US 12,186,955 B2
Injection device and molding machine
Toshiharu Fujioka, Isehara (JP); Kazuma Hayase, Yokohama (JP); Hiroshi Yokoyama, Ebina (JP); Makoto Tsuji, Yamato (JP); and Saburo Noda, Atsugi (JP)
Assigned to Shibaura Machine Co., Ltd., Tokyo (JP)
Appl. No. 17/436,477
Filed by Shibaura Machine Co., Ltd., Tokyo (JP)
PCT Filed Dec. 27, 2019, PCT No. PCT/JP2019/051422
§ 371(c)(1), (2) Date Sep. 3, 2021,
PCT Pub. No. WO2020/179209, PCT Pub. Date Sep. 10, 2020.
Claims priority of application No. 2019-038623 (JP), filed on Mar. 4, 2019.
Prior Publication US 2022/0168937 A1, Jun. 2, 2022
Int. Cl. B29C 45/67 (2006.01); B29C 45/53 (2006.01)
CPC B29C 45/531 (2013.01) [B29C 45/67 (2013.01)] 11 Claims
OG exemplary drawing
 
1. An injection device comprising:
an injection cylinder configured to drive a plunger ejecting a molding material into a mold;
a run-around circuit configured to cause a hydraulic fluid discharged from a rod-side chamber in the injection cylinder along with a forward movement of a piston in the injection cylinder to flow into a head-side chamber in the injection cylinder;
a tank configured to receive the hydraulic fluid discharged from the rod-side chamber along with the forward movement of the piston; and
a servo valve provided in the run-around circuit and connected to the tank, wherein the servo valve comprises one valve element, and is configured to:
achieve a first state where flow from the rod-side chamber to the head-side chamber is permitted while flow from the rod-side chamber to the tank is prohibited by the one valve element moving to a first position, and
achieve a second state where flow from the rod-side chamber to the head-side chamber is prohibited while flow from the rod-side chamber to the tank is permitted by the one valve element moving to a second position, and
control a flow rate of the hydraulic fluid discharged from the rod-side chamber in each of the first state and the second state by adjusting the position of the one valve element.