JPH0961211A - Temperature sensing resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature sensing resistor that the mechanical strength of a mounting part is improved without lowering the thermal response of the resistor. SOLUTION: A reinforcing coat 11 of glass or resin is formed at the mounting part 1a of a temperature sensing resistor (insulating board 1). Since the coat 11 is formed, the effective thickness of the part 1a concentrated at the most mechanical stress at the time of mounting is increased, and the mechanical strength of the part 1a is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature sensitive resistor used in a flow velocity sensor or the like.

[0002]

2. Description of the Related Art As a sensor element of a flow rate sensor for measuring the flow rate (flow velocity) of a fluid such as air, a temperature sensitive resistor as shown in FIG. 3 or 4 is used. FIG. 3 shows a temperature-sensitive resistor in which a resistance film is not formed on the attachment portion, and FIG. 4 shows a resistance film formed on the attachment portion.

In this type of temperature-sensitive resistor, a resistance pattern 4 made of a resistance film 2 made of platinum or the like is formed on a rectangular insulating substrate 1 made of alumina or the like, and one end side in the longitudinal direction of the insulating substrate 1 is formed. Therefore, the extraction electrodes 5a and 5b are formed in a state of being electrically connected to both ends of the resistance pattern 4 on the circuit, and the lead wire 6 is connected to the extraction electrodes 5a and 5b by means such as welding. . The resistance pattern 4 is formed by forming the groove 3 in the resistance film 2 with a laser trimmer or the like.

A protective coat 7 made of glass, resin or the like is formed on the resistance film 2 to protect the resistance film 2 from moisture, dust, dust and the like and to mechanically reinforce the resistance film 2. There is. The protective coat 7 is formed by applying it by printing, spraying, a spinner or the like and then firing it. Further, the connecting portion of the lead wire 6 is covered with a reinforcing material 8 such as glass or resin, whereby the lead wire 6 is reinforced.

The temperature sensitive resistor is used as a heating resistor of a known resistance bridge circuit of a flow sensor, and in the use state (when mounted), the extraction electrodes 5a, 5 of the insulating substrate 1 are used.
A cylindrical support member 2 indicated by a broken line with the side b as the mounting portion 1a
It is attached to 0 and is arranged in a flow path such as air.

As described above, in particular, the temperature sensitive resistor used as a heat generating element needs to have its heat capacity as small as possible in order to improve the thermal response characteristics, and the insulating substrate 1 is as thin as possible (currently 150 μm) is required.

[0007]

As described above, this type of temperature-sensitive resistor uses an elongated and thin rectangular insulating substrate, and is attached to a supporting member with its longitudinal end portion as a mounting portion. Therefore, when an external force is applied to the temperature-sensitive resistor, mechanical external stress concentrates near the support part of the mounting part, especially when a large external force is applied to the tip of the temperature-sensitive resistor, There has been a problem that cracks such as cracks occur in a portion of the mounting portion where stress is concentrated.

In particular, the temperature-sensitive resistor shown in FIG. 3 has a problem that the resistor and the protective coat are not formed on the mounting portion, and the mounting portion has lower mechanical strength than other portions.
Further, also in the temperature sensitive resistor shown in FIG. 4, it is required to further improve the mechanical strength of the mounting portion.

Therefore, an object of the present invention is to provide a temperature-sensitive resistor having an improved mechanical strength of the mounting portion without lowering the thermal response of the temperature-sensitive resistor.

[0010]

To achieve the above object, the present invention comprises an insulating substrate, a resistance pattern and a lead electrode formed on the insulating substrate, and a predetermined portion of the insulating substrate is attached to a mounting portion. In the temperature-sensitive resistor of the present invention, a reinforcing coat for increasing the mechanical strength of the mounting portion is formed on the mounting portion.

According to the above construction, the reinforcing coat is newly formed on the mounting portion of the temperature sensitive resistor, and the effective thickness of the portion where the mechanical stress is most concentrated when mounted on the support member is set. Since the number is increased, the mechanical strength of the mounting portion can be improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof. In the temperature sensitive resistor of each of the following examples, the insulating substrate is about 150 μm, the resistive film is 1 to 2 μm,
The protective coat is formed with a thickness of 5 to 30 μm. In the figure, the same or corresponding parts and those having the same functions as those in the conventional example are designated by the same reference numerals. Further, in the following figures, the chain double-dashed line is a line showing the holding surface of the supporting member at the time of mounting.

FIG. 1 shows the structure of the temperature sensitive resistor according to the first embodiment of the present invention. FIG. 1 corresponds to FIG. 3 of the conventional example, in which (a) is a plan view and (b) is a sectional view.

As shown in FIGS. 1 (a) and 1 (b),
In the temperature-sensitive resistor of this embodiment, the reinforcing coat 11 is formed on the mounting portion 1a where the resistance film 2 is not formed. That is, the protective coat 7 used to protect the resistive film 2 shown in FIG. 3 of the conventional example is extended to the mounting portion 1a to form the reinforcing coat 11, and the protective coat 7 and the reinforcing coat are formed. 11 is formed simultaneously by screen printing.

The reinforcing coat 11 is made of glass, resin or the like, and is for increasing the effective thickness of the mounting portion 1a where the mechanical stress is most concentrated at the time of mounting to improve the mechanical strength of the mounting portion 1a. . The configuration other than the reinforcing coat 11 is the same as that of the conventional example shown in FIG. 3, and the description thereof is omitted.

In this structure, the reinforcing coat 1 is newly provided only on the mounting portion 1a to which the most mechanical stress is applied during mounting.
Since 1 is formed, the mechanical strength of the supporting portion of the mounting portion 1a and the vicinity of the supporting portion can be increased as compared with the conventional example without deteriorating the thermal response of the temperature sensitive resistor.

Although the protective coat 7 and the reinforcing coat 11 are made of the same material in this embodiment, the reinforcing coat 1
1 may be formed of glass or resin of a material having a mechanical strength higher than that of the protective coat 7. Further, the reinforcing coat 11 may be formed thicker than the protective coat. In such a case, after forming the protective coat 7, the reinforcing coat 11 is formed.

Next, FIG. 2 shows the structure of the temperature sensitive resistor according to the second embodiment of the present invention. FIG. 2 corresponds to FIG. 4 of the conventional example, where (a) is a plan view and (b) is a sectional view.

As shown in FIGS. 2 (a) and 2 (b),
In the temperature sensitive resistor of this embodiment, the reinforcing coat 11 is formed on the protective coat 7 of the mounting portion 1a of the insulating substrate 1.
That is, on the protective coat 7 used to protect the resistance film 2 shown in FIG. 4 of the conventional example, only the mounting portion 1a is
A reinforcing coat 11 having the same thickness and the same material as the protective coat 7 is formed. That is, the mounting portion 1a of the insulating substrate 1 is formed by laminating the protective coat 7 having a thickness of 5 to 30 μm and the reinforcing coat 11 having a thickness of about 15 μm. The configuration other than the reinforcing coat 11 is the same as that of the conventional example shown in FIG. 4, and the description thereof is omitted.

In this structure, since the reinforcing coat 11 is newly formed only on the protective coat 7 of the mounting portion 1a to which the most mechanical stress is applied at the time of mounting, the thermal response of the temperature sensitive resistor is deteriorated. Without this, the mechanical strength of the supporting portion of the mounting portion 1a and the vicinity of the supporting portion can be increased as compared with the conventional example.

Also in this embodiment, the reinforcing coat 11 may be formed of glass, resin, or the like, which is a material having a mechanical strength higher than that of the protective coat 7. Further, the thickness of the reinforcing coat 11 is appropriately set according to the desired mechanical strength.

In each of the above embodiments, the extraction electrodes 5a,
Although the description has been given of the case where 5b is formed on one end side in the longitudinal direction of the insulating substrate 1, the present invention is not limited to this, and the extraction electrode 5
The present invention can also be applied to a temperature sensitive resistor in which a and 5b are formed so as to face both ends, and both ends are attached. In this case, a reinforcing coat is formed on a predetermined portion of both mounting portions.

[0023]

As described above, according to the temperature sensitive resistor of the present invention, the reinforcing coat is newly formed on the mounting portion of the temperature sensitive resistor, and the portion where the mechanical stress is most concentrated at the time of mounting. Since the effective thickness is increased, the mechanical strength of the supporting portion of the mounting portion and the vicinity of the supporting portion can be further improved. Therefore, the occurrence of damage such as cracks in the mounting portion when an external force is applied to the temperature sensitive resistor can be significantly reduced as compared with the conventional one.

[Brief description of drawings]

FIG. 1A is a plan view of a temperature sensitive resistor according to a first embodiment of the present invention, and FIG. 1B is a sectional view.

2A is a plan view of a temperature sensitive resistor according to a second embodiment of the present invention, and FIG. 2B is a sectional view thereof.

3A is a plan view of a conventional temperature-sensitive resistor, and FIG. 3B is a sectional view.

FIG. 4A is a plan view of another conventional temperature-sensitive resistor,
(B) is a sectional view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 1a Attachment part 2 Resistive film 3 Groove 4 Resistance pattern 5a, 5b Lead electrode 6 Lead wire 7 Protective coat 8 Reinforcing material 11 Reinforcing coat 20 Supporting member

Claims (1)

[Claims] 1. A temperature-sensitive resistor comprising an insulating substrate, a resistance pattern formed on the insulating substrate, and a lead electrode, wherein a predetermined portion of the insulating substrate serves as a mounting portion. A temperature-sensitive resistor, characterized in that a reinforcing coat is formed to increase its mechanical strength.