JPH03181678A - Bellows shaft sealing mechanism of thermostat of rubber-seal straight tube composition - Google Patents

Abstract

PURPOSE:To block invasion of a cooling liquid and foreign matters by providing a straight tube in which the head is held between the top of a housing and the tip of a push rod, the skirt is fixed to the end surface of a guide member, and the body is made slidable to a push rod, and recessed line grooves are formed on the inner surface. CONSTITUTION:In a rubber-seal straight tube 1, its head 2 is held between the top 5 of a housing 4 and the tip of a push rod 6, and its skirt 8 is fixed to the end surface of a guide member 9. And its body 7 can slide to the push rod 6, and a necessary number of recessed line grooves are formed at its inner surface. In such a composition, the rubber-seal straight tube 1 is guided by the push rod 6, and moves rearward when a return spring 17 pushes, being developed freely to form a bellows, and the sliding part between the push rod 6 of a thermostat and the guide member 9 is covered airtight by the flexible bellows. As a result, invasion of a cooling liquid and foreign matters to the inside can be blocked perfectly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a thermostat bellows shaft sealing mechanism comprising a rubber seal straight tube that is compressed and automatically becomes bellows when set in a target actuator.

The rubber seal straight tube for bellows of the present invention has its apex engaged with the tip of the push rod, its skirt engaged with a guide member on which the push rod is slidably attached, and its body engaged with the guide member on which the push rod is slidably attached. It is constructed as a straight tube which is slidably engaged with the push rod and whose length is determined to correspond to the entire stroke of the push rod.

When this straight tube is set in the target actuator, it will be compressed, and the body with no escape will automatically form a bellows. Thereafter, it repeats expansion and contraction as a bellows in response to the stroke of the push rod.

In this case, as long as the inner diameter of the body part is slidable on the push rod, and its length, wall thickness and hardness are the same, compressing it will automatically create a bellows with the same outer diameter and the same number of steps. is formed. However, in this case, it is inevitable that the shape will be somewhat irregular.

Therefore, a required number of concave grooves or convex ribs are provided on the body portion to correctly guide bellows formation.

A required number of concave grooves are provided on the inner peripheral surface of the body, and when these grooves are set in an actuator, they are compressed and each concave groove first swells to automatically form a bellows correctly.

Furthermore, even if a required number of convex ribs are provided on the inner peripheral surface of the body and these are set in an actuator, the body will be compressed and the thick central part between each of the convex ribs will swell first and automatically become bellows. It is formed.

Furthermore, the same result can also be obtained by providing a required number of convex ribs on the outer peripheral surface of the body.

Since the present invention does not make the bellows itself, but instead makes a rubber-sealed straight tube that becomes the bellows, it is extremely easy to make molds, and a large number of molds are installed in a molding machine, and the molds are molded under high temperature and high pressure. By clamping the mold and injecting the raw material into the mold, a large number of molds can be formed at once, resulting in extremely low-cost rubber-sealed straight tubes.

It is difficult to manufacture ultra-small bellows using the conventional method of creating the exact shape of the bellows from the beginning, and even if it were possible, it would be too expensive to be used.

The purpose of the present invention is to cover the sliding part between the push rod and the guide member of a thermo-actuator airtightly with a bellows so that it can be expanded and contracted to completely prevent cooling fluid and foreign matter from entering the inside. be.

Another object of the present invention is to provide a method of manufacturing a bellows at low cost.

Examples of the present invention will be described below.

1 and 2 are cross-sectional views of the wax type thermostat of the present invention, the former showing the main valve when it is fully open and the latter showing the main valve when it is closed.

In general, a wax type thermostat includes a frame 3 fixed to a housing 2 forming a valve M1, a main valve 4 engaged with a valve seat 1, and a thermostat to which the main valve 4 is press-fitted and fixed, as shown in Fig. 1.
It consists of a guide member 6 of the actuator 5 and a return spring 7 that engages between the main valve 4 and the frame 3.

The thermoactuator 5 includes a bushing rod 8, a guide member 6 engaged therewith, and a resilient seal spool 9.
are assembled into one body and inserted and pressed into a heat-sensitive tube 11 filled with wax 10.

The tip of the bushing/rad 8 of the thermo-actuator 5 is inserted inside the apex 13 of the bellows 12 and the skirt portion 15 of the bellows 12 is crimped into the seal pocket 14 formed on the end face of the guide member 6. The main valve 4 is press-fitted into the guide member 6 and fixed with a retaining ring 16.

When the temperature of the engine coolant rises, the elastic seal spool 9 is deformed by the melting and expansion of the wax IO in the thermosensitive cylinder 11, and the push rod 8 is squeezed out. However, push
Since the rod 8 is engaged with and supported by the apex I7 of the housing 2 through the bellows 12, the main valve 4 opens relatively and reaches a full open lift at a specified temperature (FIG. 1).

Also, when the liquid temperature starts to fall, the molten wax l inside the thermosensitive tube 11
Since O solidifies and contracts, the lift of the main valve 4 is reduced by the return spring 7, and when the specified temperature is reached, the main valve 4 is fully closed (FIG. 2).

In this way, the guide member 6 of the thermoactuator 5 slides up and down with respect to the push rod 8 which is engaged and supported by the apex 17 of the housing 2, and the main valve 4 fixed thereto corresponds to this. to open and close.

This valve is constantly opened and closed in coolant that becomes sludge-like due to fine casting sand, rust, scale, oil, and antifreeze, so when the thermostat valve opens and closes, the guide member 6 and push It is no exaggeration to say that the shaft seal between the rod 8 and the rod 8 governs the life of the thermostat.

Until now, the manufacturer's warranty for wax type thermostats is 1 year and 2 years.
Nowadays, what used to be 10,000 km has been extended to 100,000 km in 5 years, and it is impossible to cope with the conventional shaft sealing mechanism using backing and O-rings, and the only solution for the time being is to use bellows. It is.

Since the present invention does not produce the bellows itself, but instead produces a rubber-sealed straight tube that becomes the bellows, the cost is extremely low.

If this is adopted for the shaft seal of a wax-type thermostat, coolant and foreign matter will not enter the thermo-actuator 5, so the engine will not overcool or overheat due to the presence of liquid, and the thermal efficiency of the engine will be improved. As the engine temperature rises, the generation of harmful exhaust emissions decreases, and engine troubles caused by overheating also disappear.

Furthermore, overcooling due to sticking between the bushing rod 8 and the guide member 6 due to the intrusion of liquid and foreign matter is eliminated. Furthermore, the lubricating oil injected between the push rod 8, the sliding guide member 6, and the elastic seal spool 9 is not consumed due to the bellows 12, so the life of the thermostat is significantly increased. Extremely large.

3, 4, 5, and 6 each show a cross-sectional view of a rubber-sealed straight tube. The outer side of the tip of each straight tube is engaged with the apex I7 of the housing 2, and the inner side is engaged with the tip of the push rod 8, respectively, and the skirt portion 15 of the straight tube is engaged with the tip of the guide member 6 as shown in FIG. It is inserted into the seal pocket 14 formed on the end face, and the seal pocket part 1 is inserted as shown in FIG.
Press the outer side 18 of 4 to the inner side with hydraulic pressure and attach the rubber.
The sealing straight tube is firmly fixed to the guide member 6.

Figure 3 shows the basic rubber seal straight pipe.

FIG. 4 shows a case in which a plurality of concave grooves 20 are formed on the inner surface of the body section 19, FIG. A plurality of convex ribs 21 are formed on the outer surface.

In either case, when the push rod 8 is inserted and the apex 13 of the straight tube is pressurized, it automatically becomes bellows (Fig. 9).

The convex rib 22 is provided in any case to protect the head 23 of the bellows.

Figure 1O is an example of a rubber seal straight pipe mold.
The single-cavity mold unit for the straight tube shown in the figure is shown. 24 is the female mold, 25 is the male mold, and 26 is the raw material injection port.

The rubber straight tube for bellows with a diameter of 4° or more described above can be used not only for wax-type thermostats, but also for the low-cost manufacturing of various bellows for empty and hydraulic cylinders.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views of a wax-type thermostat equipped with the bellows of the present invention, and the former shows when the main valve is fully opened and lifted;
The latter shows the state when the valve is closed; Figures 3, 4, 5, and 6 are cross-sectional views of the rubber-sealed straight pipe, and Figures 7 and 8 are the rubber-sealed straight pipes. The process of inserting and crimping the skirt part into the guide member, FIG. 9 shows the state in which the rubber-sealed straight tube changes into a bellows, and FIG. 10 shows the mold uni-soto. 1,... Main valve 2,... Housing 4,... Main valve 5,... Thermo-actuator 6,... Guide member 7,... Return spring 86... 9, ... 0, ... 1, ... 2, ... 4, ... 5, ... 9 ... 20 ... 21 ... Push rod, elastic seal, spool wax thermosensitive tube Bellows seal/pocket skirt body part concave groove convex rib

Claims (1)

[Claims] 1. When attached to a thermostat, the inner surface of the tip of the rubber seal straight tube, which automatically contracts and becomes bellows, is engaged with the tip of the push rod of the thermoactuator, A shaft sealing mechanism for a thermostat, characterized in that a skirt portion of a tube is inserted and crimped into a seal pocket formed on an end face of a guide member in which a push rod is slidably engaged. 2. Its apex engages with the tip of the push rod, its skirt engages with a guide member on which the push rod is slidably attached, and its body is slidable on the push rod and its length A rubber seal bellows characterized in that the length is configured as a straight tube whose length corresponds to the entire stroke of the push rod. 3. Its apex engages with the tip of the push rod, its skirt engages with a guide member on which the push rod is slidably attached, and its body is slidable on the push rod and its length The rubber seal bellows is characterized in that the rubber seal bellows is configured as a straight tube having a length determined corresponding to the entire stroke of the push rod and a required number of grooves formed on the inner circumferential surface of its body. 4. Its apex engages with the tip of the push rod, its skirt engages with a guide member on which the push rod is slidably attached, and its body is slidable on the push rod and its length A rubber seal bellows characterized by being configured as a straight tube with a length determined corresponding to the entire stroke of a push rod and a required number of convex ribs formed on the inner circumferential surface of its body. 5. Its apex engages with the tip of the push rod, its skirt engages with a guide member on which the push rod is slidably mounted, and its body engages with the push rod so that it can slide freely and its length A rubber seal bellows, characterized in that the rubber seal bellows is configured as a straight tube with a length determined corresponding to the entire stroke of the push rod, and a required number of convex ribs formed on the outer peripheral surface of its body.