JPH09137731A - Screw type supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the machining of a rotor shaft and the installation of the rotor shaft to a rotor in a screw type supercharger in which a pump is acted by the engagement of a pair of screw type female/male rotors, by attaching a flange arranged on the rotor shaft to the end surface of the rotor by a mounting pin. SOLUTION: A male rotor 2 in a pair of screw type female/male rotors, is manufactured by aluminium casting, and a hollow part 19 is formed to a spiral tooth for lightening. That is, at the time of casting, core prints for retaining a core composing the hollow part 19 are arranged on a circumference at approximately equal intervals, and after casting, a hole from which the core prints are eliminated is made to serve as a pin hole 18. A amounting pin 13 is inserted to be extended from a pin hole 17 formed to a flange 12 integrated with a male rotor shaft 9 through the pin hole 18 formed to the male rotor 2 so that the male rotor shaft 9 and the male rotor 2 are connected to each other. Hereby, a shearing quantity to the mounting pin 13 is born on the whole circular arc surface of the mounting pin 13 so as to secure high strength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure for a rotor shaft and a rotor in a screw type supercharger which performs a pumping action by meshing a pair of screw type male and female rotors.

[0002]

2. Description of the Related Art Conventionally, various types of screw type superchargers installed in an intake system of an internal combustion engine have been used. As one of these, the actual Kaihei 3-1 shown in FIG.
The one described in Japanese Patent No. 15219 is exemplified. FIG.
As shown in (A), the screw type supercharger is provided with a female rotor 22 and a male rotor 23, each of which has a plurality of spiral teeth 22A and 23A that are rotationally meshed in opposite directions in a casing. Air supplied from one side in the axial direction is compressed by the compression section formed by the meshing sections of the plurality of spiral teeth, is discharged from the other side in the axial direction, and is used for high-power combustion of the internal combustion engine. It is something. In such a screw type supercharger, in order to perform a reliable pumping action, manufacturing errors are absorbed and the male and female rotors 22, 2
Since it is necessary for 3 to mesh with each other in an accurate phase, a mounting structure for fixing the rotor to the rotor shaft as a separate member is generally adopted so that the rotor can be aligned and aligned with the rotor shaft. There is. Therefore, an aluminum rotor 22 is press-fitted onto an iron shaft 29 as shown in FIG. 5 to integrate the two. However, when the supercharger is activated and the temperature becomes high, the fitting portion becomes loose due to the difference in thermal expansion coefficient between the two and slippage occurs between the male and female rotors, causing a phase shift between the male and female rotors. There was a risk that the rotary mesh would become impossible. Therefore, as shown in FIG. 5, by embedding and driving the pin 33 at the boundary between both fitting portions from one of the shaft centers, even if different materials having different thermal expansion coefficients are fitted, the pin 33 is kept at high temperature. Therefore, the phase between the rotors of male and female should not be disturbed.

[0003]

However, in such a conventional device, as shown in FIG. 5B, generally, the pin 33 is embedded after the rotor shaft 29 and the rotor 22 are fitted and assembled together. It is necessary to form a pin hole 34 for this purpose, and materials having different hardness must be processed at the same time, which is an extremely difficult work. Further, as shown in FIG. 5C, the force in the rotational direction by the rotor shaft 29 for driving the rotor 22 is the same as the rotor shaft 29 and the rotor 2
It acts on the press-fitting force of the fitting portion with 2 and the pin 33 buried in these boundaries, but when the fitting portion loosens due to the difference in thermal expansion coefficient between the two when the supercharger is operating, The pin 33 must bear all the driving force at the outer peripheral portion of the rotor shaft, which is located at a relatively short distance from the shaft center. Moreover, as can be understood from the drawings, this must be borne by almost half of the circumference of the pin 33, and in order to bear a large driving force, the pin 3
The strength of No. 3 tended to be insufficient. Therefore, it is necessary to narrow the press-fitting tolerance between the rotor and the rotor shaft to strengthen the press-fitting force or to increase the strength of the pin, resulting in an increase in processing cost.

Therefore, the present invention solves the various problems in the conventional screw type supercharger, the machining of the rotor shaft is easy, the mounting of the rotor shaft on the rotor is simple and reliable, and (EN) Provided is a screw type supercharger which has a simple structure and low cost, which has a small burden and a large strength.

[0005]

Therefore, according to the present invention, a pair of screw-type male and female rotors fixed to the rotor shafts which are interlocked with each other by meshing timing gears fixed to the pair of parallel rotor shafts. In a screw type supercharger that performs pumping action by meshing with each other, a flange provided on the rotor shaft is attached to an end surface of the rotor by a mounting pin, and this is a means for solving the problem. It is a thing. Further, the present invention is characterized in that a receiving recess for receiving the flange is formed on an end surface of the rotor, and further, the present invention has a projection shape in the axial direction of the flange and the receiving recess for receiving the flange without excess or deficiency. It is characterized by having a circular shape, and these are means for solving the problems.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a partial sectional overall view of a first embodiment of a screw type supercharger of the present invention, and FIG.
FIG. 3 shows an arrow view, and FIG. 3 shows an exploded view of arrow B in FIG. A screw type supercharger installed in an intake system of an engine of an internal combustion engine includes a male and female rotor including helical gears fixed to a pair of male and female rotor shafts 10 and 9 arranged in parallel in a casing 1. The rotor shafts 10, which rotate in conjunction with each other by the engagement of the timing gears 8 and 7,
A plurality of spiral teeth of a pair of screw-type male and female rotors 3 and 2 fixed to 9 (in FIG. 2, three helical teeth 2 of the male rotor 2).
A is drawn. ) To pump. The driving force transmitted from the crankshaft (not shown) to the input pulley 4 through the V belt is transmitted to the input shaft 6 through the connection of the electromagnetic clutch 5, and the shaft end is connected to the input shaft 6 by spline fitting or the like. It is transmitted to the male rotor shaft 9 that has been formed. The on / off of the electromagnetic clutch 5 is computer-controlled by analyzing the throttle opening, the engine speed, the intake air amount, and the like.
On the other hand, a female rotor timing gear 8 is fixed to the shaft end of the female rotor shaft 10 by a tightening nut with a taper ring interposed, and the female rotor timing gear 8 meshes with the male rotor timing gear 7 to screw the male and female screws. The formula rotors 3 and 2 are interlocked and rotated in opposite directions at a predetermined rotation speed ratio. By the rotational engagement of the pair of male and female rotors 3 and 2,
Air supplied from one (right) axial suction port 14 is compressed by the compression chamber 15 formed by the meshing portions of the plurality of spiral teeth and discharged from the other axial discharge port 16. (In the direction perpendicular to the plane of the drawing) for high-power combustion of an internal combustion engine.

In the present invention, as shown by the mounting structure of the male rotor shaft 9 and the male rotor 2 in FIGS. 2 and 3, the flange 12 provided on the male rotor shaft 9 is mounted on the end surface of the male rotor 2. It is configured to be attached by the pin 13,
This structure can also be adopted in the mounting structure of the female rotor shaft 10 and the female rotor 3. The male rotor 2 has, for example, three helical teeth 2A on its outer circumference and is manufactured by aluminum casting or the like. As shown in FIG. 3, those helical teeth 2A generally have hollow portions 19 for weight reduction. Is formed. During casting, a core is interposed to form these hollow portions 19, and a skirting board holding the core is arranged substantially evenly on the circumference. The holes obtained by removing these skirting boards after casting are used as pin holes 18, and the flange 12 provided on the male rotor shaft 9 is used as an insertion hole for the mounting pin 13 attached to the end surface of the male rotor 2. The flange 12 may be provided with a pin hole 17 for mounting the mounting pin 13 in correspondence with the pin hole 18.
A pin may be provided on the flange 12 in advance. If the spiral tooth is not hollow, the core is not necessary and the skirting board hole is not formed. In that case, a hole corresponding to the skirting board hole is machined once as a rotor machining method. The spiral teeth of the rotor are precisely finished based on the wood holes. In the present invention, the flange 12 provided on the male rotor shaft 9 is attached to the end surface of the male rotor 2 by the attaching pin 13. However, as clearly shown in FIG. 3, the end surface of the male rotor 2 is preferably. To the flange 12 of the male rotor shaft 9
Is formed by engraving a receiving concave portion 11 for receiving the flange 12.

With such a structure, the input pulley 4 is rotationally driven by a belt or the like stretched between a crank pulley of an engine (not shown) and the electromagnetic clutch 5 is connected. The rotational driving force from the male rotor timing gear 7 is transmitted to the male rotor shaft 9 and the male rotor timing gear 7 press-fitted to the male rotor shaft 9 via the spline portion, and the driving force from the male rotor timing gear 7 is transmitted to the female rotor timing gear 8 Is transmitted to the female rotor shaft 19 via the to rotate the female rotor 3. Thus, the screw-type male and female rotors 3 and 2 that are interlocked with each other at a predetermined rotation speed ratio and mesh with each other to form the compression chamber 15 are configured to allow the air flowing from the air cleaner (not shown) to the intake port 14 Compressive pressure operation is performed while flowing down in the direction, and then
It is discharged from the discharge port 16 to the outside of the supercharger at high pressure and is used for high-power combustion of the internal combustion engine.

At this time, the driving force from the male rotor shaft 9 is transmitted to the male rotor 2 through the mounting pin 13 provided on the flange 12 provided on the male rotor shaft 9.
The mounting pin 13 located on the circumference relatively far from the shaft center can transmit a large driving force, and at the same time, the mounting pin 13 between the male rotor 2 and the male rotor shaft 9 that acts during driving.
Since the shearing force to the bearing can be borne by the entire arcuate surface of the mounting pin 13, high strength can be secured. Moreover, it is possible to assemble the rotor and the rotor shaft with high accuracy and certainty using the skirting board holes used during casting, and since it is not necessary to press fit the rotor and the rotor shaft, it is possible to fit them within a general tolerance. Done,
Processing cost is low. Further, since materials having different hardness are not machined at the same time, and the rotor shaft provided with the flange is simply provided with the pin holes, the machining is easy and the cost is further reduced. Further, the receiving recess 1 for receiving the flange 12 of the male rotor shaft 9 on the end surface of the male rotor 2.
If 1 is engraved and the flange 12 is housed in the receiving recess 11, the flange 12 does not project, the effective space increases, and the degree of freedom in design increases, and in addition, By performing knurling or the like between the outer periphery and the inner periphery of the receiving recess 11, it becomes possible to pass the load of the driving force acting on the mounting pin 13 to the knurled portion.

FIG. 4 shows a second embodiment of the screw type supercharger of the present invention. FIG. 4 (A) is a first modification and FIG. 4 (B) is a second modification. It is shown. In FIG. 4A, the flange 12 of the male rotor shaft 9 in the first embodiment and the receiving recess 11 that receives the flange 12 without excess or deficiency are used as these flanges 12.
Also, the projection shape of the receiving recess 11 in the axial direction is non-circular, particularly oval. As a result, most of the driving force from the male rotor shaft 9 is carved on the end surface of the male rotor 2 that receives the flange 12 from the elliptical flange 12 provided on the male rotor shaft 9 without excess or deficiency. Since it is directly transmitted to the receiving recess 11 of the shape, it hardly acts on the pin hole 17 formed in the flange 12 and the mounting pin inserted in the pin hole 18 which is the skirting hole of the rotor 2, The strength of the mounting pin is unnecessary.

FIG. 4B shows a second modified example, and the flange 12 of the male rotor shaft 9 and the receiving recess 11 for receiving the flange 12 without excess or deficiency are the flange 12 and the receiving recess 11. It is characterized in that the projected shape in the axial direction of is a non-circle, particularly a polygon, for example, a hexagon. As a result, most of the driving force from the male rotor shaft 9 receives the flange 12 from the hexagonal flange 12 provided on the male rotor shaft 9 in the same manner as in the first modification. It is directly transmitted to the hexagonal receiving recess 11 formed in the end surface of the male rotor 2, and is inserted into the pin hole 17 formed in the flange 12 and the pin hole 18 which is the skirting board hole of the rotor 2. Since it hardly affects the mounting pin, the strength of the mounting pin becomes unnecessary.

The embodiments of the present invention have been described above, but within the scope of the present invention, the material and cross-sectional shape of the screw type male and female rotors, the spiral angle of the rotor teeth, the cross-sectional shape and number, the skirting holes and Position and number of pin holes, shape of flange and receiving recess, shape of suction port and discharge port,
The form of the electromagnetic clutch, the form of the input shaft and the male rotor timing gear, the connecting form of those splines, the press-fitting form of the male rotor timing gear and the male rotor shaft, the press-fitting form of the female rotor timing gear and the rotor shaft, and further It is needless to say that the input pulley, the electromagnetic clutch, the input shaft, and the form of shaft support for the casing of the male rotor timing gear can be appropriately adopted.
It goes without saying that a form in which the input shaft is connected to the female rotor side can be adopted.

[0013]

As described above in detail, according to the present invention, the driving force from the rotor shaft is transmitted to the rotor through the mounting pin provided on the flange provided on the rotor shaft. The mounting pin located on the circumference relatively far from the axis can transmit a large driving force, and the shearing force acting on the mounting pin between the rotor and the rotor shaft to the mounting pin is mounted. High strength can be secured because the entire arc surface of the pin can bear the load. Moreover, it is possible to assemble the rotor and the rotor shaft with high accuracy and certainty using the skirting board holes used during casting, and since it is not necessary to press fit the rotor and the rotor shaft, it is possible to fit them within a general tolerance. The processing cost is low. Further, since materials having different hardness are not machined at the same time, and the rotor shaft provided with the flange is simply provided with the pin holes, the machining is easy and the cost is further reduced. Further, if a receiving recess for receiving the flange of the rotor shaft is formed on the end surface of the rotor and the flange is housed in the receiving recess, the flange is not projected and the effective space is increased to design. In addition to increasing the degree of freedom of, the knurling or the like is performed between the outer periphery of the flange and the inner periphery of the receiving recess to pass the load of the driving force acting on the mounting pin to the knurled portion. Will also be possible.

If the projections of the flange of the rotor shaft and the receiving recesses for receiving the flanges in just proportion are not elliptical or polygonal noncircular, the rotor shaft is driven. Most of the force will be transferred directly from the non-circular flange provided on the rotor shaft to the non-circular receiving recess carved in the end surface of the rotor that receives the flange in proper quantity, and the force will be transmitted to the flange. It hardly acts on the mounting pin inserted in the pin hole provided and the pin hole which is the skirting board hole of the rotor,
The strength of the mounting pin is unnecessary.

[Brief description of the drawings]

FIG. 1 is an overall partial cross-sectional view of a first embodiment of a screw type supercharger of the present invention.

FIG. 2 is a diagram showing a view on arrow A in FIG.

FIG. 3 is a diagram showing an exploded view taken along the arrow B of FIG.

FIG. 4 is an exploded perspective view of a second embodiment of the screw type supercharger of the present invention.

FIG. 5 is a view showing a conventional screw type supercharger.

[Explanation of symbols]

 1 Casing 2 Male rotor 3 Female rotor 4 Input pulley 5 Electromagnetic clutch 6 Input shaft 7 Male rotor timing gear 8 Female rotor timing gear 9 Male rotor shaft 10 Female rotor shaft 11 Receiving recess 12 Flange 13 Mounting pin

Claims (3)

[Claims] 1. A screw type screw mechanism for performing pumping action by meshing a pair of screw type male and female rotors fixed to each rotor shaft, which are interlockingly rotated by meshing timing gears fixed respectively to a pair of parallel rotor shafts. In the feeder, a screw type supercharger in which a flange provided on the rotor shaft is attached to an end surface of the rotor by a mounting pin. 2. The screw type supercharger according to claim 1, wherein a receiving recess for receiving the flange is formed on an end surface of the rotor. 3. The screw type supercharger according to claim 2, wherein the projection shape of the flange and the receiving recess that receives the flange in proper quantity is non-circular.