JPH06100310B2 - Oil intrusion prevention structure - Google Patents

Description

Description: [Industrial field of application] The present invention relates to an oil-free compressor, a heat engine, or the like, which prevents lubricating oil of its motion mechanism from entering the working space of those engines. The present invention relates to an intrusion prevention structure.

[Conventional technology]

A conventional oil intrusion prevention structure will be described. 7 and 8
The figure shows the schematic structure of a conventional non-lubricated compressor described in "Cryogenics" Vol.17, No.5 (1982), with a particular focus on the oil intrusion prevention structure. In the figure, 21 is a crankcase, 22 is a crankshaft and a flywheel that are rotatably supported by bearings held by the crankcase 21, 23 is a connecting rod fitted to an eccentric pin of the crankshaft 22, and 24 is a connecting rod. A crosshead connected to the other end of 23, 25 is a piston rod fixed to the crosshead 24, and 26 is a piston. 27a is a first packing box fixed to the crankcase 21 side, and a sealing component is incorporated therein, 27b is a second packing box located above the first packing box 27a, and 28 is a space between the packing boxes. A distance space 29, which is a space, is a compression space that is compressed by the reciprocating motion of the piston 26.

FIG. 8 shows the details of the first and second packing box portions. Here, the first packing box 27a will be described as an example. The V-ring seal 30 is mounted on the first packing box 27a, and the inner peripheral portion of the V-ring seal 30 is in close contact with the piston rod 25 to press and slide the piston rod 25. The V ring seal 30 is pressed by the spring 31, and the piston rod 25
It is increasing the pressure on. 32 is a lip seal, V
Similar to the ring seal 30, it is in close contact with the piston rod 25 and is sliding.

FIG. 9 shows a conventional example of an oil intrusion prevention device for a heat-driven engine having a crosshead structure disclosed in Japanese Patent Laid-Open No. 56-38543. In the figure, 41 is a crosshead, 42 is a piston rod, and rod seals 43a and 43b are attached to the piston rod 42 so as to closely slide on the cylindrical surface. Reference numeral 44 denotes a mechanism portion that collects the oil separated by the sliding surface of the cross head 41 and the rod seals 43a and 43b.

Next, the operation will be described.

In the unlubricated compressor and the heat-driven engine shown in FIGS. 7 to 9, the engine is highly reliable by supplying sufficient lubricating oil to the crank mechanism and the crosshead mechanism. On the other hand, invasion of the lubricating oil into the working space causes deterioration of the performance of the engine, etc., so it is necessary to prevent the infiltration of the lubricating oil into the compression space 29. As an example of invasion prevention, in the conventional example, the structure in which the packing device is attached to the piston rod 25 as described above is adopted. A packing device is provided for the purpose of maintaining a high pressure in the compression space 29, and the V ring seal 30 and the lip seal 32,
The rod seal 43 is strongly pressed against the piston rod 25, and the large distance space 28 is provided to prevent the lubricating oil from entering the compression space 29 and the working space of the heat engine.

Further, as shown in FIG. 9, the performance as an intrusion prevention device was satisfied by providing a device for collecting the invading lubricating oil.

[Problems to be solved by the invention]

The conventional oil intrusion prevention structure is configured as described above,
Due to the strong compressive force at the rod seal packing part, mechanical friction loss was excessive, and sufficient reliability could not be obtained due to wear at the sliding part. In addition, it was difficult to reduce the size because an oil recovery device was required and a large distance space was required.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain a highly reliable oil intrusion prevention structure in a small space without increasing friction loss.

[Means for solving problems]

The oil intrusion prevention structure according to the present invention allows the reciprocating sliding portion of the crosshead to have a sealing function, and communicates the upper and lower spaces of the crosshead through a separately installed check valve to control the pressure in the upper and lower spaces. By doing so, the invasion of lubricating oil into the working space and the like is prevented.

[Action]

In the present invention, the newly provided check valve makes the average pressure in the upper space of the crosshead higher than the average pressure in the lower space, and the pressure difference is utilized to make the upper part of the lubricating oil crosshead accompanying the reciprocating motion of the crosshead. Prevent entry into the space.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, the same symbols as those in FIG. 7 indicate the same or corresponding portions.
The structure of the lower part of the crankcase is omitted. 7 is a piston pin that connects the connecting rod 23 and the crosshead 24, and 8 is mounted in the groove of the piston 26, and is a crankcase.
It is a piston ring that slides in close contact with the inner circumference of the cylinder located at the upper part of 21 to seal the compression chamber 29. 4 is the space inside the crankcase (space under the crosshead), 5 is the piston 26
And a crosshead upper space formed between the crosshead 24 and the crosshead 24. A piston ring 11 is attached to the crosshead 24 to appropriately seal the both spaces 4 and 5. Ten
Although omitted in the figure, these are splash particles of lubricating oil required for lubricating the crankshaft and the like, and are scattered as the crankshaft rotates. 6 is a sliding gap between the cross head 24 and the cylinder 9. 1 is space in crankcase 4
Is a communication pipe that communicates with the crosshead upper space 5,
An oil separator 2 and a check valve 3 are provided in the middle of the pipe. The check valve 3 is configured so that gas flows from bottom to top, as indicated by the arrow in the figure.

Next, the function and effect will be described.

Normally, in this type of engine, the crankcase is operated in a pressurized state. The crosshead 24 and the piston 26 repeat up and down reciprocating movements in synchronization with the rotation of the crankshaft. At this time, the space 4 in the crankcase is the crosshead
As the volume changes with 24 round trips, the pressure also changes. However, since the volume of the crosshead upper space 5 does not change and the gas leakage amount of the piston ring 8 is usually small, its pressure shows a substantially constant value.

Now, consider a case where the communication pipe 1 is blocked. In this case, if the piston ring 11 is attached to the crosshead 24 and the airtightness is good, the pressure Pb in the crankcase inner space 4 and the pressure Pd in the crosshead upper space 5 are normally observed as shown in FIG. . That is, the average pressures of the two pressures Pb and Pd are almost equal.

Next, consider the case where the pipe 1 of FIG. 1 is provided. When the crosshead 24 is located below the reciprocating section, Pb is higher than Pd and is in the range indicated by A in FIG. During this time, the gas passes through the check valve 3 and the gas flows in the crankcase space 4
Is sucked into the upper space 5 of the crosshead. That is, by providing the check valve 3, it 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 higher than the average pressure of Pb. Get higher
And since the oil separator 2 is attached to the communication pipe 1,
Lubricating oil mist contained in the gas flowing from the crankcase inner space 4 is separated, and only the dry gas flows into the crosshead upper space 5.

As is well known here, lubricating oil for crankshaft bearings, etc.
Scatter and enter the sliding surface 6 of the crosshead. By the reciprocating operation of the crosshead in the lubricated state, the lubricating oil on the sliding surface 6 is pumped up in an amount substantially proportional to the engine speed. Originally, the lubricating oil pumped up in this way invades the operating space, causing various inconveniences. However, by controlling the pressure between the upper and lower sides of the crosshead 24 as shown in FIG. 3 as in this embodiment, the oil mechanically pumped up causes the pressure difference (Pd-Pb).
As a result, backflow occurs toward the crankcase inner space 4 side below the crosshead. That is, the lubricating oil that flows into the upper portion 5 of the crosshead through the crosshead sliding gap 6 is suppressed, and the amount of oil intrusion becomes minute.

Next, another embodiment will be described. In the embodiment shown in FIG. 4, the oil adsorption filter 12 is provided in the intermediate portion between the piston 26 and the crosshead 24 so as to be held on the cylinder 9 side. According to such an embodiment, a small amount of the lubricating oil mist that has entered the upper space 5 of the crosshead is adsorbed by the oil adsorption filter 12, and an oil intrusion prevention structure with higher performance can be realized.

FIG. 5A shows a case where the piston ring 11 is not attached to the crosshead 24 and a lubricating oil held in the crosshead gap 6 has a sealing function. Further, FIG. 5 (b) shows an embodiment in which the outer diameter of the upper end surface of the crosshead 24 is slightly smaller and a storage portion for the lubricating oil 13 is provided, whereby the lubricating oil is not stored on the upper plane of the crosshead. It is possible to suppress the upward scattering of the lubricating oil. This type can also be adopted in a crosshead to which the piston ring 11 is attached.

FIG. 6 shows an embodiment in which the oil adsorbing filter 14 is fixed with a narrow gap that does not contact the piston rod 25. In this embodiment, it is possible to eliminate the decrease in oil pump up caused by the contact between the piston rod 25 and the oil adsorption filter 14.

The oil separator 2 in each of the above-mentioned embodiments does not need to be installed in the middle of the communication pipe 1, and for example, the crankcase 21
It may be provided inside. Also, the type of piston ring 11,
The material is not specified.

〔The invention's effect〕

As described above, according to the present invention, the upper and lower spaces of the crosshead are communicated with each other via the check valve, the oil separator, etc., and the crosshead upper space average pressure is set higher than the lower space pressure. This has the effect of suppressing the amount of lubricating oil scattered above the crosshead. Further, if an oil adsorption filter is provided in the upper space of the crosshead, the effect of preventing oil scattering can be further improved, and lubricating oil can be prevented from entering the compression chamber and the working space.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an oil intrusion prevention structure according to an embodiment of the present invention, FIGS. 2 and 3 are views showing pressure conditions during operation of an engine in a space above and below a crosshead, and FIGS. 6
FIG. 7 is a schematic sectional view showing another embodiment of the present invention, and FIGS. 7 to 9 are schematic sectional views showing a conventional oil intrusion prevention structure. 1 ... Communication pipe, 2 ... Oil separator, 3 ... Check valve, 4 ... Crankcase inner space, 5 ... Crosshead upper space, 9 ... Cylinder, 10 ... Oil droplets, 11 ... Piston ring, 21 ... Crankcase , 22 ... crankshaft, 23 ... connecting rod, 24 ... crosshead, 25 ... piston rod, 26 ... piston, 29 ... compression space. The same reference numerals in the drawings indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michio Fujiwara 8-1-1 Tsukaguchihonmachi, Amagasaki City, Hyogo Prefecture Sanryo Electric Co., Ltd. Central Research Laboratory (72) Inventor Tetsuya Honda 8-chome, Tsukaguchihonmachi, Amagasaki City, Hyogo Prefecture No. 1 in Central Research Laboratory, Sanryo Electric Co., Ltd. (56) Reference JP-A-51-25678 (JP, A)

Claims (6)

[Claims] Claims: 1. A crankcase pressurizing type unlubricated compressor having a crankshaft, a connecting rod, a crosshead, and a piston for converting a rotary motion into a reciprocating motion, and an oil intrusion prevention structure in a heat engine. Even when the head and the piston are reciprocating, the intermediate space between the upper part of the crosshead and the piston is configured so that the volume does not change, or the change rate thereof is very small, and the crankcase under the crosshead is configured. The inner space and the upper space of the crosshead are communicated with each other via a check valve whose upper part is in the flow direction from the lower part of the crosshead, and the inner space and the upper space of the crosshead are connected to each other through a check valve. An oil intrusion prevention structure characterized by being provided with an oil separator for separating lubricating oil. 2. The oil intrusion prevention structure according to claim 1, wherein a piston ring is attached to the crosshead. 3. An oil adsorption filter is fixedly provided on the cylinder side in an intermediate space between the piston and the upper portion of the crosshead, and the oil adsorption filter is provided on the cylinder side. Oil intrusion prevention structure. 4. The oil adsorption filter is mounted with a gap between an inner peripheral surface thereof and a piston rod connecting the crosshead and the piston. Oil intrusion prevention structure according to item 3. 5. The oil separator is provided in the middle of a communication passage that connects the internal space of the crankcase and the upper space of the crosshead.
The oil intrusion prevention structure according to any one of items 1 to 4. 6. The oil intrusion prevention structure according to any one of claims 1 to 4, wherein the oil separator is provided in the crankcase.