JP2004192979A - Temperature switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature switch made to have higher heat responsiveness by restraining the heat conduction from the outer periphery to a supporting body of a bimetal of a conventional temperature switch. <P>SOLUTION: A plurality of very small supporting protrusions are arranged with a gap on a supporting surface and peripheral wall surface of a supporting body supporting the bimetal. The heat responsiveness of the bimetal is heightened by reducing the contact area for supporting the bimetal by forming an opening having a size of not making the bimetal slip out on a cap covering the bimetal, and arranging a plurality of very small supporting protrusions in the vicinity of the peripheral part of the opening with a gap, and by reducing thermal movement from the bimetal to the supporting body and the cap. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a temperature switch that opens and closes a switch mechanism using a dish-shaped bimetal that senses a temperature by performing a concavo-convex inversion operation at a predetermined temperature and opens and closes an electric circuit according to the temperature.
[0002]
[Prior art]
This type of temperature switch is used to protect an object to be heated, which is heated by an electric heater, from overheating. A temperature switch is arranged so as to be close to or in contact with the object to be heated so that the temperature of the object can be sensed, and the temperature switch opens and closes a power supply circuit of an electric heater for heating the object to be heated. The temperature switch senses the temperature of the object to be heated, and when the temperature becomes equal to or higher than a preset temperature, performs a shut-off operation of a power supply circuit of the electric heater to stop energizing the electric heater. Thus, when the temperature control becomes impossible due to a failure of the temperature controller or the like, the object to be heated can be prevented from being overheated, and the object to be heated and its surroundings can be protected from overheating.
[0003]
In such a temperature switch used for overheating protection of the object to be heated, in order to more reliably protect the object from being overheated, the temperature of the object to be heated can be sensed more quickly so that the temperature change of the object to be heated can be detected more quickly. It is required to improve responsiveness.
[0004]
As a temperature switch satisfying such a demand, a temperature switch as shown in FIGS. 9 to 11 has already been known from Patent Document 1.
[0005]
FIG. 9 is a longitudinal sectional view showing the overall configuration of a conventional temperature switch. The temperature switch 10 includes a cup-shaped main body case 11, a support body 12 placed over the case 11, and a dish-shaped bimetal 13 housed in a recess 12 a provided at an upper end of the support body 12. Opening and closing comprising a cap 14 placed over the upper end of the support 12, a fixed contact 15 a, a movable contact 15 b, and a contact spring 15 c for urging the movable contact 15 b toward the fixed contact 15 a, which are accommodated in the main body case 11. It comprises a contact portion 15 and a drive lever 16 for driving the contact spring 13c by the bimetal 13.
[0006]
As shown in FIG. 10, the cap 14 covering the upper end of the support 12 in which the bimetal 13 is accommodated has an opening 14a of an appropriate size as shown in FIG. A piece 14b is provided.
[0007]
Further, in the recess 12a of the support body 12, a plurality of support projections 12b projecting upward are provided at intervals around the outer periphery on the bottom wall as shown in FIG.
[0008]
The bimetal 13 accommodated in the recess 12a of the support 12 has a circular dish shape, and is upwardly convex at a predetermined temperature or lower, and is inverted when the temperature is higher than a predetermined temperature to become concave. Then, the contact spring 15c is pushed down via the drive lever 16 against its spring force, and the movable contact 15b is separated from the fixed contact 15a to open the electric circuit.
[0009]
Such a conventional temperature switch 10 is placed in contact with or slightly opposite to the temperature of the object to be protected in order to sense the temperature of the object to be protected. At this time, since the opening 14a is provided in the cap 14, the heat of the body to be heated is efficiently transmitted to the bimetal 13 by radiation or convection from the opening 13a. Further, since the bimetal 13 is supported in the recess 12a of the support 12 by contacting with the minute support protrusion 12b provided on the bottom wall surface or the support piece 14b of the cap 14, the bimetal 13 and the support 12 or the contact area with the cap 14 is reduced, and heat conduction from the bimetal 13 to the support 12 or the cap 14 is suppressed, so that the thermal responsiveness of the bimetal 13 is increased.
[0010]
[Patent Document 1]
JP-A-2002-150905, pages 3 and 4, FIG.
[0011]
[Problems to be solved by the invention]
As described above, the conventional temperature switch can considerably fulfill the demand for increasing the thermal responsiveness. However, when the bimetal 13 is offset in the recess 12 a of the support 12, it is close to half of the outer peripheral edge thereof. Is in contact with the peripheral wall of the recess 12a, so that heat conduction to the support 12 via the outer peripheral edge of the bimetal 13 is relatively high, and there is still room for improvement in thermal responsiveness.
[0012]
In view of this point, an object of the present invention is to obtain a temperature switch having higher thermal response by further suppressing the heat conduction from the outer peripheral edge of the bimetal to the support in the conventional temperature switch. is there.
[0013]
[Means for Solving the Problems]
In order to solve such a problem, a first invention is directed to a temperature switch including a dish-shaped heat-sensitive bimetal that performs a concavo-convex reversal operation at a predetermined temperature and an on-off contact that is opened and closed in conjunction with the reversal operation of the bimetal. A support having a recess for accommodating the bimetal which is open at one end, and a cap which covers one end of the support and closes the opening of the recess, and which is supported by the support and the cap. In a temperature switch adapted to support a bimetal housed in a recess of a body from both sides thereof, the bimetal of the support projects in a depth direction and a radial direction of the recess at a bottom wall and a peripheral wall of the recess housing the bimetal. A plurality of minute supporting projections are provided at intervals, and an opening of a size that does not allow the bimetal housed in the recess to come out of the cap is cut open. It is characterized in that the support protrusions of the fine projecting toward the bottom wall of the recess in the vicinity of the opening of the cap is provided at a plurality interval.
[0014]
According to a second aspect of the present invention, there is provided a temperature switch including a dish-shaped heat-sensitive bimetal that performs a concavo-convex reversal operation at a predetermined temperature and a switch mechanism that is opened and closed in conjunction with the reversal operation of the bimetal. A support having a recess for accommodating the bimetal, and a cap covering one end of the support and closing the opening of the recess were provided, and the support and the cap accommodated the recess in the support. In the temperature switch configured to support the bimetal from both surfaces thereof, a plurality of tongue pieces protruding in a radial direction are provided on the outer periphery of the bimetal at intervals, and the cap is engaged with the tongue of the bimetal on the cap. The opening is sized so that the bimetal does not come off.
[0015]
According to these inventions, the contact between the outer peripheral edge of the bimetal and the peripheral wall of the concave portion of the support is performed in a very small point-like area, so that heat conduction from the bimetal to the support is reduced, and the thermal response of the bimetal is reduced. Can be enhanced.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described using an embodiment shown in the drawings.
[0017]
First Embodiment FIG. 1 is a longitudinal sectional view showing a configuration of a temperature switch according to a first embodiment of the present invention. Since this configuration is basically the same as the conventional temperature switch shown in FIG. 5, the same elements are denoted by the same reference numerals.
[0018]
In FIG. 1, reference numeral 10 denotes a main body case 11, a support 12 placed on the case 11, and a circular dish-shaped bimetal 13 housed in a housing recess 12 a provided in the support 12. The cap 14 covers the support 12 from above the recess 12 a, the open / close contact portion 15 including the fixed contact 15 a, the movable contact 15 b, and the contact spring 15 c housed in the case 11. This is a temperature switch composed of an opening / closing lever 16 that transmits a displacement to a switch mechanism 15 and opens and closes a contact.
[0019]
As shown in detail in FIG. 2, the cap 14 has an opening 14a of a size that does not allow the bimetal 13 housed in the recess 12a of the support body 12 to come out similarly to the conventional device. Three small supporting projections 14c protruding toward the recess 12a are provided near the periphery of the 14a at intervals of 120 degrees.
[0020]
As shown in FIG. 3, three small supporting projections 12b projecting upward like the conventional device are provided at intervals of 120 degrees in the vicinity of the outer periphery of the bottom wall of the recess 12a of the support 12 at intervals of 120 degrees. Three minute supporting projections 12d projecting toward the inner diameter side are provided on the peripheral wall of the recess 12a at intervals of 120 degrees. In addition, 12c is a through hole through which the opening / closing lever 16 is inserted.
[0021]
When the thus configured temperature switch 10 of the present invention is used by disposing it with a cap 14 facing upward and facing a heated object (not shown) as shown in FIG. 1, the bimetal 13 is arranged as shown in FIG. The vicinity of the outer periphery of the back surface is supported by being brought into contact with the support protrusion 12b on the bottom wall of the recess 12a of the support 12. Further, since the diameter of the bimetal 13 is selected to be slightly smaller than the diameter of the recess 12a, when the bimetal 13 is positioned in the recess 12a to one side, the outer peripheral edge of the bimetal 13 becomes the peripheral wall of the recess 12a. Abuts on the supporting projection 12c.
[0022]
Therefore, when the bimetal 13 is supported upward as shown in FIG. 1, the bimetal 13 is brought into contact with the small supporting protrusions 12b and 12c in the recess 12a near the outer periphery and the outer periphery thereof. Since the support is supported by the support 12, the contacts form a point contact with each other and the thermal resistance increases, so that the flow of heat from the bimetal 13 to the support 12 is reduced. For this reason, the thermal responsiveness of the bimetal 13 increases.
[0023]
When the temperature switch 10 is installed so that the cap 14 faces downward, as shown in FIG. 5, the vicinity of the outer periphery of the surface of the bimetal 13 comes into contact with the minute supporting projections 14 b protruding inside the cap 14, and Since the bimetal 13 is supported by the cap 14, the bimetal 13 and the cap supporting the bimetal 13 come into contact with each other with a very small area, and the thermal resistance therebetween increases. Since little heat flows from here to the cap side, the thermal responsiveness of the bimetal 13 increases.
[0024]
Therefore, the temperature switch 10 immediately senses a change in the temperature of the object to be heated, and when the temperature of the object to be heated is overheated to a preset temperature or more, the bimetal 13 immediately reverses the unevenness, and the opening / closing lever is opened. By depressing 16, the movable contact 15b is separated from the fixed contact 15a to cut off the power supply circuit of the electric heater for heating the object to be heated, thereby protecting the object to be heated from overheating.
[0025]
Second Embodiment FIG. 6 shows a bimetal 13 according to a second embodiment of the present invention. As shown in the figure, the bimetal 13 in this embodiment is provided with three narrow tongue pieces 13a protruding in the radial direction on the outer peripheral edge of a circular dish-shaped main body at intervals of 120 degrees. The tip of the tongue piece 13a is formed in an arc shape.
[0026]
When such a bimetal 13 is accommodated in the recess 12a of the support 12 of FIG. 1, the tip of the tongue 13a of the bimetal 13 contacts the bottom wall of the recess 12a of the support 12, as shown in FIG. It is supported. In addition, when the position of the bimetal 13 is shifted to one side in the recess 12a, the tip of the tongue 13a comes into contact with the peripheral wall of the recess 12a of the support.
[0027]
Then, when the direction of the temperature switch 10 is downward, as shown in FIG. 8, the vicinity of the tip of the tongue piece 13 a of the bimetal 13 contacts and is supported by the periphery of the opening 14 a of the cap 14.
[0028]
Therefore, also in this embodiment, since the bimetal 13 is supported in contact with the support 12 or the cap 14 via the tongue 13a in any direction, the contact area between the bimetal and the support or the cap is reduced. The thermal responsiveness of the bimetal 13 can be enhanced by decreasing the thermal resistance between the bimetal 13 and the heat flow from the bimetal to the support.
[0029]
When the bimetal of this embodiment is used, it is necessary to provide the support protrusions 12b and 12c in the recess of the support body 12 and the support protrusion 14b on the periphery of the opening of the cap 14, which are provided in the first embodiment. Therefore, the configuration can be simplified as compared with the first embodiment.
[0030]
Further, the bimetal 13 in the second embodiment has a larger outer diameter by the provision of the tongue piece 13a, so that the displacement amount at the time of the inversion operation can be larger than that of the bimetal without the tongue piece. The opening distance of the movable contact of the section can be increased, and the electrical insulation performance of the temperature switch can be improved.
[0031]
【The invention's effect】
According to a first aspect of the present invention, a plurality of minute supporting projections projecting in the depth direction and the radial direction of the recess are provided on the bottom wall and the peripheral wall of the recess accommodating the bimetal of the support at intervals. The cap placed over the top of the cap is opened with an opening of a size that does not allow the bimetal contained in the recess to escape, and a plurality of micro-supporting projections projecting toward the recess near the periphery of the opening of the cap at intervals. The bimetal is supported in contact with the support or the cap in a point-like manner, and the heat transfer between the bimetal and the support becomes extremely small, so that the thermal responsiveness of the bimetal can be improved, There is an effect that a high temperature switch can be obtained.
[0032]
According to the second aspect of the present invention, a plurality of tongue pieces protruding in the radial direction are provided on the outer periphery of the bimetal at intervals, and the cap is engaged with the tongue of the bimetal and the bimetal comes off. Since the opening having a size without the cutout is cut out, the contact area between the bimetal and the support or the cap is small as in the first invention, the thermal responsiveness of the bimetal can be improved, and the responsiveness is high. An effect that can be used as a temperature switch is obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a configuration of a temperature switch according to a first embodiment of the present invention.
FIGS. 2A and 2B show details of a cap used in the temperature switch of the first embodiment, wherein FIG. 2A is a plan view thereof, and FIG. 2B is a sectional view taken along line AA in FIG.
3A and 3B show details of a support used for the temperature switch of the first embodiment, where FIG. 3A is a plan view and FIG. 3B is a cross-sectional view taken along line AA in FIG.
FIG. 4 is a longitudinal sectional view of a main part in a state where the temperature switch of the first embodiment is used upward.
FIG. 5 is a longitudinal sectional view of a main part in a state where the temperature switch of the first embodiment is used downward.
FIG. 6 is a plan view showing a bimetal according to a second embodiment of the present invention.
FIG. 7 is a longitudinal sectional view of a main part in a state where the temperature switch of the second embodiment is used upward.
FIG. 8 is a longitudinal sectional view of a main part in a state where the temperature switch of the second embodiment is used downward.
FIG. 9 is a longitudinal sectional view showing a conventional temperature switch.
FIG. 10 is a perspective view showing a cap in a conventional temperature switch.
11A and 11B show a conventional temperature switch support, and FIG. 11A is a plan view and FIG. 11B is a cross-sectional view taken along line AA in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Temperature switch 11 Main body case 12 Supporting body 12b, 12d Supporting projection 13 Bimetal 13a Tongue piece 14 Cap 14a Opening 14b Supporting projection 15 Opening / closing contact part 16 Opening / closing lever

Claims (2)

A temperature switch comprising: a dish-shaped heat-sensitive bimetal that performs a concavo-convex reversal operation at a predetermined temperature; and a switch mechanism that is opened and closed in conjunction with the reversal operation of the bimetal. And a cap that covers one end of the support and closes the opening of the recess. The support and the cap support the bimetal housed in the recess of the support from both sides. In the temperature switch, a plurality of minute support pieces projecting in a depth direction and a radial direction of the recess are provided on a bottom wall and a peripheral wall of the recess accommodating the bimetal of the support at intervals, and the cap is provided. The cap is pierced into the bottom wall of the recess near the opening of the cap. Temperature switch, characterized in that provided at a plurality intervals small support pieces. A temperature switch comprising: a dish-shaped heat-sensitive bimetal that performs a concavo-convex reversal operation at a predetermined temperature; and a switch mechanism that is opened and closed in conjunction with the reversal operation of the bimetal. And a cap that covers one end of the support and closes the opening of the recess. The support and the cap support the bimetal housed in the recess of the support from both sides. In the temperature switch described above, a plurality of tongue pieces protruding in the radial direction are provided on the outer periphery of the bimetal at intervals, and the cap is engaged with the tongue of the bimetal so that the bimetal does not come off. A temperature switch characterized by having an opening at the bottom.

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