JP2007168653A - Front/rear wheel driving force distribution device for four-wheel drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a front/rear wheel driving force distribution device capable of obtaining a multi-purpose drive method without largely changing a transfer structure. <P>SOLUTION: A front planetary gear 24 in which a second sun gear 24S2 continues to a drive pinion shaft 6 and a rear/front planetary gear 25 in which a forth sun gear 25S4 continues to a rear drive shaft 10 are provided at a reduction drive shaft 5 of a transfer device 9. Besides, this device has clutches 26, 27 which are engaged respective planetary carriers 241, 251 of the planetary gears 24, 25 with the reduction drive shaft at free/slip/engaging positions, brake clutches 29, 30 which are engaged the planetary gears 241, 251 with a casing 28 in free/slip/engaging positions, and a control section 31 independently operating and controlling the clutches 26, 27, and the brake clutches 29, 30 corresponding to a traveling condition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a front and rear wheel driving force distribution device for a four-wheel drive vehicle.

  Conventionally, a front and rear wheel driving force distribution device (4WD transfer device) of a four-wheel drive vehicle (4WD vehicle) is provided at the rear of the automatic transmission, and an appropriate driving torque is applied to the front and rear wheels by an electronically controlled clutch according to the traveling state. A torque split method (for example, refer to Patent Document 1) that distributes and actively controls four wheels, and a torque distribution near the rear wheel set by a compound planetary gear type center differential device (center differential) is a hydraulic multi-plate type. There is an inequality & variable torque distribution electronic control 4WD system that continuously and variably controls the direct connection 4WD by differential limitation of a differential limiter (LSD) (see, for example, Patent Document 2).

  However, the above-described front and rear wheel driving force distribution device for a conventional four-wheel drive vehicle is a one-mechanism and one-function type that distributes the driving torque that has passed through the automatic transmission to the front and rear wheels according to the running state. is there. For this reason, if a multi-functional drive system is to be provided in order to increase the product value, a mechanism different from the front and rear wheel drive force distribution device must be incorporated into the existing power train system, and the power train system is reviewed. Problems such as cost increase and weight increase occur.

JP 2000-335272 A Japanese Patent No. 2528003

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and a multi-function drive system can be obtained with one mechanism without significantly changing the transfer structure. An object of the present invention is to provide a front-rear wheel driving force distribution device for a four-wheel drive vehicle capable of achieving the above.

  In order to achieve the above object, a first invention provides a front-rear wheel driving force distribution device for a four-wheel drive vehicle having a function of distributing torque generated by an automatic transmission to front and rear wheels according to a traveling state. A front planetary gear and a rear planetary gear, in which a plurality of pinion gears that mesh with a plurality of sun gears are integrally formed in parallel, are provided in parallel on an input shaft of the wheel driving force distribution device, and the front planetary gear and the rear planetary gear include a plurality of A plurality of pinion gears that mesh with the sun gear are integrally formed in parallel, and the first sun gear of the front planetary gear and the third sun gear of the rear planetary gear provided on the input shaft, and the driving torque is transmitted to the front wheel side driving force. A second sun gear of the front planetary gear that outputs to the shaft, and the driving torque is driven on the rear wheel side. A first sun gear of the rear planetary gear output to the transmission shaft, a first planetary carrier of the front planetary gear and the input shaft which can freely, slip and fasten; and a second planetary of the rear planetary gear. Second fastening means for enabling free, slip and fastening of the carrier and the input shaft; third fastening means for enabling free, slip and fastening of the first planetary carrier and the casing of the front planetary gear; and A fourth fastening means for allowing the second planetary carrier of the rear planetary gear and the casing to be free, slipped and fastened, and a control means for individually controlling the first to fourth fastening means according to the running state; Are characterized by comprising the above.

  In order to achieve the above object, according to a second invention, in the first invention, the front planetary gear and the rear planetary gear have different gear ratios.

  To achieve the above object, according to a third invention, in the second invention, the gear ratio is set such that the front planetary gear acts as a speed reduction planetary and the rear planetary gear acts as a speed-up planetary. To do.

  According to the first to third inventions, when the control means individually controls the first and second fastening means and the third and fourth fastening means according to the running state, the front and rear wheel driving force distribution device In addition to the function of performing torque distribution control within the range of direct connection 4WD to front wheel 99: rear wheel 1 to front wheel 1: rear wheel 99, an ultra-low speed gear having a gear ratio that is further lower than the first gear ratio of the automatic transmission. Front wheel 100: A function that emphasizes front wheel drive that distributes torque to the rear wheel 0. Although the wheel speed is basically 4WD, the rear wheel speed is increased more than the front wheel speed. A function that greatly improves the turning performance by trying to come out, front wheel 0: a function that emphasizes rear wheel drive that distributes torque to the rear wheel 100, front wheel 100: distributes torque to the rear wheel 0, and an automatic transmission Multi-stage function, front wheel 0: torque on rear wheel 100 Carry out a, and the automatic transmission device exhibits the function of multistage. Accordingly, the front-rear wheel driving force distribution device can be provided with a multi-functional drive system at a low cost in order to increase the commercial value without causing problems such as a review of the powertrain system, an increase in cost, and an increase in weight. Moreover, the radial direction can be configured very compactly, the floor tunnel of the current product can be used as it is, and the parts can be shared with other models, and a layout with various gear ratios is possible. As a result, it is possible to provide a front-and-rear wheel driving force distribution device for a four-wheel drive vehicle that can obtain a multi-function drive system with one mechanism without significantly changing the transfer structure.

  In order to achieve the above object, according to a fourth aspect of the invention, in the configuration of any one of the first to third aspects, the distance between the planetary cores of the front planetary gear is greater than the distance between the planetary cores of the rear planetary gear. Features.

  According to the fourth aspect of the present invention, the distance between the planetary cores of the front planetary gear is larger than that between the planetary cores of the rear planetary gear, so the load on the input shaft of the front and rear wheel driving force distribution device from the rear planetary gear is reduced. Thus, in addition to the effects of the first to third inventions, even if the front planetary gear and the rear planetary gear are provided in parallel on the input shaft of the front and rear wheel driving force distribution device, the input shaft of the front and rear wheel driving force distribution device There is no need to significantly change the structure, and the input shaft of the existing front and rear wheel driving force distribution device can be used almost as it is.

  The front planetary gear with the second sun gear connected to the front wheel side driving force transmission shaft as the front wheel output element on the input shaft of the front and rear wheel driving force distribution device, and the fourth sun gear as the rear wheel output element connected to the rear wheel side driving force transmission shaft A rear planetary gear is provided in parallel. Further, first and second fastening means for allowing the first and second planetary carriers of the front planetary gear and the rear planetary gear and the input shaft to be free, slipped and fastened, and first and second of the front planetary gear and the rear planetary gear. The third and fourth fastening means for allowing the planetary carrier to be free, slipped and fastened to the casing, and the first and second fastening means and the third and fourth fastening means are individually set according to the traveling state. Control means for controlling operation is provided. As a result, the front and rear wheel driving force distribution device has the function of distributing the driving torque passed through the automatic transmission to the front and rear wheels according to the running state, and the driving torque passed through the automatic transmission is changed to the front and rear wheels according to the running state. A plurality of functions different from the function of distributing torque can be provided. As a result, it is possible to obtain a multi-functional drive system with a single mechanism without significantly changing the transfer structure.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
1 is a cross-sectional view of a 4WD system in which a front and rear wheel driving force distribution device according to this embodiment is incorporated, FIG. 2 is a cross-sectional view of the front and rear wheel driving force distribution device in the same example, and FIG. 3 is a skeleton of FIG. 4 and 4 are schematic diagrams for explaining the operation of the front planetary gear and the rear planetary gear.

  First, a 4WD system in which the front and rear wheel driving force distribution device of the present invention is incorporated will be described. As shown in FIGS. 1 to 3, the power train 100 of the 4WD system includes a torque converter 1, an input shaft 2 as a transmission input shaft, an oil pump 3, an automatic transmission 4, and an output shaft of the automatic transmission 4. Reduction drive shaft 5, drive pinion shaft 6 as front wheel drive force transmission shaft, control valve body 7, front differential gear 8, transfer device 9 as front and rear wheel drive force distribution device, rear as rear wheel drive force transmission shaft A drive shaft 10 is provided.

  As shown in FIG. 1, the torque converter 1 includes a drive-side impeller 11 connected to a crankshaft of an engine, and a cover connected to the impeller 11 and connected to an input shaft 2 of the automatic transmission 4. A driving-side turbine 12 and a stator 13 that rectifies fluid (ATF) flowing between the impeller 11 and the turbine 12 are provided. When the impeller 11 rotates in the fluid, the turbine 12 rotates, and the driving torque output from the engine is amplified and transmitted to the input shaft 2. Further, an oil pump 3 that generates hydraulic pressure is connected to the impeller 11 via a pump drive shaft 14. When the hydraulic pressure from the hydraulic pump 3 is supplied to the lockup clutch 15 by electronic control, the crankshaft and the input shaft 2 are mechanically directly connected.

As shown in FIGS. 1 and 3, the automatic transmission 4 includes two sets of simple planetary gears (front planetary gear 16 and rear planetary gear 17), and three sets of multi-plate clutches (high clutch 18, low clutch 19, reverse clutch 20). Two sets of multi-plate brakes (2 & 4 brake 21, low & reverse brake 22) and a low one-way clutch 23 are provided. Then, as shown in Table 1, these multi-plate clutches 18, 19, 23, and brakes 21 and 22 are engaged and released to perform four forward speeds and one reverse speed.
Table 1 shows an example of the shift position and the operation of each clutch and brake in the automatic transmission 4.

  That is, at the time of first-speed acceleration in the D, 3, and 2 ranges, as shown in FIG. 3, the low clutch 19 is engaged and the front planetary carrier 161 and the rear internal gear 17RR are connected. Further, the low one-way clutch 23 is operated to prevent the rear internal gear 17RR from rotating in the reverse direction. Accordingly, the drive torque is transmitted to the input shaft 2, the rear sun gear 17 SR, the rear pinion gear 17 CR, the rear planetary carrier 171, and the reduction drive shaft 5.

  At the time of the second speed acceleration in the D, 3, 2 range, the low clutch 19 is engaged, the front planetary carrier 161 and the rear internal gear 17RR are connected, the 2 & 4 brake 21 is operated, and the front sun gear 16SF is operated. The rear internal gear 17RR is rotated forward through the front planetary carrier 161 and the low clutch 19 connected to the front planetary carrier 161 to increase the speed from the first speed. Thereby, the drive torque is transmitted to the input shaft 2, the rear sun gear 17SR, the rear pinion gear 17CR, the rear planetary carrier 171, and the reduction drive shaft 5, and the input shaft 2, the rear sun gear 17SR, the rear pinion gear 17CR, the rear planetary carrier 171, the front It is transmitted to the internal gear 16RF, the front pinion gear 16CF, the front planetary carrier 161, the low clutch 19, and the rear internal gear 17RR.

  D During the acceleration of the third speed in the third range, the high clutch 18 is engaged, the front planetary carrier 161 and the rear internal gear 17RR are connected, and the low clutch 19 is operated so that the front planetary carrier 161 and the rear The internal gear 17RR is connected. Thus, the drive torque is transmitted to the input shaft 2, the high clutch 18, the front planetary carrier 161, the low clutch 19, and the rear internal gear 17RR, and is also transmitted from the input shaft 2 to the rear sun gear 17SR, so that the rear pinion gear 17CR, It is transmitted to the rear planetary carrier 171 and the reduction drive shaft 5.

  When accelerating at the fourth speed in the D range, the high clutch 18 is engaged, the front planetary carrier 161 and the rear internal gear 17RR are connected, and the 2 & 4 brake 21 is operated to fix the front sun gear 16SF. As a result, the drive torque is transmitted to the input shaft 2, the high clutch 18, the front planetary carrier 161, the front pinion gear 16CF, the front internal gear 16RF, and the reduction drive shaft 5.

  During coasting at the first speed (coasting), the rear internal gear 17RR rotates in the forward direction, so the low one-way clutch 23 becomes free and idles, and the reverse drive torque is not transmitted, so that the engine brake operates. do not do. Further, during coasting at the 2nd to 4th speed, the reverse driving torque is transmitted to the engine and the engine brake acts because the driving force is not transmitted via the low one-way clutch 23.

  In the R range, the reverse clutch 20 is engaged and the low & reverse brake 22 is operated to fix the front planetary carrier 161. As a result, the drive torque is transmitted from the input shaft 2 to the reverse clutch 20, the front sun gear 16SF (forward rotation), the front pinion gear 16CF, the front internal gear 16RF (deceleration and reverse rotation), and the reduction drive shaft 5.

  Then, the drive torque transmitted to the reduction drive shaft 5 is input to a transfer device 9 provided integrally behind the automatic transmission 4.

  As shown in FIGS. 1 to 3, the transfer device 9 includes a front planetary gear in which an input element is provided in parallel with a reduction drive shaft 5 as an input shaft of the transfer device 9, and a front wheel output element is connected to the drive pinion shaft 6. 24, a rear planetary gear 25 whose rear wheel output element is connected to the rear drive shaft 10, and first and second planetary carriers 241 and 251 of the front planetary gear and rear planetary gears 24, 25 and the reduction drive shaft 5 are free, slipped, and Front and rear LSD clutches 26 and 27 and first and second planetary carriers 241 and 251 of the front planetary gear 24 and the rear planetary gear 25 are free and fitted to the casing 28 as first and second fastening means that can be fastened. The front and rear vectoring brake clutches 29, 30 as the third and fourth fastening means that can be engaged and fastened, the front and rear LSD clutches 26, 27, and the front and rear vectoring brake clutches 29, 30 are run. And a control unit 31 as a control unit that individually controls the operation according to the state.

  More specifically, the front planetary gear 24 is integrally provided in parallel to the first sun gear 24S1 fixed to the reduction drive shaft 5, the first pinion gear 24C1 meshing with the first sun gear 24S1, and the first pinion gear 24C1. The second pinion gear 24C2, the first planetary carrier 241 that rotatably supports the first and second pinion gears 24C1 and 24C2, and the second sun gear 24S2 that meshes with the second pinion gear 24C2 and is an output element on the front wheel side. It is prepared for.

  Further, the second sun gear 24S2 is fixed to the rear end shaft portion of the reduction drive gear 32 supported on the outer peripheral surface of the reduction drive shaft 5 so as to be relatively rotatable. The front end portion of the reduction drive gear 32 is meshed with the driven gear 33 at the rear portion of the drive pinion shaft 6 disposed in parallel to the lower side of the reduction drive shaft 5, whereby the second sun gear 24S2 is connected to the reduction drive gear 32, The drive pinion shaft 6 is continued through a reduction driven gear 33. As a result, the drive torque transmitted to the second sun gear 24S2 is transmitted to the drive pinion shaft 6 via the reduction drive gear 32 and the reduction driven gear 33.

  The drive torque transmitted to the drive pinion shaft 6 is transmitted to the front differential gear 8 through a hypoid gear 34 provided at the front portion of the drive pinion shaft 6. Below the drive pinion shaft 6, a control valve body 7 for supplying and discharging hydraulic oil to each of the clutches 15, 18 to 20 and 23 and the brakes 21 and 22 is disposed.

Between the first planetary carrier 241 and the reduction drive shaft 5, a hydraulic multi-plate type front LSD clutch 26 that allows the first planetary carrier 241 and the reduction drive shaft 5 to be freely slipped and fastened is provided on the front planetary gear 24. It is provided in parallel on the rear side.
Further, between the first planetary carrier 241 and the casing 28 in the radial direction of the front LSD clutch 26, a hydraulic multi-plate front vector that allows the first planetary carrier 241 to be freely slipped and fastened to the casing 28. A ring brake clutch 29 is provided.
The front LSD clutch 26 and the front vectoring brake clutch 29 are individually controlled by the control unit 31 according to the running state.

The rear planetary gear 25 is provided in parallel with the rear side of the front planetary gear 24, and includes a third sun gear 25S3 fixed to the reduction drive shaft 5, a third pinion gear 25C3 meshing with the third sun gear 25S3, and the first planetary gear 25C3. A fourth pinion gear 25C4 integrally provided in parallel with the three-pinion gear 25C3, a second planetary carrier 251 that rotatably supports the third and fourth pinion gears 25C3 and 25C4, and a fourth pinion gear 25C4 and the rear And a fourth sun gear 25S4 which is an output element on the wheel side.
Here, the rotating shaft 51 that rotates together with the reduction drive shaft 5 is also regarded as a part of the reduction drive shaft 5.

  The fourth sun gear 25S4 is fixed to the front end shaft portion of the rear drive shaft 10 that is disposed behind the reduction drive shaft 5 so as to be on the same axis as the reduction drive shaft 5. As a result, the drive torque transmitted to the fourth sun gear 25S4 is transmitted to the rear drive shaft 10.

Further, between the second planetary carrier 251 and the reduction drive shaft 5, a hydraulic multi-plate type rear LSD clutch 27 that allows the second planetary carrier 251 and the reduction drive shaft 5 to be freely slipped and fastened is a rear planetary gear. 25 are provided in parallel on the front side.
Further, between the second planetary carrier 251 and the casing 28 on the circumference of the rear LSD clutch 27, a hydraulic multi-plate rear vector that allows the second planetary carrier 251 to be freely slipped and fastened to the casing 28. A ring brake clutch 30 is provided.
The rear LSD clutch 27 and the rear vectoring brake clutch 30 are individually controlled by the control unit 31 according to the running state.

  As shown in FIG. 4, the front planetary gear 24 and the rear planetary gear 25 are different from each other in the number of teeth Zfs1 to Zrs2 and the gear ratio so that the front planetary gear 24 acts as a speed reduction planetary and the rear planetary gear 25 acts as a speed-up planetary. Have a speed ratio.

  Further, the distance between the planetary cores of the front planetary gear 24, that is, the distance from the rotation center of the first sun gear 24 S 1 (or the second sun gear 24 S 2) to the planetary rotation center is greater than that between the planetary cores of the rear planetary gear 25. Is set. As a result, the load applied to the rear portion of the reduction drive shaft 5 from the rear planetary gear 25 is reduced. Even if the front and rear planetary gears 24 and 25 are provided in parallel on the reduction drive shaft 5, the structure of the reduction drive shaft 5 is greatly increased. There is no need to change.

  As shown in FIG. 1, the control unit 31 includes a transfer duty solenoid 35 as a hydraulic pressure generator for clutch control, a transfer control valve 36 as a control valve, and an ECU 37 as an electronic control unit. Has been.

  In addition to the turbine sensor 38, the front wheel rotation sensor 39, and the rear wheel rotation sensor 40, the ECU 37 includes various sensors such as a throttle opening sensor, an ATF oil temperature sensor, a range signal, and an ABS signal (not shown) and detection output from a switch. Based on the value and the output value, an optimum drive mode corresponding to the running state is selected from a plurality of drive modes stored and stored in advance, and the front and rear LSD clutches 26 and 27, front and rear are selected according to the selected drive mode. The rear vectoring brake clutches 29 and 30 are individually controlled to operate.

  That is, the ECU 37 controls the duty of the transfer duty solenoid 35 according to the selected drive mode, and adjusts the pilot pressure to the transfer duty pressure. This transfer duty pressure acts on the transfer control valve 36. A line pressure is guided to the transfer control valve 36, and the line pressure is adjusted to a transfer clutch pressure by the action of the transfer duty pressure. The front and rear LSD clutches 26 and 27 and the front and rear vectoring brake clutches 29 and 30 can be individually controlled by the transfer clutch pressure.

Here, various drive modes will be described.
The drive modes stored and stored in the ECU 37 are a four-wheel drive mode, a dual range-Low mode, a rear vectoring mode, a dual range-Hi mode, an FF5A / T mode, and an FR5A / T mode.

The four-wheel drive mode (4WD mode) is a normal 4WD mode in which drive torque is distributed between the front and rear wheels.
When this four-wheel drive mode is selected, the front LSD clutch 26 of the front planetary gear 24 is fastened, the first planetary carrier 241 and the reduction drive shaft 5 are fixed, and the front vectoring brake clutch 29 is free (completely) Liberation). Further, the rear LSD clutch 27 of the rear planetary gear 25 is engaged to fix the second planetary carrier 251 and the reduction drive shaft 5 and to make the rear vectoring brake clutch 30 free.
In such a vehicle situation, as shown in FIG. 4, when the rotational speed N1 of the reduction drive shaft 5 is 1000, the rotational speed N2 of the first planetary carrier 241 is 1000, and the rotational speed N3 of the planetary carrier 251 is. = 1000, the rotational speed N4 of the reduction drive gear 32 is 1000, and the rotational speed N5 of the rear drive shaft 10 is 1000, and the driving torque is distributed to the front and rear wheels according to a certain ratio (front wheel 50: rear wheel 50).
Further, in this state, when the front and rear LSD clutches 26 and 27 are slip-controlled (differential control), the drive torque distribution (vectoring amount) is within the range of front wheel 99: rear wheel 1 to front wheel 1: rear wheel 99. Change. Thereby, the transfer device 9 is optimal in any road condition by performing torque distribution control (within the range from the direct connection 4WD to the front wheel 99: rear wheel 1 to the front wheel 1: rear wheel 99) according to the traveling state. Exhibits a function that ensures driving performance.

The dual range-Low mode is a front wheel drive mode with an ultra-low speed gear that is selected when a high driving force is required, particularly when the road surface μ is capable of climbing even on a steep asphalt uphill road or in a front wheel drive state.
When the dual range-Low mode is selected, the front LSD clutch 26 of the front planetary gear 24 is released and the front vectoring brake clutch 29 is engaged to fix the first planetary carrier 241 and the casing 28. Further, the rear LSD clutch 27 of the rear planetary gear 25 is made free, and the rear vectoring brake clutch 30 is also made free.
In such a vehicle situation, as shown in FIG. 4, the number of teeth of each gear of the front planetary gear 24 and the rear planetary gear 25 is set as shown in the table, and the rotation speed N1 of the reduction drive shaft 5 is 1000. As a result, the rotational speed N2 of the first planetary carrier 241 is 1000, the rotational speed N3 of the second planetary carrier 251 is 0, the rotational speed N4 of the reduction drive gear 32 is 636, and the rotational speed N5 of the rear drive shaft 10 is 0. The front planetary gear 24 is a reduction planetary gear having a gear ratio of 1.571 and a speed ratio of 0.636, and the driving torque is distributed only to the front wheels.
As a result, as shown in Table 2, the transfer device 9 functions as an ultra-low speed gear with a gear ratio of 4.375, which is further lower than the low gear (first gear) gear ratio of 2.785 of the automatic transmission 4, and the rear wheel The driving torque of the front wheel is set to 0, and the driving torque of the front wheels is set to 100, so that high driving force is exerted by setting the emphasis on front wheel driving. The climbing ability in case is improved.

The rear vectoring mode is a drive mode that is selected when the turning performance on a winding road or the like and the lane changeability on an expressway or the like are easily improved.
When the rear vectoring mode is selected, the front LSD clutch 26 of the front planetary gear 24 is engaged, the first planetary carrier 241 and the reduction drive shaft 5 are fixed, and the front vectoring brake clutch 29 is made free. Further, the rear LSD clutch 27 of the rear planetary gear 25 is released, and the rear vectoring brake clutch 30 is engaged to fix the second planetary carrier 251 and the casing 28.
In such a vehicle situation, as shown in FIG. 4, assuming that the rotational speed N1 of the reduction drive shaft 5 is 1000, the rotational speed N2 of the first planetary carrier 241 is 1000 and the rotational speed of the second planetary carrier 251 is. The number N3 = 1571, the speed N4 = 1000 of the reduction drive gear 32, and the speed N5 = 1571 of the rear drive shaft 10 are obtained, and the rear planetary gear 25 increases the speed on the rear wheel side more than the speed on the front wheel side. The speed increasing planetary gear has a gear ratio of 0.636 and a speed ratio of 1.571.
As a result, the transfer device 9 exhibits a function of greatly improving the turning performance by increasing the number of rotations on the rear wheel side to increase the number of rotations on the rear wheel side relative to the number of rotations on the front wheel side so as to exit the rear wheel forward. In this case, 4WD is basically used, and traction is also connected to the front wheels, so that stable running performance is always exhibited, and inadvertent spin due to changes in vehicle behavior is avoided.

The dual range-Hi mode is a rear wheel drive mode that is used when it is desired to further improve the turning performance than the rear vectoring mode.
When the dual range-Hi mode is selected, the front LSD clutch 26 of the front planetary gear 24 is released and the front vectoring brake clutch 29 is also released. Further, the rear LSD clutch 27 of the rear planetary gear 25 is made free, and the rear vectoring brake clutch 30 is fastened to fix the planetary carrier 251 and the casing 28.
In such a vehicle situation, as shown in FIG. 4, if the rotation speed N1 of the reduction drive shaft 5 is 1000, the rotation speed N2 of the first planetary carrier 241 is 0 and the rotation of the second planetary carrier 251 is. The number N3 = 1571, the rotational speed N4 = 0 of the reduction drive gear 32, and the rotational speed N5 = 1571 of the rear drive shaft 10 are obtained. The rear planetary gear 25 has a gear ratio 0.636 for increasing the rotational speed on the rear wheel side. The speed increasing planetary gear has a speed ratio of 1.571, and the driving torque is distributed only to the rear wheels.
As a result, the transfer device 9 is set to focus on rear wheel drive in which the front and rear drive torque is distributed to the front wheel 0: rear wheel 100, so turning by reducing the understeer at the corners and ensuring the rear wheel traction. Demonstrates the ability to greatly improve performance.

The FF5A / T mode is a drive mode that is selected when fuel consumption is improved and stable traveling is performed in the front wheel drive state.
When the FF5A / T mode is selected, the vehicle starts with the above-described dual range-low mode ultra-low speed gear ratio (4.375). When the vehicle starts, the front LSD clutch 26 of the front planetary gear 24 is engaged to fix the first planetary carrier 241 and the reduction drive shaft 5 while the automatic transmission 4 shifts from the first speed to the second speed. The front vectoring brake clutch 29 is free. Further, the rear LSD clutch 27 of the rear planetary gear 25 is made free, and the rear vectoring brake clutch 30 is also made free. As a result, the gear ratio is switched to the gear ratio of the normal automatic transmission device 4.
In such a vehicle situation, as shown in FIG. 4, assuming that the rotation speed N1 of the reduction drive shaft 5 is 1000, the rotation speed N2 of the first planetary carrier 241 is 0 and the rotation speed N3 of the planetary carrier 251 is = 0, the rotational speed N4 of the reduction drive gear 32 is 1000, and the rotational speed N5 of the rear drive shaft 10 is 0, and the driving force is transmitted only to the front wheels by the front planetary gear 24.
Thereby, as shown in the upper two columns of Table 2, the transfer device 9 sets the gear ratio 4.375, which is lower than the gear ratio 2.785 of the low gear (first gear) of the automatic transmission 4 to the first gear. The first speed (gear ratio 2.785) of the automatic transmission 4 is 2nd speed, 2nd speed (gear ratio 1.545) is 3rd speed, 3rd speed (gear ratio 1.000) is 4th speed, 4th speed (gear ratio). 0.694) is made to function as 5th speed to improve fuel efficiency and achieve stable driving, and the driving torque of the rear wheels is set to 0, so that the driving torque of the front wheels is set to 100 and high driving is set by emphasizing front wheel driving. Demonstrate power.
Table 2 shows an example of the operation of each clutch and brake in the transfer device 9. The upper 2 columns are for the FF5A / T mode described above, and the lower 2 columns are for the FR5A / T mode described later.

The FR5A / T mode is a drive mode selected when sportiness is desired in the rear wheel drive state.
When the FR5A / T mode is selected, the front LSD clutch 26 of the front planetary gear 24 is released and the front vectoring brake clutch 29 is also released when starting. Further, the rear LSD clutch 27 of the rear planetary gear 25 is engaged to fix the second planetary carrier 251 and the reduction drive shaft 5 and to make the rear vectoring brake clutch 30 free.
In such a vehicle situation, as shown in FIG. 4, if the rotation speed N1 of the reduction drive shaft 5 is 1000, the rotation speed N2 of the first planetary carrier 241 is 0 and the rotation of the second planetary carrier 251 is. The number N3 = 0, the rotational speed N4 = 0 of the reduction drive gear 32, and the rotational speed N5 = 1000 of the rear drive shaft 10 are obtained, and the driving force is transmitted only to the front wheel side by the rear planetary gear 25.
When the automatic transmission 4 shifts to the fourth speed, the rear LSD clutch 27 of the rear planetary gear 25 is released and the rear vectoring brake clutch 30 is engaged to fix the second planetary carrier 251 and the casing 28. Then, the rear planetary gear 25 becomes a speed increasing planetary gear having a gear ratio of 0.636 and a speed ratio of 1.571 for increasing the number of rotations on the rear wheel side.
As a result, as shown in the lower two columns of Table 2, the transfer device 9 adds the fourth speed to the fifth gear ratio of 0.441 in addition to the fourth speed of the automatic transmission device 4 (gear ratio 0.694). Since it functions as a speed, the sportiness (power performance) of the FR drive by A / T multi-stage is improved.

  Although the ECU 37 is configured to store and store a plurality of drive modes in advance, the present invention is not limited to this, and a drive mode changeover switch for selecting one of the plurality of drive modes described above is provided. May be. The ECU 37 can be configured to operate according to the drive mode changeover switch.

  As described above, according to the present invention, when the control unit 31 individually controls the operation of the front LSD clutch 26, the rear LSD clutch 27, the front vectoring brake clutch 29, and the rear vectoring brake clutch 30 according to the traveling state. In addition to the function of performing torque distribution control within the range from the direct connection 4WD to the front wheel 99: rear wheel 1 to front wheel 1: rear wheel 99, the transfer device 9 is a gear that is further lower than the first-speed gear ratio of the automatic transmission 4. It functions as an ultra-low speed gear, and the front wheel 100: a function that emphasizes front wheel drive that distributes torque to the rear wheel 0. Although it is basically 4WD, the rotation speed on the rear wheel side is increased more than the rotation speed on the front wheel side. A function that greatly improves the turning performance by trying to put the rear wheel forward, a function that emphasizes the rear wheel drive that distributes torque to the front wheel 0: rear wheel 100, and the front wheel 10 : Perform torque distribution to the rear wheels 0, and the automatic transmission 4 the function of multistage, front 0: perform torque distribution to the rear wheels 100, and an automatic transmission 4 exhibits the function of multistage. Accordingly, the transfer device 4 can be provided with a multi-functional drive system at a low cost in order to increase the commercial value without causing problems such as a review of the 4WD powertrain 100, an increase in cost, and an increase in weight. Moreover, the radial direction can be configured very compactly, the floor tunnel of the current product can be used as it is, and the parts can be shared with other models, and a layout with various gear ratios is possible. As a result, it is possible to provide a front-and-rear wheel driving force distribution device for a four-wheel drive vehicle that can obtain a multi-function drive system with one mechanism without significantly changing the transfer structure.

  In addition, according to the present invention, the distance between the planetary cores of the front planetary gear 24 is larger than the distance between the planetary cores of the rear planetary gear 25, so the load applied to the reduction drive shaft 5 from the rear planetary gear 25 is reduced. Accordingly, even if the front planetary gear 24 and the rear planetary gear 25 are provided in parallel to the reduction drive shaft 5 as the input shaft of the transfer device 9, it is not necessary to significantly change the structure of the reduction drive shaft 5, and the existing reduction drive The shaft 5 can be used almost as it is.

It is sectional drawing of the 4WD system in which the front-and-rear wheel driving force distribution device concerning this embodiment was incorporated. It is sectional drawing of the front-and-rear wheel drive force distribution apparatus in the example. FIG. 2 is a skeleton diagram of FIG. 1. It is a schematic diagram for demonstrating the effect | action of a front planetary gear and a rear planetary gear.

Explanation of symbols

4 Automatic transmission 5 Reduction drive shaft (input shaft of front and rear wheel driving force distribution device)
6 Drive pinion shaft (front wheel drive force transmission shaft)
9 Transfer device (front and rear wheel drive force distribution device)
10 rear drive shaft 24 front planetary gear 241 first planetary carrier 24C1 first pinion gear 24C2 second pinion gear 24S1 first sun gear 24S2 second sun gear 25 rear planetary gear 251 second planetary carrier 25C3 third pinion gear 25C4 fourth pinion gear 25S3 third sun gear 25S3 third sun gear 25S3 4 Sun gear 26 Front LSD clutch (first fastening means)
27 Rear LSD clutch (second fastening means)
28 Casing 29 Front vectoring brake clutch (third engaging means)
30 Rear vectoring brake clutch (fourth engagement means)
31 Control part (control means)
37 ECU
100 4WD system powertrain

Claims (4)

In a front-rear wheel driving force distribution device for a four-wheel drive vehicle having a function of distributing torque to the front and rear wheels according to the running state through the automatic transmission,
The front and rear wheel driving force distribution device is:
A front planetary gear and a rear planetary gear in which a plurality of pinion gears meshing with a plurality of sun gears are integrally formed in parallel are provided in parallel on the input shaft of the front and rear wheel driving force distribution device,
A first sun gear of the front planetary gear provided on the input shaft and a third sun gear of the rear planetary gear;
A second sun gear of the front planetary gear that outputs the driving torque to a front wheel side driving force transmission shaft;
A fourth sun gear of the rear planetary gear that outputs the driving torque to a rear wheel side driving force transmission shaft;
First fastening means for allowing free, slipping and fastening of the first planetary carrier of the front planetary gear and the input shaft;
Second fastening means for allowing free, slipping and fastening of the second planetary carrier of the rear planetary gear and the input shaft;
Third fastening means for allowing the first planetary carrier and the casing of the front planetary gear to be free, slipped and fastened;
A fourth fastening means for allowing the second planetary carrier of the rear planetary gear and the casing to be free and fastened;
Control means for individually controlling the operation of the first to fourth fastening means according to the traveling state;
A front-and-rear wheel driving force distribution device for a four-wheel drive vehicle, comprising:   The front and rear wheel driving force distribution device for a four-wheel drive vehicle according to claim 1, wherein the front planetary gear and the rear planetary gear have different gear ratios.   The front-rear wheel driving force distribution device for a four-wheel drive vehicle according to claim 2, wherein the gear ratio is set so that the front planetary gear acts as a speed reduction planetary and the rear planetary gear acts as a speed-up planetary. .   The front-rear wheel driving force distribution device for a four-wheel drive vehicle according to any one of claims 1 to 3, wherein a distance between the planetary cores of the front planetary gear is larger than a distance between the planetary cores of the rear planetary gear. .

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