JPS63295877A - Shaft - Google Patents

Abstract

PURPOSE:To enhance mass-productivity by separately manufacturing a main shaft and a crank pin eccentrically arranged on an end of the main shaft and making them in a body by welding or screwing. CONSTITUTION:A shaft 11 consists of a main shaft 11a and a crank pin 11b. A hole 13 is arranged in a circumferential position of a flange section 12 of the main shaft 11a with a required eccentricity relative to the axis of the main shaft 11a. An inserting portion 16 of the crank pin 11b is inserted to the hole 13. Pressing an electrode against a flange section 15, the main shaft 11a and the crank pin 11b are joined in a body by projection welding. As a result, mass- production can be performed with simple production equipment of highly general purpose.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a shaft for use in small compressors, etc., which includes a main shaft and a crank pin eccentrically provided at the end of the main shaft. In particular, the present invention relates to improvements in the connection structure between the main shaft and the crank pin.

(Prior Art) FIG. 7 shows a conventional general small-sized compressor, and in the figure, reference numeral 1 indicates a shaft. This shaft 1 includes a main shaft 1a for transmitting driving force from a stator 2 and a rotor 3, and a main shaft 1a for converting the rotational force of the main shaft 1a into reciprocating motion.
The shaft 1 is rotatably supported by a frame 4, and the crank pin 1b is connected to a piston assembly 5.

That is, in the piston assembly 5, as shown in FIG. 7, a device end 5c composed of a piston 5a and a big end 5c formed at the end of a rod 5b is rotatably mounted on a crank pin 1b. . The eccentric rotation of the crank pin 1b causes the piston 5b to reciprocate within the cylinder 6, compressing the gas.

An oil pump 7 is provided at the lower end of the main shaft 1a, as shown in FIG. It is designed to be supplied to each part.

(Problems to be Solved by the Invention) In the conventional small compressor, the shaft 1 is manufactured by processing a casting or by using pipe material.
Both methods require large processing equipment, and in particular, when manufacturing by casting, it is necessary to process many parts, making them unsuitable for mass-produced products such as refrigerator compressors.

Further, in the conventional shaft 1, the main shaft 1a and the crank pin 1b are integrated, so it is difficult to assemble the shaft 1 to the frame 4 and assemble the crank pin 1b and the crank pin 1b.
There is a problem in that it is not easy to connect with.

Therefore, in some cases, the frame 4 and the cylinder 6 are made separately as shown in FIG. 8, and they are fixed with screws 9, or the big end 5C of the piston assembly 5 is fixed as shown in FIG. The piston assembly 5 is assembled into the cylinder 6 by dividing it into two parts and fixing them with a screw 9, or by making the crank pin 1b extremely large in diameter compared to the main shaft 1a as shown in FIG. , a method has been proposed in which the shaft 1 can be inserted from above.

However, all of these methods have problems in that they are uneconomical, require processing and assembly steps, and are unsuitable for mass production.

Therefore, as an improved version of these, for example,
Although a sleeve press-fitting method has been proposed as shown in Japanese Patent No. 0-9434, there is still a problem in terms of economy because the number of parts increases.

The present invention has been made in view of the current situation, and an object of the present invention is to provide a shaft that can be easily manufactured using simple manufacturing equipment and that can achieve high mass productivity.

[Structure of the invention]

(Means for Solving the Problems) The present invention is characterized in that the main shaft and the crank pin are manufactured separately and are connected together by welding or screwing.

(Function) In the shaft according to the present invention, the main shaft and the crank pin are manufactured separately, and then they are connected together by welding or screwing.

However, in view of recent technological trends, precision cold forging technology and highly stable welding technology have been established. These techniques are said to have extremely high economic efficiency, as they involve disassembling simple shapes, finishing them with high precision using cold forging, etc., and then joining the finished pieces to form the final shape. ing.

(Example) A first embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 11 indicates a shaft, and this shaft 11 is composed of a main shaft 11a and a crank pin.

As shown in FIG. 1, the main shaft 11a is formed by cold forging into a cylindrical shape with a closed upper end and a flange portion 12 at the upper end. A hole 13 is provided eccentrically by a required amount. Therefore, a crank pin llb is inserted into this hole 13 and connected together by projection welding.

The crank pin llb has a sliding portion 14 as shown in FIG.
The flange portion 15 and the insertion portion 16 are formed into a cylindrical shape, and when the insertion portion 16 is inserted into the hole 13 until the flange portion 15 contacts the upper surface of the flange portion 12, the flange portion 15 is inserted into the hole 13. is integrally welded to the main shaft 11a by projection welding by pressing with the end of an electrode (not shown). At this time, the flange portion 15 functions as a stopper for determining an appropriate welding position while maintaining the accuracy of the sliding portion 14.

An oil pump 19 is attached to the lower end of the main shaft 11a, as shown in FIG. As a result, oil 18 is supplied to each sliding part through the main shaft 11a and the crank pin 11b.

Further, the crank pin llb includes a piston 20a10, a piston 20b1 and a big end 20, as shown in FIG.
A big end 20C of a piston assembly 20 made of C is attached to the sliding portion 14, and the rotation of the shaft 11 causes the piston 20a to reciprocate within the cylinder 21.

Next, the operation of this embodiment will be explained.

When manufacturing the shaft 11, the main shaft 11a is first manufactured by cold forging, and a hole 13 is bored at a predetermined position in the flange portion 12 to communicate with the inside of the main shaft 11a.

Meanwhile, a crank pin llb was manufactured by the same method,
The insertion portion 16 is inserted into the hole 13.

Then, an electrode (not shown) is pressed against the flange portion 15 to bring the flange portion 15 into close contact with the upper surface of the flange portion to perform projection welding. Thereby, the main shaft 11a and the crank pin 11b are integrally connected.

At this time, it is also possible to not provide the flange part 15 on the crank pin llb and to press the lower end of the insertion part 16 directly to the bottom of the hole 13 and perform end face welding, but with this method This is not preferable because the flow of the oil 18 becomes poor.

On the other hand, in the welding method of the above embodiment, the flange portion 1
2. Since projection welding is performed between the parts 15 and 15, there is no occurrence of flash, and there is no risk of obstructing the flow of the pipe 18.

Further, since the main shaft 11a and the crank pin llb can be integrally connected after finishing the main shaft 11a and the crank pin llb, the main shaft 11a and the crank pin llb can be manufactured by simple manufacturing and maintenance such as centerless processing. In addition, the main shaft 11a and the crank pin ll
The process b is cold forging, which is extremely easy to mass-produce, and in the case of the main shaft 11a and crank pin llb, it is common and highly economical, so the shaft 11 can be mass-produced at low cost.

2 and 3 show a second embodiment of the present invention, in which a main shaft 11a and a crank pin llb are threadedly connected. .

That is, as shown in FIG. 2, the flange portion 12 of the main shaft 11a is provided with a female thread 22 at the same position as the hole 13 of the first embodiment, and the crank pin 11b is threadedly connected to this female thread 22. It is now possible to do so.

As shown in FIGS. 2 and 3, the crank pin llb is composed of a sliding portion 23 and a male threaded portion 24 having a smaller diameter than the sliding portion 23, and the male threaded portion 24 is screwed into the female thread 22. It is supposed to be done. The female thread 22 and the male thread 24 are threaded in a direction opposite to the rotational direction of the shaft 11, and the rotation of the shaft 11 causes the main shaft 11 to rotate.
Consideration has been taken to prevent the connection between a and crank pin llb from loosening.

Further, as shown in FIGS. 2 and 3, a square hole 25, for example, is provided in the axial center of the crank pin llb, and a tool (not shown) is inserted into this hole 25. By handling the crank pin 11b with
The crank pin Ilb can be tightened to a position where the stepped portion thereof comes into close contact with the upper surface of the flange portion 12.

In other respects, the configuration is exactly the same as that of the first embodiment.

According to this embodiment, as in the first embodiment, one shaft 11 can be produced using simple manufacturing equipment.

4 to 6 show a third embodiment of the present invention, in which the frame 17 and cylinder 21 in the first embodiment are shown.
It has an integrated structure.

That is, as in the second embodiment, the shaft 11 is of a type in which the main shaft 11a and the crank pin llb are threadedly connected, and the main shaft 11a is connected to the stator 26 as shown in FIG. A rotor 27 that generates driving force is press-fitted.

Further, the frame 17 and the cylinder 21 have an integral structure as shown in FIGS. 4 to 6, and the piston 2
As shown in FIG. 5, the piston assembly 20 consisting of a rod 20b1, a rod 20b1, and a big end 20c is attached to the cylinder 21 from the left side in the figure, and then the crank pin llb is screwed onto the main shaft 11a as shown in FIG. It is now connected.

In addition, in FIG. 4, the reference numeral 28 is a pulp assembly, and the reference numeral 2 is a valve cover.

Therefore, by screwing and integrating the main shaft 11a and the crank pin 11b, the frame 17 and the cylinder 21 can be made into an integral structure, which makes it possible to simplify the structure, while also reducing the ease of assembly. Never.

Note that when the main shaft 11a and the crank pin llb are integrated by screwing, there is a limit to maintaining the parallelism between the two, but as shown in FIG. 4, the piston 2 of the piston assembly 20
By connecting the rod 0a and the rod 20b with a ball joint, it is possible to have an extremely large tolerance in parallelism, so there are no similar failures in practical use.

[Effects of the Invention] - As explained above, in the present invention, the main shaft and the crank pin are manufactured separately and connected together by welding or screwing, so it is extremely versatile and simple. Due to the manufacturing process, mass production is easy and high reliability can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a shaft showing a first embodiment of the present invention;
FIG. 2 is a diagram corresponding to FIG. 1 showing a second embodiment of the present invention, and FIG.
The figure is a top view of FIG. 2, FIG. 4 is a sectional view of essential parts of a small compressor showing a third embodiment of the present invention, FIGS. 5 and 6 are explanatory diagrams showing the assembly procedure, and FIG. This figure is a diagram corresponding to FIG. 4 showing a conventional small compressor, and FIGS. 8 to 10 are explanatory diagrams each showing a conventional method for improving assembly efficiency. 11...Shaft, lla...Main shaft, 11b...
Crank pin, 12.15...flange part, 13...
- Hole, 17... Frame, 20... Piston assembly, 21... Cylinder, 22... Female thread, 25...
Male thread part, 25...square hole. Applicant's agent Mr. Sato Figure 4

Claims (1)

[Claims] 1. In a shaft equipped with a main shaft and a crank pin eccentrically provided at the end of the main shaft, the main shaft and the crank pin are manufactured separately and then integrated by welding or screwing. A shaft characterized by being connected to. 2. The shaft according to claim 1, wherein the main shaft has a flange portion at an end thereof, and the crank pin is welded or screwed to the flange portion. 3. Claim 2, characterized in that the main shaft is formed into a cylindrical shape whose flange side is closed by a forged material.
Shaft as described in section.