JP2545218Y2 - Screw type turbocharger or compressor rotor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a screw type supercharger used for supercharging of an automobile engine or the like or a rotor of various industrial small screw compressors.

[Prior Art] A screw type supercharger or a compressor is inserted into a casing 1 in parallel by engaging two rotors of a male rotor 2 and a female rotor 3 as schematically shown in FIG. 2 and FIG. Then, the intake air from the air inlet 4 at one end of the casing 1 is compressed by the rotation of the rotors 2 and 3 in the space formed by the rotors 2 and 3 and the other end of the casing 1. Is taken out from the air outlet 5 on the other end side to supply air to the engine and the like.

Conventionally, as the male rotor 2 and the female rotor 3 used in such a screw type supercharger or compressor, conventionally, the rotor main bodies 2a, 3a and the shafts 2b, 3b are integrally formed of iron, that is, What used to form the rotor bodies 2a, 3a and the shafts 2b, 3b by shaving off iron lumps was used. The one-piece structure made of iron
Although there is no difference in thermal expansion of the material between the shafts a and 3a and the shafts 2b and 3b, this is ideal, but there is a problem that it is not suitable especially for mounting on a car because of its heavy weight.

In order to solve this problem, a rotor body 2a, 3a and shafts 2b, 3b having an integral structure with an aluminum alloy has been proposed.

When the shafts 2b, 3b as well as the rotor bodies 2a, 3a are made of an aluminum alloy, they are lightweight, which is advantageous in handling such as mounting on automobiles, and the material is soft, so processing is easy and mass production is possible. However, on the other hand, there is a problem that the aluminum alloy shafts 2b and 3b are soft and have low strength and cannot be used.

Therefore, conventionally, the rotor bodies 2a and 3a are made of an aluminum alloy, the shafts 2b and 3b are made of iron, and the rotor bodies 2a and 3a are
A male rotor 2 and a female rotor 3 having a configuration in which b and 3b are integrated by press fitting or the like have been proposed.

[Problems to be Solved by the Invention] However, since aluminum alloy has good heat conduction, heat at the air outlet 5 side of the supercharger or compressor shown in FIG. The temperature on the side 4 also increases, and accordingly, the aluminum alloy rotor bodies 2a, 3a and the iron shafts 2b, 3b are also heated, but the aluminum alloy rotor bodies 2a, 3a are heated due to the difference in thermal expansion between the aluminum alloy and iron. Difference between the steel shafts 2b and 3b. Generally, the aluminum alloy and iron are integrated by shrink-fitting, press-fitting, bonding, or the like. Due to this difference in expansion, the aluminum alloy rotor bodies 2a and 3a tend to expand due to heat. 2b, 3b, iron shaft 2b, 3b
Is stretched by the aluminum alloy rotor bodies 2a and 3a, though it does not want to stretch, and the two are pulled and balanced with each other. The point of this balance is that the male rotor 2 and the female rotor 3 The gap between the male rotor 2 and the female rotor 3 becomes too small due to the difference between them, and in some cases, there is a problem of contact or welding (seizure). That is,
The male rotor 2 has a thicker rotor body 2a, so that the thermal expansion of the aluminum alloy rotor body 2a is more predominant and balances where the overall elongation is greater, while the female rotor 3 is Since the wall thickness is thin, the thermal expansion of the iron shaft 3b is more dominant, and the balance is made where the total elongation is small, and a total elongation difference x occurs as shown in FIG. There is a problem that the gap between the rotor 2 and the female rotor 3 becomes too small and eventually comes into contact and welds.

For this reason, the gap between the male rotor 2 and the female rotor 3 should originally be small in order to improve the compression efficiency. However, in order to avoid the above-mentioned welding, the gap between the male rotor 2 and the female rotor 3 is reduced. It was necessary to increase the gap in advance, and the efficiency was reduced accordingly.

Accordingly, the present invention is to provide a rotor which can reduce or minimize the difference in extension between the male rotor and the female rotor so that the gap between both rotors can be reduced.

Means for Solving the Problems In order to achieve the above object, the present invention comprises a male rotor and a female rotor composed of a rotor main body and a shaft, and each of the male and female rotors is made of titanium. When manufacturing each rotor body with titanium alloy, manufacture each shaft of male and female rotors with ferrite steel, and manufacture each rotor body with plastic when manufacturing each rotor body with titanium alloy. In this case, each of the shafts is made of ferrite steel, and the rotor body and the shaft of the male rotor and the rotor body and the shaft of the female rotor are integrally formed.

[Effect] Even if the rotor body and the shaft are made of different materials such that the rotor body is made of a titanium alloy and the shaft is made of ferrite steel, or the rotor body is made of plastic and the shaft is made of ferrite steel, the heat generated between the two members is different. Because of the small expansion difference, the difference in elongation between the male and female rotors is small. Therefore, the gap between the male rotor and the female rotor can be kept constant during operation, and welding caused by contact can be eliminated. If the rotor body is made of a titanium alloy or plastic, these can be reduced in weight because of their low specific gravity.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of a rotor according to the present invention, in which a male rotor 2 and a female rotor 3 are arranged in parallel and engaged with each other, and both rotors 2 and 3 are rotated in opposite directions.
In a configuration in which the air taken in between two or three can be compressed and taken out, the male rotor 2 and the female rotor 3
In each case, the rotor bodies 2a, 3a and the shafts 2b, 3b are separate bodies,
The rotor bodies 2a and 3a are made of a titanium alloy, the shafts 2b and 3b are made of ferritic steel, and the rotor bodies 2a and 3a and the shafts 2b and 3b are shrink-fitted and integrated by press-fitting or bonding. Looking at the linear expansion coefficients of both, titanium alloy: about 9 to 11 × 10 ⁻⁶ 1 / ° C. ferritic steel: about 11 to 13 × 10 ⁻⁶ 1 / ° C. Therefore, when the rotor bodies 2a and 3a are made of a titanium alloy, the difference in thermal expansion during operation can be minimized by using ferrite steel having the linear expansion coefficient closest to the titanium alloy. . Further, by making the rotor bodies 2a and 3a made of plastic, the difference in thermal expansion between the male rotor 2 and the female rotor 3 can be minimized. That is, the difference in thermal expansion of plastic is generally larger than that of aluminum alloy, but can be controlled in the range of 10 to 100 × 10 ⁻⁶ 1 / ° C. depending on the contained components. Therefore, the difference in elongation between the rotors can be minimized by, for example, making the female rotor 3 made of plastic.

[Effects of the Invention] As described above, according to the rotor of the screw type supercharger or the compressor of the present invention, when the rotor body is made of a titanium alloy together with the male rotor and the female rotor, the shaft is made of ferrite steel. In addition, when the rotor body is made of plastic, the shaft is made of ferrite steel and the rotor body and the shaft are manufactured separately, so that the entire body can be made lightweight and mounted on an automobile. Advantageously, there is little difference in thermal expansion between the rotor body and the shaft, so that the difference in extension between the male and female rotors during operation can be minimized to reduce the gap between the two rotors. It can be prevented from becoming too small and eventually coming into contact and fusing.In particular, the shaft made of ferritic steel allows the ferrite steel to expand linearly due to austenitic steel. Since the coefficient is small, the elongation of the shaft during operation is smaller than that of austenitic steel, and therefore, the difference in thermal expansion between the bearing supporting both ends of the shaft can be reduced. Since the clearance can be maintained, the bearing surface pressure can be maintained, and troubles such as seizure are less likely to occur.

[Brief description of the drawings]

FIG. 1 is a partially cut plan view of the rotor of the present invention, FIG. 2 is a front view schematically showing a screw type supercharger, FIG. 3 is a plan view of the rotor shown in FIG. 2, and FIG. FIG. 4 is a schematic plan view showing a difference in extension between a rotor and a female rotor. 2 ... male rotor, 3 ... female rotor, 2a, 3a ... rotor body, 2b,
3b ... axis.

Claims (1)

(57) [Scope of request for utility model registration] A male rotor and a female rotor comprising a rotor body and a shaft are provided. Each of the male and female rotor bodies is made of a titanium alloy or plastic, and each of the rotor bodies is made of a titanium alloy. When manufacturing, each shaft of the male rotor and the female rotor is made of ferrite steel, and also when each of the rotor bodies is made of plastic, each shaft is made of ferrite steel, and the male rotor and the rotor body are manufactured. And a shaft of the screw type supercharger or the compressor, wherein the rotor body and the shaft of the female rotor are integrated with each other.