JP2000291544A - Air compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively cool a bearing inside a piston. SOLUTION: This air compressor 10 that is an oilless type (an unlubricated type) reciprocation compressor has a piston 11 and a cylinder 12. A crankshaft is installed with a vane plate 25 for generating an airflow cooling the inside of the piston 11 in a crank chamber. The vane plate 25 is installed on the periphery of the crankshaft, such that the vane plate 25 extends parallel to the radial direction, while a front end 25a of the vane plate 25 rotates with a phase difference of 180 degrees to reciprocation of the piston 11. When the piston 11 moves to the bottom dead center, the vane plate 25 installed on the periphery of the crankshaft rotates together with the rotation of the crankshaft and presses air in the crank chamber in the rotating direction to generate airflow. Accordingly, when the piston 11 moves down to the bottom dead center, cooling air is supplied inside the piston 11 to further improve cooling efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an air compressor,
In particular, the present invention relates to an air compressor configured to convert rotational motion of a crankshaft into reciprocating motion of a piston via a connecting rod connected to the piston.

[0002]

2. Description of the Related Art As an air compressor, there is a reciprocating compressor which sucks, compresses and discharges air by reciprocating pistons. This type of reciprocating compressor includes a cylinder in which a piston reciprocates, a cylinder head having a suction passage and a discharge passage, and a valve seat member interposed between the cylinder and the cylinder head. The valve seat member is formed in a flat plate shape, and is provided with a suction port communicating with the suction passage and a discharge port communicating with the discharge passage. A suction valve seat for opening and closing the suction port, and a suction valve plate that detaches and seats on the suction valve seat in accordance with the reciprocating operation of the piston are mounted on the lower surface side of the valve seat member. Also, on the upper surface side of the valve seat member, a discharge valve seat for opening and closing the discharge port,
A discharge valve plate is attached and detached from the discharge valve seat according to the reciprocating motion of the piston.

[0003] A small end of a connecting rod is connected to the piston, and a large end of the connecting rod is connected to an eccentric shaft of a crankshaft. Therefore, when the crankshaft is rotationally driven by the motor, the piston reciprocates while the connecting rod swings. The suction valve plate and the discharge valve plate open and close according to the direction of operation of the piston, so that each time the piston reciprocates in the cylinder, compressed air is discharged from the discharge port to the discharge passage and the pressure in the air tank rises. I do.

There are two types of air compressors: an oilless type (oilless type) and an oil lubrication type. In the case of the oilless type, since lubricating oil is not supplied, it is necessary to radiate frictional heat in each operation part to the outside. Therefore, in an oilless air compressor, the cylinder is cooled from the outside, thereby indirectly cooling the piston that reciprocates inside the cylinder, and the heat generated by the reciprocation of the piston generates heat from the small end of the connecting rod. A configuration is adopted in which heat is dissipated through a cylinder so that the portion is not transmitted to a bearing to which the portion is connected.

[0005]

However, in the conventional air compressor, the cylinder is externally cooled to indirectly cool the temperature of the bearing to which the piston and the small end of the connecting rod are connected as described above. The method alone has structural limitations on cooling the bearing inside the piston and heat insulation of the bearing to which the piston pin fits, and requires durability, high reliability,
It is difficult to cope with an increase in bearing temperature due to an increase in pressure or the like.

Further, in order to prevent the heat accompanying the reciprocating motion of the piston from being transmitted to the bearing of the piston pin, a heat insulating material is provided on the piston pin to reduce heat conduction to the bearing and suppress a rise in the temperature of the bearing. However, since a compressive load at the time of air compression is applied to the piston pin periodically, settling of the heat-insulating material affects the service life and is an obstacle to improvement of durability and pressure reduction.

Therefore, an object of the present invention is to provide an air compressor which has solved the above-mentioned problems.

[0008]

In order to solve the above problems, the present invention has the following features. Claim 1
The described invention is an air compressor in which a connecting rod connected to a piston reciprocates the piston by rotation of a crankshaft, and when the piston reaches a bottom dead center, approaches a lower end of the piston An air flow generating member that is provided on the crankshaft so as to move to a position, and that generates an air flow for cooling a bearing of a piston pin traversed by the piston. .

Therefore, according to the first aspect of the present invention, when the piston reaches the bottom dead center, the airflow generating member provided on the crankshaft so as to move to a position approaching the lower end of the piston is provided by the piston. A small end of a connecting rod that supplies airflow to the inside of the piston to the bottom dead center and bears the piston pin inside the piston in order to generate an airflow for cooling the bearing of the piston pin that is laid horizontally The bearings of the part can be cooled effectively.

According to a second aspect of the present invention, in the air compressor according to the first aspect, a guide portion for guiding the air flow generated by the air flow generating member into the piston is provided on the connecting rod. It is characterized by having. Therefore, according to the second aspect of the present invention, the guide portion for guiding the air flow generated by the air flow generating member into the piston is provided on the connecting rod, so that the air flow flows along the guide portion inside the piston. The inside of the piston can be efficiently cooled by being guided.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of an embodiment of the air compressor according to the present invention. FIG. 2 shows A-
It is a longitudinal cross-sectional view which follows the A line. As shown in FIGS. 1 and 2, the air compressor 10 is of an oilless type (oilless type).
, A cylinder 12 in which a piston 11 reciprocates, a cylinder head 13 provided with a suction passage and a discharge passage, and a suction valve and a discharge valve provided between the cylinder 12 and the cylinder head 13. Interposed valve seat member 1
And 4. Further, the cylinder 12 is mounted on an upper part of the crankcase 15.
Is rotatably supported in a state in which a crankshaft 16 is inserted.

The crankshaft 16 is supported at both ends by bearings 17 and 18 held on the wall of the crankcase 15, and includes a crank arm 19 and bearings 17 and 18.
And an eccentric shaft 20 eccentric in the radial direction. The rear end 21 of the crankshaft 16 is connected to the crankcase 1.
5, and a driving pulley 22 is fitted and fixed. The drive pulley 22 is wound around a belt (not shown) for transmitting a rotational driving force from a drive motor (not shown).

The eccentric shaft 20 of the crankshaft 16 and the piston 1
1 is connected via a connecting rod 23. The connecting rod 23 has an upper small end 23 a fitted to a piston pin 24 laid horizontally inside the piston 11, and a lower large end 23 b fitted to the eccentric shaft 20 of the crankshaft 16. Therefore, when the crankshaft 16 is rotationally driven by the driving motor, the connecting rod 23 swings while the piston 1
1 is reciprocated.

As described above, the reciprocating movement of the piston 11 causes the suction valve and the discharge valve provided on the valve seat member 14 to open or close, thereby performing a process of sucking outside air, a process of compressing air, and a process of discharging air. The steps are performed sequentially. The crankshaft 16 is provided with a blade 25 serving as an airflow generating member for generating an airflow for cooling the inside of the piston 11 in a crank chamber 15 a formed in the crankcase 15. The blade plate 25 is attached to the outer periphery of the crankshaft 16 so as to extend in a direction parallel to the radial direction.
It rotates with a phase difference of 80 °.

FIG. 3 is a longitudinal sectional view showing an operation state in which the piston 11 has moved to the bottom dead center. Also, FIG.
It is a longitudinal cross-sectional view which follows the B line. As shown in FIGS. 3 and 4, when the piston 11 moves to the bottom dead center, the blade plate 25 attached to the outer periphery of the crankshaft 16 rotates while the crankshaft 16 rotates, and the air in the crank chamber 15 a rotates. Is pressed in the direction of rotation to generate an airflow. Therefore, when the piston 11 is reciprocating, the air in the crank chamber 15 a always convects in the rotation direction of the blade plate 25 due to the rotation of the blade plate 25.

When the piston 11 is at the top dead center as shown in FIG. 1 and FIG.
a faces downward of the crank chamber 15a, and as shown in FIGS. 3 and 4, when the piston 11 is at the bottom dead center, the tip 25a faces upward of the crank chamber 15a. Therefore, when the piston 11 reaches the bottom dead center, the tip 25a of the blade plate 25 comes closest to the piston 11, and the airflow in the crank chamber 15a is forcibly supplied to the inside of the piston 11. Thereby, the bearing 23c in which the piston pin 24 provided inside the piston 11 is fitted is effectively cooled.

FIG. 5A is a front view showing the structure of the connecting rod 23. As shown in FIG. FIG. 5B is a left side view showing the configuration of the connecting rod 23. As shown in FIGS. 5A and 5B,
A guide plate 26 that guides the air flow generated by the rotation of the blade plate 25 to a bearing 23c provided inside the piston 11 is attached to the left side surface 23d of the connecting rod 23. The guide plate 26 is made of a flat metal plate, and has a connecting rod 23.
Are fixed to the left side surface 23 d of the connecting rod 23 by mounting bolts 27 in a direction extending in the longitudinal direction of the connecting rod 23. In the present embodiment, in FIGS. 1 and 3, the crankshaft 16 rotates clockwise.

The guide plate 26 is attached to the left side surface 23d of the connecting rod 23 on the opposite side to the rotation direction. Therefore, the air flow in the crank chamber 15a generated by the rotation of the blade plate 25 flows upward along the guide plate 26 as indicated by the arrow in FIG. as a result,
When the piston 11 descends to the bottom dead center, cooling air is supplied to the inside of the piston 11, and the cooling efficiency is further improved.

Therefore, the life of the air compressor 10 can be extended, and the durability can be improved.
Therefore, it is possible to suppress an increase in bearing temperature due to improvements in durability, high reliability, high pressure, and the like required from the market, and to enhance the performance of the oilless (no oiling) air compressor 10. . When the piston 11 moves to the bottom dead center, the blade plate 25 comes closest to the guide plate 26 attached to the left side surface 23d of the connecting rod 23, but as shown in FIG. Since they are offset in the axial direction of the shaft 16, there is no interference.

FIG. 6 is a front view showing the configuration of the crankshaft 16. FIG. 7 is an enlarged front view showing a mounting portion of the blade plate 25. As shown in FIG. 6 and FIG. 7, the blade plate 25 extends 180 ° from the eccentric shaft 20 with respect to a straight line C connecting the shafts 16 a and 16 b at both ends where the tip 25 a is the rotation center of the crankshaft 16. It is attached to be. This allows the tip 25a of the blade plate 25 to move upward when the piston 11 descends to the bottom dead center and to come closest to the guide plate 26 of the connecting rod 23.

The blade plate 25 includes a pair of mounting bolts 2.
8 is fixed to the outer periphery of the crankshaft 16. FIG.
FIG. 5 is a longitudinal sectional view for explaining a mounting structure of a blade plate 25. As shown in FIG. 8, a mounting surface 29 for fixing the blade plate 25 is provided on the outer periphery of the crankshaft 16. Further, bolt insertion holes 30 and 31 are provided to pass through the crankshaft 16 from the mounting surface 29 in the horizontal direction. The other ends of the bolt insertion holes 30 and 31 are open to a flat surface 32 formed on the opposite side of the outer periphery of the crankshaft 16.

The mounting bolt 28 is attached to the base end 25 of the slat 25.
After being inserted into the hole 25c provided on the b side, it is inserted into the bolt insertion holes 30, 31. A washer 33 and a nut 34 are attached to the tip of the mounting bolt 28 protruding toward the flat surface 32.
And the nut 34 is tightened. Thus, the mounting bolt 28 is fastened to the crankshaft 16 by the nut 34 and fixes the blade plate 25 to the mounting surface 29.

As described above, the mounting direction of the blade plate 25 by contacting the mounting surface 29 is determined.
A stable state is maintained by the pair of mounting bolts 28. FIG. 9 is a longitudinal sectional view for explaining a modification of the mounting structure of the blade plate 25. FIG. 10 is a right side view of a modified example of the mounting structure shown in FIG. As shown in FIGS. 9 and 10, on the outer periphery of the crankshaft 16, a mounting portion 36 for locking the blade plate 25 projects rightward. This mounting portion 36 is formed in a square shape when viewed from the right side, and has bolt insertion holes 36a (in FIG. 10,
(Indicated by a broken line) penetrates.

On the other hand, the blade plate 25 is provided with a bracket 37 on the left side of the base end 25b and abutting on the left side surface of the mounting portion 36, and a bracket 38 on the right side of the base end 25b and abutting on the right side surface of the mounting portion 36. ing. And the mounting bolt 39
Are inserted into the bolt insertion holes 36 a of the brackets 37 and 38 and the mounting portion 36, and the nut 40 is screwed on the bracket 37 side. Therefore, when the nut 40 is tightened, the mounting bolt 39 and the nut 40 are
7 and 38 are sandwiched from both sides and pressed against the left and right side surfaces of the mounting portion 36.

Thus, the blade plate 25 is positioned such that the base end 25b is fixed to the mounting portion 36 of the crankshaft 16 and the tip end 25a extends in the direction of 180 ° with the eccentric shaft 20. Is done. In the above embodiment, the guide plate 26 is attached to the connecting rod 23.
6 and the piston 1
1 can be cooled.

[0026]

As described above, according to the first aspect of the present invention, when the piston reaches the bottom dead center, the air flow generated on the crankshaft is moved to a position approaching the lower end of the piston. A member that supplies airflow to the inside of the piston to the bottom dead center and generates a flow of air to cool the bearing of the piston pin that is traversed by the piston. The bearing at the small end of the rod can be effectively cooled. Therefore, the life of the air compressor can be extended, and the durability can be improved. Therefore, it is possible to suppress an increase in bearing temperature due to improvements in durability, high reliability, high pressure, and the like required from the market, and it is possible to enhance the performance of an oilless (non-lubricating) air compressor.

According to the second aspect of the present invention, since the connecting rod is provided with a guide portion for guiding the air flow generated by the air flow generating member into the piston, the air flow is generated along the guide portion by the piston. And the inside of the piston can be efficiently cooled.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of an air compressor according to the present invention.

FIG. 2 is a longitudinal sectional view taken along line AA in FIG.

FIG. 3 is a longitudinal sectional view showing an operation state in which a piston 11 has moved to a bottom dead center.

FIG. 4 is a longitudinal sectional view taken along line BB in FIG.

FIG. 5 is a diagram showing a configuration of a connecting rod 23.

FIG. 6 is a front view showing a configuration of a crankshaft 16;

FIG. 7 is an enlarged front view showing a mounting portion of the blade plate 25;

FIG. 8 is a longitudinal sectional view for explaining a mounting structure of the blade plate 25.

FIG. 9 is a longitudinal sectional view for explaining a modification of the mounting structure of the blade plate 25.

FIG. 10 is a right side view of a modified example of the mounting structure shown in FIG.

[Explanation of symbols]

 Reference Signs List 10 air compressor 11 piston 12 cylinder 13 cylinder head 14 valve seat member 15 crankcase 15a crank chamber 16 crankshaft 19 crank arm 20 eccentric shaft 22 driving pulley 23 connecting rod 23a small end 23b large end 24 piston pin 23c, 23d Bearing part 25 Blade plate 26 Guide plate 27, 28, 39 Mounting bolt 29 Mounting surface 30, 31 Bolt insertion hole 36 Mounting part 37, 38 Bracket

Claims (2)

[Claims] 1. An air compressor in which a connecting rod connected to a piston reciprocates the piston by rotation of a crankshaft, wherein the piston approaches a lower end of the piston when the piston reaches a bottom dead center. An air flow generating member provided on the crankshaft so as to move to a position, and for generating an air flow for cooling a bearing of a piston pin traversed by the piston. . 2. The air compressor according to claim 1, wherein a guide portion for guiding an air flow generated by the air flow generation member into the piston is provided on the connecting rod. Compressor.