JPH01166719A - Jar rice-cooker - Google Patents

Abstract

PURPOSE: To make a valve of a steam port securely operate at a prescribed temperature by attaching the valve inside a steam port on the outer lid of a thermal rice cooker to be engaged with a tapered part of the steam port, and attaching a coil spring and a shape memory alloy coil to open/close the steam port by energizing the valve in opposite directions each other. CONSTITUTION: When water and rice are put in a pot 1 of this thermal rice cooker and electricity is turned on, a valve 12 is pressed on a tapered part 11a of a steam port 11 by the energizing force of a coil spring 13, and the steam port 11 is closed. When the pot 1 is heated by a heater 4 and the temperature inside the pot rises, a shape memory alloy coil 14, detecting the temperature, tries to restore its original length, and pushes up the valve 12 resisting the energizing force of the coil spring 13. Thus, a gap is formed between the valve 12 and the tapered part 11a of the steam port 11, and steam is let out from the gap. When cooking is finished and the temperature inside the pot drops to keep the rice warm, the energizing force of the shape memory alloy coil 14 becomes weak, and the valve 12 is pressed on the tapered part 11a of the steam port 11 again by the energizing force of the coil spring 13, thereby the gap is closed. By this way, the inside of the thermal rice cooker is sealed when the rice is kept warm.

Description

[Detailed description of the invention] Industrial applications This invention relates to a jar rice cooker.

2. Description of the Related Art Conventionally, as shown in FIG. 3, the steam vents of this type of jar rice cooker are such that the pressure of the steam generated when the water in the pot is heated pushes up a weight 22 provided in the steam vent 21, and the inside of the rice cooker is heated. It has a structure that allows steam to escape.

Problems to be Solved by the Invention However, with such a structure, the water temperature inside the pot is 10
Steam is generated when the temperature reaches 0°C or higher, and the steam vent 21 does not operate until the pressure of this steam increases to push the weight 22 and raise the pressure, which causes the inside of the rice cooker to become heated and cause boiling over. was there. Furthermore, if preliminary holes are provided to avoid this, heat and steam leak through the preliminary holes during warming, resulting in problems such as poor thermal efficiency and drying of the surface of the rice.

The present invention solves the above-mentioned problems, and aims to provide a rice cooker in which the steam vent can be reliably operated at a predetermined temperature.

Means for Solving the Problems In order to solve the above problems, the present invention provides a valve in a tapered steam hole that engages with the tapered portion of the steam hole,
A coil spring and a coiled shape memory alloy are provided to bias the valve in opposite directions to open and close the steam hole.

Effect With the above configuration, when the temperature inside the jar rice cooker is lower than the operating temperature of the coiled shape memory alloy, the valve is pressed against the tapered steam hole wall by the coil spring to close the steam hole, and the temperature inside the jar rice cooker decreases. When the temperature rises, the coiled shape memory alloy assumes the predetermined shape memorized at that temperature, pushing the coil spring back and moving the valve to open the steam vent. Further, when rice cooking is finished and the rice is kept warm, the temperature inside the pot decreases, so the biasing force of the coiled shape memory alloy becomes weaker and the steam holes are closed.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings.

FIG. 2 is a partially sectional front view of a jar rice cooker showing an embodiment of the present invention. In FIG. 2, reference numeral 1 denotes a pot housed in a rice cooker main body 2, which is placed on a heater 4 having a heat-sensitive device 3 in the center. Reference numerals 5 and 6 indicate heat-retaining heaters disposed inside the rice cooker main body 2 and the outer lid 7, respectively. Reference numeral 8 denotes an inner cover having a plurality of holes, and is attached to a shaft 9 protruding from the center of the outer cover 7.

The outer lid 7 has a hinge shaft 1 provided at the upper end of the rice cooker main body 2.
0, and is provided with a tapered steam hole 11 that communicates from the inside to the outside and spreads upward. This steam hole 11 is provided with a valve 12 that engages with its tapered portion 11a.

FIG. 1 is an enlarged sectional view of the steam hole 11. In FIG. 1, the diameter d of the valve 12 is larger than the small diameter D1 on the lower side of the steam hole and smaller than the large diameter D2 on the upper side of the steam hole. Further, a coil spring 13 is disposed between the upper surface of the valve 12 and the upper inner edge 11b of the steam hole 11,
A coiled shape memory alloy 14 that expands when a predetermined temperature is reached is disposed between the lower surface of the steam hole 11 and the lower inner edge 7a of the steam hole 11.
The coil spring 13 is stronger when the temperature is low or when the temperature is kept warm, and the valve 12 is pressed against the tapered portion 11a to close the steam hole 11. The steam hole 11 communicates with the outside and the inside of the rice cooker via an upper communication hole 15 and a lower communication hole 16.

In the above configuration, when water and rice are placed in the pot 1 and electricity is started, the valve 12 is pressed against the tapered portion 11a of the steam hole 11 by the biasing force of the coil spring 13, so that the steam hole 11 is closed. It is. When the pot 1 is heated by the heater 4, the water temperature rises, and the temperature inside the pot rises, the coiled shape memory alloy 14 senses the temperature and attempts to return to a predetermined length. As a result, the coiled shape memory alloy 14 resists the biasing force of the coil spring 13 and pushes up the valve 12 to the position shown by the chain line in FIG.
A gap is formed between the pipe and the tapered portion 11a, and steam is released from this gap. When rice cooking is finished and the temperature inside the pot decreases due to the heat retention state, the biasing force of the coiled shape memory alloy 14 weakens, and the valve 12 is again pressed against the tapered portion 11a of the steam hole 11 by the biasing force of the coil spring 13. , close the above gap. As a result, the inside of the jar rice cooker is sealed when keeping warm.

Effects of the Invention As described above, according to the present invention, the steam hole is opened and closed according to the temperature inside the pot using a coil spring and a coiled shape memory alloy that bias the valve provided in the steam hole from both sides. The steam vent can be reliably opened before the inside of the pot becomes overheated, allowing the steam inside the pot to escape and preventing boiling over. Since the steam holes are closed at low temperatures or when keeping warm, thermal efficiency is good and moisture on the surface of the plate does not escape, thereby preventing dry conditions during keeping warm.

[Brief explanation of the drawing]

Fig. 1 is an enlarged sectional view of the steam vent of a jar rice cooker showing an embodiment of the present invention, Fig. 2 is a front view showing a part of the same jar rice cooker in cross section, and Fig. 3 is a conventional It is an expanded sectional view of the steam hole part of a rice cooker. 2...Rice cooker main body, 7...Outer lid, 11...Steam hole, lla...Tapered part, 12...Valve, 13...Coil spring, 14...Coil shape memory alloy. Agent Yoshihiro Morimoto 1iif Figure 1f ft--Ichikunya-kyo ffa--Theno e-1-do f2--Ippen Figure 3

Claims (1)

[Claims] 1. A tapered steam hole that spreads upward is provided in the outer lid that closes the top opening of the rice cooker, and a valve that engages with the tapered portion is provided in this steam hole, and the valves are biased in opposite directions. A rice cooker equipped with a coiled spring and coiled shape memory alloy that opens and closes the steam vent.