JP3126770B2 - Vehicle with multi-stage automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive system for a vehicle having a center differential device,
The present invention relates to a structure capable of maximizing commonality of a two-wheel drive vehicle such as a FF and a two-wheel drive vehicle.

[0002]

2. Description of the Related Art In general, a center differential device is mounted on a four-wheel drive vehicle, and a conventional four-wheel drive vehicle is disclosed, for example, in Japanese Patent Application No. 2-134306. Here, a hydraulic multi-plate clutch for power connection and disconnection to a center differential device of the compound planetary gear,
A hydraulic multi-plate clutch for limiting the differential and variably controlling the torque distribution, and a brake for obtaining the fifth speed, are provided and arranged sequentially in the axial direction. And the differential function by the center differential device,
In addition to providing the function of dividing the torque to the front and rear wheels, the torque distribution to the front and rear wheels is variably controlled, and the driving performance, maneuverability, stability, braking performance, etc. are further improved by using it as a deceleration or speed increasing device. It is shown to do.

[0003]

However, since the above-mentioned prior art is configured only for a four-wheel drive vehicle, it is adapted to a two-wheel drive vehicle such as an FF using this drive system. Absent. Here, the center differential device also has a function as a sub-transmission that obtains a deceleration or speed-up shift speed, and since this function is also effective for a two-wheel drive vehicle, the same drive system components are used. It is desired to use the configuration so as to maximize the commonality of the four-wheel drive vehicle and the two-wheel drive vehicle.

The present invention has been made in view of this point, and uses the same driving system components including a multifunctional center differential device and a hydraulic multi-plate clutch device to provide a four-wheel drive vehicle and a two-wheel drive vehicle. The purpose is to easily obtain common vehicles.

[0005]

To achieve the above object, the present invention provides a first sun gear connected to an output shaft of an automatic transmission inside a transfer case joined to a transmission case of the automatic transmission. A second sun gear engaged with the first output shaft, a pair of pinions meshed with the first sun gear and the second sun gear, respectively, and coaxially arranged in series and integrally formed; A second pinion that rotatably supports the pinion around the first and second sun gears and outputs the pinion to one of the drive shafts of the front and rear wheels;
And a plurality of frictional engagement elements are arranged, wherein the frictional engagement element includes the first output shaft and the second output shaft. Fasten with output shaft
A first friction engagement element to be disengaged, and a second frictional member for engaging and disengaging the first output shaft and the transfer case to obtain a deceleration or speed-up shift speed other than a shift speed of the automatic transmission. And a combination element.

[0006]

According to the above construction, the transmission is transmitted from the compound planetary gear to the other one of the front and rear wheels, thereby realizing the original four-wheel drive vehicle.
And a second frictional engagement element are provided, and the first output shaft and the second output shaft are engaged by the first frictional engagement element.
It becomes a multi-stage automatic transmission for wheel drive vehicles. In this multi-stage automatic transmission for a two-wheel drive vehicle, the components of the compound planetary gear are fastened by the engagement of the first frictional engagement element, and the shifting power of the automatic transmission is transmitted as it is. The speed increasing function is given to the compound type planetary gear by the engagement of the friction engagement element, and it is possible to obtain a reduced or increased speed other than the speed included in the automatic transmission.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a case of an original four-wheel drive vehicle as a vehicle with a center differential device to which the present invention is applied will be described. A description will be given of a drive system according to an embodiment in which an engine and an automatic transmission are vertically arranged in the vehicle front-rear direction as the four-wheel drive vehicle. A transmission case 3 is joined to a rear portion of a torque converter case 1 and a differential case 2, 3
The transfer case 4 and the extension case 6 are joined to the rear part of the transfer case 4. Also, transmission case 3
An oil pan 5 is attached to the lower part of the oil pan.

Reference numeral 10 denotes an engine. A crankshaft 11 of the engine 10 is connected to a torque converter 13 having a lock-up clutch 12 inside the torque converter case 1, and an input shaft 14 from the torque converter 13.
Is input to the automatic transmission 30 inside the transmission case 3. The transmission output shaft 15 from the automatic transmission 30 outputs coaxially with the input shaft 14, and this transmission output shaft 15 is coaxially connected to a center differential device 50 inside the transfer case 4.

Inside the transmission case 3, a front drive shaft 16 is disposed parallel to the input and output shafts 14 and 15, and a rear end of the front drive shaft 16 is connected to a center differential device 50 by a pair of reduction gears 17 and 18. The front end of the front drive shaft 16 is transmitted to the front wheels via a front differential device 19 inside the differential case 2. On the other hand, a hydraulic multi-plate clutch device 60 is provided at the rear of the center differential device 50. The rear drive shaft 20 output from the hydraulic multi-plate clutch device 60 is rearwardly transmitted via a propeller shaft 21, a rear differential device 22, and the like. Driven by wheels.

The automatic transmission 30 is configured to obtain four forward speeds and one reverse speed by two sets of front planetary gears 31 and rear planetary gears 32. That is, the input shaft 14 is connected to the sun gear 32 a of the rear planetary gear 32, and the ring gear 31 b of the front planetary gear 31 and the carrier 32 c of the rear planetary gear 32 are connected to the transmission output shaft 15. And the carrier 3 of the front planetary gear 31
A first one-way clutch 34 and a forward clutch 35 are provided in series between a connecting element 33 integral with 1c and the ring gear 32b, and a first one-way clutch 34 and a forward clutch 35 are provided between the connecting element 33 and a case side as a fixing member. 2 one-way clutch 3
6. A low reverse brake 37 is provided in parallel.
An overrunning clutch 38 is provided between the coupling element 33 and the ring gear 32b in a bypass manner.

A connecting element 39 integral with the sun gear 31a is provided with a band brake 40, and the input shaft 14
A high clutch 43 is provided between the connecting element 41 integral with the connecting member 41 and the connecting element 42 integral with the carrier 31c. Further, a reverse clutch 44 is provided between the connecting elements 39 and 41.

With the construction of the automatic transmission 30, the forward clutch 35 is engaged at the first speed in the D range or the third range and the second range, and in the case of acceleration, the ring gear together with the connecting element 33 is operated by the action of the two one-way clutches 34 and 36. 32
b, the sun gear 32
a, power is transmitted to the transmission output shaft 15 via the carrier 32c. At this time, when coasting, the first one-way clutch 34 becomes free, and even if the overrunning clutch 38 is engaged to restrict the free rotation of the first one-way clutch 34, the second one-way clutch 36 becomes free. The engine brake does not work. At the first speed in one range, the ring gear 32b is always locked via the overrunning clutch 38 by the engagement of the low reverse clutch 37, so that the engine brake operates.

In the second range of the D range or the third range and the second range, the forward clutch 35 and the band brake 4
0 engages, and the band gear 40 locks the sun gear 31a. Therefore, the carrier 31c and the ring gear 32b are connected to the connecting element 33, the forward clutch 3
5, rotating via the first one-way clutch 34,
The motive power output is increased by an amount corresponding to the rotation of the ring gear 32b as compared with the speed. At this time, at the time of deceleration, by maintaining the connecting element 33 and the ring gear 32b in the connected state by the engagement of the overrunning clutch 38, the reverse driving force is transmitted to the engine side and the engine brake acts.

In the third range of the D range or the third range, the forward clutch 35 and the high clutch 43 are engaged, and the input shaft 14 is connected by the high clutch 43 to the connecting element 41,
42, the carrier 31c, the connection element 33, the forward clutch 35, and the first one-way clutch 34 to connect to the ring gear 32b. For this reason, the rear planetary gear 32 is integrated, and the input shaft 14 and the transmission output shaft 15 are directly connected. At this time, when the overrunning clutch 38 is engaged at the time of deceleration, the idling of the first one-way clutch 34 is regulated, so that the engine brake acts as in the case of the second speed.

At the fourth speed in the D range, the sun gear 31a is locked by the engagement of the band brake 40 in addition to the above. Therefore, the high planetary gear 31
3, the ring gear 3 is driven by the power input to the carrier 31c.
1b, which is transmitted to the transmission output shaft 15. In this case, since the first and second one-way clutches 34 and 36 do not intervene, the engine brake always operates.

In the R range, the power of the input shaft 14 is input to the sun gear 31a by the connection of the reverse clutch 44. Further, since the carrier 31c is locked together with the connecting element 33 by the engagement of the low reverse clutch 37, the front planetary gear 31 reversely rotates to the ring gear 31b to output power having a large gear ratio, and this reverse power is transmitted to the transmission output shaft 15. Transmit and go to reverse speed. Thus, the automatic transmission 30 has four forward speeds and one reverse speed.

On the other hand, an oil pump 45 is provided in front of the automatic transmission 30 and is always driven by a drive shaft 46 of the torque converter 13 on the pump impeller side. A control valve body 47 is housed in the oil pan 5, and supplies and discharges oil to and from each of the above-mentioned clutches and brakes to be selectively engaged.

Referring to FIG. 2, the parts of the center differential device 50 and the hydraulic multiple disc clutch device 60 will be described. First, the first and second gears are provided behind the transmission output shaft 15.
The rear drive shaft 20 is arranged coaxially via the intermediate shafts 23 and 24 of the first embodiment. Further, a reduction gear 17 on the front wheel side is rotatably fitted to the transmission output shaft 15, and the transmission output shaft 15, the reduction gear 17, and the first and second reduction gears 17 are provided.
A center differential device 50 is coaxially arranged between the intermediate shafts 23 and 24.

The center differential device 50 is configured as a compound planetary gear, and includes a first sun gear 51 formed on the transmission output shaft 15 and a second sun gear 53 formed on the second intermediate shaft 24. Have. The carrier 55 is formed by integrating left and right flanges 55a and 55b by an arm 55c.
First and second pinions 52 and 54 formed integrally in the axial direction are rotatably mounted via a needle bearing 27 on a pinion shaft 56 mounted between 55b. The first sun gear 51 is provided with the first pinion 52
The second pinion 54 meshes with each of the sun gears 53, and outputs the torque-distributed power to the second intermediate shaft 24.

On the other hand, a first intermediate shaft 23 is further loosely fitted inside the second intermediate shaft 24, and a connecting member is provided at a front end of the first intermediate shaft 23 at a gap between the two sun gears 51 and 53. The connecting member 57 is integrally spline-coupled to the arm 55c of the carrier 55 to perform an operation such as a differential restriction. Further, the reduction gear 17 is coupled to one flange 55 a of the carrier 55 so as to output the power of the carrier 55. Here, the reduction gear 17 integral with the carrier 55 is supported by the ball bearing 26a with respect to the transmission case 3 at the front, and the outer periphery of the boss 55d of the flange 55b is formed with the ball bearing 26b with respect to the transfer case 4 at the rear. It is supported, and its inner periphery is supported by a ball bearing 26c with respect to the second intermediate shaft 24, and is rotatably installed with both ends supported.

This center differential device 50
According to the configuration described above, the power input to the first sun gear 51 is
The torque is transmitted to the carrier 55 and the second sun gear 53 at a torque distribution ratio according to the gear specifications of the first and second sun gears 51 and 53 and the first and second pinions 52 and 54, so that they are unequal to the front and rear wheels. It has a function to distribute torque. In addition, it has a differential function of absorbing a rotational speed difference between the carrier 55 and the second sun gear 53 caused by a difference in turning radius during turning due to the planetary rotation of the first and second pinions 52 and 54.

The unequal torque distribution function of the center differential device 50 will now be described in detail with reference to the schematic diagram of FIG. The input torque of the first sun gear 51 is Ti, the mesh pitch radius thereof is rs1, the front side torque of the carrier 55 is TF, the mesh pitch radii of the first and second pinions 52 and 54 are rp1 and rp2, and the second is Sun gear 53
The rear side torque is TR and the mesh pitch radius is rs2
Then, Ti = TF + TR (1) rs1 + rp1 = rs2 + rp2 (2)

The tangential load P acting on the meshing point between the first sun gear 51 and the first pinion 52 includes the tangential load P1 acting on the carrier 55, the second sun gear 53 and the second pinion. Since it is equal to the sum of the tangential load P2 acting on the meshing point with 54, the following equation is established. P = Ti / rs1 P1 = TF / (rs1 + rp1) P2 = TR / rs2 Ti / rs1 = {(TF / (rs1 + rp1)} + TR / rs2 (3) Then, the equations (1) and (2) are converted into the equation (3). Substituting into the equation and rearranging it gives the following: TF = (1−rp1 · rs2 / rs1 · rp2) × Ti TR = (rp1 · rs2 / rs1 · rp2) × Ti

Thus, the first and second sun gears 5
It can be seen that the reference torque distribution ratio of the front torque TF and the rear torque TR can be set freely by the engagement pitch radii of the first and second pinions 52 and 54 with the first and second pinions 52 and 54. Here, rs1, rp1, rp2, rs2
Can be replaced by the number of teeth Zs1, Zp1, Zp2, Zs2, Zp1 = Zp2 = 21, Zs1 = 33, Z
Assuming that s2 = 21, TF: TR = 36.4: 63.6. Therefore, the reference torque distribution ratio for the rear wheel bias can be set sufficiently.

Next, the center differential device 5
A case where 0 is used as a gearbox will be described. In the composite planetary gear type center differential device 50, a predetermined speed increasing gear ratio can be obtained by fixing the second intermediate shaft 24, and the speed increasing gear ratio alone or the predetermined gear position of the automatic transmission 30 can be obtained. 5th
It is designed to shift to high speed. Therefore, for example, a case where the second speed is used will be described. The fifth speed gear ratio i5 is as follows based on the second speed gear ratio i2 and the speed increasing gear ratio ip of the center differential device 50. i5 = i2 · ip Here, if the above-described gear specifications of the center differential device 50 are used, ip = (33-21) / 3
3 = 0.363. For example, if i2 = 1.545, i5 = 0.561, and the fifth speed having a smaller gear ratio than the fourth speed can be obtained at an appropriate gear ratio interval. On the other hand, at the fifth speed, the transmission torque is generated by controlling the hydraulic pressure of the hydraulic multiple disc clutch 62 according to the traveling state or the road surface condition, and the four-wheel drive in which the torque distribution of the front and rear wheels can be controlled.

In FIG. 3, a hydraulic multiple disc clutch device 60 is shown.
Will be described. First, a hydraulic multi-plate clutch 61 interposed between the second intermediate shaft 24 and the rear drive shaft 20 as a frictional engagement element for transmitting torque, and a first intermediate shaft 23
Multi-disc clutch 6 interposed between the clutch and the rear drive shaft 20 as a frictional engagement element for limiting the differential and moving the torque
2 and the second intermediate shaft 24 to prevent the differential function of the center differential device 50 from being carried out.
And a fifth speed brake 63 as a friction engagement element for increasing the rotational speed of the motor. The hydraulic multi-plate clutches 61 and 62 and the fifth speed brake 63 are connected to the first intermediate shaft 23 immediately after the center differential device 50.
Are superposed three-dimensionally in the radial direction around them and are arranged coaxially. That is, the hydraulic multi-plate clutches 61 and 62 are both connected to the rear drive shaft 20, and the hydraulic multi-plate clutch 61 and the fifth speed brake 63 are both connected to the second intermediate shaft 24. A fifth speed brake 63 is provided outside the hydraulic multi-plate clutch 61.
However, a hydraulic multi-plate clutch 62 is disposed inside.

Therefore, the drum member 6 is attached to the second intermediate shaft 24.
4 is spline-coupled, and a drum member 65 integrally formed with the front end of the rear drive shaft 20 is disposed inside the drum member 64, and a hydraulic multi-plate clutch 61 is provided between the drum members 64 and 65. The hydraulic multi-plate clutch 61 has a drive plate 6 between the drum members 64 and 65.
1a and the driven plate 61b are provided alternately, and a hydraulic chamber 61c, a piston 61d, and a return spring 61e are provided inside the drum member 64, and the second intermediate shaft 24 is provided.
Is connected to or disconnected from the rear drive shaft 20.

The fifth speed brake 63 includes a drum member 64
A drive plate 63a and a driven plate 63b are provided alternately between the transfer case 4 and the transfer case 4. A hydraulic chamber 63c, a piston 63d, and a return spring 63e are provided inside a wall 4a of the transfer case 4, and a second intermediate shaft is provided. 24 is configured to be fixed or free.

The hydraulic multi-plate clutch 62 includes a first intermediate shaft 2
3 and a hub member 66 and a drum member 65 which are spline-connected
, Drive plates 62a and driven plates 62b are provided alternately. Also, the hydraulic chamber 62c, the piston 62d, and the return spring 62e generate a large pressing force inside the boss portion 6a of the fixed-side extension case 6 and accurately control the hydraulic pressure without being affected by the centrifugal hydraulic pressure. Is provided as possible. And
The piston 62d is connected to the plate via a ball bearing 62f and a pressing member 62g, and is configured to generate a variable limiting torque and a transmission torque that are variably controlled. A bush 28 is interposed in the shaft fitting portion, and a thrust bearing 25 is interposed in the abutting portion between the shafts or the shaft and another member.

The hydraulic multi-plate clutches 61 and 62 and the fifth speed brake 63 are provided with a control valve body 4.
At 7, hydraulic control is performed together with shift control of the automatic transmission 30 and the like. That is, when the automatic transmission 30 shifts to four forward speeds and one reverse speed, the fifth speed brake 63 is released and the hydraulic multiple disc clutch 61 is engaged. A differential limiting torque is generated in the multiple disc clutch 62. On the other hand, when the vehicle speed rises above the set value at the fourth speed, the fifth speed brake 63 is engaged to release the hydraulic multiple disc clutch 61, and at this time, the hydraulic multiple disc clutch 62 is Generates transmission torque.

The clutch and brake operation of the automatic transmission 30 and the center differential device 50 in each of the D range and the R range in the R range are summarized in Table 1.

[Table 1] In Table 1, ○ indicates the clutch-brake engagement operation, ● indicates the generation of the differential limiting torque by the hydraulic multi-plate clutch 62, and ◎ indicates the driving force distribution control to the front and rear wheels by the hydraulic multi-plate clutch 62. In this case, the transmission torque state is shown.

Table 2 summarizes the gear ratios, examples of the gear ratios, and the torque distribution ratios at each shift speed.

[Table 2] In Table 2, α1 is the front planetary gear 31
Α1 = Zs1 / Zr1, α2 is the ratio of the number of teeth Zs2 of the sun gear 32a of the rear planetary gear 32 to the number of teeth Zr2 of the ring gear 32b, and α2 = Zs2. / Zr
2 is shown.

The relationship between the number of rotations of each element of the front planetary gear 31 is shown by the following equation. Nr1 + α1 · Ns1 = (1 + α1) · Nc1 where α1 = Zs1 / Zr1 The relationship of the rotation speed of each element of the rear planetary gear 32 is expressed by the following equation. Nr2 + α2 · Ns2 = (1 + α2) · Nc2 where α2 = Zs2 / Zr2 where the ring gear 31 of the front planetary gear 31
b, the rotation speed Ns1 of the sun gear 31a, the rotation speed Nc1 of the carrier 31c, the rotation speed Nr2 of the ring gear 32b of the rear planetary gear 32, the rotation speed Ns2 of the sun gear 32a, and the rotation speed Nc of the carrier 32c.
2.

Next, the operation of this embodiment will be described. First, the power of the engine 10 is the torque converter 1
3, input to the automatic transmission 30 via the input shaft 14, and two sets of front planetary gears 31 and rear planetary gears 3
2, the clutches 44, 43, 35, 38, 36, 3
Due to the selective engagement of the brake 4 and the brakes 40 and 37, when shifting to the D range, the speed is automatically changed to the first to fourth forward speeds, and when shifting to the R range, the reverse speed is achieved. Then, the shifting power is input from the transmission output shaft 15 to the first sun gear 51 of the center differential device 50, and the torque is distributed. In this case, the hydraulic multiple disk clutch 61 of the hydraulic multiple disk clutch device 60 is engaged, and the second sun gear 53 of the center differential device 50 is engaged.
Are connected to the rear drive shaft 20.

Here, the center differential device 5
For example, TF: TR = 36.4:
66.4% of shifting power because it is set to 63.6
Is distributed to the carrier 55 and 63.6% is distributed to the second sun gear 53 and output. The power of the carrier 55 is transmitted to the front wheels via the reduction drive gear 17, the reduction driven gear 18, the front drive shaft 16, and the front differential device 19. The power of the second sun gear 53 is supplied to the second intermediate shaft 24,
The transmission is transmitted to the rear wheels after the hydraulic multi-plate clutch 61 and the rear drive shaft 20, and the rear wheels are biased in four-wheel drive running. In this torque distribution, oversteering is likely to occur, and turning and maneuverability are improved. At the time of this four-wheel drive running turn, the first and second pinions 5 of the center differential device 50 are turned on.
Due to the 2,54 planetary rotations, the difference in the rotational speeds of the front and rear wheels generated at the time of turning is absorbed, and the vehicle can freely turn.

Next, when the vehicle is traveling on a slippery road surface, the rear wheel normally slips first because the reference torque distribution is the rear wheel biased torque distribution. In this case, the differential limiting torque Tc of the hydraulic multi-plate clutch 62 is slipped. It is controlled according to. Then, between the carrier 55 of the center differential device 50 and the second sun gear 53, the carrier 55, the connecting member 57, the first intermediate shaft 23, and the hydraulic multiple disc clutch 6
2 is formed by bypassing the low-speed carrier 5 from the rear wheel side of the high-speed second sun gear 53.
5, a torque bypass is performed on the front wheel side according to the differential limiting torque Tc. Therefore, torque distribution control is performed toward the front wheels to prevent rear wheel slip, thereby improving running performance.

At this time, when the differential limiting torque Tc becomes maximum, the center differential device 50 is locked by the direct connection between the second sun gear 53 and the carrier 55 to be a direct connection type four-wheel drive. The corresponding torque distribution results. By controlling the differential limiting torque Tc in this way, the torque distribution is variably controlled between the rear wheel biased and the direct connection type.

On the other hand, when the speed becomes higher than the fourth speed running condition, the automatic transmission 30 enters the second speed state, and at the same time, the second sun gear of the center differential device 50 is engaged by the engagement of the fifth speed brake 63. 53 is fixed, and the carrier 55 rotates at an increased speed. For this reason, the power of the second speed of the automatic transmission 30 is supplied to the center differential device 50.
And greatly transmitted to the front wheels after the carrier 55,
The speed is shifted to the overdrive fifth speed having a smaller gear ratio than the fourth speed, and the vehicle can run at high speed. In this case, the vehicle tends to be understeered and the stability at high speed is improved. At this time, when the transmission torque TD of the hydraulic multi-plate clutch 62 is variably controlled according to the running state, the state of front wheel slip, and the like, the rear wheel is transmitted from the carrier 55 via the first intermediate shaft 23 and the hydraulic multi-plate clutch 62. The torque is also transmitted. Thus, four-wheel drive traveling is realized in which the front wheel slip is prevented and the torque distribution of the front and rear wheels is similarly controllable.

Referring to FIG. 5, a description will be given of an embodiment in which a multi-stage automatic transmission for a two-wheel drive vehicle is configured by using the drive system components of the four-wheel drive vehicle with the center differential device as described above. That is, in the above-described compound planetary gear type center differential device 50, the power is transmitted so as to always transmit power from the carrier 55 to the front wheels via the pair of reduction gears 17 and 18, so that the center differential device 50 is integrated. The transmission power of the automatic transmission 30 is transmitted to the front wheels as it is. Further, the function as a speed increaser can be obtained from the center differential device 50 by the same means as described above, whereby the automatic transmission for a 5-speed FF vehicle can be obtained.

Therefore, the rear cover 70 is joined to the rear end of the transfer case 4 so as to close, and the rear end of the first intermediate shaft 23 output from the center differential device 50 is connected to the ball bearing 2 by the rear cover 70.
6d. On the other hand, in the center differential device 50, the first
Can be locked by directly connecting the second intermediate shaft 24 integral with the second intermediate shaft 23 and the second sun gear 53. Therefore, in the hydraulic multiple disc clutch device 60, the second
A drum member 64 is provided on the intermediate shaft 24 as described above, and a hub member 71 having a larger diameter than that described above is spline-coupled to the first intermediate shaft 23.
A hydraulic multi-plate clutch 72 for fastening or releasing is provided between the clutch and the hub member 71.

The hydraulic multi-plate clutch 72 includes a drum member 64
A drive plate 72a and a driven plate 72b are provided alternately between the first and second hub members 71, and a hydraulic chamber 72c, a piston 72d, and a return spring 72e are provided inside the drum member 64 as described above. The intermediate shafts 23 and 24 are configured to be connected and disconnected. Further, a fifth speed brake 63 is provided between the drum member 64 and the transfer case 4 as described above.

Next, the operation of this embodiment will be described. When the vehicle speed is lower than a predetermined speed, the hydraulic multi-plate clutch 72 is engaged, whereby the center differential device 50 connects the carrier 55 and the second sun gear 53 to each other. Directly connected and rotate together. Then, the shifting power of four forward steps and one reverse step by the automatic transmission 30 is directly transmitted to the front-wheel-side transmission elements after the center differential device 50, and the vehicle is driven by two-wheel drive. When the vehicle speed is higher than a predetermined vehicle speed, the hydraulic multiple disc clutch 72 is released, the fifth speed brake 63 is engaged, and the automatic transmission 30 is controlled to shift to the second speed. Is shifted.

The hydraulic multiple disc clutch device 60 is configured to lubricate an oil passage, an oil hole, and the like from a first intermediate shaft 23 disposed at the center, and the first intermediate shaft 23 is also used in an FF vehicle. Used as is. Therefore FF
In a vehicle, the lubrication of the hydraulic multiple disc clutch device 60 is performed in exactly the same manner as in a four-wheel drive vehicle.

Although the embodiments of the present invention have been described above, the automatic transmission is not limited to the embodiments, and can be applied to a drive system arranged in a horizontal direction. The center differential device can be adapted to a case where it is composed of a simple planetary gear or a bevel gear, a case where it is used as a reduction gear, or a case where the speed increasing gear ratio itself obtained from the center differential device is used.

[0045]

As described above, according to the present invention, as a vehicle with a center differential device, the same drive system components as those of a four-wheel drive vehicle can be applied to a multi-stage automatic transmission for a two-wheel drive vehicle. Therefore, the common use of the two becomes better, and the flexibility of vehicle type development can be expanded. 2
In the case of a multi-stage automatic transmission for a wheel drive vehicle, another one except for one of the two hydraulic multi-plate clutches of the hydraulic multi-plate clutch device.
Since only one of them is changed slightly, the sharing of members is excellent, the mass productivity is improved, and the cost, maintenance and the like are very advantageous. By obtaining the deceleration or speed-up function from the center differential device, it is possible to improve the traveling performance of a two-wheel drive vehicle.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing an entire drive system of an embodiment of a four-wheel drive vehicle as a vehicle with a center differential device according to the present invention.

FIG. 2 is an enlarged sectional view of a portion of a center differential device and a hydraulic multiple disc clutch device.

FIG. 3 is an enlarged sectional view of a portion of the hydraulic multiple disc clutch device.

FIG. 4 is a schematic diagram illustrating a flow of a torque distribution state, a differential limitation, and a transmission torque for direct connection.

FIG. 5 is a sectional view showing a main part of an embodiment in which the present invention is applied to a two-wheel drive vehicle.

[Explanation of symbols]

Reference Signs List 3 transmission case 4 transfer case 16 front drive shaft 17, 18 reduction gear 30 automatic transmission 50 center differential device 60 hydraulic multiple disc clutch device 63 fifth speed brake (second friction engagement element) 70 rear cover 72 locking hydraulic pressure Multiple disc clutch (first friction engagement element)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60K 17/28-17/36 F16H 48/10 F16H 48/30 F16H 57/00-57/12

Claims (2)

(57) [Claims] An automatic transmission includes a transfer case joined to a transmission case of the automatic transmission.
A first sun gear connected to the output shaft; and a first sun gear connected to the first output shaft.
A second sun gear engaged with the first sun gear;
2 meshed with each other and arranged coaxially in series.
And a pair of pinions,
Rotatably supports the first and second sun gears around the first and second sun gears.
Output to one of the drive shafts of the front and rear wheels.
Composite planetary rig with carrier transmitting to output shaft
Center differential device and multiple friction members
In the configuration in which the mating element is arranged , the friction engagement element includes the first output shaft and the second output shaft.
A first frictional engagement element for engaging and disengaging the power shaft, the first output shaft and by engaging and disengaging the said transfer case, reduction or speed increase gear stage other than the gear position having the automatic transmission And a second frictional engagement element. Wherein said first frictional engagement element has a function of transmitting or blocking power to the other of the front and rear wheels of the drive shaft in the case of four-wheel drive vehicle, the first output shaft the third multi-automatic transmission with a vehicle according to claim 1, frictional engagement element, characterized in that it is mounted in variably controlling the torque distribution between the front and rear wheels in the case of four-wheel drive vehicle.