JPH08284856A - Rotor and formation thereof - Google Patents

Abstract

PURPOSE: To provide a rotor that is lighter in weight, small in a moment of inertia and low cost of production. CONSTITUTION: This rotor is equipped with an engaging part 7 with the counterpart side rotor, a rotor body 3 with a bottom part 9 making a form to be circumscribed with a cylinder or its one part, and a rotor shaft 5 being fitted in the bottom part 9 and subject to spot welding, while the engaging part 7 and the bottom part 9 are integrally formed as one body with a plate member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor used in, for example, a screw type compressor and a molding method thereof.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 5-195701 discloses a "screw rotor and its manufacturing method". FIG. 9 shows a male screw rotor 2 manufactured by this manufacturing method.
01 is shown.

Since a screw type air compressor is used for a supercharger of a vehicle and rotates at a high speed, if the inertia moment of the screw rotor is large, the response when the vehicle accelerates is poor. Also, the engine and the supercharger are connected and disconnected by an electromagnetic clutch or the like, but in order to prevent slippage when connecting with the engine, the electromagnetic clutch must be made larger as the moment of inertia of the screw rotor is larger. Furthermore, if the moment of inertia is large, the rotor 201 may come into contact with the mating female rotor during rapid acceleration or deceleration, and the coating on the surface of each rotor may peel off.

The rotor is composed of a rotor shaft and a rotor body. Generally, the rotor shaft is made of solid steel, and the rotor body is made of aluminum for weight reduction.
When the rotor body is made of solid aluminum, the rotor is heavy, and the inertia moment of the rotor is increased accordingly. When the rotor body is made of aluminum, thermal expansion easily causes contact with the mating rotor.

The problem of the moment of inertia is particularly great in the male screw rotor 201, which has a thicker tooth and a heavier weight than the female screw rotor and has a small number of teeth and a large number of revolutions.

Therefore, in the screw rotor 201 of FIG. 9, the meshing portion 203 is made hollow to reduce the weight and the moment of inertia, thereby improving the response at the time of acceleration, downsizing the clutch, and performing rapid acceleration / deceleration. It prevents contact between the rotors.

[0007]

However, the screw rotor 201 has a structure in which thin plates 205 and 207 are twisted in a screw shape and stacked, and the thin plates 205 and 207 after stacking are stacked.
207 is a hollow hole 209 filled with ceramic powder,
They are integrally joined by applying high temperature and high pressure in a pressure vessel containing a heating furnace.

[0008] As described above, since the number of man-hours required for stacking and integrating is high, the cost is high, and the meshing portion 20 is joined.
Since the surface of 3 has unevenness due to the twisting of the thin plates 205 and 207, it must be smoothed, but it is difficult to process the tooth-shaped surface smoothly, and it is necessary to apply a thick coating to the desired teeth. The surface shape cannot be obtained, which increases the cost. Further, each thin plate 20 is pressed at the time of pressing.
If the burrs that occur on the entire periphery of 5, 207 are not removed, the axial length of the screw rotor 201 will not be uniform, and the deburring operation will further increase the cost.

Therefore, an object of the present invention is to provide a rotor that is lightweight, has a small moment of inertia, and is low in cost, and a method for molding the rotor.

[0010]

A rotor according to a first aspect of the present invention includes a rotor body having a meshing portion with a mating rotor and a bottom portion having a shape circumscribing a cylinder or a part thereof, and a rotor body fitted into the bottom portion. And a rotor shaft fixedly fixed, and the meshing portion and the bottom portion are integrally formed of a plate material.

The rotor of claim 2 is the rotor of claim 1 in which the rotor shaft is hollow.

The rotor of claim 3 is the rotor of claim 2 in which the bottom portion of the rotor body is spot-welded to the rotor shaft.

The rotor according to claim 4 is the rotor according to claim 1, 2 or 3 in which the bottom portion of the rotor main body is formed thicker than other portions.

The method of molding the rotor of claim 5 is a method of molding the rotor of claim 1, 2, 3 or 4, wherein the pipe-shaped raw material placed inside the female mold is pressurized and expanded from the inside. The rotor body is formed by molding.

A rotor molding method according to claim 6 is a method for molding the rotor according to claim 1, 2, 3 or 4, wherein the pipe-shaped raw material disposed inside the female mold is pressurized and expanded from the inside. It is characterized in that the rotor main body and the rotor shaft are respectively molded and integrated.

[0016]

In the rotor of claims 1 to 4, since the meshing portion with the mating rotor and the bottom portion into which the rotor shaft is fitted and fixed are integrally formed of a plate material, unlike the conventional example of FIG. Deburring of plates, stacking of plates, joining of plates, surface processing, etc. are not required, and the cost is greatly reduced in terms of material cost and processing cost, and it is extremely lightweight and has a small moment of inertia, Little expansion.

Therefore, in the vehicle using the compressor using the rotor as the supercharger, the response at the time of acceleration is significantly improved, and the clutch for connecting / disconnecting with the engine can be downsized. In addition, the rotor's moment of inertia is small and contact between rotors is prevented even during rapid acceleration / deceleration.
Since there is no contact between the rotors due to thermal expansion, the coating on each rotor surface can be thin or even eliminated.

According to a second aspect of the present invention, in the rotor of the first aspect, the rotor shaft is hollow, and the moment of inertia of the rotor is further reduced.

The rotor of claim 3 utilizes the fact that both the rotor body and the rotor shaft of the rotor of claim 2 are hollow, and these are integrated by spot welding. And can be firmly integrated at low cost.

The rotor of claim 4 is the rotor of claim 1, 2 or 3.
In this rotor, the bottom portion of the rotor body is formed thicker than other portions, the strength of the bottom portion is increased, and the joint portion with the rotor shaft is strengthened, so that the rotor can bear a large amount of torque.

The method of molding the rotor of claim 5 is a method of molding the rotor of claim 1, 2, 3 or 4, wherein the pipe-shaped raw material placed inside the female mold is pressurized and expanded from the inside. The rotor main body is formed by using this method, which is a method with extremely high productivity and low cost as compared with the conventional example.
Further, by using a long pipe as a raw material and cutting the molded product into a required length, it is possible to process a large number of rotor bodies at one time. In this case, the productivity is further enhanced, The cost will be further reduced.

According to this method, the rotor body according to claim 4 can be easily obtained by plastically deforming the pipe-shaped raw material.

The method of molding the rotor of claim 6 is the method of molding the rotor of claim 1, 2, 3 or 4, wherein the pipe-shaped raw material placed inside the female mold is pressurized and expanded from the inside. The rotor main body and the rotor shaft are respectively formed by molding the rotor main body and the rotor shaft, and the productivity is high and the cost is low as compared with the conventional example. It is possible to process a large number of rotors at once by using long pipes for each of the raw materials, cutting the molded product to the required length, and integrating it. In this case, productivity is improved. It will be higher and the cost will be lower. Further, in molding the rotor body, the rotor body of claim 4 can be easily obtained as in the case of claim 5.

In the rotors according to claims 1 to 4 and the rotors molded by the methods according to claims 5 and 6, the former has a hollow rotor body, and the latter has a hollow rotor body and a rotor shaft. Various methods can be used for joining the rotor body and the rotor shaft. For example, spot welding, other welding, brazing, etc. are suitable. Alternatively, since the rotor body has a sufficiently small moment of inertia, the rotor shaft may be simply press-fitted into the rotor body, or they may be adhered after the press-fitting. Press-fitting and bonding are particularly advantageous when the rotor shaft is solid.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1, 2, and 3, this embodiment is a male screw rotor 1 used in a screw type air compressor. This screw type air compressor is used in a vehicle supercharger. or,
4, 5, 6, 7, and 8 show a molding process of the screw rotor 1 according to the method of claim 6.

The left and right directions are the left and right directions in FIGS. 1 and 3, and members and the like without reference numerals are not shown.

The supercharger is composed of an input pulley, a speed increasing gear set, a timing gear set, a screw type air compressor and the like.

The screw type air compressor includes a male screw rotor 1 and a female screw rotor (counter rotor). Male screw rotor 1
As shown in FIGS. 1, 2, and 3, is composed of a hollow rotor main body 3 and a rotor shaft 5. The rotor main body 3 has a meshing portion 7 with a female screw rotor, a bottom portion 9, left and right side plate members. It is composed of 11, 13 and the like.

The meshing portion 7 and the bottom portion 9 are, as described later,
As shown in FIG. 2, it is integrally formed of a plate material, and the plate thickness of the bottom portion 9 is a, the tooth root portion 15 and the tooth tip portion 17 of the meshing portion 7 are
If the plate thicknesses of b and c are respectively, a>b> c,
Thus, the plate thickness a of the bottom portion 9 is the plate thicknesses b and c of the meshing portion 7.
In addition to being formed thicker, the plate thickness of the meshing portion 7 is formed so as to gradually decrease from the tooth root portion 15 to the tooth tip portion 17. The thinnest portion (thickness c) is 2 mm to 3 mm.

The rotor shaft 5 has a shaft body 19
And left and right plug members 21, 21 and the like.

The male screw rotor 1 and the female screw rotor are respectively supported by the bearings at the left and right ends of each shaft in the compressor casing. Further, seals are arranged between the left and right end portions of each shaft and the compressor casing to prevent air leakage.

The input pulley is connected to a crankshaft side pulley via a belt. This crankshaft pulley has a built-in electromagnetic clutch that connects and disconnects the engine and the supercharger. When the electromagnetic clutch is connected, the driving force of the engine is input from the input pulley to the speed increasing gear group to be accelerated, and the screw type air compressor is driven via the timing gear group. At this time,
Due to the synchronizing function of the timing gear set, the screw rotors mesh with each other so as not to contact each other.

The driven air compressor axially pumps the intake air sucked through the suction holes and discharges the intake air through the discharge holes, and the pressurized intake air is supplied to the engine through the intake pipe.

Next, the manufacturing process of the rotor body 3 and the rotor shaft 5 of the screw rotor 1 will be described with reference to FIGS.

For each of these raw materials, a thin pipe having appropriate pressability (ductility) is used.

In the case of the rotor body 3, as shown in FIG. 4, a split mold 23 (female mold) having the surface shape of the rotor body 3 is formed.
Is prepared, a raw material pipe 25 (plate material) is put therein, and pressure is applied from the inside of the pipe 25 with a high-pressure fluid.
The pipe 25 pressurized from the inside expands as shown by the arrow and is pressed by the mold 23, so that the meshing portion 7 and the bottom portion 9 are formed.

At this time, the extension rate of the bottom portion 9 is smaller than that of the meshing portion 7, and the extension rate of the meshing portion 7 increases from the tooth root portion 15 to the tooth tip portion 17, and as described above, the plate thickness is Bottom 9
From the end to the tooth tip 17, the thickness gradually decreases. In addition, as shown in FIG. 2, the bottom portion 9 is formed in a shape circumscribing a cylindrical member such as the rotor shaft 5.

The molded product of the pipe 25 taken out from the mold 23 is cut into a required length as shown in FIG.

In the step of FIG. 4, a long die is prepared to form a long pipe, and in the step of FIG. 5, if this is cut into a plurality of pieces, a large number of intermediate parts 27 can be obtained in one step. It can be molded.

As shown in FIG. 6, the rotor shaft 5 has a large-diameter portion 29 and small-diameter portions 31 and 31 provided on both ends thereof, which are similar to the intermediate part 27 of the rotor body 3. The pipe-shaped raw material placed in the female mold is pressed from the inside to be molded.

As shown by the arrow 33 in FIG. 6, the rotor shaft 5 is fitted on the inner circumference of the intermediate part 27. After that, the side plate members 11 and 13 are press-fitted onto the outer circumferences of the left and right small-diameter portions 31, respectively, as indicated by an arrow 35.

Thereafter, as shown in FIG. 1 and as shown by the arrow 41 in FIG. 7, the bottom portion 9 of the intermediate component 27 and the rotor shaft 5 are spot-welded. Thus, since the rotor shaft 5 is hollow and the electrode of the spot welding machine enters into the rotor shaft 5, spot welding is possible. Then, as shown by the arrow 43 in FIG.
The side plate members 11 and 13 are brazed or welded to 7.

As shown by an arrow 39, the plug members 21 are press-fitted into the left and right openings 37 to be closed.

The spot welding point between the intermediate part 27 and the rotor shaft 5 bears the torque between the rotor shaft 5 and the rotor body 3. On the other hand, at the joint between the intermediate component 27 and the side plate members 11 and 13, since the side plate members 11 and 13 are only press-fitted into the rotor shaft 5, a large torque is not applied. In addition, air leakage between the suction side and the discharge side of the screw type air compressor is prevented from occurring in the side plate member 1.
1, 13 prevent.

Finally, as shown in FIG. 8, the surface of the rotor body 3 is coated to complete the screw rotor 1.

The coating may be performed between the steps of FIG. 4 and FIG.

As described above, the screw rotor 1 has the meshing portion 7 with the female screw rotor and the rotor shaft 5
Unlike the conventional example shown in FIG. 9, the deburring of the plates, the stacking of the plates, the joining of the plates, the surface processing of the rotor body, etc. are not required because the bottom portion 9 for inserting and fixing the The cost is greatly reduced in terms of material cost and processing cost.

The screw rotor 1 is composed of the rotor body 3
Since the rotor shaft 5 and the rotor shaft 5 are both thin plate hollow structures,
It is extremely lightweight and has a very small moment of inertia. Therefore, in a vehicle equipped with an air compressor (supercharger) using the screw rotor 1, the response at the time of acceleration is significantly improved, and the electromagnetic clutch that connects and disconnects with the engine can be downsized.

As described above, since the rotor moment of inertia is small and contact between rotors is prevented even during rapid acceleration / deceleration and contact between rotors due to thermal expansion does not occur, coating of each rotor surface is performed. It can be thinned or even eliminated.

Further, since the bottom portion 9 of the rotor body 3 and the rotor shaft 5 are integrated by spot welding, the joint between them is strong and the joint is low in cost.

Further, the bottom portion 9 of the rotor body 3 is engaged with the engagement portion 7
Since it is formed to be thicker and the strength of the bottom portion 9 is increased, the joint with the rotor shaft 5 is strengthened, and the screw rotor 1
Can bear that much torque.

Further, the rotor body 3 is made of a plate material, but since it has a twisted shape like a helical gear, sufficient rigidity can be obtained.

As described above, according to the rotor forming method of the fifth and sixth aspects, the rotor body and the rotor can be manufactured with extremely high productivity and low cost, and a long pipe is used as a raw material. By cutting the molded product to the required length, it is possible to manufacture a large number of rotor bodies and rotors at a time, which further increases productivity and further reduces cost. In addition, the rotor body 3 or the rotor shaft 5 has an appropriate pressability (ductility), and particularly in the rotor body, the thickness of the bottom portion 9 may be changed by the plastic deformation of the raw material when a high-pressure fluid pressure is applied. It can be easily formed to be thicker.

Although the male screw rotor 1 of the screw type air compressor has been described above as an example, the present invention may be applied to a female screw rotor. Further, the invention can be applied not only to the screw type compressor but also to a rotor of a roots type compressor, for example.

Even if the rotor shaft is solid, the rotor body has a hollow structure, so that the effect of reducing the moment of inertia is great.

Further, various methods other than spot welding can be used for joining the rotor body and the rotor shaft. For example, welding other than spot welding or brazing may be used, or the rotor shaft may be simply press-fitted into the rotor body, and these may be bonded after press-fitting. Such a joining method by press-fitting or gluing is a method that becomes possible only when the inertia moment of the rotor body is sufficiently small, and is particularly useful when the rotor shaft is solid and spot welding cannot be performed.

[0057]

According to the rotors of claims 1 to 4, the meshing portion with the mating rotor and the bottom portion into which the rotor shaft is fitted and fixed are integrally formed of a plate material.

Therefore, unlike the conventional example of FIG. 9, the cost is greatly reduced in terms of material cost and processing cost, and the weight is very small and the moment of inertia is small.

In addition, in a vehicle in which a compressor using this rotor is used as a supercharger, the response at the time of acceleration is greatly improved, and the clutch for connecting / disconnecting with the engine can be downsized. Further, the rotor has a small moment of inertia, prevents contact between rotors even during rapid acceleration / deceleration, and does not cause contact between rotors due to thermal expansion, so the coating on each rotor surface is thinned or eliminated. You can also

According to the rotor of claim 2, in the rotor of claim 1, by making the rotor shaft hollow, the moment of inertia of the rotor is further reduced.

The rotor according to claim 3 utilizes the fact that both the rotor body and the rotor shaft of the rotor according to claim 2 are hollow, and by spot welding these, the rotor body and the rotor shaft can be manufactured at low cost. Can be firmly integrated.

The rotor of claim 4 is the rotor of claim 1, 2 or 3.
In the above rotor, by forming the bottom portion of the rotor main body to be thicker than the other portions, the strength of the bottom portion is increased, the joint portion with the rotor shaft is strengthened, and the rotor can bear such a large torque.

The rotor molding method of claim 5 is a method of molding the rotor of claim 1, 2, 3 or 4 by pressurizing the pipe-shaped raw material arranged inside the female mold from the inside to expand the raw material. It is a highly productive and low cost method. or,
By producing a large number of rotor bodies at once, productivity is further increased and cost is further reduced.

According to a sixth aspect of the present invention, there is provided a rotor molding method in which a pipe-shaped raw material disposed inside a female mold is pressurized and expanded from inside to mold a rotor body and a rotor shaft, respectively.
This is a method of integrating these to form the rotor of claim 1 or 2, and is a method with extremely high productivity and low cost. Further, by producing a large number of rotors at once, the productivity is further increased and the cost is further reduced.

According to the molding method of claims 5 and 6, claim 4
It is possible to easily form the rotor body with a thickness thicker at the bottom than other portions.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along the line BB of FIG.
It is sectional drawing.

FIG. 4 is a cross-sectional view showing a molding process of a rotor body according to the method of the present invention.

FIG. 5 is a front view showing a cutting step of the member formed in the step of FIG.

FIG. 6 is a cross-sectional view showing an assembly process of a rotor molded by the method of the present invention.

FIG. 7 is a sectional view of the rotor assembled in the process of FIG.

FIG. 8 is a front view showing a rotor that is coated after assembly.

FIG. 9 is a partial cross-sectional view of a conventional example.

[Explanation of symbols]

 1 Rotor (Male Screw Rotor) 3 Rotor Main Body 5 Rotor Shaft 7 Interlocking Part 9 Bottom 23 Mold (Female) 25 Pipe (Plate)

Claims (6)

[Claims] 1. A rotor main body having a mating portion with a mating rotor and a bottom portion having a shape of circumscribing a cylinder or a part thereof, and a rotor shaft fitted and fixed to the bottom portion, A rotor in which the meshing portion and the bottom portion are integrally formed of a plate material. 2. The rotor shaft is hollow.
Rotor. 3. The rotor of claim 2, wherein the bottom of the rotor body is spot welded to the rotor shaft. 4. The rotor according to claim 1, 2 or 3, wherein the bottom portion of the rotor body is thicker than the other portions. 5. The method of molding a rotor according to claim 1, 2, 3 or 4, wherein the pipe-shaped raw material arranged inside the female mold is pressurized from the inside to expand to form the rotor body. A method for forming a characteristic rotor. 6. A method of molding a rotor according to claim 1, 2, 3 or 4, wherein a pipe-shaped raw material disposed inside a female mold is pressurized and expanded from the inside to form a rotor body and a rotor shaft, respectively. A method for molding a rotor, which comprises molding the above and integrating them.