JPH02134437A - Synchromesh transmission - Google Patents

Abstract

PURPOSE:To abate the extent of knocking noises at time of idling as well as to perform the synchronization of a synchromesh mechanism so smoothly by setting up a direct-coupled synchromesh mechanism in place more rearward than other synchromesn mechanisms, while these other ones on an input shaft, and installing a reduction gear in the rear end of a countershaft. CONSTITUTION:At time of idling, respective synchromesh mechanisms 12, 14 and 17 are situated in each neutral position, so that an output shaft 5 and a countershaft 6 are stopped each, and thereby a third gear 10 and a fourth gear 11 set up on an input shaft 4 are also stopped. A first gear 15 and a second gear 16 are raced, but since the number of racing gears is few, a knocking noise is little as well. Reduction gears 13, 21 are not interposed between the input shaft 4 and the countershaft 6, so that any influence of each gear ratio of these reduction gears 13, 21 is not exerted on these synchromesh mechanisms 12, 14 and 17 at all. Thus, the reduction gears 13, 21 are installed in space between a rear end of the countershaft 6 and the output shaft 5, whereby driving torque of the input shaft 4 is transmitted to each of speed change gears 7, 9, 10, 11, 15, 16, 19 and 20 without being amplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gear transmission, particularly a manual transmission suitable for FR vehicles.

[Conventional technology]

Conventionally, there is a structure of a manual transmission for an FR vehicle as shown in FIG. 2. This transmission has 4 forward gears and 1 reverse gear, and the engine output shaft 3
An input shaft 32 and an output shaft 33, which are connected to each other via a clutch 31, are arranged adjacent to each other on the same axis, and a counter shaft 34 is arranged parallel to these shafts. A reduction gear 35 provided at the rear end of the input shaft 32 meshes with a reduction gear 36 integrally formed at the front end of the countershaft 34, and constantly drives the countershaft 34. On the output shaft 33 is a third speed gear 37. 2nd speed gear 38. A first speed gear 39 is rotatably supported. A synchromesh mechanism 40 is provided between the rear end of the input shaft 32 and the front end of the output shaft 33 for switching between the direct gear (4th gear) and the 3rd gear. A synchromesh mechanism 41 is provided for switching between first speed and second speed. The countershaft 34 also has the third speed gear 37. 2nd speed gear 38. Gears 42 meshing with the first speed gear 39,
43 and 44 are each integrally formed. Above 1st-
A reverse gear 45a is formed on the sleeve 45 of the two-speed synchronized mesh mechanism 41, and this gear 45a meshes with a reverse gear 46 formed on the countershaft 34 via an idle gear 47.

With the above configuration, the synchromesh mechanism 40.41 switches between a direct gear stage in which the output shaft 33 is directly driven by the input shaft 32 and a plurality of gear stages in which the output shaft 33 is driven via the counter shaft 34. It is possible.

[Problem to be solved by the invention]

However, in the case of the gear transmission with the above structure, all the transmission gears 37, 38, and 39 idle through the countershaft 34 during idling, so many gears idle, resulting in "rattle noise" caused by fluctuations in engine rotation. There is a problem in that the rattling sound called `` becomes louder. Furthermore, since the countershaft 34 is driven with torque amplified by the reduction gears 35 and 36, and the torque is further amplified by the gear ratio of each transmission gear train, the inertial weight acting on the synchromesh mechanism 40, 41 is equal to the clutch weight. Reduction gear 35.36
The value is approximately proportional to the product of the gear ratio of and the gear ratio of each transmission gear 37, 38, 39. In other words, there is a problem in that the inertial weight acting on the synchromesh mechanism 40.41 is large, reducing the synchronization performance of the synchromesh mechanism 40.41. Furthermore, since the drive torque of the input shaft 32 is amplified by the reduction gears 35, 36 and transmitted to the counter shaft 34 as described above, the load on each transmission gear 37, 38, 39 and 42, 43, 44 increases. Therefore, it is necessary to increase the width dimension of each gear, which results in an increase in the axial dimension of the transmission.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a gear transmission that can reduce rattling noise during idling, smoothly synchronize the synchromesh mechanism, and shorten the width of the transmission gear. .

[Means to solve the problem]

In order to achieve the above object, the present invention arranges a synchronized mesh mechanism of a directly connected stage at the rear of other synchronized mesh mechanisms, and also places all or part of the other synchronized mesh mechanisms on the implant shaft. The invention is characterized in that a reduction gear for transmitting power from the countershaft to the output shaft is provided at the rear end of the countershaft.

(Function) That is, all or part of the synchromesh mechanism other than the direct connection is provided on the input shaft, and the reduction gear is placed between the countershaft and the output shaft, so that the countershaft does not idle during idle linking. All of the transmission gears either stop or only some of them idle, so the "rattle noise" that accompanies engine rotational fluctuations can be significantly reduced.

In addition, since there is no reduction gear interposed between the countershaft and the impulse shaft, the synchromesh mechanism is not affected by the gear ratio of the reduction gear, and the inertial weight is small. Synchronization by the mechanism can be performed extremely smoothly and quickly.

Furthermore, since the reduction gear is provided between the rear end of the countershaft and the output shaft, the drive torque of the input shaft is transmitted to each transmission gear without being amplified, and the load on each transmission gear is reduced. becomes smaller. Therefore, the width dimension of the gear can be reduced, and the axial dimension of the transmission can be reduced.

[Embodiment] Fig. 1 shows an example of a gear transmission according to the present invention applied to an FR type heavy vehicle. This transmission has 5 forward speeds.

It has one reverse gear, and the fifth gear is directly connected.

A flywheel 2 is fixed to an end of an engine output shaft 1, and the flywheel 2 is connected to an input shaft 4 via a clutch 3. Output shaft 5
are arranged adjacent to and on the same axis as the input shaft 4, and a countershaft 6 is arranged parallel to these shafts 4.5.

A first gear 7, a reverse gear 8, and a second gear 9 are integrally formed in the center of the input shaft 4. Further, a third speed gear 10 is disposed on the rear end of the input shaft 4.
and a fourth speed gear 11 are rotatably supported, and a synchronized mesh machine for switching between 3 and 4 speeds selectively connects these gears 10 and 11 to the input shaft 4.
12 are provided.

A reduction gear 13 is integrally formed at the front end of the output shaft 5, and a synchromesh system for direct coupling (fifth speed) switching is provided between the input shaft 4 and output shaft 5 to selectively connect both shafts. A mechanism 14 is provided. The rear end of the output shaft 5 is connected to wheels via a transmission mechanism (not shown) such as a drive shaft.

At the front end of the countershaft 6, a speed change gear 15.16 that meshes with the first speed gear 7 and the second speed gear 9, respectively, is rotatably supported. A synchromesh mechanism 17 for selectively connecting the first and second speeds is provided. Note that a reverse gear 18a is integrally formed on the sleeve 18 of this synchromesh mechanism 17, and this gear 18
a can mesh with the reverse gear 8 of the implant shaft 4 via an idle gear (not shown). Further, at the rear end of the countershaft 6, transmission gears 19 and 20 that mesh with the third gear gear 10 and the fourth gear 11, respectively, are integrally formed. A reduction gear 21 that meshes with the reduction gear 13 of the output shaft 5 is integrally formed.

Note that this reduction gear 13.21 is formed slightly wider than the other gears.

Next, the operation of the gear transmission having the above configuration will be explained.

First, when idling, each synchronized mesh mechanism 12
．． 14.17 is in the neutral position, the output shaft 5 and the countershaft 6 are at rest, and the third speed gear 10.17 arranged on the input shaft 4. The fourth speed gear 11 is also stopped. Although the first speed gear 15 and the second speed gear 16 arranged on the countershaft 6 idle, the number of idle gears is small, so the rattling noise caused by engine rotational fluctuations is less than before. Therefore, less space is required to take measures to eliminate rattling noise (such as a sub-gear system or a sliding resistance system).

Further, since the reduction gear 13.21 is provided between the counter shaft 6 and the output shaft 5, and no reduction gear is interposed between the input shaft 4 and the counter shaft 6, the synchromesh mechanism 12.14.17
is not affected by the gear ratio of the reduction gear 13.21. In other words, the inertia weight acting on the synchromesh mechanism 12, 14, 17 is approximately equal to the value obtained by multiplying the inertia weight of the clutch 3 by the gear ratio of each transmission gear train, so the reduction gear 13.
The inertia weight is reduced by 21 gears, and the synchronization performance can be improved.

Furthermore, by providing a reduction gear 13.21 between the rear end of the countershaft 6 and the output shaft 5, each transmission gear 7. 9.10.11, 15, 16.
At 19.20, the driving torque of the input shaft 4 is transmitted without being amplified. Therefore, the load on each transmission gear is reduced, and the width dimension of each gear can be reduced.
The axial dimension of the transmission can be shortened. That is, although the tooth width of the reduction gears 13, 21 is larger than that of the conventional gear, the tooth widths of the plurality of speed change gears can be shortened, so that the axial dimension of the transmission as a whole can be shortened.

In the above embodiment, the first and second speed synchromesh m
Although the synchronizer mechanism 17 is provided on the counter shaft 6, the synchronizer mechanism 17 may also be provided on the input shaft 4. In this case, there is no need for a speed change gear that idles during idling, reducing rattle noise and improving synchronization performance. This is even more advantageous. In addition, if the +J hearth gear is integrally formed with the sleeve of the synchromesh mechanism, it is difficult to install the reverse gear on the input shaft 4.
The reverse gear may be provided at a different location.

Further, in the above embodiment, a transmission with five forward speeds (the fifth speed is directly connected) and one reverse speed has been described, but it goes without saying that the present invention can also be applied to a transmission with other gear stages.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the synchromesh mechanism of the direct-coupled stage is disposed at the rear of the other synchromesh mechanisms, and all or part of the other synchromesh mechanisms are placed on the input shaft. Since a reduction gear for transmitting power from the countershaft to the output shaft is provided at the rear end of the countershaft, fewer gears rotate idly during idling, and gear rattling noise can be reduced. In addition, since the inertial weight acting on the synchro mesh mechanism is small, the synchronization performance of the synchro mesh mechanism can be improved, and the front edge of each transmission gear is also reduced, so the tooth width of the transmission gear can be shortened, making the transmission more compact. can be converted into

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an example of a gear transmission according to the present invention, and FIG. 2 is a schematic configuration diagram of a conventional example. 4... Input shaft, 5... Output shaft, 6... Counter shaft, 7.15... First speed gear, 8, 18a... Reverse gear, 9.16...
・Second speed gear, 10.19...Third speed gear, 11.2
0... Fourth speed gear, 12, 14.17... Synchromesh mechanism, 13.21... Reduction gear. Patent applicant Daihatsu Motor Co., Ltd. Representative Patent attorney Hidetaka Tsutsui

Claims (1)

[Claims] An input shaft and an output shaft are arranged adjacent to each other on the same axis, and a counter shaft is arranged parallel to these shafts, and a direct coupling stage in which the output shaft is directly driven by the input shaft, and a counter shaft is arranged in parallel with the output shaft. In a gear transmission equipped with a synchromesh mechanism that can switch between multiple gears that drive the output shaft through the A gear transmission characterized in that all or part of the mechanism is provided on an input shaft, and a reduction gear for transmitting power from the countershaft to the output shaft is provided at the rear end of the countershaft.