JP2016114070A - air compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To materialize an air compressor which can easily and certainly supply a proper amount of a lubricant to a bearing interposed between a connecting rod and a piston.SOLUTION: An air compressor has a hollow piston pin 80 which couples pistons 52a, 52b and connecting rods 53a and 53b; a needle bearing 81 interposed between the pistons 52a and 52b and the connecting rods 53a and 53b; and a through-hole 82 which communicates an inner space 83 of the piston pin 80 and the needle bearing 81. When a container 91 filled with a lubricant 90 is inserted in the inside of the piston pin 80, a projecting portion 97 formed on the container 91 is fitted with the through-hole 82 to position the container 91. If the capacity of the positioned container 91 is decreased, the lubricant 90 is extruded through a communication hole formed on the projecting portion 97, and supplied to the needle bearing 81 through the through-hole 82.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an air compressor, and more particularly to a reciprocating type air compressor.

  A reciprocating type air compressor includes a power source, a piston that is reciprocated by a driving force output from the power source, a cylinder that accommodates the piston so as to reciprocate, and a volume that changes as the piston reciprocates. ,including. An electric motor may be used as the power source. In this case, the rotational driving force output from the electric motor is converted into a reciprocating driving force by a conversion mechanism including a connecting rod and transmitted to the piston.

  When the piston in the cylinder moves from the top dead center to the bottom dead center, the volume of the cylinder increases, the inside of the cylinder becomes negative pressure, and air is introduced into the cylinder. The air introduced into the cylinder is compressed by the piston moving from the bottom dead center to the top dead center in the cylinder, and the pressure is increased. The compressed air (high pressure air) is sent to an air tank via a predetermined pipe and stored in the air tank.

  A connecting rod (hereinafter referred to as a “connecting rod”) constituting the conversion mechanism and a piston are connected via a bearing so as to be relatively rotatable. In other words, the connecting rod can swing with respect to the piston. The connecting rod and the piston are connected via a needle bearing, for example. Furthermore, in an air compressor often used at a construction site or the like, an oil-free needle bearing is used in order to avoid intrusion of dust and the like. Both ends of the oil-free needle bearing are sealed with an oil seal and filled with a lubricant such as grease.

  However, during the operation of the air compressor, the connecting portion between the connecting rod and the piston becomes hot due to the compression heat. For this reason, the lubricant enclosed in the needle bearing is gradually vaporized, the lubricity is lowered, and the needle bearing may be seized.

  Therefore, a piston having a hollow piston pin to which a connecting rod is connected and having a lubricant filled in the piston pin has been proposed (Patent Document 1). That is, a piston is proposed in which the inner space of the piston pin is used as a container for the lubricant. In such a piston, a through hole is formed in the peripheral wall of the piston pin. Lubricant filled in the piston pin is sent out of the piston pin through the through hole and supplied to the needle bearing by vibration during operation of the air compressor.

JP 2006-125237 A

  However, the piston using the space inside the piston pin as a container for the lubricant has the following problems. When the amount of the lubricant filled in the piston pin is reduced, a gap is generated between the lubricant and the through hole, and the delivery of the lubricant becomes insufficient. Therefore, it is necessary to form a large number of through holes in the peripheral wall of the piston pin, resulting in an increase in manufacturing cost and a decrease in mechanical strength.

  Furthermore, since the supply amount of the lubricant cannot be controlled, more lubricant than necessary is supplied, and the leaked lubricant may adhere to the piston ring or the like. Lubricant adhering to a piston ring or the like contributes to poor pressure increase.

  An object of the present invention is to provide an air compressor capable of easily and reliably supplying an appropriate amount of lubricant to a bearing interposed between a connecting rod and a piston.

  The air compressor of the present invention is a reciprocating type air compressor that compresses air by a piston driven to reciprocate. The air compressor includes a cylinder that reciprocally accommodates the piston, a connecting rod that transmits a driving force to the piston, and a small end portion of the piston and the connecting rod, and the piston and the connecting rod. A hollow piston pin that connects the two, a bearing interposed between an inner peripheral surface of a connecting hole provided in the small end portion, and an outer peripheral surface of the piston pin that passes through the connecting hole, and the piston pin And a through hole that allows the inner space of the piston pin to communicate with the bearing. When a container filled with a lubricant is inserted inside the piston pin, a protrusion formed on the container is fitted into the through hole to position the container, and the volume of the positioned container Is reduced, the lubricant is pushed out through the communication hole formed in the protrusion and supplied to the bearing through the through hole.

  In one aspect of the present invention, when the container is pressed by a jig inserted inside the piston pin, the volume decreases due to plastic deformation.

  In another aspect of the present invention, the container includes a first jig inserted inside the piston pin from the one axial opening of the piston pin and the other axial opening of the piston pin. It is sandwiched and pressed between the second jig inserted inside the piston pin.

  In another aspect of the present invention, the container has a first end and a second end facing each other, at least the second end is movable, and the second end is moved to the first end. When moved in a direction closer to the end, the volume of the container decreases.

  In another aspect of the present invention, the container has a cylindrical main body, the first end is fixed to one end in the longitudinal direction of the main body, the second end is screwed to the main body, When the second end portion is rotated in a predetermined direction, the second end portion moves in a direction close to the first end portion.

  In another aspect of the present invention, the second end portion is movable to a position directly below the protrusion, and the second end reaching the position directly below the protrusion is a seal member that closes the communication hole.

  In another aspect of the present invention, after the lubricant is supplied to the bearing, the protrusion becomes a lid member that closes the through hole.

  ADVANTAGE OF THE INVENTION According to this invention, the air compressor which can supply an appropriate quantity of lubricants to the bearing interposed between a connecting rod and a piston easily and reliably is implement | achieved.

It is a perspective view of an air compressor. It is a perspective view of an air compressor in the state where a cover was removed. It is a horizontal sectional view of an air compressor. It is an expanded sectional view which shows the connection structure of a 1st connecting rod and a 1st piston. It is an expanded sectional view of a container. (A)-(f) is explanatory drawing which shows the procedure which supplies a lubricant to a needle bearing. (A) is an expanded sectional view which shows the modification of a container, (b) is an enlarged side view.

  Hereinafter, an example of an embodiment of an air compressor of the present invention is explained. The air compressor according to the present embodiment is a reciprocating type air compressor including a compressed air generation unit that uses a motor as a power source. The use of the air compressor according to the present embodiment is not particularly limited, but is suitable for use as a supply source for supplying compressed air to an air tool (for example, a nail driver) for driving a nail or a screw into wood by pressure of the compressed air. ing. Hereinafter, the air compressor according to the present embodiment will be described in detail with reference to the drawings.

  As shown in FIG. 1, an air compressor 1 according to the present embodiment includes a base 11 including a skeleton such as a frame and two parallel air tanks 10 a and 10 b connected to the skeleton. Have. Rubber legs 12 are attached to the lower surfaces of both end portions of each of the air tanks 10a, 10b, and the air compressor 1 is placed at a desired installation location by the four legs 12. Moreover, the handle | steering-wheel 13 is provided in the both ends of the base 11, and the operator can hold the handle | steering-wheel 13 and can carry the air compressor 1 in it.

  The base 11 is mounted with the motor 20 shown in FIG. 2 and a compressed air generation unit 30 using the motor 20 as a power source. Usually, the motor 20 and the compressed air generation unit 30 are covered with a cover 14 shown in FIG. Referring to FIG. 2 again, the compressed air generation unit 30 includes a crankcase 40 and two cylinders (a first cylinder 51a and a second cylinder 51b).

  As shown in FIG. 3, the motor 20 includes a stator (stator coil) 21, a rotor (rotor) 22 incorporated inside the stator 21, and a rotating shaft (motor rotation) fixed to the rotor 22. This is a DC brushless motor having a shaft 23 and a Hall element for detecting the rotational position of the rotor 22, and is disposed outside the crankcase 40. However, the motor 20 is fixed to one cover (first crankcase cover) of the crankcase 40 and integrated with the crankcase 40. The motor 20 in the present embodiment is an inner rotor type electric motor, but may be replaced with another type of motor, for example, an outer rotor type electric motor.

  The motor rotating shaft 23 passes through the crankcase 40 and is rotatably supported by a bearing provided in the crankcase 40. Specifically, the motor rotating shaft 23 passes through the first crankcase cover and the other cover (second crankcase cover) opposed to the first crankcase cover, and can be freely rotated by bearings provided in the respective covers. It is supported.

  A control circuit board 60 on which a semiconductor switching element for controlling the inverter of the motor 20 is mounted is disposed on the opposite side of the crankcase 40 from the motor 20. The control circuit board 60 is disposed so as to face the crankcase 40, and is fixed to the air tank 10b. A cooling fan 61 is disposed between the control circuit board 60 and the crankcase 40, and the control circuit board 60 is cooled by the cooling air generated by the cooling fan 61. The cooling fan 61 is fixed to one end of the motor rotating shaft 23 protruding from the second crankcase cover, and rotates integrally with the motor rotating shaft 23 to generate cooling air.

  A first cylinder 51 a and a second cylinder 51 b are attached to both sides of the crankcase 40. The first cylinder 51a and the second cylinder 51b are arranged at positions different by 180 degrees with respect to the rotation direction of the motor rotating shaft 23. The first piston 52a is accommodated in the first cylinder 51a so as to be able to reciprocate. A second piston 52b is accommodated in the cylinder 51b so as to reciprocate.

  In order to convert the rotational movement of the motor rotating shaft 23 into the reciprocating movement of the first piston 52a, one end of the first connecting rod 53a is pin-coupled to the first piston 52a, and the other end of the first connecting rod 53a. Is rotatably coupled to an eccentric cam mounted on the motor rotating shaft 23. That is, the first connecting rod 53a straddles the crankcase 40 and the first cylinder 51a and connects the motor rotating shaft 23 and the first piston 52a. Further, in order to convert the rotational movement of the motor rotating shaft 23 into the reciprocating movement of the second piston 52b, one end of the second connecting rod 53b is pin-coupled to the second piston 52b, and the second connecting rod 53b The other end is rotatably coupled to another eccentric cam mounted on the motor rotating shaft 23. That is, the second connecting rod 53b straddles the crankcase 40 and the second cylinder 51b and connects the motor rotating shaft 23 and the second piston 52b. In the following description, the motor rotating shaft 23 may be referred to as “crankshaft 23”. Further, the first connecting rod 53a may be referred to as “first connecting rod 53a”, and the second connecting rod 53b may be referred to as “second connecting rod 53b”.

  The rotational driving force output from the motor 20 is converted into a reciprocating driving force by a conversion mechanism including a crankshaft 23, an eccentric cam, and a connecting rod (first connecting rod 53a, second connecting rod 53b), and pistons (first piston 52a, first piston). 2 piston 52b).

  Here, the respective eccentric cams are eccentric in opposite directions with respect to the driving directions of the pistons 52a and 52b. Therefore, when the first piston 52a is driven in the direction of compressing the upper chamber of the first cylinder 51a, the second piston 52b is driven in the direction of expanding the upper chamber of the second cylinder 51b. On the other hand, when the second piston 52b is driven in the direction of compressing the upper chamber of the second cylinder 51b, the first piston 52a is driven in the direction of expanding the upper chamber of the first cylinder 51a. The upper chambers of the cylinders 51a and 51b are spaces above the pistons 52a and 52b in the cylinders 51a and 51b.

  Buffer chambers 55a and 55b are provided inside the cylinder heads 54a and 54b provided in the respective cylinders 51a and 51b, and between the upper chambers of the cylinders 51a and 51b and the buffer chambers 55a and 55b. Each has a check valve. When the first piston 52a is driven in a direction to compress the upper chamber of the first cylinder 51a and the pressure of the air in the upper chamber becomes higher than a predetermined pressure, the first piston 52a is located between the upper chamber of the first cylinder 51a and the buffer chamber 55a. Check valve is opened. Then, the air compressed by the first piston 52a is sent to the upper chamber of the second cylinder 51b via the first pipe 56 (FIG. 2) that connects the first cylinder 51a and the second cylinder 51b. In addition, the 1st piping 56 in this embodiment is a metal pipe.

  When the second piston 52b is driven in a direction to compress the upper chamber of the second cylinder 51b and the pressure of the air in the upper chamber becomes higher than a predetermined pressure, the second piston 52b is located between the upper chamber of the second cylinder 51b and the buffer chamber 55b. Check valve is opened. Then, the air compressed by the second piston 52b is sent to the air tank 10a via the second pipe 57 (FIG. 2) that connects the second cylinder 51b and the air tank 10a, and stored. The air tanks 10a and 10b communicate with each other via a third pipe (not shown). Therefore, the pressure in the air tanks 10a and 10b is kept uniform. The second pipe 57 and the third pipe in the present embodiment are metal pipes similar to the first pipe 56.

  Here, outside air is introduced into the upper chamber of the first cylinder 51a shown in FIG. That is, the first piston 52a compresses the outside air, and the second piston 52b further compresses the outside air (air) compressed by the first piston 52a. In other words, the first piston 52a is a first-stage low-pressure piston, and the second piston 52b is a second-stage high-pressure piston. The first cylinder 51a is a first-stage low-pressure cylinder, and the second cylinder 51b is a second-stage high-pressure cylinder. Thus, the air compressor 1 according to the present embodiment compresses air in two stages. Specifically, compressed air of, for example, around 1.0 [MPa] is generated in the first piston 52a, and compressed air of, for example, about 4.0 to 4.5 [MPa] is generated in the second piston 52b. The

  As shown in FIGS. 1 and 2, air sockets 15a and 15b, which are outlets for compressed air, are provided above the ends of the air tanks 10a and 10b. Further, pressure reducing valves 16a and 16b for adjusting the pressure of the compressed air are provided between the air tanks 10a and 10b and the air sockets 15a and 15b, respectively. The pressure of the compressed air adjusted by the pressure reducing valves 16a and 16b is measured and displayed by pressure gauges 17a and 17b installed in the vicinity of the pressure reducing valves 16a and 16b.

  As shown in FIG. 2, the air tank 10a is provided with a release valve 18a that automatically opens when the pressure in the air tank 10a, 10b becomes higher than a predetermined pressure. On the other hand, as shown in FIG. 3, the air tank 10b is provided with a drain device 18b. When the cock of the drain device 18b is operated, moisture (drain) in the air tanks 10a and 10b is compressed by compressed air. Extruded (or exhausted with compressed air). As shown in FIG. 1, an operation panel 19 is provided on the upper surface of the cover 14, and a start command for the motor 20 (FIG. 2) is provided via an input unit (not shown) provided on the operation panel 19. And the rotation speed is input.

  Here, during the operation of the air compressor 1, a load current is generated in the motor 20 shown in FIG. Therefore, the temperature of the motor 20 rises due to Joule heat accompanying the load current. Further, the temperatures of the cylinders 51a and 51b and the pistons 52a and 52b rise due to the compression heat generated in the compression process. Further, as the temperature of the motor 20 and the cylinders 51a and 51b increases, the temperature of the crankcase 40 in contact with them also increases. Therefore, in order to avoid overheating of the motor 20 and the compressed air generation unit 30 (the crankcase 40, the cylinders 51a and 51b, the pistons 52a and 52b, etc.), it is necessary to cool them.

  Therefore, as shown in FIGS. 2 and 3, a cooling fan 70 is installed on the opposite side of the crankcase 40 across the motor 20. As described above, the cooling fan 61 for mainly cooling the control circuit board 60 is fixed to the other end of the crankshaft 23. That is, in this embodiment, the cooling fan 61 is provided at one end of the crankshaft 23 and the cooling fan 70 is provided at the other end. In other words, the motor 20 and the compressed air generating unit 30 (the crankcase 40, the cylinders 51a and 51b, the pistons 52a and 52b, etc.) are arranged between the two cooling fans 61 and 70 facing each other.

  As shown in FIG. 3, the cooling fan 70 is fixed to one end of the crankshaft 23 protruding from the rotor 22 of the motor 20 and rotates integrally with the crankshaft 23. When the cooling fan 70 rotates, cooling air is generated, and the motor 20 and the compressed air generating unit 30 (the crankcase 40, the cylinders 51a and 51b, the pistons 52a and 52b, etc.) are cooled by the cooling air.

  Next, the structure of the first piston 52a and the second piston 52b shown in FIG. 3 will be described. However, although the first piston 52a and the second piston 52b have different dimensions, the structure is the same. Therefore, the structure of the first piston 52a will be described in detail, and the description regarding the structure of the second piston 52b will be omitted.

  As shown in FIG. 4, a first connecting rod 53a that transmits a driving force to the first piston 52a is connected to the first piston 52a so as to be rotatable (swingable). Specifically, the 1st piston 52a and the small end part 59 of the 1st connecting rod 53a are connected by the hollow piston pin 80 which penetrates these. More specifically, a piston pin 80 penetrating the first piston 52a in the radial direction is inserted into the first piston 52a, and this piston pin 80 is provided at the small end portion 59 of the first connecting rod 53a. The connecting hole 59a. A bearing 81 is interposed between the inner peripheral surface of the connecting hole 59 a and the outer peripheral surface of the piston pin 80. The bearing 81 in the present embodiment is a needle bearing and is press-fitted into the connecting hole 59a.

  A through hole 82 penetrating the peripheral wall of the piston pin 80 is formed at the center in the longitudinal direction of the piston pin 80, and the inner space 83 of the piston pin 80 and the needle bearing 81 communicate with each other through the through hole 82. ing. More specifically, the inner space 83 of the piston pin 80 and the roller portion 81 a of the needle bearing 81 communicate with each other through the through hole 82.

  Although not shown, a rider ring and a piston ring are mounted on the outer peripheral surface of the first piston 52a. Normally, the opening portions at both ends of the piston pin 80 are covered by the rider ring.

  Next, a procedure for supplying the lubricant to the needle bearing 81 will be described with reference to the drawings. First, as shown in FIG. 5, a container 91 filled with a desired amount of lubricant (grease) 90 is prepared. The illustrated container 91 is formed into a cylindrical shape from a resin material that is plastically deformed when pressurized. Specifically, the container 91 has a cylindrical main body 92 whose outer diameter is slightly smaller than the inner diameter of the piston pin 80 (FIG. 4), a first end 93 that closes one end side in the longitudinal direction of the main body 92, And a second end portion 94 that closes the other end in the longitudinal direction of the main body 92. That is, the first end 93 and the second end 94 are opposed to each other. However, the main body 92, the first end portion 93, and the second end portion 94 are integrally formed of the resin material, and the main body 92, the first end portion 93, and the second end portion 94 can accommodate the lubricant 90. A filling space is formed. In addition, an annular side wall 95 is provided around the entire first end portion 93, and a recess 96 is formed by the first end portion 93 and the annular side wall 95.

  Further, the main body 92 of the container 91 is formed with a protruding portion 97 protruding in the radial direction. A communication hole 98 that communicates with the inside and outside of the main body 92 is formed inside the protrusion 97, and the container 91 can be filled with a desired amount of the lubricant 90 through the communication hole 98. In this embodiment, the container 91 is filled with about 5 g of the lubricant 90.

  Next, the container 91 filled with a desired amount of the lubricant 90 is inserted into the piston pin 80 (FIG. 4). Specifically, as shown in FIG. 6A, the tip of the first jig 101 is inserted into the recess 96 (FIG. 5) of the container 91, and the tip surface of the first jig 101 is set to the first end. Assign to part 93. After that, as shown in FIG. 6B, the container 91 is pushed into the piston pin 80 from the one axial opening of the piston pin 80. When the container 91 is pushed to a predetermined position, the protrusion 97 of the container 91 is fitted into the through hole 82 of the piston pin 80, and the container 91 is positioned.

  Next, as shown in FIG. 6C, the second jig 102 is inserted into the piston pin 80 from the other axial opening of the piston pin 80. Thereafter, as shown in FIGS. 6D and 6E, the container 91 is sandwiched between the first jig 101 and the second jig 102, and the container 91 is pressed. That is, the container 91 is crushed by being sandwiched between the two jigs 101 and 102. Then, the container 91 is plastically deformed to reduce its volume, and the lubricant 90 filled in the container 91 is pushed out of the container 91 through the communication hole 98 (FIG. 5). The lubricant 90 pushed out from the container 91 is supplied to the needle bearing 81 through the through hole 82. Thus, when the protrusion 97 of the container 91 is fitted into the through hole 82 of the piston pin 80, the communication hole 98 (FIG. 5) provided in the container 91 and the through hole 82 ( 4), a series of lubricant supply paths is formed.

  Thereafter, as shown in FIG. 6 (f), the first jig 101 and the second jig 102 are extracted from the piston pin 80. As described above, a desired amount of the lubricant 90 is supplied to the needle bearing 81.

  As shown in FIG. 6 (f), after the supply of the lubricant 90 to the needle bearing 81 is completed, the container 91 is left as it is inside the piston pin 80. The protruding portion 97 of the container 91 left inside the piston pin 80 remains fitted in the through hole 82 and functions as a lid member for closing the through hole 82 thereafter. For this reason, the container 91 of this embodiment is formed of the fluororesin which is one of the resin materials excellent in heat resistance.

  As described above, in the present embodiment, the container 91 filled with a desired amount of the lubricant 90 is inserted into the piston pin 80, and the lubricant 90 filled in the container 91 is forcibly forced to the needle bearing 81. To be supplied. Therefore, a necessary and sufficient amount of lubricant 90 is easily and reliably supplied to the needle bearing 81. Further, the through-hole 82 that has formed the lubricant supply path between the container 91 and the needle bearing 81 is closed by the protrusion 97 of the container 91 after the supply of the lubricant is completed. Therefore, the lubricant 90 does not leak out. Further, the amount of lubricant supplied to the needle bearing 81 can be controlled by adjusting the amount of lubricant filled in the container 91.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the volume of the container 91 in the above embodiment is reduced by plastic deformation. However, the volume of the container 91 may be reduced without deforming the container 91. For example, the container 91 shown in FIGS. 7A and 7B includes a main body 92, a first end 93, and a second end 94, like the container 91 shown in FIG. However, the first end 93 of the container 91 shown in FIGS. 7A and 7B is fixed, while the second end 94 is movable. Specifically, the first end portion 93 is integrally formed with the main body 92. On the other hand, the second end portion 94 is screwed to the main body 92. More specifically, a female screw is formed on the inner peripheral surface of the main body 92, and the second end 94 is a screw member in which a male screw that is screw-coupled with the female screw formed on the main body 92 is formed on the outer peripheral surface. It is constituted by. Accordingly, when the second end portion 94 is rotated in a predetermined direction (when the second end portion 94 is rotated forward), the second end portion 94 moves in a direction closer to the first end portion 93 by the screw feeding action. As a result, the volume of the container 91 decreases. When the volume of the container 91 is reduced, the lubricant 90 filled in the container 91 is pushed out of the container 91 from the communication hole 98. It is obvious that when the second end portion 94 is rotated in the reverse direction, the second end portion 94 is separated from the first end portion 93.

  As described above, the second end portion 94 of the container 91 shown in FIGS. 7A and 7B can be moved in a direction approaching and separating from the first end portion 93 by a rotating operation. A hexagonal square hole 99 is formed on the upper surface of the second end portion 94, and the second end portion 94 can be rotated forward and backward by a hexagon stick wrench inserted into the square hole 99.

  The second end portion 94 can be moved to a position directly below the protrusion 97 by the rotation operation. In other words, the second end portion 94 can move to a position where the outer peripheral surface thereof overlaps with the communication hole 98. When the second end portion 94 reaches just below the projecting portion 97, the communication hole 98 is closed by the outer peripheral surface of the second end portion 94. That is, the second end portion 94 that reaches just below the protrusion 97 functions as a seal member that closes the communication hole 98.

  In the above embodiment, the container is left inside the piston pin after the supply of the lubricant to the bearing is completed. However, the container may be removed from the piston pin after the supply of lubricant to the bearing is complete. In this case, it is preferable to close the through hole of the piston pin with another member. Further, the bearing interposed between the piston and the connecting rod is not limited to a needle bearing or other rolling bearing, and may be, for example, a sliding bearing.

  After filling the container with the lubricant, the communication hole of the container may be closed. For example, the communication hole may be closed by a synthetic resin thin film. In this case, when the volume of the container decreases and the internal pressure of the container becomes higher than a predetermined pressure, the thin film is broken and the communication hole is opened.

  The supply of the lubricant to the bearing may be performed at the time of manufacture of the air compressor (before shipment) or may be performed at the time of maintenance of the air compressor by the user.

  Although the air compressor concerning the above-mentioned embodiment was a multistage type air compressor provided with two sets of cylinders and pistons, one set or three or more sets of cylinders and pistons may be used.

DESCRIPTION OF SYMBOLS 1 Air compressor 10a, 10b Air tank 13 Handle 14 Cover 15a, 15b Air socket 16a, 16b Pressure reducing valve 17a, 17b Pressure gauge 19 Operation panel 20 Motor 23 Motor rotating shaft (crankshaft)
30 Compressed air generating unit 40 Crankcase 51a First cylinder 51b Second cylinder 52a First piston 52b Second piston 53a First connecting rod (first connecting rod)
53b Second connecting rod (second connecting rod)
59 Small end portion 59a Connecting hole 80 Piston pin 81 Bearing (needle bearing)
82 Through-hole 83 Inner space 90 Lubricant 91 Container 92 Main body 93 First end 94 Second end 95 Annular side wall 96 Recessed portion 97 Protruding portion 98 Communication hole 99 Square hole 101 First jig 102 Second jig

Claims (7)

A reciprocating type air compressor that compresses air by a reciprocating piston,
A cylinder for accommodating the piston in a reciprocable manner;
A connecting rod for transmitting a driving force to the piston;
A hollow piston pin that passes through the small end of the piston and the connecting rod and connects the piston and the connecting rod;
A bearing interposed between the inner peripheral surface of the connecting hole provided in the small end and the outer peripheral surface of the piston pin passing through the connecting hole;
A through-hole penetrating the peripheral wall of the piston pin, and communicating the inner space of the piston pin and the bearing;
When a container filled with a lubricant is inserted inside the piston pin, a protrusion formed on the container is fitted into the through hole to position the container,
When the volume of the positioned container is reduced, the lubricant is pushed out through the communication hole formed in the protrusion, and supplied to the bearing through the through hole.
air compressor. When the container is pressed by a jig inserted inside the piston pin, the volume decreases due to plastic deformation.
The air compressor according to claim 1. The container is inserted into the inside of the piston pin from a first jig inserted into the inside of the piston pin through one opening in the axial direction of the piston pin and from the other opening in the axial direction of the piston pin. Sandwiched between the second jig and pressed,
The air compressor according to claim 2. The container has a first end and a second end facing each other,
At least the second end is movable, and moving the second end in a direction proximate to the first end decreases the volume of the container;
The air compressor according to claim 1. The container has a cylindrical body;
The first end is fixed to one end side in the longitudinal direction of the main body, the second end is screwed to the main body,
When the second end portion is rotated in a predetermined direction, the second end portion moves in a direction close to the first end portion.
The air compressor according to claim 4. The second end is movable to a position directly below the protrusion;
The second end portion that has reached directly below the protrusion becomes a seal member that closes the communication hole.
The air compressor according to claim 4 or 5. After the lubricant is supplied to the bearing, the protrusion becomes a lid member that closes the through hole.
The air compressor according to any one of claims 1 to 6.

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