US 9,810,244 B2
Flow control valve for construction machinery
Jin-Wook Kim, Changwon-si (KR)
Assigned to VOLVO CONSTRUCTION EQUIPMENT AB, (SE)
Appl. No. 14/411,717
Filed by Jin-Wook Kim, Changwon-si (KR)
PCT Filed Jul. 19, 2012, PCT No. PCT/KR2012/005771
§ 371(c)(1), (2), (4) Date Dec. 29, 2014,
PCT Pub. No. WO2014/014146, PCT Pub. Date Jan. 23, 2014.
Prior Publication US 2015/0159678 A1, Jun. 11, 2015
Int. Cl. F16D 31/02 (2006.01); F15B 11/024 (2006.01); E02F 9/22 (2006.01); F15B 13/02 (2006.01); F16K 11/07 (2006.01); F15B 11/04 (2006.01); F15B 11/042 (2006.01); F15B 13/04 (2006.01)
CPC F15B 11/024 (2013.01) [E02F 9/2267 (2013.01); F15B 11/0406 (2013.01); F15B 11/0426 (2013.01); F15B 13/021 (2013.01); F15B 13/0403 (2013.01); F16K 11/07 (2013.01); F15B 2211/205 (2013.01); F15B 2211/20576 (2013.01); F15B 2211/30565 (2013.01); F15B 2211/3133 (2013.01); F15B 2211/31582 (2013.01); F15B 2211/355 (2013.01); Y10T 137/87193 (2015.04)] 3 Claims
OG exemplary drawing
 
1. A flow rate control valve for a construction machine, which is configured to control the supply of a hydraulic fluid to a hydraulic actuator from first and second hydraulic pumps, the control valve comprising:
a first boom valve block connected to the first hydraulic pump;
a second boom valve block connected to the second hydraulic pump;
a first boom spool slidably coupled to the first boom valve block and configured to be shifted by the supply of a pilot signal pressure to control the supply of the hydraulic fluid to a boom cylinder from the first hydraulic pump so as to perform a boom-up or boom-down operation;
a second boom spool slidably coupled to the boom second valve block and configured to be shifted by the supply of the pilot signal pressure to control the supply of the hydraulic fluid to the boom cylinder from the second hydraulic pump so as to perform the boom-up or boom-down operation;
a boom-up flow rate adjustment means configured to supply the hydraulic fluid from the first and second hydraulic pumps to a large chamber of the boom cylinder via the first and second boom spools and allow a part of the hydraulic fluid from the second hydraulic pump to join the hydraulic fluid being supplied from the first hydraulic pump to the large chamber of the boom cylinder via the second boom spool through the shift of the first boom spool when the first and second boom spools are shifted to perform the boom-up operation; and
a boom-down flow rate adjustment means configured to allow a part of the hydraulic fluid being fed back from the large chamber of the boom cylinder to be returned to the hydraulic tank via the first and second boom spools and allow a part of the hydraulic fluid being fed back from the large chamber of the boom cylinder to join the hydraulic fluid on a small chamber side of the boom cylinder as a regenerative hydraulic fluid when the first and second boom spools are shifted to perform the boom-down operation;
wherein the boom-up flow rate adjustment means allows the part of the hydraulic fluid from the second hydraulic pump to join the hydraulic fluid at the outside via the shifted second boom spool so as to be supplied to the large chamber of the boom cylinder, and allows the part of the hydraulic fluid from the second hydraulic pump to be supplied through a confluence line that fluidically communicates with a cylinder passage in the first boom valve block via a poppet installed in the second boom valve block to cause the part of the hydraulic fluid to join the hydraulic fluid that is supplied from the first hydraulic pump to the large chamber of the boom cylinder via the first boom spool; and
wherein the boom-down flow rate adjustment means comprises:
a regenerating poppet mounted on one side of the inside of the first boom spool to allow the part of the hydraulic fluid being fed back from the large changer of the boom cylinder to join the hydraulic fluid being supplied to the small chamber of the boom cylinder as the regenerative hydraulic fluid when the first boom spool is shifted;
a boom booster poppet mounted on the first boom valve block in such a manner as to be positioned in a path along which the hydraulic fluid being fed back from the larger chamber of the boom cylinder returns to the hydraulic tank via the first boom spool during the boom-down operation, and configured to generate a back pressure to control the boom drop speed to prevent a boom from dropping down abruptly by its own weight during the boom-down operation; and
a boom booster poppet mounted on the second boom valve block in such a manner as to be positioned in a path along which the hydraulic fluid being fed back from the larger chamber of the boom cylinder returns to the hydraulic tank via the second boom spool during the boom-down operation, and configured to generate a back pressure to control the boom drop speed to prevent a boom from dropping down abruptly by its own weight during the boom-down operation.