JPH09170954A - Temperature detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature detector wherein two temperature sensing elements having different detection output level respectively are incorporated properly and at least one element can be grounded easily. SOLUTION: A thermistor 11 is arranged as a first low-output temperature sensing element on the bottom of a metallic case 32 and a thermistor 21 is arranged as a second high-output temperature sensing element, a specified distance apart from the first element, within the case 32. The thermistor 11 is connected with terminals 14 and 15 through lead wires 12 and 13, and the thermistor 21 is connected with terminals 24 and 25 through lead wires 22 and 23. While the terminal 25 is joined with a flange 32f on the opening end of the case 32, the case 32 is filled with a synthetic resin, and they are all formed integrally into a specified shape, resulting in a temperature detector 1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a temperature detector,
In particular, the present invention relates to a temperature detector capable of having both functions of a water temperature sensor and a water temperature gauge for automobiles.

[0002]

2. Description of the Related Art Conventionally, as a temperature detector for detecting a cooling water temperature for an automobile, a so-called water temperature sensor for supplying a highly accurate low output signal to an electronic control unit for engine control and an instrument panel are provided. There are two types of so-called water temperature gauges that provide a high output signal to a water temperature gauge. The former is constructed as shown in FIG. 3, for example, and the latter is constructed as shown in FIG. 4, for example.
JP-A-4-319634, and an example of the latter is disclosed in Japanese Unexamined Patent Publication No.
No. 268425.

In the water temperature sensor shown in FIG. 3, a holder 52 of a synthetic resin bottomed cylinder is housed in a housing 51 made of metal and having a bottomed cylinder, and a thermistor 53 is arranged at the bottom of the holder 52. Has been done. The thermistor 53 is connected to a terminal 55 via a lead wire 54, and the terminal 52 is extended to the outside of the holder 52 and the holder 52 is
A connector 56 is formed integrally with the housing 51 by resin molding including the inside. Thus, the cylindrical portion accommodating the thermistor 53 is arranged so as to be located in the cooling water channel to be measured. In addition, in Japanese Patent Laid-Open No. 4-319634, in order to ensure stable electrical connection even when a mechanical load is applied to the lead wire due to a difference in coefficient of thermal expansion between materials during a thermal cycle, the lead wire and the terminal are The connecting part is composed of a welding part and a soldering part.

On the other hand, in the water temperature gauge shown in FIG. 4, an insulator cylindrical insulator 62 is housed in a housing 61 made of metal and having a bottomed cylindrical body, and a thermistor 63 is housed in the insulator 62. , Housing 6
It is located at the bottom of 1. A conductor coil spring 65 is housed in the insulator 62 so as to be pressed against the thermistor 63 via the conductor disk 64. Further, the terminal 66 is arranged so as to come into contact with the end of the coil spring 65, is joined to the opening of the housing 61 via the packing 67, and the holder 68 of the insulating molded body is further mounted to fix the coil spring 65. In the pressed state, they are caulked and coupled by the opening end edge of the housing 61. Thus, the cylindrical portion accommodating the thermistor 63 is arranged so as to be located in the cooling water channel to be measured. Incidentally, JP-A-4-26842
In No. 5, an adhesive is applied to the joint between the metal case and the insulating molded body for the purpose of preventing the reduction of the torque strength around the insulating molded body incorporated in the opening of the metal case.

[0005]

The objects to be measured by the water temperature sensor and the water temperature gauge are the same cooling water, but different output levels are required depending on the equipment on the output side. Temperature detectors are needed. Therefore, not only the cost of the detector is two, but also the cost is high because there are two mounting portions and two mounting operations. For this, cost reduction can be considered by integration, but when the water temperature sensor of FIG. 3 and the water temperature gauge of FIG. 4 are integrated, the arrangement of the water temperature sensor and the water temperature gauge, the attachment to the attachment portion, the structure In view of simplification, the water temperature sensor is required to be connected to a pair of terminals, and the water temperature gauge is required to be connected to one terminal and grounded to the mounting portion.

However, when the temperature detector constructed as described above is mounted, if the mounting portion is not a conductor, it is necessary to connect it to a predetermined portion via a ground wire. Especially in recent vehicle engines, water housings made of synthetic resin are becoming widespread, and if a temperature detector is attached to this water housing,
Ground connection becomes difficult. That is, when the water temperature gauge also has a pair of terminals like the water temperature sensor, the connection destination of the ground side terminal becomes a problem.

Therefore, the present invention provides a temperature detector in which two temperature-sensitive elements having different detection output levels are appropriately incorporated and at least one of the temperature-sensitive elements can be easily grounded. To aim.

[0008]

In order to achieve the above-mentioned object, a temperature detector of the present invention comprises a metal case having a cylindrical shape with a bottom and a first low power output arranged at the bottom of the metal case. A temperature-sensitive element and a high-output second temperature-sensitive element which is arranged in the metal case at a predetermined distance from the first temperature-sensitive element;
A pair of first terminals connected to the first temperature-sensitive element via lead wires; and a pair of second terminals connected to the second temperature-sensitive element via lead wires; While one of the second terminals is joined to the open end of the metal case, the metal case is filled with a synthetic resin, and a part of the first and second terminals is provided.
The first and second temperature sensitive elements and the lead wire are included and integrally molded into a predetermined shape.

In the temperature detector, the second temperature sensitive element is arranged on the same axis as the first temperature sensitive element with a predetermined distance in the mounting base direction, and the first and the second temperature sensitive elements are arranged. The second temperature sensitive element may be disposed in the fluid to be measured, and the axis on which the first and second temperature sensitive elements are disposed may be arranged substantially orthogonal to the flow direction of the fluid to be measured. desirable.

Thus, in the temperature detector constructed as described above, currents are supplied to the first and second temperature sensitive elements via the appropriately connected first and second terminals, respectively. For example, the temperature of the fluid is detected based on the resistance value that changes according to the temperature of the fluid to be measured. At this time, since the first temperature sensitive element, which requires high accuracy, is arranged at the bottom of the temperature detector, the temperature of the fluid can be appropriately detected, and the temperature of the fluid at a portion separated from the mounting base and having a high flow velocity can be detected. Therefore, high accuracy can be maintained without being affected by heat generation of the high-output second temperature sensitive element portion.

[0011]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 relate to one embodiment of the present invention, and FIG. 1 shows a state in which a temperature detector 1 of this embodiment is mounted on a water housing 2 of an internal combustion engine. The temperature detector 1 of the present embodiment is the first referred to in the present invention.
And thermistors 11 and 21 which are second temperature sensitive elements,
Together with these, the lead wires 12 and 13 and the terminals 14 and 15 constituting the pair of first terminals of the present invention, and the lead wires 22 and 23 and the terminals 24 and 25 constituting the pair of second terminals of the present invention are integrated. Has been formed. The thermistor 11 functions as a water temperature sensor and has a low output, whereas the thermistor 21 functions as a water temperature gauge and has a high output, and is larger than the thermistor 11. Hereinafter, the structure of the temperature detector 1 will be described generally along the manufacturing process.

First, the pair of lead wires 12 and 13 connected to the thermistor 11 are connected to the pair of terminals 14 and 15 by welding or soldering, respectively. Similarly, a pair of lead wires 22 connected to the thermistor 21,
23 is connected to the pair of terminals 24 and 25 by welding or soldering, respectively. These terminal 1
4, 15, 24, and 25 are held by a synthetic resin holder 31 to form a sub-assembly. This sub-assembly is housed in a metal case 32 having a bottomed cylindrical shape, the thermistor 11 is arranged at the bottom, and the same direction as the opening direction of the metal case 32 (the mounting base 33 described later).
The thermistor 21 is arranged at a position separated by a predetermined distance in the (direction).

The metal case 32 is formed in a cylindrical shape having a small diameter so that the thermistor 11 and the thermistor 21 can be fitted in close contact with each other, and a portion thereof separated from the metal case 32 by a predetermined distance is expanded to form a thermistor. 21 is formed in a large-diameter cylindrical shape. Thus, the thermistor 21 has a disk shape, but as shown in FIG. 1, its outer peripheral surface is in contact with the inner surface of the metal case 32, and
The connecting portion between the large-diameter cylindrical portion and the small-diameter cylindrical portion of the lead wire 12 for the thermistor 11 is provided through the gap between the flat surface portion of the thermistor 21 and the inner surface of the metal case 32 as shown in FIG.
It is formed in a tapered shape so that (13) can be inserted. The open end of the metal case 32 is bent outward and expanded to form a flange portion 32f, as shown in FIGS.

After the sub-assembly including the thermistors 11 and 12 is housed in the metal case 32, the ground side terminal 25 connected to the thermistor 21 is changed to the one shown in FIG.
As shown in FIG. 5, it is joined to the flange portion 32f of the metal case 32 by welding or soldering. And the metal case 32
The inside is filled with a synthetic resin, and as shown in FIGS. 1 and 2, the mounting base portion 33, the connector portion 34, and the flange portion 3 are provided.
5 is integrally formed. That is, the mounting base portion 33 including the flange portion 32f of the metal case 32 is formed by resin molding, the flange portions 35 are extended and formed on both sides thereof, and the connector portion 34 is integrally formed with these.
As shown in FIGS. 1 and 2, the connector portion 34 is formed in a container shape surrounding the terminals 14, 15 and 24 with the tip portions thereof exposed. The flange portion 35 has mounting holes 35a formed on both sides thereof as shown in FIG.

On the other hand, as shown in FIG. 1, a ground member 40 of a conductor having a spring property is joined to the inner surface of the water housing 2, and a hole corresponding to the mounting hole 2a is formed at one end thereof. The peripheral portion is cut and raised to form an engaging portion 41. Also, the ground member 4
A contact portion 42 is formed on the other end side of 0 and is pressed against the metal cylinder head 4 by its elastic force.

The temperature detector 1 constructed as described above is
As shown in FIG. 1, a synthetic resin water housing 2
The metal case 32 is disposed so that its tip portion projects into the cooling water passage through a mounting hole 2a that is formed substantially vertically to the outer surface of the water housing 2 around the mounting hole 2a. The engaged locking portion 2b (shown in a state after being bent in FIG. 1) is inserted into the mounting hole 35a of the flange portion 35. Then, the tip of the engaging portion 2b is heated and pressed to bend as shown in FIG. 1, and the flange portion 35 is caulked and fixed to the water housing 2. Thus, the metal case 32 is arranged so as to be substantially orthogonal to the flow direction of the cooling water,
The thermistor 11 is located on the center side of the cooling water channel (the side separated from the mounting base 33), and the thermistor 21 is located on the peripheral side (the side close to the mounting base 33). The O-ring 3 is provided on the outer peripheral edge of the mounting hole 2a of the water housing 2.
Are arranged.

At this time, the metal case 32 is attached to the ground member 4
It engages with the engaging portion 41 of 0, is electrically connected to the cylinder head 4 through the contact portion 42, and is surely grounded. Then, a wiring connector (not shown) is connected to the connector portion 34, the terminals 14 and 15 are connected to, for example, an electronic control device (not shown) for a fuel injection control device (not shown), and 24 is connected to a water temperature gauge (not shown) of an instrument panel (not shown).

Thus, the thermistor 11 and the thermistor 2
1, electric current is supplied via the terminal 14 (or 15) and the lead wire 12 (or 13), and the terminal 24 and the lead wire 22, respectively, and changes according to the temperature of the cooling water in the water housing 2. The temperature of the cooling water is measured based on the resistance value. At this time, the thermistor 11, which requires high accuracy, can detect the temperature of the cooling water in the water housing 2 through the side surface and the bottom surface of the metal case 32, and further, the cooling water in the portion where the flow velocity is high on the center side of the cooling water passage. High temperature thermistor 2 because it can detect temperature
High accuracy can be maintained without being affected by heat generation in one portion. Although the fluid to be measured is cooling water in the present embodiment, other fluid such as oil may be used, and the fluid is not limited to the water housing 2 and may be applied to other fluid passages.

[0019]

Since the present invention is configured as described above, the following effects can be obtained. That is, the temperature detector of the present invention includes the first and second temperature detectors in a bottomed cylindrical metal case.
The synthetic resin is filled in the metal case with one of the pair of second terminals, which accommodates the temperature sensitive element and is connected to the second temperature sensitive element via a lead wire, is joined to the open end of the metal case. In addition, the first and second temperature sensitive elements are included and integrally molded into a predetermined shape.
The temperature-sensitive element can be easily grounded via the metal case. Moreover, since the temperature of the fluid to be measured can be properly detected without the mutual influence of the first and second temperature sensitive elements, stable detection accuracy can be ensured for each.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a temperature detector according to an embodiment of the present invention.

FIG. 2 is a side sectional view of a temperature detector according to an embodiment of the present invention.

FIG. 3 is a sectional view of a conventional water temperature sensor.

FIG. 4 is a cross-sectional view of a conventional water temperature gauge.

[Explanation of symbols]

 1 Temperature Detector 2 Water Housing 3 O-ring 4 Cylinder Head 11 Thermistor (First Temperature Sensitive Element) 12, 13 Lead Wire 14, 15 Terminal (First Terminal) 21 Thermistor (Second Temperature Sensitive Element) 22, 23 Lead Wires 24, 25 Terminals (Second Terminal) 31 Holder 32 Metal Case 33 Mounting Base 34 Connector Part 35 Flange Part 40 Grounding Member

Claims (1)

[Claims] 1. A bottomed cylindrical metal case, a low-power first temperature-sensitive element arranged at the bottom of the metal case, and a predetermined distance from the first temperature-sensitive element. A high-power second temperature-sensitive element arranged in a metal case, a pair of first terminals connected to the first temperature-sensitive element via lead wires, and a lead wire for the second temperature-sensitive element. And a pair of second terminals connected to each other via a pair of second terminals, wherein one of the pair of second terminals is joined to an open end of the metal case, and the metal case is filled with a synthetic resin. A temperature detector comprising a part of the first and second terminals, the first and second temperature sensitive elements, and the lead wire and integrally molded into a predetermined shape.