JPH03117661A - Rod seal device for stirling engine - Google Patents

Abstract

PURPOSE:To reduce an amount of consumption oil and to prevent reduction of an output by providing a relief valve which is located in a communicating passage for intercommunicating an oil pump and a closed space and maintains the delivery pressure of the oil pump at a given value. CONSTITUTION:An oil pump 27 is mounted to the one end of a crank shaft 17. The oil pump 27 feeds a delivery pressure to a closed space 23 through a crank case 16, an expansion cylinder 11, and a communicating passage 28 formed in an intermediate member 18. A relief valve 29 to maintain the delivery pressure of the oil pump 27, fed in the closed space 23, at a given value is located in the communicating passage 28. This constitution always increases a pressure in the closed space 23 to a value higher than a pressure in an intermediate chamber 30. Thereby, rise of oil from the crank shaft side 17 to the working piston 12 side can be prevented.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention has the following features: 1. This invention relates to a rod seal device for a Stirling engine that prevents oil from rising into the working space.

(Prior Art) A conventional rod seal device for a Stirling engine of this type is disclosed in Japanese Patent Application Laid-Open No. 64-87854. This device has an output mechanism that is connected between an operating piston and an output extraction mechanism connected to the operating piston via a rod.
The first seal member is supported by the fixed member so that the seal portion has a high sealing ability against the movement of fluid from the output extraction mechanism side to the working piston side and contacts the rod, and the first seal member and the working piston, the fixed member has a first sealing portion within the fixed member in contact with the rod, the sealing portion of which has a high sealing ability against the movement of fluid from the working piston side to the output extraction mechanism side. A second seal member that forms a space between the seal member and the second seal member is supported to maintain the space formed between both seal members at the minimum pressure of the pressure fluctuation in the rear space of the working piston, and from the output extraction mechanism side. Prevents oil from rising to the working piston side.

(Problems to be Solved by the Invention) However, the conventional device described above has the following problems.

That is, although the first seal member has a high sealing ability against the movement of fluid from the output extraction mechanism side to the working piston side, the oil film thickness remains on the outer circumference of the rod and the second seal member Move to the member side. However, the second seal member has properties opposite to the first seal member, and has a high sealing ability against the movement of fluid from the working piston side to the output extraction mechanism side, and vice versa. Therefore, if the distance between the two seal members is not made larger than the stroke of the working piston, the space behind the working piston will pass through the second seal member when the working piston moves to the top dead center. The oil film on the outer periphery of the rod that has entered the inside is scraped off by the second seal member into the space on the back of the working piston when the working piston moves to the bottom dead center. A so-called pump-up phenomenon occurs. Therefore, in order to prevent this pump-up phenomenon, it is necessary to increase the distance between both seal members, which results in an increase in the size of the Stirling engine.

Therefore, the present invention provides, in the Stirling engine,
To prevent oil from rising from the output extraction mechanism side to the working piston side without increasing the size of the engine,
This is a technical issue.

[Structure of the invention]

(Means for Solving the Problems) Means for solving the above-mentioned technical problems are such that the rod seal device of the Stirling engine is connected to a rod that connects the working piston for the Stirling engine and its output extraction mechanism, and the rod an intermediate member that supports via a bearing member, the intermediate member being located between the actuating piston and the intermediate member, and having a sealing portion thereof having a high sealing ability against movement of fluid from the output extraction mechanism side to the actuating piston side. a first seal member supported by the intermediate member so as to be in liquid-tight contact with the rod, and a seal portion located between the first seal member and the output extraction mechanism; a second sealing member supported by the intermediate member so as to be in liquid-tight contact with the rod and forming a sealed space between the first sealing member and the first sealing member within the intermediate member; and a second sealing member that is discharged into the sealed space. An oil pump that applies pressure, and a relief valve that is provided in a communication passage that communicates the oil pump and the sealed space and maintains the discharge pressure of the oil pump applied to the sealed space at a predetermined pressure. The structure is as follows.

The Stirling engine rod seal device mentioned above is
An intermediate chamber between the actuating piston and the first seal member may be communicated with a space in which the output extraction mechanism is accommodated by a communication means.

(Function) According to the above-described means, by applying a predetermined discharge pressure of the oil pump to the sealed space, the pressure in the sealed space is lowered by the pressure in the intermediate chamber between the actuating piston and the first sealing member. (the sealing pressure of the first sealing member is equal to or higher than the tension force of the spring). Therefore, oil can be prevented from rising from the output extraction mechanism side to the working piston side without increasing the size of the Stirling engine.

Furthermore, when the intermediate chamber and the space in which the output extraction mechanism is accommodated are communicated with each other by the communication means, the pressure amplitudes of the intermediate chamber and the space can be reduced, so that the first and second The pressure acting on the seal members can be reduced, and the durability of both seal members can be improved.

(Example) Hereinafter, an example of a rod seal device for a Stirling engine according to the present invention will be described based on the drawings.

FIG. 1 shows an expansion cylinder portion (the compression cylinder portion is omitted) of a starling engine.

The working piston 12 within the expansion cylinder 11 defines an expansion chamber 13 in its head. The working piston 12 is
It is connected via a rod 14 to a crankshaft 17 housed in a crank chamber 20 formed in a crankcase 16 . The deflection of the rod 14, that is, the deflection of the operating piston 12, is regulated by a bearing member 19 provided on the intermediate member 18, as shown in FIG. As a result, the actuating piston 12 and the rod 14 can reciprocate on the same axis.

The intermediate member 18 is provided with an oil scraper seal (a seal portion) such that its lip portion (seal portion) has a high sealing ability against the movement of fluid from the crank chamber 20 to the working piston 12 side and is in liquid-tight contact with the rod 14. A first seal member) 21 is supported. Furthermore, in this embodiment, the intermediate member 18 has a seal portion between the oil scraper seal 21 and the crank chamber 20 that has a high sealing ability against movement of fluid from the working piston 12 side to the crank chamber 20. A seal ring (
A second seal member) 22 is supported. Thereby, a sealed space 23 is formed within the intermediate member 18 between the scraper seal 21 and the seal ring 22. Note that the seal ring 22 is attached to the bearing member 1 fitted to the intermediate member 18.
Positioning members 25 and 26 are supported on the inner periphery of the scraper seal 21 and the seal ring 22, and are positioned between the scraper seal 21 and the seal ring 22 in cooperation with a plug 24 that is screwed and fixed to the intermediate member 19. is interposed.

A crankshaft 17 for extracting output to the outside is rotatably supported within the crankcase 16, and a well-known oil pump 27 is mounted at one end of the crankshaft 17.
is provided. The oil pump 27 sucks oil stored in the crankcase 16 and supplies oil for lubrication to the sliding parts of the crankshaft 17 via a supply passage (not shown). Communication path 2 formed in the expansion cylinder 11 and the intermediate member 18
The discharge pressure is supplied to the closed space 23 via the pipe 8.

A relief valve 29 is provided in the communication passage 28 to maintain the discharge pressure of the oil pump 27 supplied into the sealed space 23 at a predetermined pressure (below).

Further, in this embodiment, an intermediate chamber 30 formed between the actuating piston 12 and the scraper seal 21 communicates with the crank chamber 20 through a conduit 31. They are communicated via a buffer tank 32 and a filter 33.

In this embodiment having the above configuration, by applying a predetermined discharge pressure of the oil pump 27 to the closed space 23, the pressure inside the closed space 23 is reduced to the pressure inside the intermediate chamber 30, as shown in FIG. (The sealing pressure of the scraper seal 21 is equal to or higher than the spring tension force)
be able to. Further, by communicating the intermediate chamber 30 and the crank chamber 20 via the communication pipe 31, etc., the pressure amplitude can be reduced as shown in FIG. 3, and the fluctuating pressures can be made to have substantially the same phase. Therefore, according to this embodiment, it is possible to prevent oil from rising from the crank chamber 20 to the working piston 12 side without increasing the size of the Stirling engine.

In addition, the intermediate chamber 30 and the crank chamber 2 are connected to each other by the communication pipe 31.
0 can be communicated with each other to reduce the pressure amplitudes in the intermediate chamber 30 and the crank chamber 20, respectively, so that the pressure acting on the scraper seal 21 and the seal ring 22 can be reduced, and the durability of both seal members can be reduced. can improve sex.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to prevent oil from rising from the output extraction mechanism side to the working piston side without increasing the size of the engine, reducing oil consumption and reducing the working gas. It is possible to prevent a decrease in output due to contamination.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a rod seal device for a Stirling engine according to the present invention, FIG. 2 is an enlarged sectional view of section A in FIG. 1, and FIG. 3 is an embodiment of the rod seal device shown in FIG. FIG. 3 is a characteristic diagram showing pressure fluctuations in an intermediate chamber, a closed space, and a crank chamber in an example. 12... Working piston, 14... Rod, 16...
・Crank case, 17... Crankshaft (output extraction mechanism), 18... Intermediate member 19... Bearing member,
20... Crank chamber, 21... Oil scraper seal (first seal member), 22... Seal ring (
second seal ring), 23...closed space, 27...
- Oil pump, 28... Communication path, 29... Relief valve, 30... Intermediate chamber, 31... Communication pipe (communication means).

Claims (2)

[Claims] (1) A rod that connects a working piston for a Stirling engine and its output extraction mechanism, an intermediate member that supports the rod via a bearing member, and a seal located between the working piston and the intermediate member. a first sealing member supported by the intermediate member so as to have a high sealing ability against movement of fluid from the output extraction mechanism side to the working piston side and to be in liquid-tight contact with the rod; The first seal member is located between the first seal member and the output extraction mechanism, and is supported by the intermediate member such that its seal portion is in liquid-tight contact with the rod, and is disposed within the intermediate member. a second sealing member forming a sealed space between;
an oil pump that applies the discharge pressure to the sealed space;
A rod seal device for a Stirling engine, comprising: a relief valve provided in a communication passage communicating the oil pump and the sealed space to maintain a discharge pressure of the oil pump applied to the sealed space at a predetermined pressure. (2) Claim (1) characterized in that an intermediate chamber between the actuating piston and the first sealing member is communicated with a space in which the output extraction mechanism is accommodated by a communication means.
Stirling engine rod seal device as described in.