JP4579339B2 - Manufacturing method of solenoid valve - Google Patents

Description

  The present invention relates to an oil control valve (hereinafter referred to as “OCV”) that controls the supply amount of fluid such as oil to a valve timing adjusting device that controls the opening and closing timing of intake valves and exhaust valves of an internal combustion engine (hereinafter referred to as “engine”). And so on).

  A conventional solenoid valve includes a valve portion in which a spool is slidably disposed in a housing having a plurality of fluid ports, and a shaft that contacts the spool of the valve portion and is movable with the spool. And a solenoid part that slides in the direction. Here, the solenoid part has a coil for generating electromagnetic force and a substantially cylindrical bobbin for winding the coil. A through hole is formed in the center of the bobbin, and two stators that normally constitute a magnetic circuit are press-fitted or inserted from both sides in the axial direction. The bobbin has a terminal press-fitting hole that feeds power from an external power source. In many cases, the bobbin around which the coil is wound and the terminal are used as insert parts, and the outer part is integrally molded to include the connector part. And is covered with an exterior resin part.

  However, in an electromagnetic valve structured to perform exterior molding using a bobbin wound with a coil as an insert component in this way, the molding pressure at the time of exterior molding directly acts on one end surface in the axial direction of the bobbin. An axial distortion will occur. When deformation such as distortion occurs in the bobbin, cracks occur in the thin portion of the bobbin, assembly accuracy with the core and other components inserted into the bobbin deteriorates, or the coils wound around the bobbin rub against each other In addition, there is a risk of causing various inconveniences that lead to a fatal malfunction of the solenoid part, such as erroneous conduction caused by peeling off the coil coating.

  In order to avoid the inconvenience as described above, for example, a means for increasing the mechanical strength by thickening the bobbin can be considered. However, such thickening results in an increase in the size and weight of the solenoid valve as a product.

  Note that Patent Documents 1 to 3 each disclose an electromagnetic valve provided with a bobbin having a step, and a structure in which a molding pressure directly acts on any bobbin during molding.

Japanese Patent Laid-Open No. 10-266923 (FIG. 2) JP 2000-130629 A (FIG. 2) Japanese Patent Laid-Open No. 11-118063 (FIG. 1)

  The present invention was made to overcome the drawbacks of conventional solenoid valves, and the object of the present invention is to avoid an increase in bobbin thickness, which causes an increase in the size and weight of the solenoid valve, and to form an exterior. It is in providing a solenoid valve having a structure capable of preventing inconvenience such as deformation of a bobbin at the time.

A method of manufacturing an electromagnetic valve according to the present invention includes a valve portion in which a spool is slidably disposed in a housing having a plurality of fluid ports, and a shaft that contacts the spool of the valve portion and is movable with the spool. A solenoid part that slides in the axial direction of the housing, and the solenoid part includes at least a substantially cylindrical bobbin having a through hole in the center, a coil wound around an outer peripheral surface of the bobbin, and the bobbin An assembly having a cylindrical portion disposed in the through-hole and a core having a flange portion formed in the cylindrical portion, and the core projects to the opposite side of the valve portion from the flange portion. In the method of manufacturing an electromagnetic valve having a portion using at least an upper mold and a lower mold, the assembly is placed in the lower mold, and the rear surface of the core flange is the lower mold. Abuts the top surface A lower mold installation step for installing the upper mold, an upper mold installation step for placing the upper mold on the lower mold, a molding resin is injected from the gate of the upper mold, and the shaft of the bobbin is injected by the flange A resin injection step of receiving a molding pressure of the molding resin injected toward one end surface in the direction, and integrating a core and the bobbin and forming an exterior resin portion that surrounds the periphery of the coil In the valve manufacturing method, the resin injecting step injects a molding resin from between a bottom surface of the connector opening and a flange portion of the core .

According to the present invention, the solenoid unit includes a solenoid unit that abuts the spool of the valve unit and slides a shaft movable along with the spool in the axial direction of the housing, and the solenoid unit has a through hole at least in the center. A substantially cylindrical bobbin having a coil wound around the outer peripheral surface of the bobbin, a cylindrical part disposed in the through-hole of the bobbin, and a core having a flange formed in the cylindrical part. In the method for manufacturing an electromagnetic valve having at least an upper mold and a lower mold, the core has a portion protruding to the opposite side of the valve portion from the flange portion. A lower mold installation step in which the assembly is installed in a lower mold so that a rear surface of the flange portion of the core is in contact with an upper end surface of the lower mold; and an upper mold is placed on the lower mold. Mold installation step and the upper mold The molding resin is injected from the gate of the mold, the molding resin receives the molding pressure of the molding resin injected toward the one axial end surface of the bobbin by the flange portion, and the core and the bobbin are integrated and the coil And a resin injection step for forming an exterior resin portion that surrounds the periphery of the electromagnetic valve, wherein the resin injection step is for molding from between a bottom surface of the connector opening and a flange portion of the core. Since the resin is injected, the deformation of the bobbin can be surely prevented by preventing the molding pressure during the exterior molding from directly acting on the bobbin. As a result, cracks occur in the thin part of the bobbin, assembly accuracy with the core and other components inserted into the bobbin deteriorates, or the coils wound around the bobbin rub against each other and the coil coating peels off. It is possible to reliably prevent various inconveniences such as erroneous conduction. Moreover, since the bobbin can be made thicker, an increase in the size and weight of the solenoid valve can be avoided.

It is sectional drawing which shows the internal structure of the solenoid valve by Embodiment 1 of this invention. It is a top view which shows components, such as a core before exterior shaping | molding, in the solenoid valve shown in FIG. It is the III-III sectional view taken on the line of FIG. It is sectional drawing which shows structural components, such as a core at the time of exterior shaping | molding, in the solenoid valve shown in FIG.

Embodiment 1 FIG.
1 is a cross-sectional view showing the internal structure of a solenoid valve according to Embodiment 1 of the present invention, and FIG. 2 is a plan view showing components such as a core before exterior molding in the solenoid valve shown in FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2, and FIG. 4 is a cross-sectional view showing components such as a core during exterior molding in the electromagnetic valve shown in FIG. In FIG. 1, the right side is the front, the left side is the rear, and the upper side is the front and the lower side is the rear in FIGS.

  As shown in FIG. 1, the electromagnetic valve 1 is generally composed of a valve portion 3 and a solenoid portion 5 that controls opening and closing of the valve portion 3.

  The valve portion 3 has a substantially cylindrical housing 7 having a through hole 7a, and a substantially circular shape slidably disposed in the through hole 7a of the housing 7 in the axial direction (arrow A direction or arrow B direction). It is roughly composed of a columnar spool 9. A plurality (five in the first embodiment) of fluid ports 11 are formed on the outer peripheral surface of the housing 7. These fluid ports 11 include an advance hydraulic chamber (not shown), a retard hydraulic chamber (not shown) and an oil pump (not shown) or an oil pan (not shown) of a valve timing adjusting device (not shown). Connected). For this reason, the opening area of each fluid port 11 changes according to the positional relationship of the spool 9 in the housing 7, and the supply / discharge amount of fluid such as oil is controlled.

  The housing 7 has a rear end wall 7b formed at the rearmost portion of the through hole 7a. The spool 9 is always placed in the direction of arrow A between the rear end wall 7b and the rear end portion 9a of the spool 9. A biasing coil spring 13 is disposed. The rear end wall 7b is formed with a discharge port 7c that discharges back pressure generated between the rear end wall 7b and the rear end portion 9a of the spool 9 when the spool 9 moves in the arrow B direction. . Furthermore, a large-diameter base end portion 7d that can be joined to the solenoid portion 5 is formed at the foremost portion of the housing 7, and a mounting seat portion 7e is formed at the rear portion of the large-diameter base end portion 7d.

  The solenoid unit 5 is schematically configured from a coil molded body 15 and a case 17 having a protection function for the coil molded body 15 and constituting a magnetic circuit. The coil molded body 15 includes a substantially cylindrical bobbin 19, a coil 21 wound around the outer peripheral surface 19 a of the bobbin 19, a terminal 23 fixed to the bobbin 19 by press-fitting, and a substantial circuit circuit. It is generally configured by a bottom cylindrical core 25 and an exterior resin portion 27 that integrates the core 25 and the bobbin 19 together with the terminal 23.

  A through hole 29 penetrating in the axial direction is formed at the center of the bobbin 19, and a front end surface (one axial end surface) 31 extending radially outward of the bobbin 19 is formed at the foremost portion of the through hole 29. Is formed. The front end surface 31 is formed in a flat shape except for a processing portion for processing the wiring between the coil 21 and the terminal 23. A rear end portion 33 extending outward in the radial direction is formed at the rearmost portion of the through hole 29, and a concave portion 35 that is recessed inward in the radial direction and receives the exterior resin portion 27 is formed in the rear end portion 33. Is formed. Further, a concave groove 37 for making the thickness of the exterior resin portion 27 uniform is formed in the rear end portion 33 along the circumferential direction. Further, the terminal 23 and a part of the exterior resin portion 27 constitute a connector portion that performs electrical connection with an external power source (not shown) that supplies power to the solenoid portion 5.

  A bottomed cylindrical portion (cylindrical portion) 39 is formed inside the central rear portion of the core 25, and a collar portion 41 extending radially outward is formed on the outer peripheral surface 25 a of the core 25 on the front side. ing. The rear surface (outer peripheral surface) 41a of the flange portion 41 is formed flat like the front end surface 31 of the bobbin 19, and when the core 25 is press-fitted and fixed in the through hole 29 of the bobbin 19, the bobbin 19 Close contact with the front end face 31 is possible. Further, at the outer peripheral edge of the flange portion 41, a plurality of resin flows (in the first embodiment, which secures the flow of resin between the front and rear connector portions bordering the core and the coil winding portion of the bobbin during exterior molding) Three) notches 43 are formed. Further, in order to provide an O-ring for ensuring airtightness inside and outside of the solenoid part 3, a step part is formed integrally with the exterior resin part 27 on the front side end face of the flange part 41 of the core 25. Yes. Here, the outer diameter of the bottom of the notch 43, that is, the portion farthest from the outer peripheral edge of the flange 41 is set equal to or larger than the outer diameter of the front end face 31 of the bobbin 19. . For this reason, as shown in FIG. 2, the front end surface 31 of the bobbin 19 is substantially covered by the flange portion 41 of the core 25, so that the resin flow can directly act on the front end surface 31 of the bobbin 19. Absent.

  A shaft 45 is disposed in the through hole 29 of the bobbin 19 in the coil molded body 15 configured as described above. A plunger 47 as a mover is press-fitted and fixed at a predetermined position on the central outer peripheral surface of the shaft 45, and the plunger 47 has a predetermined clearance between the outer peripheral surface and the inner peripheral surface of the bottomed cylindrical portion 39 of the core 25. It is accommodated while having. The front end portion 45a and the rear end portion 45b of the shaft 45 are press-fitted and fixed at predetermined positions on the inner peripheral surface of the boss 51 disposed on the bottom side cylindrical portion 39 of the core 25 and the rear side in the through hole 29 of the bobbin 19, respectively. The bearing members 49 and 50 are slidably contacted and supported. On the outer peripheral surface of the rear end portion 45b of the shaft 45, a bearing member 50 that is in sliding contact with the inner peripheral surface of the boss 51 disposed on the rear side in the through hole 29 of the bobbin 19 is press-fitted and fixed at a predetermined position. The boss 51 is a member having a substantially H-shaped cross section, and has a magnetic attraction portion 51 a in contact with the inner peripheral surface of the through hole 29. The rear end portion 51 b of the boss 51 is press-fitted and fixed in the middle hole 53 a of a substantially disk-shaped plate 53 that partitions the valve portion 3 and the solenoid portion 5. The plate 53 is a steel plate punching member, and its peripheral portion is a boundary step between a large-diameter base end portion 7d of the housing 7 in the valve portion 3 and a rear end thin portion 17c formed at the rear end of the case 17 described later and the body portion 17a. It is sandwiched coaxially with the part. Further, the rear end portion 45b of the shaft 45 is abutted on the same axis as the front end portion 9b of the spool 9 of the valve portion 3, and only a distance corresponding to the sliding distance of the shaft 45 when the solenoid portion 5 is energized. The spool 9 can be slid.

  As shown in FIG. 1, the case 17 includes a substantially cylindrical body portion 17a, a front end thick portion 17b formed at the front end of the body portion 17a, and a rear end thin wall formed at the rear end of the body portion 17a. It is roughly composed of a portion 17c. A substantially L-shaped bracket 55 is fixed to a predetermined position on the outer peripheral surface of the body portion 17a by welding. The bracket 55 is formed with a bolt hole 55a through which a bolt (not shown) used for fixing the electromagnetic valve 1 to the engine (not shown) is inserted. The front end thick portion 17b is bent inward, and the O-ring 57 is compressed and sandwiched between the outer resin portion 27 covering the flange portion 41 of the core 25 disposed in the coil forming body 15. It has become. The rear end thin portion 17 c is bent and holds the large-diameter base end portion 7 d of the housing 7 that is supported on the coil molded body 15 via the plate 53.

Next, the operation will be described.
First, when the solenoid portion 5 of the solenoid valve 1 is not energized (when not energized), as shown in FIG. 1, the coil spring 13 causes the spool 9 in the valve portion 3 and the shaft 45 in contact therewith to be The shaft 45 is biased in the direction of the arrow A, and the shaft 45 is stopped at a position where the front end surface of the plunger 47 contacts the rear end surface of the bearing member 49. Next, when the solenoid valve 1 is energized, the plunger 47 is moved in the arrow B direction by the magnetic force generated from the coil 21. At this time, the spool 9 also operates a predetermined distance against the biasing force of the coil spring 13 through the shaft 45 to which the plunger 47 is press-fitted and fixed, thereby controlling the opening area of the fluid port 11 of the housing 7.

Next, a method for manufacturing the coil molded body 15 will be described.
First, as shown in FIGS. 2 and 3, the coil 21 is wound around the outer peripheral surface 19 a of the resin-molded bobbin 19 by a predetermined number of turns, and the core 25 is press-fitted and fixed in the through hole 29 of the bobbin 19. Next, the terminal 23 is press-fitted into the bobbin 19, the coil 21 is fixed to the terminal 23 by fusing, and the terminal 23 is bent at a predetermined position to form an assembly. Next, a molding die 63 composed of an upper die 59 and a lower die 61 is prepared, and the assembly is inserted into the lower die 61 in a state of being positioned as shown in FIG. At this time, the rear surface (outer peripheral surface) 41a of the flange portion 41 of the core 25 abuts on the front end surface (upper end surface) 61a of the lower mold 61, and the rear end surface (the other end surface in the axial direction) of the bottomed cylindrical portion 39 of the core 25. 39a abuts against the inner bottom surface 61b of the lower mold 61. Further, the front end surface 31 of the bobbin 19 and the rear surface 41a of the flange portion 41 of the core 25 in the coil molded body 15 are both formed in a flat shape and are in close contact with each other so that no gap is generated between them.

Next, the upper mold 59 is placed on the lower mold 61, and molding resin is injected from the gate 65 of the upper mold 59. The gate 65 is formed in the vicinity of the terminal 23 constituting the connector portion.
When the resin injected from the gate 65 reaches the flange 41 of the core 25 through the gap in the upper mold 59, the molding pressure acts on the flange 41. However, the molding pressure does not directly act on the front end surface 31 of the bobbin 19 that is in close contact with the rear surface 41a of the flange portion 41. Further, when the molding pressure acts on the flange portion 41, the core 25 is pressed and retracted by the molding pressure. At this time, the rear end surface 39a of the bottomed cylindrical portion 39 of the core 25 is the central inner bottom surface 61b of the lower mold 61. Strongly pressed against. Thereby, most of the molding pressure that has acted on the core 25 can be released to the lower mold 61, so that it is possible to avoid the molding pressure from acting directly on the bobbin 19.

  On the other hand, the molding resin that has reached the flange 41 passes through the plurality of notches 43 formed in the flange 41 of the core 25, bypasses the front end surface 31 and the like of the bobbin 19, and enters the lower mold 61. To the periphery of the bobbin 19 and the coil 21 to form the exterior resin portion 27. Thereby, the flow of the resin, that is, the molding pressure does not directly act on the front end surface 31 of the bobbin 19.

  As described above, according to the first embodiment, the front end surface 31 of the bobbin 19 in the coil molded body 15 and the rear surface 41a of the flange portion 41 of the core 25 are configured to be in close contact with each other. As a result, the molding pressure during exterior molding can be prevented from acting directly on the bobbin 19 and the deformation of the bobbin 19 can be reliably prevented. Generation of cracks in the thin portion of the bobbin 19, deterioration in assembly accuracy with components such as the core 25 inserted into the bobbin 19, or the coils 21 wound around the bobbin 19 rub against each other and Various inconveniences such as poor conduction caused by peeling off of the coating can be reliably prevented. Thereby, since the thickening of the bobbin 19 can be avoided, an increase in the size and weight of the electromagnetic valve 1 associated therewith can be avoided.

  According to the first embodiment, the outer diameter of the bottom of the notch 43 formed in the flange 41 of the core 25 is set equal to or larger than the outer diameter of the front end surface 31 of the bobbin 19. Therefore, not only can the molding resin flow smoothly, but also the direct action of the molding resin on the front end surface 31 of the bobbin 19 can be avoided, thereby reliably deforming the bobbin 19. There is an effect that it can be prevented.

  According to the first embodiment, of the core 25 that receives molding pressure during exterior molding, the rear surface 41a of the flange portion 41 and the rear end surface 39a of the bottomed cylindrical portion 39 are part of the lower mold 61 of the molding die 63. Since the core 25 is pressed by the molding pressure and retracted, the rear end surface 39a of the bottomed cylindrical portion 39 of the core 25 is strongly pressed against the center inner bottom surface 61b of the lower mold 61, so that the core Since the molding pressure acting on 25 can be released to the lower mold 61, it is possible to avoid the molding pressure acting directly on the bobbin 19.

  DESCRIPTION OF SYMBOLS 1 Solenoid valve, 3 Valve part, 5 Solenoid part, 7 Housing, 7a Through-hole, 7b Rear end wall, 7c Discharge port, 7d Large diameter base end part, 7e Mounting seat part, 9 Spool, 11 Fluid port, 13 Coil spring , 15 Coil molded body, 17 Case, 17a Body part, 17b Thick part before bending, 17c Thin part after folding, 19 Bobbin, 19a Outer peripheral surface, 21 Coil, 23 Terminal, 25 Core, 27 Exterior resin part, 29 Through Hole, 31 flat front end face (one axial end face), 33 rear end part, 35 concave part, 37 concave groove, 39 bottomed cylindrical part, 41 flange part, 43 notch part, 45 shaft, 47 plunger, 49, 50 Bearing member, 51 Boss, 53 Plate, 53a Middle hole, 55 Bracket, 55a Bolt hole, 57 O-ring, 59 Upper mold, 61 Lower mold, 63 Mold, 65 Gate.

Claims (1)

A valve portion in which a spool is slidably disposed in a housing having a plurality of fluid ports, and a solenoid that abuts against the spool of the valve portion and slides a shaft movable with the spool in the axial direction of the housing. The solenoid part is at least a substantially cylindrical bobbin having a through hole in the center, a coil wound around the outer peripheral surface of the bobbin, and a cylinder disposed in the through hole of the bobbin. And an assembly having a core having a flange portion formed on the cylindrical portion, and the core includes at least an electromagnetic valve having a portion protruding to the opposite side of the valve portion from the flange portion. In a method of manufacturing using an upper mold and a lower mold,
A lower mold installation step in which the assembly is installed in the lower mold so that a rear surface of the flange portion of the core is in contact with an upper end surface of the lower mold;
An upper mold installation step of placing the upper mold on the lower mold;
The molding resin is injected from the gate of the upper mold, and the core and the bobbin are integrated by receiving the molding pressure of the molding resin injected toward the one axial end surface of the bobbin by the flange. And a resin injection step of forming an exterior resin portion that sheathes the periphery of the coil,
In the resin injection step, a molding resin is injected from between the bottom surface of the connector opening and the flange portion of the core.

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