JPH0227174A - Piston device of compressor - Google Patents

Abstract

PURPOSE:To prevent decrease in strength of a crankpin and to avoid massiveness of a cylindrical body by intermediately inserting a spacer either in the side of a negative load or in that of anti-negative load between the cylindrical body inserted fit into a crankpin and the crankpin. CONSTITUTION:A crank shaft 5 having a crankpin 15 and a balancer 18 integrated is inserted from above in a bearing part 8 of a motor case 6. The setting of the crank shaft 5 is made in such a way that the crankpin 15 comes to a bottom dead point. As a piston 14 that is linked to a connection rod 13 having a cylindrical body 12 is inserted into a cylinder 9, the cylindrical body 12 is obliquely inserted in the crankpin 15. Then, a spacer 17 is pressed-fit into a gap generated in the side of anti-negative load between the cylindrical body 12 and the crankpin 15 to complete the work.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a piston device for a compressor used in refrigerators, freezer showcases, and the like.

(B) Conventional Technology Conventionally, a piston device of this type of compressor, that is, a compressor equipped with a motor case in which a cylinder is integrally formed,
For example, as disclosed in Japanese Patent Publication No. 51-21165, the inner diameter of a cylindrical body to be inserted into the crank pin is made larger than the outer diameter of the bottle, and the crank pin is set at a predetermined position in the motor case. On the other hand, with the piston inserted into the cylinder, tilt the connecting rod supported by the piston to insert the cylindrical body into the crank pin, and then fill the space between the cylindrical body and the crank pin with a cylindrical spacer. It was composed of

(c) Problems to be Solved by the Invention However, according to the above configuration, a cylindrical spacer is required when connecting the cylindrical body and the crank pin, so the cylindrical body is enlarged over the entire circumference by the spacer. Alternatively, the crank pin must be formed to have a small diameter, resulting in problems such as an increase in the size of the compressor and the occurrence of play due to deformation due to reduced strength of the crank pin.

The present invention has been developed in view of these points, and it promotes downsizing of the compressor by preventing the increase in the size of the cylindrical body and the decrease in the strength of the crank pin. The purpose is to provide a piston device.

(d) Means for Solving the Problems The present invention is characterized in that a compressor section and an electric motor section for driving the compressor section are housed in a sealed case, and these compressor sections are connected by a crankshaft, and the electric motor section A cylinder constituting the compressor section is integrally formed with the motor case fixed to the motor case, and a piston that reciprocates within the cylinder and a crank pin of the crankshaft are connected by a connecting rod having a cylindrical body that is fitted into the pin. In those that are connected, a spacer having a shape corresponding to the circumferential surface of the crank pin is inserted only on the load side or the anti-load side between the cylinder and the crank pin.

(E) Function The compressor piston device of the present invention has the above-described structure, so that even if the cylinder is integrated with the motor case,
Because the connecting rod and crankshaft can be assembled without enlarging the entire circumference of the cylinder or reducing the diameter of the crank pin, it is possible to promote downsizing of the compressor, as well as increase the strength of the crank pin. This can reduce the occurrence of looseness, etc.

(f) Example Embodiments of the present invention will be described below based on the drawings.

Reference numeral 1 designates a hermetic compressor in which a compressor section 3 and an electric motor section 4 for driving the compressor section 3 are housed in a closed case 2, and these compressor sections 3.4 are connected by a crankshaft 5. 6 is a motor case fixed to the electric motor section 4. In this motor case, a mounting leg 7 to the electric motor section 4, a bearing section 8 of the crankshaft 5, and a cylinder 9 are integrally formed. Reference numeral 10 denotes a piston device constituting the compressor section 3, which has a sphere 11 at one end and a cylinder 12 having an elliptical planar shape (an ellipse whose major axis is located in the sliding direction of the piston 14) at the other end. A rod 13, a piston 14 connected to the sphere 11 by a ball joint system and sliding inside the cylinder 9, and a crank pin 15 formed at the upper end of the crankshaft 5 and fitting the cylindrical body 12 on the outside. It has a curved surface 16 corresponding to the circumferential surface of the crank pin 15, and the cylindrical body 12 and the crank pin 15
A spacer 17 having a crescent-shaped cross section is inserted only on the anti-load side between the two. 18 is a balancer formed on the crankshaft 5, and has a slusl i-plane on the lower surface.

The piston device of the compressor thus constructed is assembled in the following manner as shown in FIG. First, the crankshaft 5 that integrally includes the crank pin 15 and the balancer 18 is inserted into the bearing portion 8 of the motor case 6 from above. At this time, the crankshaft 5 is set so that the crank pin 15 is at the bottom dead center position. On the other hand, while inserting the piston 14 fully connected to the connecting rod 13 having the cylindrical body 12 into the cylinder 9, the cylindrical body 12 side of the connecting rod 13 is tilted upward using the spherical body 11 as a fulcrum, and then the piston 14 is connected. The rod 13 is lowered and the cylindrical body 12 is inserted diagonally into the crank pin 15. At this time, since the cylindrical body 12 is formed in an elliptical shape with its long axis in the sliding direction of the piston 14, it can be easily inserted from an angle. Then, a spacer 1 is inserted from above into the gap formed on the opposite load side between the cylinder body 12 and the crank pin 15.
Press in 7 to complete.

In the piston device assembled in this way, the cylinder 12 is
Although it becomes larger in the long axis direction by the size of the spacer 17, it can be formed to the same size as the diameter of the crank pin 15 in the short axis direction. It is no longer necessary to make the crank pin extremely large or to make the crank pin a diameter of 1/4 inch, which makes it possible to promote downsizing of the compressor and to prevent rattling by increasing the strength of the crank pin.

Further, since the spacer 17 is inserted only on the opposite load side which is not subjected to much stress, a material with excellent self-lubricating properties such as synthetic resin can be used, and a high-performance compressor with improved lubrication properties can be provided.

In this embodiment, the spacer 17 is inserted only in the gap between the cylinder body 12 and the rank pin 15 on the opposite load side, but it may also be inserted only in the load side, and in this case, the spacer 17 Since a large amount of stress will be applied to it, it is desirable to make it from a material with high wear resistance.

(G) Effects of the Invention As described above, the present invention makes it possible to make the cylindrical body larger over the entire circumference or to form the crank pin with a smaller diameter even if the cylinder is integrally formed with the motor case. It is possible to assemble the piston device without having to do anything, promote downsizing of the compressor, and provide a high-performance piston device for the compressor without backlash.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a hermetic compressor showing an embodiment of the present invention, Fig. 2 is a cross-sectional view of the screw device, Fig. 3 is a cross-sectional view of the main part of the piston device, and Fig. 4 is a cross-sectional view of the piston device. FIG. 3 is an explanatory diagram showing a method of assembling the piston device. 5...Crankshaft, 6...Motor case,
9... Cylinder, 10... Piston device,
12... Cylindrical body, 13... Connecting rod, 14
... Piston, 5... Crank pin, 17...
·Spacer.

Claims (1)

[Claims] (1) A compressor unit and an electric motor unit that drives it are housed in a sealed case, and these two units are connected by a crankshaft, and the compressor unit is housed in a motor case fixed to the electric motor unit. In a device in which the constituent cylinders are integrally formed, and a piston that reciprocates within this cylinder and a crank pin of a crankshaft are connected by a connecting rod having a cylindrical body that is fitted into the pin, the cylindrical body and A piston device for a compressor, characterized in that a spacer having a shape partially corresponding to the peripheral surface of the crank pin is inserted only on the load side or the anti-load side between the crank pins.