JPH0267488A - Screw type supercharger - Google Patents

Abstract

PURPOSE:To make any possible deposition preventable by varying each hardness of both male and female screw rotors, and also varying a grade of hardness in a casing part proximate to each of these male and female screw rotors for formation. CONSTITUTION:A pair of male-female screw rotors 3, 4 engaging with each other via a fine clearance are housed in a rotor chamber 2 of a casing 1 whose one side is opened in a suction port and the other in a discharge port respectively, and these rotors are formed so as to be synchronously rotated via timing gears 5, 6 and to be driven via speed-up gears 7, 8. The casing 1 and these male and female rotors 3, 4 are all formed with an aluminum material, while each hardness of these rotors 3, 4 is varied to some extent and what is more, it is formed in varying hardness between these rotors 3, 4 and a part of the casing 1 proximate to each of them. Consequently, even in an interval between the same aluminum members, deposition is made preventable in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a screw type supercharger used for example in automobiles.

(Prior Art) Conventionally, a screw type supercharger using a screw rotor is known (Japanese Patent Laid-Open No. 51-37316).

This supercharger has a structure similar to that of a conventionally well-known screw compressor, and the rotor chamber of the casing has one opening at the suction port and the other at the discharge port, and the two mesh with each other through a small gap. It is formed by rotatably housing a pair of male and female screw rotors. Unlike an oil-cooled compressor, oil is sprayed into the rotor chamber to cool the rotor chamber, and lubricate and seal between the two rotors in the rotor chamber. It is non-contact and is formed to rotate synchronously via a synchronous gear.

By the way, since this supercharger is an oil-free type, the discharge temperature is generally high (150℃ to 30℃).
0°C), the thermal expansion of the rotor is large.

On the other hand, in order to improve the performance of the supercharger, the rotor chamber 1 after thermal expansion is
Although it is preferable that the gap between the two rotors be as small as possible, it is necessary to prevent the two rotors from coming into contact with each other.

To meet such requirements, it is conceivable to apply a coating to the surface of the iron rotor, as in the case of screw compressors.

However, one of the most important issues for a supercharger installed in a car, for example, is to reduce its weight, and to achieve this weight reduction, an Al (aluminum) casing and screw rotor are used. .

(Problems to be Solved by the Invention) As mentioned above, in the case of a supercharger using an Al casing and a screw rotor, even if the rotor is coated, the screw rotors may be damaged due to thermal expansion. Experiments have confirmed that even the slightest contact with the casing causes welding between the AI members. That is, there is a problem in that a rotor made of Al is much more likely to be welded than a rotor made of iron.

For example, as shown in FIG. 2, a male rotor 11 and a female rotor 1
2, when the male rotor l! The A1 member 13 of is hollowed out, and the hollowed out A1 member 13 sticks to the surface of the female rotor 12.

The present invention has been made to address these conventional problems, and aims to provide a screw type supercharger that can prevent welding.

(Means for Solving the Problems) In order to achieve the above problems, the present invention provides a rotor chamber of a casing which has one side opened to the suction port and the other side opened to the discharge port.
In a screw type supercharger in which a pair of male and female screw rotors that mesh with each other through a minute gap are rotatably housed and formed to rotate synchronously via a synchronous gear, the casing and the female and male screw rotors are made of aluminum. The hardness of the female and male screw rotors is different, and the hardness of the female and male screw rotors and the casing portions adjacent to each of them is made different.

(Example) Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a screw type supercharger according to the present invention, in which, similarly to the above, the casing 1 is opened to the suction port on one side and the discharge port is opened on the other side in the rotor chamber 2 of the casing 1, which mesh with each other through a small gap. A pair of male and female screw rotors 3.4 are housed therein and are configured to rotate synchronously via a synchronous gear 5.6 and to be driven via a speed increasing gear 7.8. The casing 1 and the female and male rotors 3.4 are made of Al material, and the hardness of the female and male rotors 3.4 is made different, and the portions of the casing 1 that are close to the female and male rotors 3.4 and each of them are They are formed with different hardnesses.

For example, while increasing the hardness of the surface of the male rotor 4 by, for example, hard alumite treatment, the female rotor 3 and the casing 1
and remain as normal A1 members, and the material between them is the same.

Furthermore, in order to create a difference in hardness overall, the hardness of the male rotor 4 is increased, the female rotor 3 is made of the normal material, and the portion of the casing 1 adjacent to the male rotor 4 is made of the normal material. , the hardness of the portion adjacent to the female rotor 3 may be increased.

In addition, as another combination, the male rotor 4 is made of a normal material, the hardness of the female rotor 3 is increased, the hardness of the part of the casing 1 that is close to the male rotor 4 is increased, and the part that is close to the female rotor 3 is made of a normal material. The present invention is not limited to the above combinations.

Next, Table 1 shows specific examples of combinations of materials and degrees of 1iiiI.

Table 1 (* indicates that it is made by sand molding, and the others are made by molding.) (Effects of the invention) As is clear from the above explanation, the present invention has a casing with one side open to the suction port and the other side to the discharge port. In a screw type supercharger, a pair of male and female screw rotors that mesh with each other through a minute gap are rotatably housed in a rotor chamber, and are configured to rotate synchronously via a synchronous gear. The screw rotor is made of an AI material, and the female and male screw rotors have different hardnesses, and the hardness of the female and male screw rotors and the casing portions adjacent to each of them are made to be equal in hardness.

Therefore, it is possible to prevent welding even between the same AI members.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a screw type supercharger according to the present invention, and FIG. 2 is a partial sectional view showing a welded state. l...Casing, 2...Rotor chamber, 3...Female rotor. 4... Male rotor, 5.6... Synchronous gear. Patent Applicant Kobe Steel Co., Ltd. Agent Patent Attorney Aoyama Aoyama and 1 other person Figure 1 Figure 23

Claims (1)

[Claims] (1) A pair of male and female screw rotors that mesh with each other through a small gap are rotatably housed in the rotor chamber of the casing, one opening at the suction port and the other at the discharge port, and rotate synchronously via synchronous gears. In the screw type supercharger formed as described above, the casing and the female and male screw rotors are formed of Al material, and the hardness of the female and male screw rotors is made different, and each of the female and male screw rotors is made of Al material. A screw type supercharger characterized in that adjacent casing parts are formed with different hardnesses.