JP2873655B2 - Temperature sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature sensor for measuring a temperature by bringing a contact surface of a thermocouple into contact with a surface of an object to be measured, and more particularly to a temperature sensor whose contact surface has a desired pressing force. It relates to things that are pressed against objects.

[0002]

2. Description of the Related Art A conventional temperature sensor is disclosed, for example, in Japanese Utility Model Laid-Open Publication No. 3-83829. This consists of a thermocouple consisting of a contact surface pressed against an object to be measured and thermocouple wires extended from both ends of the contact surface, and an insulating tube in which the contact surface is located on the upper surface and the thermocouple wire is located on the side surface. A protective tube located outside the thermocouple wire, and a coil spring for urging the heat insulating tube upward to project the contact surface from the upper surface of the protective tube, and resisting the elastic force of the coil spring. By pressing the contact surface up to the upper surface of the protection tube, the contact surface can be pressed against the object to be measured with a desired pressing force.

[0003]

Since the above-mentioned structure requires a coil spring to obtain a desired pressing force, the number of parts increases, the structure becomes complicated, and the cost increases. was there.

[0004] Therefore, a technical problem of the present invention is to make it possible to press a contact surface of a thermocouple against an object to be measured with a desired pressing force without using a coil spring.

[0005]

Means for Solving the Problems The technical means of the present invention taken to solve the above technical problems is a contact surface pressed against an object to be measured and a thermoelectric element extended from both ends of the contact surface. A thermocouple composed of a pair of wires, a heat insulating tube in which the contact surface is located on the upper surface and the thermocouple wire is located on the side surface, and a protective tube located outside the thermocouple wire. A temperature sensor in which the contact surface is pushed down to
The thermocouple wire has an elastically deformed portion that is bent inward in advance, and a concave portion that allows the thermocouple wire to be deformed inwardly when the contact surface is pressed down. And a gap is formed between the contact surface of the thermocouple and the upper surface of the heat insulating tube.

[0006]

The operation of the above technical means is as follows.
When the contact surface of the thermocouple is pressed against the object to be measured, the thermocouple is displaced in the direction of the upper surface of the heat insulating tube, and the elastically deformed portion of the thermocouple wire that has been bent inward is bent further inward, and the contact surface is bent. Is pushed down to the upper surface of the protection tube 23. Therefore, the contact surface is pressed against the object to be measured with a desired pressing force by the elastic reaction force of the elastic deformation portion of the thermocouple wire.

[0007]

An embodiment showing a specific example of the present invention will be described (see FIG. 1). In this embodiment, a temperature sensor according to the present invention is combined with a vibration sensor.

A vibration transmitting plate 2 having a female thread is screw-coupled to a vibration detecting needle 1 having a small external thread formed on the lower portion, and the upper surface of the vibration transmitting plate 2 is in contact with the lower surface of the large diameter portion.
An upper electrode plate 3, a piezoelectric element 4, a lower electrode plate 5, and a weight 6 are sequentially inserted below the vibration transmission plate 2, are brought into contact with each other by a nut 7, and are fixed to the vibration detection needle 1. The vibration detecting needle 1 and the vibration transmitting plate 2 are formed of stainless steel, the upper and lower electrode plates 3 and 5 are formed of phosphor bronze, and the weight 6 is formed of zirconia ceramic. The vibration detecting needle 1, the vibration transmitting plate 2, the upper electrode plate 3, the piezoelectric element 4, the electrode plate 5, and the weight 6 form a vibration detecting unit of a vibration sensor.

The vibration detecting unit has an upper wall provided with a cut in the upper surface of the vibration transmitting plate 2 and a lower surface of the weight 6 on the side facing the front, and a fork extending downward further from the end on the side facing the upper wall. The upper part of the vibration transmission plate 2 is brought into contact with the lower surface of the upper wall of the switch fitting 9 by being sandwiched and held by the switch fitting 9 comprising the spring part of the switch fitting 9 and urged upward by the spring part of the switch fitting 9. ing. The switch fitting 9 has two side walls extending downward from the upper wall, and the side wall and the upper wall are held by the inner wall of the casing 10 so that the vibration detecting unit can be mounted on the casing. 1
0 is attached.

[0010] The casing 10 is formed of two casing members on the near side opposite to the paper surface, and the taper screw 1 is formed.
1, 12 are connected. The switch fitting 9 is made of stainless steel, and the casing 10 is made of PEEK. Conductors (not shown) from the upper and lower electrode plates 3 and 5 are connected to terminals 14 and 15 of the signal processing circuit 13.

The thermocouple wires 16a and 16b, which are composed of long thin plates of chromel and alumel, are bent inward at the upper ends thereof, and extend downward in the shape of a disk having holes in the center of the upper and lower portions of the bent portion. A contact plate 17 having two legs and a disk-shaped protection plate 18 having a hole in the center are fixed by welding. A thermocouple is formed from the thermocouple wires 16a and 16b, the contact plate 17 and the protection plate 18.

The hollow cylindrical heat insulating tube 19 located inside the thermocouple comprises an upper small-diameter portion, a lower large-diameter portion, and a long middle diameter portion therebetween, with the upper end and the lower end remaining in the middle diameter portion. Thus, two windows 20a and 20b having the same width as the diameter of the hollow portion and communicating with each other through the hollow portion are formed on both sides, and both windows 20a and 20b are formed.
The upper left portion of b is cut vertically, and the lower left portions of both windows 20a and 20b are cut inward upward.

In the thermocouple, the protection plate 18 has a slight gap 21 between the lower surface thereof and the upper surface of the heat insulating tube 19, and the thermocouple wires 16a and 16b are formed inside the window from outside the small diameter portion of the heat insulating tube 19 and into the window. It is wound into the large-diameter hole from the outside of the large-diameter portion through the lower surface, and is fixed by the ring 22 pressed into the large-diameter hole. The portions of the thermocouple wires 16a and 16b located in the windows are elastically deformed portions 23a and 23b which are bent inward in advance, respectively.
When the contact plate 17 is pressed down,
It can be elastically deformed further inward as long as it does not contact the inner vibration detection needle 1.

Outside the small diameter portion and the medium diameter portion of the heat insulating tube 19, a protective tube 2 having an inner diameter slightly larger than the outer diameter of the middle diameter portion.
4 has been inserted. The protection tube 24 is fitted to a projection 25 indicated by a dotted line formed at the lower end of the side surface of the middle diameter portion of the heat insulating tube 19 to prevent the protection tube 24 from being pulled out. The thermocouple, the heat insulating tube 19, the ring 22, and the protective tube 24 form a temperature measuring unit of a temperature sensor. Contact plate 17, protective plate 18, and protective tube 23
Is formed of stainless steel, the heat insulating tube is formed of PEEK, and the ring 22 is formed of bakelite. The thermocouple wires 16 a and 16 b are insulated from the portion facing the lower end of the foot of the contact plate 17 to the portion facing the upper part of the large diameter portion of the heat insulating tube 19.

A temperature measuring unit is passed through the vibration detecting needle 1 and inserted through an upper end opening of the casing 10. The thermocouple wires 16a and 16b located outside the large diameter portion of the heat insulating pipe 19 are connected to thermocouple contacts 28 and 29 connected to the terminals 26 and 27 of the signal processing circuit 13, respectively. Taper
Upper and lower cuts are provided around the screw holes of the casing 10 corresponding to the screws 11 and 12, respectively.
The inner portions 30, 31 of the respective splits are inwardly deformed by the screwing of the first and the second. As a result, the thermocouple wires 16a, 16b and the thermocouple contacts 28, 29 are firmly pressed against each other, and the temperature measuring unit 1
Fixed to 0. The taper screws 11 and 12 constitute biasing means, and the temperature measuring unit can be pulled out of the casing 10 by loosening the taper screws 11 and 12.

When measuring the operating state of an object to be measured,
While holding the casing 10 by hand, the tip of the vibration detecting needle 1 is pressed against the surface of the object to be measured, and is pushed down to the upper surface of the thermocouple contact plate 17 against the elastic force of the spring portion of the switch fitting 9. Thereby, the contact plate 17 of the thermocouple is also pressed against the object to be measured. Further, the elastic deformation portions 23a and 23b of the thermocouple wires 16a and 16b are deformed inward, and the tip of the vibration detecting needle 1 and the upper surface of the contact plate 17 are pushed to the upper surface of the protection tube 24.

The mechanical vibration of the object to be measured is detected by the vibration detecting needle 1.
Through the vibration transmitting plate 2 and acts on the piezoelectric element 4 as pressure fluctuation. In response, a voltage change occurs in the piezoelectric element 4. The voltage fluctuation is sent from the electrode plates 3 and 5 to the terminals 14 and 15 of the signal processing circuit 13 via the conductors, amplified and detected by the signal processing circuit 13 and calculated into an average value, a peak value, and the like. Are displayed on a display unit (not shown). On the other hand, the temperature signal of the object to be measured is detected by the thermocouple wires 16a and 16b via the contact plate 17, and the thermocouple contacts 28 and
The signal is sent to the terminals 26 and 27 of the signal processing circuit 13 via the line 29, amplified and displayed on the display unit.

[0018]

The present invention has the following specific effects. As described above, according to the present invention, the contact surface of the thermocouple is pressed against the object to be measured with a desired pressing force by the elastic force of the elastic deformation portion formed in the thermocouple wire, so that the number of parts is reduced. The structure becomes simple. If the elastically deformed portion of the thermocouple wire is bent outward, the diameter of the protection tube must be increased. However, in the present invention, since the diameter is bent inward, the diameter of the protection tube does not need to be increased, and the shape becomes compact.

[Brief description of the drawings]

FIG. 1 is a sectional view of a vibration sensor with a temperature sensor in which a temperature sensor according to an embodiment of the present invention is combined with a vibration sensor.

[Explanation of symbols]

 16a, 16b Thermocouple wire 17 Contact plate 19 Insulated tube 20a, 20b Window 21 Gap 23a, 23b Elastic deformation part 24 Protection tube

Claims (1)

(57) [Claims] 1. A thermocouple comprising a contact surface pressed against an object to be measured and thermocouple wires extended from both ends of the contact surface; and the contact surface is located on an upper surface and the thermocouple wire is located on a side surface. An elastically deforming portion which is formed of a heat insulating tube and a protection tube located outside the thermocouple wire, and wherein the contact surface is pushed down to the upper surface of the protection tube, wherein the elastic deformation portion is bent inward in advance by the thermocouple wire. And a concave portion that allows the thermocouple wire to be deformed inside the elastically deformable portion when the contact surface is pressed down is formed on a side surface of the heat insulating tube, and the contact surface of the thermocouple and the heat insulating tube are formed. A gap formed between the temperature sensor and the upper surface of the temperature sensor.