A flow-controllable hydraulic system for machinery and its control method

Abstract

This invention relates to the field of engineering machinery technology, and discloses a flow-controllable hydraulic system for implements and its control method. The system includes an implement rotary motor, a control valve, a controller, and a speed sensor. The P port of the control valve is connected to the P3 port of the excavator's main hydraulic valve, and the T port of the control valve is connected to the excavator's hydraulic oil tank. The A and B ports of the control valve are respectively connected to the A and B ports of the implement rotary motor. The controller is communicatively connected to both the speed sensor and the control valve. The speed sensor is connected to the implement rotary motor to collect its rotational speed and transmit the collected speed to the controller. The beneficial effects of this invention are: the hydraulic oil flow rate in the implement rotary circuit can be autonomously set according to the needs of different implements, and the flow rate can be controlled in real time, maintaining a stable oil supply to the rotary circuit.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to a flow-controllable hydraulic system for machinery and its control method. Background Technology

[0002] Hydraulic excavators are increasingly widely used, allowing for different tasks to be performed by changing different attachments, such as hydraulic shears, log grapples, and sorting grapples. Some attachments have a rotating function, enabling 360° rotation and expanding the working range; currently, this rotation function is generally achieved by using hydraulic oil to drive a hydraulic motor.

[0003] Currently, there are generally two methods to achieve slewing of machinery:

[0004] Option 1 involves installing a dedicated fixed displacement pump system on the excavator for fuel supply, with the fuel supply volume adjustable through program settings to ensure stable implement rotation speed. However, this requires adding a fixed displacement pump, increasing costs; furthermore, this option is not feasible for excavators without a pre-installed PTO port.

[0005] Option 2: The hydraulic circuit for the implement rotation draws oil from the excavator's main valve port (usually P3), and the speed of the implement is controlled by a corresponding control valve. The hydraulic schematic diagram is shown below. Figure 1 However, the hydraulic oil flow rate in the machine's rotation circuit is affected by other actions, making it difficult to ensure smooth machine operation during complex actions. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a hydraulic system for machinery with controllable flow rate and its control method, which enables the hydraulic oil flow rate in the rotating oil circuit of the machinery to be set independently according to the needs of different attachments, and the flow rate can be controlled in real time, maintaining a stable oil supply to the rotating oil circuit.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] In a first aspect, this invention proposes a flow-controllable hydraulic system for a workpiece, comprising a workpiece rotary motor, a control valve, a controller, and a speed sensor; the P port of the control valve is connected to the oil port P3 of the excavator's main hydraulic valve, and the T port of the control valve is connected to the excavator's hydraulic oil tank; the A and B ports of the control valve are respectively connected to the A and B ports of the workpiece rotary motor; the controller is communicatively connected to both the speed sensor and the control valve; the speed sensor is connected to the workpiece rotary motor to collect the rotational speed of the workpiece rotary motor and transmit the collected rotational speed to the controller; the controller receives the rotational speed of the workpiece rotary motor and calculates the real-time flow rate Q of the workpiece rotary motor based on the rotational speed of the workpiece rotary motor. 实时 and the real-time flow rate Q of the machine's rotary motor 实时 With the set flow rate Q设 The comparison is performed to obtain the comparison results, and then the adjustment command is sent to the control valve based on the comparison results.

[0009] In conjunction with the first aspect, the control valve further includes a solenoid directional valve and a proportional solenoid valve. The a port of the proportional solenoid valve is connected to the P port of the control valve, and the b port is connected to the A port of the solenoid directional valve. The C port of the solenoid directional valve is connected to the A port of the control valve, the D port of the solenoid directional valve is connected to the B port of the control valve, and the B port of the solenoid directional valve is connected to the T port of the control valve.

[0010] In conjunction with the first aspect, the proportional solenoid valve is a two-position two-way solenoid valve; the solenoid directional valve is a three-position four-way solenoid valve.

[0011] In conjunction with the first aspect, the control valve of the present invention further includes a first relief valve and a second relief valve; the oil inlet of the first relief valve is connected to port A of the control valve, and the oil outlet is connected to port T of the control valve; the oil inlet of the second relief valve is connected to port B of the control valve, and the oil outlet is connected to port T of the control valve.

[0012] In conjunction with the first aspect, the hydraulic system of the present invention further includes a pressure sensor connected to a proportional solenoid valve for collecting the oil supply pressure of the rotary motor of the machine and transmitting the collected oil supply pressure data to the controller. The controller receives the oil supply pressure data of the rotary motor of the machine and determines whether to reduce the flow supply based on the oil supply pressure data of the rotary motor of the machine. When the oil supply pressure of the rotary motor of the machine exceeds or approaches the set pressure of the two relief valves, the flow supply is reduced, thereby reducing energy loss.

[0013] In conjunction with the first aspect, the control valve further includes a first solenoid valve and a first directional control valve. The inlet (c) of the first solenoid valve is connected to the outlet (b) of the proportional solenoid valve, and the outlet (d) is connected to the control valve (T). The inlet (e) of the first directional control valve is connected to the outlet (b) of the proportional solenoid valve, and the outlet (f) is connected to the control valve (T). The first solenoid valve is communicatively connected to a controller, which sends opening and closing signals to the first solenoid valve. The first solenoid valve is also connected to the first directional control valve to control its switching and opening / closing.

[0014] Secondly, this invention proposes a control method for a hydraulic system of machinery with controllable flow rate, comprising the following steps:

[0015] Step S1, during initial operation, the proportional solenoid valve is energized, and the current value is I. max / 2, at this time the valve core opening of the proportional solenoid valve is in the middle, the flow rate is moderate, I max This is the maximum current value.

[0016] Step S2, if the real-time flow rate Q of the machine's rotary motor 实时 <Set flow rate Q> 设 And | Real-time traffic Q 实时 - Set flow rate Q 设 If the threshold is reached, the controller sends a signal to the proportional solenoid valve to increase the current value I, thereby increasing the valve opening and increasing the oil supply to the machine's rotary motor until the set flow rate Q is reached. 设 ;

[0017] Step S3, if the controller controls the proportional solenoid valve to reach the maximum current value I. max And the real-time flow rate Q of the machine's rotary motor 实时 <Set flow rate Q> 设 In addition, | real-time traffic Q 实时 - Set flow rate Q 设 If the value is greater than or equal to the threshold, the controller sends a signal to the excavator's main pump to increase the pump's displacement and increase the flow rate Q of the hydraulic system (it should be noted that Q is related to Q...). 实时 Positive correlation, in the case of a single action (i.e., only the machine rotation operation), Q=Q 实时 Until the set flow rate Q is reached. 设 ;

[0018] Step S4, if the real-time flow rate Q of the machine's rotary motor 实时 > Set the flow rate Q 设 And real-time traffic Q 实时 - Set flow rate Q 设 > Threshold (preferred threshold is 5% × Q) 设 Then adjust the flow rate in the reverse manner of steps 2 and 3 until it drops to the set flow rate Q. 设 .

[0019] Thirdly, the present invention provides an excavator including the aforementioned implement hydraulic system.

[0020] Compared with the prior art, the present invention provides a hydraulic system for machinery with controllable flow rate and its control method, which has the following beneficial effects:

[0021] (1) The flow rate of the rotating oil circuit of the present invention can be set independently according to the needs of different attachments, and the flow rate can be controlled in real time, thus maintaining the stable oil supply of the rotating oil circuit.

[0022] (2) The hydraulic system of the present invention uses a speed sensor to collect the rotation speed of the rotating tool and transmits the signal to the controller; the controller controls the opening size of the oil supply solenoid valve according to the speed signal, thereby realizing the real-time adjustment of the rotation speed of the tool, and thus the flow rate of the rotating tool can be adjusted in real time to ensure the stability of the rotation speed of the tool.

[0023] (3) When the pressure of the machine tool in this invention is close to the system overflow set pressure, the machine tool flow rate is automatically adjusted to reduce the overflow flow rate and achieve energy saving. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the hydraulic system for achieving slewing on an excavator in the prior art (where X1 and X2 are the pilot ports of the implement control valve).

[0025] Figure 2 This is a schematic diagram of the hydraulic system in Example 1;

[0026] Figure 3 This is a schematic diagram of the hydraulic system in Example 2.

[0027] The meanings of the reference numerals in the figure are as follows:

[0028] 1-Machine rotary motor; 2-Control valve; 3-Controller; 4-Proportional solenoid valve; 5-Solenoid directional valve; 6-Speed ​​sensor; 7-Pressure sensor; 8-First relief valve; 9-Second relief valve; 10-First solenoid valve; 11-First directional valve. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may include different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0031] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of the present invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of the present invention.

[0032] Example 1

[0033] The hydraulic schematic diagram of the hydraulic system of the machine in this embodiment is as follows: Figure 2 As shown ( Figure 2 (The main valve, main pump, etc. are not visible).

[0034] This embodiment proposes a flow-controllable hydraulic system for a workpiece, including a workpiece rotary motor 1, a control valve 2, a controller 3, and a speed sensor 6. The P port of the control valve 2 is connected to the oil port P3 of the excavator's main hydraulic valve, and the T port of the control valve 2 is connected to the excavator's hydraulic oil tank. The A and B ports of the control valve 2 are connected to the A and B ports of the workpiece rotary motor 1, respectively. The controller 3 is communicatively connected to the speed sensor 6 and the control valve 2. The speed sensor 6 is connected to the workpiece rotary motor 1 to collect its rotational speed and transmit the collected speed to the controller 3. The controller 3 receives the rotational speed of the workpiece rotary motor 1 and calculates the real-time flow rate Q of the workpiece rotary motor 1 based on the rotational speed. 实时 and the real-time flow rate Q of the rotating motor 1 of the machine. 实时 With the set flow rate Q 设 The comparison is performed to obtain the comparison result, and then the adjustment command is sent to control valve 2 based on the comparison result.

[0035] In one specific implementation of this embodiment, the control valve 2 includes a solenoid directional valve 5 and a proportional solenoid valve 4. The a port of the proportional solenoid valve 4 is connected to the P port of the control valve 2, and the b port is connected to the A port of the solenoid directional valve 5. The C port of the solenoid directional valve 5 is connected to the A port of the control valve 2, the D port of the solenoid directional valve 5 is connected to the B port of the control valve 2, and the B port of the solenoid directional valve 5 is connected to the T port of the control valve 2.

[0036] In one specific implementation of this embodiment, the proportional solenoid valve 4 is a two-position two-way solenoid valve; the solenoid directional valve 5 is a three-position four-way solenoid valve.

[0037] In one specific embodiment of this invention, the control valve 2 of the present invention further includes a first relief valve 8 and a second relief valve 9; the oil inlet of the first relief valve 8 is connected to the A port of the control valve 2, and the oil outlet is connected to the T port of the control valve 2; the oil inlet of the second relief valve 9 is connected to the B port of the control valve 2, and the oil outlet is connected to the T port of the control valve 2.

[0038] In one specific implementation of this embodiment, the hydraulic system of the tool of the present invention further includes a pressure sensor 7, which is connected to a proportional solenoid valve 4 and is used to collect the oil supply pressure of the tool rotary motor and transmit the collected oil supply pressure data to the controller 3. The controller 3 receives the oil supply pressure data of the tool rotary motor and uses it to determine whether it is necessary to reduce the flow supply based on the oil supply pressure data of the tool rotary motor 1. When the oil supply pressure of the tool rotary motor 1 exceeds or approaches the set pressure of the two relief valves (i.e., the first relief valve 8 and the second relief valve 9), the flow supply is reduced, thereby reducing energy loss.

[0039] In the working mode of the implement, before the implement starts working, set the required hydraulic oil flow rate Q and pressure value P of the implement rotary motor 1 on the excavator display screen according to the type of implement and working conditions.

[0040] The P port of control valve 2 is connected to the oil port P3 of the main valve, and the T port is connected to the hydraulic oil tank of the excavator.

[0041] Taking forward rotation of the implement as an example, this embodiment describes the operation of the implement during working. Oil enters port A of the implement rotary motor 1, causing the implement to rotate forward. The operator operates the implement button on the control handle to control the implement's forward rotation. At this time, the proportional solenoid valve 4 is energized (initial current value is I). max / 2,I max (Indicating the maximum current value), proportional solenoid valve 4 is in the upper position, with its ports a and b connected. Simultaneously, the left solenoid coil of solenoid directional valve 5 is energized, and the valve core of solenoid directional valve 5 is in the left position, with its ports A and C connected. Hydraulic oil flows into control valve 2 through port P, and from port A of control valve 2 into port A of the implement rotary motor 1, causing the implement rotary motor 1 to start rotating forward. Simultaneously, hydraulic oil flows out from port B of the implement rotary motor 1, sequentially passing through port B of control valve 2, port D and port B of solenoid directional valve 5, and finally returning to the excavator's hydraulic oil tank through port T of control valve 2.

[0042] During the above process, pressure sensor 7 and speed sensor 6 transmit signals to controller 3 of the hydraulic system of the implement in this embodiment. Controller 3 calculates the real-time flow rate Q of the implement rotary motor 1 based on the following expression and the real-time speed n of the implement rotary motor 1. 实时 .

[0043] Q_real-time = q × n × η

[0044] Where q is the displacement of the machine rotary motor and η is the volumetric efficiency of the machine rotary motor, both of which are known quantities; n is the real-time rotational speed of the machine rotary motor, which is collected by a speed sensor.

[0045] When the real-time flow rate Q of the rotating motor 1 of the machine 实时 With the set flow rate Q 设 The absolute value of the difference ΔQ exceeds the threshold (the threshold varies depending on the machine and needs to be set according to the machine; the preferred threshold is 5% × Q). 设 The controller 3 controls the current value of the proportional solenoid valve 4 to control the size of the valve core opening of the proportional solenoid valve 4, thereby controlling the flow rate into the machine rotary motor 1.

[0046] The specific adjustment process is as follows:

[0047] Step S1, during initial operation, the proportional solenoid valve 4 is energized, with a current value of I. max / 2, at this time the valve core opening of the proportional solenoid valve 4 is in the middle, the flow rate is moderate, I max This is the maximum current value.

[0048] Step S2, if the real-time flow rate Q of the machine's rotary motor 1 实时 <Set flow rate Q> 设 And | Real-time traffic Q 实时 - Set flow rate Q 设 |>Threshold (preferred threshold is 5% × Q) 设 Then, controller 3 sends a signal to proportional solenoid valve 4 to increase the current value I, thereby increasing the valve core opening of proportional solenoid valve 4 and increasing the oil supply of the machine rotary motor 1 until the set flow rate Q is reached. 设 .

[0049] Step S3, if the current value of the proportional solenoid valve 4 controlled by the controller 3 reaches the maximum current value I. max And the real-time flow rate Q of the rotating motor 1 of the machine 实时 <Set flow rate Q> 设 In addition, | real-time traffic Q 实时 - Set flow rate Q 设 |≥ Threshold (preferred threshold is 5% × Q) 设 Then, controller 3 sends a signal to the excavator's main pump to increase the pump's displacement, thereby increasing the flow rate of the hydraulic system in this embodiment until the set flow rate Q is reached. 设 .

[0050] Step S4, if the real-time flow rate Q of the machine rotary motor 1 实时 > Set the flow rate Q 设 And real-time traffic Q 实时 - Set flow rate Q 设 > Threshold (preferred threshold is 5% × Q) 设If the flow rate is reduced, then adjust the flow rate in the reverse manner as in step 2 to reduce the flow rate of the hydraulic system of the machine in this embodiment until it drops to the set flow rate Q. 设 .

[0051] During the above adjustment process, the operation of controller 3 is as follows:

[0052] Step I: Controller 3 calculates the real-time flow rate Q of the machine's rotary motor 1. 实时 With the set flow rate Q 设 The difference △Q.

[0053] Step II, when △Q / Q 设 When ≥5%, controller 3 determines the value based on △Q / Q. 设 The value of the current in the proportional solenoid valve 4 is reduced proportionally to change the oil supply of the machine's rotary motor 1; this process is iterated multiple times until ΔQ / Q is reached. 设 <5%; the number of iterations should not exceed 5.

[0054] Step III: When the pressure value collected by the pressure sensor is greater than or equal to the set pressure of the first relief valve 8 and the second relief valve 9, the controller 3 reduces the current value of the proportional solenoid valve 4 to reduce the amount of overflow oil and thus save energy.

[0055] Example 2

[0056] The difference between Example 2 and Example 1 is as follows: Figure 3 As shown, the control valve 2 in Embodiment 2 further includes a first solenoid valve 10 and a first directional valve 11. The oil inlet (c) of the first solenoid valve 10 is connected to the b port of the proportional solenoid valve, and the oil outlet (d) is connected to the T port of the control valve 2. The oil inlet (e) of the first directional valve 11 is connected to the b port of the proportional solenoid valve, and the oil outlet (f) is connected to the T port of the control valve 2. The first solenoid valve 10 is communicatively connected to the controller 3, which sends opening and closing signals to the first solenoid valve 10. The first solenoid valve 10 is connected to the first directional valve 11 to control the switching and opening / closing of the first directional valve 11. The first solenoid valve 10 and the first directional valve 11 together form a pressure valve for setting the overflow pressure value, which can be quickly set by the controller 3.

[0057] The first solenoid valve 10 receives a set pressure value signal, which is converted into an electrical signal by the controller 3 and acts on the first solenoid valve 10. When the pressure value in the hydraulic system exceeds the set pressure value, the valve core of the first solenoid valve 10 opens, and port c connects to port d, allowing some pressure oil to return to the hydraulic oil tank. At this time, the pressure at port c is lower than the pressure at port e. The pressure at port c acts on the lower end of the valve core of the first directional valve 11, while the pressure at port e acts on the upper end of the valve core of the first directional valve 11. As the pressure at port c decreases, the force acting on the lower end of the first directional valve 11 decreases, and the valve core moves downward under the hydraulic force. At this time, ports e and f of the first directional valve 11 connect, and pressure oil returns to the oil tank from port f, completing the overflow.

[0058] Example 3

[0059] This embodiment proposes an excavator, including the aforementioned hydraulic system.

[0060] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hydraulic system for machinery with controllable flow rate, characterized in that: The system includes a tool rotary motor, a control valve, a controller, and a speed sensor. The P port of the control valve is connected to the P3 port of the excavator's main hydraulic valve, and the T port of the control valve is connected to the excavator's hydraulic oil tank. The A and B ports of the control valve are respectively connected to the A and B ports of the tool rotary motor. The controller is communicatively connected to both the speed sensor and the control valve. The speed sensor is connected to the tool rotary motor to collect its rotational speed and transmit the collected speed to the controller. The controller receives the rotational speed of the machine's rotary motor and calculates the real-time flow rate Q of the machine's rotary motor based on the rotational speed. 实时 and the real-time flow rate Q of the machine's rotary motor 实时 With the set flow rate Q 设 The comparison is performed to obtain the comparison result, and then the adjustment command is sent to the control valve based on the comparison result; The control valve includes a solenoid directional valve and a proportional solenoid valve. Port a of the proportional solenoid valve is connected to port P of the control valve, and port b is connected to port A of the solenoid directional valve. Port C of the solenoid directional valve is connected to port A of the control valve, port D of the solenoid directional valve is connected to port B of the control valve, and port B of the solenoid directional valve is connected to port T of the control valve. It also includes a first relief valve and a second relief valve; the oil inlet of the first relief valve is connected to port A of the control valve, and the oil outlet is connected to port T of the control valve; the oil inlet of the second relief valve is connected to port B of the control valve, and the oil outlet is connected to port T of the control valve. It also includes a pressure sensor, which is connected to a proportional solenoid valve to collect the oil supply pressure of the machine's rotary motor and transmit the collected oil supply pressure data to the controller. The controller receives the oil supply pressure data of the machine's rotary motor and uses it to determine whether the flow rate needs to be reduced based on the oil supply pressure data of the machine's rotary motor.

2. The hydraulic system for controllable flow rate of machinery according to claim 1, characterized in that: The proportional solenoid valve is a two-position two-way solenoid valve; the solenoid directional valve is a three-position four-way solenoid valve.

3. The flow-controllable hydraulic system for machinery according to claim 1, characterized in that: The control valve further includes a first solenoid valve and a first directional control valve. The inlet (c) of the first solenoid valve is connected to the outlet (b) of the proportional solenoid valve, and the outlet (d) is connected to the control valve (T). The inlet (e) of the first directional control valve is connected to the outlet (b) of the proportional solenoid valve, and the outlet (f) is connected to the control valve (T). The first solenoid valve is communicatively connected to a controller, which sends opening and closing signals to the first solenoid valve. The first solenoid valve is also connected to the first directional control valve to control its switching and opening / closing.

4. A control method for a hydraulic system of a machine with controllable flow rate, characterized in that, The hydraulic system for machinery based on any one of claims 1 to 3 includes the following steps: Step S1: During initial operation, the proportional solenoid valve is energized, and the current value is I. max / 2, at this time the valve core opening of the proportional solenoid valve is in the middle, the flow rate is moderate, I max This is the maximum current value; Step S2, if the real-time flow rate Q of the machine's rotary motor 实时 <Set flow rate Q> 设 And | Real-time traffic Q 实时 - Set flow rate Q 设 If the threshold is reached, the controller sends a signal to the proportional solenoid valve to increase the current value I, thereby increasing the valve opening and increasing the oil supply to the machine's rotary motor until the set flow rate Q is reached. 设 ; Step S3, if the controller controls the proportional solenoid valve to reach the maximum current value I. max And the real-time flow rate Q of the machine's rotary motor 实时 <Set flow rate Q> 设 In addition, | real-time traffic Q 实时 - Set flow rate Q 设 If the flow rate is greater than or equal to the threshold, the controller sends a signal to the excavator's main pump to increase the pump's displacement and increase the flow rate Q of the hydraulic system until the set flow rate Q is reached. 设 ; Step S4, if the real-time flow rate Q of the machine's rotary motor 实时 > Set the flow rate Q 设 And real-time traffic Q 实时 - Set flow rate Q 设 If the flow rate exceeds the threshold, adjust the flow rate in the reverse manner of steps 2 and 3 until it drops to the set flow rate Q. 设 .

5. An excavator, characterized in that: Includes the hydraulic system of the machine as described in any one of claims 1 to 3.

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