JP2006336766A - Electromagnetic drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic drive unit wherein a movable iron core is smoothly slid in a long cylinder portion of a yoke without hitting it at one side and a non-magnetic resin layer is applied to the outer peripheral face of the movable iron core with improved machining accuracy and reduced machining cost. <P>SOLUTION: The electromagnetic drive unit comprises the movable iron core 54 cantilevered and supported on the long cylinder portion 36 of the yoke so as to be slidably guided and a fixed iron core 16 coaxial with the movable iron core and having an annular protruded edge 19 at the peripheral edge extending to the long cylinder portion of the yoke for guiding the movable iron core. A 0.1 mm or more clearance C is provided throughout the periphery between the annular protruded edge and the movable iron core in the radial direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electromagnetic drive unit having a solenoid assembly.

In this type of electromagnetic drive unit, the fixed iron core and the movable iron core are arranged coaxially, and the movable iron core can be connected to and separated from the fixed iron core by power supply control that varies the excitation force of the solenoid to the fixed iron core. ing.
And, this movable iron core is housed in a bottomed tube made of a non-magnetic material, and a technique for reducing the sliding resistance by guiding the movable iron core on the inner peripheral surface of the bottomed tube at the time of contact and separation is known. (See Patent Document 1).

Further, when the processing accuracy of the bottomed tube is low, it is difficult to arrange the fixed iron core and the movable iron core coaxially, and in this case, the driving force of the electromagnetic drive unit may be unstable, An electromagnetic drive unit having a configuration in which a nonmagnetic resin layer is applied to the outer peripheral surface of a movable iron core instead of a bottomed tube made of a nonmagnetic material has been proposed by the present applicant (see Patent Document 2).
According to the electromagnetic drive unit disclosed in Patent Document 2, a yoke having a long cylindrical portion is arranged coaxially with respect to the fixed iron core, and the peripheral edge of the fixed iron core extends to the long tube portion side of the yoke to form an annular protruding edge. The movable iron core is cantilevered by the long cylindrical portion and is slidably guided through the nonmagnetic resin layer, and the tip is formed to improve the magnetic characteristics. It is arrange | positioned so that it may be guided to an edge.
Japanese Patent Laid-Open No. 10-213254 JP 2004-232793 A

By the way, in the case of the electromagnetic drive unit disclosed in Patent Document 2, the non-magnetic resin layer applied to the outer peripheral surface of the movable iron core is a thin film, so that its coating is very difficult and requires a great processing cost. In addition, if a certain degree of film thickness is to be secured, there is a problem that the thickness is likely to vary and the processing accuracy is poor.
If the thickness of the resin layer is likely to vary in this way, when the movable iron core slides in the long cylindrical portion of the yoke, the sliding resistance increases in the thick portion of the resin layer, or the resin layer is unevenly worn. There are problems and it is not desirable.

Accordingly, it can be said that it is desirable to coat the resin layer as thinly as possible.
However, on the other hand, the solenoid does not always excite the fixed iron core, and thus the annular rim, uniformly. Therefore, the excitation force of the fixed iron core is biased. The yoke tends to slide while being biased against the inside of the long cylindrical portion of the yoke. At this time, if the resin layer is thin, there is a problem that the resin layer may be peeled off on the side of the biased contact.

  The present invention has been made to solve such a problem, and an object of the present invention is to allow the movable iron core to smoothly slide within the long cylindrical portion of the yoke without uneven contact, and to provide an outer peripheral surface of the movable iron core. Another object of the present invention is to provide an electromagnetic drive unit capable of improving the processing accuracy and reducing the processing cost of a nonmagnetic resin layer applied to the substrate.

  In order to achieve the above object, in the electromagnetic drive unit according to claim 1 of the present invention, the fixed iron core is disposed coaxially with the fixed iron core, and the outer peripheral surface thereof is covered with a nonmagnetic resin layer. A yoke having a movable iron core and a long cylindrical portion that is arranged coaxially with respect to the fixed iron core, encloses the movable iron core and cantileverly supports the movable iron core through the resin layer. And a coil disposed so as to surround the fixed iron core, the movable iron core, and the long cylindrical portion of the yoke, and the movable iron core is connected and separated by exciting and demagnetizing the fixed iron core by controlling power feeding to the coil. An electromagnetic drive unit comprising: a solenoid assembly to be fixed, wherein the fixed iron core has an annular projecting edge that extends toward a long cylindrical portion of the yoke and guides the movable iron core at a peripheral edge. Diameter of the edge and the movable core Clearance is characterized in that it is set to more than 0.1mm over the entire circumference.

As described above, when the radial clearance between the annular protruding edge extending around the periphery of the fixed core and the movable core is set to 0.1 mm or more over the entire circumference, the excitation force of the fixed core is biased. However, the lateral component of the exciting force acting on the movable iron core is reduced, and the movable iron core is prevented from being biased and attracted to the annular protruding edge.
Preferably, the clearance is 0.1 mm or more and less than 0.2 mm, so that the exciting force acting on the movable iron core is ensured satisfactorily.

The electromagnetic drive unit according to claim 2 is characterized in that, in claim 1, the thickness of the resin layer is set to 0.01 mm or more and less than 0.1 mm.
That is, when the lateral component of the exciting force acting on the movable iron core is reduced and the movable iron core is biased and can no longer be attracted to the annular projecting edge, the movable iron core slides smoothly within the long cylindrical portion of the yoke. Thus, even if the thickness of the nonmagnetic resin layer applied to the outer peripheral surface of the movable iron core is reduced to 0.01 mm or more and less than 0.1 mm, the resin layer is well protected without wear.

  According to the electromagnetic drive unit of the first aspect, even if the exciting force of the fixed iron core is biased, the lateral component of the exciting force acting on the movable iron core is reduced, and the movable iron core is biased and attracted to the annular projecting edge. Can be prevented. Thereby, the movable iron core can be smoothly slid within the long cylindrical portion of the yoke without uneven contact, and the nonmagnetic resin layer applied to the movable iron core can be well protected without uneven wear.

  According to the electromagnetic drive unit of the second aspect, even if the thickness of the non-magnetic resin layer applied to the outer peripheral surface of the movable iron core is reduced to 0.01 mm to 0.1 mm, the resin layer is good without wear Thus, by forming the resin layer thin in this way, the processing cost can be greatly reduced, and further, the processing accuracy of the resin layer can be improved, and the movable iron core can be attached to the long cylinder of the yoke. It can be made to slide more smoothly in the part.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of an electromagnetic valve 10 using an electromagnetic drive unit according to the present invention. This solenoid valve 10 is a three-port, two-position directional control valve that operates in an electromagnetically operated manner. In the figure, one of the two positions (the state at the time of demagnetization) is closer to the A side than the center line. The other supply position (state during excitation) is shown on the B side.

The electromagnetic valve 10 is used for various controls, and is suitable for, for example, mini-excavator cab interference prevention / depth control, hydraulic piston / motor tilt point angle control, control valve spool / throttle valve control, and the like.
Further, the electromagnetic valve 10 includes a direction control valve unit 11 and an electromagnetic drive unit 12 that is mechanically connected to one end side to operate the direction control valve unit 11.

The electromagnetic drive unit 12 includes a disk-shaped solenoid base 14 (hereinafter referred to as a base 14). The base 14 includes an end wall 15 that connects the directional control valve unit 11 to the outer surface thereof, and a fixed iron core 16 that is formed integrally with a central portion of the end wall 15.
The fixed iron core 16 is formed to project from the end wall 15 in a columnar shape in the direction opposite to the direction control valve unit 11. A through-hole 18 is formed coaxially in the center of the fixed iron core 16, and the through-hole 18 extends in the axial direction thereof and opens at the outer surface of the end wall 15, that is, the outer end surface and the inner end surface 16 a of the fixed iron core 16. Yes.

  The fixed iron core 16 includes an annular protruding edge 19 that integrally protrudes in the axial direction from the peripheral edge of the inner end face 16a. The annular projecting edge 19 is formed mainly to improve the magnetic characteristics, and the outer diameter gradually decreases toward the tip, while the inner diameter is configured to be constant along the axial direction of the fixed iron core 16. In other words, the tip outer shape of the annular projecting edge 19 forms a truncated cone shape, while the inner end face 16a and the inner peripheral surface 19a of the annular projecting edge 19 form a cylindrical hollow portion. Thus, the annular projecting edge 19 has a function as a guide for the movable iron core 54 described later.

An annular spacer 20 is disposed on the inner end surface 16 a of the fixed iron core 16, and a cylindrical hollow portion in the annular protrusion 19 is communicated with the through hole 18 of the fixed iron core 16 with the spacer 20 interposed therebetween. ing. The spacer 20 is made of a nonmagnetic material and has a function of separating the fixed iron core 16 and a movable iron core 54 described later.
A cylindrical yoke 34 with a bottom is mounted on the base 14 coaxially with the base 14. Specifically, the yoke 34 is integrally formed of a cylindrical outer peripheral wall 35, a guide long cylindrical portion (long cylindrical portion) 36, a disk-shaped flange portion 38 and a convex portion 39, and the outer peripheral wall 35 extending from the peripheral edge of the flange portion 38. The open end 35a of the base 14 is fitted to the peripheral edge of the end wall 15 of the base 14.

The guide long cylindrical portion 36 has a smaller diameter than the outer peripheral wall 35, is formed in a cylindrical shape coaxial with the outer peripheral wall 35 and further coaxial with the fixed iron core 16, and extends from the flange portion 38 to the fixed iron core 16 side. It opens in the part side 36c, and the concentric hole 36a is formed in the inside.
The convex portion 39 has a cylindrical shape that is coaxial with the guide long tube portion 36 and has substantially the same outer diameter, and extends from the collar portion 38 in the opposite direction to the guide long tube portion 36, that is, so as to protrude to the outside. A concentric hole 39a communicating with the concentric hole 36a is formed inside.

  A screw 40 is screwed into the convex portion 39 so as to close the concentric hole 39a. Specifically, a part of the screw 40 protrudes from the convex part 39 in a state where the screw 40 is screwed to the convex part 39, and a lock nut 41 is screwed to the protruding part with a washer 42 and an O-ring 43 interposed therebetween. And fixed to the convex portion 39. A conical protrusion 40a is formed at the tip of the screw 40 toward the concentric hole 36a.

A cylindrical solenoid assembly 21 for energizing the fixed iron core 16 is accommodated between the outer peripheral wall 35 and the guide long cylindrical portion 36 so as to be coaxial with the outer peripheral wall 35 and the guide long cylindrical portion 36.
The solenoid assembly 21 includes a bobbin 22 and a coil 24 wound around the bobbin 22.

Specifically, one end of the solenoid assembly 21 is accommodated in a cylindrical space defined by the outer peripheral surface of the fixed iron core 16, the inner surface of the end wall 15, and the inner peripheral surface of the outer peripheral wall 35. More specifically, the one end is in contact with the end wall 15, an annular recess is formed on the contact surface, and an O-ring 32 is disposed in the recess.
The bobbin 22 has a stepped inner peripheral surface, a small-diameter portion 22a located in the center in the axial direction, two large-diameter portions 22b and 22c sandwiching the small-diameter portion 22a in the axial direction, and a small-diameter portion 22a The taper portion 22d is connected to the large diameter portion 22b.

  The tapered portion 22d is reduced in diameter at the same rate of change as the tip of the annular protruding edge 19 of the fixed iron core 16 when viewed in the same axial direction, and is located with a gap between the tip of the annular protruding edge 19. ing. The large-diameter portion 22b is externally fitted to the fixed iron core 16, while the large-diameter portion 22c is externally fitted to the guide long cylindrical portion 36, and an O-ring 33 is interposed at the end of the large-diameter portion 22c. ing. And the internal diameter of the small diameter part 22a is comprised a little larger than the internal diameter of the cyclic | annular protrusion 19 mentioned later.

  A through hole 38a is formed in the collar portion 38, and a pair of connection terminals 46 extend through the through hole 38a through an electrically insulating sleeve. One end of the connection terminals 46 is a coil of the solenoid assembly 21. 24 is electrically connected. On the outer surface of the flange portion 38, an electrically insulating cover 48 is molded and arranged so as to cover a part of the convex portion 39 and a part of the connection terminal 46 in addition to the outer surface of the flange portion 38. Yes.

A part of the cover 48 is provided with a peripheral wall 48 a surrounding the connection terminal 46 in an exposed state, and the peripheral wall 48 a constitutes a male plug together with the connection terminal 46. Thus, if this male plug and a female plug (not shown) are inserted, power can be supplied to the coil 24 from the outside.
Further, as shown in FIG. 1, an accommodation chamber 56 is formed above the inner end surface 16a of the fixed iron core 16 from a hollow portion in the annular projecting edge 19, a hollow portion in the small diameter portion 22a of the bobbin 22, and a concentric hole 36a. In this accommodation chamber 56, a cylindrical movable iron core 54 is accommodated coaxially with the fixed iron core 16. Specifically, the outer peripheral surface of the movable iron core 54 is coated with a resin layer 55 having a uniform thickness, and the other end of the movable iron core 54 that is separated from the fixed iron core 16 is attached to the guide long tube portion 36 via the resin layer 55. It is cantilevered and is configured to be slidable in the axial direction by being guided by the guide long cylindrical portion 36 in the concentric hole 36a.

In addition, an annular spacer 51 is interposed in the accommodation chamber 56 so that one side surface is in contact with the convex portion 39 and located on the other end side of the movable iron core 54, and at the discharge position shown on the A side in FIG. The other end of the movable iron core 54 is in contact with the other side surface of the spacer 51.
The movable iron core 54 is formed with a through hole 110 that opens concentrically with the concentric hole 36a at both end faces.

  The push rod 57 is press-fitted into the through-hole 110 so that only about half of the push rod 57 is buried, so that the push rod 57 can operate integrally with the movable iron core 54. Specifically, the push rod 57 is configured to have a two-surface portion 57a in which the tip portion of the round bar is left as it is and the two surfaces are processed in parallel, and a part of the two-surface portion 57a extends from the through hole 110. It is press-fitted so as to be exposed to the outside.

  A coil-shaped subspring 58 is interposed between the rear end located in the through hole 110 of the push rod 57 and the front end of the screw 40 so that one end is engaged with the protrusion 40a. 58 urges the movable iron core 54 toward the fixed iron core 16 along the axis. On the other hand, the front end of the push rod 57 extends through the spacer 20 and the through hole 18 and is in contact with the end surface of the valve spool 83 of the direction control valve unit 11.

As shown in an enlarged view of the X region in FIG. 1, a predetermined interval between the movable iron core 54 and the inner peripheral surface 19 a of the annular projecting edge 19 is provided on one end side of the movable iron core 54 facing the fixed iron core 16. A clearance (gap) C is set.
When the predetermined clearance C is set between the movable iron core 54 and the annular projecting edge 19 as described above, when the fixed iron core 16 is excited by the solenoid assembly 21 and the movable iron core 54 moves to the fixed iron core 16 side. Compared with the case where the movable iron core 54 and the inner peripheral surface 19a of the annular projecting edge 19 are in contact with each other, the magnetic force of the excited annular projecting edge 19 is less likely to act on the movable iron core 54, and the movable iron core 54 is moved to the annular projecting edge 19 side. The lateral component force to be attracted, that is, the excitation lateral component force is reduced. Thus, the movable iron core 54 can slide smoothly in the guide long cylinder portion 36.

Specifically, the clearance C is set as follows.
FIG. 3 shows the relationship between the stroke of the movable iron core 54 and the excitation lateral component force during excitation when the clearance C is changed from 0.05 mm to 0.15 mm.
According to the figure, when the clearance C is as small as 0.05 mm, when the stroke of the movable iron core 54 becomes large, that is, when it approaches the annular projecting edge 19, the excitation lateral component force suddenly increases, and the clearance If C is slightly larger than 0.1 mm, even if the movable iron core 54 approaches the annular projecting edge 19, the excitation lateral component force does not change so much. If the clearance C is further increased to 0.15 mm, the excitation lateral component is increased. It can be seen that the force hardly changes.

Thus, if the clearance C is set to 0.1 mm or more, it is possible to suppress the excitation lateral component force acting on the movable iron core 54 as small as possible when approaching the annular projecting edge 19.
FIG. 4 shows experimental results of the relationship between the clearance C and the excitation lateral component force when the excitation current value I is changed to I1, I2, I3 (I1>I2> I3).
According to the figure, as the clearance C increases, the excitation lateral component force itself decreases in a hyperbolic shape. Therefore, in order to secure the excitation lateral component force acting on the movable iron core 54 and thus the excitation force to a certain extent, the upper limit of the clearance C is preferably set to about 0.2 mm, for example. That is, the clearance C is preferably set in a range of 0.1 mm or more and less than 0.2 mm.

The resin layer 55 is made of a nylon resin, and the thickness thereof is set to a range of, for example, 0.01 mm or more and less than 0.1 mm, which is smaller than the clearance C.
The resin layer 55 can be formed by a known method, and a detailed description of the processing method is omitted here, but the material is not limited to the above.
Note that a minute clearance is provided between the resin layer 55 and the guide long cylindrical portion 36, and if the thickness of the resin layer 55 is changed, the minute clearance cannot be maintained. In consideration of not affecting the clearance C, for example, the inner diameter dimension of the guide long cylindrical portion 36 may be appropriately adjusted according to the thickness of the resin layer 55.

The direction control valve unit 11 is connected to the above-described electromagnetic drive unit 12 by coupling a sleeve-shaped valve casing 62 to the base 14.
Specifically, a peripheral wall 64 extends from the end wall 15 of the base 14, and the peripheral wall 64 has a female screw portion 65 on its inner peripheral surface, while the valve casing 62 is an outer peripheral surface facing the peripheral wall 64. The valve casing 62 is directly connected to the base 14 by screwing the male screw portion 66 of the valve casing 62 into the female screw portion 65.

Thus, in the valve casing 62, the end portion on the male screw portion 66 side is closed by the end wall 15, while the opposite end portion of the male screw portion 66 is closed by the end plate 68.
Inside the valve casing 62, a supply chamber 72, an output chamber 74, and a drain chamber 76 are formed in order from the end wall 15 side to the end plate 68 side, and valves that partition these chambers 72, 74, 76 are formed. Small diameter sealing surfaces 78, 80, and 82 are formed on the inner peripheral surface of the casing 62. Further, the valve casing 62 includes three ports that open at the outer peripheral surface thereof, that is, a supply port 84, an output port 86, and a drain port 88. These three ports are the supply chamber 72 and the output described above, respectively. The chamber 74 and the corresponding one of the drain chambers 76 communicate with each other.

A valve spool 83 is coaxially accommodated inside the valve casing 62, and the valve spool 83 is accommodated via a return spring 90 so as to be slidable in the axial direction. The front end of the push rod 57 is in contact with the end surface of the valve spool 83 on the end wall 15 side, so that the valve spool 83 is mechanically connected to the movable iron core 54 via the push rod 57.
The valve spool 83 has two land portions 92 and 94 that are separated from each other in the axial direction at an intermediate portion near the output port 86. Of these, the outer peripheral surface of one land portion 92 is formed on the valve casing 62 when the valve spool 83 is on the end wall 15 side in the valve casing 62 (discharge position) as shown on the A side in FIG. It is possible to seal between the supply chamber 72 and the output chamber 74 in cooperation with the sealing surface 80. Further, as shown on the B side in FIG. 1, the outer peripheral surface of the other land portion 94 is moved to the end plate 68 side in the valve casing 62 against the urging force of the return spring 90 in the valve casing 62. Sometimes (supply position) it is possible to seal between the output chamber 74 and the drain chamber 76 in cooperation with the sealing surface 82 of the valve casing 62.

The valve casing 62 is surrounded by a case (not shown) including flow paths separately connected to the three ports 84, 86, 88, and an O-ring externally fitted to the valve casing 62 is provided between these flow paths. 96, 98.
Hereinafter, the operation of the above-described electromagnetic valve 10 and the operation of the present invention will be described.
In operating the solenoid valve 10, first, the solenoid valve 10 is connected to a power source. This power supply may be either a DC power supply or an AC power supply. For example, DC12V or DC24V can be used as the DC power supply, and AC100V (50/60 Hz) or AC200V can be used as the AC power supply.

When power is not supplied to the coil 24, that is, at the discharge position shown on the A side in FIG. 1, the movable iron core 54 is biased to the spacer 51 side via the push rod 57 by the return spring 90. .
When power is supplied from the power source to the coil 24 via the connection terminal 46, a magnetic field (excitation force) is generated by the coil 24 to excite the fixed iron core 16, and the movable iron core 54 is attracted by the attraction force corresponding to the amount of current. Sucked into. Accordingly, the outer peripheral surface of the movable iron core 54 is guided to the guide long cylindrical portion 36 through the resin layer 55 and is displaced toward the fixed iron core 16.

Incidentally, as described above, a clearance C set between 0.1 mm and less than 0.2 mm is provided between the movable iron core 54 and the annular projecting edge 19 so that the excitation lateral component force acting on the movable iron core 54 does not change greatly. In this case, even if the movable iron core 54 slides and approaches the annular projecting edge 19, a large excitation lateral component force does not act on the movable iron core 54.
In this way, when a large excitation lateral component force does not act on the movable iron core 54, normally, the annular projecting edge 19 is hardly excited uniformly over the entire circumference, and the movable iron core 54 is excited laterally. This tendency tends to be biased toward the strong component side, and this tendency becomes more prominent as the excitation lateral component force increases. However, such a bias of the movable core 54 is prevented, and the movable core 54 is separated from the fixed core 16. While being held coaxially, it slides smoothly in the guide long tube portion 36 without uneven contact.

Thus, the nonmagnetic resin layer 55 applied to the movable iron core 54 can be well protected without uneven wear.
Here, as described above, the thickness of the resin layer 55 is set to, for example, 0.01 mm or more and less than 0.1 mm, and is set to a relatively thin film thickness as compared with the conventional case.
However, even if the resin layer 55 is thin as described above, as described above, the uneven contact of the movable iron core 54 in the guide long cylindrical portion 36 is suppressed, and the uneven wear of the resin layer 55 applied to the movable iron core 54 is prevented. Therefore, the resin layer 55 of the thin film can be well protected without peeling off.

Accordingly, when the thickness of the resin layer 55 is set to be relatively thick (for example, 0.1 mm or more), the resin layer 55 must be formed by laminating the resin layers, which increases the number of processing steps. However, by reducing the thickness of the resin layer 55, the number of stacking processes can be reduced (for example, once), and the processing cost can be greatly reduced.
On the other hand, FIG. 5 shows three types of variations in the actual film thickness around the movable core 54 with respect to the three set film thicknesses (No. 1 coat, No. 2 coat, and No. 3 coat) of the resin layer 55. The measurement results are shown for the materials (for example, a, b, and c). According to the figure, as the set film thickness of the resin layer 55 is increased, the actual film thickness variation degree increases, It can be seen that the degree of variation decreases as the value increases.

Thus, by thinning the resin layer 55, it is possible to improve the processing accuracy of the resin layer 55 by reducing the variation in film thickness, and the movable iron core 54 is slid more smoothly in the guide long cylindrical portion 36. It can be moved.
When the movable iron core 54 is displaced toward the fixed iron core 16 in this way, the displacement of the movable iron core 54 is transmitted to the valve spool 83 via the push rod 57, the return spring 90 is compressed, and the valve spool 83 is moved to the supply position. Moving.

As a result, the valve spool 83 is in the supply position shown on the B side in FIG. 1, and the hydraulic oil at this time passes through the valve casing 62 from the supply port 84 connected to the pump and is connected to the output port 86. It flows toward.
When the power supply to the coil 24 is stopped, the magnetic field generated by the coil 24 disappears, the fixed iron core 16 is demagnetized, and the valve spool 83 moves to the discharge position by the extension force of the compressed return spring 90, and the movable iron core. 54 moves away from the fixed iron core 16 and returns to the inoperative position.

Accordingly, the valve spool 83 is in the discharge position shown on the A side in FIG. 1, and the hydraulic oil at this time passes through the valve casing 62 from the output port 86 connected to the actuator, and the tank connected to the drain port 88. It flows toward.
As described above, according to the electromagnetic valve 10 according to the present invention, the clearance C of 0.1 mm or more and less than 0.2 mm is provided between the movable iron core 54 and the annular projecting edge 19 in the electromagnetic drive unit 12. Therefore, even if the movable iron core 54 slides and approaches the annular projecting edge 19, a large excitation lateral component force can be prevented from acting on the movable iron core 54. Thus, the movable iron core 54 can be smoothly slid without uneven contact in the guide long tube portion 36, and the resin layer 55 applied to the movable iron core 54 can be well protected without uneven wear.

Accordingly, since the thickness of the resin layer 55 can be set to a thin film of, for example, 0.01 mm or more and less than 0.1 mm, the processing cost of the resin layer 55 can be significantly reduced, and the resin The processing accuracy of the layer 55 can be improved.
In addition, this invention is not limited to the above-mentioned embodiment, A various deformation | transformation is possible.
For example, the length of the guide long cylindrical portion 36 can be appropriately changed to a length that allows the movable iron core 54 to be cantilevered, and the number of ports and the number of switching positions of the electromagnetic valve 10 are also limited to the above-described embodiment. It is not a thing.

It is a longitudinal cross-sectional view of the solenoid valve using the electromagnetic drive unit in embodiment of this invention, Comprising: The A side is a figure which shows the time of the electric power feeding to a solenoid at the time of non-power feeding to a solenoid. It is an enlarged view of the X area | region of FIG. It is an experimental result which shows the relationship between the stroke of a movable iron core at the time of the excitation at the time of changing the clearance C, and an excitation lateral component force. It is an experimental result which shows the relationship between clearance C and excitation lateral component force. It is a measurement result which shows the dispersion | variation degree of the actual film thickness around a movable iron core with respect to the setting film thickness of a resin layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Solenoid valve 11 Directional control valve unit 12 Electromagnetic drive unit 16 Fixed iron core 19 Annular protruding edge 21 Solenoid assembly 34 Yoke 36 Guide long cylinder part (long cylinder part)
54 Movable iron core 55 Resin layer C Clearance

Claims (2)

A fixed iron core,
A movable iron core disposed coaxially with the fixed iron core, the outer peripheral surface of which is covered with a nonmagnetic resin layer;
A yoke that is arranged coaxially with respect to the fixed iron core, includes a long cylindrical portion that slidably guides the movable iron core through the resin layer, including the movable iron core and cantilevered;
A solenoid having a coil disposed so as to surround the fixed iron core, the movable iron core, and the long cylindrical portion of the yoke, and energizing and demagnetizing the fixed iron core by power supply control to the coil to contact and separate the movable iron core An electromagnetic drive unit comprising an assembly,
The fixed iron core has an annular protruding edge that extends toward the long cylindrical portion of the yoke and guides the movable iron core at the periphery,
An electromagnetic drive unit characterized in that a radial clearance between the annular protruding edge and the movable iron core is set to 0.1 mm or more over the entire circumference.   The electromagnetic drive unit according to claim 1, wherein a thickness of the resin layer is set to 0.01 mm or more and less than 0.1 mm.

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