JP3084007B2 - Shaft drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft driving device used for transmitting a rotational driving force (hereinafter, also referred to as a rotational force) to a camshaft or a rear wheel in an engine of a motorcycle or a four-wheeled vehicle. About.

[0002]

2. Description of the Related Art A shaft drive of this type does not need to be adjusted for elongation like a chain or a belt, and is free from oil contamination, as compared with a torque transmission device using a chain or a belt.
In recent years, because of its high drive efficiency, long-term stable transmission of torque, long durability, and low transmission noise, it has recently been used to transmit engine rotational drive to the rear wheels and camshaft. Being used to do so. By the way, in a shaft drive device, since rotational force is normally transmitted through bevel gears meshing with each other, if the clearance of the meshing portion (between teeth) of the bevel gears is inappropriate, noise (tooth contact noise) is generated. It is necessary to adjust the clearance because there is a risk of emission or wear in a short time. As shown in an exploded perspective view of FIG. 6, a conventional shaft driving device includes bevel gears 50 and 51 at both upper and lower ends, bearings 52 and 57 supporting a drive shaft 60, gaskets 53 and 54, clamps 55 and 56, and the like. Since a large number of shims 61 and 62 are interposed therebetween, the clearance of the meshing portion between the bevel gear 72 on the camshaft 71 and the bevel gear 50 at the upper end can be adjusted by increasing the number of shims 61 to be interposed or This is done by reducing the number of shims 61 to be interposed. Adjustment of the clearance between the bevel gear 51 and the bevel gear 73 meshing with the lower end bevel gear 51 is performed by increasing or decreasing the number of shims 62. In addition,
Numerals 63 to 65 also show shims, but these shims are for adjusting the clearance for holding the bearing.

The prior art relating to the shaft driving device is disclosed in Japanese Utility Model Laid-Open No. 63-182201 and Japanese Utility Model Laid-Open No.
There is an apparatus described in JP-A-142394. The former is a device for driving a camshaft, and has a structure in which a dynamic damper is attached to a rod-shaped intermediate gear. The latter is a device for driving rear wheels of a motorcycle, and has a structure in which a propeller shaft connected to a shaft of a rear wheel is connected to a second drive shaft of an engine by spline fitting.

[0004]

However, the above-described conventional shaft drive has room for improvement in the following points. That is, by interposing a thin plate-shaped shim between the bevel gear and its holding member, the clearance of the meshing portion with the bevel gear on the other side is adjusted. It is difficult to adjust and requires skill.

[0005] Since the adjustment work by the shim cannot be performed while the engine is running, the adjustment (engine stop) is performed.
There is a possibility that the clearance may slightly differ between the time and the operation. For this reason, even if the clearance appears to be appropriate at the time of adjustment, when the engine is operated, a tooth contact noise may be generated between the bevel gears.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is possible to easily and continuously adjust a clearance between meshing portions of bevel gears such as a camshaft by an external operation even during operation of an engine. It is an object to provide a shaft drive.

[0007]

In order to achieve the above object, a shaft driving device according to the present invention comprises: A) rotating a driving shaft;
Rolling a pair of bevel gears, a drive shaft, a pair of bevels
Shaft drive that transmits to the rotation driven shaft via the
B) Bevels at both ends of the drive shaft
The bosses of the gears are each extended in the axial direction on the proximal side, and
Slide the bevel gear on the shaft side with respect to the drive shaft.
Sliding in the axial direction via plunge or key engagement
C) around the boss of each bevel gear, through a bearing
And pivotally mount the cylindrical bearing housing,
When a thread is formed on the outer peripheral surface of the bearing housing,
D) The drive shaft and the rotation driven shaft are freely rotatable.
Screw holes communicating with the inside of each housing
And the screw portion of the bearing housing is inserted into the screw hole.
Screwed together, and E) circle so that it can rotate integrally with each bearing housing
Connect the cylindrical cases, and make sure to
Relatively rotatable connection with cylindrical sleeve cover
Cover the shaft and select bearing housings on both sides.
By selectively rotating the drive shaft,
Adjustable clearance of meshing part of bell gear
Make up.

According to the shaft drive device of the present invention having the above configuration, when it is necessary to adjust the clearance of the meshing portion of the bevel gear of the drive shaft end, rotating the bare <br/> ring housing in one direction By doing so, the bevel gear on the drive shaft side advances or retreats with the bearing housing with respect to the other bevel gear, so that the clearance of the meshing portion of the bevel gear at one end of the drive shaft is continuously adjusted according to the rotation direction and rotation angle of the bearing housing. . In addition, if the shaft drive device is arranged on one side of the engine, it can be adjusted by simple external work without disassembling the engine, and it can be adjusted even in the operating state of the engine, so that accurate Can be adjusted.

Also, a bevel gear at one end of the drive shaft
Not only the clear run of the meshing part of the opposite bevel gear
Can be adjusted in the same way. In addition, the drive shaft
And each drive section is covered with a cylindrical case or sleeve cover.
And that dust etc. does not enter the drive unit
It can be installed on one side of the engine and exposed to the outside.
The bevel gear meshes easily even when the engine is running.
The clearance of can be adjusted. Therefore, chains and
Unlike the case where torque is transmitted by a belt,
There is no need to attach the cover directly to the
The degree of freedom of design is high because the placement can be determined relatively freely.
In addition, a design that emphasizes design becomes possible .

[0010]

According to a second aspect of the present invention, the rotation driven shaft can be a camshaft and the drive shaft can be a crankshaft. In the device according to this configuration, since the transmitted torque is relatively small, the overall structure can be simplified and the weight and size can be reduced.

[0012] As according to claim 3, wherein said screwed locking nut loosening the screw portion of the bearing housing, it is desirable to be tightened the nut in contact with the open face of the threaded hole of the housing . In the device with this configuration, the locking nut acts to prevent the loosening of the bearing housing except at the time of adjustment, so that the clearance of the meshing portion of the bevel gear is maintained in the optimum adjustment state for a long time.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a shaft drive device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a partial longitudinal sectional view of an engine, showing an embodiment of a shaft drive device applied to camshaft drive.
2A is an enlarged cross-sectional view of the upper portion of the camshaft driving device of FIG. 1, FIG. 2B is an enlarged cross-sectional view of the lower portion of the camshaft driving device of FIG. 1, and FIG. Partial plan view with the head cover removed, FIG. 4 is III in FIG.
FIG. 5 is a partially enlarged cross-sectional view of the shaft driving device.

As shown in FIGS. 1 to 3, an engine 1 is an air-cooled single overhead cam (SO
HC) 4-valve horizontal 2-cylinder engine. Crankshaft 3 in crankcase 15 below engine 1
The shaft drive device 4 is interposed between the camshaft 2 and the upper part of the camshaft 2 above the cylinder head 14.

The shaft driving device 4 has a drive shaft 5 having spherical splines 5a and 5b formed at both upper and lower ends.
, An upper bevel gear 6 and a lower bevel gear 16. The upper bevel gear 6, as shown in FIG.
Are extended downward in the axial direction, and a large number of vertically linear splines 6c that engage with the spherical splines 5a (FIGS. 1 and 2) protrude from the inner peripheral surface of the lower end of the cylindrical extension 6b. Have been. The cylindrical extension 6b of the bevel gear 6 is a spherical spline 5a (FIG. 1) of the drive shaft 5 (FIGS. 1 and 2).
2), and the bevel gear 6 is mounted on the drive shaft 5 (FIGS. 1 and 2) so as to be slidable in the axial direction and swingable in all directions.

A cylindrical metal bearing housing 7 is rotatably mounted around the cylindrical extension 6b of the bevel gear 6. Upper and lower bearings 8 are fitted in the housing 7, and the inner ring side of the bearing 8 is fitted on the outer peripheral surface of the cylindrical extension 6 b. A screw portion 6d is formed on the outer peripheral surface of the lower end portion of the cylindrical extension portion 6b, and the nut 8 is screwed and tightened, whereby the bearing 8 is sandwiched between the upper end step portion of the cylindrical extension portion 6b, A housing 7 is rotatably mounted around the bevel gear 6. The upper and lower ends are opened, and a vertical intermediate position 10a is formed on a hexagonal surface, and the upper end of the metal cylindrical case 10 whose outer diameter is gradually reduced from the intermediate position 10a to the lower end is formed as the inner periphery of the lower end of the housing 7. Screwed into the screwing portion 7c, and is integrally connected to the housing 7. An annular groove 10c is formed on the outer peripheral surface of the lower cylindrical portion 10b of the cylindrical case 10 in two upper and lower stages. On the outer peripheral surface of the housing 7, a male screw portion 7a is formed except for an upper end portion.

Lower spherical spline 5b (FIGS. 1 and 2)
The lower bevel gear 16 (FIG. 1) meshed with the upper bevel gear 6 also has the same structure as the upper bevel gear 6. Therefore, the description is omitted, and the common members are denoted by reference numerals obtained by adding 10 to the reference numerals of the members of the upper bevel gear 6, and are shown in FIG. A metal cylindrical sleeve cover is provided between the outer peripheral surface of the lower cylindrical portion 10b of the upper case 10 and the outer peripheral surface of the upper cylindrical portion 20b (FIGS. 1 and 2) of the lower case 20 (FIGS. 1 and 2). 21 (FIG. 1)
The sleeve cover 21 (FIG. 1) is connected to the upper case 10 and the lower case 10 via O-rings 22 (FIGS. 1 and 2) loaded in the annular grooves 10c and 20c (FIGS. 1 and 2). The case 20 is connected to the case 20 so as to be relatively rotatable. Therefore, the upper case 10 and the lower case 20 are connected to the sleeve cover 21 so as to be relatively movable, and even if the distance between the upper case 10 and the lower case 20 expands and contracts, the movement is covered (covered). )be able to.

The camshaft 2 is rotatably disposed via a bearing 23 at the center of a camshaft chamber 14A formed above the cylinder head 14 as shown in FIG. A bevel gear 24 is attached to one end (the right end in the figure) of the device by a set screw 25 so as to be integrally rotatable. On the other hand, a bevel gear 34 is attached to one end (right end in the figure) of the crankshaft 3 in the crankcase 15 by a set screw 35 so as to be integrally rotatable. On one side (right side) of the engine 1, a through hole 26 communicating with the inside is formed on the lower surface of the cylinder head 14, and a female screw portion 26 a is formed on an inner peripheral surface of the through hole 26, and the screw hole is formed. Have been. The female screw portion 26a is provided except for an upper end portion 26b in the through hole 26, and an annular groove 26c for loading the O-ring 27 is formed in the upper end portion 26b.
(a)). Similarly, a through-hole 36 communicating with the inside is formed on the upper surface of the crankcase 15, and a female screw portion 36a is formed on the inner peripheral surface of the through-hole 36 to form a screw hole. The female screw portion 36a is provided except for a lower portion 36b in the through hole 36, and an O-ring 3 is provided at an end of the lower portion 36b.
An annular groove 36c is formed for loading the groove 7 (see FIG. 2B).

The upper housing 7 is screwed into the through hole 26 of the cylinder head 14 and the lower housing 17
Is screwed into a through hole 36 of the crankcase 15.
In this state, the teeth of the upper bevel gear 6 of the drive shaft 5 mesh with the teeth of the bevel gear 24 of the camshaft 2, and the teeth of the lower bevel gear 16 match the bevel gear 34 of the crankshaft 3.
Mesh with the teeth. Male screw 7a of upper housing 7
A locking nut 28 is screwed into the lower end of the nut. The nut 28 is integrally provided with a small-diameter cylindrical portion 28a at the upper end. An annular hole 26d corresponding to the small-diameter cylindrical portion 28a is formed on the inner peripheral surface of the opening of the through hole 26, and the nut 28 is tightened in a small diameter. The cylindrical portion 28a fits into the annular hole 26d, and the upper surface of the nut 28 contacts the lower surface of the cylinder head 14 around the through hole 26. Furthermore, in this example, a screw hole 7b penetrating sideways is provided at the lower end of the upper housing 7.
The nut 28 is prevented from loosening by contacting the tip of a set screw 29 screwed into the screw hole 7b with the small-diameter cylindrical portion 28a of the nut 28 (FIG. 2A). reference).

A locking nut 38 is also screwed into the upper end of the male screw portion 17a of the lower housing 17, but this nut 38 is also provided with a small-diameter cylindrical portion 38a, and the nut 38 is tightened. The small-diameter cylindrical portion 38a fits into the annular hole 36d, and the upper surface of the nut 38 is
6 is brought into contact with the upper surface of the crankcase 15 around the periphery of the crankcase 6 (see FIG. 2B).

As shown in FIG. 1, a piston 12 is inserted into a cylinder liner 11A of a cylinder block 11 so as to be slidable in a vertical direction, and the piston 12 is connected to a crankshaft 3 via a connecting rod 13. I have. The cylinder head 14 is provided with two intake ports 40 (FIG. 4) and two exhaust ports 42. As shown in FIGS. 3 and 4, each intake port 40 has an intake valve 41 and each exhaust port 4
In FIG. 2 (FIG. 1), an exhaust valve 43 is disposed so as to be vertically movable, and independent rocker arms 44 for opening and closing the exhaust valve 43 are operated by a rocker shaft 46.
A double rocker arm 45 for opening and closing the intake valve 41 is supported by a rocker shaft 47 so as to be swingable. In FIG. 4, the ignition plug 49 is arranged along a guide pipe 48 whose upper end is inclined toward the exhaust port 42 side.
An ignition part 49a is arranged substantially at the center of the combustion chamber 30 (FIG. 4).

Next, the procedure for adjusting the clearance of the meshing portion of the upper bevel gear 6 in the shaft drive device 4 according to the present embodiment having the above-described configuration will be described.

In FIG. 1, in the operating state or the stopped state of the engine 1, first, the set screw 29 is loosened to make the nut 28 rotatable, and then the nut 28 is loosened using a tool such as a spanner.

The tool is used to fix the hexagonal surface 10 of the cylindrical case 10.
a and slowly rotate to the right or left. When the case 10 is rotated to the right, the upper housing 7 rises while rotating in the through hole 26, so that the clearance between the teeth of the bevel gear 6 and the teeth of the bevel gear 24 of the camshaft 2 becomes narrow, and conversely. When the case 10 is rotated to the left, the teeth of the bevel gear 6 and the camshaft 2 are rotated.
The clearance between the bevel gear 24 and the teeth of the bevel gear 24 is increased.
By rotating the case 10 via the tool in this way, the clearance between the case 10 and the bevel gear 24 can be continuously adjusted, so that the rotation of the cover 10 is stopped in an optimal state.

After the nut 28 is tightened with a tool, the set screw 29 is tightened, and the adjustment operation is completed.

Therefore, the above operations (1) to (4) can be performed in a very short time using a simple tool without disassembling the shaft driving device 4 from outside the engine 1. The clearance of the lower bevel gear 16 can be adjusted in the same procedure as described above.

According to the shaft driving device 4 of the above embodiment, as shown in FIG. 1, the through hole 2 provided on the lower surface of the cylinder head 14 on one side (right side) of the engine 1 is provided.
6 position and orientation (usually vertical) and crankcase 15
When the position and orientation (usually vertical) of the through hole 36 provided on the upper surface of the drive shaft 5 do not match due to machining errors, assembly errors, etc., the spherical splines 5a and 5b at the upper and lower ends of the drive shaft 5 and the upper bevel gear 6 The lower bevel gear 16 is absorbed by the meshing portion with the splines 6c (FIG. 5) and 16c, and the upper and lower bevel gears 6 and 16 are meshed with the opposing bevel gears 24 and 34 in an optimal state.

Although the embodiment for driving the camshaft has been described above, the shaft driving device of the present invention is not limited to the driving of the camshaft 2 as in the above-described embodiment, but also drives the rear wheel of the motorcycle. Also apply for. In this case, since the transmitted rotational driving force is large, the outer diameter of the drive shaft, bevel gear, etc. is enlarged to increase the strength, and the drive shaft is divided at an intermediate position in the longitudinal direction, and a universal joint is provided. Since other structures are common, illustration is omitted.

Further, in the above-described embodiment, the spherical splines 5a and 5b are interposed at the connecting portions between the upper and lower ends of the drive shaft 5 and the bevel gears 6 and 16, but may be replaced with a linear spline structure. An engagement structure between a key and a key groove may be used. In short, the bevel gears 6 and 16 may be connected to the upper and lower ends of the drive shaft 5 slidably in the axial direction, respectively.

[0031]

[0032]

As is apparent from the above description,
The shaft driving device of the present invention has the following excellent effects.

(1) The clearance between the meshing portions of the bevel gears such as the camshaft and the rear wheel axle can be easily and continuously adjusted by an external operation even during the operation of the engine.

In addition, since the clearance can be adjusted even in the operating state of the engine, the clearance of the meshing portion of the bevel gear can be adjusted to an optimum state, and the clearance of the meshing portion of the bevel gear can be continuously changed by rotating the bearing housing. As a result, the adjustment work can be performed.

(2) Further, the clearances of the meshing portions of the bevel gears at both ends of the drive shaft can be adjusted in the same manner.

Further , since the driving section is covered with the case or the sleeve cover, dust and the like do not enter the driving section. Therefore, the bevel gear can be easily exposed to the outside of the engine, so that the clearance of the meshing portion of the bevel gear can be easily adjusted without disassembling the engine even in the operating state of the engine, and the design flexibility is high. The layout can be designed in consideration of the design.

(3) In the apparatus according to the second aspect , since the transmitted torque is relatively small, the overall structure can be simplified, and the weight and size can be reduced.

(4) In the device according to the third aspect , since the loosening of the bearing housing is prevented by the locking nut except during the adjustment, the clearance of the meshing portion of the bevel gear is maintained in an optimum state for a long time after the adjustment. Is done.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of an engine, showing an embodiment of a shaft drive device of the present invention applied to camshaft drive.

2 (a) is an enlarged sectional view of an upper portion of the camshaft driving device of FIG. 1, and FIG. 2 (b) is an enlarged sectional view of a lower portion of the camshaft driving device of FIG.

FIG. 3 is a partial plan view of the engine of FIG. 1 with a head cover removed.

FIG. 4 is a sectional view taken along line III-III of FIG. 3;

FIG. 5 is a partially enlarged sectional view of the shaft driving device of FIG. 1;

FIG. 6 is an exploded perspective view showing a conventional general shaft driving device for driving a camshaft.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Camshaft 3 Crankshaft 4 Shaft drive device 5 Drive shaft 5a / 5b Spherical spline 6.16 / 24/34 Bevel gear 7.17 Bearing housing 8.18 Bearing 10.20 Cylindrical case 21 Cylinder head 22 Crank case 26・ 36 Through hole (Screw hole) 27 ・ 37 O-ring 28 Locking nut

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01L 1/02 F02B 67/04 F16H 55/17 F16H 55/20 F16H 57/12 F16D 3/84

Claims (3)

(57) [Claims] A rotation of a drive shaft is controlled by a pair of bevel gears and a drive.
Eve shaft, rotating driven shaft via a pair of bevel gears
In the shaft drive device having the structure that transmits, its boss portion of the bevel gear at both ends of the drive shaft
Each extends in the axial direction on the proximal side, and is attached to the drive shaft.
On the other hand, the shaft side bevel gear is
Are connected slidably in the axial direction via a joint, and a cylindrical bearing is mounted around the boss of each bevel gear via a bearing.
The ring housing is mounted rotatably and the bearing housing
A screw portion is formed on the outer peripheral surface of the housing, and
Each how to rotatably support a driving shaft and the rotation driven shaft
A screw hole communicating with the inside is provided for the jing, and the screw hole
Screw the threaded part of the bearing housing into each bearing.
The cylindrical case so that it can rotate integrally with the housing.
And a cylindrical sleeve cover between the proximal ends of each case.
The drive shaft is connected rotatably by a bar.
And selectively rotate the bearing housings on both sides.
Clear run of the meshing part of the bevel gears at both ends of the shaft
A shaft drive device characterized in that each of the shaft drives can be adjusted . 2. The shaft drive device for driving a camshaft according to claim 1 , wherein the rotation driven shaft is a camshaft, and the drive shaft is a crankshaft. 3. A screwed locking nut loosening the screw portion of the bearing housing, and the nut on the opening surface of the screw hole of the housing to be clamped in contact 請
3. The shaft drive device according to claim 1 or 2 .