JPH0520912Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a device for preventing backlash in the thrust direction (axial direction) of the countershaft of a manual transmission.

(Prior Art) Due to variations in component tolerances, manual transmissions are inevitably subject to axial thrust backlash between the countershaft and the transmission case that supports the countershaft during assembly. Conventionally, this thrust play was normally adjusted by inserting shims of appropriate thickness into the gaps that caused it during assembly (January 1971, published by Nissan Motor Co., Ltd., "Datsuto Sun Truck 620
(The part described on page 102 of ``Model 1972 Maintenance Manual'').

(Problem that the invention seeks to solve) However, such shim adjustment significantly deteriorates the ease of assembling the manual transmission, and the reality is that even with this shim adjustment, the thrust play of the countershaft cannot be eliminated. Ta. Furthermore, even if the shim adjustment is successful, if the shim wears down and changes in thickness due to long-term use of a manual transmission, the countershaft will generate thrust play, so it is important to maintain a state without thrust play for a long time. I couldn't do it.

Thrust play in the countershaft causes the countershaft to move in the axial direction with respect to the transmission case due to vibrations, etc., and noise is generated due to interference between gears provided on the countershaft and gears that mesh with these gears.

(Means for solving the problem) By the way, the countershaft is provided with a sub-gear that is juxtaposed to the counter-drive gear provided thereon via a sub-gear bracket, and the sub-gear also meshes with the main drive gear that meshes with the counter-drive gear. There is a technique for eliminating backlash between the counter drive gear and the main drive gear by pressing the sub gear against the counter drive gear using an elastic body seated on the sub gear bracket.

The present invention solves the above-mentioned problems all at once in a manual transmission using this non-buckling technology by urging the countershaft in the axial direction using the elastic body and sub-gear bracket. It is something.

(Function) By using the sub-gear bracket as a reaction force receiver and urging the countershaft in the axial direction by the elastic body, the countershaft is elastically supported at the limit position in the same direction with respect to the transmission case, and thrust backlash is prevented.

Since the thrust play of the countershaft is eliminated by using the existing elastic body, there is no need for any new parts, no complication of the structure, and no deterioration of assembly workability. Moreover, the above-mentioned bullet support can reliably eliminate thrust backlash of the countershaft, and can maintain this state free of thrust play over the entire service life of the manual transmission.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

The drawing shows a manual transmission for a vehicle equipped with a thrust rattling prevention device according to an embodiment of the present invention, in which 1 is a transmission case, 2 is a main drive shaft, 3 is a countershaft, and 4 is a main shaft. The transmission 1 is composed of a case body 1a, a front cover 1b, and an adapter plate 1c, and a main drive shaft 2 is rotatably supported by the case body 1a via a ball bearing 5. The left end of the main drive shaft 2 in the figure protrudes through the front cover 1b, and is drivingly coupled to an engine (not shown) via a clutch (not shown), and a main drive gear 6 is integrally formed at the right end of the main drive shaft 2 in the figure. do.

If the countershaft 3 needs to support a large radial load, it is better to receive the radial load and thrust load with separate bearings, and for the radial load, both ends of the shaft are connected to the case using roller bearings 7 and 8. It is rotatably supported on the main body 1a and the adapter plate 1c, and a counter drive gear 9, a third
The speed counter gear 10, the second speed counter gear 11, and the first speed counter gear 12 are integrally molded. The counter drive gear 9 is meshed with the main drive gear 6, and the gears 10 to 12 are meshed with the third speed main gear 13, the second speed main gear 14, and the first speed main gear 15, respectively.
are rotatably provided on the main shaft 4, respectively.
The main shaft 4 is disposed coaxially facing the main drive shaft 2, and the left end in the figure is connected to the main drive shaft 2 by a needle bearing 16, and the right end in the figure is connected to a ball bearing 17.
is rotatably supported on the adapter plate 1c.

Reference numeral 18 denotes a synchronized mesh mechanism, which drives and connects the third speed main gear 13 to the main shaft 4 when the coupling sleeve 19 is moved to the right in the figure from the neutral position shown in the figure via the shift fork 21 by the fork rod 20. 19
Conversely, when the main shaft 4 is moved to the left in the figure, the main shaft 4 is directly connected to the main drive shaft 2. The second speed main gear 14 and the first speed main gear 15 can also be connected to the main shaft 4 as appropriate by other similar fork rods, shift forks, and synchronized mesh mechanisms (not shown).

The thrust force applied to the countershaft 3 is transmitted by the thrust bearing 22 as a thrust member,
A sub-gear bracket 24 is inserted between the thrust bearing 22 and the counter drive gear 9, and this sub-gear bracket is drivingly connected to the counter shaft 3 by a drive ball 25.
4a allows movement on the countershaft 3 in the axial direction. A sub gear 26 is arranged on the side of the counter drive gear 9 near the thrust bearing 22, rotatably mounted on the bracket 24, and meshed with the main drive gear 6. A flange 24b is integrally formed on the outer periphery of the sub-gear bracket 24, and a disc spring 27 as an elastic body is compressed between the flange 24b and the sub-gear 26. Thus, the disc spring 27 presses the sub gear 26 against the counter drive gear 9, and the reaction force urges the sub gear bracket 24 in the direction away from the counter drive gear 9, but the sub gear bracket 24 does not come off in the same direction. Stopping is performed by a snap spring 28 attached to the countershaft 4.

The operation of the above embodiment will be explained next. Engine power input to the main drive shaft 2 is transmitted to the counter shaft 8 via the main drive gear 6 and the counter drive gear 9. Here, when the first speed main gear 15 is drivingly connected to the main shaft 4, the deceleration power at the first speed gear ratio is output from the main shaft 4, and when the second speed main gear 14 is drivingly connected to the main shaft 4, the main shaft 4 outputs deceleration power at the first speed gear ratio. 4 outputs the deceleration power at the second speed gear ratio, and when the third speed main gear 13 is drivingly connected to the main shaft 4, the main shaft 4 outputs the deceleration power at the second speed gear ratio.
The deceleration power at the high gear ratio is output. When the main shaft 4 is directly connected to the main drive shaft 2, the engine power is directly outputted from the main shaft 4 without being decelerated, and the fourth speed can be obtained.

By the way, the sub gear 26 is pressed against the counter drive gear 9 by the spring force of the disc spring 27, and a frictional force is generated between the sub gear 26 and the counter drive gear, and the reaction force of the disc spring 27 is applied to the sub gear bracket 24.
It reaches the thrust bearing 22 via. In this way, the sub gear 26 is dragged by the thrust bearing 22 and rotates relative to the counter drive gear 9 in the lag side in its rotational direction, thereby eliminating backlash between the main drive gear 6 and the counter drive gear 9, and reducing the meshing portion between these gears. This can further prevent the occurrence of rattling sounds.

On the other hand, the disk spring 27 constantly urges the countershaft 3 in the axial direction to the right in the figure via the sub gear 26 and the counter drive gear 9, since the sub gear bracket 24 is restricted in the left direction in the figure by the needle bearing 22. Therefore, it is possible to eliminate axial thrust backlash between the countershaft 3 and the transmission case 1 due to variations in component tolerances.

(Effects of the invention) As described above, the device of the present invention replaces the existing elastic body 27 (a disc spring in the illustrated example) which is essential for a non-bumping structure for eliminating bumps between the main drive gear 6 and the counter drive gear 9. Since the structure is configured to prevent thrust play of the countershaft 3 by using the sub gear bracket 24, there is no need for any new parts, no complication of the structure, and unlike the conventional method using shims. , does not deteriorate assembly workability. Furthermore, the elastic body 27 can reliably prevent the thrust backlash of the countershaft 3 from varying depending on the manual transmission, and can also prevent the axial bias of the countershaft 3 even if the manual transmission is worn out over time. Since this can be continued, a state without thrust backlash can be maintained throughout the service life of the manual transmission.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional side view of a main part of a manual transmission for a vehicle equipped with a thrust backlash prevention device according to an example of the present invention. 1... Transmission case, 2... Main drive shaft, 3... Counter shaft, 4... Main shaft, 6... Main drive gear, 7, 8...
...Roller bearing, 9...Counter drive gear, 10-12...Counter gear, 13-15...
...Main gear, 22, 23...Thrust bearing, 24...Sub gear bracket, 24a...Ball groove, 24b...Outer flange, 25...Drive ball, 26...Sub gear, 27...Dish spring (elastic body) , 28...Snat Spring.

Claims (1)

[Claims for Utility Model Registration] A countershaft is provided that is rotated by a main drive gear via a counter drive gear that meshes with the main drive gear, and a sub-gear that meshes with the main drive gear together with the counter drive gear is juxtaposed to the counter drive gear, The sub gear is rotatably supported on a sub gear bracket fitted to the counter shaft so as to rotate together with the counter shaft, and the main drive gear is pressed against the counter drive gear by an elastic body seated on the sub gear bracket. and a manual transmission designed to eliminate backlash between the counter drive gears, wherein the sub gear bracket is mounted so as to be displaceable in the axial direction with respect to the counter shaft, and the surface of the sub gear bracket that is far from the counter drive gear is connected to the transmission case. A thrust backlash prevention device for a countershaft for a manual transmission, which consists of a thrust bearing sandwiched between the shaft and the shaft.