JPS59208179A - Reciprocative compressor - Google Patents

Abstract

PURPOSE:To enhance the compressing capacity by fixing an eccentric crank cam to a motor shaft, setting the power transmission position from a locking piston to a crank cam on the cylinder shaft, and thereby aligning the piston with the cylinder automatically. CONSTITUTION:Rotation of a drive shaft 8 leads to swings or rotation of a bearing 6 through a crank shaft 7, and the piston element 2a of a piston 2 reciprocates in the bore of the cylinder part 1a. At this time, said bearing 6 is situated approx. at the central shaft of piston 2, so that the load from compression chamber 22 is applied to the bearing. Accordingly the locking piston 2 is always in alignment in the axial direction with the bore of cylinder part 1a to eliminate possibility of single-sided contact of the piston ring 4 with the bore of the cylinder part 1a. Thus it is free from generation of abnormal wear to ensure an enhanced sealing performance and durability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small-sized, small-flow reciprocating compressor, which is effective when used as an air pump, for example.

Conventionally, a locking piston that integrates a piston and a connecting rod has been used in small reciprocating compressors, but the locking piston is axially fixed to the motor shaft and crankshaft with screws or the like. However, it is difficult to align the axes of the cylinder and piston, and if these axes are misaligned, the sealing performance of the piston ring deteriorates, compression performance deteriorates, and the durability of the piston ring deteriorates.

Therefore, the present invention fixes an eccentric crank cam to the motor shaft, and sets the power transmission position of the locking piston and crank cam on the cylinder axis, so that the piston can be automatically aligned with the center of the cylinder, and the compression The purpose is to improve the performance and durability of piston rings.

A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross section of a reciprocating compressor, and FIG. 2 shows a cross section taken along line A--A in FIG.

In the figure, reference numeral 1 denotes a housing made of aluminum, and this housing 1 is provided with a cylinder portion 1a, and cooling fins 1b are provided on the outside of the cylinder portion 1a. 2 is a locking piston in which a piston part 2a and a connecting rod part 2b are integrally molded, and the piston part 2a is disposed on the inner periphery of the cylinder part 1a, and a charge-in valve 3 is wound around the end surface of the piston part 2a. is held by. The piston part 2a has a suction passage 2C.
is provided. Further, a piston ring 4.0 ring 5 provided on the piston portion 2a provides a seal between the screw portion 2a and the cylinder portion 1a.

Furthermore, a spring bearing 6 is driven into the connecting rod portion 2b of the locking piston 2, and the crankshaft 7
is mated to. Here, the bearing 6 is disposed approximately on the central axis of the locking piston 2, and is located on the cylinder 1.
It is also located approximately at the center with respect to the axial direction of a. Reference numeral 7a denotes a balance weight portion integrally molded on the crankshaft 7, which adjusts unbalance that occurs during reciprocating motion of the locking piston 2 and the like. The locking piston 2 and crankshaft 7 are both made of aluminum to reduce weight.

8 is a drive shaft of the electric motor 10, and the end of this shaft 8 is integrally molded with a threaded portion 8a and a two-sided portion 8b. The crankshaft 7 is then fitted into two surface portions provided on the crankshaft 7, and the crankshaft 7 is fixed to the drive shaft 8 by a nut 9. Further, the cam portion 7b of the crankshaft 7 that fits into the bearing 6 fixed to the locking piston 2 and the drive shaft 8 are given a predetermined eccentricity. The axial length of the cam portion 7b is longer than the width of the bearing 6, and it can freely slide in the axial direction, so that the position of the crankshaft 7 may shift in the axial direction due to machining errors of the drive shaft 8. However, the center of the cylinder part and the locking piston 2 are taken into account so that they do not change.

The electric motor section 10 includes an armature (not shown) fixed to the drive shaft 8, a magnet (not shown), and the like. The housing 1 and the holder 11 are fixed to the housing 12 of the electric morph IO by tapping screws (not shown). Reference numeral 13 denotes an oil-impregnated bearing that rotatably holds the drive shaft 8, and is held by a retainer 14, and a felt 15 holding oil is disposed around the outer periphery of the oil-impregnated bearing 13.

A spacer 16 is provided between the commutator 17 and the oil-impregnated bearing 13.
is provided to prevent the drive shaft from moving in the axial direction. Reference numeral 18 denotes an O-ring held in the housing 1 to remove dust from the outside into the crank chamber 19.

Prevents water from entering.

20 is a discharge valve, and this discharge valve 20 is in contact with the housing 1 at the seat surface IC, and is pressed against the seat surface 1c by a spring 21. Reference numeral 1d denotes a discharge hole, which communicates with a compression chamber 22 formed by the cylinder portion 1a and the end surface of the locking piston 2. 23 is a stopper that covers the upper surfaces of the discharge button t20 and the spring 21, and is sealed by an O-ring 24 and fixed by a circlip 25. Reference numeral 1e denotes a discharge nipple provided in the housing, which is connected to other devices with a screw 1f.

Reference numeral 2b denotes a cover that covers the crank chamber, and is fixed to the housing 1 together with a gasket 28 by machine screws 27.

A bushing 29 covers the lower surface of the housing 1 and is made of elastic rubber.A suction filter 30 is held by adhesive on the bushing 29, and the bushing 29 covers the bottom surface of the housing 1.
and the atmosphere are in communication via this suction filter 30. This suction filter is positioned below when the reciprocating compressor is installed to prevent water from entering.

Next, the operation of the pressure 1'1 machine having the above configuration will be explained.

When the electric motor section 10 is energized, the drive shaft 8 rotates, and the bearing 6 fixed to the connecting rod section 2b of the locking piston 2 opens around the drive shaft 8 by the crankshaft 7 fixed eccentrically to the drive shaft 8. Rotate. The piston portion 2a of the locking piston 2 holding the piston ring 4 reciprocates along the inner periphery of the cylinder portion 1a of the housing 1 in response to this rocking rotation.

As a result, the discharge valve 20 opens during the compression stroke (compression chamber volume is small), and compressed air is supplied from the discharge nipple 1e to other devices. Next, during the suction stroke, the compression chamber 22 becomes a negative pressure, so the suction valve 3 opens, and air is introduced through the suction filter 30.

Dust and the like are removed from the introduced air by the suction filter 30.

Next, the reciprocating motion of the locking piston 2 will be described in detail. When the king piston 2 moves back and forth, the bearing 6 fixed to the locking piston 2
Because it is located almost on the central axis of
The force received from 2 is applied equally to the bearing 6, and the bearing 6, that is, the locking piston 2
In the axial direction, the center always almost coincides with the inner periphery of the cylinder portion 1a. Therefore, even if the position of the crankshaft 7 shifts in the axial direction due to a machining error of the drive shaft 8, the center of the cylinder portion 1a and the center of the locking piston 2 will almost match, so the piston ring 4 will be aligned with the inner circumference of the cylinder portion. ,
There is no uneven contact (the compression chamber 22 and the crank chamber 19 can be reliably sealed, and there is no abnormal wear caused by the uneven contact of the cylinder 4, or abnormal wear caused by the uneven contact of the bearing 6), resulting in good durability. can have

Next, a second embodiment of the present invention will be explained based on FIG.

A crankshaft 40 is fixed to the drive shaft 41 by screwing. Reference numeral 40a denotes a balance weight section that adjusts unbalance that occurs during reciprocating motion of the locking piston 42 and the like. 40b is a pin portion integrally formed on the crankshaft 40, and is fitted into a bearing 43 driven into the locking piston 42.

The bearing 43 is disposed approximately on the center line of the locking piston 42, and is also located approximately at the center in the axial direction of the cylinder portion 1a.

Furthermore, the bearing 43 is shorter in width than the bottle part and can freely slide in the axial direction, and the center of the cylinder part 1a and the locking piston 42 remains unchanged as in the first embodiment, so that the bearing 43 can be smoothly moved. You can get great durability.

In addition, 1. Although a slide bearing was used as the bearing in the second embodiment, a ball bearing may also be used.

Also number 1. Although the common suction valve in the second embodiment is held on the locking piston, it may also be mounted on the housing side in the same way as the discharge valve.

Rani No. 1. Although the second embodiment has been described as a compressor that supplies compressed air, it goes without saying that it can also be used as a vacuum pump that supplies negative pressure.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing one embodiment of the reciprocating compressor of the present invention, FIG. 2 is a plan view of the top of the piston shown in FIG.
The figure is a partial sectional view showing another embodiment. 8... Drive shaft, 7... Crankshaft, 2b... Connecting rod fJ, la... Cylinder, 2... Piston,
6...Bearing. Representative Patent Attorney Takashi Okabe

Claims (1)

[Claims] The connecting rod includes a drive shaft, a crankshaft fixed to the drive shaft, a connecting rod that is connected to the crankshaft and swings, and a piston that reciprocates within a cylinder in response to the swing of the connecting rod. In the device having a locking piston in which the connecting rod part and the piston are integrally molded, the bearing fixed to the connecting rod part is aligned with the central axis of the locking piston and is slidable in the axial direction of the crankshaft. A reciprocating compressor characterized by: