JPH081346Y2 - Transmission breather structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an improvement in a breather of a transmission.

(Prior Art and its Problems) Conventionally, a breather of a transmission has a structure as shown in FIG.
A guide tube 52 is provided in a protruding shape on the 51, and a cover 53 is provided to cover the end of the guide tube 52.
A rubber sheet 55 is disposed inside 53 in a state of being urged downward via a spring 54, and the rubber sheet 55 is in contact with the upper end portion of the guide tube 52.

In such a structure, when the internal pressure in the transmission case increases, the rubber sheet 55 is pushed upward against the biasing force of the spring 54, and the internal pressure is designed to be equal to the external atmospheric pressure.

In such a conventional structure, the pressing force of the rubber sheet 55 is adjusted by the urging force of the spring 54, and if the urging force of the spring 54 varies, there is a problem that the breather performance is not sufficiently exhibited. ,spring
If there were quality variations in 54, there was an adverse effect such as oil leakage.

Further, due to deterioration of the rubber sheet 55, the rubber sheet 55 may be stuck to the upper end of the guide tube 52, and in such a case, the function as the breather is lost. It was

(Means for Solving the Problems) The present invention has been devised in view of the above-mentioned conventional problems, and an object thereof is not to provide a breather structure capable of exhibiting excellent breather performance, and the gist thereof is a transmission. In a breather that keeps the internal pressure and the external air pressure constant in a transmission case through a hollow pipe fixed to the case in a protruding manner, a horizontal portion is formed by bending the upper end of the hollow pipe horizontally, and an outer portion is formed at the end of the horizontal portion. Form an opening that opens to the outside air side that has a valve seat portion that has expanded to
A shape memory alloy plate that closes the opening is disposed substantially vertically in contact with the valve seat portion, and an upper end portion of a cap that covers the side surface and the upper surface side of the shape memory alloy plate is the shape memory. The temperature of the inside of the transmission case is fixed to the upper edge of the alloy plate and fixed to the upper edge of the valve seat through a screw so that only the lower edge of the shape memory alloy plate has a free end. The lower edge portion of the shape memory alloy plate is deformed by the upward movement to form a gap between the shape memory alloy plate and the valve seat portion.

(Function) A shape memory alloy plate is arranged on the open end side of the hollow pipe so that it can be opened and closed. The internal pressure in the transmission case rises as the temperature in the transmission rises. When the temperature rises, the shape memory alloy plate is deformed as the temperature rises, the opening of the hollow pipe is opened by the deformation, and the transmission case and the outside air can be communicated, and the internal pressure inside the transmission case is made equal to the outside atmospheric pressure. be able to. Also, in a normal state, when the internal pressure in the transmission is not high, the temperature does not rise, and the shape memory alloy plate satisfactorily closes the opening of the hollow pipe, preventing water and the like from entering the inside through the opening. Can be prevented.

Further, by bending the tip of the hollow pipe in the horizontal direction and disposing the shape memory alloy plate in a substantially vertical shape at the tip opening, the open / close operation of the shape memory alloy plate may be hindered by its own weight. Therefore, the opening / closing operation according to the set value can be performed satisfactorily.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a main part of the transmission case 1 in which the hollow pipe 2 is fixed to the mounting portion 1a in a protruding manner. The upper end of the hollow pipe 2 is a horizontal portion 2a that is bent horizontally. The tip of the horizontal portion 2a is an opening K that opens to the outside air side. This opening K side is the second
As shown in the enlarged view of the drawing, a valve seat portion 2b is formed which is expanded outward, and the shape memory alloy plate 4 is attached to the valve seat portion 2b so as to abut. The shape memory alloy plate 4 normally closes the opening K.

The shape memory alloy plate 4 has a side surface and an upper surface side covered with a cap 3 provided on the outside, and an upper end portion of the cap 3 is attached to an upper end portion of the valve seat portion 2b via a screw 5, The upper edge of the memory alloy plate 4 is integrally fixed by screws 5. Therefore, the shape memory alloy plate 4 can be opened and closed only at its lower edge as a free end.

The shape memory alloy plate 4 is made of, for example, a nickel-titanium alloy, has excellent corrosion resistance and durability, and has a strong shape recovery force. The shape memory alloy plate 4 deforms when reaching a predetermined temperature, and the valve seat portion
The opening S can be opened by forming a gap S with the 2b.

In the present example, the shape memory alloy plate 4 is arranged in a substantially vertical shape, and the shape memory alloy plate 4 is deformed by the temperature change satisfactorily according to the set value without the weight of the shape memory alloy plate 4 acting to form the gap S. It is arranged so that it can.

Now, when the internal pressure in the transmission case 1 rises as the internal temperature rises, the elevated temperature is transmitted through the hollow pipe 2 and acts on the shape memory alloy plate 4, the shape memory alloy plate 4 begins to deform, and the valve seat portion. A gap S is formed between it and 2b. Due to this gap S, the inside of the transmission case 1 and the outside air are in communication with each other, and the outside air and the internal pressure are kept constant. When the temperature inside the transmission case 1 does not rise, the internal pressure also does not rise, so the shape memory alloy plate 4 is in close contact with the valve seat portion 2b and closes the opening K. Especially, when water or the like tries to enter the shape memory alloy plate 4 from the outside, the temperature of the shape memory alloy plate 4 is lowered by the water or the like, so that the opening K is closed more firmly and the water or the like enters the transmission case 1. Can be well prevented.

The shape memory alloy plate 4 may be made of copper alloy or other durable material.

(Effect of the Invention) The present invention relates to a breather that keeps the internal pressure and the external pressure of the transmission case constant through a hollow pipe fixed to the transmission case in a protruding manner. An opening that is open to the outside air and that has a valve seat portion that expands outwardly is formed at the tip of the horizontal portion, and a shape memory alloy plate that closes the opening is abutted against the valve seat portion. The upper edge of the cap, which is arranged substantially vertically and covers the side surface and the upper surface of the shape memory alloy plate, is integrated with the upper edge of the shape memory alloy plate through a screw, and the upper edge of the valve seat portion is formed. The shape memory alloy plate is fixed to the front end of the shape memory alloy plate so that only the lower edge of the shape memory alloy plate has a free end. By forming a gap between the valve seat and the valve seat, when the temperature inside the transmission rises and the internal pressure of the transmission rises, the lower edge of the shape memory alloy plate deforms as the temperature rises, and the opening Is opened to communicate with the outside air, the internal pressure in the transmission communicates with the outside air pressure, and the internal pressure is maintained at a constant value. Further, when there is no increase in the internal pressure, the shape memory alloy plate closes the opening of the hollow pipe, and water or the like can be effectively prevented from entering the inside.

In particular, the shape-memory alloy plate is affected by its own weight by bending the opening end side of the hollow pipe in the horizontal direction and disposing the shape-memory alloy plate in a substantially vertical shape in the opening of the hollow pipe. Since it does not exist, it is deformed according to the set value, and further protected by the cap, which has the effect of being able to perform a favorable opening / closing operation.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a sectional view showing the main part of the transmission case in which a hollow pipe is connected, FIG. 2 is an enlarged sectional view showing the end of the hollow pipe, and FIG. It is a cross-sectional block diagram of the conventional breather structure. 1 …… Transmission case 2 …… Hollow pipe 2a …… Horizontal part 2b …… Valve seat part 3 …… Cap 4 …… Shape memory alloy plate 5 …… Screw K …… Opening S …… Gap

Claims (1)

[Scope of utility model registration request] 1. A breather for maintaining a constant internal pressure and an external atmospheric pressure of a transmission case through a hollow pipe fixed to a transmission case so as to form a horizontal portion by bending an upper end portion of the hollow pipe horizontally. An opening is formed at the tip of the horizontal portion and has an outwardly open valve seat portion that opens to the outside air side, and a shape memory alloy plate that closes the opening is arranged substantially vertically in contact with the valve seat portion. The shape memory alloy plate is provided with an upper end portion of a cap that covers the side surface and the upper surface side of the shape memory alloy plate integrally with the upper edge portion of the shape memory alloy plate and fixed to the upper edge portion of the valve seat portion via a screw. Only the lower edge of the shape memory alloy plate is a free end, and the lower edge of the shape memory alloy plate is deformed by the temperature rise in the transmission case, thereby forming a free end. Breather structure of the transmission, characterized by being configured so as to form a gap.