JP2005155794A - Linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase response property of an electromagnetic hydraulic control valve 1, suppress occurrence of biting into a shaft 14 by a foreign matter, and prevent intrusion of a foreign matter into a plunger storage chamber A. <P>SOLUTION: The plunger storage chamber A and a breathing hole 21 are mutually communicated by a breathing passage 16 having large flow passage area to change space volume of the plunger storage chamber A by travel of a plunger 5 or a shaft 14 quickly with reduced resistance and increase response property of the electromagnetic hydraulic control valve 1. Since it is unnecessary to let oil or remaining air flow into slide clearances B1, B2, size of the slide clearances B1, B2 can be reduced to suppress improper slide of the shaft 14 due to biting of a foreign matter. A filter 22 is arranged in an inlet passage 16a which is an inlet of the breathing passage 16 to prevent intrusion of a foreign matter into the plunger storage chanber A, thereby preventing improper operation of the electromagnetic actuator 4 and maintaining demand characteristics of the electromagnetic actuator 4 for a long time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a linear actuator that displaces a driven body in the axial direction by the operation of an electromagnetic actuator. For example, the present invention is a technique suitable for use in an electromagnetic valve in which a valve device is driven by an electromagnetic actuator. The present invention relates to a technique suitable for use in an electromagnetic hydraulic control valve that switches and adjusts hydraulic pressure by a valve.

(Conventional technology)
With reference to FIG. 6, the structure of the main part of a conventional linear actuator will be described.
The linear actuator shown in FIG. 6 moves a driven body (for example, a valve or the like) in the axial direction together with the shaft J3 by displacing the shaft J3 in the axial direction by an electromagnetic actuator J1 and a spring J2.
The electromagnetic actuator J1 has a plunger accommodating chamber A that accommodates the plunger J4 so as to be movable in the axial direction. In order to displace the plunger J4 in the axial direction inside the coil J5, the space volume of the plunger accommodating chamber A (plunger It is necessary to change the volume of the space formed between the storage chamber A and the plunger J4.
The housing J6 for housing the driven body has a breathing hole J7 communicating with the inside and the outside. The breathing hole J7 and the plunger housing chamber A are connected to the shaft J3 and the bearing (in FIG. 6, the first and second bearings). J8 and J9) are communicated with each other via sliding clearances B1 and B2 (gap in a portion in sliding contact with the shaft J3). When the plunger J4 is displaced in the axial direction, the breathing fluid (for example, oil, air, etc.) is supplied to and discharged from the plunger housing chamber A through the sliding clearances B1 and B2, and the plunger housing chamber A The space volume changes and the plunger J4 can be displaced in the axial direction.

  On the other hand, it is known that an axially extending groove (not shown) is formed on the inner peripheral surface of the bearing supporting the shaft J3 (see, for example, Patent Document 1). In this groove, when foreign matter (for example, abrasion powder) enters the sliding clearances B1 and B2, the foreign matter is accumulated in the groove by sliding of the shaft J3, and the foreign matter is caught in the sliding clearances B1 and B2. Is to prevent This groove also acts as a breathing passage that communicates the breathing hole J7 and the plunger housing chamber A.

(Trouble of conventional technology)
When the sliding clearances B1 and B2 are set small, the foreign matter is difficult to enter the sliding clearances B1 and B2, and therefore the possibility that the shaft J3 causes a sliding failure due to the biting of the foreign matter is low.
However, if the sliding clearances B1 and B2 are small, the flow passage area through which the respiration fluid flows is small, so that the respiration fluid cannot be rapidly supplied to and discharged from the plunger housing chamber A, and the operating resistance of the plunger J4 increases. Responsiveness cannot be obtained.

On the contrary, when the sliding clearances B1 and B2 are large, since the flow passage area through which the respiration fluid flows is large, the operating resistance of the plunger J4 is reduced, and an excellent response is obtained.
However, since the sliding clearances B1 and B2 are large, there is a high possibility that foreign matter having a large particle diameter will enter the sliding clearances B1 and B2, and the sliding failure may occur in the shaft J3 due to the biting of foreign matter. is there.

On the other hand, even when a breathing passage is provided by a groove as in the technique of Patent Document 1, since the flow passage area through which the breathing fluid flows is large, the operating resistance of the plunger J4 is reduced, and excellent responsiveness is obtained.
However, the provision of the breathing passage increases the possibility that a foreign substance enters the plunger accommodating chamber A together with the breathing fluid. When a magnetic foreign substance (for example, iron powder or iron pieces such as wear powder or cutting powder) enters the plunger accommodating chamber A as a foreign substance together with the breathing fluid, the intruded magnetic foreign substance may constitute a part of the magnetic circuit. .
If the magnetic foreign matter that has entered the plunger housing chamber A constitutes a part of the magnetic circuit, the magnetic force acting on the plunger J4 is lost due to the magnetic short, or the balance of magnetism acting on the plunger J4 is lost. As a result, the plunger J4 slides strongly with the surrounding member (for example, the sealing cup guide J10) and the plunger J4 is prevented from moving in the axial direction, and the required characteristics for the electromagnetic actuator J1 are obtained. It may not be possible.
In addition, foreign matter that is not a magnetic foreign matter may accumulate in the plunger housing chamber A or bite into the plunger housing chamber A, thereby preventing the movement of the plunger J4 and causing a malfunction.
International Publication No. 01/027511 Pamphlet

  The present invention has been made to solve the above-mentioned problems, and its purpose is to (1) increase the responsiveness by increasing the flow passage area through which the respiratory fluid flows, and (2) biting of the shaft by foreign matter. And (3) to provide a linear actuator capable of preventing foreign matter from entering a plunger accommodating chamber inside the electromagnetic actuator.

[Means of claim 1]
(1) A linear actuator employing the means of claim 1 is a breathing passage in which the plunger accommodating chamber and the breathing hole in the electromagnetic actuator have a larger flow area than the flow area of the sliding clearance between the shaft and the bearing. It communicates via.
Since the respiratory passage has a large flow path area through which the respiration fluid flows, when the space volume of the plunger accommodation chamber varies due to the movement of the plunger, the respiration fluid can be rapidly supplied to and discharged from the plunger accommodation chamber. For this reason, the operating resistance of the plunger can be reduced, and excellent responsiveness can be obtained.
(2) Since a breathing passage having a large flow path area is provided separately from the sliding clearance, the sliding clearance can be reduced. This makes it difficult for foreign matter to enter the sliding clearance, so that it is possible to suppress a problem that the shaft causes a sliding failure due to the biting of the foreign matter.
(3) Since a filter for blocking the passage of foreign matter is provided in the respiratory passage for supplying and discharging the respiratory fluid, the foreign matter does not enter the plunger accommodating chamber in the electromagnetic actuator together with the respiratory fluid. As a result, malfunction of the electromagnetic actuator can be prevented, and the required characteristics of the electromagnetic actuator can be maintained over a long period of time.

[Means of claim 2]
The linear actuator bearing adopting the means of claim 2 comprises a first bearing and a second bearing, and a filter is provided on a member constituting the first bearing.

[Means of claim 3]
The linear actuator bearing adopting the means of claim 3 comprises a first bearing and a second bearing, and the second bearing close to the plunger is provided by joining two members. And a filter is pinched | interposed and supported by the two members which comprise a 2nd bearing.

[Means of claim 4]
The linear actuator bearing adopting the means of claim 4 comprises a first bearing and a second bearing, and the filter is supported by being sandwiched between the first bearing and the second bearing.

[Means of claim 5]
The linear actuator employing the means of claim 5 is an electromagnetic valve.
That is, the housing is a valve housing in which a fluid passage is formed, and the driven body is displaced in the axial direction inside the valve housing, thereby switching the fluid passage (or opening / closing of the fluid passage or the passage of the fluid passage). The valve device is configured by a valve housing and a valve, and this valve device is driven by an electromagnetic actuator.

[Means of claim 6]
The linear actuator employing the means of claim 6 is an electromagnetic hydraulic control valve.
That is, the valve housing is a sleeve in which an oil input / output port or discharge port is formed, and the valve is displaced in the axial direction inside the valve housing to switch the input / output port or discharge port (or input / output or The valve device is constituted by a valve housing and a valve, and this valve device is driven by an electromagnetic actuator.

The linear actuator according to the best mode 1 is a driven object (for example, a ball valve, a spool valve, etc.), an apparatus to be driven (for example, a valve device, a spool valve, etc.) having a housing, and an electromagnetic having a coil, a plunger, and a stator. An actuator; a shaft that transmits the displacement of the plunger in the axial direction to the driven body; a bearing of the shaft; and a biasing unit that biases the plunger and the driven body in a direction in which the opposing distance between the plunger and the stator increases. .
The electromagnetic actuator includes a plunger accommodating chamber that accommodates the plunger.
The housing includes a breathing hole (or a discharge port) that allows communication between the inside and the outside of the atmospheric pressure.
The plunger accommodating chamber communicates with the breathing hole through a breathing passage having a flow passage area larger than the flow passage area of the sliding clearance between the shaft and the bearing.
The breathing passage is provided with a filter that prevents passage of foreign substances contained in the breathing fluid flowing through the breathing passage.

A first embodiment will be described with reference to FIGS. In the following embodiments, an electromagnetic valve is shown as an example of a linear actuator, and an electromagnetic hydraulic control valve is shown as a specific example of the electromagnetic valve.
The electromagnetic hydraulic control valve 1 is mounted on a hydraulic controller of an automatic transmission, for example, and oil (hydraulic) is supplied to a hydraulic actuator that engages and disengages hydraulic engagement elements such as a multi-plate clutch and a multi-plate brake of the automatic transmission. Control that supplies and discharges oil, and supplies and discharges oil (hydraulic pressure) to the advance chamber or retard chamber of a hydraulic actuator for adjusting the camshaft advance angle, which is mounted on a hydraulic controller of a variable valve timing device (VVT, etc.) It is a valve.

FIG. 1 is a cross-sectional view of the main part of the electromagnetic hydraulic control valve 1, and the structure of the electromagnetic hydraulic control valve 1 will be described with reference to FIG.
The electrohydraulic control valve 1 includes a valve housing (sleeve) 2, a valve device (an example of a driven object: not shown) 3 and an electromagnetic actuator 4 that drives the valve in the axial direction. Is provided.
The valve housing 2 has a substantially cylindrical shape, and is formed with an input / output port (not shown) or a discharge port serving as an oil supply / discharge port.

  The valve is slidable in the axial direction within the valve housing 2. When the valve is a spool type, the valve has an outer diameter dimension that substantially matches the inner diameter dimension of the valve housing 2 (or variable port opening). Large diameter part (land). Further, the spool is provided with a small-diameter portion having a diameter smaller than that of the large-diameter portion, and the communication state of the input / output port or the discharge port is changed according to the position of the small-diameter portion in the axial direction. The spool valve is displaced in the axial direction by the electromagnetic actuator 4 to control the shut-off state of the input / output port or the discharge port by the large diameter portion and the communication state of the input / output port or the discharge port by the small diameter portion. Controls the hydraulic pressure of the actuator.

The electromagnetic actuator 4 includes a plunger 5, a stator 6, a coil 7, a yoke 8, a side gap core 9, and a connector (not shown).
The plunger 5 is formed of a magnetic metal (for example, iron: a ferromagnetic material constituting a magnetic circuit) that is magnetically attracted to the stator 6, and is disposed inside the coil 7 (specifically, for oil seals). It is supported so as to be slidable in the axial direction on the inner side of the cup guide 11.

The stator 6 includes a substantially disk-shaped plate 12 that is sandwiched between the valve housing 2 and the coil 7 and a substantially cylindrical suction core 13 that guides the magnetic flux of the plate 12 to the vicinity of the plunger 5. .
The plate 12 and the suction core 13 are both magnetic metal (for example, iron: a ferromagnetic material constituting a magnetic circuit), and a main gap MG (magnetic suction gap) is formed between the plunger 5 and the suction core 13. Is done. In this embodiment, an example in which the plate 12 and the suction core 13 are configured as separate parts is shown, but the plate 12 and the suction core 13 may be provided as one part.
The end of the suction core 13 is formed with a recess that is inserted without contacting the end of the plunger 5. When the plunger 5 enters the recess, the plunger 5 is sucked into the end of the stator 6. In this case, the plunger 5 and a part of the stator 6 are provided so as to intersect in the axial direction. The shape of the suction core 13 or the end of the plunger 5 (on the main gap MG side) may be a flat surface, a cone, a spherical surface, a free curved surface, or a composite shape thereof.

The coil 7 is a magnetic force generating means that generates a magnetic force when energized and magnetically attracts the plunger 5 to the stator 6, and is formed by winding a large number of enamel wires around a resin bobbin 7a.
The yoke 8 is a magnetic metal (for example, iron: a ferromagnetic material constituting a magnetic circuit) that covers the periphery of the coil 7, and is coupled to the valve housing 2 by caulking of the claw portion 8a formed on the left side of FIG. Is.
The side gap core 9 covers the periphery of the plunger 5 and transfers magnetic flux to and from the plunger 5 around the plunger 5. A side gap SG (magnetic flux transfer) is provided between the plunger 5 and the side gap core 9. Gap) is formed. In this embodiment, an example in which the yoke 8 and the side gap core 9 are configured as separate parts is shown, but the yoke 8 and the side gap core 9 may be provided as a single part.
The connector is a means for performing electrical connection with a control device that controls the electrohydraulic control valve 1 via a connection line, and terminals connected to both ends of the coil 7 are arranged inside the connector.

  The electrohydraulic control valve 1 includes a plunger 5 and a shaft 14 that transmits axial displacement of the valve. The shaft 14 of this embodiment shows an example in which the right end in FIG. 1 abuts against the plunger 5, but may be fixed to the plunger 5 by press fitting or the like. On the other hand, the left end of the shaft 14 in FIG. 1 may be fixed to the valve by press fitting, or provided integrally with the valve (the shaft 14 itself is a valve or a component of the valve). May be. Further, when the valve is biased toward the plunger 5 by a biasing means such as a spring or a hydraulic reaction force, the valve and the shaft 14 may be in contact with each other.

The shaft 14 is supported by a resin collar 15 (corresponding to the first bearing) on the side away from the plunger 5 (left side in FIG. 1) and on the side close to the plunger 5 (right side in FIG. 1). It is supported by a suction core 13 (corresponding to a second bearing). That is, the collar 15 and the suction core 13 constitute a bearing for the shaft 14.
The collar 15 is fixed inside the valve housing 2. Further, the suction core 13 is fixed to the inside of the plate 12 sandwiched and fixed between the valve housing 2 and the coil 7 by press fitting or the like.
The breathing passage 16 provided in the bearing will be described later.

  The electromagnetic hydraulic control valve 1 includes a spring 17 (corresponding to an urging means) that urges the plunger 5 in a direction in which the facing distance (main gap MG) between the plunger 5 and the stator 6 is separated. The spring 17 of this embodiment is disposed between the collar 15 and the shaft 14 and applies a biasing force to the shaft 14 to move to the right side in FIG. 1, and biases the plunger 5 to the right side in FIG. A spring may be disposed between the suction core 13 and the plunger 5. Further, a spring may be disposed between the valve housing 2 on the side different from the plunger 5 and the valve to apply a biasing force to the valve, the shaft 14 and the plunger 5. In addition, the spring 17 may be omitted when a biasing force is not particularly required due to a hydraulic reaction force to the valve.

When the coil 7 is OFF, the electrohydraulic control valve 1 stops when the spool and the plunger 5 are displaced to the coil 7 side (right side in FIG. 1) by the biasing force of the spring 17.
In this stop state, the maximum gap of the main gap MG is determined and the valve is positioned with respect to the valve housing 2.
In addition, the code | symbol 18 shown in FIG. 1 is an O ring for sealing.

[Features of Example 1]
Since the plunger 5 moves in the axial direction inside the electromagnetic actuator 4, a plunger housing chamber A for housing the plunger 5 so as to be displaceable in the axial direction is provided inside the electromagnetic actuator 4. The plunger accommodating chamber A is a room surrounded by the cup guide 11 and the suction core 13.
Here, the diameter of the plunger 5 is different in the axial direction, and the diameter of the plunger housing chamber A is also different in the axial direction according to the diameter. Further, when the plunger 5 is displaced in the axial direction, the amount of penetration of the shaft 14 that enters the plunger accommodating chamber A is also displaced. For this reason, when the plunger 5 is displaced in the axial direction, the volume of the space of the plunger accommodating chamber A (the space surrounded by each member: the first space A1 + the second space A2 + the third space A3) changes.

The first space A1 on the stator 6 side (left side in FIG. 1) of the plunger 5 and the second space A2 on the non-stator 6 side (side different from the first space A1: right side in FIG. 1) of the plunger 5 The plunger inner passage 5a is formed so as to pass through the center through a radial groove 5b formed in the contact surface of the shaft 14, and is connected between the first space A1 and the second space A2. In this way, oil (working fluid) or residual air can travel freely.
The third space A3 and the first space A1 on the outer periphery of the plunger 5 communicate with each other via a plunger outer peripheral groove 5c formed on the outer periphery of the plunger 5, and the first space A1 and the third space A3 are connected to each other. Oil or residual air can be freely passed between them.
In this embodiment, the radial groove 5b is formed on the end face of the plunger 5, but it may be formed on the end face of the shaft 14. Further, an internal passage penetrating in the axial direction may be formed in a portion other than the axial center of the plunger 5 to communicate the first space A1 and the second space A2, or a groove extending in the axial direction on the outer peripheral surface of the plunger 5. The second space A2 and the third space A3 may be communicated with each other.

  The valve housing 2 has a breathing hole or a discharge port (drain port) 21 through which the inside and the outside of the atmospheric pressure communicate with each other to supply and discharge oil (working fluid) or internal residual air.

The first space A1 in the plunger accommodating chamber A is provided so as to communicate with the breathing hole 21 through the breathing passage 16 provided in the bearing (collar 15 and suction core 13) of the shaft 14.
The breathing passage 16 is provided with a passage area larger than the passage areas of the sliding clearances B1 and B2 between the shaft 14 and the bearing (the collar 15 and the suction core 13), and the breathing oil is mainly breathed. It flows through the passage 16.

In this embodiment, the breathing passage 16 has an inlet passage 16a communicating in the axial direction of the collar 15 and a bearing inner space 16b between the shaft 14 and the suction core 13 (this minimum clearance is larger than the sliding clearances B1 and B2. ) And a plurality of axial grooves 16c formed in the axial direction at the sliding portion (sliding clearance B2 portion) of the suction core 13 with the shaft 14. The axial groove 16c is a groove that connects the bearing inner space 16b and the first space A1 of the plunger accommodating chamber A. In this embodiment, an example is provided on the outer peripheral surface of the shaft 14. You may provide in a surrounding surface.
That is, the breathing hole 21 and the plunger housing chamber A communicate with each other via the breathing passage 16 including the inlet passage 16a → the bearing inner space 16b → the axial groove 16c, and the minimum passage area of the breathing passage 16 is as follows. The collar 15 and the suction core 13 have larger sliding clearances B1 and B2 in the axial direction, and oil or residual air actively flows through the breathing passage 16, and the sliding clearances B1 and B2 are less likely to flow oil or residual air. It is.

As described above, when the plunger 5 is displaced in the axial direction, the space volume of the plunger accommodating chamber A (the volume of the first space A 1 + the second space A 2 + the third space A 3) changes. Oil or residual air is supplied or discharged.
Every time the plunger 5 is displaced in the axial direction and the space volume of the plunger accommodating chamber A changes, oil or residual air flows through the breathing passage 16, so that foreign matter (abrasion powder, cutting, etc.) contained in the oil or residual air flows. Powder or the like) may enter the respiratory passage 16 and the plunger accommodating chamber A.
Therefore, the breathing passage 16 is provided with a filter 22 that prevents passage of foreign substances contained in the oil flowing through the breathing passage 16. As shown in FIG. 2, the filter 22 is disposed over the entire area of the inlet passage 16a, and filters all oil that passes through the inlet passage 16a. The filter 22 of this embodiment is a fine mesh (for example, # 80 to # 1000), and is insert-molded in a resin collar 15.

[Effect of Example 1]
The electromagnetic hydraulic control valve 1 of the first embodiment has the following effects.
(1) The plunger accommodating chamber A and the breathing hole 21 are provided with a breathing passage 16 having a larger passage area than the passage clearances B1 and B2 between the shaft 14 and the bearing (the collar 15 and the suction core 13). Communicate through. As described above, since the respiratory passage 16 has a large flow path area, when the space volume of the plunger housing chamber A is changed by the movement of the plunger 5, oil can be rapidly supplied to and discharged from the plunger housing chamber A. As a result, the operating resistance of the plunger 5 can be reduced, and the operating response of the plunger 5 and thus the response of the electromagnetic hydraulic control valve 1 can be improved.

  (2) Since the breathing passage 16 having a large flow path area is provided separately from the sliding clearances B1 and B2, the sliding clearances B1 and B2 can be reduced. This makes it difficult for foreign matter to enter the sliding clearances B1 and B2, so that it is possible to suppress the sliding failure of the shaft 14 that occurs when the foreign matter bites into the sliding clearances B1 and B2.

  (3) Since the filter 22 for preventing the passage of foreign matter is provided in the inlet passage 16a corresponding to the oil inlet in the breathing passage 16, foreign matter together with the oil or residual air is contained in the breathing passage 16 and in the plunger accommodating chamber A. Does not penetrate inside. As a result, malfunction of the electromagnetic actuator 4 can be prevented, the required characteristics of the electromagnetic actuator 4 can be maintained for a long time, and the reliability of the electromagnetic hydraulic control valve 1 can be improved.

  That is, the electrohydraulic control valve 1 to which the present invention is applied has excellent responsiveness, suppresses malfunction of the shaft 14 due to foreign matter biting, and further prevents foreign matter from entering the plunger accommodating chamber A inside the electromagnetic actuator 4. Can prevent intrusion.

A second embodiment will be described with reference to FIGS. In the following embodiments, the same reference numerals as those in the first embodiment denote the same functional objects.
In the first embodiment, the filter 22 is disposed on the collar 15 corresponding to the first bearing. However, in the second embodiment, the filter 22 is disposed inside the suction core 13 corresponding to the second bearing. Is.
In the second embodiment, a breathing passage 16 is formed inside the suction core 13, and a filter 22 is disposed in the breathing passage 16 in the suction core 13 to filter oil passing through the breathing passage 16 in the suction core 13. To do.
In order to form the respiratory passage 16 inside the suction core 13 and arrange the filter 22, the suction core 13 is composed of two members (a main core material 13 a and a sub-core material 13 b).
The main core material 13a has a structure in which a cylindrical concave portion is formed in the center portion on the plunger 5 side, and a substantially cylindrical sub core material 13b is press-fitted and fixed inside the concave portion. A plurality of (in this embodiment, five as shown in FIG. 4) protrusions 13c are formed on the sub-core member 13b to be inserted into the outer periphery of the filter 22 disposed inside the filter chamber 16d. The inner peripheral surface of the secondary core material 13b supports the shaft 14, and a sliding clearance B2 is formed between the secondary core material 13b and the shaft 14.

The breathing passage 16 inside the suction core 13 is connected to a filter chamber 16d (communicating with a bearing inner space 16b in which the spring 17 is disposed) formed between the main core material 13a and the auxiliary core material 13b in the axial direction, A plurality of groove passages 16e (communicating with the plunger housing chamber A) formed in the axial direction around the core material 13b.
That is, the entire breathing passage 16 is composed of the inlet passage 16a → the bearing inner space 16b → the filter chamber 16d → the groove passage 16e, and communicates the breathing hole 21 and the plunger housing chamber A.

The filter 22 is disposed in the filter chamber 16d and supported by being sandwiched between the axial directions of the main core material 13a and the sub-core material 13b, and is made of, for example, a non-woven fiber formed in a cylindrical shape.
Even when the second embodiment is adopted, the oil flowing through the breathing passage 16 passes through the filter 22 when flowing through the filter chamber 16d, so that the same effect as the first embodiment can be obtained.

A third embodiment will be described with reference to FIG.
In the third embodiment, the filter 22 is sandwiched and supported between the collar 15 corresponding to the first bearing and the axial direction of the suction core 13 corresponding to the second bearing. The filter 22 of the third embodiment has a substantially ring disk shape, is provided with a mesh or non-woven fiber, and is disposed so that the filter 22 covers the suction core 13 side of the inlet passage 16a.
An annular groove 16f and a radial groove 16g for guiding the oil that has passed through the filter 22 to the bearing inner space 16b are formed on the contact surface of the filter 22 in the suction core 13.
That is, the entire breathing passage 16 is composed of the inlet passage 16a → the annular groove 16f → the radial groove 16g → the bearing inner space 16b → the axial groove 16c, and communicates the breathing hole 21 and the plunger housing chamber A. .
Even if the third embodiment is adopted, the oil flowing through the respiratory passage 16 passes through the filter 22, so that the same effect as the first embodiment can be obtained.

[Modification]
In the above embodiment, the example in which the breathing passage 16 is formed on the outer peripheral side of the shaft 14 has been shown, but the breathing passage 16 may be formed inside the shaft 14. In that case, by arranging the filter 22 in the breathing passage 16 inside the shaft 14, the same effect as in the above embodiment can be obtained.
The structure of the electromagnetic actuator 4 shown in the above embodiment is an example for explaining the embodiment, and may be another structure. For example, the plunger 5 may be disposed in the axial direction of the coil 7.
In the above embodiment, the spool (driven body, valve, etc.) is displaced toward the non-coil 7 side when the coil 7 is turned on. Conversely, the spool (driven body, valve, etc.) is turned on when the coil 7 is turned on. Etc.) may be displaced toward the coil 7 side.

In the above embodiment, the electromagnetic hydraulic control valve 1 is shown as an example of the electromagnetic valve. However, the switching of fluids other than oil (for example, water, air, exhaust gas, etc.), fluid intermittent, fluid flow rate adjustment. You may apply this invention to the solenoid valve which performs.
Furthermore, the present invention may be applied to a linear actuator that drives another driven body (a member that moves linearly) with the electromagnetic actuator 4 instead of the valve.

It is sectional drawing which follows the axial direction which shows the principal part of an electrohydraulic control valve (Example 1). It is a front view of a color (Example 1). (Example 2) which is sectional drawing which follows the axial direction which shows the principal part of an electrohydraulic control valve. (Example 2) which is principal part sectional drawing of the direction orthogonal to the axial direction in a filter part. (Example 3) which is sectional drawing which follows the axial direction which shows the principal part of an electrohydraulic control valve. It is sectional drawing which follows the axial direction which shows the principal part of an electrohydraulic control valve (conventional example).

Explanation of symbols

1 Electro-hydraulic control valve (linear actuator, solenoid valve)
2 Valve housing (sleeve)
3 Valve device (device to be driven)
4 Electromagnetic actuator 5 Plunger (mover)
6 Stator 7 Coil 13 Suction core (second bearing)
13a Main core material (one of the two members constituting the second bearing)
13b Sub-core material (the other of the two members constituting the second bearing)
14 Shaft 15 Collar (first bearing)
16 Breathing passage 17 Spring (biasing means)
21 Breathing hole 22 Filter A Plunger receiving chamber B1, B2 Sliding clearance

Claims (6)

(A) a driven body supported so as to be displaceable in the axial direction, a drive target device including a housing for housing the driven body;
(B) a coil that generates a magnetic force when energized, a plunger that is movable in the axial direction, a stator that guides the magnetic force generated by the coil to an opposing position in the axial direction of the plunger, and the magnetic force generated by the coil An electromagnetic actuator for attracting the plunger to the stator;
(C) a shaft that is disposed between the driven body and the plunger, and transmits the axial displacement of the plunger to the driven body;
(D) a bearing that supports the shaft so as to be axially displaceable;
(E) urging means for urging the plunger and the driven body in a direction in which the facing distance between the plunger and the stator is increased;
(F) The electromagnetic actuator includes a plunger accommodating chamber that accommodates the plunger so as to be displaceable in the axial direction.
(G) The housing includes a breathing hole communicating between the inside and the outside of the housing,
(H) The plunger accommodating chamber communicates with the breathing hole through a breathing passage having a larger flow path area than a flow passage area of a sliding clearance between the shaft and the bearing.
(I) A linear actuator characterized in that a filter for preventing passage of foreign substances contained in a respiration fluid flowing through the breathing passage is provided in the breathing passage. The linear actuator according to claim 1,
The bearing includes a first bearing that supports the shaft on a side away from the plunger, and a second bearing that supports the shaft on a side closer to the plunger than the first bearing,
The linear actuator according to claim 1, wherein the filter is provided on a member constituting the first bearing. The linear actuator according to claim 1,
The bearing includes a first bearing that supports the shaft on a side away from the plunger, and a second bearing that supports the shaft on a side closer to the plunger than the first bearing,
This second bearing is provided by joining two members,
The linear actuator is characterized in that the filter is supported by being sandwiched between two members constituting the second bearing. The linear actuator according to claim 1,
The bearing includes a first bearing that supports the shaft on a side away from the plunger, and a second bearing that supports the shaft on a side closer to the plunger than the first bearing,
The linear actuator is characterized in that the filter is supported by being sandwiched between the first bearing and the second bearing. In the linear actuator in any one of Claims 1-4,
The housing is a valve housing in which a fluid passage is formed;
The driven body is a valve that changes the fluid passage, opens and closes the fluid passage, or changes the passage area of the fluid passage by being displaced in the axial direction inside the valve housing.
A linear actuator comprising a valve device comprising the valve housing and the valve. The linear actuator according to claim 5,
The valve housing is a sleeve in which an oil input / output port or a discharge port is formed,
The valve is configured to change the passage area of the input / output port or the discharge port by switching or opening / closing the input / output port or the discharge port by being displaced in the axial direction inside the valve housing.
A linear actuator comprising a valve device comprising the valve housing and the valve.

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