WO2013183411A1

WO2013183411A1 - Driving force distribution device

Info

Publication number: WO2013183411A1
Application number: PCT/JP2013/063515
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: 2012-06-04
Filing date: 2013-05-15
Publication date: 2013-12-12

Abstract

When positioning an oil temperature sensor (116), the oil temperature sensor (116) is positioned such that an oil temperature sensing end (116a) is positioned behind an outer peripheral surface mutual contact point on a first roller (31) and a second roller (32) in the direction of rotation (indicated by arrows) of the first roller (31) and the second roller (32). The oil temperature sensor (116) is preferably positioned such that the oil temperature sensing end (116a) is immersed in hydraulic fluid (61) inside a driving force distribution device (1) (a housing (11)), and is positioned between the outer peripheral surface mutual contact point on the first roller (31) and the second roller (32), and a common contact plane (M) that touches the outer peripheral surfaces (31a, 32a) of the first roller (31) and the second roller (32) further behind in the direction of rotation of the rollers than the outer peripheral surface mutual contact point, in other words, the oil temperature sensing end (116a) is positioned just behind the outer peripheral surface mutual contact point on the first roller (31) and the second roller (32) in the direction of rotation of the rollers.

Description

Driving force distribution device

The present invention relates to a driving force distribution device, and more particularly to a driving force distribution device used as a transfer for a four-wheel drive vehicle.

As a conventional driving force distribution device, 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. By bringing the first roller and the second roller into contact with each other on the outer peripheral surfaces of them, a part of the torque to the main driving wheel can be distributed to the driven wheel and output.

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.

Japanese Patent Laying-Open No. 2009-173261 (FIG. 5)

In the above-described radial pressing force control between the first roller and the second roller (drive force distribution control between the main drive wheel and the slave drive wheel), fail-safe control for preventing the outer peripheral surface of the roller from peeling off at the time of overheating, An oil temperature sensor that detects the temperature of hydraulic oil (traction oil) in the driving force distribution device is required for traction force compensation control that compensates for changes in traction transmission characteristics between rollers (change in traction force) due to temperature. .

Incidentally, Patent Document 1 does not mention anything about the arrangement of the oil temperature sensor.
However, the temperature distribution of the internal hydraulic fluid varies widely, and depending on the location of the oil temperature sensor, the hydraulic fluid temperature detected by this cannot represent the temperature of the essential contact surface between the rollers. Control responses such as fail-safe control and traction force compensation control are deteriorated, resulting in a problem that the control accuracy is lowered and the desired control effect cannot be obtained.
In the driving force distribution device that does not make any contrivance regarding the arrangement of the oil temperature sensor as in the prior art represented by Patent Document 1, the occurrence of the problem is unavoidable.

According to the present invention, in the driving force distribution device of the above type, it is important to know the temperature of the mutual contact surface between the rollers, and the roller is scraped from between the rollers immediately after the roller rotation direction of the mutual contact surface of the roller outer peripheral surface. Based on the recognition that the temperature of the hydraulic oil is close to the temperature of the contact surface between the rollers, a driving force that can solve the above problem by arranging an oil temperature sensor to detect the temperature of the hydraulic oil here The purpose is to propose a distribution device.

For this purpose, the driving force distribution device according to the present invention is configured as follows.
First, the driving force distribution device as a premise will be described. This includes a first roller that rotates together with the main drive wheel transmission system, and a second roller that rotates together with the driven wheel transmission system.
The first roller and the second roller are brought into contact with each other on their outer peripheral surfaces so that power can be transmitted, and the driving force is distributed to the driven wheels, and the radial pressing force between the first roller and the second roller is adjusted. As a result, the driving force distribution control between the main driving wheel and the sub driving wheel is possible, and at least the temperature of the hydraulic oil is used as a control factor of the driving force distribution control.

The present invention provides an oil temperature sensor for detecting the temperature of the hydraulic oil in the driving force distribution device, wherein the first roller and the second roller are in mutual contact with each other in the rotation direction of the first roller and the second roller. Characterized by the configuration placed behind the location.

According to such a driving force distribution device of the present invention, the oil temperature sensor for detecting the temperature of the hydraulic oil is arranged such that the outer peripheral surface mutual contact portions of the first roller and the second roller in the rotation direction of the first roller and the second roller. Since the hydraulic oil temperature detected by the oil temperature sensor is close to the temperature at the contact point between the outer surfaces of the first roller and the second roller, control responses such as the fail-safe control and the traction force compensation control described above are performed. The control effect can be achieved as intended by improving the control accuracy.

1 is a schematic plan view showing a power train of a four-wheel drive vehicle including a driving force distribution device according to a first embodiment of the present invention as viewed from above the vehicle. FIG. 2 is a longitudinal side view showing the driving force distribution device in FIG. 1 in an exploded manner. FIG. 3 is a longitudinal front view of 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 schematic front view of the driving force distribution device showing the location of the oil temperature sensor with respect to the driving force distribution device of FIG. FIG. 2 is a flowchart showing an overheating fail-safe control program of the driving force distribution device executed by the transfer controller in FIG. 1. FIG. 7 is a flowchart showing a traction force compensation control program for a driving force distribution device according to a second embodiment of the present invention. FIG. 3 is a characteristic diagram illustrating a temperature change characteristic of a traction coefficient between a first roller and a second roller in the driving force distribution device shown in FIG. 7 is a flowchart showing a control program related to overheat fail-safe control and traction force compensation control of a driving force distribution device according to a third embodiment of the present invention.

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 pressing

force control motor

51L, 51R Crankshaft 51La, 51Ra Hollow hole 51Lb, 51Rb Outer part 51Lc, 51Rc Ring gear 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 116a Oil temperature detection end

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 a first 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,
Part of the torque to the left and right rear wheels (main drive wheels) 6L and 6R is transmitted to the left and right front wheels (secondary drive wheels) 7L and 7R 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) 7L and 7R. (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 arranged in the housing 11 so that the respective rotation axes O ₁ and O ₂ are parallel to each other. Mount.
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.

A first roller 31 is coaxially and integrally formed at a position in the axial direction of the input shaft 12 between the bearing supports 16 and 17 (between the roller bearings 21 and 22).
The second roller 32 is coaxially formed integrally with the first roller 31 so as to be in contact with the first oil roller 31 so that power can be transmitted through the hydraulic oil.
Due to the parallel arrangement of the input shaft 12 and the output shaft 13, the outer

peripheral surfaces

31a and 32a of the first roller 31 and the second roller 32 are cylindrical surfaces that can come into line contact with each other.

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 the 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 of the same specification are integrally provided at adjacent ends of the

crankshafts

51L and 51R facing each other.
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 °.

<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 between the first roller 31 and the second roller 32 during the transmission is received by the bearing supports 16 and 17 which are rotation support plates common to them, and does not reach the housing 11.
The radial pressing reaction force 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 °. The maximum value is obtained when the crankshaft rotation angle θ is 180 °.

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 it is pressed with a radial pressing force corresponding to the offset amount OS at the time and is in contact so that power can be transmitted via hydraulic oil,
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.

As shown in the schematic front view of FIG. 5 relating to the driving force distribution device 1, the oil temperature sensor 116 is used in the rotational directions of the first roller 31 and the second roller 32 (respectively indicated by arrows in FIG. 5). The oil temperature detection end portion 116a of the oil temperature sensor 116 is positioned behind the location where the outer peripheral surfaces of the first roller 31 and the second roller 32 are in mutual contact (location where torque is transmitted via the hydraulic oil).

At this time, the oil temperature sensor 116 has its oil temperature detection end portion 116a immersed in the hydraulic oil 61 in the driving force distribution device 1 (housing 11), and the outer peripheral surfaces of the first roller 31 and the second roller 32. Between the mutual contact point and the common contact surface M that contacts the outer

peripheral surfaces

31a and 32a of the first roller 31 and the second roller 32 at the rear of the outer peripheral surface mutual contact point, that is, in the roller rotational direction. The first roller 31 and the second roller 32 are preferably arranged so as to be located immediately after the contact point between the outer peripheral surfaces.

The transfer controller 111 performs 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 detection information of the sensors 112 to 116 as described below.
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.
The rotation angle θ of the

crankshafts

51L and 51R matches the target value tθ by the drive control of the motor 35, so that the first roller 31 and the second roller 32 can mutually transmit the target front wheel driving force. It is possible to control the traction transmission capacity between the first roller 31 and the second roller 32 to be the front / rear wheel target driving force distribution ratio by being pressed and contacted in the radial direction.

<Fail safe control when the roller overheats>
In addition to the above normal traction transmission capacity control (front and rear wheel drive force distribution control of a four-wheel drive vehicle), the transfer controller 111 executes the control program shown in FIG. Carry out.

In step S11, it is checked whether or not four-wheel drive (4WD) is required to distribute the driving force to the left and right front wheels (secondary drive wheels) 9L, 9R.
If four-wheel drive (4WD) is not requested but two-wheel drive (2WD) is required, control proceeds to step S12, and the driving force is distributed to the left and right front wheels (secondary drive wheels) 9L and 9R. The normal traction transmission capacity 0 control is performed so as not to be performed.
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 S11 that four-wheel drive (4WD) is being requested, it is determined in step S13 whether the hydraulic oil temperature TEMP is equal to or higher than the set oil temperature TEMPs for overheat determination.
Here, the set oil temperature TEMPs for overheat determination is a lower limit value of a high temperature region (overheat temperature region) where the outer

peripheral surfaces

31a and 32a of the first roller 31 and the second roller 32 cause surface separation at the mutual contact locations. .

When it is determined in step S13 that the hydraulic oil temperature TEMP is lower than the set oil temperature TEMPs, that is, the outer

peripheral surfaces

31a and 32a of the first roller 31 and the second roller 32 are not superheated so as not to cause surface separation at the mutual contact locations. When it is determined that the vehicle is in a state, fail-safe control for overheating countermeasures is not required, so control proceeds to step S14, and the above-described normal four-wheel drive (4WD) traction transmission capacity control (front and rear wheel drive force distribution) Control).

When it is determined in step S13 that the hydraulic oil temperature TEMP is equal to or higher than the set oil temperature TEMPs, that is, an overheat state in which the outer

peripheral surfaces

31a and 32a of the first roller 31 and the second roller 32 may cause surface peeling at the mutual contact locations. In the case where it is determined that this is, fail-safe control for countermeasure against overheating is necessary. Therefore, the control proceeds to step S15, and the following fail-safe control during overheating is performed.

In the overheat fail-safe control in step S15, the outer

peripheral surfaces

31a and 32a of the first roller 31 and the second roller 32 are mutually connected according to the hydraulic oil temperature TEMP, that is, to what extent the set oil temperature TEMPs is exceeded. The radial pressing force between the first roller 31 and the second roller 32 is reduced (including 0) to such an extent that surface peeling does not occur at the contact location.
Therefore, step S13 and step S15 are used as the roller radial pressing force correcting means (fail safe means) in this embodiment.

<Effect>
According to the transfer (driving force distribution device) 1 according to the first embodiment described above, the oil temperature sensor 116 for detecting the hydraulic oil temperature TEMP necessary for the above-described overheat fail-safe control is described above with reference to FIG. Since it is arranged on the street, the following effects can be obtained.
In other words, in this embodiment, the oil temperature sensor 116 is in contact with the outer peripheral surfaces of the first roller 31 and the second roller 32 in the rotational directions of the first roller 31 and the second roller 32 (respectively indicated by arrows in FIG. 5). Since the oil temperature detection end 116a is positioned behind the location (immediately in FIG. 5), the hydraulic oil temperature TEMP detected by the oil temperature sensor 116 is the location where the first and

second rollers

31 and 32 contact each other on the outer peripheral surface. As shown in FIG. 6, the control response of the fail-safe control described above with reference to FIG.

<Configuration>
FIG. 7 shows a traction force compensation control program for the driving force distribution device according to the second embodiment of the present invention.
Also in this embodiment, the configuration of the driving force distribution device (transfer) 1 including the arrangement of the oil temperature sensor 116 and the control system thereof are the same as those described above with reference to FIGS.

In the present embodiment, the transfer controller 111 in FIG. 1 executes the traction force compensation control program in FIG. 7 based on the hydraulic oil temperature TEMP detected by the oil temperature sensor 116 in the arrangement in FIG. 5, and is illustrated in FIG. Regardless of the change characteristics of the traction coefficient μ between the rollers (31, 32) due to the oil temperature TEMP, the traction force between the first roller 31 and the second roller 32 can correspond to the target front wheel driving force. As described above, the radial pressing force between the first roller 31 and the second roller 32 is corrected according to the change in the oil temperature TEMP.

The change characteristics of the traction coefficient μ between the rollers with respect to the oil temperature illustrated in FIG. 8 will be described. The traction coefficient μ between the rollers becomes the maximum when the oil temperature TEMP is a certain value, and the radial pressing force between the rollers and the like. If the conditions are the same, the traction force (traction transmission capacity) between the first roller 31 and the second roller 32 is maximized.
As the oil temperature TEMP decreases and increases away from the certain value, the traction force (traction transmission capacity) between the first roller 31 and the second roller 32 greatly decreases from the above maximum value.

In the normal four-wheel drive (4WD) traction transmission capacity control (front and rear wheel drive force distribution control) described above for the first embodiment, the oil temperature TEMP is exemplified as TEMPb (traction coefficient μ _b ) in FIG. Assuming that the temperature is a temperature, the target value for the radial pressing force between the first roller 31 and the second roller 32 capable of transmitting the target front wheel driving force is determined to contribute to the turning position control of the second roller 32. .

For this reason, if the oil temperature TEMP falls below the normal temperature TEMPb, for example, exceeding the range indicated by (−δ1) in FIG. 8 or becomes higher than the range indicated by (+ δ2) in FIG. Changes in μ make the traction force (traction transmission capacity) between the first roller 31 and the second roller 32 in an excessive or insufficient state that cannot be ignored relative to the target front wheel drive force, and the traction transmission capacity for four-wheel drive (4WD). Control (front / rear wheel driving force distribution control) cannot be performed as described above.

Therefore, in this embodiment, the traction force compensation control program of FIG. 7 is executed by the transfer controller 111 of FIG. 1, and the above problem is solved as follows.
First, in step S21, it is checked whether or not four-wheel drive (4WD) is required to distribute the driving force to the left and right front wheels (secondary drive wheels) 9L, 9R.
If two-wheel drive (2WD) is requested instead of requesting four-wheel drive (4WD), control proceeds to step S22, and the driving force is distributed to left and right front wheels (secondary drive wheels) 9L and 9R. The normal two-wheel drive (2WD) traction transmission capacity is controlled so as not to be performed.

If it is determined in step S21 that four-wheel drive (4WD) is being requested, in step S23, the hydraulic oil temperature TEMP deviates from the normal temperature TEMPb described above with reference to FIG. 8 within the range of (−δ1) to (+ δ2). The traction coefficient μ changes with the deviation from the normal temperature TEMPb, and the traction force (traction transmission capacity) between the first roller 31 and the second roller 32 is ignored with respect to the target front wheel drive force. Check whether or not the traction force compensation control is necessary because the traction transmission capacity control (front and rear wheel drive force distribution control) for four-wheel drive (4WD) can be performed as intended. .

If it is determined in step S23 that traction force compensation control is not required, control proceeds to step S24, and the above-described normal four-wheel drive (4WD) traction transmission capacity control (front and rear wheel drive force distribution control) is performed. To do.

When it is determined in step S23 that the hydraulic oil temperature TEMP has changed beyond the range of (−δ1) or (+ δ2) than the normal temperature TEMPb, that is, the change in the traction coefficient μ accompanying the deviation from the normal temperature TEMPb is large. The traction force (traction transmission capacity) between the first roller 31 and the second roller 32 is in excess or deficiency so that it cannot be ignored relative to the target front wheel drive force, and traction transmission capacity control for four-wheel drive (4WD) (front and rear wheel drive) Force distribution control) cannot be performed as intended and it is determined that traction force compensation control is necessary, the control proceeds to step S25, and the traction force change due to the deviation of the hydraulic oil temperature TEMP from the normal temperature TEMPb. Between the rollers determined by normal four-wheel drive (4WD) traction transmission capacity control (front and rear wheel drive force distribution control) Correcting the direction pressing force.
Therefore, Step S23 and Step S25 correspond to the inter-roller radial pressing force correcting means (traction force compensating means) in the present invention.

<Effect>
According to the transfer (driving force distribution device) 1 according to the second embodiment described above, the oil temperature sensor 116 for detecting the hydraulic oil temperature TEMP necessary for the traction force compensation control is the same as that described above with reference to FIG. In order to arrange in the same manner as in the first embodiment, and because the operating oil temperature TEMP at the location where the oil temperature sensor 116 is installed is close to the temperature of the contact surface between the outer peripheral surfaces of the first roller 31 and the second roller 32,
By increasing the control response of the traction force compensation control described above with reference to FIG. 7 and improving the control accuracy, the desired control effect can be exhibited.

<Configuration>
FIG. 9 shows an overheat fail-safe control and traction force compensation control program of the driving force distribution device according to the third embodiment of the present invention.
Also in this embodiment, the configuration of the driving force distribution device (transfer) 1 including the arrangement of the oil temperature sensor 116 and the control system thereof are the same as those described above with reference to FIGS.

In this embodiment, the transfer controller 111 in FIG. 1 executes the overheat fail-safe control and traction force compensation control program in FIG. 9 based on the hydraulic oil temperature TEMP detected by the oil temperature sensor 116 arranged in FIG. Thus, the overheat fail-safe control of the first embodiment described above with reference to FIG. 6 is performed, and the traction force compensation control of the second embodiment described above with reference to FIG. 7 is performed.

Steps S11 to S13 and Step S15 in FIG. 9 perform the same processing as the steps indicated by the same reference numerals in FIG. 6, and Steps S23 to S25 perform the same processing as the steps indicated by the same reference numerals in FIG. Shall.
If it is determined in step S11 that two-wheel drive (2WD) is required, in step S12, normal two-wheel drive that prevents the transfer force from being distributed to the left and right front wheels (secondary drive wheels) 9L and 9R in step S12 ( 2WD) for traction transmission capacity 0 control.

In step S11, it is determined that a four-wheel drive (4WD) is being requested, and in step S13, the hydraulic oil temperature TEMP is equal to or higher than the set oil temperature TEMPs illustrated in FIG. 8 (the outer peripheral surfaces of the first roller 31 and the second roller 32). When it is determined that 31a and 32a are in a high temperature region where surface peeling occurs at the mutual contact location), fail-safe control for overheating countermeasures is required, so in step S15, the hydraulic oil temperature TEMP is set in accordance with the hydraulic oil temperature TEMP. Depending on how much TEMPs are exceeded, the distance between the first roller 31 and the second roller 32 is such that the outer

peripheral surfaces

31a, 32a of the first roller 31 and the second roller 32 do not cause surface separation at the mutual contact points. Is reduced (including 0), and the overheat fail-safe control of the first embodiment described above with reference to FIG. 6 is performed.

peripheral surfaces

31a and 32a of the first roller 31 and the second roller 32 are not superheated so as not to cause surface separation at the mutual contact locations. In the case where the fail-safe control for overheating countermeasure is unnecessary, the traction force compensation control of the second embodiment described above with reference to FIG. 7 is performed in steps S23 to S25.

That is, when it is determined in step S23 that the hydraulic oil temperature TEMP is only deviated from the normal temperature TEMPb described above with reference to FIG. 8 within the range of (−δ1) to (+ δ2), that is, accompanying the deviation from the normal temperature TEMPb. The change in the traction coefficient μ is slight, and the traction force (traction transmission capacity) between the first roller 31 and the second roller 32 is negligible with respect to the target front wheel drive force. ) Traction transmission capacity control (front and rear wheel drive force distribution control) can be performed as intended, and if traction force compensation control is not required, normal traction drive capacity control for four-wheel drive (4WD) in step S24 (Front and rear wheel driving force distribution control) is performed.

However, when it is determined in step S23 that the hydraulic oil temperature TEMP has changed beyond the range of (−δ1) or (+ δ2) from the normal temperature TEMPb, that is, the change in the traction coefficient μ accompanying the deviation from the normal temperature TEMPb is large. The traction force (traction transmission capacity) between the first roller 31 and the second roller 32 is too much or insufficient to ignore the target front wheel driving force, and the traction transmission capacity control for four-wheel drive (4WD) (front and rear wheels) If the traction force compensation control is necessary and the traction force compensation control is necessary, the traction force change due to the deviation of the hydraulic oil temperature TEMP from the normal temperature TEMPb is eliminated in step S25 (traction traction). To compensate for the force), the radial squeezing between rollers determined by the normal traction drive capacity control for 4WD (4WD) (front and rear wheel drive force distribution control) Correcting the power, perform traction force compensation control in the second embodiment described above per FIG.

<Effect>
According to the transfer (driving force distribution device) 1 according to the third embodiment described above, in the above-described fail-safe control during overheating (steps S11 to S13 and step S15) and traction force compensation control (steps S23 to S25) The oil temperature sensor 116 for detecting the required hydraulic oil temperature TEMP is arranged in the same manner as in the first embodiment described above with reference to FIG. 5, and the hydraulic oil temperature TEMP at the installation location of the oil temperature sensor 116 is the first. Because it is close to the temperature of the contact surface between the outer peripheral surfaces of the roller 31 and the second roller 32,
The control response of the overheat fail-safe control (step S11 to step S13 and step S15) and traction force compensation control (step S23 to step S25) described above with reference to FIG. can do.

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 brought into contact with each other on their outer peripheral surfaces so as to be able to transmit power to each other, thereby distributing the driving force to the driven wheels and the radial pressing force between the first roller and the second roller. In the driving force distribution device using at least the temperature of the hydraulic oil as a control factor of the driving force distribution control, the driving force distribution control between the main driving wheel and the slave driving wheel is possible by adjusting
An oil temperature sensor for detecting the temperature of the hydraulic oil is arranged behind the mutual contact portion of the outer peripheral surfaces of the first roller and the second roller in the rotation direction of the first roller and the second roller. Driving force distribution device.
In the driving force distribution device according to claim 1,
The oil temperature sensor has an oil temperature detecting portion of the oil temperature sensor soaked in the hydraulic oil, and the outer peripheral surface mutual contact location of the first roller and the second roller, and the outer peripheral surface mutual contact location is a roller. A driving force distribution device, wherein the driving force distribution device is disposed so as to be positioned between a common contact surface in contact with the outer periphery of the first roller and the second roller at the rear in the rotation direction.
In the driving force distribution device according to claim 1 or 2,
Driving force distribution, characterized in that there is provided an inter-roller radial pressing force correcting means for correcting the radial pressing force between the first roller and the second roller according to the temperature of the hydraulic oil detected by the oil temperature sensor. apparatus.
In the driving force distribution device according to claim 3,
The inter-roller radial direction pressing force correcting means determines an abnormal increase in the outer peripheral surface temperature of the first roller and the second roller from the temperature of the hydraulic oil detected by the oil temperature sensor, and when the abnormality is determined, the first roller And a driving force distribution device that is fail-safe means for reducing the radial pressing force between the second rollers.
In the driving force distribution device according to claim 3,
The roller-to-roller radial direction pressing force correction means determines a traction transmission characteristic change between the first roller and the second roller from the temperature of the hydraulic oil detected by the oil temperature sensor, and converts the traction transmission characteristic to a traction force due to the traction transmission characteristic change. A driving force distribution device that is a traction force compensation unit that corrects a radial pressing force between the first roller and the second roller so as to eliminate the influence of.
In the driving force distribution device according to claim 3,
The inter-roller radial direction pressing force correcting means determines an abnormal increase in the outer peripheral surface temperature of the first roller and the second roller from the temperature of the hydraulic oil detected by the oil temperature sensor, and when the abnormality is determined, the first roller And function as a fail-safe means for reducing the radial pressing force between the second rollers, while the detected temperature of the hydraulic oil does not show an abnormal increase in the outer peripheral surface temperature of the first roller and the second roller. The traction transmission characteristic change between the first roller and the second roller is determined from the temperature of the first roller, and the radial pressing force between the first roller and the second roller is removed so that the traction force change due to the traction transmission characteristic change is eliminated. A driving force distribution device which functions as a traction force compensation means for correcting.