JPS6016758Y2 - Joint structure of cylinder and head of hot gas machine - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a joint structure between a cylinder and a head in a hot gas machine such as a Stirling engine, a Stirling cycle refrigerator, or a Stirling cycle heat pump.

Figure 1 conceptually shows the principle of a Stirling engine, which is known as a typical hot gas machine. 1 is a heating heater, 12 is a cooling cooler, and 3 is a regenerator. and the regenerator 3 constitute a heat exchanger.

4 and 5 are a high-temperature cylinder and a low-temperature cylinder. Both cylinders 4.5 consist of a cylinder head 41.51 and a cylinder block 42.52, respectively.

6 and 7 are pistons, and 8.9 is a connecting rod.

In a Stirling engine with such a configuration, working gas such as hydrogen or helium is sealed at high pressure inside the engine, and this is heated and cooled from the outside to repeatedly expand and compress the gas to generate power. Since the above-mentioned working gas is a gas that leaks extremely easily, a sealing material such as a gasket used in an internal combustion engine causes a large amount of gas leakage and cannot be used.

Therefore, in a conventional Stirling engine,
As shown in FIG. 2, annular grooves 42a and 52a are cut in the cylinder block 42.
After installing the O-ring, which is an annular sealing member thicker than the depth of this groove, the cylinder head 41.51 is attached to the bolt 1.
1 to the cylinder block 42.52, and the annular groove 42
A joint structure has been adopted in which the O-ring 10 is crushed between the bottom surface of the cylinder head 41.a, 52a and the bottom surface of the cylinder head 41.51, thereby eliminating a gap and creating a gas seal.

Furthermore, since the inner side of the O-ring 10 has a higher pressure than the outer side, the groove shape is changed to the inner circumferential notched groove 42 as shown in FIG.
A structure in which an O-ring 10 is attached to the cutout grooves 42a and 42b is also used as the grooves a and 52b.

Note that this O-ring 18 is normally made of rubber on the low-temperature cylinder 5 side, and a heat-resistant metal O-ring 18 is used on the high-temperature cylinder 4 side.

However, in such a conventional cylinder block and cylinder head joining structure, the annular groove 42a.

52a or the inner peripheral notch grooves 42b, 52b, when processing the grooves,
High precision of the groove depth and the finest surface roughness of the groove bottom are required, and during use, extreme care must be taken to avoid scratches or rust on the bottom of the cylinder head and the bottom of the groove. be.

Particularly in the case of multiple cylinders, if a processing error or scratch or rust occurs even in one cylinder, the entire cylinder becomes unusable, resulting in a significantly poor yield.

Furthermore, a metal O-ring 1 used on the high temperature cylinder 4 side
No. 0 has the disadvantage that it adheres to the bottom surface of the circumferential groove 42a or the inner circumferential notched groove 42b, making it extremely difficult to attach and detach.

This idea was made to solve the above-mentioned problems, and by eliminating the groove machining, the O A spacer with an inner diameter that is approximately the same as the outer diameter of the ring is installed between the cylinder head and cylinder block, an O-ring is inserted inside this spacer, and hard plating is applied to the bottom surface of the cylinder head and the top surface of the cylinder block. The present invention provides a joining structure between a cylinder and a head that solves the conventional drawbacks by preventing the occurrence of scratches, rust, etc.

Hereinafter, this invention will be explained with reference to the embodiment shown in FIG. 4, but the same parts as in the conventional example shown in FIGS. 2 and 3 are given the same reference numerals, and the explanation thereof will be omitted.

Hard plating such as chrome is applied to the lower surface of the cylinder head 41.51 and the upper surface of the cylinder block 42.52 to form a plating layer 12.13.
Between 51 and cylinder block 42, 52, O-ring 1
An annular inner spacer 14 having an inner diameter approximately equal to the outer diameter of the O-ring 10 and a thickness smaller than the O-ring 10 is placed on the outside of the O-ring 10, and the cylinder head 41.51 and the cylinder block 42.52 are tightened with the bolts 11. Gas sealing is performed by crushing the O-ring 10 from above and below.

The spacer mentioned above is usually made of metal, but the spacer on the high temperature cylinder 4 side is particularly suitable for the high temperature cylinder head 41.
In order to prevent heat from escaping from the cylinder block 42 to the cold cylinder block 42, it is desirable to use a heat insulating material such as ceramic tread.

This device has the above-mentioned configuration, and since the inner diameter of the spacer 14 almost matches the outer diameter of the O-ring 10, there is no possibility that the pressure of the working gas will directly affect the O-ring 10 or swell outward. It is.

Also, unthread the bolt 11 and remove the cylinder head 41.51.
If the spacer 14 is removed, the O-ring 10 will be exposed, so the metal O-ring on the high-temperature cylinder 4 side can also be attached and detached very easily.

Furthermore, since the spacer 14 is a separate part from the cylinder block 42, 52, especially in the case of multiple cylinders, the entire cylinder block is used due to machining failures, such as an annular groove or an inner circumferential notch groove that is machined in the cylinder block itself. It is possible to achieve a complete gas seal by making the O-ring collapse distance for each cylinder the same without fear of failure.

The above description is about the joint between the cylinder head and cylinder block of a hot gas machine, but it is not limited to this.By using spacers at joints that require highly accurate sealing, highly accurate depth sealing can be achieved. It eliminates the need for conventional groove machining that requires dimensions and excellent surface finish, greatly increasing productivity and yields.

Further, by applying hard plating to each joint surface, there is no risk of scratches, rust, etc. occurring during use, and there is no need to pay attention to these.

Furthermore, the metal O-ring on the high temperature side can be easily attached and detached, and maintenance is extremely easy.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram schematically showing the principle of a Stirling engine as a representative example of a hot gas machine, and Figures 2 and 3 illustrate the conventional joint structure between cylinder heads of a hot gas machine. FIG. 1 is an enlarged cross-sectional view of the portion surrounded by a dashed line, and FIG. 4 is a cross-sectional view similar to FIG. 2 showing the side structure according to this invention. 4...High temperature cylinder, 5...Low temperature cylinder, 10...O ring, 12, 13...
...Plating layer, 14...Spacer, 41.51
...Cylinder head, 42.52...Cylinder block.

Claims (1)

[Scope of utility model registration request] Hard plating is applied to the upper surface of the cylinder block and lower surface of the cylinder head of the hot gas machine, respectively, and an O-ring is attached to both joint surfaces. A joining structure between a cylinder and a head, characterized in that a spacer having a small thickness is sandwiched between the outer periphery of the O-ring.