JPS5843677Y2 - Hermetic electric compressor - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a steel pipe crankshaft for a hermetic electric compressor.

[Prior Art 1] Hereinafter, a conventional hermetic electric compressor will be explained with reference to FIGS. 1 and 2.

FIG. 1 is a longitudinal sectional view of a Scotchoke hermetic electric compressor, and FIG. 2 is an enlarged view of the X section in FIG. 1.

In Fig. 1, 1 is a steel pipe crankshaft, 2 is a frame, 3 is a rotor, 4 is a piston, 5 is a slider, 6 is a
is a slide can, and due to the action of the slider 5 and slide can 6, the rotational movement of the steel pipe crankshaft 1 becomes a reciprocating movement of the piston 4.

A crankshaft 1 made of steel pipe is supported by a frame 2, and the supporting portion serves as a bearing portion 2a.

Further, the rotor 3 is attached to the steel pipe crankshaft 1 by shrink fitting to the lower end of the bearing portion 2a.

Generally, the crankshaft, which is a main component of a hermetic electric compressor, is an expensive component because it requires time and effort to process.

Therefore, how to make a crankshaft cheaply is
This is very important in reducing the price of compressors.

Therefore, various methods of manufacturing crankshafts have been studied up to now, but they can be roughly divided into the following three types.

(1) Finish machining the steel pipe after plastic working, (2)
After roughing the forged product, finish machining is performed.

(3) After roughing the casting, finish machining is performed.

Among these, the cheapest manufacturing method is the method (1) in which the steel pipe is subjected to plastic working and then finish machining.

The reasons for this are that the force of the plastic working process to produce the material can be reduced and the takt time can be shortened, that the steel pipe is plastic worked as is, so the amount of material removed from the scraps is 100%, and that plastic working allows This is due to the fact that the dimensional accuracy of the steel tube can be improved, so machining only requires finishing machining, which simplifies the machining equipment and shortens the machining time.In this way, steel pipe crankshafts are ideal for machining processes and material extraction. It is shaped like this.

However, although steel pipe crankshafts have the advantages mentioned above, since they are made of steel pipes, when the rotor is shrink-fitted, the strength of the rotor is stronger, so the shrinkage of steel pipe crankshafts The fitting part and its vicinity are deformed,
There is a drawback that the deformation extends into the bearing part.

Therefore, as in the structure shown in FIGS. 1 and 2 described above, since the steel pipe crankshaft 1 has a hollow structure, the strength of the portion of the steel pipe crankshaft 1 into which the rotor 3 is shrink-fitted is lower than the strength of the rotor 3. weaker than

For this reason, the steel pipe crankshaft is deformed in the direction in which the diameter becomes smaller, as shown in FIG.

Since this deformation occurs within the bearing portion 2a, the role of the bearing portion 2a is halved.

There are ways to prevent this deformation, such as increasing the wall thickness of the steel pipe considerably, using special tough materials, and heat-treating the pipe, but these methods result in poor plastic workability. The positive aspects of using a steel pipe crankshaft, such as increased machining tact and material costs, are taken away.

Therefore, unless the deformation is allowed, there will be no merit in using a steel pipe crankshaft.

As a means of allowing deformation, it is sufficient to lengthen the bearing portion 2a by a length corresponding to the deformation length B in Fig. 2, but the length of the bearing portion is a factor that determines the height of the compressor. Therefore, if the length of the bearing section is increased, there is a problem in that the height of the compressor increases accordingly.

In addition, carbon steel pipe with a wall thickness of 2 mm (no quenching) is used for productivity.
The amount of deformation is approximately 20 μ for the 8 dimensions in FIG. 2 and the 10 mm A dimension, which is quite large.

As mentioned above, a steel pipe crankshaft is ideal from a manufacturing standpoint, but if you try to prevent deformation when the rotor is shrink-fitted, the disadvantage is that the solidity will be halved. There is.

[Purpose of invention]

This invention was made to improve this drawback.
This eliminates the need to use special materials, harden, or increase wall thickness for the steel pipe crankshaft, and also eliminates the need to increase the height of the compressor.

[Summary of the idea]

That is, a recess is formed on at least one of the bearing sides of the shrink-fitted part of the steel pipe crankshaft and the rotor, and this recess absorbs the deformation of the steel pipe crankshaft. This prevents the deformation from reaching the parts.

[Example of idea]

An embodiment of the present invention will be described below with reference to FIGS. 3, 4, and 5.

Figures 3, 4, and 5 show the X in Figure 1 where this invention was implemented.
Figure 3 shows a concave part on the outer periphery of the steel pipe crankshaft, Figure 4 shows a concave part on the inner surface of the rotor, and Figure 5 shows a tapered part on the inner surface of the rotor. The recessed portion is shown.

First, to explain with reference to FIG. 3, there is a recess 8 in the shrink-fitted portion of the steel pipe crankshaft 8 with the rotor 9 on the bearing portion Ia side.
A is provided along the entire circumference as shown by a dashed line.

The size of this recessed portion 8a is equal to or larger than the amount of deformation when the rotor 9 is shrink-fitted to the steel pipe crankshaft 8, and dimension C is the length of the deformed portion corresponding to dimension 8 shown in Fig. 2. The 0 dimension is equivalent to or more than the radial deformation amount corresponding to the A dimension shown in FIG.

Therefore, when the rotor 9 is shrink-fitted to the steel pipe crankshaft 8, the size of the recess 8a is as described above, and the deformation of the steel pipe crankshaft 8 is as shown by the solid line. Since the deformation is absorbed by the concave portion 8a, the deformation does not extend to the bearing portion 7a.

This recess can be provided on either the rotor side or the steel pipe crankshaft side, but if it is provided on the rotor 10 side as shown in Fig. 4, two types of cores with different inner diameters are stacked. Since the rotor 10 must be manufactured, it is very time consuming.

In addition, if this recess 10a is formed by cutting, the machining process will be two steps, and the rotor 1
Since the machinability of silicon steel plate is poor due to the formation of
The disadvantage is that cutting takes too much time.

Therefore, when providing a recess on the rotor side, as shown in FIG. It's better to keep it to a minimum.

On the other hand, when a recess 8a is provided in the steel pipe crankshaft 8 as shown in Fig. 3, the depth D of the recess 8a is approximately 20μ.
Since it is only a small amount, it has the advantage of being able to finish grinding the outer diameter and reduce the grinding force at the same time, so it does not increase the number of processing steps.

Therefore, it is ideal to provide a recess on the side of the steel pipe crankshaft.

Also, even if a recess is provided, the depth of the recess is about 20 μm, so
This does not affect the strength of the steel tube crankshaft.

[Effects of the invention] As described above, in the present invention, a recess is provided in either the steel pipe crankshaft or the rotor, and the deformation of the steel pipe crankshaft due to shrink fitting is absorbed by this recess. , there is no need to increase the length of the bearing or use a special material for the steel pipe crankshaft.
The benefits of the steel pipe crankshaft can now be maximized, which is highly effective.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a conventional Scotchoke type hermetic electric compressor, Fig. 2 is an enlarged view of the X section in Fig. 1, and Figs. 3, 4, and 5 show the implementation of the present invention. FIG. 2 is a diagram showing an enlarged view of a portion corresponding to the X portion in FIG. 1; 1... Steel pipe crankshaft, 2...
・Frame, 2a...Bearing part, 3...
Rotor, 4... Piston, 5... Slider, 6... Slide can, 7... Frame, 7a... Bearing section, 8...Steel pipe crankshaft, 8a...Recess, 9...
...Rotor, 10...Rotor, 10a...
... recess, 11 ... steel pipe crankshaft, 12 ... rotor, 12a ... tapered recess.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. In a hermetic electric compressor in which a steel pipe crankshaft is supported by a bearing, and a rotor is shrink-fitted to the steel pipe crankshaft up to the end of the bearing, the rotation with the steel pipe crankshaft is At least one of the shrink-fitting parts of the child,
A hermetic electric compressor characterized by having a recess formed around the entire circumference on the bearing side. 2. The hermetic electric compressor according to claim 1, which is formed with a concave portion on the side of the steel pipe crankshaft. 3. The hermetic electric compressor according to claim 1, which is formed with a tapered recess on the rotor side inner surface.