GB2123102A - Vehicle having transmission device - Google Patents

Abstract

A change-speed transmission for a vehicle wherein the torque of an engine is applied to an input shaft (20) of the transmission through a clutch so as to generate from an output shaft (30) of the transmission device a changed speed or a changed direction of rotation has a one-way brake (39) provided to limit the direction of rotation of an intermediate shaft (23) to only one direction of rotation. The one-way brake may alternatively be provided for the input shaft (20) or a rotating member located to follow the rotation of the input shaft and to rotate in only one direction during the transmission of the torque. Such an arrangement enables a rearward running of the car to be prevented whilst the transmission is in forward ratio and prevents forward movement when the transmission is in reverse. The transmission may be countershaft or planetary (Fig. 6). <IMAGE>

Description

SPECIFICATION Vehicle having transmission device This invention relates to a vehicle having a transmission device.

For starting a motor car stopped on a slope, the clutch is released while the car is held by applying the parking brake and the speed changer or transmission device is shifted to the low speed forward driving position. Then, while releasing the parking brake, the clutch is engaged and the accelerator pedal is depressed to start the car so that the car does not move rearwardly. Such a driving operation requires skill and is difficult for an unskilled driver. Otherwise, the car may move rearwardly to collide against a following car, or the engine may stop.

It is an object of this invention to provide a vehicle having a transmission device for facilitating the starting of the vehicle on a slope.

The invention makes it possible to provide a vehicle having a transmission device for preventing a rearward movement of the vehicle when it is started on a slope, thus preventing collision against a following car and alleviating acceleration shocks to human bodies.

The invention also makes it possible to provide a vehicle having a transmission device for preventing a rearward movement of the vehicle when it is started on a slope, which is simple in construction and permits a normal operation of the car.

According to this invention, there is provided a vehicle having a transmission device for facilitating the starting of the vehicle- on a slope wherein the torque of the engine is applied to the input shaft of the transmission device through a clutch so as to generate, from an output of the transmission device, a changed direction or a changed direction of rotation, wherein there is provided a rotation direction limiting means for permitting rotation in only one direction, the means being provided for a rotating member located to follow the input shaft and rotate in only one direction during the transmission of the torque. The means may be one-way clutch or a ratchet wheel.

In the accompanying drawings; Figures 1, 2 and 3 are diagrammatic representations for explaining the operation of a transmission device; Figure 4 is a diagrammatic sectional view showing one embodiment of the vehicle having the transmission device, according to this invention; Figure 5 is a fragmentally sectional view showing another example of an intermediate shaft; and Figure 6 is a diagrammatic representation showing a modified embodiment of this invention.

Before describing the invention, the operation of a transmission device commonly utilized in a motor car will firstly be described with reference to Figs. 1 and 2. In these figures, reference numenal 1 designates an internal combustion engine, 2 a transmission device and 3 a clutch for transmitting and disconnecting engine power to and from the transmission device 2. Reference numeral 4 designates the input shaft of the transmission device, 5 a gear secured to the input shaft 4, 6 the output shaft of the transmission device which is coaxial with the input shaft 4 and journalled by a bearing 7, and 8 and 9 designate gears mounted on the output shaft 6 through a spline to be slidable in the axial direction but rotate with the output shaft.

Reference numeral 10 designates an intermediate shaft, 11, 1 2 and 1 3 gears secured to the intermediate shaft 10, and 14 an idle shaft.

Fig. 1 shows the neutral state in which, when the clutch 3 is engaged, the rotation of the engine 1 is transmitted to the input shaft 4 so that the shaft 4 rotates in the same direction as the engine 1. This rotation in the same direction as the engine 1. This rotation is transmitted to the intermediate shaft 10 through the intermeshing gears 5 and 11 so that the intermediate shaft 10 rotates in the direction opposite that of the input shaft 4. At this time, the idle gear 1 4 rotates in the direction opposite that of the intermediate gear 10. In the state shown in Fig. 1, gears 8 and 9 and the output shaft 6 do not rotate.

When a forward running state is estabiished by shifting the gear 8 in the direction of the arrow A in Fig. 1 to mesh with the gear 12, the output shaft 6 rotates in the direction opposite that of the intermediate shaft 10 (but in the same direction as the input shaft 4).

The rotation of the output shaft 6 is transmitted to the axle through a propeller shaft and a differential gear, not shown, to run the car in the forward direction.

When a rearward running state is established by shifting the gear 9 in the direction of the arrow B to mesh with the idle gear 14, the output shaft 6 and the intermediate shaft 10 rotate in the same direction (but in the direction opposite that of the input shaft 4), whereby the car runs in the rearward direction.

Accordingly, the input shaft 4, the intermediate shaft 10 and the gears secured thereto rotate in only one direction (as shown by the solid line arrows in Fig. 1) corresponding to the direction of power transmission for both the forward and rearward runnings, but the output shaft 6 and the gears mounted thereon in the direction of rotation rotate in one direction for a forward movement of the car and in another for a rearward movement. Thus, the shafts as well as the gears rotate in two directions (as shown by solid line and dotted line arrows in Fig. 1).

A forward starting on a slope will now be described with reference to Fig. 2.

For forwardly starting a motor car on an ascending slope, the transmission gear 2 is operated, while the clutch 3 is being disengaged and the parking brake is being applied to shift the gear 8 to engage the gear 1 2 thereby establishing a forward running state (usually the first speed) as shown in Fig. 2.

Then the clutch 3 is gradually engaged and the parking brake is released. At the same time, the accelerator pedal is depressed to increase the output of the engine. In this case, if the parking brake is released earlier than the engagement of the clutch 3, no braking force and no driving power would be applied to the car with a result that the car moves down the slope due to its weight.

Moreover, the output shaft 6 is rotated by the axle in the direction of the dotted line arrow, and due to the engagement of the gears 8 and 12, the intermediate shaft 10 rotates in the direction of the dotted line arrow. Further, due to the engagement of the gears 11 and 5, the input shaft 4 rotates in the direction of the dotted line arrow.

The same operation is performed for the car to be started to run rearwardly on a descending slope. However, since in this case the gear 9 is engaged to the idle gear 14 as shown in Fig. 3 for the rearward running, when the car runs forwardly on the descending slope by its own weight contrary to the intension of the driver, the output shaft 6 would be driven in the direction of the dotted arrow due to the rotation of the axle. Further, due to the engagement of the gears 9 and 1 3 with the idle gear 14, the intermediate shaft 10 would be rotated in the direction of the solid line arrow and the input shaft 4 in the direction of the solid line arrow as shown in Fig. 3.

In both the cases shown in Figs. 2 and 3, the intermediate shaft 10 and the input shaft 4 rotate in the same direction.

As above described, the object of the invention is to provide a vehicle having a transmission device that can prevent the vehicle from moving in a direction opposite that intended by the driver when the vehicle is started on a slope.

To this end, according to this invention, there is provided a means for preventing a reverse rotation of such member as the input shaft and the intermediate shaft which always rotate in only one direction during the forward running and the rearward running of the car while the rotating power is transmitted.

Preferred embodiments of this invention will now be described with reference to Figs. 4, 5 and 6.

Fig. 4 shows one embodiment wherein the invention is applied to a four-stage speed changer or transmission device, in which ref erence numeral 20 designates an inlet shaft secured to a clutch disc, not shown, 21 a bearing for rotatably supporting the input shaft 20, 22 a gear formed integral with the input shaft 20, 23 an intermediate shaft, 24 and 25 bearings rotatably supporting the intermediate shaft 23, and 26, 27, 28 and 29 are gears integrally formed with the intermediate shaft 23. Reference numeral 30 designates an output shaft coaxial with the input shaft 20 with its forward end rotatably supported by the input shaft and the rear end journalled by a bearing 31, then 32, 33 and 34 gears rotatably mounted on the output shaft 30, and 35 and 36 well known synchronizers provided for the output shaft 30.Reference numeral 37 designates a gear secured to the intermediate shaft 23, and 38 a gear secured to the output shaft 30. Reference numeral 39 represents a one way clutch with its inner race secured to the intermediate shaft 23 and the outer race secured to the casing of the transmission device, so that the direction of rotation of the intermediate shaft 23 is limited to the direction of the solid line arrow.

One-way clutches themselves are known, however, examples being those, of a roller type having cylindrical rollers and inclined cams used and of a sprag type using rollers of a special cross section, as referred to on pages 15-16 and 1 5-1 7 in the revised, fourth edition of the Handbook of Mechanical Engineering published by the Institute of Mechanical Engineering on March 25, 1966.

Since the gears 22 and 26, gears 27 and 32, gears 28 and 33, and gears 29 and 34 normally engage each other, when the clutch is engaged so that the rotation of the engine is transmitted to the input shaft 20, the gears 32, 33 and 34 are rotating. When the synchronizer 36 is moved to the right as a result of the operation of the transmission device, the gear 34 is coupled with the output shaft 30 so that the output shaft 30 is rotated at the first speed in the direction to advance the car. On the other hand, when the synchronizer 36 is moved to the left, the gear 33 is coupled with the output shaft 30 to establish the second speed state. As the synchronizer 35 is moved to the right, the gear 32 is coupled with the output shaft 30 to establish the third speed state, whereas when the synchronizer 35 is moved to the left, the gear 22 is coupled with the output shaft 30 to establish the fourth speed state. Under such a forward running state, the output shaft 30 rotates in the direction shown by the solid line arrows. When an idle gear, not shown, engages both the gears 37 and 38, the output shaft 30 is brought into the rearward running state to rotate in the direction shown by the dotted line arrow for running the car in the rearward direction. The operations described above are the same as those of the well known four-stage transmission device.

With this apparatus, at the time of starting a car on a slope, even when the parking brake is released while the clutch is not yet engaged, there is no fear of accidentally running rearwardly (in the case of an acclivity) or forwardly (in the case of a declivity) owing to the weight of the car since the intermediate shaft 23 is prevented from rotating except in a direction shown by the arrow.

When the transmission device is kept in the neutral position, the car can be moved along the slope by its own weight by merely releasing the braking since the intermediate shaft 23 and the output shaft 30 are not coupled together.

Thus, according to this invention, even when one-way clutch is used, the car can be run by the same operation as the normal operation.

Although in the embodiment shown in Fig.

4 a one-way clutch is provided for the intermediate shaft, such a clutch may provided for another member that rotates in unison with the intermediate shaft or for the input shaft or another member rotating in unison therewith. Such a one-way clutch may be incorporated into any one of the bearings 21, 24 and 25.

As a means for limiting the direction of rotation, various other devices such as a ratchet wheel and the like can be used instead of the one-way clutch of the type described above.

As shown in Fig. 5, the intermediate shaft 23 may be rotatably supported through a bearing 41 by a central shaft 40 secured to the casing of the transmision device, and the one-way clutch 39 may be mounted on the intermediate shaft 23.

Fig. 6 shows a modified embodiment wherein the invention is applied to an automatic speed changer on an automatic transmission device, in which reference numeral 50 designates a torque converter comprising a fly wheel, a turbine, a pump and a stator, 52 an input shaft, 55 a front clutch, 56 an intermediate shaft, 57 a rear clutch, 58 a front brake band, 59 a primary sun gear, 60 a seconday sun gear, 61 a primary carrier, 62 a rear brake band, 63 a long pinion, 64 a short pinion, and 65 an output shaft. The primary sun gear 59, secondary sun gear 60, long pinion 63 and short pinion 64 constitute a planet gear mechanism. Since such a Borg Warner type automatic transmission device is well known in the art, its construction and operation will not be described herein.

According to this invention one-way clutch 66 is provided for limiting the direction of rotation. The inner race of the one-way clutch is secured to the input shaft of the transmission device, while the outer race is secured to the casing of the transmission device. As a consequence, the input shaft can rotate in only one direction, thereby facilitating the starting of a car on a slope in the same manner as the previous embodiment.

The one-way clutch can also be provided for a member which rotates in unison with the input shaft 52 instead of directly providing it for the shaft 52. Of course, the invention can also be applied to any automatic transmission device other than of the Borg-Warner type.

In addition to the embodiments described above, the means for limiting the direction of rotation can be provided for any member which, is rotated in only one direction according to the direction of power transmission and located following the input shaft of the transmission device.

As above described, the vehicle of this invention facilitates the starting of the vehicle on a slope without the danger of running reawardly, thus preventing the danger of colliding against the following car as well as the possibilities of the engine stopping. Further, because the object of this invention can be achieved by adding such a simple device as a one-way clutch, the cost does not increase appreciably and the chance of fault does not increase.

Moreover, at the time of collision, since the car is locked not to run, although the car may be damaged, acceleration shocks to human bodies can be alleviated. Still further, the normal running operation is the same as that of a conventional motor vehicle.

Also, the invention is not limited to the embodiments described above and a number of other applications as well as variations are feasible. For example, a one-way clutch can be disposed on the input shaft itself of a transmission device as indicated in Fig. 4 with reference numeral 100. Since the rotation torque of the input shaft is comparatively small in this instance, a small one-way clutch suffices. As for the vehicles, it goes without saying that the invention is applicable not only to motor cars having internal combustion engines but also to electric motor cars having transmission devices.

Claims (10)

1. A transmission device for a vehicle wherein the torque of an engine is applied in use to an input shaft of the transmission device through a clutch so as to separate, from an output shaft of the transmission device, a changed speed or a changed direction of rotation, and wherein there is provided a rotating member for rotating in only one direction during the transmission of said torque, and a rotation direction limiting means mounted on said rotating member, for permitting rotation of said rotating member in only said direction.

2. A transmission device according to Claim 1, wherein said rotating member is the input shaft of said transmission device.

3. A transmission device according to Claim 1, wherein said rotating member is located to follow the rotation of said input shaft.

4. A transmission device according to any of Claims 1 to 3 wherein said rotation direction limiting means comprises a one-way clutch with an inner race secured to said rotating member of said transmission device and an outer race secured to a casing of said transmission device.

5. A transmission device according to any of Claims 1 to 3 wherein said rotating direction limiting means comprises a ratchet wheel.

6. A transmission device according to Claim 2 wherein said rotation direction limiting means is incorporated into a bearing journaling said rotating member.

7. A transmission device according to Claim 1 wherein said rotating member of said transmission device is rotatably supported by a shaft secured to the casing of said transmission device.

8. A transmission device according to Claim 1 wherein said transmission device comprises an automatic transmission device and said rotation direction limiting means is provided on the input side of said automatic transmission device.

9. A transmission device substantially as hereinbefore described with reference to, and as illustrated in, Fig. 4, or Fig. 5, or Fig. 6 of the accompanying drawings.

10. A vehicle having a transmission device as claimed in any preceding Claim.