Duplex pump hydraulic system oil circuit and compression molding machine

Abstract

The utility model discloses a kind of duplex pump hydraulic system oil circuit and mould pressing forming machine, it is related to rubber automation production equipment technical field, wherein, duplex pump hydraulic system oil circuit includes duplex pump, including first pump body and second pump body;Pipeline assembly, including first oil inlet pipeline and second oil inlet pipeline;First valve body assembly, including first switch valve and second switch valve, the first switch valve and the first pump body are used to control the on-off of the first oil inlet pipeline and oil return, the second switch valve and the second pump body are used to control the on-off of the second oil return pipeline and oil return;The technical effect of the technical scheme provided by the utility model is that the application can provide one of first pump body and second pump body to supply oil, or the conveying mode that first pump body and second pump body supply oil synchronously, to further improve the application range of hydraulic system oil circuit.

Description

Technical Field

[0001] This utility model relates to the technical field of automated rubber production equipment, and in particular to a double-pump hydraulic system oil circuit and a compression molding machine. Background Technology

[0002] In the current hydraulic systems of the rubber and plastics equipment industry, servo motors paired with single pumps are commonly used for oil supply to provide working pressure during the pressure holding stage on machines such as rubber machines and magnesium alloy injection molding machines. However, existing hydraulic systems have a limited range of applications and low pressure control accuracy, failing to meet user needs. Utility Model Content

[0003] The main purpose of this invention is to propose a hydraulic circuit for a dual-pump hydraulic system and a molding machine, aiming to improve the applicability of the hydraulic system circuit.

[0004] To achieve the above objectives, the present invention proposes a dual-pump hydraulic system circuit for use in a compression molding machine. The dual-pump hydraulic system circuit includes a dual pump, comprising a first pump body and a second pump body; and a piping assembly, including a first inlet pipe, a second inlet pipe, a first return pipe, and a second return pipe. The inlet of the first inlet pipe is connected to the first pump body, and the outlet of the first inlet pipe is used to connect to an external device. The inlet of the second inlet pipe is connected to the second pump body, and the outlet of the second inlet pipe is connected to the first inlet pipe. The inlet of the first return pipe is connected to the... The first oil inlet pipeline is connected, the outlet of the first oil return pipeline is connected to the second oil return pipeline, the inlet of the second oil return pipeline is connected to the second oil inlet pipeline, and the outlet of the second oil return pipeline is used to connect to the oil tank; the first valve body assembly includes a first switching valve and a second switching valve, the first switching valve is located in the first oil return pipeline, the first switching valve and the first pump body are used to control the opening and closing of the first oil inlet pipeline and the return of oil, the second switching valve is located in the second oil return pipeline, the second switching valve and the second pump body are used to control the opening and closing of the second oil return pipeline and the return of oil.

[0005] In one embodiment, the first switching valve includes a first check valve and a first valve body. The first switching valve has a first switching position and a second switching position. When the first switching valve is in the first switching position, the first check valve is connected to the first return oil line to block the first return oil line. When the first switching valve is in the second switching position, the first valve body is connected to the first return oil line to allow the first return oil line to be open. The second switching valve includes a second check valve and a second valve body. The second switching valve has a third switching position and a fourth switching position. When the second switching valve is in the third switching position, the second check valve is connected to the second return oil line to block the second return oil line. When the second switching valve is in the fourth switching position, the second valve body is connected to the second return oil line to allow the second return oil line to be open.

[0006] In one embodiment, the piping assembly further includes a first pressure regulating pipeline and a second pressure regulating pipeline. The first valve body assembly further includes a first relief valve for limiting the pressure of the first oil inlet pipeline. The inlet of the first pressure regulating pipeline is connected to the first oil inlet pipeline, and the outlet of the first pressure regulating pipeline is connected to the first oil return pipeline. The first relief valve is disposed in the first pressure regulating pipeline. The first valve body assembly further includes a second relief valve for limiting the pressure of the second oil inlet pipeline. The inlet of the second pressure regulating pipeline is connected to the second oil inlet pipeline, and the outlet of the second pressure regulating pipeline is connected to the second oil return pipeline. The second relief valve is disposed in the second pressure regulating pipeline.

[0007] In one embodiment, the first switching valve is located between the connection point of the first return oil line and the first pressure regulating line and the first oil inlet line, and the second switching valve is located between the connection point of the second return oil line and the second pressure regulating line and the second oil inlet line.

[0008] In one embodiment, the oil circuit of the dual-pump hydraulic system further includes a cooler, the inlet of which is connected to the outlet of the second return oil line, and the outlet of which is connected to the oil tank.

[0009] In one embodiment, the oil circuit of the dual-pump hydraulic system further includes a second valve body assembly, which is connected to the first oil inlet pipeline. The second valve body assembly is arranged in parallel with the first oil inlet pipeline and is located at one end near the outlet of the first oil inlet pipeline.

[0010] In one embodiment, the second valve body assembly further includes a third switching valve, and the pipeline assembly further includes a third pressure regulating pipeline. The inlet of the third pressure regulating pipeline is connected to the first oil inlet pipeline, and the outlet of the third pressure regulating pipeline is connected to the second oil return pipeline. The third switching valve is disposed in the third pressure regulating pipeline.

[0011] In one embodiment, the second valve body assembly further includes a third relief valve, and the pipeline assembly further includes a fourth pressure regulating pipeline. The inlet of the fourth pressure regulating pipeline is connected to the first oil inlet pipeline, and the outlet of the fourth pressure regulating pipeline is connected to the second oil return pipeline. The fourth pressure regulating pipeline and the third pressure regulating pipeline are arranged in parallel, and the third relief valve is located in the fourth pressure regulating pipeline.

[0012] In one embodiment, the oil circuit of the dual-pump hydraulic system further includes a third check valve and a fourth check valve, wherein the third check valve is located in the first oil inlet line and the fourth check valve is located in the second oil inlet line.

[0013] This utility model also proposes a molding machine, including the oil circuit of the dual-pump hydraulic system as described in any of the above embodiments.

[0014] The technical solution of this utility model employs a first switching valve located in the first return oil pipeline, with the inlet of the first return oil pipeline connected to the first inlet oil pipeline. A second switching valve is located in the second return oil pipeline, with the inlet of the second return oil pipeline connected to the second inlet oil pipeline. Under the operation of the first switching valve, the opening and closing of the first pump body can be controlled. Under the operation of the second switching valve, the opening and closing of the second pump body can be controlled, thereby controlling the on / off state of the first and second return oil pipelines and the return oil. This application can provide a delivery method in which one of the first and second pump bodies supplies oil, or the first and second pump bodies supply oil simultaneously, thus adapting to the needs of different working conditions and improving the applicability of the hydraulic system oil circuit. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the oil circuit of a dual-pump hydraulic system provided by this utility model.

[0017] Explanation of icon numbers:

[0018] 1. Dual pump; 11. First pump body; 12. Second pump body; 2. Piping assembly; 21. First oil inlet pipe; 22. Second oil inlet pipe; 23. First oil return pipe; 24. Second oil return pipe; 25. First pressure regulating pipe; 26. Second pressure regulating pipe; 27. Third pressure regulating pipe; 28. Fourth pressure regulating pipe; 3. First valve body assembly; 31. First switching valve; 311. First check valve; 312. First valve body; 32. Second switching valve; 321. Second check valve; 322. Second valve body; 33. First relief valve; 34. Second relief valve; 4. Cooler; 5. Second valve body assembly; 51. Third switching valve; 52. Third relief valve; 6. Third check valve; 61. Fourth check valve.

[0019] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0021] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0023] This utility model proposes an oil circuit for a dual-pump hydraulic system.

[0024] Please see Figure 1 In one embodiment of this utility model, the dual-pump hydraulic system is applied to a compression molding machine. The dual-pump hydraulic system includes a dual pump 1, a pipeline assembly 2, and a first valve body assembly 3. The dual pump 1 includes a first pump body 11 and a second pump body 12; the pipeline assembly 2 includes a first inlet pipeline 21, a second inlet pipeline 22, a first return pipeline 23, and a second return pipeline 24. The inlet of the first inlet pipeline 21 is connected to the first pump body 11, and the outlet of the first inlet pipeline 21 is used to connect to an external device. The inlet of the second inlet pipeline 22 is connected to the second pump body 12, and the outlet of the second inlet pipeline 22 is connected to the first inlet pipeline 21. The inlet of the first return pipeline 23 is connected to the first inlet pipeline 21, and the outlet of the first return pipeline 23 is connected to the first pump body 12. The second return oil line 24 is connected, the inlet of the second return oil line 24 is connected to the second inlet oil line 22, and the outlet of the second return oil line 24 is used to connect to the oil tank; the first valve body assembly 3 includes a first switching valve 31 and a second switching valve 32. The first switching valve 31 is located in the first return oil line 23. The first switching valve 31 and the first pump body 11 are used to control the opening and closing of the first inlet oil line 21 and the return oil. The second switching valve 32 is located in the second return oil line 24. The second switching valve 32 and the second pump body 12 are used to control the opening and closing of the second return oil line 24 and the return oil.

[0025] The technical solution of this utility model employs a first switching valve 31 located in the first return oil line 23, with the inlet of the first return oil line 23 connected to the first inlet oil line 21. A second switching valve is located in the second return oil line 24, with the inlet of the second return oil line 24 connected to the second inlet oil line 22. Under the operation of the first switching valve, the opening and closing of the first pump body 11 can be controlled. Under the operation of the second switching valve 32, the opening and closing of the second pump body 12 can be controlled, thereby controlling the on / off state of the first return oil line 23 and the second return oil line 24, as well as the return oil. This application can provide a delivery method in which one of the first pump body 11 and the second pump body 12 supplies oil, or the first pump body 11 and the second pump body 12 supply oil simultaneously, thereby adapting to the needs of different working conditions and improving the applicability of the hydraulic system oil circuit.

[0026] In this embodiment, the present application is applied to supply oil to the hydraulic cylinder in a compression molding machine. The compression molding machine may include an oil tank. The oil inlet of the dual pump 1 is connected to the oil tank, and the oil return port of the dual pump 1 is connected to the oil tank through a second oil return pipeline 24. The oil outlet of the dual pump 1 is connected to the hydraulic cylinder through a first oil inlet pipeline 21 and an external delivery pipeline (not shown). The inlet of the first oil inlet pipeline 21 is connected to the first pump body 11, the inlet of the second oil inlet pipeline 22 is connected to the second pump body 12, and the outlet of the second oil inlet pipeline 22 is connected to the end of the first oil inlet pipeline 21 away from the first pump body 11, so that the first oil inlet pipeline 21 and the second oil inlet pipeline 22 are two independent oil inlet circuits. The hydraulic oil in the first oil inlet pipeline 21 and the second oil inlet pipeline 22 can be collected in the first oil inlet pipeline 21 and delivered outward, making it more convenient for users to adjust the oil supply efficiency of the first oil inlet pipeline 21 and the second oil inlet pipeline 22 according to the needs of the working conditions, thus reducing the operating cost. To facilitate user control of the opening and closing of the first oil inlet pipe 21 and the second oil inlet pipe 22, this application connects the first switching valve 31 to the first return oil pipe 23 and the second switching valve 32 to the second return oil pipe 24. The operation of the first switching valve 31 and the second switching valve 32 controls the opening and closing of the first pump body 11 and the second pump body 12, thereby adjusting the oil supply flow rate of the hydraulic system. This allows for the use of either the first pump body 11 or the second pump body 12, or both, for oil supply depending on different operating conditions, thus expanding the applicability of this application. To further reduce the operating cost, this application connects one end of the first return oil pipe 23 to the first oil inlet pipe 21 and the other end of the first return oil pipe 23 to the second return oil pipe 24. This allows a portion of the hydraulic oil from the first oil inlet pipe 21 to be transported to the oil tank through the first return oil pipe 23 and the second return oil pipe 24, making the hydraulic system more energy-efficient. This application utilizes a second return oil line 24, with one end connected to the second inlet oil line 22 and the other end connected to the oil tank. This allows a portion of the hydraulic oil from the second inlet oil line 22 to be transported to the oil tank via the second return oil line 24, thus saving energy consumption in the hydraulic system. Under the operation of the first switching valve 31 or the second switching valve 32, this application allows a single pump to operate within the hydraulic system. This reduces the overall hydraulic oil displacement, improving pressure control accuracy and further reducing pressure fluctuations, ultimately ensuring and improving the quality of products produced by the machine.

[0027] like Figure 1As shown, in one embodiment, the first switching valve 31 includes a first check valve 311 and a first valve body 312. The first switching valve 31 has a first switching position and a second switching position. When the first switching valve 31 is in the first switching position, the first check valve 311 is connected to the first return oil line 23 to block the first return oil line 23. When the first switching valve 31 is in the second switching position, the first valve body 312 is connected to the first return oil line 23 to allow the first return oil line 23 to be open. The second switching valve 32 includes a second check valve 321 and a second valve body 322. The second switching valve 32 has a third switching position and a fourth switching position. When the second switching valve 32 is in the third switching position, the second check valve 321 is connected to the second return oil line 24 to block the second return oil line 24. When the second switching valve 32 is in the fourth switching position, the second valve body 322 is connected to the second return oil line 24 to allow the second return oil line 24 to be open.

[0028] In this embodiment, the application further includes a control component (not shown). The control component may include electronic components such as a circuit board or controller. The control component is electrically connected to the first switching valve 31 and the second switching valve 32. The control component can control the first switching valve 31 to switch between a first switching position and a second switching position, and the control component can control the second switching valve 32 to switch between a third switching position and a fourth switching position, thereby better controlling the opening and closing of the first oil inlet pipe 21 and the second oil inlet pipe 22, as well as the return oil. To facilitate the opening and closing of the first pump body 11, the application controls the first switching valve 31 to switch to the first switching position through the control component. The first one-way valve 311 is connected to the first return oil pipe 23. The liquid flow direction of the first one-way valve 311 is opposite to the liquid flow direction of the first return oil pipe 23, so that the first return oil pipe 23 is blocked, cutting off the return oil of the first pump body 11 and the first oil inlet pipe 21. The first pump body 11 stops working, and the second pump body 12 operates independently. This application controls the first switching valve 31 to switch to the second switching position via a control component. The first valve body 312 is connected to the first return oil line 23, allowing the first return oil line 23 to be open. Part of the hydraulic oil on the first inlet oil line 21 can be transported to the oil tank through the first return oil line 23, and the first pump body 11 operates normally. To more conveniently control the opening and closing of the second pump body 12, this application controls the second switching valve 32 to switch to the third switching position via a control component. The second check valve 321 is connected to the second return oil line 24. The liquid flow direction of the second check valve 321 is opposite to the liquid flow direction of the second return oil line 24, thus blocking the second return oil line 24, cutting off the return oil to the second pump body 12 and the second inlet oil line 22. The second pump body 12 stops working, and the first pump body 11 operates independently. This application controls the second switching valve 32 to switch to the fourth switching position through the control component. The second valve body 322 is connected to the second return oil line 24 so that the second return oil line 24 is open. Part of the hydraulic oil on the second inlet oil line 22 can be transported to the oil tank through the second return oil line 24, and the second pump body 12 operates normally.

[0029] like Figure 1 As shown, in one embodiment, the pipeline assembly 2 further includes a first pressure regulating pipeline 25 and a second pressure regulating pipeline 26, and the first valve body assembly 3 further includes a first relief valve 33 for limiting the pressure of the first oil inlet pipeline 21. The inlet of the first pressure regulating pipeline 25 is connected to the first oil inlet pipeline 21, and the outlet of the first pressure regulating pipeline 25 is connected to the first oil return pipeline 23. The first relief valve 33 is disposed in the first pressure regulating pipeline 25.

[0030] The first valve body assembly 3 further includes a second relief valve 34 for limiting the pressure of the second oil inlet line 22. The inlet of the second pressure regulating line 26 is connected to the second oil inlet line 22, and the outlet of the second pressure regulating line 26 is connected to the second return line 24. The second relief valve 34 is disposed in the second pressure regulating line 26.

[0031] In this embodiment, to improve the safety of the hydraulic system, this application employs a first relief valve 33 and a second relief valve 34 to limit the maximum pressure of the first inlet pipe 21 and the second inlet pipe 22, respectively. When the hydraulic oil pressure in the first inlet pipe 21 exceeds the preset pressure of the first relief valve 33, the control component opens the first relief valve 33, and the hydraulic oil in the first inlet pipe 21 is transported to the first return pipe 23 through the first pressure regulating pipe 25, thereby reducing the hydraulic oil pressure in the first inlet pipe 21. When the hydraulic oil pressure in the second inlet pipe 22 exceeds the preset pressure of the second relief valve 34, the control component opens the second relief valve 34, and the hydraulic oil in the second inlet pipe 22 is transported to the second return pipe 24 through the second pressure regulating pipe 26, thereby reducing the hydraulic oil pressure in the second inlet pipe 22. To facilitate the first relief valve 33 and the second relief valve 34 in limiting the pressure of the first oil inlet line 21 and the second oil inlet line 22 respectively, the first relief valve 33 can be located between the connection point of the first pressure regulating line 25 and the first return line 23 and the first oil inlet line 21, and the second relief valve 34 can be located between the connection point of the second pressure regulating line 26 and the second return line 24 and the second oil inlet line 22.

[0032] like Figure 1 As shown, in one embodiment, the first switching valve 31 is located between the connection point of the first return oil line 23 and the first pressure regulating line 25 and the first oil inlet line 21, and the second switching valve 32 is located between the connection point of the second return oil line 24 and the second pressure regulating line 26 and the second oil inlet line 22.

[0033] In this embodiment, to facilitate the control of the opening and closing of the first pump body 11 by the first switching valve 31, the first switching valve 31 is located between the connection point of the first return oil line 23 and the first pressure regulating line 25 and the first inlet oil line 21. The hydraulic oil in the first inlet oil line 21 can return through the first return oil line 23. The first switching valve 31 can switch to the first switching position or the second switching position to control the opening or closing of the first return oil line 23, thereby controlling the opening and closing of the first pump body 11. To facilitate the control of the opening and closing of the second pump body 12 by the second switching valve 32, the second switching valve 32 is located between the connection point of the second return oil line 24 and the second pressure regulating line 26 and the second inlet oil line 22. The hydraulic oil in the second inlet oil line 22 can return through the second return oil line 24. The second switching valve 32 can switch to the third switching position or the fourth switching position to control the opening or closing of the second return oil line 24, thereby controlling the opening and closing of the second pump body 12. In one embodiment, the control component can control the opening or closing of the first pump body 11 according to the opening or closing of the first return oil line 23, and the control component can control the opening or closing of the second pump body 12 according to the opening or closing of the second return oil line 24.

[0034] like Figure 1 As shown, in one embodiment, the oil circuit of the dual-pump hydraulic system further includes a cooler 4, the inlet of which is connected to the outlet of the second return oil line 24, and the outlet of which is connected to the oil tank.

[0035] In this embodiment, to further reduce the cost of using this application, a cooler 4 is used to cool the hydraulic oil transported by the first return oil line 23 and the second return oil line 24. The hydraulic oil in the first return oil line 23 converges into the second return oil line 24, so that the hydraulic oil in both lines is cooled by the cooler 4 before being transported to the oil tank, thereby improving the cooling efficiency of the hydraulic oil and ensuring the normal operating temperature of this application. In one embodiment, the cooler 4 can simultaneously filter impurities in the hydraulic oil, thereby improving the utilization rate of the hydraulic oil.

[0036] like Figure 1 As shown, in one embodiment, the oil circuit of the dual-pump hydraulic system further includes a second valve body assembly 5, which is connected to the first oil inlet pipe 21. The second valve body assembly 5 is arranged in parallel with the first oil inlet pipe 21, and the second valve body assembly 5 is located at one end near the outlet of the first oil inlet pipe 21.

[0037] In this embodiment, when the first pump body 11 and the second pump body 12 operate synchronously to supply oil, the hydraulic oil pressure in the first inlet pipe 21 will increase. To avoid excessive pressure on the first inlet pipe 21 under the synchronous operation of the dual pumps 1, this application uses a second valve body assembly 5, one end of which is connected to the first inlet pipe 21, and the other end of which is connected to the second return pipe 24 through the pipe assembly 2. The second valve body assembly 5 is used to limit the pressure of the hydraulic oil in the first inlet pipe 21 and to supply hydraulic oil for return in the first inlet pipe 21. The second valve body assembly 5 is located near the outlet of the first inlet pipe 21, so that the second valve body assembly 5 can cooperate with the first relief valve 33 to limit the pressure at different positions of the first inlet pipe 21, thereby improving the safety of the hydraulic system.

[0038] like Figure 1 As shown, in one embodiment, the second valve body assembly 5 further includes a third switching valve 51, and the pipeline assembly 2 further includes a third pressure regulating pipeline 27. The inlet of the third pressure regulating pipeline 27 is connected to the first oil inlet pipeline 21, and the outlet of the third pressure regulating pipeline 27 is connected to the second oil return pipeline 24. The third switching valve 51 is disposed on the third pressure regulating pipeline 27.

[0039] In this embodiment, to improve the safety of the hydraulic system, a third switching valve 51 is used to unload the pressure of the hydraulic system. When the hydraulic oil pressure in the first inlet pipe 21 exceeds the preset pressure of the third switching valve 51, the control component opens the third switching valve 51, and the hydraulic oil in the first inlet pipe 21 is transported to the second return pipe 24 through the third pressure regulating pipe 27, thereby reducing the hydraulic oil pressure in the first inlet pipe 21. In one embodiment, the third switching valve 51 can be configured as a single-head solenoid switching valve or a pressure relief solenoid valve, etc.

[0040] like Figure 1 As shown, in one embodiment, the second valve body assembly 5 further includes a third relief valve 52, and the pipeline assembly 2 further includes a fourth pressure regulating pipeline 28. The inlet of the fourth pressure regulating pipeline 28 is connected to the first oil inlet pipeline 21, and the outlet of the fourth pressure regulating pipeline 28 is connected to the second oil return pipeline 24. The fourth pressure regulating pipeline 28 and the third pressure regulating pipeline 27 are arranged in parallel, and the third relief valve 52 is located in the fourth pressure regulating pipeline 28.

[0041] In this embodiment, to improve the safety of the hydraulic system, this application employs a third relief valve 52 to limit the maximum pressure of the first inlet pipeline 21. When the hydraulic oil pressure in the first inlet pipeline 21 exceeds the preset pressure of the third relief valve 52, the control component opens the third relief valve 52, and the hydraulic oil in the first inlet pipeline 21 is transported to the second return pipeline 24 through the fourth pressure regulating pipeline 28, thereby reducing the hydraulic oil pressure in the first inlet pipeline 21. The first relief valve 33 can limit the pressure generated on the first inlet pipeline 21 when the first pump body 11 draws hydraulic oil to the first inlet pipeline 21, and the third relief valve 52 can limit the pressure generated on the first inlet pipeline 21 when the first pump body 11 and the second pump body 12 respectively converge hydraulic oil into the first inlet pipeline 21, so that the hydraulic system can supply oil more stably.

[0042] like Figure 1 As shown, in one embodiment, the oil circuit of the dual-pump hydraulic system further includes a third check valve 6 and a fourth check valve 61. The third check valve 6 is located in the first oil inlet line 21, and the fourth check valve 61 is located in the second oil inlet line 22.

[0043] In this embodiment, to avoid mutual interference when the first pump body 11 draws hydraulic oil to the first inlet pipe 21 and the second pump body 12 draws hydraulic oil to the second inlet pipe 22, this application uses a third check valve 6 in the first inlet pipe 21 and a fourth check valve 61 in the second inlet pipe 22. This ensures that the first inlet pipe 21 and the second inlet pipe 22 operate independently when the dual pump 1 is pumping oil, and does not affect the subsequent convergence of hydraulic oil in the first inlet pipe 21 and the outward delivery of hydraulic oil. The third check valve 6 can be used to allow the hydraulic oil in the first inlet pipe 21 to flow unidirectionally from the inlet to the outlet of the first inlet pipe 21, and the fourth check valve 61 can be used to allow the hydraulic oil in the second inlet pipe 22 to flow unidirectionally from the inlet to the outlet of the second inlet pipe 22.

[0044] This utility model also proposes a compression molding machine, which includes a dual-pump hydraulic system oil circuit. The specific structure of the dual-pump hydraulic system oil circuit is as described in the above embodiments. Since this compression molding machine adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0045] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A hydraulic circuit for a dual-pump hydraulic system, applied to a compression molding machine, characterized in that, The oil circuit of the dual-pump hydraulic system includes: A tandem pump, comprising a first pump body and a second pump body; The piping assembly includes a first oil inlet pipe, a second oil inlet pipe, a first oil return pipe, and a second oil return pipe. The inlet of the first oil inlet pipe is connected to the first pump body, and the outlet of the first oil inlet pipe is used to connect to an external device. The inlet of the second oil inlet pipe is connected to the second pump body, and the outlet of the second oil inlet pipe is connected to the first oil inlet pipe. The inlet of the first oil return pipe is connected to the first oil inlet pipe, and the outlet of the first oil return pipe is connected to the second oil return pipe. The inlet of the second oil return pipe is connected to the second oil inlet pipe, and the outlet of the second oil return pipe is used to connect to an oil tank. The first valve body assembly includes a first switching valve and a second switching valve. The first switching valve is located in the first return oil line. The first switching valve and the first pump body are used to control the opening and closing of the first inlet oil line and the return oil. The second switching valve is located in the second return oil line. The second switching valve and the second pump body are used to control the opening and closing of the second return oil line and the return oil.

2. The hydraulic circuit of the dual-pump hydraulic system as described in claim 1, characterized in that, The first switching valve includes a first check valve and a first valve body. The first switching valve has a first switching position and a second switching position. When the first switching valve is in the first switching position, the first check valve is connected to the first return oil line to block the first return oil line. When the first switching valve is in the second switching position, the first valve body is connected to the first return oil line to allow the first return oil line to be open. The second switching valve includes a second check valve and a second valve body. The second switching valve has a third switching position and a fourth switching position. When the second switching valve is in the third switching position, the second check valve is connected to the second return oil line to block the second return oil line. When the second switching valve is in the fourth switching position, the second valve body is connected to the second return oil line to allow the second return oil line to be open.

3. The hydraulic circuit of the dual-pump hydraulic system as described in claim 1, characterized in that, The pipeline assembly further includes a first pressure regulating pipeline and a second pressure regulating pipeline. The first valve body assembly further includes a first relief valve for limiting the pressure of the first oil inlet pipeline. The inlet of the first pressure regulating pipeline is connected to the first oil inlet pipeline, and the outlet of the first pressure regulating pipeline is connected to the first oil return pipeline. The first relief valve is located in the first pressure regulating pipeline. The first valve body assembly further includes a second relief valve for limiting the pressure of the second oil inlet line. The inlet of the second pressure regulating line is connected to the second oil inlet line, and the outlet of the second pressure regulating line is connected to the second oil return line. The second relief valve is located in the second pressure regulating line.

4. The hydraulic circuit of the dual-pump hydraulic system as described in claim 3, characterized in that, The first switching valve is located between the connection point of the first return oil line and the first pressure regulating line and the first inlet oil line, and the second switching valve is located between the connection point of the second return oil line and the second pressure regulating line and the second inlet oil line.

5. The hydraulic circuit of the dual-pump hydraulic system as described in claim 1, characterized in that, The oil circuit of the dual-pump hydraulic system also includes a cooler, the inlet of which is connected to the outlet of the second return oil line, and the outlet of which is connected to the oil tank.

6. The hydraulic circuit of the dual-pump hydraulic system as described in claim 1, characterized in that, The oil circuit of the dual-pump hydraulic system also includes a second valve body assembly, which is connected to the first oil inlet pipeline. The second valve body assembly is arranged in parallel with the first oil inlet pipeline and is located at one end near the outlet of the first oil inlet pipeline.

7. The hydraulic circuit of the dual-pump hydraulic system as described in claim 6, characterized in that, The second valve body assembly further includes a third switching valve, and the pipeline assembly further includes a third pressure regulating pipeline. The inlet of the third pressure regulating pipeline is connected to the first oil inlet pipeline, and the outlet of the third pressure regulating pipeline is connected to the second oil return pipeline. The third switching valve is located in the third pressure regulating pipeline.

8. The hydraulic circuit of the dual-pump hydraulic system as described in claim 6, characterized in that, The second valve body assembly further includes a third relief valve, and the pipeline assembly further includes a fourth pressure regulating pipeline. The inlet of the fourth pressure regulating pipeline is connected to the first oil inlet pipeline, and the outlet of the fourth pressure regulating pipeline is connected to the second oil return pipeline. The fourth pressure regulating pipeline and the third pressure regulating pipeline are arranged in parallel, and the third relief valve is located in the fourth pressure regulating pipeline.

9. The hydraulic circuit of the dual-pump hydraulic system as described in claim 1, characterized in that, The oil circuit of the dual-pump hydraulic system also includes a third check valve and a fourth check valve. The third check valve is located in the first oil inlet line, and the fourth check valve is located in the second oil inlet line.

10. A compression molding machine, characterized in that, Includes the oil circuit of the dual-pump hydraulic system as described in any one of claims 1 to 9.

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