JP2001063397A - Turning support device for vehicles - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent a vehicle equipped with an automatic transmission from disturbing vehicle behavior due to slipping of a drive wheel having increased driving force due to a downshift during turning acceleration. A vehicle provided with an automatic transmission is provided with a driving force distribution device, and distributes a driving force from a driving wheel inside a turn to a driving wheel outside a turn when turning. As a result, even if the automatic transmission shifts down during turning acceleration and the driving force transmitted from the engine to the driving wheels increases, the driving force of the driving wheels inside the turning, which is likely to slip due to the small friction circle, is reduced in advance. Therefore, it is possible to prevent a situation in which the driving wheels on the inside of the turn slip due to the downshift and the vehicle behavior is disturbed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises an automatic transmission for establishing a gear position selected based on a throttle opening and a vehicle speed, and transmitting the driving force of an engine to left and right driving wheels via the gear position. The present invention relates to a turning support device for a vehicle.

[0002]

2. Description of the Related Art In a vehicle equipped with a manual transmission, the ratio of distributing the driving force of the engine to the left and right driving wheels is made variable, so that the driving force distributed to the outer turning wheels is increased and the driving force distributed to the inner turning wheels is reduced. A technique for generating a yaw moment in the turning direction to enhance the turning performance is known.

[0003]

The turning vehicle leans outward in the turning direction due to centrifugal force, so that the contact load of the inner turning wheel decreases and the contact load of the outer turning wheel increases. Since the diameter of the friction circle, which is an indicator of the magnitude of the grip force of the wheel, changes in proportion to the ground contact load of the wheel, the diameter of the friction circle of the turning inner wheel decreases, and conversely, the diameter of the friction circle of the turning outer wheel increases. To increase. The frictional force acting between the wheels and the road surface is represented by the vector sum of the driving force along the traveling direction of the vehicle and the lateral force orthogonal to the traveling direction of the vehicle, and the vector sum of the above-mentioned vector whose base end is located at the center of the friction circle. If the tip protrudes outside the friction circle, a slip occurs between the wheel and the road surface.

[0004] Figure 7 shows a state in which the front-wheel drive vehicle having an automatic transmission is turning left, with a change in the vertical load caused by the centrifugal force, the friction circle FC _L of the left front wheel W _FL as a turning-inner diameter smaller than the diameter of the friction circle FC _R of the right front wheel W _FR is the outer turning wheel. Figure (vector sum of the driving force D _L and lateral force S _L) frictional force F _L between the left front wheel W _FL and the road surface is a turning inner in the state of 7 (A) is in the range of the corresponding friction circle FC _L and since a turning outer front right wheel W _FR and frictional force F _R between the road surface (the vector sum of the driving force D _R and lateral force S _R) are also within the scope of the corresponding friction circle FC _R, left and right front wheels W _{Both FL} and W _FR grip the road surface without slipping.
In a conventional vehicle without a driving force distribution device, the driving force of the engine is evenly distributed to the left and right front wheels W _FL and W _FR via a differential gear, so that the frictional force F between the left front wheel W _FL and the road surface is increased. Driving force D, which is the vehicle traveling direction component of _L
And _L, is equal to the driving force D _R is a vehicle traveling direction component of frictional force F _R between the right front wheel W _FR and the road surface.

When the accelerator pedal is depressed to accelerate the vehicle, the automatic transmission is shifted down to a lower gear (kick down), so that the driving force D _L transmitted from the engine to the left and right front wheels W _FL , W _FR . D _L D _R is increased by the same amount ', D _R' becomes. At this time, for example, if the vehicle is in a left turning state, FIG.
(B), the frictional force F _L of the left front wheel W _FL is smaller in diameter friction circle FC _L '(driving force D _L' and the vector sum of the lateral force S _L) for protrudes the friction circle FC _L As a result, the grip of the left front wheel W _FL is lost, and the vehicle tends to understeer.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and prevents a vehicle equipped with an automatic transmission from disturbing vehicle behavior due to slipping of a drive wheel having increased driving force due to a downshift during turning acceleration. The purpose is to do.

[0007]

According to the first aspect of the present invention, a gear position selected based on a throttle opening and a vehicle speed is established. In a vehicle equipped with an automatic transmission for transmitting the driving force of the engine to the left and right driving wheels, a driving force distribution device for distributing the driving force between the left and right driving wheels is provided. A turning support device for a vehicle, characterized in that a driving force is distributed from a driving wheel inside a turn to a driving wheel outside a turn in accordance with the following.

According to the above configuration, when a vehicle equipped with an automatic transmission accelerates during turning,
Even if a downshift occurs and the driving force transmitted from the engine to the driving wheels increases, the driving force distribution device controls the driving force distributed between the left and right driving wheels according to the turning state of the vehicle,
By reducing the driving force transmitted to the turning inner wheel that has become easier to slip due to the decrease in the ground load due to turning,
The slip of the turning inner wheel can be prevented to stabilize the behavior of the vehicle.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

1 to 6 show an embodiment of the present invention. FIG. 1 is a diagram showing a structure of a driving force distribution device, FIG. 2 is a block diagram showing a circuit configuration of an electronic control unit, and FIG. FIG. 4 is a diagram illustrating the operation of the driving force distribution device during a right turn, FIG. 4 is a diagram illustrating the operation of the driving force distribution device during a left turn, FIG. 5 is a diagram illustrating a table that controls the speed change of the automatic transmission, and FIG. FIG. 3 is a diagram illustrating friction circles of left and right front wheels of the vehicle according to the embodiment.

As shown in FIG. 1, an automatic transmission M is mounted on the right end of an engine E mounted horizontally on the front of the vehicle body of a front engine / front drive vehicle.
Are connected, and a driving force distribution device T is arranged at the rear of the engine E and the automatic transmission M. The left drive shaft A _L and the right drive shaft A _R extending right and left from the left end and the right end of the driving force distribution device T have a left front wheel W _FL and a right front wheel W _FR , respectively.
Is connected.

The driving force distribution device T includes a differential device D to which driving force is transmitted from an external gear 3 meshing with an input gear 2 provided on an input shaft 1 extending from the automatic transmission M. The differential device D is composed of a double pinion type planetary gear mechanism, and includes a ring gear 4 formed integrally with the external gear 3, a sun gear 5 disposed coaxially inside the ring gear 4, and a ring gear 4. The outer planetary gear 6 meshes with the planetary carrier 8 that supports the inner planetary gear 7 meshing with the sun gear 5 while meshing with each other. Differential device D, together with the ring gear 4 functions as an input element, a sun gear 5 which functions as one output element is connected to the left front wheel W _FL via the left output shaft 9 _L, also serves as the other output element planetary carrier 8 which is connected to the right front wheel W _FR via the right output shaft 9 _R.

The carrier member 11 rotatably supported on the outer periphery of the left output shaft 9 _L is provided with four pinion shafts 12 arranged at 90 ° intervals in the circumferential direction. The triple pinion member 16 integrally formed with the two pinions 14 and the third pinion 15 is attached to each of the pinion shafts 12.
Are rotatably supported.

A first sun gear 17 rotatably supported on the outer periphery of the left output shaft 9 _L and meshing with the first pinion 13.
Are connected to the planetary carrier 8 of the differential D.
The second sun gear 18 fixed to the outer periphery of the left output shaft 9 _L
Meshes with the second pinion 14. Further, the left output shaft 9
_A third sun gear 19 rotatably supported on the outer periphery of _L meshes with the third pinion 15.

The numbers of teeth of the first pinion 13, the second pinion 14, the third pinion 15, the first sun gear 17, the second sun gear 18, and the third sun gear 19 in the embodiment are as follows.

Number of teeth of first pinion 13 Z ₂ = 17 Number of teeth of second pinion 14 Z ₄ = 17 Number of teeth of third pinion 15 Z ₆ = 34 Number of teeth of first sun gear 17 Z ₁ = 32 Second sun gear 18 number of teeth Z ₃ = 28 number of teeth Z ₅ = 32 third sun gear 19 of the third sun gear 19 of is capable of binding to the casing 20 via a left hydraulic clutch C _L, carrier by engagement of the left hydraulic clutch C _L The rotation speed of the member 11 is increased. The carrier member 11 can be coupled to the casing 20 via a right hydraulic clutch C _R, the rotational speed of the carrier member 11 is reduced by engagement of the right hydraulic clutch C _R. The right hydraulic clutch C _R and the left hydraulic clutch C
_L is an electronic control unit U including a microcomputer
Is controlled by

As shown in FIG. 2, the electronic control unit U, the engine rotational speed detecting means S ₁ for detecting an engine speed Ne, means S ₂ out intake negative pressure for detecting an intake negative pressure Pb of the engine E When a gear position detecting means S ₃ for detecting a gear position P of the automatic transmission M, the driving wheel speed Vd and the driven wheel speed detecting means S ₄ for detecting the (front wheel speed), the driven wheel speed Vf (rear wheel speed)
A driven wheel speed detecting means S ₅ for detecting a signal from the lateral acceleration detecting means S ₆ Metropolitan for detecting a lateral acceleration Yg of the vehicle. The electronic control unit U is provided with each of the detection means S ₁ to S ₁ .
The signal from the S ₆ to arithmetic processing based on a predetermined program, the left hydraulic clutch C _L and the right hydraulic clutch C _R
Control.

Next, the operation of the embodiment of the present invention having the above configuration will be described.

The speed change table of the automatic transmission M shown in FIG. 5 has a vehicle speed V and a throttle opening θ.
_TH is used as a parameter, and hysteresis is set between a shift-up table (see FIG. 5A) and a shift-down table (see FIG. 5B). When the vehicle speed V and the throttle opening θ _TH cross the three shift lines set in the table of FIG. 5A from left to right or from above to below, the automatic transmission M shifts from first gear to second gear, 2nd to 3rd speed,
Alternatively, the gear is shifted up from third gear to fourth gear. When the vehicle speed V and the throttle opening θ _TH cross the three shift lines set in the table of FIG. 5B from right to left or from bottom to top, the automatic transmission M shifts from fourth gear to third gear. 3rd to 2nd or 2nd
The gear is downshifted from first gear to first gear.

Therefore, when the accelerator pedal is suddenly depressed to accelerate the vehicle, the throttle opening θ _TH increases and crosses the speed change line of the table shown in FIG. 5B from the lower side to the upper side, and the automatic transmission M shifts. Be downed.

Next, control of the driving force distribution device T will be described.

In FIG. 2, the engine speed detecting means S
By applying the intake negative pressure Pb detected by the engine speed Ne and the intake negative pressure detection means S ₂ detected by ₁ to an engine torque table, searching engine torque Te. Also based on the gear position P of the automatic transmission M detected by the gear position detecting means S _3, as well as search for speed reduction ratio It to the gear position, the driving wheel speed detecting means S ₄ is detected by the driving wheel speed V
The inertia torque Ta of the power transmission system is calculated from the average value of d. Then, based on the engine torque Te, the reduction ratio It, and the inertia torque Ta of the power transmission system, the drive torque Td of the front wheels W _FL , W _{FR as} the drive wheels is calculated by Td = Te * It−Ta.

Next, from the average differential value of the driven wheel speed Vf detected by the follower wheel speed detecting means S _5, and calculates the sum Rr of rolling resistance and air resistance of the vehicle. And the driving torque Td, the sum Rr of the rolling resistance and the air resistance,
Based on the vehicle weight and the tire effective diameter, the longitudinal acceleration Xg of the vehicle is calculated by Xg = Td / (vehicle weight * tire effective diameter) -Rr.

Next, a longitudinal acceleration Xg of the vehicle and a lateral acceleration Yg of the vehicle detected by the lateral acceleration detecting means S ₆ is applied to the right and left distribution torque table, the turning outer wheel from the inner wheel by the driving force distribution device T Drive torque distribution amount T to be distributed
Search for r. As is clear from the left and right distribution torque table, the drive torque distribution amount Tr is set to increase as the longitudinal acceleration Xg of the vehicle increases, and to increase as the lateral acceleration Yg of the vehicle increases. And by applying the driving torque distribution amount Tr hydraulic clutch drive amount table, the left and right hydraulic clutch C _L, searches the driving amount of Ar C _R.

Next, the operation of the driving force distribution device T will be described.

In response to a command from the electronic control unit U, the right hydraulic clutch C _R and the left hydraulic clutch _CL are both disengaged when the vehicle is traveling straight. As a result, the restraint of the carrier member 11 and the third sun gear 19 is released, and the left drive shaft 9 _L , the right drive shaft 9 _R , the planetary carrier 8 of the differential device D and the carrier member 11 all rotate integrally. At this time, the torque of the engine E is evenly transmitted from the differential device D to the left and right front wheels W _FL and W _FR , as indicated by hatched arrows in FIG.

Now, when the vehicle turns right while accelerating,
The command from the electronic control unit U as shown in FIG.
By right hydraulic clutch C_RAre engaged and the carrier member 11
Is coupled to the casing 20 and stopped. At this time, left
Front wheel W_FLLeft output shaft 9 integrated with _LAnd the right front wheel W_FRWith one
Right output shaft 9_R(That is, the planetary carrier of the differential D)
8) means the second sun gear 18, the second pinion 14, the first
Connected via a pinion 13 and a first sun gear 17
The front left wheel W_FLRotation speed N_LIs the right front wheel W_FRTimes
Number of turns N_RIs increased by the following equation.

N _L / N _R = (Z ₄ / Z ₃ ) × (Z ₁ / Z ₂ ) = 1.143 (3) As described above, the rotation speed N _L of the left front wheel W _FL is increased to the right front wheel. W
_{When the} speed is increased with respect to the rotational speed N _{R of the FR} , as shown by the hatched arrow in FIG. 3, a part of the torque of the right front wheel W _FR which is the turning inner wheel is partially converted to the left front wheel W which is the turning outer wheel. Can be transmitted to _FL .

The carrier member 11 is connected to the right hydraulic clutch C
Instead of stopping by _R, if reducing the rotational speed of the carrier member 11 by appropriately adjusting the engagement force of the right hydraulic clutch C _R, the right front wheel W _FR and rotation speed N _L of the left front wheel W _FL in accordance with the deceleration can Hayashi increased relative to the rotational speed N _R, to transmit any torque from the right front wheel W _FR as a turning-inner to the left front wheel W _FL is the outer turning wheel.

On the other hand, when the vehicle makes a left turn while accelerating
The command from the electronic control unit U as shown in FIG.
By left hydraulic clutch C_LAre engaged, and the third pinion 15
Is connected to the casing 20 via the third sun gear 19.
You. As a result, the left output shaft 9_LCarrier for rotation speed of
The rotation speed of the member 11 is increased, and the right front wheel W_FRRotation speed N _R
Is the front left wheel W_FLRotation speed N_LTo the following equation
It is.

N _R / N _L = {1- (Z ₅ / Z ₆ ) × (Z ₂ / Z ₁ )} {1- (Z ₅ / Z ₆ ) × (Z ₄ / Z ₃ )} = 1 .167 (4) As described above, the rotation speed N _R of the right front wheel W _FR is changed to the left front wheel W
_{When the} speed is increased with respect to the rotation speed _{NL of the FL} , as shown by the hatched arrow in FIG. 4, a part of the torque of the left front wheel W _FL which is the turning inner wheel is partially shifted to the right front wheel W which is the turning outer wheel. Can be communicated to _FR . In this case, when accelerating the rotation speed of the carrier member 11 by appropriately adjusting the engagement force of the left hydraulic clutch C _L, left front wheel W _FL rotation speed N _R of the right front wheel W _FR in accordance with the speed increasing The rotation speed is increased with respect to the rotation speed N _L , and an arbitrary torque can be transmitted from the left front wheel W _{FL as the} turning inner wheel to the right front wheel W _FR as the turning outer wheel.

Thus, at the time of turning acceleration of the vehicle, it is possible to improve turning performance by transmitting a larger torque to the outer turning wheel than to the inner turning wheel. In addition, it is possible to reduce the torque transmitted to the turning outer wheel during high-speed running as compared with during low-speed running, or to improve the running stability performance by transmitting torque from the turning outer wheel to the turning inner wheel.

As is clear from the comparison of the equations (3) and (4), the first pinion 13, the second pinion 14, the third pinion 15, the first sun gear 17, and the second sun gear 18
And the number of teeth of by a set as described above third sun gear 19, the speed increasing ratio from the right front wheel W _FR to the left front wheel W _FL (about 1.143), increasing from the left front wheel W _FL to the right front wheel W _FR The speed factor (about 1.167) can be made substantially equal.

[0034] FIG. 6 (A) is shown a state in which the vehicle turns left while accelerating the present embodiment, the left front wheel W _FL as a turning-inner of the function of the driving force distribution device T described above small driving force D _L is distributed, the right front wheel W is the outer turning wheel
Driving force D _R are allocated larger the _FR. When downshifting of the automatic transmission M with the acceleration from this state is performed, the driving force D _R of the driving force D _L and the right front wheel W _FR of the left front wheel W _FL increases in the same ratio, respectively Figure 6 (B) And D _L ′ and D _R ′.

As is apparent from a comparison between FIG. 7 corresponding to the conventional vehicle without the driving force distribution device T and FIG. 6 corresponding to the vehicle of the present embodiment including the driving force distribution device T, since the driving force D _L of the left front wheel W _FL in this embodiment is a turning inner by the drive force distribution device T shown in FIG. 6 is reduced in advance, the driving force of the left front wheel W _FL by downshifting from D _L Even if it increases to D _L ', its driving force D _L '
And lateral force S _L frictional force F _L is the vector sum of hardly protrude the friction circle FC _L, the vehicle can be prevented a situation to be understeer lost grip of the left front wheel W _FL.

By combining the vehicle provided with the automatic transmission M with the driving force distribution device T, even if a downshift occurs during the turning acceleration of the vehicle, the turning inner wheel is prevented from slipping and the vehicle behavior is reduced. Can be held stably.

It is to be noted that the driving force distribution device T uses the turning outer wheel.
A certain front right wheel W_FRDriving force distributed to_RAlso increases,
Right front wheel W which is originally a turning outer wheel_FRFriction circle FC_RThe diameter of
The driving force is D_RTo D
_R′, The right front wheel W _FRFrictional force F_RIs the friction circle F
C_RThere is no danger of protruding.

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof.

For example, in the embodiment, the driving force distribution device T distributes the driving force between the left and right front wheels W _FL and W _FR , but distributes the driving force between the left and right rear wheels W _RL and W _RR. It may be.

Although the lateral acceleration Yg is used as an index indicating the turning state of the vehicle in the embodiment, a steering angle or a yaw rate can be employed instead of the lateral acceleration Yg.

[0041]

As described above, according to the first aspect of the present invention, when a vehicle equipped with an automatic transmission accelerates during turning, a downshift occurs and is transmitted from the engine to the drive wheels. Even if the driving force increases, the driving force distribution device controls the driving force distributed between the left and right driving wheels according to the turning state of the vehicle, and the turning inner wheels that are more likely to slip due to the decrease in the ground contact load due to turning By reducing the transmitted driving force, slip of the turning inner wheel can be prevented and vehicle behavior can be stabilized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a driving force distribution device.

FIG. 2 is a block diagram showing a circuit configuration of an electronic control unit.

FIG. 3 is a diagram showing the operation of the driving force distribution device during a right turn.

FIG. 4 is a diagram showing the operation of the driving force distribution device during a left turn.

FIG. 5 is a diagram showing a table for controlling a shift of an automatic transmission.

FIG. 6 is a diagram showing friction circles of left and right front wheels of the vehicle according to the embodiment.

FIG. 7 is a diagram showing friction circles of left and right front wheels of a conventional vehicle.

[Explanation of symbols]

E Engine M Automatic transmission Ne Engine speed T Driving force distribution device V Vehicle W _FL Front wheel (Drive wheel) W _FR Front wheel (Drive wheel) Yg Lateral acceleration (Vehicle turning state) θ _TH Throttle opening

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoyuki Niimura 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Inventor Masakatsu Hori 1-4-1 Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. (72) Inventor Shinji Okuma 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Akihiro Iwasaki 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside the Honda R & D Co., Ltd. (72) Kazuhiro Wada 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside the Honda R & D Co., Ltd. (72) Yasunori Arai 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (reference) 3D036 GA42 GG20 GG24 GG35 GG41 GH23 GJ01

Claims (1)

[Claims] 1. A gear position selected based on a throttle opening (θ _TH ) and a vehicle speed (V) is established, and a driving force of an engine (E) is transmitted through the gear position through left and right drive wheels (W _FL , W _FL) . W _FR ) includes a driving force distribution device (T) that distributes driving force between left and right driving wheels (W _FL , W _FR ). (T) is at least in accordance with the turning state of the vehicle (Yg) turning inward of the drive wheels (W _FL, W _FR) from the outside of the turn of the drive wheels (W _FL, W
A turning support device for a vehicle, wherein the driving force is distributed to _FR ).