JP2013149807A - Temperature sensor and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature sensor which enables a thermistor to be disposed on a substantially center line of an electric wire to which the temperature sensor is attached when the temperature sensor, formed by enclosing sealed components with a resin, is manufactured, and to provide a manufacturing method of the temperature sensor.SOLUTION: When a sealed member 1 is placed in cavities 13 of molds 11, 12 and a melting resin 3 is poured into the cavities 13, the sealed member 1 is held by a cylindrical jig 15 from a circumferential direction to be positioned at a predetermined position before the resin 3 is poured. As the pouring of the melting resin 3 starts and the melting resin 3 fills the cavities 13, the cylindrical jig 15 is retreated to the exterior of the cavities 13. This method enables positioning of the sealed member 1 with high accuracy.

Description

  The present invention relates to a temperature sensor in which a thermistor is sealed with a resin using an injection molding method and a method for manufacturing the same.

  For example, as disclosed in Patent Document 1, Patent Document 2, or Patent Document 3 or the like, a temperature sensor in which a thermistor or the like is encased in a thermoplastic resin by injection molding in order to enhance waterproofness is already known. .

  The temperature sensor preferably has a configuration in which the thermistor and the coated lead wire are positioned on substantially the same line. The reason is that it is excellent in moisture resistance and electrical insulation.

  However, in reality, there is a problem that the position of the thermistor is displaced from the axis of the coated lead wire due to the pressure of the molten resin injected into the cavity of the mold of the injection molding apparatus.

JP-A-2-46121 JP-A-8-69904 JP 2011-222782 A

  In the technology of the invention described in the cited documents 1 to 3, as described above, as shown in FIGS. 9 and 10, the cavity 63 formed between the upper mold 61 and the lower mold 62 is formed in the cavity 63. When the resin 65 is injected from the gate 64, the thermistor 55 is pushed by the flow of the injected resin 65 and is pushed to the opposite side of the gate 64 to flow. For this reason, there is a problem that an uneven portion is generated in the insulating coating thickness of the thermistor 55.

  The present invention solves the above-mentioned problems, and provides a temperature sensor that can be injection-molded so that the thermistor is positioned substantially on the axis of the covered electric wire against the molten resin pressure during injection molding, and a method for manufacturing the same. It is intended.

  In order to solve the above-described problems, the present invention provides a temperature sensor capable of wrapping a sealed member with a resin and embedding a thermistor at a predetermined position using an injection molding method, and a method for manufacturing the same. When injecting molten resin by placing a member to be sealed in the mold cavity, hold the member to be sealed from its circumferential direction by a cylindrical jig and position it in place before injecting the resin. The cylindrical jig is discharged from the inside of the cavity to the outside of the cavity as the molten resin is injected into the cavity and filled.

  According to this method, when the resin is injected, since the member to be sealed is held in the cylindrical jig and positioned at a predetermined position, the member to be sealed can be positioned satisfactorily. In particular, since the member to be sealed is held in a state where the position of the member to be sealed is restricted over the entire circumference in the circumferential direction, the member to be sealed can be positioned extremely well.

  Further, the present invention is characterized in that the cylindrical jig is discharged from the inside of the cavity to the outside of the cavity by using the pressure that the resin flows in when the resin is injected into the cavity and pushes the cylindrical jig. . According to this method, the cylindrical jig is moved from the cavity to the outside of the cavity without applying an external force to the cylindrical jig, for example, a force from a drive mechanism such as an external cylinder or an external motor that is mechanically moved. Therefore, it is not necessary to provide a drive mechanism for moving the cylindrical jig, and the manufacturing cost of the sealed molded body can be reduced.

  Further, according to the present invention, when the cavity is being filled with molten resin, a force for discharging the cylindrical jig out of the cavity is applied from the outside to discharge the cylindrical jig out of the cavity. It is characterized by that. According to this method, even when the pressing force to the cylindrical jig when the resin flows into the cavity is small and it is difficult to discharge the cylindrical jig out of the cavity with this pressing force alone, With this force, the cylindrical jig can be discharged well out of the cavity, and the sealed molded body can be manufactured well.

  In addition, it is desirable that the cylindrical member holds the member to be sealed in a posture in which the central axis of the member to be sealed and the central axis of the cylindrical member coincide with each other. According to this, since the center axis of the member to be sealed and the center axis of the cylindrical jig coincide with each other, the member to be sealed can be stably held in a very good posture.

  In addition, with the columnar guide member whose tip end faces the cavity of the mold inserted into the cylindrical jig, the cylindrical jig is arranged to be freely retractable along the axial direction. According to this method, the cylindrical jig can be discharged well from the cavity to the outside while being stably guided by the guide member having a simple structure.

  Moreover, when the member to be sealed is a component connected to the conductor portion of the electric wire, a sealed molded body in which the component is well sealed and connected can be obtained. In addition, by placing a gate for injecting resin into the cavity at a position facing the wiring part where the covering of the electric wire has been peeled off or in the vicinity thereof, the cylindrical jig is inserted into the cavity by the resin injected into the cavity. Can be discharged well out of the cavity.

  It should be noted that the temperature sensor used in the present invention is replaced with the exemplified temperature sensor, and disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 8-69904) and / or Patent Document 3 (Japanese Patent Laid-Open No. 2011-222782) disclosed in the prior art document column. Can be employed.

  According to the present invention, when the sealed member is placed in the mold cavity and the molten resin is injected, the sealed member is held from the circumferential direction by the cylindrical jig before the resin is injected. Then, as the molten resin is started and filled in the cavity, the cylindrical jig is retracted from the cavity to the outside of the cavity, so that the member to be sealed can be positioned satisfactorily. In particular, since the member to be sealed can be held by the cylindrical jig from the circumferential direction, that is, in a state in which the position is restricted over the entire circumference in the circumferential direction, positioning of the member to be sealed can be performed extremely well. As a result, not only can sealing performance such as good waterproofness be obtained as a member to be sealed, but, for example, when a temperature sensor is provided as the member to be sealed, the sealing molded body as the temperature sensor device It is possible to obtain a highly reliable temperature sensor in which detection sensitivity and response accuracy are maintained extremely well.

  In addition, by using the pressure that the resin flows in when the resin is injected into the cavity and pushes the cylindrical jig, the cylindrical jig is retracted out of the cavity, so that an external force such as a machine is applied to the cylindrical jig. Because the cylindrical jig can be discharged out of the cavity without applying a force to move it, it is not necessary to provide a drive mechanism for moving the cylindrical jig, and the manufacturing cost of the temperature sensor Can be made inexpensively.

  Further, when the molten resin is being filled in the cavity, a force for retracting the cylindrical jig out of the cavity is applied from the outside, and the cylindrical jig is discharged out of the cavity from the cavity, thereby entering the cavity. Even when it is difficult to eject the cylindrical jig out of the cavity with only the pressing force applied to the cylindrical jig when the resin flows in, the cylindrical jig can be discharged out of the cavity well by force from the outside. Temperature sensor can be manufactured satisfactorily.

It is sectional drawing of the temperature sensor manufactured by the manufacturing method which concerns on embodiment of this invention. It is sectional drawing which shows the manufacturing process of the manufacturing method of the temperature sensor which concerns on embodiment of this invention, and shows the state which has arrange | positioned the to-be-sealed member in the cavity of a metal mold | die. It is a perspective view which shows the manufacturing process of the manufacturing method of the temperature sensor which concerns on embodiment of this invention, and shows the state which hold | maintained the to-be-sealed member with the cylindrical jig | tool. It is sectional drawing which shows the manufacturing process of the manufacturing method of the temperature sensor which concerns on embodiment of this invention, and shows the state which started inject | pouring resin in the cavity of a metal mold | die. It is sectional drawing which shows the manufacturing process of the manufacturing method of the temperature sensor which concerns on embodiment of this invention, and shows the state in the middle of injecting resin in the cavity of a metal mold | die. It is sectional drawing which shows the manufacturing process of the manufacturing method of the temperature sensor which concerns on embodiment of this invention, and shows the state which has finished inject | pouring resin in the cavity of a metal mold | die. It is sectional drawing of the temperature sensor manufactured with the conventional manufacturing method. It is sectional drawing which shows the manufacturing process of the manufacturing method of the conventional temperature sensor, and shows the state which has arrange | positioned the to-be-sealed member in the cavity of a metal mold | die. It is sectional drawing which shows the manufacturing process of the manufacturing method of the conventional temperature sensor, and shows the state which started pouring resin into the cavity of a metal mold | die. It is sectional drawing which shows the manufacturing process of the manufacturing method of the conventional temperature sensor, and shows the state which has finished inject | pouring resin in the cavity of a metal mold | die.

  A method for manufacturing a temperature sensor according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view of a temperature sensor manufactured by a manufacturing method according to an embodiment of the present invention, and FIGS. 2 to 6 are cross-sectional views showing respective manufacturing steps of the temperature sensor manufacturing method according to the embodiment. 3 is a perspective view).

  First, a temperature sensor manufactured by a method of manufacturing a temperature sensor according to an embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, in this embodiment, the sealed member 1 is a thermistor for temperature detection and is connected to the electric wire 2. Specifically, the member to be sealed 1 is a thermistor, which is a thin plate-like thermistor element 1a and two connection terminals (conductor portions) protruding from one surface and the other surface (that is, both surfaces) of the thermistor element 1a. 1b. The electric wire 2 includes a covering portion (external covering) 2a and two wiring portions 2b embedded inside the covering portion 2a. The wiring portion 2b further includes an insulating covering 2c and a conductor. It is comprised from the conducting wire part 2d. And the coating | coated part 2a and the insulation coating 2c of the front-end | tip part of the electric wire 2 are peeled, and the conducting wire part 2d is exposed, The connection terminal 1b of the thermistor element 1a as the to-be-sealed member 1 is soldered to this conducting wire part 2d, They are connected by welding, pressure bonding, or adhesion using an adhesive.

  The sealed member 1 configured as described above and the tip end portion of the electric wire 2 connected to the sealed member 1 (specifically, the conductive wire portion 2d and the covering portion 2a from which the insulating coating 2c has been peeled off are peeled off). The wiring part 2b (insulation coating 2c) and the tip part of the coating part 2a are sealed in a state of being wrapped from the outer periphery by a thermoplastic resin (resin sealing part) 3, so that the temperature sensor 4 is configured. Has been.

  A manufacturing method of the temperature sensor 4 will be described with reference to FIGS. In FIG. 2, 11 is an upper mold, 12 is a lower mold, and these upper mold 11 and lower mold 12 are disposed so that they can be moved up and down relatively. A cavity (resin injection space) 13 into which the resin 3 is injected when the two are combined is formed. In addition, a gate 14 serving as an injection port for injecting resin into the cavity 13 is formed in the upper mold 11 (or the lower mold 12).

  The upper mold 11 and the lower mold 12 are configured so that the electric wire 2 is sandwiched in one area (the left area in FIGS. 2 and 4 to 6) where the upper mold 11 and the lower mold 12 are combined. A cylindrical jig (sleeve-like jig) that holds the member 1 to be sealed from the circumferential direction in the other area (the right-hand area in FIGS. 2 and 4 to 6) where the lower mold 12 and the lower mold 12 are combined. ) 15 and a guide member 16 for guiding the cylindrical jig 15.

  Here, in this embodiment, the cylindrical jig 15 is a metal cylindrical body, and the guide member 16 is a metal columnar body. Further, the inner peripheral dimension of the cylindrical jig 15 and the outer peripheral dimension of the guide member 16 are made to correspond to each other, and the cylindrical member 15 is aligned with the center axis of the guide member 16 and the cylindrical jig 15 aligned. The tool 15 is slidable along the axial direction. The guide member 16 is slightly longer in the axial direction than the cylindrical jig 15, and one end of the guide member 16 is sandwiched between the upper mold 11 and the lower mold 12 so that the position of the guide member 16 is fixed. Is done.

  The cylindrical jig 15 has an inner diameter that is to be sealed with the resin 3 (the maximum diameter of the sealed member 1 and the tip of the electric wire 2 (in this embodiment, the maximum diameter of the thermistor element 1a)). The dimension is substantially the same, or the diameter is slightly larger than the maximum diameter of the object to be sealed, and the object to be sealed (in this embodiment, the sealed member 1 and the wire connected to the sealed member 1) 2 is preferably a length that is smaller than the length of the object to be sealed, and the gate 14 serving as an injection port for injecting the resin 3 into the cavity 13 is an electric wire. The wiring portion 2b (insulating coating 2c) from which the two covering portions 2a have been peeled is disposed at a position facing from the side (in this embodiment, from above).

  In the above configuration, when the sealed member 1 is placed in the cavity 13 and the molten resin 3 is injected, as shown in FIG. 2 and FIG. 1 is held from the circumferential direction by a cylindrical jig 15 and fixed at a predetermined position. For example, in a state where the upper mold 11 is separated upward from the lower mold 12, the electric wire 2, the sealed member 1, the guide member 16, and the cylindrical jig are disposed at locations corresponding to the cavities 13 on the lower mold 12. The tool 15 is placed, and the cylindrical jig 15 is protruded into the cavity 13 to a position surrounding the sealed member 1 and the distal end portion of the electric wire 2 connected to the sealed member 1. Hold 1 etc. In this state, the upper mold 11 is moved down to match the lower mold 12.

  Next, as shown in FIG. 4, injection of the molten resin 3 into the cavity 13 through the gate 14 is started. At this time, since the member 1 to be sealed is held in the circumferential direction by the cylindrical jig 15 and fixed at a predetermined position, even if the resin 3 flows into the cavity 13, it flows to the opposite side of the gate 14. Such a problem does not occur. In particular, since the sealed member 1 is held by the cylindrical jig 15 in a state where the position of the sealed member 1 is restricted over the entire circumference in the circumferential direction, the sealed member 1 can be positioned extremely well. That is, as a method of holding the member 1 to be sealed, it is conceivable to provide a holding pin or the like to hold the member 1 to be sealed at a plurality of points. Since the position of the member to be sealed 1 is restricted not only by the circumferential direction but by the surface instead of the point, the member to be sealed 1 can be positioned much better than when held by a holding pin or the like.

  Thereafter, as shown in FIGS. 5 and 6, as the molten resin 3 is filled in the cavity 13, the cylindrical jig 15 is retracted (exhausted) from the cavity 13 to the outside of the cavity 13. At this time, for example, when the resin 3 flows into the cavity 13, the cylindrical jig 15 is retracted out of the cavity 13 using the pressure by which the resin 3 flows and pushes the cylindrical jig 15.

  Thereby, the sealing molded object 4 by which the to-be-sealed member 1 was arrange | positioned in the center (axial center position) can be manufactured favorably, for example, when the to-be-sealed member 1 is a thermistor used as a temperature sensor In this case, since the thickness of the resin 3 around the member 1 to be sealed becomes extremely uniform, the detection sensitivity and response accuracy of the temperature sensor are kept very good, and a highly reliable one can be obtained. Therefore, the electrical component or electronic component provided with such a temperature sensor 4 has high reliability.

  Also, the cylindrical jig 15 is discharged (retracted) from the cavity 13 to the outside of the cavity 13 by using the pressure that the resin 3 flows into the cavity 13 when the resin 3 is injected into the cavity 13 and pushes the cylindrical jig 15. Thus, it is not necessary to provide a separate drive mechanism for moving the cylindrical jig 15 from the outside, so that the manufacturing cost of the sealed molded body 4 can be reduced.

  However, the present invention is not limited to this, and a cylinder device or the like that moves the cylindrical jig 15 from the outside is provided. When the molten resin 3 is being filled in the cavity 13, the cylindrical jig 15 is moved outside the cavity 13. The cylindrical jig 15 may be discharged out of the cavity 13 by applying a force to be discharged to the outside by a drive mechanism such as an external cylinder or an external motor that is mechanically moved. Thereby, even when it is difficult to discharge the cylindrical jig 15 out of the cavity 13 only by the pressing force to the cylindrical jig 15 when the resin 3 flows into the cavity 13, the cylindrical shape is generated by an external force. The jig 15 can be discharged well out of the cavity 13, and the reliability can be improved. The timing at which the cylindrical jig 15 is discharged is adjusted according to the injection amount of the resin 3, such as the amount of movement of the cylinder device that injects the resin 3, or a detection means for detecting the pressure in the cavity 13 is provided. The pressure may be adjusted according to the pressure, but is not limited thereto.

  Further, by adjusting the positions of the member to be sealed 1 and the cylindrical jig 15 with respect to the cavity 13 where the resin 3 is injected, the member to be sealed 1 is placed at a predetermined position other than the center of the temperature sensor 4 (resin 3). The present invention can also be favorably applied to a position (for example, a place away from the upper end by a predetermined distance or a place away from another part by a predetermined distance). Further, the cylindrical jig 15 is not limited to a cylindrical shape, and a rectangular cylindrical shape or other cylindrical shapes can be used according to the shape of the member 1 to be sealed.

  It should be noted that the temperature sensor used in the present invention is replaced with the temperature sensor exemplified in the above-described detailed description, and is disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 8-69904) and / or Patent Document disclosed in the column of the prior art document. 3 (Japanese Unexamined Patent Application Publication No. 2011-222782) can be used.

1 Thermistor (sealed member)
1a Thermistor element 1b Connection terminal (conductor part)
2 Electric wire 2a Cover 2b Wiring 2c Insulation 2d Conductor (conductor)
3 Resin 4 Temperature sensor 11 Upper mold 12 Lower mold 13 Cavity (Resin injection space)
14 Gate 15 Cylindrical jig (sleeve-shaped jig)
16 Guide member

Claims (9)

  A thermistor element, a sealed member provided with a conductor of an electric wire electrically connected to both surfaces of the thermistor element, and a resin sealing portion in which an electrically insulating resin is injection-molded around the sealed member A temperature sensor comprising: a cylindrical jig detachably installed in a cavity of a mold when the electric insulating resin is injection-molded; A temperature sensor manufactured by injection molding while discharging the cylindrical jig from the cavity while supporting the sealing member on the substantially axis of the electric wire.   The temperature sensor according to claim 1, wherein the thermistor element is a thermal element having a pair of connection terminals on both sides.   2. The temperature sensor according to claim 1, wherein the thermistor element is a thermosensitive element having a thin plate-like thermistor body and electrodes provided on both sides thereof. A method of manufacturing a temperature sensor that uses an injection molding method to manufacture a sealed molded body in which at least a portion of a thermistor as a sealed member to be sealed is wrapped with a resin,
When injecting molten resin by placing a member to be sealed in the cavity of the mold, the member to be sealed is held in the circumferential direction by a cylindrical jig and fixed in place before injecting the resin. ,
A method of manufacturing a temperature sensor, comprising: discharging the cylindrical jig from the inside of the cavity to the outside of the cavity as the molten resin is injected into the cavity and filled.   5. The temperature according to claim 4, wherein the cylindrical jig is discharged from the cavity to the outside of the cavity by using a pressure that the resin flows into the cavity when the resin is injected and pushes the cylindrical jig. Sensor manufacturing method.   When the molten resin is being filled in the cavity, a force for retracting the cylindrical jig out of the cavity is applied from the outside to discharge the cylindrical jig out of the cavity from the cavity. Item 5. A method for producing a temperature sensor according to Item 4.   5. The sealed member is held by the tubular jig so that a central axis of the sealed member and a central axis of the cylindrical jig coincide with each other. The manufacturing method of the temperature sensor of any one of -6.   The cylindrical jig is disposed so as to be freely retractable along the axial direction of the cylindrical jig in a posture in which a columnar guide member whose front end faces the cavity of the mold is covered in the circumferential direction. The manufacturing method of the temperature sensor of any one of Claims 4-7 characterized by these.   The member to be sealed is a component connected to the conductor portion of the electric wire, and a gate for injecting resin into the cavity is disposed at a position facing the wiring portion from which the covering portion of the electric wire is peeled off The manufacturing method of the temperature sensor of any one of Claims 4-8.

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