System for selectively bypassing fluid supply to one or more operational systems of a machine

Patent metadata

Field	Value
Publication number	US-10273962-B2
Application number	US-201615275784-A
Country	US
Kind code	B2
Filing date	Sep 26, 2016
Priority date	Sep 26, 2016
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

A hydraulic system is provided to selectively and independently route pressurized fluid to one or more operational systems of a machine. The hydraulic system is capable of switching fluid flow in operation from one of the operational systems to another of the operational systems in the event of hydraulic drive power being required by the latter one of the operational systems. The hydraulic system is also configured to continue supplying a nominal amount of fluid to support one or more auxiliary functions, for example, a lubrication system for bearings associated with the former one of the operational systems while routing the pressurized fluid to the latter one of the operational systems. A recirculation and anti-cavitation arrangement is also provided to allow recirculation of fluid to a hydraulic motor in the former one of the operational systems when pressurized fluid is being routed to the latter one of the operational systems.

First claim

What is claimed is:

1. A hydraulic system comprising:
a tank;
a pump fluidly coupled to the tank;
an inlet valve disposed in fluid communication with the pump via a first inlet passage, the inlet valve having a first biasing element configured to bias the inlet valve into a flow-blocking position;
a hydraulic motor fluidly coupled to the inlet valve via a second inlet passage, the hydraulic motor being configured to operatively rotate a fan supported thereon;
an outlet valve located downstream of the hydraulic motor and disposed in fluid communication with the hydraulic motor via a first outlet passage, the outlet valve having a second biasing element configured to bias the outlet valve into a flow-blocking position, the outlet valve being configured to selectively return fluid from the hydraulic motor to the tank via a second outlet passage;
a solenoid-operated check valve disposed parallel to the hydraulic motor and fluidly coupled with each of the first inlet passage and the second outlet passage via respective ones of a first control passage and a second control passage;
a first pilot control passage configured to branch-off from the first control passage and fluidly couple with the inlet valve for operatively biasing the inlet valve into a flow-blocking position;
a second pilot control passage configured to branch-off from the first inlet passage and fluidly couple with the inlet valve for operatively biasing the inlet valve into a flow-permitting position;
a third pilot control passage configured to branch-off from at least one of the first pilot control passage and the second control passage, the third pilot control passage fluidly coupled with the outlet valve for operatively biasing the outlet valve into a flow-blocking position; and
a fourth pilot control passage configured to branch-off from the first outlet passage and fluidly couple with the outlet valve for operatively biasing the outlet valve into a flow-permitting position.

2. The hydraulic system of claim 1 , wherein the pump is a variable displacement pump.

3. The hydraulic system of claim 1 , wherein the solenoid-operated check valve is a two-way two-position unidirectional valve operably moveable between a flow-permitting position and a flow-blocking position.

4. The hydraulic system of claim 1 , wherein each of the inlet valve and the outlet valve is a two-way two-position valve.

5. The hydraulic system of claim 1 , wherein if the solenoid-operated check valve is operatively moved into the flow-permitting position, the inlet valve is biased into the flow-permitting position by fluid pressure from the pump via the first inlet passage and the second pilot control passage for routing pressurized fluid from the pump to the hydraulic motor via the first and second inlet passages.

6. The hydraulic system of claim 5 further comprising a first orifice disposed in the first control passage, the first orifice being configured to reduce an amount of fluid being routed from the first inlet passage back to the tank via the first control passage, the second control passage and the second outlet passage when the solenoid-operated check valve is in the flow-permitting position.

7. The hydraulic system of claim 1 , wherein if the solenoid-operated check valve is operatively moved into the flow-blocking position, the inlet valve is biased into the flow-blocking position by a sum of the biasing force provided by the first biasing element associated with the inlet valve and a force of the fluid pressure from the pump via the first inlet passage, the first control passage, and the first pilot control passage such that pressurized fluid from the pump is routed from the pump to one or more operational systems disposed parallel to the inlet valve and fluidly coupled to the first inlet passage upstream of the inlet valve.

8. The hydraulic system of claim 7 , wherein when the solenoid-operated check valve is operatively moved into the flow-blocking position, the outlet valve is configured to remain closed unless a pressure of fluid in the first outlet passage and the fourth pilot control passage overcomes a sum of pressures applied by the second biasing element and a pressure of fluid in the third pilot control passage.

9. The hydraulic system of claim 1 further comprising a motor drain line configured to fluidly couple the hydraulic motor and the second outlet passage.

10. The hydraulic system of claim 9 further comprising a relief valve located upstream of the outlet valve and configured to fluidly couple with the first outlet passage and the motor drain line, the relief valve configured to allow fluid to be drained from the hydraulic motor to the tank via the first outlet passage disposed upstream of the outlet valve, the motor drain line and the second outlet passage.

11. The hydraulic system of claim 10 , wherein the relief valve is provided with a third biasing element that is configured to bias the relief valve into a flow-blocking position.

12. The hydraulic system of claim 11 , wherein a relief pressure setting associated with the third biasing element of the relief valve is more than an actuation pressure setting associated with the second biasing element of the outlet valve such that a pressure of fluid downstream of the hydraulic motor is configured to open the relief valve prior to opening the outlet valve when the solenoid-operated check valve is in the blocking position.

13. The hydraulic system of claim 12 further comprising a recirculation line fluidly coupled with the second inlet passage and the first outlet passage, the recirculation line having a unidirectional spring-loaded anti-cavitation check valve disposed therein, the anti-cavitation check valve being configured to selectively allow fluid to be recirculated from the first outlet passage downstream of the hydraulic motor to the second inlet passage upstream of the hydraulic motor.

14. The hydraulic system of claim 13 , wherein a pressure setting associated with the anti-cavitation valve is less than the relief pressure setting associated with the relief valve.

15. The hydraulic system of claim 13 , wherein a pressure setting associated with the anti-cavitation valve is less than a pressure setting of the second biasing element associated with the outlet valve.

16. The hydraulic system of claim 1 further comprising a bypass line configured to fluidly couple the first inlet passage with the second inlet passage, the bypass line including a second orifice disposed therein for permitting fluid with a reduced pressure and flow rate as compared to a pressure and flow rate of fluid in the first inlet passage.

17. The hydraulic system of claim 1 further comprising a controller communicably coupled with the solenoid-operated check valve, the controller configured to control an operation of the solenoid-operated check valve.

Assignees

• Caterpillar Inc

Inventors

• Mate Edward William
• Hudson Michael D

Classifications

• F04D25/04 Primary

  the pump being fluid-driven {(pumps driven by exhaust gases F02B37/00, F02B39/00; turbochargers F02C6/12)} · CPC title

• F15B2211/7142

  the output members being arranged in multiple groups · CPC title

• F15B2211/40507

  with constant throttles or orifices · CPC title

• F16H61/4035

  Control of circuit flow · CPC title

• F15B2211/7058

  Rotary output members · CPC title