JP2001132461A - Supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a supercharger which can maintain a little clearance around a rotor and avoid the damage by an interference. SOLUTION: This supercharger has a pair of rotors 3, 5 stored in a housing 11 and meshed mutually, rotary shafts 7, 9 integrated with respective rotors 3, 5 and supported by the housing 11 at both ends through bearings 25, 27 and 31, 33 and timing gears 57, 59 fixed on the one end side of respective rotary shafts 7, 9 meshed mutually and rotating both rotors 3, 5 synchronously. The taper part 9c of the rotary shaft 9 is fitted with a timing gear 59 mutually and a coned disk spring 73 is arranged between the inner race 33a of the bearing 33 and the timing gear 59 and positioned in a radial direction and axial direction and fixed by a nut 75.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical supercharger for supercharging intake air of an engine, and more particularly to a method for fixing a timing gear.

[0002]

2. Description of the Related Art As a conventional supercharger, for example, Japanese Unexamined Patent Publication No.
Japanese Patent Laid-Open Publication No. 0-11694 discloses the one shown in FIG. This is a roots type supercharger 201.

[0003] A pair of rotors 203 and 205 made of a light-weight material such as aluminum are shown in a partially cut-away manner.
It is fixed on steel shafts 207, 209 arranged in parallel. Both rotors 203 and 205 are provided with respective shafts 20.
7, 209 are supported on the wall of the housing 221 via bearings 211, 213 and 215, 217, and housed in the housing chamber 221a of the housing 221.

The shafts 207, 20 of the rotors 203, 205
9 penetrates the wall of the accommodation room 221a and
23. The shaft 207 of the driving rotor 203
Further extend through the wall of the left cover 225 to the outside.

The shaft 207 has a bearing 227
Through the cover 225. A V-groove-shaped pulley, for example, is attached to the tip 207d of the shaft 207 extending to the outside, and the belt is driven by the engine.

In the gear chamber 223, timing gears 231 and 233 are fixed on the respective shafts 207 and 209. Due to the engagement of the timing gears 231 and 233, the two rotors 203 and 205 are moved between the tooth surfaces of each other and the housing chamber 221a.
With a slight clearance between them.

In this way, the internal leakage of the fluid is suppressed while the contact is prevented by the slight clearance, and the charging efficiency of the intake air of the engine is increased. The thermal expansion accompanying the temperature rise during operation is caused by the difference in the material between the rotors 203 and 205 in the shafts 207 and 2.
09, the rotors 203 and 205 and the shaft 20
If the backlash is formed between the first and the seventh and the second and the second 209, a fatal damage such as burn-in may be caused.

Therefore, each of the rotors 203 and 205 and the shaft 20
7 and 209, the rotors 203 and 2
The hole diameter of 05 is the large diameter portion 203a, 205 at the mouth (left end).
a and the smaller diameter portions 203b and 205b on the far side (right end side).
It is processed into a step, and the large diameter portion 207a, 2
09a and the small-diameter portions 207b and 209b on the distal end side are respectively press-fitted, and then the large-diameter portions of the shaft are subjected to parallel knurling to enlarge the knurl portions 207c and 209c while shaving the large-diameter portions 203a and 205a of the holes. It is press-fitted.

Thus, the knurl portions 207c, 209
c to provide a structure that further covers the difference in thermal expansion, and the shafts 207 and 209 and the rotors 203 and 205 during operation.
I try to keep the integration with.

The shaft 209 on the driven side and the timing gear 233 are fitted together with the stepped straight shaft portion 20 on the shaft 209 side.
9d and 209e are press-fitted into corresponding straight holes on the timing gear side, respectively.
9f is press-fitted similarly to the rotors 203 and 205 described above. In this case, the inner periphery of the timing gear 233 is
It is softer than the 9 side.

[0011]

However, when the timing gear 233 is press-fitted into the shaft 209, the timing gear 233 falls down and is press-fitted. At that time, the press-fitting portion has a large interference, so that galling occurs at the press-fitting portion. There is. As a result, whirling of the timing gear 233 occurs and backlash increases, noise increases, and whirling of the driven-side rotor 205 is induced to cause the rotors 203 and 2 to rotate.
The rotors 203 and 205 may interfere with each other because the synchronous rotation of the rotor 05 is shifted.

Since the timing gear 231 is attached to the drive shaft 207 by using the fitting of the tapered portions of the two members 207 and 231, there is no danger of galling at the time of attachment. Axis 207
It does not have a function of preventing whirling of the (rotor 203) or preventing movement in the axial direction.

Accordingly, an object of the present invention is to provide a supercharger capable of maintaining a small clearance around the rotor and avoiding damage due to interference.

[0014]

According to a first aspect of the present invention, there is provided a pair of rotors housed in a housing and meshing with each other, and a pair of rotors integrated with each of the rotors and bearings at both ends. And a timing gear fixed to one end of each of the rotating shafts and meshing with each other to synchronously rotate both rotors, wherein the rotating shaft and the timing gear And the timing gear is axially positioned between the timing gear and the housing via an elastic member and fixed by a fixing tool.

Therefore, unlike the above-described conventional example in which the timing gear is centered on the rotary shaft by press fitting of the timing gear, the centering of the timing gear can be performed without difficulty by fitting the tapered portion, so that the fixing portion can be prevented from galling. Since the rotating shaft is urged toward the timing gear side and fixed to the housing by the elastic member, the backlash of the bearing is eliminated, and the centering of the rotating shaft and the timing gear with respect to the housing and the positioning in the axial direction are reliably performed. . Thereby, whirling and displacement of the rotor are reliably suppressed, and interference and the like can be avoided.

According to a second aspect of the present invention, in the supercharger according to the first aspect, the elastic member is a disc spring, and is disposed between an inner race of the bearing and a timing gear. It is characterized by the following.

Therefore, the same operation and effect as those of the first aspect of the invention can be obtained, a compact structure can be realized by the disc spring, and one side of the disc spring contacts the timing gear and the other side contacts the timing gear. An easy-to-assemble configuration in which the rotating shaft and the timing gear can be positioned with respect to the housing by abutting against the inner race of the bearing and then via the ball and the outer race can be achieved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view of the present embodiment. The supercharger 1 is a roots-type blower driven by a belt by a crankshaft of an engine.

As shown in FIG. 1, a pair of rotors 3 and 5 on the driving side and the driven side are rotated at respective rotation centers by rotating shafts 7 and 9.
And is housed in the housing chamber 11a of the housing 11.

The rotors 3 and 5 are formed in the same shape and mesh with each other, and rotate in opposite directions while maintaining a slight clearance between the rotor 3 and the housing 11 and between them. Rotor 3,5
The housing 11 for housing the
A plate 17 positioned by the pin 15;
The cover 19 and the cover 19 are connected by bolts 21.

The rotation shafts 7 and 9 on the driving side and the driven side are integrated with the rotors 3 and 5, respectively.
At both ends (left and right ends in FIG. 1) of the rotary shafts 7 and 9, the rotary shafts 7 and 9 are centered by light press-fitting with two press-fitting portions 7 a and 7 b and 9 a and 9 b, respectively. Screws 3b, 5b in the direction corresponding to the rotation direction of (each rotor 3, 5)
(Right-handed screw if clockwise rotation).
The hole 23 at the right end of the driven side rotation shaft 9 is a hole for a jig at the time of assembly.

Each of the rotating shafts 7 and 9 has a bearing (angular bearing in this embodiment) 2 at each end.
It is supported by the housing 11 via 5, 27 and 31, 33, and is arranged in parallel. As the bearings 25 and 31 on the left end side, double-sided sealed bearings filled with grease are used, and the inner races 25a and 31a are strongly pressed into the rotating shafts 7 and 9, respectively. Each outer race 25
disc spring 3 between the inner end of b and 31b and the housing 11
5 and 37 and washers 41 and 43 are arranged.
The disc springs 35, 37 urge the rotating shafts 7, 9 and the rotors 3, 5 to the left in FIG. 1 via the balls of the bearings 25, 31 and the inner races 25a, 31a.

The bearing 25 at the left end of the drive-side rotary shaft 7
In the portion, the disc spring 35 is arranged to be bent by a predetermined amount by the ring nut 45. Further, a V-pulley 47 is spline-connected to the shaft end of the drive-side rotary shaft 7, and a nut 51
It is fixed by. The driving force from the crankshaft of the engine is input to the driving-side rotary shaft 7 via the V pulley 47. On the other hand, the bearing 31 at the left end of the driven-side rotary shaft 9 is sealed by a plug 53.

A gear chamber 55 is provided surrounded by the plate 17 and the cover 19. Both right end shaft ends of the rotary shafts 7, 9 extend into the gear chamber 55, and are integrated with the timing gears 57, 59 by a configuration described later. The gear chamber 55 is filled with a predetermined amount of oil to lubricate the bearings 27 and 33 and the timing gears 57 and 59 that support the rotating shafts 7 and 9. The oil is supplied to the oil seals 61 and 63 and the O-ring 65 on each of the rotating shafts 7 and 9.
Prevents leakage to the outside.

A drive-side timing gear 57 is fixed on a right end of the drive-side rotary shaft 7 by a nut 71 via a C-shaped taper ring 67. At this time, the drive timing gear 57 is in contact with the inner race of the bearing 27, and the nut 71 is in contact with the tapered ring 67. Thus, the drive-side rotary shaft 7 (rotor 3) and the drive-side timing gear 57 are positioned by being biased leftward with respect to the housing 11 by the disc spring 35 of the left end bearing 25.

On the other hand, the tapered portion 9c at the shaft end of the driven-side rotating shaft 9 has a bearing 3 lightly pressed into the driven-side rotating shaft 9.
The driven-side timing gear 59 is inserted between the inner race 33a and the third inner race 33a via a disc spring 73 (elastic member), and the disc spring 73 is bent by a predetermined amount by a nut 75 and fixed.

Thus, the driven-side timing gear 59 is integrated with the driven-side rotary shaft 9 and urged rightward with respect to the housing 11 by the disc spring 73. At this time, the inner end of the disc spring 73 is connected to the inner race 33a of the bearing 83, the ball and the outer race 33b.
, The bearing 33 is free from radical play and axial play.

In this assembled state, the urging force of the disc spring 73 to the right is set to be greater than the urging force of the disc spring 37 at the left end to the left. Thus, it is positioned with respect to the driven side timing gear 11.

Timing gears 57, 59 for synchronously rotating the rotating shafts 7, 9 are centered on the rotating shafts 7, 9 at the tapered portions, and are rotated by the disc springs 35, 37, 73.
Since the positioning of the timing gears 57 and 59 is prevented in the axial direction and the radical direction together with the housing 9, the timing gears 57 and 59 are prevented from staking and whirling.

Thus, according to the present embodiment, the centering of the timing gear 59 with respect to the driven rotary shaft 9 can be performed without difficulty, unlike the above-described conventional example in which the timing gear is press-fitted. Is prevented, and the rotating shaft 9 is urged and fixed to the housing 11 by the disc spring 73 toward the timing gear 59 side.
And the timing gear 59 is reliably positioned in the radial and axial directions. Thereby, whirling and displacement of the rotor 5 are reliably suppressed, and interference between the rotors 3 and 5 and with the housing 11 can be avoided.

Further, the use of the disc spring allows a compact structure, and also the disc spring 73 as described above.
Is provided so as to contact one side with the timing gear 59 and the other side with the inner race 33a of the bearing 33 so that the rotation shaft and the timing gear 59 are positioned with respect to the housing 11 via the ball and the outer race 33b. Therefore, it is possible to make the structure easy to assemble.

In addition, since the disc spring 73 as the urging means works in the direction of pressing the timing gear 59 against the nut 75 as the fixing member, it also functions as a mechanism for preventing the fixing portion from loosening.

[0033]

As is apparent from the above description, according to the first aspect of the present invention, the centering of the timing gear with respect to the rotating shaft is different from that of the conventional example in which the timing gear is press-fitted, unlike the conventional example. The fitting can be carried out without difficulty, so that the fixing portion is prevented from galling, and the rotating shaft is urged toward the timing gear with respect to the housing and fixed by the elastic member. The centering of the rotating shaft and the timing gear with respect to the shaft and the positioning in the axial direction are reliably performed.
Thus, whirling and displacement of the rotor are reliably suppressed, and fatal damage due to interference can be avoided.

According to the invention described in claim 2, according to claim 1
The same effect as that of the invention can be obtained, and a compact structure can be realized by the disc spring.In addition, one side of the disc spring contacts the timing gear, and the other side contacts the inner race of the bearing, for example. The rotation shaft and the timing gear can be positioned with respect to the housing via the ball and the outer race, and can be easily assembled.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of the present invention.

FIG. 2 is a sectional view of a conventional example.

[Explanation of symbols]

 3,5 Rotor 3b, 5b Screw 7,9 Shaft 7a, 7b, 9a, 9b Press-fit part 9c Taper part 11 Housing 25,27,31,33 Bearing 25a, 31a, 33a Inner race 35,37,73 Disc spring (elasticity) Members) 57, 59 Timing gear 75 Nut (fixture)

Claims (2)

[Claims] 1. A pair of rotors housed in a housing and engaged with each other, a rotating shaft integrated with each of the rotors and supported by the housing at both ends via bearings, and one end of each of the rotating shafts And a timing gear fixedly engaged with each other to synchronously rotate both rotors, wherein the rotating shaft and the timing gear are fitted at respective tapered portions and the timing gear is connected to the housing. A supercharger characterized by being axially positioned via an elastic member therebetween and fixed by a fixture. 2. The supercharger according to claim 1, wherein the elastic member is a disc spring, and is disposed between an inner race of the bearing and a timing gear. Machine.