JPS6311352Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a screw compressor.

Conventionally, this type of rotor is known as shown in Japanese Patent Publication No. 54-37689, which was proposed earlier by the present applicant, and this has male and female rotors 2' and 3 as shown in Fig. 1. In view of the fact that it is extremely difficult to keep the axes parallel when assembling the rotors 2' and 3' into a case (not shown), the diameter of both rotors 2' and 3' is maximized at the center, and then extended to both ends. Outer axial direction line 18' of both rotors 2', 3',
19', 20', and 21' are configured to form a continuous arc.

In the figure, 5' is the drive shaft, 8' is the journal of the male rotor 2', 9' and 10' are the journals of the female rotor 3', 16' is the four teeth of the male rotor 2', and 17' is the journal of the male rotor 2'. 6 teeth of female rotor 3', XY,
OZ is the parallel axis of both rotors 2', 3'.

However, with the above-described structure, it takes a long time to process the center portions of both rotors 2' and 3' to have an arc height, and after the process, the teeth 16' and 17' are parallel to each other. In addition to being very difficult to assemble to ensure a good mesh, the mesh often fails after assembly, causing stiff mesh galling, vibration, and noise. Furthermore, when the two rotors 2' and 3' mesh with each other, a large meshing gap is formed at both end portions, and a large amount of liquid such as gas leaks from this gap, resulting in poor volumetric efficiency. There were flaws.

The object of this invention is to provide a screw compressor that can eliminate the drawbacks of the conventional compressors.

An embodiment of this invention will be described below with reference to the drawings.

Since most of this screw compressor is the same as that disclosed in Japanese Patent Publication No. 54-37689, the explanation of the same parts will be replaced with the above explanation, and the improved parts will be mainly explained. That's it.

In Figures 2 and 3, 2 and 3 are male and female rotors, respectively. Of these, male rotor 2 has approximately the same diameter on its suction side and discharge side, and the center part is slightly smaller than the diameter within the tolerance range. The axial lines 18 and 19 of the tip circle and root circle of the tooth 16 formed thereby form a continuous arc with the central portion as the apex, and the whole has a shape of a chisel barrel. , the rotor 3 has the same diameter on its suction side, discharge side, and central portion, and the axial lines 20 and 21 of the tip and root circles of the teeth 17 formed thereby are parallel straight lines. The entire body has a cylindrical shape. Both rotors 2 and 3 are housed in a case (not shown) with their axes XY and OZ parallel to each other, and their respective teeth 16 and
17 are designed so that their entire meshing surfaces mesh with each other at the center portions, and the rotation of the drive shaft 5 compresses gas from a suction port (not shown).

That is, in the above-mentioned case, the male rotor 2 has a small diameter on both sides except for the central part, and a relief is formed in this small diameter part, and the male rotor 3 has the same diameter throughout. Rotor 2, 3
If they are arranged exactly in parallel, then the male rotor 2
The teeth of the two rotors 2 and 3 will mesh with each other in the central part of the rotors 2 and 3. Furthermore, due to inaccurate machining of the rotors 2 and 3, or poor precision after assembly when the rotors 2 and 3 are fixed with bearings at both ends, the two axes of XY,
Even if both rotors 2 and 3 are not exactly parallel due to non-parallel OZ or non-parallel to both axes XY and OZ of each part of each rotor 2 and 3, both rotors 2 and 3 , 3 are engaged only slightly to the left or right from the center portion, and smoothness is not impaired and rotation is not hindered.

In the above example, the center part of the male rotor 2 is configured to have an arc height, but the present invention is not limited to this, and the center part of the female rotor 3 may be configured to have an arc height. It is sufficient that the central portion of the rotor has an arc height and that the other rotor has the same diameter, and various other changes and modifications can be made to this invention. Also, in this screw gear, the male tooth bottom is the same as the male pitch cycle,
This also includes eye tooth profiles in which the female outer diameter is the same as the female pitch cycle.

This idea is as described above, and the diameter of one of the two rotors is maximized at the center, and then the outer axial direction line forms a continuous arc from the center to both ends. Since both rotors have the same diameter and their outer axial lines form parallel straight lines, there is no need for both rotors to have an arc height in the center like in conventional rotors, and only one rotor has the same diameter. Therefore, the processing can be performed easily and in a short time. In addition, the meshing after processing can be performed accurately even if the parts necessary for meshing do not maintain an accurate parallel relationship, preventing rattling from occurring in the meshing, and making assembly work extremely easy. , and also does not generate noise.
Furthermore, when the two rotors mesh, the meshing gap formed at both end portions can be reduced to about 1/2 of the conventional one, and the one end portion on the discharge side of both rotors is Expansion occurs due to the heat of compression,
One end of one rotor has a gentle arc curve, and one end of the other rotor has its outer circumferential axial direction expanding into a continuous arc opposite to the arc of the one rotor. By approaching one end of the rotor and further reducing the gap formed between the one end of both rotors, it is possible to reduce liquid leakage as much as possible and increase volumetric efficiency. It has a good effect.

[Brief explanation of the drawing]

Figure 1 is a front view of the rotor of a conventional screw compressor, Figure 2 is a front view of the rotor of this invention, and Figure 3 is a front view of the rotor of the conventional screw compressor.
The figure is a longitudinal sectional side view taken along the - line in FIG. 2. 2...male rotor, 3...female rotor.

Claims (1)

[Scope of utility model registration request] Male and female 2 with spiral teeth on the circumference
In a screw compressor, two rotors are arranged in parallel and their teeth mesh with each other, and the teeth of the male rotor are mostly addendums, and the teeth of the male rotor are mostly dedendums. The diameter of one is the maximum at the center, and the outer axial direction lines form a continuous arc from then to both ends, and the diameter of the other one is the same in all parts, and the outer axial lines are parallel. A screw compressor characterized by forming a straight line.