JPH04321712A - Thermostat - Google Patents

Abstract

PURPOSE:To surely discharge air in the circulating course of cooling water at exchanging cooling water by giving an elastic member with which a valve is energizated in the opening direction by smaller energizating force than the pressure of cooling water applied on the valve at operating an engine. CONSTITUTION:In an air bleed jiggle valve 30 of a thermostat to modulate the temperature of cooling water in an engine, a spring 35 to energizate the jiggle valve in the opening direction by smaller energizating force than the pressure of cooling water applied on the jiggle valve at operating an engine is given. Hereby, when the engine is stopped and the pump is stopped, the water pressure of cooling water applied on the valve part 33 is lowered to zero, and the jiggle valve 30 is opened by the energizating force of the spring 35. Accordingly, air in the circulating course of cooling water is surely discharged at exchanging cooling water.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermostat for regulating the temperature of cooling water inside an engine.

0002

2. Description of the Related Art As shown in FIG. 3, a conventional cooling device for cooling an engine 1 mainly includes a radiator 6, a pump 2, a water jacket 4, a thermostat 3, and a cooling fan 8. Among these, the role of the thermostat 3 is to select the circulation path of the cooling water in accordance with the water temperature. The thermostat 3 is generally located at the top of the engine, near the engine joint of a pipe 7 that sends high-temperature cooling water through the water jacket 4 to the radiator 6. FIG. 4 shows an example of a wax type thermostat among conventional thermostats. When the cooling water is low temperature, the valve part 1 of the thermostat 3
1 is closed and cooling water flows only through the short circuit path 5 to the pump 2. When the engine 1 is started and the temperature of the cooling water rises after a while, the valve part 11 is opened, and most of the cooling water flows to the radiator 6 and takes a circulation path to be cooled.

When replacing the coolant after the engine has stopped, first open the drain cock 10 at the bottom of the radiator to drain the coolant. At this time, the air that entered the radiator 6,
Satisfies water jacket 4 etc. Next, close the drain cock 10 and inject new cooling water from the radiator cap 9. The cooling water will flow through the cooling water circulation path in the order of radiator 6, pipe 7, or radiator 6, pump 2, and water jacket 4. However, since the valve part 11 of the thermostat 3 is closed at this time, the air remaining in the upper part of the water jacket does not escape and remains. If air remains in the cooling water circulation path, problems such as overheating and engine seizure are likely to occur.
A jiggle valve 20 for air venting was adopted in the . As shown in FIGS. 5 and 6, this jiggle valve 20 includes a head 21, a shaft 22, a valve part 23, and a flange side opening 2.
It has a structure consisting of 4 parts, and when the engine is stopped or the cooling water is drained, it is opened due to its own weight, but pump 2
When activated, the pressure of the cooling water passing through the valve 20 is
It joins the valve part 23 and closes it (dotted chain line C).

0004

Problems to be Solved by the Invention In some cases, the thermostat 3 must be installed at an angle or directly to the side, as shown in FIG. 7, depending on the space inside the engine. Even in such a case, the jiggle valve 20 may be opened as shown in FIG. 8 when the engine is stopped. However, since the jiggle valve 20 is designed to be opened by the weight of the valve part 23, when the valve part 23 tries to fall vertically, the shaft part 22 comes into contact with the opening part 24 and becomes locked as shown in FIG. , the valve may not open sufficiently. In such a case, if new coolant is rapidly injected, the amount of air that can pass through the valve will be less than planned, resulting in air remaining in the upper part of the engine in the coolant circulation path, impairing the cooling effect of the engine, and causing damage to the engine. becomes more likely to be damaged.

[0005]

[Means for Solving the Problems] As a means for solving the above problems, the first invention provides an elastic member that applies a biasing force in the opening direction that is weaker than the water pressure of the cooling water acting on the valve portion of the valve during engine operation. is given to the jiggle valve. Also,
In the second aspect of the invention, a bimetallic member is provided to the jiggle valve, which applies a biasing force in the opening direction when the cooling water is low.

[0006]

In the first invention, when the engine is running and the pump is in operation, the water pressure of the cooling water applied to the jiggle valve overcomes the biasing force of the elastic member applied to the valve, and the jiggle valve is closed. When the engine stops and the pump stops, the water pressure of the cooling water applied to the valve portion becomes zero, and the jiggle valve is opened by the urging force of the elastic member applied to the valve.

In the second aspect of the invention, the bimetal member does not act on the jiggle valve while the engine is operating and the coolant is kept at a high temperature, so the jiggle valve is closed only by the water pressure of the coolant. When the engine is stopped, the water pressure of the cooling water becomes zero, and the temperature drops, the bimetallic member acts to bias the valve in the opening direction, so the jiggle valve is opened.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples embodying the present invention will be described below with reference to the drawings. (Example 1) Example 1 which embodies the first invention is shown in FIG. Since the engine and thermostat main bodies are the same as those of the prior art, their explanation will be omitted and the same reference numerals will be used. Similar to the prior art, the main body of the jiggle valve 30 includes a head 31, a shaft 32, and a valve portion 33. This jiggle valve 30 is attached to an opening 34 having an edge that guides the direction of expansion and contraction of a spring 35, and the spring 35 is fixed to the base of the edge of the opening 34 and the jiggle valve valve portion 33. The back edge of the valve part of the jiggle valve 30 has a shape that makes it easy to attach the spring 35, and the front side of the valve part 33 that receives the water pressure of the cooling water has a wider area so that it can receive water pressure more easily than conventional ones. There is. The jiggle valve 30 is connected to the flange portion 17 of the thermostat 3 in FIG. 4 or the valve portion 11.
It is located in

When the engine starts, the pump operates and the water pressure of the cooling water applied to the jiggle valve valve portion 33 increases.The water pressure gradually overcomes the biasing force of the spring 35 and the valve 3
0 is closed (dashed line A). When the pump 2 stops operating due to the engine 1 stopping, the pressure applied to the valve part 33 decreases and the urging force of the spring 35 causes the valve 3 to stop operating.
0 is free.

In this first embodiment, a spring is used as the elastic member and a valve portion is used as the attachment position of the elastic member, but it is also possible to use another material such as rubber as the elastic member, and the attachment position of the elastic member can be changed. can also be the shaft or head of the jiggle valve. (Example 2) Example 2 which embodies the second invention is shown in FIG. In the second embodiment, a bimetallic spring 45 is used in place of the spring 35 of the first embodiment. Other structures are the same as in the first embodiment, so the same parts are denoted by the same reference numerals. This bimetallic spring 45 is set to expand and contract at a temperature of about 50° C. and to contract at a high temperature. When the engine 1 is stopped and cold, the spring 45 expands, exerting a strong biasing force on the jiggle valve valve portion 33, and the valve 30 is opened. As soon as the engine 1 starts and the water temperature starts to rise, the spring 45
is reduced, the biasing force acting on the valve portion 33 is weakened, and the valve 30 can be easily closed by water pressure. Alternatively, the mouth portion 34
, and the biasing force acting on the valve portion 33 becomes zero (dotted chain line B).

Although there is some degree of discretion in setting the temperature as a reference for the expansion and contraction of the spring 45,
Basically, the cooling water does not flow to the radiator 6 until it warms up, so the spring 45 is set to contract as soon as possible after the engine starts.

0012

Effects of the Invention As detailed above, in the first invention, since the jiggle valve is sufficiently opened when the engine is stopped,
Air in the cooling water circulation path is reliably discharged when replacing the cooling water, and the engine will not be damaged due to residual air as in the prior art. Further, in the second aspect of the invention, the valve is sufficiently opened during cooling water exchange, and the bimetallic member does not act on the valve while the engine is running. Therefore, the valve opens and closes in the same manner as in the prior art, and the jiggle valve body can be used as is. In the first invention and the second invention, the jiggle valve itself is integrated with the thermostat as in the prior art,
It also has the advantage of easy maintenance.

[Brief explanation of drawings]

[Fig. 1] A sectional view showing the operation of a spring-equipped jiggle valve corresponding to Example 1.

[Fig. 2] Cross-sectional view of a bimetallic spring-equipped jiggle valve corresponding to Example 2

[Figure 3] Schematic diagram of engine cooling system

[Fig. 4] Cross-sectional view showing an example of a thermostat as a conventional technology

FIG. 5 is a sectional view showing the operation of a conventional jiggle valve.

[
Figure 6: Upper external view of the jiggle valve

[Fig. 7] Schematic cross-sectional view showing a thermostat arranged at an angle.

FIG. 8 is a cross-sectional view showing the operation of a prior art jiggle valve with an inclined thermostat;

[Fig. 9] Cross-sectional view showing the jiggle valve locked at the opening.

[Explanation of symbols]

3 Thermostat 9 Radiator cap 10 Drain cock 15 Wax case 17 Flange part 20 Jiggle valve 23 Jiggle valve valve part 30 Jiggle valve with spring 35 Spring 45 Bimetal spring

Claims (2)

[Claims] 1. In a jiggle valve for venting air from a thermostat that adjusts the temperature of cooling water inside the engine, an elastic member biases the valve in the opening direction with a biasing force weaker than the pressure of the cooling water applied to the valve during engine operation. Jiggle valve with . 2. A jiggle valve for venting air from a thermostat that adjusts the temperature of coolant inside an engine, the jiggle valve having a bimetallic member that biases the valve in the opening direction when the coolant is low.