Jtekt Corporation

Toyoda Koki Kabushiki Kaisha

Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Aisin Ai Co., Ltd.

Akihiro Ohno

Tsuyoshi Murakami

Yutaka Mori

Kunihiko Eto

Tomoaki Kato

Ryohei Shigeta

Ryouhei Shigeta

Takeshige Miyazaki

Hiroshi Takuno

Toshifumi Sakai

Go Nagayama

Naoyuki Sakai

Yoshiyuki Aoyama

Masaki Mita

Yasushi Yamada

Kazutaka Kobayashi

Tadashi Yoshioka

Shunzo Tanaka

Masahiro Horaguchi

Seitoku Kubo

Hiroaki Kato

Minekazu Momiyama

Kazumasa Kodama

Takashi Hosokawa

Yukio Okamura

Shinji Takeuchi

Tomohiro Nozu

Akira Kodama

Hiroshi Kushino

Shigeo Tanooka

Tadanobu Kumagai

Shigeo Iwashita

Hiroyuki Ando

Yoshiharu Amano

Takashi Shirai

A drive state control apparatus is applied to a vehicle which has not only a transfer including a multi-disc clutch mechanism but also a changeover mechanism interposed in an axle and which can be switched between 2WD and 4WD. When a 2WD-to-4WD changeover condition is satisfied, the multi-disc clutch is immediately switched from a 'decoupled state' to a 'coupled state.' Meanwhile, a connecting operation of the changeover mechanism is started upon establishment of a state in which left and right rear wheels have no acceleration slippage, and a state in which rotational speeds of first and second axles on opposite sides of the changeover mechanism are approximately equal to each other. In addition, in the case where the left and right rear wheels have acceleration slippage after the 2WD-to-4WD changeover condition has been satisfied, an E/G output reduction control is executed. Thus, the connecting operation can be performed smoothly.

Drive state control apparatus for vehicle

A four-wheel drive vehicle includes: a driving force transmission system which transmits torque of a drive source to front wheels and rear wheels via gear mechanisms; a clutch provided in the driving force transmission system and capable of controlling an amount of the torque transmitted to the rear wheels; and a pressing mechanism which presses the clutch by transforming a part of the torque transmitted to the rear wheels into axial thrust. In the driving force transmission system, gear ratios of the gear mechanisms are set such that a direction of a differential rotation between a drive shaft connected to an input side of the clutch and a drive shaft connected to an output side of the clutch is not reversed even when a steered angle of the front wheels changes to a maximum value while the four-wheel drive vehicle is traveling forwards.

Four-wheel drive vehicle

A four-wheel-drive vehicle includes: a drive source which generates torque forming a driving force of the vehicle; a driving force transmission system which transmits the torque of the drive source to main driven wheels and auxiliary driven wheels; and a dog clutch provided in the driving force transmission system and capable of transmitting the torque to an auxiliary driven wheel side by engagement of a recess portion and a protruding portion. The vehicle further includes: a determination unit which determines whether a friction coefficient of a road surface is lower than a predetermined value based on an index value relating to the friction coefficient of the road surface; and a control unit which generates a control signal which causes engagement of the dog clutch before the vehicle starts when the determination unit determines that the friction coefficient of the road surface is lower than the predetermined value.

Four-wheel-drive vehicle and control unit

An on-demand-type drive state control apparatus for a vehicle is provided. In the case where acceleration slippage occurs at drive wheels (rear wheels) of a vehicle when a drive system is in a two-wheel drive state, the drive system is switched from the two-wheel drive state to a four-wheel drive state. That is, the maximum transmittable torque of a multi-disc clutch mechanism increases from '0' to a predetermined value. In the four-wheel drive state, the maximum transmittable torque decreases stepwise from the present value by a predetermined value every time the vehicle travels over a predetermined distance in a state in which none of the wheels cause acceleration slippages. That is, the clutch drive current supplied to the multi-disc clutch mechanism decreases gradually (stepwise or in a plurality of steps), and the drive torque distributed to the front wheels (rear wheels) decreases (increases) gradually.

When determining that a vehicle is not skidding, the ECU carries out tight corner control if vehicle speed is smaller than the upper limit value of the vehicle speed range corresponding to the starting state of the vehicle and the steering wheel turning angle of a steering wheel is greater than or equal to the minimum value of the steering wheel turning angle at which the tight corner braking phenomenon may occur. When determining that the vehicle is skidding, the ECU inhibits the tight corner control even if the vehicle speed is smaller than the upper limit value and the steering wheel turning angle is greater than or equal to the minimum value of the steering wheel turning angle at which the tight corner braking phenomenon may occur.

Drive force transmission apparatus, control method of drive force transmission apparatus, and limited slip differential

An IG-off-timer measures the time t_off from when an engine is stopped, or an ignition is turned off. An ECU sequentially memorizes an estimated temperature of each of heat generating portions as a memorized temperature. Immediately after the engine is re-started, the ECU sets an initial value of the estimated temperature of each heat generating portion in such a manner that the initial value reflects a temperature drop of the heat generating portion in the deactivation period of the engine. The temperature of the heat generating portion is thus accurately estimated even after re-starting of the engine. The heat generating portions are thus appropriately protected.

Drive force distribution device and method for distributing drive force

An ECU estimates the temperatures of the heat generating portions provided in a drive force transmission system, or a transaxle, a rear differential, and a torque coupling, in correspondence with not only the rotational speed (the differential rotational speed) of each heat generating portion and the torque transmission rate of the torque coupling but also the outside temperature detected by an outside temperature sensor. If the estimated temperature of any of the heat generating portions exceeds a respective predetermined temperature, the ECU controls operation of the torque coupling to suppress overheating of the heat generating portion. That is, the temperature of each heat generating portion is accurately detected through a simplified structure and overheating of the heat generating portion is effectively suppressed.

A control device is provided for electrically controlling a drive power transmission device arranged on a driving power transmission path of a front-and rear wheel drive vehicle thereby to switch the drive mode of the vehicle selectively to either of a two-wheel drive mode and a four-wheel drive mode. The control device inhibits the drive mode from being switched to that commanded to be switched to when the vehicle is traveling at a slower speed than a predetermined speed and when the rotational speed difference between front and rear wheels is larger than a predetermined value. Further, the control device gradually decreases a present torque which the driving power transmission device is transmitting before the switching of the drive mode, to a target torque which the drive power transmission device is to transmit after the switching of the drive mode, when the difference between the present and target torques is more than another predetermined valve at the time of the switching of the drive mode. Thus, the driving power transmission path can be prevented from generating the drive torque beyond a tolerable valve as well as making a noise due to the instantaneous switching of the drive mode during the traveling of the vehicle, and the vehicle can be prevented from abruptly changing its motion by the cause of the instantaneous drive mode switching.

Control device for front-and-rear wheel drive vehicle

A vehicle drive deviceis composed of an electric motor, a differential gearfor distributing and transmitting the drive power from the electric motorto right and left drive wheels, and a clutchfor making intermittent the coupling capable of transmitting the drive power between the differential gearside and the electric motorside. The clutchis of the type having a self-locking function and is arranged coaxially of the differential gearat one side of the differential gear

Vehicle drive device, and front-and-rear wheel-driven vehicle formed of the device

Front and rear wheels Tf, Tr of a motor vehicle driven by an engineare connected through a differential control devicewhich is capable of varying the torque to transmit. When the turning radius of a predetermined one wheel or the motor vehicle is equal to or smaller than a predetermined turning radius, the transmission torque of the differential control device is decreased by a control device to prevent the tight-corner braking phenomenon from occurring. When the motor vehicle is stopped momentarily with the transmission torque being lowered, the control device maintains the transmission torque as it is, and the vehicle is then restarted with the transmission torque being lowered. Thus, when the motor vehicle which was stopped momentarily with a large steering angle is then restarted, the tight-corner braking phenomenon can be prevented from occurring from the beginning of the restarting.

Drive power transmission equipment

In a steering system, a transmission ratio Rwhich is determined in dependence on the vehicle speed by reference to a transmission ratio decision map is multiplied with a first transmission ratio alteration gain gwhich is determined in dependence on the distribution of a traveling drive torque from an engineto front wheelsand rear wheels, thereby to alter the ratio Rof steering torque distribution from a steering handleto the front wheels, whereby the variation of the steering feeling due to an increase or decrease in the distribution of the traveling drive torque to the front wheelscan be suppressed. Further, the transmission ratio Ris multiplied with a second transmission ratio alteration gain gwhich is determined in dependence on the gradient of the road surface by reference to a second transmission ratio alteration map, thereby to alter the transmission ratio R, whereby the variation of the steering feeling due to the variation of the gradient can also be suppressed.

Steering system for vehicle

A drive system control method and a drive power transmission control system for a four-wheel drive vehicle are provided for enabling the vehicle to operate selectively in an ordinary mode and an anti-vibration mode. In the ordinary mode, the connection force of a coupling device which is provided between front and rear wheel torque transmission axles is kept relatively high, and the front and rear wheel torque transmission axles are brought to connect prime drive wheels with secondary drive wheels, so that four-wheel drive traveling of the vehicle can be realized. The operation mode of the vehicle is switched from the ordinary mode to the anti-vibration mode where the secondary drive wheels slip when the vehicle begins to start in the ordinary mode. In the anti-vibration mode, the connection force of the coupling device is relatively weakened to substantially separate the front and rear wheel torque transmission axles from each other. Thus, the resilient force produced by the torsion of the front and rear wheel torque transmission axles which is caused by the slip of the prime drive wheels or the secondary drive wheels is released between the front and rear wheel torque transmission axles, so that the vibration which would otherwise be generated when the vehicle performs the four-wheel drive starting can be suppressed compared with that in the prior art.

Drive system control method and drive power transmission control system for vehicle

An ECU, which functions as a driving force distribution control apparatus for a four-wheel drive vehicle, includes a CPU. The CPU controls a coupling for changing torque distribution of front and rear wheels. The CPU determines either of first and second torque distribution modes based on detection signals of a throttle opening sensor and steering angle sensor, which are operating parameters. In the second torque distribution mode, torque is distributed to the front and rear wheels more equally than in the first torque distribution mode. The CPU sets a duration for the second torque distribution mode when the second torque distribution mode is selected. Until the duration elapses, regardless of the operating parameters, the CPU continues the control of the coupling in the second torque distribution mode.

Driving force distribution control device and driving force distribution method for four-wheel drive vehicle

A drive system for an automotive vehicle of the front-and-rear wheel drive type, comprising a primary drive mechanism for drive of a set of front road wheels and an ancillary drive mechanism for drive of a set of rear roar wheels, wherein the front road wheels are driven by operation of the primary drive mechanism at a two-wheel drive mode and wherein the front and rear road wheels are driven by operation of both the primary and ancillary drive mechanisms at a four-wheel drive mode. In the drive system, a drive power applied to the primary road wheels is restricted to a predetermined value when the vehicle is driven by the primary and ancillary drive mechanisms at the front-and-rear wheel drive mode.

Drive system for automotive vehicle of front-and-rear wheel drive type

A power distribution control apparatus determines a command value that corresponds to the driving state of a four-wheel drive vehicle. The vehicle includes a pair of front wheels and a pair of rear wheels, and a coupling device that changes the power distribution to the front wheels and the rear wheels. The control apparatus detects the differential rotation speed between the average rotation speed of the front wheels and the average rotation speed of the rear wheels. The control apparatus estimates the exothermic energy generated in the coupling device based on the product of the differential rotation speed and the command value. The control apparatus determines an optimum drive mode for the four-wheel drive vehicle based on the estimated exothermic energy and for selecting map data corresponding to the determined drive mode. The control apparatus determines the command value that corresponds to the driving state by using the map data.

Growing community of inventors

Okazaki, Japan

Akihiro Ohno