JP2022178190A - thermostat - Google Patents

Abstract

A thermostat that is compact and has excellent insulation properties is provided.
A thermostat (1) includes a cylindrical case (11), a lid body (12) fitted to an open end of the cylindrical case (11) to close the open end, and a lid body (12) which is overlapped and curved in a dome shape. A bimetal 13 formed to form a convex surface by pressing, a movable terminal 14 provided inside the cylindrical case 11, a fixed terminal 15 in contact with the movable terminal 14, and a hole formed in the cover 12 so as to be movably inserted. , a pin 16 arranged between the convex surface of the bimetal 13 and the movable terminal 14 . A recessed portion and a projected portion are formed in the peripheral portion of the open end of the cylindrical case 11 and the lid 12 so as to face each other.
[Selection drawing] Fig. 1

Description

TECHNICAL FIELD The present invention relates to a thermostat that switches contacts on and off by deformation of a dome-shaped bimetal, and more particularly to a technique for improving insulation of a thermostat.

Some thermostats include a bimetal curved in a dome shape to form a convex surface, a movable terminal, and a fixed terminal in contact with the movable terminal. This bimetal deforms with changes in temperature, and its convex surface protrudes into a concave surface. The movable terminal is displaced in conjunction with the deformation of the bimetal from the convex surface to the concave surface, and the movable terminal is separated from the fixed terminal.

For example, in the thermostat disclosed in Patent Document 1, the annular projecting portion of the inner lid is movably inserted inside the peripheral wall portion of the base member, and inside the annular projecting portion of the inner lid, a terminal on the movable side and the terminal on the movable side Place the terminal on the fixed side that contacts the terminal of , put the inner lid on the terminal on the movable side, put the reversing disk (bimetal) on the upper side of the inner lid, and put the cap on the base member and the reversing disk. there is When the projection direction of the reversing disc is reversed due to temperature change, the movable side terminal is displaced by being pushed by the reversing disc through the inner lid, and the movable side terminal is separated from the fixed side terminal. In addition, since the inner lid is provided, the insulation distance from the terminal on the movable side to the cap extends from the terminal on the movable side through the lower end of the inner lid to the gap between the outer periphery of the inner lid and the peripheral wall of the base member. , and good insulation is maintained between the terminal on the movable side and the cap.

JP-A-2008-123959

Here, in Patent Document 1, the insulation distance between the movable-side terminal and the cap is increased by providing the inner lid to maintain good insulation between the movable-side terminal and the cap. The annular projecting portion of the inner lid is inserted inside the peripheral wall of the inner lid, and the movable-side terminal and the fixed-side terminal are arranged inside the annular projecting portion of the inner lid (see paragraph 0025 of Patent Document 1, etc. ), the thermostat becomes larger.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a thermostat capable of achieving downsizing while ensuring excellent insulation properties in consideration of the above circumstances.

A thermostat according to one aspect of the present invention includes a cylindrical case, a lid fitted to an open end of the cylindrical case to close the open end, and a lid provided over the lid and curved in a dome shape. a bimetal that forms a convex surface by squeezing, a movable terminal provided inside the cylindrical case and a fixed terminal in contact with the movable terminal, and a fixed terminal that is movably inserted into a hole formed in the lid, and the bimetal is a convex surface and a pin disposed between the movable terminal; when the bimetal is deformed due to a change in temperature, the convex surface of the bimetal is depressed to become a concave surface; The movable terminal is displaced and separated from the fixed terminal, a recess is formed in the peripheral edge of the open end of the cylindrical case, and the lid body is formed with a projection that is combined with the recess and faces the recess. There is.

According to the thermostat according to the present invention, downsizing can be achieved while ensuring excellent insulation.

1 is a longitudinal sectional view showing a thermostat according to an embodiment of the invention; FIG. It is a figure used in order to demonstrate the operation|movement of the thermostat of this embodiment. It is a figure which shows the insulation distance from the fixed terminal in the thermostat of this embodiment to a cap. FIG. 5 is a diagram showing an insulation distance from a fixed terminal to a cap in a thermostat of a comparative example; (A) and (B) are vertical cross-sectional views showing respective modifications of the thermostat of the present invention.

A thermostat according to one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing a thermostat according to one embodiment of the invention. As shown in FIG. 1 , in the thermostat 1 of the present embodiment, a disk-shaped cover 12 is fitted to the upper open end of a cylindrical cylindrical case 11 . A lid 12 closes the upper open end of the cylindrical case 11, and a disk-shaped bimetal 13 curved in a dome shape to form a convex surface 13a is superimposed on the lid 12. As shown in FIG. A movable terminal 14 and a fixed terminal 15 in contact with the movable terminal 14 are provided inside the cylindrical case 11 . A cylindrical pin 16 is movably inserted into a hole 12 a formed in the lid 12 , and the pin 16 is arranged between the convex surface 13 a of the bimetal 13 and the movable terminal 14 . Furthermore, the lid 12 is covered with a cap 17 , and the bimetal 13 is exposed through a central hole 17 a of the cap 17 . A bottom body 18 is fitted to the lower open end of the cylindrical case 11 so that the bottom body 18 closes the lower open end of the cylindrical case 11 . A pair of lead terminals 19 and 20 are provided on the lower surface side of the bottom body 18 and each lead terminal 19 and 20 extends from the inside to the outside of the tubular case 11 . One lead terminal 19 is connected to the movable terminal 14 via an L-shaped connection terminal 21 , and the other lead terminal 20 is connected to an L-shaped fixed terminal 15 .

A fitting portion 12b having a diameter smaller than the outer diameter of the lid 12 and substantially equal to the inner periphery (inner diameter) of the cylindrical case 11 is formed in the lower portion of the lid 12. An annular protrusion 12c is formed on the side. The annular protrusion 12c has a triangular cross-sectional shape in a side view that protrudes downward over the entire circumference.

A peripheral recess 11a at the upper open end of the cylindrical case 11 has a triangular cross-sectional shape in a side view that is recessed downward over the entire circumference.

The fitting portion 12b of the lid 12 is inserted inside the upper opening end of the cylindrical case 11, and the downward projecting triangular shape of the annular projection 12c of the lid 12 and the downward peripheral recess 11a of the cylindrical case 11 are formed. The annular projection 12c of the lid 12 and the peripheral recess 11a of the cylindrical case 11 face each other.

A circular recess 12d is formed in the upper portion of the lid 12, and an annular step 12e is formed on the upper inner circumference of the recess 12d. The outer peripheral edge of the disk-shaped bimetal 13 is fitted into the annular step 12e, and the outer peripheral edge of the bimetal 13 is pressed by the cap 17 to fix the bimetal 13 therein. At the same time, the cap 17 presses the annular protrusion 12c of the lid 12 against the peripheral recess 11a of the cylindrical case 11 to abut it.

The cap 17 extends from the annular stepped portion 12e of the lid body 12 to the stepped portion 11c on the outer periphery of the cylindrical case 11 through the outer periphery of the lid body 12, and is engaged with the stepped portion 11c to integrate the cylindrical case 11 and the lid body 12 together. support it.

The movable terminal 14 includes a plate-like portion 14a and a contact 14b that are elastically deformable up and down. 15a.

The L-shaped connection terminal 21 penetrates through the bottom body 18 and is connected to one lead terminal 19 . The L-shaped fixed terminal 15 is connected to the other lead terminal 20 through the bottom body 18 .

The tubular case 11, lid 12, pin 16, and bottom 18 are made of an insulating material such as synthetic resin. Also, the bimetal 13, the movable terminal 14, the fixed terminal 15, the cap 17, and the lead terminals 19 and 20 are made of a conductive material such as metal.

In the thermostat 1 having such a configuration, for example, when the ambient temperature is room temperature, the bimetal 13 is curved like a dome as shown in FIG. In this state, the upper end of the pin 16 is slightly separated from the convex surface 13a of the bimetal 13, the lower end of the pin 16 is in contact with the plate-like portion 14a of the movable terminal 14, and the plate-like portion 14a of the movable terminal 14 is not deformed. A contact 14 b of the movable terminal 14 contacts a contact 15 a of the L-shaped fixed terminal 15 . Therefore, the lead terminals 19 and 20 are connected to each other via the L-shaped connection terminal 21, the movable terminal 14, and the L-shaped fixed terminal 15, and the lead terminals 19 and 20 are in a conductive state. Become.

Further, when the ambient temperature changes from room temperature to high or low temperature, the direction of curvature of the bimetal 13 is reversed as shown in FIG. 2, and the lower surface of the bimetal 13 becomes the concave surface 13b. At this time, the upper end of the pin 16 is pushed downward by the concave surface 13b of the bimetal 13, and the lower end of the pin 16 pushes down the plate-like portion 14a of the movable terminal 14, causing the plate-like portion 14a of the movable terminal 14 to bend. As a result, the contact 14b of the movable terminal 14 is separated from the contact 15a of the L-shaped fixed terminal 15. As shown in FIG. Therefore, the lead terminals 19 and 20 are cut off.

In this manner, the lower surface of the bimetal 13 becomes a convex surface 13a or a concave surface 13b according to changes in the ambient temperature, the contact 14b of the movable terminal 14 is brought into contact with and separated from the contact 15a of the L-shaped fixed terminal 15, and each lead terminal 19 , 20 are conductive or disconnected, and the function of the thermostat 1 is achieved.

Here, it is preferable that the thermostat 1 has high insulation. For high insulation, the insulation distance (creepage distance), ie the shortest distance along the surface of the insulator between two conductors, must be increased.

In the thermostat 1 of this embodiment, as shown in FIG. 3, the creepage distance from the fixed terminal 15 to the cap 17 is the shortest distance. The insulation distance (creeping distance) S from the fixed terminal 15 to the cap 17 is determined by the distance s1 along the inner peripheral wall of the cylindrical case 11 indicated by the thick line arrow, the annular projection 12c of the lid 12 and the peripheral concave portion of the cylindrical case 11. It is the sum of the distance s2 indicated by the thick arrow between 11a. As described above, the downwardly projecting triangular shape of the annular protrusion 12c of the lid 12 and the downwardly recessed triangular shape of the peripheral recess 11a of the tubular case 11 are combined to face each other. There is a slight gap between the downwardly projecting triangular shape of the annular projection 12c of the lid 12 and the downwardly recessed triangular shape of the peripheral edge recess 11a of the tubular case 11 . Therefore, the portion between the annular protrusion 12c of the lid 12 and the peripheral recess 11a of the cylindrical case 11 is bent in a triangular shape, and the distance s2 of this triangular path becomes relatively long.

FIG. 4 is an enlarged sectional view showing a comparative example of a thermostat. In the thermostat 1A of the comparative example shown in FIG. 4, the peripheral edge portion 11f of the upper opening end of the cylindrical case 11 is flattened over the entire circumference, and the annular portion of the lid body 12 abuts on the peripheral edge portion 11f of the cylindrical case 11. 12f is also flattened all around. In this case, the insulation distance (creeping distance) S′ from the fixed terminal 15 to the cap 17 is the distance s1 indicated by the thick arrow along the inner peripheral wall of the cylindrical case 11, and the distance s3 indicated by the thick arrow between the peripheral edge portions 11f. However, the distance s3 is the distance of the straight path, and the distance s3 of this straight path is shorter than the distance s2 of the triangular path. Therefore, the insulation distance S of the present embodiment is longer than the insulation distance S' of the comparative example, and the thermostat 1 of the present embodiment has better insulation than the thermostat 1A of the comparative example.

According to experiments, in the thermostat 1A of the comparative example, when the insulation distance S' between the fixed terminal 15 and the cap 17 is 4.8 mm, a discharge phenomenon occurs at a lightning surge of 4.8 kV. On the other hand, in the thermostat 1 of the present embodiment, the insulation distance S between the fixed terminal 15 and the cap 17 is longer than the insulation distance S', so the discharge phenomenon did not occur even with a lightning surge of 4.8 kV. .

When the annular protrusion 12c of the lid 12 and the peripheral recess 11a of the cylindrical case 11 are combined and opposed to each other as in the thermostat 1 of the present embodiment, the gap between the annular protrusion 12c and the peripheral recess 11a is entirely can be significantly narrowed. That is, when the flat annular portion 12f of the lid body 12 and the flat peripheral edge portion 11f of the cylindrical case 11 are brought into contact with each other as in the thermostat 1A of the comparative example, the insulating distance S' is short, so that the insulating property is increased. To achieve this, the distance between the annular portion 12f and the peripheral edge portion 11f must be relatively large. However, in the thermostat 1 of this embodiment, since the insulation distance S is longer than the insulation distance S', it is not necessary to provide a large space between the annular portion 12f and the cylindrical case 11 as in the thermostat 1A. From this point, the thermostat 1 can be made smaller than the thermostat 1A of the comparative example, and the thermostat 1 of the present embodiment can be superior in insulating property to the thermostat 1A of the comparative example.

In addition, in the thermostat 1 of the present embodiment, the movable terminal 14 and the fixed terminal 15 are provided inside the cylindrical case 11, and unlike Patent Document 1, the inner lid is not provided. be able to.

In the above-described embodiment, the cross-sectional shape of the annular protrusion 12c of the lid 12 and the cross-sectional shape of the peripheral recess 11a of the cylindrical case 11 are combined to form opposing triangular shapes. They may be combined into opposing rectangular shapes or wavy shapes.

Further, as shown in FIG. 5A, the cross-sectional shape of the annular protrusion 12c of the lid 12 and the cross-sectional shape of the peripheral recess 11a of the cylindrical case 11 are formed by a plurality of continuous triangular shapes that are combined with each other and face each other. Alternatively, as shown in FIG. 5B, the cross-sectional shape of the annular protrusion 12c of the lid 12 and the cross-sectional shape of the peripheral recess 11a of the cylindrical case 11 are formed by a plurality of rectangular shapes that are continuous and combined with each other. You may make it a shape which opposes. As a result, the insulation distance S between the fixed terminal 15 and the cap 17 is increased while the thermostat 1 is kept small, and the insulation between the fixed terminal 15 and the cap 17 is further increased. The airtightness between the body 12 and the cylindrical case 11 can be made higher.

Moreover, the configuration of the above embodiment described with reference to FIGS. 1 to 5 is merely an example of the present invention, and is not intended to limit the present invention to this configuration. For example, in the above-described embodiment, the cylindrical case 11 is cylindrical, but the cylindrical case 11 is not limited to this, and may have other shapes such as a polygonal cylindrical shape. In this case, each member such as the lid 12 used in combination with the cylindrical case 11 has a shape corresponding to the shape of the cylindrical case 11 .

1 thermostat 11 cylindrical case 12 lid 13 bimetal 14 movable terminal 15 fixed terminal 16 pin 17 cap 18 bottom 19 lead terminal 20 lead terminal 21 connection terminal

Claims (3)

a cylindrical case;
a lid fitted to the open end of the cylindrical case to close the open end;
a bimetal that is superimposed on the lid and curved in a dome shape to form a convex surface;
a movable terminal provided inside the cylindrical case and a fixed terminal in contact with the movable terminal;
a pin movably inserted into a hole formed in the lid and arranged between the convex surface of the bimetal and the movable terminal;
When the bimetal is deformed due to a change in temperature, the convex surface of the bimetal becomes depressed and becomes a concave surface, the pin is pushed by the concave surface and moves, and the movable terminal is displaced by the pin and separated from the fixed terminal,
A thermostat in which a concave portion is formed in the peripheral edge portion of the open end of the cylindrical case, and a projection portion is formed in the cover body so as to be combined with the concave portion and face the concave portion. 2. The thermostat according to claim 1, wherein the concave portion and the protrusion have triangular, rectangular, or corrugated cross-sectional shapes that are combined and opposed to each other. A plurality of recesses are formed along the periphery of the opening end of the cylindrical case, and the lid body has a plurality of protrusions that are combined with the plurality of recesses and face each other. 3. A thermostat according to claim 1 or 2, wherein are formed side by side.

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