JPS6229733B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for manufacturing a resistance temperature detector that measures temperature by a change in electrical resistance.

As for the conventional manufacturing method of this kind, the patent application
There is 001916. As shown in Fig. 1, this manufacturing method involves inserting an insulating tube 1 made of an inorganic insulator into a cylindrical shape, dried, and provided with through holes 2, 2 for the conductor, into a metal inner tube 3 that is open at both ends. The metal inner tube 3 is then processed to reduce its diameter, and the insulating tube 1 inside the metal inner tube 3 is crushed, formed into inorganic insulating powder, and the conductive wires 4, 4 inserted into the through holes 2, 2 of the insulating tube 1 are crushed. The inorganic insulating powder is inserted into the metal inner tube 3, and the ends of the metal inner tube 3 are partially cut off to form conductive wires 4, 4.
are exposed, the lead wires 6, 6 of the resistive element 5 are connected and fixed to the conductive wires 4, 4, and the opening 8 is opened at one end.
A small amount of inorganic insulating powder 9 is put into the metal outer tube 8 through the opening 8a at the other end of the metal outer tube 8, which is formed by joining the lid body 7 to the metal outer tube 8 by welding or the like. The metal inner tube 3 is inserted into the metal outer tube 8, and the metal outer tube 8 is reduced to a required diameter to separate the metal inner tube 3 and the metal outer tube. A double tube structure is formed by promoting close contact with the tube 8, and the resistance element 5 in the metal outer tube 8 is housed inside the metal outer tube 8 via the small amount of inorganic insulating powder 9.

However, in the conventional manufacturing method, the inorganic insulating powder 9 is charged into the metal outer tube 8 from the opening 8a at the other end with one end of the metal outer tube 8 closed with the lid 7 in advance. Insulating powder 9 into opening 8
Since the metal outer tube 8 is moved from the opening 8a to the closed end opposite to the opening 8a, this operation takes time and is extremely inefficient. Since the metal inner tube 3 to which the resistance element 5 is connected and fixed is inserted, when the resistance element 5 is inserted into the closable end of the metal outer tube 8, the resistance element 5 is removed from the center of the metal outer tube 8. There is a risk that the inorganic insulating powder 9 may be unbalanced and accommodated in contact with the inner wall of the metal outer tube 8, and in this case, the inorganic insulating powder 9 will be packed unevenly around the resistor element 5, and the inorganic insulating powder 9 will be packed unevenly around the resistive element 5. has the function of protecting the resistance element 5 from vibrations and shocks and improving heat conduction from the metal outer tube 8 to the resistance element 5, but among these functions, the vibration and shock buffering function is will not be able to perform to its full potential. Moreover, since one end of the metal outer tube 8 is closed, it is not possible to confirm the housing condition of the resistance element 5 in the metal outer tube 8, and therefore, the resistance element is not sufficiently protected from vibration and impact. There was a drawback that there was a risk. In addition, in the conventional manufacturing method of a measuring resistor, the resistance element 5 is fixed to the metal inner tube 3 and then combined with the metal outer tube 8. , 4 is fixed to the metal inner tube 3 and is not necessarily in a stable state, so there are problems such as the resistance element 5 bending when inserted into the metal outer tube 8, and the connection The inorganic insulating powder 9 previously housed in the metal outer tube 8 is difficult to clog between the pair of lead wires 6, 6 and the conductive wires 4, 4, which leads to poor insulation and other reliability problems. .

The present invention is intended to solve the conventional drawbacks, and its purpose is to provide a structure that can be assembled in a short time, has extremely high productivity, and is excellent in resistance to vibration damping of the resistance element. It is possible,
Another object of the present invention is to provide a method for manufacturing a temperature measuring resistor in which a resistance element is held at a predetermined position within a metal tube, has excellent electrical insulation, and is highly reliable.

An embodiment of the present invention will be described below with reference to FIGS. 2 to 4.

In the figure, 11 is a conductor wire 1 made of inorganic insulator, molded and dried into a cylindrical shape, and having the required length and diameter.
3 and 13 (for example, nickel wire) are inserted into the insulating tube 11.
The metal inner tube 15 to be inserted is a metal outer tube, and the conductive wires 13 and 1 are inserted into the through holes 12 and 12 provided in the insulating tube 11.
3, the insulating tube 11 is inserted into the separately prepared metal inner tube 14, and the metal inner tube 14 is further reduced in diameter to a required outer diameter using a diameter reducing machine such as a swaging machine.

Through such diameter reduction processing, the metal inner tube 14
The insulating tube 11 inserted therein is crushed to form inorganic insulating powder, and the conductive wires 13, 13 are placed inside the metal inner tube 14 via the inorganic insulating powder.

Next, the metal inner tube 14, which has been extended by diameter reduction processing as described above, is cut to a required length, and a portion of the end thereof is cut off, and the conductive wires 13, 13 are cut to the cut length as shown in FIG. Only the conductor wires 13, 13 are exposed.
The lead wires 17, 17 of the resistance element 16 are connected and fixed to the resistor element 16 by fixing means such as silver solder welding. Furthermore, the outer periphery of these conductors 13, 13, including the exposed portions and the area between the pair of lead wires 17, 17 connected thereto, is coated to increase strength and ensure insulation between the pair of lead wires and between the conductors. An insulating reinforcing portion 18 made of cement material is fixed to.

After doing this, the separately prepared metal inner tube 14
The resistance element 16 is placed inside the metal outer tube 15 which has an inner diameter slightly larger than the outer diameter of the metal outer tube 15 and has the same length as the length of the inner metal tube 14 plus the length of the resistance element 16 and is open at both ends. The connected metal inner tube 14 is inserted from the distal end of the resistance element 16 into one end opening 15a of the metal outer tube 15, and the resistance element 16 is housed near the other end opening 15b in the metal outer tube 15. This metal outer tube 15 is reduced in diameter to a required diameter using a diameter reducing machine.

Next, from the other end opening 15b of the metal outer tube 15, the resistance element 16 is accommodated from the end of the metal outer tube 14 in the metal outer tube 15 to the other end opening 15b of the metal outer tube 15. A small amount of inorganic insulating powder 19 is inserted into the metal outer tube 15 near the other end opening 15b. In this case, the opening 1 of the metal outer tube 15
It is confirmed that the resistance element 16 is located at the center of the metal outer tube 15 when viewed from 5b, and the inorganic insulating powder 19 is inserted around the resistance element 16 with a substantially uniform thickness. In this case, as described above, the insulation reinforcing portion 18 is already formed at the connection portion between the lead wires 17, 17 of the resistance element 16 and the conducting wires 13, 13, and the pair of leads, which is a portion where the inorganic insulation powder 19 is difficult to enter, is Since the space between the wires 17, 17 and the conducting wires 13, 13 is filled, filling the inorganic insulating powder 19 is easy and requires no effort, and the insulation reinforcing portion 1
Due to the reinforcing action of 8, the resistance element 16 will not be shifted to one side within the metal outer tube 15 when the inorganic insulating powder 19 is filled.

The inorganic insulating powder 19 interposed between the resistance element 16 and the metal outer tube protects the resistance element 16 from vibrations and shocks, and also protects the resistance element 16 from vibrations and impacts.
This is to improve heat conduction between 6 and 6.

Furthermore, the lid body 20 is joined by welding or the like to the end of the other end opening 15b of the metal outer tube 15 in which the metal inner tube 14 is fixed, the resistance element 16 is housed, and the inorganic insulating powder 19 is inserted. and close the lid.

In this way, the metal inner tube 14 and the metal outer tube 1
5 maintains close contact to form a double tube structure, and the resistance element 16 inserted into the metal outer tube 15 is also inserted into the metal outer tube 15 via a small amount of inorganic insulating powder 19.

As shown in the above-mentioned embodiments, the present invention involves inserting a metal inner tube to which a resistance element is connected into a metal outer tube with both ends open, and reducing the diameter of the metal outer tube to form a double tube structure. Inorganic insulating powder is inserted into the open end of the tube on the side where the resistance element is built in, and then the open end of the metal outer tube where the resistance element is built in is closed with a lid body. An inner metal tube, in which an inorganic insulating powder is introduced through the opening at the other end of a metal outer tube whose one end can be closed, and is moved to the closed end, and a resistance element is connected from the opening at the other end of the metal outer tube. Compared to manufacturing methods in which the metal outer tube is inserted into the metal outer tube and then the diameter of the metal outer tube is reduced to form a double tube structure, the inorganic insulating powder can be inserted without moving from one end of the metal outer tube to the other. Since it can be inserted directly into the parts, assembly time is greatly shortened and production efficiency is increased, and with the manufacturing method of the present invention, the number of products produced in the same amount of time is about 50% higher than conventional methods. Can be supplied in large quantities at low prices. In addition, since the resistance element is built into the opening of the metal outer tube, when inserting the inorganic insulating powder around the resistance element, adjust and check that the resistance element is placed in the center of the metal outer tube. Since the insulating powder can be inserted, the inorganic insulating powder is uniformly packed around the resistive element, which has the advantage of sufficiently protecting the resistive element from vibrations and shocks and stabilizing the quality. Furthermore, according to the method of the present invention, before filling the metal outer cylinder around the resistance element with the inorganic insulating powder, the exposed portions of the pair of conductive wires and the space between the pair of lead wires of the resistance element connected to the conductive wires are removed. Since the insulation reinforcement part is formed by fixing insulating material to the outer periphery of the resistance element, when filling inorganic insulation powder around the resistance element, it is difficult for this inorganic insulation powder to enter between the pair of lead wires. Since the area is occupied by the insulation reinforcement part and there is no need to fill this part with inorganic insulation powder, the filling operation can be carried out efficiently, and since it is easy to fill inorganic insulation powder, there is no need to create a void, making manufacturing easier. The resistance element can be held in a predetermined position without bending or wobbling, improving the reliability of electrical insulation.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway side view of a resistance temperature sensor for explaining the conventional manufacturing method, Figures 2 and 3 are
The figure is a partially cutaway side view of a resistance temperature sensor for explaining the manufacturing method of the present invention, and Figure 4 is A of Figure 3.
-A cross-sectional view. In the figure, 11... Insulating tube, 12, 12... Through hole of insulating tube, 13, 13... Conducting wire, 14... Metal inner tube, 15... Metal outer tube, 16... Resistance element, 1
7, 17...Resistance element lead wire, 19...Inorganic insulating powder, 20... Lid.

Claims (1)

[Claims] 1. Insert an insulating tube made of an inorganic insulating material into a cylindrical shape, dried, and provided with a through hole into which a pair of conductive wires are inserted, into a metal inner tube, and insert a pair of conductive wires into the through hole of the insulated tube. The diameter of the metal inner tube is reduced, the insulating tube inside the metal inner tube is crushed to form an inorganic insulating powder, and the conductive wire inserted into the through hole of the insulating tube is inserted into the metal through the inorganic insulating powder. The resistance element is fixed to the metal inner tube by placing it inside the tube, and further cutting off a part of the end of the metal inner tube to expose a pair of conductive wires, and connecting the pair of lead wires to the conductor wires. Further, an insulating material is fixed to the outer periphery of the pair of conductive wires including the exposed portions and between the pair of lead wires connected thereto to form an insulation reinforcing portion, and further the metal inner tube is fixed to one end thereof. Insert the metal outer tube into the metal outer tube through the opening, place a resistance element inside near the opening at the other end of the metal outer tube, reduce the metal outer tube to the required diameter, and bring the metal inner tube and metal outer tube into close contact. to form a double structure,
Inorganic insulating powder is inserted into the metal outer tube part containing the resistance element through the opening at the other end, and then a lid body is joined to the opening at the other end of the metal outer tube by welding or the like to close the lid. A method for manufacturing a resistance temperature sensor characterized by: