Hydraulic control unit for a limited slip differential

Patent metadata

Field	Value
Publication number	US-10330187-B2
Application number	US-201615290679-A
Country	US
Kind code	B2
Filing date	Oct 11, 2016
Priority date	Apr 11, 2014
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

A hydraulic control unit that delivers hydraulic fluid to a limited slip differential includes a hydraulic control unit housing, a sump and a motor. The hydraulic control unit housing has an accumulator housing portion that houses a biasing assembly and a piston. The sump is defined in the hydraulic control unit housing and at least partially occupies a common space with the accumulator housing portion. The motor is configured to pump fluid into an accumulator chamber of the accumulator housing portion. The fluid pumped into the accumulator housing portion at least partially collapses the biasing assembly and introduces a pre-charge into the hydraulic control unit. The biasing assembly is configured to expand and urge the piston in a first direction resulting in fluid being communicated from the hydraulic control unit and into the limited slip differential.

First claim

What is claimed is:

1. A hydraulic control unit that delivers hydraulic fluid to a limited slip differential, the hydraulic control unit comprising:
a hydraulic control unit housing having an accumulator housing portion and a housing manifold portion that collectively house a biasing assembly and a piston, the housing manifold portion forming an accumulator chamber with the piston, wherein the biasing assembly further comprises:
A first biasing member having a first spring rate;
A second biasing member having a second spring rate, wherein the first and second spring rates are distinct; and
A guide rod that supports the first and second biasing members and minimizes buckling thereof;

a sump defined in the hydraulic control unit housing and that at least partially occupies a common space with the accumulator housing portion; and
A pump that pumps fluid into the accumulator chamber of the accumulator housing portion;
wherein the fluid pumped into the accumulator housing portion at least partially collapses the biasing assembly and introduces a pre-charge into the hydraulic control unit, wherein the biasing assembly is configured to subsequently expand after the pre-charge and urge the piston in a first direction resulting in fluid being communicated from the hydraulic control unit and into the limited slip differential.

2. The hydraulic control unit of claim 1 wherein the hydraulic control unit housing further comprises:
a hydraulic control unit housing mounting structure having first and second receiving bores that both define a first diameter and wherein a first pair of first fasteners that both define a second diameter, less than the first diameter, couple the hydraulic control unit to an axle housing that houses the limited slip differential.

3. The hydraulic control unit of claim 2 , further comprising a hydraulic coupling that has a first end that is received by a first receiving bore defined on the hydraulic control unit housing.

4. The hydraulic control unit of claim 3 wherein the hydraulic coupling has a second end that is configured to be received by a second receiving bore defined on the limited slip differential.

5. The hydraulic control unit of claim 4 , further comprising at least one o-ring disposed around the second end that sealingly engages the second receiving bore.

6. The hydraulic control unit of claim 5 wherein the hydraulic coupling is configured to extend through a hydraulic coupler receiving bore defined in the axle housing.

7. The hydraulic control unit of claim 6 wherein the axle housing defines an inner diameter that is greater than an outer diameter of the hydraulic coupling, wherein the hydraulic coupling is permitted to locate at a plurality of positions relative to the inner diameter of the axle housing during assembly of the hydraulic control unit to the limited slip differential to accommodate a corresponding plurality of positions of the differential relative to the axle housing.

8. The hydraulic control unit of claim 2 , further comprising first and second mounting members that respectively comprise (i) third and fourth receiving bores, and (ii) first and second mounting passages, wherein a second pair of first fasteners respectively extend through the third and fourth receiving bores coupling the hydraulic control unit to the axle housing.

9. The hydraulic control unit of claim 8 , further comprising a pair of second fasteners that extend through the first and second mounting passages and mate with the hydraulic control unit housing to couple the first and second mounting members thereat.

10. The hydraulic control unit of claim 2 wherein the hydraulic control unit is pre-filled with hydraulic fluid prior to coupling to the axle housing.

11. A hydraulic control unit that delivers hydraulic fluid to a limited slip differential, the hydraulic control unit comprising:
a hydraulic control unit housing having an accumulator housing portion and a housing manifold portion that collectively house a biasing assembly and a piston, the housing manifold portion forming an accumulator chamber with the piston;
a sump defined in the hydraulic control unit housing and that at least partially occupies a common space with the accumulator housing portion;
a pump that pumps fluid into the accumulator chamber of the accumulator housing portion; and
a hydraulic coupling that has (i) a first end that is received by a first receiving bore defined on the hydraulic control unit housing, and (ii) a second end that is configured to extend through a hydraulic coupler receiving bore define in the axle housing and be received by a second receiving bore defined on the limited slip differential, the second end having an o-ring disposed therearound that sealingly engages the second receiving bore;
wherein the fluid pumped into the accumulator chamber of the accumulator housing portion at least partially collapses the biasing assembly and introduces a pre-charge into the hydraulic control unit, wherein the biasing assembly is configured to subsequently expand after the pre-charge and urge the piston in a first direction resulting in fluid being communicated from the hydraulic control unit and into the limited slip differential.

12. The hydraulic control unit of claim 11 , further comprising at least one o-ring disposed around the second end that sealingly engages the second receiving bore.

13. The hydraulic control unit of claim 11 wherein the axle housing defines an inner diameter that is greater than an outer diameter of the hydraulic coupling, wherein the hydraulic coupling is permitted to locate at a plurality of positions relative to the inner diameter of the axle housing during assembly of the hydraulic control unit to the limited slip differential to accommodate a corresponding plurality of positions of the differential relative to the axle housing.

14. The hydraulic control unit of claim 11 wherein the hydraulic control unit housing further comprises:
a hydraulic control unit housing mounting structure having first and second receiving bores that both define a first diameter and wherein a first pair of first fasteners that both define a second diameter, less than the first diameter, couple the hydraulic control unit to an axle housing that houses the limited slip differential.

15. The hydraulic control unit of claim 14 , further comprising first and second mounting members that respectively comprise (i) third and fourth receiving bores, and (ii) first and second mounting passages, wherein a second pair of first fasteners respectively extend through the third and fourth receiving bores coupling the hydraulic control unit to the axle housing, wherein the third receiving bore is transverse to the first mounting passage and the fourth receiving bore is transverse to the second mounting passage.

16. The hydraulic control unit of claim 15 , further comprising a pair of second fasteners that extend through the first and second mounting passages and mate with the hydraulic control unit housing to couple the first and second mounting members thereat.

17. The hydraulic control unit of claim 11 wherein the hydraulic control unit is pre-filled with hydraulic fluid prior to coupling to the axle housing.

18. The hydraulic control unit of claim 11 wherein the biasing assembly further comprises:
a first biasing member having a first spring rate;
a second biasing member having a second spring rate, wherein the first and second spring rates are distinct; and
a guide rod that supports the first and second biasing members.

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Assignees

• Eaton Corp

Inventors

• Fisher Daniel P
• Edler Andrew N
• Besemer Scott M
• Oesch Jeffrey A
• Fox Matthew G

Classifications

• F16H2057/02086

  Measures for reducing size of gearbox, e.g. for creating a more compact transmission casing · CPC title

• F16H2057/02026

  Connection of auxiliaries with a gear case; Mounting of auxiliaries on the gearbox · CPC title

• F15B2201/51

  Pressure detection · CPC title

• F15B2201/21

  using springs · CPC title

• F16H48/32 Primary

  using fluid pressure actuators · CPC title