JPH0329660Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention is equipped with a cover provided around the temperature sensing part in order to prevent the temperature sensing part from being adversely affected by the temperature of the external atmosphere. Regarding thermo valves.

(Prior Art) In general, a thermovalve has a valve body inserted into a cylindrical valve body, as disclosed in Japanese Patent Application Laid-open No. 54-45427 or Utility Model Application No. 60-42350 (Honda's earlier application), and the valve body is based on the valve body. A temperature sensing part is fixed to the end side, and when the temperature sensing part reaches a predetermined temperature, the wax sealed inside expands and drives the valve body.

(Problem to be solved by the invention) However, in conventional thermo valves, the temperature sensing part was covered airtight with a cover, so for example, a thermo valve fixed to a carburetor in the engine room In valves, as the temperature inside the engine room becomes extremely high, the temperature difference between the inside and outside of the cover increases, causing condensation on the surface of the temperature sensing part inside the cover, and dew droplets inside the cover. There is a problem that occurs. Furthermore, since the cover has a sealed structure, there is a risk that the wax inside the temperature sensing section will be compressed by the air expanded within the cover.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a thermovalve that can block the adverse effects of the external atmosphere, prevent dew condensation within the cover, and prevent the adverse effects associated with air expansion within the cover.

(Means for solving problems and their effects) In the thermovalve of the present invention, a valve body is inserted into a cylindrical valve body so as to be able to reciprocate, and a temperature sensing part that drives the valve body is fixed to the base end of the valve body. A cover is provided to cover the temperature sensing part. Further, a hole is formed at the bottom of the cover, and the inside of the cover is ventilated through this hole. Therefore, the temperature-sensing part is not exposed to the external atmosphere by the cover, so it is not affected by the negative effects of the external atmosphere, and since the inside of the cover is ventilated through the hole, there is no possibility of condensation forming or air expansion inside the cover. It is possible to prevent the negative effects associated with

(Example) An example of the present invention will be described below based on the accompanying drawings. In this embodiment, a thermovalve installed in a passage for guiding fuel evaporative gas in a float chamber of a carburetor to a canister will be explained as an example.

The thermovalve of this example is shown in FIG. 1st
In the figure, 1 is a carburetor, 2 and 3 are ventilation pipes and their intake passages, 4 is a bench area, 5 is a throttle valve, 6 is an air vent, and 7 is a float chamber. As shown in the figure, the float chamber 7 communicates with the air vent passage 6a through the communication hole 8.
A flange 9a provided at the tip side of a valve case 9 is thermally connected to the opening of the air vent passage 6a, and the valve case 9 is, for example, tilted slightly and floated with bolts 10 as shown in FIG. It is fixed to the outdoor wall 7a. A pipe 11 is connected to the base end side of the valve case 9, and the float chamber outer wall 7a, the valve case 9, and the pipe 11 constitute a passage 12 for guiding fuel evaporative gas from the float chamber 7 of the carburetor 1 to the canister (not shown). ing. In addition, as shown in FIG.
are being installed sequentially.

When the engine is running, the control valve 13 moves through the passage 12 as its valve body 14 moves against the urging force of a spring 16 interposed in the diaphragm chamber 15 due to the intake pressure from the air vent 6.
On the other hand, when the engine is stopped, the passage 12 is opened by the biasing force of the spring 16.

The thermovalve 18 includes a valve body 19 mounted in the valve case 9 with the tip side facing upstream, a valve body 20 inserted into the valve body 19 so as to be able to reciprocate, and a valve body 20 that biases the valve body 19. It includes a spring 21 and a temperature sensing part 22 that is attached to the base end side of the valve body 19 and drives the valve body 20. In addition, as shown in Fig. 3, the valve body 1
9 has a suction port 23 on its distal side and a discharge port 2 communicating with the pipe 11 on its proximal side.
4 is formed, and a seat portion 19a on which the valve body 20 is seated is formed inside. The temperature sensing portion 22 includes a cylinder portion 25 formed on the proximal end side of the valve body 19, a piston 26 inserted into the cylinder portion 25 and connected to a valve body 20 at its tip, and the cylinder portion 2.
A wax 29 and a semi-fluid 30 are sealed in a chamber defined by the piston 26, the cylinder portion 25, and the plug 27 via a diaphragm 28. . Therefore, heat is transferred from the carburetor 1 to the temperature sensing portion 22 via the float chamber outer wall 7a, the flange 9a, the valve case 9, and the valve body 19 of the carburetor 1. When the carburetor 1 reaches the set temperature, the semi-fluid body 30 of the temperature sensing part 22 melts and the wax 29 expands, causing the piston 26 to move in the axial direction and the valve body 20 to resist the biasing force of the spring 21. and lift. Therefore,
When the set temperature is reached when the engine is stopped, evaporated fuel gas is guided from the float chamber 7 to the canister and adsorbed therein.

In addition, a temperature sensing section 22 is provided on the base end side of the valve case 9.
A cover 31 covering the periphery of the temperature sensing section 22 is fixed by screws 32, and the temperature sensing section 22 is isolated from the outside atmosphere by the cover 32, so that the temperature sensing section 22 is not affected by the ambient temperature. Therefore, the temperature sensing section 22 can be operated accurately in accordance with the carburetor temperature, and will not be adversely affected by the high temperature trapped in the engine room when the engine is stopped after driving. . moreover,
A ventilation hole 31a is formed in the cover 31, as shown in FIGS. 3 and 4. this hole 3
1a is formed at the lowest position on the bottom of the cover because the bottom of the cover is inclined along with the valve body 19 and the valve case 9 which are installed in an inclined state. Therefore, the inside of the cover 31 is ventilated through the hole 31a.
Even if a large temperature difference occurs between the inside of the cover 31 and the atmosphere, dew condensation does not occur inside the cover 31. At the same time, the temperature sensing section 22 is not pressed due to the expansion of the air inside the cover 31. For example, even if dew condensation occurs inside the cover 31, since the hole 31a is provided at the lowest part, dew drops will not accumulate inside the cover 31. Furthermore, the cover 31 can protect the temperature sensing section.

(Effects of the invention) As is clear from the above explanation, according to the invention, a ventilation hole is provided at the bottom of the cover that covers the temperature-sensing section, so the temperature-sensing section is not affected by the external atmosphere. In addition to ensuring accurate operation of the temperature sensing part,
It is possible to prevent dew condensation inside the cover, and avoid the effects caused by the expansion of air inside the cover.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the present invention. Figure 1 is a vertical sectional view showing a thermo valve installed in a fuel evaporative gas passage together with a carburetor, and Figure 2 shows the mounting structure of the thermo valve. Fig. 3 is an enlarged cross-sectional view of the thermovalve;
The figure is a view taken along arrow N in FIG. 3 showing the cover. In the drawings, 18...Thermo valve, 19... Valve body, 20... Valve body, 22... Temperature sensing part, 2
3, 24... Suction and discharge ports, 31... Cover, 31a... Hole.

Claims (1)

[Scope of utility model registration request] A cylindrical valve body having a suction port on the distal end side and a discharge port on the proximal end side, a valve body inserted into the valve body so as to be able to reciprocate, and a valve body fixed to the proximal end side of the valve body to drive the valve body. What is claimed is: 1. A thermovalve equipped with a temperature-sensing section, characterized in that the temperature-sensing section is covered with a cover and a ventilation hole is provided at the bottom of the cover.