JPH0743040B2 - Rubber bell seal Seal mechanism of bellows shaft seal of thermostat with straight tube structure - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a shaft-type bellows seal mechanism for a wax-type thermostat that controls the temperature of a coolant of an automobile engine.

The wax type thermostat opens the valve when the temperature of the engine coolant rises above the optimum temperature to lower the temperature, and closes the valve below the proper temperature to keep the engine coolant at the optimum temperature at all times. Opening and closing is fine sand, rust, scale,
Since it is always performed in oil and cooling liquid that becomes sludge-like with antifreeze liquid LLC, the shaft seal between the guide member and the push rod that slides relatively when the valve of the thermostat opens and closes governs the life of the thermostat. It is no exaggeration to say so.

Until now, the manufacturer's warranty for wax type thermostats for temperature control of automobile engines was 20,000 km per year, but only 5 at a time.
Today, it has been extended to 100,000 km per year, and today's conventional packing and O-
It seems that the sealing mechanism such as a ring is not sufficient.

The sealing mechanism of the present invention is a replacement for the bellows sealing mechanism without relying on the conventional packing and O-ring. Since the cooling liquid and foreign matter are completely prevented from entering the thermo-actuator, there is no overcooling or overheating of the engine due to the inclusion of liquid, as described later, and the thermal efficiency of the engine is improved and harmful waste gas is removed. Is less likely to occur, and engine trouble due to overheating is eliminated. Furthermore, since the lubricating oil in the sliding portion is retained for a long time by the bellows, the life of the thermostat is remarkably increased, and the merits of the bellows are extremely large.

However, the bellows are extremely expensive. The development of a low-cost manufacturing method for bellows is the most important issue.

It is an object of the present invention to expandably and hermetically connect a push rod of a thermo-actuator and a guide member to each other by a bellows so that the coolant and foreign matter can be completely prevented from entering the inside.

Another object of the present invention is to obtain a low-cost manufacturing method of bellows.

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 fully opened lift of the main valve and the latter showing the valve open. Generally, a wax-type thermostat is, as shown in FIG. 1, a frame 3 fixed to a housing 2 forming a valve seat 1, a main valve 4 engaging with the valve seat 1, and a guide member of a thermo-actuator 5 for press-fitting and fixing the main valve 4. 6 and a return spring 7 engaged between the main valve 4 and the frame 3.

The thermo-actuator 5 comprises a push rod 8, a guide member 6 engaging with the push rod 8 and an elastic seal spool 9, which are integrated with each other and inserted into a heat sensitive cylinder 11 filled with wax 10 to be pressure-bonded.

Reference numeral 12 is a bellows having a straight tube structure, and the tip of the push rod 8 of the thermo-actuator 5 is inside the apex 13 of the bellows 12, and the guide member 6 is a skirt portion 14 of the bellows 12 having a straight tube structure.
The main valve 4 is inserted into the guide member 6 together through the bellows 12 and the stop ring 15 guides
Secure to member 6.

When the temperature of the engine coolant rises, the elastic seal spool 9 is deformed by the melt expansion of the wax 10 in the heat sensitive cylinder 11, and the push rod 8 is squeezed upward. However, the push rod 8 is connected to the housing 2 via the bellows 12 having a straight tube structure.
Since it is engaged with and supported by the apex 16 of the main valve 4, the main valve 4 opens relatively downward (FIG. 1).

When the water temperature falls, the molten wax 10 in the heat-sensitive cylinder 11 solidifies and shrinks, so the return spring 7 causes the main valve 4 to move.
Closes (Fig. 2). In this way the top of the housing 2
The guide member 6 of the thermo-actuator 5 slides up and down with respect to the push rod 8 that is engaged and supported by 16, and the main valve 4 fixed thereto opens and closes correspondingly.

3 and 4 are cross-sectional views of a conventional wax-type thermostat, in which the elastic seal is applied by the lateral pressure exerted by the molten wax 10 from the closed state (FIG. 3) in which water has already entered the elastic seal spool 9. Since the spool 9 presses the push rod 8, the liquid reaches the fully open lift, which is contained in the tip of the push rod 8 (Fig. 4). A curve B (dotted line) in FIG. 5 shows a diagram of the temperature of the coolant versus the valve lift in this case. Curve A (solid line) is an elastic seal
It is a measured value in the case of the present invention (FIGS. 1 and 2) in which there is no liquid in the spool 9.

In the case of curve B, the valve opening temperature is low, and when the valve is closed, the valve does not close due to the interposition of liquid and opens slightly. It becomes over-cooled and the thermal efficiency of the engine is reduced, resulting in more generation of harmful waste gas. Also, due to the presence of this liquid, the lift rises excessively, the thermo actuator punctures, the wax leaks, the valve closes, and overheat is induced, resulting in a serious engine trouble.

In the present invention, the protection of the bellows and the complete invasion of liquid and foreign matter are prevented, so that the engine overcool and overheat are eliminated, and the life of the wax type thermostat is greatly extended.

FIG. 6 shows a single-cavity unit mold for manufacturing bellows, FIG. 7 is its female mold, and FIG. 8 is its male mold.

Male and female of this single-piece unit mold for forming the bellows are separated, and a large number of them are fixed to the upper and lower mold plates of the molding machine, respectively, and the raw materials are injected between the molds under high temperature and high pressure to mass produce them all at once. is there.

FIG. 9 shows a sectional view of the product.

Its apex 13 engages with the tip of the push rod 8, its skirt portion 14 engages with the guide member 6, and its body portion 17
Has a length that is slidable on the push rod 8 and that corresponds to the full-open lift of the main valve 4, and a body portion 17 thereof is provided with a plurality of ring-shaped ribs 18 corresponding to the number of bellows steps.

When this is attached to a thermostat, it is pressed by the return spring 7 and the inner portion of the thick ring-shaped rib portion remains the same, and the thin middle portion with relatively low resistance swells and a bellows is automatically formed very easily. Yes (Fig. 2). Moreover, since each valley of the bellows is protected and reinforced by the ribs, its expansion and contraction life is outstanding.

As described above, the bellows manufacturing method of the present invention is composed of the body portion including the apex portion and the skirt portion, and since the required number of ring-shaped ribs is provided on the body portion, the die is extremely easy to manufacture, and at the same time. Many can be molded and low cost bellows can be obtained.

This method of manufacturing the bellows can be used not only for the wax-type thermostat of the present invention but also for low-cost manufacturing of various bellows for empty, hydraulic cylinders and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a wax-type thermostat according to the present invention when fully opened, FIG. 2 is a sectional view when the valve is closed, and FIGS. 3 and 4 are sectional views of a conventional wax-type thermostat. The former shows when the valve is closed and the latter shows when it is fully opened. Fig. 5 shows the diagram of the valve opening temperature vs. valve lift, Fig. 6 shows the one-piece unit mold for bellows manufacturing, and Fig. 7 shows the female mold. The mold, FIG. 8 is the male mold, and FIG. 9 shows the sectional view of the product. 4 …… Main valve 5 …… Thermo actuator 6 …… Guide member 7 …… Return spring 8 …… Push rod 9 …… Elastic seal spool 10 …… Wax 11 …… Heat sensitive tube 12 …… Straight The bellows of the tube structure 13 ... the top of the bellows 14 ... the bellows skirt 15 ... the retaining ring 17 ... the body 18 ... the annular rib of the body

Claims (1)

[Claims] Claims: 1. The inner surface of the apex is fixed to the tip of the push rod (8), and the skirt portion (14) is fixed to a guide member (6) into which the push rod is slidably mounted, and its body portion. (17) is slidable on the push rod, and its length is determined according to the total stroke of the push rod so that it has a required annular rib (18) axially formed on the outer surface of the body. When the body is compressed by being pushed into the guide member by the push rod, each of the annular ribs (1
The push rod characterized in that the middle of 8) is configured to project outward from the push rod to form a bellows.
A bellows shaft sealing mechanism of a thermostat with a rubber seal straight tube structure for sealing the sliding part between the rod and the guide member.