JP2001234989A - Automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To store a sub-clutch in a transmission case without enlarging the axial-directional dimension, having compatibility with the conventional transmission in the dimension of the transmission case, a storage space on board, and layout of the transmission, enhance the traveling performance, and improve the drivability. SOLUTION: This automatic transmission is provided with an input shaft 1, an output shaft 2, and synchronous mechanisms 16-18 changing over a plurality of transmission gear trains and automatically controls the synchronous mechanisms 16-18 in shifting. This transmission is provided with a power transmission mechanism 5 having a main clutch 51 transmitting or cutting the power of an engine to the input shaft 1, and a torque converter 52 provided in the upstream of the clutch 51; a plurality of fitting shafts 2 and 19 having transmission gears constituting a transmission gear train attached thereto; an intermediate shaft 4 arranged in a position except for on the axis of the fitting shafts 2 and 19; and a sub-clutch 27 provided on the intermediate shaft 4 and variably controlling the transmission torque transmitted from the input shaft 1 to the output shaft 2 in shifting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an automatic transmission based on the structure of a manual transmission.

[0002]

2. Description of the Related Art Based on an existing manual transmission,
A transmission that automates this is known. In this type of automatic transmission, a plurality of transmission gear trains are arranged in the axial direction, and a switching mechanism (for example, a synchronization mechanism) for switching between the transmission gear trains is provided.
The shift change is performed by automatically controlling the switching mechanism by hydraulic pressure. This automatic transmission is superior in power transmission efficiency as compared with a normal automatic transmission (so-called AT) mainly composed of a planetary gear, friction engagement elements (clutch, brake) and the like. Also,
Since the number of parts constituting the transmission can be reduced, the weight can be easily reduced, and the cost advantage is great.

With respect to such an automatic transmission, for example,
Japanese Patent Laying-Open No. 63-2735 discloses a configuration in which a sub-clutch for preventing torque loss during a shift change is added in addition to a main clutch. This sub-clutch is arranged on the axis of the input shaft to which one of the transmission gears of the transmission gear train is attached, specifically, at the end of the input shaft of the transmission (the side opposite to the main clutch). At the time of a shift change, the sub-clutch is set to a half-clutch state by hydraulic pressure while keeping the main clutch interposed between the crankshaft of the engine and the input shaft of the transmission in the engaged state. As a result, a sharp drop in output torque during a shift change is suppressed, and a shift shock including a decrease in the feeling of acceleration during an upshift is alleviated. It should be noted that Japanese Unexamined Patent Publication No. 61-45163 and Japanese Patent No. 2703169 also disclose an automatic transmission having a similar configuration.

Japanese Patent Application Laid-Open No. 58-149443 discloses a configuration in which a sub-clutch is arranged on the axis of a counter shaft arranged in parallel to an input shaft and an output shaft. 4 and 5). Specifically, a drive gear of a second gear train and a drive gear of a fourth gear train are rotatably mounted on the counter shaft, and a switching mechanism is interposed between these drive gears. ing. Driven gears of these transmission gear trains are fixedly mounted on an output shaft arranged in parallel with the counter shaft. A sub-clutch that is engaged and controlled at the time of a shift change is arranged at an end of a counter shaft corresponding to a shaft on which a transmission gear (drive gear) is mounted. Further, this publication also discloses a configuration in which the power of an engine is transmitted via a torque converter to an input shaft of an automatic transmission having the above structure.

[0005]

In the above-mentioned conventional automatic transmission, the sub-clutch is arranged on the axis of the input shaft or the counter shaft corresponding to the shaft on which the transmission gear is mounted. Usually, a transmission mechanism including a plurality of transmission gear trains, switching mechanisms, and the like is arranged on the mounting shaft over substantially the entire area in the axial direction. Therefore, when the sub-clutch is mounted on such a mounting shaft, it is necessary to increase the axial dimension of the mounting shaft in order to secure a storage space for the sub-clutch. As a result, the axial size of the transmission case itself is increased as compared with the manual transmission serving as the base. As a result, it becomes difficult to maintain compatibility with the conventional transmission (for example, a manual transmission) with respect to the axial dimension of the transmission case and the storage space on the vehicle.

It is an object of the present invention to accommodate the sub-clutch in the transmission case without increasing the axial dimension.

It is another object of the present invention to improve compatibility with conventional transmissions in terms of the dimensions of the transmission case, the storage space on the vehicle, the layout of the transmission, and the like.

Further, another object of the present invention is to improve the drivability by improving the traveling performance and the towability.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has an input shaft, an output shaft, and a switching mechanism for switching a plurality of transmission gear trains. In an automatic transmission in which a mechanism is automatically controlled, power transmission means having a first clutch for transmitting or interrupting the power of an engine to an input shaft, a torque converter provided upstream of the first clutch, and a transmission gear A plurality of mounting shafts to which the transmission gears constituting the row are mounted, an intermediate shaft arranged at a position other than on the axis of the mounting shaft, and provided on the intermediate shaft, and at the time of a shift change, from the input shaft. An automatic transmission having a second clutch whose transmission torque transmitted to an output shaft is variably controlled.

Here, it is preferable that the power transmission means further includes a lock-up clutch. In this case, it is desirable to control the engagement of the first clutch, the second clutch, and the lock-up clutch according to the operating state.

Further, a first gear train for transmitting the power of the input shaft to the intermediate shaft and a second gear train for transmitting the power of the intermediate shaft to the output shaft may be further provided. In this case, at the time of a shift change, a power transmission path including the second clutch is set via the first gear train and the second gear train.

It is preferable that at least one of the first gear train and the second gear train includes a transmission gear constituting a transmission gear train.

[0013] Further, the first gear train or the second gear train may have a speed increasing or reducing gear ratio.
It is preferable that the total gear ratio of the gear train including the first gear train and the second gear train is a gear ratio corresponding to the speed ratio from the third speed to the fourth speed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG.
FIG. 4 is a skeleton diagram showing an automatic transmission with five forward speeds according to the embodiment. This transmission shown as an example is an automatic transmission for FR drive laid out vertically on a vehicle. In the transmission case, an input shaft 1, an output shaft 2, an idler shaft 3, an intermediate shaft 4 and a counter shaft 19 are arranged in parallel with each other, and in particular, the input and output shafts 1 and 2 are arranged on the same axis. ing. Here, the intermediate shaft 4 is
A counter shaft 19 corresponding to one of the mounting shafts of the transmission gear;
, And at a position other than the axis of the output shaft 2 corresponding to the other mounting shaft of the transmission gear. Basically, the power transmitted from the engine to the input shaft 1 is transmitted to the counter shaft 19 via the gear trains 12 and 13 and transmitted to the output shaft 2 via the specific transmission gear train.

Power on the crankshaft side of the engine is transmitted to the input shaft 1 via a power transmission mechanism 5. The power transmission mechanism 5 includes a multi-plate or single-plate wet main clutch 51.
, A fluid torque converter 52 and a lock-up clutch 53. The torque converter 52 itself has a known structure. The impeller 52a rotates integrally with the crankshaft, and the turbine 52b rotates integrally with the input shaft 1. A one-way clutch 52d is attached to the stator 52c. In the torque converter range (a state in which the rotation difference between impeller 52a and turbine 52b is large), the power of the engine is increased by the torque increasing action of torque converter 52 and then transmitted to turbine 52b. In the coupling range (in a state where both the turbine 52b and the impeller 52a rotate at high speed and the stator 52c idles), the same operation as that of the fluid coupling is performed, so that such a torque increasing operation does not occur. Further, in order to improve the fuel efficiency, the lock-up clutch 53 is engaged according to the driving condition, and the impeller 52a and the turbine 52b are directly connected. The power transmitted to the turbine 52b side of the torque converter 52 is transmitted to the input shaft 1 via the main clutch 51 on the downstream side. The main clutch 51 transmits the power on the input side (the clutch drum side in the present embodiment) to the input shaft 1 or cuts off the power by the hydraulic control.

Input shaft 1, output shaft 2, and counter shaft 19
Between them, there are provided a plurality of speed change gear trains defining respective speed ratios from the first speed to the fifth speed. Regarding the forward speed change gear train, the gear trains 12, 13, the third speed gear train 10, 11, the second speed gear train 8, 9, the first speed gear train 6,
The seventh and fifth speed gear trains 14 and 15 are arranged in this order. The first speed drive gear 6 is fixedly attached to the counter shaft 19. The first-speed driven gear 7 meshed with the drive gear 6 is rotatably attached to the output shaft 2. Similarly, the second speed drive gear 8 is fixedly attached to the counter shaft 19, and the second speed driven gear 9 meshed with the drive gear 8 is rotatably attached to the output shaft 2. On the other hand, the third speed drive gear 10 is fixedly attached to the counter shaft 19, and the third speed driven gear 11 meshed with the drive gear 10 is rotatably attached to the output shaft 2. Further, a gear 12 fixedly attached to the input shaft 1 and a synchronizing mechanism 17 which can be directly connected to the gear 12 are provided on the output shaft 2. Further, the fifth speed drive gear 14 is rotatably attached to the counter shaft 19, and the fifth speed driven gear 15 meshed with the drive gear 14 is fixedly attached to the output shaft 2. It should be noted that the gear ratio of each gear is defined by the gear ratio of the corresponding gear train. However, only in the fourth speed, since the input shaft 1 and the output shaft 2 are directly connected, the gear ratio becomes 1.

The switching of each forward gear train is performed by three synchronizing mechanisms 16-18. The first synchronization mechanism 16 is provided on the output shaft 2 between the first speed driven gear 7 and the second speed driven gear 9. Further, the second synchronizing mechanism 17 includes a three-speed driven gear 11.
And on the output shaft 2 between the first and fourth gears 12. Further, the third synchronizing mechanism 18 is provided on the counter shaft 19 near the left side of the fifth speed drive gear 14. Although the structures of the synchro mechanisms 16 to 18 are well known, the shift of the synchro sleeves constituting the synchro mechanisms 16 to 18 in the axial direction is automatically controlled by hydraulic pressure. The automatic control of this shift is actually performed in cooperation with the transmission torque control of the sub clutch 27 described later. The shift operation of the synchronization mechanisms 16 to 18 will be described. For example, when the gear is set to the first speed,
After setting the synchro mechanisms 17 and 18 to the neutral state (the synchro sleeve is in the neutral position), the synchro sleeve of the synchro mechanism 16 is shifted rightward by hydraulic pressure. As the shift amount increases, the rotation of the synchronization sleeve of the synchronization mechanism 16 and the rotation of the first-speed driven gear 7 are synchronized. When these rotating members are synchronized, the outer spline integrally formed with the first speed driven gear 7 is spline-fitted with the inner spline of the synchro sleeve. Here, the synchro sleeves of the respective synchro mechanisms 16 to 18 are always spline-fitted to a synchro hub that rotates integrally with the output shaft 2. Therefore, the power of the counter shaft 1 is transmitted to the output shaft 2 via the first transmission gear trains 6 and 7 and the synchronization mechanism 16. on the other hand,
When setting the gear stage to the second speed, the synchronizing mechanism 17, 1
In a state where 8 is set to the neutral state, the synchro sleeve of the synchro mechanism 16 is shifted leftward by hydraulic pressure.
When the gear is set to the third speed or the fourth speed, the synchro sleeve of the synchro mechanism 17 is shifted left and right,
When setting to the fifth speed, the synchro sleeve of the synchro mechanism 18 is shifted to the right (other synchro mechanisms are set to a neutral state).

At the time of forward movement except at the time of a shift change,
The power transmitted to the counter shaft 19 via the counter gear 13 meshing with the fourth speed gear 12 is transmitted to the synchronization mechanisms 16 to 1.
The transmission is transmitted to the output shaft 2 via the transmission gear train selected by the operation of FIG. The power of the output shaft 2 is transmitted to left and right rear wheels via a rear differential device (not shown), and the rear wheels rotate in the forward direction.

On the other hand, at the time of retreat, first, all the synchronizing mechanisms 16 to 18 are set to the neutral state. The reverse drive gear 20 fixedly attached to the counter shaft 19 does not directly mesh with the reverse driven gear 21 fixedly attached to the output shaft 2 (see FIG. 1).
In this state, the idler gear 22 rotatably mounted on the idler shaft 3 slides on the idler shaft 3 in the axial direction, and meshes with both the reverse drive gear 20 and the reverse driven gear 21. Thereby, the counter shaft 19
Is transmitted to the output shaft 2 via the gear trains 20 to 22. When the vehicle is moving backward, power is transmitted to the output shaft 2 via the idler gear 22. Therefore, the rotation direction of the output shaft 2 is opposite to that at the time of forward movement, and the rear wheels rotate in the backward direction. FIG. 1 shows the idler shaft 3 and the idler gear 22 below the reverse gears 20 and 21 in order to clarify the structure. However, it should be noted that the idler gear 22 actually exists at a position where it can mesh with both the gears 20 and 21 (second and third gears described later).
The same applies to the embodiment.

Further, a sub-clutch 27, which is a hydraulically controlled multi-plate clutch, is provided on the intermediate shaft 4 disposed below the counter shaft 19. This sub clutch 27
Has a pair of rotating members, a clutch drum 27a and a clutch hub 27b. At the time of a shift change, the sub-clutch 27 is set to the half-clutch state, so that the input-side gear trains 10 and 40 and the sub-clutch 2
7. A power transmission path via the output gear trains 41, 14, 15 is set between the counter shaft 19 and the output shaft 2.
Specifically, the first intermediate gear 40 is rotatably mounted on the intermediate shaft 4 and meshes with the third speed drive gear 10 fixedly mounted on the counter shaft 19. The first intermediate gear 40 is integrally connected to the clutch drum 27a of the sub clutch 27. Therefore, the power of the counter shaft 19 is input to the sub clutch 27 via the input side gear trains 10 and 40. On the other hand, the clutch hub 27b of the sub clutch 27 is integrally connected to a second intermediate gear 41 fixedly attached to the intermediate shaft 4. The second intermediate gear 41 is in mesh with the fifth speed drive gear 14 rotatably mounted on the counter shaft 19. Therefore, the power output from the sub-clutch 27 (the power on the clutch hub 27b side) is transmitted to the output shaft 2 via the output side gear trains 41, 14, and 15.

The gear ratio of the input-side gear trains 10 and 40 or the output-side gear trains 41 and 14 is set to a speed-up or reduction gear ratio. A shift shock due to a drop in output torque poses a problem in a low-speed shift change such as a first-second speed or a second-third speed, but a driver is uncomfortable in a high-speed shift change such as a fourth-speed fifth speed. There is no big shock to feel. From such a viewpoint, the input-side gear trains 10, 40 and the output-side gear trains 41,
The gear ratio of the total gear train consisting of
The gear ratio is set up to the speed.

The automatic transmission having such a configuration is controlled by the shift control system shown in FIG. 4 (the same applies to second and third embodiments described later). Various signals such as the engine speed Ne, the accelerator opening degree θ (throttle opening degree is also possible), the vehicle speed V, the rotation speed Ni of the input shaft 1, the selected shift speed PG, and the select position SL are transmitted to the shift control unit 31. Is entered. The shift control unit 31 specifies a shift stage corresponding to the current running state from these signals, and outputs an appropriate control signal to the hydraulic circuit 32.
The hydraulic circuit 32 includes an oil pump driven by an engine or an electric motor, an electromagnetic valve, and the like. Also,
The hydraulic circuit 32 supplies the adjusted hydraulic pressure to the hydraulic actuator 33 in accordance with a control signal from the transmission control unit 31, and operates the main clutch 51, the sub clutch 27, and the lock-up clutch 53 with the hydraulic pressure. . Here, the hydraulic actuator 33 includes an actuator that operates the synchronization mechanisms 16 to 18 and an actuator that slides the idler gear 22.

The main clutch 51, the sub clutch 27,
Lock-up clutch 53 and synchronization mechanism 16-1
Reference numeral 8 indicates engagement control in the forward traveling range (D range) according to the driving state.

(Driving state) Main clutch 51 Engagement in principle (disengaged only during downshift) Sub clutch 27 Half-clutch state only during shift change Synchronous mechanisms 16 to 18 Switching according to shift pattern Lock-up / clutch 53 Predetermined vehicle speed Engage in the above speed range

First, when the select position SL is set to the forward running range by the select lever, the synchro sleeve of the synchro mechanism 16 shifts to the first speed drive gear while the synchro mechanisms 17, 18 are maintained in the neutral state. Then, the first gear is selected. Here, when the brake is released and the accelerator is depressed, the main clutch 51 is engaged by the hydraulic pressure from the hydraulic circuit 32 while the lock-up clutch 53 is off. As a result, the power of the engine is transmitted to the torque converter 52 and the main clutch 51.
To the input shaft 1 and the vehicle starts running. At this time, the torque converter 52 in the slip state amplifies the power of the engine and transmits it to the input shaft 1, so that a large driving force is generated. Then, as the vehicle speed V increases, the gears are sequentially shifted up in accordance with the shift pattern programmed in the shift control unit 31. In order to improve fuel efficiency, the lock-up clutch 53 is engaged only in a speed range equal to or higher than a predetermined vehicle speed.

When executing a shift change, the engagement of the sub-clutch 27 is started while the engagement state of the main clutch 51 is maintained, and the clutch is set to a half-clutch state. Thus, a power transmission path via the sub clutch 27 is formed together with a power transmission path via the first speed gear trains 6 and 7. That is, the power of the counter shaft 19 is transmitted to the clutch drum 27a side of the sub clutch 27 via the input side gear trains 10 and 40. Next, the sub-clutch 27
The power on the clutch drum 27a side is transmitted to the clutch hub 27b side in accordance with the degree of engagement. Then, power is transmitted to the output shaft 2 via the output-side gear trains 41, 14, and 15. In such a power transmission path, the fifth speed drive gear 14 functions as an idler gear.

While maintaining the sub-clutch 27 in the half-clutch state, for example, as shown in FIG. 5, the transmission torque of the sub-clutch 27 is variably controlled, and the rotation of the counter shaft 19 and the output shaft 2 is synchronized. . Note that FIG.
7 shows a change in the transmission torque of the sub clutch 27 during an upshift to a high speed. In the power transmission path via the sub clutch 27, the total gear ratio Ia of the input / output gear train is 3
Since the gear ratio is set to a speed ratio (e.g., 1.125) between a speed ratio (e.g., 1.3) and a fourth speed speed ratio (e.g., 1.0), a part of the torque of the counter shaft 19 is
7 flows to the output shaft 2 via the sub-clutch 27 according to the engagement state. When the transmission torque Ta of the sub-clutch 27 becomes equal to the engine torque Te (in other words, when all of the engine torque Te passes through the power transmission path via the sub-clutch 27), the transmission gear trains 6 and 7 for the first speed are transmitted. The transmission torque T1 becomes substantially zero. At this timing, the synchro sleeve of the first synchro mechanism 16 is shifted to the neutral position (1 phase). The first synchronizing mechanism 16 is in the neutral state, and the sub-clutch 27
Is increased, the input side gear trains 10 and 40
And the power via the output side gear trains 41, 14, 15 is output to the output shaft 2. At this time, the gear ratio Ia of the total gear train
Is set to correspond to the gear ratios of the third to fourth gears, the engine speed Ne1 in the first gear decreases toward the third to fourth gears (two phases). In this process, when the engine speed reaches the speed Ne2 corresponding to the second speed, an upshift to the second speed is performed. Then, in accordance with the completion of the upshift, the torque control by the sub-clutch 27 also ends (three phases).

By performing such torque control of the sub-clutch 27, it is possible to reduce a drop in driving force (so-called torque loss), which is a problem at the time of a shift change, particularly an upshift, and to improve shift quality. Can be.

On the other hand, at the time of a downshift, the switching of the synchronizing mechanisms 16 to 18 is executed with the main clutch 51 released to improve controllability. Since the power transmission from the engine is interrupted by the main clutch 51, the torque of the input shaft 1 drops to 0 (the drop of the output torque in the downshift caused by the deceleration is:
It does not matter much for drivability). In this state, the synchronizing mechanisms 16 to 18 to be operated are operated to switch to the transmission gear train to be set.

Thus, at the time of downshift,
After releasing the main clutch 51 to substantially reduce the transmission torque carried by the transmission gear train to zero, the synchronizing mechanisms 16 to 18
Perform the above operations. Thus, the synchro sleeve can be easily shifted, so that the controllability of the shift change can be improved.

As described above, in the automatic transmission according to the present embodiment, the sub-clutch 27 can be efficiently housed without significantly increasing the axial dimension (total length) of the transmission. In a conventional automatic transmission, a shaft on which a transmission gear is mounted (a shaft corresponding to this embodiment is a counter shaft 19).
A transmission mechanism is mounted on the output shaft 2) over almost the entire area in the axial direction. Therefore, when the sub-clutch 27 is mounted on the mounting shaft, it is necessary to increase the shaft length of the mounting shaft by the storage space. On the other hand, in the automatic transmission according to the present embodiment, at a position other than on the axis of the output shaft 2 (or the input shaft 1 arranged coaxially) and at a position other than on the axis of the counter shaft 19. An intermediate shaft 4 is provided separately, and the sub-clutch 2
7 is attached. Therefore, unlike the conventional automatic transmission, there is no need to increase the shaft length of the counter shaft 19 and the output shaft 2. As a result, the axial dimension of the transmission case can be substantially the same as that of a manual transmission having the same number of gears, so that compatibility with conventional transmissions in terms of transmission size can be ensured when mounted on a vehicle. it can.

Further, regarding the layout of the automatic transmission,
There is no need to significantly change the base manual transmission. In particular, the counter shaft 1 which is the mounting shaft of the transmission gear
The layout around 9 and the output shaft 2 is exactly the same as that of the manual transmission. In the present embodiment, this uses the third speed drive gear 10 as the input side gear train of the sub-clutch 27 and the fifth speed gear train 1 as the output side gear train.
4, 15 (the fifth drive gear 14 functions as an idler gear). Therefore, for both the input side gear train and the output side gear train, the counter shaft 1
It is not necessary to add a new gear to the output shaft 9 or the output shaft 2. In this way, if the input / output gear train of the sub-clutch 27 is formed using the transmission gears constituting the transmission gear train, the layout of the transmission gears around the mounting shafts 19 and 2 can be changed little. As a result, components and manufacturing equipment can be efficiently shared between the automatic transmission and the manual transmission as a base thereof.

Further, the automatic transmission according to the present embodiment has a relatively small number of components compared to a normal automatic transmission (AT), so that it is easy to reduce the weight, and the cost advantage is great. Further, since the power transmission efficiency of the transmission is high, the economy (fuel efficiency) can be improved.

At the time of a shift change, the transmission gear train is switched while controlling the transmission torque of the sub-clutch 27 variably and transmitting power via the sub-clutch 27. As a result, a drop in driving force (torque cut) during a shift change can be reduced, so that shift quality can be improved.

Further, by utilizing the torque amplifying effect of the torque converter 52 of the power transmission mechanism 5, it is possible to improve the running performance and the running ability. When the torque converter 52 is not interposed, repeated heavy-duty use, such as starting on a slope, towing when climbing a hill, or escaping from a bad road, causes a problem such as heat generation, wear, or reduced durability of the main clutch 51. Further, when a cooling device is attached to the main clutch 51 as a measure against heat generation, another problem occurs in that the transmission becomes large. Further, the main clutch 51 is used to secure the clutch capacity.
Is increased, the inertia increases, and the load on the synchronization mechanisms 16 to 18 increases.
The durability of 6 to 18 becomes a problem. On the other hand, if the torque converter 52 is provided upstream of the main clutch 51 as in the present embodiment, the power from the engine is amplified by the torque amplifying action, so that a large driving force can be secured. it can. As a result, it is possible to secure a good torpedo even in a running condition in which the load on the transmission is large, and it is possible to improve the durability of the transmission. Further, when turning back in a narrow parking lot or when traveling at extremely low speeds due to traffic congestion, if the creep, which is a phenomenon unique to the torque converter 52, is used, the burden on the driver regarding the operation of the accelerator pedal and the like can be reduced.

(Second Embodiment) FIG. 2 is a skeleton diagram showing a forward five-speed automatic transmission according to a second embodiment. This transmission is equipped with a 4
It is a trunk axle for wheel drive. Note that the same members as those shown in FIG. 1 are denoted by the same reference numerals and description thereof is omitted (the same applies to FIG. 3). The front drive shaft 28 is a shaft that transmits power to the front wheels,
It is rotatably mounted in a state penetrating the inside of the hollow counter shaft 19. Further, the rear drive shaft 29
Is a shaft for transmitting power to the rear wheels. Here, the intermediate shaft 4 is at a position other than on the axis of the counter shaft 19 corresponding to one mounting shaft of the transmission gear, and at a position other than on the axis of the output shaft 2 corresponding to the other mounting shaft of the transmission gear. Are located in

Each forward gear train interposed between the output shaft 2 and the counter shaft 19 is arranged in the axial direction from the left in FIG.
The gear trains 12, 13, the third gear train 10, 11, the second gear train 8, 9, the first gear train 6, 7, the fifth gear train 14, 15 are arranged in this order. The drive gears 6, 8, 10, and 14 in the transmission gear train are fixedly mounted on the counter shaft 19, and the driven gears 7, 9, 11, and
15 is rotatably attached to the output shaft 2. The difference of the arrangement of the synchronization mechanisms 16 to 18 from the first embodiment is that the third synchronization mechanism 18 is different from the first embodiment in that the output shaft 2 between the fifth speed driven gear 15 and the reverse driven gear 21 is connected.
This is the point provided above.

The power of the input shaft 1 transmitted from the engine via the power transmission mechanism 5 is transmitted to the counter shaft 19 via the gear trains 12 and 13. When moving forward,
The power of the counter shaft 19 is transmitted to the output shaft 2 via the forward speed change gear train selected by operating the synchronization mechanisms 16 to 18. The power of the output shaft 2 is distributed to the front drive shaft 28 and the rear drive shaft 29 in the planetary center differential device 25. The power of the front drive shaft 28 is transmitted to the front wheels via the front differential device 26, and the power of the rear drive shaft 29 is transmitted to the rear wheels via a rear differential device (not shown). As a result, the front and rear drive wheels rotate in the forward direction.

A differential limiting mechanism 30 composed of a multi-plate clutch is interposed between the carrier of the planetary center differential device 25 and the rear drive shaft 29. The differential limiting mechanism 30 is provided to ensure good running performance, and directly connects the front and rear drive shafts 28 and 29 according to the running conditions (for example, the degree of wheel slip and the steering angle).

On the other hand, at the time of retreat, the synchronization mechanism 1
6 and 17 are set to the neutral state, and the synchronization mechanism 18 is set.
To the reverse driven gear 21 side. Thereby, the power of the counter shaft 19 is transmitted to the output shaft 2 via the first speed drive gear 6 (functioning as a reverse drive gear (shared)), the idler gear 22, and the reverse driven gear 21. At this time, since the idler gear 22 is interposed, the rotation direction of the output shaft 2 is opposite to that at the time of forward movement, and the front and rear drive wheels rotate in the backward direction.

Further, a sub-clutch 27, whose transmission torque is variably controlled at the time of a shift change, is provided on the intermediate shaft 4 disposed below the counter shaft 19 in the figure.
Specifically, the first intermediate gear 40 is rotatably attached to the intermediate shaft 4 and meshes with the third speed drive gear 10 that rotates integrally with the counter shaft 19. The first intermediate gear 40 is integrally connected to the clutch drum 27a of the sub clutch 27. Therefore, the power of the counter shaft 19 is input to the clutch drum 27a (input side) of the sub clutch 27 via the input side gear trains 10 and 40. On the other hand, the second intermediate gear 41 integrally connected to the clutch hub 27b of the sub clutch 27
The third intermediate gear 42 rotatably attached to the counter shaft 19 is engaged. This third intermediate gear 42
Fourth intermediate gear 43 fixedly attached to output shaft 2
Is engaged. Therefore, the power of the counter shaft 19 is transmitted to the output shaft 2 via the sub clutch 27 according to the degree of engagement of the sub clutch 27.

The gear ratios of the input-side gear trains 10 and 40 or the output-side gear trains 41 to 43 are set to a speed-up or speed-reduction gear ratio. As described above, the gear ratio of the total gear train including the input gear trains 10 and 40 and the output gear trains 41 to 43 is from the third gear to the fourth gear from the viewpoint of reducing the torque shock at the time of shift change on the low speed side. Up to the gear ratio.

As described above, this embodiment has the same effects as those of the first embodiment. In this embodiment,
The layout around the mounting shafts 2 and 19 of the transmission gears is such that the intermediate gears 42 and 4 are attached to the counter shaft 19 and the output shaft 2 respectively.
Except for adding 3, the operation is the same as that of the manual transmission.
That is, the intermediate gears 42 and 43 are added to form the output gear train of the sub-clutch 27, but the third gear drive gear 10 is used as the input gear train. Therefore, it is not necessary to add a new gear to the counter shaft 19 for the input gear train. As described above, if at least one of the gear trains on the input side or the output side of the sub-clutch 27 uses the transmission gears constituting the transmission gear train, the layout change around the mounting shafts 2 and 19 of the transmission gears can be reduced. . As a result, components and manufacturing equipment can be efficiently shared between the automatic transmission and the manual transmission as a base thereof. Further, by providing the torque converter 52 in the power transmission mechanism 5, there is also an effect that traveling performance or stepping performance according to the traveling state can be ensured.

(Third Embodiment) FIG. 3 is a skeleton diagram showing a five-speed forward automatic transmission according to a third embodiment. This transmission is a trunk axle laid out horizontally on the vehicle. In the transmission case, an input shaft 1, an output shaft 2, an intermediate shaft 4, and the like are arranged in parallel with each other. Here, the intermediate shaft 4 is at a position other than on the axis of the input shaft 1 corresponding to one mounting shaft of the transmission gear,
And an output shaft 2 corresponding to the other mounting shaft of the transmission gear.
Are located at positions other than on the axis.

Between the input shaft 1 and the output shaft 2, there are provided a plurality of speed change gear trains for defining respective speed ratios from the first speed to the fifth speed. Regarding the forward speed change gear trains, the first speed gear trains 6, 7, the second speed gear trains 8, 9, the third speed gear trains 10, 11, the fourth speed gear trains 44, 45, and the fifth speed gear are arranged in the axial direction from the left side. Rows 14 and 15 are arranged in this order. The first speed drive gear 6
It is fixedly attached to the input shaft 1. The first-speed driven gear 7 meshed with the drive gear 6 is rotatably attached to the output shaft 2. Similarly, 2
The speed drive gear 8 is fixedly attached to the input shaft 1, and the second speed driven gear 9 meshed with the drive gear 8 is rotatably attached to the output shaft 2. On the other hand, the third-speed drive gear 10 is rotatably attached to the input shaft 1, and is engaged with the drive gear 10.
The speed driven gear 11 is fixedly attached to the output shaft 2. The fourth speed drive gear 44 is rotatably attached to the input shaft 1.
The fourth-speed driven gear 45 meshed with is fixedly attached to the output shaft 2. Furthermore, the fifth speed drive gear 14
Is rotatably mounted on the input shaft 1, and the fifth speed driven gear 15 meshed with the drive gear 14 is fixedly mounted on the output shaft 2. It should be noted that the gear ratio of each gear is defined by the gear ratio of the corresponding gear train.

The first synchronizing mechanism 16 is interposed on the output shaft 2 between the first-speed driven gear 7 and the second-speed driven gear 9, and selects a first-speed or second-speed gear train. Further, the second synchronizing mechanism 17 includes the third speed drive gear 10.
, And is interposed on the input shaft 1 between the first and fourth speed drive gears 44 and selects a third or fourth speed gear train. Further, the third synchronizing mechanism 18 is connected to the fifth speed drive gear 14.
Is mounted on the input shaft 1 near the axial direction.

At the time of forward movement except at the time of a shift change,
The power of the input shaft 1 is supplied to the output shaft 2 via the forward speed change gear train selected by operating the synchronizing mechanisms 16 to 18.
Is transmitted to After being decelerated in accordance with the final reduction ratio of the final reduction gear train 19, it is transmitted to the front differential device 20. Thereby, power is transmitted to the drive wheels, and the drive wheels rotate in the forward direction.

The intermediate shaft 4 disposed below the input shaft 1 is provided with a sub-clutch 27 whose transmission torque is variably controlled during a shift change. Specifically, the first intermediate gear 40 is fixedly attached to an end of the input shaft 1 (the side opposite to the power transmission mechanism 5). The second intermediate gear 41 is rotatably mounted on the intermediate shaft 4 and meshes with the first intermediate gear 40. The second intermediate gear 41 is integrally connected to the clutch drum 27a. On the other hand, the third intermediate gear 42 integrally attached to the clutch hub 27b of the sub clutch 27
Are engaged with the fifth speed drive gear 14. At the time of a shift change, the input-side gear train 4
0, 41, sub clutch 27, output side gear train 42, 1
A power transmission path is formed via the transmission shafts 4 and 15, and a transmission torque according to the engagement state of the sub clutch 27 is transmitted to the output shaft 2.

The gear ratio of the input-side gear trains 40 and 41 or the output-side gear trains 42 and 14 is set to a speed increasing or reducing gear ratio. As described above, the input gear trains 40 and 41 and the output gear trains 42, 14, and 15 are used from the viewpoint of reducing the torque shock at the time of a low-speed shift change.
The gear ratio of the total gear train is set to correspond to the speed ratio from the third speed to the fourth speed.

As described above, in this embodiment, as in the above-described embodiments, the size of the transmission can be interchanged with that of the conventional transmission without increasing the axial size and the vehicle width direction of the transmission. The sub-clutch 27 can be stored efficiently while maintaining the same. At the same time, it is possible to maintain a compact space and secure an advantageous layout in terms of collision and safety. Further, it is more advantageous than a normal AT in terms of productivity, manufacturing cost, weight, transmission efficiency, and the like. In addition, there is an effect that the traveling performance and the towability in accordance with the traveling state can be ensured by the torque amplifying action of the torque converter 52.

When the input / output gear train is formed using the transmission gears, any transmission gear can be used according to the layout of the transmission. Further, in the above-described embodiment, the case where the synchronization mechanism having the synchronization function is used as the switching mechanism of each transmission gear train has been described.
However, if the torque transmission and shift timing of the sub-clutch 27 can be accurately controlled by hydraulic control, a simple switching mechanism (for example, a dock clutch) having no synchronization function may be used.

[0052]

As described above, according to the present invention, the intermediate shaft is arranged at a position other than on the axis of the plurality of mounting shafts to which the transmission gears constituting the transmission gear train are mounted. A sub-clutch whose transmission torque is variably controlled at the time of a shift change is arranged on the intermediate shaft. Thus, the sub-clutch can be efficiently housed in the transmission case without increasing the axial size of the transmission. At the same time, compatibility with a conventional transmission can be improved with respect to the storage space of the transmission mounted on the vehicle or the layout of the transmission. In addition, by using a torque converter, driving performance and torpedo performance are improved, so that drivability can be improved.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram of an automatic transmission according to a first embodiment.

FIG. 2 is a skeleton diagram of an automatic transmission according to a second embodiment.

FIG. 3 is a skeleton diagram of an automatic transmission according to a third embodiment.

FIG. 4 is a block diagram of a shift control system.

FIG. 5 is a timing chart at the time of an upshift.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Input shaft 2 Output shaft 3 Idler shaft 4 Intermediate shaft 5 Power transmission mechanism 6 1st speed drive gear 7 1st speed driven gear 8 2nd speed drive gear 9 2nd speed driven gear 10 3rd speed drive gear 11 3rd speed driven gear 12 4th speed gear 13 Counter gear 14 5 speed drive gear 15 5 speed driven gear 16 1st synchro mechanism 17 2nd synchro mechanism 18 3rd synchro mechanism 19 Counter shaft 20 Reverse drive gear 21 Reverse drive gear 22 Idler gear 25 Planetary center differential device 26 Front differential device 27 Sub-clutch 28 Front drive shaft 29 Rear drive shaft 30 Differential limit mechanism 31 Shift control unit 32 Hydraulic circuit 33 Hydraulic actuator 40 First intermediate gear 41 Second intermediate gear 42 Third intermediate gear 43 4th intermediate gear 44 4th speed drive gear 45 4th speed driven gear 51 main clutch 52 torque converter 53 lockup clutch

Claims (7)

[Claims] An automatic transmission having an input shaft, an output shaft, and a switching mechanism for switching a plurality of transmission gear trains, wherein the switching mechanism is automatically controlled at the time of a shift change. A first transmitting or blocking to the input shaft;
, A power transmission unit having a torque converter provided upstream of the first clutch, a plurality of mounting shafts to which each of the transmission gears constituting the transmission gear train is attached, and an axis of the attachment shaft An intermediate shaft disposed at a position other than the line, and a second clutch provided on the intermediate shaft and variably controlling a transmission torque transmitted from the input shaft to the output shaft during a shift change. An automatic transmission, comprising: 2. The automatic transmission according to claim 1, wherein said power transmission means further includes a lock-up clutch. 3. The first clutch, the second clutch, and the lock-up clutch, according to an operating state,
The automatic transmission according to claim 2, wherein engagement control is performed. 4. A shift system further comprising: a first gear train for transmitting the power of the input shaft to the intermediate shaft; and a second gear train for transmitting the power of the intermediate shaft to the output shaft. 4. A power transmission path including the second clutch is set via the first gear train and the second gear train at the time of a change. Automatic transmission. 5. The automatic transmission according to claim 4, wherein at least one of said first gear train and said second gear train includes a transmission gear constituting said transmission gear train. 6. The automatic transmission according to claim 4, wherein the first gear train or the second gear train has a speed-up or speed-down gear ratio. 7. A total gear ratio of a gear train including the first gear train and the second gear train is a gear ratio corresponding to a speed ratio from a third speed to a fourth speed. Item 7. An automatic transmission according to Item 6.