US 11,808,012 B2
Hydraulic system, mining machine and method of controlling hydraulic actuator
Reinhold Pogatschnigg, Katsch an der Mur (AT); and Christian Umundum, Spielberg (AT)
Assigned to Sandvik Mining and Construction G.m.b.H., Zeltweg (AT)
Appl. No. 17/637,550
Filed by SANDVIK MINING AND CONSTRUCTION G.M.B.H., Zeltweg (AT)
PCT Filed Aug. 27, 2019, PCT No. PCT/EP2019/072744
§ 371(c)(1), (2) Date Feb. 23, 2022,
PCT Pub. No. WO2021/037339, PCT Pub. Date Mar. 4, 2021.
Prior Publication US 2022/0290407 A1, Sep. 15, 2022
Int. Cl. E02F 9/22 (2006.01); F15B 11/044 (2006.01); F15B 11/04 (2006.01); E21D 9/10 (2006.01); F15B 11/10 (2006.01)
CPC E02F 9/226 (2013.01) [E02F 9/2296 (2013.01); E21D 9/1026 (2013.01); F15B 11/0413 (2013.01); F15B 11/0445 (2013.01); F15B 11/10 (2013.01); F15B 2211/20546 (2013.01); F15B 2211/5059 (2013.01); F15B 2211/50581 (2013.01); F15B 2211/6313 (2013.01); F15B 2211/7053 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A hydraulic system for a mining machine comprising:
a pump for producing hydraulic pressure and flow to the system;
a tank for storing and receiving hydraulic fluid;
a hydraulic actuator including a first working pressure space and a second working pressure space;
a first pressure conduit being in fluid connection with the first working pressure space and a second pressure conduit being in fluid connection with the second working pressure space;
a first counterbalance valve connected to the first pressure conduit and configured to restrict discharged fluid flow out of the first working pressure space and allowing free input flow into an opposite direction;
a second counterbalance valve connected to the second pressure conduit and configured to restrict discharged fluid flow out of the second working pressure space and allowing free input flow into an opposite direction;
a control valve arranged for controlling feeding and discharging of hydraulic fluid to and from the first and second working pressure spaces in order to control direction and speed of movement generated by the hydraulic actuator; and
a first solenoid valve arranged for controlling opening pressure of the first counterbalance valve and a second solenoid valve arranged for controlling opening pressure of the second counterbalance valve, whereby pressure of the hydraulic fluid discharging from the working pressure spaces of the hydraulic actuator is independently controllable.
 
13. A method of controlling a hydraulic actuator, the method comprising:
generating hydraulic pressure and flow by means of a hydraulic pump to a hydraulic system;
directing selectively hydraulic fluid flow from the pump to working pressure spaces of the hydraulic actuator and correspondingly discharging the hydraulic fluid from the working spaces to a tank by means of a control valve;
restricting the fluid flow discharged from the working pressure spaces by means of dedicated counterbalance valves; and
adjusting opening pressure of the counterbalance valves by means of separate solenoid valves and thereby providing the hydraulic actuator with adjustable force control being independently controllable relative to the control valve.