JPH0259390B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust valve device for a reciprocating low-temperature expansion engine that has a reciprocating mechanism such as a piston and generates extremely low temperatures. The present invention relates to an exhaust valve device suitable for automatically opening and closing an exhaust valve at the following positions.

Conventionally, in the exhaust valve device of a reciprocating type low-temperature expansion engine, the exhaust valve in the low-temperature section is directly connected to the valve operating mechanism consisting of the crankshaft, cam, valve pull rod device, etc. in the room-temperature section. It is necessary to prevent leakage of working gas such as helium gas (hereinafter referred to as working gas), which serves as a refrigerant, and to prevent heat from entering from room-temperature areas to low-temperature areas.
The disadvantage was that the structure was complicated. Therefore,
Recently, an exhaust valve system has been devised that eliminates the need to install the valve mechanism consisting of a crankshaft, cam, valve pull rod device, etc. in a room-temperature section and uses the reciprocating motion of a piston to open and close the exhaust valve. has been done.

An example of a conventionally known exhaust valve device that uses reciprocating motion of a piston to open and close an exhaust valve will be described with reference to FIG. FIG. 1 is a cross-sectional view of the exhaust valve device described in Japanese Utility Model Publication No. 52-168364, in which 1a is an exhaust valve body having an exhaust valve 2a on its lower edge, and a hole 3 with a predetermined diameter and depth extending from the lower end. A spring 4 and a flanged valve rod 5 are inserted into the hole 3, and a stopper 6 is screwed into the hole 3. 7 is a valve seat body, and below it is a valve seat 8,
An exhaust hole 9a is provided, and a hole 10 is provided that penetrates from the exhaust hole 9a in the axial direction toward the upper end.
11 is a stopper screwed onto the upper end of the exhaust valve body 1a;
12 is held by a spring receiver 13 screwed onto the upper end of the valve seat body 7 by means of a spring. 14 is a cylinder, and a valve seat body 7 is screwed into the head of the cylinder to maintain airtightness. 15 is a piston, its top surface and exhaust valve body 1
The lower end surface a is sufficiently thin and flexible, and has a length such that it can fully extend straight and open the exhaust valve body 1a when the piston 15 moves toward the bottom dead center side and moves to the opening position of the exhaust valve 2a. are connected by a wire 16. Note that 17 is an expansion chamber.

In the exhaust valve device having such a structure, the exhaust valve 2a
While the valve body is seated on the valve seat 8 and in the closed state, the pressure in the expansion chamber 17 is always higher than the pressure in the exhaust hole 9a due to the working gas pressure taken in from the intake valve (not shown), so the exhaust valve body A pushing force is applied to 1a.
In this case, the spring force of the spring 12 is set smaller than the push-up force, and the exhaust valve 2a remains closed unless another push-up force is applied to the exhaust valve body 1a. Due to the expansion of the working gas sucked into the expansion chamber 17, the piston 15 moves downward toward the bottom dead center.
When the exhaust valve 2a reaches the open position, the wire 16 is fully extended straight, and the downward force of the piston 15 is applied to the exhaust valve body 1a via the wire 16, so that the exhaust valve 2a begins to open. When the exhaust valve 2a opens even slightly and the exhaust hole 9a and the expansion chamber 17 communicate with each other, the pushing up force previously applied to the exhaust valve body 1a is released, and the exhaust valve 2a is immediately fully opened by the spring force of the spring 12. becomes. This state is maintained until the piston 15 passes through the bottom dead center and rises again toward the top dead center until the top surface of the piston 15 comes into contact with the tip surface of the flanged valve rod 5. During this period, the operation inside the expansion chamber 17 Gas is exhausted from the exhaust hole 9a. After coming into contact with the tip surface of the flanged valve stem 5, the piston 15 further rises and pushes up the flanged valve stem 5, but in this case, the spring force of the spring 4 is set to be larger than the spring force of the spring 12. Therefore, the exhaust valve body 1a and the flanged valve rod 5 rise together, and the exhaust valve 2a seats on the valve seat 8 and closes. The spring 4 serves as a cushion until the exhaust valve 2a closes and the piston 15 reaches the top dead center. after that,
The piston 15 descends again toward the bottom dead center, but
At this point, the suction of the working gas into the expansion chamber 17 begins, and even if the top surface of the piston 15 separates from the tip surface of the flanged valve rod 5, the pressure of the working gas suctioned into the expansion chamber 17 closes the exhaust valve 2a. Maintain valve status. Thereafter, the above operation is repeated.

The top surface of such a piston 15 and the exhaust valve body 1a
In an exhaust valve device whose lower end surfaces are connected by a wire 16 and which opens and closes the exhaust valve 2a using the reciprocating motion of the piston 15, the valve mechanism consisting of the crankshaft, cam, valve pull rod device, etc. is kept at room temperature. However, on the other hand, since the exhaust valve 2a is closed only by the working gas pressure when the working gas expands, the valve seat 8 of the exhaust valve 2a
The pressing force against the piston 15 is insufficient, which tends to cause leakage of working gas, and it is necessary to connect one end of the wire 16 to the top surface of the piston 15, making assembly difficult. The disadvantage was that most of the components were concentrated on the cylinder side, making maintenance and inspection cumbersome.

An object of the present invention is to provide an exhaust valve device that can improve the performance of a reciprocating cold expansion engine.

The present invention relates to an exhaust valve device that is used in a reciprocating type low-temperature expansion engine and discharges working gas that has been sucked into a cylinder constituting the engine and expanded to the outside of the cylinder. an exhaust hole provided in the cylinder, an exhaust valve body that is movable upwardly by abutting the top of the piston when the piston moves from bottom dead center to top dead center in the cylinder; An exhaust valve is provided on the outer circumferential surface and closes the exhaust hole when the piston comes into contact with the exhaust valve body and the piston reaches the top dead center position. The exhaust valve is equipped with a valve pull rod that engages the collar of a guide means provided on the piston at a position immediately before the bottom dead center when the piston moves to the dead center, and pulls down the exhaust valve body, thereby reducing the dead space. This is to keep the working gas to a small value and to allow good intake and exhaust of the working gas into the cylinder.

An embodiment of the present invention will be described with reference to FIGS. 2 to 5. Note that in FIGS. 2 to 5, parts and the like that are the same as those in FIG. First, in FIGS. 2 and 3, 9b is an exhaust hole provided through the upper end side wall of the cylinder 14, and 2b is a position corresponding to the exhaust hole 9b, and is arranged so as to slide on the inner surface of the side wall of the cylinder 14. It is a ring-shaped exhaust valve provided in the exhaust valve body 1b with a back-up spring 18.
Through the ring mounting, it is retained. In this case, the exhaust valve 2b is installed so that a predetermined gap 19 is formed between the upper end surface of the exhaust valve body 1b and the inner surface of the head of the cylinder 14 when the exhaust valve 2b is in the closed state. 20a is a valve pull rod that is divided into at least one place on the circumference and has an engaging member 21a at one end, and the other end of the valve pull rod 20a is centered on the axis of the exhaust valve body 1b at the lower end of the exhaust valve body 1b. The exhaust valve body 1b is either fixedly installed or formed integrally with the exhaust valve body 1b. 22 is a guide hole which has a diameter larger than the outer diameter of the valve pull rod 20a and is bored from the top surface side of the piston 15 centering on the exhaust valve body 1b and the axis of the piston 15. It can be temporarily stored and smoothly reciprocated. 23a is a guide rod having a collar 24a having approximately the same diameter as the inner diameter of the valve pull rod 20a at one end, and having a diameter of a portion excluding the collar 24a that is approximately the same diameter as the inner diameter of the engaging member 21a of the valve pull rod 20a. , one end of the guide rod 23a is connected to the guide hole 22
It protrudes further and the other end is implanted at the bottom of the guide hole 22 centering on the axis of the guide hole 22 . 25
is a working gas intake/exhaust hole, and at least one hole is provided to penetrate through the exhaust valve body 2b. 26 is expansion chamber 1
7. Penetrates the exhaust valve body 2b centering on the axis of the exhaust valve body 2b, which communicates the inner space of the valve pull rod 20a with the gap 19, and is provided with an exhaust groove 27 at at least one location on the circumference. Exhaust hole provided at 28
is an intake valve provided at the head of the cylinder 14.

FIG. 2 shows the state when the piston 15 is located at the top dead center. In this state, the intake valve 28 is open, and high-pressure working gas flows into the gap 1.
9. The air is sucked into the expansion chamber 17 through the intake/exhaust hole 25, but since the exhaust valve 2b is closed, the expansion chamber 1
The working gas pressure within 7 is maintained at a constant pressure. Second
When the piston 15 starts to move downward toward the bottom dead center from the state shown in the figure, the intake valve 28 eventually closes, the intake stroke ends, and then the expansion stroke begins. During this time, the exhaust valve 2b is in the closed state. is maintained until just before the end of the expansion stroke due to the working gas pressure and the spring force of the backup spring 18. When the piston 15 further descends, the collar 24a of the guide rod 23a comes into contact with the engaging member 21a of the valve pull rod 20a, the exhaust valve body 1b is pulled down, the exhaust valve 2b slides and becomes open, and the expansion chamber 17 The exhaust hole 9b communicates with the exhaust hole 9b, and exhaust begins.
Thereafter, the piston 15 further descends and reaches the bottom dead center shown in FIG. The valve is kept in an open state by being pressed against the inner surface of the cylinder 14, and the working gas in the expansion chamber 17 is exhausted from the exhaust hole 9b through the intake/exhaust hole 25, the inner space of the valve pull rod 20a, the exhaust hole 26, and the gap 19. be done. When the piston 15 approaches the top dead center, the lower end surface of the engaging member 21a of the valve pull rod 20a comes into contact with the bottom surface of the guide hole 22, or the piston 1
5 comes into contact with the lower end surface of the exhaust valve body 1b, so that the exhaust valve body 1b and the exhaust valve 2b are connected to the piston 15.
The exhaust hole 9b is closed by the exhaust valve 2b, and the valve is closed. Then piston 15
rises and returns to top dead center as shown in FIG. Thereafter, the intake, expansion, and exhaust steps are repeated in the same order. In this case, the opening/closing timing of the exhaust valve 2b is determined based on the collar 2 of the guide rod 23a when the piston 15 is at the top dead center (the state shown in FIG. 2).
4a and the upper end surface of the engaging member 21a of the valve pull rod 20a, the length of the valve pull rod 20a, and the guide hole 22.
This can be done by appropriately selecting the relationship between the depth of , and can be set automatically.

In this embodiment, since there is no need to increase the gap between the piston and the cylinder, the dead space can be controlled to be small, and the engaging member engages with the collar of the guide rod that moves from the top dead center to the bottom dead center together with the piston. The exhaust valve is opened by lowering the valve pull rod, and conversely, the exhaust valve body comes into contact with the top surface of the piston moving from bottom dead center to top dead center, and in this state, the exhaust valve is pushed up to open the exhaust valve. Since the valve is closed, the opening and closing of the exhaust valve can be performed stably and well, and it is possible to prevent the suction of working gas from occurring when the exhaust valve is insufficiently closed, thereby causing an exhaust path for the sucked working gas.

Therefore, the inhaled working gas is sufficiently and well expanded and a decrease in expansion efficiency is suppressed, so that the performance of the reciprocating low-temperature expansion engine can be improved.

Figures 4 and 5 show that the valve pull rod is fixed to the outer periphery of the exhaust valve body so that it reciprocates along the inner surface of the cylinder side wall, and that a guide for the reciprocating movement of the valve pull rod is provided on the outer surface of the piston. In the example in which a groove is provided, Fig. 4 shows the state when the piston is located at top dead center, and Fig. 5 shows the state when the piston is located at the top dead center.
The figure shows the state when the piston is located at the bottom dead center. Figures 4 and 5, Figures 2 and 3
Components that are the same as those in the drawings are designated by the same reference numerals and their explanations will be omitted.
1c is an exhaust valve body having a link-like shape, and the exhaust valve 2 is connected to the outer peripheral surface of the body through a back-up spring 18.
b is ring-mounted and held. Reference numeral 20b is a valve pull rod with an engaging member 21b provided at one end, and the other end is connected to the lower end of the exhaust valve body 1c, and at least two
The exhaust valve body 1c is either fixedly installed or integrally formed with the exhaust valve body 1c. 29 is a guide groove for temporarily housing the valve pull rod 20b and for smoothly reciprocating the valve pull rod 20b.
5 are provided corresponding to the shape and number of valve pull rods 20b from the top surface side. 24b is a collar provided at the upper end of the guide groove 29, and its outer diameter is equal to that of the exhaust valve body 1c.
It is also larger than the inner diameter of the engaging member 21b of the valve pull rod 20b and smaller than the inner diameter of the valve pull rod 20b. The diameter of the longitudinal direction from the top surface of the piston 15 corresponding to the width of the exhaust valve body 1c is set to be smaller than the inner diameter of the exhaust valve body 1c in order to prevent the piston 15 from contacting the inner circumferential surface of the exhaust valve body 1c during reciprocation. is also getting smaller.

Even in the exhaust valve device having such a structure, the same operation as that explained using FIGS. 2 and 3 is achieved, and the exhaust valve 2b automatically opens and closes using the reciprocating motion of the piston 15. That is, when the piston 15 moves downward toward the bottom dead center from the top dead center position in FIG. The exhaust valve 2b opens when the valve pull rod 20b is pulled down, and when the piston 15 moves upward toward the top dead center from the bottom dead center position in FIG. The upper end surface of the brim 24b and the lower end surface of the exhaust valve body 1c come into contact, and the exhaust valve body 1c is pushed up, thereby closing the exhaust valve 2b. In this case as well, the opening/closing timing of the exhaust valve 2b is determined by the timing between the lower end surface of the collar 24b and the engaging member 21b when the piston 15 is at the top dead center (the state shown in FIG. 4).
It can be set appropriately by appropriately selecting the distance between the upper end surfaces and the distance between the upper end surface of the collar 24b and the lower end surface of the exhaust valve body 1c when the piston 15 is at the bottom dead center (the state shown in FIG. 5). .

FIG. 6 shows another embodiment of the collar structure of the valve pull rod and guide rod shown in FIGS. 2 and 3, in which a portion of the lower end of the valve pull rod 20c remains ( Figure 2,
(corresponding to the engaging member 21a in FIG. 3) There are at least two slits 3 in the longitudinal direction at appropriate intervals on the circumference
0 is set. Further, at the upper end of the guide rod 23b, a collar 24c is provided at a position corresponding to the slit 30 and has a width narrower than the slit width and an outer diameter approximately equal to the outer diameter of the valve pull rod 20c. The diameter of the guide rod 23b excluding 24c is approximately the same diameter as the inner diameter of the valve pull rod 20c. When the valve pull rod and the guide rod have such a structure, the mechanical expansion of the lower end of the valve pull rod 20c in the radial direction during reciprocation can be prevented, so that the opening/closing operation of the exhaust valve 2b can be made smoother. , and the opening/closing timing can be maintained appropriately.

7 and 8 show another embodiment in which the exhaust valve is encircled and held in the exhaust valve body. A spring 32 is installed in a compressed state in the spring storage holes 31 bored at appropriate intervals on the circumference, and then the backup spring 18 and the exhaust valve 2b are encircled and held. If a spring other than the backup spring is used to encircle and hold the exhaust valve around the exhaust valve body in this way, the exhaust valve 2b by the backup spring 18 is used.
Even if the pressing force against the inner surface of the cylinder 14 is insufficient, this shortage is compensated for by the spring force of the spring 32, thereby preventing leakage of working gas when the exhaust valve 2b is closed due to insufficient pressing force.

FIG. 9 shows another embodiment in which the exhaust holes are provided in the cylinder side wall. They are provided adjacent to or apart from each other on the circumference of the upper end side wall. In this way, connect the exhaust hole 9c to the cylinder 14.
When provided on the upper end side wall, the shortage of the actual flow path area of the exhaust hole is suppressed, so that the working gas can be exhausted satisfactorily.

FIG. 10 shows another embodiment of the exhaust hole shape, in which an elongated or slender exhaust hole 9d with a width narrower than the sliding amount of the exhaust valve determined by the stroke of the piston is provided on the circumference of the upper end side wall of the cylinder 14. It is installed through the. Even when the exhaust hole is shaped in this manner, the shortage of the actual flow path area of the exhaust hole is suppressed, so that the working gas can be exhausted satisfactorily.

Hereinafter, according to the present invention, the dead space can be suppressed to a small size, and working gas can be taken in and exhausted into the cylinder well, so that a decrease in expansion efficiency can be suppressed and the performance of the reciprocating type low-temperature expansion engine can be improved. There is an effect that it can be done.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional exhaust valve device that uses the reciprocating motion of a piston to open and close an exhaust valve, and FIGS. 2 to 5 illustrate an embodiment of the present invention. , FIGS. 2 and 3 are cross-sectional views of an exhaust valve device in which a valve pull rod is provided in the center of the exhaust valve body,
Figures 4 and 5 are cross-sectional views of an exhaust valve device in which a valve pull rod is provided on the outer periphery of the exhaust valve body, and Figure 6 shows another example of the collar structure of the valve pull rod and guide rod. 7 is a sectional view showing another embodiment in which an exhaust valve is mounted and held in an exhaust valve body, FIG. 8 is a sectional view taken along line A-A in FIG. 7, and FIG. 10 is a partial internal plan view showing another embodiment in which the exhaust hole is provided in the upper end side wall of the cylinder, and FIG. 10 is a partial internal plan view showing another example of the exhaust hole shape. 1b, 1c...exhaust valve body, 2b...exhaust valve, 9
b, 9c, 9d...Exhaust hole, 14...Cylinder,
15... Piston, 17... Expansion chamber, 18... Backup spring, 19... Gap, 20a, 20
b, 20c... Valve pull rod, 21a, 21b... Engaging member, 22... Guide hole, 23a, 23b... Guide rod, 24a, 24b, 24c... Brim, 25...
Intake/exhaust hole, 26... Exhaust hole, 27... Exhaust groove, 28... Intake valve, 29... Guide groove, 30...
Slit, 31... Spring storage hole, 32... Spring.

Claims (1)

[Scope of Claims] 1. In an exhaust valve device used in a reciprocating low-temperature expansion engine, which discharges working gas sucked into a cylinder constituting the engine and expanded to the outside of the cylinder, the upper side wall of the cylinder is an exhaust hole provided through the cylinder; and an exhaust valve body provided in the cylinder and movable upward by coming into contact with the upper part of the piston when the piston moves from the bottom dead center to the top dead center in the cylinder. an exhaust valve that is provided on the outer peripheral surface of the exhaust valve body and closes the exhaust hole when the exhaust valve body is pushed up by being in contact with the piston and the piston reaches the top dead center position, and the exhaust valve body The exhaust valve body is engaged with a collar of a guide means provided on the piston at a position immediately before the bottom dead center when the piston moves from the top dead center to the bottom dead center in the cylinder, and pulls down the exhaust valve body. An exhaust valve device characterized by comprising a valve pull rod. 2. The valve pull rod is provided along the axis of the exhaust valve body, a guide hole is bored in the piston from the top surface side of the piston so as to be able to guide the valve pull rod, and the guide hole is provided in the guide hole. 2. The exhaust valve device according to claim 1, wherein the flange is provided on a guide rod. 3. The valve pull rod is provided with at least two slits in the longitudinal direction, leaving a portion of the end corresponding to the top surface of the piston to form the engaging member, and the collar is capable of reciprocating within the slits. The exhaust valve device according to claim 2, which has a shape. 4. The valve pull rod is provided on the outer periphery of the exhaust valve body, a guide groove is formed on the outer circumferential surface of the piston so that the valve pull rod can be guided, and the collar is provided on the piston in correspondence with the guide groove. An exhaust valve device according to claim 1.