Vehicle four-wheel drive apparatus

Patent metadata

Field	Value
Publication number	US-2016101689-A1
Application number	US-201514877417-A
Country	US
Kind code	A1
Filing date	Oct 7, 2015
Priority date	Oct 8, 2014
Publication date	Apr 14, 2016
Grant date	—

Abstract

By driving a first electromagnetic solenoid and a second electromagnetic solenoid, if first cams of a first thrust force amplification mechanism and a second thrust force amplification mechanism are connected to non-rotary members, since second cams are rotated at rotating speeds that are proportional to a vehicle speed V, the relative rotations between the first cam and the second cam increase. Therefore, the first thrust force amplification mechanism and the second thrust force amplification mechanism can be actuated quickly, to thereby switch connection/disconnection states of the first connection/disconnection mechanism and the second connection/disconnection mechanism quickly.

First claim

1 . A vehicle four-wheel drive apparatus comprising:
a transfer for transmitting a portion of driving force that is output from a drive source to auxiliary drive wheels; a propeller shaft that is interposed between the transfer and the auxiliary drive wheels for transmitting a power from the transfer to the auxiliary drive wheels; a first connection/disconnection mechanism that is provided in the transfer for selectively connecting or disconnecting the power transmitted to the propeller shaft via the transfer; a second connection/disconnection mechanism that is provided between a downstream side of the propeller shaft and the auxiliary drive wheels for selectively connecting or disconnecting the power between the propeller shaft and the auxiliary drive wheels, a first thrust force amplification mechanism for switching a connection/disconnection state of the first connection/disconnection mechanism; a first control clutch; a first actuator; a second thrust force amplification mechanism for switching connection/disconnection state of the second connection/disconnection mechanism; a second control clutch; and a second actuator, wherein each of the first connection/disconnection mechanism and the second connection/disconnection mechanism has a switching member, the switching member is configured to be movable in an axial direction of a rotation axis so as to obtain a first position at which a power input shaft and a power output shaft that are rotatable around the rotation axis respectively are connected and a second position at which the power input shaft and the power output shaft that are rotatable around the rotation axis respectively are disconnected, wherein each of the first thrust force amplification mechanism and the second thrust force amplification mechanism is configured to have a pair of rotary members that is rotatable around the rotation axis, the pair of rotary members is configured to be axially separated by being rotated relative to each other, and one of the pair of rotary members causes the switching member of each connection/disconnection mechanism to move in one direction of the rotation axis, wherein a rotation suppression torque is able to be added to the other one of the pair of rotary members by the first control clutch through the first actuator, wherein a rotation suppression torque is able to be added to the other one of the pair of rotary members by the second control clutch through the second actuator, wherein one of the pair of rotary members of each of the first thrust force amplification mechanism and the second thrust force amplification mechanism is connected to a rotary member whose rotating speed is increased in proportion to a vehicle speed in a non-rotatable relatively manner respectively, and wherein at least one of the first connection/disconnection mechanism and the second connection/disconnection mechanism is provided with a synchronization mechanism for synchronizing the rotations of the power input shaft and the power output shaft.

2 . The vehicle four-wheel drive apparatus according to claim 1 , wherein each of the first thrust force amplification mechanism and the second thrust force amplification mechanism is a ball cam or a rotary cam.

3 . The vehicle four-wheel drive apparatus according to claim 1 , wherein each of the first actuator and the second actuator is configured of an electromagnetic solenoid, a motor mechanism or a hydraulic mechanism.

4 . The vehicle four-wheel drive apparatus according to claim 1 , wherein the vehicle four-wheel drive apparatus is further provided with a fixing mechanism for maintaining the connection/disconnection states of the first connection/disconnection mechanism and the second connection/disconnection mechanism.

5 . The vehicle four-wheel drive apparatus according to claim 1 , wherein an electronic control coupling is provided in a power transmission path between the propeller shaft and the auxiliary drive wheels for controlling a torque transmitted to the auxiliary drive wheels.

6 . The vehicle four-wheel drive apparatus according to claim 5 , wherein:
the vehicle four-wheel drive apparatus is further provided with a control device for switching connection or disconnection of the first connection/disconnection mechanism and the second connection/disconnection mechanism; and in a case where each of the first connection/disconnection mechanism and the second connection/disconnection mechanism is provided with the synchronization mechanism, when the first connection/disconnection mechanism and the second connection/disconnection mechanism are to be connected during traveling, the control device releases the electronic control coupling and actuates the first actuator and the second actuator.

7 . The vehicle four-wheel drive apparatus according to claim 5 , wherein:
the vehicle four-wheel drive apparatus is further provided with a control device for switching connection or disconnection of the first connection/disconnection mechanism and the second connection/disconnection mechanism; and in a case where only one of the first connection/disconnection mechanism and the second connection/disconnection mechanism is provided with the synchronization mechanism, when the first connection/disconnection mechanism and the second connection/disconnection mechanism are to be connected during traveling, the control device engages the electronic control coupling and actuates the first actuator and the second actuator.

Assignees

• Toyota Motor Co Ltd

Inventors

• Yoshimura Takahiro
• Horie Ryota

Classifications

• B60K17/348

  having differential means for driving one set of wheels, e.g. the front, at one speed and the other set, e.g. the rear, at a different speed (B60K17/346 takes precedence) · CPC title

• B60K17/344 Primary

  having a transfer gear · CPC title

• B60K23/0808

  for varying torque distribution between driven axles, e.g. by transfer clutch · CPC title

• B60K2023/085

  automatically actuated · CPC title

• B60K2023/0833

  for adding torque to the rear wheels · CPC title