Heater member for thermostat and manufacturing method thereof

Abstract

To provide a heater member for thermostat capable of forming a lead wire short, and insert-molding a connector together with a heater, while preventing the breakage of the heater at manufacturing, and a manufacturing method thereof.SOLUTION: A heater member for thermostat is equipped with a rod-shaped heater 5 that is disposed in a piston provided in a thermostat device, a lead 9 wire drawn from the heater, a terminal pin 8 to which one end of the lead wire is connected, and a connector portion 6 having a rear end surface of the heater, the lead wire, and the terminal pin arranged therein. The rear end surface of the heater is disposed in a hollow portion formed in the connector portion, and does not contact with resin forming the connector portion.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a heater member for a thermostat and a manufacturing method thereof, and more particularly to a heater member for a thermostat that is capable of insert-molding a connector together with the heater while preventing damage to the heater during manufacturing, and a manufacturing method thereof. [Background technology]

[0002] For example, a thermostat device that is installed in the cooling water system of an automobile engine or the like and performs variable water temperature control contains wax (thermal expansion body) that expands and contracts in response to temperature changes in the cooling water flowing through the circulation path.The thermostat device opens and closes a valve body using the volume change that accompanies the expansion and contraction of the wax to maintain the cooling water at a specified temperature.

[0003] In some thermostat devices of this type, heater means for controlling the temperature of the thermal expansion body is provided inside a case in which wax is sealed, and the volume change of the wax can be controlled by the heat generated by this heater means.

[0004] Conventionally, this type of electronically controlled thermostat device has a heater inserted inside a piston formed by a thermoelement. When the heater is turned on, the thermal expansion body inside the thermoelement is heated, activating the thermoelement to open and close the valve.

[0005] In addition, in this type of electronically controlled thermostat device, the lead wire extension from the heater is connected by soldering or the like to a connector terminal of a resin connector assembled from the outside of the device housing, and then molded with a resin material.

[0006] However, in the conventional configuration, the casing of the resin connector is not fixed in the rotational direction relative to the device housing, which poses problems such as the risk of the lead wires twisting and shorting out. Furthermore, if the resin material comes into contact with the rear end surface of the heater during molding with the resin material, there is a risk that the heater will be damaged by molding pressure.

[0007] In order to address such issues, Patent Document 1 discloses a heater member configuration that includes a pair of insulating rod pieces 80 configured to clamp a heater 70 at its tip and to clamp a pair of lead wires 71, 72 drawn from the heater while maintaining an insulated state, as shown in FIG. 7, and a connector member 81 that is assembled to the part of these insulating rod pieces 80 opposite the heater clamping part and is assembled and fixed to the outside of the device housing.

[0008] The connector member 81 has connector terminals 85, 86 at its inner end which have a pair of lead end connection pieces 85a, 86a to which the lead wires 71, 72 are connected, and is also provided with an engagement recess 88 which engages with an engagement protrusion 87 for preventing twisting provided on the part of the insulating rod piece 80 opposite the heater clamping portion.

[0009] With such a heater member, the heater 70 and a pair of lead wires 71, 72 are sandwiched between a pair of insulating rod pieces 80, and a piston 60 having a bottomed cylindrical shape is provided on the outside to cover them, thereby reducing the risk of the ceramic heater cracking, the lead wires breaking, bending (twisting), etc.

[0010] However, in the configuration disclosed in Patent Document 1, the lead wires 71 and 72 are long, which increases the overall length of the heater member, and thus poses a problem in that it cannot contribute to miniaturization of the thermostat device. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] JP 2017-133664 A Summary of the Invention [Problem to be solved by the invention]

[0012] In order to eliminate the problems of lead wire length and twisting, it is possible to directly join the terminal and heater without using lead wires. In this case, for example, the terminal is insert molded to create a connector, and the terminal of the ceramic heater is laser joined to the terminal. However, such a configuration has problems such as difficulty in process management of the laser joining and poor quality of the joined part, and there is a risk that spatter burrs may come into contact with the piston during joining, which may deteriorate the insulation resistance and cause a decrease in yield.

[0013] The present invention has been made with attention to the above-mentioned points, and aims to provide a heater component for a thermostat and a manufacturing method thereof that can form short lead wires and insert mold a connector together with the heater while preventing damage to the heater during manufacturing. [Means for solving the problem]

[0014] In order to solve the above-mentioned problems, a heater member for a thermostat according to the present invention is a heater member provided in a thermostat device, and includes a rod-shaped heater disposed in a piston provided in the thermostat device, a lead wire drawn from the heater, a terminal pin to which one end of the lead wire is connected, and a connector portion that has a rear end surface of the heater, the lead wire, and the terminal pin disposed therein. , heater protection unit and a rear end surface of the heater is disposed in a hollow portion formed in the connector portion and is in contact with a resin forming the connector portion. the heater protection portion covers a radial circumferential surface of the heater from the middle to the rear end side of the heater with resin and is formed integrally with the connector portion. It is characterized by: It is preferable that the heater protection section be formed integrally with the connector section and cover the radial peripheral surface of the heater with resin. It is also preferable that the lead wire and the terminal pin are joined so as to be electrically connected to each other, for example, by crimping.

[0015] According to the heater member for a thermostat configured in this manner, the rear end surface of the heater is disposed in the hollow portion during insert molding of the heater and the connector portion, and does not come into contact with the resin, so that the heater can be protected from the molding pressure (injection pressure, mold pressure) of the resin, and the occurrence of damage to the heater can be prevented. In addition, since the radial peripheral surface of the heater is covered by the heater protection portion, the heat retention performance can be improved. In addition, since the length of the lead wire can be shortened, the overall length of the heater member can be kept short, which can contribute to the miniaturization of the product. In addition, since the terminal pin, the lead wire, the connector, and the heater can be insert molded, the manufacturing time can be shortened and the cost can be reduced. In addition, the variation in dimensional molding can be suppressed, and the yield can be improved. In addition, since the lead wire is disposed in the connector member, twisting of the lead wire can be prevented. Furthermore, when the connection between the terminal pin and the lead wire is performed by crimping, the equipment costs can be reduced compared to laser joining, and the problem of spatter burrs occurring during laser joining can be avoided.

[0016] In order to solve the above-mentioned problems, the manufacturing method of a heater member for a thermostat according to the present invention is a manufacturing method of a heater member provided in a thermostat device, and includes a step of connecting a lead wire drawn from a rod-shaped heater arranged inside a piston to a terminal pin, and a step of insert-molding a connector part so that the terminal pin connected via the lead wire and a rear end face of the heater are arranged inside the connector part, and in the insert-molding step, a mold is used in which a hole and an internal space communicating with the hole are formed in the connector part, and the rear end face of the heater is arranged in the portion where the hole is formed. Further, a heater protection portion is formed by covering a radial peripheral surface of the heater from the middle to the rear end side of the heater with resin and being integrally formed with the connector portion. It is characterized by the fact that In the insert molding step, it is preferable to form a heater protection portion that is integral with the connector portion and that covers a radial peripheral surface of the heater with resin.

[0017] According to this method, when the heater and the connector part are insert molded, the rear end surface of the heater is disposed in the hollow part and does not come into contact with the resin, so that the heater can be protected from the molding pressure (injection pressure, mold pressure) of the resin, and the heater can be prevented from being damaged. In addition, the heater's radial circumferential surface is covered by the heater protection part, so that the heat retention performance can be improved. In addition, the length of the lead wire can be shortened, so that the overall length of the heater member can be kept short, which contributes to the miniaturization of the product. In addition, the terminal pin, the lead wire, the connector, and the heater can be insert molded, so that the manufacturing time can be shortened and the cost can be reduced. In addition, the variation in dimensional molding can be suppressed, and the yield can be improved. In addition, the lead wire is disposed in the connector member, so that the twisting of the lead wire can be prevented. Furthermore, when the connection between the terminal pin and the lead wire is performed by crimping, the equipment costs can be reduced compared to laser joining, and the problem of spatter burrs occurring during laser joining can be avoided. Effect of the Invention

[0018] According to the present invention, it is possible to provide a heater member for a thermostat, which prevents damage to the heater during manufacturing, allows the lead wires to be short, and enables a connector to be insert molded together with the heater, and a manufacturing method thereof. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a cross-sectional view of a thermostat device equipped with a thermostat heater member (first embodiment) according to the present invention. [Diagram 2] FIG. 2 is a perspective view of the heater member 1. As shown in FIG. [Diagram 3] FIG. 3(a) is a front view of the heater member, and FIG. 3(b) is a side view (partially cross-sectional view) of the heater member. [Figure 4] 4(a) and (b) are side views for explaining the connection structure between the terminal pin 8 and the terminal portion 5a of the heater 5. FIG. [Diagram 5]FIG. 5 is a cross-sectional view of a thermostat device equipped with a thermostat heater member (second embodiment) according to the present invention. [Figure 6] FIG. 6(a) is a front view of the heater member 1, and FIG. 6(b) is a side view (partial cross-sectional view) of the heater member 1. [Figure 7] FIG. 7 is a cross-sectional view of a conventional heater member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] (First embodiment) DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a heater member for a thermostat according to the present invention will now be described with reference to the drawings, in which: Fig. 1 is a cross-sectional view of a thermostat device equipped with a heater member for a thermostat according to the present invention. The electronically controlled thermostat device 10 shown in FIG. 1 is provided, for example, in an engine cooling water system, and is attached to an intersection between a cooling water passage on the radiator side and a bypass passage from the engine outlet side, and controls the cooling water temperature reaching the engine inlet by selectively switching the flow of cooling water in the first and second fluid flow paths formed by these passages.

[0021] The thermostat device 10 comprises a piston 18 having a generally cylindrical shape with a bottom, suspended within the device housing 11, and a thermoelement 17 fitted on the outside of the piston 18 so as to be slidable in the axial direction. A main valve body 15 for controlling the opening and closing of a fluid passage formed within the device housing 11 is provided at the upper axial portion of the thermoelement 17.

[0022] Here, a thermal expansion body such as wax is enclosed within the thermoelement 17, and the tip of the piston 18 is disposed facing the thermal expansion body, and the temperature can be controlled by a heater 5 provided within the piston 18.

[0023] In addition, in this electronically controlled thermostat device 10, a spring 16 and a spring retainer 16a are provided to bias the main valve body 15, and a second valve body that serves as a bypass valve and a bypass spring, etc. are also provided, but since the configurations of these are well known, specific illustrations and explanations will be omitted here.

[0024] In the drawing, reference numeral 12 denotes an inlet for cooling water from the radiator, reference numeral 13 denotes an inlet on the bypass circuit side, reference numeral 13a denotes an inlet portion from the inlet on the bypass circuit side to the downstream side of the main valve body 15, and reference numeral 14 denotes a passage opening leading to the inlet portion of the engine. Reference numeral 6 denotes a connector portion for connecting the heater 5 provided inside the piston 18 to the outside.

[0025] The heater member according to the present invention is a member including the heater 5 and the connector portion 6, and will be denoted by the reference numeral 1 below. FIG. 2 is a perspective view of the heater member 1, FIG. 3(a) is a front view of the heater member 1, and FIG. 3(b) is a side view (partially cross-sectional view) of the heater member 1. The heater member 1 includes the heater 5 in the form of a flat rod made of ceramic, and the connector portion 6 which is formed by resin molding.

[0026] 3(b), a pair of terminal pins 8 are fixedly disposed within the connector portion 6. The terminal pins 8 are electrically connected to the terminal portion 5a of the heater 5 via lead wires 9. 4(a) and (b) are side views for explaining the connection structure between the terminal pin 8 and the terminal portion 5a of the heater 5. FIG. As shown in Fig. 4(a), a crimping portion 3 is provided at the rear end of the terminal pin 8, and an end of a lead wire 9 drawn from the terminal portion 5a of the heater 5 is disposed thereon. Then, as shown in Fig. 4(b), the end of the lead wire 9 is crimped at the crimping portion 3, and the lead wire 9 is electrically connected and joined to the terminal pin 8.

[0027] Further, the rear end surface 5b of the heater 5 is disposed within the connector portion 6, but this rear end surface 5b is disposed in a hollow portion within the connector portion 6 so as not to come into contact with the resin forming the connector portion 6. As shown in the perspective view of Fig. 2, a hole 6b that communicates with the hollow portion within the connector portion 6 is formed in approximately the center of the flange portion 6a from which the heater 5 extends, and this hole 6b is formed with a diameter large enough not to come into contact with the heater portion 5. In other words, the rear end surface 5b of the heater 5 is disposed in the hollow portion within the connector portion 6 in a state where it does not come into contact with the resin.

[0028] With this configuration, the molding resin does not come into contact with the rear end surface 5b of the heater 5 during insert molding of the connector portion 6, and damage to the heater 5 due to molding pressure can be prevented.

[0029] To manufacture such a heater member 1, first, as shown in Figs. 4(a) and 4(b), the terminal pin 8 and the lead wire 9 drawn out from the heater 5 are connected by crimping. Next, in order to form the connector portion 6 from resin, the heater 5 and the terminal pin 8 connected via the lead wire 9 are placed in a mold (not shown) and insert molded. At this time, the mold is formed so that the hole 6b and a hollow portion communicating therewith are formed in the connector portion 6, and the rear end surface 5b of the heater 5 is placed in the portion where the hole 6b is formed, so that the molding resin does not come into contact with the rear end surface 5b of the heater 5, and it is possible to avoid the effect of the molding pressure of the resin on the heater 5.

[0030] According to the heater member 1 for a thermostat configured in this manner, when the heater 5 and the connector portion 6 are insert molded, the rear end surface 5b of the heater 5 is disposed in the hollow portion and does not come into contact with the resin, thereby protecting the heater 5 from the molding pressure of the resin (injection pressure, mold pressure) and preventing damage to the heater 5. In addition, since the length of the lead wire 9 can be shortened, the overall length of the heater member 1 can be kept short, which contributes to the miniaturization of the product. Furthermore, since the terminal pin 8, the lead wire 9, the connector 6, and the heater 5 can be insert molded, the manufacturing time can be shortened and the cost can be reduced. Furthermore, the variation in dimensional molding can be suppressed, and the yield can be improved. Furthermore, since the lead wire 9 is disposed inside the connector member 6, twisting of the lead wire 9 can be prevented. Furthermore, when the connection between the terminal pin 8 and the lead wire 9 is performed by crimping, the equipment costs can be reduced compared to laser joining, and the problem of spatter burrs occurring during laser joining can be avoided.

[0031] In the above embodiment, the terminal pin 8 and the lead wire 9 are joined by crimping, but the present invention is not limited to this form, and the terminal pin 8 and the lead wire 9 may be joined by laser joining or soldering.

[0032] Second Embodiment Next, a second embodiment of a heater member for a thermostat according to the present invention will be described with reference to the drawings. Fig. 5 is a cross-sectional view of a thermostat device equipped with a heater member for a thermostat according to the present invention (second embodiment). Fig. 6(a) is a front view of the heater member 1, and Fig. 6(b) is a side view (partial cross-sectional view) of the heater member 1. In the description of this second embodiment, the same members as those in the above-mentioned first embodiment are indicated by the same reference numerals, and detailed description thereof will be omitted.

[0033] The second embodiment differs from the first embodiment in that a heater protection part 7 is provided so as to cover the radial circumferential surface of the elongated heater 5 from the middle of the heater 5 to the rear end side (the connector part 6 side) as shown in Figures 5, 6(a) and (b).

[0034] The heater protection part 7 is formed integrally with the connector part 6. That is, in the insert molding of the connector part 6, the heater protection part 7 is formed of resin so as to cover the radial circumferential surface of the heater 5. When the heater protection part 7 is formed, the impact of the injection pressure is received by the mold, so that the pressure is not directly applied to the heater 5 and is weakened. In addition, although the dwell pressure is applied from the radial direction (horizontal direction), it is received on both sides of the plane, so that it is offset and weakened. In this manner, in the second embodiment of the present invention, the radial circumferential surface of the heater 5 is covered by the heater protection portion 7, so that the heat retention performance can be improved. [Explanation of symbols]

[0035] 1 Heater parts for thermostats 5 Heater 6 Connector part 6b hole 7 Heater protection unit 8 Terminal Pins 9 Lead Wire

Claims

1. A heater member provided in a thermostat device, the thermostat device includes a rod-shaped heater disposed within a piston provided in the thermostat device, a lead wire drawn from the heater, a terminal pin to which one end of the lead wire is connected, a connector portion in which a rear end surface of the heater, the lead wire, and the terminal pin are disposed, and a heater protection portion; a rear end surface of the heater is disposed in a hollow portion formed in the connector portion and is not in contact with a resin forming the connector portion; The heater member for a thermostat, wherein the heater protection portion covers a radial peripheral surface of the heater from a middle of the heater to a rear end side with resin and is formed integrally with the connector portion.

2. 2. The heater member for a thermostat according to claim 1, wherein the lead wire and the terminal pin are joined so as to be electrically connected to each other.

3. 3. The heater member for a thermostat according to claim 2, wherein the lead wire and the terminal pin are connected by crimping.

4. A manufacturing method of a heater member provided in a thermostat device, comprising: a step of connecting a lead wire drawn from a rod-shaped heater disposed inside the piston to a terminal pin; and insert-molding a connector portion so that a terminal pin connected via the lead wire and a rear end surface of the heater are disposed therein, In the insert molding step, A manufacturing method for a heater member for a thermostat, characterized in that a mold is used in which a hole and an internal space communicating with the hole are formed in the connector portion, the rear end face of the heater is positioned in the hole formation portion, and a heater protection portion is formed integrally with the connector portion while covering the radial circumferential surface of the heater from the middle to the rear end side with resin.

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