Emergency steering pump system for a machine

Patent metadata

Field	Value
Publication number	US-10259493-B2
Application number	US-201615373558-A
Country	US
Kind code	B2
Filing date	Dec 9, 2016
Priority date	Dec 9, 2016
Publication date	Apr 16, 2019
Grant date	Apr 16, 2019

Abstract

An emergency steering pump system for a primary pump providing a standby pressure via a primary output line includes a load sense line that is configured to branch-off from the primary output line. The load sense line has a first orifice disposed therein. A secondary pump is included for providing a margin pressure via a secondary output line that is coupled to the primary output line at a point downstream of the load sense line. A communication line is coupled to the primary output line at a point upstream of the load sense line. The communication line has a pressure control mechanism disposed therein. An output of the pressure control mechanism is coupled with an unloader valve of the secondary pump such that the pressure control mechanism is configured to bring about the margin pressure from the secondary pump.

First claim

What is claimed is:

1. An emergency steering pump system for a primary pump providing a standby pressure via a primary output line, the emergency steering pump system comprising:
a load sense line configured to branch-off from a point located partway along a length of the primary output line,
the load sense line having a first orifice disposed therein;

a secondary pump for providing a margin pressure,
the secondary pump having a secondary output line coupled to the primary output line at a point downstream of the load sense line;

a communication line coupled to the primary output line at a point upstream of the load sense line,
the communication line having a pressure control mechanism disposed therein,
wherein an output of the pressure control mechanism is coupled with an unloader valve of the secondary pump such that the pressure control mechanism is configured to bring about the margin pressure from the secondary pump; and

a spring-loaded check valve disposed in the load sense line and located at a point in the load sense line downstream of the first orifice.

2. The emergency steering pump system of claim 1 , wherein the pressure control mechanism includes a resolver.

3. The emergency steering pump system of claim 1 , further comprising a variable spring-loaded relief valve disposed between a point upstream of the primary pump and the output of the pressure control mechanism.

4. The emergency steering pump system of claim 1 , further comprising a first spring-loaded check valve disposed in the primary output line and located at a point on the primary output line downstream of the load sense line,
the first spring-loaded check valve being configured to selectively allow a unidirectional flow of fluid from the primary pump via the primary output line.

5. The emergency steering pump system of claim 4 , further comprising:
a first pressure sensor disposed in the primary output line and located at a point in the primary output line upstream of the load sense line and the first spring-loaded check valve,
the first pressure sensor being configured to measure the standby pressure being output by the primary pump;

a second pressure sensor disposed in the primary output line and located at a point in the primary output line downstream of the secondary output line,
the second pressure sensor being configured to measure at least one of the primary pump pressure and the secondary pump pressure; and

a controller disposed in communication with each of the first pressure sensor and the second pressure sensor,
the controller, upon start-up, being configured to:
engage the secondary pump for a pre-defined duration,
monitor a cumulative pressure of the standby pressure and the margin pressure, and
determine readiness of the secondary pump based on the cumulative pressure as compared to a pre-defined threshold,
wherein the controller designates the readiness of the secondary pump as successful if the cumulative pressure substantially reaches the pre-defined threshold prior to an expiration of the pre-defined duration.

6. The emergency steering pump system of claim 1 , further comprising a second spring-loaded check valve disposed in the secondary output line,
the second spring-loaded check valve being configured to selectively allow a unidirectional flow of fluid from the secondary pump via the secondary output line.

7. The emergency steering pump system of claim 1 , where the spring-loaded check valve is configured to selectively allow a unidirectional flow of fluid from the primary output line to the communication line via the load sense line.

8. An emergency steering pump system for a primary pump providing a standby pressure via a primary output line, the emergency steering pump system comprising:
a load sense line configured to branch-off from a point located partway along a length of the primary output line,
the load sense line having a first orifice disposed therein;

a secondary pump for providing a margin pressure,
the secondary pump having a secondary output line coupled to the primary output line at a point upstream of the load sense line;
a communication line coupled to the primary output line at a point upstream of the load sense line,
the communication line having a pressure control mechanism disposed therein such that an output of the pressure control mechanism is coupled with an unloader valve of the secondary pump,
wherein the first orifice and the pressure control mechanism are configured to co-operatively bring about the margin pressure from the secondary pump; and

a first pressure sensor disposed in the primary output line,
the first pressure sensor being configured to measure the standby pressure; and

a second pressure sensor disposed in the primary output line and located at a point in the primary output line downstream of the load sense line.

9. The emergency steering pump system of claim 8 , wherein the pressure control mechanism includes a resolver.

10. The emergency steering pump system of claim 8 , further comprising a variable spring-loaded relief valve disposed between a point upstream of the primary pump and the output of the pressure control mechanism.

11. The emergency steering pump system of claim 8 , further comprising a first spring-loaded check valve disposed in the primary output line and located at a point on the primary output line upstream of the secondary output line,
the first spring-loaded check valve being configured to selectively allow a unidirectional flow of fluid from the primary pump via the primary output line.

12. The emergency steering pump system of claim 11 , further comprising a second spring-loaded check valve disposed in the secondary output line,
the second spring-loaded check valve being configured to selectively allow a unidirectional flow of fluid from the secondary pump via the secondary output line.

13. The emergency steering pump system of claim 8 , further comprising:
a controller disposed in communication with each of the first pressure sensor and the second pressure sensor,
the controller, upon start-up, being configured to:
engage the secondary pump for a pre-defined duration,
monitor a cumulative pressure of the standby pressure and the margin pressure, and
determine readiness of the secondary pump based on the cumulative pressure as compared to a pre-defined threshold,
wherein the controller designates the readiness of the secondary pump as successful if the cumulative pressure substantially reaches the pre-defined threshold prior to an expiration of the pre-defined duration.

14. An emergency steering pump system for a primary pump providing a standby pressure via a primary output line, the emergency steering pump system comprising:
a load sense line configured to branch-off from a point located partway along a length of the primary output line,
the load sense line having a first orifice disposed therein;

a secondary pump for providing a margin pressure, the secondary pump having a secondary output line coupled to the primary output line at a point downstream of the load sense line;
a communication line coupled to the load sense line,
the communication line having a pressure control mechanism disposed therein such that an input of the pressure control mechanism is fluidly coupled to the secondary output line at a point located downstream of an unloader valve associated with the secondary pump, and
the input of the pressure control mechanism being provided with a second orifice such that the second orifice facilitates the pressure control mechanism to co-operate with the first and second orifices for bringing

Assignees

• Caterpillar Inc

Inventors

• Mate Edward William
• Mork David
• Johnson Steven Edward

Classifications

• B62D5/065

  characterised by specially adapted means for varying pressurised fluid supply based on need, e.g. on-demand, variable assist · CPC title

• B62D5/30 Primary

  Safety devices, e.g. alternate emergency power supply or transmission means to ensure steering upon failure of the primary steering means · CPC title