HEATER MEMBER FOR THERMOSTAT AND MANUFACTURING METHOD THEREFOR

Abstract

Provided are a heater member for a thermostat and a manufacturing method therefor which enables the formation of a short lead wire and insert-molding of a connector together with a heater while preventing the heater from being damaged during manufacturing. The heater member includes a bar-like heater arranged in a piston provided for a thermostat device; a lead wire pulled out from the heater; a terminal pin connected to one end of the lead wire; and a connector portion having a back end surface of the heater, the lead wire, and the terminal pin arranged inside thereof. The back end surface of the heater is arranged in a hollow portion formed in the connector portion without being in contact with resin forming the connector portion.

Claims

1.-6. (canceled)

7. A heater member to be provided on a thermostat device, comprising: a bar-like heater disposed in a piston provided in the thermostat device, a lead wire drawn out from the heater, a terminal pin to which an end of the lead wire is connected, and a connector portion in which a rear end face of the heater, the lead wire, and the terminal pin are provided, wherein the rear end face of the heater is disposed in a hollow portion formed in the connector portion and is not in contact with a resin material forming the connector portion.

8. The heater member for a thermostat recited in claim 7, further comprising: a heater protective portion covering a circumferential surface of the heater with the resin material and integrally formed with the connector portion.

9. The heater member for a thermostat recited in claim 7, wherein the lead wire and the terminal pin are joined to be electrically connected.

10. The heater member for a thermostat recited in claim 8, wherein the lead wire and the terminal pin are joined to be electrically connected.

11. The heater member for a thermostat recited in claim 9, wherein the lead wire and the terminal pin are connected by crimping.

12. The heater member for a thermostat recited in claim 10, wherein the lead wire and the terminal pin are connected by crimping.

13. A method for manufacturing the heater member for the thermostat device, comprising: a step of connecting the lead wire drawn from the bar-like heater disposed in the piston to the terminal pin, a step of insert-molding a connector section such that the terminal pin connected via the lead wire and the rear end face of the heater are arranged therein, wherein in the step of insert molding, the rear end face of the heater is disposed in an opening-formed portion, using a mold for forming an opening and an internal space communicating therewith in the connector portion.

14. The method for manufacturing the heater member for thermostats recited in claim 13, wherein in the step of insert molding, the heater protective portion covers the circumferential surface of the heater with the resin material and is integrally formed with the connector portion.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0029] FIG. 1 is a cross-sectional view of a thermostat device on which a heater member for a thermostat (a first Embodiments) according to the present invention is mounted;

[0030] FIG. 2 is a perspective view of a heater member 1;

[0031] FIG. 3(a) is a front view of the heater member, and FIG. 3(b) is a side view (partially a cross-sectional view) of the heater member;

[0032] FIG. 4(a) and FIG. 4(b) are side-views that illustrate the configuration of the connection of the terminal pin 8 and the terminal portion 5a of the heater 5;

[0033] FIG. 5 is a cross-sectional view of the thermostat device on which the heater member for a thermostat (a second Embodiment) according to the present invention is mounted;

[0034] FIG. 6(a) is a front view of the heater member 1, and FIG. 6(b) is a side view (partially a cross-sectional view) of the heater member 1; and

[0035] FIG. 7 is a cross-sectional view of a conventional heater member.

DESCRIPTION OF EMBODIMENTS

First Embodiment

[0036] A first embodiment of a heater member for a thermostat according to the present invention will be described based on the drawings below. FIG. 1 is a cross-sectional view of a thermostat device equipped with the heater member for a thermostat of the present invention.

[0037] An electrically-controlled thermostat device 10 shown in FIG. 1, installed in an engine cooling system, for example, is equipped at a crossing portion of a coolant passage from a radiator and a coolant passage from an outlet of the engine, and the temperature of the coolant toward an inlet of the engine is controlled by selectively switching the flow of the coolant in the first and second fluid passages composed of above coolant passages.

[0038] The thermostat device 10 is provided with a piston 18 having a bottomed cylindrical shape mounted hanging in a device housing 11 and a thermoelement 17 that is fittingly provided freely slidable along the axial direction in the outside thereof. At the upper-level portion in the axial direction of the thermoelement 17, a main valve body 15 is provided that opens and closes the fluid passage formed in the device housing 11.

[0039] In the thermoelement 17, a thermal expansion member such as wax is filled, and the tip end of the piston 18 is placed in the thermal expansion member; the temperature of the thermal expansion member is configured to be controllable by the heater 5 provided in the piston 18.

[0040] In the electrically-controlled thermostat device 10, a spring 16 urging the main valve body 15 and a spring seat 16a are provided, and also a second valve body that is to be a bypass valve and a bypass spring are provided. However, the structure thereof is well-known and specific drawings and descriptions will be omitted here.

[0041] In the drawings, reference sign 12 denotes the inlet of coolant from the radiator, reference sign 13 denotes the inlet from the bypass passage, reference sign 13a denotes an inlet to the downstream of the main valve body 15 from the inlet of the bypass passage, and reference sign 14 denotes an opening for the passage leading to the inlet of the engine. Further, reference sign 6 denotes a connector portion provided in the piston 18 which connects the heater 5 to the outside.

[0042] The heater member according to the present invention is a member including the heater 5 and the connector portion 6 and is denoted by reference sign 1 below.

[0043] 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 a cross-sectional view) of the heater member 1.

[0044] The heater member 1 is provided with the flat bar-like heater 5 made of ceramics and the resin-mold connector portion 6.

[0045] As shown in FIG. 3(b), in the connector portion 6, a pair of terminal pins 8 are placed fixedly. The terminal pins 8 are electrically connected to the terminal portions 5a of the heater 5 through the lead wires 9.

[0046] FIG. 4(a) and FIG. 4(b) are side-views that illustrate the configuration of the connection of the terminal pin 8 and the terminal portion 5a of the heater 5.

[0047] As shown in FIG. 4(a), a crimping portion 3 is provided at the rear end portion of the terminal pin 8, and the end portion of the lead wire 9 drawn from the terminal portion 5a is placed. Further, the end portions of the lead wire 9 are crimped at the crimping portion 3, as shown in FIG. 4(b), and the lead wire 9 is electrically connected to the terminal pin 8.

[0048] A rear end face 5b of the heater 5 is located in the connector portion 6, but the rear end face 5b is placed in the hollow 6c in the connector portion 6 so that the rear end face 5b does not come into contact with the resin material forming the connector portion 6. As shown in the perspective view of FIG. 2, an opening 6b, communicating with the hollow portion 6c in the connector portion 6, is formed at an approximately central area of a flange 6a, from which the heater 5 is extending out, and has a diameter size not to be in contact with the heater 5. Namely, the rear end face 5b of the heater 5 is disposed in the hollow portion 6c in the connector portion 6 without being in contact with the resin material.

[0049] This structure allows preventing the rear end face 5b of heater 5 from coming into contact with the molding the resin material when insert-molding of the connector portion 6 and heater 5 from damaging due to the molding pressure.

[0050] To manufacture such a heater member 1, first, terminal pins 8 and the lead wires 9 drawn out from the heater 5 are connected by crimping, as shown in FIGS. 4(a) and 4(b).

[0051] Then, to form the connector portion with the resin material, the heater 5 and the terminal pins 8, which are connected via the lead wires 9, are placed in a mold not shown in the drawing and molded by insert-molding. At this time, since the mold is formed such that the opening 6b and the hollow portion 6c communicating therewith in the connector portion 6 are formed, and the rear end face 5b of the heater 5 is placed at the place where the opening 6b is to be formed, the rear end face 5b of the heater 5 does not come into contact with the resin material and effects of molding pressure of the forming resin material to the heater 5 are avoided.

[0052] With thus configured heater member 1 for a thermostat, since, when insert-molding of the heater 5 and the connector portion 6, the rear end face 5b of the heater 5 is disposed in a hollow portion 6c and is not in contact with the resin material, the heater 5 is protected from molding pressure of the resin material (injection pressure, pressure by the mold) and prevented from damage occurring.

[0053] Further, the length of the lead wire 9 can be shortened, which allows for reducing the overall length of the heater member 1 and for contributing to the downsizing of products. Further, the terminal pins 8, lead wires 9, connector portion 6, and heater 5 can be insert-molded, allowing the manufacturing time to be shortened and the cost to be reduced. Further, the variation in molding dimension is reduced, thereby improving yields. Further, the lead wires 9 are disposed in the connector portion 6, thereby preventing the lead wires 9 from twisting.

[0054] Further, when the lead wires are connected to the terminal pins by crimping, this reduces the equipment costs compared to the laser bonding case and also avoids the problem of spattering burrs generated during laser bonding.

[0055] In the above Embodiment, the terminal pins 8 and the lead wires 9 are joined by crimping. The present invention is not limited by the Embodiment, and the junction of the terminal pins 8 and the lead wires 9 may be carried out by laser bonding or soldering.

Second Embodiment

[0056] A second embodiment of a heater member for thermostats according to the present invention will be described based on the drawings below.

[0057] FIG. 5 is a cross-sectional view of a thermostat device equipped with the heater member (a second Embodiment) for thermostats of the present invention. FIG. 6(a) is a front view of the heater member 1, and FIG. 6(b) is a side view (partially a cross-sectional view) of the heater member 1. It is noted that the same members as those in the first embodiment above are denoted with the same referential signs and the detailed description will be omitted.

[0058] In the second embodiment, as shown in FIGS. 5 and 6(a), (b), the heater protective portion 7 is provided to cover the circumferential surface of the heater 5 from the middle of the long heater 5 to the rear end side (connector portion 6 side), which is different from the first embodiment described above.

[0059] The heater protective portion 7 is integrally formed with the connector portion 6. That is, the heater protective portion 7 is formed with a resin material to cover the circumferential surface of heater 5 in insert-molding of the connector portion 6. Since the impact due to injection pressure is received by the mold during the formation of the heater protective portion 7, the pressure is not directly applied to the heater 5 and is weakened. Further, since the holding pressure is applied from the radial direction (in the lateral direction) and received by both sides of the flat surfaces, it is canceled and weakened.

[0060] Thus, in the second embodiment of the present invention, since the circumferential surface of the heater 5 is covered with the heater protective portion 7, the heat retention performance can be improved.

Referential Signs List

[0061] 1 heater member for thermostats [0062] 5 heater [0063] 6 connector portion [0064] 6b opening [0065] 6c hollow portion [0066] 7 heater protective portion [0067] 8 terminal pins [0068] 9 lead wires