JPS61112792A - Cocoon-shaped rotor for roots type fluid conveyance machine - Google Patents

Abstract

PURPOSE:To enable efficient conveyance by enlarging sealing area against the inner side of a housing at both ends of a rotor. CONSTITUTION:Blocking members 46, 56 to block openings of hollow sections 44 are fixed to both ends of a rotor 40. And both ends of the sealed rotor 40 are covered almost over with layers of resin 52. With this constitution, sealing area against the inner side of a housing at both ends of the rotor 40 becomes large to improve cubage efficiency so that efficient conveyance can be done. Furthermore, masking to cover opening of the hollow sections becomes unnecessary coating in the case of applying resin, as the openings of the hollow sections are covered by the blocking members 46, 56.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a cocoon-shaped rotor used in a roots-type fluid feeder, and particularly relates to an improvement in the structure of both ends of the rotor.

A type of cocoon-shaped rotor used in Roots-type fluid feeders such as Roots-type superchargers, blowers, compressors, pumps, etc., has a resin layer on the outer peripheral surface of the cocoon-shaped rotor. Some rotors have cavities formed inside the rotor that are symmetrical with respect to the center line of rotation and open at both end surfaces of the rotor.

According to such a cocoon-shaped rotor, the mutual interference between the rotors is absorbed by the resin layer on the outer peripheral surface, so the clearance between the rotors can be made as small as possible and the feeding efficiency can be increased. The hollow portion formed inside the rotor has the advantage of reducing the weight of the rotor and the rotational inertia mass.

When the sun reaches 7, +9 digits, such cocoon-shaped rotors are generally housed in pairs in a housing, and are rotated in opposite directions at different rotational phases to supply fluid. However, since the cavity is open on both end faces of the rotor, the sealing area between the inner surface of the housing and both ends of the rotor is small, which is disadvantageous in preventing fluid leakage, and the volumetric efficiency and feed rate are reduced. There was a problem that a sufficient reflux ratio could not be obtained.

In addition, when an axial force is applied due to thermal deformation, etc., the rotor end face may come into contact with the inner surface of the housing, but the contact area is small due to the opening of the cavity, and therefore the contact pressure at the time of contact becomes large. There is also the disadvantage that the wear on both open end surfaces of the rotor (normally, the open end surfaces are also covered with resin, so the resin wears out) increases.

Furthermore, when coating the outer peripheral surface of such a cocoon-shaped rotor with a resin layer, it is necessary to attach complex masking members to both ends of the rotor in order to prevent the resin from adhering to the cavity. However, there was also the problem that masking was troublesome.

The present invention was made in order to solve the above-mentioned problems of the conventional art. A closing member is fixed to each of the openings of the cavity, and substantially the entire surfaces of both ends of the rotor which are closed as a result are covered with a resin layer.

By doing this, the sealing area of both ends of the rotor against the inner surface of the housing becomes larger (because it becomes larger, the volumetric efficiency improves,
Efficient feeding can be performed.

Moreover, even if both ends of the rotor come into contact with the inner surface of the housing, since the contact area at the time of contact is large, the surface pressure is reduced, and it is possible to reduce wear on the resin layer. Furthermore, since the opening of the cavity is covered with a closing member,
This has the advantage of eliminating the need for troublesome masking to cover the opening of the cavity when coating with resin.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIGS. 1 and 2 are a front sectional view and a side sectional view of a roots-type supercharger 10 for a vehicle, which is a type of roots-type fluid feeder. In the figure, reference numeral 12 denotes a cylindrical housing body, and its openings at both ends are closed by end brakes 1-1 and 16, respectively, thereby forming a housing 19 having an airtight rotor chamber 18 inside. ing. A pair of cocoon-shaped rotors 20 and 22 are provided within the rotor chamber 18 so as to be rotatable around mutually parallel axes. Cocoon-shaped rotors 20 and 22 have both ends fixed to rotating shafts 24 and 26, which are rotatably supported by end plates 14 and 16 via hair rings, respectively.

A V-pulley 28 is fixed to one end of the rotating shaft 24,
The rotational force transmitted from a drive source such as an engine (not shown) via the belt 30 is transmitted to the timing gears 32 and 3 fixed to the other ends of the rotating shafts 24 and 26 that mesh with each other.
4 to the other rotating shaft 26. The timing gears 32 and 34 have the same number of teeth, so that the cocoon-shaped rotors 20 and 22 are rotated in opposite directions at the same speed. Cocoon-shaped rotor 2
0 and 22 are rotated, for example, in the direction shown by the arrow in FIG. 2, the air-fuel mixture sucked in from the intake port 36 is forced to be sent to the engine via the discharge port 38.

Since the eyebrow-shaped rotors 20 and 22 have similar configurations,
The eyebrow-shaped rotor 20 will be explained below.

As shown in FIG. 3, the cocoon-shaped rotor 20 includes a rotor body 40 made of metal such as iron or aluminum alloy. ff142 is formed. This resin layer 42 is usually formed with a thickness of about 0.3 to 0.5 m+e, and is made of a resin that is a copolymer of tetrafluoroethylene and ethylene, for example.

At the center of the rotor body 40 is a rotating shaft 24 of the supercharger 10.
A shaft hole 43 for fitting is formed therethrough. In addition, a hollow portion 44 is formed in each of the pair of cocoon-shaped blade portions of the rotor body 40 to reduce weight and rotational inertia mass. These cavities 44 are formed symmetrically across the rotation center line of the rotor body 40 (the center line of the shaft hole 43), and extend through the rotor body 40 in a direction parallel to the center line. , each of which has an opening on both end faces.

As is clear from FIG. 4, the openings on both sides of the cavity 44 are connected to four closing plates 46 as closing members.
Each is blocked by

These closing plates 46 are connected to the cavity 1) 4 from the outer periphery.
The hollow portion 44 is provided with a low annular flange portion 48 that protrudes along the inner peripheral surface of the flange portion 48 .
are press-fitted into the respective openings. Further, the outer surface of each closing plate 46 is flush with the opening peripheral portion of the cavity 44 (the end surface of the rotor body 40), and these closing plates 46 are connected to the rotor 20 together with the rotor body 40.
The rotor 20 has end faces perpendicular to its rotation center line at both ends. Note that each of the closing plates 46 is formed with a communication hole 50 that communicates the cavity 44 with the outside, so that air thermally expanded within the cavity 44 can escape to the outside.

Then, both ends of the rotor 20 closed as described above, that is, the outer surface of each closing plate 46 and the end surface of the rotor body 40 connected thereto, the openings at both ends of the shaft hole 43, and the entire surface except for each communication hole 50. are respectively covered with a resin layer 52.

These resin layers 52 are similar to the resin layer 42 formed on the outer circumferential surface of the rotor body 40, and are formed by a known resin fixing method, such as a fluidized dipping method, an electrostatic coating method, or other appropriate method. It was formed.

Therefore, according to the cocoon-shaped rotor 20 as described above, the first
End plates 14 and 1 of the housing 19 shown in the figure
The sealing area between the inner surface of the rotor 6 and both end faces of the rotor 20 is sufficiently wide compared to the conventional one in which the cavity 44 is open at both ends, and the resin J'#52 on both end faces makes it possible to prevent sliding. Since the clearance can also be reduced, sealing performance is improved and volumetric efficiency is increased. Moreover, even if both end surfaces of the rotor 20 contact the end plates 14 or 16, the contact pressure is low because the contact surfaces are wide, and the resin layer 52 is less abraded.

In addition, since the openings on both sides of the cavity 44 are originally designed to be closed, the shaft hole 43 and the communication hole 5 are
It is sufficient to mask only 0.

From a different perspective, it can be said that the closing plate 46 functions as a masking member in the first place, but unlike conventional ones, the closing plate 46 is fixed and used to form both end surfaces of the rotor. It can be said that there is a certain philosophy.

Note that the rotor body 40 and each of the closing plates 46 may be made of materials with the same or different coefficients of thermal expansion; By selecting the material, it is also possible to change the apparent coefficient of thermal expansion in the eyebrow contour shape of the rotor 20 compared to the case of the rotor body 40 alone. For example, each closing plate 46 is fixed to the rotor body 40 by welding or the like, and the material of the block plate 46 is fixed to the rotor body 40 by welding.
If a material with a coefficient of thermal expansion smaller than that of 0 is used, the above-mentioned apparent coefficient of thermal expansion becomes smaller.

As another example, as shown in FIGS. 5 and 6, a plurality of labyrinth grooves 54 (which are connected like a brush stroke) are formed on the surface of the resin layer 52 at both ends of the rotor 20. ) can also be provided. These labyrinth grooves 54 are preferably formed along the longitudinal direction of the eyebrow shape.
If this is provided, the above-mentioned sealing effect can be further enhanced.

In addition, as shown in FIG. 7, a simple plate-shaped block plate, -
It is also possible to fit the hole 46 into the opening of the cavity 44 and fix it there by welding rather than press fitting.

Further, as shown in FIG. 8, on both end surfaces of the rotor body 40, there are closed plates 56 having a shape corresponding to the cocoon-shaped outline of the rotor body 40.
are fixed by welding or other appropriate fixing means, and the openings on both sides of each cavity 44 are closed by the closing plates 56, and the aforementioned resin layer is applied over almost the entire outer surface of the closing plates 56. 52 can also be formed. If you do this, the occlusion plate will be 2
It is also possible to fix the resin layer 52 to both ends of the rotor body 40 in advance.

Although not illustrated in detail, the present invention can be implemented with various modifications based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

1 and 2 are a front sectional view and a side sectional view showing a roots-type supercharger including a cocoon-shaped rotor, which is an embodiment of the present invention. FIG. 3 is a cross-sectional view of the cocoon-shaped rotor, and FIG. 4 is a longitudinal cross-sectional view. FIG. 5 is a partial side view of a cocoon-shaped rotor according to another embodiment, and FIG. 6 is a sectional view taken along the line -■ in FIG. FIGS. 7 and 8 are partial cross-sectional views showing other embodiments of the present invention, respectively. 10: Roots type supercharger (Roots type fluid feeder) 19: Housing 20. 22: Cocoon-shaped rotor 40: Rotor body 42: Resin layer 44: Cavity part

Claims (2)

[Claims] (1) A resin layer is formed on the outer peripheral surface of a cocoon-shaped rotor, and symmetrical cavities are formed inside the rotor with the rotation center line in between, opening at both end surfaces of the rotor. In the cocoon-shaped rotor, closing members for closing the opening of the cavity are fixed to both ends of the rotor, and substantially the entire surfaces of the closed ends of the rotor are covered with a resin layer. The eyebrow-shaped rotor is characterized by (2) A resin layer covering almost the entire surface of both ends of the rotor,
The cocoon-shaped rotor according to claim 1, which has a plurality of labyrinth grooves along the longitudinal direction of the cocoon-shaped rotor on its surface.