JP2006012727A - Proximity switch and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proximity switch of high reliability and its manufacturing method with uncomplicated manufacturing processes and free from crack of resin after manufacturing. <P>SOLUTION: The proximity switch is provided with a reed switch 1, the surrounding of which is integrally molded with a resin part B, and the reed switch 1 is supported by a resin block 10. The manufacturing method of the proximity switch is a method of filling filler resin in a molding die and integrally molding the surrounding of the reed switch 1 with the resin part B, in which, after the resin block 10 is arranged inside the molding die and the reed switch 1 is made supported by the resin block 10, the filler resin is filled in the molding die to mold the resin part B. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a proximity switch that can detect that an object is approaching in a non-contact state and a manufacturing method thereof.

  Conventional proximity switches have been used, for example, to detect opening / closing of a lid or the like and to be used as a sensor for measuring the flow rate of gas or liquid. It operates by a combination of a permanent magnet and a proximity switch, but the permanent magnet is installed on the object to be detected or linked to the object to be detected, and the reed switch in the proximity switch by the magnetic attraction force when the permanent magnet approaches It is made to detect by operating. This type of proximity switch uses a reed switch in which a lead wire made of a ferromagnetic material is placed oppositely and enclosed in a glass tube, and is housed in a resin-molded case so that it can be easily applied to various application products. .

  When the proximity switch is brought close to the permanent magnet, the contact portion disposed oppositely in the glass tube of the reed switch comes into contact with the magnetic attraction force of the permanent magnet, and the proximity switch is turned on. On the other hand, when the proximity switch is separated from the permanent magnet, the action of the magnetic attractive force is lost, the contact portion is opened by the elasticity of the lead piece, and the proximity switch is turned off.

  For example, such a proximity switch is formed by molding a plurality of resins around the glass tube of the reed switch in some cases, and is integrally formed by resin transfer molding after the reed switch is mounted on a substrate. The reed switch is fixed at a predetermined position by mounting the reed switch on the substrate. In addition, the lead wires connected to both terminals of the reed switch are drawn to the outside of the proximity switch, facilitating electrical connection with external devices when the proximity switch is used in various devices (for example, Patent Document 1).

JP 2003-203536 A (page 1-2, FIG. 1)

  The conventional proximity switch requires complicated processes such as molding the periphery of the glass tube of the reed switch with a plurality of resins and mounting the reed switch on a substrate. In addition, a board such as a printed circuit board on which a reed switch is mounted has complicated deformation and expansion / contraction due to heat, causing distortion at the boundary surface with the surrounding filling resin and causing cracks in the resin. There is a problem that the reliability of the proximity switch is lowered.

  The present invention has been made to solve the above-described problems, and provides a highly reliable proximity switch that does not require complicated manufacturing processes and does not cause resin cracks after manufacturing, and a method for manufacturing the proximity switch. For the purpose.

The present invention is a proximity switch that includes a reed switch and is integrally molded with a resin portion around the reed switch, and the reed switch is supported by a resin block.
Moreover, a lead wire is attached to each terminal portion of the reed switch to form a connection portion, and the connection portion is supported by a resin block.

Further, the connection part of the reed switch is supported by the fitting part of the resin block.
Further, the connection part of the reed switch is supported by the V-shaped part of the resin block.
Further, the resin block is constituted by a flat portion and a standing portion, and a support portion for the connection portion is provided at the tip of the standing portion.

Moreover, a part of resin block comprises a part of resin part surface.
Further, all of the resin block is taken into the resin portion.
The resin portion around the reed switch is made of a thermoplastic material.

The present invention relates to a method for manufacturing a proximity switch in which a molding resin is filled with a filling resin and the periphery of the reed switch is integrally molded by a resin portion. After being supported by the resin block, the resin part is molded by filling the molding die with a filling resin.
In addition, after filling a part of the molding die with a filling resin to form a resin block, the resin part is filled with another filling resin.

Furthermore, after the reed switch is supported by a magnetic attractive force, the resin portion is molded by filling a filling resin.
The reed switch is supported by passing a magnetic flux perpendicular to the reed switch axis through the center of the contact.
Further, the filling resin for forming the resin portion is made of a thermoplastic material.

  According to the proximity switch and the method for manufacturing the same according to the present invention, the manufacturing method is not complicated, the resin is not cracked after the manufacturing, and the reliability is high.

[Embodiment 1]
1 is a longitudinal sectional view of a proximity switch according to Embodiment 1 of the present invention, and FIG. 2 is a sectional view of FIG. 1 taken along the line II. First and second terminals 2 and 3 are provided at both ends of the reed switch 1 in the axial direction, and the first terminal 2 is soldered to the end of the first lead wire 4 bent into a square shape. The end of the second lead wire 5 is soldered to the second terminal 3, and the first and second lead wires 4 and 5 are connected to the shaft of the reed switch 1 on the second terminal 3 side. The reed switch assembly A is mounted substantially parallel to the direction. The first terminal 2 and the first lead wire 4, and the second terminal 3 and the second lead wire 5 are connected in the same direction, and the first connection portion 6 and the second connection portion 7 are connected. Is forming.

  The resin block 10 is formed integrally with, for example, a thermosetting resin, and includes a bottom surface portion 10a on a plane, and first and second support portions 10b provided upright along a side edge portion thereof. 10c. First and second tip recesses 11a and 11b are provided at the tip portions of the first and second support portions 10b and 10c, and the first and second connections of the reed switch 1 are provided in the recesses 11a and 11b, respectively. The parts 6 and 7 are pushed in and fitted.

  The position above the bottom surface of the bottom surface portion 10a of the resin block 10 is covered with, for example, a thermoplastic filling resin to form the resin portion B, and the other portions excluding the bottom surface of the bottom surface portion 10a of the resin block 10, the reed switch 1, And the vicinity of the connecting portion between the first and second lead wires 4 and 5 is embedded and fixed at a predetermined position. The first and second lead wires 4 and 5 are drawn from the first terminal portion 3 side to the outside of the proximity switch.

FIG. 3 is an explanatory view showing a manufacturing method of the proximity switch shown in FIGS. As shown in FIG. 3 (a), a lower molding die 30 for molding a proximity switch has a U-shaped cross section composed of a bottom portion 30a and a standing portion 30b, and positioning pins 32a, 32b is erected, and a resin injection part 31 is formed in the erected part 30b.
As shown in FIG. 3B, a hole (not shown) of the resin block 10 molded in advance is inserted into the positioning pins 32a and 32b of the lower molded metal fitting 30, and the bottom surface 10a of the resin block 10 is inserted. Is brought into contact with the bottom 30 a of the lower molding die 30.

  Before the above process or after the above process, the end portion of the first lead wire 4 is soldered to the first terminal 2 of the reed switch 1 to form the first connection portion 6. The end of the second lead wire 5 is soldered to the second terminal 3 to form the second connection portion 7, and these lead wires 4 and 5 are in the axial direction of the reed switch 1 on the second terminal 3 side. To form a reed switch assembly A.

As shown in FIG. 3C, the first and second connection portions 6 and 7 of the reed switch 1 are connected to the first and second tip recesses 11a and 11b of the first and second support portions 10b and 10c. The reed switch assembly A is held at the tip of the resin block 10.
As shown in FIG. 3D, the upper molding die 40 is overlaid on the lower molding die 30 to provide an integrally molded hollow portion 50 in the die, and the reed switch assembly A and the resin block 10 are attached. Seal.
As shown in FIG. 3 (e), after filling resin is injected into the integrally formed hollow portion 50 from the resin injection portion 31 of the lower molding fitting 30, and the resin portion B is formed by heating and curing, the upper molding die is formed. 40 and the lower mold 30 are separated, and the proximity switch is taken out.

  In the above description, a case where a thermosetting resin is used for molding the resin block 10 and a thermoplastic resin is used for molding the filling portion B of the proximity switch is shown. However, when the resin portion B is molded integrally, The resin block 10 is not limited to the above resin as long as the resin block 10 does not significantly soften or dissolve and satisfies various characteristics required for the proximity switch. Further, in the above description, the mold has been described as separating the upper and lower parts, but by forming the tip recesses 11a and 11b of the resin block 10 in an appropriate shape, the mold can be separated into left and right. (The same applies to the following embodiments).

  According to the proximity switch according to the first embodiment, the inside of the resin portion B integrally formed with the filling resin includes the reed switch assembly A in which the first and second lead wires 4 and 5 are soldered, Since the reed switch assembly A is constituted by the resin block 10 that holds the lead recesses 11a and 11b, the manufacturing cost of the proximity switch can be reduced without using an expensive substrate. In addition, since a composite material of glass fiber and resin typified by a printed circuit board is not used, a difference in thermal expansion between the substrate and the resin part B due to a change in the external temperature environment does not occur, which may cause a resin crack. A highly reliable proximity switch can be obtained.

  Further, according to the above proximity switch manufacturing method, the reed switch assembly A is pushed and held in the tip recesses 11a and 11b of the resin block 10, and then the filling resin is injected. Even if pressure is applied, the installation position of the reed switch assembly A does not change in the integrally formed hollow portion 50. Therefore, the reed switch assembly A can be reliably arranged at a predetermined position in the proximity switch, and a proximity switch excellent in detection distance stability can be obtained.

[Embodiment 2]
FIG. 4 is an explanatory view showing a manufacturing method of the proximity switch according to the second embodiment of the present invention, and shows a case where the same proximity switch as shown in the first embodiment is manufactured by a method different from the first embodiment. ing. In the first embodiment, the resin block 10 that has already been molded is attached to the lower molding die 30 and then the proximity switch is integrally molded. In the second embodiment, the resin is molded by the molding die. The block is formed, and subsequently, the proximity switch is integrally formed.

As shown in FIG. 4 (a), a lower molding fitting 30 for molding a proximity switch has a substantially U-shaped cross section composed of a bottom portion 30a and an upright portion 30b, and a positioning pin 32a, 32b is erected.
As shown in FIG. 4B, a resin block molding die 60 is overlaid on the lower molding die 30. The resin block molding die 60 is provided with a resin block molding hollow portion 61 for injecting a filling resin for molding the resin block 10. The resin block molding hollow portion 61 communicates with the resin block molding hollow portion 61. A part 62 is provided.
As shown in FIG. 4 (c), the resin block 10 is molded by injecting a filling resin from the resin injection part 62 of the resin block molding die 60 into the resin block molding hollow part 61.
After the resin block 10 is molded, the resin block molding die 60 is removed as shown in FIG.

  Prior to the above process or after the above process, the end of the first lead wire 4 is soldered to the first terminal 2 of the reed switch 1, and the end of the second lead wire 5 is connected to the second terminal. The lead switch assembly A is formed so that these lead wires 4 and 5 are substantially parallel to the axial direction of the reed switch 1 on the second terminal 3 side.

As shown in FIG. 4 (e), the first and second connecting portions 6 and 7 of the reed switch assembly A are pushed into the tip recesses 11 a and 11 b of the resin block 10, and the reed switch assembly A is moved to the resin block 10. Support at the tip.
As shown in FIG. 4 (f), the upper molding die 40 having the resin injection portion 41 is aligned with the lower molding die 30 to provide an integrally molded hollow portion 50.
As shown in FIG. 4G, the filling resin is injected from the resin injection portion 41 of the upper molding die 40 to fill the integral molding hollow portion 50. After the filling resin is heated and cured to form the resin part B, the upper molding die 40 and the lower molding die 30 are separated, and the proximity switch is taken out.

  According to the above proximity switch manufacturing method, the lower molding die 30 used for integrally molding the proximity switch is used for molding the resin block 10 for fixing the reed switch assembly A in the proximity switch. Therefore, the molding of the resin block 10 and the integral molding of the proximity switch can be performed continuously in a series of steps, and the manufacturing cost of the proximity switch can be reduced.

[Embodiment 3]
5 is a longitudinal sectional view of a proximity switch according to Embodiment 3 of the present invention, and FIG. 6 is a sectional view of FIG. 5 taken along a roll line. In the first embodiment, in the resin part B, the other part excluding the bottom surface of the bottom surface part 10a of the resin block 10, the reed switch 1, and the first and second lead wires 4 and 5 are embedded to constitute a proximity switch. However, in the third embodiment, the entire resin block 10 is embedded in the resin portion B to constitute a proximity switch. That is, the resin block 10 is made smaller than the case shown in the first embodiment, and the entire periphery is covered with the filling portion B.

  According to the third embodiment, the same effect as that shown in the first embodiment is obtained. Furthermore, since the resin block 10 is made smaller and embedded in the resin part B of the proximity switch, a part of the resin block 10 does not constitute a part of the resin part surface as in the first embodiment. The mechanical strength of the proximity switch can be improved. Moreover, since the resin block 10 was reduced in size, the material which shape | molds the resin block 10 can be decreased, and cost can be reduced.

[Embodiment 4]
FIG. 7 is a longitudinal sectional view of a proximity switch according to Embodiment 4 of the present invention, and FIG. 8 is a sectional view of FIG. 7 taken along a ha-ha line. In the first embodiment, the case where the first and second connecting portions 6 and 7 of the reed switch assembly A are pushed into the tip recesses 11a and 11b of the resin block 10 has been shown. In the fourth embodiment, The tip recesses 11a and 11b of the resin block 10 are formed wider than the first and second connection portions 6 and 7 of the reed switch 1 so that these connection portions 6 and 7 can be easily supported without being pushed in. is there.

As shown in FIG. 8, the tip recesses 11a and 11b of the resin block 10 have a substantially V-shaped cross section that widens toward the end side, and the V-shaped portion includes first and second reed switch assemblies A. Two connecting portions 6 and 7 are placed. In this case, a magnet is attached to the bottom of the lower molding die used in the manufacturing process of the proximity switch, the reed switch assembly A is held by magnetic attraction, and the filling resin is injected. (See below). At this time, the position of the reed switch is fixed when magnetic flux in a direction perpendicular to the reed switch axis passes through the contact center.
Other configurations and effects are substantially the same as those in the case of the first embodiment, and thus description thereof is omitted.

  FIG. 9 is an explanatory view showing a method of manufacturing a proximity switch according to the fourth embodiment, and FIG. 10 is an explanatory view of a state where FIG. 9 is cut by a knee line. As shown in FIGS. 9 and 10, the resin block 10 is fitted into the positioning pins 32 a and 32 b of the lower molding fitting 30 through the holes of the resin block 10, and is arranged in the lower molding die 30.

Next, the first and second connection portions 6 and 7 of the reed switch assembly A are placed on the V-shaped portions of the tip recesses 11 a and 11 b of the resin block 10. At this time, the magnet 70 is attached to the bottom 30a of the lower molded metal fitting 30 so that the magnetic flux 71 from, for example, the N pole in the direction perpendicular to the axis of the reed switch 1 passes through the contact center of the reed switch 1. It has been. In this state, the filling resin is injected and cured by heating. During this time, the reed switch assembly A can be fixed so as not to move from the resin block 10 without closing the contact of the reed switch 1.
Since other operations are substantially the same as those shown in the first embodiment, the description thereof is omitted.

  In the above description, the magnet 70 is used to fix the reed switch 1 in a predetermined position, but other means may be used as long as the reed switch 1 can be magnetically fixed. Also, the case where the magnetic flux in the direction perpendicular to the axis of the reed switch 1 passes through the center of the contact of the reed switch 1 and the contact does not close is shown. However, when the molding temperature at the time of integral molding is sufficiently low, the contact is closed. It is also possible to perform integral molding in the state of being.

  According to the fourth embodiment, the same effect as that shown in the first embodiment is obtained. Furthermore, the tip recesses 11a and 11b of the resin block 10 are made wider than the widths of the first and second connection portions 6 and 7, and the reed switch 1 can be magnetically attracted to the lower molding die 30. A magnet 70 is arranged. For this reason, it is not necessary to push the reed switch assembly A into the resin block 10, and it is possible to prevent an excessive force from being applied to the first and second terminals 2 and 3 and Since the reed switch assembly A is not displaced even at the time of injection, a proximity switch with high reliability and excellent detection distance stability can be obtained.

It is a longitudinal cross-sectional view of the proximity switch which concerns on Embodiment 1 of this invention. It is sectional drawing of the state which cut | disconnected FIG. 1 by the II line. 6 is an explanatory diagram illustrating a method for manufacturing the proximity switch according to Embodiment 1. FIG. It is explanatory drawing which shows the manufacturing method of the proximity switch which concerns on Embodiment 2 of this invention. It is a longitudinal cross-sectional view of the proximity switch which concerns on Embodiment 3 of this invention. It is sectional drawing of the state which cut | disconnected FIG. 5 by the roll line. It is a longitudinal cross-sectional view of the proximity switch which concerns on Embodiment 4 of this invention. It is sectional drawing of the state which cut | disconnected FIG. 7 with the ha ha line. 10 is an explanatory view showing a method for manufacturing a proximity switch according to Embodiment 4. FIG. It is explanatory drawing which shows the manufacturing method of the proximity switch of the state which cut | disconnected FIG. 9 with the knee line | wire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reed switch 2,3 1st, 2nd terminal 4,5 1st, 2nd lead wire 6,7 1st, 2nd connection part 10 Resin block 10a Bottom face part 10b, 10c 1st, 2nd Support portions 11a, 11b First and second tip recesses 30 Lower molding die 40 Upper molding die 60 Molding die for resin block 70 Magnet A Reed switch assembly B Resin portion

Claims (13)

  A proximity switch comprising a reed switch and integrally formed with a resin portion around the reed switch, wherein the reed switch is supported by a resin block.   The proximity switch according to claim 1, wherein a lead wire is attached to each terminal portion of the reed switch to form a connection portion, and the connection portion is supported by the resin block.   The proximity switch according to claim 2, wherein a connecting portion of the reed switch is supported by a fitting portion of the resin block.   The proximity switch according to claim 2, wherein a connecting portion of the reed switch is supported by a V-shaped portion of the resin block.   5. The proximity switch according to claim 1, wherein the resin block includes a flat portion and a standing portion, and a support portion for the connection portion is provided at a tip of the standing portion.   6. The proximity switch according to claim 1, wherein a part of the resin block constitutes a part of the surface of the resin part.   6. The proximity switch according to claim 1, wherein all of the resin block is taken in the resin portion.   The proximity switch according to claim 1, wherein a resin portion around the reed switch is made of a thermoplastic material.   In a manufacturing method of a proximity switch in which a molding resin is filled with a filling resin and the periphery of the reed switch is integrally molded with a resin portion, a resin block is disposed in the molding die and the reed switch is supported by the resin block Then, a resin part is molded by filling the molding die with a filling resin, and the method for manufacturing a proximity switch is characterized by the following.   10. The proximity switch manufacturing method according to claim 9, wherein a resin block is formed by filling a part of the molding die with a filling resin, and then filling another filling resin to form a resin part. Method.   The method of manufacturing a proximity switch according to claim 9 or 10, wherein after the reed switch is supported by a magnetic attractive force, a resin portion is formed by filling a filling resin.   12. The proximity switch manufacturing method according to claim 11, wherein a magnetic flux in a direction perpendicular to the axis of the reed switch is passed through a contact center to support the reed switch.   The method for manufacturing a proximity switch according to claim 9, wherein the filling resin for forming the resin portion is made of a thermoplastic material.

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