JP3198461B2 - Transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission suitable for a motorcycle. In particular, the present invention relates to a so-called integrated transmission gear having two sets of meshing teeth. The present invention relates to an improvement in the structure of a speed change gear capable of realizing many speed ratios without increasing the speed ratio.

[0002]

2. Description of the Related Art A transmission used in a motorcycle or the like includes a primary transmission gear mounted on a primary transmission shaft (main shaft) to which engine rotation is input, and a rear wheel after shifting the rotation. A secondary transmission gear mounted on a secondary transmission shaft (drive shaft) that outputs to the side is meshed, and the rotational speed of the engine is shifted by a gear ratio (speed ratio) of the two gears. Have been. Conventionally, as a transmission gear of such a transmission, a shift groove into which a shift fork is inserted is conventionally provided with two sets of meshing teeth having different numbers of teeth, which are serrated and connected to a transmission shaft. Have,
There is a so-called integrated transmission gear. In addition, the above-mentioned transmission gear,
The shift fork has dog claws on both end surfaces, and the shift fork moves the transmission gear, whereby the dog pawl is locked to the adjacent transmission gear, and as a result, the adjacent transmission gear is moved relative to the transmission shaft. It can be fixed.

[0003]

In the case of a motorcycle for racing, for example, the speed ratio of the above-mentioned transmission is set to a desired value such as a high-speed type or a torque-oriented type depending on various running conditions such as course characteristics and weather. May be changed. In order to change the gear ratio, the primary and secondary gears are changed to have different numbers of teeth. However, in order to change the gear ratio when the above-mentioned integrated transmission gear is provided, the entire transmission gear must be replaced even if the number of teeth of one of the meshing teeth is changed. Therefore, it is necessary to prepare a great variety of integrated transmission gears in accordance with the gear ratio expected to be selected, which is problematic in practice.

[0004] Further, it is required to reduce the size of the transmission. To meet this demand, it is necessary to reduce the interval between the transmission gears. However, in the case of the above-mentioned integrated transmission gear,
Since there are two sets of meshing teeth with different numbers of teeth, it is necessary to provide a gap that can avoid interference between the tool and the mating meshing tooth in each gear cutting process, and therefore, there is a limit to miniaturization. is there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and it is possible to reduce the types of transmission gears to be prepared while securing a large number of changeable transmission ratios, and to avoid tool interference during gear cutting. It is an object of the present invention to provide a transmission that can be used.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a transmission gear having a cylindrical shape and having first and second meshing teeth on an outer peripheral surface and female serrations on an inner peripheral surface is meshed with a male serration of a transmission shaft. The transmission gear is mounted so as to be slidable in the axial direction and to rotate together with the transmission shaft.
In a transmission having a shift groove into which a shift fork is inserted between second meshing teeth, the transmission gear is divided into a first gear having the first meshing teeth and a second gear having the second meshing teeth. Then, external gear-shaped external locking teeth are formed on the outer peripheral surface of the first boss portion of the first gear, and internal tooth-shaped internal locking teeth are formed on the inner peripheral surface of the second boss portion of the second gear. In the state where the first and second gears are disengaged from the transmission shaft, the outer locking teeth are positioned so as to be located between the inner locking teeth, and are relatively moved in the axial direction. After that, the first and second gears are integrated by locking the outer and inner locking teeth so as to prevent relative movement in the axial direction by relative rotation about the axis, and A second gear is mounted on the transmission shaft, and the shift groove is formed between the first and second boss portions.

[0007]

When assembling the transmission gear of the present invention to the transmission shaft, the first and second gears are removed from the transmission shaft, and the teeth of the external locking teeth are interposed between the teeth of the internal locking teeth. After being positioned so as to be positioned and relatively moved in the axial direction, the outer and inner locking teeth are locked so as to prevent the relative movement in the axial direction by relatively rotating about the axis, so that the first and second teeth are locked. The two gears are integrated, and the integrated first and second gears are mounted on the speed change shaft.

As described above, in the transmission according to the present invention, since the transmission gear is divided into the first and second gears, the first and second gears having different numbers of teeth are required to cope with various speed ratios. May be prepared, and the first and second gears may be appropriately selected and combined as needed. In other words, it is possible to solve the problem that when changing the number of teeth of one of the meshing teeth, it is necessary to change the number of teeth of the other meshing tooth as in the case of the conventional integrated speed change gear. The number of types of transmission gears to be prepared is extremely small. Further, since the gears are divided into the first and second gears, the problem of tool interference does not occur in the gear cutting. Therefore, the width of the gears can be reduced as required, and the above-described demand for miniaturization is satisfied. be able to. Furthermore, after the first and second gears are relatively moved in the axial direction and then relatively rotated, the first and second gears can be prevented from separating from each other in the axial direction. An increase in the number of points and assembly steps can be avoided.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to 3 are views for explaining a transmission according to an embodiment of the present invention. FIG. 1 is a sectional side view of a transmission gear, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. It is sectional drawing of a transmission.

In FIG. 1, reference numeral 1 denotes a transmission for a motorcycle. The transmission 1 transmits a rotation of a crankshaft via a clutch mechanism to a main shaft 2 and a rotation after the transmission via a drive chain. It comprises a drive shaft 3 for outputting to the rear wheels, and a six-speed transmission gear train mounted on the two shafts 2 and 3.

The drive shaft 3 has a cylindrical shape having a male serration 3a on its outer periphery, and both left and right ends in the figure are rotatably supported. A drive-side first speed gear 5, a sixth speed gear 6, a fourth speed gear 7, a third speed gear 8, a fifth speed gear 9, and a second speed gear 10 are mounted on the drive shaft 3 in order from the right end in the figure. Have been. The first, fourth, third, and second speed gears 5, 7, 8, and 10 are mounted on the drive shaft 3 via a slide bearing 4 so as to be rotatable and immovable in the axial direction. The sixth and fifth gears 6 and 9 have female serrations 6a and 9a meshed with the male serrations 3a, so that they can rotate together with the drive shaft 3 and slide in the axial direction. Has become.

Dog claws 6b, 9b project from both ends of the sixth and fifth gears 6 and 9, which are slidable in the axial direction, and a shift groove 6 into which a shift fork is inserted is provided on the outer peripheral surface thereof.
c, 9c are formed. The sixth and fifth gears 6,
When the shift fork 9 is slid in the axial direction by the shift fork, one of the dog claws 6b, 9b is rotated by the rotatably supported first, fourth, third, and second gears 5, 7, and 8. , 10 are engaged with any of the dog holes 5a, 7a, 8a, 10a to fix the gear to the drive shaft 3.

The main shaft 2 is a cylindrical member having a male serration 2a on the outer periphery, and the left end and the right side in the figure are rotatably supported. A main-side first speed gear 11 is integrally formed with the main shaft 2 at the right end in the figure.
The speed gear 12, the third / fourth speed gear 13, the fifth speed gear 14, and the second speed gear 15 are mounted, and each mesh with the corresponding speed change gear on the drive side. 6th speed, 5th
The speed gears 12 and 14 are rotatable via a slide bearing 4, and the second speed gear 15 rotates with the main shaft 2 when its female serration 15a meshes with the male serration 2a. It is immovable in the direction. In addition, 12a and 14a are dog claws.

The third and fourth speed gears 13 rotate together with the main shaft 2 and are slidable in the axial direction. The third and fourth speed gears 13 have meshing teeth 16e. It is divided into a third speed gear 16 and a fourth speed gear 17 having meshing teeth 17e. An external gear-shaped external locking tooth 16b is provided on the distal end of the outer periphery of the boss 16a of the third speed gear 16.
Are formed integrally, and an internal locking tooth 17b in the form of an internal gear is integrally formed on the inner surface of the boss 17a of the fourth speed tooth 17. The internal locking teeth 17b of the fourth speed gear 17
External locking teeth 16b of the third speed gear 16
Are locked on the outer surface in the axial direction, whereby the third speed gear 16 and the fourth speed gear 17 are integrated in the axial direction,
Therefore, they move together in the axial direction.

A dog claw 16c is provided at the left end of the third speed gear 16 in the figure, and a dog claw 1c is provided at the right end of the fourth speed gear 17 in the figure.
7c is integrally formed. Further, a shift groove 18a is formed by the outer peripheral surface of the boss portion 16a of the third speed gear 16 and the outer peripheral surface of the boss portion 17a of the fourth speed gear 17, and a shift fork 18 is provided in the shift groove 18a. Is inserted and locked.

Next, the operation and effect of this embodiment will be described. In the transmission of this embodiment, when changing the gear ratio by replacing the third and fourth gears 13 with gears having different numbers of teeth, first remove the second and fifth gears 15 and 14 from the main shaft 2. Then, the third and fourth gears 13 are removed in a combined state. Then, the third and fourth speed gears 16 and 17 are relatively rotated to release the engagement between the outer locking teeth 16b and the inner locking teeth 17b, and the third and fourth speed gears 16 and 17 are rotated.
In the axial direction. And the third and fourth speed gear 1
6, 17 is replaced with a gear corresponding to the desired gear ratio, and the third and fourth gears are engaged by locking the outer locking teeth and the inner locking teeth in the reverse order. Integrated, this is the main shaft 2
Attach to

The shift operation involving the third and fourth gears 13 will be briefly described.
Is moved rightward in the figure, this pushes the boss portion 17a of the fourth speed gear 17 to move the third and fourth speed gears 13 rightward, whereby the dog pawl 17c of the fourth speed gear 17 is moved to the sixth position.
The sixth speed gear 12 is engaged with a dog claw 12a of the speed gear 12.
Are fixed to the main shaft 2. As a result, main shaft 2
Is transmitted to the drive shaft 3 via the main-side sixth speed gear 12 and the drive-side sixth speed gear 6, and further transmitted from the drive chain to the rear wheels. Also, the shift fork 18
Is moved to the left, the boss 1 of the third speed gear 16
6a to move the third and fourth speed gear 13 to the left,
Thus, the fifth speed gear 14 is fixed to the main shaft 2, and the rotation of the main shaft 2 is transmitted from the drive shaft 3 to the rear wheels via the fifth speed gears 14 and 9.

As described above, in the present embodiment, the third and fourth gears 1
3 is divided into a third speed gear 16 and a fourth speed gear 17, and the outer locking teeth 16b and the inner locking teeth 17b are locked so that they can be integrated. 16,
Most gear ratios can be realized by preparing a predetermined number of fourth speed gears 17 having different numbers of teeth and combining them appropriately. For example, in order to realize seven kinds of gear ratios, it is necessary to prepare 49 kinds of conventional integrated gears, whereas in the case of this embodiment, the third gear 13 and the fourth gear 14 are provided. Need only be prepared for each of the seven types, and the required number of gears can be greatly reduced.

Further, since the third and fourth speed gears 13 are divided into a third speed gear 16 and a fourth speed gear 17, both gears 1 and 2 are separated.
6, 17 can be manufactured separately. Therefore, the problem of interference between the tool and the mating gear at the time of gear cutting of these gears can be solved, and the gear width can be reduced as required, and the size can be reduced.

Here, when the transmission gear is divided into two parts as in this embodiment and is integrated by locking the locking parts, the play between the locking parts hinders the shifting operation. It is feared that it will occur. However, in this embodiment, the third
The boss portion 16a is pushed by the shift fork 18 when moving to the speed gear 16 side, and the boss portion 17a is pushed by the shift fork 18 when moving to the fourth speed gear 17 side. An adverse effect on the shift operation due to the play can be avoided.

FIG. 4 shows a modification of the locking tooth portion in the above embodiment. In the drawing, the same reference numerals as those in FIG. 2 denote the same or corresponding parts. In this modification, the boss 17 of the fourth speed gear 17 is used.
The arc-shaped concave portions 27b are formed at predetermined pitches on the inner peripheral surface of a, and the arc-shaped convex portions 26b are formed on the outer peripheral surface of the boss portion 16a of the third speed gear 16 at the same pitch as described above. . The projection 26b is formed slightly smaller than the recess 27b so as to pass through the recess 27b.

[0022]

As described above, according to the transmission of the present invention, the transmission gear is divided into the first and second gears, and the two gears are mounted on the transmission shaft in an integrated state.
By appropriately combining the first and second gears, it is possible to cope with various speed ratios, and there is an effect that the number of gears to be prepared can be greatly reduced as compared with the conventional integrated speed gear. Therefore, the problem of interference does not occur, and therefore, the width of the gear can be reduced as required, and the size can be reduced. Furthermore, the first and second
After relatively moving the gears in the axial direction, it is possible to prevent the first and second gears from separating in the axial direction only by relatively rotating the gears,
Therefore, the structure is simpler and the number of parts and the number of assembling steps can be prevented from increasing.

[Brief description of the drawings]

FIG. 1 is a sectional plan view of a main part of a transmission according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional plan view of the transmission in the embodiment.

FIG. 4 is a cross-sectional front view showing a modification of the locking portion of the transmission of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission 2 Main shaft (transmission shaft) 13 Third / fourth gear (transmission gear) 16 Third gear (first gear) 16a Boss part 16b External locking teeth (first locking part) 17 Fourth speed Gear (second gear) 17a Boss part 17b Internal locking teeth (second locking part)

Claims (1)

(57) [Claims] 1. A transmission gear having a cylindrical shape and having first and second meshing teeth on an outer peripheral surface and a female serration on an inner peripheral surface is slidable in the axial direction by meshing with a male serration of a transmission shaft. And a transmission gear mounted to rotate with the transmission shaft and having a shift groove into which a shift fork is inserted between the first and second meshing teeth of the transmission gear. And a second gear having the second meshing teeth .
External gear teeth are formed on the outer peripheral surface of the first boss of one gear.
And the inner peripheral surface of the second boss portion of the second gear
A locking tooth is formed, and in a state where the first and second gears are disengaged from the transmission shaft, the outer locking teeth are aligned so that the respective teeth are located between the respective inner locking teeth. After relative movement to
The first and second gears are integrated by locking the outer and inner locking teeth so as to prevent relative movement in the axial direction by relative rotation about the axis, and the integrated first and second gears And a shift groove formed between the first and second boss portions.