JPS5848785A - Reciprocating compressor - Google Patents

Abstract

PURPOSE:To prevent the breakage of a suction valve plate or the like by a method wherein a mechanism, reducing the amount of eccentricity between a crank and a shaft when an abnormal high pressure is caused in a cylinder upon compressing liquid, is provided on a crank shaft to reduce a compressing effect and avoid the abnormal high pressure in the cylinder. CONSTITUTION:The configuration of the shaft at an engaging part between the shaft 21b and the crank 21a of the crank shaft 21 is shaped into a square 21b', the configuration of a hole for engaging with the crank 21a is shaped into a rectangular 21a' which is longer than the square 21b' of the shaft only in an eccentric direction, the square 21b' of the shaft is slidably inserted into said engaging hole, and the amount of eccentricity between the crank 21a and the shaft 21b is formed so as to be variable. When a piston is brought into a condition to compress the liquid, the pressure in the cylinder becomes higher than the maximum pressure upon a stationary operation near the upper dead point of the piston, this internal pressure is transmitted to the crank 21a, the crank 21a moves against a spring 22 into a direction to reduce the amount of eccentricity and reduces the compressing effect thereof. According to this action, the abnormal high pressure in the cylinder upon compressing the liquid may be avoided and the breakage of the suction valve plate, a bearing or the like may be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reciprocating pressure iM machine in which a crank is provided on a rotating shaft and a piston is reciprocated via a connecting rod by eccentric rotation of the crank. It is related to.

The first example of a conventional reciprocating compressor is a hermetic electric compressor.
This will be explained in detail in FIG.

In Figure 1, 1 is the crankshaft, and the upper bearing 2
, is supported by a lower bearing 3, and has an electric motor 4 disposed above. The compressor part forms a cylinder 6 integrally with the frame 5,
A cylinder head 7 and a head cover 8 are disposed on the end surface of the cylinder, and inside the cover 8 there is a suction chamber 9 and a discharge chamber 1.
0 and 1, and the suction chamber 9 has a suction pipe 11 whose upper end is open.
is connected to the discharge chamber 10, and a discharge pipe 12 is connected to the discharge chamber 10. A histone 13 is housed inside the cylinder 6 and connected to the crankshaft 1 via a connecting rod 14. The electric compressor connected with the electric motor as described above is housed in a closed container 15. 1 indicates the gas return pipe.

FIG. 2 shows the crank portion of the crankshaft of the compressor.

The crankshaft 1 is formed by eccentrically mounting a crank 1a on a shaft 1b and identifying a key ICKI, transmitting the rotation of the shaft 1b to the crank 1a, and the crank rotates eccentrically.

When the above-mentioned hermetic electric compressor is used as a compressor for a refrigeration system, the refrigerant gas flowing from the refrigerant circuit into the hermetically sealed chest 15 through the return pipe 16 is sucked through the suction pipe 11 by operating at pressures 1 & 1IIIA. The air is sucked into the cylinder 6 through the chamber 9 and the suction valve (not shown) in the cylinder head 7, and is then compressed by the reciprocating motion of the histone 13, and then flows through the discharge valve (not shown) in the cylinder head 7 into the discharge chamber 10. The liquid is then discharged to the outside of the machine via the discharge pipe 12.

However, at the start of operation or due to temperature conditions, liquid is sucked into the cylinder 6, and when this liquid is compressed, the pressure inside the cylinder 6 near the top dead center of the piston 13 is higher than the maximum pressure during steady operation. It gets expensive.

However, in the above structure, since there is no buffer mechanism in the connection mechanism of the histone 13, connecting rod 14, and crank 181 shaft 1b, the above abnormal internal pressure acts on the valve device and bearing section of the cylinder head 7, causing excessive force to be applied to the four parts. Damage may occur to the valve gear, valve gear and bearings.

The present invention was invented in view of the above, and is advantageous in that it reduces the amount of eccentricity between the crank and the shaft when compressing liquid in a compressor, thereby reducing the compression effect, avoiding abnormally high cylinder internal pressure, and preventing the suction valve plate, bearing The purpose is to prevent accidents involving damage to parts.

The structure of the present invention is that the crankshaft is provided with a mechanism that moves the crank in a direction to reduce the amount of eccentricity between the crank and the shaft when the cylinder internal pressure becomes abnormally high during liquid compression.

An embodiment of the present invention will be explained with reference to FIGS. 3 and 4.

In the figure, a detail 21b of the crankshaft 21 and a crank 2
The shape of the shaft of the retaining portion with 1a is a square 21b/, and the shape of the retaining hole of the crank 21a is a rectangle 2151/ which is longer than the square 21b' of the shaft portion only in the eccentric direction. The square 21b' portion of the shaft is slidably inserted,
That is, the crank 21a and the shaft 21b are formed so that the amount of eccentricity between them can be changed. 22 is a spring, and the crank 21a
The spring 22 is positioned so that the amount of eccentricity is maximum, and is inserted into the space created on the left side of the square 21b/section in the illustration, and this spring 22 is inserted into the space created on the left side of the square 21b/section, and this spring 22 is inserted into the piston and connecting rod 14 during compression during steady operation.
As a result, the eccentricity of the crank 21a is maintained by a spring force greater than the maximum load acting on the crank 21a, and a spring force greater than the maximum load acting on the crank 21a. Reference numeral 23 denotes a holding plate which prevents the crank 21a from moving in the axial direction, and is provided on both end surfaces of the square 21b/section of the shaft portion. Since the other parts are the same as those in FIG. 1, illustration and explanation will be omitted.

In the above structure, when liquid is sucked into the cylinder and becomes compressed, the pressure inside the cylinder near the top dead center of the piston is higher than the highest pressure during steady operation. The load is transmitted to the connecting rod 14 and the crank 21a, and the load is greater than the initial force of the crank 218u and the crank 218u, and the crank 218u moves in the direction of decreasing eccentricity by pressing the crank 218u and the crank 22, reducing the compression effect. Prevent the internal pressure of the cylinder from becoming abnormally high.

As explained above, according to the invention, abnormally high pressure inside the cylinder during liquid compression can be avoided, and damage to the valve device, bearing, etc. of the cylinder head can be prevented.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view of a conventional hermetic compressor, and Figure 2 is a vertical cross-sectional view of a conventional hermetic compressor.
FIG. 3 is an enlarged cross-sectional view taken along the line 1-1 in the figure, FIG. 3 is a vertical cross-sectional view of a supporting part showing an embodiment of the present invention, and FIG. 4 is a plan view of FIG. 3. 21...Crankshaft 21a...Crank 21
a'...Rectangular retaining hole 21b...Shaft portion 21b
/... Rectangle of shaft 22... Spring 23...
・Holding board agent Patent attorney Usuki 1) Interest (Ryo≧)

Claims (1)

[Claims] The details of the crank retaining part of the crankshaft are formed into a square shape,
The retaining hole of the crank is formed into a rectangular shape that is as long as the above rectangular shape only in the eccentric direction, and the square part is inserted into the retaining hole of the crank so that it can slide in the eccentric direction of the crank, and the maximum load that is applied during compression during steady operation is The spring compressed with the above initial force,
The reciprocating dynamic pressure version is inserted into the space of the retaining part so as to suppress and hold a predetermined amount of eccentricity of the crank, and reduces the eccentricity of the crank when a load greater than the initial force of the spring is applied during compression. Machine.