JP2002213250A - Mechanical supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical supercharger capable of preventing a transmission drive force from lowering, lowering a cost without requiring a high accuracy, and providing an excellent assemblage by effectively allowing a run- out accelerated by a torque variation. SOLUTION: In this mechanical supercharger 1, fluid is pressurized by a pair of rotors 7 and 8 meshed with each other and rotated by receiving a rotating drive force provided from a pulley shaft 4, the rotor shaft 5 of the rotor 7 and the pulley shaft 4 are connected to each other by the fitting through shaft holes 11 and 12 of non-circular shape in cross section and formed with generally spherical surface. Thus, the cost can be reduced without requiring a high cost, an assemblage can be improved, and the shaft can be effectively prevented from being damaged by effectively allowing the run-out accelerated by the torque variation without lowering the transmission drive force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical supercharger in which fluid is pressurized by a pair of rotors meshing and rotating with each other by receiving a rotational driving force obtained by a pulley shaft. The type of the pressurizing section in the supercharger can be applied to a roots type, a Rischhol type, a centrifugal pump type, an axial flow compression type, and the like.

[0002]

2. Description of the Related Art As a mechanical supercharger of this type, which is configured to pressurize fluid by a pair of rotors meshing and rotating with each other by receiving a rotational driving force obtained by a pulley shaft, a special type shown in FIG. Japanese Unexamined Patent Publication No. 1-137338 (Patent No. 27729)
No. 76). This is a supercharger-type mechanical supercharger that is constantly driven by the rotational driving force of the engine. The supercharger 21, which is a supercharger, transmits a driving force from a pulley shaft 24 having an end to which a pulley 23 for obtaining a driving force from the engine is fixed to a first rotor shaft 25, and at the same time, the first rotor shaft 25 The power is transmitted in synchronization with the second rotor shaft 26 via the second timing gear 30 meshing with the first timing gear 29 fixed to the second rotor. The first and second rotors 27, 2 attached to the first and second rotor shafts and engaged with each other, respectively.
The pressurizing action of 8 pressurizes the fluid.

Thus, the outside air introduced from an air cleaner (not shown) is pressurized by the supercharger 21 and supplied to the engine to be subjected to high-output combustion. Since the supercharger 21 is constantly driven to rotate by the driving force of the engine crankshaft, when the engine suddenly shifts to a high output (the same applies at the time of sudden deceleration), the pressure fluctuation accompanying the rapid change of the intake flow rate of the air-fuel mixture. This causes torsional vibrations, backlash and wear in the drive section, the promotion of center runout, gear rattle, and noise due to the generation of air noise.

[0004] In order to prevent such fluctuations in the torque of the driving force in the supercharger and a sudden change in the suction flow rate of the air-fuel mixture caused by the fluctuations in the supercharger, FIG.
In this embodiment, an elastic means is provided between a first pulley shaft 25 and a pulley shaft 24 having a pulley 23 for obtaining a driving force from an engine fixed to an end. The elastic means is constituted by an annular member 31 interposed between an end member 24A fixed to the end of the pulley shaft 24 and the first timing gear 29, and a pin 32 connecting these members. The annular member 31 is disposed within a long hole of the annular member 31 by a torsion spring so as to be movable and restorable within a predetermined range. With such a configuration, torque fluctuation and center runout between the pulley shaft 24 and the first rotor shaft 25 can be effectively absorbed by the elastic means.

[0005]

However, the torque fluctuation is absorbed by the elastic means provided between the pulley shaft 24 and the first rotor shaft 25, and the torsional vibration, backlash and wear of the drive unit are reduced. Although the generation, the runout of the core, the rattling noise of the gear, and the noise due to the generation of the air noise are effectively suppressed, the elastic means is inserted into the long hole via the annular member 31. In addition to the connection structure of the pin 32 and the torsion spring, the structure becomes complicated, resulting in high cost. In addition, the movement of the pin in the long hole and the accumulation of wear when each part is worn due to long-term use. However, there is still a risk that play may occur due to an increase in the length, and in particular, it is difficult to say that the tolerance is low and sufficient as a measure against runout.

Accordingly, the present invention solves the above-mentioned problems in the conventional mechanical supercharger, and effectively allows the runout caused by torque fluctuations and the like, thereby achieving high precision without lowering the transmission driving force. It is an object of the present invention to provide a mechanical supercharger that is inexpensive and easy to assemble.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a mechanical supercharger wherein a fluid is pressurized by a pair of rotors meshing and rotating with each other by receiving a rotational driving force obtained by a pulley shaft. Wherein the rotor shaft and the pulley shaft are connected by a shaft hole fitting with a substantially spherical surface in a non-circular cross section. Further, the invention is characterized in that the non-circular cross section is a polygon. Further, the invention is characterized in that the non-circular cross section is formed by spline fitting. Further, the invention is characterized in that the rotor is screwed to a rotor shaft. Further, the present invention is characterized in that an elastic member is interposed in the shaft hole fitting portion. Further, the present invention is characterized in that the number of teeth of the polygon or the spline is an integral multiple of the number of rotor teeth, and these are used as means for solving the problem.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a mechanical supercharger according to the present invention will be described below with reference to the drawings. FIG. 1 is an overall sectional view showing one embodiment of the mechanical supercharger of the present invention. The present invention relates to a mechanical supercharger 1 configured to pressurize a fluid by a pair of rotors 7 and 8 meshing and rotating with each other by receiving a rotational driving force obtained by a pulley shaft 4. And the pulley shaft 4 are connected by shaft hole fittings 11 and 12 each having a non-circular cross section and a substantially spherical surface. More specifically, the mechanical supercharger 1, which is a supercharger,
A pair of rotors 7 and 8 which are rotatably supported in such a manner that the outer circumference slides on the inner wall in the casing 2 and mesh with each other to form a pressurizing portion.
By rotating meshing, air introduced from a suction port (not shown, for example, on the near side in the drawing) is discharged from a discharge port (for example, in the upper part of the drawing) and pressurized.

The casing 2 is divided into three parts in the axial direction, and from the left side, a pressure casing 2A in which first and second rotors 7, 8 are accommodated, a bearing casing 2B, first and second timing gears 9, 10 The input casing 2 </ b> C in which the pulley shaft 4 is accommodated is arranged and integrated with a fixing bolt. First and second rotor shafts 5, 6 in which the first and second rotors 7, 8 are respectively screwed and fixed.
Is axially supported by the side surface of the pressure casing 2A, and the other end is axially supported by the bearing casing 2B. The first rotor shaft 5 and the second rotor shaft 6 are fixed to first and second timing gears 9, 10 respectively.
Rotate synchronously through the meshing of. The first rotor shaft 5 and the pulley shaft 4 arranged on the same shaft are connected by shaft hole fittings 11 and 12 each having a non-circular cross section and a substantially spherical surface. That is, in the illustrated example, a hole 12 having a hexagonal cross section, for example, is formed as a non-circular detent hole on the end face of the first rotor shaft 5,
Basically, a non-circular cross-section shaft portion 11 having a hexagonal cross-section that matches the hexagonal cross-section is protruded from the end face of the pulley shaft 4, and these are fitted so as to be relatively non-rotatable.

In the present invention, the non-circular cross-section shaft portion 11 having a hexagonal cross section of the pulley shaft 4 has a substantially spherical shape in a side view. Therefore, although the rotor shaft 5 and the pulley shaft 4 are connected to each other by the shaft hole fitting with the non-circular cross section, a relatively large center run-out is allowed at the connection between the rotor shaft 5 and the pulley shaft 4. As the form of the non-circular shaft hole fitting, an appropriate shape such as a polygon such as a triangle, a square, and a hexagon, a spline fitting, and an elliptical shape if relative rotation is impossible, can be adopted. In particular, in the case of non-circular shaft hole fitting by spline fitting, the surface pressure of the fitting part is reduced,
It is possible to transmit a large and reliable driving force. Further, the non-circular cross-section shaft portion 11 of the pulley shaft 4 that allows the center run-out
As the substantially spherical surface in the side view, an arc surface or the like may be employed in addition to the true spherical surface. Further, the shaft may be provided on the rotor shaft 5 and the hole may be provided on the pulley shaft 4. When a non-circular hole 12 is formed in the end face of the rotor shaft 5, when the rotor 7 is screwed into the rotor shaft 5 by the screwing portion 14, the non-circular hole 1 is formed.
2 can be easily assembled by inserting the tool corresponding to 2 and rotating the rotor shaft 7 with respect to the rotor 7.

An elastic member 13 such as an O-ring is provided between the hole 12 of the rotor shaft 5 and the shaft 11 of the pulley shaft 4. In the illustrated example, an O-ring is press-fitted into the shaft portion 11 of the pulley shaft 4 to prevent backlash of the shaft hole fitting portion having a substantially spherical shape in a side view at the time of center run-out behavior. On the other hand, since the torque fluctuation and the pulsation in the rotational direction, which are far causes of the core runout, have a deep relationship with the number of teeth of the rotors 7 and 8 which mesh with each other, the number of polygons in the shaft hole fitting portions 11 and 12 is determined. And the number of teeth of the spline fitting is preferably an integral multiple of the number of teeth of the rotors 7 and 8. As a result, the fitting can be re-fitted to the combination of the relative angles of the shaft portion 11 and the hole portion 12 in the shaft hole fitting portion that can reduce the pulsation generated by the engagement of the rotor.

The embodiments of the present invention have been described above. However, within the scope of the present invention, the type of a mechanical supercharger, for example, a pressurized compression rotor such as a supercharger of the embodiment is used. The present invention is applicable to a centrifugal pump, an axial flow pump, a blower-type vane pump, a gear pump, and the like, in addition to a reciprocal or roots pump by meshing. In addition, the shape of the casing, the shape of the rotor, the shape of the rotor shaft bearing, the shape of the pulley shaft, the shape of the timing gear, the type (meshing with a helical gear to improve quietness), and the non-circular cross-sectional shape of the shaft hole fitting And a substantially spherical shape, a shape, a type and a material of an elastic member, and an arrangement position and an arrangement form,
The form of screwing of the rotor shaft to the rotor and the like can be appropriately selected.

[0013]

As described above in detail, according to the present invention, a mechanical supercharger configured to pressurize a fluid by a pair of rotors meshing and rotating with each other by receiving a rotational driving force obtained by a pulley shaft. By connecting the rotor shaft and the pulley shaft of the rotor with a non-circular cross-section by fitting a shaft hole with a substantially spherical surface, it is inexpensive without high precision, has good assemblability, and has good torque fluctuation. In this way, it is possible to effectively prevent the runout of the core and to effectively prevent the shaft from being damaged, but there is no reduction in the transmission driving force.

Further, according to the present invention, when the non-circular cross section is a polygon, the presence of the corners enables reliable transmission of the driving force. Further, when the non-circular cross section is formed by spline fitting, it is possible to reduce the surface pressure of the shaft hole fitting portion and transmit a large and reliable driving force. Furthermore, when the rotor is screwed to the rotor shaft, when the rotor is screwed to the rotor shaft by a screwing portion, a tool corresponding to the non-circular hole is inserted, and the rotor shaft is inserted into the rotor. It can be easily rotated and assembled.

[0015] When an elastic member is interposed in the shaft hole fitting portion, the backlash of the shaft hole fitting portion at the time of the center runout behavior is prevented. Further, when the number of teeth of the polygon or the spline is an integral multiple of the number of rotor teeth, the relative angle between the shaft portion and the hole portion in the shaft hole fitting portion can reduce the pulsation generated by the meshing of the rotor. Can be re-engaged. Thus, there is provided a mechanical supercharger that effectively allows the run-out caused by torque fluctuation and the like, does not reduce the transmission driving force, does not require high precision, is inexpensive, and has good assemblability. You.

[Brief description of the drawings]

FIG. 1 is an overall sectional view showing a first embodiment of a mechanical supercharger according to the present invention.

FIG. 2 is a sectional view of a main part of a conventional turbocharger.

[Explanation of symbols]

 Reference Signs List 1 supercharger 2 casing 2A pressure casing 2B bearing casing 2C input casing 3 input pulley 4 pulley shaft 5 first rotor shaft 6 second rotor shaft 7 first rotor 8 second rotor 9 first timing gear 10 second timing gear DESCRIPTION OF SYMBOLS 11 Non-circular cross-section shaft part 12 Non-circular cross-section hole part 13 O-ring (elastic member) 14 Threaded part 15 Threaded part

Claims (6)

[Claims] In a mechanical supercharger configured to pressurize fluid by a pair of rotors meshing and rotating with each other by receiving a rotational driving force obtained by a pulley shaft, the rotor shaft of the rotor and the pulley shaft are separated from each other. A mechanical supercharger having a circular cross section and connected by fitting a shaft hole with a substantially spherical surface. 2. The mechanical supercharger according to claim 1, wherein said non-circular cross section is polygonal. 3. The mechanical supercharger according to claim 1, wherein the non-circular cross section is formed by spline fitting. 4. The mechanical supercharger according to claim 1, wherein said rotor is screwed to a rotor shaft. 5. The mechanical supercharger according to claim 1, wherein an elastic member is interposed in the shaft hole fitting portion. 6. The mechanical supercharger according to claim 2, wherein the number of teeth of the polygon or the spline is an integral multiple of the number of teeth of the rotor.