Hydraulically-driven concrete finishing trowel having hydraulic fluid cooling system and method
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
E01C-019/42
E04F-021/24
E01C-019/22
출원번호
US-0019493
(2016-02-09)
등록번호
US-9631378
(2017-04-25)
발명자
/ 주소
Grahl, Scott
Jenkins, Michael
출원인 / 주소
Wacker Neuson Production Americas LLC
대리인 / 주소
Boyle Fredrickson, S.C.
인용정보
피인용 횟수 :
1인용 특허 :
11
초록▼
A hydrostatically power self-propelled concrete finishing trowel has at least two coolers in a cooling system of the machine's hydraulic circuit. In the most typical case in which the first cooler is a closed loop oil cooler, the second cooler may take the form of an open loop oil cooler disposed in
A hydrostatically power self-propelled concrete finishing trowel has at least two coolers in a cooling system of the machine's hydraulic circuit. In the most typical case in which the first cooler is a closed loop oil cooler, the second cooler may take the form of an open loop oil cooler disposed in a flow path connecting one or more low-pressure outlets of the hydrostatic drive system to a reservoir. The closed loop oil cooler actively drops the temperature within the trowel's hydrostatic drive system, while the open loop oil cooler supplements that cooling by reducing the oil temperature in the reservoir.
대표청구항▼
1. A concrete finishing trowel comprising: a frame;at least first and second rotor assemblies extending downwardly from the frame, each of the rotor assemblies having a shaft that supports a plurality of blades;an engine; anda hydraulic circuit including a reservoir and a hydrostatic drive system th
1. A concrete finishing trowel comprising: a frame;at least first and second rotor assemblies extending downwardly from the frame, each of the rotor assemblies having a shaft that supports a plurality of blades;an engine; anda hydraulic circuit including a reservoir and a hydrostatic drive system that is coupled to the engine, to the rotor assemblies, and to the reservoir, the hydrostatic drive system comprising including a hydraulic motor that is coupled to at least one of the rotor assemblies,a drive pump that is driven by the engine and that delivers pressurized fluid to the hydraulic motor, anda charge pump that is connected to the reservoir and that delivers hydraulic fluid to the drive pump, whereinthe hydraulic circuit further comprises first and second coolers that cool hydraulic fluid flowing through the hydrostatic drive system, wherein the first cooler is a closed loop cooler located in a flow path connecting an outlet of the motor to an inlet of the drive pump, and the second cooler is an open loop cooler in a flow path connecting the hydrostatic drive system to the reservoir. 2. The concrete finishing trowel of claim 1, wherein each of the coolers is a hydraulic fluid to air heat exchanger. 3. The concrete finishing trowel of claim 1, wherein the hydraulic motor is a first drive motor coupled to the first rotor assembly,the drive pump is a first drive pump that delivers pressurized fluid to the first drive motor,the hydrostatic drive system further comprises a second drive motor coupled to the second rotor assembly and a second drive pump that delivers pressurized fluid to the second drive motor,the charge pump delivers hydraulic fluid to both the first and second drive pumps, and whereinthe closed loop cooler is in a flow path connecting an outlet of each of the driver motors to an inlet of each of the drive pumps. 4. The concrete finishing machine of claim 1, further comprising an auxiliary pump and an auxiliary circuit that selectively couples hydraulically actuated devices of the concrete finishing trowel to the auxiliary pump and to a drain flow path, and wherein the drain flow path is fluidically coupled to an inlet of the open loop cooler. 5. The concrete finishing machine of claim 4, wherein the auxiliary circuit is hydraulically coupled to at least one of a fight/left steering cylinder, a forward/reverse steering cylinder, and a pitch control cylinder. 6. The concrete finishing machine of claim 1, wherein the open loop cooler receives hydraulic fluid from a case drain of the hydrostatic drive system. 7. The concrete finishing machine of claim 1, further comprising a bypass valve that permits hydraulic fluid flowing out of the hydrostatic drive system to bypass the open loop cooler when the hydraulic fluid temperature is beneath a designated value. 8. A concrete finishing trowel, comprising: (A) a frame;(B) at least first and second rotor assemblies extending downwardly from the frame, each of the rotor assemblies having a shaft that supports a plurality of blades;(C) an engine; and(D) a hydraulic circuit including (1) a reservoir,(2) a hydrostatic drive system that is coupled to the engine, to the rotor assemblies, and to the reservoir, the hydrostatic drive system comprising including (a) a first hydraulic drive motor that is coupled to the first rotor assembly,(b) a first drive pump that is driven by the engine and that delivers pressurized fluid to the first drive motor,(c) a second hydraulic drive motor that is coupled to the second rotor assembly,(d) a second drive pump that is driven by the engine and that delivers pressurized fluid to the second drive motor, and(e) a charge pump that is connected to the reservoir and that delivers hydraulic fluid to the first and second drive pumps;(3) a closed loop oil cooler located in a flow path connecting outlets of the first and second drive motors to inlets of the first and second drive pumps; and(4) an open loop oil cooler in a flow path connecting the hydrostatic drive system to the reservoir. 9. The concrete finishing trowel of claim 8, further comprising an auxiliary pump and an auxiliary circuit that selectively couples hydraulically actuated devices of the concrete finishing trowel to the auxiliary pump and to a drain flow path, and wherein the drain flow path is fluidically coupled to an inlet of the open loop oil cooler. 10. The concrete finishing trowel of claim 8, wherein the open loop oil cooler receives hydraulic fluid from a case drain of the hydrostatic drive system. 11. The concrete finishing trowel of claim 8, further comprising a bypass valve that permits hydraulic fluid flowing out of the hydrostatic drive system to bypass the open loop oil cooler when the hydraulic fluid temperature is beneath a designated value. 12. A method of operating a hydrostatically driven concrete finishing machine, the concrete finishing machine having an engine and first and second rotatable rotor assemblies that support the concrete finishing machine on a surface to be finished, the method comprising: driving a drive pump of a hydrostatic drive system via operation of the engine,delivering pressurized hydraulic fluid to a drive motor of the hydrostatic drive system from the drive pump, thereby causing the drive motor to drive at least one of the rotor assemblies to rotate;delivering hydraulic fluid from the drive motor to the drive pump;draining leakage hydraulic fluid from the hydrostatic drive system;using a charge pump, pumping make-up hydraulic fluid to the hydrostatic drive system;cooling hydraulic fluid flowing through the hydrostatic drive system in first and second coolers, wherein the cooling step comprises cooling hydraulic fluid within a closed loop circuit of the hydrostatic drive system via the first cooler and cooling hydraulic fluid drained from the hydrostatic drive system via the second cooler. 13. The method of claim 12, wherein the cooling step maintains the temperature of hydraulic fluid within the hydrostatic drive system beneath 200° F. throughout at least substantially an entire operating range of the concrete finishing machine. 14. The method of claim 12, further comprising controlling hydraulic fluid flow to and from hydraulically actuated devices of the concrete finishing machine via operation of an auxiliary hydraulic circuit, and further comprising cooling hydraulic fluid flowing from the auxiliary hydraulic circuit via the second cooler. 15. The method of claim 12, wherein the drive motor is a first drive motor coupled to the first rotor assembly and the drive pump is a first drive pump that delivers pressurized fluid to the first drive motor to drive the first rotor assembly to rotate, and further comprising: driving a second drive pump of the hydrostatic drive system via operation of the engine,delivering pressurized hydraulic fluid to a second drive motor of the hydrostatic drive system from the second drive pump, thereby causing the second drive motor to drive the second rotor assembly to rotate; anddelivering hydraulic fluid from the second drive motor to the second drive pump. 16. The method of claim 15, wherein the first cooler is located in a shared flow path coupling outlets of both of the first and second drive motors to inlets of both of the first and second drive pumps. 17. The method of claim 12, further comprising causing fluid draining from the hydrostatic drive system to bypass the second cooler if the temperature of the hydraulic fluid is beneath a designated temperature.
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이 특허에 인용된 특허 (11)
Lickel, Timothy J.; Grahl, Scott, Concrete trowel transport system.
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