WO2014188707A1

WO2014188707A1 - Die for temperature sensor, production method, and temperature sensor

Info

Publication number: WO2014188707A1
Application number: PCT/JP2014/002638
Authority: WO
Inventors: 秀和福島
Original assignee: 株式会社デンソー
Priority date: 2013-05-23
Filing date: 2014-05-20
Publication date: 2014-11-27
Also published as: JP6102510B2; CN105228807A; JP2014226862A; CN105228807B

Abstract

In a die which forms a cavity of cylindrical shape, in addition to a first venting passage (A1) situated at an end (a first end) at a side where a temperature sensing unit is housed, a second gas venting passage (A3) through which the cavity communicates with the outside of the mold is situated between the gate and the end (first end) at the side where the temperature sensing unit is housed.

Description

Mold for manufacturing temperature sensor, manufacturing method, and temperature sensor

Cross-reference of related applications

This disclosure is based on Japanese Application No. 2013-109052 filed on May 23, 2013, the contents of which are incorporated herein by reference.

The present disclosure relates to a mold used for manufacturing a temperature sensor in which a housing is resin-molded, a manufacturing method, and a temperature sensor.

Patent Document 1 discloses a temperature sensor that is attached to the outside of a vehicle body and used to detect an outside air temperature. In general, a temperature sensor used to detect the outside air temperature includes a temperature sensing unit for detecting the temperature, a lead wire for extracting a signal from the temperature sensing unit, and a signal from the lead wire to an external device. The terminal for outputting and the housing which accommodates these are provided. The housing is integrally molded so as to accommodate the temperature sensitive part, the lead wire, and the terminal by injection molding. In more detail, it shape | molds as follows.

First, the temperature sensing portion and the lead wire, and the lead wire and the terminal are electrically and mechanically connected to manufacture a structure including the temperature sensing portion, the lead wire, and the terminal. In addition, the temperature sensitive part uses what coat | covered the well-known thermistor with the epoxy resin etc., and has a size larger than the part of a lead wire or a terminal in a structure.

The mold for molding the housing is provided with a structure support for fixing the structure at a position designed in advance in the housing when completed. The structure support portion may be, for example, an insertion port into which a portion of the terminal to be exposed in the finished product is inserted. That is, by inserting the exposed portion of the terminal into this insertion port, the structural component is fixed in the hollow portion (cavity) of the mold.

After setting the structure in the mold, the molten resin is injected into the cavity from the gate. The molten resin injected into the cavity from the gate spreads along the outer periphery of the cavity (that is, the surface in contact with the mold) and gradually cools and solidifies from the portion in contact with the mold. In addition, the mold part which shape | molds the edge part of a housing is provided with the vent hole for releasing the gas in a cavity, and gas is exhausted from a vent hole with injection | pouring of melted resin. In the above manufacturing method, the temperature sensor in which the temperature sensing portion, the lead wire, and the terminal are housed in the housing is manufactured by filling the cavity with the molten resin and solidifying.

JP 2008-101550 A

However, if the resin reaches the vent hole before the gas has escaped from the cavity, the vent hole is prevented by the resin, leaving the gas in the cavity. Due to the residual gas, the melted resin cannot be filled in the cavity and voids are generated.

In addition, as described above, the size of the temperature sensing part of the structure is larger than that of the lead wire and the terminal part. Therefore, the space near the temperature sensitive part is narrower than other parts. Further, since the melted resin flows around the cavity from the outer periphery along the mold, the narrow portion becomes further narrowed with the inflow of the resin, and the gas is more difficult to escape.

If the resin is filled in the narrow portion before the gas has completely escaped from the space from the gate to the narrow portion, the gas remains in the space from the gate to the narrow portion and voids are generated. Therefore, in the case where the narrow portion by the temperature sensing portion is provided in the cavity as described above, the possibility that a void is generated is higher than the case where the narrow portion is not provided.

The present disclosure has been made based on the above circumstances, and the object of the present disclosure is to manufacture a temperature sensor that can suppress the generation of voids between the gate and the temperature sensing portion. An object is to provide a mold, a manufacturing method, and a temperature sensor.

The temperature sensor manufacturing mold for achieving the object is disclosed as a temperature for molding a housing for housing a structure in which a temperature sensing portion, a lead wire, and a terminal are linearly connected in this order. A mold for manufacturing a sensor, wherein a direction in which the temperature sensing portion, the lead wire, and the terminal are continuous is an axial direction, and a cylindrical cavity that houses the structure, and an end of the cavity, A first gas vent passage communicating the cavity and the outside of the mold to vent the gas in the cavity to the first end of the structure on the side accommodating the temperature sensing part, and the first of the cavity The structure is arranged at a predetermined position in the cavity by being inserted into a terminal that is not connected to the lead wire at the second end that is the end opposite to the one end. In A structure support portion to be held, a gate formed between the second end portion and the temperature sensing portion, for injecting resin into the cavity, and between the first end portion and the gate, In order to escape the gas in the cavity, a second vent passage that communicates the cavity and the outside of the mold is provided.

According to the above configuration, the gas in the cavity is not only from the first gas vent passage provided at the end portion (first end portion) on the side where the temperature sensing portion is accommodated, but also from the second gas vent passage. Exhausted. Since the second gas vent passage is provided between the gate and the first end portion, it is suitable for discharging the gas existing in the space from the gate to the first end portion. Therefore, it becomes easier for gas to escape from the space from the gate to the first end than when the second gas vent passage is not provided.

Here, since the space from the gate to the first end portion also includes the space from the gate to the temperature sensing portion, gas easily escapes from the space from the gate to the first end portion, Gas can easily escape from the space from the gate to the temperature sensing part. That is, it becomes difficult for gas to remain in the space from the gate to the temperature sensing part, and generation of voids can be suppressed.

Further, the disclosure of the manufacturing method is a method of manufacturing a temperature sensor in which the housing is injection-molded by injecting a molten resin into the cavity from the gate of the mold.

Furthermore, the disclosure of the temperature sensor accommodates a structure in which the temperature sensing part, the lead wire, and the terminal are connected in a straight line in this order, and the direction in which the temperature sensing part, the lead wire, and the terminal are joined is determined. It is a temperature sensor provided with the cylindrical housing made into an axial direction, Comprising: It is a temperature sensor provided with a level | step-difference part in the 1st end part of the side which accommodates the said temperature sensing part among the edge parts of the said housing.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. The drawing
It is the schematic diagram showing an example of the state which has attached the temperature sensor 100 to the vehicle, It is typical sectional drawing of the temperature sensor 100, It is a schematic diagram of the structure 101, It is sectional drawing of the 1st metal mold | die 50B used in a comparison structure, FIG. 5 is a cross-sectional view taken along one-dot chain line 5-5 in FIG. It is a figure for demonstrating the process in which melted resin flows in into trunk part space C21, It is sectional drawing of the 2nd metal mold | die 50A used by this embodiment, FIG. 8 is a cross-sectional view taken along one-dot chain line 8-8 in FIG. FIG. 6 is an exploded view for explaining the structure of a base mold 51, a first head side mold 52, a second head side mold 53, and a third head side mold 54; It is an enlarged view of the part which forms head part 21H in the 2nd metallic mold 50A, It is sectional drawing corresponding to FIG. 8 in a modification.

Hereinafter, a structure of the temperature sensor 100 according to the present disclosure and an embodiment of a manufacturing method thereof will be described with reference to FIGS. First, before describing the manufacturing method of the temperature sensor 100, an outline of the configuration of the temperature sensor 100 will be described. FIG. 1 is a reference diagram illustrating an example of a state in which the temperature sensor 100 is attached to a vehicle. As shown in FIG. 1, the temperature sensor 100 is attached to, for example, a vehicle front bumper Fr or the like via a clamp member 30. An arrow A in FIG. 1 indicates the horizontal direction, and the temperature sensor 100 receives wind in the direction indicated by the arrow A when the vehicle travels. 1 is merely an example. For example, the temperature sensor 100 is mounted upside down with respect to FIG. 1, or the longitudinal direction of the body portion 21 is perpendicular to the direction of the arrow. It may be attached in a posture.

FIG. 2 is a diagram schematically showing a cross-sectional structure of the temperature sensor 100. A temperature sensor 100 shown in FIG. 2 includes a temperature sensing unit 10, a lead wire 13, a terminal 14, a body unit 21, a support unit 22, and a clamp fitting unit 23. The body part 21 accommodates the temperature sensing part 10, the lead wire 13 drawn from the temperature sensing part 10, and the terminal 14. In addition, although the trunk | drum 21, the support part 22, and the clamp fitting part 23 are each distinguished and called here, these are integrally molded by the manufacturing method mentioned later. Hereinafter, each unit will be described.

The temperature sensing unit 10 includes a normal thermistor element 11 having a predetermined temperature characteristic. The thermistor element 11 is connected to a lead wire 13 for detecting a change in resistance value of the thermistor element 11, and the thermistor element 11 is also connected to the first terminal of the lead wire 13 connected to the thermistor element 11 by an epoxy resin 12. It is coated integrally. Of the terminals of the lead wire 13, the second terminal 13 b that is not connected to the thermistor element 11 is electrically connected to the third terminal 14 a of the terminal 14. And the temperature sensing part 10 including the thermistor element 11, the lead wire 13, and the terminal 14 are integrally accommodated in the body part 21 formed of resin. In addition, the terminal 14, the lead wire 13, and the temperature sensing part 10 are arranged on the substantially straight line in this order.

The body part 21 has a cylindrical shape whose axial direction is the direction in which the terminal 14, the lead wire 13, and the temperature sensing part 10 are connected. That is, the axial direction here coincides with the aforementioned longitudinal direction. Here, the columnar shape includes not only a perfect circle in a cross section perpendicular to the axial direction but also an ellipse or a part having a straight portion on the outer periphery. Further, a portion of the body portion 21 near the temperature sensing portion 10 is referred to as a head portion 21H. The body portion 21 corresponds to a housing.

In addition, a connector portion 21C having an open shape is provided at the end of the body portion 21 opposite to the head portion 21H so that the fourth terminal 14b that is not connected to the lead wire 13 at the terminal 14 is exposed. Yes. The fourth terminal 14b of the terminal 14 exposed in the connector portion 21C is connected to a connection terminal of an external device (not shown), and outputs a signal for detecting the temperature of the outside air to the external device.

In addition, the tin plating for improving corrosion resistance is given to the part exposed in the connector part 21C in the terminal 14 (including the fourth terminal 14b). Further, the protruding shape provided on the outer side of the connector portion 21C is for preventing erroneous insertion of connection terminals for other sensors or other types of temperature sensors into the connector portion 21C. These protrusion shapes are provided so as to match the shape of the connection terminal (connector) of the external device inserted into the connector portion 21C.

The clamp fitting part 23 is a structural part for fitting a clamp member 30 manufactured separately from the body part 21, the support part 22, and the clamp fitting part 23 that are integrally formed. The clamp fitting portion 23 has a structure such as a locking claw 23a for preventing the fitted clamp member 30 from being detached due to vibration or wind and rain during traveling.

Of course, a structure corresponding to the clamp member 30 may be integrally formed together with the body portion 21 and the support portion 22. In addition, after the body part 21, the support part 22, and the clamp fitting part 23 are primarily molded, the shape corresponding to the clamp member 30 may be further molded to be integrated. In this case, the locking claw 23a is unnecessary. The support part 22 is a structural part for supporting the body part 21 to the clamp fitting part 23. Note that a direction perpendicular to the axial direction and directed from the body portion 21 toward the clamp fitting portion 23 is a vertical direction for the following description, and in this vertical direction, the body portion 21 is the clamp fitting portion 23. It is assumed that it is in the upward direction.

The clamp member 30 includes a temperature sensor end portion and a vehicle end portion (both not shown), and the temperature sensor end portion is fitted into the clamp fitting portion 23, whereby the clamp member 30 and the temperature sensor are provided. 100 is united. Moreover, the clamp member 30 is fixed to the vehicle by fitting the end portion for the vehicle into a fitting hole provided in a front bumper or the like of the vehicle. That is, in the temperature sensor 100 in which the end portion for the temperature sensor is fitted into the clamp fitting portion 23 and integrated with the clamp member 30, the end portion for the vehicle of the clamp member 30 is further inserted into the fitting hole provided in the front bumper Fr or the like. By being fitted, it is fixed to the vehicle. And if the temperature sensor 100 is installed in the location which touches outside air, such as the front bumper Fr of a vehicle, the resistance value of the thermistor element 11 will change with the temperature of outside air, and it can detect the temperature of outside air from the resistance value. .

Hereinafter, a method for manufacturing the temperature sensor 100 according to the present embodiment will be described with reference to the drawings. In manufacturing the temperature sensor 100, first, the first terminal of the lead wire 13 for applying a voltage to the thermistor element 11 and the thermistor element 11 are electrically connected by welding or the like. Then, the thermistor element 11 is coated with the epoxy resin 12 so as to include a part of the lead wire 13 to form the temperature sensing part 10. Furthermore, the second terminal 13b not connected to the thermistor element 11 of the lead wire 13 is electrically and mechanically connected to the third terminal 14a of the terminal 14 by welding or the like, so that one structure shown in FIG. 101 is generated.

Then, the structure 101 is set in an injection mold, and the process proceeds to a process of injecting a molten resin (this is an injection molding process). The body part 21, the support part 22, and the clamp fitting part 23 are integrally formed by cooling and solidifying the molten resin injected into the mold, and the temperature-sensitive part 10 and the like are formed on the body part 21. The housed temperature sensor 100 can be obtained.

Here, before describing the second mold 50A used in the injection molding process according to the present embodiment, the first mold 50B used in the injection molding process in the comparative configuration corresponding to the prior art will be described, and the problem in the comparative configuration Let me reiterate.

FIG. 4 shows a cross-sectional view of a state in which the structure 101 is set in the first mold 50B used in the injection molding process with the comparative configuration, and FIG. 5 shows a dashed line 5-5 in FIG. A schematic diagram of a cross section is shown. The first mold 50B is a composite body in which various mold parts are combined, and mainly includes a base mold 51, a first head side mold 52, and a connector molding mold 55. Of course, the mold parts constituting the first mold 50B may be further finely divided. For example, the base mold 51 may be divided into two or more in order to take out the finished product. The structure for taking out the finished product may be designed as appropriate and is omitted here.

However, when the base mold 51 is divided in order to take out the finished product, a rubber plate is arranged on the combination surface so that no gap is generated on the contact surface when the divided mold parts are combined. For example, a structure that keeps hermeticity is used. This is to prevent an unintended gap between the molds from flowing into the gap and causing a defective shape such as a burr in the finished product.

The position of the gate G for injecting the molten resin into the space formed inside the first mold 50B may be designed as appropriate. The position of the gate G may be determined in consideration of the flow of the dissolved resin and the like. In this embodiment and the comparative configuration, as shown in FIGS. 4 and 5, on both sides of the space in which the connector portion 21 </ b> C is formed. Provide. The side here is a direction perpendicular to the axial direction and the vertical direction.

In addition, the space formed inside the first mold 50B has a shape corresponding to the body part 21, the support part 22, and the clamp fitting part 23 described above. Therefore, among the spaces formed in the first mold 50B, the space corresponding to the body portion 21 corresponds to the body portion space C21, the space corresponding to the support portion 22 corresponds to the support portion space C22, and the clamp fitting portion 23. This space is referred to as a clamp fitting portion space C23. In the body part space C21, an end corresponding to the head part 21H is defined as a head side end, and an end corresponding to the connector part 21C is defined as a connector side end. Here, the body part space C21 having a columnar shape corresponding to the body part 21 corresponds to the cavity, the head side end part corresponds to the first end part, and the connector side end part corresponds to the second end part. . Hereinafter, since the difference between the second mold 50A used in the present embodiment and the first mold 50B used in the comparative configuration is provided in a part that forms the body part space C21, this body part is mainly used. The mold part that forms the space C21 will be described.

The connector molding die 55 is a mold part for molding the connector portion 21C, which is disposed at the connector side end portion, and has a shape that matches the inner surface shape of the connector portion 21C. Further, a terminal insertion port 55a is provided at the distal end portion of the connector molding die 55. By inserting the terminal 14 portion of the structure 101 into the terminal insertion port 55a, the structure 101 is moved to the first mold. Fix to 50B. Note that the fixed position of the structure 101 at this time is the position of the structure 101 in the body portion 21 designed in advance. For example, the structure 101 is fixed along the axis of the cylindrical body space C21.

Further, the connector molding die 55 is combined with the base die 51 so that a minute gap A5 is generated between the connector molding die 55 and the base die 51. In the process in which the molten resin is injected from the gate G and the connector portion 21C is formed, the gas existing in the space from the gate G to the end of the connector portion 21C passes through the minute gap A5 to form the first mold. 50B is extracted outside. Therefore, this minute gap A5 becomes a gas vent passage provided at the connector side end. In this case, the gas vent passage corresponds to a connector-side gas vent passage. The minute gap serving as the gas vent passage may be designed with a size (for example, 0.1 mm) that allows a gas such as air to pass but does not allow the dissolved resin to pass therethrough and considers the viscosity of the dissolved resin. .

1st head side metal mold | die 52 is a metal mold | die for shape | molding the end surface of the head part 21H. The first head side mold 52 is combined with the base mold 51 so that a minute gap A1 for venting gas is generated between the first head side mold 52 and the base mold 51. In this case, the gap A1 corresponds to the first head side gas vent passage. In the process in which the molten resin flows from the gate G to the head side end, the gas existing in the space from the gate G to the head side end is extracted outside through the first head side gas vent passage A1. .

When the structural body 101 is set in the first mold 50B and the base mold 51, the first head side mold 52, and the connector molding mold 55 are combined, so-called mold clamping is completed, and from the gate G, the first mold is completed. The dissolved resin is poured into the mold 50B.

The process in which the dissolved resin flows through the body part space C21 of the first mold 50B used in the comparative configuration will be described with reference to FIG. Here, polybutylene terephthalate (PBT) is used as the dissolved resin, but the invention is not limited to this. Known resins such as polyphenylene sulfide (PPS) and polyamide (PA) may be used. Further, the PBT resin used as the dissolving resin is mixed with glass fibers at a predetermined ratio (for example, 20%) in order to ensure strength.

(A), (B), and (C) of FIG. 6 are schematic diagrams showing the process of injecting the molten resin from the gate G into the first mold 50B in chronological order. As shown in FIG. 6A, the molten resin injected from the gate G collides with the connector molding die 55 and develops along the connector molding die 55 and the base die 51. Since the gate G is disposed in the vicinity of the space where the connector portion 21C is molded, the molten resin is filled into the space of the connector portion 21C at an earlier stage than the head portion 21H is shaped. Further, the melted resin that flows toward the head side end portion as viewed from the gate G flows along the outer periphery of the body portion space C21. 6B and 6C show a process in which the space from the gate G to the head side end is filled with the dissolved resin.

By the way, in the structure 101, the lead wire 13 and the terminal 14 are linear members, whereas the temperature sensing unit 10 is in the form of water droplets. Therefore, when the area that the structure 101 occupies the body part space C21 in a cross section perpendicular to the axial direction is viewed, the area that the temperature sensing unit 10 occupies the body part space C21 is larger than the lead wire 13 and the terminal 14. Therefore, in the space from the gate G to the head side end portion of the dissolved resin, the narrow portion R10 formed in the vicinity of the temperature sensing portion 10 has a narrow space where the dissolved resin and gas can flow compared to the other portions. It has become.

The melted resin flows around from the outer periphery of the body space C21 along the base mold 51. Therefore, the narrow portion R10 is further narrowed with the inflow of the dissolved resin. When the narrow portion R10 becomes narrower, the gas remaining in the space from the gate G to the narrow portion R10 becomes more difficult to escape from the gate G side of the narrow portion R10 to the end portion on the head portion 21H side.

Returning to FIG. 6 again, the state in the body space C21 at the time when the molten resin is further injected from the state (A) is shown in (B). FIG. 6B shows a state in which the narrow portion R10 is blocked with the melted resin for the above-described reason before the gas completely escapes from the body space portion from the gate G to the narrow portion R10.

Then, (C) shows the case where the molten resin is further injected from the gate G. The gas remaining in the space from the temperature sensing portion 10 to the end of the head portion is pushed by the dissolved resin passing through the narrow portion R10 and discharged through the first head-side gas vent passage A1, and the temperature is sensed. The molten resin fills the space from the portion 10 to the end portion on the head portion 21H side.

However, since the gas in the space from the gate G to the temperature sensing unit 10 is not completely removed, the residual gas causes a void 60. That is, in the comparative configuration, the speed at which the dissolved resin reaches the narrow portion R10 is higher than the speed at which the gas escapes from the space from the gate G to the narrow portion R10. Therefore, as shown in FIG. 60 may occur.

In contrast to the first mold 50B used in the comparative configuration described above, the second mold 50A shown in FIGS. 7 and 8 is used in the present embodiment. FIG. 7 shows a cross-sectional view of the second mold 50A in a state where the structure 101 is set, and FIG. 8 shows a cross-sectional view taken along one-dot chain line 8-8 in FIG. FIG. 7 and FIG. 8 correspond to FIG. 4 and FIG. 5 for explaining the comparative configuration, respectively. Parts corresponding to each other in the comparative configuration and the present embodiment are denoted by the same reference numerals for the sake of simplicity. Except for the point that the mold to be used is changed from the first mold 50B to the second mold 50A, the procedure of the injection molding process (mold clamping, injection, cooling, etc.) is the same as the conventional one.

The second mold 50A in the present embodiment is a composite body in which various mold parts are combined in the same manner as the first mold 50B, and includes a base mold 51, a third head side mold 54, and a second head. A side mold 53, a first head side mold 52, and a connector molding mold 55 are provided. The first head side mold 52 in this embodiment corresponds to the first head side mold 52 in the conventional configuration. The connector molding die 55 is the same as the first die 50B having a comparative configuration.

The third head side mold 54, the second head side mold 53, and the first head side mold 52 have a nested structure as shown in FIG. 9, and a minute gap is generated between the respective molds. Thus, the base mold 51 is combined. FIG. 10 is an enlarged view of the end portion on the head portion 21H side in a state where the third head side die 54, the second head side die 53, the first head side die 52, and the base die 51 are combined. Show.

As shown in FIGS. 9 and 10, a small gap provided between the base mold 51 and the third head side mold 54 passes through the third head side degassing passage A3, the third head side mold 54, and the like. A minute gap provided between the second head side mold 53 is defined as a second head side gas vent passage A2. Further, a minute gap provided between the second head side mold 53 and the first head side mold 52 is defined as a first head side degassing passage A1.

Here, returning to FIG. 9, the combined portion of the base mold 51 and the third head side mold 54 will be described in detail. As shown in FIG. 9, the diameter D3b of the inner circumference of the annular plane 54F perpendicular to the axis of the body part space C21 in the third head side mold 54 is perpendicular to the axis of the body part space C21 in the base mold 51. It is smaller than the diameter D3a of the inner circumferential circle of the annular plane 51F. Therefore, between the small diameter cylindrical surface 54S connected to the inner circumferential circle of the annular flat surface 54F of the third head side mold 54 and the large diameter cylindrical surface 51S connected to the inner circumferential circle of the annular flat surface 51F of the base mold 51. Are stepped in a direction perpendicular to the axis.

The base mold 51 and the third head side mold 54 are combined so that a minute gap is generated between the annular plane 51F and the annular plane 54F. That is, the gap generated at the step portion between the small-diameter cylindrical surface 54S and the large-diameter cylindrical surface 51S becomes a gas extraction port in the third head-side gas vent passage A3. The gas that has entered the third head side gas vent passage A3 from the stepped portion is connected to the surface connected to the outer peripheral circle of the annular flat surface 54F of the third head side mold 54 and the outer peripheral circle of the annular flat surface 51F of the base die 51. It goes out of the 2nd metal mold | die 50A through the clearance gap provided between the surface to perform.

Further, the combined portion of the third head side mold 54 and the second head side mold 53 is similarly provided with a step portion, and includes a second gas vent passage A2 having the step portion as a gas outlet. I am letting. In addition, by providing such a step portion in the vicinity of the head side end portion of the second mold 50A, the step portion is also provided in the head portion 21H of the temperature sensor 100 which is a finished product.

As described above, in the second mold 50A, the first head side mold 52, the second head side mold 53, and the third head side mold 54 are separated from each other by a minute gap. By combining with the base mold 51 so as to occur, it is possible to increase the gas vent passage between the gate G and the end on the head portion 21H side as compared with the comparative configuration.

In the first mold 50B of the comparative configuration, the only path through which gas escapes from the gate G to the head side end is the first head side gas vent passage A1 provided at the head side end. However, when the second mold 50A of the present embodiment is used, in addition to the first head side gas vent passage A1 provided at the head side end portion, two gates are further provided between the gate G and the head side end portion. A second gas vent passage A2 and a third gas vent passage A3 are provided.

Therefore, by using the second mold 50A, the gas in the space from the gate G to the narrow portion R10 is more externally introduced in the process of injecting the molten resin from the gate G than in the comparative configuration using the first mold 50B. It can make it easy to slip through. And possibility that a void will generate | occur | produce in the space from the gate G to the narrow part R10 can be reduced.

Incidentally, in order to reduce the possibility that voids are generated in the space from the gate G to the narrow portion R10, for example, a method of changing the position of the gate G is conceivable as another solution. However, if the position of the gate G is changed, the flow of the molten resin flowing from the gate G into the body part space C21 also changes, and there is a possibility that a turbulent flow of the molten resin occurs. Since the PBT resin and the glass fiber in the melted resin have different flow speeds, when turbulent flow occurs, the glass fiber may solidify and float in one place, so-called glass floating state may occur. .

In addition, the flow of the dissolved resin flowing from the gate G into the body part space C21 changes, so that the structure 101 fixed to the body part space C21 by the flowing pressure of the dissolved resin becomes the axis of the body part space C21. There is a risk of dislodging. When the structure 101 is molded at a position deviated in any direction from the axis, the thickness of the resin in the vicinity of the temperature sensitive portion 10 in the deviated direction becomes smaller than the design value, and as a result, the strength is insufficient. Such a failure may occur.

In other words, by changing the position of the gate G, even if the possibility of voids occurring in the space from the gate G to the narrow portion R10 can be reduced, there are different types of defects such as glass floating and insufficient strength. May occur.

Further, if the speed at which the molten resin reaches the narrow portion R10 is lower than the speed at which the gas in the space from the gate G to the narrow portion R10 escapes, voids may be generated in the space from the gate G to the narrow portion R10. Can be reduced. Therefore, as another solution, a method of reducing the injection speed of the dissolved resin is also conceivable. However, when the injection speed is lowered, the time required for the melted resin to fill the body portion space C21 increases, and thus the production efficiency per hour is lowered.

In view of these circumstances, as in the present embodiment, a configuration in which a gas vent passage is additionally provided between the gate G and the head side end portion allows the gate G to be changed without changing the gate position or the injection speed. The possibility that voids are generated in the space from to the temperature sensing unit 10 can be reduced.

In general, when a gas vent passage is provided, the minute gap serving as the gas vent passage is small enough to prevent the dissolved resin from passing therethrough. The trace of remains in the finished product.

However, as in the present embodiment, the cross-sectional area of the portion corresponding to the head portion 21H in the body portion space C21 is reduced in a stepped manner toward the head side end portion, and the gas vent structure first in the step portion. A head-side gas vent passage A1 and a second head-side gas vent passage A2 are provided. Thereby, the trace of the degassing structure in the finished product can be made inconspicuous, and the merchantability can be maintained.

The second mold 50A used in the manufacturing method of the present embodiment includes the first head side gas vent passage A1, the second head side gas vent passage A2, and the third head between the gate G and the head side end. Although it was set as the structure provided with three degassing passages of the side degassing passage A3, it is not restricted to this. There may be two degassing passages or four or more.

Of the gas vent passages provided between the gate G and the head side end, the one closest to the gate G (that is, the third head side gas vent passage A3) is the center of the temperature sensing unit 10 and the head portion 21H side. Although it was set as the structure provided between the edge parts, it is not restricted to this. The additional gas vent passage may be provided between the gate G and the head side end, and may be provided on the gate G side with respect to the temperature sensing unit 10 as shown in FIG. However, as the gas vent passage is closer to the gate G, it is covered with the molten resin at an earlier time, and the function of venting gas is impaired. Therefore, in order to operate the gas vent passage more effectively, the gate G It is desirable to be away from the vicinity.

On the other hand, there may be a case where there is a greater effect of degassing if there is a degassing passage near the space where you want to escape gas. As in the present embodiment, by adding a gas vent passage in the vicinity of the narrow portion R10 by the temperature sensing unit 10, it is expected that the gas hardly remains in the vicinity of the narrow portion R10.

Although the present disclosure has been described based on the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more or less, are within the scope and spirit of the present disclosure.

Claims

For manufacturing a temperature sensor for forming a housing (21) that houses a structure (101) in which a temperature sensing part (10), a lead wire (13), and a terminal (14) are connected in a straight line in this order. Mold (50A),
A columnar cavity (C21) that houses the structure, with the direction in which the temperature sensing unit, the lead wire, and the terminal are connected as an axial direction,
A first degassing passage that communicates the cavity with the outside of the mold in order to vent the gas in the cavity to the first end of the cavity that houses the temperature sensing portion of the structure. (A1),
The cavity is disposed at a second end which is an end opposite to the first end, and the terminal that is not connected to the lead wire is inserted into the terminal to insert the structure into the structure. A structure support (55a) for holding in place in the cavity;
A gate (G) formed between the second end portion and the temperature sensing portion and injecting resin into the cavity;
For producing a temperature sensor, a second gas vent passage (A3) that communicates between the cavity and the outside of the mold is provided between the first end and the gate to allow gas in the cavity to escape. Mold.
In claim 1,
The second gas vent passage is a mold for manufacturing a temperature sensor provided between the first end portion and an end portion of the temperature sensing portion on the second end side.
In claim 2,
The second gas vent passage is provided between the first end of the temperature sensing portion on the first end side and the second end of the temperature sensing portion on the second end side. Mold.
In any one of Claims 1-3,
The mold includes a step portion between the gate and the first end,
The stepped portion is connected to an annular plane perpendicular to the axis of the cavity, an inner circumference of the annular plane, and is located on the first end side with respect to the annular plane, and the annular plane Is formed by a large-diameter cylindrical surface with a diameter larger than the diameter of the inner circumferential circle of the annular plane,
A mold for producing a temperature sensor, wherein a gap is formed between the annular plane and the large-diameter cylindrical surface, and the second gas vent passage is a passage partially including the gap.
In claim 4,
The mold includes the stepped portion at a plurality of locations,
A mold for manufacturing a temperature sensor in which a plurality of the second gas vent passages each including a gap formed in each stepped portion are formed.
6. The method for manufacturing a temperature sensor according to claim 1, wherein the housing is injection-molded by injecting a molten resin into the cavity from the gate of the mold.
A temperature sensor (10), a lead wire (13), and a structure (101) in which a terminal (14) is integrated in a straight line in this order;
A cylindrical housing (21) that houses the structure and has an axial direction in which the temperature sensing unit, the lead wire, and the terminal are connected;
A temperature sensor comprising a step portion at a first end portion on the side of housing the temperature sensing portion among the end portions of the housing.