JPH0443947Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a temperature detection device suitable for use in a cooker or a heater such as a rice cooker.

Conventional technology and its problems The most well-known conventional temperature detection device is the center thermo system, but with this system it is impossible to control the temperature of the pan, which is the body to be tested. . As a conventional technology capable of temperature control, there is a known technology that detects the temperature at two locations, the bottom and the side of the pan, and uses the detection signal to control the temperature. This has the drawback of doubling the number of parts and increasing costs.

Purpose of the present invention Therefore, the present invention solves the above-mentioned conventional technical problems, detects and controls the temperature of a cooking device such as a rice cooker or a heater with high precision, and has a simple configuration. The object is to provide a temperature detection device that is simple and easy to assemble.

Structure of the present invention In order to achieve the above object, the present invention includes a movable body that moves forward and backward depending on the presence or absence of a warm body to be tested, a temperature sensing element that detects the temperature of the warm body to be tested, and a movable body that supports the movable body so that it can move back and forth. A temperature detection device comprising a coil spring, a case for housing the movable body and the coil spring, and a switch that is turned on and off by forward and backward movement of the movable body, wherein the movable body is made of ceramic or heat-resistant resin. It is formed into a cylindrical shape having an upper surface that is in contact with the hot body to be tested, a bottom surface that faces the upper surface, and side surfaces, and a metal plate with good thermal conductivity is attached to the upper surface. , the temperature sensing element is brought into contact with the inner surface of the metal plate through the upper surface of the movable body, and the coil spring is arranged in a space created between the outer circumference of the side surface of the movable body and the inner circumference of the case. The movable body is supported within the movable body, and the switch is a combination of a magnet and a magnetically responsive switch, and the magnet and the magnetically responsive switch include:
The bottom surface of the movable body and the inner bottom surface of the outer case are respectively provided so as to operate according to the distance between the bottom surface of the movable body and the inner bottom surface of the case that faces the bottom surface with a space therebetween. It is characterized by a corresponding arrangement.

Embodiment FIG. 1 is a partial front sectional view of a temperature detection device according to the present invention realized for use in a rice cooker, and FIG. 2 is a partial front sectional view of the same in a state of use.
In the figure, 1 is a case formed in the shape of a bottomed box;
2 is a heater. The outer periphery of the upper end of the case 1 is fixed to the heater 2 so as to substantially coincide with the surface of the heater 2. 3 is a cylindrical movable body fitted inside the case 1; 4 is a coil spring wrapped around the outside of the movable body 3 to support the movable body 3 so that it can move forward and backward inside the case 1; 5 is a coil spring; This is a stopper that prevents the movable body 3 from jumping out through the upper opening of the case 1 under the elastic force of the coil spring 4, and is made of a metal material or the like with poor thermal conductivity.

The case 1 and the movable body 3 are made of, for example, a ceramic material such as alumina porcelain or a heat-resistant resin such as a phenol alkyl resin, in order to suppress as much as possible the heat generated in the heater 2 from being transmitted to the movable body 3 side. .

The movable body 3 is a part that detects the presence or absence of a hot body to be tested 6 (FIG. 2) such as a pan for a rice cooker, and when no hot body to be tested 6 is placed on its upper surface 301 side, , is lifted upward as shown in the figure by the elastic force of the coil spring 4,
When the warm body 6 to be tested is placed (FIG. 2), the coil spring 4 contracts and descends. The upper surface 3
A metal plate 7 having good thermal conductivity, such as aluminum, is provided in surface contact with the surface of 01.
The temperature sensing element 8 is thermally coupled to the inner surface of the metal plate 7 through a notch 302 provided in the upper surface 301. As the temperature sensing element 8, an NTC thermistor, a PTC thermistor, or the like can be used. Among these, glass-sealed thermistors are particularly preferred. This is because glass-sealed thermistors have excellent moisture resistance and stability.

A magnet 9 is fitted into the approximate center of the bottom surface 303 of the movable body 3, which faces the top surface 301. The structure is such that they face each other.

The magnet 9 and the magnetically responsive switch 10
The switch is turned on and off by the forward and backward movement of the movable body 3, and functions as a switch that opens and closes a temperature detection circuit including a temperature sensing element 8. When a normally closed type reed switch is used as the magnetic response switch 10, for example, are electrically connected in parallel to the temperature sensing element 8, and in the case of a normally open type, connected in series. As shown in FIG. 3, the structure for drawing out the lead wires of the temperature sensing element 8 and the magnetically responsive switch 10 is a two-wire type in which two lead wires are connected in parallel or in series inside the temperature detecting device in advance. , as shown in FIG. 4, the lead wires of the temperature sensing element 8 and the magnetically responsive switch 10 are drawn out independently of each other, or as shown in FIG. 5, only one lead wire is commonly connected inside the device. However, various embodiments can be considered, such as a three-wire system in which three lead wires, this common wire and the remaining two lead wires, are drawn out.

When the hot body 6 to be tested does not exist on the metal body 7 provided on the upper surface 301 of the movable body 3, the movable body 3 is at the upper limit position (FIG. 1) controlled by the stopper 5, and therefore the magnetic The responsive switch 10 does not respond to the magnetism from the magnet 9, and the magnetically responsive switch 10
If a normally closed reed switch is used, it will turn on. Therefore, the temperature sensing element 8 is short-circuited by the magnetically responsive switch 10, current no longer flows through the temperature sensing element 8, and the temperature sensing operation is stopped. That is, if the temperature-tested body 6 is not present and the temperature measurement operation is unnecessary, the temperature detection circuit is shut off.

On the other hand, when the temperature-tested body 6 is placed and a temperature measurement operation becomes necessary, the movable body 3 descends against the coil spring 4, and the magnet 9 approaches the magnetic response switch 10 as shown in FIG. , the magnetic response switch 10 is turned off in response to the magnetism from the magnet 9, current flows through the temperature sensing element 8, and a temperature detection signal is taken out. The temperature of the temperature-tested body 6 is detected by a temperature sensing element 8 through a metal plate 7 that is directly thermally coupled thereto. Temperature control is possible by controlling the heat generation temperature of the heater 2 using this temperature detection signal.

As mentioned above, the temperature detection device according to the present invention has the following features:
The presence or absence of the hot body 6 to be tested is detected by the movement of the movable body 3 back and forth, and the distance between the magnet 9 and the magnetic response switch 10 is varied by the movement of the movable body 3 back and forth.
Since the magnetic response switch 10 is turned on and off, and the temperature detection circuit is opened and closed by turning the magnetic response switch 10 on and off, the temperature sensing element 8 made of an NTC thermistor or PTC thermistor is used to detect the temperature to be measured. Continuously detects the temperature of the body 6,
Temperature control can be performed with high precision. Moreover, since the temperature sensing element 8 is attached to the metal plate 7 which is directly thermally coupled to the temperature object 6 to be measured, the temperature of the bottom surface of the pan, which is the temperature object 6 to be measured, can be sensitively detected.

In addition, since the case 1 and the movable body 3 are made of a ceramic material such as alumina porcelain with good heat insulation properties or a heat-resistant resin such as a phenol alkyl resin, the temperature sensing element is connected from the heater 2 through the case 1 and the movable body 3. It becomes possible to suppress the heat conduction transferred to the temperature sensing element 8 and to sensitively detect the temperature of the object 6 to be measured through the metal plate 7 which is directly thermally coupled to the object 6.

Furthermore, a magnet 9 and a magnetic response switch 10
Since it is mounted at the bottom far from the heater 2, it is less affected by heat and reliability is improved accordingly. In addition, since the magnetically responsive switch 10 is used, which is a reed switch that is less susceptible to the influence of the atmosphere and has superior switching functions compared to a normal contact switch, Operates stably even in ambient conditions. Moreover, the case 1, the movable body 3, the coil spring 4, the temperature sensing element 8, the magnet 9, and the magnetic response switch 1
Temperature detection and control can be performed with a simple configuration that only includes 0, and there are also advantages such as a temperature detection device that is structurally simple, easy to assemble, and inexpensive.

In the above embodiment, the magnet 9 is attached to the movable body 3 and moved, and the magnetic response switch 10 is fixed, but in contrast, the magnetic response switch 10 is attached to the movable body 3 and moved. , a structure may be adopted in which the magnet 9 is fixed.

Effects of the present invention As described above, according to the present invention, the following effects can be obtained.

(a) a movable body that moves forward and backward depending on the presence or absence of a warm body to be tested, a temperature sensing element that detects the temperature of the hot body to be tested, and a coil spring that supports the movable body so that it can move back and forth;
It has a case that houses the movable body and coil spring, and a switch that is turned on and off by the forward and backward movement of the movable body, so it can detect the presence or absence of a hot body to be tested such as a cooker such as a rice cooker or a heating pan, and also measure its temperature. It is possible to provide a temperature detection device that can detect and control temperature, and that has a simple configuration and is easy to assemble.

(b) The movable body is made of either ceramic or heat-resistant resin, and is formed into a cylindrical shape with an upper surface that comes into contact with the hot body to be tested, a bottom surface that opposes this upper surface, and side surfaces. A metal plate with good conductivity is attached, and the temperature sensing element is in contact with the inner surface of the metal plate through the top surface of the movable body, and the coil spring is connected to the outer circumference of the side surface of the movable body and the inner circumference of the case. The movable body is supported in the space created between the movable body and the inner surface of the case, and due to the heat insulation effect of the space created between the movable body and the inner surface of the case, and the heat insulation effect of the movable body itself, the metal plate is heated through the movable body from the case to the metal plate. This suppresses heat conduction and reduces measurement errors in the temperature sensing element, which is thermally coupled to the metal plate, making it possible to detect the temperature of the object being tested with high accuracy.

(c) A metal plate with good thermal conductivity is attached to the top surface of the movable body that will be in contact with the hot body to be tested.
Since the temperature sensing element is thermally coupled to the inner surface of the metal plate, the temperature of the object being tested can be sensitively sensed.

(d) The switch is a combination of a magnet and a magnetically responsive switch, and the magnet and magnetically responsive switch operate based on the distance between the bottom surface of the movable body and the inner bottom surface of the case. and the inner bottom surface of the case, so that the magnetic field of the magnet acts on the magnetically responsive switch through a space that is stable in terms of the magnetic circuit. Therefore, a temperature detection device with stable switch operation can be provided.

(e) Since the switch is provided on the bottom of the movable body and on the inner bottom of the case on the side opposite to the side in contact with the hot body to be tested, the influence of the temperature on the hot body to be tested side is reduced, ensuring stable operation. In addition, the operation is made according to the distance between the bottom of the movable body on the side opposite to the side in contact with the hot body to be tested and the inner bottom of the case, so the operating distance is sufficiently short and a reliable switch can be achieved. Operation can be ensured.

(f) Since the switch is provided on the bottom of the movable body and the inner bottom of the case, the case protects the switch and prevents breakage and damage during use.

[Brief explanation of drawings]

Fig. 1 is a front partial sectional view of a temperature detection device according to the present invention realized for use in a cooking appliance such as a rice cooker, Fig. 2 is a front partial sectional view of the temperature detection device in the same state of use, and Figs. FIG. 2 is a diagram showing a lead wire connection mode between a temperature sensing element and a magnetically responsive switch of the temperature detection device according to the present invention. DESCRIPTION OF SYMBOLS 1... Case, 3... Movable body, 4... Spring, 6... Temperature body to be tested, 8... Temperature sensing element, 9... Magnet, 10... Magnetic response switch.

Claims (1)

[Scope of Claim for Utility Model Registration] A movable body that moves forward and backward depending on the presence or absence of a warm body to be tested, a temperature sensing element that detects the temperature of the warm body to be tested, a coil spring that supports the movable body so that it can move forward and backward, and the movable body and a case for storing the coil spring, and a switch that is turned on and off by forward and backward movement of the movable body, wherein the movable body is made of either ceramic or heat-resistant resin, and the temperature detection device It is formed into a cylindrical shape having an upper surface that is in contact with the temperature sensing element, and a bottom surface and side surfaces that face the upper surface, and a metal plate with good thermal conductivity is attached to the upper surface, and the temperature sensing element is The coil spring is in contact with the inner surface of the metal plate through the upper surface of the movable body, and the coil spring is located in a space created between the outer circumference of the side surface of the movable body and the inner circumference of the case. The switch is a combination of a magnet and a magnetically responsive switch, and the magnet and the magnetically responsive switch include:
corresponding to the bottom surface of the movable body and the inner bottom surface of the case so as to operate according to the distance between the bottom surface of the movable body and the inner bottom surface of the case that faces the bottom surface with a space therebetween. A temperature detection device characterized in that: