Concrete distribution apparatus and hydraulic control system and control method thereof

Abstract

This invention provides a hydraulic control system for a concrete placing boom, comprising a hydraulic oil tank, an oil supply pump unit, a main hydraulic pressure pipeline, a main return hydraulic pipeline, and at least one hydraulic actuator unit. The oil supply pump unit is located on the main hydraulic pressure pipeline. Each hydraulic actuator unit includes a hydraulic cylinder and a control valve assembly. The control valve assembly is located close to the hydraulic cylinder, or integrated onto the hydraulic cylinder. The control valve assembly includes a main directional valve, a standby directional valve, and a balance valve assembly. The inlet ports of the main directional valve and the standby directional valve are respectively connected to the main hydraulic pressure pipeline. The return ports of the main directional valve and the standby directional valve are respectively connected to the main return hydraulic pipeline. The outlet ports of the main directional valve and the standby directional valve are respectively connected to the hydraulic cylinder via the balance valve assembly. This invention also provides a control method for the hydraulic control system of the concrete placing boom and a concrete placing boom device.

Description

Technical Field

[0001] This invention relates to the field of concrete placing equipment technology, and in particular to a concrete placing equipment and its hydraulic control system and control method. Background Technology

[0002] Concrete placing equipment is the final stage of concrete pumping, typically including concrete pump trucks and concrete placing booms (see patents CN204001766U and CN114704096A for details). Its function is to deliver pumped concrete through pipelines to the formwork of the component to be poured. The hydraulic control system of the concrete placing equipment is the core component controlling the movement of its boom, thereby completing various concrete placing actions.

[0003] like Figure 1 As shown, the existing hydraulic control system of concrete placing equipment generally includes a hydraulic oil tank 91, a hydraulic oil pump 92, a reversing valve assembly 93, a balance valve assembly 94, and a cylinder 95 (boom cylinder). The hydraulic oil pump 92 draws hydraulic oil from the hydraulic oil tank 91, and then pumps the hydraulic oil through the reversing valve assembly 93 and the balance valve assembly 94 in sequence to the cylinder 95, thereby driving the cylinder 95 to work and thus driving the boom to move. The hydraulic oil tank 91, hydraulic oil pump 92, and reversing valve assembly 93 are all located at the lower position of the concrete placing equipment (i.e., the chassis position), while the balance valve assembly 94 and cylinder 95 are both located on the boom, and the balance valve assembly 94 and cylinder 95 are integrated. The reversing valve assembly 93 is a multi-way valve, which includes multiple reversing valves 931 arranged in parallel. Each reversing valve 931 is connected to the corresponding balance valve assembly 94 and cylinder 95 through a pressure oil line 96 and a return oil line 97. One end of the hydraulic oil line 96 and the return oil line 97 are connected to the reversing valve 931 located at the chassis position, and the other end is laid along the boom to the corresponding position of the hydraulic cylinder 95. However, the existing hydraulic control system of the concrete placing equipment has the following problems:

[0004] 1. Because the chassis is far from the boom, and the directional valve assembly 93 is located on the chassis while the hydraulic cylinder 95 is located on the boom, the distance between the directional valve assembly 93 (control element) and the hydraulic cylinder 95 (actuator element) is far, which in turn causes the hydraulic cylinder 95 to have a slow response speed.

[0005] Meanwhile, since the directional valve group 93 adopts a multi-way valve, each directional valve 931 is connected to the corresponding balance valve group 94 and oil cylinder 95 through the pressure oil line 96 and the return oil line 97 respectively. This results in a large number of pipelines, long pipeline distances, heavy weight, and affects the space layout. In addition, the pipeline diameter is small, and the pressure loss and friction loss of the hydraulic system are large and the efficiency is low during the operation of the boom.

[0006] 2. Since the boom typically operates at high altitudes, the temperature of the hydraulic oil in the pressure oil line 96 and return oil line 97 is close to ambient temperature. Therefore, the oil temperature in the lines is significantly affected by the ambient temperature. Especially in low-temperature environments, the cold oil in the lines cannot be exchanged quickly, resulting in slow system response, large pressure loss, and low efficiency. Current hydraulic control systems cannot sense the oil temperature in the pressure oil line 96, and cannot promptly address abnormal oil temperatures.

[0007] 3. Each hydraulic cylinder 95 is controlled by a single directional valve 931. When the directional valve 931 malfunctions, the boom cannot perform emergency operations, posing a significant safety hazard. Summary of the Invention

[0008] The purpose of this invention is to provide a hydraulic control system for concrete placing equipment, which can improve the response speed of hydraulic cylinders, save the number of pipelines, and reduce system pressure loss; at the same time, it adopts a backup directional valve, which can perform emergency operation on the boom when the main directional valve fails.

[0009] This invention provides a hydraulic control system for a concrete placing equipment, comprising a hydraulic oil tank, an oil supply pump unit, a main oil pressurization pipeline, a main oil return pipeline, and at least one hydraulic actuator unit; one end of the main oil pressurization pipeline is connected to the hydraulic oil tank, and the oil supply pump unit is disposed on the main oil pressurization pipeline; one end of the main oil return pipeline is connected to the hydraulic oil tank.

[0010] Each of the hydraulic actuators includes a hydraulic cylinder and a control valve assembly. The control valve assembly is located close to the hydraulic cylinder, or the control valve assembly is integrated onto the hydraulic cylinder. The control valve assembly includes a main directional valve, a standby directional valve, and a balance valve assembly. The inlet ports of the main directional valve and the standby directional valve are respectively connected to the main hydraulic oil pipeline. The return ports of the main directional valve and the standby directional valve are respectively connected to the main return oil pipeline. The outlet ports of the main directional valve and the standby directional valve are respectively connected to the hydraulic cylinder through the balance valve assembly.

[0011] Furthermore, the balance valve assembly includes a first balance valve, a second balance valve, a first check valve, and a second check valve. The first balance valve and the first check valve are connected in parallel in opposite directions, and the second balance valve and the second check valve are also connected in parallel in opposite directions. The first outlet of the main directional valve and the first outlet of the standby directional valve are both connected to the outlet of the first balance valve and the inlet of the first check valve. The inlet of the first balance valve and the outlet of the first check valve are both connected to one port of the hydraulic cylinder. The second outlet of the main directional valve and the second outlet of the standby directional valve are both connected to the outlet of the second balance valve and the inlet of the second check valve. The inlet of the second balance valve and the outlet of the second check valve are both connected to the other port of the hydraulic cylinder.

[0012] Furthermore, both the first balancing valve and the second balancing valve are pilot-operated balancing valves; the control port of the first balancing valve is connected to the second outlet of the main directional valve and the second outlet of the standby directional valve, and the control port of the second balancing valve is connected to the first outlet of the main directional valve and the first outlet of the standby directional valve.

[0013] Furthermore, the hydraulic control system of the concrete placing equipment also includes an oil temperature detection unit and a control unit. The oil temperature detection unit is used to detect the oil temperature of the hydraulic oil in the hydraulic oil tank and the hydraulic oil in the main oil pressure pipeline. A radiator for cooling the hydraulic oil is provided on the main oil return pipeline.

[0014] The main oil pressure pipeline and the main oil return pipeline are connected by a circulation pipeline, and a switching valve is provided on the circulation pipeline. The control unit is simultaneously connected to the oil temperature detection unit, the switching valve, and the radiator. The control unit is used to control the opening and closing of the switching valve and the radiator according to the oil temperature information detected by the oil temperature detection unit.

[0015] Furthermore, the oil temperature detection unit includes a main pipeline temperature sensor and an oil tank temperature sensor. The oil tank temperature sensor is connected to the hydraulic oil tank and is used to detect the hydraulic oil temperature in the hydraulic oil tank. The main pipeline temperature sensor is located on the hydraulic oil main pipeline or the circulation pipeline and is used to detect the hydraulic oil temperature in the hydraulic oil main pipeline.

[0016] Furthermore, the main pipeline temperature sensor is located at the end of the main hydraulic pipeline away from the hydraulic oil tank; or, the circulation pipeline is connected to the ends of the main hydraulic pipeline and the return pipeline away from the hydraulic oil tank, and the main pipeline temperature sensor is located on the circulation pipeline.

[0017] Furthermore, there are multiple hydraulic actuators, which are arranged in parallel in sequence; the main hydraulic pressure pipeline and the main return pipeline are respectively connected to multiple hydraulic actuators, and the end of the main hydraulic pressure pipeline and the end of the main return pipeline are connected to the last hydraulic actuator; the circulation pipeline is connected to the end of the main hydraulic pressure pipeline and the end of the main return pipeline.

[0018] Furthermore, the hydraulic control system of the concrete placing equipment also includes a pressure detection unit and an overflow valve. The pressure detection unit is used to detect the operating load pressure of the hydraulic cylinder and the outlet pressure of the oil supply pump unit. The inlet of the overflow valve is connected to the main oil pressure pipeline, and the outlet of the overflow valve is connected to the main oil return pipeline. The control unit is also connected to the pressure detection unit and the overflow valve signal, and the control unit is also used to control the overflow setting value of the overflow valve according to the pressure signal detected by the pressure detection unit and the oil temperature information detected by the oil temperature detection unit.

[0019] Furthermore, the main directional valve is a proportional directional valve, and the control unit is also signal-connected to the main directional valve and the oil supply pump unit; the control unit is also used to control the opening degree of the main directional valve and the oil supply flow rate of the oil supply pump unit according to the hydraulic oil demand flow rate of the boom movement.

[0020] The present invention also provides a control method for the hydraulic control system of the above-mentioned concrete placing equipment, the control method comprising:

[0021] When the oil temperature detection unit detects that the hydraulic oil temperature in the main hydraulic pipeline is lower than the set value or the hydraulic oil temperature in the hydraulic oil tank, the control unit controls the switch valve to open and the radiator to close, so that the hydraulic oil in the hydraulic oil tank is circulated back to the hydraulic oil tank through the main hydraulic pipeline, the circulation pipeline and the return oil pipeline in sequence.

[0022] When the oil temperature detection unit detects that the hydraulic oil temperature in the hydraulic oil tank is higher than the control value, the control unit controls the opening of both the switching valve and the radiator, so that the hydraulic oil in the hydraulic oil tank circulates back to the hydraulic oil tank in sequence through the main pressure pipeline, the circulation pipeline, the return oil main pipeline and the radiator.

[0023] The present invention also provides a concrete placing device, including the above-mentioned hydraulic control system for the concrete placing device, wherein the hydraulic cylinder and control valve group in each of the hydraulic actuators are mounted on the boom of the concrete placing device; there are multiple hydraulic actuators, which are arranged in parallel in sequence, and the main hydraulic oil pipeline and the main return oil pipeline are respectively connected to the multiple hydraulic actuators.

[0024] The hydraulic control system for concrete placing equipment provided by this invention features a distributed arrangement of control valve groups for each hydraulic actuator. This means that the control valve groups of each hydraulic actuator are positioned close to or integrated onto the hydraulic cylinder, thereby shortening the distance between the control valve groups and the hydraulic cylinder and improving the response speed of the hydraulic cylinder. Furthermore, the control valve groups of each hydraulic actuator can be connected in parallel to the main pressure oil pipeline and the main return oil pipeline, meaning that the same main pipeline can be used to connect the hydraulic cylinders on each boom section. This eliminates the need to lay long pressure oil pipelines and return oil pipelines between each directional valve and its corresponding cylinder, thus saving on the number of pipelines. Simultaneously, the main pressure oil pipeline and the main return oil pipeline can use large-diameter pipelines, thereby reducing system pressure loss and further improving the response speed of the hydraulic cylinder.

[0025] Meanwhile, the control valve group is equipped with a main directional valve and a backup directional valve. The main directional valve is the commonly used directional valve. When the main directional valve fails, the backup directional valve can replace the main directional valve to control the hydraulic cylinder, thereby enabling emergency operation of the boom and improving the safety of the system. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the hydraulic control system of a concrete placing equipment in the prior art.

[0027] Figure 2 This is a schematic diagram of the hydraulic control system of the concrete placing equipment in an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the control logic of the hydraulic control system of the concrete placing equipment in an embodiment of the present invention.

[0029] Figure 4 This is a schematic diagram of the hydraulic control system of the concrete placing equipment in another embodiment of the present invention.

[0030] Figure 5 This is a schematic diagram of the control logic of the hydraulic control system for a concrete placing equipment in another embodiment of the present invention. Detailed Implementation

[0031] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0032] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and claims of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0033] The directional terms such as "up," "down," "left," "right," "front," "back," "top," and "bottom" (if present) used in the specification and claims of this invention are defined by the position of the structures in the drawings and the relative positions of the structures, and are only for the clarity and convenience of expressing the technical solution. It should be understood that the use of directional terms should not limit the scope of protection claimed in this application.

[0034] like Figure 2 and Figure 3 As shown, the hydraulic control system for a concrete placing boom provided in this embodiment of the invention includes a hydraulic oil tank 1, an oil supply pump unit 10, a main hydraulic pressure pipeline 2, a main return hydraulic pressure pipeline 3, and at least one hydraulic actuator 4. The hydraulic oil tank 1 stores hydraulic oil, the oil supply pump unit 10 draws and pumps the hydraulic oil from the hydraulic oil tank 1, the main hydraulic pressure pipeline 2 delivers the hydraulic oil to the hydraulic actuator 4, and the main return hydraulic pressure pipeline 3 returns the hydraulic oil to the hydraulic oil tank 1. One end of the main hydraulic pressure pipeline 2 is connected to the hydraulic oil tank 1, and the oil supply pump unit 10 is mounted on the main hydraulic pressure pipeline 2. One end of the main return hydraulic pressure pipeline 3 is connected to the hydraulic oil tank 1.

[0035] Each hydraulic actuator 4 includes a hydraulic cylinder 41 (i.e., a boom cylinder mounted on the boom) and a control valve assembly (not labeled in the figure). The hydraulic cylinder 41 is connected to the main hydraulic oil line 2 and the main return hydraulic oil line 3 via the control valve assembly. The control valve assembly is located close to the hydraulic cylinder 41, or the control valve assembly is integrated on the hydraulic cylinder 41 (i.e., the control valve assembly is mounted on the hydraulic cylinder 41). The control valve assembly includes a main directional valve 42, a standby directional valve 43, and a balance valve assembly. The main directional valve 42 and the standby directional valve 43 are connected in parallel. The inlet ports of the main directional valve 42 and the standby directional valve 43 are both connected to the main hydraulic oil line 2, and the return ports of the main directional valve 42 and the standby directional valve 43 are both connected to the main return hydraulic oil line 3. The outlet ports of the main directional valve 42 and the standby directional valve 43 are both connected to the hydraulic cylinder 41 via the balance valve assembly.

[0036] The hydraulic control system for the concrete placing boom provided in this embodiment adopts a distributed arrangement for the control valve groups of each hydraulic actuator 4. That is, the control valve groups of each hydraulic actuator 4 are set close to or integrated on the hydraulic cylinder 41 (instead of using a multi-way valve to integrate multiple directional valves together), thereby shortening the distance between the control valve groups and the hydraulic cylinder 41 and improving the response speed of the hydraulic cylinder 41. Moreover, the control valve groups of each hydraulic actuator 4 can be connected in parallel to the main pressure oil line 2 and the main return oil line 3, that is, the same main line is used to connect to the hydraulic cylinders 41 on each boom section. It is not necessary to lay long pressure oil lines and return oil lines between each directional valve and the corresponding cylinder, thereby saving the number of lines. At the same time, the main pressure oil line 2 and the main return oil line 3 can use large-diameter lines, thereby reducing system pressure loss and further improving the response speed of the hydraulic cylinder 41.

[0037] Meanwhile, the control valve group is equipped with a main directional valve 42 and a standby directional valve 43. The main directional valve 42 is the commonly used directional valve. When the main directional valve 42 fails, the standby directional valve 43 can replace the main directional valve 42 to control the hydraulic cylinder 41, thereby enabling emergency operation of the boom and improving the safety of the system.

[0038] like Figure 2 and Figure 3 As shown, in one embodiment, the hydraulic control system of the concrete placing equipment also includes an oil temperature detection unit 5 and a control unit 7. A radiator 31 for cooling the hydraulic oil is installed on the return oil main line 3. The pressure oil main line 2 and the return oil main line 3 are connected by a circulation pipeline 20, which is equipped with a switching valve 21 for opening or closing the circulation pipeline 20. The oil temperature detection unit 5 is used to detect the hydraulic oil temperature in the hydraulic oil tank 1 and the hydraulic oil temperature in the pressure oil main line 2. The control unit 7 is simultaneously connected to the oil temperature detection unit 5, the switching valve 21, and the radiator 31, and controls the opening and closing of the switching valve 21 and the radiator 31 based on the oil temperature information detected by the oil temperature detection unit 5.

[0039] Specifically, the hydraulic oil main line 2 and the return oil main line 3 are connected by a circulation pipeline 20, and a switch valve 21 is installed on the circulation pipeline 20. When the oil temperature detection unit 5 detects that the hydraulic oil temperature in the hydraulic oil main line 2 is lower than the set value or the hydraulic oil temperature in the hydraulic oil tank 1, the control unit 7 controls the switch valve 21 to open and the radiator 31 to close, so that the hydraulic oil in the hydraulic oil tank 1 circulates back to the hydraulic oil tank 1 through the hydraulic oil main line 2, the circulation pipeline 20 and the return oil main line 3 in sequence. This allows for rapid circulation and exchange of cold oil in the pipeline and rapid circulation and transfer of hot oil in the hydraulic oil tank 1 to the pipeline, thereby improving the system response speed, reducing system pressure loss and improving work efficiency. When the oil temperature detection unit 5 detects that the hydraulic oil temperature in the hydraulic oil tank 1 is higher than the control value, the control unit 7 controls both the switching valve 21 and the radiator 31 to open. This allows the hydraulic oil in the hydraulic oil tank 1 to circulate back to the hydraulic oil tank 1 sequentially through the main pressure oil pipeline 2, the circulation pipeline 20, the return oil main pipeline 3, and the radiator 31. This circulation of hot oil in the radiator 31 and pipelines improves heat dissipation efficiency and prevents abnormal operation caused by excessively high oil temperature (the switching valve 21 is closed during normal operation). Through the coordinated operation of the control unit 7, the oil temperature detection unit 5, the radiator 31, and the switching valve 21, the oil temperature in the pipelines and the hydraulic oil tank 1 is regulated.

[0040] like Figure 2 As shown, in one embodiment, the balance valve assembly includes a first balance valve 44, a second balance valve 45, a first check valve 46, and a second check valve 47. The first balance valve 44 and the first check valve 46 are connected in parallel in opposite directions (i.e., the inlet of the first balance valve 44 is connected to the outlet of the first check valve 46, and the outlet of the first balance valve 44 is connected to the inlet of the first check valve 46). The second balance valve 45 and the second check valve 47 are connected in parallel in opposite directions. The first oil outlet of the main directional valve 42 and the first oil outlet of the standby directional valve 43 are both connected to the outlet of the first balance valve 44 and the inlet of the first check valve 46. The inlet of the first balance valve 44 and the outlet of the first check valve 46 are both connected to one oil port of the hydraulic cylinder 41. The second outlet of the main directional valve 42 and the second outlet of the standby directional valve 43 are both connected to the outlet of the second balance valve 45 and the inlet of the second check valve 47. The inlet of the second balance valve 45 and the outlet of the second check valve 47 are both connected to the other port of the hydraulic cylinder 41. The two ports of the hydraulic cylinder 41 are a rod-side port and a rodless-side port. The rod-side port communicates with the rod-side chamber of the hydraulic cylinder 41, and the rodless-side port communicates with the rodless-side chamber of the hydraulic cylinder 41 (in this embodiment, the inlet of the first balance valve 44 and the outlet of the first check valve 46 are both connected to the rodless-side port of the hydraulic cylinder 41, and the inlet of the second balance valve 45 and the outlet of the second check valve 47 are both connected to the rod-side port of the hydraulic cylinder 41). Of course, in other embodiments, the balance valve assembly can also use other valve combinations.

[0041] like Figure 2 As shown, in one embodiment, both the first balancing valve 44 and the second balancing valve 45 are pilot-operated balancing valves. The control port of the first balancing valve 44 is connected to the second outlet of the main directional valve 42 and the second outlet of the standby directional valve 43, and the control port of the second balancing valve 45 is connected to the first outlet of the main directional valve 42 and the first outlet of the standby directional valve 43. Of course, in other embodiments, the first balancing valve 44 and the second balancing valve 45 can also be other types of balancing valves, such as electrically controlled balancing valves.

[0042] Specifically, during operation, when the main directional valve 42 is opened, the oil inlet of the main directional valve 42 is connected to its first oil outlet, and the oil return port of the main directional valve 42 is connected to its second oil outlet, the hydraulic oil in the hydraulic oil main pipeline 2 passes through the first oil outlet of the main directional valve 42 and the first check valve 46 in sequence to reach the rodless chamber of the hydraulic cylinder 41. At the same time, the second balance valve 45 is opened, so that the hydraulic oil in the rod chamber of the hydraulic cylinder 41 flows back to the return oil main pipeline 3 through the second balance valve 45 and the second oil outlet of the main directional valve 42 in sequence. At this time, the piston rod of the hydraulic cylinder 41 extends. When the main directional valve 42 is opened, the oil inlet of the main directional valve 42 is connected to its second oil outlet, and the oil return port of the main directional valve 42 is connected to its first oil outlet. The hydraulic oil in the hydraulic oil main pipeline 2 passes through the second oil outlet of the main directional valve 42 and the second check valve 47 in sequence to reach the rod chamber of the hydraulic cylinder 41. At the same time, the first balance valve 44 is opened, so that the hydraulic oil in the rodless chamber of the hydraulic cylinder 41 flows back to the return oil main pipeline 3 through the first balance valve 44 and the first oil outlet of the main directional valve 42 in sequence. At this time, the piston rod of the hydraulic cylinder 41 retracts.

[0043] like Figure 2 and Figure 3 As shown, in one embodiment, the oil temperature detection unit 5 includes a main pipeline temperature sensor 51 and an oil tank temperature sensor 52. The control unit 7 is simultaneously connected to both the main pipeline temperature sensor 51 and the oil tank temperature sensor 52. The oil tank temperature sensor 52 is connected to the hydraulic oil tank 1 and is used to detect the temperature of the hydraulic oil in the hydraulic oil tank 1. The main pipeline temperature sensor 51 is installed on the hydraulic oil main pipeline 2 or the circulation pipeline 20 and is used to detect the temperature of the hydraulic oil in the hydraulic oil main pipeline 2.

[0044] like Figure 2As shown, in one embodiment, the circulation pipeline 20 is connected to the end of the main hydraulic oil pipeline 2 and the return oil pipeline 3 furthest from the hydraulic oil tank 1, and the main pipeline temperature sensor 51 is installed on the circulation pipeline 20. In another embodiment, the main pipeline temperature sensor 51 is installed at the end of the main hydraulic oil pipeline 2 furthest from the hydraulic oil tank 1. Since the main hydraulic oil pipeline 2 is generally quite long, the hydraulic oil temperature at different locations in the pipeline is inconsistent (generally, the hydraulic oil temperature is higher closer to the hydraulic oil tank 1 and lower further away from the hydraulic oil tank 1). In this embodiment, the main pipeline temperature sensor 51 is used to detect the hydraulic oil temperature at the end of the main hydraulic oil pipeline 2, so that the temperature detection result can represent the lowest temperature level of the hydraulic oil in the pipeline, thereby facilitating the temperature control of the low-temperature hydraulic oil in the pipeline (since the main hydraulic oil pipeline 2 is installed on the boom, and the boom is relatively high, the hydraulic oil in the main hydraulic oil pipeline 2 is prone to low temperature, which increases the viscosity of the hydraulic oil in the pipeline and results in a large pressure loss).

[0045] like Figure 2 As shown, in one implementation, there are multiple hydraulic actuators 4, which are connected in parallel. The main hydraulic pressure line 2 and the main return line 3 are each connected to multiple hydraulic actuators 4 (specifically, to the control valve group within the hydraulic actuator 4). This means that the same main line is used to connect to the hydraulic cylinders 41 on each arm section, eliminating the need for long hydraulic pressure and return lines between each directional valve and its corresponding cylinder, thus saving on the number of lines. Simultaneously, the ends of the main hydraulic pressure line 2 and the main return line 3 are connected to the last hydraulic actuator 4, and the circulation line 20 is connected to the ends of the main hydraulic pressure line 2 and the main return line 3. This avoids the circulation line 20 affecting normal oil circuit operation and allows the oil to flow to all positions on the main hydraulic pressure line 2 and the main return line 3 during low / high temperature circulation.

[0046] like Figure 2 and Figure 3 As shown, in one embodiment, the main directional valve 42 is a proportional directional valve (i.e., the main directional valve 42 can change the hydraulic flow through it by changing its opening degree). The control unit 7 is also signal-connected to the main directional valve 42 and the oil supply pump unit 10. The control unit 7 is also used to control the opening degree of the main directional valve 42 and the oil supply flow of the oil supply pump unit 10 according to the hydraulic oil demand flow of the boom movement (i.e., the hydraulic oil demand flow calculated by the control unit 7 based on the boom movement control command it receives), so that the oil supply flow meets the oil supply demand of the hydraulic cylinder 41.

[0047] like Figure 2 and Figure 3As shown, in one embodiment, the backup directional valve 43 is a conventional quantitative directional valve (i.e., it cannot change the hydraulic flow through it) to save costs. The control unit 7 is also signal-connected to the backup directional valve 43 to control its opening, closing, and directional actions. Of course, in other embodiments, the backup directional valve 43 can also be a proportional directional valve.

[0048] like Figure 2 and Figure 3 As shown, in one embodiment, the hydraulic control system of the concrete placing equipment also includes a pressure detection unit 6 and a relief valve 22. The pressure detection unit 6 is used to detect the operating load pressure of the hydraulic cylinder 41 and the outlet pressure of the oil supply pump unit 10. The inlet of the relief valve 22 is connected to the main oil supply line 2 (specifically, the inlet of the relief valve 22 is connected to the main oil supply line 2 after the oil supply pump unit 10), and the outlet of the relief valve 22 is connected to the return oil supply line 3. The control unit 7 is also signal-connected to the pressure detection unit 6 and the relief valve 22. The control unit 7 is also used to control the overflow setpoint of the relief valve 22 according to the pressure signal detected by the pressure detection unit 6 and the oil temperature information detected by the oil temperature detection unit 5.

[0049] Specifically, the outlet flow rate of the oil supply pump unit 10 generally needs to be greater than the oil supply demand flow rate of the hydraulic cylinder 41. By changing the overflow setting value of the overflow valve 22, the outlet flow rate of the oil supply pump unit 10 can be changed (i.e., the hydraulic flow rate exceeding the overflow setting value of the overflow valve 22 will return to the hydraulic oil tank 1 through the overflow valve 22); that is, by adjusting the overflow setting value of the overflow valve 22, the outlet flow rate of the oil supply pump unit 10 can be finely adjusted so that the displacement of the oil supply pump unit 10 can meet the demand flow rate in real time (adjusting the opening of the main directional valve 42 and the oil supply flow rate of the oil supply pump unit 10 is generally used to regulate the initial flow rate of the system, which is suitable for coarse adjustment; adjusting the overflow setting value of the overflow valve 22 can be used for fine and precise adjustment of the flow rate).

[0050] Meanwhile, existing technologies do not consider the impact of oil temperature on oil supply flow rate and cannot compensate for flow deviations caused by changes in oil temperature (for example, when the oil temperature decreases, the kinematic viscosity of the oil increases, the pressure loss increases, and the actual oil supply flow rate decreases). In this embodiment, the oil temperature detection unit 5 detects the oil temperature information, and the pressure detection unit 6 detects the operating load pressure of the hydraulic cylinder 41 and the outlet pressure of the oil supply pump unit 10, and calculates the pressure difference between the two. This is used to adjust the overflow setting value of the overflow valve 22, thereby fine-tuning the outlet flow rate of the oil supply pump unit 10 so that the displacement of the oil supply pump unit 10 can meet the demand flow rate in real time.

[0051] like Figure 2 and Figure 3As shown, in one embodiment, the pressure detection unit 6 includes a first pressure sensor 61 and a second pressure sensor 62. The control unit 7 is simultaneously connected to both the first pressure sensor 61 and the second pressure sensor 62. The first pressure sensor 61 is connected to the inner cavity of the main directional valve 42 and is used to detect the operating load pressure of the hydraulic cylinder 41. Simultaneously, the inner cavity of the main directional valve 42 is also connected to the hydraulic oil tank 1 via a pressure relief pipe 40, so that when the main directional valve 42 is not working, the hydraulic oil in the main directional valve 42 can be unloaded to the hydraulic oil tank 1 through the pressure relief pipe 40 (avoiding the presence of hydraulic oil in the main directional valve 42, which would cause the first pressure sensor 61 to always acquire a pressure signal and result in misjudgment). The second pressure sensor 62 is located on the main pressure oil pipe 2 at the outlet of the oil supply pump unit 10 and is used to detect the outlet pressure of the oil supply pump unit 10. Of course, in other embodiments, the first pressure sensor 61 and the second pressure sensor 62 can also have other configurations and locations.

[0052] like Figure 2 As shown, in one embodiment, a pressure reducing valve 48 is also provided between the oil inlet of the main directional valve 42 and the main oil pressure pipeline 2. The pressure reducing valve 48 is used to control the oil supply pressure and oil supply flow of each hydraulic actuator 4, thereby realizing the automatic distribution of flow among each hydraulic actuator 4.

[0053] like Figure 2 As shown, in one embodiment, the main oil pressure line 2 is further provided with a third check valve 23, and the main oil return line 3 is further provided with a fourth check valve 33. Filters 32 are also provided on the main oil pressure line 2 and the main oil return line 3.

[0054] like Figure 2 and Figure 3 As shown, in one embodiment, the oil supply pump unit 10 includes a variable displacement pump 11 (i.e., a pump with variable displacement). The variable displacement pump 11 is installed on the main oil pressure pipeline 2. The control unit 7 is signal-connected to the variable displacement pump 11 and is used to control the displacement of the variable displacement pump 11, thereby controlling the oil supply flow rate. Specifically, the variable displacement pump 11 can be an electronically controlled variable displacement piston pump.

[0055] like Figure 4 and Figure 5As shown, in another embodiment, the oil supply pump unit 10 includes a fixed displacement pump 12 (i.e., a pump with a fixed displacement), a flow regulating valve 13, and a return line 14. The fixed displacement pump 12 is installed on the main pressure oil line 2. One end of the return line 14 is connected to the outlet of the fixed displacement pump 12 (specifically, it is connected to the main pressure oil line 2 after the outlet of the fixed displacement pump 12), and the other end of the return line 14 is connected to the hydraulic oil tank 1. The flow regulating valve 13 is installed on the return line 14. The control unit 7 is signal-connected to the flow regulating valve 13 and the fixed displacement pump 12. The control unit 7 is used to control the opening and closing of the fixed displacement pump 12 and the opening degree of the flow regulating valve 13, thereby controlling the return flow of the oil (excess oil flows back to the hydraulic oil tank 1 through the return line 14 and the flow regulating valve 13), and thus controlling the oil supply flow (this method can be used for both coarse adjustment of the initial flow of the system and fine adjustment and micro-adjustment of the flow).

[0056] In one implementation, the main directional valve 42, the standby directional valve 43, and the switching valve 21 are all electrically controlled directional valves. The control unit 7 is also electrically connected to the oil temperature detection unit 5, the switching valve 21, the radiator 31, the relief valve 22, the pressure detection unit 6, the main directional valve 42, the standby directional valve 43, and the oil supply pump unit 10.

[0057] This invention also provides a control method for the hydraulic control system of the above-mentioned concrete placing equipment, the control method comprising:

[0058] When the oil temperature detection unit 5 detects that the hydraulic oil temperature in the main hydraulic pipeline 2 is lower than the set value or the hydraulic oil temperature in the hydraulic oil tank 1, the control unit 7 controls the switch valve 21 to open and the radiator 31 to close, so that the hydraulic oil in the hydraulic oil tank 1 is circulated back to the hydraulic oil tank 1 through the main hydraulic pipeline 2, the circulation pipeline 20 and the return oil main pipeline 3 in sequence (at this time, the main reversing valve 42 and the standby reversing valve 43 are in the closed state), thereby quickly circulating and exchanging the cold oil in the pipeline and quickly circulating and transferring the hot oil in the hydraulic oil tank 1 to the pipeline;

[0059] When the oil temperature detection unit 5 detects that the hydraulic oil temperature in the hydraulic oil tank 1 is higher than the control value, the control unit 7 controls the opening of both the switching valve 21 and the radiator 31, so that the hydraulic oil in the hydraulic oil tank 1 circulates back to the hydraulic oil tank 1 through the main pressure oil pipeline 2, the circulation pipeline 20, the return oil main pipeline 3 and the radiator 31 in sequence (at this time, the main reversing valve 42 and the standby reversing valve 43 are in the closed state), so that the hot oil circulates and dissipates heat in the radiator 31 and the pipeline.

[0060] This invention also provides a concrete placing equipment, including the aforementioned hydraulic control system. This concrete placing equipment can be a concrete pump truck, a concrete placing machine, etc. A hydraulic oil tank 1 and an oil supply pump unit 10 are located on the chassis of the concrete placing equipment. The hydraulic cylinders 41 and control valve groups in each hydraulic actuator 4 are mounted on the boom of the concrete placing equipment. One end of the main hydraulic oil line 2 and the return hydraulic oil line 3 are connected to the hydraulic oil tank 1, and the other ends of the main hydraulic oil line 2 and the return hydraulic oil line 3 are laid along the boom. There are multiple hydraulic actuators 4, which are connected in parallel. The main hydraulic oil line 2 and the return hydraulic oil line 3 are each connected to multiple hydraulic actuators 4, thus requiring only one main hydraulic oil line 2 and one return hydraulic oil line 3 in the concrete placing equipment.

[0061] As one implementation method, the working process of the hydraulic control system of the concrete placing equipment includes:

[0062] 1. When the hydraulic system is working, the control unit 7 calculates the required hydraulic oil flow rate based on the boom movement control commands it receives, and controls the opening degree of the main directional valve 42 and the oil supply flow rate of the oil supply pump unit 10 according to the calculated hydraulic oil demand flow rate. At the same time, the control unit 7 reads the pressure signal detected by the pressure detection unit 6 and the oil temperature information detected by the oil temperature detection unit 5, adjusts the overflow set value of the relief valve 22, and then fine-tunes the outlet flow rate of the oil supply pump unit 10 so that the displacement of the oil supply pump unit 10 can meet the demand flow rate in real time.

[0063] 2. The control unit 7 monitors the hydraulic oil temperature in the main hydraulic line 2 and the hydraulic oil temperature in the hydraulic oil tank 1 in real time. When the oil temperature detection unit 5 detects that the hydraulic oil temperature in the main hydraulic line 2 is lower than the set value or the hydraulic oil temperature in the hydraulic oil tank 1, in standby mode, the control unit 7 controls the switch valve 21 to open and the radiator 31 to close, so that the hydraulic oil in the hydraulic oil tank 1 circulates back to the hydraulic oil tank 1 sequentially through the main hydraulic line 2, the circulation line 20, and the return oil main line 3. When the oil temperature detection unit 5 detects that the hydraulic oil temperature in the hydraulic oil tank 1 is higher than the control value, in standby mode, the control unit 7 controls both the switch valve 21 and the radiator 31 to open, so that the hydraulic oil in the hydraulic oil tank 1 circulates back to the hydraulic oil tank 1 sequentially through the main hydraulic line 2, the circulation line 20, the return oil main line 3, and the radiator 31.

[0064] 3. When the main directional valve 42 fails, the backup directional valve 43, as an emergency operating valve, can replace the main directional valve 42 to control the hydraulic cylinder 41, thereby enabling emergency operation of the boom.

[0065] The advantages of the hydraulic control system for the concrete placing equipment provided in this embodiment include:

[0066] 1. The control valve group of each hydraulic actuator 4 is distributed, that is, the control valve group of each hydraulic actuator 4 is set close to the hydraulic cylinder 41 or integrated on the hydraulic cylinder 41 (instead of using a multi-way valve to integrate multiple directional valves together), thereby shortening the distance between the control valve group and the hydraulic cylinder 41 and improving the response speed of the hydraulic cylinder 41.

[0067] 2. The control valve groups of each hydraulic actuator 4 can be connected in parallel to the main pressure oil line 2 and the main return oil line 3. That is, the same main line is used to connect the hydraulic cylinders 41 on each arm section respectively. It is not necessary to lay long pressure oil lines and return oil lines between each directional valve and the corresponding cylinder, thereby saving the number of lines. At the same time, the main pressure oil line 2 and the main return oil line 3 can use large-diameter lines, thereby reducing system pressure loss and further improving the response speed of the hydraulic cylinders 41.

[0068] 3. The control valve group is equipped with a main directional valve 42 and a standby directional valve 43. When the main directional valve 42 fails, the standby directional valve 43 can replace the main directional valve 42 to control the hydraulic cylinder 41, thereby enabling emergency operation of the boom and improving the safety of the system.

[0069] 4. The oil temperature in the pipeline and the hydraulic oil tank 1 is regulated by the cooperation of the control unit 7, the oil temperature detection unit 5, the radiator 31 and the switching valve 21 to avoid abnormal low or high temperature of hydraulic oil.

[0070] 5. Existing technologies do not consider the impact of oil temperature on oil supply flow rate and cannot compensate for flow deviations caused by changes in oil temperature. In this embodiment, the oil temperature detection unit 5 detects oil temperature information, and the pressure detection unit 6 detects the operating load pressure of the hydraulic cylinder 41 and the outlet pressure of the oil supply pump unit 10, and calculates the pressure difference between the two. This is used to adjust the overflow setting value of the overflow valve 22, thereby fine-tuning the outlet flow rate of the oil supply pump unit 10 so that the displacement of the oil supply pump unit 10 can meet the demand flow rate in real time.

[0071] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A hydraulic control system for a concrete placing equipment, characterized in that, It includes a hydraulic oil tank, an oil supply pump unit, a main oil pressure pipeline, a main oil return pipeline, at least one hydraulic actuator unit, an oil temperature detection unit, and a control unit; one end of the main oil pressure pipeline is connected to the hydraulic oil tank, and the oil supply pump unit is disposed on the main oil pressure pipeline; one end of the main oil return pipeline is connected to the hydraulic oil tank. Each of the hydraulic actuators includes a hydraulic cylinder and a control valve assembly. The control valve assembly is located close to the hydraulic cylinder, or the control valve assembly is integrated onto the hydraulic cylinder. The control valve assembly includes a main directional valve, a standby directional valve, and a balance valve assembly. The inlet ports of the main directional valve and the standby directional valve are respectively connected to the main hydraulic oil pipeline. The return ports of the main directional valve and the standby directional valve are respectively connected to the main return oil pipeline. The outlet ports of the main directional valve and the standby directional valve are respectively connected to the hydraulic cylinder through the balance valve assembly. The return oil main line is equipped with a radiator for cooling the hydraulic oil; the pressure oil main line and the return oil main line are connected by a circulation pipeline, and a switching valve is installed on the circulation pipeline; the oil temperature detection unit is used to detect the hydraulic oil temperature in the hydraulic oil tank and the hydraulic oil temperature in the pressure oil main line; the control unit is simultaneously connected to the oil temperature detection unit, the switching valve, and the radiator, and the control unit is used to control the opening and closing of the switching valve and the radiator according to the oil temperature information detected by the oil temperature detection unit.

2. The hydraulic control system for the concrete placing equipment as described in claim 1, characterized in that, The balance valve assembly includes a first balance valve, a second balance valve, a first check valve, and a second check valve. The first balance valve and the first check valve are connected in parallel in opposite directions, and the second balance valve and the second check valve are also connected in parallel in opposite directions. The first outlet of the main directional valve and the first outlet of the standby directional valve are both connected to the outlet of the first balance valve and the inlet of the first check valve. The inlet of the first balance valve and the outlet of the first check valve are both connected to one port of the hydraulic cylinder. The second outlet of the main directional valve and the second outlet of the standby directional valve are both connected to the outlet of the second balance valve and the inlet of the second check valve. The inlet of the second balance valve and the outlet of the second check valve are both connected to the other port of the hydraulic cylinder.

3. The hydraulic control system for the concrete placing equipment as described in claim 2, characterized in that, Both the first balancing valve and the second balancing valve are pilot-operated balancing valves; the control port of the first balancing valve is connected to the second outlet of the main directional valve and the second outlet of the standby directional valve, and the control port of the second balancing valve is connected to the first outlet of the main directional valve and the first outlet of the standby directional valve.

4. The hydraulic control system for the concrete placing equipment as described in claim 1, characterized in that, The oil temperature detection unit includes a main pipeline temperature sensor and an oil tank temperature sensor. The oil tank temperature sensor is connected to the hydraulic oil tank and is used to detect the hydraulic oil temperature in the hydraulic oil tank. The main pipeline temperature sensor is installed on the hydraulic oil main pipeline or the circulation pipeline and is used to detect the hydraulic oil temperature in the hydraulic oil main pipeline.

5. The hydraulic control system for the concrete placing equipment as described in claim 4, characterized in that, The main pipeline temperature sensor is located at the end of the main hydraulic pipeline away from the hydraulic oil tank; or, the circulation pipeline is connected to the ends of the main hydraulic pipeline and the return pipeline away from the hydraulic oil tank, and the main pipeline temperature sensor is located on the circulation pipeline.

6. The hydraulic control system for the concrete placing equipment as described in claim 1, characterized in that, The hydraulic actuators are multiple, and the multiple hydraulic actuators are arranged in parallel in sequence; the main hydraulic pressure pipeline and the main return pipeline are respectively connected to the multiple hydraulic actuators, and the end of the main hydraulic pressure pipeline and the end of the main return pipeline are connected to the last hydraulic actuator; the circulation pipeline is connected to the end of the main hydraulic pressure pipeline and the end of the main return pipeline.

7. The hydraulic control system for the concrete placing equipment as described in claim 1, characterized in that, The hydraulic control system of the concrete placing equipment also includes a pressure detection unit and an overflow valve. The pressure detection unit is used to detect the operating load pressure of the hydraulic cylinder and the outlet pressure of the oil supply pump unit. The inlet of the overflow valve is connected to the main oil pressure pipeline, and the outlet of the overflow valve is connected to the main oil return pipeline. The control unit is also connected to the pressure detection unit and the overflow valve signal, and the control unit is also used to control the overflow setting value of the overflow valve according to the pressure signal detected by the pressure detection unit and the oil temperature information detected by the oil temperature detection unit.

8. The hydraulic control system for the concrete placing equipment as described in claim 1, characterized in that, The main directional valve is a proportional directional valve, and the control unit is also signal-connected to the main directional valve and the oil supply pump unit; the control unit is also used to control the opening degree of the main directional valve and the oil supply flow rate of the oil supply pump unit according to the hydraulic oil demand flow rate of the boom movement.

9. A control method for a hydraulic control system of a concrete placing equipment as described in any one of claims 1-8, characterized in that, The control method includes: When the oil temperature detection unit detects that the hydraulic oil temperature in the main hydraulic pipeline is lower than the set value or the hydraulic oil temperature in the hydraulic oil tank, the control unit controls the switch valve to open and the radiator to close, so that the hydraulic oil in the hydraulic oil tank is circulated back to the hydraulic oil tank through the main hydraulic pipeline, the circulation pipeline and the return oil pipeline in sequence. When the oil temperature detection unit detects that the hydraulic oil temperature in the hydraulic oil tank is higher than the control value, the control unit controls the opening of both the switching valve and the radiator, so that the hydraulic oil in the hydraulic oil tank circulates back to the hydraulic oil tank in sequence through the main pressure pipeline, the circulation pipeline, the return oil main pipeline and the radiator.

10. A concrete placing device, characterized in that, The hydraulic control system for a concrete placing equipment as described in any one of claims 1-8 is provided, wherein the hydraulic cylinder and control valve group in each hydraulic actuator are mounted on the boom of the concrete placing equipment; there are multiple hydraulic actuators, which are arranged in parallel in sequence, and the main hydraulic oil pipeline and the main return oil pipeline are respectively connected to the multiple hydraulic actuators.

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