SU510404A1 - Gear shift mechanism - Google Patents

Description

one

FIELD: transport engineering.

Gear shift mechanisms are known, primarily for motorcycle gearboxes, which include a pedal-driven shift shaft, a carrying crank and double-acting spring for setting the crank to its original position, associated with the crank ratchet device with a pawl, having cavities and bevels that interact with the pins of the disc cam mounted on the axle fixed in the gearbox housing.

Such gear shifting mechanisms are complex and inoperative without an additional device.

The large dimensions of the mechanisms influence the dimensions of the gearbox during line-up, which impairs motorcycle parameters, for example, it reduces ground clearance or increases the center of gravity.

In addition, the connection of the crank with the shift drum is not directly, but through the dog loosely mounted on the crank reduces the shift clarity.

In order to increase the reliability of gear shifting on the crank and dog, the lugs are made in the holes of which an axis is installed, while the lugs of the dog are placed between the ears of the crank and provided with stops interacting with the crank.

FIG. 1 shows the proposed mechanism, side view; in fig. 2 is a section along A-A, top view (a variant with a hollow roller of a foot pedal on a kick starter shaft); in fig. 3 - dog cam profile; in fig. 4 - section along BB (fastening of the dog on the crank). In the proposed mechanism, the crank 1 is rigidly fixed on the shift shaft 2. Spring loaded dog 3 is equipped with ears

4 and stops 5, located on the ears, and mounted on crank 1, on which ears 6 are made. Ears 4 dogs 3 and ears 6 of crank 1 are aligned and axle 7 is inserted in their holes, locked by ring 8.

The stops 5 of the pawl 3 by means of the spring 9 interact with the crank 1.

The mechanism also contains a stop 10, limiting the stroke of the crank 1, the cams 11, made on the dog 3, the drum 12. shifting and pins 13.

The gearshift works as follows.

In the process of gear shifting, crank 1 with dog 3 makes an angular movement with shaft 2 from the movement of the foot pedal (not shown in Fig.). In this case, the dog is pressed by one of the cams 11, depending on the movement of the crank up or down, to the pin 13 of the switching drum 12,

forced the latter to make the necessary angular displacement until the end of the stroke of the crank, limited by the stop 10. When the force is removed from the foot, the mechanism, as usual, takes its initial position due to the spring 9 of double action. When the crank returns to its initial position, the pawl, passing by the pins 13, deviates away from the pins with the help of the rounded surfaces of cams II, and then takes the original position under the action of the spring 9.

Invention Formula

A gearshift mechanism, primarily for motorcycle gearboxes.

containing a pedal-driven switching shaft, carrying a crank and equipped with a double-acting spring for setting the crank to its initial position, connected with the crank 5 ratchet device with a pawl, having depressions and bevels that interact with the cam-cam pins mounted on the axis fixed in the crankcase gears, characterized in that, in order to increase the reliability of gearshifts, on the crank and dog, there are lugs in which holes an axis is installed, while the lugs of the dog are placed between the ears Amy-curve and equipped with lugs, interacting with the crank.

12 3, 3 ff

13

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