JPH0730929Y2 - Heat engine - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a hot gas engine such as a crankcase pressurizing type unlubricated compressor or a heat-driven engine, and particularly to prevent ingress of lubricating oil into its working space. The present invention relates to the internal shape of the power rod for carrying out.

[Conventional technology]

FIG. 8 is a cross-sectional configuration diagram of a conventional hot gas engine disclosed in, for example, Japanese Patent Laid-Open No. 60-212660. This figure shows a displacer type Stirling engine which is one of typical hot gas engines to which the present invention can be applied. In the figure, reference numeral 1 is a displacer, which causes a flow of high-pressure working fluid in the cylinder 2, and causes a heater 3, a regenerative heat exchanger 4, and a cooler 5.
In addition to the action of, the pressure change is generated in the cylinder. Reference numeral 6 denotes a power piston for taking out a pressure change generated in the cylinder as an output, and a power rod 7, a crosshead 8 and power connecting rods 9a, 9 connected to the power piston.
b, The motion is transmitted to the crankshaft 10 to obtain a rotation output to the outside.

A displacer connecting rod 11 is further connected to the crankshaft 10, and a displacer rod 12 is connected to the other end of the connecting rod 11. The displacer rod 12 penetrates the crosshead 8, the power rod 7, and the power piston 6. However, the exercise is transmitted to the displacer 1. 13
Is a shaft seal that keeps the portion of the displacer rod 12 penetrating the power piston 6 airtight, and usually various packings such as O-rings are used. Reference numeral 14 is a guide ring attached to the displacer 1, and 15 is a bearing between the crosshead 8 and the power rod 7. The displacer 1 is supported by the guide ring 14 and the bearing 15 via the displacer rod 12. It Reference numeral 16 is a crankcase, and 17 is a lubricating oil on the bottom of the crankcase. The lubricating oil 17 is sent to the sliding surfaces of the crankshaft 10, the crosshead 8 and the bearing 15 for lubrication.

[Problems to be solved by the device]

In the Stirling engine having such a configuration, the lubricating oil that lubricates the bearing 15 of the displacer rod 12 enters the upper portion of the bearing 15 as the power piston 6 and the displacer 1 move up and down. Further, it enters the power rod internal space 18 which is a gap between the power rod 7 and the displacer rod 12 as droplets, adheres to the shaft seal 13 and enters the working space 19 which is the upper space of the power piston 6.

As a result, the invading lubricating oil adheres to the heater 3, the regenerative heat exchanger 4, and the cooler 5, deteriorating the heat transfer performance and deteriorating the performance of the Stirling engine. Further, when the engine is rotated at a high speed, the oil accumulated in the power rod internal space 18 suddenly splashes and the performance of the engine is significantly deteriorated.

The present invention has been made to solve the above-mentioned problems, and the oil accumulated in the internal space of the power rod can be efficiently returned to the bottom side of the crankcase. The object is to obtain a heat engine that can reduce the amount of oil that accumulates in the internal space and prevent the oil from splashing.

[Means for Solving the Problems]

The heat engine according to the present invention includes a displacer that causes a pressure change in a cylinder, a power piston that takes out the pressure change as a mechanical output, and a cylindrical power rod that has the piston and a vent hole below the power piston. And a crosshead that forms a distance chamber with the power piston and a cylinder that has little or no change in volume due to reciprocating motion of the engine, and a reciprocating power piston that is disposed in the buffer chamber below the crosshead. A crank mechanism for converting a motion into a rotary motion of a crankshaft, a displacer rod slidably provided through the inside of the power piston, the power rod, and a crosshead, and connecting the displacer and the crank mechanism, A communication pipe that connects the buffer chamber and the distance chamber, and the communication pipe And a check valve having a flow path of gas in the direction from the buffer chamber to the distance chamber, the distance chamber is averaged to maintain a higher pressure than the buffer chamber, and the power The inner shape of the rod is such that the sliding contact portion between the displacer rod and the crosshead is circumferential and the sliding contact portion is at the lowest position in the power rod internal space. The lubricating oil that has penetrated into the internal space is collected at the sliding contact portion.

[Action]

In the present invention, a check valve having a gas flow path in the direction from the buffer chamber to the distance chamber is provided in a communication pipe that connects the buffer chamber and the distance chamber, so that the power rod internal space above the crosshead is provided. Pressure is higher than the pressure in the buffer chamber below the crosshead, and the internal shape of the power rod is such that the sliding contact part between the displacer rod and the crosshead is circular and this sliding contact part is inside the power rod internal space. Since it is shaped so that it will be at the lowest position in the power rod, the oil that collects in the power rod internal space collects on the sliding contact part by its own weight, and the effect of pushing back the oil due to the pressure difference between the buffer chamber and the power rod internal space becomes effective. The oil accumulated in the internal space of the power rod falls into the buffer chamber and efficiently returns to the bottom of the crankcase, reducing the amount of oil. Ri and the small amount of oil entering into the power piston upper working space of the upper crosshead can be inhibited from splashing oil.

〔Example〕

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

FIG. 1 is a sectional view for explaining a lubricating oil intrusion prevention mechanism for a heat engine according to an embodiment of the present invention.
The same reference numerals as those in FIG. 8 indicate the same parts, and 16 is a crankcase, and the lower structure of the crankcase is omitted here. Reference numeral 12 is a displacer rod, which is composed of a small diameter portion that slides in a through hole formed in the central portion of the power piston 6 and a large diameter portion that slides inside the power rod 7 and the crosshead 8. The shape of the upper surface of the sliding portion of the diameter portion is such that the outer peripheral side is lower than the central side. With such a shape, the displacer rod 12
The sliding contact portion of the cross head 8 with the cross head 8 has a circular shape, and this sliding portion is the lowest position in the power rod internal space 18. 31 is the lower part of the crosshead 8 and the crankcase 16
A buffer chamber, which is an internal space of the crankcase formed by and, 32 is a crosshead 8, a power piston 6, and a cylinder 2.
Is a distance chamber which is a space above the crosshead formed by. The distance chamber 32 is configured such that even if the crosshead 8 and the displacer rod 12 reciprocate, the amount of change in volume thereof is very small or does not change.

Reference numeral 33 is a ventilation pipe (communication pipe) that connects the spaces 31 and 32, and an oil mist separator 34 and a check valve 35 having a flow direction in the direction of the arrow in the figure are arranged in the middle of the pipe. 36 is the power rod 7
A power rod internal space 18, which is a vent hole provided in the space between the power rod 7 and the displacer rod 12,
It communicates with the distance chamber 32. Reference numeral 37 denotes a sliding portion of the crosshead 8 and 38 denotes a sliding portion of the displacer rod bearing portion, which have lubricating oils permeated therein and have a sealing function.

Next, the function and effect will be described.

Normally, this Stirling engine is operated while the inside of the crankcase is pressurized. The crosshead 8 and the power piston 6 repeat up and down reciprocating movements in synchronization with the rotation of the crankshaft. At this time, since the volume of the buffer chamber 31 changes as the crosshead 8 reciprocates, its pressure also changes. However, since the distance chamber 32 has a small volume change and the amount of gas leaked from the working space 19 is usually small, its pressure shows a substantially constant value.

Now consider the case where the vent tube is blocked. In this case, if the sliding surface 37 of the crosshead 8 has a good sealing property, the buffer chamber 31
The pressure Pb of P and the pressure Pd of the distance chamber 32 are normally observed as shown in FIG. That is, the average pressure of the two pressures Pb and Pd becomes substantially equal.

Next, consider the case where the piping shown in FIG. 1 is provided. When the crosshead 8 is located below the reciprocating section, the pressure Pb in the buffer chamber is higher than the pressure Pd in the distance chamber and is in the range indicated by A in FIG. In this time zone, the gas is absorbed from the buffer chamber 31 to the distance chamber 32 through the check valve 35. That is, by providing the check valve 35, the buffer chamber 31 has a function equivalent to that of the compressor. In this case, the relationship between Pb and Pd is as shown in FIG. 3, and the average pressure of Pd is Pb. Higher than the average pressure of. At this time, the ventilation pipe 33
Since the oil mist separator 34 is attached to the oil mist, the lubricating oil mist contained in the gas flowing from the buffer chamber 31 is separated, and only the dry gas flows into the distance chamber 32.

As is well known here, the lubricating oil such as the bearing of the crankshaft scatters, passes through the bearing gap 38, and enters the power rod internal space 18. The reciprocating motion of the displacer rod 12 in the lubricated state causes the lubricating oil on the sliding surface 38 to be pumped up by an amount substantially proportional to the rotational speed of the engine. Conventionally, the lubricating oil pumped up in this way penetrates into the working space 19 through the power rod internal space 18, causing various inconveniences.However, as we invented, the distance chamber 32 and the buffer chamber 31 A check valve mechanism is installed between
By controlling the pressure in the spaces 31 and 32 by the mechanism and further connecting the power rod internal space 18 and the distance chamber 32 with the ventilation hole 36, the bearing of the displacer rod 12 is formed.
The pressure relationship between the upper and lower spaces of 15 can be controlled as shown in FIG.

By maintaining the pressure relationship in this manner, the lubricating oil pumped up through the sliding surface 38 of the bearing 15 of the displacer rod 12 is pumped by the pressure difference (Pd-Pb) into the buffer chamber.
It can be pushed back to the bottom of the crankcase 16 through 31.

Further, in this embodiment, the outer peripheral side of the sliding portion upper surface 30a is made lower than the central side, so that the pumped-up lubricating oil can be pushed back to the bottom of the crankcase 16 more effectively. That is, due to the shape of the displacer rod 12 as described above, the oil accumulated in the power rod internal space 18 gathers on the outer peripheral portion (near the sliding portion 38) of the sliding portion upper surface 30a due to the weight of the oil, and the pressure difference that pushes back the oil. Effectively works, oil is dropped into the buffer chamber 31, and the amount of oil accumulated in the power rod internal space 18 is reduced. Therefore, even if the engine rotates at a high speed, the amount of oil that enters the operating space 19 is suppressed, and the deterioration of the engine performance due to oil rise is reduced.

In this embodiment, the structure of the sliding part of the displacer rod 12 is a structure in which the outer peripheral side of the sliding part upper surface 30a is lower than the center side thereof, but the structure of the displacer rod sliding part is not limited to this. The example will be described below.

FIG. 4 shows an oil permeation preventive device according to a second embodiment of the present invention. In this embodiment, the sliding part of the large diameter portion of the displacer load 12 has a chamfered outer peripheral portion of its upper surface 30b. The other structure is the same as that of FIG. 1, and in this case also, the same effect as that of the above-mentioned embodiment is obtained.

FIG. 5 shows a third embodiment of the present invention. In this embodiment, the diameter of the displacer rod 12 is not changed as in the above embodiments, but the inner diameter of the through hole into which the displacer rod 12 of the power rod 7 is inserted is set to the power rod 7 and the displacer rod 12 of the crosshead 8. The inner diameter of the through hole is made larger than the inner diameter of the sliding portion, and the shape of the lower end portion of the through hole is such that the inner diameter becomes gradually smaller toward the lower sliding portion. That is, the inner diameter of the power rod 7 is made larger than the inner diameter of the sliding portion of the crosshead 8 with the displacer rod, and the inner peripheral portion of the sliding portion upper surface 40a of the crosshead 8 is made lower than the outer peripheral portion. Also in this case, the oil adhering to the inner wall of the displacer rod or the power rod gathers on the displacer rod sliding portion 38 due to its own weight, whereby the action of pushing back the oil works effectively as in both the above-mentioned embodiments.

In the embodiment shown in FIG. 5, the inner peripheral portion of the upper surface 40a of the sliding portion of the cross head 8 is lower than the outer peripheral portion. However, as in the fourth embodiment shown in FIG. Head 8
The sliding portion with the displacer rod 12 may have a shape in which the inner peripheral side of the upper surface 40b thereof is chamfered, and in this case, the same effect is obtained.

Finally, a fifth embodiment of the present invention will be described with reference to FIG. In this embodiment, as shown in FIG.
A piston ring 46 is mounted on the bearing surface of the displacer rod 12, and a piston ring 47 is mounted on the bearing surface of the displacer rod 12 to improve the sealing function of each sliding surface. With such a configuration, the pressure control shown in FIG. 3 becomes easier than in the case of the embodiment shown in FIG.

Further, in this embodiment, an oil splash prevention plate 48 made of a porous object (sponge, foam metal, etc.) is provided so that even if oil passes through the sliding surface 38 and rises above the lubrication sliding surface. , The lubricating oil can be prevented from splashing upwards,
It is possible to prevent oil from adhering to the shaft seal 13.

In the embodiment of FIG. 7, the piston ring and the oil splash preventer are installed in the embodiment of FIG. 1, but the piston ring and the oil splash preventer are separately or simultaneously installed in the fourth embodiment.
It goes without saying that it may be installed in any of the embodiments shown in FIGS.

[Effect of device]

As described above, according to the heat engine of the present invention, the displacer that causes a pressure change in the cylinder, the power piston that takes out the pressure change as a mechanical output,
A crosshead which is disposed below the power piston and is connected to the piston by a cylindrical power rod having a ventilation hole, and which forms a distance chamber with a small or no volume change accompanying the reciprocating motion of the engine together with the power piston and the cylinder. A crank mechanism that is disposed in the buffer chamber below the crosshead and that converts the reciprocating motion of the power piston into a rotary motion of a crankshaft, and freely slides through the power piston, the power rod, and the inside of the crosshead. A displacer rod that connects the displacer and the crank mechanism, a communication pipe that connects the buffer chamber and the distance chamber, and a direction provided from the buffer chamber to the distance chamber. A check valve having a gas flow path as In order to maintain the pressure higher than that in the buffer chamber, the internal shape of the power rod is such that the sliding contact portion between the displacer rod and the crosshead is circumferential and the sliding contact portion is in the internal space of the power rod. Since the lubricating oil that has entered the internal space of the power rod is collected at the sliding contact part, the oil that has accumulated in the internal space of the power rod can be efficiently stored in the crankcase. The amount of oil accumulated in this internal space can be reduced by pushing back to the side, and there is an effect that the amount of lubricating oil in the working space can be prevented from increasing even if the engine is rotated at a higher speed.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining an oil intrusion prevention mechanism of a heat engine according to a first embodiment of the present invention, and FIGS. 2 and 3 show pressure conditions during operation of a distance chamber and a buffer chamber, respectively. FIGS. 4 to 7 are schematic sectional views for explaining an oil intrusion prevention mechanism according to second to fifth embodiments of the present invention, and FIG. 8 is a schematic sectional view showing a conventional heat engine. Is. 1 ... Displacer, 2 ... Cylinder, 6 ... Power piston, 7 ... Power rod, 8 ... Crosshead, 12 ... Displacer rod, 15 ... Bearing, 16 ... Crankcase, 18 ... Power rod internal space, 30a, 30b ... Displacer rod Upper surface of sliding part, 31 ... Buffer chamber, 32 ... Distance chamber, 33 ...
Vent pipe, 34 ... Oil mist separator, 35 ... Check valve, 36 ... Vent hole, 38 ... Displacer rod sliding part, 40a, 40b ... Crosshead sliding part upper surface, 46, 47 ... Piston ring, 48 ...
Oil splash prevention body. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] 1. A displacer for producing a pressure change in a cylinder, a power piston for taking out this pressure change as a mechanical output, and a piston for connecting the piston and a cylindrical power rod below the power piston. And a crosshead that forms a distance chamber with a small or no change in volume due to reciprocating motion of the engine together with the power piston and the cylinder, and is disposed in a buffer chamber below the crosshead to crank the reciprocating motion of the power piston. A crank mechanism for converting the shaft into rotary motion; a displacer rod slidably penetrating the inside of the power piston, the power rod, and the crosshead for connecting the displacer and the crank mechanism; and the buffer chamber. And a communication pipe communicating between the distance chamber and the distance chamber, and provided in the communication pipe. And a check valve having a gas flow path in the direction from the buffer chamber to the distance chamber, so that the distance chamber is kept at an average pressure higher than that of the buffer chamber, and The internal shape is such that the sliding contact portion between the displacer rod and the crosshead is circumferential and the sliding contact portion is at the lowest position in the power rod internal space, and the power rod internal space is A heat engine, characterized in that the lubricating oil that has entered into the sliding contact portion is collected at the sliding contact portion.