JP7043038B2 - Air compressor - Google Patents

Description

The present invention relates to a reciprocating air compressor, and more particularly to a technique for improving the lubricating oil (oil) so as not to be mixed in the discharged air from the air compressor.

In the conventional reciprocating air compressor of this type, the inside of the crankcase is used as a lubricating chamber to supply lubricating oil to the bearing part of the crankshaft, the connecting part with the connecting rod, and the sliding surface between the piston and the cylinder. It is configured as follows.
However, in this lubricating structure, it is unavoidable that the lubricating oil rises to the compression chamber, so that the lubricating oil is mixed in the discharged air and contaminates the filter of the air dryer of the rear system, and further, the air dryer. Since oil is also contained in the air discharged from the air to the outside, it adversely affects the surrounding environment.
Therefore, in order to prevent the lubricating oil from being mixed into the discharged air, a partition plate is provided between the crankcase and the cylinder, and an oil seal is provided between the partition plate and the connecting rod above the piston. An air compressor has been proposed to prevent the infiltration of lubricating oil into the compression chamber formed in (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 10-10345

However, the air compressor in Patent Document 1 described above has a problem that a large modification of the crank mechanism is unavoidable in order to reduce the lateral load applied to the oil seal.

An object of the present invention is to provide an air compressor capable of preventing lubricating oil from being mixed into the discharged air without modifying the crank mechanism.

Typical means for solving the above-mentioned problems are as follows.
The crankcase containing the lubricating oil, the crankshaft supported in the crankcase, the cylinder provided in the crankcase, and the liner of the cylinder are reciprocally fitted and reciprocated by the crankshaft. An air compressor comprising a piston, a cylinder head arranged on the opposite side of the cylinder to the crankcase, and a suction valve and a discharge valve provided on the cylinder head.
The piston is provided with a cylinder hole, a piston pillar is provided at a position of the cylinder head facing the cylinder hole, and the piston pillar is slidably fitted into the cylinder hole. The liner is provided with a communication passage that communicates inside and outside the gap formed between the outer peripheral surface of the pillar and the inner peripheral surface of the liner.
An air compressor characterized by that.

According to the present invention, it is possible to prevent the lubricating oil from being mixed into the discharged air without modifying the crank mechanism of the air compressor.

It is a vertical sectional view which shows the intake end state of the air compressor which is 1st Embodiment of this invention. It is a vertical sectional view which shows the exhaust end state of the air compressor which is 1st Embodiment of this invention. It is a vertical sectional view which shows the intake end state of the air compressor which is the 2nd Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

1 and 2 show the first embodiment.
In the present embodiment, the air compressor according to the present invention is configured to be mounted on a vehicle.
The air compressor 1 according to the present embodiment includes a cylinder 10, a piston 20 reciprocally arranged in the cylinder 10, and a cylinder head 30 arranged in the upper part of the cylinder 10.
A crankcase 11 is formed at one end of the cylinder 10 (hereinafter referred to as a lower end), and a crankshaft 12 is rotatably supported in the crankcase 11 by a pair of bearings 13 and 13. The lower end of the connecting rod 14 is rotatably connected to the middle portion of the crankshaft 12, and the piston pin 15 of the piston 20 is rotatably connected to the upper end of the connecting rod 14.
A predetermined amount of lubricating oil is supplied and stored in the crankcase 11 from a fuel filler port (not shown), and the bearings 13 and 13 of the crankshaft 12, the connecting portion between the crankshaft 12 and the connecting rod 14 and the connecting rod 14 are stored. The connecting portion between the rod 14 and the piston pin 15 is oil-lubricated.
One end of the crankshaft 12 projects outside the crankcase 11, and a connecting portion 16 is formed at the protruding end. The crankshaft 12 is rotationally driven by connecting the rotation shaft (not shown) on the engine side to the connection portion 16 via, for example, a key.

A liner 17 is formed in a cylindrical shape on the upper portion of the cylinder 10, and a piston 20 is slidably fitted in the liner 17. An oil seal 18 is provided on the inner peripheral surface of the intermediate portion of the liner 17, and the inner peripheral surface of the oil seal 18 is slidably contacted with the outer peripheral surface of the upper end portion of the piston 20. An oil ring 19 is provided on the outer peripheral surface of the lower end portion of the piston 20, and the outer peripheral surface of the oil ring 19 is slidably contacted with the inner peripheral surface of the lower end portion of the liner 17.

A pin hole 21 is provided at the lower end of the piston 20 so as to be orthogonal to the connecting rod 14, and a piston pin 15 is fitted in the pin hole 21 and is prevented from coming off by a pair of stopper rings 22 and 22. The piston pin 15 is formed in a cylindrical shape, and both ends of the pin hole 21 and the hollow portion of the piston pin 15 communicate with each other in the liner 17.
A connecting portion of the connecting rod 14 is rotatably fitted to the piston pin 15. The contact surface between the pin hole 21 and the piston pin 15 and the contact surface between the piston pin 15 and the connecting rod 14 are lubricated by the lubricating oil supplied from the oil supply port (not shown) of the crankcase 11. Lubricating oil is also supplied from the inside of the crankcase 11 and the pin hole 21 to the sliding surface between the liner 17 and the piston 20.

The cylinder head 30 is placed over the upper end opening of the cylinder 10 and is positioned by the inro coupling portion 40, and is fastened by a fastening means (not shown) such as a bolt.
The cylinder head 30 is provided with a suction path 31 and a discharge path 32, respectively. The intake passage 31 is connected to the air cleaner via the engine intake pipe, and the discharge passage 32 is connected to the reservoir via a check valve and an air dryer.
A valve plate (valve plate) 33 and a reed valve 34 for a suction valve are superposed on the lower end surface of the cylinder head 30 and fastened by a fastening means (not shown) such as a bolt. A suction port 36 is opened at a position facing the suction path 31 of the valve plate 33, and the suction port 36 is opened and closed by a suction valve 37 formed in the reed valve 34. A discharge port 38 is provided at a position of the valve plate 33 facing the discharge path 32, and the discharge port 38 is opened and closed by the discharge valve 39.

A cylinder hole 25 is embedded in a cylindrical hole shape on the upper end surface of the piston 20, and a piston column 41 is projected in a cylindrical shape at a position facing the cylinder hole 25 of the cylinder head 30. The piston column 41 is slidably fitted in the cylinder hole 25, and reciprocates relatively in the cylinder hole 25 as the piston 20 reciprocates. Since the air is compressed by the reciprocating motion of the piston column 41 in the cylinder hole 25, the cylinder hole 25 and the piston column 41 form a compression chamber 42.
The valve plate 33 is arranged at the lower end of the piston column 41 and is formed to have the same diameter, and a pressure ring 43 is fixed to the outer periphery thereof. The outer peripheral surface of the pressure ring 43 is slidably contacted with the inner peripheral surface of the upper end portion of the cylinder hole 25.

A gap 44 having a width corresponding to the thickness of the side wall of the cylinder hole 25 is formed between the outer peripheral surface of the piston column 41 and the inner peripheral surface of the upper end portion of the liner 17, and the gap 44 is formed with the side wall of the cylinder hole 25. Reciprocates following the reciprocating motion of the piston 20 with respect to the liner 17, that is, the reciprocating motion of the piston column 41 with respect to the cylinder hole 25.
A communication passage 45 is provided at the upper end of the liner 17 so as to communicate inside and outside the gap 44, and the communication passage 45 allows the volume change of the gap 44 due to the reciprocating movement of the side wall of the cylinder hole 25. A filter 46 that allows only air flow is installed in the communication passage 45. That is, the filter 46 prevents dust and water droplets from entering the gap 44 from the engine room, and allows air to enter and exit the gap 44.

Next, the operation of the air compressor 1 will be described.

When the crankshaft 12 is rotationally driven by an engine or the like, the piston 20 reciprocates in the liner 17 via the connecting rod 14. When the piston 20 reciprocates in the liner 17, the volume change of the gap 44 is allowed by the communication passage 45, so that the piston column 41 projecting from the cylinder head 30 is inside the cylinder hole 25 embedded in the piston 20. Reciprocates relatively.
Due to the action of the suction valve 37 and the discharge valve 39 accompanying the reciprocating movement in the cylinder hole 25 of the piston column 41, the compression action is performed in the compression chamber 42, and the discharge air compressed to a predetermined pressure is discharged from the discharge port 38. Will be done.
By the way, the pressure ring 43 prevents the pressure from leaking from the compression chamber 42.
Further, the filter 46 prevents dust and water droplets from entering the gap 44 from the engine room.

During the compression operation of the air compressor 1, the bearings 13 and 13 of the crankshaft 12 and the sliding surfaces of the liner 17 and the piston 20 are oil-lubricated by the splashing action of the lubricating oil accompanying the rotation of the crankshaft 12. Further, each contact surface of the pin hole 21, the piston pin 15, and the connecting rod 14 is lubricated by the lubricating oil supplied from the oil supply port (not shown) provided in the crankcase 11. These oil lubrications prevent the occurrence of troubles such as seizure during the operation of the air compressor 1.

At this time, since the compression chamber 42 formed by the cylinder hole 25 and the piston column 41 is isolated from the inside of the crankcase 11 via the gap 44 between the liner portion 17 and the piston column 41, the lubricating oil and the crank The phenomenon that the so-called oil mist generated in the case 11 invades the compression chamber 42 is suppressed.
Therefore, it is possible to prevent lubricating oil and oil mist from being mixed in the discharged air discharged from the discharge port 38.
Incidentally, the lubricating oil adhering to the outer peripheral surface of the piston 20 is scraped off by the oil seal 18. The scraped off lubricating oil returns to the inside of the crankcase 11 through the clearance between the liner 17 and the piston 20.

According to this embodiment, the following effects can be obtained.

(1) During the compression operation of the air compressor 1, the sliding surfaces of the bearings 13, 13 and the liner 17 of the crankshaft 12 and the piston 20 and the contact surfaces of the pin hole 21, the piston pin 15, and the connecting rod 14 are oiled. Since it is lubricated, it is possible to prevent the occurrence of seizure or the like during the operation of the air compressor 1.

(2) Since the compression chamber 42 formed by the cylinder hole 25 and the piston column 41 is isolated from the inside of the crankcase 11 via the gap 44 between the liner portion 17 and the piston column 41, the lubricating oil and the crank It is possible to prevent the so-called oil mist generated in the case 11 from entering the compression chamber 42.

(3) By preventing the lubricating oil and the so-called oil mist generated in the crank case 11 from entering the compression chamber 42, the lubricating oil and the oil mist are mixed in the discharge air discharged from the discharge port 38. Not only can it be avoided, but it is also possible to prevent the generation of carbonization due to contact of the lubricating oil or oil mist with the high-temperature compressed air.

(4) By coupling the cylinder head 30 to the liner 17, the clearance between the cylinder hole 25 and the piston column 41 can be easily and appropriately managed.

(5) By providing the pressure ring 43 that is in sliding contact with the inner peripheral surface of the cylinder hole 25 on the outer peripheral surface of the piston 20, it is possible to prevent the pressure from leaking from the compression chamber 42.

(6) By returning the lubricating oil scraped off by the oil seal 18 to the inside of the crankcase 11 through the clearance between the liner 17 and the piston 20, it is possible to prevent the lubricating oil from decreasing.

(7) By eliminating the piston ring on the outer peripheral surface of the piston 20, the factors that scoop up the lubricating oil can be reduced, so that the intrusion of the lubricating oil and the oil mist into the compression chamber 42 can be further suppressed. ..

(8) By installing the filter 46 in the communication passage 45, it is possible to prevent dust and water droplets from entering the gap 44 from the engine room.

(9) Since the oil lubrication part and the compression chamber are separated, the compression chamber is freed from the design problem of the sliding structure between the liner and the piston, and the sliding part (cylinder hole and piston column) in the compression chamber. The degree of freedom in oilless design of the facing surface) can be increased, and the resinification of parts such as liners, pistons and cylinder heads and the expansion of the choice of coating materials for sliding surfaces can be promoted.

(10) Since it is not necessary to provide an oil seal between the partition plate between the crankcase and the cylinder and the partition plate and the connecting rod, it is possible to avoid modification of the crank mechanism of the air compressor.

FIG. 3 shows a second embodiment of the present invention.
The difference between this embodiment and the first embodiment is that the drain 51 is provided at the upper position of the oil seal 18 in the liner 17 so as to communicate the inside and outside, and the drain device 52 is connected to the drain 51. The drain device 52 is provided with a discharge path 53 connecting the drain 51 and the inside of the crankcase 11, a buffer 54 interposed in the drain path 53, and a direction switching valve 55.
The directional control valve 55 is always closed, is opened by the solenoid after a preset time has elapsed after the engine is stopped, and is closed by the solenoid after a preset time has elapsed after being opened. Lubricating oil collects in the buffer 54 while the discharge path 53 is closed by the directional control valve 55, and the lubricating oil is returned from the buffer 54 into the crankcase 11 when the directional control valve 55 is opened.
According to the present embodiment, in addition to the effect of the first embodiment, the effect that the decrease of the lubricating oil can be further suppressed can be obtained.

Needless to say, the present invention is not limited to the above embodiment, and various changes can be made without departing from the gist thereof.

The discharge path of the drain device is not limited to being connected to the inside of the crankcase, but may be connected to a lubrication pipe for circulating lubricating oil.

The directional control valve of the drain device is not limited to the solenoid type, but may be configured as a pilot type or a manual type.

The intake valve and the discharge valve are not limited to the reed valve, but may be composed of a disc valve or the like.

In the above embodiment, the air compressor mounted on the vehicle has been described, but the present invention is not limited to this, and can be applied to all air compressors used for other purposes.

1 ... Air compressor, 10 ... Cylinder, 11 ... Crankcase, 12 ... Crankshaft, 13 ... Bearing, 14 ... Connecting rod, 15 ... Piston pin, 16 ... Connection part, 17 ... Liner part, 18 ... Oil seal, 19 ... Oil ring,
20 ... piston, 21 ... pin hole, 22 ... stopper ring, 25 ... cylinder hole,
30 ... Cylinder head, 31 ... Suction path, 32 ... Discharge path, 33 ... Valve plate (valve plate), 34 ... Suction valve reed valve, 36 ... Suction port, 37 ... Suction valve, 38 ... Discharge port, 39 ... Discharge valve,
40 ... Inro joint, 41 ... Piston pillar, 42 ... Compression chamber, 43 ... Pressure, 44 ... Gap, 45 ... Communication passage, 46 ... Filter,
51 ... Drain, 52 ... Drain device, 53 ... Discharge path, 54 ... Buffer, 55 ... Direction switching valve.

Claims (5)

The crankcase containing the lubricating oil, the crankshaft supported in the crankcase, the cylinder provided in the crankcase, and the liner of the cylinder are reciprocally fitted and reciprocated by the crankshaft. An air compressor comprising a piston, a cylinder head arranged on the opposite side of the cylinder to the crankcase, and a suction valve and a discharge valve provided on the cylinder head.
The piston is provided with a cylinder hole, a piston pillar is provided at a position of the cylinder head facing the cylinder hole, and the piston pillar is slidably fitted into the cylinder hole. The liner is provided with a communication passage that communicates inside and outside the gap formed between the outer peripheral surface of the pillar and the inner peripheral surface of the liner.
An air compressor characterized by that. A filter that allows only air flow is installed in the passageway.
The air compressor according to claim 1. An oil seal is provided on the inner peripheral surface of the intermediate portion of the liner, and the inner peripheral surface of the oil seal is slidably contacted with the outer peripheral surface of the piston.
The air compressor according to claim 1 or 2. An oil ring is provided on the outer peripheral surface of the piston, and the outer peripheral surface of the oil ring is slidably contacted with the inner peripheral surface of the liner.
The air compressor according to claim 1, 2 or 3. A drain is provided in the liner so as to communicate inside and outside, and a drain device for returning the lubricating oil to the crankcase is connected to the drain.
The air compressor according to claim 1, 2, 3 or 4.

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