JP2007157796A - Solenoid driving device and solenoid valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solenoid driving device and a solenoid valve which can improve the properties of a linear solenoid valve. <P>SOLUTION: The solenoid driving device comprises a coil 17, ends 18 and 19 which are arranged adjacently to the coil 17 and are formed of a magnetic substance, a yoke so arranged as to surround the coil 17 and the ends 18 and 19, and a plunger 14 so arranged as to slide on the inner peripheral wall of a hollow portion 22 formed inside in the diametric direction of a non-magnetic body and the ends 18 and 19. The plunger 14 comprises a base formed of a magnetic substance and a coating layer formed on the outer peripheral wall of the base. The coating layer is made by dispersing a nickel phosphide into fluororesin, and causing an eutectoid reaction between the two substances. Due to this structure, the plunger 14 and the inner yoke can slide on each other smoothly and thereby the plunger 14 can be moved back and forth smoothly. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solenoid driving device and a solenoid valve.

  Conventionally, for example, a hydraulic circuit of an automatic transmission has been provided with various solenoid valves. The solenoid valve includes a solenoid unit and a valve unit, and operates the valve unit by supplying current to the coil of the solenoid unit. The oil passage is opened and closed, and the oil flow rate and hydraulic pressure are adjusted.

  Next, a linear solenoid valve among the solenoid valves will be described.

  FIG. 2 is a sectional view of a conventional linear solenoid valve.

  In the figure, 10 is a linear solenoid valve, 11 is a solenoid part, and 12 is a pressure regulating valve part that constitutes a valve part that is actuated by driving the solenoid part 11. The solenoid unit 11 includes a coil assembly 113, a plunger 114 disposed so as to be movable forward and backward (movable in the left and right direction in the drawing) with respect to the coil assembly 113, and an outer yoke disposed so as to surround the coil assembly 113. 20.

  The coil assembly 113 is adjacent to the bobbin 15, the coil 17 formed by winding the winding 16 around the bobbin 15, and radially inward of the coil 17, and adjacent to the coil 17. A cylindrical end portion 118 is provided extending from the vicinity of the front end (left end in the figure) toward the rear (right side in the figure) of the coil 17, and forward (left in the figure) from the vicinity of the front end of the coil 17. A cylindrical shape for limiting the flow of magnetic flux between the end portions 118 and 119 by reducing the outer diameter between the annular end portion 119 and the end portions 118 and 119 disposed on A magnetic resistance unit 121 is provided. Note that the outer peripheral surfaces of the front end of the end portion 118 and the rear end of the end portion 119 have a tapered shape.

  A hollow portion 22 having the same diameter in the axial direction is formed in the coil assembly 113 (inwardly in the radial direction of the end portions 118 and 119 and the magnetoresistive portion 121), and the plunger 114 slides into the hollow portion 22 ( E) It is arranged to move freely.

  The plunger 114 has an outer peripheral surface having a constant diameter in the axial direction. In the plunger 114, a plunger abutting portion 172 formed at the rear end (right end in the drawing) of the spool 159 of the pressure regulating valve portion 12 is brought into contact with the center of the front end surface (left end surface in the drawing).

  By the way, the bobbin 15 is made of a non-magnetic material, and includes a protrusion 122 formed to protrude radially inward in correspondence with the magnetoresistive part 121. Therefore, in the solenoid unit 11, when a current is supplied to the coil 17, magnetic flux is generated, and a magnetic path is formed from the outer yoke 20 through the end portion 118, the plunger 114, and the end portion 119 in order to return to the outer yoke 20. Along with this, a suction portion is formed at the rear end of the end portion 119 in the magnetic path.

  On the other hand, the pressure regulating valve portion 12 is disposed at a valve body 165, the spool 159 fitted and retracted with respect to the valve body 165, and a front end of the valve body 165. The spool 159 is disposed in the valve body. An end plate 166 for preventing the 165 from being pulled out, and disposed between the end plate 166 and the front end of the spool 159, and urges the spool 159 toward the solenoid portion 11 with a predetermined spring load. A spring 167 is provided.

  The valve body 165 drains an input port p11 to which input pressure is supplied, an output port p12 for outputting output pressure to a hydraulic servo (not shown) as a supply destination, a sealed feedback port p13, and input pressure. The drain port p14 and the like are provided, and the feedback port p13 communicates with the output port p12 through a feedback oil passage (not shown), and the output pressure is supplied as the feedback pressure. The difference in area between the lands 174 and 176 of the spool 159 A corresponding feedback force is generated, and the spool 159 is biased forward by the feedback force.

  Therefore, the spool 159 receives a thrust force from the plunger 114, a spring load by the spring 167, and a feedback force by a feedback pressure, and advances and retracts integrally with the plunger 114 in a state where the plunger contact portion 172 is in contact with the plunger 114. It is done.

  When a current is supplied to the coil 17, the coil 17 attracts the plunger 114 with a predetermined suction force and causes the plunger 114 to generate a thrust. As a result, the thrust is transmitted to the spool 159 and the pressure regulating valve unit 12 is operated, so that an output pressure proportional to the current can be generated.

Incidentally, in order to improve the slidability between the inner peripheral surface of the coil assembly 113 and the outer peripheral surface of the plunger 114, the outer peripheral surface of the plunger 114 is coated with nickel phosphide (Ni-P) ( For example, see Patent Document 1.)
JP 2004-153161 A

  However, in the conventional solenoid valve, since the sliding resistance between the coil assembly 113 and the plunger 114 cannot be made sufficiently small, the plunger 114 cannot be smoothly advanced and retracted, and the pressure regulating valve portion 12 As a result, the hydraulic pressure cannot be adjusted with high accuracy. As a result, the hysteresis generated in the hydraulic pressure to be adjusted increases, and the characteristics of the linear solenoid valve are degraded.

  It is an object of the present invention to provide a solenoid driving device and a solenoid valve that can solve the problems of the conventional linear solenoid valve and improve the characteristics of the linear solenoid valve.

  Therefore, in the solenoid driving device of the present invention, a coil formed by winding a winding around a non-magnetic material, an end portion made of a magnetic material, disposed adjacent to the coil, and the coil The yoke is made of a magnetic material and is slidably disposed on the inner peripheral wall of the hollow portion formed radially inward of the non-magnetic material and the end portion. And a plunger.

  The plunger includes a base made of a magnetic material and a coating layer formed on the outer peripheral wall of the base. The coating layer is formed by dispersing and eutecting a fluororesin in nickel phosphide.

  In another solenoid drive device of the present invention, the fluororesin is polytetrafluoroethylene.

  In still another solenoid drive device of the present invention, the blending ratio of the fluororesin is set to 30% or more by mass percentage.

  In still another solenoid driving device of the present invention, a nitride layer formed by gas soft nitriding is formed on the inner peripheral wall of the hollow portion.

  In the solenoid valve of the present invention, a coil formed by winding a winding around a non-magnetic material, an end portion which is disposed adjacent to the coil and is made of a magnetic material, and the coil and the end portion are arranged. A yoke which is disposed so as to surround and is made of a magnetic material, a plunger which is slidably disposed on an inner peripheral wall of a hollow portion formed radially inward of the nonmagnetic material and the end portion, and And a valve body integrally assembled with the yoke.

  The plunger includes a base made of a magnetic material and a coating layer formed on the outer peripheral wall of the base. The coating layer is formed by dispersing and eutecting a fluororesin in nickel phosphide.

  According to the present invention, in the solenoid driving device, a coil formed by winding a winding around a non-magnetic material, an end portion that is disposed adjacent to the coil and is made of a magnetic material, and the coil The yoke is made of a magnetic material and is slidably disposed on the inner peripheral wall of the hollow portion formed radially inward of the non-magnetic material and the end portion. And a plunger.

  The plunger includes a base made of a magnetic material and a coating layer formed on the outer peripheral wall of the base. The coating layer is formed by dispersing and eutecting a fluororesin in nickel phosphide.

  In this case, the plunger includes a base made of a magnetic material and a coating layer formed on the outer peripheral wall of the base, and the coating layer is formed by dispersing and eutecting a fluororesin on nickel phosphide. The sliding between the plunger and the inner yoke is made good, and the plunger can be smoothly advanced and retracted. Therefore, the hydraulic pressure can be adjusted with high accuracy by the pressure regulating valve portion, and the characteristics of the linear solenoid valve can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 is a cross-sectional view of a linear solenoid valve according to an embodiment of the present invention, FIG. 3 is a cross-sectional view of a plunger according to an embodiment of the present invention, and FIG. 4 is a blending ratio of fluororesin and plunger of the embodiment of the present invention. It is a relationship figure with a characteristic.

  In the figure, reference numeral 10 denotes a linear solenoid valve, and the linear solenoid valve 10 is disposed, for example, in a hydraulic circuit of an automatic transmission. In the hydraulic circuit, the hydraulic pressure discharged from an oil pump (not shown) is adjusted to a line pressure by a primary regulator valve (not shown), and the line pressure is supplied to the linear solenoid valve 10 as an input pressure.

  The linear solenoid valve 10 is operated based on an electric current, and supplies a hydraulic pressure corresponding to the electric current to a hydraulic servo as an actuator of a friction engagement element (not shown) and a supply destination.

  Further, 51 is a solenoid part constituting a solenoid drive device, 12 is a pressure regulating valve part constituting a valve part actuated by driving the solenoid part 51, and the linear solenoid valve 10 is an automatic transmission (not shown). Mounted horizontally to the machine case.

  The solenoid 51 includes a coil assembly 13, a plunger 14 that can be moved forward and backward (moved in the left and right direction in the drawing) with respect to the coil assembly 13, and an outer yoke that surrounds the coil assembly 13. That is, the outer yoke 20 and the terminal tm for supplying current to the coil 17 of the coil assembly 13 are provided.

  The coil assembly 13 includes a bobbin 15, the coil 17 formed by winding the bobbin 15 with a winding 16, adjacent to the coil 17, radially inward from the coil 17, and A predetermined portion of the coil 17, in the present embodiment, a cylindrical end portion 18 arranged to extend rearward (rightward in the drawing) from the vicinity of the front end (leftward in the drawing), and the coil 17. As a predetermined portion, in the present embodiment, as an annular end portion 19 disposed forward (leftward in the drawing) from the vicinity of the front end, and a magnetoresistive portion disposed between the end portions 18 and 19. The bobbin 15 and the end portions 18 and 19 and the magnetic shielding portion 21 are integrally assembled by welding, brazing, sintering joining, adhesion, or the like. The end portion 18 constitutes a first yoke, and the end portion 19 constitutes a second yoke, and the end portions 18, 19 and the magnetic shielding portion 21 constitute an inner yoke, that is, an inner yoke 34. At least a part of the inner yoke 34 is disposed radially inward from the coil 17.

  The magnetic shielding portion 21 includes a first surrounding portion 31 that covers the thin portion 18a at the front end of the end portion 18 from the outside, a second surrounding portion 32 that covers the rear end (right end in the drawing) of the end portion 19 from the outside, and A separating portion that projects radially inward between the first and second surrounding portions 31 and 32 and faces the plunger 14 and magnetically separates the end portions 18 and 19 from each other. 33.

  As the magnetoresistive portion, instead of the magnetic shielding portion 21, a thin-walled portion in which a part of the inner yoke is thinned or a plurality of holes extending in the radial direction are provided in a part of the inner yoke. Part can be formed. In that case, the inner yoke and the perforated portion are integrally formed.

  The coil assembly 13 is formed in a cylindrical shape excluding the portion of the terminal tm, and has a constant diameter in the axial direction in the coil assembly 13 (inwardly in the radial direction of the end portions 18 and 19 and the magnetic shielding portion 21). The plunger 14 is fitted into the hollow portion 22 so as to be movable forward and backward and slidable. Therefore, the plunger 14 is supported by the coil assembly 13 in a state of being fitted in the hollow portion 22.

  Further, a nitrided layer formed by gas soft nitriding is formed on the inner peripheral wall of the hollow portion 22 that slides with the outer peripheral wall of the plunger 14. In this case, the surface roughness is increased by the gas soft nitriding, but the surface roughness (Z) of the inner peripheral wall of the hollow portion 22 before the gas soft nitriding is set in a predetermined range in advance. Even after the nitriding treatment, the surface roughness can be obtained with no problem in sliding. As a result, frictional resistance can be reduced and frictional resistance can be ensured. Further, since the surface roughness is set in a predetermined range in advance, processing for improving the surface roughness after the gas soft nitriding processing, for example, honing processing, barrel processing, and the like are not required.

  The outer yoke 20 is composed of a bottomed cylindrical body, and includes a cylindrical portion 55 and a bottom portion 56 having a circular shape, and the cylindrical portion 55 and the bottom portion 56 are formed by plastic metal processing such as deep drawing and cold forging. It is integrally formed. A notch 57 is formed in a predetermined portion in the circumferential direction of the front end of the cylindrical portion 55, and a terminal tm is attached to the coil assembly 13 through the notch 57. A caulking portion 80 is formed at the front end of the tubular portion 55, the coil assembly 13 is fitted into the outer yoke 20, the valve body 65 of the pressure regulating valve portion 12 is set, and then the caulking portion 80 and the valve body 62 are rearward. The solenoid part 51 and the pressure regulation valve part 12 are assembled | attached integrally by crimping the flange part 63 formed in the end.

  The outer circumferential surface of the plunger 14 has a constant diameter in the axial direction, and is longer than the coil 17 in the axial direction. In the plunger 14, a plunger abutting portion 72 formed at the rear end of the spool 59 of the pressure regulating valve portion 12 is brought into contact with the center of the front end surface (left end surface in the figure), and the rear end surface (in the figure). On the right end surface), a contact portion 27 formed so as to protrude from the bottom portion 56 is contacted. The surface of the contact portion 27 is subjected to a surface treatment to form an outer layer (not shown) made of a nonmagnetic material. As described above, the contact portion 27 is formed on the bottom portion 56 and the outer layer made of a nonmagnetic material is formed on the surface of the contact portion 27, so that the plunger 14 is in contact with the outer yoke 20. 14 and the contact portion 27 can be prevented from generating magnetic flux, and magnetism can be separated.

  In the present embodiment, the contact portion 27 is formed on the bottom portion 56. However, the contact portion 27 is formed on the rear end surface of the plunger 14 so as to protrude toward the bottom portion 56 side. It is also possible to form contact portions on both the outer yoke 14 and the outer yoke 20.

  In addition, a plurality of oil passages 30 having a predetermined diameter in the axial direction are formed through the plunger 14, and the front end side (left end side in the drawing) and the rear end side of the plunger 14 through the oil passage 30. (The right end side in the figure) is in communication. Therefore, as the plunger 14 is advanced and retracted, the oil on the front end side of the plunger 14 in the hollow portion 22 flows backward, or the oil on the rear end side of the plunger 14 in the hollow portion 22 flows forward. .

  The bobbin 15 and the magnetic shielding part 21 are made of a non-magnetic material. As the non-magnetic material, for example, a non-magnetic metal such as stainless steel (SUS) can be used, or a synthetic resin can be used. The end portions 18 and 19, the outer yoke 20 and the plunger 14 are made of a magnetic material, preferably a ferromagnetic material. As the ferromagnetic material, for example, electromagnetic soft iron or the like can be used. The electromagnetic soft iron contains 95% or more of pure iron, preferably about 99% or more (rounded to the first decimal place and 99% or more). used.

  By the way, an edge portion 61 having a right-angled triangular cross section is formed at the rear end of the end portion 19 as a suction portion, and the outer peripheral surface of the edge portion 61 is tapered. The outer diameter of the edge portion 61 is the largest at the front end, and becomes smaller toward the rear, and is made equal to the inner diameter of the separation portion 33 at the rear end of the edge portion 61. In this case, since the edge 61 is tapered toward the rear, magnetic saturation occurs at the edge 61.

  On the other hand, a receiving portion 32a surrounding the edge portion 61 is formed at the rear end portion of the second surrounding portion 32, and the inner peripheral surface of the receiving portion 32a is formed in a tapered shape. The inner diameter of the accommodating portion 32a is the largest at the front end, and becomes smaller toward the rear, and is made equal to the inner diameter of the separating portion 33 at the rear end of the accommodating portion 32a.

  In the present embodiment, the outer peripheral surface of the edge portion 61 and the inner peripheral surface of the accommodating portion 32a are tapered, but the outer peripheral surface and the inner peripheral surface are curved in a convex shape or a concave shape, or different. A multi-step inclined surface with an inclination angle may be used.

  The outer peripheral surface of the plunger 14 is subjected to a surface treatment, and a coating layer 70 is formed on the outer peripheral wall that is the outer periphery in the radial direction of the base 83 made of a magnetic material, that is, a ferromagnetic material.

  The coating layer 70 is made of a non-magnetic material, and is formed by, for example, plating. For example, a self-lubricating material or the like is used as a material having a small friction coefficient μ. In the plating process, a fluororesin (PTFE: polytetrafluoroethylene) is dispersed in a nickel phosphide plating solution in a mass percentage of 30% or more, and a film is formed by being eutectoid. An outer layer 27a made of a non-magnetic material is formed on the surface of the contact portion 27. If the outer layer 27a is formed by performing the plating process simultaneously with the coating layer 70, the coating of the coating layer 70 and the outer layer 27a is separately performed. The manufacturing man-hour by performing to can be reduced.

  On the other hand, the pressure regulating valve portion 12 is snapped to the valve main body 62, the spool 26 fitted to the valve main body 62 so as to be movable back and forth, and the front end of the valve main body 62, and the spool 26 is prevented from coming out of the valve main body 62. As an urging member that is disposed between the end plate 64 for preventing prevention and between the end plate 64 and the front end of the spool 26 and urges the spool 26 toward the solenoid portion 11 with a predetermined spring load. A spring 44 is provided.

  The spool 26 is formed at the front end, and is formed with a spring seat 60 inserted into the spring 44, a large-diameter land 66 formed adjacent to the rear of the spring seat 60, and adjacent to the rear of the land 66. A small-diameter groove 67, a large-diameter land 68 formed adjacent to the rear of the groove 67, a small-diameter groove 69 formed adjacent to the rear of the land 68, and adjacent to the rear of the groove 69. And a small-diameter plunger abutting portion 72 formed adjacent to the rear of the land 71.

  The valve body 62 includes an input port p1 to which an input pressure supplied from a modulator valve (not shown) is supplied, an output port p2 for outputting an output pressure to the control valve, a sealed feedback port p3, and a drain port p4. The feedback port p3 is communicated with the output port p2 via a feedback oil passage (not shown), and the output pressure is supplied as a feedback pressure to generate an urging force corresponding to the area difference between the lands 68 and 71. The spool 26 is urged forward by the urging force. A notch k is formed in the input port p1.

  Therefore, the spool 26 receives the thrust force from the plunger 14, the spring load of the spring 44, and the feedback force due to the feedback pressure, and advances and retreats integrally with the plunger 14 in a state where the plunger contact portion 72 is in contact with the plunger 14. Be made.

  Thus, since the plunger 14 is directly supported by the cylindrical part 51 and the end parts 58 and 59, it is not necessary to arrange | position a stator core radially inward from the coil 17 like the past. Therefore, not only can the solenoid unit 11 be reduced in size, but also the number of windings 16 can be increased and the magnetomotive force can be increased.

  Further, since the coating layer 70 is formed on the outer side in the radial direction of the base 83, not only the friction coefficient μ can be reduced, but also the frictional resistance Fr can be reduced.

  By the way, as shown in FIG. 4, when the blending ratio of the fluororesin to nickel phosphide is changed between 0 to 35 [%], the friction coefficient μ of the coating layer 70 changes in proportion to the blending ratio. However, the lower the blending ratio, the larger, and the higher the blending ratio, the smaller. On the other hand, the frictional resistance Fr of the coating layer 70 increases as the blending ratio decreases and decreases as the blending ratio increases. However, if the blending ratio is 0% or more and lower than 15%, the blending ratio The amount of change in the frictional resistance Fr when changing the mixing ratio is small, and when the mixing ratio is 15% or more and lower than 30%, the amount of change in the frictional resistance Fr when changing the mixing ratio is When it is large and the blending ratio is 30% or more, the amount of change in the frictional resistance Fr when the blending ratio is changed is small.

  Therefore, in the present embodiment, the blending ratio is set to 30% or more.

  Therefore, sliding between the plunger 14 and the yoke 34 is made good, the plunger 14 can be smoothly advanced and retracted, and the hydraulic pressure can be adjusted with high accuracy by the pressure regulating valve portion 12, so that the linear solenoid valve Ten characteristics can be improved.

  Next, the operation of the linear solenoid valve 10 having the above configuration will be described.

  In the initial position of the plunger 14, when the contact portion 27 is brought into contact with the bottom portion 56 and current is supplied to the coil 17 through the terminal tm, magnetic flux is generated, but the bobbin 15 is formed of a nonmagnetic material. As a result, the current bypasses the bobbin 15 and forms a magnetic path from the outer yoke 20 through the end portion 58, the plunger 14 and the end portion 59 to the outer yoke 20 in this order. A suction part is formed between the edge 61 and the plunger 14 in the path.

  In this case, a gap is formed between the rear end surface of the plunger 14 and the outer yoke 20 as much as the contact portion 27 is formed, and the surface of the contact portion 27 is formed as described above. Since the surface treatment is performed and the coating layer 70 made of a nonmagnetic material is formed, the magnetic flux does not leak from the rear end of the plunger 14. Further, since the gap between the inner peripheral surface of the end portions 58 and 59 and the outer peripheral surface of the plunger 14 is made sufficiently small, the magnetic resistance of the magnetic path can be reduced.

  The coil 17 sucks the plunger 14 with a predetermined suction force and causes the plunger 14 to generate a thrust. As a result, the thrust is transmitted to the spool 26 together with the feedback pressure against the spring load by the spring 44, the pressure regulating valve portion 12 is operated, and the spool 26 moves forward (moves leftward in FIG. 1). It is done. In this case, based on the stroke amount of the plunger 14, the spool 26 is advanced integrally with the plunger 14 against the spring load, and the position of the spool 26 is controlled. Thereby, the distribution ratio between the input port p1 and the drain port p4 is controlled, the hydraulic pressure is linearly adjusted, and the adjusted hydraulic pressure is output as the output pressure from the output port p2.

  By the way, in the said attraction | suction part, the edge part 61 is formed in a taper toward back, and the cross-sectional area of a magnetic path is made small in the edge part 61. FIG. Therefore, magnetic saturation occurs at the edge 61 in accordance with the value of the current supplied to the coil 17, that is, the current value and the stroke amount of the plunger 14. As a result, the suction force with respect to the stroke amount of the plunger 14 at each current value becomes relatively flat.

  Further, in the axial direction, the plunger 14 and the end portion 59 always overlap each other, and a predetermined magnetic flux delivery portion is secured. If the cross-sectional areas of the magnetic flux passages of the plunger 14 and the outer yoke 20 are both substantially constant, the amount of overlap between the end portion 58 and the plunger 14 is greater than or equal to the above-mentioned magnetic flux passage cross-section area regardless of the stroke of the plunger 14. By setting, not only can the solenoid 51 be downsized, but also the magnetic efficiency can be improved.

  When the supply of current to the coil 17 is cut off, the spool 26 and the plunger 14 are retracted (moved rightward in FIG. 1) by the spring load. Accordingly, the contact portion 27 collides with the bottom portion 56. At this time, the abutting portion 27 has a convex shape, and the outer yoke 20 is made of a relatively soft metal such as low carbon steel and is formed by plastic metal processing such as cold forging. The impact is reduced and the plunger 14 quickly returns to the initial position.

  In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

It is sectional drawing of the linear solenoid valve in embodiment of this invention. It is sectional drawing of the conventional linear solenoid valve. It is sectional drawing of the plunger in embodiment of this invention. It is a relationship figure of the compounding rate of a fluororesin in the embodiment of the invention, and the characteristic of a plunger.

Explanation of symbols

14 Plunger 15 Bobbin 16 Winding 17 Coil 18, 19 End portion 20 Outer yoke 22 Hollow portion 34 Inner yoke 62 Valve body 70 Covering layer

Claims (5)

  A coil formed by winding a winding around a non-magnetic material, an end portion that is disposed adjacent to the coil and that surrounds the coil and the end portion, and is magnetically disposed. And a plunger disposed slidably with respect to the inner peripheral wall of the hollow portion formed radially inward of the non-magnetic body and the end portion. And a coating layer formed on an outer peripheral wall of the base, the coating layer being formed by dispersing and eutecting a fluororesin in nickel phosphide.   The solenoid drive device according to claim 1, wherein the fluororesin is polytetrafluoroethylene.   The solenoid drive device according to claim 1, wherein a blending ratio of the fluororesin is set to 30% or more by mass percentage.   The solenoid driving device according to claim 1, wherein a nitrided layer formed by gas soft nitriding is formed on an inner peripheral wall of the hollow portion.   A coil formed by winding a winding around a non-magnetic material, an end portion that is disposed adjacent to the coil and that surrounds the coil and the end portion, and is magnetically disposed. A yoke composed of a body, a plunger slidably disposed with respect to the inner peripheral wall of the hollow portion formed radially inward of the non-magnetic body and the end portion, and the yoke being assembled integrally The plunger includes a base made of a magnetic material and a coating layer formed on the outer peripheral wall of the base, and the coating layer is obtained by dispersing and eutecting a fluororesin on nickel phosphide. A solenoid valve formed.

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