A centering hydraulic system for an aluminum ingot tipping apparatus

Abstract

The present application relates to a kind of centering hydraulic system of aluminium ingot tipping equipment, belong to hydraulic control equipment field.It includes four executing agencies of synchronous action, four oil cylinders of synchronous action and four groups of centering valve group, each executing agency is driven by an oil cylinder, each oil cylinder is controlled by a group of centering valve group;Centering valve group includes proportional reversing valve with valve core position feedback, pressure compensator, balance valve and pressure switch;The oil inlet and oil outlet of proportional reversing valve with valve core position feedback side are communicated with oil tank by pipeline respectively, two oil outlets of the other side are communicated with the rod cavity and rodless cavity of oil cylinder by pipeline respectively, pressure compensator is connected in series on the pipeline of oil tank leading to proportional reversing valve, balance valve is connected in series on the pipeline of proportional reversing valve leading to the rod cavity and rodless cavity of oil cylinder respectively, pressure switch is set on the pipeline between balance valve and the rodless cavity of oil cylinder.It is little affected by load pressure variation, improve synchronization accuracy, guarantee centering effect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of hydraulic control equipment, and relates to a centering hydraulic system of an aluminum ingot tipping device. BACKGROUND

[0002] The aluminum ingot tipping device is used to overturn the aluminum ingot, and the centering operation needs to be performed on the aluminum ingot during the overturning of the aluminum ingot. The centering system is used to realize the centering action. The centering system comprises four executing mechanisms and four oil cylinders. Each executing mechanism is driven by an oil cylinder. The piston rods of the four oil cylinders are synchronously extended, and the corresponding executing mechanisms are also synchronously extended. After the four executing mechanisms all contact the aluminum ingot, the aluminum ingot is pushed to the middle position. With the pressure rising and reaching the set value of the pressure switch, it is indicated that the centering action is completed. Traditionally, in order to keep the synchronous action of the four oil cylinders, a synchronous valve or a synchronous motor is usually used. Each synchronous valve or synchronous motor controls one oil cylinder. Since the friction force borne by each executing mechanism is variable, the friction forces borne by the executing mechanisms are not equal, which leads to the fact that the loads borne by the oil cylinders are not equal, and it is very difficult to control the synchronization of the oil cylinders. Under the synchronous control mode of the existing synchronous valve or synchronous motor, the synchronization precision of the oil cylinders is poor. SUMMARY

[0003] In view of this, the purpose of the present application is to provide a centering hydraulic system of an aluminum ingot tipping device, so as to solve the problem of poor centering synchronization precision in the existing centering operation.

[0004] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0005] A centering hydraulic system of an aluminum ingot tipping device, comprising four executing mechanisms with synchronous action, four oil cylinders with synchronous action and four groups of centering valve groups. The four executing mechanisms are divided into two groups which are arranged at intervals. The two executing mechanisms in each group are arranged perpendicularly to each other. Each executing mechanism is driven by an oil cylinder. Each oil cylinder is controlled by a group of centering valve groups. The centering valve group comprises a proportional reversing valve with valve core position feedback, a pressure compensator, a balance valve and a pressure switch. The oil inlet and the oil outlet on one side of the proportional reversing valve with valve core position feedback are communicated with the oil tank through pipelines. The two oil outlets on the other side of the proportional reversing valve are communicated with the rod cavity and the rodless cavity of the oil cylinder through pipelines. The pressure compensator is connected in series on the pipeline from the oil tank to the proportional reversing valve. The balance valve is connected in series on the pipelines from the proportional reversing valve to the rod cavity and the rodless cavity of the oil cylinder. The pressure switch is arranged on the pipeline between the balance valve and the rodless cavity of the oil cylinder.

[0006] Further, the encoder for measuring the stroke of the oil cylinder is further included.

[0007] Further, each two groups of centering valve groups are integrated on one valve table to form an integral whole.

[0008] The present application has the following beneficial effects:

[0009] (1) The invention adopts the combination of proportional reversing valve with valve core position feedback + inlet pressure compensator + balance valve + pressure switch for the centering valve group, and forms a hydraulic control circuit together with the oil cylinder. The proportional reversing valve with valve core position feedback ensures that the valve core position is the same when a certain proportional signal is given, reducing the influence of hydraulic force on the valve core. The function of the pressure compensator is to keep the pressure difference Δp acting on the proportional reversing valve port constant when the valve core is in the balance position and the load pressure changes. Since the pressure compensator has obvious shortcomings: it cannot work normally during deceleration braking, especially when the deceleration braking pressure is higher than the pressure difference at the valve port set by the proportional reversing valve spring, so the balance valve is added to ensure smooth deceleration braking and ensure the normal work of the pressure compensator. Compared with the synchronous control mode using synchronous valve or synchronous motor, the invention has better adaptability to load pressure changes and higher synchronization accuracy.

[0010] (2) The invention detects the oil cylinder stroke through the encoder, integrates the encoder into the hydraulic control circuit, and improves the control accuracy.

[0011] Other advantages, objects and features of the present invention will be set forth in part in the following specification, and in part will become apparent to those skilled in the art from a consideration of the following specification, or can be learned from practice of the invention. The objects and other advantages of the present invention can be realized and attained by the following description. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to make the purpose, technical scheme and advantages of the present invention clearer, the preferred detailed description of the present invention will be given below in combination with the drawings, in which:

[0013] Fig. 1 The figure is a schematic diagram of the arrangement of each actuator of the present invention;

[0014] Fig. 2 The figure is a schematic diagram of the principle of the centering valve group of the present invention;

[0015] Fig. 3 The figure is a schematic diagram of the structure of the centering valve group of the present invention.

[0016] Reference signs: pressure compensator 1, pressure reducing valve 11, shuttle valve 12, proportional reversing valve 2, balance valve 3, pressure switch 4, oil cylinder 5, valve table 6, actuator 7. DETAILED DESCRIPTION

[0017] The present application is described and explained more fully with reference to the following detailed description. Other advantages of the present application will be realized and appreciated by those skilled in the art, and it will be understood to those skilled in the art that the application can be practiced with modification and alteration, and that the statement and drawings should be construed as illustrative only. Furthermore, it will be understood to those skilled in the art that the following description of exemplary embodiments of the present application are not limiting of the present application, but merely illustrate the principles of the present application. Other embodiments of the present application limited only by the metes and bounds of the appended claims.

[0018] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0019] The same or similar components in the drawings of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it should be understood that the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front", "back" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the position relationship in the drawings are only for illustrative purposes, and cannot be understood as a limitation of the present application, for those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0020] Please refer to Figs. 1-3 The present application is a centering hydraulic system of an aluminum ingot tipping device, which comprises four actuators 7, four oil cylinders 5 and four sets of centering valve groups. The four actuators 7 are arranged in two groups at intervals, and the two actuators 7 in each group are arranged perpendicular to each other. Each actuator 7 is driven by an oil cylinder 5, and each oil cylinder 5 is controlled by a set of centering valve groups.

[0021] The centering valve group comprises a proportional directional valve 2 with valve core position feedback, a pressure compensator 1, a balance valve 3 and a pressure switch 4. The inlet port P and the outlet port T on one side of the proportional directional valve 2 with valve core position feedback are communicated with the oil tank through pipelines, the outlet port A on the other side is communicated with the rodless chamber of the oil cylinder 5 through a pipeline, and the outlet port B is communicated with the rod chamber of the oil cylinder 5 through a pipeline. The pressure compensator 1 is connected in series on the pipeline from the oil tank to the proportional directional valve 2, the balance valve 3 is connected in series on the pipelines from the proportional directional valve 2 to the rod chamber and the rodless chamber of the oil cylinder 5, and the pressure switch 4 is arranged on the pipeline between the balance valve 3 and the rodless chamber of the oil cylinder 5.

[0022] In this embodiment, the pressure compensator 1 comprises a pressure reducing valve 11 and a shuttle valve 12 connected thereto, the pressure reducing valve 11 is connected in series in the pipeline from the oil tank to the proportional directional valve 2, and the shuttle valve 12 is connected to the two pipelines between the proportional directional valve 2 and the balance valve 3 respectively.

[0023] The hydraulic system further comprises an encoder for measuring the stroke of the oil cylinder 5, the encoder is arranged below the oil cylinder 5, and the oil cylinder 5 pulls out the encoder when it is extended, the displacement of the oil cylinder 5 corresponds to the value of the encoder, so that the stroke of the oil cylinder 5 is measured in real time through the encoder, and the stroke parameter of the oil cylinder 5 is fed back to the proportional directional valve 2, the signal of the proportional directional valve 2 is adjusted by using the electric control program, and then the speed of the oil cylinder 5 is adjusted, so as to realize the closed-loop control of the displacement and speed of the oil cylinder 5.

[0024] In order to make the structure more compact, every two groups of centering valve groups are integrated on a valve table 6 to form a whole. The two groups of centering valve groups on the valve table 6 are arranged symmetrically, and the proportional directional valve 2, the pressure compensator 1, the balance valve 3 and the pressure switch 4 included in the centering valve group are arranged on the valve table 6 in the position relationship from top to bottom.

[0025] In this embodiment, the piston rods of the four oil cylinders 5 are synchronously extended to drive the corresponding executing mechanisms 7 to synchronously extend, and before the executing mechanisms 7 contact the aluminum ingot, the load pressure P2 of each executing mechanism 7 is the friction force. Since the pressure compensator 1+balance valve 3 is configured, the pressure difference before and after the proportional directional valve 2 at this time is Δp=P1-P2=Fr / A1=constant, wherein P1 is the pressure before the valve, P2 is the pressure after the valve, which is also the load pressure, Fr is the spring force, and A1 is the acting area of the spring. When the load pressure P2 changes, as long as the additional pressure difference Ps-P2>the set value of the pressure compensator 1, and Ps is the additional pressure, the flow control function can be realized, and the pressure difference before and after the proportional directional valve 2 is constant.

[0026] When the oil flows in the proportional directional valve 2, the oil hydraulic force is affected. When the ordinary proportional directional valve 2 is used, a certain proportional signal is given, at this time the spool of the proportional directional valve 2 will be affected by the oil hydraulic force, and the opening degree of the proportional directional valve 2 will be different. The proportional directional valve 2 with spool position feedback can improve the position accuracy of the opening degree of the proportional directional valve 2, and then ensure that the flow area of the proportional directional valve 2 is the same.

[0027] According to the flow formula Q=Cd·A·Δp, Cd is the flow coefficient of the valve, which is related to the Reynolds number, A is the flow area of the valve, and Δp is the pressure difference before and after the valve. To ensure that the speeds of the oil cylinders 5 and the executing mechanisms 7 are synchronous, it is necessary to ensure that the oil flow is constant, as long as the three parameters Cd, A and Δp affecting the flow are constant, then the speeds of the oil cylinders 5 and the executing mechanisms 7 are the same.

[0028] In the centering operation, the piston rods of the four oil cylinders 5 are synchronously extended, driving the actuating mechanisms 7 connected thereto to synchronously extend. When the two actuating mechanisms 7 of one group first contact the aluminum ingot, the corresponding valve rear pressure P2 will rise to a force that can push the aluminum ingot. As long as PS-P2 is greater than the set value of the pressure compensator 1, the pressure compensator 1 will still function, and the front and rear pressure difference Δp of the proportional directional valve 2 will remain unchanged (if PS-P2 is less than the set value of the pressure compensator 1, the pressure compensator 1 will not function, and at this time the front and rear pressure difference of the proportional directional valve 2 will be affected by the load pressure). The two actuating mechanisms 7 of the other group have not yet contacted the aluminum ingot, and the corresponding front and rear pressure difference of the directional proportional valve is also Δp, which is the same as that of the actuating mechanisms 7 of the group that has contacted the aluminum ingot. Therefore, at this time the two groups of actuating mechanisms 7 remain synchronized. Until the two groups of actuating mechanisms 7 also contact the aluminum ingot, and the pressure of the rodless chambers of the four oil cylinders 5 all rise to the set value of the pressure switch 4, and the stroke error of the oil cylinders 5 displayed by the encoders corresponding to the two groups of actuating mechanisms that have contacted the aluminum ingot is less than 30 mm, it is indicated that the centering operation is completed.

[0029] The centering hydraulic system of the aluminum ingot tipping device provided by the embodiment uses a proportional directional valve 2 with valve core position feedback + an inlet pressure compensator 1 + a balance valve 3 + a pressure switch 4 combination for the centering valve group, combined with closed-loop control with an encoder, which is less affected by load changes, improves synchronization accuracy, and ensures the centering effect.

[0030] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the purpose and scope of the technical solutions, and they should all be included in the scope of the claims of the present application.

Claims

1. A centering hydraulic system for an aluminum ingot tipping apparatus, characterized by: The four actuators include a synchronous action, four synchronous oil cylinders and four sets of centering valve groups, the four actuators are divided into two groups arranged at intervals, the two actuators in each group are arranged perpendicularly to each other, each actuator is driven by an oil cylinder, and each oil cylinder is controlled by a set of centering valve groups; the centering valve group includes a proportional directional valve with valve core position feedback, a pressure compensator, a balance valve and a pressure switch; the oil inlet and the oil outlet on one side of the proportional directional valve with valve core position feedback are communicated with an oil tank through pipelines, the two oil outlets on the other side are communicated with the rod cavity and the rodless cavity of the oil cylinder through pipelines, the pressure compensator is connected in series on the pipeline from the oil tank to the proportional directional valve, the balance valves are connected in series on the pipelines from the proportional directional valve to the rod cavity and the rodless cavity of the oil cylinder, and the pressure switch is arranged on the pipeline between the balance valve and the rodless cavity of the oil cylinder; the pressure compensator includes a pressure reducing valve and a shuttle valve connected with the pressure reducing valve, the pressure reducing valve is connected in series on the pipeline from the oil tank to the proportional directional valve, and the shuttle valve is communicated with the two pipelines between the proportional directional valve and the balance valve; the encoder for measuring the stroke of the oil cylinder is further included, the encoder is arranged below the oil cylinder, the oil cylinder pulls out the encoder when the oil cylinder is extended, the displacement of the oil cylinder corresponds to the value of the encoder, so that the stroke of the oil cylinder is measured in real time through the encoder, and the stroke parameter of the oil cylinder is fed back to the proportional directional valve, the signal of the proportional directional valve is adjusted by using the electric control program, and then the speed of the oil cylinder is adjusted, so that the closed-loop control of the displacement and the speed of the oil cylinder is realized; two sets of centering valve groups are integrated on a valve table to form an integral whole, and the two sets of centering valve groups on the valve table are arranged symmetrically, and the proportional directional valve, the pressure compensator, the balance valve and the pressure switch included in the centering valve group are arranged on the valve table in the position relationship from top to bottom; The piston rods of the four oil cylinders are synchronously extended to drive the corresponding actuators to synchronously extend, before the actuators contact the aluminum ingot, the load pressure P2 of each actuator is the friction force, since the pressure compensator and the balance valve are arranged, the pressure difference before and after the proportional directional valve is Δp=P1-P2=Fr / A1 =constant, wherein P1 is the pressure before the valve, P2 is the pressure after the valve, which is also the load pressure, Fr is the spring force, and A1 is the acting area of the spring, when the load pressure P2 changes, as long as the additional pressure difference Ps-P2>the set value of the pressure compensator, and Ps is the additional pressure, the flow control effect can be achieved, and the pressure difference before and after the proportional directional valve is ensured to be constant.

Images