Method to Detect Uncommanded Spool Valve Positioning and Stop Fluid Flow to Hydraulic Actuators

• US 20180094650A1
• Filed: 10/05/2016
• Published: 04/05/2018
• Est. Priority Date: 10/05/2016
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Lomax, David J., Callaway, Joshua D.
• Granted Patent: US 10,233,951 B2
• Time in Patent Office: Days
• CPC Class Codes: E02F 9/226 Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating
• CPC Class Codes: E02F 9/268 with failure correction follow-up actions
• CPC Class Codes: F15B 13/0871 Channels for fluid
• CPC Class Codes: F15B 19/005 Fault detection or monitoring
• CPC Class Codes: F15B 2211/3116 the pump port being open in the centre position, e.g. so-called open centre
• CPC Class Codes: F15B 2211/327 electrically or electronically
• CPC Class Codes: F15B 2211/329 actuated by fluid pressure
• CPC Class Codes: F15B 2211/355 Pilot pressure control
• CPC Class Codes: F15B 2211/45 Control of bleed-off flow, e.g. control of bypass flow to the return line
• CPC Class Codes: F15B 2211/6306 representing a pressure
• CPC Class Codes: F15B 2211/6313 the pressure being a load pressure
• CPC Class Codes: F15B 2211/6355 having valve means
• CPC Class Codes: F15B 2211/67 Methods for controlling pilot pressure
• CPC Class Codes: F15B 2211/857 Monitoring of fluid pressure systems
• CPC Class Codes: F15B 2211/8636 Circuit failure, e.g. valve or hose failure
• CPC Class Codes: F15B 2211/87 Detection of failures
• CPC Class Codes: F16K 31/36 in which fluid from the circuit is constantly supplied to the fluid motor
• CPC Class Codes: F16K 37/0083 by measuring valve parameters
• CPC Class Codes: G05D 7/005 characterised by the use of auxiliary non-electric power combined with the use of electric means
• CPC Class Codes: G05D 7/0635 by action on throttling means G05D7/0688, G05D7/0694 take precedence

Abstract

A system and method for detecting uncommanded positioning of at least one valve spool in a plurality of valve spools and for stopping fluid flow to a plurality of hydraulic actuators fluidly connected to the plurality of valve spools is disclosed. The method may comprise receiving a signal fluid pressure detected in a signal passageway, identifying whether at least one activation command is currently enabled, and stopping the flow of fluid to the plurality of hydraulic actuators if no activation command is enabled for any of the plurality of valve spools, and the signal fluid pressure when detected (1) upstream of the plurality of valve spools is greater than a first threshold or (2) downstream of the plurality of valve spools is less than a second threshold.

Claims

1. A method for detecting uncommanded positioning of at least one valve spool in a plurality of valve spools and for stopping a flow of fluid to a plurality of hydraulic actuators fluidly connected to the plurality of valve spools, the plurality of valve spools disposed downstream of a hydraulic pump and upstream of a reservoir, each valve spool having a neutral position and at least one active position, each valve spool configured to block flow of the fluid to at least one of the plurality of hydraulic actuators when the valve spool is in the neutral position and further configured to provide flow of the fluid to at least one of the hydraulic actuators when the valve spool is not in the neutral position, the plurality of valve spools fluidly connected to a plurality of pilot pressure reducing valves, each valve spool configured to maintain the active position when a pilot solenoid of one of the pilot pressure reducing valves is activated, the pilot solenoid activated when an activation command associated with a function of a machine controlled by the valve spool is enabled, the activation command received by a controller from a user interface, the method comprising:

receiving, by the controller, a signal fluid pressure detected in a signal passageway;

identifying, by the controller, whether at least one activation command is currently enabled; and

stopping, by the controller, the flow of the fluid to the plurality of hydraulic actuators if no activation command is enabled for any of the plurality of valve spools, and the signal fluid pressure when detected (1) upstream of the plurality of valve spools is greater than a first threshold or (2) downstream of the plurality of valve spools is less than a second threshold,

wherein, when each valve spool of the plurality of valve spools is in the neutral position, the signal passage extends through each valve spool of the plurality of valve spools, wherein further, when any valve spool of the plurality of valve spools is not in the neutral position or is in the active position, the signal passageway is blocked by the valve spool that is not in the neutral position or in the active position.

2. The method of claim 1, further including detecting the signal fluid pressure upstream of a first valve spool in the plurality of valve spools, the first valve spool positioned along the signal passageway to receive signal fluid before any other valve spools of the plurality of valve spools.

3. The method of claim 2, further including:

supplying, by the hydraulic pump, a fluid to the signal passageway; and

detecting the signal fluid pressure downstream of an orifice in the signal passageway and upstream of the first valve spool.

4. The method of claim 2, wherein the flow of the fluid to the plurality of hydraulic actuators is stopped by deactivating the pilot solenoid of each pilot pressure reducing valve or by deactivating a pilot shutoff solenoid that is operatively connected to each of the plurality of pilot pressure reducing valves.

5. The method of claim 2, wherein the flow of the fluid to the plurality of hydraulic actuators is stopped by shutting-off the hydraulic pump.

6. The method of claim 2, further including activating, by the controller, a lock valve fluidly connected to one of the hydraulic actuators if no activation command is enabled for any of the plurality of valve spools, and the signal fluid pressure when detected (1) upstream of the plurality of valves spools is greater than a first threshold or (2) downstream of the plurality of valve spools is less than a second threshold.

7. The method of claim 2, further including activating, by the controller, a swing brake operatively connected to one of the hydraulic actuators if no activation command is enabled for any of the plurality of valve spools, and the signal fluid pressure when detected (1) upstream of the plurality of valves spools is greater than a first threshold or (2) downstream of the plurality of valve spools is less than a second threshold.

8. The method of claim 1, further including detecting the signal fluid pressure downstream of the plurality of valve spools.

9. A system for detecting uncommanded positioning of a first valve spool of a plurality of valve spools and for stopping a flow of a fluid to a plurality of hydraulic actuators fluidly connected to the plurality of valve spools, the system comprising:

the plurality of hydraulic actuators disposed on a machine;

the plurality of valve spools disposed downstream of a hydraulic pump and upstream of a reservoir, the first valve spool of the plurality of valve spools having a neutral position and at least one active position, the first valve spool configured to block flow of the fluid to a first hydraulic actuator of the plurality of hydraulic actuators when in the neutral position and further configured to provide flow of the fluid to the first hydraulic actuator when not in the neutral position or when in the active position;

a plurality of pilot pressure reducing valves, each pilot pressure reducing valve fluidly connected to one of the plurality of valve spools, each pilot pressure reducing valve including a pilot solenoid configured to activate the pilot pressure reducing valve, each pilot pressure reducing valve configured to place one of the valve spools in the neutral position or in the active position;

a signal passageway that extends, when each valve spool of the plurality of valve spools is in the neutral position, through each valve spool of the plurality of valve spools to a reservoir, wherein when any valve spool of the plurality of valve spools is in the active position, the signal passageway is blocked by the valve spool in the active position;

a hydraulic pump configured to supply a fluid to the signal passageway and configured to supply the fluid to the plurality of hydraulic actuators via the plurality of valve spools;

a user interface configured to receive an activation command from a user, the activation command associated with a machine function controlled by one or more of the plurality of valve spools; and

a controller configured to;

receive a signal fluid pressure detected in a signal passageway;

identify whether at least one activation command is currently enabled; and

stop the flow of the fluid to the plurality of hydraulic actuators if no activation command is enabled for any of the plurality of valve spools, and the signal fluid pressure when detected (1) upstream of the plurality of valves spools is greater than a first threshold or (2) downstream of the plurality of valve spools is less than a second threshold.

10. The system of claim 9, further including a display, and in which the controller is further configured to display a warning on the display when no activation command is enabled, and the signal fluid pressure when detected (1) upstream of the plurality of valves spools is greater than a first threshold or (2) downstream of the plurality of valve spools is less than a second threshold.

11. The system of claim 9, in which the signal passageway includes an orifice,

wherein a first hydraulic actuator of the plurality of hydraulic actuators is a hydraulic motor and a second hydraulic actuator of the plurality of hydraulic actuators is a hydraulic cylinder.

12. The system of claim 9, in which the controller is further configured to activate a brake if no activation command is enabled for the first valve spool and the signal fluid pressure (1) when detected upstream of the plurality of signal valves is greater than a first threshold or (2) when detected downstream of the plurality of signal valves is less than a second threshold, the brake operatively connected to a first hydraulic actuator of the plurality of hydraulic actuators, the first hydraulic actuator a motor.

13. The system of claim 9, in which the system further includes a pilot shutoff solenoid operatively connected to the plurality of pilot pressure reducing valves, wherein the flow of the fluid to the plurality of hydraulic actuators is stopped by deactivating the pilot solenoid of each pilot pressure reducing valve or deactivating the pilot shutoff solenoid.

14. The system of claim 9, wherein the flow of the fluid to the plurality of hydraulic actuators is stopped by shutting-off the hydraulic pump.

15. The system of claim 14, wherein the signal fluid pressure was measured upstream of the plurality of valve spools.

16. A method for detecting uncommanded positioning of a first valve spool of a plurality of valve spools and for stopping flow of a fluid to a first hydraulic actuator that is fluidly connected to the first valve spool, the plurality of valve spools disposed downstream of a hydraulic pump and upstream of a reservoir, the first valve spool having a first position and a second position, the first valve spool configured to block flow of the fluid to the first hydraulic actuator when the first valve spool is in the first position and further configured to provide flow of the fluid to the first hydraulic actuator when the first valve spool is not in the first position or is in the second position, the first valve spool configured to maintain the second position when a pilot supply is activated, the pilot supply activated when an activation command for a function of a machine controlled by the first valve spool is enabled, the activation command received by a controller from a user interface, the method comprising:

receiving, by the controller, a signal fluid pressure detected in a signal passageway;

identifying, by the controller, whether the activation command is currently enabled; and

stopping, by the controller, the flow of the fluid to the first hydraulic actuator if no activation command is enabled for the first valve spool and the signal fluid pressure (1) when detected upstream of the plurality of signal valves is greater than a first threshold or (2) when detected downstream of the plurality of signal valves is less than a second threshold,

wherein, when the first valve spool is in the first position, the signal passage extends through the first valve spool,

wherein further when the first valve spool is in the second position or is not in the first position, the signal passageway is blocked by the first valve spool.

17. The method of claim 16 further including detecting the signal fluid pressure upstream of the first valve spool, the first valve spool positioned along the signal passageway to receive signal fluid before any other valve spools of the plurality of valve spools.

18. The method of claim 16, wherein the pilot supply includes a first pilot pressure reducing valve operatively connected to a first pilot solenoid, the pilot supply operatively connected to a pilot shutoff solenoid, wherein the flow of the fluid to the first hydraulic actuator is stopped by deactivating the first pilot solenoid or deactivating the pilot shutoff solenoid or shutting off the hydraulic pump.

19. The method of claim 16, further including activating, by the controller, a brake if no activation command is enabled for the first valve spool and the signal fluid pressure (1) when detected upstream of the plurality of signal valves is greater than a first threshold or (2) when detected downstream of the plurality of signal valves is less than a second threshold, the brake operatively connected to the first hydraulic actuator.

20. The method of claim 16, further including detecting the signal fluid pressure downstream of the plurality of valve spools.