JPH0583826B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a He expansion engine for a vehicle-mounted refrigerator, and particularly to an expansion engine with an improved valve opening/closing mechanism.

[Prior art and its problems]

Conventional He expansion engines have an exhaust valve that opens and closes the exhaust port on the side of the cylinder when a valve seal attached to a sliding member that is driven by the reciprocating motion of the piston slides along the inner wall of the cylinder. I have it.

FIG. 1 shows the structure of an exhaust valve for a He expansion engine according to the prior art. When the piston 1 in the figure is pushed up by the pressure of He gas taken in from the intake valve 2, the sliding material 3 is pulled up just before the piston reaches the bottom dead center, and the valve seal 4 fixed to the sliding material
Since the He gas leaves the exhaust port 5, the inhaled He gas is exhausted. Furthermore, even when the piston 1 begins to descend, the sliding member 3 remains in the same position due to the frictional resistance between the cylinder and the valve seal, and is pushed down just before the piston reaches top dead center, and the valve seal blocks the exhaust port. One cycle ends.

However, in automatic exhaust valves having such a structure, the sliding surface of the valve seal wears rapidly, making it impossible to maintain the initial performance of the engine for a long period of time, and improvements in this respect are desired.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to significantly improve the durability of the exhaust valve by making the valve sealing surface of the exhaust valve non-sliding.

[Summary of the invention]

The expansion engine of the present invention includes a cylinder for adiabatically expanding sucked gas, a piston provided in the cylinder so as to be able to reciprocate, and an exhaust port provided near the bottom of the cylinder for discharging the gas. and provided in the cylinder, for engaging with the piston at predetermined positions before the piston reaches top dead center and bottom dead center, respectively, and moving in the movement direction of the piston to open and close the exhaust port. a sealing device having one end fixed to the cylinder and moving to engage with the piston from the predetermined position before the piston reaches top dead center, and the other end engaging the sealing device; applying a force in the direction of closing the exhaust port to the piston until the piston engages with the seal device again at the predetermined position before the piston reaches bottom dead center and separates the seal device from the exhaust port; and an elastic member that continues to engage with the sealing device and continue to apply a force in the direction of closing the exhaust port.

The outline of the present invention will be explained in more detail below with reference to FIG. (referred to as sliding material)
and a valve seal fixed to this sliding member, and the elastic member is a leaf spring.
Furthermore, the engagement timing between the sealing device and the piston is determined by a timing mechanism consisting of a groove and a pin formed in the piston, and the engagement between the elastic member and the sealing device is determined by a tapered recess formed in the sealing device. This is performed by utilizing a curved portion formed in the elastic member.

FIG. 2 shows the exhaust state of the automatic exhaust valve mechanism according to the present invention. In other words, the sliding material 6 is the piston 8
The pin 1 of the sliding material 6 is slid by the reciprocating motion of
2 and the groove 13 provided on the side surface of the piston 8, the sliding material slides on the inner wall of the cylinder 9 at a certain timing. In FIG. 2a, the piston 8 reaches the bottom dead center and the end of the groove 13 pulls up the pin 12, causing the exhaust port 11 to
is in an open state. At this time, the sliding member 6 is supported by leaf springs 7 from both sides.

FIG. 2b shows a state in which the piston 8 has reached the top dead center and the sliding member 6 is being pushed down. At this time, the concave portion on the side surface of the sliding member 6 and the curved portion of the leaf spring 7 engage with each other, and the tapered portions of both of them engage the sliding member 6.
receives a downward force, causing the exhaust port 11 to close to the valve seal 10
is closed and the engine moves to the intake/expansion stroke.

〔Effect of the invention〕

As described above, since the exhaust valve opens and closes without sliding between the exhaust port and the valve seal, deterioration in performance due to wear of the valve seal surface can be reduced.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a cross section of a main part of a He expansion engine according to an embodiment of the present invention. In a, the piston 8 reaches the bottom dead center, the sliding member 6 is pulled up, and the valve seal 10 is removed from the exhaust port 11. It was pulled apart and finished expanding.
This is where He gas is being exhausted.

In b, the piston 8 reaches the top dead center and is not involved in the operation of pressing the valve seal 10 at the tip of the sliding member 6 against the exhaust port 11, and when the sliding member is pushed down halfway, it begins to slide at a certain point. The concave portion of the member 6 and the curved portion of the leaf spring 7 engage with each other, and the force of the leaf spring acts on both tapered portions, so that the valve seal closes the exhaust port 11.

In the automatic exhaust valve having the structure according to the present invention, the valve seal and the exhaust port open and close without sliding, so the life of the exhaust valve is greatly improved compared to conventional methods, and the initial performance of the engine can be maintained for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the vicinity of the intake and exhaust valves of a He expansion engine according to the prior art, and FIG. 2 is a sectional view showing a main part of an embodiment of the present invention. 6... Sliding material (sealing device), 7... Leaf spring (elastic member), 8... Piston, 9... Cylinder,
10... Valve seal (sealing device), 11... Exhaust port.

Claims (1)

[Scope of Claims] 1. A cylinder for adiabatic expansion of inhaled gas, a piston provided in the cylinder so as to be able to move back and forth, and an exhaust port provided near the bottom of the cylinder for discharging the gas. and, provided in the cylinder, for engaging with the piston at predetermined positions before the piston reaches top dead center and bottom dead center, respectively, and moving in the movement direction of the piston to open and close the exhaust port. a sealing device, one end of which is fixed to the cylinder, and the other end of which is engaged with the sealing device that moves from the predetermined position before the piston reaches the top dead center to engage with the piston; applying a force in the direction of closing the exhaust port to the piston until the piston engages with the seal device again at the predetermined position before the piston reaches bottom dead center and separates the seal device from the exhaust port; An expansion engine comprising: an elastic member that continues to engage with the sealing device and continue to apply a force in the direction of closing the exhaust port. 2. The expansion engine according to claim 1, wherein the sealing device has a tapered recess, and the elastic member has a curved part that engages with the recess. . 3. The sealing device according to claim 1, wherein the sealing device includes a moving member that can engage with the piston and the elastic member, and a valve seal fixed to the moving member. expansion engine.