JPH0733859B2 - Transmission with auxiliary transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission with an auxiliary transmission, that is, a vehicle transmission having a gear ratio larger than a normally used gear ratio.

[Conventional technology]

Conventionally, it is called an emergency low when a large driving force is required such as when a truck or the like starts up a hill on a hill or when a four-wheel drive vehicle escapes a swamp. A larger auxiliary gear ratio than the first gear is used.

As an example, as described in Japanese Utility Model Laid-Open No. 63-202522, an auxiliary transmission is provided between the output shaft of the transmission and a 2 / 4-wheel switching mechanism for switching between two-wheel drive and four-wheel drive. There is something. In this case, the auxiliary transmission has a first gear rotatably supported on the output shaft of the transmission, a second gear integrally provided on the output shaft of the auxiliary transmission, and a first output shaft. A switching sleeve that is selectively connected to a gear or a second gear and a parallel shaft that includes two gears that mesh with the first gear and the second gear. The switching sleeve is slid in the axial direction. As a result, the low speed ratio for transmitting the power of the output shaft of the transmission to the output shaft of the auxiliary transmission via the first gear, the parallel shaft and the second gear, and the power of the output shaft to the output shaft of the auxiliary transmission as they are. The high speed ratio to be transmitted is switched.

[Problems to be Solved by the Invention]

However, in the case of the above-described auxiliary transmission, the power of the output shaft must be transmitted to the output shaft of the auxiliary transmission through the parallel shafts in order to obtain the auxiliary low speed ratio. However, there is a problem that the number of parts is large and the weight is increased. In addition, in order to prevent interference between the bearing supporting the auxiliary shaft of the transmission and the bearing supporting the parallel shaft of the auxiliary transmission, the bearing supporting the parallel shaft is displaced in the radial direction from the bearing of the auxiliary shaft. There is no choice but to arrange them, and there is a problem that the auxiliary transmission becomes large.

As a means to solve such a problem, Jitsuko Sho 54-44135
There is known a transmission with an auxiliary transmission in which an intermediate shaft is coaxially arranged between an input shaft and an output shaft, and an auxiliary shaft is arranged in parallel with these shafts, as disclosed in Japanese Patent Laid-Open Publication No. 2003-242242. The counter shaft is extended forward,
A pair of gears for auxiliary shifting is provided between the input shaft and the front end of the counter shaft. A speed change gear pair is provided between the rear portion of the counter shaft and the output shaft.

In the case of this transmission with an auxiliary transmission, only one pair of gears is required for the auxiliary transmission, which is advantageous in that the number of parts can be reduced and the weight can be reduced.

However, since the auxiliary transmission is arranged on the input side of the transmission, the input torque is increased by the auxiliary transmission, and this increased torque acts on the transmission gear pair and the synchronizing device. Therefore, strength of the speed change gear pair is required, and there is a drawback that the gear becomes large. Further, although a load proportional to the square of the gear ratio is applied to the synchronizer, if the auxiliary transmission is arranged on the input side as described above, the load of the synchronizer also increases and there is a drawback that the shift performance is deteriorated.

Therefore, it is an object of the present invention to provide a transmission having a small number of parts, a small weight, and a small auxiliary transmission.

Another object is to provide a transmission with an auxiliary transmission that does not increase the load on the gears and the synchronizer.

[Means for Solving the Problems]

In order to achieve the above object, the present invention has an input shaft driven by an engine, an intermediate shaft coaxially arranged on the rear side of the input shaft, and an intermediate shaft coaxially arranged on the rear side of the intermediate shaft. An output shaft and a counter shaft arranged parallel to these shafts,
A pair of speed change gears forming a predetermined speed stage is provided between the input shaft and the front portion of the counter shaft, and a synchronizer for selectively driving the speed change gear pairs to realize one speed ratio is provided. The first gear is fixed to the rear part of the counter shaft, the second gear that meshes with the first gear of the counter shaft is fixed to the intermediate shaft, and both shafts are directly connected between the input shaft and the intermediate shaft. Is provided with a switching device for switching between a non-directly-connected stage and a non-directly-connected stage, and a third gear for auxiliary speed change is fixed on a counter shaft behind the first gear, and a fourth gear that meshes with the third gear is rotated on the output shaft. A high-low speed switching device, which is freely supported, is provided between the intermediate shaft and the output shaft to switch between a direct connection stage that directly connects both shafts and an auxiliary shift stage that connects the output shaft and the fourth gear. is there.

[Action]

The transmission of the present invention is different from the conventional method in which power is transmitted from the input shaft to the auxiliary shaft via the reduction gear pair, and further to the output shaft via the transmission gear pair. Is transmitted to the counter shaft, and power is further transmitted from the counter shaft to the intermediate shaft via the first gear. Therefore, the countershaft will rotate at the selected gear ratio rather than at a constant speed.

Therefore, the counter shaft is extended rearward and a third gear for auxiliary speed change is provided in the extension, and the third gear is meshed with the fourth gear on the output shaft, and the intermediate shaft and the output shaft are connected by the height switching device. If it is directly connected to or the output shaft and the fourth gear are connected to each other, it is not necessary to provide two pairs of gears as an auxiliary transmission unlike the conventional case, and only one pair of gears is required. Therefore, reduction of the number of gears can achieve weight reduction. Further, since the auxiliary shaft and the extension are coaxially located, it is not necessary to support the auxiliary shaft and the parallel shaft by separate bearings as in the conventional case, and the auxiliary transmission can be downsized. In particular, since the low speed ratio of the auxiliary transmission can be established at the same time as the speed ratio of the transmission, it is possible to obtain the number of speed stages twice the number of speed stages of the transmission.

Further, since the auxiliary transmission is arranged on the output side of the transmission, the torque increased by the auxiliary transmission does not act on the transmission gear pair and the synchronizing device, and the load does not increase. Therefore, there is no fear that the gears will become large and the shift performance of the synchronizer will not deteriorate. That is, it is possible to share the parts with a transmission that does not have an auxiliary transmission.

〔Example〕

FIG. 1 and FIG. 2 show an example in which the present invention is applied to a four-wheel drive transmission having five forward speeds and one reverse speed.
The speed is a direct connection stage and the fifth speed is overdrive. This transmission generally includes a transmission main body A, an auxiliary transmission B, and
It is composed of a 2 / 4-wheel switching device C.

The engine output shaft is the input shaft 1 via a clutch (not shown).
Is connected to the front end of the. The input shaft 1, the intermediate shaft 2, and the output shaft 23 are arranged coaxially with each other, and the sub shaft 3 is arranged in parallel with the shafts 1, 2, 23.

A first speed gear 4, a reverse gear 5, and a second speed gear 6 are integrally formed in the center of the input shaft 1. A fifth speed gear 7 is rotatably supported on the input shaft 1 adjacent to the right side of the second speed gear 6, and the fifth speed gear 7 is supported by the input shaft 1
There is provided a fifth-speed switching synchronizer 8 which is selectively connected to. A third speed gear 9 is rotatably supported on the right side of the fifth speed switching synchronizer 8.
A second gear 10 is integrally formed at the front end of the intermediate shaft 2 facing the. Further, between the third speed gear 9 and the intermediate shaft 2, there is provided a 3-4 speed switching synchronizing device 11 for selectively connecting the input shaft 1 to the third speed gear 9 or the intermediate shaft 2. . The rear end portion of the input shaft 1 is inserted into the recess of the intermediate shaft 2 and is rotatably supported by the needle bearing 12.

At the front end of the countershaft 3, speed change gears 13 and 14 that mesh with the first speed gear 4 and the second speed gear 6 are rotatably supported. There is provided a 1-2 speed switching synchronizer 15 which is selectively connected. A reversing gear 16a is integrally formed on the sleeve 16 of the synchronizer 15, and the gear 16a is an idler gear 17a.
It is possible to mesh with the reverse gear 5 formed integrally with the input shaft 1 via the. Further, transmission gears 18, 19 that mesh with the fifth speed gear 7 and the third speed gear 9, respectively, are integrally formed in the central portion of the sub shaft 3, and the rear portion of the sub shaft 3 is provided with the intermediate shaft 2 of the intermediate shaft 2. A first gear 20 that is constantly meshed with the second gear 10 is integrally formed.

A flange 22 integrally formed with the high speed side clutch teeth 22a of the high / low speed switching device 21 is spline-fitted in the center of the intermediate shaft 2, and the rear end of the intermediate shaft 2 is located in the recess of the output shaft 23. And is rotatably supported by a needle bearing 24. On the output shaft 23, the low speed side clutch teeth
A fourth gear 25 integrally formed with 25a is rotatably supported, and a switching sleeve 26 of the high / low speed switching device 21 connects one of the high speed side clutch teeth 22a and the low speed side clutch teeth 25a to the output shaft 23. To do. The auxiliary shaft 3 of the transmission is extended to a portion corresponding to the high / low speed switching device 21, and a third gear 27 meshing with the fourth gear 25 is integrally spline-fitted on the extension 3a. ing. The speed reduction ratio of the gear pair 25, 27 is higher than that of the transmission gear pair 10, 20.

The rear end of the output shaft 23 is connected to the rear wheel via a transmission mechanism (not shown). A sprocket 28 is rotatably supported on an intermediate portion of the output shaft 23, and the sprocket 28 is rotated by the 2 / 4-wheel switching device C.
It is selectively connected to 23. That is, the clutch teeth 28a are integrally formed on the sprocket 28, and the switching sleeve 29
The clutch teeth 28a are connected to the output shaft 23 by sliding the shaft 28 in the axial direction. The sprocket 28 is connected via a chain 32 to a sprocket 31 that is integrally provided on the front wheel drive shaft 30.

The transmission main body A is housed inside the clutch housing 33 and the transmission case 34, and the auxiliary transmission B is housed inside the transfer case 35 fixed to the rear end surface of the transmission case 34, and the two and four wheels are arranged. Switching device C is a transfer case
It is housed inside 35 and a transfer cover 36 fixed to the rear end surface. Then, the input shaft 1 and the counter shaft 3
The front end of the shaft is supported by the clutch housing 33 via bearings 37, 38, and the rear parts of the intermediate shaft 2 and the auxiliary shaft 3 are supported by the transmission case 34 via bearings 39, 40.
Further, the central portion of the output shaft 23 and the rear end portion of the auxiliary shaft 3 are supported by a transfer case 35 via bearings 41 and 42, and the central rear portion of the output shaft 23 is supported by a transfer cover 36 via a bearing 43. Supported by.

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

When driving with two wheels, the switching sleeve 29 of the two- and four-wheel switching device C is used.
To the left. Then, a 1-2 speed switching synchronization device
By operating the 15th, 3rd-4th speed switching synchronizer 11 or the fifth speed switching synchronizer 8, the vehicle can travel at a desired gear ratio. When the auxiliary transmission B is shifted to the high speed ratio side, the auxiliary shaft 3 is moved from the input shaft 1 via the speed change gear pair.
To the intermediate shaft 2 via the gear pairs 20,10. Since the intermediate shaft 2 and the output shaft 23 are directly connected to each other, the output shaft 23 has a gear ratio of each gear pair and a gear pair 20,1.
It is driven at a gear ratio that is given by the product of a reduction ratio of 0. Since the gear pair 20,10 is provided at the rear of the speed change gear pair, the synchronizers 15,11,8 are not affected by the reduction ratio of the gear pair 20,10, and each synchronizer 15,11,8. The inertial weight acting on is reduced, and the synchronization performance can be improved.

Further, when the auxiliary transmission B is shifted to the low speed ratio side during two-wheel drive, the auxiliary shaft 3 is moved from the input shaft 1 via the speed change gear pair.
Pair of gears provided on the extension 3a of the counter shaft 3 after power is transmitted to
Power is transmitted to the output shaft 23 via the switching sleeve 26 of the auxiliary transmission B via 27, 25. In this case, the output shaft
The gear 23 is driven at a gear ratio given by the product of the gear ratio of each gear pair and the reduction ratio of the gear pair 27, 25. Gear pair 27,25
Since the reduction ratio of is larger than the reduction ratio of the gear pairs 20, 10, it is possible to travel with a larger driving force. In addition, the auxiliary transmission B
Can be used in combination with the other speed change synchronization devices 15, 11, and 8, it is possible to realize a double speed, that is, 10 forward speeds and 2 reverse speeds. Therefore, the auxiliary gear ratio can be used even when the vehicle moves backward, which cannot be used conventionally.

At the time of four-wheel drive, the switching sleeve 29 of the 2 / 4-wheel switching device C
To the right to connect the output shaft 23 and the sprocket 28. It is the same as the two-wheel drive, except that a part of the power of the output shaft 23 is distributed to the front wheels via the chain 32.

-Other Modifications-The present invention is not limited to the transmission having the fifth forward speed and the first reverse gear as in the embodiment, but can be applied to a transmission having other speeds. Further, the auxiliary transmission of the present invention can be applied not only to the four-wheel drive transmission as in the embodiment but also to the two-wheel drive transmission.

Further, in the above-mentioned embodiment, the example in which the extension portion of the counter shaft is integrally provided is shown, but the present invention is not limited to this, and the counter shaft and the extension portion thereof are configured separately, and the extension portion is provided with respect to the counter shaft. May be connected by a spline or the like. In this case, the third gear may be integrally provided on the extension portion.

〔The invention's effect〕

As is clear from the above description, according to the present invention, since the auxiliary transmission is composed of one pair of gears, the number of parts is small,
Can be lightened. Moreover, since the counter shaft and its extension are located coaxially, there is no need to shift the bearing in the radial direction.
A small auxiliary transmission can be realized.

Further, since the auxiliary transmission is arranged on the output side of the transmission, the influence of the increase in torque due to the auxiliary transmission does not reach the transmission gear pair and the synchronizing device as in the conventional case, and the burden on the shifting gear and the synchronizing device is reduced. Do not increase.

[Brief description of drawings]

FIG. 1 is a sectional view of an example in which the present invention is applied to a four-wheel drive transmission, and FIG. 2 is a skeleton diagram of FIG. A: transmission main body, B: auxiliary transmission, C: 2.4
Wheel switching device, 1 ... input shaft, 2 ... intermediate shaft, 3 ... spindle, 3a ... extension part, 8 ... 5 speed switching synchronizer, 10 ...
2nd gear, 11 ...... 3-4 speed change synchronizer, 15 ...... 1-
2nd speed switching synchronizer, 20 …… first gear, 21 …… high / low speed switching device, 22a, 25a …… clutch teeth, 23 …… output shaft, 25
... 4th gear, 27 ... 3rd gear, 26 ... switching sleeve.

Claims (1)

[Claims] 1. An input shaft driven by an engine, an intermediate shaft coaxially arranged behind the input shaft, an output shaft coaxially arranged behind the intermediate shaft, and these shafts. A pair of speed change gears that are provided in parallel and that form a predetermined speed stage between the input shaft and the front portion of the auxiliary shaft are provided, and these speed change gear pairs are selectively driven to A synchronizer that realizes one gear ratio is provided, the first gear is fixed to the rear portion of the counter shaft, and the second gear that meshes with the first gear of the counter shaft is fixed to the intermediate shaft, and A switching device for switching between a direct connection stage in which both shafts are directly connected and a non-direct connection stage in which both shafts are not directly connected is provided, and a third gear for auxiliary speed change is fixed on the auxiliary shaft behind the first gear and the output shaft is provided. The fourth gear, which meshes with the third gear, is rotatably supported on the upper side, and between the intermediate shaft and the output shaft, And the direct coupled stage is directly connected to the shaft, an output shaft with an auxiliary transmission device with transmission is characterized by providing a high and low speed switching device for switching between an auxiliary gear for connecting the fourth gear.