阅读说明：本技术 一种压射速度与压射力双闭环控制的油路结构及控制方式 (Oil circuit structure for double closed-loop control of injection speed and injection force and control mode ) 是由 郑培 胡宇 徐建华 于 2020-03-20 设计创作，主要内容包括：一种压射速度与压射力双闭环控制的油路结构及控制方式,很好的简化了油路结构,节约了成本,提高压射压力控制的稳定性；本发明技术方案为：包括第一蓄能器A1和第二蓄能器A2、压射油缸、油箱,所述的压射油缸包括增压无杆腔、增压有杆腔、压射无杆腔、压射有杆腔,第一蓄能器A1通过速度控制比例阀V16与压射无杆腔连接,第一蓄能器A1依次经压力补充阀V5、压力流量控制阀V12与压射有杆腔连接,第二蓄能器A2通过压力控制比例阀V14与增压无杆腔连接,增压有杆腔与油箱连接；本发明构思巧妙,提出了一种新的油路结构。(An oil path structure and a control mode for double closed-loop control of injection speed and injection force well simplify the oil path structure, save cost and improve the stability of injection pressure control; the technical scheme of the invention is as follows: the injection oil cylinder comprises a first energy accumulator A1, a second energy accumulator A2, an injection oil cylinder and an oil tank, wherein the injection oil cylinder comprises a pressurization rodless cavity, a pressurization rod cavity, an injection rodless cavity and an injection rod cavity, the first energy accumulator A1 is connected with the injection rodless cavity through a speed control proportional valve V16, the first energy accumulator A1 is sequentially connected with the injection rod cavity through a pressure supplementing valve V5 and a pressure flow control valve V12, the second energy accumulator A2 is connected with the pressurization rodless cavity through a pressure control proportional valve V14, and the pressurization rod cavity is connected with the oil tank; the invention has ingenious conception and provides a novel oil way structure.)

1. An oil circuit structure and a control mode for double closed-loop control of injection speed and injection force are characterized by comprising a first energy accumulator A1, a second energy accumulator A2, an injection oil cylinder 1 and an oil tank, wherein the injection oil cylinder 1 comprises a pressurization rodless cavity 11, a pressurization rod cavity 12, an injection rodless cavity 13 and an injection rod cavity 14, the first energy accumulator A1 is connected with the injection rodless cavity 13 through a speed control proportional valve V16, the first energy accumulator A1 is sequentially connected with the injection rod cavity 14 through a pressure supplement valve V5 and a pressure flow control valve V12, the second energy accumulator A2 is connected with the pressurization rodless cavity 11 through a pressure control proportional valve V14, and the pressurization rod cavity 12 is connected with the oil tank.

2. The oil circuit structure and the control mode for double closed-loop control of injection speed and injection force as defined in claim 1, wherein said first accumulator a1 is connected to the hydraulic system through a first energy storage valve V1 and a first energy storage pilot valve V2, and said second accumulator a2 is connected to the hydraulic system through a second energy storage valve V8 and a second energy storage pilot valve V7.

3. The structure and control mode of the oil path for double closed-loop control of the shot velocity and the shot force as defined in claim 1 is characterized in that the outlet part of the rod cavity of the shot cylinder 1 is provided with a displacement sensor R3.

4. The structure and control mode of the oil passage for double closed-loop control of shot velocity and shot force as defined in claim 1, wherein said inlet port of the shot rodless cavity 13 is connected to a first pressure sensor R2, and the inlet port of the shot rod cavity 14 is connected to a second pressure sensor R1.

5. The oil circuit structure and the control mode for double closed-loop control of the shot velocity and the shot force as defined in claim 1 are characterized in that the inlet part of the shot rodless cavity 13 is connected with a reset oil return valve V18 and a reset oil return pilot valve V17, and the other ends of the reset oil return valve V18 and the reset oil return pilot valve V17 are connected to an oil tank.

6. The structure and control mode of the oil passageway for double closed-loop control of shot velocity and shot force as defined in claim 1 characterized by said shot rod cavity 14 being connected to a hammer front/rear valve V6, said hammer front/rear valve V6 being connected to the shot rod cavity 14 on one side and to the shot rodless cavity 13 on the same side, the other side opposite to the shot rod cavity 14 being connected to the hydraulic system, and the other side opposite to the shot rodless cavity 13 being connected to the oil tank.

7. The structure and control mode of the oil path for double closed-loop control of shot velocity and shot force as defined in claim 6, characterized in that a post-hammer check valve V10 is connected between said shot rod cavity 14 and said pre-hammer/post-hammer valve V6.

8. The structure and control mode of the oil path for double closed-loop control of shot velocity and shot force as defined in claim 6, wherein a high-pressure isolating valve V19 is connected between said hammer front/hammer rear valve V6 and the shot rodless cavity 13.

9. The oil circuit structure and control mode of double closed-loop control of injection speed and injection force as defined in claim 2, characterized in that a first check valve V3 is connected between said first energy storage valve V1 and the first accumulator a1, and a second check valve V9 is connected between the second energy storage valve V8 and the second accumulator a 2.

10. The oil circuit structure and the control mode for double closed-loop control of the injection speed and the injection force as claimed in claim 1, wherein an oil return valve is connected between the first energy accumulator A1 and the second energy accumulator A2 and between the oil tanks, one end of a pressure flow control valve V12 is connected with the oil tank, and an overflow valve V13 is connected between the rod cavity 14 for injection and the oil tank.

Technical Field

The invention relates to the technical field of injection of die casting machines, in particular to an oil circuit structure for double closed-loop control of injection speed and injection force and a control mode.

Background

In the die-casting industry, different injection speeds and injection forces are often required for different working conditions, and the control and adjustment of the injection speeds and the injection forces in the current die-casting industry are generally divided into two different forms, the first of which is that: the common practice of small die-casting machines in the current industry is not to make special control on the precision of speed and pressure. For cost reasons: 1. the injection speed is controlled by manually adjusting an adjusting screw of a manual adjusting valve, so that the speed stability is poor, the adjusting amount cannot be automatically recorded every time, and the intellectualization of the die parameters cannot be realized; 2. the control of the ejection force is controlled by adjusting the energy storage pressure of the energy accumulator, the control mode needs to be matched with the adjustment of the energy storage pressure of the energy accumulator for control, the nitrogen is often charged or released in the process, the nitrogen is often used in an overpressure mode in the actual operation process, the ejection pressure exceeds the actually required injection force, the defects that the product is easy to generate flash and the like are caused, and meanwhile the service life of the die is also shortened. The automation degree of the scheme is low.

And the second method comprises the following steps: the speed and the pressurization are respectively and independently controlled, closed-loop control of the speed or/and the pressurization pressure can be realized, and the degree of automation is high. However, the existing control mode of the pressurization closed loop is to perform pressure control at the outlet of the pressurization cylinder to indirectly control the injection pressure; and the control oil circuit of the scheme has a complex structure and high manufacturing cost.

Therefore, a new oil path control structure is needed to solve the above problems.

Disclosure of Invention

Aiming at the technical problems to be solved, the invention provides the oil path structure and the control mode for [1] double closed-loop control of the injection pressure, so that the oil path structure is well simplified, the cost is saved, and the stability of injection pressure control is improved.

The technical scheme adopted by the invention for solving the technical problems is as follows: the injection oil cylinder 1 comprises a pressurization rodless cavity 11, a pressurization rod cavity 12, an injection rodless cavity 13 and an injection rod cavity 14, the first energy accumulator A1 is connected with the injection rodless cavity 13 through a speed control proportional valve V16, the first energy accumulator A1 is connected with the injection rod cavity 14 through a pressure supplementing valve V5 and a pressure flow control valve V12 in sequence, the second energy accumulator A2 is connected with the pressurization rodless cavity 11 through a pressure control proportional valve V14, and the pressurization rod cavity 12 is connected with the oil tank.

Preferably, the first energy accumulator a1 is connected with the hydraulic system through a first energy storage valve V1 and a first energy storage pilot valve V2, the second energy accumulator a2 is connected with the hydraulic system through a second energy storage valve V8 and a second energy storage pilot valve V7, the hydraulic system is connected from a point P, and the first energy accumulator a1 and the second energy accumulator a2 can be respectively stored with energy through the first energy storage valve V1 and the second energy storage valve V8.

Preferably, the outlet of the rod cavity of the injection cylinder 1 is provided with a displacement sensor R3, the displacement sensor R3 can feed back detected displacement data to the control system in real time, and the control system can perform closed-loop control on the speed control proportional valve V16 and the pressure flow control valve V12 through the displacement sensor R3, so as to realize accurate speed control.

Preferably, the inlet of the injection rodless cavity 13 is connected with a first pressure sensor R2, the inlet of the injection rod cavity 14 is connected with a second pressure sensor R1, the first pressure sensor R1 and the second pressure sensor R2 can immediately feed back the pressures detected at corresponding positions to the control system, and the final output pressure of the oil cylinder is controlled by the pressure values of the first pressure sensor R1 and the second pressure sensor R2, so as to achieve the purpose of closed-loop pressure control.

Preferably, the inlet part of the injection rodless cavity 13 is connected with a reset oil return valve V18 and a reset oil return pilot valve V17, and the other ends of the reset oil return valve V18 and the reset oil return pilot valve V17 are connected to an oil tank.

Preferably, the shot rod cavity 14 is connected with a hammer front/rear valve V6, the hammer front/rear valve V6 is a three-position four-way solenoid valve, one branch of the hammer front/rear valve V6 is connected to the shot rod cavity 14, the other branch of the hammer front/rear valve V6 is connected to the shot rodless cavity 13, the other side of the hammer front/rear valve opposite to the branch of the shot rod cavity 14 is connected with a hydraulic system, and the other side of the hammer front/rear valve opposite to the shot rodless cavity 13 is connected to an oil tank, as shown in fig. 1.

Preferably, a rear hammer check valve V10 is connected between the shot rod chamber 14 and the front/rear hammer valve V6, and the rear hammer check valve V10 prevents the reverse flow of the oil injected into the shot rod chamber 14.

Preferably, a high-pressure isolating valve V19 is connected between the hammer front/hammer rear valve V6 and the injection rodless cavity 13, the high-pressure isolating valve V19 is a one-way valve, and the flow direction is from the hammer front/hammer rear valve V6 to the injection rodless cavity 13.

Preferably, a first check valve V3 is connected between the first energy storage valve V1 and the first energy accumulator a1, the pressure supplement valve V5 is connected between the first energy accumulator a1 and the first energy accumulator a1, which is closer to the first check valve V3, and a second check valve V9 is connected between the second energy storage valve V8 and the second energy accumulator a 2.

Preferably, oil return valves are connected between the first accumulator a1 and the second accumulator a2 and the oil tank, one end of the pressure flow control valve V12 is connected with the oil tank, an overflow valve V13 is also connected between the injection rod cavity 14 and the oil tank, and the oil injected into the injection rod cavity can return to the oil tank through the overflow valve.

The invention has the following advantages:

firstly, on the premise of meeting the requirement of speed and pressure closed-loop control, the structure of an oil way is simplified, and the manufacturing cost is reduced;

secondly, the invention designs a new oil way structure, and adds an oil way control selection mode;

thirdly, the invention directly controls the final output injection force of the injection system, and the pressure control is more accurate.

Drawings

Fig. 1 is an overall oil circuit diagram of the shot system of the present invention.

In the figure, 1-injection oil cylinder, 11-pressurization rodless cavity, 12-pressurization rod cavity, 13-injection rodless cavity and 14-injection rod cavity.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

As can be seen from the attached figure 1, the oil path structure and the control mode for double closed-loop control of injection speed and injection force comprise a first energy accumulator A1, a second energy accumulator A2, an injection oil cylinder 1 and an oil tank, wherein the injection oil cylinder 1 comprises a pressurization rodless cavity 11, a pressurization rod cavity 12, an injection rodless cavity 13 and an injection rod cavity 14, the first energy accumulator A1 is connected with the injection rodless cavity 13 through a speed control proportional valve V16, the first energy accumulator A1 is sequentially connected with the injection rod cavity 14 through a pressure supplement valve V5 and a pressure flow control valve V12, the first energy accumulator A1, the speed control proportional valve V16, the pressure flow control valve V12 and the injection oil cylinder 1 form a speed control oil path together, the second energy accumulator A2 is connected with the pressurization rodless cavity 11 through a pressure control proportional valve V14, the pressurization rod cavity 12 is connected with the oil tank, the first energy accumulator A1, the second energy accumulator A6345, the pressure supplement valve V8236 and the pressure control valve V12, The injection cylinder 1 and the pressure control proportional valve V14 together constitute a pressure control oil path.

In order to conveniently store energy in the first energy accumulator A1 and the second energy accumulator A2, the first energy accumulator A1 is connected with a hydraulic system through a first energy storage valve V1 and a first energy storage pilot valve V2, the second energy accumulator A2 is connected with the hydraulic system through a second energy storage valve V8 and a second energy storage pilot valve V7, the hydraulic system is connected from a point P, and the first energy accumulator A1 and the second energy accumulator A2 can be stored with energy through the first energy storage valve V1 and the second energy storage valve V8 respectively.

In order to facilitate the real-time control of the injection speed, the outlet part of the rod cavity of the injection oil cylinder 1 is provided with a displacement sensor R3, the displacement sensor R3 can immediately feed detected displacement data back to a control system, and the speed control proportional valve V16 and the pressure flow control valve V12 can be controlled in a closed loop mode through the displacement sensor R3 and the control system, so that the accurate control of multiple sections of speeds is realized.

In order to control the injection pressure conveniently, the inlet of the injection rodless cavity 13 is connected with a first pressure sensor R2, the inlet of the injection rod cavity 14 is connected with a second pressure sensor R1, the first pressure sensor R1 and the second pressure sensor R2 can immediately feed the pressures detected at corresponding positions back to the control system, and the control system can perform closed-loop control on the pressure flow control valve V12 pressure control proportional valve V14 through the pressure values of the first pressure sensor R1 and the second pressure sensor R2 to accurately control the pressure of the injection rod cavity 14, directly control the final output injection force of the injection system, ensure that the final output injection force is a set target value in the system, and achieve the purpose of multi-stage pressure closed-loop control.

In order to facilitate resetting and circulating work of the injection rod, the inlet part of the injection rodless cavity 13 is connected with a resetting oil return valve V18 and a resetting oil return pilot valve V17, the other ends of the resetting oil return valve V18 and the resetting oil return pilot valve V17 are connected to the oil tank, and the retraction of the piston rod of the injection cylinder 1 can be controlled through different working states of the resetting oil return valve V18 and the resetting oil return pilot valve V17, so that the resetting action is realized.

In order to realize the reset of the injection rod, the injection rod cavity 14 is connected with a hammer front/hammer rear valve V6, the hammer front/hammer rear valve V6 is a three-position four-way solenoid valve, one branch of the hammer front/hammer rear valve V6 is connected to the injection rod cavity 14, the other branch of the hammer front/hammer rear valve V6 is connected to the injection rodless cavity 13, the other side, opposite to the branch of the injection rod cavity 14, is connected with a hydraulic system, and the other side, opposite to the injection rodless cavity 13, is connected to an oil tank, as shown in figure 1.

In order to control the working state of the before-hammer/after-hammer valve V6, an after-hammer check valve V10 is connected between the shot rod chamber 14 and the before-hammer/after-hammer valve V6, and the after-hammer check valve V10 prevents the oil shot into the rod chamber 14 from flowing backwards.

In order to better protect the hammer front/rear valve V6, a high-pressure isolation valve V19 is connected between the hammer front/rear valve V6 and the shot rodless cavity 13, the high-pressure isolation valve V19 is a one-way valve, the flow direction is from the hammer front/rear valve V6 to the shot rodless cavity 13, and the high-pressure isolation valve V19 can prevent oil liquid in the shot rodless cavity 13 from flowing backwards through the hammer front/rear valve V6, so as to prevent the hammer front/rear valve V6 from being damaged under high pressure.

In order to better protect the stored pressure of the first accumulator A1 and the second accumulator A2, a first check valve V3 is connected between the first energy storage valve V1 and the accumulator, a pressure supplementing valve V5 is connected between the first accumulator A1 and the first accumulator A1 and is closer to the first accumulator A1 relative to the first check valve V3, a second check valve V9 is connected between the second energy storage valve V8 and the second accumulator A2, and the first check valve V3 and the second check valve V9 can effectively improve the energy storage efficiency of the first accumulator A1 and the second accumulator A2 and avoid pressure leakage.

In order to ensure the oil return of the whole hydraulic system, oil return valves are connected between the first energy accumulator A1 and the second energy accumulator A2 and between the oil tank, one end of a pressure flow control valve V12 is connected with the oil tank, and an overflow valve V13 is connected between the injection rod cavity 14 and the oil tank.

The valve bodies are all electric control valves or logic valves, and the opening, closing, transposition or reversing of the valve bodies can be controlled by combining a control system with the self pressure of a hydraulic system in the using process;

the invention can be divided into seven different stages according to the working state when in specific use:

firstly, an energy storage state, wherein a hydraulic system is connected from a point P at the moment to provide a basic power source for an injection part, a first energy accumulator A1 and a second energy accumulator A2 are respectively controlled to store energy through a first energy storage valve V1 and a second energy storage valve V8, and after a set value is reached, related energy storage actions are automatically stopped; at this time, the first energy storage pilot valve V2 and the second energy storage pilot valve V7 control the opening and closing of the first energy storage valve V1 and the second energy storage valve V8 respectively, and the first check valve V3 and the second check valve V9 can avoid the backflow of oil liquid in the energy storage process.

Second, injecting a first stage: injecting at a slow speed; the slow ejection is synchronously controlled by a speed control proportional valve V16 and a pressure flow control valve V12, at the moment, a pilot valve of a reset oil return valve V18 is electrified, the reset oil return valve V18 is in a closed state, a pressure flow control valve V12 is adjusted to be in a speed control state, and analog quantities controlled by a speed control proportional valve V16 and a pressure flow control valve V12 are determined by the speed set by a system; the detection information is transmitted back to the control system through the displacement sensor R3, and the control signals of the speed control proportional valve V16 and the pressure flow control valve V12 are subjected to closed-loop control, so that the speed of the oil cylinder is controlled; under the control mode, the low-speed is stable, the starting is free from impact, and the repetition precision is high.

Thirdly, injecting a second stage: fast ejection; after the slow ejection in the first stage reaches the set position, the fast stage is entered, the working state of each valve body is kept consistent with that in the slow ejection stage, the analog quantity signals of the pressure flow control valve V12 and the speed control proportional valve V16 are controlled mainly according to the set speed of the system, and then the speed of the oil cylinder is controlled; under this control mode, the speed multistage is adjustable, and speed control is accurate, and repeatability is high.

Fourthly, third stage of injection: pressurizing and injecting; in the rapid injection process of the second stage of injection, after the set conditions of pressurized injection are met, the speed control proportional valve V16 starts to stop working, the speed control proportional valve V16 can be quickly closed, the reset oil return pilot valve V17 is continuously electrified at the moment, the reset oil return valve V18 is in a closed state, the pressure control proportional valve V14 is opened and starts to work in cooperation with the pressure flow control valve V12, the pressure flow control valve V12 is simultaneously switched to a pressure control state, and the pressure supplement valve V5 is opened as required at the moment so as to ensure the normal pressure control of the pressure flow control valve V12; in the working stage, a pressure value set by the control system is used as a target value, the pressure values detected by the first pressure sensor R1 and the second pressure sensor R2 are transmitted back to the control system in real time, the pressure flow control valve V12 is subjected to closed-loop control, the pressure difference detected by the first sensor and the second sensor is used for accurately controlling the pressure of the rod cavity of the oil cylinder, the injection force finally output by the injection system is directly controlled, and the finally output injection force is guaranteed to be the target value set in the system.

Fifthly, injecting a fourth stage: maintaining the pressure; after the pressurizing injection force is set to be a set value, the reset oil return pilot valve V17 is continuously electrified, the reset oil return valve V18 keeps a closed state, the pressure control proportional valve V14 keeps open, the pressure flow control valve V12 is continuously subjected to closed-loop control, and the control on the pressure of the rod cavity of the oil cylinder is kept, so that the stability of the injection force in the pressure maintaining process is ensured, the working state of the oil cylinder is basically consistent with the working state in the pressurizing injection stage, and the pressure is in a relatively stable state.

Sixthly, injecting the fifth stage: heel out; after the cooling time is over, the slow speed control of the first stage is repeated, the reset oil return pilot valve V17 is continuously powered on, the reset oil return valve V18 keeps a closed state, the speed control proportional valve V16 is synchronously controlled by matching with the pressure flow control valve V12, the pressure flow control valve V12 is switched to a speed control state at the moment, the analog quantity controlled by matching with the pressure flow control valve V12 through the speed control proportional valve V16 is determined by the speed set by the control system, and the oil cylinder speed is further controlled. Under the control mode, the speed control is stable, no impact exists, and the follow-up action is more reliable.

Seventhly, injecting a sixth stage: resetting; after the displacement sensor R3 detects that the piston reaches a following set value, the speed control proportional valve V16 is closed, the following action is closed, the pressure flow control valve V12 is switched to the middle position control again, the pre-hammer/post-hammer valve V6 is switched to the right position (namely the P is switched to the hammer return state of A), the reset oil return pilot valve V17 is de-energized, the reset oil return valve V18 is opened, the piston is retracted, and after the displacement sensor R3 detects that the piston returns to the original position, the actions are repeated for the next round of circulation.

According to the invention, the pressure flow control valve V12 is matched with the speed control proportional valve V16 and the pressure control proportional valve V14, different working states of the pressure flow control proportional valve are switched by a control system through different working stages, and double closed-loop control of pressure and speed is formed by combining real-time feedback of the displacement sensor R3 and the first pressure sensor R1 and the second pressure sensor R2; compared with the existing hydraulic structure which respectively controls the speed and the pressurization independently, the hydraulic structure is effectively simplified, and the cost is saved.

Compared with the existing pressurization closed-loop control structure, the pressure closed-loop real-time control method has the advantages that the collected data are fed back to the control system in real time through the mutual matching of the first pressure sensor R1 and the second pressure sensor R2, so that the pressure flow control valve V12 is controlled, the pressure closed-loop real-time control is carried out, the pressure can be controlled more accurately, the stability of the pressure is ensured, the oil cylinder is ensured to output the injection force truly, the injection quality of the whole work can be improved well, and the product quality is improved.

Each valve body can adopt but not limited to the types mentioned above, so long as the functions can be met, and the functions of each valve body can be realized by adopting a single valve body or a combined valve body of a plurality of valves, which belong to the protection scope of the application; furthermore, the control of the actuators in the present invention; can be applied to die casting machines, injection molding machines and the like; closed-loop control of the speed of the actuator; the method can be particularly applied to the control of oil cylinders, motors and the like; the pressure closed-loop control of the actuating element can be particularly applied to the control of the oil cylinder.