Variable clamping force oil way control system of double-acting stretch forming equipment

Abstract

The invention belongs to the technical field of oil way control, and particularly discloses a variable clamping force oil way control system of double-acting stretch forming equipment, which comprises a first pump group, a first pump source control valve group, a second pump group, a second pump source control valve group, a locking control valve, a blank pressing cylinder prefill valve, a middle main cylinder prefill valve and a valve group assembly, the middle main cylinder is connected with a middle sliding block; the edge pressing cylinder is connected with the edge pressing sliding block, and the locking device locks the edge pressing sliding block and the middle sliding block. The valve set assembly comprises a two-pump confluence control valve set, a blank pressing cylinder lower cavity control valve set, a blank pressing cylinder upper cavity control valve set, a blank pressing cylinder upper cavity pressure control valve set, a middle main cylinder lower cavity control valve set, a middle main cylinder upper cavity control valve set, a middle main cylinder upper cavity pressure control valve set, a prefill valve set and a system pressure control valve set. Under the condition that the requirement of a common double-acting forming process is met, a single main cylinder pressing process of a small die forming process and a main cylinder and edge pressing cylinder simultaneous pressing process of a large die forming process are added, and the effect that one press has multiple purposes is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil circuit control, and in particular relates to a variable clamping force oil circuit control system for double-action stretch forming equipment. Background Art

[0002] Reducing energy consumption, reducing environmental pollution and saving limited resources are currently a very important and urgent issue facing my country. From a general perspective, the number of equipment directly determines the size of a required plant, which in turn determines the amount of land resources occupied, and also directly determines the amount of water, electricity, gas and other energy used by the equipment; from a detailed perspective, the clamping force, speed, energy, control, environment, etc. of a single device are the core content of the product required by the user.

[0003] Double-acting stretch forming presses are generally hydraulic equipment that uses a main oil cylinder and multiple pressure cylinders. In actual applications, they can produce products that meet objective needs with the least resources. Diversity and energy saving have become inevitable in the development of the market, which puts higher requirements on the clamping force, speed and flexibility of the press. Therefore, the high-precision and flexible control of the clamping force, speed, flow and other performance of the main cylinder and the pressure cylinder is the focus of this type of equipment. This also determines that this type of equipment usually uses multiple sets of pump groups, high noise, large installed power of the hydraulic system, complex logic control logic, large hydraulic station structure, and large demand for hydraulic oil volume, which in turn leads to high costs, many failure points, many oil leakage risk points, and difficult maintenance and high workload. Summary of the invention

[0004] The purpose of the present invention is to provide a variable clamping force oil circuit control system for double-action stretch forming equipment, which can increase the single main cylinder pressing process of the small mold forming process and increase the main cylinder and edge pressing cylinder simultaneous pressing process of the large mold forming process under the condition of meeting the requirements of the ordinary double-action forming process, so as to achieve the effect of multiple uses of one press machine and greatly reduce the equipment cost. It reduces energy use, press noise, site use, oil demand of the hydraulic system, simplifies the valve group control unit, and also reduces the cost of the hydraulic system to a certain extent, reduces the failure points and oil leakage risk points, and is simple and convenient to maintain.

[0005] In order to achieve the above-mentioned purpose, the technical scheme of the present invention is: a variable clamping force oil circuit control system for double-action stretching forming equipment, comprising a first pump group, a first pump source control valve group, a second pump group, a second pump source control valve group, a locking control valve, a margin cylinder filling valve, a middle master cylinder filling valve and a valve group assembly; the double-action stretching forming equipment comprises a middle master cylinder and multiple groups of margin cylinders, and the middle master cylinder is connected to the middle slider; each group of the margin cylinders is connected to a margin slider, and each group of the margin sliders corresponds to a group of locking devices, and the locking device is used to lock the margin slider with the middle slider; the locking control valve is respectively connected to multiple groups of locking devices and controls the locking devices; the bottom of each group of the margin cylinders is connected to the margin cylinder filling valve, and the bottom of the middle master cylinder is connected to the middle master cylinder filling valve; the first pump source control valve group is used to control the first pump group, and the second pump source control valve group is used to control the second pump group;

[0006] The valve group assembly includes a two-pump confluence control valve group, a side pressing cylinder lower chamber control valve group, a side pressing cylinder upper chamber control valve group, a side pressing cylinder upper chamber pressure control valve group, a middle master cylinder lower chamber control valve group, a middle master cylinder upper chamber control valve group, a middle master cylinder upper chamber pressure control valve group, a filling valve group, and a system pressure control valve group; the filling valve group and the system pressure control valve group are connected; the first pump source control valve group is connected to the two-pump confluence control valve group, and the second pump source control valve group is respectively connected to the two-pump confluence control valve group, the middle master cylinder lower chamber control valve group, the middle master cylinder upper chamber control valve group, the filling valve group and the system pressure control valve group; the two-pump confluence control valve group is also connected to the lower chamber control valve group of the side pressing cylinder and the upper chamber control valve group of the side pressing cylinder. The cavity control valve group, the lower cavity control valve group of the middle master cylinder, the upper cavity control valve group of the middle master cylinder, the locking control valve, the filling valve group and the system pressure control valve group are connected; the upper cavity control valve group of the edge pressing cylinder is connected to the upper cavity pressure control valve group of the edge pressing cylinder, and the upper cavity control valve group of the middle master cylinder is connected to the upper cavity pressure control valve group of the middle master cylinder; the lower cavity control valve group of the edge pressing cylinder is respectively connected to the lower cavities of multiple groups of the edge pressing cylinders, and the upper cavity control valve group of the edge pressing cylinder is respectively connected to the upper cavities of multiple groups of the edge pressing cylinders, the lower cavity control valve group of the middle master cylinder is connected to the lower cavity of the middle master cylinder, and the upper cavity control valve group of the middle master cylinder is connected to the upper cavity of the middle master cylinder; the middle master cylinder filling valve and the edge pressing cylinder filling valve are respectively connected to the filling valve groups.

[0007] Furthermore, the lower chamber control valve group of the edge pressing cylinder and the lower chamber control valve group of the middle master cylinder respectively control the oil inlet, oil discharge and support of the lower chamber of the edge pressing cylinder and the lower chamber of the middle master cylinder, and the upper chamber control valve group of the edge pressing cylinder and the upper chamber control valve group of the middle master cylinder respectively control the oil inlet and pressure maintenance of the upper chamber of the edge pressing cylinder and the upper chamber of the middle master cylinder.

[0008] Furthermore, the two-pump confluence control valve group includes a solenoid valve, a first cartridge valve and a shuttle valve. The solenoid valve is connected to the control chamber of the first cartridge valve and is used to open and close the first cartridge valve. The A port of the first cartridge valve is respectively connected to the first pump source control valve group, the upper chamber control valve group of the edge pressure cylinder, the lower chamber control valve group of the edge pressure cylinder and the locking control valve; the B port of the first cartridge valve is respectively connected to the second pump source control valve group, the lower chamber control valve group of the middle master cylinder, the upper chamber control valve group of the middle master cylinder, the filling valve group and the system pressure control valve group; the oil outlet of the shuttle valve is connected to the solenoid valve, and the two oil inlets of the shuttle valve are respectively connected to the A port and the B port of the first cartridge valve.

[0009] Furthermore, the upper chamber pressure control valve group of the edge pressure cylinder and the upper chamber pressure control valve group of the middle master cylinder both include a proportional relief valve, a relief valve, a second cartridge valve and a proportional valve filter. The proportional relief valve, the relief valve, the control chamber of the second cartridge valve and the proportional valve filter are connected together, and the proportional valve filter is connected to the oil port of the second cartridge valve.

[0010] Furthermore, the filtering accuracy of the proportional valve filter is not higher than 10μ.

[0011] Furthermore, the pressure limit condition of the first pump source control valve group and the second pump source control valve group is not less than 26Mpa; the pressure of the external pressure oil of the side pressure cylinder filling valve and the middle master cylinder filling valve is not higher than 5Mpa; the high pressure limit condition of the valve assembly is not less than 26Mpa, and the low pressure limit condition is not higher than 5MPa.

[0012] Furthermore, the edge pressing slider is connected to a edge pressing cylinder displacement sensor, and the middle slider is connected to a middle master cylinder displacement sensor.

[0013] Furthermore, the first pump group and the second pump group are high-pressure servo pump groups.

[0014] Furthermore, the lower chamber control valve group of the edge pressure cylinder and the lower chamber control valve group of the middle master cylinder both include an oil inlet valve, an oil outlet valve, a support valve and a quick lower valve; the upper chamber control valve group of the edge pressure cylinder and the upper chamber control valve group of the middle master cylinder both include an oil inlet valve and a pressure maintaining valve.

[0015] The working principle of this technical solution is:

[0016] Double-action process: When the press starts running, the press's edge-pressing slider moves downward quickly due to its own weight, and negative pressure is formed in the upper chamber of the edge-pressing cylinder, which sucks open the filling valve of the edge-pressing cylinder to fill the oil in the edge-pressing cylinder. The support valve and the quick-down valve of the edge-pressing cylinder lower chamber control valve group are opened to quickly drain the oil from the lower chamber of the edge-pressing cylinder. The edge-pressing cylinder displacement sensor transmits the displacement signal for control, so that the fast-to-slow flexible speed curve is perfectly connected with the pressing speed, and the mold is closed quickly and smoothly without impact. The edge-pressing process action is realized through the edge-pressing cylinder upper chamber control valve group and the edge-pressing cylinder upper chamber pressure control valve group. The pressure can be controlled by the proportional relief valve in the edge-pressing cylinder upper chamber pressure control valve group to realize the edge-pressing process action with different edge-pressing forces. Then the middle slider of the press moves down quickly under its own weight, and the upper chamber of the middle master cylinder forms negative pressure, sucking open the filling valve of the middle master cylinder to fill the middle master cylinder with oil. The support valve and the quick lower valve of the middle master cylinder lower chamber control valve group are opened, so that the lower chamber of the middle master cylinder can be quickly drained of oil. The displacement signal is transmitted by the middle master cylinder displacement sensor to control the fast-to-slow flexible speed curve and the pressing speed to achieve a perfect connection, and fast, stable and impact-free mold closing. The double-action pressing process action is realized by the middle master cylinder upper chamber control valve group and the middle master cylinder upper chamber pressure control valve group. The proportional relief valve in the middle master cylinder upper chamber pressure control valve group can be pressure-controlled to realize the double-action pressing process action with different clamping forces. Finally, the middle master cylinder is depressurized and returned, and the edge pressure cylinder is depressurized and returned to complete the entire process action. In this process action, the two pump confluence control valve group can be opened to realize the two pumps working together to provide oil to the cylinder, meet the high-speed beat requirements, and save various costs.

[0017] Single-action process for the pressing process of small molds and small clamping force: When the press starts running, the middle slide of the press moves down quickly under its own weight, and the upper chamber of the middle master cylinder forms a negative pressure, sucking open the filling valve of the middle master cylinder to fill the middle master cylinder with oil. The support valve and the quick lower valve of the middle master cylinder lower chamber control valve group are opened, so that the lower chamber of the middle master cylinder can be quickly drained of oil. The displacement signal is transmitted by the middle master cylinder displacement sensor to control the fast-to-slow flexible speed curve and the pressing speed to achieve a perfect connection, and fast and stable mold closing without impact. The double-action pressing process action is realized by the middle master cylinder upper chamber control valve group and the middle master cylinder upper chamber pressure control valve group. The proportional overflow valve in the middle master cylinder upper chamber pressure control valve group can be pressure-controlled to realize the double-action pressing process action with different clamping forces. Finally, the middle master cylinder is depressurized and returns to complete the entire process action. When the speed of one set of pump groups can meet the requirements, the other set of pump groups can be stopped, which greatly saves energy costs. In this process action, the two pump confluence control valve group can be opened to enable the two pumps to work together to provide oil to the cylinder, meet the high-speed beat requirements, and save various costs.

[0018] Single-action process for large molds and large clamping force pressing process: When the press starts running, the pressure oil from the first pump group or the second pump group is first controlled by the locking control valve, and the edge pressing slide and the middle slide are locked together by the locking device. The two pump confluence control valve group is opened to keep the total oil circuit of the edge pressing cylinder and the middle main cylinder connected, and then the connected edge pressing slide and the middle slide are quickly lowered by their own weight, and the upper chambers of the edge pressing cylinder and the middle main cylinder are negatively pressurized, sucking open the edge pressing cylinder filling valve and the middle main cylinder filling valve to fill the edge pressing cylinder and the middle main cylinder with oil. The support valve and the quick down valve of the edge pressing cylinder lower chamber control valve group and the support valve and the quick down valve of the middle main cylinder lower chamber control valve group are opened together, so that the lower chambers of the edge pressing cylinder and the middle main cylinder are quickly drained. The displacement signal is transmitted by the edge pressing cylinder displacement sensor and the middle main cylinder displacement sensor for control, so that the fast-to-slow flexible speed curve is perfectly connected with the pressing speed, and the mold is closed quickly and smoothly without impact. The pressing process action is realized by the upper chamber control valve group of the edge pressing cylinder, the upper chamber pressure control valve group of the edge pressing cylinder, the upper chamber control valve group of the middle master cylinder and the upper chamber pressure control valve group of the middle master cylinder, wherein the pressure can be controlled by the proportional overflow valve in the upper chamber pressure control valve group of the edge pressing cylinder and the proportional overflow valve in the upper chamber pressure control valve group of the middle master cylinder to realize single-action pressing process action with different clamping forces; finally, the middle master cylinder and the edge pressing cylinder release pressure and return to complete the whole process action.

[0019] The beneficial effects of this technical solution are:

[0020] According to the characteristics of the double-action stretch forming process, two relatively independent high-pressure servo pump groups (the first pump group and the second pump group) are used. Under the control of the proportional relief valve, while meeting the requirements of the ordinary double-action forming process, the single main cylinder pressing process of the small mold forming process is added, and the large mold and large clamping force forming process is added when the edge pressing slide and the middle slide are locked together. The main cylinder and the edge pressing cylinder simultaneously press the large mold and large clamping force forming process, so as to achieve the effect of a press machine for multiple uses. It not only greatly reduces the equipment cost, but also reduces energy use, environmental pollution and site use. At the same time, it reduces the oil demand of the hydraulic system, simplifies the valve group control unit, improves the flexibility and reliability of the whole machine operation, and also reduces the failure points and oil leakage risk points to a certain extent, and the maintenance is simple and convenient. It can better realize the fast, flexible, high-precision and high-reliability forming function requirements of the double-action forming press.

[0021] The whole machine hydraulic system adopts two relatively independent high-pressure servo pump groups (the first pump group and the second pump group), which provide power to the middle main cylinder and the edge pressing cylinder respectively when the two pump confluence control valve groups are not connected. When the two pump confluence control valve groups are connected, firstly, the speed of the middle main cylinder or the edge pressing cylinder can be increased to reduce the cycle time. Secondly, after the edge pressing slide and the middle slide are locked with the locking device, the high-pressure servo pump group provides power to the middle main cylinder and the edge pressing cylinder at the same time to realize the pressing process action.

[0022] When using small molds and small tonnage, the edge holding cylinder can be in a stationary state. If the second pump group can meet the speed requirements of the middle main cylinder, the high-pressure servo pump group of the first pump group connected to the edge holding cylinder will also be in a stationary state, saving energy consumption.

[0023] The pressure of the edge pressing cylinder and the middle main cylinder is controlled by a proportional relief valve, and the first pump group and the second pump group adopt speed open-loop control, which only controls the speed of the edge pressing cylinder and the middle main cylinder to simplify the electrical logic. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a schematic structural diagram of a variable clamping force oil circuit control system for a double-action stretch forming device. DETAILED DESCRIPTION

[0025] The following is further described in detail through specific implementation methods:

[0026] The figure marks in the drawings of the specification include: first pump group 1, second pump group 2, first pump source control valve group 3, second pump source control valve group 4, valve group assembly 5, two pump confluence control valve group 6, edge pressing cylinder lower chamber control valve group 7, edge pressing cylinder upper chamber control valve group 8, middle master cylinder lower chamber control valve group 9, middle master cylinder upper chamber control valve group 10, filling valve valve group 11, system pressure control valve group 12, edge pressing cylinder upper chamber pressure control valve group 13, middle master cylinder upper chamber pressure control valve group 14, locking control valve 15, middle master cylinder 16, edge pressing cylinder 17, middle slider 18, edge pressing slider 19, locking device 20, edge pressing cylinder filling valve 21, middle master cylinder filling valve 22, edge pressing cylinder displacement sensor 23, middle master cylinder displacement sensor 24, oil tank 25.

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The embodiment is basically as shown in the attached Figure 1As shown: a variable clamping force oil circuit control system of a double-action stretch forming device, comprising a first pump group 1, a first pump source control valve group 3, a second pump group 2, a second pump source control valve group 4, a locking control valve 15, a pressure cylinder filling valve 21, a middle main cylinder filling valve 22 and a valve group assembly 5. The double-action stretch forming device comprises a middle main cylinder 16 and a plurality of symmetrical pressure cylinders 17. Usually, the pressure cylinders 17 are an even number. In this embodiment, the number of pressure cylinders 17 is 2. The middle main cylinder 16 is connected to the middle slider 18; each group of pressure cylinders 17 is connected to a pressure slider 19, and each group of pressure sliders 19 corresponds to a group of locking devices 20 (specifically, a locking cylinder is used), and the locking device 20 is used to lock the pressure slider 19 with the middle slider 18. The locking control valve 15 is respectively connected to the plurality of locking devices 20 and controls the locking devices 20. The bottom of each group of edge pressing cylinders 17 is connected to the edge pressing cylinder filling valve 21, and the bottom of the middle master cylinder 16 is connected to the middle master cylinder filling valve 22. The first pump source control valve group 3 is used to control the first pump group 1, and the second pump source control valve group 4 is used to control the second pump group 2; the bottoms of the first pump group 1, the second pump group 2, the middle master cylinder 16 and the edge pressing cylinder 17 are respectively connected to the oil tank 25.

[0029] The valve group assembly 5 includes a two-pump confluence control valve group 6, a side pressing cylinder lower chamber control valve group 7, a side pressing cylinder upper chamber control valve group 8, a side pressing cylinder upper chamber pressure control valve group 13, a middle master cylinder lower chamber control valve group 9, a middle master cylinder upper chamber control valve group 10, a middle master cylinder upper chamber pressure control valve group 14, a filling valve group 11, and a system pressure control valve group 12; the filling valve group 11 and the system pressure control valve group 12 are connected. The first pump source control valve group 3 is connected to the two-pump confluence control valve group 6, and the second pump source control valve group 4 is respectively connected to the two-pump confluence control valve group 6, the middle master cylinder lower chamber control valve group 9, the middle master cylinder upper chamber control valve group 10, the filling valve group 11 and the system pressure control valve group 12; the two-pump confluence control valve group 6 is also connected to the edge pressing cylinder lower chamber control valve group 7, the edge pressing cylinder upper chamber control valve group 8, the middle master cylinder lower chamber control valve group 9, the middle master cylinder upper chamber control valve group 10, the locking control valve 15, the filling valve group 11 and the system pressure control valve group 12; The cavity control valve group 8 is connected to the upper cavity pressure control valve group 13 of the edge pressing cylinder, and the upper cavity control valve group 10 of the middle master cylinder is connected to the upper cavity pressure control valve group 14 of the middle master cylinder; the lower cavity control valve group 7 of the edge pressing cylinder is respectively connected to the lower cavities of multiple groups of edge pressing cylinders 17, the upper cavity control valve group 8 of the edge pressing cylinder is respectively connected to the upper cavities of multiple groups of edge pressing cylinders 17, the lower cavity control valve group 9 of the middle master cylinder is connected to the lower cavity of the middle master cylinder 16, and the upper cavity control valve group 10 of the middle master cylinder is connected to the upper cavity of the middle master cylinder 16; the middle master cylinder filling valve 22 and the edge pressing cylinder filling valve 21 are respectively connected to the filling valve group 11.

[0030] The lower chamber control valve group 7 of the edge pressing cylinder and the lower chamber control valve group 9 of the middle master cylinder respectively control the oil inlet, oil discharge and support of the lower chamber of the edge pressing cylinder 17 and the lower chamber of the middle master cylinder 16. The lower chamber control valve group 7 of the edge pressing cylinder and the lower chamber control valve group 9 of the middle master cylinder both include an oil inlet valve, an oil outlet valve, a support valve and a quick lower valve. The upper chamber control valve group 8 of the edge pressing cylinder and the upper chamber control valve group 10 of the middle master cylinder respectively control the oil inlet and pressure maintenance of the upper chamber of the edge pressing cylinder 17 and the upper chamber of the middle master cylinder 16. The upper chamber control valve group 8 of the edge pressing cylinder and the upper chamber control valve group 10 of the middle master cylinder both include an oil inlet valve and a pressure maintenance valve.

[0031] The pressure control valve group 13 of the upper chamber of the edge pressure cylinder and the pressure control valve group 14 of the upper chamber of the middle master cylinder both include a proportional relief valve (BY1, BY2), a relief valve (F1, F2), a second cartridge valve (CZ2, CZ3) and a proportional valve filter (NL1, NL2). The proportional relief valve, the relief valve, the control chamber of the second cartridge valve and the proportional valve filter are connected together, and damping is provided between the junction and the second cartridge valve, the proportional relief valve and the proportional valve filter. The proportional valve filter and the pressure cylinder upper chamber control valve group 8 or the middle master cylinder upper chamber control valve group 10 are connected to the oil port of the second cartridge valve. The oil ports of the proportional relief valve, the relief valve and the second cartridge valve are all connected to the oil tank. The filtering accuracy of the proportional valve filter is not higher than 10μ.

[0032] The two-pump confluence control valve group 6 includes a solenoid valve (YV1), a first cartridge valve (CZ1) and a shuttle valve (C). The solenoid valve is connected to the control chamber of the first cartridge valve and is used to open and close the first cartridge valve. The A port of the first cartridge valve is respectively connected to the first pump source control valve group 3, the edge pressure cylinder upper chamber control valve group 8, the edge pressure cylinder lower chamber control valve group 7 and the locking control valve 15; the B port of the first cartridge valve is respectively connected to the second pump source control valve group 4, the middle master cylinder lower chamber control valve group 9, the middle master cylinder upper chamber control valve group 10, the filling valve group 11 and the system pressure control valve group 12; the oil outlet of the shuttle valve is connected to the solenoid valve, and the two oil inlets of the shuttle valve are respectively connected to the A port and the B port of the first cartridge valve.

[0033] The first pump group 1 and the second pump group 2 adopt high-pressure servo pump groups, and the pressure limit condition of the first pump source control valve group 3 and the second pump source control valve group 4 is not less than 26Mpa; the pressure of the external pressure oil of the side cylinder filling valve 21 and the middle main cylinder filling valve 22 is not higher than 5Mpa; the high-pressure limit condition of the valve assembly is not less than 26Mpa, and the low-pressure limit condition is not higher than 5MPa.

[0034] The edge pressing slider 19 is connected to a edge pressing cylinder displacement sensor 23 , and the middle slider 18 is connected to a middle master cylinder displacement sensor 24 .

[0035] The specific implementation process is as follows:

[0036] Double-action process: When the press starts running, the press's edge-holding slider 19 moves downward quickly by its own weight, and negative pressure is formed in the upper chamber of the edge-holding cylinder 17, sucking open the edge-holding cylinder filling valve 21 to fill the edge-holding cylinder 17 with oil. The support valve and the quick-down valve of the edge-holding cylinder lower chamber control valve group 7 are opened, so that the lower chamber of the edge-holding cylinder 17 is quickly drained of oil. The edge-holding cylinder displacement sensor 23 transmits the displacement signal for control, so that the fast-to-slow flexible speed curve is perfectly connected with the pressing speed, and the mold is closed quickly and smoothly without impact. The edge-holding process action is realized by the edge-holding cylinder upper chamber control valve group 8 and the edge-holding cylinder upper chamber pressure control valve group 13, where the pressure can be controlled by the proportional relief valve (BY1) in the edge-holding cylinder upper chamber pressure control valve group 13 to realize the edge-holding process action with different edge-holding forces. Then the middle slider 18 of the press moves down quickly by its own weight, and the upper chamber of the middle master cylinder 16 forms a negative pressure, sucking open the middle master cylinder filling valve 22, filling the middle master cylinder 16 with oil, and opening the support valve and the quick lower valve of the middle master cylinder lower chamber control valve group 9, so that the lower chamber of the middle master cylinder 16 can be quickly drained of oil, and the displacement signal is transmitted by the middle master cylinder displacement sensor 24 for control, so as to achieve a perfect connection between the fast-to-slow flexible speed curve and the pressing speed, and fast, stable and impact-free mold closing. The double-action pressing process action is realized by the middle master cylinder upper chamber control valve group 10 and the middle master cylinder upper chamber pressure control valve group 14, wherein the proportional relief valve (BY2) in the middle master cylinder upper chamber pressure control valve group 14 can be pressure-controlled to realize the double-action pressing process action with different clamping forces. Finally, the middle master cylinder 16 is depressurized and returned, and the edge pressure cylinder 17 is depressurized and returned, completing the entire process action. In this process action, the two pump confluence control valve group 6 can be opened to realize that the two pumps work together to provide oil to the oil cylinder, meet the high-speed beat requirements, and save various costs.

[0037] Single-action process for the pressing process of small molds and small clamping force: When the press starts running, the middle slide 18 of the press moves down quickly by its own weight, and the upper chamber of the middle master cylinder 16 forms a negative pressure, sucking open the middle master cylinder filling valve 22 to fill the middle master cylinder 16 with oil, and the support valve and the quick lower valve of the middle master cylinder lower chamber control valve group 9 are opened, so that the lower chamber of the middle master cylinder 16 can be quickly drained of oil, and the displacement signal is transmitted by the middle master cylinder displacement sensor 24 for control, so as to achieve a perfect connection between the fast-to-slow flexible speed curve and the pressing speed, and close the mold quickly and smoothly without impact. The double-action pressing process action is realized by the middle master cylinder upper chamber control valve group 10 and the middle master cylinder upper chamber pressure control valve group 14, wherein the proportional relief valve (BY2) in the middle master cylinder upper chamber pressure control valve group 14 can be pressure-controlled to realize the double-action pressing process action with different clamping forces. Finally, the middle master cylinder 16 is depressurized and returns to complete the entire process action. When the speed of one set of pump groups can meet the requirements, the other set of pump groups can be stopped, which greatly saves energy costs. In this process action, the two-pump merging control valve group 6 can be opened to realize the two pumps working together to provide oil to the cylinder, meet the high-speed beat requirements, and save various costs.

[0038] Single-action process for large molds and large clamping force pressing process: When the press starts running, the pressure oil from the first pump group 1 or the second pump group 2 is first controlled by the locking control valve 15, and the edge pressing slide 19 and the middle slide 18 are locked together by the locking device 20. The two pump confluence control valve group 6 is opened to keep the total oil circuit of the edge pressing cylinder 17 and the middle main cylinder 16 connected, and then the connected edge pressing slide 19 and the middle slide 18 are quickly lowered by their own weight, and the upper chambers of the edge pressing cylinder 17 and the middle main cylinder 16 form negative pressure, sucking open the edge pressing cylinder filling valve 21 and the middle main cylinder filling valve 22, and filling the edge pressing cylinder 17 and the middle main cylinder 16 with oil. The support valve and the quick lowering valve of the edge pressing cylinder lower chamber control valve group 7 and the support valve and the quick lowering valve of the middle main cylinder lower chamber control valve group 9 are opened together, so that the lower chambers of the edge pressing cylinder 17 and the middle main cylinder 16 are quickly drained. The displacement signal is transmitted by the displacement sensor 23 of the edge pressing cylinder and the displacement sensor 24 of the middle main cylinder to realize the perfect connection between the fast-to-slow flexible speed curve and the pressing speed, and the mold is closed quickly and smoothly without impact. The pressing process action is realized by the upper chamber control valve group 8 of the edge pressing cylinder, the upper chamber pressure control valve group 13 of the edge pressing cylinder, the upper chamber control valve group 10 of the middle main cylinder and the upper chamber pressure control valve group 14 of the middle main cylinder, wherein the pressure can be controlled by the proportional overflow valve (BY1) in the upper chamber pressure control valve group 13 of the edge pressing cylinder and the proportional overflow valve (BY2) in the upper chamber pressure control valve group 14 of the middle main cylinder to realize the single-action pressing process action with different clamping forces; finally, the middle main cylinder 16 and the edge pressing cylinder 17 release the pressure and return to complete the whole process action.

[0039] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0040] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A variable clamping force oil circuit control system for double-action stretch forming equipment, characterized in that: The double-acting stretch forming device comprises a first pump group (1), a first pump source control valve group (3), a second pump group (2), a second pump source control valve group (4), a locking control valve (15), a pressure cylinder filling valve (21), a middle master cylinder filling valve (22) and a valve group assembly (5); the double-acting stretch forming device comprises a middle master cylinder (16) and a plurality of pressure cylinder groups (17), wherein the middle master cylinder (16) is connected to an intermediate slide block (18); each group of the pressure cylinders (17) is connected to a pressure slide block (19), and each group of the pressure slide blocks (19) corresponds to a locking device (20). ), the locking device (20) is used to lock the edge pressing slider (19) and the middle slider (18); the locking control valve (15) is respectively connected to multiple groups of locking devices (20) and controls the locking devices (20); the bottom of each group of edge pressing cylinders (17) is connected to the edge pressing cylinder filling valve (21), and the bottom of the middle master cylinder (16) is connected to the middle master cylinder filling valve (22); the first pump source control valve group (3) is used to control the first pump group (1), and the second pump source control valve group (4) is used to control the second pump group (2); The valve group assembly (5) comprises a two-pump confluence control valve group (6), a side pressing cylinder lower chamber control valve group (7), a side pressing cylinder upper chamber control valve group (8), a side pressing cylinder upper chamber pressure control valve group (13), a middle master cylinder lower chamber control valve group (9), a middle master cylinder upper chamber control valve group (10), a middle master cylinder upper chamber pressure control valve group (14), a filling valve group (11), and a system pressure control valve group (12); the filling valve group (11) and the system pressure control valve group (12) are The first pump source control valve group (3) is connected to the two-pump confluence control valve group (6), and the second pump source control valve group (4) is respectively connected to the two-pump confluence control valve group (6), the middle master cylinder lower chamber control valve group (9), the middle master cylinder upper chamber control valve group (10), the filling valve group (11) and the system pressure control valve group (12); the two-pump confluence control valve group (6) is also connected to the pressure cylinder lower chamber control valve group (7), the pressure cylinder upper chamber control valve group (10), the pressure cylinder lower chamber control valve group (11), and the system pressure control valve group (12). The control valve group (8), the middle master cylinder lower chamber control valve group (9), the middle master cylinder upper chamber control valve group (10), the locking control valve (15), the filling valve group (11) and the system pressure control valve group (12) are connected; the upper chamber control valve group (8) of the edge pressing cylinder is connected to the upper chamber pressure control valve group (13), the upper chamber control valve group (10) of the middle master cylinder is connected to the upper chamber pressure control valve group (14) of the middle master cylinder; the lower chamber control valve group (7 ) are respectively connected to the lower chambers of multiple groups of the edge pressing cylinders (17), the upper chamber control valve groups (8) of the edge pressing cylinders are respectively connected to the upper chambers of multiple groups of the edge pressing cylinders (17), the lower chamber control valve group (9) of the middle master cylinder is connected to the lower chamber of the middle master cylinder (16), and the upper chamber control valve group (10) of the middle master cylinder is connected to the upper chamber of the middle master cylinder (16); the middle master cylinder filling valve (22) and the edge pressing cylinder filling valve (21) are respectively connected to the filling valve group (11).

2. A variable clamping force oil circuit control system for double-action stretch forming equipment according to claim 1, characterized in that: The lower chamber control valve group (7) of the edge pressing cylinder and the lower chamber control valve group (9) of the middle master cylinder respectively control the oil inlet, oil discharge and support of the lower chamber of the edge pressing cylinder (17) and the lower chamber of the middle master cylinder (16); the upper chamber control valve group (8) of the edge pressing cylinder and the upper chamber control valve group (10) of the middle master cylinder respectively control the oil inlet and pressure maintenance of the upper chamber of the edge pressing cylinder (17) and the upper chamber of the middle master cylinder (16).

3. A variable clamping force oil circuit control system for double-action stretch forming equipment according to claim 1, characterized in that: The two-pump confluence control valve group (6) includes a solenoid valve, a first cartridge valve and a shuttle valve. The solenoid valve is connected to the control chamber of the first cartridge valve and is used to open and close the first cartridge valve. The A port of the first cartridge valve is respectively connected to the first pump source control valve group (3), the edge pressure cylinder upper chamber control valve group (8), the edge pressure cylinder lower chamber control valve group (7) and the locking control valve (15); the B port of the first cartridge valve is respectively connected to the second pump source control valve group (4), the middle master cylinder lower chamber control valve group (9), the middle master cylinder upper chamber control valve group (10), the filling valve group (11) and the system pressure control valve group (12); the oil outlet of the shuttle valve is connected to the solenoid valve, and the two oil inlets of the shuttle valve are respectively connected to the A port and the B port of the first cartridge valve.

4. A variable clamping force oil circuit control system for double-action stretch forming equipment according to claim 1, characterized in that: The pressure control valve group (13) of the upper chamber of the edge pressing cylinder and the pressure control valve group (14) of the upper chamber of the middle main cylinder both include a proportional relief valve, a relief valve, a second cartridge valve and a proportional valve filter. The proportional relief valve, the relief valve, the control chamber of the second cartridge valve and the proportional valve filter are connected together, and the proportional valve filter is connected to the oil port of the second cartridge valve.

5. A variable clamping force oil circuit control system for double-action stretch forming equipment according to claim 4, characterized in that: The filtering accuracy of the proportional valve filter is not higher than 10μ.

6. A variable clamping force oil circuit control system for double-action stretch forming equipment according to claim 1, characterized in that: The pressure limit condition of the first pump source control valve group (3) and the second pump source control valve group (4) is not less than 26Mpa; the pressure of the external pressure oil of the pressure cylinder filling valve (21) and the middle main cylinder filling valve (22) is not higher than 5Mpa; the high pressure limit condition of the valve assembly is not less than 26Mpa, and the low pressure limit condition is not higher than 5MPa.

7. A variable clamping force oil circuit control system for double-action stretch forming equipment according to claim 1, characterized in that: The edge pressing slider (19) is connected to a edge pressing cylinder displacement sensor (23), and the middle slider (18) is connected to a middle master cylinder displacement sensor (24).

8. A variable clamping force oil circuit control system for double-action stretch forming equipment according to claim 1, characterized in that: The first pump group (1) and the second pump group (2) are high-pressure servo pump groups.

9. A variable clamping force oil circuit control system for double-action stretch forming equipment according to claim 1, characterized in that: The lower chamber control valve group (7) of the edge pressing cylinder and the lower chamber control valve group (9) of the middle main cylinder both include an oil inlet valve, an oil outlet valve, a support valve and a quick lowering valve; the upper chamber control valve group (8) of the edge pressing cylinder and the upper chamber control valve group (10) of the middle main cylinder both include an oil inlet valve and a pressure maintaining valve.

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