Power unit

• US 7,051,840 B2
• Filed: 02/19/2002
• Issued: 05/30/2006
• Est. Priority Date: 02/19/2001
• Status: Expired due to Term

• Current Assignee: Danfoss Power Solutions Ltd. (Danfoss A/S)
• Original Assignee: Sauer-Danfoss Daikin Ltd.
• Inventors: Tani, Nobuyuki
• Primary Examiner(s): FENSTERMACHER, DAVID MORGAN
• Application Number:
  US10/276,251
• Publication Number:
  US 20030089107A1
• Time in Patent Office: 1,561 Days
• Field of Search: 184/6.1, 184/6.12, 184/6.22, 184/104.1, 184/104.2, 184/104.3, 475/72, 475/78, 475/159
• US Class Current: 184/6.12
• CPC Class Codes: F01M 1/02 using lubricating pumps pumps in general F04; lubricating pumps per se F16N
• CPC Class Codes: F16H 2037/088 Power split variators with summing differentials, with the input of the CVT connected or connectable to the input shaft
• CPC Class Codes: F16H 39/14 with cylinders carried in rotary cylinder blocks or cylinder-bearing members
• CPC Class Codes: F16H 47/04 the mechanical gearing being of the type with members having orbital motion
• CPC Class Codes: F16H 57/0412 Cooling or heating; Control of temperature
• CPC Class Codes: F16H 61/40 hydrostatic
• CPC Class Codes: F16H 61/4165 Control of cooling or lubricating

Abstract

In a power unit comprising an engine (13) and an HST (24) which are formed into an integral body, a lubricating oil for use in the engine and an operating oil of the HST (24) are commonized. After being cooled, the common oil is fed from the side of the engine (13) to the HST (24). Such arrangement suppresses the drop in viscosity of the common oil and prevents the drop in efficiency and the occurrence of seizing on the side of the HST (24).

Claims

1. A power unit which comprises an engine and a transmission mechanism including a hydro static transmission which are integrally formed and in which a common oil is shared as a lubricating oil and as an operating oil,

said power unit further comprising:

an oil feed route serially connecting said engine and said hydro static transmission,

oil feed means disposed in said oil feed route, and

cooling means disposed in said oil feed route between said engine and said hydrostatic transmission,

wherein said cooling means reduces a temperature of said common oil as said common oil flows serially from said engine to said transmission, and

wherein said oil feed means provides a uni-directional circulation of said common oil from said engine to said cooling mean and then to said hydro static transmission.

2. The power unit of claim 1, wherein said transmission mechanism (T) comprises a hydro mechanical transmission which is a combination of said hydro static transmission (24) and a mechanical transmission (23).

3. The power unit of either claim 1 or claim 2, wherein:

said cooling means comprises a heat release part (40d) provided on an outer surface of a casing (40,42), and

said oil feed route (R) is so arranged as to lie along said heat release part (40d).

4. The power unit of either claim 1 or claim 2, wherein said cooling means comprises an oil cooler (77) provided in said oil feed route (R).

5. The power unit of either claim 1 or claim 2, wherein said oil feed means comprises a charge pump (70) of said hydro static transmission (24).

6. The power unit of either claim 1 or claim 2, wherein said oil feed means comprises a lubricating pump (15) of said engine (13).

7. A power unit which comprises an engine and a transmission mechanism including a hydro static transmission which is integrally formed and in which a common oil is shared as a lubricating oil and as an operating oil,

said power unit further comprising:

an oil feed route from said engine to said hydro static transmission,

an oil reservoir connected to said oil feed route for storing said common oil,

oil feed means for successively and serially circulating said common oil among said oil reservoir, said engine and said hydro static transmission, and

cooling means disposed in said oil feed route between said engine and said hydro static transmission,

wherein said cooling means reduces a temperature of said common oil as said common oil flows successively and serially from said engine to said cooling means and then to said hydro static transmission, and

wherein said oil feed means provides a uni-directional circulation of said common oil.

8. The power unit of claim 7, wherein said transmission mechanism comprises a hydro mechanical transmission which is a combination of said hydro static transmission and a mechanical transmission.

9. The power unit of claim 7, wherein:

said cooling means comprises a heat release part provided on an outer surface of a casing, and

said oil feed route is so arranged as to lie along said heat release part.

10. The power unit of claim 7, wherein said cooling means comprises an oil cooler provided in said oil feed route.

11. The power unit of claim 7, wherein said oil feed means comprises a charge pump of said hydro static transmission.

12. The power unit of claim 7, wherein said oil feed means comprises a lubricating pump of said engine.