Locking differential assembly

Patent metadata

Field	Value
Publication number	US-2017191556-A1
Application number	US-201715465511-A
Country	US
Kind code	A1
Filing date	Mar 21, 2017
Priority date	Jan 23, 2013
Publication date	Jul 6, 2017
Grant date	—

Abstract

A locking differential assembly includes a differential case defining an axis of rotation and a gear chamber. A first side gear is at a first end of the differential case. A second side gear is at a second end of the differential case opposite the first end for selectable rotation relative to the differential case. A solenoid is at the first end. The solenoid is directly wound onto a stator.

First claim

What is claimed is:

1 . A locking differential assembly, comprising:
a differential case defining an axis of rotation and a gear chamber; a first side gear disposed at a first end of the differential case for selectable relative rotation thereto; a second side gear disposed at a second end of the differential case opposite the first end for selectable rotation relative to the differential case; and a solenoid disposed at the first end, wherein the solenoid is directly wound onto a stator.

2 . The locking differential assembly as defined in claim 1 , the stator comprising:
an annular wall having a longitudinal axis coaxial with the axis of rotation; a first stator annular flange extending radially from the annular wall to a first outer diameter; and a second stator annular flange extending from the annular wall spaced from the first stator annular flange, wherein:
the second stator annular flange is frustoconical with an inner base annular surface opposite the first stator annular flange and an outer base annular surface distal to the first stator annular flange;
the inner base annular surface has an outer edge diameter equal to the first outer diameter and the outer base annular surface has a second outer diameter greater than the first outer diameter;
the first stator annular flange, the annular wall and the second stator annular flange define an integral bobbin for the solenoid;
the stator is formed from a ferromagnetic material; and
the differential case is rotatable relative to the stator about the axis of rotation.

3 . The locking differential assembly as defined in claim 1 , further comprising:
at least two pinion gears rotatably supported in the gear chamber each of the at least two pinion gears in meshing engagement with the first side gear and the second side gear; a plunger selectably magnetically actuatable by the solenoid; and a lock ring connected to the plunger, the lock ring selectably engagable with the first side gear or the second side gear to selectably prevent the first side gear and the second side gear from rotating relative to the differential case.

4 . The locking differential assembly as defined in claim 3 wherein the plunger comprises:
a ferromagnetic cylindrical body, including:
a cylindrical body axis defined by the ferromagnetic cylindrical body to be aligned with the axis of rotation;
an inner wall having an annular bevel at a beveled end of the ferromagnetic cylindrical body;
an outer wall having a plunger outer diameter;
an annular plunger flange defined at a plunger end distal to the beveled end wherein the annular plunger flange has a plunger flange diameter smaller than the plunger outer diameter;
an annular notch defined by the ferromagnetic cylindrical body and the annular plunger flange;
a plurality of relay rod attachment bores defined in the ferromagnetic cylindrical body; and
a plurality of relay rod access slots each defined in the beveled end of the ferromagnetic cylindrical body at each relay rod attachment bore, wherein the relay rod attachment bore is substantially centered in the relay rod access slot, wherein a shortest distance between the relay rod access slot and the annular notch is equal to a lock ring thickness parallel to the axis of rotation.

5 . The locking differential assembly as defined in claim 4 wherein the stator includes:
an annular wall having a longitudinal axis coaxial with the axis of rotation;
a first stator annular flange extending radially from the annular wall to a first outer diameter; and
a second stator annular flange extending from the annular wall spaced from the first stator annular flange, and wherein a spacer is disposed between the plunger and the differential case to prevent the annular bevel of the inner wall from contacting the second stator annular flange.

6 . The locking differential assembly as defined in claim 5 wherein the spacer is a threaded rod adjustably screwed into the plunger to set a predetermined gap between the annular bevel and the second stator annular flange.

7 . The locking differential assembly as defined in claim 5 wherein the spacer is a plurality of spaced raised bosses on the beveled end of the ferromagnetic cylindrical body.

8 . The locking differential assembly as defined in claim 5 , further comprising at least two relay rods each connected to the plunger and to the lock ring to cause the lock ring to remain a fixed predetermined distance from the plunger, wherein the at least two relay rods each include:
a cylindrical rod portion having two ends, the cylindrical rod portion defining a longitudinal rod axis at a center of the cylindrical rod portion; a first post and a second post each having a smaller diameter than the cylindrical rod portion defined at a respective one of the two ends, the first post and the second post each concentric with the cylindrical rod portion; and an annular groove defined on the first post and the second post, wherein the first and second posts are substantially identical and the relay rod is symmetrical end-to-end, wherein the first post is retained in a respective relay rod attachment bore by a retention ring disposed in the annular notch of the plunger protruding into the annular groove of the first post.

9 . The locking differential assembly as defined in claim 3 , further comprising:
side gear dogs defined on an outside diameter of the second side gear parallel to the axis of rotation; complementary dogs defined around an inside surface of the lock ring, the complementary dogs selectably engagable with the side gear dogs by translating the lock ring along the axis of rotation from a disengaged position to an engaged position; a spring disposed between the differential case and the lock ring to bias the lock ring toward the disengaged position; and a plurality of lugs defined on an outside surface of the lock ring, each lug to slide in a respective complementary slot defined in the differential case to guide the lock ring translation between the engaged position and the disengaged position and to prevent rotation of the lock ring relative to the differential case; wherein the second side gear is substantially prevented from rotating relative to the differential case when the lock ring is in the engaged position, and the second side gear is free to rotate relative to the differential case when the lock ring is in the disengaged position and wherein the lock ring has a lock ring thickness parallel to the axis of rotation.

10 . The locking differential assembly as defined in claim 9 wherein the lock ring further includes extension tabs on a quantity of the lugs equal to a quantity of relay rods, the extension tabs each having a relay rod attachment hole therethrough wherein each relay rod is retained in the respective relay rod attachment hole by a clip installed in the annular groove of the respective second post.

11 . A locking differential assembly, comprising:
a differential case defining an axis of rotation and a gear chamber; a first side gear disposed at a first end of the differential case for selectable relative rotation thereto; a second side gear disposed at a second end of the differential case opposite the first end for selectable rotation relative to the differential case; a solenoid disposed at the first end, the solenoid connected to a lock ring to actuate the lock ring by applying electrical power to the solenoid, wherein the lock ring is selectably engagable with the second side gear to selectably prevent the second side gear from rotating relative to the differential case; and a plunger selectably magnetically actuatable by the solenoid, wherein:
the plunger is

Assignees

• Eaton Corp

Inventors

• Cochren Steven J
• Frazier Daniel Stanley
• Hillman Chad Robert
• Vandervoort John Kimmel

Classifications

• F16H48/40

  characterised by features of the rotating cases · CPC title

• F16H2048/346

  using a linear motor · CPC title

• F16H48/24

  using positive clutches or brakes · CPC title

• F16H48/08 Primary

  comprising bevel gears · CPC title

• F16H48/34 Primary

  using electromagnetic or electric actuators · CPC title