JPH09189231A - Twin-shaft mechanical supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a twin-shaft mechanical supercharger which dispenses with the taper press fit which requires the small press fit tolerance and high accuracy, is capable of correctly fitting a timing gear to a rotor shaft by sure fixing without loosening while the regular press fit with sure alignment is adopted, and capable of fine adjustment of the phase characterized in the adjustment of the clearance between respective members without disassembling, and is inexpensive. SOLUTION: In a twin-shaft mechanical supercharger in which a pair of rotors 2, 3 are rotated by the engagement of rotor timing gears 7, 8 comprising helical gears press fitted to rotor shafts 2A, 3A in a pair of rotors 2, 3 to be engaged with a clearance therebetween, and the gears are engaged to perform the pumping, at least one rotor timing gear 8 out of the rotor timing gears 7, 8 is press fitted and tightened to the rotor shaft 3A by interposing an elastic body 9 having the restoring force in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a twin-screw mechanical supercharger for supplying a high output by supplying air to an engine or the like by a pair of rotors meshing with each other with a gap maintained therebetween.

[0002]

2. Description of the Related Art Conventionally, a screw type supercharger as an example of a twin-screw mechanical type supercharger installed in an intake system of an engine of an internal combustion engine is described in JP-A-3-279689 shown in FIG. It is illustrated by what was done. The screw type supercharger shown here has a male rotor 22 composed of a plurality of spiral teeth, which are meshed in opposite directions in a casing 21.
And the female rotor 23, the air supplied from one axial direction is compressed by the compression section formed by the meshing portions of the plurality of spiral teeth, and is discharged from the other axial direction to generate internal combustion. It is used for high-power combustion of a formula engine. Such a screw type supercharger is rotationally driven by a driving force transmitted from a crankshaft (not shown) via a V-belt, but usually, an electromagnetic clutch 25 is incorporated to reduce mechanical loss, and a throttle is used. The electromagnetic clutch 25 is disengaged under computer control by analyzing the opening degree, engine speed, intake air amount, and the like.

The rotation of the input shaft 26, which is rotationally driven by obtaining power by connecting the electromagnetic clutch 25, is driven by the drive gear 3.
1, transmitted to the female rotor shaft 22A via the speed increasing gear 32. A screw type female rotor 22 is fixed to the female rotor shaft 22A, and a screw type male rotor 23 is fixed to a male rotor shaft 23A arranged in parallel with the female rotor shaft 22A. On the other hand, the speed increasing gear 32 and the female rotor timing gear 2 are formed on the input shaft side of the female rotor shaft 22A by taper coupling.
7 and 7 are centered by bolts 21 and press-fitted and fixed,
A male rotor timing gear 28 is press-fitted or key-fixed by a bolt 30 at the shaft end of the male rotor shaft 23A. The male and female rotor timing gears 27, 28 mesh with each other while maintaining a gap therebetween to rotate the female and male screw type rotors 22, 23 in opposite directions. Generally, the female and male rotor timing gears 27 and 28 are meshed with each other by helical gears, and the rotational direction and axial position of the female rotor timing gear 27 with respect to the female rotor shaft 22A, that is, the press-fitting amount is selected. The timing gear 27 is configured to be appropriately adjusted with respect to the phase of the spiral teeth of the female rotor 22, and the meshing phase of the female rotor timing gear 27 with the male rotor timing gear 28 can be appropriately adjusted. Then, as mentioned above,
On the input shaft side of the female rotor shaft 22A, the speed increasing gear 32 and the female rotor timing gear 27 are centered by press-fitting and press-fitted and fixed by taper coupling, thereby preventing eccentricity of the timing gear and rotating direction at high speed rotation. It also prevents the displacement of the position.

[0004]

However, in the supercharger including the screw type rotor of such a type, the adjustment of the female rotor timing gear 27 with respect to the phase of the spiral teeth of the female rotor 22 and the female rotor timing gear are performed. Two
In order for the meshing phase of the male rotor timing gear 28 of FIG. 7 to maintain a predetermined gap to be proper, the assembling position and centering of the female rotor timing gear 27 in the female rotor shaft 22A in the axial direction and the rotational direction must be accurate. Must be
The taper joint between the speed increasing gear 32 and the female rotor timing gear 27 requires extremely strict accuracy.
In addition, in order to prevent the displacement of the female rotor timing gear 27 with respect to the female rotor shaft 2A, it is necessary to narrow the press-fitting tolerance at the taper coupling portion and tighten the bolt 21 strongly. For this reason, not only the taper processing cost becomes high and expensive, but also the phase shift occurs between the timing gear and the rotor shaft due to long-term use, and in the worst case, the phase shift of the meshing between the male and female rotors occurs. There is also a possibility that the pump function of the supercharger may be impaired due to the occurrence of the above. Moreover, since the timing gear is properly fixed to the rotor shaft with the tightening bolts or the like, no special mechanism is provided for preventing the tightening bolts or the like from loosening.
If an excessive driving load is applied due to sudden acceleration of the vehicle or if there is a misalignment between the timing gear and the rotor shaft due to long-term use, use a simple method for fine adjustment. Phase matching was impossible, and the device had to be disassembled and reassembled, which was extremely troublesome.

Therefore, the present invention solves various problems in the conventional twin-screw mechanical supercharger, and eliminates the need for taper press-fitting, which has a narrow press-fitting tolerance and requires high precision, and is a normal centering method that ensures centering. While adopting the press-fitting, the timing gear can be accurately attached to the rotor shaft by securely fixing it without loosening, and it is also possible to finely adjust the phase, which is characterized by adjusting the clearance between each member without disassembling. Provide a low-cost two-shaft mechanical supercharger.

[0006]

Therefore, according to the present invention, the pair of rotors is meshed with rotor timing gears, each of which has helical teeth press-fitted into each rotor shaft of a pair of rotors meshing with each other while maintaining a clearance therebetween. In a two-shaft mechanical supercharger that rotates and its teeth are engaged with each other to perform a pumping action, at least one rotor timing gear among the rotor timing gears is provided with an elastic body having a restoring force in the axial direction interposed therebetween. It is characterized in that the rotor shaft is press-fitted and tightened. Further, the present invention is characterized in that a pin for preventing relative rotation between the rotor timing gear and the rotor shaft is attached to a press-fitting portion between the one rotor timing gear and the rotor shaft. It is a means for solution.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an essential part of one embodiment of a screw type supercharger as a two-shaft mechanical type supercharger of the present invention.
In FIG. 1, most of the air intake and discharge parts and the male and female rotors in the screw type supercharger of the present invention are omitted. A screw type supercharger installed in an intake system of an engine of an internal combustion engine includes a screw provided with a plurality of spiral teeth (not shown) that are arranged in parallel in a casing 1 and rotationally mesh with each other in opposite directions. A male rotor 2 and a female rotor 3 are provided. These screw type male and female rotors 2 and 3 are rotationally driven through the connection of the electromagnetic clutch 5 by the driving force transmitted from the crankshaft (not shown) to the input pulley 4 via the V-belt, and one side in the axial direction (the suction on the right side). Part) is compressed by the compression chamber 15 formed by the meshing parts of the plurality of spiral teeth, and is discharged from the other discharge port in the axial direction (in the direction perpendicular to the paper surface). It is used for high-power combustion of a formula engine. The connection and disconnection of the electromagnetic clutch 5 arranged between the input pulley 4 and the input shaft 6 is computer-controlled by analyzing the throttle opening, engine speed, intake air amount and the like.

The screw type male and female rotors 2 and 3 are fixed to the male and female rotor shafts 2A and 3A which are rotatably supported by bearings in the casing 1, and one female rotor shaft 2A is fixed.
The inner circumference of the input shaft 6 which can be freely connected to and disconnected from the input pulley 4 is connected to the outer circumference of the input side shaft end by means of the electromagnetic clutch 5 by spline fitting or the like, and is firmly fixed by tightening bolts 11 or the like. In the present invention, the female rotor shaft 2A connected to the input shaft 6 has the female rotor timing gear 7 formed of a helical tooth, and the boss portion of the female rotor timing gear 7 is press-fitted and fixed by normal press-fitting without a taper. Although the boss portion of the male rotor timing gear 8 which is externally meshed with the timing gear 7 and also has helical teeth is press-fitted and fixed to the male rotor shaft 3A by normal press-fitting without using a taper, particularly in the present embodiment. , The male rotor timing gear 8 to the male rotor shaft 3A
When press-fitting into the, the cross section hat type elasticity having a restoring force in the axial direction between the side surface of the boss portion of the male rotor timing gear 8 and the side surface of the inner race of the bearing 14 that pivotally supports the male rotor shaft 3A on the casing 1. The body 9 is interposed, and the elastic body 9 is pressed against the restoring force and is press-fitted and tightened by a tightening nut 10 screwed to the shaft end of the male rotor shaft 3A. In the present embodiment, a large restoring force in the axial direction is obtained by the elastic body 9 having a hat-shaped cross section.

Although various materials can be adopted for the elastic body 9, the restoring spring force of the elastic body 9 when the tightening nut 10 is loosened is the male rotor shaft 3A of the male rotor timing gear 8.
Is set to be strong enough to overcome the pressure input to the male rotor timing gear 8 and push back the male rotor timing gear 8 in the axial direction, but the relative rotation between the male rotor timing gear 8 and the male rotor shaft 3A in the driving rotation direction. By adopting a press-fitting method in which only rotation can be reliably prevented and axial movement can be securely tightened with a relatively small pressure input, the restoring spring force of the elastic body 9 can be made small. Further, in the present invention, only the male rotor timing gear 8 is tightened with the elastic body 9 interposed between the female and male rotor timing gears 7 and 8 and for setting and adjusting the phases of the rotors 2 and 3. It is needless to say that the invention can be applied not only to the female rotor timing gear 7 side but also to the female rotor timing gear 7 side only. Further, in the present invention, a pin 12 for preventing relative rotation between the male rotor timing gear 8 and the male rotor shaft 3A is provided in a press-fitting portion between the male rotor timing gear 8 and the male rotor shaft 3A.
May be attached. In addition, as the twin-screw mechanical supercharger of the present invention, a pair of male and female rotors 2 and 3 as shown in FIG. In addition to the above, each of the rotor shafts 2A and 3A of the two-shaft mechanical supercharger having a pair of cocoon type rotors 2 and 3 that mesh with each other while maintaining a predetermined gap as shown in FIG. It can be applied to a rotor timing gear mounted on a rotor shaft.

With the above construction, according to the present invention, with respect to the female rotor timing gear 7 similarly fixed to the female rotor shaft 2A to which the screw type female rotor 2 is press-fitted and fixed at a predetermined phase. A male rotor timing gear 8 in which a helical tooth is meshed is easily moved and adjusted in the axial direction by screwing a tightening nut 10 forward and backward with an elastic body 9 having a restoring force in the axial direction interposed. As a result, the meshing phase between the male rotor timing gear 8 and the female rotor timing gear 7 that meshes with the male rotor timing gear 8 by helical teeth, and a predetermined phase with respect to the male rotor shaft 3A. The fine adjustment of the phase of the male rotor timing gear 8 with respect to the male rotor 3 press-fitted and fixed in phase can be easily performed. Regarding the female rotor 2 side, a female rotor timing gear 7 for the female rotor shaft 2A is provided.
Even if the female rotor 2 and the female rotor 2 are initially fixed and set to a predetermined phase, it is possible to adjust the axial position of the male rotor timing gear 8 with respect to the male rotor shaft 3A. The meshing phase between the male and female rotors 2 and 3 is indirectly adjusted through adjustment of the meshing phase with respect to. As described above, according to the present invention, there is no need for a taper press-fitting which has a narrow press-fitting tolerance and requires high precision, and while adopting a normal press-fitting that ensures centering, an elastic force having a restoring force in the axial direction is adopted. By interposing the body 9, the male rotor timing gear 8 can be easily moved in the shaft end direction even when the tightening nut 10 is loosened and retracted, and its adjustment is easy, and the shaft is Since the elastic body 9 having a restoring force in the direction always presses the tightening nut 10 via the male rotor timing gear 8, the tightening nut 10 does not loosen loosely. Moreover, in the unlikely event that the phase between each member deviates,
It is only necessary to adjust the axial position of the male rotor timing gear 8 without disassembling each member on the male and female rotor sides, and it is possible to provide a low-cost screw type supercharger with a simple structure. If a hole for adjusting the tightening nut 10 is formed in the casing 1 at a position corresponding to the tightening nut 10, it is not necessary to disassemble the casing itself. Further, if a pin 12 for preventing relative rotation between the male rotor timing gear 8 and the male rotor shaft 3A is attached to the press-fitting portion between the male rotor timing gear 8 and the male rotor shaft 3A, the presence of the pin 12 is present. By male rotor timing gear 8 and male rotor shaft 3
A means that the restoring force of the elastic body 9 can be set to a small value without rotating indefinitely even if it is not strongly pressed in.

FIG. 2 shows a second embodiment of the screw type supercharger of the present invention, and is an enlarged sectional view of an essential part corresponding to part A of FIG. FIG. 2A shows a first modification of the elastic body.
(B) is a second modification of the elastic body. Explaining in detail below, as shown in FIG. 2A, in the first modification of the elastic body 9 in the second embodiment, when the male rotor timing gear 8 is press-fitted into the male rotor shaft 3A, A pair of disc springs 9A are provided as elastic bodies 9 having a restoring force in the axial direction between the side surface of the boss portion of the male rotor timing gear 8 and the side surface of the inner race of the bearing 14 that pivotally supports the male rotor shaft 3A on the casing 1. , 9B are arranged so as to face each other, and a great restoring force in the axial direction cannot be obtained as compared with the elastic body 9 having the hat-shaped cross section of the first embodiment. When used together, it is possible to adjust the position of the male rotor timing gear 8 in the axial direction by the light tightening nut 10.

As shown in FIG. 2B, in the second modification of the elastic body 9 according to the second embodiment, when the male rotor timing gear 8 is press-fitted into the male rotor shaft 3A,
As an elastic body for returning the male rotor timing gear 8 in the axial direction, an annular groove 13 is formed on both the boss portion of the male rotor timing gear 8 and the male rotor shaft 3A,
The coil spring 9C is housed in the groove 13. The coil spring 9C contacts the male rotor shaft 3A side of the groove 13 on the inner diameter side and the male rotor timing gear 8 of the groove 13 on the outer diameter side.
The male rotor timing gear 8 is urged toward the shaft end side by its restoring force. This modification can be applied to the case where a restoring force smaller than that of the disc springs 9A and 9B of the first modification is sufficient, and since the coil spring 9C is housed in the boss of the male rotor timing gear 8, the lubricating oil Since it is isolated from wear dust and the like accumulated inside, the smooth action of the coil spring 9C can be brought out when adjusting the axial position of the male rotor timing gear 8 by the tightening nut 10 after long-term use. Always possible.

Although the embodiments of the present invention have been described above, the material, the cross-sectional shape, the spiral angle of the rotor teeth, the cross-sectional shape and the number of the rotor teeth, such as the screw type and the roots type rotor, are within the scope of the gist of the present invention. Shape of ports and discharge ports, form of electromagnetic clutch, form of input shaft and rotor timing gear, connection form of splines, etc., press fit form of rotor timing gear and rotor shaft, and further input pulley, electromagnetic clutch, input It is needless to say that the shaft and rotor timing gears to be supported on the casing, the sectional shape of the elastic body, the material, the installation form, the pin shape, the installation form, the tightening nut screwing form, and the like can be appropriately adopted. That's a good thing. Further, it goes without saying that a form in which the input shaft is connected to the male rotor side can be adopted.

[0014]

As described in detail above, according to the present invention, a helical gear meshes with the other rotor timing gear that is similarly fixed to the rotor shaft in which the rotor is press-fitted and fixed in a predetermined phase. At least one of the rotor timing gears can be easily moved and adjusted in the axial direction by screwing the tightening nut forward and backward with an elastic body having a restoring force in the axial direction interposed therebetween. Fine adjustment of the meshing phase between the other rotor timing gear that meshes with the helical gear and one rotor timing gear, and the phase of one rotor timing gear with respect to the rotor that is press-fitted and fixed to the rotor shaft at a predetermined phase Can be done easily. As described above, with respect to the other rotor side, even if the rotor timing gear and the rotor for the rotor shaft are fixed and set to the initial predetermined phase, the rotor timing gear of the one rotor timing gear does not move in the axial direction with respect to the rotor shaft. By adjusting the position, the meshing phase between the rotors can be indirectly adjusted by adjusting the meshing phase with respect to the other rotor timing gear.

Thus, according to the present invention, there is no need for a taper press-fitting which has a narrow press-fitting tolerance and requires high precision, and while adopting a normal press-fitting that ensures centering, it has a restoring force in the axial direction. By interposing an elastic body, the rotor timing gear can easily move in the axial end direction even if the tightening nut is loosened and retracted, and its adjustment is easy and restores in the axial direction. Since the elastic body having a force constantly presses the tightening nut via the rotor timing gear, the tightening nut does not loosen loosely. Moreover, even if the phases of the respective members deviate from each other, it is sufficient to simply adjust the axial position of the rotor timing gear without disassembling the respective members on the rotor side. A shaft mechanical supercharger can be provided.

If a pin for preventing relative rotation between the rotor timing gear and the rotor shaft is attached to the press-fitting portion between the one rotor timing gear and the rotor shaft, the presence of the pin causes the rotor timing gear to be connected to the rotor timing gear. The rotor shaft does not rotate inadvertently regardless of strong press-fitting, and the restoring force of the elastic body can be set to a small value. Further, in the present invention, it is not necessary to form the tapered portion and narrow the press-fitting tolerance in the tapered portion to strongly tighten the tightening nut to prevent the rotor timing gear from being displaced with respect to the rotor shaft, unlike the conventional one. Therefore, it is possible to adopt a simple press-fitting structure with a small press-fitting tolerance and a small press-fitting allowance, which does not require strict precision, and the working cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is an overall cross-sectional view showing a first embodiment of a twin-screw mechanical supercharger of the present invention, in which a screw type supercharger is partially omitted.

FIG. 2 is a cross-sectional view of essential parts of a second modification of the elastic body, showing the second embodiment of the biaxial mechanical supercharger of the present invention.

FIG. 3 is a diagram showing a main part of a screw type supercharger and a roots type supercharger which are adopted as the twin-screw mechanical type supercharger of the present invention.

FIG. 4 is an overall cross-sectional view, partly omitted, showing a conventional screw type supercharger.

[Explanation of symbols]

 1 casing 2 rotor (female) 2A rotor shaft (female) 3 rotor (male) 3A rotor shaft (male) 4 input pulley 5 electromagnetic clutch 6 input shaft 7 rotor timing gear (female) 8 rotor timing gear (male) 9 elastic body 10 tightening nut 11 tightening bolt 12 pin 13 groove 14 bearing 15 compression chamber

Claims (2)

[Claims] 1. A pair of rotors in a pair of rotors meshing with each other with a gap held therebetween are meshed with rotor timing gears each of which has a helical tooth press-fitted into each rotor shaft. In a two-shaft mechanical supercharger that operates as a pump, at least one rotor timing gear of the rotor timing gears is press-fitted and tightened onto the rotor shaft with an elastic body having an axial restoring force interposed. A two-axis mechanical supercharger. 2. The pin for preventing relative rotation between the rotor timing gear and the rotor shaft is attached to a press-fitting portion between the one rotor timing gear and the rotor shaft. Biaxial mechanical supercharger.