Injection device

Patent metadata

Field	Value
Publication number	US-2024149513-A1
Application number	US-202218273223-A
Country	US
Kind code	A1
Filing date	Jan 20, 2022
Priority date	Jan 29, 2021
Publication date	May 9, 2024
Grant date	—

Abstract

An embodiment of the present invention provides an injection device including a screw that includes a plurality of outer circumferential protrusions, each of the plurality of outer circumferential protrusions being provided with an outer circumferential protrusion slope and a second outer circumferential protrusion slope. A bush of the injection device includes a plurality of inner circumferential protrusions, each of the plurality of inner circumferential protrusions being provided with an inner circumferential protrusion slope and a second inner circumferential protrusion slope. A rear end of each of the plurality of outer circumferential protrusions and a front end of each of the plurality of inner circumferential protrusions include no flat surface.

First claim

1 . An injection device comprising a screw disposed along a forward and rearward direction including a forward direction in which an injection resin is injected and a rearward direction opposite to the forward direction, and a bush configured to be spline-fitted to the screw, wherein
the screw includes a plurality of outer peripheral projections formed on an outer peripheral surface on a rear end side of the screw, the outer peripheral projections extending along the forward and rearward direction and being formed at intervals in a circumferential direction of the screw, each of the outer peripheral projections is formed with an outer peripheral projection inclined surface and a second outer peripheral projection inclined surface, the outer peripheral projection inclined surface being inclined in a manner so that an outer peripheral projection width along the circumferential direction of the screw becomes smaller toward a rear end of each of the outer peripheral projections, the second outer peripheral projection inclined surface being inclined in a manner so that an outer diameter of the screw becomes smaller toward the rear end of each of the outer peripheral projections, the bush includes a through hole extending in the forward and rearward direction, and a plurality of inner peripheral projections formed on an inner peripheral surface of the through hole, the inner peripheral projections extending in the forward and rearward direction and being formed at intervals in a circumferential direction of the through hole, each of the inner peripheral projections is formed with an inner peripheral projection inclined surface and a second inner peripheral projection inclined surface, the inner peripheral projection inclined surface being inclined in a manner so that an inner peripheral projection width along the circumferential direction of the through hole becomes smaller toward a front end of each of the inner peripheral projections, the second inner peripheral projection inclined surface being inclined in a manner so that an inner diameter of the bush becomes larger toward the front end of each of the inner peripheral projections, and a rear end of each of the outer peripheral projections and a front end of each of the inner peripheral projections include no flat surface.

2 . The injection device according to claim 1 , wherein
the outer peripheral projection inclined surface is formed on one of both side surfaces, in the circumferential direction of the screw, of a rear end side of each of the outer peripheral projections, and the inner peripheral projection inclined surface is formed on one of both side surfaces, in the circumferential direction of the through hole, of a front end side of each of the inner peripheral projections.

3 . The injection device according to claim 1 , wherein
the outer peripheral projection inclined surface is formed on each of both side surfaces, in the circumferential direction of the screw, of a rear end side of each of the outer peripheral projections, and the inner peripheral projection inclined surface is formed on each of both side surfaces, in the circumferential direction of the through hole, of a front end side of each of the inner peripheral projections.

4 . The injection device according to claim 1 ,
wherein the bush is provided with a protrusion protruding from a rear end surface of the bush, wherein the injection device further comprises: a bush fastening portion including a recess in which the protrusion is accommodated, the bush fastening portion being configured to fix the bush in a manner so that the protrusion is accommodated in the recess; and a cylinder in which the screw is accommodated, and wherein when a height of the second outer peripheral projection inclined surface is defined as Cs1, a height of the second inner peripheral projection inclined surface is defined as Cb1, a gap between the outer peripheral projections and the cylinder when the screw fitted to the bush is accommodated in the cylinder is defined as Ls1, and a gap between an outer periphery of the protrusion and an inner periphery of the recess when the bush is fixed to the bush fastening portion is defined as Lb1, a relationship of Cs1+Cb1>Ls1+Lb1 is satisfied.

5 . The injection device according to claim 1 , further comprising:
a linear motion motor configured to move the bush forward and rearward in the forward and rearward direction with respect to the screw; a detection unit configured to detect a linear motion torque of the linear motion motor; and a motor control unit configured to control the linear motion motor to move the bush forward from a position away from the screw and to stop the bush when the linear motion torque exceeds a linear motion torque threshold.

Assignees

• Fanuc Corp

Inventors

• Osawa Takuya
• Sekiguchi Shoutarou

Classifications

• B29C45/60

  Screws · CPC title

• B29C45/62

  Barrels or cylinders · CPC title

• B29C45/47

  using screws (B29C45/54 takes precedence) · CPC title

• B29C45/50

  Axially movable screw · CPC title

• B29C45/5008 Primary

  Drive means therefor · CPC title