JPS6380501A - Winding resistor bobbin - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a bobbin for a small wire-wound resistor, and in particular,
The present invention relates to a bobbin for a wire-wound resistor suitable for a hot wire air flow meter used for measuring the intake air flow rate of an internal combustion engine.

[Conventional technology]

The detection element of a hot wire air flow meter is a resistance element made of platinum wire or the like that generates heat through electric current.
A so-called hot wire element is used, and one type of such hot wire element is a wire-wound resistor in which a resistance wire is wound around a ceramic bobbin or the like.

By the way, as a conventional example of a bobbin for such a wire-wound resistor, as shown in Fig. 3, a ceramic pipe 1 is used.
It is known that lead wires 3a and 3b are inserted from both ends and fixed with an adhesive 2 such as glass paste. In addition, in this FIG. 3, 4 represents the hollow part left inside the pipe 1.

The conventional assembly method is to apply glass paste adhesive 2 to the pipe 1 and insert the nine leads 3a, then apply the same glass paste adhesive 2, insert the lead 3b, bond it, and fix it by firing. It is something to do.

Therefore, in this conventional example, although it is possible to make the initial insertion length of lead 3a constant using a jig, the insertion length of lead 3b
It is extremely difficult to maintain a constant insertion length. If the insertion length is short, a short circuit will occur between the leads 3a and 3b, and if the insertion length is short, the fixing force of the glass paste 2 between the leads 3a, 3b and the pipe 1 will decrease, and the lead 3 will be disconnected from the pipe 1.
A problem occurs where a and 3b come off.

That is, in this conventional example, no consideration was given to setting the insertion length of the lead into the pipe.

On the other hand, as a conventional example of such a bobbin, there is
As disclosed in Japanese Patent No. 30911, there is also known a system in which two lead wires are each formed with a flange portion, thereby regulating the amount of insertion of the lead wire into the pipe. .

However, in this conventional example, no consideration was given to problems caused by forming a flange portion on the lead wire.

[Problem that the invention seeks to solve]

In such bobbins, a method is often used to bond the ceramic pipe and the lead wire using a low-melting glass called solder glass and fix it by heating and firing. In the former method, no consideration is given to how to determine the fixed length of the pipe and lead when bonded and fired, and this point largely depends on the skill of the worker. The bond length was not constant. Furthermore, even if the length of the bond between the pipe and the lead was set constant, the initial bond length could not be secured because the lead was moved by the glass during firing.

As a result, problems have occurred, such as the lead coming off from the pipe due to an insufficient adhesive fixing length between the pipe and the lead, and short circuits between the leads due to an excessive adhesive fixing length.

On the other hand, in the latter case, as described in the above publication, a flange must be formed at the insertion part of the lead member, but in this case, the lead wire generally has a wire diameter of 0.
．． No consideration was given to the fact that it was quite thin, about 15 mm, and it was difficult to form a flange. In addition, there was a problem that the insert had to be inserted in a certain direction, reducing workability.

An object of the present invention is to provide a bobbin for a wire-wound resistor that allows lead wires to be easily and accurately attached without forming a flange portion on the lead wires.

[Means for solving problems]

According to the present invention, the above object is achieved by mixing insulating granules into the adhesive for bonding and fixing the pipe and the lead member constituting the bobbin.

[For production]

When lead members are inserted from both ends of the pipe, the adhesive is pushed in by the tips of the two lead members, but at this time, if granules are mixed into the adhesive, the granules may Since it is sandwiched between the end faces of the lead members, it is possible to prevent the lead members from coming into direct contact with each other, and it is possible to define the insertion length of the lead members.

One [Embodiment] Hereinafter, a bobbin for a wire-wound resistor according to the present invention will be described in detail with reference to an illustrated embodiment.

FIG. 1 shows an embodiment of the present invention, and FIG. 2 is an enlarged view of part A thereof. This embodiment is basically the same as the conventional example shown in FIG. 3, but in this embodiment, The difference is that granules 5 made of an insulating material are mixed into the glass paste adhesive 2.

As the leads 3a, 3b are inserted into the pipe 1, the granules 5 are mixed with the adhesive 2.
It is pushed in by the tips of leads 3a and 3b, and is eventually caught between the tips of leads 3a and 3b.

As a result, as is clear from FIG. 2, the ends of the leads 3a and 3b are separated by a predetermined dimension by the granular material 5, and there is no short-circuit, and the leads 3a and 3b are separated by a predetermined dimension. This allows accurate positioning while maintaining the insertion length up to the limit.

The granules 5 at this time may be any material as long as it can withstand baking bonding using glass paste and is insulating, but as an example, white arundum was used and good results were obtained. Ta.

In addition, the particle size of the 50 granules at this time is 8 to 80 μm.
M was used, and it had excellent workability and was fully satisfactory.

〔Effect of the invention〕

As explained above, according to the present invention, the possibility of a short circuit occurring between the leads is prevented by the granules, so the insertion length of the leads into the bobbin pipe can be maximized. It is possible to obtain sufficient adhesion strength of the lead to the pipe, and since the lead does not require processing such as a flange, the cost can be reduced and workability can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a bobbin of a wire-wound resistor according to the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a sectional view showing a conventional example. 1...Pipe, 2...Adhesive, 3a,
3b...Lead, 4...Hollow part, 5.
...Granular material. Figure 1 Figure 3] 2

Claims (1)

[Scope of Claims] 1. In a bobbin for a wire-wound resistor in which conductive leads are inserted and fixed from both ends of a pipe made of an insulating material, the conductive leads are made of an adhesive mixed with insulating granules. A bobbin for a wire-wound resistor, characterized in that the bobbin is fixed to the pipe. 2. The bobbin for a wire-wound resistor according to claim 1, wherein the material of the pipe is ceramics, and the adhesive is low-melting glass. 3. A bobbin for a wire-wound resistor according to claim 1 or 2, characterized in that the grain size of the granules is within 8 to 80 μm.