JPH0510282A - Supercharger - Google Patents

Abstract

PURPOSE:To lighten a device, and reduce clearances between each rotor and between rotors and a housing to obtain a supercharger having a high discharge efficiency by adjusting a coefficient of linear expansion at a specified value, and making rotors of the resin composition having a glass-transition temperature at a specified degree or more. CONSTITUTION:As the resin composition for the material of rotors 4, 4 and screw rotors 14, 15, thermoplastic synthetic resin, which is mixed with inorganic or organic filling material and addition material to adjust a coefficient of linear expansion at 1.7E-5-2.7E-5/ deg.C and which has a glass-transition temperature at 140 deg.C or more and to which injection molding is applicable, is used. In ordinary, since aluminum alloy is used as the material of a housing 3 and 13, clearances between the housing and the rotors or between the screw rotors or between the rotors are maintained constant at the time of temperature rise with the operation. It is effective for preventing the collision to set the coefficient of linear expansion at the same degree with aluminium alloy, namely, at 1.7E-5-2.7E-5/ deg.C by the blending of the filling material and the addition material, and the discharge efficiency is improved by setting the initial clearance at 0.1mm or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roots-type or screw-type supercharger used for, for example, an automobile, and more particularly to improvement of a rotor.

[0002]

2. Description of the Related Art As a supercharger arranged in an intake system of an internal combustion engine, there are a roots supercharger and a screw type supercharger. As shown in FIGS. 1 and 2, the former roots supercharger has a pair of rotors 4 and 4 housed in a housing 3 serving as a cylinder having a suction port 1 and a discharge port 2 so as to rotate in mesh with each other. The rotors 4 and 4 are synchronously driven with a minute gap between the rotors 4 and 4 and the housing 3.

The latter screw type turbocharger is shown in FIGS.
As shown in FIG. 1, one is the suction port 11 and the other is the discharge port 12.
A pair of male and female screw rotors 1 meshing with each other in a rotor chamber of a housing 13 opened to the outside through a minute gap.
4 and 15 are rotatably housed. The rotors 14 and 15 are not in contact with each other, and are synchronously rotated via the synchronous gear 16.

By the way, what is important for a supercharger applied to an automobile is to keep the increase in vehicle weight to a minimum, and to rapidly accelerate and decelerate the automobile. As a result, it is necessary to reduce the weight of the rotor.

In response to these demands, the conventional supercharger has
Aluminum alloy has been widely used as a main constituent material of the rotors 4 and 4, the screw rotors 14 and 15, and the housings 3 and 13.

Further, in order to reduce the above-mentioned gap and improve pump efficiency, resin coating is applied to the outer peripheral surfaces of the rotors 4 and 4 and the screw rotors 14 and 15, for example, Japanese Utility Model Laid-Open No. 59-174389. JP-A-60-
It is known from Japanese Patent No. 173387, Japanese Patent Laid-Open No. 63-21380, etc., but as described above, since the main constituent material is an aluminum alloy, there is a limit to the weight reduction of the supercharger.

In order to reduce the weight of the supercharger, one of the methods is to make the main part resin, but it is disclosed in JP-A-60-561.
As is known in Japanese Patent No. 91, it is the current situation that a resin coating rotor is provided with a metal coating layer on the surface of the resin because it has poor heat resistance and causes thermal deformation.

[0008]

As described above, in order to provide the metal coating layer on the surface of the resin rotor, an extra treatment step is required, resulting in an increase in cost, and even if the metal coating layer is provided. However, it is difficult to sufficiently improve the heat resistance of the resin, and there is a problem that the thermal deformation of the rotor cannot be prevented.

Therefore, the present invention solves the above problems and provides a supercharger that is lightweight and has a high discharge efficiency by using a resin rotor having excellent heat resistance and free from thermal deformation. It is an issue.

[0010]

In order to solve the above problems, the present invention is directed to a supercharger including a plurality of rotors that rotate in mesh with each other in a housing, wherein the rotors have a linear expansion coefficient. Is 1.7E-5 to 2.7E-5
The composition is composed of an injection-moldable resin composition in which an inorganic or organic filler and an additive are mixed so that the temperature becomes / ° C.

The resin composition used to form the rotor has a structure composed of a resin having a glass transition temperature of 140 ° C. or higher.

The resin composition which can be injection-molded and has a glass transition temperature of 140 ° C. or higher includes thermoplastic polyimide, polyetheretherketone (PEEK),
Examples include polyether ketone (PEK), polyether nitrile (PEN), polyether sulfone (PES), polyamide imide (PAI), polythioether sulfone (PTES), and the like.

[0013]

By adjusting the linear expansion coefficient of the resin composition used for injection molding of the rotor to 1.7E-5 to 2.7E-5 / ° C., the linear expansion coefficient of the aluminum alloy forming the housing becomes approximately the same. As a result, the initial clearances between the rotors and between the rotor and the housing can be reduced, and the pump efficiency is improved.

Since the rotor undergoes adiabatic compression under high speed rotation, the temperature of the atmosphere may reach about 140 ° C., but the resin composition forming the rotor has a glass transition temperature of 1 ° C.
Since a resin of 40 ° C or higher is used, static mechanical strength and dynamic viscoelasticity do not drop significantly in the operating temperature range.
It is possible to prevent deformation of the rotor under high temperature and high speed.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, the roots supercharger is constructed by housing a pair of rotors 4 and 4 inside a housing 3 so as to rotate in mesh with each other. As shown in FIGS. 3 and 4, the feeder is configured such that a pair of screw rotors 14 and 15 are housed in a housing 13 so as to be engaged with each other and rotate.

In the above supercharger, the housing 3,
13 is formed of, for example, an aluminum alloy, and the rotors 4 and 4 and the screw rotors 14 and 15 are formed of a resin composition by injection molding.

The rotors 4, 4 and the screw rotor 14,
The resin composition used for the constituent material of No. 15 has a coefficient of linear expansion adjusted to 1.7E-5 to 2.7E-5 / ° C by mixing an inorganic or organic filler and an additive, and has a glass transition. It is made of an injection-moldable thermoplastic synthetic resin having a temperature of 140 ° C. or higher.

The supercharger of the present invention is constructed as described above, and the rotors 4, 4 of the supercharger or the screw rotor 14,
At 15, since the adiabatic compression is repeated, the temperature of the atmosphere may be about 140 ° C. Although the materials for the rotors 4 and 4 or the screw rotors 14 and 15 are required to have heat resistance capable of withstanding such temperatures, according to the present invention, a material having a high glass transition temperature is used. In the above, the static mechanical strength and the dynamic viscoelasticity are not significantly reduced, and the deformation of the rotors 4 and 4 and the screw rotors 14 and 15 under high temperature and high speed rotation can be prevented. Further, in consideration of the recent high speed rotation, the temperature may rise further, so that the glass transition temperature is preferably 200 ° C. or higher.

Further, since aluminum alloy is usually used as the material of the housings 3 and 13, a gap between the housing 3 or 13 and the rotors 4 and 4 or the screw rotors 14 and 15 and between the rotors when the temperature is raised by the operation. In order to keep the temperature constant or to avoid collision, it is necessary to make the linear expansion coefficient approximately the same as that of the aluminum alloy by blending the filler and the additive, that is, 1.7E-5 to 2.7E-5 / ° C. This is effective, and the initial gap is conventionally 0.
It was necessary to have 5 mm or more, but it is possible to increase the ejection efficiency by making it 0.1 mm or less. Furthermore, since the resin has a linear expansion coefficient that changes around the glass transition temperature, it is effective that the resin does not have a glass transition temperature in the operating temperature range, that is, a glass transition temperature of 140 ° C. or higher.

[Specific Example] NEW-TPI (thermoplastic polyimide, glass transition temperature 240 ° C.) 65w manufactured by Mitsui Toatsu Co., Ltd.
%, Glass flakes (100 microns, Nippon Sheet Glass) 3
The rotor and the steel shaft are integrally molded by insert injection molding into pellets by mixing 5 w% with a Henschel mixer. The linear expansion coefficient of the material with this blend is 0
It was 2.2E-5 / ° C at 240 ° C. The specific gravity is 1.58, and the weight can be reduced by 40% compared with the aluminum alloy.

By incorporating this into a supercharger, an initial clearance of 0.1
As a result of operating for 1 hour at 10,000 rpm at 10,000 rpm, there was no deformation or dimensional change of the rotor and it was good.

[0023]

As described above, according to the present invention, a resin composition having a linear expansion coefficient of 1.7E-5 to 2.7E-5 / ° C. and a glass transition temperature of 140 ° C. or higher is used. Since the rotor is formed, the supercharger can be made lighter and
It is possible to reduce the gaps between the rotors and between the rotors and the housing, which makes it possible to obtain a supercharger with high discharge efficiency.

Further, since the rotor can be formed by injection molding, the manufacturing process of the rotor is simplified, which is advantageous in terms of cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a roots supercharger.

FIG. 2 is a vertical sectional side view of the above.

FIG. 3 is a vertical sectional side view of the screw type turbocharger.

FIG. 4 is a vertical sectional front view of the same.

[Explanation of symbols]

1 suction port 2 outlet 3 housing 4 rotor 11 Suction port 12 outlets 13 housing 14, 15 screw rotor 16 Synchronous gear

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location F04C 29/00 D 8608-3H

Claims (4)

[Claims] 1. A supercharger comprising a plurality of rotors rotating in mesh with each other in a housing, wherein the rotors have a coefficient of linear expansion of 1.7E-5 to 2.7E-5 / ° C. A supercharger comprising an injection-moldable resin composition containing an inorganic or organic filler and an additive. 2. The supercharger according to claim 1, wherein the resin composition is composed of a resin having a glass transition temperature of 140 ° C. or higher. 3. The supercharger according to claim 1, wherein the plurality of rotors are of a roots type. 4. The supercharger according to claim 1, wherein the plurality of rotors are of a screw type.