MACHINE HAVING HYDRAULICALLY ACTUATED IMPLEMENT SYSTEM WITH COMBINED RIDE CONTROL AND DOWNFORCE CONTROL SYSTEM

• US 20140178164A1
• Filed: 12/20/2012
• Published: 06/26/2014
• Est. Priority Date: 12/20/2012
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Peterson, Jeremy T., Kuehn, Jeffrey L., Knussman, Michael L., Lomax, David J.
• Granted Patent: US 9,068,323 B2
• Time in Patent Office: Days
• US Class Current: 414/685
• CPC Class Codes: E02F 3/432 for keeping the bucket in a predetermined position or attitude
• CPC Class Codes: E02F 9/0841 Articulated frame, i.e. having at least one pivot point between two travelling gear units tractor-trailer combinations B62D53/00
• CPC Class Codes: E02F 9/2207 for reducing or compensating oscillations
• CPC Class Codes: E02F 9/2217 with energy recovery arrangements, e.g. using accumulators, flywheels
• CPC Class Codes: F15B 1/021 used for damping
• CPC Class Codes: F15B 1/033 with electrical control means
• CPC Class Codes: F15B 21/082 with different modes
• CPC Class Codes: F15B 2211/625 Accumulators
• CPC Class Codes: F15B 2211/6346 representing a state of input means, e.g. joystick position
• CPC Class Codes: F15B 2211/6653 Pressure control
• CPC Class Codes: F15B 2211/6658 Control using different modes, e.g. four-quadrant-operation, working mode and transportation mode
• CPC Class Codes: F15B 2211/7128 the chambers being connected in parallel
• CPC Class Codes: F15B 2211/85 Control during special operating conditions
• CPC Class Codes: F15B 2211/8606 the abnormal condition being a shock
• CPC Class Codes: F15B 2211/8616 the abnormal condition being noise or vibration
• CPC Class Codes: Y10T 137/85986 Pumped fluid control

Abstract

A machine is disclosed. The machine can include a frame and ground engaging propulsion elements coupled with the frame. A hydraulically actuated implement system can be coupled with the frame, and can include a linkage configured to couple with an implement, a hydraulic actuator coupled with the linkage and the frame, and a ride control and downforce control circuit configured to implement a ride control mode and a downforce control mode. The ride control mode can be configured to maintain a pressure of hydraulic fluid in the hydraulic actuator at a ride control pressure, and the downforce control mode can be configured to maintain the pressure of hydraulic fluid in the hydraulic actuator at a downforce control pressure to oppose the weight of the linkage and the implement such that the implement engages a substrate with a predetermined down force pressure which is proportionate to the downforce control pressure.

Claims

1. A machine comprising:

a frame;

ground engaging propulsion elements coupled with the frame;

a hydraulically actuated implement system coupled with the frame, and including a linkage configured to couple with an implement, a hydraulic actuator coupled with the linkage and the frame, and a combined ride control and downforce control circuit configured to implement a ride control mode and a downforce control mode;

the ride control mode configured to maintain a pressure of hydraulic fluid in the hydraulic actuator at a ride control pressure; and

the downforce control mode configured to maintain the pressure of hydraulic fluid in the hydraulic actuator at a downforce control pressure to oppose the weight of the linkage and the implement such that the implement is controllably rested upon and engages a substrate positioned under the implement with a predetermined down force pressure which is proportionate to the downforce control pressure.

2. The machine of claim 1 wherein the combined ride control and downforce control circuit includes a switching valve, the switching valve configured to actuate the ride control and downforce control circuit between the ride control mode and downforce control mode.

3. The machine of claim 2 wherein the combined ride control and downforce control circuit includes a pressure reducing valve, the pressure reducing valve configured to provide an outlet flow of pressurized fluid at the downforce control pressure based upon a pressure setting of the pressure reducing valve.

4. The machine of claim 3 wherein the combined ride control and downforce control circuit is connected in fluid communication between a hydraulic pump and the hydraulic actuator.

5. The machine of claim 4 wherein the switching valve is connected in fluid communication between the pressure reducing valve and the hydraulic actuator, and the pressure reducing valve is connected in fluid communication between the hydraulic pump and the switching valve.

6. The machine of claim 5 wherein a downforce control position of the switching valve is configured to actuate the combined ride control and downforce control circuit to the downforce control mode and adjust the pressure of hydraulic fluid in the hydraulic actuator to the downforce control pressure of the pressure reducing valve.

7. The machine of claim 6 wherein a ride control position of the switching valve is configured to actuate the combined ride control and downforce control circuit to the ride control mode and adjust the pressure of hydraulic fluid in the hydraulic actuator to the ride control pressure provided by a feedback pressure from the hydraulic actuator.

8. The machine of claim 7 wherein the switching valve and the pressure reducing valve are each electronically actuated by and controllably coupled with an electronic control unit.

9. The machine of claim 8 wherein the electronic control unit is configured to receive an implement down force control activation command, and responsively actuate the switching valve to the downforce control position and adjust the pressure setting of the pressure reducing valve to the downforce control pressure.

10. A hydraulically actuated implement system comprising:

a combined ride control and downforce control circuit connected in fluid communication between a hydraulic pump and a hydraulic actuator;

the combined ride control and downforce control circuit including a switching valve and a pressure reducing valve;

the switching valve connected in fluid communication between the pressure reducing valve and the hydraulic actuator; and

the pressure reducing valve connected in fluid communication between the hydraulic pump and the switching valve.

11. The hydraulically actuated implement system of claim 10 wherein the pressure reducing valve includes a pilot-operated spool which is configured to provide an outlet flow of pressurized fluid which is limited to a pressure setting of the pressure reducing valve.

12. The machine of claim 11 wherein the downforce control pressure is substantially equivalent to the pressure setting of the pressure reducing valve.

13. The hydraulically actuated implement system of claim 12 additionally comprising an accumulator positioned between the hydraulic pump and the lift actuator, the accumulator fluidly connected to supply pressurized fluid to the lift actuator.

14. The hydraulically actuated implement system of claim 13 wherein the switching valve is fluidly connected between the lift actuator, the pressure reducing valve, and the accumulator.

15. The hydraulically actuated implement system of claim 14 wherein a downforce control position of the switching valve directs pressurized fluid from the pressure reducing valve as an accumulator control pressure such that the pressurized fluid supplied by the accumulator to the lift actuator is adjusted to the downforce control pressure supplied by the pressure reducing valve.

16. A control system for a hydraulically actuated implement system in a machine comprising:

an electronic control unit in electronic communication with a combined ride control and downforce control circuit, the combined ride control and downforce control circuit connected in fluid communication between a hydraulic pump and a hydraulic actuator;

the electronic control unit configured to receive a ride control activation command, and responsively actuate the combined ride control and downforce control circuit to a ride control mode, the ride control mode maintaining a pressure of hydraulic fluid in the hydraulic actuator at a ride control pressure;

the electronic control unit configured to receive a downforce control activation command, and responsively actuate the combined ride control and downforce control circuit to a downforce control mode, the downforce control mode maintaining the pressure of hydraulic fluid in the hydraulic actuator at a downforce control pressure to oppose the weight of a linkage and an implement such that the implement engages a substrate positioned under the implement with a down force pressure which is proportionate to the downforce control pressure.

17. The control system of claim 16 wherein the electronic control unit is configured to receive one or more downforce control commands, and responsively adjust the downforce control pressure of the hydraulic fluid in the hydraulic actuator to a pressure specified by each of the one or more implement downforce control commands.

18. The control system of claim 17 wherein the downforce control pressure is determined by the control system based upon implement type.

19. The control system of claim 17 wherein the downforce control pressure is a user-specified downforce control pressure electrically transmitted to the electronic control unit from an input device.

20. The control system of claim 18 wherein the combined ride control and downforce control circuit includes a pressure reducing valve, and wherein the electronic control unit is configured to adjust a downforce control pressure setting of the pressure reducing valve to a pressure specified by one of the one or more implement downforce control commands.