JPS62203828A - Torque transfer controller for four wheel drive vehicle - Google Patents

Abstract

PURPOSE:To make a controller perform control over torque transfer according to clutch hydraulic pressure as well as to optimize the torque transfer to both front and rear wheels with each driving condition, and make improvements in turnability and safety, by installing two sets of planetary gears and two sets of hydraulic clutches in combination in the point midway in a front-rear wheel driving system. CONSTITUTION:Two sets of planetary gears 30 and 35, in the same structure, for center differential gear use are installed in the point midway in a front-rear wheel driving system, and constituted of sun gears 31 and 36, ring gears 32 and 37, pinions 32 and 38 to be engaged with these gears, and carriers 34 and 39. And, the sun gear 31 is connected to a rear wheel shaft 19 via a gear 23 and the sun gear 36 to a front wheel shaft, respectively. Thus, a rotational difference between front and rear wheels is absorbed by planetary rotation of these pinions 33 and 38. And, a hydraulic clutch 40 is connected to an interval between the ring gear 37 and the sun gear 36 and a hydraulic clutch 45 to an interval between a gear 22 and the rear wheel shaft 19 respectively, thus these clutches are installed. Then, a torque transfer signal corresponding to a driving condition is outputted to actuators 55 and 56 from a control unit 54, and hydraulic pressure in these hydraulic clutches 40 and 45 is altered, whereby torque control takes place.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a torque distribution control device for controlling drive torque distribution between front and rear wheels according to driving conditions, road conditions, etc. in a full-time four-wheel drive vehicle equipped with a center differential. This relates to the case where two sets of clutches are used.

[Conventional technology]

Conventionally, with regard to four-wheeled φ rickshaws with rental differentials, as shown in Japanese Unexamined Patent Publication No. 55-72420, for example, there have been some in which a differential gear is used in the center differential device and a hydraulic clutch is provided to limit the operation of the differential gear. .

[Problems to be solved by the invention]

By the way, in the configuration of the prior art described above, since the diameter of the two side gears of the single center differential differential gear is mechanically the same, the torque distribution between the front and rear wheels is always approximately equal. Therefore, it was not possible to actively change the torque distribution. Further, the hydraulic clutch only has a differential lock function that integrally locks the differential gear for emergency escape when one of the front and rear wheels is idling. In a four-wheel drive vehicle, it is known that by changing the torque distribution between the front and rear wheels depending on various driving conditions, performance such as turning performance and stability can be improved in addition to power performance. Therefore, even in full-time systems with a center differential, it is desirable to actively control torque distribution to increase added value. The present invention has been made in view of these points. In a full-time type with a center differential, the torque distribution between the front and rear wheels is controlled depending on the driving conditions, etc., thereby improving turning performance, stability, etc. The object of the present invention is to provide a torque distribution control device for a four-wheel drive vehicle that is capable of controlling the torque distribution of a four-wheel drive vehicle.

[Means to solve the problem]

In order to achieve the above object, the present invention provides two sets of differential gear devices for a center differential in the middle of a drive system for front and rear wheels, connects a transmission output shaft to an input element of the first differential gear device,
a first output element is connected to the rear wheel side, a second output element is connected to an input element of a second differential gear device, the first output element of the second differential gear device is connected to the front wheel side, and a second output element is connected to the front wheel side; output element is connected to the rear wheel side, and the first and second output elements of the second differential gear device are connected to the rear wheel side.
A first hydraulic clutch is provided between the output elements of the first differential gear device, and a second hydraulic clutch is provided between the first output element of the first differential gear device and the second output element of the second differential gear device, And the torques TF and TR of the front and rear wheels are determined by the clutch oil pressure of the second hydraulic clutch, and TF - is TR, TF 1=
The distribution is controlled into three types: FTR, TF>TR. By changing the clutch oil pressure of the first or second hydraulic clutch, the distribution amount is continuously changed in the state of TF<TR or TF>TR.

[For production]

Based on the above configuration, when the first hydraulic clutch is engaged, power is transmitted from the second output element and the first output element of the first differential gear device to the front and rear wheels, and due to the difference in gear diameter, the TF
>TR, and when the second hydraulic clutch is engaged, the first output element of the second differential gear device and the first output element of the first and second differential gear devices are distributed. Power is transmitted from the second output element to the front and rear wheels, and due to the difference in the number of power transmission paths,
Torque is distributed as TF<TR. In this state, all the differential gear devices operate as a center differential, and the torque distribution m is continuously controlled by changing the clutch oil pressure. Further, when both the first and second hydraulic clutches are engaged, the first and second differential gear devices are integrated and differentially locked, and the T
Torque will now be distributed to F #TR. In this way, according to the present invention, it is possible to provide the driving performance of a full-time four-wheel drive vehicle with a center differential, the differential lock function, and the other performance by torque distribution of TF <TR, TF >TR.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. In FIG. 1, there are four wheels according to the present invention! To explain the transmission system of 1111, engine 1. The clutch 2 and the transmission 4914 are arranged vertically in the longitudinal direction of the vehicle body, and the front differential device 16 is assembled and installed inside the transmission case at the lower part between the clutch 2 and the transmission 4, thereby forming a transaxle type. . The transmission 4 is of a constant mesh type, with an output shaft 5 disposed parallel to the input shaft 3, and four sets of mutually meshing wheels 3. Shift gears 6 to 9 are provided, and a synchronization mechanism 10 between gears 6 and 7 is provided. By selectively operating a synchronizing mechanism 11 between gears 8 and 9, each forward gear stage from first speed to fourth speed is obtained. Further, the reverse gear is obtained by meshing the sleeve-side gear 13 of the synchronizing mechanism 10 with the reverse gear gear 12 provided on the input shaft 3 via an idler gear (not shown). The output shaft 5 is a hollow shaft, into which the front drive shaft 14 is inserted, and a drive pinion 15 formed at the front end of the front drive@14 meshes with the crown gear 17 of the front differential device 16 to drive the front wheels. The transmission is configured on the side. Further, the transfer device 1 disposed at the contact portion of the transmission 4
8, the output shaft 5 and the front drive shaft 14 inside the output shaft 5 are arranged coaxially, and the rear drive shaft 19 is arranged above these in parallel. and rear drive shaft 19
Further, the propeller shaft 20. Transmission is configured to the rear wheels via the rear differential device 21. The transf 1 device 18 connects two sets of planetary gear devices 30 and 35 to the front drive shaft 1 for the center differential.
4 on top, 2 on 3! I! and have it. Both planetary gear units 30, 35 have the same configuration, with sun gears 31, 36,
Ring gears 32, 37, binions 33 meshing with them,
38 and Kireliya 34.39. The transmission output shaft 5 is coupled to the carrier 34 of the planetary gear device 30 at the front stage, the sun gear 31 is coupled to the A7 drive shaft 19 via a pair of gears 23, and the ring gear 32 is coupled to the carrier 34 of the planetary gear device 35 at the rear stage. join to. Further, a sun gear 36 of the planetary gear device 35 is connected to the front drive shaft 14, and a ring gear 37 is connected to the rear drive shaft 19 side via a pair of gears 22. Thus, overall the ring gear 32. Power is separately transmitted from the sun gear 36 to the front wheels and similarly from the sun gear 31° and the ring gear AA 37 to the rear wheels, and a 1vI rear wheel rotation difference is absorbed by the planetary rotation of the binions 33 and 38. In addition, two sets of hydraulic clutches 40.45 are used for differential lock and torque distribution control, and the above-mentioned planetary gear system fi3
It has a rear of 0.35. That is, the hydraulic clutch 40 connects the ring gear 37 and the sun gear 36 of the planetary gear device 35.
Between the hub 41. The hydraulic clutch 45 is provided by coupling the drums 42 to each other, and the hydraulic clutch 45 connects the gear 22 on the ring gear 37 side of the planetary gear device 35 and the planetary gear device 30.
between the rear drive @19 on the sun gear 31 side and the hub 4.
G and drum 47 are combined. The hydraulic clutches 40, 45 are engaged or released by clutch oil pressure, and further generate arbitrary clutch torque to make the transmitted torque variable. To explain the torque distribution control system, the vehicle speed sensor 50
．． Rudder angle sensor 51. Acceleration sensor 52. It has manual instruction means 53 and the like, and these signals are input to the control unit 54. The control unit 54 determines medium/low-speed turning and high-speed driving conditions based on sensor signals, determines rough roads such as muddy terrain, stuck, etc. based on signals from the manual instruction means 53, and distributes torque accordingly. Establish. Then, according to the output signal of the control unit 54, the actuator 55.
The clutch hydraulic pressure of the hydraulic clamp 40.45 is changed through the hydraulic clutch 56. Next, the operation of the torque distribution control device configured as described above will be explained. First, power from the transmission 4 is input to the carrier 34 of the planetary gear device 30 at the front stage in the transfer device 18, and is transmitted from the sun gear 31 to the gears 23. Rear drive shaft 1
The signal is transmitted to the subsequent rear wheels from the ring gear 32 to the carrier 39 of the rear gear A7 device 35. Therefore, when one hydraulic clutch 40 is engaged by the control unit 54 at the maximum clutch oil pressure under high-speed driving conditions,
The planetary gear device 35 includes a sun gear 36 and a ring gear 3.
It becomes one by combining with 7. Therefore, the ring gear 32
The power from the fW35. It is transmitted to the front wheels of the front drive@14 and later. Thus, substantially the ring gear 32 of the planetary gear device 30
．． Power is transmitted from the sun gear 31 to the front and rear wheels to provide four-wheel drive, and the planetary rotation of the binion 33 absorbs the difference in rotation between the front and rear wheels to act as a center differential. In this case, due to the difference in gear diameter between the small diameter sun gear 31 and the large diameter ring gear 32, the torque TF of the front and rear wheels is
, TR are distributed to the state where TF>TR as shown in FIG. 2 (f), thereby improving stability. Here, the clutch oil pressure of the hydraulic clutch 40 is reduced and its torque TC
P is decreased as shown in Figure 2). At the same time, if the clutch torque TCR of the hydraulic clutch 45 is increased, the torque transmitted from the planetary gear device 35 to the front wheels is reduced, but the reduced amount is transferred to the planetary gear device 35.
From gear 22. It is applied to the rear wheel side via the hydraulic clutch 45. In this way, as shown in Fig. 2 (2), the front wheel torque T
As F decreases, the rear wheel torque "l" increases, and the amount of distribution between the two continuously changes from a large state to a small state. On the other hand, at medium and low speeds, the control unit 54 now controls the rear wheel torque "l". When the hydraulic clutch 45 engages, the gear 22 on the ring gear 37 side of the planetary gear device 35 engages the rear drive shaft 1.
Combines with 9. Therefore, both planetary gears J30.
Power is transmitted from the 35° gears 31 and 36 to the rear wheels, and only from the sun gear 36 of the planetary gear device 35 to the front wheels, resulting in four-wheel drive. The planetary rotation of the binions 33 and 38 of the two sets of planetary gear devices 130 and 35 and the rotation of the ring gear 32 and carrier 39 act as a center differential. In this case, the sun gears 31. of the two planetary gear devices 30.35. Two systems with ring gear 37 provide cJ to the rear wheels.
By transmitting force, the torque distribution between the front and rear wheels is as shown in Figure 2 (see below).
As shown in parentheses, TF<TR will be established, improving turning performance. Here, the clutch torque TCR of the hydraulic clutch 45 is reduced as shown in parentheses in FIG.
Conversely, if the torque is increased, part of the torque transmitted from the ring gear 37 to the rear wheels will flow toward the front wheels. In this way, as the rear wheel torque TR decreases, the front wheel torque TF increases as shown in parentheses in FIG. 2(2), and the distribution amount of the torques TF and TR changes continuously in the same way as described above. Further, when both hydraulic clutches 40, 45 are engaged together by the control unit 54 when driving on a rough road, in addition to the integration of the planetary gear device 35, the planetary gear device 35.45 of the sun gear 31 and ring gear 32. Gear 22. hydraulic clutch 4
5. Rear drive shaft 19. Planetary gear connected by gear 23! [30 is also integrated to lock the differential. Therefore, the front and rear wheels are directly connected and distributed to the TF b-pTR state, maximizing the running performance. The above torque distribution states are summarized in the table below. Although one embodiment of the present invention has been described above, a bevel gear system or the like may be used instead of the planetary gear system of the embodiment as a differential gear device. Torque distribution control can be performed not only according to the above-mentioned driving conditions but also according to the driver's preference, road surface conditions, etc. Furthermore, the present invention can also be applied to a gear train such as a transverse transaxle type or a rear engine with an automatic transmission. [Effects of the Invention] As described above, according to the present invention, power is transmitted by changing the torque distribution between the front and rear wheels, which improves turning performance and stability, and provides performance that suits the purpose and preference. obtain. Since the torque distribution is continuously controlled according to the clutch oil pressure, the optimum torque distribution can be determined for each driving condition. Since the configuration selects three types of torque distribution by the combined operation of two sets of hydraulic clutches, operability is good and control is easy. Since the two sets of hydraulic clutches are distributed on the front and rear drive shafts, it can be made compact. When running at high speeds, only one set of planetary gears operates, so there is less noise.

[Brief explanation of drawings]

Fig. 1 is a skeleton diagram showing an embodiment of the torque distribution control device of the present invention, and Fig. 2 (2) is a characteristic diagram of torque distribution control. 5... Transmission output shaft, 14... Front drive shaft, 19... Rear drive shaft, 30.35... Planetary gear device, 31.36... Sun gear, 32.37
...Ring gear, 34°39...Carrier, 40.
45... Hydraulic clutch, 54... Control unit.

Claims (2)

[Claims] (1) Two sets of differential gear devices for the center differential are interposed in the middle of the drive system for the front and rear wheels, the transmission output shaft is connected to the input element of the first differential gear device, and the first output element is connected to the rear wheels. the second output element is coupled to the input element of the second differential gear device, the first output element of the second differential gear device is connected to the front wheel side, and the second output element is connected to the rear wheel side. a first hydraulic clutch between the first and second output elements of the second differential gear device; and a first hydraulic clutch between the first output element of the first differential gear device and the second
A second hydraulic clutch is provided between the output elements of the first and second hydraulic clutches, and the torques T_F and T_R of the front and rear wheels are controlled by the clutch hydraulic pressure of the first and second hydraulic clutches such that T_F<T_R, T_
A torque distribution control device for a four-wheel drive vehicle that controls three types of distribution: F≒T_R and T_F>T_R. (2) By changing the clutch oil pressure of the first or second hydraulic clutch, T_F<T_R or T_F>
The torque distribution control device for a four-wheel drive vehicle according to claim 1, which continuously changes the distribution amount in the T_R state.