JPH068738A - Drive device with center differential gear device - Google Patents

Abstract

PURPOSE:To reliably prevent the occurrence of a gear shift shock and blow up of an engine, in constitution wherein a center differential gear function or a boosting and a deceleration function are provided through engagement and disengagement between a clutch and a brake by means of a drive system having a center differential gear device. CONSTITUTION:A center differential gear device 50 is coupled to an automatic transmission 30. The center differential gear device 50 has at least a common drum member provided with a direct clutch 61 and a brake 63 for boosting. Through engagement of the direct clutch 61, a center differential gear function is carried out and through engagement of the brake 63 for boosting, a boosting step is provided. Further, a one-way clutch 70 is arranged to a drum member such that a drive system is properly engaged and disengaged during engagement and disengagement between the clutch 61 and the brake 63.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive unit in a vehicle in which a center differential device is combined with an automatic transmission. More specifically, the center differential device is configured to obtain speed-up and speed-down functions in addition to the center differential function. When it comes to power trains.

[0002]

2. Description of the Related Art Generally, in a drive system of a vehicle equipped with an automatic transmission, the automatic transmission is combined with a speed reducer and a speed increaser,
It is known to increase or decrease the number of gears by combining the gear ratios of both transmissions. In this case, in a gearbox or the like, when releasing one of the brake element and the clutch element and engaging the other to shift gears, the timing of operation of both elements becomes a problem. That is, when the brake element and the clutch element are both engaged, a shift shock is generated due to the locking of the drive system, and conversely, when both are released, the drive system is disconnected and the engine is put into a no-load state and blows up. For this reason, it is necessary to configure the drive system even in a speed increaser or the like so as not to cause a shift shock or engine blow-up.

Conventionally, there has been an application, for example, in Japanese Patent Application No. 3-348205 regarding a combination of an automatic transmission with a center differential device and using this center differential device for a speed increaser. Here, the center differential device is configured as a compound planetary gear type, and this center differential device is configured to be transmitted via a direct clutch, a speed increasing brake, and a transfer clutch of a hydraulic multi-plate clutch device. For example, it is shown that the center differential function is achieved by engaging the direct clutch, and the center differential function is canceled to obtain the speed increasing stage by releasing the direct clutch and engaging the speed increasing brake.

[0004]

By the way, in the above prior art, the output element of the center differential device is configured to be transmitted only through the direct clutch. Therefore, when the clutch is disengaged and the speed increasing brake is engaged to shift to the operation state in which the speed increasing stage is obtained, there is a possibility that a gear shift shock, engine upstroke, etc. may occur.

The present invention has been made in view of this point, and has a structure in which a center differential function or an acceleration or deceleration function is obtained by engaging or disengaging a clutch and a brake in a drive system having a center differential device. The purpose is to reliably prevent gear shift shock and engine blow-up.

[0006]

In order to achieve the above object, the present invention is directed to a center differential device connected to an automatic transmission, and this center differential device engages at least one of a clutch and a brake and releases the other. Therefore, in the drive system configured to have the center differential function or the speed increasing / decelerating functions, the clutch and the brake of the center differential device are provided on the common drum member, and the one-way clutch is attached to this drum member, and when the brake is released. It is provided so that it is automatically integrated and automatically released when the brake is engaged.

[0007]

Based on the above-mentioned structure, the shift power from the automatic transmission is input to the center differential device, and at this time, the brake is released and the clutch is engaged to generate the center differential function. Engagement causes a speed-up or deceleration function to be transmitted. At this time, when shifting from the center differential function to the speed increasing or decelerating function, the clutch is first released and then the brake is engaged, and conversely, when shifting from the speed increasing or decelerating function to the center differential function, , By first releasing the brake and then engaging the clutch, the one-way clutch will cause the drive system to lock or disconnect, making proper disconnection so that there is no shift shock or engine blow-up. Will be done.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. Referring to FIG. 1, a drive system of a four-wheel drive vehicle in which an automatic transmission is combined with a center differential device will be described. First, the transmission case 3 is provided at the rear of the torque converter case 1 and the differential case 2.
Are joined together, the transfer case 4 and the extension case 6 are joined to the rear portion of the transmission case 3, and the oil pan 5 is attached to the lower portion of the transmission case 3.

Reference numeral 10 is an engine. A crankshaft 11 of the engine 10 is connected to a torque converter 13 provided with a lockup clutch 12 inside the torque converter case 1, and an input shaft 14 from the torque converter 13 is connected.
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 the transmission output shaft 15 is coaxially connected to the center differential device 50 inside the transfer case 4.

Inside the transmission case 3, the front drive shaft 1 with respect to the input and output shafts 14 and 15
6 are arranged in parallel, the rear end of the front drive shaft 16 is connected to the center differential device 50 via a pair of reduction gears 17 and 18, and the front end of the front drive shaft 16 is connected to the front differential device 19 inside the differential case 2. It is configured to be transmitted to the front wheels via. On the other hand, the center differential device 5
A hydraulic multi-plate clutch device 60 is provided at the rear of 0,
The rear drive shaft 20 output from the hydraulic multi-plate clutch device 60 is also transmitted to the rear wheels via a propeller shaft 21, a rear differential device 22, and the like.

The automatic transmission 30 has a structure in which four forward gears and one reverse gear are obtained 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 32a of the rear planetary gear 32, and the ring gear 31b of the front planetary gear 31 and the carrier 32c 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 the coupling element 33 that is integral with 1c and the ring gear 32b, and the first one-way clutch 34 and the forward clutch 35 are provided between the coupling element 33 and the case side that is the fixing member. 2 one-way clutch 3
6. A low reverse brake 37 is provided in parallel.
An overrunning clutch 38 is provided as a bypass between the connecting element 33 and the ring gear 32b.

A band brake 40 is provided on the connecting element 39 which is integral with the sun gear 31a, and the band brake 40 is provided.
A high clutch 43 is provided between the connection element 41 integrated with the connection element 41 and the connection element 42 integrated with the carrier 31c. Further, a reverse clutch 44 is provided between the connecting elements 39 and 41.

With the structure of the automatic transmission 30, when the D range is selected, the forward clutch 35 is engaged, and the ring gear 32b is locked together with the connecting element 33 by the action of the one-way clutches 34 and 36, whereby the input shaft 14 is locked. From the sun gear 32a and the carrier 32c to the transmission output shaft 15 with a large gear ratio.
Be fast. Then, when the vehicle speed increases, the sun gear 31a is further locked by the engagement of the band brake 40. Therefore, the carrier 31c and the ring gear 32b form the connecting element 3
3, the forward clutch 35, and the first one-way clutch 34 are rotated to rotate the ring gear 32b more than the first gear.
The power that has been increased by the amount of rotation of is output and the speed is changed to the second speed. Next, the high clutch 43 is engaged to connect the input shaft 14 to the ring gear 32b via the connecting elements 41, 32, the carrier 31c, the connecting element 33, the forward clutch 35, and the first one-way clutch 34. Therefore, the rear planetary gear 32 is integrated, the input shaft 14 and the transmission output shaft 15 are directly connected, and the speed is changed to the third speed.

When the vehicle speed further increases, the sun gear 31a is locked by the engagement of the band brake 40 in addition to the above.
Therefore, in the front planetary gear 31, the ring gear 31b is accelerated by the power input to the carrier 31c by the high clutch 43, and the fourth gear of the overdrive is used.
The speed is changed. On the other hand, when the R range is selected, the reverse clutch 44 is engaged and the sun gear 31a is connected to the input shaft 1
Power of 4 is input. Further, since the carrier 31c is locked together with the coupling element 33 by the engagement of the low reverse clutch 37, the front planetary gear 31 is used to lock the ring gear 31b.
Power with a large gear ratio, which was reversed, is output to reverse speed. Thus, in the automatic transmission 30, four forward gears and one reverse gear 1
It is possible to obtain a gear shift stage.

On the other hand, an oil pump 45 is installed in front of the automatic transmission 30 and is constantly driven by a drive shaft 46 on the pump impeller side of the torque converter 13. A control valve body 47 is accommodated in the oil pan 5 so that oil can be supplied to and discharged from each of the above-mentioned clutches and brakes and selectively engaged.

In FIG. 2, the center differential device 50 and the hydraulic multi-plate clutch device 60 will be described. First, the rear drive shaft 20 is coaxially arranged behind the output shaft 15 via the first and second intermediate shafts 23 and 24. A front wheel side reduction gear 17 is rotatably fitted to the output shaft 15, and a center differential device 50 is provided between the output shaft 15, the reduction gear 17 and the first and second intermediate shafts 23 and 24. It is arranged on the same axis.

The center differential device 50 is composed of a compound planetary gear and has an output shaft 15
The first sun gear 51 and the second intermediate shaft 24
Has a second sun gear 53 formed in. Further, the first and second pinions 52 and 54, which are integrally formed in the axial direction, are rotatably mounted on the pinion shaft 56 mounted on the carrier 55, and the first pinion 52 is attached to the first sun gear 51.
However, the second pinion 54 meshes with the second sun gear 53, and the torque-distributed power is output to the second intermediate shaft 24. On the other hand, the first intermediate shaft 23 is further loosely fitted inside the second intermediate shaft 24, and the first intermediate shaft 23 is attached to the carrier 55 via the connecting member 57 in the gap between the two sun gears 51 and 53. They are integrally spline-coupled to perform a function such as differential limitation. Further, the reduction gear 17 is coupled to the front end of the carrier 55 to output the power of the carrier 55.

This center differential device 50
With the configuration of, the power input to the first sun gear 51 is
It 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 the front and rear wheels are unequal. It has the function of distributing torque. Further, the planetary rotation of the first and second pinions 52 and 54 has a differential function of absorbing a difference in rotation speed between the carrier 55 and the second sun gear 53, which is caused by a difference in turning radius during turning.

Next, the center differential device 5
The function of the zero speed increaser will be described. In this complex planetary gear type center differential device 50, a predetermined speed increasing gear ratio can be obtained by fixing the second intermediate shaft 24. This speed increasing gear ratio is independent or a predetermined speed change step of the automatic transmission 30. The speed is further changed to the fifth speed by the cooperation of. Therefore, for example, the case of using the second speed gear stage will be described. The second speed gear ratio i
2. Due to the speed increasing gear ratio ip of the center differential device 50, the gear ratio i5 of the fifth speed is as follows. i5 = i2 · ip Here, for example, ip = (33-21) /33=0.3 depending on the gear specifications of the center differential device 50.
63, and assuming that the gear ratio of the second speed is 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. .

Explaining the hydraulic multi-plate clutch device 60, drum members 64 and 65 are provided on the second intermediate shaft 24 and the rear drive shaft 20, respectively, and both drum members 6 are provided.
A direct clutch 61 that connects and disconnects the power to the rear wheels is provided between 4 and 65. In addition, a transfer clutch 62 that restricts the differential between the first intermediate shaft 23 and the drum member 65 and variably controls the torque distribution of the front and rear wheels is interposed, and the transfer clutch 62 is provided between the drum member 64 and the case 4 for acceleration. The brake 63 is provided. And these clutches 61, 62
And the speed-increasing brake 63 are overlapped with each other three times and are arranged coaxially.

The clutches 61, 62 and the speed increasing brake 63 are hydraulically controlled by, for example, a dedicated valve body. That is, when the automatic transmission 30 shifts from four forward gears to one reverse gear, the speed-increasing brake 63 is released and the direct clutch 61 is engaged. At this time, the transfer clutch 62 is engaged in accordance with a rear wheel slip or the like. Produces a motion limiting torque. When the vehicle speed exceeds the set value at the fourth speed, the center differential device 50 greatly increases the speed. Therefore, the automatic transmission 30 is controlled to shift from the fourth speed to the second speed, and at the same time, the direct clutch 61 is released. Then, the speed increasing brake 63 is engaged, and at this time, a transfer torque is generated in the transfer clutch 62 according to front wheel slip or the like.

Further, means for smoothly releasing and engaging the direct clutch 61 and the speed increasing brake 63 will be described. The clutch 61 and the brake 63 are provided on a common drum member 64.
In consideration of the fact that the one-way clutch 70 is integrally coupled to the engaging side, the one-way clutch 70 is mounted between the two drum members 64 and 65 in parallel with the direct clutch 61. As shown in FIG. 3, the one-way clutch 70 has two drum members 64,
The sprags 71 are provided so as to be inclined between the drums 65, and only the power transmission from the one drum member 64 to the other drum member 65 is possible. And the direct clutch 61
By releasing one of the speed increasing brake 63 and the other and engaging the other, the one-way clutch is used when upshifting from the fourth speed to the fifth speed or when downshifting from the fifth speed to the fourth speed. The action of 70 is used to mechanically prevent the driveline from locking or disconnecting.

Next, the operation of this embodiment will be described. First, the power of the engine 10 is the torque converter 13,
By inputting to the automatic transmission 30 via the input shaft 14, by operating the two sets of the front planetary gear 31 and the rear planetary gear 32, and selectively engaging the clutches 44, 43, 35, 38, 36, 34 and the brakes 40, 37. , D range is automatically shifted to the first to fourth forward speeds, and reverse speed is selected when the R range is selected. Then, this shift power is input from the transmission output shaft 15 to the first sun gear 51 of the center differential device 50, and torque is distributed. Further, in this case, the direct clutch 61 of the hydraulic multi-plate clutch device 60 is engaged,
The second sun gear 53 of the center differential device 50 is connected to the rear drive shaft 20.

Here, the gear power of the center differential device 50 causes the shifting power to be output to the carrier 55 and the sun gear 53 in an unequally distributed manner. The power of the carrier 55 is the drive power of the reduction drive gear 1.
7, through the reduction driven gear 18, the front drive shaft 16, and the front differential device 19 to the front wheels. The power of the second sun gear 53 is transmitted to the second intermediate shaft 24, the direct clutch 61, and the rear wheels after the rear drive shaft 20. In this case, the one-way clutch 70 arranged in parallel with the direct clutch 61 is also integrated. Power is transmitted by both of these. In this way, the unequal torque is distributed to the front and rear wheels and the four-wheel drive mode is performed with the rear wheels being deviated, and in this torque distribution, oversteering tends to occur, and the turning performance and maneuverability are improved. During this four-wheel drive traveling, the planetary rotation of the first and second pinions 52, 54 of the center differential device 50 absorbs the difference in the rotational speeds of the front and rear wheels generated during the turning, and allows the vehicle to freely turn.

Next, when the vehicle travels on slippery roads, the reference torque distribution is such that the rear wheel is heavily biased, and therefore the rear wheels usually slip first. In this case, the differential limiting torque Tc of the transfer clutch 62 depends on the slip state. Controlled.
Then, between the carrier 55 of the center differential device 50 and the second sun gear 53, another transmission system path formed by the carrier 55, the connecting member 57, the first intermediate shaft 23, and the transfer clutch 62 is formed by bypassing. Torque bypass is performed from the rear wheel side of the rotating second sun gear 53 to the front wheel side of the low rotating carrier 55 in accordance with the differential limiting torque Tc. Therefore, the torque distribution is controlled toward the front wheels to prevent the rear wheels from slipping and improve the 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, and the direct connection type four-wheel drive is performed, so that the load distribution of the front and rear wheels is distributed. The torque distribution is equivalent. By controlling the differential limiting torque Tc in this manner, the torque distribution is variably controlled between the rear wheel bias and the direct coupling type.

On the other hand, if the speed becomes higher than the traveling condition of the fourth speed, the speed increase by the center differential device 50 is significantly increased, so that the automatic transmission 30 is in the state from the fourth speed to the second speed (third speed). The hydraulic pressure is controlled so that the direct clutch 61 is released and the speed increasing brake 63 is engaged at the same time. Therefore, in the center differential device 50, the second sun gear 53 is fixed together with the drum member 64 and the second intermediate shaft 24, and the carrier 55 is rotated at an increased speed. At this time, the drum member 6
Since the one-way clutch 70 is automatically freed by fixing 4 and the power transmission of this path is cut off,
In this way, it functions as a speed-up gear by killing the center differential function.

Therefore, the power of the second speed (or the third speed) of the automatic transmission 30 is changed to the center differential device 50.
Thus, the speed is greatly increased and transmitted to the front wheels after the carrier 55, and the gear is upshifted to the fifth speed, which is the speed increasing stage having a smaller gear ratio than the fourth speed, and is suitable for high speed running. At this time, when the transmission torque Td of the transfer clutch 62 is variably controlled according to the running state or the front wheel slip condition, the torque is also transmitted from the carrier 55 to the rear wheels via the first intermediate shaft 23 and the transfer clutch 62. It Therefore, the front wheel slip is prevented, and similarly, the torque distribution of the front and rear wheels can be controlled so that the vehicle is driven by four wheels.

At the time of upshifting from the fourth speed to the fifth speed, the direct clutch 61 is first controlled to be released so that the one-way clutch 70 keeps the power transmission state from the center differential device 50 to the rear wheels. Secured. Then, the one-way clutch 70 is controlled by controlling the speed-increasing brake 63 to be engaged.
Is changed to the fifth speed while the drive system is changed.

Conversely, at the time of downshifting from the fifth speed to the fourth speed, the speed increasing brake 63 is first released,
The one-way clutch 70 is automatically integrated with the release of the fifth speed, and the drive system enters the fourth speed state. Then, by engaging the direct clutch 61, the power is transmitted by both the direct clutch 61 and the one-way clutch 70 to return to the state in which the center differential function is performed.

Although the embodiments of the present invention have been described above, the same can be applied to the case where the center differential device is used as a speed reducer.

[0032]

As described above, according to the present invention,
In the drive unit with center differential device,
When the center differential is equipped with a center differential clutch and a brake that accelerates or decelerates, the one-way clutch prevents the drive system from locking or disconnecting. It can be surely prevented. Since the drive system is mechanically connected and disconnected by the action of the one-way clutch, timing control of engagement and disengagement of the clutch and brake is not required, and hydraulic control is facilitated.

Since the one-way clutch is mounted between the two drum members arranged coaxially, the structure and the assembling are easy. In the case of the center differential function, since the power is transmitted by both the direct clutch and the one-way clutch, the capacity of the direct clutch can be reduced, and the hydraulic clutch device can be downsized and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing an embodiment of a drive device with a center differential device according to the present invention.

FIG. 2 is a cross-sectional view showing a main part of the embodiment.

FIG. 3 is a sectional view showing a one-way clutch.

[Explanation of symbols]

 30 automatic transmission 50 center differential device 60 hydraulic clutch device 61 direct clutch 62 transfer clutch 63 speed-up brake 70 one-way clutch

Claims (2)

[Claims] 1. A center differential device is connected to an automatic transmission, and this center differential device engages at least one of a clutch and a brake and releases the other, thereby having a center differential function or a speed increasing / decelerating function. In the drive system configured as described above, the clutch and brake of the center differential device are provided on a common drum member, and the one-way clutch is automatically integrated with this drum member when the brake is released, and automatically when the brake is engaged. A drive device with a center differential device, which is provided so as to be free. 2. The drive device with a center differential device according to claim 1, wherein the one-way clutch is provided in parallel with the clutch between two drum members coaxially arranged.