JPH0431568Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a temperature sensor that is attached to an electrical appliance to detect an abnormal temperature rise in the electrical appliance.

[Conventional technology]

The researchers first attached a piece of metal with good thermal conductivity to a plastic housing so that the metal piece was exposed, then attached the plastic housing to an electrical appliance.
When this metal piece receives heat, the metal wire attached to this metal piece that has thermal deformability deforms due to conduction heat and comes into electrical contact with the fixed contact provided in the housing, causing a current to flow. We proposed a temperature sensor that would issue an alarm when the flow occurred.

[Problems with conventional technology]

However, in such temperature sensors, when there is a gap between the temperature sensing part made of a metal with good thermal conductivity and the object to be measured, such as a bus duct or cable, this gap There is a problem in that even a small amount of heat inhibits the conduction of heat from the object to be measured to the temperature sensing part of the temperature sensor, resulting in a significant drop in detection performance.

[Purpose of invention]

An object of the present invention is to provide a temperature sensor in which the temperature sensing part can always be kept in good contact with the object to be measured, even if the surface of the object to be measured is uneven.

[Means for solving the problem] The temperature sensor of the present invention has a permanent magnet and a temperature-sensing part made of a metal with good thermal conductivity mounted inside a casing made of a non-magnetic material. ,
In the temperature sensor in which one side of each of the permanent magnet and the temperature-sensing section is exposed, the temperature-sensing section has a tip with a narrow diameter, and the tip is perforated in the casing. It is housed in the casing and is exposed in a state that protrudes from the hole. A presser spring is attached to the back of the housing, and a permanent magnet plate is installed in the insertion hole provided on both sides of the protruding temperature sensing part. are inserted through the permanent magnet plates, magnetic metal plates are magnetically attached to both sides of each of the permanent magnet plates, and through holes are bored in each of the metal plates and the permanent magnet plates. The shaft core inserted into the through hole is housed in an elongated hole perpendicular to the magnetic surface of the housing within the housing, and the thickness of the shaft core is the same as that of the metal plate. It is characterized in that it is smaller than the diameter of the through-hole, and the thickness of the axis is smaller than the elongated hole provided in the housing.

[Effect]

In the temperature sensor configured as described above, a force is constantly applied to the temperature sensing portion in the direction of pushing it toward the outside of the housing by the spring on the back surface, so that it is possible to maintain a good contact state with the object to be measured.

In addition, the metal plates provided on both sides of the temperature-sensing part shift independently with respect to the permanent magnet around the inserted shaft core, and the shaft core can also move inside the elongated hole. Even if the surface of the heated body is uneven, the temperature sensor is moved along the surface of the body to be measured while in contact with the body, searching for a part where there is good contact between the two.
The temperature sensor can be magnetically attached and fixed at that position.

Furthermore, the magnetic metal plates attached to both sides of the permanent magnet have the effect of increasing the magnetic force of the permanent magnet.

〔Example〕

Next, embodiments of the temperature sensor of the present invention will be described in detail using figures.

As shown in Fig. 1, the temperature sensor 1 of the present invention has a casing 2 made of a non-magnetic material, a temperature-sensing part 3 made of a metal with good thermal conductivity, and the casing magnetically attached to the object to be measured. A permanent magnet 4 is mounted so that a part of it is exposed from one surface of the housing as shown in FIG.

The shape of the casing 2 itself is not particularly limited, but in this embodiment it consists of a plastic box-shaped part 5 and a lid part 6, and the box-shaped part 5 has a partitioned space as shown in the figure. A copper rod 8 made of a metal with good thermal conductivity and having a narrow end diameter is attached to the temperature sensing part insertion hole 7 in the middle part. As shown in the figure, the entrance of the temperature sensing part insertion hole 7 is narrowed to match the thinner part of the copper rod 8.
The narrowed edge of the entrance serves as a stopper to prevent the copper rod 8 from jumping out.

A spring 9 is installed between the copper rod 8 and the lid 6 on the back of the housing, and this spring 9 always acts to press the copper rod 8 against the object to be measured. ing.

The permanent magnet 4 is inserted into insertion holes 10 and 10' provided on both side edges of the housing 2.

As shown in FIG. 3, iron plates 11, which are magnetic materials, are magnetically attached to both sides of the permanent magnet 4, and a through hole 20 of the permanent magnet 4 is formed in the permanent magnet 4, and the iron plate 11 is provided in the center of the iron plate 11. A through hole 12 is formed in the iron plate 11, and a shaft core 13 having a smaller diameter than the through hole 12 in the iron plate 11 is inserted into the through hole 12. The permanent magnet 4 and the iron plate 11 are inserted through the insertion holes 10 and 10' of the housing 2, respectively, and the shaft core 13 is housed in a long hole 14 in the housing perpendicular to the surface of the temperature-measuring object. A shape memory alloy wire 15 is led out from the side of the copper rod 8, and a fixed contact 16 is provided near the shape memory alloy wire 15 inside the housing.
An electric wire is connected there, and its lead wire 1
7 is led out to the outside of the temperature sensor via a miniature light bulb 18.

Next, to explain how to use this temperature sensor, bring the exposed surface of the temperature sensor's permanent magnet 4 into contact with the object to be measured, such as a bus duct, and move it back and forth and left and right while keeping it in contact with the surface of the temperature sensor. Find and fix the part where the exposed surface has the best contact with the object to be measured. And the temperature sensor of this invention is iron plate 1
Since the hole diameter of the through hole 12 of the housing 1 and the hole diameter of the elongated hole 14 of the housing 2 are both larger than the diameter of the shaft core 13, the permanent magnet 4 and the iron plate 11 can be independently displaced as shown in FIG. In addition, since the shaft core itself can move within the long hole of the housing, it can be moved freely along the unevenness of the surface of the object to be measured, and the temperature sensing part of the temperature sensor is applied to the object to be measured by magnetic force. This allows for tighter adhesion. Further, the temperature sensing portion of the temperature sensor can be kept in close contact with the object to be measured at all times due to the elasticity of the spring located behind it.

When the temperature of the body to be measured to which the temperature sensor is attached rises abnormally, the shape memory alloy wire 15 bends due to the heat conducted to the copper rod 8 which is the temperature sensing part, and comes into contact with the fixed contact 16. Then, the miniature light bulb 18 lights up, and an alarm device or the like (not shown) connected to the lead wires 17, 17' can be activated.

Incidentally, a plate-shaped spring 19 as shown in FIG. 4 may be used instead of the spring attached to the back surface of the temperature sensing section.

In addition, if a miniature light bulb 18 is connected to a fixed contact as in the embodiment or to the middle of the lead wire connecting the temperature sensing part to the outside, it is possible to easily check abnormally heated parts of electrical appliances etc. from a distance. can.

[Effect of idea]

As mentioned above, in the temperature sensor of the present invention, the temperature sensing part and the permanent magnet attached to the temperature sensor are movable to adapt to the unevenness of the surface of the object to be measured. This is a useful device that can bring the two into a good contact state and fully exhibit its detection performance.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the temperature sensor of the present invention. Figure 2 is a sectional view along A-A' of Figure 1;
The figure is an explanatory view of the same portion, and FIG. 4 is a sectional view of another embodiment. 1...Temperature sensor, 2...Housing, 3...Temperature sensing part, 4...Permanent magnet, 5...Box shaped part, 6...Lid part, 7...Temperature sensing part insertion hole, 8... Copper rod, 9...Spring, 10, 10'...Through hole, 11...Iron plate, 12...Through hole in iron plate, 13...Axle core, 14
... Long hole, 15 ... Shape memory alloy wire, 16 ... Fixed contact, 17, 17' ... Lead wire, 18 ... Miniature light bulb, 19 ... Spring, 20 ... Permanent magnet through hole.

Claims (1)

[Scope of utility model registration request] A permanent magnet and a temperature-sensing section made of a metal with good thermal conductivity are mounted inside a casing made of a non-magnetic material. In a temperature sensor that is designed to be exposed, the temperature sensing part has a narrow diameter at its tip, and the tip is exposed with the tip protruding from a hole drilled in the casing. A presser spring is attached to the back of the permanent magnet plate, and permanent magnet plates are inserted into the insertion holes provided on both sides of the protruding temperature-sensing part. Magnetic metal plates are magnetically attached to both sides, through-holes are bored in each of the metal plates and the permanent magnet plate, and the shaft core inserted into these through-holes is inserted into the housing. It is housed in an elongated hole perpendicular to the magnetic surface of the casing in the body, and the thickness of the axis is smaller than the diameter of the through hole penetrating the metal plate, and A temperature sensor characterized in that the thickness of the shaft core is smaller than the elongated hole provided in the housing.