WO2013183447A1

WO2013183447A1 - Driving force distribution device

Info

Publication number: WO2013183447A1
Application number: PCT/JP2013/064165
Authority: WO
Inventors: 哲高石; 淳弘森; 三石　俊一; 永悟坂上; 勝義小川
Original assignee: 日産自動車株式会社
Priority date: 2012-06-05
Filing date: 2013-05-22
Publication date: 2013-12-12

Abstract

If a determination is made that four-wheel drive (4WD) is being requested in S11, normal traction transmission capacity control (i.e., front and rear wheel driving force distribution control) is carried out in S12. If a determination is made that two-wheel drive (2WD) is being requested in S11, a determination is made in S13 as to whether a hydraulic oil temperature (TEMP) is low when said temperature is less than a warm-up request determination temperature (TEMPs) (i.e., warm-up is being requested), or that warm-up has occurred when TEMP ≥ TEMPs. If it is determined that warm-up has occurred, that is, TEMP ≥ TEMPs, control is carried out with the normal traction transmission capacity at zero in S14, and if it is determined that warm-up is being requested, that is, TEMP < TEMPs, ring gears (i.e., rotating roller driving members) are made to reciprocally rotate within an angle range in which a first roller and a second roller do not come into contact with each other in S15, thereby agitating internal hydraulic oil so as to promote the warming of a driving force distribution device.

Description

Driving force distribution device

The present invention relates to a driving force distribution device useful as a transfer for a four-wheel drive vehicle.

Various types of driving force distribution devices have been proposed in the past. For example, a device as described in Patent Document 1 is known.
The driving force distribution device described in this document includes a first roller mechanically coupled to the transmission system of the main driving wheel and a second roller mechanically coupled to the driving system of the driven wheel. A part of the torque to the main driving wheel can be distributed and output to the driven wheel by bringing the first roller and the second roller into radial contact with each other on their outer peripheral surfaces. is there.

In such a driving force distribution device, by adjusting the radial pressing force between the first roller and the second roller, the torque transmission capacity between these rollers, and accordingly, the driving force distribution between the main driving wheel and the sub driving wheel Can be controlled.

As a mechanism for performing this driving force distribution control, Patent Document 1 discloses that the second roller is displaced in the radial direction relative to the first roller by turning the rotation shaft of the second roller around an eccentric axis with a motor or the like. Thus, a configuration has been proposed in which the radial pressing force between the first roller and the second roller, that is, the distribution of the driving force between the main driving wheel and the sub driving wheel can be controlled.

JP 2009-173261 A (FIG. 5)

However, in the driving force distribution device of Patent Document 1, the time during which the internal hydraulic oil is at a low temperature tends to be long, and during this time, the viscosity of the internal hydraulic oil is high and the radial direction between the first roller and the second roller It has been found that there is a concern that the responsiveness of the traction transmission capacity control via the pressing force control becomes poor.

In addition, if the time during which the internal hydraulic oil is at a low temperature becomes longer, the traction transmission capacity between the first roller and the second roller depends on the viscosity of the internal hydraulic oil. It has been found that the device itself cannot be designed as intended, and the deterioration of control accuracy over a long period of time cannot be denied.

In the driving force distribution device of the above-described type, the present inventors have a roller turning member for turning the above-described roller, and the member contacts the first roller and the second roller. I found the fact that there is no rotation area, that is, the traction transmission capacity is zero.
Then, by reciprocating the roller turning member in this rotation region, the internal hydraulic oil is stirred and the temperature rise is promoted, so that the warming-up of the driving force distribution device is promoted and the above problem can be solved.
That is, an object of the present invention is to propose a driving force distribution device that can promote warm-up as described above.

For this purpose, the driving force distribution device according to the present invention is configured as follows.
First of all, to explain the premise driving force distribution device,
A first roller that rotates with the main drive wheel transmission system and a second roller that rotates with the driven wheel transmission system;
The first roller and the second roller are pressed against each other in the radial direction on the outer peripheral surface of each of them, so that the driving force can be distributed to the driven wheels, and one of the first roller and the second roller is turned. The distribution of the driving force between the main driving wheel and the sub driving wheel is controlled by adjusting the radial pressing force between these rollers.

The present invention is characterized by a configuration in which the following warm-up promoting means is provided for such a driving force distribution device.
This warm-up promoting means is configured to reciprocally rotate a roller turning drive member for turning one of the first roller and the second roller within a range in which the first roller and the second roller do not contact each other. The operating oil is stirred to increase the temperature.

According to the driving force distribution device of the present invention, the following effects can be obtained.
That is, the roller rotation drive member for rotating one of the first roller and the second roller to reciprocate the radial pressing force between the rollers is reciprocated within a range where the first roller and the second roller do not contact each other. In order to increase the temperature by stirring the internal hydraulic oil,
Maintaining a state where the traction transmission capacity between the first roller and the second roller is 0, the temperature of the internal hydraulic oil can be quickly raised, and warm-up can be promoted.

Therefore, the state where the viscosity of the internal hydraulic fluid is high at a low temperature can be quickly resolved, and the responsiveness of the traction transmission capacity control via the radial pressing force control between the first roller and the second roller can be quickly achieved. And can avoid the aforementioned responsiveness problems.
In addition, such warm-up promotion can also solve the problem that the traction transmission capacity control itself does not become as designed at the time of design for a long time.

1 is a schematic plan view showing a power train of a four-wheel drive vehicle including a driving force distribution device according to an embodiment of the present invention when viewed from above the vehicle. FIG. 2 is a longitudinal side view of the driving force distribution device in FIG. FIG. 3 is a longitudinal front view showing a crankshaft used in the driving force distribution device shown in FIG. FIG. 3 is an operation explanatory diagram of the driving force distribution device shown in FIG. 2, (a) is an operation explanatory diagram showing a separated state of the first roller and the second roller at a position where the crankshaft rotation angle is 0 ° of the reference point; b) is an operation explanatory diagram showing the contact state of the first roller and the second roller when the crankshaft rotation angle is 90 °, and (c) is the first roller when the crankshaft rotation angle is 180 °. FIG. 6 is an operation explanatory view showing a contact state of the second roller. FIG. 3 is a characteristic diagram showing a change characteristic of crankshaft drive reaction torque (load torque) with respect to the crankshaft rotation angle of the drive force distribution device shown in FIG. FIG. 2 is a flowchart showing a warm-up promotion control program for a driving force distribution device executed by a transfer controller in FIG. 1. FIG.

1 Driving force distribution device (transfer)
2 Engine 3 Transmission 4 Rear propeller shaft 5 Rear

final drive unit

6L, 6R Left and right rear wheels (main drive wheels)
7 Front propeller shaft 8 Front

final drive unit

9L, 9R Left and right front wheels (slave drive wheels)
11 Housing 12 Input shaft 13

Output shaft

16,17 Bearing support 31 1st roller 32 2nd roller 35 Roller radial pressing

force control motor

51L, 51R Crankshaft 51La, 51Ra Hollow hole 51Lb, 51Rb Outer part 51Lc, 51Rc Ring gear ( Roller rotation drive member)
55 Crankshaft drive pinion 56 Pinion shaft 111 Transfer controller 112 Accelerator position sensor 113 Rear wheel speed sensor 114 Yaw rate sensor 115 Crankshaft rotation angle sensor 116 Oil temperature sensor

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

<Configuration>
FIG. 1 is a schematic plan view showing a power train of a four-wheel drive vehicle provided with a driving force distribution device 1 according to an embodiment of the present invention as a transfer as viewed from above the vehicle.

The four-wheel drive vehicle in FIG. 1 is a rear-wheel drive vehicle in which rotation from the engine 2 is transmitted to the left and right

rear wheels

6L and 6R through the rear propeller shaft 4 and the rear final drive unit 5 after being shifted by the transmission 3. As a base vehicle,
A part of the torque to the left and right rear wheels (main drive wheels) 6L, 6R is transmitted to the left and right front wheels (slave drive wheels) 9L, 9R through the front propeller shaft 7 and the front final drive unit 8 sequentially by the driving force distribution device 1. By doing so, the vehicle can be driven by four-wheel drive.

As described above, the driving force distribution device 1 distributes and outputs a part of the torque to the left and right rear wheels (main driving wheels) 6L and 6R to the left and right front wheels (secondary driving wheels) 9L and 9R. (Main drive wheels) 6L, 6R and left and right front wheels (secondary drive wheels) 9L, 9R to determine the drive force distribution ratio. In this embodiment, this drive force distribution device 1 is as shown in FIG. Constitute.

In FIG. 2, reference numeral 11 denotes a housing of the driving force distribution device 1, and the input shaft 12 and the output shaft 13 are horizontally inclined in the housing 11 so that the respective rotation axes O ₁ and O ₂ intersect with each other. To do.
The input shaft 12 is rotatably supported with respect to the housing 11 by

ball bearings

14 and 15 at both ends thereof.
Both ends of the input shaft 12 are protruded from the housing 11 under liquid-tight sealing by

seal rings

25 and 26, respectively.
2, the left end of the input shaft 12 is drivingly coupled to the output shaft of the transmission 3 (see FIG. 1), and the right end is drivingly coupled to the rear final drive unit 5 via the rear propeller shaft 4 (see FIG. 1).

Arranged near the both ends of the input shaft 12 and the output shaft 13, respectively, a pair of bearing supports 16, 17 are installed between the input /

output shafts

12, 13, and the bearing supports 16, 17 are arranged in the middle of each bolt. (Not shown) is attached to the axially opposed inner wall of the housing 11.

Roller bearings

21 and 22 are interposed between the bearing supports 16 and 17 and the input shaft 12 so that the input shaft 12 can be rotated with respect to the bearing supports 16 and 17. However, the input shaft 12 is rotatably supported in the housing 11.

The first roller 31 is integrally formed coaxially at the axial center position of the input shaft 12 between the bearing supports 16, 17 (between the roller bearings 21, 22), and the second roller 32 is positioned at the axial center position of the output shaft 13. Are integrally formed coaxially.
The first roller 31 and the second roller 32 are disposed in substantially the same axis-perpendicular surface so that the outer

peripheral surfaces

31a and 32a of both the rollers can be pressed against each other in the radial direction.
The outer

peripheral surfaces

31a and 32a of the first roller 31 and the second roller 32 are conical tapered surfaces that can be in line contact with each other even when the input shaft 12 and the output shaft 13 are inclined as described above.

In this specification, the first roller 31 and the second roller 32 “contact” with each other (in the outer

peripheral surfaces

31a and 32a) when the first roller 31 and the second roller 32 are in direct contact with each other. It is not limited, and includes cases where they are indirectly contacted through an oil film of internal hydraulic oil, and cases where direct contact and indirect contact are mixed.

The output shaft 13 is pivotally supported with respect to the bearing supports 16 and 17 in the vicinity of both ends thereof, so that the output shaft 13 is rotatably supported in the housing 11 via the bearing supports 16 and 17.
Thus, when the output shaft 13 is pivotally supported with respect to the bearing supports 16 and 17, the following eccentric support structure is used.

A hollow outer

shaft type crankshaft

51L, 51R is loosely fitted between the output shaft 13 and the bearing supports 16, 17 through which the output shaft 13 passes.
The crankshaft 51L and the output shaft 13 protrude from the housing 11 at the left end in FIG. 2, respectively, and the seal ring 27 is interposed between the housing 11 and the crankshaft 51L at the protruding portion, and the seal between the crankshaft 51L and the output shaft 13 is sealed. The crankshaft 51L protruding from the housing 11 and the protruding portion of the output shaft 13 are liquid-tightly sealed with the ring 28 interposed.

2, the left end of the output shaft 13 discharged from the housing 11 is drivingly coupled to the left and right

front wheels

9L and 9R via the front propeller shaft 7 (see FIG. 1) and the front final drive unit 8.

Roller bearings 52L and 52R are interposed between the hollow holes 51La and 51Ra (radius Ri) of the

crankshafts

51L and 51R and the corresponding ends of the output shaft 13, respectively, so that the output shaft 13 is hollow in the

crankshafts

51L and 51R. holes 51La, within 51Ra, supports that can freely rotate around these central axis O _2.

As clearly shown in FIG. 3, the hollow holes 51La and 51Ra (center axis O ₂ ) of the

crankshafts

51L and 51R are eccentric hollow holes eccentric to the outer peripheral portions 51Lb and 51Rb (center axis O ₃ and radius Ro). The central axis O ₂ of the eccentric hollow holes 51La and 51Ra is offset from the central axis O ₃ of the outer peripheral portions 51Lb and 51Rb by the eccentricity ε between them.
The outer peripheral portions 51Lb and 51Rb of the

crankshafts

51L and 51R are rotatably supported in bearing supports 16 and 17 on the corresponding side via

roller bearings

53L and 53R, respectively.
At this time, the

crankshafts

51L and 51R, together with the second roller 32, are positioned in the axial direction by the

thrust bearings

54L and 54R.

Ring gears 51Lc and 51Rc having the same specifications are integrally provided at adjacent ends of the

crankshafts

51L and 51R facing each other, and these ring gears 51Lc and 51Rc are used as roller turning drive members in the present invention.
A common crankshaft drive pinion 55 is engaged with each of the ring gears 51Lc and 51Rc, and the crankshaft drive pinion 55 is coupled to the pinion shaft 56.

As described above, when the crankshaft drive pinion 55 is engaged with the ring gears 51Lc and 51Rc, the rotational positions where the outer peripheral portions 51Lb and 51Rb of the

crankshafts

51L and 51R are aligned in the circumferential direction and in phase with each other. In this state, the crankshaft drive pinion 55 is engaged with the ring gears 51Lc and 51Rc.

Both ends of the pinion shaft 56 are rotatably supported with respect to the housing 11 by

bearings

56a and 56b.
The right end of the pinion shaft 56 on the right side of FIG.
An output shaft 35a of an inter-roller pressing force control motor 35 attached to the housing 11 is drivingly coupled to the exposed end surface of the pinion shaft 56 by serration fitting or the like.

Therefore, when the rotational position of the

crankshafts

51L, 51R is controlled by the inter-roller radial pressing force control motor 35 via the pinion 55 and the ring gears 51Lc, 51Rc,
The rotation axis O ₂ of the output shaft 13 and the second roller 32 turns around the central axis O ₃ along a locus circle α indicated by a broken line in FIG.

The second roller 32 is rotated by the rotation axis O ₂ (second roller 32) along the locus circle α in FIG. 3, but the first roller 31 will be described in detail later, as shown in FIGS. 4 (a) to 4 (c). As the rotation angle θ of the

crankshafts

51L and 51R increases, the radius L1 between the first roller 31 and the second roller 32 increases. It can be made smaller than the sum of the radius.
Due to such a decrease in the distance L1 between the roller shafts, the radial pressing force of the second roller 32 against the first roller 31 (the transmission torque capacity between the rollers: traction transmission capacity) increases, and according to the degree of decrease in the distance L1 between the roller axes. The inter-roller radial pressing force (inter-roller transmission torque capacity: traction transmission capacity), that is, the driving force distribution ratio can be arbitrarily controlled.

As shown in FIG. 4 (a), in this embodiment, the second roller rotation axis O ₂ is located immediately below the crankshaft rotation axis O ₃ and the inter-axis distance L1 between the first roller 31 and the second roller 32 is The distance L1 between the roller axes at the maximum bottom dead center is made larger than the sum of the radius of the first roller 31 and the radius of the second roller 32.
Thus, at the bottom dead center of the crankshaft rotation angle θ = 0 °, the first roller 31 and the second roller 32 are not pressed against each other in the radial direction, and traction transmission is performed between the

rollers

31 and 32. No traction transmission capacity = 0 can be obtained,
The traction transmission capacity can be arbitrarily controlled between 0 at the bottom dead center and the maximum value obtained at the top dead center (θ = 180 °) shown in FIG.

In this embodiment, the description will be made assuming that the rotation angle reference point of the

crankshafts

51L and 51R is the bottom dead center of the crankshaft rotation angle θ = 0 °.

In this embodiment also, configured to moderate rotation while turning around the axis O ₃ by the axis O ₂ of the motor 35, the radial pressing force of second roller 32 relative to the first roller 31 of the second roller 32 as described above for,
A driving reaction force torque (load torque) Tcr as shown in FIG. 5 acts on the

crankshafts

51L and 51R according to the crankshaft rotation angle θ, as will be described in detail later.

<Driving force distribution action>
The drive force distribution action of the transfer 1 described above with reference to FIGS. 1 to 4 will be described below.
On the other hand, the torque that has reached the input shaft 12 of the transfer 1 from the transmission 3 (see FIG. 1) passes directly from the input shaft 12 through the rear propeller shaft 4 and the rear final drive unit 5 (both see FIG. 1) to the left and right rear wheels 6L. , 6R (main drive wheel).

On the other hand, the transfer 1 controls the rotational position of the

crankshafts

51L and 51R via the pinion 55 and the ring gears 51Lc and 51Rc by the motor 35, and the distance L1 between the roller axes (see FIG. 4) is set to the first roller 31 and the second roller 32. Since the

rollers

31, 32 have a torque transfer capacity between the rollers according to the radial mutual pressing force, the left and right

rear wheels

6L, 6R (main A part of the torque to the drive wheels) is directed from the first roller 31 to the output shaft 13 via the second roller 32, and the left and right

front wheels

9L and 9R (secondary drive wheels) can also be driven.
Thus, the vehicle is capable of four-wheel drive running by driving all of the left and right

rear wheels

6L and 6R (main drive wheels) and the left and right front wheels (secondary drive wheels) 9L and 9R.

Note that the radial pressing reaction force Ft between the first roller 31 and the second roller 32 during this transmission is received by the bearing supports 16 and 17 which are rotation support plates common to these, and does not reach the housing 11. .
The radial pressing reaction force Ft is 0 when the crankshaft rotation angle θ is 0 ° to 90 °, and increases as θ increases while the crankshaft rotation angle θ is 90 ° to 180 °. When the crankshaft rotation angle θ is 180 °, the maximum value is obtained.

Due to the radial pressing reaction force Ft, the crankshaft drive reaction torque (load torque) Tcr expressed by the following equation acts on the

crankshafts

51L and 51R,
Tcr = Ft × Ro × sinθ
The crankshaft driving reaction torque (load torque) Tcr exhibits a non-linear characteristic as shown in FIG. 5 with respect to the crankshaft rotation angle θ, as is apparent from the above equation.

During such four-wheel drive traveling, the rotation angle θ of the

crankshafts

51L and 51R is 90 ° of the reference position as shown in FIG. 4 (b), and the first roller 31 and the second roller 32 are mutually connected. When pressing and contacting with a radial pressing force corresponding to the offset amount OS at the time,
Power is transmitted to the left and right front wheels (sub driven wheels) 9L and 9R with a traction transmission capacity corresponding to the offset amount OS between these rollers.

Then, the

crankshafts

51L and 51R are rotated from the reference position in FIG. 4 (b) toward the top dead center of the crankshaft rotation angle θ = 180 ° shown in FIG. 4 (c) to increase the crankshaft rotation angle θ. As a result, the distance L1 between the roller shafts further decreases, and the mutual overlap amount OL of the first roller 31 and the second roller 32 increases. As a result, the first roller 31 and the second roller 32 increase the radial mutual pressing force. Thus, the traction transmission capacity between these rollers can be increased.

When the

crankshafts

51L and 51R reach the top dead center position in FIG. 4 (c), the first roller 31 and the second roller 32 are in the radial direction with a maximum radial pressing force corresponding to the maximum overlap amount OL. The traction transmission capacity between them can be maximized.
The maximum overlap amount OL is the sum of the eccentric amount ε between the second roller rotation axis O ₂ and the crankshaft rotation axis O ₃ and the offset amount OS described above with reference to FIG. 4B.

As is apparent from the above description, the crankshaft rotation angle is controlled by rotating the

crankshafts

51L and 51R from the rotation position of the crankshaft rotation angle θ = 0 ° to the rotation position of the crankshaft rotation angle θ = 180 °. As θ increases, the traction transmission capacity between rollers can be continuously changed from 0 to the maximum value.
Conversely, by rotating the

crankshaft

51L, 51R from the rotation position of the crankshaft rotation angle θ = 180 ° to the rotation position of θ = 0 °, the traction transmission between the rollers is reduced as the crankshaft rotation angle θ decreases. The capacity can be continuously changed from the maximum value to 0, and the traction transmission capacity between the rollers can be freely controlled by rotating the

crankshafts

51L and 51R.

<Traction transmission capacity control>
Because the transfer 1 distributes a part of the torque to the left and right rear wheels (main drive wheels) 6L and 6R to the left and right front wheels (secondary drive wheels) 9L and 9R as described above during the four-wheel drive driving described above. The left and right front wheels (slave drive wheels) can determine the traction transmission capacity between the first roller 31 and the second roller 32 from the driving force of the left and right

rear wheels

6L, 6R (main driving wheels) and the front and rear wheel target driving force distribution ratio. It is necessary to correspond to the target front wheel drive force to be distributed to 9L and 9R.

In the present embodiment, in order to control the traction transmission capacity that meets this requirement, a transfer controller 111 is provided as shown in FIG. 1, thereby controlling the rotational position of the motor 35 (control of the crankshaft rotational angle θ). To do.

Therefore, the transfer controller 111 has
A signal from an accelerator opening sensor 112 that detects an accelerator pedal depression amount (accelerator opening) APO that adjusts the output of the engine 2;
A signal from the rear wheel speed sensor 113 that detects the rotational peripheral speed Vwr of the left and right

rear wheels

6L, 6R (main drive wheels);
A signal from the yaw rate sensor 114 for detecting the yaw rate φ around the vertical axis passing through the center of gravity of the vehicle;
A signal from the crankshaft rotation angle sensor 115 for detecting the rotation angle θ of the

crankshafts

51L and 51R;
A signal from an oil temperature sensor 116 that detects the temperature TEMP of the hydraulic oil in the transfer 1 (housing 11) is input.

The transfer controller 111 performs the traction transmission capacity control of the transfer 1 (front and rear wheel driving force distribution control of a four-wheel drive vehicle) based on the input information as follows.
That is, first, the transfer controller 111 first knows the driving force of the left and right

rear wheels

6L and 6R (main driving wheels) and the front and rear wheel target driving force distribution ratio based on the accelerator opening APO, the rear wheel speed Vwr, and the yaw rate φ. Ask for.
Next, the transfer controller 111 determines the target front wheel drive force to be distributed to the left and right front wheels (secondary drive wheels) 9L and 9R from the drive force of the left and right

rear wheels

6L and 6R (main drive wheels) and the front and rear wheel target drive force distribution ratio. Ask for.

Further, the transfer controller 111 determines the radial pressing force between the rollers required for the first roller 31 and the second roller 32 to transmit the target front wheel driving force (the traction transmission capacity between the first roller 31 and the second roller 32). Of the

crankshafts

51L and 51R (see Figs. 2 and 3) required to achieve the radial pressure between the rollers (the traction transmission capacity between the first roller 31 and the second roller 32). The rotation angle target value tθ, that is, the target turning position of the second roller axis O ₂ is calculated.

Then, the transfer controller 111 changes the crankshaft rotation angle θ to the crankshaft rotation angle target value tθ in accordance with the crankshaft rotation angle deviation between the crankshaft rotation angle θ detected by the sensor 115 and the crankshaft rotation angle target value tθ. The roller pressing force control motor 35 is driven and controlled so as to match.
When the rotation angle θ of the

crankshafts

51L and 51R matches the target value tθ by the drive control of the motor 35, the first roller 31 and the second roller 32 can transmit the target front wheel driving force to each other in the radial direction. The traction transmission capacity between the first roller 31 and the second roller 32 can be controlled so as to become the front and rear wheel target driving force distribution ratio.

<Transfer warm-up acceleration control>
The transfer controller 111 executes the following warm-up promotion control by executing the control program shown in FIG. 6 in addition to the above-described normal traction transmission capacity control (front and rear wheel driving force distribution control of a four-wheel drive vehicle). .

In step S11, it is checked whether four-wheel drive (4WD) is required to distribute the driving force to the left and right front wheels (secondary drive wheels) 9L, 9R, and four-wheel drive (4WD) is requested. In the case of determination, the control proceeds to step S12, and the above-described normal traction transmission capacity control (front and rear wheel driving force distribution control) is performed.

If it is determined in step S11 that four-wheel drive (4WD) is not requested, control proceeds to step S13, and the internal hydraulic oil temperature TEMP of transfer 1 is less than the warm-up request determination temperature TEMPs (warm-up is requested). Whether the oil temperature TEMP is equal to or higher than the warm-up request determination temperature TEMPs (a state where warm-up is not requested).

If it is determined in step S13 that TEMP ≧ TEMPs (a state where warm-up is not required), the control proceeds to step S14 so that the driving force is not distributed to the left and right front wheels (secondary driving wheels) 9L, 9R. Perform normal traction transmission capacity 0 control.
This traction transmission capacity 0 control is as close as possible to the position of the crankshaft rotation angle θ = 90 ° shown in FIG. 4 (b), but a predetermined crank having a slight gap between the first roller 31 and the second roller 32. In this control, the

crankshafts

51L and 51R (see FIGS. 2 and 3) are held at the shaft rotation angle position.

If it is determined in step S13 that TEMP <TEMPs (a state where warm-up is required), the control proceeds to step S15, where the crankshaft rotation angle reference point (crankshaft absolute angle) is estimated as follows. .
That is, when the

crankshafts

51L and 51R (see FIGS. 2 and 3) are rotated in one direction and the first roller 31 and the second roller 32 start to contact each other, the crankshaft rotation position and the

crankshafts

51L and 51R The crankshaft rotation angle θ when the

crankshafts

51L and 51R are rotated in the middle of the crankshaft rotation position when the first roller 31 and the second roller 32 start to contact each other. The shaft rotation angle reference point (crankshaft absolute angle) is used.
In the case of this embodiment, as described above with reference to FIG. 4, the crankshaft rotation angle θ at the bottom dead center shown in FIG. 4A is the rotation angle reference point (crankshaft absolute angle) of the

crankshafts

51L and 51R. The crankshaft rotation angle θ here is assumed to be θ = 0 °.

In the next step S16, in response to the 2WD request determination in step S11, in order to keep the driving force from being distributed to the left and right front wheels (secondary driving wheels) 9L, 9R at the crankshaft rotation angle reference point, The crankshaft rotation angle θ is 0 °, and the

crankshafts

51L and 51R, together with the ring gears 51Lc and 51Rc (roller turning drive members) integral therewith, the first roller 31 and the second roller 32 do not contact each other θ = Reciprocate within the angle range of -β to + β.
Note that β is an angle smaller than 90 ° by an amount corresponding to the offset amount OS described above with reference to FIG.

The reciprocating rotation of the ring gears 51Lc and 51Rc (roller turning drive members) within the angular range (θ = −β to + β) in which the first roller 31 and the second roller 32 do not contact each other is determined in step S11. While maintaining the two-wheel drive (2WD) state based on the result, the internal hydraulic fluid of the transfer 1 (housing 11) is agitated, and the temperature rise can be promoted to promote the warm-up of the transfer 1.
Accordingly, step S16 corresponds to warm-up promoting means in the present invention.

<Effect>
According to the warm-up promotion control of the transfer 1 according to the present embodiment described above with reference to FIG.
When the four-wheel drive (4WD) is not required (step S11) and the low temperature (TEMP <TEMPs) state (step S13) is required to promote warm-up of the transfer 1,
Ring gears 51Lc and 51Rc (roller turning drive members) for turning the second roller 32 to adjust the radial pressing force between the first roller 31 and the second roller 32 are provided by the first roller 31 and the second roller 32. In order to increase the temperature by agitating the internal hydraulic fluid of the transfer 1 (step S16) by reciprocating rotation within the range of crankshaft rotation angles θ = −β to + β that do not contact each other,
While the traction transmission capacity between the first roller 31 and the second roller 32 is maintained at 0, the temperature of the internal hydraulic oil can be quickly raised to promote warm-up.

Therefore, the state where the viscosity of the transfer hydraulic fluid is high at a low temperature can be quickly resolved, and the responsiveness of the traction transmission capacity control via the radial pressing force control between the first roller 31 and the second roller 32 can be quickly achieved. It can be made original, and the problem related to the responsiveness of the traction transmission capacity control can be solved.
In addition, such warm-up promotion can also solve the problem that the traction transmission capacity control itself does not become as designed at the time of design for a long time.

Further, the ring gear 51Lc, 51Rc are rotatably supported by the housing 11 of the transfer 1, the ring gear 51Lc, and rotatably supported to the second roller 32 at a position O ₂ which is eccentric by the eccentricity ε from the rotation center O ₃ of 51Rc Because it is configured to cause the second roller 32 to turn by the rotation of the ring gears 51Lc, 51Rc,
The warm air promoting means can be configured simply, and as a result, an increase in weight and cost of the driving force distribution device can be suppressed to a minimum.

Furthermore, when the four-wheel drive (4WD) is not required (step S11) and the low temperature (TEMP <TEMPs) state (step S13) is required to warm up the transfer 1, the ring gear 51Lc, The 51Rc (roller turning drive member) is reciprocally rotated within the angle range (θ = −β to + β) in which the first roller 31 and the second roller 32 do not contact each other so that the above-described effects can be obtained. ,
When four-wheel drive (4WD) is being requested (step S11), the ring gears 51Lc and 51Rc (roller swivel drive) are used even in the low temperature (TEMP <TEMPs) state (step S13) where the transfer 1 is required to warm up. The above-mentioned reciprocating rotation of the member) is not performed, and the four-wheel drive (4WD) request is not realized.

Claims

A first roller that rotates with the main drive wheel transmission system and a second roller that rotates with the driven wheel transmission system;
The first roller and the second roller are pressed against each other in the radial direction on the outer peripheral surface of each of them, so that the driving force can be distributed to the driven wheels, and one of the first roller and the second roller is turned. Then, in the driving force distribution device that controls the driving force distribution between the main driving wheel and the sub driving wheel by adjusting the radial pressing force between these rollers,
By rotating the roller turning drive member for turning one of the first roller and the second roller in a range where the first roller and the second roller do not contact each other, the internal hydraulic oil is stirred and the temperature is increased. A driving force distribution device provided with warming-up promotion means for increasing the temperature.
In the driving force distribution device according to claim 1,
The roller turning drive member is rotatably supported by the housing of the driving force distribution device, and rotatably supports one of the turned rollers at a position eccentric from the rotation center of the roller turning drive member. Yes,
A driving force distribution device configured to cause the one roller to turn by the rotation of the roller turning drive member.
In the driving force distribution device according to claim 1 or 2,
The warming-up promoting means moves the roller turning drive member to the first roller and the first roller when it is not necessary to distribute driving force to the driven wheels and the internal hydraulic oil is lower than a set temperature. A driving force distribution device characterized in that the two rollers are reciprocally rotated within a range where they do not contact each other.