Injection apparatus and molding machine

Patent metadata

Field	Value
Publication number	US-10449604-B2
Application number	US-201815945273-A
Country	US
Kind code	B2
Filing date	Apr 4, 2018
Priority date	Apr 6, 2017
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

In an injection cylinder which can be connected with a plunger, the internal portion of the cylinder part is partitioned by a piston into a rod-side chamber on the side of the piston rod and a head-side chamber on the opposite side. An accumulator can supply a hydraulic fluid to the head-side chamber. A head-use pressure sensor can detect a pressure of the head-side chamber. A flow control valve can control a flow rate of the hydraulic fluid discharged from the rod-side chamber. A control device includes an OP control part which starts open control driving the flow control valve to the opening direction after the start of supply of the hydraulic fluid from the accumulator to the head-side chamber conditional on the detection pressure of the head-use pressure sensor rising up to the predetermined set value.

First claim

The invention claimed is:

1. An injection apparatus comprising
an injection cylinder which includes:
a piston rod connectable to a plunger capable of sliding in a sleeve communicated with an interior of a die,
a piston fixed to the piston rod, and
a cylinder part slidably accommodating the piston,
in which an internal portion of the cylinder part is partitioned by the piston into a rod-side chamber on a piston rod side and a head-side chamber on an opposite side;

an input device configured to accept an operation by a user;
a liquid pressure source which is configured to supply a hydraulic fluid to the head-side chamber;
a head-use pressure sensor which is configured to detect a pressure of the head-side chamber;
a flow control valve which is configured to control a flow rate of the hydraulic fluid discharged from the rod-side chamber, wherein the flow control valve is configured to position a valve element at a position in accordance with a command value of an input control command, keeps a port closed while the valve element moves at a time when the valve element is located at a predetermined overlapping section at which a part of the valve element overlaps the port, and makes the port begin opening by the valve element passing through the overlapping section; and
a control device which includes:
an open control part configured to start open control driving the flow control valve to an opening direction after a start of supply of the hydraulic fluid from the liquid pressure source to the head-side chamber conditional on a detection pressure of the head-use pressure sensor rising up to a predetermined set value,
a storage part configured to hold characteristic information linking a command value of the input control command to the flow control valve and a speed of the plunger including movement of the plunger caused by clearance flow while the valve element is located in the overlapping section,
a target speed setting part configured to set a target speed of the plunger based on an operation accepted by the input device, and
a command value setting part configured to set a command value of a control command output by the open control part in the open control by specifying the command value of the input control command to the flow control valve corresponding to the target speed set by the target speed setting part based on the characteristic information.

2. The injection apparatus according to claim 1 , further comprising:
an accumulator as the liquid pressure source; and
an accumulator-use pressure sensor configured to detect the pressure of the accumulator, wherein:
the control device further comprises a correction part configured to make the command value of the control command output by the open control part change between cycles so that an opening of the flow control valve in the open control becomes larger as the detection pressure of the accumulator-use pressure sensor at a predetermined point of time before a start of the open control is lower.

3. The injection apparatus according to claim 2 , wherein the correction part is configured to make the command value of the control command output by the open control part change between cycles by correcting the characteristic information referred to by the command value setting part so that the speed of the plunger linked with the command value of the control command becomes lower as the detection pressure of the accumulator-use pressure sensor at the predetermined point of time is lower.

4. The injection apparatus according to claim 1 , further comprising a position sensor capable of detecting a position of the plunger, wherein the control device further comprises an information updating part configured to update the characteristic information based on a command value of the control command output in the open control and on a speed detected by the position sensor in the open control.

5. The injection apparatus according to claim 4 , wherein:
the control device further comprises a quality judgment part configured to judge whether a difference between the position of the plunger calculated based on the target speed set by the target speed setting part and the position of the plunger detected by the position sensor at a point of an end of the open control is within a predetermined permissible range, and
the information updating part is configured to update the characteristic information based on the command value and speed in the open control only during a time of judgment by the quality judgment part that a difference is in a permissible range.

6. The injection apparatus according to claim 1 , further comprising:
a position sensor configured to detect a position of the plunger, and
a display device configured to display an image, wherein
the control device further comprises:
a quality judgment part configured to judge whether a difference between a position of the plunger calculated based on the target speed set by the target speed setting part and the position of the plunger detected by the position sensor at a point of an end of the open control exceeds a predetermined threshold value and
a display control part configured to make the display device display a predetermined alert image in response to judging that the difference exceeds the threshold value.

7. The injection apparatus according to claim 1 , further comprising a position sensor capable of detecting a position of the plunger, wherein the control device further comprises a feedback control part configured to perform, continuing from the open control, feedback control of the flow control valve based on a detection value of the position sensor so that the target speed set by the target speed setting part is realized.

8. A molding machine comprising the injection apparatus according to claim 1 .

9. An injection apparatus comprising
an injection cylinder which includes:
a piston rod connectable to a plunger capable of sliding in a sleeve communicated with an interior of a die,
a piston fixed to the piston rod, and
a cylinder part slidably accommodating the piston,
in which an internal portion of the cylinder part is partitioned by a piston to a rod-side chamber on a piston rod side and a head-side chamber on an opposite side;

an input device configured to accept an operation by a user;
a liquid pressure source which is configured to supply a hydraulic fluid to the head-side chamber;
a rod-use pressure sensor which is configured to detect a pressure of the rod-side chamber;
a flow control valve which is configured to control a flow rate of the hydraulic fluid discharged from the rod-side chamber, wherein the flow control valve is configured to position a valve element at a position in accordance with a command value of an input control command, keep a port closed while the valve element moves at a time when the valve element is located at a predetermined overlapping section at which a part of the valve element overlaps the port, and make the port begin opening by the valve element passing through the overlapping section; and
a control device which includes:
an open control part configured to start open control driving the flow control valve to an opening direction after a start of supply of the hydraulic fluid from the liquid pressure source to the head-side chamber conditional on a detection pressure of the rod-use pressure sensor rising up to a predetermined set value,
a storage part configured to hold characteristic information linking a command value of the input control command to the flow control valve and a speed of the plunger including movement of the plunger caused by clearance flow while the valve element is located in the overlapping section,
a target speed setting part confi

Assignees

• Toshiba Machine Co Ltd

Inventors

• Yokoyama Hiroshi

Classifications

• B29C2945/76498

  Pressure · CPC title

• B29C45/77 Primary

  of velocity or pressure of moulding material · CPC title

• B29C2945/76545

  Flow rate · CPC title

• B22D2/00

  Arrangement of indicating or measuring devices, e.g. for temperature or viscosity of the fused mass · CPC title

• B22D17/203

  Injection pistons (B22D17/2053 takes precedence; for plastics B29C45/53) · CPC title