JP2001187956A - Backlash regulating mechanism for gear of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a backlash regulating mechanism for gear of engine having satisfactory assembling property and minimized in backlash noise and whine noise. SOLUTION: In this backlash regulating mechanism for gear of engine for regulating the backlash between an output taking out reduction small gear 10c formed on a crankshaft 5 and a reduction large gear 15 installed to a clutch mechanism 14 and meshed with the reduction small gear 10c, the reduction large gear 15 is divided into an output transmitting main gear 26 and a sub-gear 27 supported by a spring so as to be relatively rotatable to the main gear 26, and the main gear 26 and the reduction small gear 10c are partitioned into a plurality of dimensional sections on the basis of base tangent length. This mechanism further comprises a scissors mechanism for mutually meshing the main gear 26 and the reduction small gear 10c within the same dimensional section and energizing the rotation of the reduction small gear in the nipping direction by the sub-gear 27 and the main gear 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for adjusting the backlash between a small reduction gear and a large reduction gear employed in an engine suitable for a motorcycle, for example.

[0002]

2. Description of the Related Art For example, in a motorcycle engine, engine rotation is transmitted from a crankshaft to a clutch mechanism and a transmission mechanism via a reduction gear and a reduction gear. When the reduction gear on the crankshaft side is engaged with the reduction gear on the clutch mechanism side, the rattling noise can be reduced by setting a small backlash in the design, but if the backlash is made too small, assembly becomes difficult. On the other hand, a problem arises that the beat sound becomes loud. That is, even if the gears are within the specified dimensional tolerance, for example, if the gears manufactured on the maximum plus side within the tolerance are combined, problems such as difficulty in assembling and increase in humming noise occur.

Therefore, the backlash between the large reduction gear and the small reduction gear is set large so that assembly is possible even when the worst combination described above is selected, thereby ensuring assemblability. A scissor mechanism for dividing the large reduction gear into an output transmission main gear and a sub gear, and urging the sub gear with the main gear in a direction sandwiching the small reduction gear; and providing the large backlash with a scissors mechanism. It is conceivable to reduce the rattling sound by absorbing the noise.

[0004]

However, in the case of the above-described mechanism in which the backlash is set to be large and the backlash is absorbed by the scissors mechanism, it has been found that a problem arises that the beat sound becomes large particularly in a high-speed rotation region. . This is due to the large backlash,
It is necessary to increase the amount of urging by the scissors mechanism, that is, the amount of relative movement between the main gear and the sub gear. Therefore, it is necessary to increase the urging spring of the scissors mechanism with a large spring load. It is considered that the loud sound is the cause of the beat sound.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a mechanism for adjusting the backlash of an engine gear that has good assemblability and has little rattle and hum.

[0006]

According to a first aspect of the present invention, there is provided a backlash between an output extraction reduction gear formed on a crankshaft and a reduction gear which is mounted on a clutch mechanism and meshes with the reduction gear. In the backlash adjustment mechanism of the gear of the engine to be adjusted, the reduction gear is divided into an output transmission main gear and a sub gear that is rotatably supported relative to the main gear, and the main gear and the reduction gear are A scissors that divides the gear into a plurality of size sections based on the mating tooth thickness, meshes the main gear and the reduction gear in the same size section, and urges the sub gear to rotate in a direction to sandwich the reduction gear with the main gear. It is characterized by having a mechanism.

According to a second aspect of the present invention, in the first aspect, the main gear and the sub gear are formed with an assembling hole having an axis coincident when the teeth of the sub gear are included in the projection plane of the teeth of the main gear. When the gear is engaged with the reduction gear, an assembling jig is inserted into the two matching holes.

A third aspect of the present invention is characterized in that, in the first or second aspect, the tooth thickness of the sub gear is set smaller than the tooth thickness of the main gear.

[0009]

According to the first aspect of the invention, the main gear and the reduction pinion are divided into a plurality of dimensional sections based on the thickness of the mating teeth, and the main gear and the reduction pinion in the same dimensional section are separated. Since the backlash is designed to be meshed, the backlash is considerably smaller than the size according to the above-described dimensional division, that is, as compared with the case where the backlash is increased in order to secure the above-described assemblability, so that the urging amount in the scissor mechanism can be reduced, and The biasing spring can have a small spring load, and as a result, a beat sound can be suppressed.

According to the second aspect of the present invention, the main gear and the sub gear are formed with an assembling hole whose axis coincides with each other when the teeth of the sub gear are included in the projection plane of the teeth of the main gear. In the assembling operation, the sub-gear is included in the projection plane of the main gear by inserting the assembling jig into the two matching holes, so that the sub-gear does not interfere with the reduction pinion, and Assembly work can be easily performed.

According to the third aspect of the present invention, since the tooth thickness of the sub-gear is set smaller than the tooth thickness of the main gear, the above-described assembling operation can be performed without significantly increasing the positional accuracy of the assembling holes for the main gear and the sub-gear. Performance can be improved. That is, when the tooth thicknesses of the two gears are the same, if the positional accuracy of the two matching holes is low, the sub gear may interfere with the reduction small gear, and the assembling workability is reduced. Since the tooth thickness is set to be thin, the sub gear does not interfere with the small reduction gear even if the position accuracy of the two alignment holes is low to some extent, and assembling workability can be secured.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 to 13 are views for explaining a backlash adjusting mechanism for an engine gear according to an embodiment of the present invention. FIG. 1 is a cross-sectional plan view showing the periphery of a clutch mechanism having the backlash adjusting mechanism. Figure, Figure 2, Figure 3
4 is a cross-sectional plan view of the clutch mechanism, a partial cross-sectional front view, FIG. 4 is a front view of the scissors mechanism portion, FIGS. 5 and 6 are cross-sectional views taken along lines VV and VI-VI in FIG. 4, FIGS. 9 and 10 are front and sectional side views of a sub gear, FIGS. 11 and 12 are front and sectional side views of a main gear, and FIG. 13 is a side view showing an assembly jig. FIG.

In FIG. 1, reference numeral 1 denotes a cylinder block of a parallel four-cylinder engine mounted on a vehicle body with a crankshaft directed in a vehicle width direction. First to fourth pistons 3a to 3d are slidably inserted into cylinder bores 2a to 2d of the first to fourth cylinders formed in the cylinder block 1, and each of the pistons 3a to 3d is connected to a connecting rod 4a. Through 4d are connected to the first to fourth crank pins 6a to 6d of the crankshaft 5. The first to fifth journal portions 7a to 7e of the crankshaft 5 include first to fifth journal bearings 8a to 8 formed on the cylinder block 1 side and the crankcase side.
e.

The crankshaft 5 is of a forging-integral molding type, and the first to fourth journal portions 7a to 7e and the first to fourth crankpins 6a to 6d are connected to a first to fourth crank web pair. 9 to 12, and the first to fourth crank web pairs 9 to 12 are left and right crank webs 9a, 9b, 10a, 10b, 11a, respectively.
11b, 12a and 12b.

The right crank web 10b of the second pair of crank webs 10 located on the right side of the center line C of the crankshaft 5 in the engine width direction is formed in a disk shape. Is formed. And the above reduction gear 1
0c meshes with a large reduction gear 15 of a clutch mechanism 14 mounted on a transmission main shaft 13 constituting the transmission.

The reduction gear 15 is provided with a needle bearing 16
And is rotatably supported by the speed change main shaft 13 via a spacer 17. The reduction gear 15 is rotatably disposed between the bottom surface of the bottomed cylindrical outer housing 18 of the clutch mechanism 14 and the annular cover plate 19. The cover plate 19 includes three rivets. 20 press-fixes the boss portion 18a projecting from the bottom surface.

The clutch mechanism 14 has a bottomed cylindrical inner housing 21 disposed inside the outer housing 18 with its opening facing outward.
A large number of annular inner clutch plates 22 are arranged on the outer periphery of the inner clutch plate 22, and the convex portion formed on the inner periphery of the inner clutch plate 22 is engaged with the engaging groove 21 a recessed on the outer periphery of the inner housing 21. A number of annular outer clutch plates 23 are arranged on the inner periphery of the outer housing 18, and a protrusion formed on the outer periphery of the outer clutch plate 23 is formed by a locking slit 18 b formed on the outer housing 18.
And the outer clutch plate 23 and the inner clutch plate 22 are alternately positioned, and these clutch plates 22 and 23 are connected to each other by the clutch spring 2.
4 has a schematic structure pressed through a pressing plate 25.

A support hole 18e formed in the axis of the outer housing 18 is rotatably supported by a boss 26b of a main gear 26 constituting the large reduction gear 15. A coupling hole 21b formed in the shaft center of the inner housing 21 is spline-fitted to the outer peripheral surface of the transmission main shaft 13. 26 is a push rod,
When the clutch lever attached to the steering handle is gripped, the push rod 26 moves rightward, moving the pressing plate 25 rightward, and the pressing force acting on the clutch plates 22, 23 is released. The clutch mechanism 14 is turned off.

The large reduction gear 15 is composed of a main gear 26 for transmitting a rotational force and a sub gear 27 for absorbing backlash. This sub gear 27
Is formed by forming sub-teeth 27b of a predetermined specification on the outer periphery of an annular disk having a mounting hole 27a in the axis thereof. One urging spring opening 27c, five damper spring openings 27d and 3
One boss hole 27e is formed. In the vicinity of the biasing spring opening 27c, a matching hole 27f into which the assembly jig T is inserted at the time of assembly work is formed. The alignment hole 27f is formed by a straight line B passing from the axis C of the sub gear to the center of the alignment hole 27f and a straight line A passing from the axis C to the urging spring opening 27c and the circumferential center of the sub tooth 27b. The angle is θ and the radius is R.

In the main gear 26, a support boss portion 26b having a support hole 26a in the shaft center and an annular rim portion 26d having main teeth 26c of a predetermined specification formed on an outer peripheral surface are integrally connected by a flat plate portion 26e. Like the sub gear 27, one urging spring opening 26f, five damper spring openings 26g, and three boss holes 26h are formed. In the vicinity of the biasing spring opening 26f, a matching hole 26i for inserting the assembly jig T at the time of assembly work is formed. The matching hole 26i has the same diameter and the same position as the matching hole 27f of the sub gear 27, that is, the straight line B
Is formed at a position where the angle formed by the straight line A and the radius A is θ.

Here, the main teeth 26 of the main gear 26
“c” is formed in a gear specification having a tooth thickness that provides a certain degree of backlash to the above-described reduction small gear 10c. On the other hand, the sub-teeth 27b of the sub-gear 27 are formed so that the tooth thickness thereof is smaller than the main teeth 26c of the main gear 26 by an area hatched in FIG. That is, as shown in FIG.
When the center of the sub gear 27 in the thickness direction of the sub gear 27 coincides with the center of the sub gear 27, the sub tooth 27 b of the sub gear 27 is hidden in the projection plane of the main tooth 26 c of the main gear 26.

The bottom surface of the outer housing 18
A damper spring support recess 18c is formed in a portion of the sub gear 27 and the main gear 26 facing the damper spring openings 27d and 26g in an arc shape as shown in FIG. 2, and the damper spring of the annular cover plate 19 is formed. A damper spring guide portion 19a is formed at a portion facing the support concave portion 18c so as to raise an edge of a circumferential side of the opening 19b outward. The damper spring guide 19a and the damper spring support recess 18c form a damper spring support space having a circular cross section as a whole.

A damper spring 28 is disposed in a space surrounded by the damper spring support recess 18c, the damper spring guide 19a and the damper spring opening 26g of the main gear 26. One end 28a and the other end 28b of the damper spring 28 are engaged with the edges of the one end 26g 'and the other end 26g''of the main gear 26 in the circumferential direction of the damper spring opening 26g. The other end 2 of the spring 28
8b is the other end 18c '' of the damper spring support concave portion 18c.
Is in contact with

From the reduction small gear 10c to the main gear 26
When there is a large fluctuation in the engine torque inputted to the outer housing 1 of the clutch mechanism 14,
8, the damper spring 28 contracts due to the movement, thereby absorbing the torque fluctuation and smoothing the driving torque. The arrow c indicates the rotation direction of the reduction gear 15. Further, with the relative movement of the main gear 26, the support boss 18a of the outer housing 18 relatively moves within the boss hole 26h of the main gear 26 and the boss hole 27e of the sub gear 27.

The bottom of the outer housing 18
An urging spring disposing recess 1 is provided at a portion of the sub gear 27 and the main gear 26 which faces the urging spring openings 27c and 26f.
8d is recessed, and a biasing spring guide portion 19c is provided at a portion of the annular cover plate 19 facing the biasing spring disposing recess 18d so as to raise an edge of a circumferential side of the opening 19d outward. It is formed. Note that the biasing spring disposition recess 18d of the present embodiment is the same as the damper spring support recess 18c.
And the biasing spring guide 19c has the same shape and size as the damper spring guide 19a. Therefore, the combination angular position of the outer housing 18, the cover plate 19, and the reduction gear 15 can be freely selected as long as the boss 18a and the boss holes 26h, 27e coincide.

The main gear 26 and the sub gear 27
The urging spring 29 is disposed in a space surrounded by the urging spring openings 26f and 27c, the urging spring disposing recess 18d, and the guide portion 19c. One end 29 of this biasing spring 29
a, the other end 29b is connected to one end 26f ', 27 in the circumferential direction of the biasing spring opening 26f, 27c via the spacer 30a, 30b.
c 'and the other end 26f ", 27c".

In this way, a scissors mechanism for sandwiching the small reduction gear 10c between the main gear 26 and the sub gear 27 constituting the large reduction gear 15 is provided, and the small reduction gear 10c is formed by the two gears 26 and 27. By sandwiching, the backlash between the main gear 26 and the reduction small gear 10c is substantially absorbed.

The spacers 30a and 30b function as spring seats for supporting the biasing spring 29,
It also functions as a balance weight for adjusting the weight imbalance of the clutch mechanism 14. That is, in the present embodiment, a structure is adopted in which one of the six damper springs 28 is a biasing spring 29 for a scissors mechanism. Although the biasing spring 29 is set to have the same outer diameter as the damper spring 28, the wire diameter and the spring length are set to be small, and the weight is accordingly reduced. Therefore, there is a risk that the weight balance will be lost if it is used as it is. In this embodiment, the weight shortage caused by the urging spring 29 is removed by the spacers 30a and 30a.
The weight is balanced by supplementing with b.

In assembling the portion including the crankshaft 5, the clutch mechanism 14, and the transmission main shaft 13 in the engine of this embodiment, the size of the reduction gear 10c and the main gear 26 are adjusted in advance. Specifically, the reduction pinion 10c confirmed to be within the manufacturing tolerance range
And the thickness of the mating tooth of the main gear 26 is measured, and the measurement result is divided into, for example, five stages of dimensions A to E. The reduction gear in the A section is combined with the main gear in the A section, and similarly, the B section is divided. , And the reduction gears and main gears of the C sections are combined. The thickness of the mating tooth means a dimension measured over a predetermined number of mating teeth, for example, eight teeth.

When the clutch mechanism 14 with the above-described reduction gear 15 is mounted on the transmission main shaft 13, first, an assembling jig T formed by forming a tapered guide portion a at the tip of a round bar is used. The main gear 26 and the sub gear 27 are pushed into the matching holes 26i and 27f. Then, the main gear 26 and the sub gear 27 relatively rotate slightly while compressing the urging spring 29, and the teeth 26c, 27b of the gears 26, 27 are rotated.
Overlap (see FIGS. 3 and 7). In this state, the clutch mechanism 14 is mounted on the transmission main shaft 13, and the teeth 26 of the main gear 26 are
c is engaged with the reduction small gear 10c.

After mounting the clutch mechanism 14, the assembling jig T is removed. Then main gear 2
6, the sub-gear 27 is relatively rotated by the urging force of the urging spring 29 in a direction in which one end and the other end of the urging spring openings 26f and 27c coincide with each other.
The tooth surfaces a 'and b' of the reduction small gear 10c are sandwiched by the tooth surfaces a and b of the main teeth 26c and the sub teeth 27b, and as a result, backlash is absorbed. Arrow c indicates the direction of rotation of the large reduction gear 15 as described above. Therefore, the drive surface a 'of the small reduction gear 10c drives the tooth surface a of the main tooth 26c and drives the sub tooth 27b. Above the tooth surface b sandwiches the non-drive surface b 'of the reduction small gear 10.

As described above, in this embodiment, the reduction small gear 1
The main gear 26 constituting the reduction gear 15 with the tooth surface of 0c
Between the main gear 26c and the reduction gear 1
The backlash between the backlash and 0c can be absorbed, and rattling due to the backlash can be prevented. In FIG. 8, the tooth surface b 'of the reduction gear 10c on the pitch circle p is shown.
It can be seen that the gap between the gear and the tooth surface 26c 'of the main gear 26c is the backlash s, and the backlash s is absorbed by the tooth surface c of the sub gear 27b abutting on the tooth surface b'.

In this embodiment, the reduction gear 10c
And the size of the main gear 26 are adjusted to combine the reduction small gear and the main gear in the same dimensional section, so that the actual backlash falls within a predetermined range, and therefore the backlash becomes too small and assembly becomes impossible. Nothing happens.

Further, in the present embodiment, as compared with the case where the backlash is set relatively large to ensure the assemblability and the large backlash is absorbed by the scissors mechanism, the relative position between the main gear and the sub gear in the scissors mechanism is reduced. The rotatable angle (relative movement amount) can be set small, so that it is not necessary to increase the spring load of the biasing spring.
As a result, it is possible to avoid an increase in beat noise caused by a large spring load.

In this embodiment, when the large reduction gear 15 is meshed with the small reduction gear 10c, the assembly jig T is inserted into the engagement hole 26i of the main gear 26 and the engagement hole 27f of the sub-gear 27 to thereby form the main teeth 26c. And sub tooth 2
7b, the sub teeth 27b of the sub gear 27 do not interfere with the reduction small gear 10c at the time of the meshing, and the assembling is easy.

In this embodiment, the thickness of the sub-teeth 27b is set smaller than that of the main teeth 26c so that the sub-teeth 27b are hidden within the projection plane of the main teeth 26c. Hole 27f
, Specifically, the dimensional accuracy of the two matching holes 26i and 27f shown in FIGS. 9 and 11 with respect to the angle θ and the radius R can be reduced. That is, when the tooth thickness of the sub-tooth 27b is the same as the tooth thickness of the main tooth 26c, the sub-tooth 27b tends to interfere with the reduction gear 10c if the position accuracy of the alignment hole is low. In the present embodiment, since the tooth thickness is set to be thin as shown by hatching in FIG. 7, even if the positional accuracy is low, the sub-tooth 27b does not easily interfere with the reduction small gear 10c.

In this embodiment, the outer diameters of the biasing spring 29 and the damper spring 28 are set to be the same, and the biasing spring disposing recess 18d of the outer housing 18 and the damper spring supporting recess 18c have the same shape. Since the urging spring guide 19c and the damper spring guide 19a of the cover plate 19 have the same shape and the same size, the combined angular position of the outer housing 18, the cover plate 19 and the reduction gear 15 is As long as the boss portion 18a and the boss holes 26h and 27e coincide with each other, the selection can be made freely, so that the assembling workability can be improved accordingly.

In the above embodiment, when the thickness of the sub teeth 27b of the sub gear 27 is reduced, both the front and rear teeth surfaces in the rotation direction of the sub teeth 27b are ground, but only one of them is ground. It may be thin. In this case, when the tooth surface b '' on the rear side in the rotational direction is ground, the tooth surface b '' does not contact the reduction small gear 10c, which is advantageous in that the finishing accuracy of the tooth surface can be reduced.

[Brief description of the drawings]

FIG. 1 is a developed cross-sectional plan view around a clutch mechanism having a backlash adjusting mechanism according to an embodiment of the present invention.

FIG. 2 is a sectional plan view of the clutch mechanism.

FIG. 3 is a partially sectional front view of the clutch mechanism.

FIG. 4 is a front view of a scissors mechanism of the backlash adjusting mechanism.

FIG. 5 is a sectional view taken along line VV of FIG. 4 showing the scissors mechanism.

FIG. 6 is a sectional view taken along the line VI-VI of FIG. 4, showing the scissors mechanism;

FIG. 7 is a schematic enlarged view showing a tooth surface shape of the scissors mechanism.

FIG. 8 is a schematic enlarged view showing a tooth surface shape of the scissors mechanism.

FIG. 9 is a front view of a sub gear of the scissors mechanism.

FIG. 10 is a sectional side view of a sub gear of the scissors mechanism.

FIG. 11 is a front view of a main gear of the scissors mechanism.

FIG. 12 is a sectional side view of a main gear of the scissors mechanism.

FIG. 13 is a side view showing an assembly jig.

[Explanation of symbols]

 Reference Signs List 5 crankshaft 10c reduction gear 14 clutch mechanism 15 reduction gear 26 main gear 26i, 27f fitting hole 27 sub gear T assembly jig

Claims (3)

[Claims] An engine gear backlash adjusting mechanism for adjusting the backlash between an output take-out reduction gear formed on a crankshaft and a reduction gear that is mounted on a clutch mechanism and meshes with the reduction gear. The reduction gear is divided into a power transmission main gear and a sub-gear that is rotatably supported relative to the main gear, and the main gear and the reduction gear are divided into a plurality of dimensional sections based on a mating tooth thickness. The engine is characterized in that a scissors mechanism is provided which divides the main gear and the reduction gear in the same dimensional section into mesh with each other, and urges the sub-gear with the main gear in a direction to sandwich the reduction gear. Gear backlash adjustment mechanism. 2. The main gear and the sub-gear according to claim 1, wherein the main gear and the sub-gear are formed with assembling holes whose axes coincide with each other when the sub-gear teeth are included in the projection plane of the main gear teeth, and the main gear meshes with the reduction gear. A backlash adjusting mechanism for an engine gear, wherein an assembling jig is inserted into the two matching holes at the time of the adjustment. 3. The mechanism according to claim 1, wherein a tooth thickness of the sub gear is set smaller than a tooth thickness of the main gear.