Final drive assembly with differential lock

• US 20040053725A1
• Filed: 09/22/2003
• Published: 03/18/2004
• Est. Priority Date: 10/04/2000
• Status: Active Grant

• Current Assignee: Magna Steyr Fahrzeugtechnik AG & Company KG (Magna International Incorporated)
• Original Assignee: Magna Steyr Fahrzeugtechnik AG & Company KG (Magna International Incorporated)
• Inventors: Pecnik, Herman
• Granted Patent: US 6,935,983 B2
• Time in Patent Office: Days
• US Class Current: 475/230
• CPC Class Codes: B60K 17/346 the transfer gear being a differential gear
• CPC Class Codes: F16H 2048/106 characterised by two sun gears
• CPC Class Codes: F16H 48/05 Multiple interconnected differential sets
• CPC Class Codes: F16H 48/10 with orbital spur gears
• CPC Class Codes: F16H 48/22 using friction clutches or brakes

Abstract

Axle-drive unit for a motor vehicle which contains a first and a second differential (18, 19) in a driven housing (22), the two differentials (18, 19) being spur-gear-type planetary gears with parallel axes, the sun wheels (32, 43) of which are in each case connected in terms of drive to the half axles (8, 9) of the first driven axle, and planet wheels (36, 38) of the two differentials (18, 19) meshing with their common ring gear (35). In order to achieve locking both of the axle differential (18) and of the longitudinal differential (19) with minimal outlay on construction, the housing (22) has a machined inner surface (50) which surrounds the ring gear (35) with little clearance, the ring gear is so thin in the radial direction that it is deformed in a lobe-like manner by the radial component of the tooth forces exerted by the planet wheels (31, 36), its outer circumferential surface (60) thereby being placed against the inner surface (50) of the housing (22) in a manner producing friction at least locally, as a result of which a braking moment acts on the ring gear.

Claims

1. An axle-drive unit for a motor vehicle having a first and a second driven axle which comprises a first and a second differential (18, 19) in a housing driven by an engine/transmission block (1), the first differential (18) dividing the torque fed to it between a first half axle (9) of the first driven axle (8, 9) and the second differential (19), and the latter furthermore dividing the torque fed to it between a second half axle (8) of the first driven axle (8, 9) and a power take-off (7) for the second driven axle (16, 17), the two differentials (18, 19) being spur-gear-type planetary gears with parallel axes, the sun wheels (32, 43) of which are in each case connected in terms of drive to the half axles (8, 9) of the first driven axle, and planet wheels (36, 38) of the two differentials (18, 19) meshing with their common ring gear (35), the one planet carrier (23) being connected in a rotationally fixed manner to the housing and the other planet carrier (40) being connected in terms of drive to the power take-off (7) for the second driven axle, wherein

a) the housing (22) has a machined inner surface (50) which surrounds the ring gear (35) with little clearance (63),

b) the ring gear (35) is so thin in the radial direction that it is deformed in a lobe-like manner (35*) by the radial component (F_R) of the tooth forces exerted by the planet wheels (31, 36),

c) its outer circumferential surface (60) thereby being placed against the inner surface (50) of the housing (22) in a manner producing friction at least locally, and a braking moment thereby acting on the ring gear (35).

2. The axle-drive unit as claimed in claim 1 having a driven housing (22) which is divided in a radial plane into two housing parts (23, 24), wherein that part of the housing (24) which forms the inner surface (50) rises above the radial plane of separation and has an undercut (54) between this part and the radial surface (51).

3. The axle-drive unit as claimed in claim 2, wherein the housing part (24) with the inner surface (50) has radial cooling ribs (62) on its outside.

4. The axle-drive unit as claimed in claim 1, wherein the circumferential surface (60) of the ring gear (35) has machined, raised zones (61) of limited axial width.