JP2519635Y2 - Drive force distribution device for four-wheel drive vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a driving force distribution device for a four-wheel drive vehicle.

(Prior Art) As one type of driving force distribution device for a four-wheel drive vehicle, a planetary gear unit having one input element and two output elements is provided, and the input element is connected to an output member of a driving force source and There is a driving force distribution device in which an output element is connected to each output member for front and rear wheels, and an example of this type of driving force distribution device is disclosed in Japanese Patent Laid-Open No. 62-55228. The drive force distribution device includes a drive transmission control clutch that connects and disconnects the first output element of the planetary gear unit and an output member to one of the front and rear wheels, and a differential control clutch that connects and disconnects both output elements. Providing two-wheel drive by engaging the differential control clutch and releasing the drive transmission control clutch (first drive mode), releasing the differential control clutch and engaging the drive transmission control clutch. By so doing, a four-wheel drive that allows a differential is achieved (second drive mode), and by engaging both clutches together, a four-wheel drive that restricts differential is achieved (third drive mode). ing. The torque distribution ratio to the front and rear wheels (front wheel or rear wheel) / (rear wheel or front wheel) in each of these drive modes is 0/100 in the first drive mode, and ZS / ZR in the second drive mode (however, ZS is the number of teeth of the sun gear, ZR is the number of teeth of the ring gear ...
For example, 30/70) and 50/50 in the third drive mode.

(Problems to be Solved by the Invention) By the way, in the driving force distribution device, torque distribution is performed in each drive mode, that is, in the range of the torque distribution ratio between the first and third drive modes and between the second and third drive modes. In order to variably control the ratio and allow the vehicle to travel at the optimum torque distribution ratio, a clutch capable of variably controlling torque transmission between the connecting members may be adopted as each of the above-mentioned clutches. For example, when a variable controllable clutch of torque transmission is adopted as the differential control clutch, the first transmission element of the planetary gear unit and the output member for one of the front and rear wheels are coupled by the drive transmission control clutch. If the differential control clutch is variably controlled, the torque distribution ratio can be adjusted within the range of the second and third drive modes.
It can be changed in the range of 30/70 to 50/50. Also,
When a clutch capable of variably controlling torque transmission is adopted as the drive transmission control clutch, if the drive transmission control clutch is variably controlled while both output elements of the planetary gear unit are connected by the differential control clutch, the torque distribution ratio Can be changed in the range of 0/100 to 50/50 in the first and third drive modes.

Therefore, when the torque distribution ratio is variably controlled in both of the ranges described above, both the drive transmission control clutch and the differential control clutch are variably controllable torque transmission clutches. In addition, an actuator for controlling the operation of the clutch and a control device for controlling the operation of the actuator are required. As a result, there is a new problem that the cost of the driving force distribution device increases and the size of the driving force distribution device increases.

Therefore, an object of the present invention is to adopt a variable controllable clutch for torque transmission in one of the two clutches when the torque distribution ratio is variably controlled in the above two ranges. The problem is solved by making the ratio variably controllable.

(Means for Solving the Problem) The present invention comprises a planetary gear unit having one input element and two output elements, the input element being connected to an output member of a driving force source, and each output element being a front and rear wheel. In the driving force distribution device for a four-wheel drive vehicle, which is connected to each of the output members, the input element and one of the front and rear wheels are connected to transmit the driving force, and the first output element and the front and rear A drive transmission control clutch for connecting one of the output members of the wheels to transmit a drive force, and a differential control clutch for variably controlling torque transmission between the two output elements. It is characterized by.

(Operation / Effect of the Invention) In the drive force distribution device having such a configuration, the first element in which the input element of the planetary gear and the output member (first output member) to one of the front and rear wheels are connected by the drive transmission control clutch.
And a second connection state in which the first output element of the planetary gear unit and the first output member are connected (state in which the function of the planetary gear unit is effective) can do.
For this reason, if the differential control clutch is variably controlled in the first connected state and the torque transmissibility between both output elements of the planetary gear unit is changed within the range of 0 to 100%, the torque distribution ratio to the front and rear wheels is increased. It can be changed in the range of 0/100 to 50/50. Further, if the differential control clutch is variably controlled in the second connected state to change the torque transmission ratio between the two output elements of the planetary gear unit to a range of 0 to 100%, the torque distribution ratio to the front and rear wheels is set to, for example, It can be changed in the range of ZS / ZR to 50/50.

Therefore, in the driving force distribution device, it is possible to achieve the variable control in the range of the both torque distribution ratios only by adopting the clutch capable of variably controlling the torque transmission as the differential control clutch. It is possible to suppress an increase in cost and an increase in size.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a driving force distribution device according to a first embodiment of the present invention. The drive force distribution device 10 includes a planetary gear unit 10a as a center differential, a drive transmission control clutch 10b, and a differential control clutch 10c.

The planetary gear unit 10a includes a sun gear 11 and a carrier 1.
2 comprises a plurality of planetary gears 13 and a ring gear 14 rotatably supported, and a carrier 12 is connected to an output shaft t of a transmission T / M and is configured as an input element of a driving force of an engine E / G. . The sun gear 11 is connected to a front wheel output shaft 15 that outputs drive torque to the front wheel side and is configured as a second output element, and the ring gear 14 is described later on a rear wheel output shaft 16 that outputs drive torque to the rear wheel side. 1st selectively connected via the drive transmission control clutch 10b
Is configured as an output element of. Front wheel output shaft 15 is an output gear
A front propeller shaft 19c is coupled to the front propeller shaft 19c via a counter gear 19a and a counter gear 19b so that torque can be transmitted.

As shown in FIGS. 1 and 2, the drive transmission control clutch 10b includes a switching sleeve 17, a spline 18a provided on a connecting shaft 18 coaxially connected to the carrier 12, a spline 16a provided on the rear wheel output shaft 16, and a ring gear. The switching sleeve 17 is slidably mounted on a fork shaft 19d supported by a transfer case by a shift fork 19e that is intermittently slidable, and meshes with both splines 16a and 18a. And carrier 12 and rear wheel output shaft
A first switching mode (first connection state) for connecting 16 and
Second switching mode (second connection state) in which the ring gear 14 and the rear wheel output shaft 16 are engaged with each other by meshing with both splines 14a and 16a
Is configured. The shift fork 19e is operated by the driver. The differential control clutch 10c is a hydraulically operated clutch with a variable clutch torque capacity, which is a sun gear 11 and a ring gear.
Variable control of the clutch torque capacity is provided between 14 and is performed by a hydraulic control valve (not shown) and a control device that controls the differential of the valve.

In the driving force distribution device 10 having such a configuration, the carrier
In the first switching mode in which 12 and the rear wheel output shaft 16 are connected,
The rear wheel output shaft 16 is directly connected to the output shaft of the transmission T / M, and the front wheel output shaft 15 is connected to the ring gear 14 via the differential control clutch 10c. Therefore, the clutch torque capacity of the differential control clutch 10c is controlled to control the clutch 10c.
By changing the torque transmission ratio of 0 to 100%, the torque distribution ratio of the front wheels / rear wheels can be changed in the range of 0/100 to 50/50. In addition, the ring gear 14 and the rear wheel output shaft 16
In the second switching mode in which the and are coupled, in the planetary gear unit 10a, the drive torque is distributed to the sun gear 11 and the ring gear 14 and transmitted to both output shafts 15 and 16. Therefore, if the clutch torque capacity of the differential control clutch 10c is controlled and the torque transmission rate of the clutch 10c is changed within the range of 0 to 100%, the torque distribution ratio of the front wheels / rear wheels is ZS / ZR.
It can be varied in the range of -50/50, for example in the range of 30 / 70-50 / 50. However, ZS is the number of teeth of the sun gear 11, and ZR is the number of teeth of the ring gear 14.

Therefore, in the driving force distribution device 10, only by adopting a clutch capable of variably controlling the torque capacity as the differential control clutch 10c, it is possible to variably control the distribution torque within the range of the both torque distribution ratios. As compared with the case where two clutches capable of variably controlling torque transmission are adopted, the hydraulic control valve and the operation control device for the valve may be provided in a single set, thereby suppressing an increase in cost and an increase in size of the device. it can.

FIG. 3 shows a driving force distribution device according to a second embodiment of the present invention.
20 is shown, and the drive force distribution device 20 includes a planetary gear unit 20a as a center differential, a drive transmission control clutch 20b, and a differential control clutch 20c. The planetary gear unit 20a is of the double pinion type, the sun gear 21 is connected to the front wheel output shaft 25 to constitute a second output element, and the carrier 22 is selectively connected to the rear wheel output shaft 26 via the drive transmission control clutch 20b. A first output element connected to and a ring gear
24 are configured as input elements.

Drive transmission control clutch 20b and differential control clutch 20c
Has the same structure as the drive transmission control clutch 10b and the differential control clutch 10c of the first embodiment. The drive transmission control clutch 20b has a ring gear 24 which is an input element and a carrier 22 which is a first output element. The differential control clutch 20c is selectively connected to the output shaft 26, and variably controls torque transmission between the sun gear 21 and the carrier 22 which are both output elements.

In FIG. 3, reference numeral 27 is a switching sleeve and reference numeral 29.
Reference symbol a indicates an output gear assembled to the front wheel output shaft 25, reference symbol 29b indicates a counter gear, and reference symbol 29c indicates a front propeller shaft.

Therefore, in the driving force distribution device 20 having such a configuration,
The first switching mode in which the ring gear 24 and the rear wheel output shaft 26 are connected, and the second in which the carrier 22 and the rear wheel output shaft 26 are connected.
A switching mode is configured. In the case of this first switching mode,
The rear wheel output shaft 26 is directly connected to the output shaft of the transmission, and the front wheel output shaft 25 is connected to the carrier 22 via the differential control clutch 20c. Therefore, the differential control clutch
By controlling the clutch torque capacity of the 20c and changing the torque transfer rate of the clutch 20c within the range of 0 to 100%,
The torque distribution ratio of the rear wheels can be changed within the range of 0/100 to 50/50. Further, in the second switching mode in which the carrier 22 and the rear wheel output shaft 26 are connected, the planetary gear unit
In 20a, the drive torque is distributed to the sun gear 21 and the carrier 22 and transmitted to both output shafts 25 and 26. For this reason,
If the clutch torque capacity of the differential control clutch 20c is controlled to change the torque transmission rate of the clutch 20c within the range of 0 to 100%, the torque distribution ratio of the front wheels / rear wheels is ZS / (ZR-ZS).
It can be changed in the range of up to 50/50. However, ZS is the number of teeth of the sun gear 21, and ZR is the number of teeth of the ring gear 24.

As described above, also in the second embodiment, the variable control of the distribution torque within the range of the both torque distribution ratios can be performed only by adopting the clutch capable of variably controlling the torque capacity as the differential control clutch 20c. The same effect as the first embodiment is obtained.

[Brief description of drawings]

FIG. 1 is a skeleton diagram of a driving force distribution device according to a first embodiment of the present invention, FIG. 2 is a sectional view of an essential part of a drive transmission control clutch of the device, and FIG. 3 is a driving force according to the second embodiment. It is a skeleton diagram of a distributor. Explanation of symbols 10,20 …… Drive power distribution device, 10a, 20a …… Planetary gear unit, 10b, 20b …… Drive transmission control clutch, 10c, 20c
...... Differential control clutch, 11,21 …… Sun gear, 12,22 ……
Carrier, 14,24 …… Ring gear, 15,25 …… Front wheel output shaft, 16,26 …… Rear wheel output shaft.

Claims (1)

(57) [Scope of utility model registration request] 1. A planetary gear unit having one input element and two output elements, wherein the input element is connected to an output member of a drive source and each output element is connected to each output member to front and rear wheels. In a four-wheel drive vehicle driving force distribution device, a state in which a driving force is transmitted by connecting the input element and one of the front and rear wheels, and a state in which the first output element and one of the front and rear wheels are connected. And a differential transmission clutch for variably controlling torque transmission between the both output elements, and a four-wheel drive. Vehicle drive force distribution device.