 14 of the spool control valve 2
c and the opening 14d communicate with each other, and the opening 14b and the opening 1
The oil from the pump 18 is pressure-fed to the control chamber 22 by disconnecting between 4c. At the same time, the opening 14a and the opening 14b are communicated with each other, and the opening 14b and the opening 14c are cut off from each other, so that the oil in the control chamber 21 is removed from the tank 1.
It is discharged to 9.

FIG. 2 shows a state where the moving core 10 is moved by supplying an electric current to the coil 5 from the state shown in FIG. A magnetic attraction force is generated between the inner diameter portion 3a of the yoke 3 and the moving core 10, and the moving core 10 and the spool 1
5 resists the urging force of the spring 17, moves from the state shown in FIG. 1 to the magnetic attraction side in the direction of arrow B in FIG. 1, and moves to the position shown in FIG. Moving core 10 is ring 1
2 and the outer ring 8b of the ball bearing 8 on the magnetic attraction side come into contact with each other to be stationary. At this time, the spool control valve 2
Between the opening 14b and the opening 14c of the
The control pressure chamber 2 is cut off by blocking between c and the opening 14d.
Oil is pumped to 1. At the same time, the opening 14d and the opening 14e communicate with each other, and the opening 14c and the opening 14d are shut off, so that the oil in the control pressure chamber 22 is discharged to the tank 19.

Next, the operation and effect of the embodiment of the present invention will be described in comparison with the comparative example. A comparative example is shown in FIGS. In the comparative example shown in FIG. 5, a ring 120 having a thickness of 2 mm capable of holding a sufficient press-fitting load is provided on the end surface of the moving core 100 on the magnetic attraction side. When a current is supplied to the coil 5 from a state in which no current is supplied to the coil 5 of the solenoid unit 1 shown in FIG. 5A, the magnetic attraction force depends on the magnitude of the current value supplied to the coil 5, as shown in FIG. Is different. The magnetic attraction force temporarily increases with the axial movement of the moving core 100, and the ring 120 shown in FIG.
Shows a tendency to decrease as it moves to a position where it comes into contact with the outer ring 8b of the ball bearing 8. This is shown in FIG. 5B in which the ring 120 is in contact with the ball bearing 8.
In the state shown in FIG. 3, the gap between the outer ring 8b of the ball bearing 8 and the suction side end surface of the moving core 100 does not become equal to or less than the thickness of the ring 120.
0 and the outer ring 8b of the ball bearing 8 do not generate a sufficient magnetic attraction force, and the magnetic attraction force in the radial direction increases as the lap amount a between the moving core 100 and the yoke 3 that faces the radial direction increases. Because it does.

On the other hand, in this embodiment, as shown in FIG.
A ring 12 having a thickness of 2 mm is embedded in the counterbore 10b of the moving core 10 so as to intervene, and the ring 12 projects by 1 mm or less from the most distal end surface of the moving core 10 on the magnetic attraction side. When a current is supplied to the coil 5 from a state in which no current is supplied to the coil 5 of the solenoid unit 1 shown in FIG. 3A, as shown in FIG. Is different. When the moving core 10 moves in the axial direction and the ring 12 comes into contact with the outer ring 8b of the ball bearing 8 as shown in FIG. 3B, the suction side end surface of the moving core 10 and the facing surface of the outer ring 8b of the ball bearing 8 come into contact with each other. Gap is less than 1mm. Therefore, the yoke 3 that faces the moving core 10 in the radial direction.
Even if the amount of wrapping a between the moving core 10 and the ball bearing 8 is increased, the magnetic flux in the axial direction is increased compared to the comparative example, so that a sufficient magnetic attraction force is generated between the moving core 10 and the outer ring 8b made of a magnetic material of the ball bearing 8. However, as shown in FIG. 4, the magnetic attraction force does not decrease, and a constant magnetic attraction force characteristic can be obtained regardless of the axial position of the moving core 10. Even in the comparative example, if the thickness of the ring 120 is reduced, it is possible to obtain the same magnetic attraction characteristic as that of the present example, but it is not practical because there is a problem that the strength during assembly and during use is reduced. .

In this embodiment, since the magnetic attraction force can be kept constant regardless of the axial position of the moving core 10,
The axial position of the moving core 10 is determined substantially in proportion to the current value supplied to the coil 5. Therefore, since the position of the spool 15 is determined by the magnitude of the current value, it is supplied to the control chambers 21 and 22 by controlling the current value.
The flow rate of oil discharged can be controlled with high accuracy.

Further, in this embodiment, the moving core 10 is supported by the ball bearings 8 at both ends and smoothly moves in the axial direction, and the axial movement range is restricted by the outer ring 8b of the ball bearing 8. As a result, the moving core 10 of the inner diameter portion 3a of the sleeve 3 and the central portion 4a of the stator 4 is
Since the space in which the ball bearing 8 and the ball bearing 8 are built is one section having substantially the same diameter, the sleeve 3 and the stator 4 can be easily formed as one object with a simple shape.

Further, in this embodiment, the non-magnetic ring 12 is interposed between the suction side end surface of the moving core 10 made of a magnetic body and the outer ring 8b of the ball bearing 8. Therefore, the magnetic attraction side end surface of the moving core 10 and the outer ring 8b of the ball bearing 8 come into contact with each other and are attracted by a strong magnetic attraction force, and even if the current of the coil 5 is cut off, the moving core 10 immediately becomes a spring. 17
It is possible to prevent the problem of not being separated by the urging force of. Further, the ring 12 is press-fitted and fixed to the shaft 11, so that the ring 12 is very easy to assemble.

[0022]

The solenoid control valve of the present invention described above has a simple structure and linearly approximates the characteristics of the axial position of the moving core and the electric current supplied to the solenoid portion to correspond to the electric current value supplied to the solenoid portion. Since the accurate axial position of the moving core can be grasped, the flow rate of the fluid can be controlled with high accuracy, and the assembling property is also improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment in which an electromagnetic control valve of the present invention is applied to a hydraulic control valve of a valve timing adjusting device at the most retarded angle.

FIG. 2 is a cross-sectional view showing the most advanced angle of an embodiment in which the electromagnetic control valve of the present invention is applied to a hydraulic control valve of a valve timing adjusting device.

FIG. 3 is a sectional view showing a main part of an electromagnetic control valve of the present invention. (A) shows the most retarded angle, and (B) shows the most advanced angle.

FIG. 4 is a characteristic diagram showing a relationship between a moving core axial position and a magnetic attraction force according to a position embodiment of the present invention.

FIG. 5 is a sectional view showing a main part of an electromagnetic control valve of a comparative example. (A) shows the most retarded angle, and (B) shows the most advanced angle.

FIG. 6 is a characteristic diagram showing a relationship between a moving core axial position and a magnetic attraction force in a comparative example.

FIG. 7A is a characteristic diagram showing an ideal relationship between a current supplied to a solenoid part and a magnetic attraction force generated in the solenoid part by the supplied current. FIG. 6B is a characteristic diagram showing an ideal relationship between the magnetic attraction force generated in the solenoid and the axial position of the moving core. FIG. 6C is a characteristic diagram showing an ideal relationship between the current supplied to the solenoid portion and the axial position of the moving core.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solenoid part 2 Spool control valve 3 Yoke (magnetic drive part) 4 Stator (magnetic drive part) 5 Coil (magnetic drive part) 8 Ball bearing (supporting member) 10 Moving core 10a Tapered part 10b Counterbore hole (groove) 11 Shaft 12 Ring 13 Ring 14 Sleeve 14a Opening 14b Opening 14c Opening 14d Opening 14e Opening 15 Spool 15a Large diameter (land) 15b Large diameter (land) 15c Large diameter (land) 15d Large diameter Section (land section)

[Procedure amendment]

[Submission date] December 13, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

Claims (1)

[Claims] 1. A sleeve formed in a tubular shape and having an opening serving as a fluid passage, a spool slidably supported by an inner wall of the sleeve and having a large diameter portion and a small diameter portion, and a tubular shape. A magnetic drive unit that is formed and fixed to the axial end of the sleeve, and that is composed of a magnetic body around which a coil is wound; and a cylindrical shape that forms an annular groove on the end surface of the magnetic attraction side and magnetic attraction. A moving core made of a magnetic material having a taper portion whose outer diameter decreases toward the magnetic attraction side at a side end, and a ring made of a non-magnetic material fitted in the groove so as to protrude from the groove, A shaft, which is fixed through the moving core in the axial direction and is made of a non-magnetic material that can abut against the axial end of the spool, and supports both ends of the shaft so as to be slidable in the axial direction. Fixed to the magnetic drive In the supporting member that supports a magnetic attraction side of both ends of the shaft, a supporting member that has a magnetic attraction side facing surface that axially faces the moving core is formed of a magnetic material. And an electromagnetic control valve.