METHOD OF REDUCING TORQUE RIPPLE IN HYDRAULIC MOTORS

• US 20100162693A1
• Filed: 12/31/2008
• Published: 07/01/2010
• Est. Priority Date: 12/31/2008
• Status: Abandoned Application

• Current Assignee: Milwaukee School Of Engineering, Evonik RohMax Additives GmbH (Rag-Stiftung)
• Original Assignee: Milwaukee School Of Engineering
• Inventors: Michael, Paul W., Herzog, Steven N.
• Application Number:
  US12/347,608
• Publication Number:
  US 20100162693A1
• Time in Patent Office: Days
• US Class Current: 60/327
• CPC Class Codes: C10M 171/02 Specified values of viscosity or viscosity index
• CPC Class Codes: C10M 2203/1006 used as base material
• CPC Class Codes: C10N 2020/02 Viscosity; Viscosity index
• CPC Class Codes: C10N 2020/04 Molecular weight; Molecular weight distribution
• CPC Class Codes: C10N 2030/76 Reduction of noise, shudder, or vibrations
• CPC Class Codes: C10N 2040/08 Hydraulic fluids, e.g. brake-fluids

Abstract

Torque Ripple is reduced in hydraulic system by operating with a hydraulic fluid having a VI of at least 130.

Claims

1. A method of reducing torque ripple in a hydraulic system, comprising:

operating a hydraulic system with a hydraulic fluid having a VI of at least 130.

2. The method according to claim 1, wherein said reduction in torque ripple is at least 3% compared to the power output of a hydraulic system using a monograde hydraulic fluid having a VI of about 100, operating at the same pressure and temperature with identical mechanical power input from the engine or electric motor.

3. The method according to claim 1, wherein said reduction in torque ripple is at least 5% compared to the power output of a hydraulic system using a monograde hydraulic fluid having a VI of about 100, operating at the same pressure and temperature with identical mechanical power input from the engine or electric motor.

4. The method according to claim 1, wherein the pressure provided by a unit providing hydraulic power is in the range of 50 to 700 bar.

5. The method according to claim 1, wherein the pressure provided by a unit providing hydraulic power is in the range of 150 to 350 bar.

6. The method according to claims 1, wherein the hydraulic fluid has a VI of at least 150.

7. The method according to claim 1, wherein the hydraulic fluid has a VI of at least 180.

8. The method according to claim 1, wherein the hydraulic fluid is a NFPA double viscosity grade, triple viscosity grade, quadra viscosity grade, or penta viscosity grade hydraulic fluid.

9. The method according to claim 1, wherein the hydraulic fluid is obtained by mixing a base fluid and a polymeric viscosity index improver.

10. The method according to claim 1, wherein the hydraulic fluid comprises at least 60% by weight of at least one base fluid.

11. The method according to claim 1, wherein the hydraulic fluid comprises at least 60% by weight of at least one base fluid having a viscosity index of 120 or less.