JP2006007764A - Insert molding method, insert molding apparatus and proximity sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for an insert molding capable of molding a resin in a partially thin wall with suppressing a molding defect, an insert molding apparatus and a proximity sensor. <P>SOLUTION: The method comprises the steps of starting an injection of a molten resin J into a cavity 32 of a mold 31a and 31b from a front side of a detecting coil 11 to be made thinner of at an insert member (the first step), and then advancing a compressing member 40 towards the front of the detecting coil 11 for an inserting material in the cavity 32 and moving it to this side in front of the detecting coil 11 and carrying out a resin molding (the second step). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an insert molding method, an insert molding apparatus, and an insert molding apparatus, in which a molten resin is injected into the cavity in a state where an insert product (for example, a detection coil of a proximity sensor) is disposed in the mold cavity Related proximity sensors.

  Conventionally, as shown in Patent Document 1 below, there is one in which a detection coil is electrically connected to one end portion side of a circuit board via a lead wire, and these are integrally molded by resin molding as an insert product. For example, this is formed so that the entire detection coil is covered with a molding resin in order to achieve waterproofness, and one side (detection surface) of the detection coil directed to the detection region in order to widen the detection distance is other It is necessary to mold the resin thinner than the part. With such a configuration, the detection coil and the circuit board can be integrally formed without separately providing a holder for housing the detection coil, and the number of manufacturing steps and costs can be reduced.

Here, as a method for forming an insert product, for example, there is a method described in Patent Document 2 below. FIG. 15 shows a molding die 1 used in a conventional molding method. This is because the detection coil 2 and the circuit board 3 are temporarily held and the detection coil 2 is held in the cavity 1 a of the molding die 1 while being held by the metal holding pins 4, 4, and the molten resin 5 is disposed. This is a method of injecting from the gates 6 and 6 formed in the cavity 1a and pulling out the holding pins 4 and 4 immediately before the molten resin is cured.
Japanese Utility Model Publication No. 61-167343 JP 2003-127185 A

  However, in this type of method, the gate 6 is conventionally provided on the side wall of the cavity 1a on the circuit board 3 side. Then, the injected molten resin 5 is cooled and hardened by the holding pins 4 and 4 on the way from the circuit board 3 side to the detection coil 2 side, and between the relatively narrow detection surface 2a and the side wall of the cavity 1a. The molten resin 5 did not spread, causing defective molding.

  The present invention has been completed based on the above-described circumstances, and provides an insert molding method, an insert molding device, and a proximity sensor capable of partially resin-molding while suppressing molding defects. For the purpose.

  As a means for achieving the above object, the insert molding method according to the invention of claim 1 is characterized in that a molten resin is injected into the cavity in a state where the insert is disposed in the cavity of the molding die, An insert molding method for resin molding a predetermined part thinner than other parts, the first step of injecting the molten resin from the predetermined part side of the insert part into the cavity, A second step of advancing the compression member provided to be able to advance toward the predetermined part of the insert product in the cavity to a predetermined position before the predetermined part in the middle or after the first step; It is characterized by including.

The above invention includes the following configuration A.
“With the insert placed in the cavity of the mold, molten resin is injected into the cavity, and a predetermined part of the insert is molded to a desired thickness that is thinner than other parts. An insert molding method,
The molten resin is injected between the compression member and the predetermined portion in a state in which the compression member provided so as to be able to advance and retract along the direction facing the predetermined portion of the insert product with respect to the cavity is retracted. A first step of
And a second step of causing the compression member to advance to a position before the predetermined portion corresponding to the desired thickness after the start of injection in the first step. "

  The insert molding method according to the invention of claim 2 is the method of injecting molten resin into the cavity in a state where the detection part including at least the detection coil among the components of the proximity sensor is disposed in the cavity of the molding die, An insert molding method in which the detection surface of the detection unit is molded with a resin thinner than other parts, and the molten resin is injected into the cavity from the detection surface side of the detection unit; A second step of causing the compression member provided so as to be able to advance toward the detection surface of the detection unit in the cavity to advance to a predetermined position before the detection surface during or after the first step; It is characterized by including.

The above invention includes the following configuration B.
“With the detection unit including at least the detection coil among the components of the proximity sensor being placed in the cavity of the mold, molten resin is injected into the cavity, and the detection surface of the detection unit is placed on another detection surface. An insert molding method for resin molding to a desired thickness that is thinner than the part,
The molten resin is injected between the compression member and the detection surface in a state where the compression member provided so as to be able to advance and retreat along the direction facing the detection surface of the detection unit with respect to the cavity is retracted. 1 process,
And a second step of causing the compression member to advance to a position in front of the detection surface according to the desired thickness after injecting in the first step. "

  According to a third aspect of the present invention, in the insert molding method according to the first or second aspect, prior to the first step, the other portion is provided by a holding member provided so as to be capable of moving forward and backward with respect to the inside of the cavity. It further includes a third step of holding, and a fourth step of retracting the holding member from the cavity during the advancement of the compression member in the second step.

The above invention includes the following configuration C.
“Prior to the first step, the third step of holding the other portion by a holding member provided so as to be able to advance and retreat in the cavity;
The insert molding method according to Configuration A or Configuration B, further comprising a fourth step of retracting the holding member from the cavity during the advancement of the compression member in the second step. "

  According to a fourth aspect of the present invention, in the insert molding method according to any one of the first to third aspects, at least in the second step, the first compression member is advanced until the compression member is advanced to the predetermined position. In the process, the molten resin injected into the cavity is heated.

  A fifth aspect of the present invention is the insert molding method according to any one of the first to fourth aspects, wherein the compression member is advanced while rotating in the second step.

  According to a sixth aspect of the present invention, in the insert molding method according to any one of the first to fifth aspects, the molten resin injected into the cavity is cooled by terminating heating after the second step is completed. It is characterized by making it.

  The insert molding apparatus according to the invention of claim 7 injects the molten resin into the cavity in a state where the insert product is disposed in the cavity of the mold, and a predetermined part of the insert product is introduced from another part. Is an insert molding apparatus for resin molding into a thin wall, wherein a cavity in which the insert product is disposed, a compression member provided so as to be able to advance toward the predetermined part of the insert product in the cavity, and A compression mold formed on the side wall of the cavity in the middle of the path of the compression member and having an injection port for injecting the molten resin into the cavity, and after the injection of the molten resin from the injection port is started, the compression member Drive means for advancing to a predetermined position before the predetermined part.

The above invention includes the following configuration D.
“With the insert placed in the cavity of the mold, molten resin is injected into the cavity, and a predetermined part of the insert is molded to a desired thickness that is thinner than other parts. An insert molding device for
Cavity in which the insert product is disposed, a compression member provided so as to be able to advance and retreat in a direction opposite to the predetermined portion of the insert product with respect to the cavity, and the compression member in the retracted position of the cavity And a mold having an injection port that is formed on a side wall between the insert part and the predetermined part of the insert product and injects the molten resin into the cavity.
Insert molding comprising: drive means for advancing the compression member to a position in front of the predetermined portion corresponding to the desired thickness after the injection of the molten resin from the injection port is started. apparatus. "

  According to an eighth aspect of the present invention, in the insert molding apparatus according to the seventh aspect, the compression member closes the injection port by moving while the side surface is in sliding contact with the peripheral edge of the injection port in the advancement process. It is characterized by.

  According to a ninth aspect of the present invention, in the insert molding device according to the seventh or eighth aspect, the drive means advances the compression member by hydraulic pressure.

  The invention according to claim 10 is the insert molding apparatus according to any one of claims 7 to 9, wherein the first heating means for heating the mold, the second heating means for heating the compression member, Heating control means for controlling the first heating means to perform a heating operation at a predetermined temperature and for controlling the second heating means to perform a heating operation at a temperature equal to or higher than the predetermined temperature. It is characterized by.

  The invention according to claim 11 is the insert molding apparatus according to claim 10, wherein the driving means advances the compression member while rotating the compression member.

  According to a twelfth aspect of the present invention, in the insert molding apparatus according to the tenth or eleventh aspect, the heating control unit is configured to use at least one of the first heating unit and the second heating unit of the molding die. Control is performed so that the molten resin injected into the cavity is heated at a temperature equal to or higher than the curing start temperature at which curing starts.

  According to a thirteenth aspect of the present invention, in the insert molding apparatus according to the twelfth aspect, the heating control unit controls the first heating unit to heat the mold at a temperature equal to or higher than a curing start temperature of the molten resin. In addition, the second heating unit is controlled to heat the compression member at a temperature higher than the curing start temperature.

  A fourteenth aspect of the present invention is the insert molding apparatus according to any one of the tenth to thirteenth aspects, wherein the cooling means for cooling the mold and the cooling control means for controlling the driving means to be driven or stopped. And the cooling control means controls the driving of the cooling means on the condition that the heating control means controls to stop heating the first and second heating means. It is characterized by that.

  According to a fifteenth aspect of the present invention, in the insert molding apparatus according to any one of the tenth to fourteenth aspects, the first heating means is constituted by a flow path of a heated fluid provided in the mold, and The second heating means is constituted by a heating element accommodated in the compression member, and the cooling means is constituted by a cooling fluid flow path provided in the mold.

  According to a sixteenth aspect of the present invention, in the insert molding apparatus according to the fifteenth aspect, the flow path of the heating fluid is provided in the vicinity of the end of the cavity and on the front side in the advance direction of the compression member. It is characterized by.

  According to a seventeenth aspect of the present invention, in the insert molding apparatus according to the fifteenth or sixteenth aspect, the cooling fluid flow path is provided in the vicinity of the injection port of the molding die.

  The invention according to claim 18 is the insert molding apparatus according to any one of claims 15 to 17, wherein the flow path of the heating fluid is provided on the front side in the traveling direction of the compression member with respect to the injection port. It is characterized by being.

  The proximity sensor according to the invention of claim 19 is a proximity sensor in which at least the detection coil is formed by resin molding so that the detection surface, which is one side surface of the detection coil, is thinner than other portions in the cavity of the molding die. The detection coil is arranged in the cavity of the molding die, and the injection of molten resin from the detection surface side of the detection coil is started in the cavity, and the compression member is placed on the detection surface. The detection surface is formed thinner than other portions by advancing to a predetermined position in front of the detection surface.

The above invention includes the following configuration E.
“At least the detection coil is a proximity sensor in which the detection surface, which is one side surface of the detection coil, is molded into a thinner wall than other parts by resin molding in the cavity of the mold,
In the state where the detection coil is disposed in the cavity of the mold, and the compression member provided so as to be able to advance and retreat in the direction opposite to the detection surface is retracted in the cavity. The injection of molten resin is started between the compression member and the detection surface, and the detection surface is made thinner than other portions by advancing the compression member to a position before the detection surface according to a desired thickness. Proximity sensor characterized by being molded. "

  The invention according to claim 20 is the proximity sensor according to claim 19, further comprising a circuit board electrically connected to the detection coil and integrally formed with the detection coil by the molding, and a front surface and a back surface of the circuit board. Are mounted with substantially the same amount of electronic components.

  The invention of claim 21 is the proximity sensor according to claim 19 or claim 20, wherein the molding is primary molding, and a portion other than the primary molded primary part is secondary molded by resin molding, Of the primary molded portion, a joint portion with the secondary molded secondary molded portion is formed in an uneven shape.

  According to a twenty-second aspect of the present invention, in the proximity sensor according to any one of the nineteenth to twenty-first aspects, the molding is a primary molding, and the primary molded primary part is accommodated in a cylindrical metal case. In this state, a portion other than the primary molding part is a secondary sensor that is secondary molded by resin molding, and a through hole is formed in the side wall of the metal case at a position where the molding resin is filled by the secondary molding. It is characterized by being.

  The invention of claim 23 is the proximity sensor according to claim 21 or claim 22, further comprising a circuit board electrically connected to the detection coil and integrally formed with the detection coil by the primary molding. An indicator lamp that emits light based on a predetermined detection operation is mounted on the substrate at a location covered with the secondary molding resin, and the secondary molding resin transmits light from the indicator lamp (light emitting element). It is a translucent material that can be used.

<Invention of Claims 1, 2, 7>
According to this structure, molten resin is inject | poured from the said predetermined site | part (detection surface of the said detection part) side of insert components (detection part of a proximity sensor) with respect to the cavity of a shaping die (1st process). Next, the compression member provided so as to be able to advance toward a predetermined part of the insert product in the cavity is advanced to a predetermined position before the predetermined part in the middle or after the injection of the molten resin. Is molded into a thinner wall than other parts (second step).
With such a configuration, since the molten resin is injected from the side of the predetermined part where the resin is to be thinly formed, it is possible to prevent the problem that the molten resin does not spread to the side of the predetermined part as in the prior art. Moreover, the injected resin molding is pushed into the back side in the traveling direction by the compression member, and can be filled in the entire cavity, so that molding defects can be suppressed.

<Invention of Claim 3>
According to this configuration, prior to the first step, another portion of the predetermined portion (detection unit) is held by the holding member provided to be able to advance and retreat in the cavity (third step), and the second step. The holding member is retracted from the cavity during the advancement of the compression member in the process (fourth process).
Even with such a configuration, the injected molten resin does not stay in the vicinity of the holding member but flows to the back side by the compression member, and the molten resin can be filled up to the entire insert product, thereby suppressing defective molding. it can.

<Invention of Claim 4>
According to this configuration, at least in the second step, the molten resin injected into the cavity in the first step is heated until the compression member is advanced to a predetermined position. It can be pushed into the cavity by the compression member while preventing curing, and the molten resin can be filled in the entire cavity to prevent molding defects.

<Invention of Claims 5 and 11>
According to this configuration, since the compression member is advanced while being rotated, the molten resin can be prevented from being stirred and stiffened in the cavity and cured by the rotating compression member, which causes a molding defect. Can be suppressed.

<Invention of Claim 6>
According to this configuration, since the molten resin injected into the cavity is cooled by finishing heating after the second step is completed, the molten resin can be promoted to be cooled and cured. The molding time of the insert molded product in which the insert product is integrated with the resin can be shortened.

<Invention of Claim 8>
According to this configuration, the injection member is closed by moving the compression member while the side surface is in sliding contact with the peripheral portion of the injection port in the advancement process. Accordingly, since the injection of the molten resin can be stopped by the moving operation of the compression member, it is not necessary to separately provide a configuration for injecting the molten resin.

<Invention of Claim 9>
According to this configuration, the compression member is advanced by hydraulic pressure. With such a configuration, responsiveness and movement speed control of the compression member can be accurately performed as compared with the case of using an air type. That is, the displacement of the insert product can be prevented by controlling the movement of the compression member so as not to apply a sudden pressure to the insert product.

<Invention of Claim 10>
According to this configuration, the heating control unit controls the first heating unit to perform a heating operation at a predetermined temperature, and controls the second heating unit to perform a heating operation at a temperature equal to or higher than the predetermined temperature. For this reason, the first heating means and the second heating means can be controlled to perform the heating operation by the heating control means, respectively, so that the molten resin can be prevented from being hardened and the occurrence of molding defects can be suppressed.

<Invention of Claim 12>
According to this configuration, the heating control unit heats at least one of the first heating unit and the second heating unit at a temperature equal to or higher than a curing start temperature at which the molten resin injected into the mold cavity starts curing. Therefore, the heating control means controls the heating means to heat at least one heating means at a temperature equal to or higher than the curing start temperature of the molten resin according to the types of the first and second heating means, While optimizing the heating control of the heating means, it is possible to prevent the molten resin from being hardened and to prevent molding defects from occurring.

<Invention of Claim 13>
According to this configuration, the heating control unit controls the first heating unit to heat the mold at a temperature equal to or higher than the curing start temperature of the molten resin, and the second heating unit controls the compression member to be higher than the curing start temperature. Since it is controlled to be heated at a high temperature, the molten resin is in contact with the compression member heated at a temperature higher than the curing start temperature of the resin, and is prevented from being cured in the vicinity of the compression member. Can do.

<Invention of Claim 14>
According to this configuration, the cooling control unit controls the driving of the cooling unit on condition that the heating control unit controls to stop heating the first and second heating units. When the molten resin is stopped from being heated by the first and second heating means, it is accelerated by the cooling means to lower the temperature of the mold and is cured, thereby shortening the molding time of the insert molded product. Can do.

<Invention of Claim 15>
According to this configuration, the first heating means is constituted by a flow path of the heating fluid provided in the mold, the second heating means is constituted by the heating element accommodated in the compression member, and the cooling means is the mold. Each of the heating means and the cooling means can be formed with a simple structure, and the molten resin injected into the mold can be appropriately heated or cooled. it can.

<Invention of Claim 16>
According to this configuration, since the flow path of the heating fluid is provided near the end of the cavity and on the front side in the advance direction of the compression member, the molten resin is cured by the heating fluid flowing through the flow path. The cavity can be filled while preventing this.

<Invention of Claim 17>
According to this configuration, since the flow path of the cooling fluid is provided in the vicinity of the injection port of the molding die, the molten resin injected into the cavity from the injection port of the molding die by the cooling fluid flowing through the flow channel. It is possible to promote the cooling and hardening of the mold, and it is possible to prevent the burn from being burned even if the operator touches the mold by cooling the mold.

<Invention of Claim 18>
According to this configuration, since the flow path of the heating fluid is provided on the front side in the traveling direction of the compression member with respect to the injection port, the molten resin is more compressed than the injection port by the heating fluid flowing through the flow path. It is possible to fill the cavity while heating on the far side in the direction of travel of the material while preventing curing.

<Invention of Claim 19>
By integrally forming the detection portion by the above-described forming method, parts such as a detection portion holder are not required while suppressing molding defects, and the production cost of the proximity sensor can be reduced.

<Invention of Claim 20>
According to this configuration, substantially the same amount of electronic components are mounted on the front surface and the back surface of the circuit board. Therefore, when the compression member advances in the resin molding, the flow resistance of the molten resin is substantially uniform on both the front surface and the back surface, and deformation of the circuit board can be prevented.

<Invention of Claim 21>
According to this structure, the junction part with the said secondary shaping | molding secondary shaping | molding part among the primary shaping | molding parts is formed in uneven | corrugated shape. Therefore, the creepage distance between them becomes long and the water resistance is improved.

<Invention of Claim 22>
According to this structure, the through hole is formed in the side wall of the metal case at a position where the molding resin by the secondary molding is filled. Therefore, it can be confirmed whether the resin has been filled into the metal case during the secondary molding. In addition, after molding, the secondary molding resin filling the through holes plays the role of ridges and functions as a detent for the metal case with respect to the secondary molding member.

<Invention of Claim 23>
According to this configuration, since the secondary molding resin is a translucent material that can transmit light from the indicator lamp, a predetermined detection operation can be visually recognized by the emission operation of the indicator lamp arranged on the circuit board.

<Embodiment 1>
Embodiment 1 of the present invention relates to a proximity sensor and an insert molding method and apparatus used for manufacturing the proximity sensor, and will be described below with reference to FIGS. 1 to 13.
1. Configuration of Proximity Sensor In the proximity sensor 10 of the present embodiment, an LC parallel circuit 13 including a detection coil 11 described later is oscillated by an oscillation circuit 14, and based on the change in oscillation amplitude, the proximity of a detection target and its presence / absence are detected. It is to be determined. For example, as shown in FIG. 1, the proximity sensor 10 is used to count the workpieces W that have passed through the detection area H for a plurality of metal workpieces W that are sequentially conveyed to the production line.

(1) Circuit Configuration of Proximity Sensor FIG. 2 shows a circuit configuration of the proximity sensor 10. The LC parallel circuit 13 including the detection coil 11 and the capacitor 12 generates an alternating magnetic field H (detection region H) from the detection coil 11 by being maintained in an oscillation state by the oscillation circuit 14. When the workpiece W approaches in this oscillation state, the magnetic energy of the detection coil 11 is absorbed, and the amplitude voltage of the LC parallel circuit 13 changes (for example, decreases) accordingly. For example, the oscillation state detection circuit 15 compares the amplitude voltage of the LC parallel circuit 13 with a predetermined threshold value, and performs a detection operation based on the comparison result. In the present embodiment, as the detection operation, when the amplitude voltage of the LC parallel circuit 13 exceeds a predetermined threshold value, the light emitting element 16 (light emitting diode) as the operation indicator lamp emits light and is detected via the output circuit 17. Output the signal to the outside.

(2) Structure of Proximity Sensor FIG. 3 is a sectional view showing the structure of the proximity sensor 10. The proximity sensor 10 has a cylindrical shape as a whole, and the end surface on the front end side where the detection coil 11 is arranged is a detection surface 10a directed toward the detection region H, and the cable 20 is connected from the end surface opposite to the detection surface 10a. Has been derived. Reference numeral 11 in the figure is the detection coil 11 described above, which is a disc-shaped ferrite core 21 as a whole and a coil wound around a bobbin portion formed on one end surface of the ferrite core 21 a plurality of times. And a line 22. The detection coil 11 is arranged with the one end surface around which the coil wire 22 is wound facing the detection surface 10a.

  One end surface in the longitudinal direction of the circuit board 23 having a rectangular shape as a whole is temporarily fixed to the surface of the detection coil 11 opposite to the one end surface by, for example, soldering or adhesive. The circuit board 23 is, for example, a glass epoxy board. A predetermined circuit pattern 23a is formed on both surfaces of the circuit board 23, and the capacitor 12, the oscillation circuit 14, the oscillation state detection circuit 15, the output circuit 17, and the operation indicator lamp described above. An electronic component 23b (chip component) constituting the light emitting element 16 is mounted. In the present embodiment, the circuit board 23 is devised so that the amount of mounting (including electronic components and the amount of soldering thereof) of the primary molded portion described later of the circuit board 23 is the same on the front surface and the back surface.

  The circuit pattern 23a of the circuit board 23 is electrically connected to the coil wire 22 of the detection coil 11 through a lead wire (not shown), for example. Further, the signal line 20a of the cable 20 connected to an external control device (not shown), for example, is soldered to the circuit pattern 23a on the rear end side, and each signal such as the detection signal is controlled via the cable 20. Exchanged with devices. The cable 20 has a configuration in which a plurality of signal lines are bundled with, for example, a resin outer sheath 20b.

  The entire detection coil 11 and the part of the circuit board 23 on the detection coil 11 side are covered with a resin member (hereinafter, “primary molding member 24”) whose outer shape is primarily formed into a cylindrical shape by an insert molding device 30 described later. ing. The primary molded member 24 has a cylindrical shape as a whole, and the tip end side that covers the detection coil 11 is larger in diameter than the other portions.

  Further, in the primary molded member 24, the front wall 24a serving as the detection surface 10a is formed to be thinner than other portions in order to increase the detection distance while achieving waterproofness of the detection surface 10a portion. Further, the primary molded member 24 has a rear end portion for leading out the circuit board 23 that is slightly smaller in diameter than a central portion adjacent thereto, and a plurality of protrusions 24c are formed on the outer peripheral surface of the small diameter portion 24b. It is formed over the entire circumference. The method for forming the primary molded member 24 will be described in detail later.

  Next, the small-diameter portion 24b of the primary molding member 24, the portion of the circuit board 23 that is not primary molded, and the tip of the cable 20 are also resin members (hereinafter referred to as “secondary”, the outer shape of which is also formed into a cylindrical shape. It is integrally molded so as to be covered by the molding member 25 "). Further, a cylindrical metal case 26 made of metal and having both ends opened is provided so as to cover the outer peripheral portion from the tip of the primary molding member 24 to the central portion of the secondary molding member 25. Further, in the metal case 26, as shown in FIG. 3B, a through hole 26a is formed in a wall surface facing the outer peripheral surface of the small diameter portion 24b of the primary molded member 24. The metal case 26 is attached to the primary-formed detection coil 11 and the circuit board 23 in the manufacturing process described later, and then secondary-molded.

2. Proximity Sensor Manufacturing Method A method of manufacturing the proximity sensor 10 according to the present embodiment will be described with reference to FIGS.
(1) Configuration of Insert Molding Device FIG. 4 is a schematic diagram showing the entire insert molding device 30. This is because a pair of molding dies 31 and 31 (only the lower molding die 31a is shown in the figure) in which an insert product is arranged and a cavity 32 formed by the pair of molding dies 31 and 31 are shown. The apparatus includes a molten resin supply device 33 that supplies the molten resin J, a holding pin drive mechanism 35 that moves a pair of holding pins 34 and 34, which will be described later, a hydraulic device 36, and a control device 37.

  First, the molding dies 31, 31 will be described. As shown in FIG. 4, the lower molding die 31a is formed with a cavity groove 32a having an arc-shaped cross section extending from one end side to the other end side in the longitudinal direction. The shape is divided in half along. On the closed end side of the cavity groove 32a, a holding groove 38 is formed to hold the base end portion of the circuit board 23 among the temporarily fixed detection coil 11 and circuit board 23 (each electronic component mounted). .

  Further, when the temporarily fixed detection coil 11 and the circuit board 23 are arranged, a pair of metal holding pins 34 and 34 sandwiching the detection coil 11 portion from the side are orthogonal to the longitudinal direction of the cavity groove 32a. It is slidable along the direction. These are slidably driven by the holding pin drive mechanism 35 in a direction toward and away from each other. Further, a gate (injection port) 39 through which the molten resin J supplied from the molten resin supply device 33 is injected is formed on the opening end side of each holding pin 34 in the cavity groove 32a.

  Further, a cylindrical compression member 40 having an outer shape substantially the same as the inner diameter of the cavity 32 formed by the pair of molding dies 31, 31 is provided along the longitudinal direction of the cavity 32 at the opening end of the cavity groove 32 a. And is slidable. The compression member 40 advances with respect to the cavity 32 from the opening end side to the closing end side by the hydraulic pressure by the hydraulic device 36. The hydraulic device 36 corresponds to the driving means of the present invention.

  On the other hand, as shown in FIG. 5, the upper molding die 31b is formed with a cavity groove 32b having an arc-shaped cross section extending from one end side to the other end side in the longitudinal direction. The shape is divided in half along the line. On the closed end side of the cavity groove 32b, the base end portion of the circuit board 23 of the temporarily fixed detection coil 11 and circuit board 23 (with each electronic component mounted) is vertically moved together with the holding groove 38 of the upper molding die 31b. A holding groove 42 is formed so as to be sandwiched between and held. In addition, guide grooves 41 and 41 for guiding holding pins 34 and 34 provided on the upper molding die 31a are formed at the center position in the longitudinal direction of the cavity groove 32b.

  As will be described later, the control device 37 performs drive control by supplying control signals to the molten resin supply device 33, the holding pin drive mechanism 35, and the hydraulic device 36, respectively.

(2) Manufacturing Process of Proximity Sensor First, as shown in FIG. 6A, the coil wire 22 of the detection coil 11 is electrically connected to the circuit pattern 23a of the circuit board 23, and the rear end face of the detection coil 11 and the circuit The front end of the substrate 23 is temporarily fixed by soldering, an adhesive, or the like, and is subjected to primary molding by the insert molding apparatus 30 described above as an insert product.

  More specifically, the steps shown in FIGS. 9 to 13 are performed. As shown in FIG. 9, the temporarily fixed detection coil 11 and circuit board 23 are inserted as inserts into the cavity groove 32a of the lower molding die 31a. At this time, the insert product is disposed so that the front surface of the detection coil 11 faces the front end surface of the compression member 40 in the advancing direction. Then, holding pins 34, 34 provided in the lower molding die 31 a so as to be able to advance and retract are advanced into the cavity 32 by the holding pin drive mechanism 35, and the side surfaces of the detection coil 11 are sandwiched between the holding pins 34, 34. Hold (corresponds to the “third step” of the present invention). When the upper molding die 31b is placed and fixed, the rear end portion 23c of the circuit board 23 is sandwiched between the holding grooves 38 and 42 of both molding dies. That is, the rear end portion 23c is not primarily molded.

  Next, when the insert molding device 30 is activated, as shown in FIG. 10, the molten resin supply device 33 is driven by the control device 37, and the molten resin J is cavityd through the gate 39 formed in the lower molding die 31a. 32 (corresponding to the “first step” of the present invention). Here, the molten resin J for primary molding is preferably PBT (polybutylene terephthalate), PET (polyethylene terephthalate), or the like.

  Then, when a predetermined time has elapsed after the start of the injection of the molten resin J, the hydraulic device 36 is driven by the control device 37, and the compression member 40 advances toward the front surface of the detection coil 11 as shown in FIG. Accordingly, the molten resin J staying between the compression member 40 and the detection coil 11 is pushed into the circuit board 23 side. At this time, as described above, substantially the same amount of electronic components 23b and the like are mounted on the front surface and the back surface of the front-end side portion of the circuit board 23 that is primarily molded. The flow resistance of the molten resin J toward the substrate 23 is made substantially uniform on the front surface and the back surface.

  Then, as shown in FIG. 12, the compression member 40 further advances, and the gate 39 is closed by crossing the front of the gate 39 while being in sliding contact with the peripheral edge of the opening end of the gate 39, and the molten resin J into the cavity 32. Injection is blocked. Further, the holding pin drive mechanism 35 is driven by the control device 37, and the holding pins 34, 34 holding the side surface of the detection coil 11 are retracted to a position where the front end surface is flush with the wall surface of the cavity 32 (this book). This corresponds to the “fourth step” of the invention). The above-mentioned “predetermined time from the start of injection of molten resin” is set to a time until molten resin J required for forming the primary molding member 24 is injected into the cavity 32 during this period, This is mainly determined by the amount of molten resin to be injected, the amount of molten resin J supplied from the gate 39 per unit time, and the speed of advancement of the compression member 40. Accordingly, for example, the injection amount of the resin member from the gate 39 is detected, and the compression member 40 by the hydraulic device 36 is closed so that the compression member 40 closes the gate 39 when this detection amount reaches the amount of molten resin to be injected. The advance operation may be controlled.

  Subsequently, as shown in FIG. 13, the compression member 40 is stopped in a state where the compression member 40 is advanced to a near position where a gap corresponding to a desired thickness is formed between the front surface of the detection coil 11 (“ Corresponding to “second step”). Thereby, the injected molten resin J spreads over the entire periphery of the detection surface 10a and the front end portion of the circuit board 23. Then, after the metal mold is cooled and the molten resin J is solidified, the mold is removed, thereby producing the detection coil 11 and the circuit board 23 integrated by the primary molding member 24 as shown in FIG. 6B. Is done.

  7A and 7B, the metal case 26 is fitted to the outer peripheral surface of the primary molding member 24, and the cable 20 is soldered to the circuit pattern 23a on the rear end side of the circuit board 23. . In the present embodiment, as described above, the front end side of the primary molded member 24 is slightly larger in diameter than the other parts, and the inner diameter on the front end side of the metal case 26 is correspondingly larger than the other parts. It has become. As a result, both step portions between the outer peripheral surface of the primary molding member 24 and the inner peripheral surface of the metal case 26 are locked, and the primary molding member 24 can be prevented from being displaced forward relative to the metal case 26. ing. Further, the metal case 26 can face the small-diameter portion 24b of the primary molded member 24 from the through hole 26a in this mounted state.

  Next, secondary molding is performed while injecting molten resin between the rear end portion 23 c of the circuit board 23 and the metal case 26. Here, the molten resin for secondary molding is a material having light transmittance in a solidified state, and for example, transparent PA (polyamide / nylon), polyester elastomer, and the like are desirable. As a result, as shown in FIG. 8, the small-diameter portion 24 b of the primary molding member 24, the rear end portion 23 c of the circuit board 23 and the tip portion of the cable 20 are covered, and the outer periphery is flush with the outer periphery of the metal case 26. A secondary molded member 25 is formed. Further, light from the light emitting element 16 can be visually recognized through the light transmissive secondary molding member 25.

3. Effects of Embodiment 1 (1) According to the present embodiment, injection of the molten resin J is started from the front side of the detection coil 11 to be thinned into the insert part into the cavities 32 of the molding dies 31a and 31b. 1 step). Next, the compression member 40 is advanced toward the front surface of the detection coil 11 as an insert product in the cavity 32 and is moved to the front side of the detection coil 11 to perform resin molding (second step). Thereby, the problem that the molten resin J does not spread to the detection coil 11 side like the conventional one can be prevented. Further, the injected molten resin J is pushed into the back side in the traveling direction by the compression member 40 and can be filled in the entire cavity 32, so that molding defects can be suppressed.

(2) Prior to the first step, the side surface of the detection coil 11 is held by holding pins 34, 34 provided so as to be able to advance and retreat in the cavity 32 (third step), and the compression member in the second step During the advancement of 40, the holding pins 34, 34 are retracted from the cavity 32 (fourth step). Thereby, the injected molten resin J does not stay in the vicinity of the holding pins 34, 34 but flows to the back side by the compression member 40, so that the entire insert product can be filled with the molten resin J, and molding defects can be suppressed. it can.
(3) Further, the gate 39 is closed as the compression member 40 moves while the side surface is in sliding contact with the peripheral edge of the opening of the gate 39 in the advancement process. Thereby, since the injection of the molten resin J can be stopped by the moving operation of the compression member 40, it is not necessary to separately provide a configuration for injecting the molten resin J.

(4) Further, the compression member 40 is advanced by the hydraulic pressure of the hydraulic device 36. With such a configuration, responsiveness and movement speed control of the compression member can be accurately performed as compared with the case of using an air type. That is, the displacement of the insert product can be prevented by controlling the movement of the compression member 40 so as not to apply a sudden pressure to the insert product.
(5) If the proximity sensor 10 is manufactured by the above-described molding method, parts such as the detection unit holder are not required while suppressing molding defects, and the production cost of the proximity sensor 10 can be reduced.

(6) On the front and back surfaces of the circuit board 23, substantially the same amount of electronic components 23b and the like are mounted. Therefore, when the compression member 40 advances in the resin molding, the flow resistance of the molten resin J becomes substantially uniform on both the front surface and the back surface, and deformation of the circuit board 23 can be prevented.
(7) Of the primary molded member 24, a joint portion with the secondary molded member 25 is formed into a protrusion 24c (uneven shape). Therefore, the creepage distance between them becomes long and the water resistance is improved.

(8) Furthermore, a through hole 26a is formed in the side wall of the metal case 26 at a position where a molding resin by secondary molding is filled. Therefore, it can be confirmed whether or not the secondary molding resin is filled into the metal case 26 during the secondary molding. In addition, after molding, the secondary molding resin that fills the through hole 26 a serves as a locking projection, and functions as a detent for the metal case 26 relative to the secondary molding member 25.
(9) Further, since the secondary molding resin is a translucent material that can transmit light from the indicator lamp (light emitting element 16), predetermined detection is performed by the operation of the operation indicator lamp disposed on the circuit board 23. You can see the movement.

<Embodiment 2>
A second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the molding die 31 and the molten resin J are heated or cooled (corresponding to the inventions of claims 4, 6, 10, 12 to 18), and the compression member 40 is advanced while rotating (claim). (Corresponding to the inventions 5 and 11) is different from the first embodiment, and the other matters are the same as in the first embodiment. Therefore, the same configurations and manufacturing methods as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Only matters different from those of the first embodiment will be described.

1. Proximity Sensor Manufacturing Method (1) Configuration of Insert Molding Device FIG. 16 is a schematic diagram showing the entire insert molding device 30A of the present embodiment. Unlike the first embodiment, the insert molding device 30 </ b> A is configured by adding a power supply device 50, a hot water supply device 60, and a cooling water supply device 70.

  The lower molding die 31 a is provided with a plurality of hot water flow paths 65 in the longitudinal direction of the cavity 32 as shown in the figure. In the present embodiment, the hot water flows through the six flow paths 65 and heats the molten resin J injected into the cavity 32. The warm water is sent out to the flow path 65 by the warm water supply device 60.

  The lower molding die 31 a is provided with a cooling water flow path 75. As shown in the drawing, the cooling water flow path 75 has a gate 39 for cooling the mold 31 a and cooling the molten resin J injected into the cavity 32 so as to be integrated with the detection coil 11 and the circuit board 23. It is provided in the vicinity. In the present embodiment, the cooling water is sent out by the cooling water supply device 70 and flows through the two flow paths 75.

  As can be understood from FIGS. 16, 18 to 22, the compression member 40 operates a hydraulic cylinder (not shown) of the hydraulic device 36 by hydraulic pressure, and from the opening end side to the closing end side with respect to the cavity 32. It has come to advance towards. The compression member 40 can also be rotated by a hydraulic motor (not shown) of the hydraulic device 36. The compression member 40 rotates about its central axis as a rotation center.

  The compression member 40 accommodates a rod-shaped heater 45 as shown in the figure. The rod heater 45 is energized by being supplied with electric power by the power supply device 50. The bar heater 45 increases in temperature when energized and heats the compression member 40. The rod heater 45 corresponds to the second heating means of the present invention.

  As shown in FIG. 17, the upper molding die 31 b is provided with a hot water flow channel 66. When the lower molding die 31a and the upper molding die 31b are matched with each other, the flow channel 66 communicates with the hot water flow channel 65 provided in the mold 31a and is sent out from the hot water supply device 60. Circulate hot water. As shown in the figure, the hot water flow paths 65 and 66 are provided in the vicinity of the end of the cavity 32 and on the front side in the advancing direction of the compression member 40. The flow paths 65 and 66 are provided in front of the gate 39 in the traveling direction of the compression member 40. The hot water channels 65 and 66 correspond to the first heating means of the present invention.

  A cooling water flow path 76 is provided in the upper molding die 31b. When the lower molding die 31a and the upper molding die 31b are matched with each other, the flow channel 76 communicates with a cooling water flow channel 75 provided in the mold 31a, and from the cooling water supply device 70. Circulate the cooling water sent out. As can be understood from FIGS. 16 and 22, the flow paths 75, 76 are positions where the compression member 40 is advanced to a near position where a gap corresponding to a desired thickness is formed between the compression member 40 and the front surface of the detection coil 11. However, it is provided at a position close to the cavity 30. The cooling water channels 75 and 76 correspond to the cooling means of the present invention.

  The control device 37 performs drive control by giving control signals to the molten resin supply device 33, the holding pin drive mechanism 35, the hydraulic device 36, the power supply device 50, the hot water supply device 60, and the cooling water supply device 70, respectively. The control device 37, the power supply device 50, and the hot water supply device 60 correspond to the heating control means of the present invention, and the control device 37 and the cooling water supply device 70 correspond to the cooling control means, respectively.

(2) Manufacturing Process of Proximity Sensor Next, the manufacturing process of the proximity sensor 10 will be described for each molding method (molding methods 1 to 3). Each molding method differs in the temperature at which the rod heater 45 generates heat, the temperature at which the hot water supply device 60 heats water, and whether the compression member 40 is rotated.
(Molding method 1)
The control device 37 drives the molten resin supply device 33 and simultaneously transmits drive operation signals S1 and S2 to the power supply device 50 and the hot water supply device 60, respectively, as shown in FIG. The hot water supply device 60 is driven. The power supply device 50 receives the drive operation signal S1, supplies power, and causes the rod heater 45 to generate heat at a temperature of 200 ° C. The molten resin J injected into the cavity 32 is not cured when the temperature is 200 ° C. On the other hand, the hot water supply device 60 receives the drive operation signal S2, heats the water at a temperature of 90 ° C., and sends the hot water to the flow paths 65 and 66.

  As shown in FIG. 19, the molten resin J is injected into the cavity 32 by the molten resin supply device 33, and when the compression member 40 has passed a predetermined time after the molten resin J is injected, the hydraulic device 36. The hydraulic cylinder moves forward toward the front surface of the detection coil 11 as shown in FIG. The compression member 40 is heated by the rod-shaped heater 45 and heats the molten resin J that comes into contact therewith. Here, the compression member 40 does not rotate.

  As shown in FIGS. 20 to 22, the hydraulic cylinder of the hydraulic device 36 is in a state where the compression member 40 is advanced to the near position where a gap corresponding to the desired thickness is formed between the compression member 40 and the front surface of the detection coil 11. (Corresponding to the “second step” of the present invention). The molten resin J is heated by the compression member 40 whose temperature has been raised by the rod-shaped heater 45 and heated by the hot water flowing through the flow paths 65 and 66 to maintain fluidity. As a result, the molten resin J reaches the entire periphery of the detection surface 10 a and the front end side portion of the circuit board 23.

  Thereafter, the control device 37 transmits drive stop signals S4 and S5 (see FIG. 4) to the power supply device 50 and the hot water supply device 60, respectively. The power supply device 50 receives the drive stop signal S4 and stops supplying power to the rod heater 45, and the hot water supply device 60 receives the drive stop signal S5 and sends hot water to the flow paths 65 and 66. Stop that. The molten resin J is stopped from being heated when the temperature of the compression member 40 decreases and the hot water does not flow through the flow paths 65 and 66.

  The control device 37 transmits the drive stop signals S4 and S5 to the power supply device 50 and the hot water supply device 60, respectively, and simultaneously transmits the drive operation signal S3 to the cooling water supply device 70. The cooling water supply device 70 receives the driving operation signal S <b> 3 and sends the cooling water to the flow paths 75 and 76. Then, the molding die 31 is cooled by cooling water flowing through the flow paths 75 and 76. The control device 37 transmits the cylinder operation signal S12 (see FIG. 4) to the hydraulic device 36 after transmitting the drive operation signal S3 to the cooling water supply device 70. The compression member 40 moves backward when the hydraulic device 36 receives the cylinder operation signal S <b> 12 and the hydraulic cylinder is accommodated in the hydraulic device 36. After the molten resin J is solidified by the cooling water flowing through the flow paths 75 and 76, the mold is removed, and the detection coil 11 and the circuit board 23 integrated by the primary molding member 24 are formed as shown in FIG. 6B. Manufactured. As described above, the control device 37 controls the power supply device 50 and the hot water supply device 60 to stop, and at the same time controls the cooling water supply device 70 to be driven, and then the hydraulic device to retract the compression member 40. 36 is controlled to be driven.

(Molding method 2)
Here, the description of the same manufacturing process as the forming method 1 is omitted. As shown in FIGS. 16 and 19, the control device 37 drives the molten resin supply device 33 to inject the molten resin J into the cavity 32, and at the same time, supplies the drive operation signals S1, S6 to the power supply device 50, The data is transmitted to the hot water supply device 60, and the power supply device 50 and the hot water supply device 60 are driven. The power supply device 50 receives the drive operation signal S1, supplies power, and causes the rod heater 45 to generate heat at a temperature of 200 ° C. The hot water supply device 60 receives the drive operation signal S6, heats the water at a temperature of 200 ° C., and sends the hot water to the flow paths 65 and 66. In this molding method 2, as in the molding method 1, the compression member 40 is not rotated.

(Molding method 3)
Here, unlike the molding methods 1 and 2, the compression member 40 is rotated by the hydraulic motor of the hydraulic device 36. As shown in FIGS. 16 and 19, the control device 37 drives the molten resin supply device 33 to inject the molten resin J into the cavity 32, and simultaneously outputs drive operation signals S8 and S2 to the power supply device 50, The data is transmitted to the hot water supply device 60, and the power supply device 50 and the hot water supply device 60 are driven. The power supply device 50 receives the drive operation signal S8 and supplies power to cause the rod heater 45 to generate heat at 90 ° C. The hot water supply device 60 receives the drive operation signal S2, heats the water at 90 ° C., and sends the hot water to the flow paths 65 and 66. When the temperature is 90 ° C. (curing start temperature), the molten resin J starts curing.

  When a predetermined time has elapsed since the injection of the molten resin J into the cavity 32, the controller 37 rotates the hydraulic motor rotation operation signal S9 and the hydraulic cylinder drive operation signal S10 as shown in FIG. Are transmitted to the hydraulic device 36, respectively. The hydraulic device 36 receives the rotation operation signal S9 and the drive operation signal S10, and as can be understood from FIGS. 20 to 22, the compression member 40 is rotated by the hydraulic motor and the hydraulic cylinder while rotating the front surface of the detection coil 11. To advance towards. The molten resin J is agitated by the rotation of the compression member 40 and heated by the hot water flowing through the compression member 40 and the flow paths 65 and 66 whose temperature has been increased by the rod heater 45, and the detection surface 10a while maintaining fluidity. And the entire periphery of the front end portion of the circuit board 23.

  Thereafter, the control device 37 transmits drive stop signals S4 and S5 (see FIG. 4) to the power supply device 50 and the hot water supply device 60, respectively. The power supply device 50 receives the drive stop signal S4 and stops supplying power to the rod heater 45, and the hot water supply device 60 receives the drive stop signal S5 and sends hot water to the flow paths 65 and 66. Stop that. The molten resin J is stopped from being heated when the temperature of the compression member 40 decreases and the hot water does not flow through the flow paths 65 and 66.

  The control device 37 transmits the drive stop signals S4 and S5 to the power supply device 50 and the hot water supply device 60, respectively, and simultaneously transmits the drive operation signal S3 to the cooling water supply device 70. The cooling water supply device 70 receives the driving operation signal S <b> 3 and sends the cooling water to the flow paths 75 and 76. Then, the molding die 31 is cooled by cooling water flowing through the flow paths 75 and 76. The control device 37 transmits a rotation stop signal S11 to the hydraulic device 36 after transmitting the drive operation signal S3 to the cooling water supply device 70. The hydraulic device 36 receives the rotation stop signal S11 and stops the rotation of the compression member 40. Subsequently, the control device 37 transmits a cylinder operation signal S12 to the hydraulic device. The compression member 40 moves backward when the hydraulic device 36 receives the cylinder operation signal S <b> 12 and the hydraulic cylinder is accommodated in the hydraulic device 36. As described above, the control device 37 controls the power supply device 50 and the hot water supply device 60 to stop and simultaneously controls the cooling water supply device 70 to be driven, and then stops the rotation of the compression member 40. Control is performed so that the hydraulic motor of the hydraulic device 36 is stopped, and subsequently, control is performed so as to drive the hydraulic cylinder of the hydraulic device 36 in order to retract the compression member 40.

2. Effect of Embodiment 2 (Effect of Forming Methods 1 to 3)
(1) Until the molten resin J injected into the cavity 32 is advanced to the near position where a gap corresponding to a desired thickness is formed between the compression member 40 and the front surface of the detection coil 11 in the second step. It is heated during As a result, the molten resin J can be pushed into the cavity 32 by the compression member 40 while preventing the molten resin J from being cured by heating, and the molten resin J is filled in the entire cavity 32 to suppress molding defects. can do.
(2) The control device 37 performs control so that the temperature value at which the rod heater 45 generates heat is equal to or higher than the temperature at which the hot water supply device 60 heats water. The temperature at which the rod heater 45 generates heat and the temperature at which the hot water supply device 60 heats water are 200 ° C. and 90 ° C. in the molding method 1, 200 ° C. in the molding method 2, and 90 ° C. in the molding method 3, respectively. Accordingly, the hot water flowing through the rod heater 45 and the flow paths 65 and 66 heats the compression member 40 and the molding die 31, respectively, and the temperature at which the molten resin J injected into the cavity 32 heats the molding die 31. It can prevent hardening with the compression member 40 heated at the above temperature, and can suppress the cause which produces the shaping | molding defect of an insert molded product.
(3) The control device 37 sets the temperature at which the rod heater 45 generates heat and the temperature at which the hot water supply device 60 heats water to a temperature equal to or higher than the curing start temperature (90 ° C.) of the molten resin J injected into the cavity 32. did. Thereby, it can prevent that the molten resin J inject | poured in the cavity 32 hardens | cures, and can suppress that the molding defect of an insert molded product arises. Further, the control device 37 sets the temperature at which the rod heater 45 generates heat or the temperature at which the hot water supply device 60 heats water to an optimum value according to the amount of heat generated by the rod heater 45, the size of the molding die 31, and the like. The heating control of the rod heater 45 and the hot water (heating fluid) can be optimized.
(4) After the 2nd process is complete | finished, the control apparatus 37 stops supplying the electric power to the rod heater 45, and the hot water supply apparatus 60 stops sending hot water to the flow paths 65 and 66 after the 2nd process is complete | finished. At the same time, the cooling water supply device 70 controls the cooling water to be sent out to the flow paths 75 and 76. When heating by the hot water flowing through the compression member 40 and the flow paths 65 and 66 is stopped, the molten resin J injected into the cavity 32 is molded by the cooling water flowing through the flow paths 75 and 76. The temperature of 31 can be lowered and curing can be promoted, and the molding time of the insert molded product can be shortened.
(5) The molding die 31 is heated by flowing hot water through the flow paths 65 and 66, the compression member 40 is heated by the rod heater 45, and the molding die 31 supplies cooling water to the flow paths 75 and 76. It is circulated and cooled. The molding die 31 can be heated or cooled only by circulating warm water or cooling water through each flow path, and the compression member 40 can be heated only by accommodating the rod heater 45. The molten resin J injected into the cavity 32 can be appropriately heated or cooled with a simple structure.
(6) As shown in FIGS. 16 to 22, the hot water flow paths 65 and 66 are provided in the vicinity of the end of the cavity 32 and on the front side in the advancing direction of the compression member 40. As a result, the molten resin J can be heated by warm water flowing in the vicinity of the cavity 32 to fill the entire cavity 32 while maintaining fluidity and preventing curing.
(7) When the hot water channels 65 and 66 are provided on the front side in the direction of travel of the compression member 40 relative to the gate 39, the molten resin J is compressed more than the gate 39 by the hot water flowing through the channels 65 and 66. It is possible to fill the cavity 32 while heating on the front side in the traveling direction of the member 40 to prevent hardening.
(8) The cooling water flow paths 75 and 76 are provided in the vicinity of the gate 39 as shown in the figure. Accordingly, it is possible to promote the cooling and hardening of the molten resin J injected into the cavity 32, and also to cool the molding die 31, and even if the operator touches the molding die 31, there is a burn. It can be avoided.

(Effect of molding method 1)
The control device 37 controls the molding die 31 to be heated at 90 ° C. by hot water flowing through the flow paths 65 and 66, and controls the rod-shaped heater 45 to heat the compression member 40 at 200 ° C. As a result, the molten resin J injected into the cavity 32 comes into contact with the compression member 40 heated at a temperature (200 ° C.) higher than the curing start temperature of the resin, and is cured in the vicinity of the compression member 40. Can be suppressed. Since the molten resin J is pushed and flows by the compression member 40, even if the temperature (90 ° C.) for heating the molding die 31 is lower than the temperature (200 ° C.) for heating the compression member 40, Curing is suppressed.

(Effect of molding method 2)
The controller 37 controls the molding die 31 to be heated at 200 ° C. with hot water flowing through the flow paths 65 and 66, and controls the rod-shaped heater 45 to heat the compression member 40 at 200 ° C. Since the temperature (200 ° C.) for heating the molding die 31 is the same as the temperature (200 ° C.) for heating the compression member 40, the heat is transmitted from the molding die 31 and the molten resin J is cured. Is suppressed.

(Effect of molding method 3)
In the second step, the hydraulic device 36 receives the rotation operation signal S9 and the drive operation signal S10 transmitted by the control device 37, and moves the compression member 40 to the front surface of the detection coil 11 while rotating the compression member 40 by the hydraulic motor and the hydraulic cylinder. To advance toward. Thereby, it is possible to suppress the molten resin J from being agitated by the rotating compression member 40 and staying in the cavity 32 and being cured, and an insert molded product in which the detection coil 11, the circuit board 23 and the resin are integrated. The cause of the molding failure can be suppressed. In this molding method 3, since the molten resin J is suppressed from being stirred and cured by the compression member 40, the temperature at which the molding die 31 is heated is suppressed to the curing start temperature (90 ° C.) of the molten resin J. Can do. Further, in this molding method 3, since the molding die 31 and the compression member 40 are controlled to be heated at 90 ° C., the molding method 31 and the compression member 40 are controlled to be heated at 200 ° C. Thus, it is not necessary to use the power supply device 50 and the hot water supply device 60 having a high capability value.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
(1) In the above-described embodiment, the circuit board 23 on which a circuit such as the LC parallel circuit 13 is mounted in addition to the detection coil 11 is also integrally molded. A configuration in which only a separate detection coil is primarily formed may be used.

  (2) Although the number of gates 39 is one in the above embodiment, a plurality of gates may be provided.

  (3) In the above embodiment, the holding pins 34 and 34 and the compression member 40 are driven by the control of the control device 37, but the present invention is not limited to this, and an operation by an operator may be used.

  (4) As described in the second embodiment, the molten resin J is not limited to being heated in the second step, and the compression member 40 is placed between the front surface of the detection coil 11 in the first to fourth steps. It may be heated until it is advanced to the near position where a gap corresponding to the desired thickness is formed.

(5) The hot water flow paths 65 and 66 are not limited to six, and may be configured by an appropriate number. The cooling water flow paths 75 and 76 are not limited to two, and may be configured by an appropriate number.
(6) As shown in FIGS. 16 and 17, the cooling water flow paths 75 and 76 may be additionally provided at the dotted line positions. The compression member 40 whose heating has been stopped is quickly cooled by the cooling water flowing through the flow paths 75 and 76. In addition, the molding die 31 can also be cooled quickly because the compression member 40 is cooled by the cooling water and heat is not transmitted from the compression member 40.

  (7) The insert molding device 30A is provided with a heat insulating material (for example, Rossna board) between the molding die 31 and the hydraulic device 36 or the power supply device 50, and hydraulic pressure is supplied when cooling water is circulated through the flow paths 75 and 76. The heat generated by the device 36 or the power supply device 50 may be suppressed from being transmitted to the molding die 31.

  (8) The control device 37 drives the power supply device 50 and the hot water supply device 60 to heat the compression member 40 at 90 ° C. or 200 ° C., or to send 90 ° C. or 200 ° C. hot water to the flow paths 65 and 66. However, the control device 37 may constantly control the temperatures of the compression member 40 and the molding die 31 to be 90 ° C. or 200 ° C., respectively.

  (9) The insert molding apparatus controls the first heating means for heating the mold, the second heating means for heating the compression member, and the second heating means so as to perform a heating operation at a predetermined temperature. Heating control means for controlling the first heating means to perform a heating operation at a temperature equal to or higher than the predetermined temperature, and drive means for causing the compression member to advance while rotating are provided. May be. This insert molding device 30 is configured so that the molten resin J is driven by the driving means (even if the temperature (eg, 90 ° C.) for heating the compression member 40 is lower than the temperature (eg, 200 ° C.) for heating the molding die 31. For example, it can be prevented from being stirred and hardened by the rotating compression member 40 by the control device 37), and by heating the molding die 31, the fluidity can be maintained and the entire cavity 32 can be filled.

  (10) FIG. 14 shows a modification to the first embodiment. That is, it is good also as a structure which prevents the position shift of the insert goods in the advancing direction with the pressure by a compression member by latching a holding pin (holding member) front-end | tip and the to-be-held part of an insert goods. As a specific configuration thereof, FIG. 1A shows a configuration in which locking protrusions 34 a and 34 a that lock the rear surface of the detection coil 11 are provided at the tips of the holding pins 34 and 34. Further, FIG. 5B shows a configuration in which the holding pins 34 and 34 are provided with convex portions 34b and 34b that fit into the recesses 11a and 11a formed on the side surface of the detection coil 11. On the contrary, a configuration in which a concave portion into which a convex portion formed on the side surface of the detection coil 11 is fitted may be provided at the tips of the holding pins 34 and 34.

The perspective view which shows the use condition of the proximity sensor which concerns on Embodiment 1 of this invention. Schematic showing the circuit configuration of the proximity sensor Cross section of proximity sensor Simplified diagram showing the overall configuration of the insert molding device Simplified view showing the upper mold The perspective view which shows the insert goods before and after the primary shaping | molding which concerns on Embodiment 1. FIG. Perspective view showing insert product before secondary molding Perspective view showing insert product after secondary molding The figure which shows the shaping die of Embodiment 1 which has arrange | positioned the insert goods. Diagram showing mold for molten resin injection The figure which shows the molding die at the time of compression member advance Diagram showing the mold when the gate is shut off The figure which shows the molding die at the time of a compression member stop Partial enlarged view showing a modification The figure which shows the metal mold used with the conventional molding method The simplified diagram which shows the whole structure of the insert molding apparatus which concerns on Embodiment 2. FIG. Simplified view showing the upper mold The figure which shows the shaping die of Embodiment 2 which has arrange | positioned the insert goods. Diagram showing mold for molten resin injection The figure which shows the molding die at the time of compression member advance Diagram showing the mold when the gate is shut off The figure which shows the molding die at the time of a compression member stop

Explanation of symbols

10: Proximity sensor 10a ... Detection surface (predetermined part)
11 ... Detection coil (insert product)
16 ... Light emitting element (indicator)
23 ... Circuit board 24 ... Primary molded member 24a ... Front wall 24b ... Small diameter portion 24c ... Projection (uneven shape)
25 ... Secondary molding member 26 ... Metal case 26a ... Through hole 30 ... Insert molding device 31 ... Mold 32 ... Cavity 34 ... Holding pin (holding member)
36 ... Hydraulic device (drive means)
37 ... Control device (heating control means, cooling control means)
39 ... Gate (inlet)
40 ... Compression member 45 ... Bar heater (second heating means)
50 ... Power supply device (heating control means)
60 ... Warm water supply device (heating control means)
65, 66 ... flow path of warm water (first heating means)
70 ... Cooling water supply device (cooling control means)
75, 76 ... Cooling water flow path (cooling means)
J: Molten resin

Claims (23)

An insert molding method in which a molten resin is injected into a cavity in a state where the insert product is disposed in a cavity of a molding die, and a predetermined portion of the insert product is resin-molded thinner than other portions. ,
A first step of injecting the molten resin from the predetermined part side of the insert part to the cavity;
A second step of causing the compression member provided in the cavity to be advanced toward the predetermined portion of the insert product to advance to a predetermined position before the predetermined portion during or after the first step; The insert molding method characterized by including these. In the state where the detection unit including at least the detection coil among the components of the proximity sensor is arranged in the cavity of the molding die, molten resin is injected into the cavity, and the detection surface of the detection unit is set to another part. An insert molding method in which the resin is molded into a thinner wall,
A first step of injecting the molten resin from the detection surface side of the detection unit into the cavity;
A second step of causing the compression member provided so as to be able to advance toward the detection surface of the detection unit in the cavity to advance to a predetermined position before the detection surface during or after the first step; An insert molding method comprising: Prior to the first step, a third step of holding the other part by a holding member provided so as to be able to advance and retreat with respect to the inside of the cavity;
The insert molding method according to claim 1, further comprising a fourth step of retracting the holding member from the cavity during the advancement of the compression member in the second step.   The molten resin injected into the cavity in the first step is heated at least until the compression member is advanced to the predetermined position in the second step. 4. The insert molding method according to any one of 3.   The insert molding method according to claim 1, wherein in the second step, the compression member is advanced while rotating.   6. The insert molding method according to claim 1, wherein the molten resin injected into the cavity is cooled by finishing heating after the second step is finished. An insert molding apparatus for injecting molten resin into a cavity in a state where the insert product is placed in a cavity of a mold, and molding a predetermined portion of the insert product thinner than other portions. There,
A cavity in which the insert product is disposed, a compression member provided so as to be able to advance toward the predetermined part of the insert product in the cavity, and formed in a side wall of the cavity in the course of the compression member A mold having an injection port for injecting the molten resin into the cavity,
An insert molding apparatus comprising: drive means for advancing the compression member to a predetermined position before the predetermined portion after the injection of the molten resin from the injection port is started.   8. The insert molding apparatus according to claim 7, wherein the compression member closes the injection port by moving while the side surface is in sliding contact with the peripheral portion of the injection port in the advancement process.   The insert molding apparatus according to claim 7 or 8, wherein the driving means advances the compression member by hydraulic pressure. First heating means for heating the mold,
A second heating means for heating the compression member;
Heating control means for controlling the first heating means to perform a heating operation at a predetermined temperature and controlling the second heating means to perform a heating operation at a temperature equal to or higher than the predetermined temperature. The insert molding apparatus according to any one of claims 7 to 9, wherein   The insert molding apparatus according to claim 10, wherein the driving unit rotates the compression member.   The heating control unit heats at least one of the first heating unit and the second heating unit at a temperature equal to or higher than a curing start temperature at which a molten resin injected into the mold cavity starts curing. The insert molding device according to claim 10 or 11, wherein   The heating control means controls the first heating means to heat the mold at a temperature equal to or higher than the curing start temperature of the molten resin, and the second heating means controls the compression member to be higher than the curing start temperature. The insert molding apparatus according to claim 12, wherein the insert molding apparatus is controlled to be heated at a high temperature. Cooling means for cooling the mold,
Cooling control means for controlling to drive or stop the cooling means,
The cooling control unit is controlled to drive the cooling unit on condition that the heating control unit controls to stop heating the first and second heating units. The insert molding apparatus according to any one of claims 10 to 13. The first heating means is constituted by a flow path of a heating fluid provided in the mold, and the second heating means is constituted by a heating element accommodated in the compression member,
The insert molding apparatus according to any one of claims 10 to 14, wherein the cooling means is configured by a flow path of a cooling fluid provided in the mold.   The insert molding device according to claim 15, wherein the flow path of the heating fluid is provided in the vicinity of the end of the cavity and on the front side in the advance direction of the compression member.   The insert molding apparatus according to claim 15 or 16, wherein the flow path of the cooling fluid is provided in the vicinity of an inlet of the molding die.   The insert molding device according to any one of claims 15 to 17, wherein the flow path of the heating fluid is provided on the front side in the traveling direction of the compression member with respect to the injection port. At least the detection coil is a proximity sensor in which the detection surface, which is one side surface of the detection coil, is formed by resin molding thinner than other parts in the cavity of the molding die,
The detection coil disposes the detection coil in the cavity of the mold, starts injecting molten resin into the cavity from the detection surface side of the detection coil, and directs the compression member toward the detection surface. A proximity sensor, wherein the detection surface is formed thinner than other portions by advancing to a predetermined position before the detection surface. A circuit board electrically connected to the detection coil and integrally formed with the detection coil by the molding;
The proximity sensor according to claim 19, wherein substantially the same amount of electronic components are mounted on the front surface and the back surface of the circuit board. The molding is primary molding, and parts other than the primary molded primary molding part are secondary molded by resin molding,
The proximity sensor according to claim 19 or 20, wherein a joint portion between the primary molded portion and the secondary molded secondary molded portion is formed in an uneven shape. The molding is a primary sensor, and a proximity sensor in which a portion other than the primary molding portion is secondary molded by resin molding in a state in which the primary molding primary molding portion is accommodated in a cylindrical metal case. ,
The proximity sensor according to any one of claims 19 to 21, wherein a through hole is formed in a side wall of the metal case at a position where the molding resin by the secondary molding is filled. A circuit board electrically connected to the detection coil and integrally formed with the detection coil by the primary molding;
The circuit board is mounted with an indicator lamp that emits light based on a predetermined detection operation at a location covered with the secondary molding resin.
23. The proximity sensor according to claim 21, wherein the secondary molding resin is a translucent material capable of transmitting light from the indicator lamp.

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