Hydraulic quick and slow conversion system and method for controlling the lowering of a hydraulic press slide

Abstract

The application relates to a hydraulic quick-slow conversion system and method for controlling the downward pressing of a hydraulic machine slider, wherein the system comprises a first oil path, a second oil path, a hydraulic machine slider and a return cylinder, the first oil path is connected with an upper cavity of the return cylinder, the second oil path is connected with a lower cavity of the return cylinder, a first machine valve for controlling the on-off of the second oil path is arranged on the second oil path, the first machine valve is connected with a first electromagnetic valve, the hydraulic machine slider is fixedly connected with the return cylinder, a second machine valve and a third machine valve for controlling the return speed are arranged on the second oil path, the second machine valve is located between the first machine valve and the third machine valve, the oil inlet of the second machine valve and the oil inlet of the third machine valve are communicated with the second oil path, the oil outlet of the second machine valve and the oil outlet of the third machine valve are connected with a return tank, the second machine valve is connected with a second electromagnetic valve, and the third machine valve is connected with a third electromagnetic valve. The application has the effect of controlling the downward pressing speed of the hydraulic machine slider.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic control, in particular to a hydraulic fast / slow speed conversion system and method for controlling the downward movement of a hydraulic press slide. BACKGROUND

[0002] A hydraulic press is a machine that uses liquid as a working medium to transfer energy to achieve various processes according to Pascal's principle. A hydraulic press generally consists of a machine (main machine), a power system, and a hydraulic control system. It is often used in pressing processes and pressing forming processes, such as forging, stamping, cold extrusion, straightening, bending, flanging, sheet drawing, powder metallurgy, and press fitting. The hydraulic press is classified into valve hydraulic press, liquid hydraulic press, and engineering hydraulic press. In addition, the main function of the hydraulic press slide is to connect with the hydraulic press main oil cylinder piston rod to transfer the pressure of the hydraulic press.

[0003] In related technologies, in order to make the hydraulic press slide quickly descend or return, and improve the efficiency of the hydraulic press descending and closing the mold, the upper cavity and the lower cavity in the return cylinder connected with the hydraulic press slide are selected to be injected with oil by an oil pump.

[0004] According to the related technologies in the above, the inventors believe that the following defects exist: Although injecting oil into the upper cavity and the lower cavity in the return cylinder can speed up the descent of the hydraulic press slide, the speed of the large-tonnage hydraulic press slide is too fast when it quickly descends and closes the mold, which can cause a large pressure impact on the mold and the processing medium, resulting in damage to the mold or the processing medium. SUMMARY

[0005] In order to control the descent speed of the hydraulic press slide and reduce the pressure impact of the hydraulic press slide on the mold and the processing medium, the present application provides a hydraulic fast / slow speed conversion system for controlling the downward movement of a hydraulic press slide.

[0006] In a first aspect of the present application, a hydraulic fast / slow speed conversion system for controlling the downward movement of a hydraulic press slide is provided, which specifically includes a first oil path, a second oil path, a hydraulic press slide, and a return cylinder. The return cylinder includes an upper cavity and a lower cavity. The first oil path is connected with the upper cavity, and the second oil path is connected with the lower cavity. A first machine valve for controlling the on / off of the second oil path is arranged on the second oil path. The first machine valve is connected with a first electromagnetic valve. The hydraulic press slide is fixedly connected with the return cylinder. A second machine valve and a third machine valve for controlling the return speed are arranged on the second oil path. The second machine valve is located between the first machine valve and the third machine valve. The oil inlet of the second machine valve and the oil inlet of the third machine valve are both in communication with the second oil path. The oil outlet of the second machine valve and the oil outlet of the third machine valve are connected with a return tank. The second machine valve is connected with a second electromagnetic valve, and the third machine valve is connected with a third electromagnetic valve.

[0007] By adopting the above technical solution, during the downward movement of the hydraulic press slide, the first, second, and third solenoid valves remain open. Oil is injected into the upper chamber of the return cylinder through the first oil circuit, and the oil pressure acts on the upper chamber of the return cylinder. Oil in the lower chamber flows rapidly into the return oil tank through the outlets of the first, second, and third solenoid valves, thus causing the hydraulic press slide to descend rapidly. When the downward speed of the hydraulic press slide is too fast, the operator can control the opening and closing of the second and third solenoid valves, thereby reducing the amount of oil output from the second oil circuit and controlling the downward speed of the hydraulic press slide.

[0008] Optionally, the system further includes an intelligent device, wherein the first solenoid valve, the second solenoid valve, and the third solenoid valve are all coupled to the intelligent device, and the intelligent device is coupled to a rangefinder. The intelligent device includes:

[0009] The downhill distance acquisition module is used to acquire the downhill distance value of the hydraulic press slider measured by the rangefinder;

[0010] The distance comparison module is used to compare the downlink distance value with a preset distance value;

[0011] The solenoid valve control module is used to close the second solenoid valve and keep the first and third solenoid valves open when the downward distance value is greater than or equal to the preset distance value.

[0012] By adopting the above technical solution, when the hydraulic press slide descends, the distance comparison module compares the descending distance value obtained by the descending distance acquisition module with a preset distance value. If the descending distance value is greater than or equal to the preset distance value, it indicates that the distance the hydraulic press slide has descended rapidly exceeds a critical value. If the speed is not reduced, the hydraulic press slide will cause a significant impact on the mold and processing medium. Then, the second solenoid valve is closed, while the first and third solenoid valves remain open, allowing oil pressure to flow slowly back to the oil tank through the first and third solenoid valves. This effectively controls the descending speed of the hydraulic press slide and reduces the pressure impact on the mold and processing medium.

[0013] Optionally, the second valve is a fast-flow valve, and the third valve is a slow-flow valve.

[0014] By adopting the above technical solution, the second and third valves are flow-adjustable valves. The second valve is a high-flow-rate valve, allowing oil to flow quickly. The third valve is a low-flow-rate valve, allowing oil to flow slowly. When the hydraulic press slide descends too quickly, the second valve can be closed, allowing oil in the second oil circuit to flow back to the oil tank through the outlet of the third valve, thus significantly reducing the slide speed. Conversely, when the slide descends slightly too quickly, the third valve can be closed, resulting in a smaller reduction in slide speed. Therefore, by adjusting the second and third valves, the oil inlet and outlet flow rates can be controlled, effectively regulating the downward speed of the hydraulic press slide.

[0015] Optionally, the intelligent device is coupled to a speed sensor, and the intelligent device further includes:

[0016] The downward speed acquisition module is used to acquire the downward speed value of the hydraulic press slider as measured by the speed sensor;

[0017] A speed comparison module is used to compare the downlink speed value with a speed threshold.

[0018] The preset distance reduction module is used to reduce the preset distance value to a first threshold when the downlink speed value is greater than the speed threshold.

[0019] By adopting the above technical solution, the speed sensor transmits the real-time measured downward speed value of the hydraulic press slide to the downward speed acquisition module. The speed comparison module compares the downward speed value with a speed threshold. If the downward speed value is greater than the speed threshold, it indicates that the initial downward speed of the hydraulic press slide is too fast. Further deceleration of the hydraulic press slide beyond the original preset distance may cause a large pressure impact on the mold and processing medium. The preset distance reduction module is then activated, reducing the preset distance value to the preset first threshold, thereby causing the hydraulic press slide to enter the deceleration phase earlier.

[0020] Optionally, the smart device further includes:

[0021] The preset distance adjustment module is used to increase the preset distance value to a second threshold when the downlink speed value is less than the speed threshold.

[0022] By adopting the above technical solution, if the downward speed of the hydraulic press slide is less than the speed threshold, it indicates that the initial downward speed of the hydraulic press slide is slightly slower than the normal speed threshold. Further slowing down the slide beyond the original preset distance will result in lower mold-closing efficiency. The preset distance adjustment module, when activated, increases the preset distance to the second preset threshold, extending the rapid downward time of the hydraulic press slide. This improves the mold-closing efficiency of the hydraulic press while ensuring that it does not cause excessive pressure impact on the mold and processing medium.

[0023] Optionally, the smart device is coupled to a display screen, and the smart device includes:

[0024] The speed reduction calculation module is used to calculate the speed reduction based on the downlink speed value obtained by the downlink speed acquisition module within a preset time when the downlink distance value is greater than or equal to the preset distance value.

[0025] A reduction comparison module is used to compare the speed reduction with a preset reduction threshold.

[0026] The fault display module is used to generate fault information and display it on the display screen when the speed drop exceeds the drop threshold.

[0027] By adopting the above technical solution, when the downward speed of the hydraulic press slide is greater than or equal to a preset distance, the second solenoid valve closes, while the first and third solenoid valves remain open. This reduces the speed at which oil pressure flows back to the oil tank, thus lowering the downward speed of the hydraulic press slide. At this time, the downward speed acquisition module obtains different downward speed values ​​of the hydraulic press slide within a preset time period. The speed reduction calculation module calculates the speed reduction within the preset time period based on these different downward speed values. Then, the speed reduction comparison module compares the speed reduction with a speed reduction threshold. If the speed reduction is greater than the threshold, it indicates that closing the second solenoid valve and disconnecting the corresponding second mechanical valve has not effectively reduced the downward speed of the hydraulic press slide, suggesting a possible malfunction in the second solenoid valve, preventing it from disconnecting. Finally, the fault display module activates, generating fault information and displaying it on the screen, prompting personnel to perform timely maintenance.

[0028] Optionally, the return cylinder includes an oil distribution pipe that connects the upper cavity and the lower cavity. A fourth solenoid valve is provided at one end of the oil distribution pipe near the upper cavity, and the fourth solenoid valve is coupled to the intelligent device.

[0029] By adopting the above technical solution, hydraulic oil enters from the upper chamber of the return cylinder. The oil distribution pipe diverts a portion of the oil in the upper cylinder to the lower chamber, thus reducing the oil pressure in the upper chamber. This reduces the hydraulic pressure, decreasing the driving force of the return cylinder on the hydraulic press slide and decreasing the downward speed. Furthermore, the intelligent device can control the opening and closing of the fourth solenoid valve to adjust the hydraulic pressure in the return cylinder, thereby controlling the downward speed of the hydraulic press slide.

[0030] Optionally, the smart device further includes:

[0031] The channel control module, coupled to the fourth solenoid valve, is used to control the fourth solenoid valve to open when the speed drop exceeds the drop threshold.

[0032] By adopting the above technical solution, when the hydraulic press slide descends a preset distance, the second solenoid valve is closed. If the speed reduction of the hydraulic press slide within a preset time is greater than the reduction threshold, it indicates that the effect of reducing the speed of the hydraulic press slide is poor. Then, the channel control module starts working and opens the fourth solenoid valve, which reduces the hydraulic pressure, thereby reducing the speed of the hydraulic press slide and preventing excessive impact pressure on the mold and processing medium.

[0033] The second aspect of this application provides a method for controlling the downward pressure of a hydraulic press slide by switching between fast and slow hydraulic speeds, specifically including:

[0034] Obtain the downward distance of the hydraulic press slide measured by a rangefinder;

[0035] Compare the downlink distance value with the preset distance value;

[0036] If the downward distance value is greater than or equal to the preset distance value, the second solenoid valve is closed, while the first and third solenoid valves remain open.

[0037] By adopting the above technical solution, the downward distance value of the hydraulic press slider measured by the rangefinder is obtained, that is, the distance that the hydraulic press slider slides during the rapid downward process. The downward distance value is compared with the preset distance value. If the downward distance value is greater than or equal to the preset distance value, it means that the hydraulic press slider has descended to the predetermined position. Then, the downward speed of the hydraulic press slider needs to be controlled. The second solenoid valve of the first, second and third solenoid valves that was previously kept open is closed, so that the oil pressure flows slowly back to the oil tank through the first and third solenoid valves in the second oil circuit, thereby reducing the downward speed of the hydraulic press slider and reducing the pressure impact of the hydraulic press slider on the mold and processing medium.

[0038] In summary, this application includes at least one of the following beneficial technical effects:

[0039] 1. During the downward movement of the hydraulic press slide block, the first, second, and third solenoid valves remain open. Oil is injected into the upper chamber of the return cylinder through the first oil circuit, and the oil pressure acts on the upper chamber of the return cylinder. The oil in the lower chamber flows rapidly into the return oil tank through the outlets of the first, second, and third solenoid valves, thus causing the hydraulic press slide block to move downwards quickly. When the downward speed of the hydraulic press slide block is too fast, the operator can adjust the opening and closing of the second and third solenoid valves to reduce the rate at which oil flows from the lower chamber into the return oil tank, thereby controlling the downward speed of the hydraulic press slide block.

[0040] 2. The speed sensor transmits the real-time measured downward speed of the hydraulic press slide to the downward speed acquisition module. The speed comparison module compares the downward speed value with a speed threshold. If the downward speed value is greater than the speed threshold, it indicates that the initial downward speed of the hydraulic press slide is too fast. Further deceleration after the original preset distance may cause significant pressure impact on the mold and processing medium. The preset distance reduction module then activates, reducing the preset distance value to the preset first threshold, thus causing the hydraulic press slide to enter the deceleration phase earlier. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of a hydraulic fast / slow speed switching system for controlling the downward pressure of a hydraulic press slider, provided in an embodiment of this application.

[0042] Figure 2 This is a schematic diagram of the architecture of a hydraulic fast-slow speed switching system for controlling the downward pressure of a hydraulic press slider, provided in an embodiment of this application.

[0043] Figure 3 This is a schematic flowchart of a hydraulic fast / slow speed switching method for controlling the downward pressure of a hydraulic press slider provided in an embodiment of this application;

[0044] Figure 4 This is a schematic diagram of another hydraulic fast / slow speed switching system for controlling the downward pressure of a hydraulic press slider provided in an embodiment of this application.

[0045] Explanation of reference numerals in the attached figures:

[0046] 1. First oil circuit; 2. Second oil circuit; 21. First mechanical valve; 22. First solenoid valve; 23. Second mechanical valve; 24. Second solenoid valve; 25. Third mechanical valve; 26. Third solenoid valve; 3. Hydraulic press slide block; 4. Return cylinder; 41. Upper cavity; 42. Lower cavity; 43. Oil distribution pipe; 44. Fourth solenoid valve; 45. Upper cylinder body; 46. Lower cylinder body; 47. Return piston; 471. Upper push rod; 472. Lower push rod; 473. Piston block; 5. Intelligent device; 51. Downward distance acquisition module; 52. Distance comparison module; 53. Solenoid valve control module; 54. Downward speed acquisition module; 55. Speed ​​comparison module; 56. Preset distance reduction module; 57. Preset distance increase module; 58. Speed ​​reduction calculation module; 59. Speed ​​reduction comparison module; 510. Fault display module; 511. Channel control module; 6. Return oil tank; 7. Rangefinder; 8. Speed ​​sensor; 9. Display screen. Detailed Implementation

[0047] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0048] In the description of the embodiments in this application, words such as "illustrative," "for example," or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "illustrative," "for example," or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Rather, the use of words such as "illustrative," "for example," or "for example" is intended to present the relevant concepts in a specific manner.

[0049] In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, B existing alone, or A and B existing simultaneously. Furthermore, unless otherwise stated, the term "multiple" means two or more. For example, multiple systems refer to two or more systems, and multiple screen terminals refer to two or more screen terminals. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. The terms "comprising," "including," "having," and their variations all mean "including but not limited to," unless otherwise specifically emphasized.

[0050] The following is in conjunction with the appendix Figures 1-4 This application will be described in further detail.

[0051] This application discloses a hydraulic fast / slow speed switching system for controlling the downward pressure of a hydraulic press slider.

[0052] See Figure 1 and Figure 2A hydraulic fast / slow speed switching system for controlling the downward pressure of a hydraulic press slide includes a first oil circuit 1, a second oil circuit 2, a hydraulic press slide 3, and a return cylinder 4. The return cylinder 4 includes an upper cavity 41 and a lower cavity 42. The first oil circuit 1 is connected to the upper cavity 41, and the second oil circuit 2 is connected to the lower cavity 42. A first valve 21 for controlling the on / off state of the second oil circuit 2 is provided on the second oil circuit 2. The first valve 21 is connected to a first solenoid valve 22. The hydraulic press slide 3 is fixedly connected to the return cylinder 4. A second valve 23 and a third valve 25 for controlling the return oil speed are provided on the second oil circuit 2. The second valve 23 is located between the first valve 21 and the third valve 25. The oil inlet of the second valve 23 and the oil inlet of the third valve 25 are both connected to the second oil circuit 2. The oil outlets of the second valve 23 and the third valve 25 are connected to a return oil tank 6. The second valve 23 is connected to a second solenoid valve 24, and the third valve 25 is connected to a third solenoid valve 26. The first solenoid valve 22, the second solenoid valve 24, and the third solenoid valve 26 are all coupled to the intelligent device 5. The intelligent device 5 is coupled to a rangefinder 7, a speed sensor 8, and a display screen 9. Among them, the second solenoid valve 23 is a fast-flow solenoid valve, and the third solenoid valve 25 is a slow-flow solenoid valve.

[0053] The intelligent device 5 includes: a downlink distance acquisition module 51, a distance comparison module 52, a solenoid valve control module 53, a downlink speed acquisition module 54, a speed comparison module 55, a preset distance reduction module 56, a preset distance increase module 57, a speed reduction calculation module 58, a speed reduction comparison module 59, a fault display module 510, and a channel control module 511. Among these, the rangefinder 7 is used to measure the downlink distance of the hydraulic press slider 3, the speed sensor 8 is used to measure the downlink speed of the hydraulic press slider 3, and the display screen 9 is used to display fault information of the hydraulic press. It should be noted that in this embodiment, the intelligent device 5 can be a computer, and all the above modules are program modules within the intelligent device 5.

[0054] The downward distance acquisition module 51 is used to acquire the downward distance value of the hydraulic press slider 3 measured by the rangefinder 7; the distance comparison module 52 is used to compare the downward distance value with the preset distance value; the solenoid valve control module 53 is used to close the second solenoid valve 24 and keep the first solenoid valve 22 and the third solenoid valve 26 open when the downward distance value is greater than or equal to the preset distance value.

[0055] When the hydraulic press starts working, the first solenoid valve 22, the second solenoid valve 24 and the third solenoid valve 26 are all kept open, respectively energizing and opening the corresponding first machine valve 21, second machine valve 23 and third machine valve 25. The opening of the first machine valve 21 opens the second oil circuit 2. Under negative pressure, oil is injected into the upper chamber 41 of the return cylinder 4 through the first oil passage 1. The direction of the oil pressure is indicated by the solid arrow. The oil pressure acts on the upper chamber 41 of the return cylinder 4, on the piston inside the return cylinder 4, and squeezes it into the lower chamber 42 of the return cylinder 4. The oil in the lower chamber 42 enters the second oil passage 2, passes through the first valve 21, and enters the second valve 23 from the inlet of the fast-flow second valve 23. Then, it enters the third valve 25 from the outlet of the second valve 23. The oil in the second oil passage 2 can also directly enter from the inlet of the third valve 25. Finally, it flows into the return oil tank 6 through the outlet of the third valve 25, thus allowing the oil to quickly return to the return oil tank 6, thereby achieving the effect of the hydraulic press slide block 3 descending rapidly.

[0056] During the rapid descent, the descent distance acquisition module 51 obtains the descent distance value of the hydraulic press slider 3 from the rangefinder 7 and transmits the descent distance value to the distance comparison module 52. The distance comparison module 52 compares the descent distance value with a preset distance value, where the preset distance value is the safe descent distance of the hydraulic press slider 3. If the descent distance value is greater than or equal to the preset distance value, the solenoid valve control module 53 closes the second valve 23 for rapid flow, allowing the oil to flow more slowly through the first valve 21 and the third valve 25 for slow flow back to the oil tank 6. This reduces the speed of the hydraulic press slider 3, preventing excessive impact pressure from the hydraulic press slider on the mold and processing medium.

[0057] See Figure 2 The downward speed acquisition module 54 acquires the downward speed value of the hydraulic press slider 3 measured by the speed sensor 8; the speed comparison module 55 compares the downward speed value with the speed threshold; the preset distance reduction module 56 reduces the preset distance value to the first threshold when the downward speed value is greater than the speed threshold; the preset distance increase module 57 increases the preset distance value to the second threshold when the downward speed value is less than the speed threshold.

[0058] During the rapid descent of the hydraulic press slide 3, the descent speed acquisition module 54 acquires the descent speed value of the hydraulic press slide 3 measured by the speed sensor 8 in real time. It compares the descent speed value with a speed threshold, which is the maximum critical speed during the rapid descent of the hydraulic press slide 3. If the descent speed value is greater than the speed threshold, it means that even after the hydraulic press slide 3 descends a preset distance, further deceleration will still cause a significant pressure impact on the mold and processing medium. Therefore, the preset distance reduction module 56 reduces the preset distance value to a first threshold, where the first threshold is the distance the hydraulic press slide 3 descends when it decelerates earlier. This allows the hydraulic press slide 3 to decelerate earlier during the rapid descent. If the descent speed value is less than the speed threshold, decelerating according to the initial preset distance value results in a smaller pressure impact on the mold and processing medium, but lower hydraulic press efficiency. Therefore, the preset distance increase module 57 increases the preset distance value to a second threshold, allowing the hydraulic press slide 3 to descend a larger distance rapidly, thereby improving the efficiency of the hydraulic press's downward mold closing.

[0059] See Figure 1 and Figure 2 When the downlink distance value is greater than or equal to the preset distance value, the speed reduction calculation module 58 calculates the speed reduction based on the downlink speed value obtained by the downlink speed acquisition module 54 within a preset time. The speed reduction comparison module 59 compares the speed reduction with the preset speed reduction threshold. The fault display module 510 is coupled to the display screen 9. When the speed reduction is greater than the speed reduction threshold, it generates fault information and displays it on the display screen 9.

[0060] The return cylinder 4 includes an oil distribution pipe 43, which connects the upper cavity 41 and the lower cavity 42. A fourth solenoid valve 44 is provided at one end of the oil distribution pipe 43 near the upper cavity 41. The fourth solenoid valve 44 is used to control the opening and closing of the oil distribution pipe 43. The fourth solenoid valve 44 is coupled to the channel control module 511. When the speed drop is greater than the drop threshold, the channel control module 511 controls the fourth solenoid valve 44 to open.

[0061] When the downward distance of the hydraulic press slider 3 is greater than or equal to a preset distance, the second solenoid valve 24 closes and the hydraulic press slider 3 begins to decelerate. The speed reduction calculation module 58 calculates the speed reduction based on the different downward speed values ​​obtained by the downward speed acquisition module 54 within a preset time. For example, if the preset time is 5 seconds, the downward speed value before 5 seconds is 100 mm / s, and the downward speed value after 5 seconds is 90 mm / s, then the speed reduction within the preset time is 10 mm / s. The reduction threshold is the normal reduction within the preset time, for example, 8 mm / s. If the speed reduction of 10 mm / s is greater than the reduction threshold of 8 mm / s, it indicates that closing the second solenoid valve 24 has not been effective, and the hydraulic press has not decelerated properly. This indicates that the second solenoid valve 24 has malfunctioned. The fault display module 510 displays the fault information on the display screen 9 to remind personnel to perform maintenance. Furthermore, the channel control module 511 is activated, opening the previously closed fourth solenoid valve 44. Oil in the upper chamber 41 of the return cylinder 4 enters the lower chamber 42 through the oil distribution pipe 43, thus reducing the oil pressure in the upper chamber 41. This reduces the downward driving force exerted by the return cylinder 4 on the hydraulic press slider 3, and slows the downward movement of the hydraulic press slider 3 driven by the main cylinder. This prevents the hydraulic press slider 3 from exerting significant pressure impact on the mold and processing medium during mold closing. It should be noted that the opening of the oil distribution pipe 43 near the upper chamber 41 is larger than the opening near the lower chamber 42, resulting in lower oil pressure in the lower chamber 42 compared to the upper chamber 41.

[0062] See Figure 3 In another embodiment, the scheme is basically the same as the above embodiment, except that the structure of the return cylinder 4 is different. In this embodiment, the return cylinder 4 includes an upper cylinder body 45, a lower cylinder body 46, and a return piston 47. The return piston 47 includes an upper push rod 471, a lower push rod 472, and a piston block 473. The cross-sectional area of ​​the upper cylinder body 45 is larger than that of the lower cylinder body 46. The outer wall of the piston block 473 is in contact with the inner wall of the upper cylinder body 45, and the outer wall of the lower push rod 472 is in contact with the inner wall of the lower cylinder body 46. The oil distribution pipe 43 connects the bottom wall of the upper cylinder body 45 and the side wall of the lower cylinder body 46, and the oil distribution pipe 43 connects the upper cylinder body 45 and the lower cylinder body 46. When the channel control module 511 is activated, the fourth solenoid valve 44 on the oil distribution pipe 43 is opened, allowing the oil in the lower cylinder 46 to enter the bottom of the upper cylinder 45 through the oil distribution pipe 43, thereby buffering the downward movement of the return piston 47 in the return cylinder 4 and reducing the downward speed of the hydraulic press slider 3.

[0063] The implementation principle of a hydraulic fast / slow speed switching system for controlling the downward pressure of a hydraulic press slider according to an embodiment of this application is as follows: When the hydraulic press starts working, the first solenoid valve 22, the second solenoid valve 24, and the third solenoid valve 26 are all opened, allowing the oil in the second oil circuit 2 to flow rapidly to the return oil tank 6 through the first mechanical valve 21, the second mechanical valve 23, and the third mechanical valve 25, causing the hydraulic press slider 3 to descend rapidly. During the descent, the speed comparison module 55 compares the descent speed value of the hydraulic press slider 3 with a speed threshold. If the descent speed value is greater than the speed threshold, the preset distance reduction module 56 reduces the preset distance value to the first threshold; if the descent speed value is less than the speed threshold, the preset distance increase module 57 increases the preset distance value to the second threshold. Next, when the downward distance value of the hydraulic press slider 3 obtained by the downward distance acquisition module 51 is greater than or equal to the preset distance value, the solenoid valve control module 53 closes the second solenoid valve 24, while keeping the first solenoid valve 22 and the third solenoid valve 26 open. The oil pressure flows slowly to the return oil tank 6 through the first machine valve 21 and the third machine valve 25, thereby controlling the downward speed of the hydraulic press slider 3 and reducing the pressure impact of the hydraulic press slider 3 on the mold and processing medium.

[0064] See Figure 4 This application also provides a method for controlling the downward pressure of a hydraulic press slide by switching between fast and slow hydraulic speeds, specifically including:

[0065] S100: Obtain the downward distance value of the hydraulic press slider 3 measured by the rangefinder 7.

[0066] S101: Obtain the downward speed value of the hydraulic press slider 3 as measured by the speed sensor 8.

[0067] S102: Compare the downlink speed value with the speed threshold.

[0068] S103: If the downlink speed value is greater than the speed threshold, the preset distance value will be reduced to the first threshold.

[0069] S104: If the downlink speed value is less than the speed threshold, the preset distance value is increased to the second threshold.

[0070] S105: Compare the downlink distance value with the preset distance value.

[0071] S106: When the downlink distance value is greater than or equal to the preset distance value, close the second solenoid valve 24 and keep the first solenoid valve 22 and the third solenoid valve 26 open.

[0072] S107: Calculate the speed reduction based on the next return fuel tank speed value obtained within a preset time.

[0073] S108: Compare the speed reduction with the preset reduction threshold.

[0074] S109: If the speed drop exceeds the drop threshold, a fault message is generated and displayed on the display screen 9.

[0075] S110: Controls the opening of the fourth solenoid valve 44.

[0076] The foregoing description is merely an exemplary embodiment of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Other embodiments of this disclosure will be readily apparent to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described herein. The specification and embodiments are to be considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

Claims

1. A hydraulic fast / slow speed switching system for controlling the downward pressure of a hydraulic press slide, comprising a first oil circuit (1), a second oil circuit (2), a hydraulic press slide (3), and a return cylinder (4), wherein the return cylinder (4) comprises an upper cavity (41) and a lower cavity (42), the first oil circuit (1) is connected to the upper cavity (41), the second oil circuit (2) is connected to the lower cavity (42), a first mechanical valve (21) for controlling the opening and closing of the second oil circuit (2) is provided on the second oil circuit (2), the first mechanical valve (21) is connected to a first solenoid valve (22), and the hydraulic press slide (3) is fixedly connected to the return cylinder (4), characterized in that, The second oil circuit (2) is equipped with a second valve (23) and a third valve (25) for controlling the return oil speed. The second valve (23) is located between the first valve (21) and the third valve (25). The oil inlet of the second valve (23) and the oil inlet of the third valve (25) are both connected to the second oil circuit (2). The oil outlet of the second valve (23) and the oil outlet of the third valve (25) are connected to a return oil tank (6). The second valve (23) is connected to a second solenoid valve (24), and the third valve (25) is connected to a third solenoid valve (26). The system also includes an intelligent device (5). The solenoid valve (22), the second solenoid valve (24), and the third solenoid valve (26) are all coupled to the intelligent device (5). The intelligent device (5) is coupled to a rangefinder (7). The intelligent device (5) includes: a down-distance acquisition module (51) for acquiring the down-distance value of the hydraulic press slider (3) measured by the rangefinder (7); a distance comparison module (52) for comparing the down-distance value with a preset distance value; and a solenoid valve control module (53) for closing the second solenoid valve (24) and keeping the first solenoid valve (22) and the third solenoid valve (26) open when the down-distance value is greater than or equal to the preset distance value. 6) Open; the second valve (23) is a fast flow valve, and the third valve (25) is a slow flow valve; the intelligent device (5) is coupled with a speed sensor (8), and the intelligent device (5) further includes: a downward speed acquisition module (54) for acquiring the downward speed value of the hydraulic press slider (3) measured by the speed sensor; a speed comparison module (55) for comparing the downward speed value with a speed threshold; a preset distance reduction module (56) for reducing the preset distance value to a first threshold when the downward speed value is greater than the speed threshold; the intelligent device (5) further includes: a preset distance increase module (57) The intelligent device (5) is coupled to a display screen (9) and includes: a speed reduction calculation module (58), used to calculate the speed reduction based on the downlink speed value obtained by the downlink speed acquisition module (54) within a preset time when the downlink distance value is greater than or equal to the preset distance value; a reduction comparison module (59), used to compare the speed reduction with a preset reduction threshold; and a fault display module (510), used to generate fault information and display it on the display screen when the speed reduction is greater than the reduction threshold.

2. The hydraulic fast / slow speed switching system for controlling the downward pressure of the hydraulic press slide according to claim 1, characterized in that: The return cylinder (4) includes an oil distribution pipe (43), which connects the upper cavity (41) and the lower cavity (42). A fourth solenoid valve (44) is provided at one end of the oil distribution pipe (43) near the upper cavity (41), and the fourth solenoid valve (44) is coupled to the intelligent device (5).

3. The hydraulic fast / slow speed switching system for controlling the downward pressure of the hydraulic press slider according to claim 2, characterized in that, The smart device (5) also includes: The channel control module (511) is coupled to the fourth solenoid valve (44) and is used to control the fourth solenoid valve (44) to open when the speed drop is greater than the drop threshold.

4. A hydraulic fast / slow speed switching method based on the hydraulic fast / slow speed switching system for controlling the downward pressure of a hydraulic press slide according to any one of claims 1-3, characterized in that, include: Obtain the downward distance value of the hydraulic press slider (3) measured by the rangefinder (7); Compare the downlink distance value with the preset distance value; If the downward distance value is greater than or equal to the preset distance value, the second solenoid valve (24) is closed, while the first solenoid valve (22) and the third solenoid valve (26) remain open.

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