JPH1044819A - Vehicular differential-limiting controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate an appropriate differential-limiting torque corresponding to the running conditions of a vehicle or road surfaces on which the vehicle travels or even a larger differential-limiting torque efficiently with a simple, light and compact device constituted of a reduced number of component parts without causing an increase in its size through the employment of an existing device in common for its use to the utmost. SOLUTION: A rear-wheel differential-limiting torque generator part 19 comprises a compound planetary-gear type differential-limiting device for transmitting driving force to a first sun gear 60 and outputting it through a second sun gear 61 to a left driving axle 20 and through a carrier 48 to a right driving axle 23, and has a hydraulic multiple disk clutch for variably controlling frictional force generated between the left driving axle 20 as one output side and the carrier 48 as the other output side corresponding to road-surface conditions and the running conditions of the vehicle. The compound planetary-gear type differential-limiting device part generates differential-limiting torque, and in addition a differential-limiting torque increase/ compensation controller part 35 ascertains road-surface conditions and the running conditions of the vehicle based on input signals and, if necessary, accordingly operates the hydraulic multiple disk clutch to optimally increase the generated differential- limiting torque for compensation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential limiting control device for a vehicle which generates differential limiting torque for right and left wheels at an appropriate value.

[0002]

2. Description of the Related Art As a differential device used for a drive shaft of a vehicle, for example, as shown in FIG. 15, a rotatable differential case in which a crown gear 2 meshing with a drive pinion 1 for transmitting a driving force is fixed to the outside. 3, the ends of the left and right axle shafts 4, 5 on the same axis are rotatably inserted, and a pinion shaft 6 is fixedly supported between the left and right axle shafts 4, 5. Side gears 7 and 8 are fixedly mounted on the tip of the pinion 5, and the pinion shaft 6 has pinions 9 and 1 meshed with the side gears 7 and 8.
0 is rotatably supported.

[0003] In such a differential device, when one wheel slips or slips on a road surface having large unevenness, a steep slope, or running on a split μ road, etc., it is necessary to apply a force to the gripping wheel. Since the transmission of the driving force is lost, the driving force of the wheel that is about to slip is moved to the wheel on the gripping side to limit the differential (to generate the differential limiting torque). 2. Description of the Related Art Differential limit control devices for improving securing, running stability and athletic performance have been increasingly used.

Various techniques have been shown for such a differential limit control device, and the present applicant has proposed a differential limit control device shown in FIG. 16 in Japanese Patent Application Laid-Open No. 2-261947. . In this differential limiting control device, a wet hydraulic multi-plate clutch 11 is provided between a differential case 3 of the above-described differential device and one side gear (left wheel side gear 2). Numeral 11 indicates that the frictional force is variably controlled depending on the running state of the vehicle and the running road surface, so that a differential limiting torque of an appropriate value can be generated. Is transmitted from the left wheel side to the differential case 3 on the low rotation side, and when slippage occurs on the right wheel side, torque is transmitted from the differential case 3 side to the left wheel side.

In this differential limiting control device, the hydraulic multiple disc clutch for generating the differential limiting torque is arranged only on the left wheel side. Compared with the control device, the width in the left-right direction can be significantly reduced, and the number of mechanisms and components for pressing the hydraulic multi-plate clutch can be reduced, so that the differential limit control device can be made more compact. Weight reduction and cost reduction can be achieved.

[0006]

However, even in the above-mentioned differential limit control device, if it is intended to secure a large differential limit torque, the number of multi-plate clutches must be increased or the hydraulic multi-plate clutch must be operated. A large hydraulic pressure or the like is required, and particularly in a vehicle with a large output, the differential limiting control device tends to be slightly larger. For this reason, a differential limiting control device that can generate a differential limiting torque of an appropriate value depending on the traveling state of the vehicle and the road surface, and that can effectively generate a large differential limiting torque without increasing the size of the device is desired. I have.

The present invention has been made in view of the above circumstances, and has a simple structure, a small number of parts, a light weight and a compact size. An object of the present invention is to provide a vehicle differential limit control device capable of generating a differential limit torque having an appropriate value and effectively generating a large differential limit torque without increasing the size of the device.

[0008]

According to a first aspect of the present invention, there is provided a differential limiting control apparatus for a vehicle according to the present invention, wherein at least one of a front wheel side and a rear wheel side has a first driving force input side. The first sun gear meshes with the first pinion to form a first gear train, and the second sun gear on the output side of one of the left wheel side and the right wheel side is a second gear integrated with the first pinion. The second gear train is formed by meshing with the pinion.
The second pinion is supported by the other output side carrier,
A frictional force obtained by applying a difference between a thrust load acting on a gear mesh point of the first gear train and the second gear train to one end face of the first and second pinions; And the frictional force obtained by applying the combined force of the separation load and the tangential load acting on the gear meshing point of the second gear train to the gear mesh point of the second gear train on the shaft support portions of the first and second pinions. Friction that generates a differential limiting torque proportional to the input torque between the wheels and that variably generates a frictional force between the one output side and the other output side according to a road surface state and a running state It is rotatably connected via a connecting member.

According to a second aspect of the present invention, there is provided a differential limiting control apparatus for a vehicle according to the first aspect of the present invention, wherein the frictional connection member responds to a road surface state and a running state. The frictional force variably generated is increased when the rotational speed difference between the left and right wheels is equal to or greater than a predetermined reference value, and is increased when the vehicle speed and the engine load are higher when the difference is lower than the reference value.

According to a third aspect of the present invention, there is provided a differential limiting control apparatus for a vehicle according to the first or second aspect of the present invention, wherein the frictional connection member is adapted to determine a road surface condition. It is formed by a hydraulic multi-plate clutch that operates with a pressing force that is variably controlled in accordance with the running state.

According to a fourth aspect of the present invention, there is provided a differential limiting control apparatus for a vehicle according to the third aspect of the present invention, wherein the pressing force is one of the hydraulic multiple disc clutches. It is given from the side.

According to a fifth aspect of the present invention, there is provided a differential limiting control apparatus for a vehicle according to any one of the first, second, and third aspects. , Supplied from a center differential device.

Further, according to a sixth aspect of the present invention, there is provided the differential limiting control apparatus for a vehicle according to the fifth aspect, wherein the center differential device is provided with a third sun gear on the input side. Is meshed with a third pinion to form a third gear train, and a fourth sun gear on the output side of one of the front wheel side and the rear wheel side is connected to a fourth pinion integrated with the third pinion. A fourth gear train is formed by meshing, and the third and fourth pinions are pivotally supported by the other output-side carrier, and a gear mesh between the third gear train and the fourth gear train is formed. A frictional force obtained by applying a difference in a thrust load acting on a point to one end face of the third and fourth pinions, and a frictional force acting on a gear mesh point between the third gear train and the fourth gear train. The combined force of the separation load and the tangential load to the third and fourth pinions. In the friction force obtainable by acting on the journal section, which is constituted so as to generate a differential limiting torque proportional to the input torque between the front and rear wheels.

That is, in the vehicle differential limiting control device according to the first aspect of the invention, at least one of the driving forces on the front wheel side and the rear wheel side is output on one of the output side on the left wheel side and the right wheel side and on the other side. Power is distributed to the output side. For example, the one output side is set to the left wheel side, and the other output side is set to the right wheel side, and the vehicle travels by distributing power to the left and right wheels. When the friction coefficient of the road surface on which the left wheel and the right wheel are in contact with each other is greatly different between the left and right wheels, when the left wheel and the right wheel rotate differentially, the gear mesh between the first gear train and the second gear train. The difference between the thrust loads acting on the points
The frictional force acting on one end face of the second pinion and the combined force of the separation load and the tangential load acting on the gear mesh point of the first gear train and the second gear train are the first force. ,
The frictional force generated by acting on the bearing portion of the second pinion increases in proportion to the input torque, and the frictional force causes the differential limiting torque in the direction opposite to the rotation of the first and second pinions. Occurs. This differential limiting torque is controlled so as to move to the right wheel side when the left wheel slips and to the left wheel side when the rotation speed of the right wheel is large, so as to prevent slipping. Then, in addition to the differential limiting torque, a frictional force is generated as a differential limiting torque between the one output side and the other output side by the friction connecting member according to the road surface state and the traveling state.

The vehicle differential limiting control device according to the second aspect of the present invention is the vehicle differential limiting control device according to the first aspect, wherein the left and right wheels are driven on a rough road having different road surface friction coefficients. When one of the wheels slips and the rotational speed difference between the left and right wheels becomes equal to or greater than a predetermined reference value, the frictional force generated by the frictional connection member increases and the differential limiting torque increases. On the other hand, when the value is lower than the reference value, at a high speed when the vehicle speed is high, or when starting or accelerating under a large engine load, the larger the value is, the larger the frictional force becomes and the larger the differential limiting torque is generated.

According to a third aspect of the present invention, there is provided a differential limiting control apparatus for a vehicle according to the first or second aspect, wherein the frictional connecting member is formed by a hydraulic multiple disc clutch. The pressing force on the hydraulic multi-plate clutch is variably controlled according to the road surface state and the running state to control the generated frictional force, that is, the amount of increase in the differential limiting torque.

Further, the vehicle differential limiting control device according to the fourth aspect of the present invention is the vehicle differential limiting control device according to the third aspect, wherein a pressing force is applied from one side of the hydraulic multiple disc clutch. In addition, the aim is to further reduce the weight and size of the device, simplify the device, and reduce the number of parts.

According to a fifth aspect of the present invention, there is provided a differential limiting control apparatus for a vehicle according to any one of the first, second, and third aspects, wherein the engine is controlled by a center differential device. The driving force of the front wheel and the rear wheel distributed before and after the front and rear wheels is further limited by the differential limiting control device to the right and left while being differentially limited. Distributed.

Further, the vehicle differential limiting control device according to claim 6 is the vehicle differential limiting control device according to claim 5, wherein the center differential device is configured such that an input from an engine side is connected to a front wheel side. Power is distributed to either the output side of the rear wheel and the other output side.For example, the one output side is set to the rear wheel side, and the other output side is set to the front wheel side, and power is distributed to front and rear wheels. I do. When the front and rear wheels differentially rotate in a case where the friction coefficient of the road surface where the front wheels and the rear wheels contact the ground is significantly different between the front and rear, the third gear train and the fourth
The difference between the thrust load acting on the gear mesh point of the gear train of the third gear train and the friction force generated by acting on one end face of the third and fourth pinions, and the difference between the third gear train and the fourth gear train. The combined force of the separation load and the tangential load acting on the gear meshing point and the frictional force generated by acting on the bearing portions of the third and fourth pinions increase in proportion to the input torque, and these frictional forces are increased. As a result, differential limiting torque is generated in the direction opposite to the rotation of the third and fourth pinions. This differential limiting torque is controlled so as to move to the rear wheel side when the front wheel slips, and to the front wheel side when the rotation speed of the rear wheel is high, so as to prevent slipping.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 12 show a first embodiment of the present invention. FIG. 1 is an explanatory view showing an overall schematic configuration of a differential limiting control device for an FR vehicle. FIG. 2 is an enlarged sectional view of a differential limiting torque generating section. , FIG. 3 is a schematic diagram of each part for explaining the differential function, FIG. 4 is an operation explanatory diagram when the first sun gear is fixed,
FIG. 5 is an explanatory diagram of an operation when the second sun gear is fixed, and FIG.
Is a schematic diagram of each part for explaining a power distribution function and a differential limiting function, FIG. 7 is an explanatory diagram of a load generated by each gear, and FIG. 8 is an explanatory diagram of a case where a right wheel speed is larger than a left wheel speed. ,
9 is an explanatory diagram when the right wheel rotational speed is smaller than the left wheel rotational speed, FIG. 10 is a functional block diagram of the differential limiting torque increase correction control unit, FIG. 11 is a configuration explanatory diagram of the hydraulic control device,
FIG. 12 is a flowchart of the differential correction torque increase correction control. In the first embodiment of the present invention, an FR (front engine / rear drive) vehicle is provided with a differential limit generating unit.

In FIG. 1, reference numeral 15 denotes an engine disposed at the front of the vehicle. A transmission 16 is connected to the rear of the engine 15. The driving force of the engine 15 is transmitted from the transmission 16 to the propeller shaft 17, the drive The torque is input to the rear wheel differential limiting torque generating unit 19 via the pinion 18, and from the rear wheel differential limiting torque generating unit 19, the left drive shaft 20,
Right drive shaft 2 to left rear wheel 22 via left axle shaft 21
3. The power is transmitted to the right rear wheel 25 via the right axle shaft 24.

A throttle body 27 communicating with an intake manifold 26 of the engine 15 is provided with a throttle opening sensor 28 for detecting the opening (throttle opening α) of a throttle valve (not shown).
The transmission 16 is provided with a vehicle speed sensor 29 for detecting a rear wheel output shaft rotation speed as a vehicle speed V.

Further, a steering angle sensor 31 for detecting a steering angle θ is provided on a steering column of the steering wheel 30.
The housing of the left rear wheel 22 is provided with a left rear wheel rotation speed sensor 32 for detecting a left rear wheel rotation speed NLR, and the housing of the right rear wheel 25 is provided with a right rear wheel rotation speed NRR. A right rear wheel speed sensor 33 is attached to each.

In addition, an acceleration sensor 34 for detecting the acceleration g of the vehicle is provided, and each of these sensors is connected to a differential limit torque increase correction control unit 35 for performing a differential limit torque increase correction control. Also, a control unit 3 such as a TCU (transmission control unit) or an ECU (engine control unit).
6, a gear position signal e is extracted and input to the differential limiting torque increase correction control unit 35.

The differential limiting torque increase correction control unit 35
Determines the road surface state and the running state based on each input signal,
The hydraulic control device 37 determines the optimum increment of the differential limiting torque generated by the differential limiting torque generating portion 19 and outputs a signal to the hydraulic control device 37. , A hydraulic pressure is applied to the differential limiting torque generating unit 19 through a hydraulic line 38.

Next, the differential limiting torque generator 19 will be described in detail with reference to FIG. The drive pinion 18 and the rear wheel differential limiting torque generating section 19 are accommodated in a rear differential carrier 40, and a rear end of the rear differential carrier 40 has a cover 41.
Covered with.

In the drive pinion 18, a shaft 18a connected to the propeller shaft 17 is rotatably supported by a bearing 42 in the rear differential carrier 40.

The left drive shaft 20 is rotatably provided through a left side retainer 43L attached to the rear differential carrier 40. The right drive shaft 23 is coaxial with the left drive shaft 20. The right side retainer 43R attached to the differential carrier 40 is rotatably provided through the right side retainer 43R. The through holes of the respective side retainers 43L, 43R are sealed by oil seals 44, 44.

A left differential case 45L is rotatably fitted around the left drive shaft 20.
The left drive shaft 20 and the left differential case 45L are mounted on the left side retainer 43L by a bearing 4L.
6 rotatably supported.

The above left differential case 45L
One end (left end) of the right differential case 45R and a crown gear 47 meshed with the drive pinion 18 are both centered on the center of rotation and fixed, and are fixed to the right differential case 45R.
The other end of the right drive shaft 23 is rotatably fitted to the outer periphery of the right drive shaft 23, and the right drive shaft 23 and the right differential case 45 R are connected to the right side retainer 4.
The 3R is rotatably supported via a bearing 46. That is, it is composed of the left differential case 45L and the right differential case 45R,
A differential case 45 to which the crown gear 47 is attached is rotatably held in the rear differential carrier 40.

In the differential case 45, a carrier 48 whose left portion is formed in a cylindrical shape as a clutch drum 48a is rotatably disposed. The portion of the clutch drum 48a is provided with a bush 49 outside.
Through the left differential case 45L.

The left drive shaft 20 and the right drive shaft 23 are inserted into the carrier 48, and the carrier 48 is spline-coupled to the tip of the right drive shaft 23.

A hub 50 is spline-connected to a portion of the left drive shaft 20 facing the inner surface of the clutch drum 48a via a washer 51 between the hub 50 and the inner surface of the left differential case 45L.

At the right end of the clutch drum 48a, a retaining plate 52 is provided. To the left of the retaining plate 52, a drive plate 53a attached to the outer surface of the hub 50 and the clutch drum 4
A plurality of driven plates 53b attached to the inner surface 8a are alternately arranged. A snap ring 54 is provided at an end of each of the plurality of plates 53, and these plates 53 are securely supported.

The plurality of plates 53 are connected to the hydraulic piston 5
5 to generate a frictional force. The hydraulic piston 55 is provided on the left differential case 45L side and can freely press the plurality of plates 53 via a thrust bearing 55d. A pressing piston 55a rotatable with the left differential case 45L and a hydraulic chamber piston 55b built in the left side retainer 43L and operated by directly receiving hydraulic pressure in the hydraulic chamber 56 are connected via a thrust bearing 55c. It is configured.

The pressing piston 55a is connected to a return spring 5, one end of which is supported by a snap ring 57 provided on the inner surface of the rear differential carrier 40.
8 urges in the hydraulic chamber 56 direction.

The hydraulic chamber 56 is adapted to receive hydraulic pressure from the hydraulic pipeline 38. The hydraulic chamber piston 55b facing the hydraulic chamber 56 has seal rings 59a, 59b on its inner and outer circumferences. Is provided.

That is, as described above, the first embodiment of the present invention employs a hydraulic multi-plate clutch as the frictional connection member.

On the other hand, a large-diameter first sun gear 60 is spline-coupled to the inside of the right differential case 45R, and a small-diameter second sun gear 61 is spline-coupled to the tip of the left drive shaft 20. The first
The first sun gear 60 meshes with a small diameter first pinion 62 to form a first gear train, and the second sun gear 61 meshes with a large diameter second pinion 63 to form a second gear train. Have been. A washer 64 is interposed between the end face of the first sun gear 60 and the carrier 48.

The first pinion 62 and the second pinion 63 are formed integrally with a pinion member 65,
A plurality (for example, three) of the pinion members 65 are rotatably supported by respective planetary pins 66 fixed to the carrier 48. At both ends of the pinion member 65, washers 67 for receiving a thrust load are interposed between the pinion member 65 and the carrier 48.

That is, the rear wheel differential limiting torque generating unit 19 transmits the driving force from the drive pinion 18 to the first sun gear 60 via the crown gear 47 and the differential case 45, and Sun gear 6
1 to the left drive shaft 20 and a composite planetary gear type differential limiting device that outputs from the carrier 48 to the right drive shaft 23. The left drive shaft 23 on one output side and the other The structure is such that a hydraulic multi-plate clutch in which the frictional force generated according to the road surface condition and the running condition is varied is interposed between the carrier and the output side. Then, in addition to the differential limiting torque proportional to the input torque generated by the composite planetary gear type differential limiting device, the hydraulic multiple disc clutch increases and corrects the differential limiting torque as necessary to optimize the differential limiting torque. Is generated.

The composite planetary gear type differential limiting device includes the first and second sun gears 60 and 61 and the first and second pinions 62 arranged in plurals around the sun gears 60 and 61. , 63 have a differential function by appropriately setting the number of teeth.

The first and second sun gears 60, 6
By appropriately setting the pitch circle radii of engagement between the first pinion 62 and the first and second pinions 62 and 63, the reference torque distribution has a function of 50:50 left and right equal torque distribution.

Further, the first and second sun gears 60, 6
1 and the first and second pinions 62 and 63 are, for example, helical gears, and the first gear train and the second gear train have different torsion angles so that the thrust load is not canceled out. A load is left to cause friction torque between the pinion end faces, and a combined force of separation and tangential load acts on the surfaces of the first and second pinions 62 and 63 and the surface of the planetary pin 66 by engagement to generate friction torque. To obtain a differential limiting torque proportional to the input torque to provide a differential limiting function.

Next, the differential function will be described with reference to FIGS. 3, 4, and 5. First, when the first sun gear 60 is fixed as shown in FIG. 4, (arc KF) = (arc CF)-(arc CK) (1) is established on the circumference of the radius rs2, as shown in FIG. When the second sun gear 61 is fixed, (arc ZF) = (arc BF)-(arc BZ) (2) is established on the circumference of the radius rs1.

Here, the first and second sun gears 60, 61
Angular velocities ωs1, ωs2, meshing pitch circle radius rs1
, Rs2, the angular velocities ωp1, ωp2 of the first and second pinions 62, 63, the engagement pitch circle radii rp1, rp2
, The angular velocity ωc of the carrier 48, the expression (1) is
.omega.s2.rs2 =-. omega.p2.rp2 + .omega.c.rs2... (3), and the equation (2) is expressed as .omega.s1 .rs1 =-. omega.p1 .rp1 + .omega.c .rs1.

Therefore, the first and second pinions 62, 63
Is integral and ωp1 = ωp2. Therefore, rearranging the above equations (3) and (4), ωc · (rs2−rs1 · rp2 / rp1) = ωs2 · rs2−ωs1 · rs1 · rp2 / rp1 ( 5) holds.

Here, the angular velocity ωs of the first sun gear 60
1 is the input rotational speed Ni, the angular velocity ωc of the carrier 48 is the right rear wheel rotational speed NR, the angular velocity ωs2 of the second sun gear 61 is the left rear wheel rotational speed NL, and the meshing pitch circle of the first and second sun gears 60, 61. Radius rs1, rs2 and engagement pitch circle radii rp1, r of first and second pinions 62, 63
If p2 is replaced by the number of teeth Zs1, Zs2, Zp1, Zp2, the above equation (5) becomes
NR. (Zs2-Zs1.Zp2 / Zp1) = NL.Zs2-Ni.Zs1.Zp2 / Zp1 (5) '

Then, the above-mentioned number of teeth is defined as Zp1 = 24, Z
If p2 = 24, Zs1 = 30, and Zs2 = 15, the relationship becomes NL + NR = 2Ni. When Ni ≠ 0, NL>Ni> NR,
Alternatively, NR>Ni> NL holds, and the right rear wheel rotational speed N
Both R and the rear left wheel rotational speed NL have the same rotational direction, and a differential is established.

Next, the equal torque distribution function will be described with reference to FIGS. 6, 7, 8, and 9. First sun gear 60
Is the input torque of Ti, and the meshing pitch circle radius is rs
1, the torque on the right rear wheel side of the carrier 48 is TR, and the first and second
The radius of the meshing pitch circle of the pinions 62 and 63 is rp1
, Rp2, and the left rear wheel torque of the second sun gear 61 to T
L, and the meshing pitch circle radius is rs2. Ti = TR + TL (6) rs1 + rp1 = rs2 + rp2 (7)

The tangential load P acting on the meshing point between the first sun gear 60 and the first pinion 62 includes the tangential load P 1 acting on the carrier 48 and the second sun gear 6.
It is equal to the sum of the tangential load P2 acting on the meshing point between the first and second pinions 63. P = Ti / rs1 P1 = TR / (rs1 + rp1) P2 = TL / rs2 Ti / rs1 = {(TR / (rs1 + rp1)} + TL / rs2 (8) Substituting into equation 8) and rearranging, TR = (1−rp1 · rs2 / rs1 · rp2) · Ti (9) TL = (rp1 · rs2 / rs1 · rp2) · Ti (10) Therefore, the first and second sun gears 60, 6
It can be seen that the reference torque distribution of the right rear wheel torque TR and the left rear wheel torque TL can be set freely by the engagement pitch circle radii of the first and second pinions 62, 63.

Then, each of the meshing pitch circle radii rs
1, rs2, rp1, rp2 is the number of teeth Zs1, Z
s2, Zp1, Zp2, and substitute the above-mentioned number of teeth for each of these numbers of teeth (Zp1 = 24, Zp2 = 24, Zs
1 = 30, Zs2 = 15), and TR = 0.5 · Ti TL = 0.5 · Ti Therefore, the front and rear wheel torque distribution is approximately 50 to 50, and the reference torque distribution can be sufficiently set to the equal torque distribution.

Further, the differential limiting function will be described.
The first and second sun gears 60, 61 and the first,
The second pinions 62 and 63 are helical gears having a predetermined torsion angle, and the first and second pinions 6
2 and 63, the planetary pins 66 without canceling the thrust load acting on the meshing point with the first and second sun gears 60 and 61.
And a sliding frictional force is generated at both end surfaces (washers 67). Further, the combined force of the separation load and the tangential load acting on the mesh point of the first gear train and the second gear train is applied to the first and second pinions 62 and 63 and the planetary pin 66. Then, rolling frictional force is generated. These frictional forces produce a friction torque in the opposite direction to the pinion rotation and proportional to the input torque, that is, a differential limiting torque.

Here, the right wheel speed NR and the left wheel speed NL
The rotation direction of the pinion changes depending on the magnitude relation between the rotation of the pinion and the degree of application of the differential limiting torque. As a result, when turning with NR> NL and slipping on the right wheel, NR <NL
When the left wheel slips, the power distribution between the left and right wheels is automatically controlled to be different according to the difference in the operation of the differential limiting torque.

Therefore, based on FIGS. 6, 7 and 8, NR> N
The case of L will be described. Under this condition, as shown in FIG.
When i is input, the first and second pinions 62 and 63
Rotate in the same direction, and the second sun gear 61 and the carrier 4
8 also rotates in the same direction. Therefore, the pinion-side friction torque Tf acts in a clockwise direction opposite to that of the pinion.

Here, the torque and radius of each part are determined in the same manner as described above. Further, the tangential load P, the separation load Fs1, the thrust load Ft1 acting on the tooth surfaces of the first sun gear 60 and the first pinion 62 of the first gear train, and the second gear train of the second gear train.
, A tangential load P2, a separation load Fs2, and a thrust load Ft2 acting on the tooth surfaces of the sun gear 61 and the second pinion 63.

The friction coefficient μ1 between the pinion member 65 and the planetary pin 66, the washer 67
, The friction torque Tf, the pinion inner radius re, the outer radius rd of the washer 67, and the number n of contact surfaces. Module m of first pinion 62
1, the torsion angle β1, the pressure angle α1, the module m2 of the second pinion 63, the torsion angle β2, and the pressure angle α2.

Then, Fs1 = P · tanα1 / cosβ1 Ft1 = P · tanβ1 is established, and the resultant force N acting on the planetary pin 66 side is obtained.
p1 is as follows. ^{Np1 = (P 2 + Fs1 2} ) 1/2 = P {1+ (tanα1 / cosβ1) 2} 1/2 ... (11) In the same manner, and established Fs2 = P2 · tanα2 / cosβ2 Ft2 = P2 · tanβ2, The resultant force Np2 acting on the planetarin pin 66 is as follows. Np2 = (P2 ² + Fs2 ² ) ^1/2 = P ² ｛1+ (tan α ² / cos β ² ) ² ｝ ^1/2 (12) Further, the residual thrust force ΔFt generated in the first and second pinions 62 and 63 is as follows. become that way. ΔFt = Ft2−Ft1 = P2 · tanβ2−P · tanβ1 (13) Accordingly, the friction torque Tf is determined by the two resultant forces Np1 and Np2.
And the sum of the frictional force due to the residual thrust force ΔFt and the frictional force due to the residual thrust force ΔFt. Tf = μ 1 · re · (Np 1 + Np 2) + ΔFt · μ 2 · n · 2/3 · {(rd ³ −re ³ ) / (rd ² −re ² )} (14) Next, the first and second pinions The torque balance formula at 62 and 63 is as follows. Tf + P · rp1 = P2 · rp2 (15) Further, when the friction torque Tf is added to the above equation (10),
It looks like this: TL = Ti (rp1 · rs2 / rs1 · rp2) + Tf · rs2 / rp2 (16) Here, as described above, each of the meshing pitch circle radii r
s1, rs2, rp1, rp2 are replaced by the number of teeth Zs1,
Zs2, Zp1, and Zp2, and substitute the above-mentioned number of teeth for each of these numbers of teeth (Zp1 = 24, Zp2 = 24, Zp2).
s1 = 30, Zs2 = 15), and the above equation (16) gives: TL = 0.5Ti + 0.625Tf (17)

Further, Ti = TR + TL, and the following equation (16) is substituted into this and arranged as follows. TR = Ti (1−rp1 · rs2 / rs1 · rp2) −Ti · rs2 / rp2 (18) Further, each tooth number is replaced by Zs1, Zs2, Zp1, Zp2, and the above tooth number is substituted for each tooth number. Then, the above equation (18) becomes TR = 0.5Ti−0.625Tf (19).

Here, if μ1 = 0 and μ2 = 0, Tf =
It is 0, and the values of the left and right wheel torques TL and TR indicate the same reference torque distribution as the equation for the above-described equal torque distribution function.

Thus, under such conditions, the friction torque T
It can be seen that a differential limiting torque Tf · rs2 / rp2 corresponding to f is generated. Then, the distribution of the left and right wheel torques TL and TR is changed such that the left wheel side is larger and the right wheel side is smaller by the differential limiting torque. Also, the friction torque Tf
Forces Np1, Np2, and residual thrust force ΔFt
Has an input torque proportional differential limiting function because it is proportional to the input torque.

On the other hand, the residual thrust force ΔFt is determined by the difference between the twist angles β 1 and β 2 of the first and second pinions 62 and 63.
The friction coefficient μ1 can be changed by using a needle bearing, a bush or the like between the pinion member 65 and the planetary pin 66. Thus, the value of the differential limiting torque together with the friction torque Tf can be set to various values.

Further, the above equations (17) and (19) are
In consideration of the torque Tc generated by the hydraulic multiple disc clutch, the torque Tc acts in a direction to eliminate the speed difference between the left and right wheels, and is as follows: TL = 0.5Ti + 0.625Tf + Tc (20) TR = 0.5Ti−0.625Tf−Tc (21) The differential limiting torque represented by the above equations (20) and (21) is a differential limiting torque generated by the rear wheel differential limiting torque generating unit 19. is there.

Next, the case where NL> NR will be described. Under this condition, the condition is as shown in FIG. 9, and the first and second pinions 62 and 63 revolve while rotating in the clockwise direction opposite to the first sun gear 60, and the friction torque Tf acts counterclockwise. . Therefore, the first and second pinions 62,
The balance formula of the torque in 63 is as follows. Tf + P2 · rs2 = P · rp1 (22) Then, when calculated in the same manner as described above, the left and right wheel torques TL, T
R is as follows. TR = Ti (1−rp1 · rs2 / rs1 · rs2) + Tf · rs2 / rp2 (23) TR = 0.5Ti + 0.625Tf (24) TL = Ti (rp1 · rs2 / rs1 · rs2) −Tf · rs2 / Rp2 (25) TL = 0.5Ti-0.625Tf (26) Accordingly, even under this condition, the same differential limiting torque, Tf · rs
2 / rp2 occurs. On the other hand, in this case, contrary to the above, the torque is distributed so that the left wheel side is smaller and the right wheel side is larger by the differential limiting torque.

Further, the above equations (24) and (26) are
In consideration of the torque Tc generated by the hydraulic multi-plate clutch, the torque Tc acts in a direction to eliminate the speed difference between the left and right wheels, and is as follows: TR = 0.5Ti + 0.625Tf + Tc (27) TL = 0.5Ti−0.625Tf−Tc (28) The differential limiting torque represented by the above equations (27) and (28) is the differential limiting torque generated by the rear wheel differential limiting torque generating unit 19. is there.

Next, regarding the hydraulic control device 37,
This will be described with reference to FIG. The discharge pressure of an oil pump 71 driven by a motor 70 is regulated by a regulator valve 72 to generate a predetermined operating oil pressure and a lubricating oil pressure. It is connected to the hydraulic chamber 56 side of the hydraulic multi-plate clutch via a conduit 38.

The oil passage 73 is connected to the pilot valve 7.
5. The oil passage 76 communicates with the duty solenoid valve 77 and the control side of the clutch control valve 74.

The duty signal from the differential limiting torque increase correction control unit 35 is output to the duty solenoid valve 77 to generate a duty pressure. By operating the clutch control valve 74 at this duty pressure,
The clutch hydraulic pressure of the hydraulic multi-plate clutch is controlled.

Further, as shown in FIG. 11, the differential limiting torque increase correction controller 35 includes a rear wheel rotational speed difference detector 8 as shown in FIG.
1. Rear wheel slip determination unit 82, slip rear wheel clutch oil pressure setting unit 83, non-slip rear wheel clutch oil pressure setting unit 84
And a rear-wheel-side duty signal conversion / output unit 85, which executes the program shown in FIG.

The rear wheel rotational speed difference detecting section 81 receives signals from the left rear wheel rotational speed sensor 32 and the right rear wheel rotational speed sensor 33 and calculates a rotational speed difference.
Assuming that the left rear wheel rotation speed is NL and the right rear wheel rotation speed is NR, the rotation speed difference ΔN is calculated by ΔN = | NL−NR |, and this rotation speed difference ΔN is output to the rear wheel slip determination unit 82. You.

The rear wheel slip determining section 82 determines whether the rotational speed difference ΔN from the rear wheel rotational speed difference detecting section 81 is equal to or greater than a preset reference value Nc, and determines the rotational speed between the left and right wheels. If the difference ΔN is large and is equal to or larger than the reference value, it is determined that the vehicle is in a slip state, and the slip rear wheel clutch oil pressure setting unit 8
When the rotational speed difference ΔN between the left and right wheels is small and smaller than the reference value, it is determined that the vehicle is in the non-slip state and is output to the non-slip rear wheel clutch hydraulic pressure setting section 84.

The slip rear wheel clutch oil pressure setting unit 83
Is operated based on an output signal (slip state) from the rear wheel slip determination unit 82, and based on a steering angle θ from the steering angle sensor 31 based on a map set in advance through experiments, theoretical calculations, and the like. A high clutch oil pressure to be searched and corrected for increase is set and output to the rear wheel side duty signal conversion output unit 85.

The non-slip rear wheel clutch oil pressure setting section 84 is operated by an output signal (non-slip state) from the rear wheel slip determination section 82 to set a clutch oil pressure to be increased in the non-slip state. The output is output to the rear wheel side duty signal conversion output unit 85. Here, the non-slip rear wheel clutch hydraulic pressure setting unit 8
The clutch oil pressure set at 4 is a map based on the vehicle speed V from the vehicle speed sensor 29 and the throttle opening α of the throttle opening sensor 28 (which is set in advance through experiments, theoretical calculations, etc. The gear position e is further increased and corrected at the lower gear, the decrease is corrected by the steering angle θ from the steering angle sensor 31, and the acceleration sensor 34 is corrected. Is set by correcting the increase with the acceleration g from.

The rear wheel side duty signal conversion output section 85
The duty ratio of the hydraulic signal from the slip rear wheel clutch oil pressure setting unit 83 or the non-slip rear wheel clutch oil pressure setting unit 84 is converted and output to the rear wheel duty solenoid valve 77 of the hydraulic control device 37. Has become.

As shown in the flowchart of FIG. 12, the program executed by the differential limiting torque increase correction control unit 35 first includes a step (hereinafter abbreviated as "S") 101 at the left rear wheel. Based on the left rear wheel rotation speed NL from the rotation speed sensor 32 and the right rear wheel rotation speed NR from the right rear wheel rotation speed sensor 33, a rotation speed difference ΔN is calculated as ΔN
= | NL-NR | (rear wheel rotational speed difference detection unit 8
1).

Next, the program proceeds to S102, in which the value of the rotational speed difference ΔN is compared with a reference value Nc to determine whether or not the left and right wheels are in a slip state (executed by the rear wheel slip determination section 82).

At S102, the rotational speed difference Δ between the left and right wheels
If N is larger than the reference value Nc (ΔN ≧ Nc), it is determined that the vehicle is in a slipping state, and the process proceeds to S103. The clutch oil pressure is set, and S105
Proceed to.

On the other hand, in S102, when the rotational speed difference ΔN between the left and right wheels is small and smaller than the reference value Nc (ΔN
<Nc) is determined to be a non-slip state and the process proceeds to S104,
The non-slip rear wheel clutch oil pressure setting unit 84 sets an oil pressure to be increased and corrected based on the vehicle speed V, the throttle opening α, the gear position e, the steering angle θ, and the acceleration g, and proceeds to S105.

Then, the above S103 or S10
When the process proceeds from S4 to S105, S103 or S
The hydraulic pressure set at 104 is duty-converted by the rear wheel duty signal conversion output unit 85 and output to the rear wheel duty solenoid valve 77 of the hydraulic control device 37.

Next, the operation of the above configuration will be described. First, the driving force of the engine 15 is transmitted from the transmission 16 to the propeller shaft 17 and the drive pinion 18.
, Is input to the rear wheel differential limiting torque generating section 19, and is input to the first sun gear 60 via the crown gear 47 and the differential case 45.

The first and second pinions 62 and 63 are connected to the second sun gear 61 and the first and second pinions 62 and 63.
The power of the second sun gear 61 is transmitted to the left rear wheel 22 via the left drive shaft 20 and the left axle shaft 21. The power of the carrier 48 is transmitted to the right rear wheel 25 via the right drive shaft 23 and the right axle shaft 24 to drive and travel.

Therefore, for example, in the straight traveling of NL = NR where the left rear wheel rotation speed and the right rear wheel rotation speed are equal, the second planetary gear type differential limiting device portion of the rear wheel differential limiting torque generating section 19 performs the second Sun gear 61 and the carrier 4
8 is rotated at the same speed in the same direction, so that the first and second
The pinions 62 and 63 are not planetary and rotate integrally.

Thus, the first and second pinions 6
When the carrier 48 and the carrier 48 are integrated with each other, no friction torque or the like is generated between the two and the carrier 48.
Of the carrier 4 with respect to the input torque Ti of the sun gear 60 of FIG.
8, the right rear wheel torque TR and the left rear wheel torque TL of the second sun gear 61 are set such that the reference torque distribution based on the gear specifications of the equal torque distribution function and the TR vs. TL are only approximately 50:50.

Next, at the time of right rear wheel slip of NR> NL where the right rear wheel rotation speed becomes larger than the left rear wheel rotation speed, the first and second pinions 6 of the rear wheel differential limiting torque generator 19 are provided.
The gears 2 and 63 rotate in a planetary manner, and perform a differential action due to gear specifications having a differential function. For this reason, at the time of turning, the rotation speed difference between the right and left rear wheels is absorbed, and the vehicle turns smoothly.

Along with the planetary rotation of the first and second pinions 62 and 63, a thrust load due to the difference in the torsion angle causes a portion of the washer 67 on one end face of the first and second pinions 62 and 63. Act on. In addition, the combined force of the separation of the gear meshing point and the tangential load acts on the first and second pinions 62 and 63 and the planetary pin 66 to cause friction torque opposite to the pinion rotation direction. A differential limiting torque based on the torque is generated.

Under this condition, the differential limiting torque acts so as to impair the rotation of the carrier 48, so that the differential limiting torque moves to the left rear wheel side, and the torque distribution is shifted leftward from the reference torque distribution. The wheels become biased. For this reason, the slip is prevented at the time of the right rear wheel slipping while traveling straight.

Further, when the left rear wheel rotational speed is larger than the right rear wheel rotational speed, that is, NL> NR, the first and second pinions 62 and 6 of the rear wheel differential limiting torque generator 19 are provided.
The planetary gears 3 similarly rotate due to the difference between the rotational speeds of the right and left rear wheels to generate friction torque.

Under this condition, the differential limiting torque acts to promote the rotation of the carrier 48 and moves to the right rear wheel, so that the torque distribution to the right rear wheel is larger than the reference torque distribution. To prevent left rear wheel slip.

Here, since the differential limiting torque by the planetary gear mechanism is proportional to the input torque, it always has the same ratio to the magnitude of the torque of the left and right rear wheels, and the differential limiting function is always constant. It is demonstrated in the ratio of.

On the other hand, in the hydraulic control device 37, the motor 70
The oil pump 71 is driven by the
2 is guided to the duty solenoid valve 77 and the clutch control valve 74. In addition, signals such as the left and right wheel rotation speeds NL and NR are used by the differential limiting torque increase correction control unit 3.
5 is processed, and the flowchart of FIG. 12 is executed to add the required differential limiting torque to the differential limiting torque generated in the composite planetary gear type differential limiting device.

Therefore, when one of the right and left wheels slips and the rotational speed difference ΔN becomes equal to or more than the reference value Nc, for example, when the vehicle is traveling on a bad road with different road surface friction coefficients, the slip rear wheel clutch hydraulic pressure setting unit 83 increases the slip speed. A high clutch oil pressure to be corrected is set, and a duty signal corresponding thereto is input to the duty solenoid valve 77, and the control oil pressure of the clutch control valve 74 is increased.

For this reason, the hydraulic chamber 56 of the hydraulic multiple disc clutch
The hydraulic piston 55 presses the drive plate 53a and the driven plate 53b, and the left drive shaft 20, which is one output side of the rear wheel differential limiting torque generating unit 19, and the other output side. Carrier 48
Generates a frictional force between them. The frictional force is added to the differential limiting torque generated in the composite planetary gear type differential limiting device as a differential limiting torque that is corrected to increase, so that an optimal differential limiting torque is obtained, and the running performance is sufficiently exhibited. Will be.

Further, when the vehicle travels on a dry road surface or the like, the rotational speed difference Δ
If N is smaller than the reference value Nc, the non-slip rear wheel clutch oil pressure setting unit 84 sets the clutch oil pressure to be increased and corrected in accordance with each running condition.

Then, based on the set clutch oil pressure, the operating oil pressure is similarly introduced into the oil pressure chamber 56 of the oil pressure multi-plate clutch, and the oil pressure piston 55
3a and the driven plate 53b are pressed to generate a frictional force between the left drive shaft 20, which is one output side of the rear wheel differential limiting torque generating unit 19, and the carrier 48, which is the other output side. The friction limiting force is added to the differential limiting torque generated by the composite planetary gear type differential limiting device as the differential limiting torque that is corrected to increase, and the optimum differential limiting torque is obtained.

The gear position e, the steering angle θ, and the
The clutch oil pressure is set by correcting with the acceleration g, and based on this value, the clutch control valve 74 is operated by the duty solenoid valve 77, and the operating oil is supplied to the hydraulic chamber 5 of the hydraulic multi-plate clutch.
From 6, drainage is performed via the clutch control valve 74 to reduce the differential limiting torque to be increased and corrected.

When the vehicle speed V is high and the throttle opening α is high or when the vehicle is starting or accelerating, the gear position e, the steering angle θ, and the acceleration g are further corrected so that the higher the value, the higher the value. By setting the clutch hydraulic pressure, the differential limiting torque to be increased and corrected is increased.

As described above, the differential limiting torque according to the accelerator work can be generated with good response at the composite planetary gear type differential limiting device, and the hydraulic multi-plate clutch can be used to generate the differential limiting torque according to the road surface condition and running condition, if necessary. A dynamic limiting torque is generated. For this reason, an optimal differential limiting torque can be obtained, and traveling performance, stability, and steering stability can be greatly improved.

Further, the required differential limiting torque can be obtained by the differential limiting torque generated by the composite planetary gear type differential limiting device and the differential limiting torque generated by the hydraulic multiple disc clutch. A large differential limiting torque can be easily secured without increasing the size of the motor.

Further, the composite planetary gear type differential limiting device has a simple structure, a small number of parts, is lightweight and compact, and therefore has excellent workability and assemblability, and is advantageous with respect to the vibration noise of the power transmission system. It can be configured while maximally sharing the conventional differential, and the hydraulic multi-plate clutch is also configured with a simple structure with a small number of parts, lightweight and compact, while maximally sharing the conventional differential. As a result, the differential limiting control device as a whole can be made light and compact with a simple structure, a small number of components, and a small number of components.

Further, since the hydraulic multi-plate clutch is pressed from one side to generate a frictional force, the number of parts is smaller than that of a clutch that generates a frictional force by pressing from both sides. It has a small, lightweight, compact and simple structure.

The hydraulic multi-plate clutch operates by being interposed between one output side and the other output side.
The differential limiting torque can be directly moved from one output side to the other output side, or from the other output side to one output side, and effective differential limiting can be performed.

Next, FIGS. 13 and 14 show a second embodiment of the present invention, and FIG. 13 shows the overall schematic configuration of a center differential device and a front wheel and rear wheel differential limiting control device of a 4WD vehicle. FIG. 14 is a functional block diagram of the differential limiting torque increase correction control unit. In the second embodiment of the present invention, a differential limiting control device is provided on the front and rear wheels of a 4WD (four-wheel drive) vehicle, and the center differential device is configured by a compound planetary gear type differential limiting device. Further, the same reference numerals are given to the same parts as in the first embodiment of the invention, and the description thereof will be omitted.

That is, the driving force of the engine 15 is
An automatic transmission (including a torque converter and the like) 91 behind the engine 15 to a transmission output shaft 91
a, and is input to the rear wheel differential limiting torque generating unit 19 via the rear drive shaft 93, the propeller shaft 17, and the drive pinion 18, while the transfer drive is transmitted from the center differential device 92. A front wheel differential limiting torque generator 98 via a gear 94, a transfer driven gear 95, and a drive pinion 97 provided on a front drive shaft 96 together with the transfer driven gear 95.
It is configured to be inputted to. Here, the automatic transmission 91, the center differential device 92,
The front wheel differential limiting torque generating section 98 and the like
It is provided within.

The driving force input to the rear wheel differential limiting torque generator 19 is applied to the left drive shaft 20 and the left axle shaft 21
To the right rear wheel 25 via the right drive shaft 23 and the right axle shaft 24.

The front wheel differential limiting torque generating section 98
Is transmitted to the left front wheel 101 via the left drive shaft 100 and to the right front wheel 1 via the right drive shaft 102.
03.

As in the first embodiment, the throttle opening sensor 28, the vehicle speed sensor 29, the steering angle sensor 31, the left rear wheel speed sensor 32, the right rear wheel speed sensor 3
3. Each of the acceleration sensors 34 is connected to the differential limiting torque increase correction control unit 104, and similarly, the TCU
Alternatively, the gear position signal e from the control unit 36 such as an ECU is also transmitted to the differential limiting torque increase correction control unit 104.
Is input to Further, a left front wheel rotation speed sensor 105 for detecting a left front wheel rotation speed NLF is provided in a housing of the left front wheel 101, and a right front wheel rotation speed sensor 106 for detecting a right front wheel rotation speed NRF is provided in a housing of the right front wheel 103. Each of them is attached and connected to the differential limiting torque increase correction control unit 104.

The differential limiting torque increase correction control unit 104
Determines the road surface state and the running state based on each input signal,
The optimum increment of the differential limiting torque generated by the differential limiting torque generator 19 is obtained and output as a signal to the hydraulic control device 37 on the rear wheel side. It is formed at a portion for obtaining an increase in the differential limiting torque and outputting a signal to the hydraulic control device 37 on the front wheel side.

The above-mentioned center differential device 92
The transmission output shaft 91a is rotatably inserted from the front of the rotatably accommodated carrier 107, while the rear drive shaft 93 is rotatably inserted from behind. Have been.

The transmission output shaft 9 on the input side
A large-diameter third sun gear 108 is formed at the rear end of 1a, and a small-diameter fourth sun gear 109 is formed at the front end of the rear drive shaft 93 that outputs power to the rear wheels. , The third sun gear 108 in the carrier 107.
And the fourth sun gear 109 are stored.

The third sun gear 108 meshes with the small-diameter third pinion 110 to form a third gear train, and the fourth sun gear 109 meshes with the large-diameter fourth pinion 111. Thus, a fourth gear train is formed.

The third pinion 110 and the fourth pinion 111 are formed integrally, and a plurality of pairs (for example, 3
The pair of pinions are rotatably supported by respective planetary pins 112 fixed to the carrier 107.

The transfer drive gear 94 is connected to the front end of the carrier 107 so that the carrier 107 outputs power to the front wheels.

That is, the driving force from the transmission output shaft 91a is transmitted to the third sun gear 108, output from the fourth sun gear 109 to the rear drive shaft 93, and from the carrier 107 to the transfer drive gear 94. , And a composite planetary gear type center differential device for outputting to the front drive shaft 96 via the transfer driven gear 95.

The composite planetary gear type center differential device comprises the third and fourth sun gears 108 and 109 and the sun gears 108 and 109.
3rd and 4th pinions 1 arranged in plurality around
The differential function is provided by appropriately setting the number of teeth of 10, 111. Further, the third and fourth sun gears 108, 1
09 and the third and fourth pinions 110 and 111 by appropriately setting the pitch circle radii, the reference torque distribution is 50:50 equal torque distribution before and after, or unequal torque biased to either front or rear. Has the function of distribution.

Further, the third and fourth sun gears 108,
109 and the third and fourth pinions 110 and 111 are, for example, helical gears, and the third gear train and the fourth gear train have different torsion angles so that the thrust load is not canceled out. With the load remaining, friction torque is applied between the pinion end faces to separate the third and fourth pinions 110 and 111 and the planetary pins 112 by meshing.
A differential limiting function is provided by setting so that a resultant force of a tangential load acts to generate a friction torque so that a differential limiting torque proportional to the input torque can be obtained.

The details of the differential function, torque distribution function, and differential limiting function of the center differential device 92 can be obtained in the same manner as in the first embodiment of the present invention. Omitted.

Next, the front wheel differential limiting torque generating section 98
Will be described. The front wheel differential limiting torque generating section 98 is configured such that the rear wheel differential limiting torque generating section 19 is disposed substantially symmetrically in a case 99, and a differential case 115 rotatably held in the case 99. The carrier 116 connected to the left drive shaft 100 therein
Is rotatably supported, and a large-diameter first case connected to the differential case 115 is accommodated in the carrier 116.
And a small-diameter second sun gear 118 connected to the right drive shaft 102 are rotatably stored.

The first sun gear 117 meshes with the small-diameter first pinion 119 to form a first gear train, and the second sun gear 118 meshes with the large-diameter second pinion 120. Thus, a second gear train is formed.

The first pinion 119 and the second pinion 120 are integrally formed, and a plurality of pairs (for example, 3
The pair of pinions are rotatably supported by respective planetary pins 121 fixed to the carrier 116.

The differential case 11
A hypoid driven gear 122 meshing with the drive pinion 97 is fixed to the outside of the gear 5.

Further, the right drive shaft 102 and the carrier 116 are rotatably connected via a plate 123 in which a drive plate on the right drive shaft 102 and a driven plate on the carrier 116 are alternately arranged.
The plate 123 is pressed by the hydraulic piston 124 from the right front wheel 103 side to generate a frictional force. The hydraulic chamber 125 that presses the hydraulic piston 124 is connected to the front-wheel-side hydraulic control device 37 via a hydraulic line 38.

That is, the front wheel differential limiting torque generating section 98 transmits the driving force from the drive pinion 97 to the first sun gear 117 via the hypoid driven gear 122 and the differential case 115, and From the sun gear 118 to the right drive shaft 1
02, while outputting to the left drive shaft 100 from the carrier 116 to form a composite planetary gear type differential limiting device. The right drive shaft 102, which is one output side, and the carrier 116, which is the other output side. And a hydraulic multi-plate clutch in which the frictional force generated according to the road surface state and the running state is varied. Then, in addition to the differential limiting torque in proportion to the input torque generated by the composite planetary gear type differential limiting device, the hydraulic multiple disc clutch increases and corrects the differential limiting torque as necessary to optimize the differential limiting torque. Is generated.

The compound planetary gear type differential limiting device includes the first and second sun gears 117 and 118 and a plurality of the first and second pinions 119 arranged around the sun gears 117 and 118. , 120 are properly set to have a differential function.

Further, the first and second sun gears 117, 117,
By appropriately setting the pitch circle radii of engagement between the first pinion 118 and the first and second pinions 119 and 120, the reference torque distribution has a function of 50:50 left and right equal torque distribution.

Furthermore, the first and second sun gear 117,
118 and the first and second pinions 119 and 120 are, for example, helical gears, and the first gear train and the second gear train have different torsion angles so that the thrust load is not canceled out. A load is left, and a friction torque is applied between the pinion end faces to separate the first and second pinions 119 and 120 and the planetary pins 121 by meshing.
A differential limiting function is provided by setting so that a resultant force of a tangential load acts to generate a friction torque so that a differential limiting torque proportional to the input torque can be obtained.

The differential function, the equal torque distribution function, and the differential limiting function can be obtained in the same manner as in the first embodiment of the present invention, and a detailed description will be omitted.
Also, the description of the rear wheel differential device will be described in the first embodiment of the invention.
The description is omitted here.

As shown in FIG. 14, the differential limiting torque increase correction control section 104 includes a front wheel side control section 104F.
And a rear wheel side control unit 104R. The front wheel side control unit 104F and the rear wheel side control unit 104R respectively provide a (front / rear wheel) rotation speed difference detection unit 81 and a (front / rear wheel) slip determination unit. 82, slip (front / rear wheel) clutch oil pressure setting unit 83, non-slip (front / rear wheel) clutch oil pressure setting unit 84
And (a front / rear wheel side) duty signal conversion output section 85.

The front wheel rotation speed difference detection unit 81 of the front wheel side control unit 104F receives the left front wheel rotation speed from the left front wheel rotation speed sensor 105 and the right front wheel rotation speed from the right front wheel rotation speed sensor 106. The rotational speed difference between the front wheels is input and calculated, and the slip determination unit 82 determines whether or not the vehicle is in a slip state based on the value of the rotational speed difference. When a high clutch oil pressure is set, and in the non-slip state, a clutch oil pressure to be increased and corrected is set by the non-slip front wheel clutch oil pressure setting section 84, and the slip front wheel clutch oil pressure setting is set by the front wheel side duty signal conversion output section 85. The hydraulic signal from the unit 83 or the non-slip front wheel clutch hydraulic pressure setting unit 84 is duty-converted to convert the hydraulic signal to the front wheel hydraulic control unit. 37 of the duty solenoid valve 7
7 is output.

Similarly, the rear wheel rotational speed difference detecting unit 81 of the rear wheel side control unit 104R receives the left rear wheel rotational speed from the left rear wheel rotational speed sensor 32 and the right rear wheel rotational speed sensor 3
The rotation speed difference is calculated by inputting the rotation speed of the right rear wheel from 3 and the rear wheel slip determination unit 82 determines whether or not the vehicle is in a slip state from the value of the rotation speed difference. A high clutch oil pressure to be increased and corrected by the clutch oil pressure setting unit 83 is set.
The non-slip rear wheel clutch oil pressure setting unit 84 sets a clutch oil pressure to be increased and corrected, and the rear wheel side duty signal conversion output unit 85 sets the slip rear wheel clutch oil pressure setting unit 83 or the non-slip rear wheel clutch oil pressure setting. The hydraulic pressure signal from the section 84 is duty-converted and output to the duty solenoid valve 77 of the hydraulic control device 37 on the rear wheel side.

Next, the operation of the above configuration will be described. First, the driving force from the engine 15 is input from the automatic transmission 91 to the third sun gear 108 of the center differential device 92 via the transmission output shaft 91a.

Then, the third and fourth pinions 110, 11
The first to fourth sun gears 109 and the carrier 107 supporting the third and fourth pinions 110 and 111 are distributed and transmitted. The power of the fourth sun gear 109 is transmitted via a rear drive shaft 93 to the rear. It is transmitted to the wheel side. The power of the carrier 107 is transferred by the transfer drive gear 9.
4, transmitted to the front wheels via the transfer driven gear 95 and the front drive shaft 96, and travels by four-wheel drive.

Therefore, for example, in the straight running of NF = NB where the front wheel side rotation speed and the rear wheel side rotation speed are equal, the fourth sun gear 10
When the carrier 9 and the carrier 107 rotate at the same speed in the same direction, the third and fourth pinions 110 and 111 do not perform planetary rotation and rotate integrally.

Thus, the third and fourth pinions 11
0, 111 and the carrier 107 are integrated with each other, so that no friction torque or the like is generated between them, and the front torque TF, TF, of the carrier 107 with respect to the input torque Ti of the third sun gear 108 The fourth sun gear 1
If the gear specifications are set to the equal torque distribution, the reference torque distribution by the gear specifications of the equal torque distribution function and the TF vs. TB are set to only about 50:50. If gear specifications are set for unequal torque distribution, TF vs. TB is set for reference torque distribution based on gear specifications of the unequal torque distribution function.

Next, at the time of turning of NF> NB or the front wheel side slip where the front wheel side rotation speed becomes larger than the rear wheel side rotation speed, the third differential of the center differential device 92 is performed.
The fourth pinions 110 and 111 perform planetary rotation, and perform a differential action due to gear specifications having a differential function. For this reason, at the time of turning, the rotation speed difference between the front and rear wheels is absorbed, and the vehicle turns smoothly.

The third and fourth pinions 110 and 111
As the planet rotates, a thrust load due to the difference in the twist angle acts on one end face of the third and fourth pinions 110 and 111. Further, the combined force of the separation of the gear mesh point and the tangential load is equal to the third and fourth pinions 11.
Acting on the portions 0, 111, and the planetary pin 112, both generate a friction torque opposite to the pinion rotation direction and a differential limiting torque based on the friction torque.

Under this condition, the differential limiting torque acts so as to impair the rotation of the carrier 107, so that the differential limiting torque moves to the rear wheel side, and the torque distribution is more deviated from the reference torque distribution than the reference torque distribution. become. For this reason, turning performance and maneuverability during turning are improved, and slipping is prevented when the front wheels slip during straight running.

Further, when the rear wheel slips on the rear wheel side where the rear wheel side rotation speed is larger than the front wheel side wheel rotation speed NB> NF, the third and fourth pinions 1 of the center differential device 92 are not rotated.
Similarly, the planetary gears 10, 111 rotate due to the difference between the rotational speeds of the front and rear wheels to generate friction torque.

Under this condition, the differential limiting torque acts to promote the rotation of the carrier 107 and moves to the front wheels, so that the torque distribution is larger on the front wheels than the reference torque distribution, and Prevent wheel slip.

Here, since the differential limiting torque by the planetary gear mechanism is proportional to the input torque, it always has the same ratio to the magnitude of the torque of the front and rear wheels, and the differential limiting function is always constant. Demonstrated in proportion.

As described above, the driving force distributed to one front wheel side of the driving force distributed by the center differential device 92 is input to the front wheel differential limiting torque generating section 98 via the front drive shaft 96 and the drive pinion 97. Then, it is input to the first sun gear 117 via the hypoid driven gear 122 and the differential case 115.

The first and second pinions 119, 12
0 to the second sun gear 118 and to the carrier 116 supporting the first and second pinions 119 and 120 for transmission. The power of the second sun gear 118 is transmitted to the right via the right drive shaft 102. The power is transmitted to the front wheel 103. Further, the power of the carrier 116 is transmitted to the left front wheel 101 via the left drive shaft 100 to drive and travel.

Therefore, for example, in the straight running of NL = NR where the left front wheel rotation speed and the right front wheel rotation speed are equal, the second sun gear 118 is provided in the composite planetary gear type differential limiting device of the front wheel differential limiting torque generating section 98. And the carrier 116 rotate at the same speed in the same direction, so that the first and the first
The second pinions 119 and 120 stop rotating around the planet and rotate integrally.

Thus, the first and second pinions 11
9 and 120 and the carrier 116 are integrated with each other, so that no friction torque or the like is generated between them, and the input torque Ti of the first sun gear 117 causes the left front wheel torque TL, The second sun gear 1
The right front wheel torque TR 18 is set such that the reference torque distribution based on the gear specifications of the equal torque distribution function and the TL vs. TR are only approximately 50/50.

Next, at the time of NL> NR left front wheel slip when the left front wheel rotation speed becomes larger than the right front wheel rotation speed, the first and second pinions 11 of the front wheel differential limiting torque generator 98 are set.
9 and 120 are planetary-rotated and act differentially by gear specifications having a differential function. For this reason, at the time of turning, the rotation speed difference between the left and right front wheels is absorbed, and the vehicle turns smoothly.

The first and second pinions 119, 120
As the planet rotates, a thrust load due to the difference in the twist angle acts on one end face of the first and second pinions 119 and 120. In addition, the combined force of the separation of the gear mesh point and the tangential load is equal to the first and second pinions 11.
9, 120 and the planetary pin 121 to generate a friction torque opposite to the pinion rotation direction and a differential limiting torque based on the friction torque.

Under this condition, the differential limiting torque acts to impair the rotation of the carrier 116, so that the differential limiting torque moves to the right front wheel side, and the torque distribution is more right-wheel biased than the reference torque distribution. become. For this reason, the slip is prevented when the left front wheel slips when traveling straight.

Further, at the time of right front wheel slip with NR> NL where the right front wheel rotation speed is larger than the left front wheel rotation speed, the first and second pinions 119,
Similarly, the planetary gears 120 rotate due to the rotational speed difference between the left and right front wheels to generate friction torque.

Under this condition, the differential limiting torque acts to promote the rotation of the carrier 116 and moves to the left front wheel side, so that the torque distribution to the left front wheel is larger than the reference torque distribution. Prevent right front wheel slip.

Here, since the differential limiting torque by the planetary gear mechanism is proportional to the input torque, it always has the same ratio to the magnitude of the torque of the left and right front wheels, and the differential limiting function is always constant. Demonstrated in proportion.

On the other hand, in the hydraulic control device 37, the motor 70
The oil pump 71 is driven by the
2 is guided to the duty solenoid valve 77 and the clutch control valve 74.

Further, signals such as the left and right wheel rotational speeds are input to the differential limiting torque increase correction control unit 104 and processed, and the differential limiting torque required on the front wheels is converted by the composite planetary gear type differential limiting device. In addition to the generated differential limiting torque.

When one of the left and right front wheels slips and the front wheel rotational speed difference ΔN becomes greater than or equal to the reference value Nc, for example, when the vehicle is traveling on a bad road with different road surface friction coefficients, the slip front wheel clutch hydraulic pressure setting unit 83 increases the slip. A high clutch oil pressure to be corrected is set, and a duty signal corresponding thereto is input to the duty solenoid valve 77, and the control oil pressure of the clutch control valve 74 is increased.

For this reason, the hydraulic chamber 12 of the hydraulic multiple disc clutch
5, the hydraulic piston 124 presses the plate 123 from one side (the right front wheel 103 side), and the right drive shaft 102 which is one output side of the front wheel differential limiting torque generating unit 98 is provided. And a carrier 116 which is the other output side. The frictional force is added to the differential limiting torque generated by the composite planetary gear type differential limiting device as a differential limiting torque that is increased and corrected to provide an optimal differential limiting torque, and the traveling performance is sufficiently exhibited. become.

When the front wheel rotational speed difference ΔN is smaller than the reference value Nc during traveling on a dry road surface, etc., the non-slip front wheel clutch hydraulic pressure setting unit 84 sets the necessary clutch hydraulic pressure to be increased and corrected according to each traveling condition. Is done.

Based on the set clutch oil pressure, the operating oil pressure is similarly introduced into the oil pressure chamber 125 of the hydraulic multi-plate clutch, and the oil pressure piston 124
Is pressed from one side (the right front wheel 103 side), and a frictional force is applied between the right drive shaft 102, which is one output side of the front wheel differential limiting torque generating section 98, and the carrier 116, which is the other output side. Is generated, and the frictional force is added to the differential limiting torque generated in the composite planetary gear type differential limiting device as a differential limiting torque that is corrected to increase to obtain an optimal differential limiting torque.

Therefore, the gear position e, the steering angle θ, the steering angle θ,
The clutch oil pressure is set by correcting with the acceleration g, and the clutch control valve 74 is operated by the duty solenoid valve 77 based on this value, and the operating oil is supplied to the hydraulic chamber 1 of the hydraulic multi-plate clutch.
From 25, drainage is performed via the clutch control valve 74 to reduce the differential limiting torque to be increased and corrected.

When the vehicle speed V is high or when the vehicle is starting or accelerating with a large throttle opening α, the gear position e, the steering angle θ, and the acceleration g are further corrected so as to increase as the value increases. By setting the clutch hydraulic pressure, the differential limiting torque to be increased and corrected is increased.

Further, the center differential device 9
The driving force distributed to the other rear wheel side of the driving force distributed to the rear wheel differential limiting torque generating unit 1 via the rear drive shaft 93, the propeller shaft 17, and the drive pinion 18
The driving force is transmitted to the left and right rear wheels by the rear wheel differential limiting torque generating unit 19 as described in the first embodiment of the present invention.

As described above, according to the second embodiment of the present invention, in addition to the center differential device in the 4WD vehicle, the differential limiting control device is also used between the front and rear left and right wheels, thereby making the embodiment of the present invention possible. In addition to the excellent effects described in 1 above, if one wheel still spins, the torque is appropriately distributed to the other 3 wheels, so that the optimal differential limiting torque can be obtained, Performance, stability and maneuvering stability can be greatly improved.

Further, the center differential device according to the second embodiment of the present invention has a simple structure, a small number of parts, is lightweight and compact, and therefore has excellent workability and assemblability, and is also capable of reducing the vibration noise of the power transmission system. It will be advantageous.

The center differential device and the differential limiting control device are both lightweight and compact, can be easily integrated, and a lightweight and compact integrated unit can be realized.

In the center differential device, the number of teeth can be set so that the reference torque distribution is distributed to the front and rear wheels at a ratio of 50:50. The vehicle travels in accordance with the traveling state or road surface conditions, prevents slippage of the vehicle, secures driving force, prevents behavior such as swinging of the vehicle, and improves running performance. In addition, it is easy to control the attitude of the vehicle with respect to the accelerator operation, and it is possible to enjoy sporty traveling with good response.

Further, since the center differential device and the differential limiting control device have a simple structure and substantially the same structure, especially when they are integrated, the service maintenance property is excellent.

Note that vehicles other than those described in the above embodiments of the invention, FF (front engine / front drive) vehicle, RR (rear engine / rear drive) vehicle, 4W
The present invention can be applied to a vehicle having a differential limiting control device between any of the front and rear wheels of the vehicle D.

In the above embodiments, the helical gear is used for the planetary gear mechanism. However, even in the case of a spur gear, the difference is determined only by the frictional force between the pinion and the bearing of the pinion shaft. It is possible to produce a dynamic limiting torque.

[0166]

As described above, according to the present invention, the structure is simple, the number of parts is small, the weight is compact, and the conventional differential is shared to the maximum while the running condition and running road surface of the vehicle are varied. An appropriate value of the differential limiting torque can be generated, and a large differential limiting torque can be effectively generated without increasing the size of the device.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an overall schematic configuration of a differential limiting control device for an FR vehicle according to a first embodiment of the present invention;

FIG. 2 is an enlarged sectional view of a differential limiting torque generating unit according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram of each part for describing a differential function according to the first embodiment of the present invention;

FIG. 4 is an operation explanatory view when the first sun gear according to the first embodiment of the present invention is fixed.

FIG. 5 is an explanatory diagram of an operation when the second sun gear according to the first embodiment of the present invention is fixed.

FIG. 6 is a schematic diagram of each part for describing a power distribution function and a differential limiting function according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram of a load generated by each gear according to the first embodiment of the present invention.

FIG. 8 is an explanatory diagram in the case where the right wheel rotation speed is higher than the left wheel rotation speed according to the first embodiment of the present invention.

FIG. 9 is an explanatory diagram when the right wheel rotation speed is smaller than the left wheel rotation speed according to the first embodiment of the present invention.

FIG. 10 is a functional block diagram of a differential limiting torque increase correction control unit according to the first embodiment of the present invention.

FIG. 11 is a configuration explanatory diagram of a hydraulic control device according to the first embodiment of the present invention.

FIG. 12 is a flowchart of a differential correction torque increase correction control according to the first embodiment of the present invention;

FIG. 13 is an explanatory diagram showing an overall schematic configuration of a center differential device and a front wheel and rear wheel differential limiting control device of a 4WD vehicle according to Embodiment 2 of the present invention.

FIG. 14 is a functional block diagram of a differential limiting torque increase correction control unit according to a second embodiment of the present invention.

FIG. 15 is an enlarged sectional view of a portion of a conventional differential device.

FIG. 16 is an enlarged sectional view of a portion of a conventional differential limiting control device.

[Explanation of symbols]

 15 Engine 16 Transmission 17 Propeller shaft 18 Drive pinion 19 Rear wheel differential limiting torque generator 20 Left drive shaft 22 Left rear wheel 23 Right drive shaft 25 Right rear wheel 28 Throttle opening degree sensor 29 Vehicle speed sensor 31 Steering angle sensor 32 Left rear Wheel speed sensor 33 Right rear wheel speed sensor 34 Acceleration sensor 35 Differential limit torque increase correction control unit 37 Hydraulic control device 38 Hydraulic line 40 Rear differential carrier 45 Differential case 47 Crown gear 48 Carrier 53 Plate 55 Hydraulic piston 56 Hydraulic pressure Chamber 60 First sun gear 61 Second sun gear 62 First pinion 63 Second pinion 65 Pinion member 66 Planetary pin 81 Rear wheel rotational speed difference detection unit 82 Rear wheel slip determination unit 83 Slip rear wheel Clutch oil pressure setting unit 84 Non-slip rear wheel clutch oil pressure setting unit 85 Rear wheel side duty signal conversion output unit

Claims (6)

[Claims] 1. A first gear train is formed by meshing a first sun gear on a driving force input side of at least one of a front wheel side and a rear wheel side with a first pinion, and forms a first gear train on a left wheel side and a right wheel side. A second sun gear on one of the output sides is meshed with a second pinion integral with the first pinion to form a second gear train;
The first and second pinions are pivotally supported by the other output-side carrier, and the difference between the thrust loads acting on the gear mesh points of the first gear train and the second gear train is determined by the first pinion. , Second
And the combined force of the separation load and the tangential load acting on the gear mesh point of the first gear train and the second gear train. And a frictional force obtained by acting on the bearing portion of the pinion 2 to generate a differential limiting torque proportional to the input torque between the left and right wheels, and the one output side and the other output side A differential limiting control device for a vehicle, characterized in that the control device is rotatably connected via a friction connecting member that variably generates a frictional force according to a road surface state and a running state. 2. A friction force variably generated by the friction coupling member according to a road surface state and a running state is increased when a rotation speed difference between left and right wheels is equal to or greater than a predetermined reference value, 2. The differential limiting control device for a vehicle according to claim 1, wherein when the vehicle speed is lower than the reference value, the vehicle speed and the engine load are increased. 3. The vehicle according to claim 1, wherein the frictional connection member is formed by a hydraulic multi-plate clutch that operates with a pressing force that is variably controlled according to a road surface state and a running state. Differential limit control device. 4. The differential limiting control device for a vehicle according to claim 3, wherein the pressing force is applied from one side of the hydraulic multiple disc clutch. 5. The apparatus according to claim 1, wherein the driving force is supplied from a center differential device.
4. The vehicle differential limiting control device according to any one of items 3. 6. The center differential device forms a third gear train by meshing a third sun gear on an input side with a third pinion, and forms a third gear train on one of an output side of a front wheel side and a rear wheel side. A fourth sun gear meshes with a fourth pinion integral with the third pinion to form a fourth gear train,
The third and fourth pinions are pivotally supported by the other output-side carrier, and the difference between the thrust load acting on the gear mesh point of the third gear train and the fourth gear train is determined by the third gear train. , 4th
And the combined force of the separation load and the tangential load acting on the gear mesh point of the third gear train and the fourth gear train, and the frictional force obtained by acting on one end face of the pinion. 6. The vehicle differential according to claim 5, wherein a differential limiting torque proportional to the input torque is generated between the front and rear wheels by a frictional force obtained by acting on a shaft support portion of the pinion. Limit control device.