A screening machine hydraulic control system and screening machine

Abstract

The utility model discloses a kind of screening machine hydraulic control system and screening machine, comprising: at least two hydraulic cylinders, any two hydraulic cylinders are not worked simultaneously;Hydraulic pump, for supplying hydraulic oil to hydraulic cylinder;Switch valve group, between hydraulic pump and hydraulic cylinder, switch valve group includes at least two switch valves, switch valve and hydraulic cylinder one-to-one correspondence, for controlling the oil path conduction between hydraulic pump to corresponding hydraulic cylinder;Electric proportional valve, between hydraulic pump and switch valve group, for adjusting the action speed of each hydraulic cylinder.When hydraulic cylinder works, the switch valve of hydraulic cylinder correspondence opens, and the hydraulic oil supplied by hydraulic pump sequentially passes electric proportional valve and switch valve, and enters the hydraulic cylinder required to work.By setting electric proportional valve, the action of hydraulic cylinder is controlled using electric proportional valve and switch valve, and electric proportional valve can adjust the speed of the action of hydraulic cylinder, so that each hydraulic cylinder has suitable action speed.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic control technology for screening machines, and more specifically, to a hydraulic control system for a screening machine. Furthermore, this utility model also relates to a screening machine including the aforementioned hydraulic control system. Background Technology

[0002] For screening equipment, in some application scenarios, in addition to using motors to control the speed of the belt, it is also necessary to use hydraulic cylinders for auxiliary operation to control belt folding, belt lifting or adjusting the feeder.

[0003] However, in related technologies, the movement of hydraulic cylinders is controlled by switching valves, and the speed of hydraulic cylinder movement is not adjustable. This can lead to significant speed differences between different hydraulic cylinders, especially for those with different cylinder diameters.

[0004] Therefore, how to adjust the operating speed of the hydraulic cylinder is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide a hydraulic control system for a screening machine, which can realize the adjustment of the action speed of the hydraulic cylinder.

[0006] Another objective of this invention is to provide a screening machine that includes the above-mentioned hydraulic control system for screening machines, and the operating speed of the hydraulic cylinder can be adjusted.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A hydraulic control system for a screening machine includes:

[0009] At least two hydraulic cylinders, and any two of the hydraulic cylinders do not work simultaneously;

[0010] A hydraulic pump is used to supply hydraulic oil to the hydraulic cylinder;

[0011] A switching valve assembly is connected between the hydraulic pump and the hydraulic cylinder. The switching valve assembly includes at least two switching valves, each corresponding to a hydraulic cylinder, and is used to control the oil circuit connection between the hydraulic pump and the corresponding hydraulic cylinder.

[0012] An electro-proportional valve, connected between the hydraulic pump and the switching valve assembly, is used to adjust the operating speed of each of the hydraulic cylinders.

[0013] Optionally, it also includes:

[0014] A motor and an electro-proportional multi-way valve, wherein the electro-proportional multi-way valve is connected between the hydraulic pump and the motor, and is used to allow the hydraulic oil output by the hydraulic pump to enter the motor through the electro-proportional multi-way valve.

[0015] Optionally, the number of motors is at least one, the electro-proportional multi-way valve includes at least one working link, one working link controls one motor, and each motor rotates in one direction.

[0016] Each of the working links includes an electro-proportional directional valve, a first electro-proportional valve, and a second electro-proportional valve. The first electro-proportional valve and the second electro-proportional valve are respectively connected to the control port of the electro-proportional directional valve. The electro-proportional directional valve includes a first working port and a second working port. The first working port is connected to the return port of the corresponding motor, and the second working port is connected to the inlet port of the corresponding motor.

[0017] When the motor is working, the first electro-proportional valve of the corresponding working link is not working;

[0018] The electro-proportional valve is the first electro-proportional valve in one of the working links, and the first working port of one of the working links is connected to the switching valve assembly.

[0019] Optionally, the number of motors is five, namely a coarse material belt motor, a fine material belt motor, a transition belt motor, a feeder belt motor, and a medium material belt motor;

[0020] The electro-proportional valve is the first electro-proportional valve of the working link corresponding to the medium material belt motor, and the first working oil port of the working link corresponding to the medium material belt motor is connected to the switching valve group.

[0021] Optionally, a pressure reducing valve is provided between the hydraulic pump and the first and second electro-proportional valves of all the working links, so that the hydraulic oil of the hydraulic pump enters the first or second electro-proportional valve of each of the working links via the pressure reducing valve.

[0022] Optionally, in two hydraulic cylinders with different cylinder diameters, the current value of the hydraulic cylinder with the larger cylinder diameter corresponding to the electro-proportional valve is greater than the current value of the hydraulic cylinder with the smaller cylinder diameter corresponding to the electro-proportional valve.

[0023] Optionally, when the required hydraulic cylinder needs to be activated, the electro-proportional valve is energized after a preset time delay compared to the corresponding switching valve.

[0024] Optionally, when the hydraulic cylinder starts or stops, the current signal of the electro-proportional valve is a ramp signal.

[0025] Optionally, the hydraulic pump is a load-sensitive hydraulic pump.

[0026] A screening machine, comprising any of the above-mentioned screening machine hydraulic control systems.

[0027] The hydraulic control system for the screening machine provided by this utility model has the following beneficial effects:

[0028] When the required hydraulic cylinder is to operate, the corresponding switching valve opens, while the other switching valves in the valve group close. Hydraulic oil supplied by the hydraulic pump passes through the electro-proportional valve and then into the corresponding switching valve, and finally into the hydraulic cylinder to be operated. Since the electro-proportional valve can proportionally adjust the valve opening or output pressure according to the input electrical signal (e.g., current or voltage), the appropriate operating speed of the hydraulic cylinder can be achieved by inputting an electrical signal corresponding to the hydraulic cylinder to the electro-proportional valve. Furthermore, the operating speed of the hydraulic cylinder can be adjusted by regulating the magnitude of the electrical signal input to the electro-proportional valve. Additionally, since no two hydraulic cylinders operate simultaneously—that is, only one hydraulic cylinder operates at a time while the others remain inactive—the operating speed of each hydraulic cylinder can be controlled using a single electro-proportional valve.

[0029] In other words, the hydraulic control system of this screening machine uses an electro-proportional valve and a switching valve to jointly control the action of the hydraulic cylinder. The electro-proportional valve can adjust the speed of the hydraulic cylinder, which helps to ensure that each hydraulic cylinder has a suitable action speed.

[0030] The screening machine provided by this utility model includes the above-mentioned screening machine hydraulic control system, and has at least the beneficial effects of the above-mentioned screening machine hydraulic control system. Attached Figure Description

[0031] 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 embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 The schematic diagram of the hydraulic control system of the screening machine provided in a specific embodiment of this utility model is shown.

[0033] Figure label:

[0034] 1-Hydraulic cylinder; 11-Fine material belt lifting cylinder; 12-Screen frame lifting cylinder; 13-Feeder sliding cylinder; 14-Feeder side plate cylinder; 15-1# medium material belt folding cylinder; 16-2# medium material belt folding cylinder; 2-Hydraulic pump; 3-Switch valve assembly; 31-Switch valve; 4-Electro-proportional valve; 5-Motor; 51-Coarse material belt motor; 52-Fine material belt motor; 53-Transition belt motor; 54-Feeder belt motor; 55-Medium material belt motor; 6-Electro-proportional multi-way valve; 61-Electro-proportional directional valve; a-First electro-proportional valve; b-Second electro-proportional valve; A-First working port; B-Second working port; 7-Pressure reducing valve. Detailed Implementation

[0035] 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.

[0036] The core of this invention is to provide a hydraulic control system for a screening machine, which enables adjustment of the operating speed of the hydraulic cylinders. Another core aspect of this invention is to provide a screening machine including the aforementioned hydraulic control system, which allows for adjustment of the operating speed of the hydraulic cylinders.

[0037] Please refer to Figure 1 This utility model provides a hydraulic control system for a screening machine, including at least two hydraulic cylinders 1, a hydraulic pump 2, a switching valve group 3, and an electro-proportional valve 4. Any two hydraulic cylinders 1 do not operate simultaneously. The hydraulic pump 2 supplies hydraulic oil to the hydraulic cylinders 1. The switching valve group 3 is connected between the hydraulic pump 2 and the hydraulic cylinders 1. The switching valve group 3 includes at least two switching valves 31, which correspond one-to-one with the hydraulic cylinders 1. The switching valves 31 are used to control the oil circuit connection between the hydraulic pump 2 and the corresponding hydraulic cylinder 1. The electro-proportional valve 4 is connected between the hydraulic pump 2 and the switching valve group 3 and is used to adjust the operating speed of each hydraulic cylinder 1.

[0038] Understandably, when the required hydraulic cylinder 1 is working, the corresponding switching valve 31 of the hydraulic cylinder 1 is opened, and the other switching valves 31 of the switching valve group 3 are closed. The hydraulic oil supplied by the hydraulic pump 2 enters the corresponding switching valve 31 through the electro-proportional valve 4, and then enters the required hydraulic cylinder 1 through the switching valve 31. Since the electro-proportional valve 4 can proportionally adjust the valve opening or output pressure according to the input electrical signal (e.g., current or voltage), the required hydraulic cylinder 1 can have a suitable operating speed by inputting an electrical signal corresponding to the required hydraulic cylinder 1 to the electro-proportional valve 4. At the same time, the operating speed of the hydraulic cylinder 1 can be adjusted by adjusting the magnitude of the electrical signal input to the electro-proportional valve 4. In addition, since any two hydraulic cylinders 1 do not work simultaneously, that is, only one hydraulic cylinder 1 works at a time, and the other hydraulic cylinders 1 do not work, the operating speed of each hydraulic cylinder 1 can be controlled by one electro-proportional valve 4.

[0039] That is, in this embodiment of the utility model, by setting an electro-proportional valve 4, the electro-proportional valve 4 and the switching valve 31 are used to jointly control the action of the hydraulic cylinder 1. The electro-proportional valve 4 can adjust the action speed of the hydraulic cylinder 1, which is beneficial to make each hydraulic cylinder 1 have a suitable action speed.

[0040] Furthermore, in some embodiments, among two hydraulic cylinders 1 with different cylinder diameters, the current value of the hydraulic cylinder 1 with the larger cylinder diameter corresponding to the electro-proportional valve 4 is greater than the current value of the hydraulic cylinder 1 with the smaller cylinder diameter corresponding to the electro-proportional valve 4.

[0041] For ease of understanding, any two hydraulic cylinders 1 with different diameters are referred to as the first hydraulic cylinder 1 and the second hydraulic cylinder 1, respectively. The diameter of the first hydraulic cylinder 1 is larger than that of the second hydraulic cylinder 1. Therefore, the current value of the electro-proportional valve 4 corresponding to the first hydraulic cylinder 1 is greater than the current value of the electro-proportional valve 4 corresponding to the second hydraulic cylinder 1.

[0042] In other words, this embodiment uses the current signal of the electro-proportional valve 4 to control the opening of the electro-proportional valve 4, thereby controlling the operating speed of the hydraulic cylinder 1. That is, the operating speed of the hydraulic cylinder 1 is determined by the magnitude of the current of the electro-proportional valve 4. Therefore, for hydraulic cylinders 1 with different cylinder diameters, by setting different current values ​​for the electro-proportional valve 4, hydraulic cylinders 1 with different cylinder diameters can have different operating speeds. That is, for hydraulic cylinders 1 with relatively larger cylinder diameters, the electro-proportional valve 4 has a larger current value, thereby ensuring that the speed of hydraulic cylinders 1 with larger cylinder diameters can meet the requirements; for hydraulic cylinders 1 with relatively smaller cylinder diameters, the electro-proportional valve 4 has a smaller current value, thereby ensuring that the speed of hydraulic cylinders 1 with smaller cylinder diameters is slower and the operation is smoother.

[0043] In addition, in some embodiments, the hydraulic control system of the screening machine also includes a motor 5 and an electro-proportional multi-way valve 6. The electro-proportional multi-way valve 6 is connected between the hydraulic pump 2 and the motor 5. The electro-proportional multi-way valve 6 is used to allow the hydraulic oil output by the hydraulic pump 2 to enter the motor 5 through the electro-proportional multi-way valve 6.

[0044] In other words, in this embodiment, the motor 5 and the hydraulic cylinder 1 share the same hydraulic pump 2. The hydraulic pump 2 supplies hydraulic oil to the hydraulic cylinder 1 and the motor 5 respectively, which can save the number of hydraulic pumps 2 and reduce equipment costs. It is understood that the electro-proportional multi-way valve 6 is used to control the speed of the motor 5. The specific structure of the electro-proportional multi-way valve 6 can be a conventional structure, which can be referred to in relevant technologies and will not be described in detail here.

[0045] Furthermore, in some embodiments, the number of motors 5 is at least one, and the electro-proportional multi-way valve 6 includes at least one working link, with one working link corresponding to control one motor 5, and each motor 5 rotates in one direction; each working link includes an electro-proportional directional valve 61, a first electro-proportional valve a and a second electro-proportional valve b, the first electro-proportional valve a and the second electro-proportional valve b are respectively connected to the control port of the electro-proportional directional valve 61, the electro-proportional directional valve 61 includes a first working port A and a second working port B, the first working port A is connected to the return port of the corresponding motor 5, and the second working port B is connected to the inlet port of the corresponding motor 5; when the motor 5 is working, the first electro-proportional valve a of the corresponding working link is not working; the electro-proportional valve 4 is the first electro-proportional valve a of one of the working links, and the first working port A of one of the working links is connected to the switching valve group 3.

[0046] In other words, in this embodiment, the first electro-proportional valve a of one working link of the electro-proportional multi-way valve 6 is used as the electro-proportional valve 4 used to control the operating speed of the hydraulic cylinder 1 in the above embodiment. It can be understood that since each motor 5 rotates in one direction, this embodiment uses the second electro-proportional valve b of each working link of the electro-proportional multi-way valve 6 to control the opening of the electro-proportional directional valve 61, thereby controlling the speed of the corresponding motor 5. In this case, the first electro-proportional valve a of each working link is idle. Therefore, the first electro-proportional valve a of one working link of the electro-proportional multi-way valve 6 can be used as the electro-proportional valve 4 in the above embodiment to control the operating speed of the hydraulic cylinder 1. This eliminates the need to specifically set up an electro-proportional valve 4 to control the operating speed of the hydraulic cylinder 1, thus saving costs.

[0047] Additionally, it should be noted that when hydraulic cylinder 1 actuates, the corresponding motor 5 in the corresponding working link must stop actuating. That is, when hydraulic cylinder 1 needs to actuate, the hydraulic oil supplied by hydraulic pump 2 enters the first electro-proportional valve a in the working link of the electro-proportional multi-way valve 6, which is connected to the switching valve group 3. The first electro-proportional valve a controls the opening of the electro-proportional directional valve 61, causing the hydraulic oil supplied by hydraulic pump 2 to enter the electro-proportional directional valve 61 and exit from the corresponding first working port A, then enter the corresponding switching valve 31, and finally enter the hydraulic cylinder 1 that needs to actuate, driving hydraulic cylinder 1 to actuate. When hydraulic cylinder 1 does not need to actuate, the operation mode of motor 5 is switched. At this time, under the action of the second electro-proportional valve b, the hydraulic oil supplied by hydraulic pump 2 enters the electro-proportional directional valve 61 and exits from the corresponding second working port B before entering motor 5. The hydraulic oil flowing out of motor 5 returns through the first working port A.

[0048] Furthermore, in some embodiments, the number of motors 5 is five, namely a coarse material belt motor 51, a fine material belt motor 52, a transition belt motor 53, a feeder belt motor 54, and a medium material belt motor 55; the electro-proportional valve 4 is the first electro-proportional valve a of the working link corresponding to the medium material belt motor 55, and the first working oil port A of the working link corresponding to the medium material belt motor 55 is connected to the switching valve group 3.

[0049] In other words, in this embodiment, the first electro-proportional valve a of the working link corresponding to the intermediate material belt motor 55 is used as the electro-proportional valve 4 in the above embodiment to control the operating speed of the hydraulic cylinder 1. Since the operation of the intermediate material belt motor 55 is relatively less compared to the coarse material belt motor 51, fine material belt motor 52, transition belt motor 53 and feeder belt motor 54, using the first electro-proportional valve a of the working link corresponding to the intermediate material belt motor 55 as the electro-proportional valve 4 in the above embodiment can reduce the number of times the working mode of the motor 5 and the operating mode of the hydraulic cylinder 1 are switched.

[0050] It should be noted that the above embodiments do not limit the specific number and type of hydraulic cylinders 1. For example, the number of hydraulic cylinders 1 is six, namely, fine material belt lifting cylinder 11, screen frame lifting cylinder 12, feeder sliding cylinder 13, feeder side plate cylinder 14, #1 medium material belt folding cylinder 15, and #2 medium material belt folding cylinder 16. Correspondingly, the switch valve group 3 includes six switch valves 31, which respectively control the fine material belt lifting cylinder 11, screen frame lifting cylinder 12, feeder sliding cylinder 13, feeder side plate cylinder 14, #1 medium material belt folding cylinder 15, and #2 medium material belt folding cylinder 16.

[0051] In addition, in some embodiments, a pressure reducing valve 7 is provided between the hydraulic pump 2 and the first electro-proportional valve a and the second electro-proportional valve b of all working links, so that the hydraulic oil of the hydraulic pump 2 enters the first electro-proportional valve a or the second electro-proportional valve b of each working link via the pressure reducing valve 7.

[0052] In other words, this embodiment controls the pressure of hydraulic oil entering the first electro-proportional valve a and the second electro-proportional valve b of all working links by setting a pressure reducing valve 7.

[0053] In addition, to avoid impacting the hydraulic control system of the screening machine, in some embodiments, when the required hydraulic cylinder 1 needs to be activated, the electro-proportional valve 4 is energized after a preset time delay compared to the corresponding switching valve 31.

[0054] In other words, in this embodiment, when the required hydraulic cylinder 1 needs to be activated, the switching valve 31 corresponding to the required hydraulic cylinder 1 is opened first, and then the electro-proportional valve 4 is opened. This can avoid the hydraulic control system of the screening machine being impacted by hydraulic oil, which is beneficial to improving the reliability of the hydraulic control system of the screening machine.

[0055] It should be noted that this embodiment does not limit the specific value of the preset time for which the electro-proportional valve 4 is delayed in energizing compared to the corresponding switching valve 31. For example, the preset time for which the electro-proportional valve 4 is delayed in energizing compared to the corresponding switching valve 31 is less than or equal to 500 milliseconds. For instance, the preset time for which the electro-proportional valve 4 is delayed in energizing compared to the corresponding switching valve 31 could be 400 milliseconds, 300 milliseconds, 200 milliseconds, or 100 milliseconds, etc. The key is that the preset time for which the electro-proportional valve 4 is delayed in energizing compared to the corresponding switching valve 31 is sufficient to avoid hydraulic shock to the hydraulic control system of the screening machine.

[0056] In addition, in some embodiments, when the hydraulic cylinder 1 starts or stops, the current signal of the electro-proportional valve 4 is a ramp signal.

[0057] In other words, in this embodiment, at the moment when the hydraulic cylinder 1 starts or stops, the current signal of the electro-proportional valve 4 adopts a ramp signal, which can improve the smoothness of the hydraulic cylinder 1's movement, thereby overcoming the reversing impact of the hydraulic cylinder 1 when the switching valve 31 starts or stops.

[0058] Furthermore, the above embodiments do not limit the specific type and structure of the switching valve 31. For example, the switching valve 31 can be a solenoid valve.

[0059] In addition, the above embodiments do not limit the specific type and structure of the hydraulic pump 2. In some embodiments, the hydraulic pump 2 is a load-sensitive hydraulic pump.

[0060] It is understandable that load-sensitive hydraulic pumps are variable pumps, which can automatically adjust the output flow and pressure according to the load demand, thereby providing the flow and pressure required by the system to reduce energy loss and improve system efficiency.

[0061] In addition to the hydraulic control system of the screening machine described above, this utility model embodiment also provides a screening machine including the hydraulic control system of the screening machine disclosed in the above embodiment. For the structure of other parts of the screening machine, please refer to the prior art, which will not be repeated here.

[0062] The key point of this embodiment is that the screening machine adopts the screening machine hydraulic control system disclosed in any of the above embodiments, so that the screening machine includes at least the beneficial effects of the above screening machine hydraulic control system, which will not be repeated here.

[0063] It should also be noted that, in this specification, relational terms such as first and second are used only 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.

[0064] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0065] The hydraulic control system and screening machine of this utility model have been described in detail above. Specific examples have been used to illustrate the principle and implementation of this utility model. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core idea of ​​this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of this utility model.

Claims

1. A hydraulic control system for a screening machine, characterized in that, include: At least two hydraulic cylinders (1), and any two of the hydraulic cylinders (1) do not work simultaneously; A hydraulic pump (2) is used to supply hydraulic oil to the hydraulic cylinder (1); A switching valve assembly (3) is connected between the hydraulic pump (2) and the hydraulic cylinder (1). The switching valve assembly (3) includes at least two switching valves (31). Each switching valve (31) corresponds to a hydraulic cylinder (1) and is used to control the oil circuit connection between the hydraulic pump (2) and the corresponding hydraulic cylinder (1). An electro-proportional valve (4) is connected between the hydraulic pump (2) and the switching valve group (3) to adjust the operating speed of each of the hydraulic cylinders (1).

2. The hydraulic control system for the screening machine according to claim 1, characterized in that, Also includes: The motor (5) and the electro-proportional multi-way valve (6) are connected between the hydraulic pump (2) and the motor (5) to allow the hydraulic oil output by the hydraulic pump (2) to enter the motor (5) through the electro-proportional multi-way valve (6).

3. The hydraulic control system for the screening machine according to claim 2, characterized in that, The number of motors (5) is at least one, and the electro-proportional multi-way valve (6) includes at least one working link, one working link controls one motor (5), and each motor (5) rotates in one direction; Each of the working links includes an electro-proportional directional valve (61), a first electro-proportional valve (a), and a second electro-proportional valve (b). The first electro-proportional valve (a) and the second electro-proportional valve (b) are respectively connected to the control port of the electro-proportional directional valve (61). The electro-proportional directional valve (61) includes a first working port (A) and a second working port (B). The first working port (A) is connected to the return port of the corresponding motor (5), and the second working port (B) is connected to the inlet port of the corresponding motor (5). When the motor (5) is working, the first electro-proportional valve (a) of the corresponding working link is not working; The electro-proportional valve (4) is the first electro-proportional valve (a) of one of the working links, and the first working port (A) of one of the working links is connected to the switching valve group (3).

4. The hydraulic control system for the screening machine according to claim 3, characterized in that, The number of motors (5) is five, namely, coarse material belt motor (51), fine material belt motor (52), transition belt motor (53), feeder belt motor (54) and medium material belt motor (55). The electro-proportional valve (4) is the first electro-proportional valve (a) of the working link corresponding to the medium material belt motor (55), and the first working oil port (A) of the working link corresponding to the medium material belt motor (55) is connected to the switching valve group (3).

5. The hydraulic control system for the screening machine according to claim 3, characterized in that, A pressure reducing valve (7) is provided between the hydraulic pump (2) and the first electro-proportional valve (a) and the second electro-proportional valve (b) of all the working links, so that the hydraulic oil of the hydraulic pump (2) enters the first electro-proportional valve (a) or the second electro-proportional valve (b) of each of the working links via the pressure reducing valve (7).

6. The hydraulic control system for the screening machine according to any one of claims 1-5, characterized in that, In the two hydraulic cylinders (1) with different cylinder diameters, the current value of the hydraulic cylinder (1) with the larger cylinder diameter corresponding to the electro-proportional valve (4) is greater than the current value of the hydraulic cylinder (1) with the smaller cylinder diameter corresponding to the electro-proportional valve (4).

7. The hydraulic control system for the screening machine according to any one of claims 1-5, characterized in that, When the required hydraulic cylinder (1) needs to be activated, the electro-proportional valve (4) is energized after a preset time delay compared to the corresponding switching valve (31).

8. The hydraulic control system for the screening machine according to any one of claims 1-5, characterized in that, When the hydraulic cylinder (1) starts or stops, the current signal of the electro-proportional valve (4) is a ramp signal.

9. The hydraulic control system for the screening machine according to any one of claims 1-5, characterized in that, The hydraulic pump (2) is a load-sensitive hydraulic pump.

10. A screening machine, characterized in that, The hydraulic control system for the screening machine as described in any one of claims 1-9.

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