Differential limiting device for vehicle

Patent metadata

Field	Value
Publication number	US-10234009-B2
Application number	US-201715714417-A
Country	US
Kind code	B2
Filing date	Sep 25, 2017
Priority date	Oct 6, 2016
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

In a differential limiting device for a vehicle, when rotary motion of an electric motor is converted by a screw mechanism into linear motion of a nut member in a direction of a first axis C 1 of a side gear shaft, and a piston mounted on the nut member is moved in a direction opposite to a direction to depress frictional engagement elements, the piston and a clutch drum are relatively non-rotatably engaged. Therefore, differential rotation of a pair of side gears is mechanically limited. Thus, rotation of one electric motor makes it possible to generate differential limiting torque for limiting differential rotation of the pair of side gears in a rear-wheel differential device.

First claim

What is claimed is:

1. A differential limiting device for a vehicle,
the differential limiting device configured to limit differential rotation of a pair of side gears provided in a differential device,
the differential limiting device comprising:
a clutch hub coupled to one of a differential case of the differential limiting device and a side gear shaft;
a clutch drum coupled to the other of the differential case and the side gear shaft;
a friction clutch including a plurality of frictional engagement elements and a piston;
an actuator; and
a screw mechanism including a screw shaft member and a nut member that are screwed together,

wherein the side gear shaft is coupled to the side gear,
the plurality of frictional engagement elements include first frictional engagement elements and second frictional engagement elements,
the first frictional engagement elements are configured to be relatively non-rotatably engaged with the clutch drum,
the second frictional engagement elements are configured to be relatively non-rotatably engaged with the clutch hub,
the first frictional engagement elements and the second frictional engagement elements are configured to overlap with each other so as to be in friction contact with each other,
the screw mechanism is configured to convert rotary motion of the actuator into linear motion of the nut member in an axial direction of the side gear shaft when a screw member is rotated about an axis of the side gear shaft by the actuator,
the screw member is one of the screw shaft member and the nut member,
the piston is configured to depress the plurality of frictional engagement elements, the piston is configured to rotate relative to the nut member about the axis of the side gear shaft,
the piston is configured to be unable to move relative to the nut member in the axial direction of the side gear shaft,
the piston is configured to be unable to rotate relative to a first clutch component about the axis of the side gear shaft,
the piston is configured to move relative to the first clutch component in the axial direction,
the piston is configured to be relatively non-rotatably engaged with a second clutch component when the piston is moved in a direction opposite to a direction in which the piston depresses the frictional engagement elements, and
the first clutch component is one of the clutch hub and the clutch drum, and the second clutch component is the other of the clutch hub and the clutch drum.

2. The differential limiting device according to claim 1 , wherein
the piston is spline-fitted to the first clutch component such that the piston cannot rotate relative to the first clutch component, and is configured to move relative to the first clutch component in the axial direction of the side gear shaft,
the piston includes first meshing teeth, and the second clutch component includes second meshing teeth, and
the first meshing teeth mesh with the second meshing teeth when the piston is moved by the nut member in the direction opposite to the direction in which the piston depresses the frictional engagement elements.

3. The differential limiting device according to claim 1 , wherein
the screw member is the nut member, the nut member is supported by the side gear shaft such that the nut member rotates about the axis of the side gear shaft, and the screw shaft member is supported by the side gear shaft such that the screw shaft member cannot move in the axial direction of the side gear shaft, and cannot rotate about the axis of the side gear shaft.

4. The differential limiting device according to claim 1 , wherein
the screw member is the screw shaft member, the nut member is supported by the side gear shaft such that the nut member cannot rotate about the axis of the side gear shaft, and the screw shaft member is supported by the side gear shaft such that the screw shaft member cannot move in the axial direction of the side gear shaft and rotates about the axis of the side gear shaft.

5. The differential limiting device according to claim 1 , wherein
the actuator is coupled to the screw mechanism via a worm gear.

6. The differential limiting device according to claim 1 , wherein
the nut member and the screw shaft member are screwed together via a plurality of balls.

Assignees

• Toyota Motor Co Ltd

Inventors

• Imafuku Mizuki

Classifications

• F16H2048/343

  using a rotary motor · CPC title

• F16D13/52

  Clutches with multiple lamellae {; Clutches in which three or more axially moveable members are fixed alternately to the shafts to be coupled and are pressed from one side towards an axially-located member (F16D13/385 takes precedence)} · CPC title

• B60K17/02

  characterised by arrangement, location, or kind of clutch · CPC title

• F16D2023/123

  Clutch actuation by cams, ramps or ball-screw mechanisms · CPC title

• F16D23/00

  Details of mechanically-actuated clutches not specific for one distinct type · CPC title