JPS6322358Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a shift drum transmission for a motorcycle.

Generally, in the shift drum transmission, a plurality of lead grooves are provided on the outer circumferential surface of the shift drum, and a shifter for switching the shift gear of the transmission gear mechanism is engaged with these lead grooves, and when the gear change pedal is depressed,
Alternatively, the shift drum is rotated by a predetermined angle by depressing the pedal, and multiple shifters are selectively moved along with this rotation, and the meshing of the shift gears is changed to sequentially perform each stage of gear shifting. However, in such a shift drum transmission, only one set of stopper and cam plate is prepared to hold the shift drum in each gear shift position and the neutral device, and that only one cam plate is used for all gear shifts including the neutral stage. A stopper groove corresponding to the step is formed (see Japanese Patent Publication No. 44-9136).

However, when the conventional gears are multi-staged, the unit gear shift angle of the shift drum becomes smaller, and as a result, the neutral stopper groove, which has a particularly narrow groove width, cannot be sufficiently deep. There is a problem in that the stopper tends to slip against the groove, making it difficult to insert the neutral.

The present invention was proposed in view of the above, and aims to provide a shift drum transmission for a motorcycle with a simple structure capable of solving the above-mentioned problems of conventional ones. In a shift drum transmission for a motorcycle, the shift gear mechanism can be controlled to switch to all gears including a neutral gear using a shifter operated by the shift drum.
The stopper includes a first stopper for regulating a part of the rotation of the shift drum in one cycle, and a second stopper for regulating the remaining rotation, and the stopper is configured to actuate the first stopper. A first cam plate that operates the second stopper and a second cam plate that is coaxially arranged with the first cam plate and that operates the second stopper are integrally formed into a single speed change cam body, and the cam body is connected to the shift drum. The first cam plate is provided with a stopper groove capable of holding the shift drum at a plurality of operating positions corresponding to some gears of the transmission gear mechanism by engagement with a first stopper. Further, the second cam plate is provided with a stopper groove capable of holding the shift drum at the remaining operating position by engagement with a second stopper.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.A shift drum 1 of a drum transmission is rotatably mounted on a transmission case M of an internal combustion engine mounted on a motorcycle, and is adjacent to the transmission case M. The shifter guide shaft 2 is supported. A plurality of lead grooves 3 ₁ , 3 ₂ , 3 ₃ are formed on the outer periphery of the shift drum 1 at intervals in the longitudinal direction, and on the other hand, the shifter guide shaft 2 has the lead grooves 3 ₁ , 3 3 . 3 ₂ , 3 ₃ and the same number of shifters 4 ₁ , 4 ₂ , 4
guide pins _{5 1} , 5 ₂ , which are fitted in the shifters 4 ₁ , 4 ₂ , 4 ₃ so as to be slidable in the axial direction;
5 ₃ are respectively engaged with the lead grooves 3 ₁ , 3 ₂ , 3 ₃ so as to be relatively movable. Shifter 4 ₁ , 4 ₂ , 4 ₃
are the shift gears 6 ₁ , 6 ₂ , 6 ₃ in the transmission gear mechanism G provided in the transmission case M as usual.
As will be described in detail later, when the shift drum 1 is intermittently rotated by a predetermined shift angle, the shifters 4 ₁ , 4 ₂ , 4 ₃ are engaged with the lead grooves 3 ₁ , 3 ₂ , 3
₃ , the transmission gear mechanism G is selectively slidingly controlled by
Shift to multiple gears. In addition, shifters 4 ₁ , 4 ₂ ,
Since the speed change operation means of the speed change gear mechanism G according to _4.3 is conventionally known, detailed explanation will be omitted.

The shift drum 1 is configured for six-speed transmission, and a speed change cam body 7 is fixed to one end of the shift drum 1. This speed change cam body 7 has an annular groove 8 in between, and a first cam plate 9 on the outside thereof. , and a second cam plate 10 is integrally formed inside thereof, and both cam plates 9 and 10 are arranged coaxially with each other. The speed change cam body 7 has a 360° circumference as shown in Figure 3.
Divide by 5.5, each shift angle α from speed to speed is 65°30′, and the remaining angle β between speed (Top) and speed (Low) that is not used for the remaining speed changes is
Set 32°30′ (360°−65°30′×5).

The first cam plate 9 is formed in a star shape, and on its outer periphery, there are arcuate stopper grooves for the first to third speeds with the gear shift angle α (65°30′) shown in FIG.
. ′) is maintained.

The speed change cam body 7 includes first and second cam plates 9 and 10.
The first to fifth drum pins 11 ₁ , 11 ₂ ,
11 ₃ , 11 ₄ , and 11 ₅ are provided radially. The first to fifth drum pins 11 ₁ to 11 ₅ are all located at the top of the star-shaped first cam plates 9 and 10, and the first drum pin 11 ₁ is located near the auxiliary stopper groove'. Fifth drum pin 11 ₂ , 11 ₃ , 1
1 ₄ and 11 ₅ are intermediate between the stopper grooves, , and , respectively, and the angular interval from the first drum pin 11 ₁ to the fifth drum pin 11 ₅ is the shift angle α (65°30'). , fifth and first
There is a gear shift angle α (65°30') between drum pins ₁₁₅ and ₁₁₁ .
A larger angular interval is maintained than the sum of the remaining angle β (32°30′).

On the other hand, the second cam plate 10 is provided with the first to fifth drum pins 11 ₁ to 11 ₅ as shown in FIG. 4, and on the outer circumference between the first and second drum pins 11 ₁ and 11 ₂ , The stopper groove for the second speed is also
A neutral stopper groove N is formed on the outer periphery between the third drum pins 11 ₂ and 11 ₃ .

In the vicinity of the shift drum 1, first and second stoppers 17 and 18 are rotatably supported by the transmission case M with a support shaft 16, and the first stopper 17 is rotated by a first stopper spring 19. The second stopper 18 is urged to swing toward the second cam plate 10 by a second stopper spring 20. First and second stopper rollers 21 and 22 are rotatably supported at the tips of the first and second stoppers 17 and 18, respectively.
The second stopper roller 22 is sequentially engaged with the first speed stopper groove formed on the first cam plate 9 and the second speed auxiliary stopper groove formed on the second cam plate 10. The first speed and neutral stopper grooves and N are engaged with each other.

As shown in FIG. 1, a conventionally known shift drum rotation mechanism R is provided below the shift drum 1. As shown in FIG. That is, a change spindle 24 provided with a change pedal is rotatably supported on the transmission case M, and a change arm 25 is integrally fixed to the change spindle 24. At the tip of the change arm 25, a drum rotation arm 26 is rotatably supported by a support pin 27. A pair of claw pieces 28 and 29 are provided on the drum rotation arm 26 and project from each other, and a spring 30 stretched between the change arm 25 and the drum rotation arm 26 is connected to the claw pieces 28 and 29 of the drum rotation arm 26. 29
act to engage with the first to fifth drum pins 11 ₁ to 11 ₅ . Further, as is well known, the change arm 25 is provided with a return spring 31 and a stopper pin 32, and due to their cooperative action,
When no operating force is applied to the change spindle 24, the change arm 25 is held in the non-operating position shown in FIG.

Next, to explain the operation of the embodiment of the present invention, FIG. 3 shows that the shift drum 1 is at the top speed.
, the stopper roller 21 of the first stopper 17 is in the auxiliary stopper groove for the first speed of the first cam plate 9, and the second stopper 18 is in the stopper groove for the second speed of the second cam plate 10. The shift drum 1 is held in the first speed position by engagement. Then, as usual, from this state, shift drum 1
The lead grooves 3 ₁ , 3 ₂ , and 3 ₃ formed in the shift drum 1 prevent the shift drum 1 from rotating toward the low speed side, that is, in the counterclockwise direction in FIG. 3 . By the way, when the drum rotation arm 26 is moved one stroke leftward by rotation of the change spindle 24 by operating the speed change pedal from the state shown in FIGS. 3 and 5A, the engagement between the fifth drum pin ₁₁₅ and the pawl piece 28 is Accordingly, the shift drum 1 is rotated by a unit gear shift angle α, that is, 65°30′, and the first stopper 1 is rotated.
The first stopper roller 21 of 7 is engaged with the first speed stopper groove of the first cam plate 9 from the auxiliary stopper groove', while the second stopper roller 22 of the second stopper 18 is engaged with the second speed stopper groove of the second cam plate 10. It comes off the stopper groove and comes into contact with its outer circumferential surface, resulting in the first speed state shown in FIG. 5B. The rotation of the shift drum 1 causes the lead grooves 3 ₁ , 3 ₂ ,
The shifters 4 ₁ , 4 ₂ , and 4 ₃ engaged with the shifter 3 ₃ move on the shift guide shaft 2 to switch the speed change gear mechanism G to the state of the first gear.

Thereafter, if the drum rotating arm 26 is moved one stroke at a time to the left by operating the speed change pedal in the same manner, the claw pieces 28 will move from the 4th, 3rd, 2nd, and 1st drum pins 11 ₄ , 11 ₃ , 11 ₂ , and 11 ₁ , the shift drum 1 is intermittently rotated clockwise by a unit gear change angle α, that is, 65°30′, and the shift drum 1 is engaged with the shift drum 1 intermittently clockwise by a unit gear change angle α, that is, 65°30′, and shifts to the 1st, 2nd, 3rd, and 3rd gears as shown in FIG. A switch is made.

Therefore, when the sheet drum 1 is in the half-stroke stage when it changes from the first speed to the second speed (Low) as shown in FIG. 2 stopper roller 2
2 engages with the neutral stopper groove N to stop the shift drum 1 at the neutral position, and holds the transmission gear mechanism G at the neutral position via shifters 4 ₁ , 4 ₂ , and 4 ₃ .

When the shift drum 1 is rotated clockwise by one stroke, that is, by a unit shift angle α (65°30') as described above, the speed (Top), speed, speed, etc. , speed, speed, speed (Low) can be performed in 6 steps,
Further, at the half-stroke stage between speeds, the shift drum 1 is locked at the neutral position as shown in FIG. When the shift drum 1 is rotated to the low position, the shifters 4 ₁ , 4 ₂ , 4 ₃ reach one end of the lead grooves 3 ₁ , 3 ₂ , 3 ₃ formed on the outer periphery of the shift drum 1 . The shift drum 1 does not rotate clockwise in FIG. 3, that is, from speed to speed. As mentioned above, the remaining angle β of the shift drum 1 without rotation from speed to speed is 32°30'.

Furthermore, if the change spindle 24 is reversely swung from the low speed state shown in FIG. 5 by operating the speed change pedal in the opposite manner to that described above, the drum rotating arm 26 will move to the right in FIG. 3. Then, the other claw piece 29 sequentially engages with the drum pins 11 ₁ , 11 ₂ . . . and rotates the shift drum 1 counterclockwise one stroke at a time. It is possible to change gears from speed to speed. In this case as well, it is possible to lock the neutral position with the half stroke from speed to speed as shown in Figure 5, and the remaining angle β (32°30') from speed to speed.
It is now impossible to rotate.

By the way, the shift drum of a conventional drum transmission of this type is provided with drum pins at equal angles, and in the case of a six-speed transmission, for example, as shown in FIG. is provided, so the shift drum 01 rotates with a unit shift angle of 60 degrees between speeds (does not rotate between speeds), whereas in the case of the six-speed transmission in the above embodiment, As mentioned above, the shift drum 1 changes the shift angle per unit shift from speed to speed.
Since it rotates at an angle of 65°30', the lead grooves 3 ₁ , 3 ₂ , 3 ₃ formed on the outer peripheral surface of the shift drum 1
The distance per unit gear shift angle α can be lengthened, and the shifter 4 ₁ , of the lead grooves 3 ₁ , 3 ₂ , 3 ₃ can be lengthened.
The inclination angle of the inclined part for shifting 4 ₂ and 4 ₃ is
The lead grooves 3 ₁ , 3 _{2 ,} 3 3 are smoother than the conventional ones, making the shift operation light and smooth, and at the same time keeping the shifters 4 ₁ , 4 ₂ , _{4 3} still in their positions after shifting. The length of the straight portion of the shifters 4 ₁ , 4 ₂ , and 4 3 becomes stable, and the shift positions of the shifters 4 1 , 4 2 , and 4 ₃ become stable.

As described above, according to the present invention, the shift drum 1
A shift drum transmission for a motorcycle, in which the rotation of the shift drum is regulated by a stopper, and a transmission gear mechanism G can be controlled to switch to all gears including a neutral gear using shifters 4 ₁ to 4 ₃ operated by the shift drum 1. In the machine, the stopper is composed of a first stopper 17 for regulating a part of the rotation of the shift drum 1 in one cycle, and a second stopper 18 for regulating the remaining rotation, A first cam plate 9 that operates the first stopper 17 and a second cam plate 10 that is coaxially arranged with the first cam plate 9 and operates the second stopper 18 are integrated into a single speed change cam body 7. In addition, the cam body 7 is provided so as to be able to rotate integrally with the shift drum 1, and the first cam plate 9 is provided with the shift drum 1 by engagement with a first stopper 17. The second cam plate 10 has a stopper groove that can hold the shift drum 1 at a plurality of operating positions corresponding to some gears, and the shift drum 1 can be held at the remaining operating positions by engagement with a second stopper 18. Since the stopper grooves N for holding the shift drum 1 are provided, the depth of the neutral stopper groove N for holding the shift drum 1 in the neutral position is
It is now possible to set the unit gear shift angle of the shift drum 1 relatively freely without being influenced by the magnitude thereof, and therefore, the unit gear shift angle of the shift drum 1 becomes smaller as the number of gear stages of the gear transmission mechanism G increases. However, since the depth of the neutral stopper groove N can be ensured sufficiently, even when performing a so-called half-stroke operation on the shift drum 1, the corresponding stopper 18 can always be accurately placed in the neutral stopper groove N. As a result, even if the number of gears is increased, there is no risk of problems such as difficulty in shifting to neutral. Moreover, although the cam plates 9 and 10 are provided as a pair corresponding to the first and second stoppers 17 and 18, they are formed together in one speed change cam body 7.
This does not cause an increase in the number of parts and can contribute to cost reduction.

[Brief explanation of the drawing]

1 to 5 show one embodiment of the present invention,
Fig. 1 is a side view thereof, Fig. 2 is a developed cross-sectional view thereof, Fig. 3 is an end view of the first cam plate, and Fig. 4 is a
An end view of the second cam plate, FIGS. 5A to 5D are views showing the operating state of the present invention, and FIG. 6 is an end view of a conventional shift drum. G... Speed gear mechanism, 1... Shift drum, 7
...Speed cam body, 9...First cam plate, 10...Second cam plate, 17...First stopper, 18...Second
Stopper, ~...Stopper groove for shifting, N...
Stopper groove for neutral.

Claims (1)

[Scope of utility model registration request] The rotation of the shift drum 1 is regulated by a stopper, and the shifter ₄₁ to ₄₃ operated by the shift drum 1 can control the transmission gear mechanism G to switch to all gears including the neutral gear.
In a shift drum transmission for a motorcycle, the stoppers include a first stopper 17 for regulating a part of the rotation of the shift drum 1 in one cycle, and a second stopper for regulating the remaining rotation. 18, and the first stopper 17
A first cam plate 9 that operates the first cam plate 9 and a second cam plate 10 that is coaxially arranged with the first cam plate 9 and that operates the second stopper 18 are integrally formed in a single speed change cam body 7, The cam body 7 is provided so as to be able to rotate integrally with the shift drum 1, and the first cam plate 9 has a cam body 7 which, when engaged with a first stopper 17, moves the shift drum 1 to a part of the gear stage of the transmission gear mechanism G. The second cam plate 10 has a stopper groove that can be held in a plurality of operating positions corresponding to the second cam plate 10.
The shift drum 1 due to engagement with the stopper 18
a stopper groove N capable of retaining the remaining operating position;
A shift drum transmission for a motorcycle, characterized in that each of the following is provided.