Hbrid machine with hydraulic drive device

• US 20030097837A1
• Filed: 11/01/2002
• Published: 05/29/2003
• Est. Priority Date: 05/19/2000
• Status: Active Grant

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Inoueo, Hiroaki, Hiraki, Hikosaburo, Itow, Koichiro
• Granted Patent: US 6,962,050 B2
• Time in Patent Office: Days
• US Class Current: 60/486
• CPC Class Codes: B60L 1/20 Energy regeneration from auxiliary equipment
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: E02F 9/2217 with energy recovery arrangements, e.g. using accumulators, flywheels
• CPC Class Codes: E02F 9/2228 including an electronic controller
• CPC Class Codes: E02F 9/2282 Systems using center bypass type changeover valves
• CPC Class Codes: E02F 9/2285 Pilot-operated systems
• CPC Class Codes: E02F 9/2292 Systems with two or more pumps
• CPC Class Codes: F15B 1/024 used as a supplementary power source, e.g. to store energy in idle periods to balance pump load
• CPC Class Codes: F15B 11/17 using two or more pumps
• CPC Class Codes: F15B 21/08 Servomotor systems incorporating electrically operated control means F15B21/02, F15B21/065 take precedence
• CPC Class Codes: F15B 21/14 Energy-recuperation means
• CPC Class Codes: F15B 2211/20576 with multiple pumps
• CPC Class Codes: F15B 2211/212 the pressure sources being accumulators
• CPC Class Codes: F15B 2211/27 Directional control by means of the pressure source
• CPC Class Codes: F15B 2211/30515 Load holding valves
• CPC Class Codes: F15B 2211/6309 the pressure being a pressure source supply pressure
• CPC Class Codes: F15B 2211/6313 the pressure being a load pressure
• CPC Class Codes: F15B 2211/6651 Control of the prime mover, e.g. control of the output torque or rotational speed
• CPC Class Codes: F15B 2211/785 Compensation of the difference in flow rate in closed fluid circuits using differential actuators
• CPC Class Codes: F15B 7/00 Systems in which the movement produced is definitely related to the output of a volumetric pump; Telemotors
• CPC Class Codes: F15B 7/006 : Rotary pump input

Abstract

A hybrid machine with a hydraulic drive device having hydraulic actuators allowed to operate against and by external loads is provided. To this end, the hybrid machine comprises hydraulic cylinders (7), first hydraulic pumps (P1) connected, with closed circuits, to head side pressure receiving chambers (7S) and bottom side pressure receiving chambers (7L) of the hydraulic cylinders (7), and second hydraulic pumps (P2) connected, with open circuits, to the bottom side pressure receiving chambers (7L) and an external oil chamber (10), wherein the first and second hydraulic pumps (P1, P2) are connected to electric motors (M) so as to be driven.

Claims

1. A hybrid machine with a hydraulic drive device, comprising a power source (3), a generator (G) driven by power of said power source (3), electric motors (M), and a secondary battery (33) for storing electromotive force of said electric motors (M) generated by reverse driving of said electric motors (M) by external loads, said electric motors (M) receiving electric power from said generator (G) and said secondary battery (33) so as to be driven, said hybrid machine comprising:

hydraulic cylinders (7) allowed to be extended and contracted against and by external loads;

first hydraulic pumps (P1) connected, with closed circuits, to head side pressure receiving chambers (7S) and bottom side pressure receiving chambers (7L) of said hydraulic cylinders (7); and

second hydraulic pumps (P2) connected, with open circuits, to said bottom side pressure receiving chambers (7L) and an external oil chamber (10),

wherein said first and second hydraulic pumps (P1, P2) are connected to said electric motors (M) so as to be driven.

2. The hybrid machine with the hydraulic drive device according to claim 1,

wherein said first and second hydraulic pumps (P1, P2) have a relation of approximately “

A1;

A2=Q1;

(Q1+Q2)”

, where A1 is a piston pressure receiving area of said head side pressure receiving chamber (7S), A2 is a piston pressure receiving area of said bottom side pressure receiving chamber (7L), Q1 is a discharge amount per unit time of said first hydraulic pump (P1), and Q2 is a discharge amount per unit time of said second hydraulic pump (P2).

3. A hybrid machine with a hydraulic drive device, comprising a power source (3), a generator (G) driven by power of said power source (3), electric motors (M), and a secondary battery (33) for storing electromotive force of said electric motors (M) generated by reverse driving of said electric motors (M) by external loads, said electric motors (M) receiving electric power from said generator (G) and said secondary battery (33) so as to be driven, said hybrid machine comprising:

hydraulic cylinders (7) allowed to be extended and contracted against and by external loads;

first hydraulic pumps (P1) connected, with closed circuits, to head side pressure receiving chambers (7S) and bottom side pressure receiving chambers (7L) of said hydraulic cylinders (7); and

second hydraulic pumps (P2) connected, with open circuits, to said bottom side pressure receiving chambers (7L) and an external accumulator (10),

wherein said first and second hydraulic pumps (P1, P2) are connected to said electric motors (M) so as to be driven.

4. The hybrid machine with the hydraulic drive device according to claim 3,

wherein said first and second hydraulic pumps (P1, P2) are inclined shaft type piston pumps, and said electric motor (M) is of a double end output shaft type, and

wherein said first pump (P1) is connected to one of a double end output shaft, and said second first pump (P2) is connected to the other thereof.

5. The hybrid machine with the hydraulic drive device according to claim 3,

wherein said accumulator (10) is of a maximum operating pressure variable type.

6. The hybrid machine with the hydraulic drive device according to claim 3,

wherein with respect to a first passage (81) which connects said first hydraulic pump (P1) and said head side pressure receiving chamber (7S),

a drive torque of said electric motor (M) equal to a product value of

a first relief pressure determined in advance for said first passage (81), and

a sum of respective displacements per one rotation of said first and second hydraulic pumps (P1, P2)

is a maximum drive torque of said electric motor (M), and

with respect to a second passage (82) which connects said first and second hydraulic pumps (P1, P2) and said bottom side pressure receiving chamber (7L),

a drive torque of said electric motor (M) equal to a product value of

a second relief pressure determined in advance for said second passage (82), and

the sum of respective displacements per one rotation of said first and second hydraulic pumps (P1, P2)

is a maximum drive torque of said electric motor (M).

7. The hybrid machine with the hydraulic drive device according to claim 3,

wherein when at least one of said first and second hydraulic pumps (P1, P2) is a piston pump,

oil sumps (T1) which catch external leakage of oil from said piston pump,

a third hydraulic pump (P3) which sucks the oil in said oil sumps (T1), and

a first switching valve (T2) which selectably leads discharged oil from said third hydraulic pump (P3) to either one (A1, A2) of said accumulator (10) or said oil sumps (T1) are provided.

8. The hybrid machine with the hydraulic drive device according to claim 7,

wherein a variable relief valve (11X) is provided in said first and second passages (81, 82), and

wherein a second switching valve (T4) for selectively draining drain oil to either one of said accumulator (10) or said oil sumps (T1) is provided on the drain side of said variable relief valve (11X).

9. The hybrid machine with the hydraulic drive device according any one of claims 3 to 8,

wherein when a predetermined portion of said first passage (81) which connects said first hydraulic pump (P1) and said head side pressure receiving chamber (7S) is defined as a first connection point, and

a predetermined portion of said second passage (82) which connects said first and second hydraulic pumps (P1, P2) and said bottom side pressure receiving chamber (7L) is defined as a second connection point,

a passage which connects said accumulator (10) and said first connection point is provided, and a first check valve (12S) which permits only oil flow to said first connection point is provided in this passage, and

a passage which connects said accumulator (10) and said second connection point is provided, and a second check valve (12L) which permits only oil flow to said second connection point is provided in this passage.

10. The hybrid machine with the hydraulic drive device according to any one of claims 3 to 8,

wherein an on-off valve (9) which allows said second hydraulic pump (P2) and said accumulator (10) to be interrupted from each other is provided in a passage from said second hydraulic pump (P2) to said accumulator (10).

11. The hybrid machine with the hydraulic drive device according to any one of claims 3 to 8,

wherein a first on-off valve (9S) is provided in said first passage (81) which connects said first hydraulic pump (P1) and said head side pressure receiving chamber (7S), and

wherein a second on-off valve (9L) is provided in said second passage (82) which connects said first and second hydraulic pumps (P1, P2) and said bottom side pressure receiving chamber (7L).

12. The hybrid machine with the hydraulic drive device according any one of claims 3 to 8,

wherein when a predetermined portion of said first passage (81) which connects said first hydraulic pump (P1) and said head side pressure receiving chamber (7S) is defined as a first connection point, and

a predetermined portion of said second passage (82) which connects said first and second hydraulic pumps (P1, P2) and said bottom side pressure receiving chamber (7L) is defined as a second connection point,

a passage which connects said accumulator (10) and said first connection point is provided, and a first check valve (12S) which permits only oil flow to said first connection point is provided in this passage, and

a passage which connects said accumulator (10) and said second connection point is provided, and a second check valve (12L) which permits only oil flow to said second connection point is provided in this passage, further

a first on-off valve (9S) is provided between said first hydraulic pump (P1) and said first connection point in said first passage (81), and

a second on-off valve (9L) is provided between said first and second hydraulic pumps (P1, P2) and said second connection point in said second passage (82), and

a third switching valve (T5) which comprises:

a first port opening into a passage leading to said accumulator (10);

a second port opening into a passage leading to a point between said first hydraulic pump (P1) and said first on-off valve (9S) of said first passage (81); and

a third port opening into a passage leading to a point between said first and second hydraulic pumps (P1, P2) and said second on-off valve (9L) of said second passage (82),

receives oil pressure Pa of said first passage (81) as pilot pressure at a pressure receiving portion on one end side, on the other hand receives pressure Pb of said second passage (82) as pilot pressure at a pressure receiving portion on the other end side, and which comprises;

a first position which allows only said first and second ports to communicate with each other in the inside when “

Pa<

Pb”

;

a second position which allows only said first and third ports to communicate with each other in the inside when “

Pb<

Pa”

; and

a third position which allows all of said first to third ports to be interrupted from one another in the inside when “

Pa=Pb”

, is provided.

13. The hybrid machine with the hydraulic drive device according to claim 12,

wherein a controller (20) for rotating said electric motor (M) for only a predetermined time in a direction reverse to a designated rotation direction when the rotation of said electric motor (M) is started, and after the predetermined time, rotating said electric motor (M) in the designated rotation direction is provided.