Hydraulic circuit for opening and closing mould of injection moulding machine, and injection moulding machine system

1 . A hydraulic circuit for opening and closing a mould of an injection moulding machine, characterized by comprising an operating oil cylinder and a proportional valve; by means of adjusting the proportional valve to different operating states, the operating oil cylinder can be controlled to execute different actions, so as to control mould opening, mould closing and mould differential closing of the injection moulding machine;

wherein a first operating oil port and a second operating oil port of the proportional valve are respectively connected to a first cavity and a second cavity of the operating oil cylinder by means of a first connecting oil path and a second connecting oil path; an inlet oil port and a return oil port of the proportional valve are respectively connected to an inlet oil path and a return oil path;

when the proportional valve is in a first operating state, the first connecting oil path communicates with the inlet oil path by means of the proportional valve, the second connecting oil path communicates with the return oil path by means of the proportional valve, and the operating oil cylinder controls mould opening of the injection moulding machine;

when the proportional valve is in a second operating state, the first connecting oil path and the second connecting oil path communicate by means of the proportional valve, and the operating oil cylinder controls mould differential closing of the injection moulding machine;

when the proportional valve is in a third operating state, the first connecting oil path communicates with the return oil path by means of the proportional valve, the second connecting oil path communicates with the inlet oil path by means of the proportional valve, and the operating oil cylinder controls mould closing and pressing of the injection moulding machine;

wherein the proportional valve comprises a valve body, a spool and a driving apparatus;

wherein the valve body is provided with the first operating oil port, the second operating oil port, the inlet oil port and the return oil port;

wherein the spool is disposed inside the valve body in such a way as to be capable of relative movement, and is used for controlling communication and isolation between different oil ports;

wherein the driving apparatus is used for controlling the movement of the spool;

wherein the valve body is provided with:

a first oil channel, which communicates with the return oil port, so as to connect the return oil path;

a second oil channel, which communicates with the inlet oil port, so as to connect the inlet oil path;

a third oil channel, which communicates with the first operating oil port, so as to connect the first connecting oil path; and

a fourth oil channel, which communicates with the second operating oil port, so as to connect the second connecting oil path;

wherein a side wall of the spool is provided with a first recess, a second recess, a third recess, a fourth recess and a fifth recess;

wherein when the proportional valve is in the first operating state, the second oil channel communicates with the third oil channel by means of the third recess, and the fourth oil channel communicates with the first oil channel by means of the first recess;

wherein when the proportional valve is in the second operating state, the second oil channel communicates with the fourth oil channel by means of the second recess, and the second oil channel communicates with the third oil channel by means of the fifth recess;

wherein when the proportional valve is in the third operating state, the second oil channel communicates with the fourth oil channel by means of the second recess, and the third oil channel communicates with the first oil channel by means of the fourth recess;

wherein when the proportional valve is in a fourth operating state, the fourth oil channel, the second recess, the second oil channel, the fifth recess, the third oil channel, the fourth recess and the first oil channel communicate;

wherein the fifth recess and the third recess are both located between the second recess and the fourth recess;

wherein a partial region of the fifth recess and a partial region of the third recess are arranged in a staggered manner in a circumferential direction of the spool;

wherein another region of the fifth recess is closer to the fourth recess compared to the third recess; and

wherein another region of the third recess is closer to the second recess compared to the fifth recess.

2 . The hydraulic circuit for opening and closing a mould of an injection moulding machine according to claim 1 , wherein when the proportional valve is in the fourth operating state, the first operating oil port, the second operating oil port, the inlet oil port and the return oil port communicate with each other; and

the fourth operating state is a transition state between the second operating state and the third operating state; or the fourth operating state is an operating position of the proportional valve.

3 . The hydraulic circuit for opening and closing a mould of an injection moulding machine according to claim 1 , wherein projections of the first recess, the second recess, the third recess and the fourth recess on a central plane of the spool are arranged in sequence in an axial direction of the spool;

and/or one of each of the first recess, the second recess, the third recess and the fourth recess are provided, or a plurality thereof are respectively provided along the circumference of the spool.

4 . An injection moulding machine system, characterized by being provided with a hydraulic circuit for opening and closing a mould of an injection moulding machine,

wherein, the hydraulic circuit comprises an operating oil cylinder and a proportional valve; by means of adjusting the proportional valve to different operating states, the operating oil cylinder can be controlled to execute different actions, so as to control mould opening, mould closing and mould differential closing of the injection moulding machine;

wherein a first operating oil port and a second operating oil port of the proportional valve are respectively connected to a first cavity and a second cavity of the operating oil cylinder by means of a first connecting oil path and a second connecting oil path; an inlet oil port and a return oil port of the proportional valve are respectively connected to an inlet oil path and a return oil path;

when the proportional valve is in a first operating state, the first connecting oil path communicates with the inlet oil path by means of the proportional valve, the second connecting oil path communicates with the return oil path by means of the proportional valve, and the operating oil cylinder controls mould opening of the injection moulding machine;

when the proportional valve is in a second operating state, the first connecting oil path and the second connecting oil path communicate by means of the proportional valve, and the operating oil cylinder controls mould differential closing of the injection moulding machine;

when the proportional valve is in a third operating state, the first connecting oil path communicates with the return oil path by means of the proportional valve, the second connecting oil path communicates with the inlet oil path by means of the proportional valve, and the operating oil cylinder controls mould closing and pressing of the injection moulding machine;

wherein the proportional valve comprises a valve body, a spool and a driving apparatus;

wherein the valve body is provided with the first operating oil port, the second operating oil port, the inlet oil port and the return oil port;

wherein the spool is disposed inside the valve body in such a way as to be capable of relative movement, and is used for controlling communication and isolation between different oil ports;

wherein the driving apparatus is used for controlling the movement of the spool;

wherein the valve body is provided with:

a first oil channel, which communicates with the return oil port, so as to connect the return oil path;

a second oil channel, which communicates with the inlet oil port, so as to connect the inlet oil path;

a third oil channel, which communicates with the first operating oil port, so as to connect the first connecting oil path; and

a fourth oil channel, which communicates with the second operating oil port, so as to connect the second connecting oil path;

wherein a side wall of the spool is provided with a first recess, a second recess, a third recess, a fourth recess, and a fifth recess;

when the proportional valve is in the first operating state, the second oil channel communicates with the third oil channel by means of the third recess, and the fourth oil channel communicates with the first oil channel by means of the first recess;

when the proportional valve is in the second operating state, the second oil channel communicates with the fourth oil channel by means of the second recess, and the second oil channel communicates with the third oil channel by means of the fifth recess;

when the proportional valve is in the third operating state, the second oil channel communicates with the fourth oil channel by means of the second recess, and the third oil channel communicates with the first oil channel by means of the fourth recess;

wherein when the proportional valve is in a fourth operating state, the fourth oil channel, the second recess, the second oil channel, the fifth recess, the third oil channel, the fourth recess and the first oil channel communicate;

wherein the fifth recess and the third recess are both located between the second recess and the fourth recess;

a partial region of the fifth recess and a partial region of the third recess are arranged in a staggered manner in a circumferential direction of the spool;

another region of the fifth recess is closer to the fourth recess compared to the third recess; and

another region of the third recess is closer to the second recess compared to the fifth recess.

5 . The injection moulding machine system according to claim 4 , wherein when the proportional valve is in the fourth operating state, the first operating oil port, the second operating oil port, the inlet oil port and the return oil port communicate with each other; and

the fourth operating state is a transition state between the second operating state and the third operating state; or the fourth operating state is an operating position of the proportional valve.

6 . The injection moulding machine system according to claim 4 , wherein projections of the first recess, the second recess, the third recess and the fourth recess on a central plane of the spool are arranged in sequence in an axial direction of the spool;

one of each of the first recess, the second recess, the third recess and the fourth recess are provided, or a plurality thereof are respectively provided along the circumference of the spool.