Hydraulic system, engineering machinery and engineering machinery horizontal pushing control method

Abstract

The invention belongs to the technical field of engineering machinery, and discloses a hydraulic system, engineering machinery and an engineering machinery horizontal pushing control method.In the hydraulic system, when an additional valve is in a first initial state, a first oil port and a second oil port are disconnected, and at the moment, an oil cylinder is controlled to supply oil or return oil only through an oil supply system; when the additional valve is in the first working state, the first oil port communicates with the second oil port, the additional valve is configured to only allow oil to flow from the first oil port to the second oil port, at the moment, when the oil cylinder is controlled to retract, oil in the rodless cavity can flow to the rod cavity through the first oil port and the second oil port in sequence, and therefore flow regeneration is achieved; the control oil cylinder can be kept in an extending state; when the additional valve is in the second working state, the first oil port is communicated with the second oil port, the oil can freely flow between the rodless cavity and the rod cavity at the moment, and when the control oil cylinder retracts, flow regeneration can be achieved, and the control oil cylinder can freely float.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, and in particular to hydraulic systems, engineering machinery, and methods for controlling the horizontal thrust of engineering machinery. Background Technology

[0002] In addition to digging, front shovel hydraulic excavators also require pushing operations. During pushing, the stick cylinder extends to move the stick relative to the boom. Simultaneously, the boom cylinder moves the boom with small movements, and the bucket cylinder moves the bucket with small movements to bring the bucket teeth into contact with the ground. In other words, pushing requires the coordinated operation of the stick, boom, and bucket cylinders. The operator must simultaneously operate all three cylinders and rely solely on visual inspection to determine whether the bucket teeth are in contact with the ground, making operation difficult and resulting in poor pushing performance.

[0003] In response, the relevant technology provides a hydraulic control system in which the main control valve, in addition to supplying oil to the rod or rodless chamber of the boom cylinder, also has a regeneration and floating state. When the main control valve is in this state, the oil in the rodless chamber and the rod chamber of the boom cylinder are connected to form an oil circuit circulation. When the boom is lowered, under the action of gravity, some of the hydraulic oil in the rodless chamber can enter the rod chamber to achieve flow regeneration. At the same time, during the flat pushing operation, the boom cylinder can freely extend and retract according to the terrain, reducing the operator's operating intensity. However, there are two problems. First, due to the characteristics of excavators, they often use 3-way or 4-way universal multi-way valves as hydraulic control valves. The main control valve of the hydraulic control system usually needs to be integrated into the multi-way valve, which requires changing the structure of the multi-way valve and related oil circuits. This makes the structure of the multi-way valve more complex and increases the installation difficulty. Second, in some working conditions, the boom needs to be supported by the bucket after it is lowered, and the boom no longer needs to float freely. The hydraulic control system can achieve this by cutting off the oil supply and return lines, but flow regeneration cannot be achieved during the boom lowering process. Summary of the Invention

[0004] According to one aspect of the invention, a hydraulic system is provided that allows the boom to float freely during a horizontal pushing operation of construction machinery without increasing installation difficulty. Furthermore, in situations where the bucket needs to be supported on the ground, flow regeneration can be achieved during the lowering of the boom.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A hydraulic system includes an oil supply system and a control cylinder, wherein the control cylinder is a boom cylinder for controlling the rotation of the boom relative to a turntable or a stick cylinder for controlling the rotation of the stick relative to the boom; the control cylinder has a rodless chamber and a rod chamber, and the oil supply system is used to supply oil to the rodless chamber or the rod chamber; the hydraulic system further includes an auxiliary valve, the auxiliary valve having a first port communicating with the rodless chamber and a second port communicating with the rod chamber, the auxiliary valve having a first initial state, a first working state, and a second working state; when the auxiliary valve is in the first initial state, the first port is disconnected from the second port; when the auxiliary valve is in the first working state, the first port is connected to the second port, and the auxiliary valve is configured to allow oil to flow only from the first port to the second port; when the auxiliary valve is in the second working state, the first port is connected to the second port.

[0007] As a preferred embodiment of the hydraulic system, a back pressure valve is also included. The auxiliary valve further has a third oil port connected to the inlet end of the back pressure valve. When the auxiliary valve is in a first initial state, the first oil port, the second oil port, and the third oil port are all disconnected. When the auxiliary valve is in a first working state, the first oil port and the third oil port are connected. When the auxiliary valve is in a second working state, the first oil port, the second oil port, and the third oil port are connected simultaneously.

[0008] As a preferred embodiment of the hydraulic system, a back pressure valve pressure regulating mechanism is also included, which is used to adjust the back pressure of the back pressure valve.

[0009] As a preferred embodiment of the hydraulic system, the oil supply system includes an oil tank, an oil supply pump, and a control valve. The input end of the oil supply pump is connected to the inner cavity of the oil tank. The control valve has a first working port, a second working port, a third working port, and a fourth working port. The first working port is connected to the output end of the oil supply pump, the second working port is connected to the inner cavity of the oil tank, the third working port is connected to the rodless chamber, and the fourth working port is connected to the rod chamber. The control valve has a second initial state, a third working state, and a fourth working state. When the control valve is in the second initial state, the first working port, the second working port, the third working port, and the fourth working port are all disconnected. When the control valve is in the third working state, the first working port is connected to the third working port, and the second working port is connected to the fourth working port. When the control valve is in the fourth working state, the first working port is connected to the fourth working port, and the second working port is connected to the third working port.

[0010] According to another aspect of the invention, an engineering machine is provided, comprising the aforementioned hydraulic system, and further comprising a turntable, a boom rotatably connected to the turntable, a stick rotatably connected to the boom, and a bucket rotatably connected to the stick.

[0011] According to another aspect of the present invention, a method for controlling the horizontal thrust of engineering machinery is provided, which is implemented through the above-mentioned hydraulic system, wherein the control cylinder is a boom cylinder;

[0012] The engineering machinery horizontal thrust control method includes:

[0013] S110: Confirm that the construction machinery is in a horizontal pushing operation state;

[0014] S120: Ensure the bucket teeth are in contact with the ground;

[0015] S130: Control the auxiliary valve to be in the second working state;

[0016] S140: Perform a horizontal pushing operation;

[0017] S150: Determine that the bucket has been pushed to the maximum horizontal pushing position;

[0018] S160: Control the auxiliary valve to be in the first working state, and control the engineering machinery to exit the horizontal pushing working state.

[0019] As a preferred embodiment of the horizontal thrust control method for engineering machinery, the hydraulic system further includes a back pressure valve, and the auxiliary valve also has a third oil port connected to the inlet end of the back pressure valve. When the auxiliary valve is in a first initial state, the first oil port, the second oil port, and the third oil port are all disconnected; when the auxiliary valve is in a first working state, the first oil port and the third oil port are connected; when the auxiliary valve is in a second working state, the first oil port, the second oil port, and the third oil port are simultaneously connected.

[0020] The engineering machinery horizontal thrust control method also includes the following steps executed synchronously with step S130:

[0021] S131: Adjust the back pressure of the back pressure valve to the first back pressure;

[0022] The engineering machinery horizontal thrust control method also includes the following steps executed synchronously with step S160:

[0023] S161: Adjust the back pressure of the back pressure valve to a second back pressure, wherein the second back pressure is greater than the first back pressure.

[0024] As a preferred embodiment of the horizontal thrust control method for engineering machinery, step S120 includes:

[0025] S1201: Control the boom to descend;

[0026] S1202: Detect the pressure in the rodless chamber of the boom cylinder;

[0027] S1203: Compare the pressure in the rodless cavity with the preset pressure;

[0028] If the pressure in the rodless cavity is less than the preset pressure, then step S130 is executed.

[0029] As a preferred embodiment of the engineering machinery horizontal thrust control method, the engineering machinery horizontal thrust control method further includes step S111 located between step S110 and step S120;

[0030] S111: Determine that the boom cylinder has been retracted to its minimum length;

[0031] Step S140 includes: controlling the extension of the boom cylinder;

[0032] Step S150 includes: detecting the length of the boom cylinder; determining whether the boom cylinder has been extended to its maximum length; if the boom cylinder has been extended to its maximum length, then determining that the bucket has been pushed to the maximum horizontal position, and proceeding to step S160.

[0033] As a preferred embodiment of the horizontal thrust control method for engineering machinery, the hydraulic system further includes a bucket cylinder, one end of which is rotatably connected to the boom and the other end of which is rotatably connected to the bucket.

[0034] The engineering machinery horizontal thrust control method also includes step S1101, which is located between step S110 and step S111;

[0035] S1101: Determine that the effective length of the bucket cylinder is equal to the preset length;

[0036] Wherein, the effective length of the bucket cylinder is the distance between the rotation center of the bucket cylinder and the boom and the rotation center of the bucket cylinder and the bucket; the preset length is the distance between the rotation center of the boom and the stick and the rotation center of the stick and the bucket.

[0037] The beneficial effects of this invention are:

[0038] This invention provides a hydraulic system, including an oil supply system and a control cylinder. The control cylinder is either a boom cylinder for controlling the rotation of the boom relative to a turntable or a stick cylinder for controlling the rotation of the stick relative to the boom. The control cylinder has a rodless chamber and a rod chamber. The oil supply system supplies oil to the rodless chamber or the rod chamber, thereby extending or retracting the control cylinder. The hydraulic system also includes an auxiliary valve, which has a first port communicating with the rodless chamber and a second port communicating with the rod chamber. The auxiliary valve has a first initial state, a first working state, and a second working state. When the auxiliary valve is in the first initial state, the first port and the second port are disconnected. At this time, the control cylinder is only supplied or returned oil through the oil supply system to extend or retract the control cylinder. When the auxiliary valve is in the first working state, the first port and the second port are connected, and the auxiliary valve is configured to allow oil to flow only from the first port to the second port. At this time, when the control cylinder retracts, the oil in the rodless chamber can... The fluid flows through the first and second oil ports to the rod chamber, thus achieving flow regeneration. Furthermore, since the fluid cannot flow from the second port to the first port (i.e., cannot flow from the rod chamber to the rodless chamber), the control cylinder can remain extended. When the control cylinder is a boom cylinder, it can provide ground support. When the auxiliary valve is in its second operating state, the first and second oil ports are connected, allowing the fluid to flow freely between the rodless and rod chambers. Flow regeneration is achieved when the control cylinder retracts, and the control cylinder can also float freely. When the control cylinder is a boom cylinder, it facilitates actions such as pushing. This hydraulic system can simultaneously achieve ground support and flow regeneration, or simultaneously achieve floating and flow regeneration. Moreover, since this hydraulic system is based on the oil supply system and control cylinder with an additional valve, it does not require changes to the original multi-way valve structure and related pipelines, resulting in lower installation difficulty.

[0039] The present invention also provides engineering machinery, including the above-mentioned hydraulic system, and further including a turntable, a boom rotatably connected to the turntable, a stick rotatably connected to the boom, and a bucket rotatably connected to the stick. The hydraulic system can simultaneously achieve ground support and flow regeneration, or simultaneously achieve floating and flow regeneration. In addition, since the hydraulic system is based on the oil supply system and control cylinder with additional valves, it does not need to change the original structure of the multi-way valve and related pipelines, and the later installation difficulty is low.

[0040] This invention also provides a method for controlling the horizontal thrust of construction machinery, implemented through the aforementioned hydraulic system, with the control cylinder being the boom cylinder. In this method, the construction machinery is determined to be in a horizontal thrust working state, and the bucket teeth are determined to be in contact with the ground. At this time, the bucket can remain firmly in contact with the ground under gravity, and the boom does not need to move. Therefore, the auxiliary valve is controlled to be in a second working state, allowing the hydraulic fluid to flow freely between the rodless and rod chambers. This enables flow regeneration during boom descent and allows the boom cylinder to float freely. The horizontal thrust can then be performed via operator control or automatic control. Once the bucket has been pushed to its maximum horizontal thrust position, the boom needs to be raised again. Therefore, the auxiliary valve is controlled to be in a first working state, and the construction machinery is controlled to exit the horizontal thrust working state, preventing hydraulic fluid from flowing from the second port to the first port. The boom can be lifted by extending the boom cylinder. Furthermore, flow regeneration can be achieved during subsequent boom descent. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the hydraulic system in an embodiment of the present invention;

[0042] Figure 2 This is a partial structural diagram of the hydraulic system in an embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of the structure of the engineering machinery in an embodiment of the present invention;

[0044] Figure 4 This is the first flowchart of the engineering machinery horizontal thrust control method in the embodiment of the present invention;

[0045] Figure 5 This is the second flowchart of the engineering machinery horizontal push control method in the embodiment of the present invention.

[0046] In the picture:

[0047] 100. Turntable; 110. Boom; 120. Stick; 130. Bucket;

[0048] 1. Fuel supply system; 11. Fuel tank; 12. Fuel pump; 13. Control valve;

[0049] 2. Boom cylinder; 21. Rodless chamber; 22. Rod chamber;

[0050] 3. Stalk cylinder; 31. Stalk cylinder hydraulic circuit;

[0051] 4. Additional valve; 41. First oil port; 42. Second oil port; 43. Third oil port;

[0052] 5. Back pressure valve;

[0053] 6. Back pressure valve pressure regulating mechanism; 61. Pilot valve;

[0054] 7. Valve block;

[0055] 8. Bucket hydraulic cylinder. Detailed Implementation

[0056] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0057] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0058] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0059] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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 limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0060] Example 1

[0061] To facilitate the horizontal pushing operation of excavators, a hydraulic control system has been developed. Its main control valve, in addition to supplying oil to the rod or rodless chamber of the boom cylinder, also has regeneration and floating states. When the main control valve is in this state, the oil in the rodless and rod chambers of the boom cylinder is connected, forming an oil circulation circuit. When the boom is lowered, under gravity, some hydraulic oil from the rodless chamber can enter the rod chamber, achieving flow regeneration. Simultaneously, during horizontal pushing operations, the boom cylinder can freely extend and retract according to the terrain, reducing the operator's workload. However, this system presents two problems. First, it requires changes to the structure of the multi-way valve and related oil circuits, leading to a more complex valve structure and increased installation difficulty. Second, in some operating conditions, the boom needs to be supported by the bucket after lowering, eliminating the need for free floating. This hydraulic control system can achieve this by cutting off the oil supply and return lines, but flow regeneration cannot be achieved during boom lowering.

[0062] Reference Figures 1-2The hydraulic system includes an oil supply system 1 and a control cylinder. The control cylinder is either a boom cylinder 2 for controlling the rotation of the boom 110 relative to the turntable 100 or a stick cylinder 3 for controlling the rotation of the stick 120 relative to the boom 110. The control cylinder has a rodless chamber 21 and a rod chamber 22. The oil supply system 1 is used to supply oil to the rodless chamber 21 or the rod chamber 22, thereby extending or retracting the control cylinder. The hydraulic system also includes an auxiliary valve 4, which has a first port 41 communicating with the rodless chamber 21 and a second port 42 communicating with the rod chamber 22. The auxiliary valve 4 has a first initial state, a first working state, and a second working state. When the auxiliary valve 4 is in the first initial state, the first port 41 and the second port 42 are disconnected. At this time, the control cylinder is supplied or returned oil only through the oil supply system 1 to extend or retract the control cylinder. When the auxiliary valve 4 is in the first working state, the first port 41 and the second port 42 are connected, and the auxiliary valve 4 is configured to allow oil to flow only from the first port 41 to the second port 42. At this time, when the control cylinder retracts, the oil in the rodless chamber 21 can... The fluid flows sequentially through the first port 41 and the second port 42 to the rod chamber 22, thereby achieving flow regeneration. Furthermore, since the fluid cannot flow from the second port 42 to the first port 41, i.e., cannot flow from the rod chamber 22 to the rodless chamber 21, the control cylinder can remain extended. When the control cylinder is the boom cylinder 2, it can provide ground support. When the auxiliary valve 4 is in its second operating state, the first port 41 and the second port 42 are connected, allowing the fluid to flow freely between the rodless chamber 21 and the rod chamber 22. Flow regeneration is achieved when the control cylinder retracts, and the control cylinder can also float freely. When the control cylinder is the boom cylinder 2, it facilitates actions such as pushing. This hydraulic system can simultaneously achieve ground support and flow regeneration, or simultaneously achieve floating and flow regeneration. Moreover, since this hydraulic system is based on the oil supply system 1 and the control cylinder with the auxiliary valve 4 added, there is no need to change the original multi-way valve structure and related pipelines, making subsequent installation easier.

[0063] In this embodiment, the hydraulic system is applied to an excavator, and the control cylinder is the boom cylinder 2. In other embodiments, the control cylinder can also be the stick cylinder 3 of the excavator, or the hydraulic system can be applied to a loader, and the control cylinder can be the boom cylinder 2 of the loader.

[0064] Among them, the auxiliary valve 4 is a solenoid valve, and has an initial position, a first right position and a second right position. When the auxiliary valve 4 is in the initial position, the auxiliary valve 4 is in the first initial state; when the auxiliary valve 4 is in the first right position, the auxiliary valve 4 is in the first working state; when the auxiliary valve 4 is in the second right position, the auxiliary valve 4 is in the second working state. The state of the auxiliary valve 4 can be changed by controlling the position of the valve core of the auxiliary valve 4.

[0065] Continue to refer to Figures 1-2The hydraulic system also includes a back pressure valve 5, and an auxiliary valve 4 has a third port 43 connected to the inlet end of the back pressure valve 5. When the auxiliary valve 4 is in the first initial state, the first port 41, the second port 42, and the third port 43 are disconnected. When the auxiliary valve 4 is in the first working state, the first port 41 and the third port 43 are connected, so that when the pressure in the rodless chamber 21 is too high, a portion of the oil can flow through the first port 41 to the second port 42 and then into the rod chamber 22, while another portion of the oil can flow through the first port 41 and the third port 43 to the back pressure valve 5 and be released through the back pressure valve 5, thereby ensuring that the oil pressure in the oil circuit where the rodless chamber 21 is located is not too high. When the auxiliary valve 4 is in the second working state, the first oil port 41, the second oil port 42 and the third oil port 43 are connected at the same time. So when the pressure in the rodless chamber 21 or the rod chamber 22 is too high, the oil can flow through the first oil port 41 or the second oil port 42 to the third oil port 43, and then to the back pressure valve 5, and be released through the back pressure valve 5, thereby ensuring that the oil pressure in the oil circuit where the rodless chamber 21 and the rod chamber 22 are located will not be too high.

[0066] Continue to refer to Figures 1-2 The hydraulic system also includes a back pressure valve pressure regulating mechanism 6, which is used to adjust the back pressure of the back pressure valve 5. The back pressure of the back pressure valve 5 can be adjusted according to actual needs. In this embodiment, the back pressure valve pressure regulating mechanism 6 includes a pilot valve 61, which is specifically a solenoid valve. When the pilot valve 61 is energized, it can direct the oil from the pilot oil source to the back pressure regulating module of the back pressure valve 5 to regulate the back pressure of the back pressure valve 5. The pilot valve 61 is a relatively conventional technology in the field, and its specific structure and back pressure regulation principle will not be described in detail.

[0067] Continue to refer to Figures 1-2The oil supply system 1 includes an oil tank 11, an oil supply pump 12, and a control valve 13. The outlet end of the back pressure valve 5 is connected to the inner cavity of the oil tank 11, and the input end of the oil supply pump 12 is connected to the inner cavity of the oil tank 11. The control valve 13 has a first working port, a second working port, a third working port, and a fourth working port. The first working port is connected to the output end of the oil supply pump 12, the second working port is connected to the inner cavity of the oil tank 11, the third working port is connected to the rodless chamber 21, and the fourth working port is connected to the rod chamber 22. The control valve 13 has a second initial state, a third working state, and a fourth working state. When the control valve 13 is in the second initial state, the first working port, the second working port, the third working port, and the fourth working port are all disconnected. Optionally, at this time, the output end of the oil supply pump 12 is directly connected to the inner cavity of the oil tank 11, and no oil supply or return is performed. When the control valve 13 is in the third working state, the first working port is connected to the third working port, and the second working port is connected to the fourth working port. At this time, oil can be supplied to the rodless chamber 21 through the oil supply pump 12. At the same time, the oil in the rod chamber 22 can flow back to the oil tank 11, thereby causing the control cylinder to extend. When the control valve 13 is in the fourth working state, the first working port is connected to the fourth working port, and the second working port is connected to the third working port. Oil can be supplied to the rod chamber 22 through the oil supply pump 12. At the same time, the oil in the rodless chamber 21 can flow back to the oil tank 11, thereby causing the control cylinder to retract.

[0068] Among them, the control valve 13 is a solenoid valve and has a left position, a middle position and a right position. When the control valve 13 is in the middle position, the control valve 13 is in the second initial state; when the control valve 13 is in the left position, the control valve 13 is in the fourth working state; when the control valve 13 is in the right position, the control valve 13 is in the third working state. The state of the control valve 13 can be changed by controlling the position of the valve core of the control valve 13.

[0069] Continue to refer to Figures 1-2 The hydraulic system also includes a valve block 7, on which the auxiliary valve 4 and the back pressure valve 5 are both mounted, thus integrating the auxiliary valve 4 and the back pressure valve 5 and further simplifying the overall installation. Optionally, the back pressure valve pressure regulating mechanism 6 is also mounted on the valve block 7.

[0070] Example 2

[0071] This embodiment provides construction machinery, including the hydraulic system described in Embodiment 1 above. Specifically, this construction machinery can be an excavator, or alternatively, a loader. (Refer to...) Figure 3The construction machinery also includes a turntable 100, a boom 110 rotatably connected to the turntable 100, a stick 120 rotatably connected to the boom 110, and a bucket 130 rotatably connected to the stick 120. The hydraulic system can simultaneously achieve ground support and flow regeneration, or simultaneously achieve floating and flow regeneration. In addition, since the hydraulic system is based on the oil supply system 1 and the control cylinder with an additional valve 4, there is no need to change the original structure of the multi-way valve and related pipelines, making the later installation less difficult.

[0072] Example 3

[0073] This embodiment provides a method for controlling the horizontal thrust of construction machinery. It is implemented using the construction machinery described in Embodiment 2 above. The control cylinder is boom cylinder 2. In this embodiment, the construction machinery is a front shovel excavator.

[0074] Reference Figures 4-5 The control method for horizontal pushing of engineering machinery includes the following steps.

[0075] S110: Confirm that the construction machinery is in a horizontal pushing working state.

[0076] Specifically, a push-operation button is installed in the cab. When the driver presses the push-operation button, the controller receives the relevant information and controls the construction machinery to enter the push-operation state.

[0077] S120: Ensure that the teeth of bucket 130 are in contact with the ground.

[0078] After the bucket teeth of the bucket 130 are in contact with the ground, the bucket 130 can stick to the ground under the action of gravity, and the boom 110 does not need to move.

[0079] Step S120 specifically includes the following steps.

[0080] S1201: Control the boom 110 to descend.

[0081] Specifically, the boom 110 can be lowered by the operator. In addition, the controller can send a signal to the control valve 13 to put it into a fourth working state so that the boom cylinder 2 retracts, thereby controlling the boom 110 to lower.

[0082] S1202: Detect the pressure in the rodless chamber 21 of the boom cylinder 2.

[0083] The pressure in the rodless chamber 21 of the boom cylinder 2 can be obtained by a pressure sensor installed in the rodless chamber 21 of the boom cylinder 2 or in the pipeline connected to it.

[0084] S1203: Compare the pressure in rodless chamber 21 with the preset pressure.

[0085] During the descent of the boom 110 and before the bucket 130 touches the ground, the weight of the boom 110 is mainly borne by the boom cylinder 2, resulting in a relatively high pressure in the rodless chamber 21. However, after the bucket 130 touches the ground, the weight of the boom 110 is shared by the boom cylinder 2, the stick 120, the bucket 130, and other structures, causing the pressure in the rodless chamber 21 to drop rapidly.

[0086] If the pressure in the rodless chamber 21 is less than the preset pressure, it indicates that the pressure in the rodless chamber 21 is relatively low, indicating that the bucket 130 has contacted the ground, and therefore step S130 is executed.

[0087] S130: Control auxiliary valve 4 to be in the second working state.

[0088] When the auxiliary valve 4 is in the second working state, the oil can flow freely between the rodless chamber 21 and the rod chamber 22, which can realize flow regeneration when the boom 110 descends, and also allow the boom cylinder 2 to float freely.

[0089] The engineering machinery horizontal thrust control method also includes step S131, which is executed synchronously with step S130.

[0090] S131: Adjust the back pressure of back pressure valve 5 to the first back pressure.

[0091] The first back pressure can be set according to the actual situation, and it is generally small, so that the oil in the rodless chamber 21 and the rod chamber 22 can flow back to the oil tank 11 freely, thus achieving floating.

[0092] S140: Perform a horizontal push operation.

[0093] The horizontal movement can be operated by a driver or controlled automatically.

[0094] S150: Confirm that bucket 130 has been pushed to the maximum horizontal position.

[0095] After the bucket 130 has been pushed to the maximum horizontal position, the boom 110 needs to be raised again to perform subsequent operations.

[0096] S160: Controls auxiliary valve 4 to be in the first working state and controls the construction machinery to exit the horizontal pushing working state.

[0097] This step prevents the oil from flowing from the second port 42 to the first port 41. The boom 110 can be lifted by extending the boom cylinder 2. In addition, flow regeneration can be achieved when the boom 110 descends.

[0098] The engineering machinery horizontal thrust control method also includes step S161, which is executed synchronously with step S160.

[0099] S161: Adjust the back pressure of the back pressure valve 5 to the second back pressure, where the second back pressure is greater than the first back pressure.

[0100] The second back pressure can be set according to the actual situation. Adjusting the back pressure of the back pressure valve 5 to the second back pressure can ensure that the oil circuit where the inlet end of the back pressure valve 5, i.e. the rodless chamber 21 is located, maintains a certain oil pressure, which can assist in flow regeneration when the boom 110 descends.

[0101] Optionally, the hydraulic system also includes a bucket cylinder 8, one end of which is rotatably connected to the boom 110 and the other end is rotatably connected to the bucket 130, thereby forming a four-bar linkage between the boom 110, stick 120, bucket 130 and bucket cylinder 8. At this time, the movement of the bucket 130 can be controlled by controlling the movement of the stick 120. At the same time, when pushing horizontally, since the bucket 130 is in contact with the ground and the boom 110 can float freely, the bucket 130 can be kept close to the ground under its own weight.

[0102] The engineering machinery horizontal push control method also includes step S111, which is located between steps S110 and S120.

[0103] S111: Confirm that boom cylinder 3 has been retracted to its minimum length.

[0104] Specifically, step S111 includes: detecting the length of the boom cylinder 3; determining whether the boom cylinder 3 has been retracted to its minimum length; if the boom cylinder 3 has been retracted to its minimum length, then it is determined that the boom cylinder 3 has been retracted to its minimum length, and thus step S120 is executed.

[0105] Step S140 includes: controlling the extension of the boom cylinder 3.

[0106] The stick 120 can be controlled to move by extending the stick cylinder 3, which in turn drives the bucket 130 to move.

[0107] Step S150 includes: detecting the length of the boom cylinder 3; determining whether the boom cylinder 3 has been extended to its maximum length; if the boom cylinder 3 has been extended to its maximum length, then it is determined that the bucket 130 has been pushed to the maximum horizontal position, and thus step S160 is executed.

[0108] The engineering machinery horizontal thrust control method also includes step S1101, which is located between step S110 and step S111.

[0109] S1101: Determine that the effective length of the bucket cylinder 8 is equal to the preset length.

[0110] The effective length of the bucket cylinder 8 is the distance between the rotation center of the bucket cylinder 8 and the boom 110 and the rotation center of the bucket cylinder 8 and the bucket 130; the preset length is the distance between the rotation center of the boom 110 and the stick 120 and the rotation center of the stick 120 and the bucket 130.

[0111] Through step S1101, before the boom 110 is lowered, the four-bar linkage formed by the boom 110, stick 120, bucket 130, and bucket cylinder 8 is made into a parallelogram shape, such as... Figure 3 As shown, during the subsequent horizontal pushing process, since the bucket 130 remains close to the ground, the boom 110 remains basically still. The stick 120 is controlled by extending the stick cylinder 3. At this time, the rotation angle of the stick 120 is consistent with the rotation angle of the bucket cylinder 8, which makes the forward horizontal pushing action of the bucket 130 more stable and smooth.

[0112] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A hydraulic system comprising an oil supply system (1) and control cylinders, said control cylinders being either a boom cylinder (2) for controlling the rotation of a boom (110) relative to a turntable (100) or a stick cylinder (3) for controlling the rotation of a stick (120) relative to the boom (110); said control cylinders having a rodless chamber (21) and a rod chamber (22), said oil supply system (1) for supplying oil to said rodless chamber (21) or said rod chamber (22); characterized in that, The hydraulic system further includes an auxiliary valve (4), which has a first port (41) communicating with the rodless chamber (21) and a second port (42) communicating with the rod chamber (22). The auxiliary valve (4) has a first initial state, a first working state, and a second working state. When the auxiliary valve (4) is in the first initial state, the first port (41) and the second port (42) are disconnected. When the auxiliary valve (4) is in the first working state, the first port (41) and the second port (42) are connected, and the auxiliary valve (4) is configured to allow oil to flow only from the first port (41) to the second port (42). When the auxiliary valve (4) is in the second working state, the first port (41) and the second port (42) are connected.

2. The hydraulic system according to claim 1, characterized in that, It also includes a back pressure valve (5), and the auxiliary valve (4) also has a third oil port (43) connected to the inlet end of the back pressure valve (5). When the auxiliary valve (4) is in the first initial state, the first oil port (41), the second oil port (42) and the third oil port (43) are disconnected from each other. When the auxiliary valve (4) is in the first working state, the first oil port (41) and the third oil port (43) are connected. When the auxiliary valve (4) is in the second working state, the first oil port (41), the second oil port (42) and the third oil port (43) are connected simultaneously.

3. The hydraulic system according to claim 2, characterized in that, It also includes a back pressure valve pressure regulating mechanism (6), which is used to adjust the back pressure of the back pressure valve (5).

4. The hydraulic system according to any one of claims 1-3, characterized in that, The oil supply system (1) includes an oil tank (11), an oil pump (12), and a control valve (13). The input end of the oil pump (12) is connected to the inner cavity of the oil tank (11). The control valve (13) has a first working port, a second working port, a third working port, and a fourth working port. The first working port is connected to the output end of the oil pump (12), the second working port is connected to the inner cavity of the oil tank (11), the third working port is connected to the rodless chamber (21), and the fourth working port is connected to the rod chamber (22). The control valve (13) has a first working port, a second working port, a third working port, and a fourth working port. There are three initial states, a third working state, and a fourth working state. When the control valve (13) is in the second initial state, the first working port, the second working port, the third working port, and the fourth working port are all disconnected. When the control valve (13) is in the third working state, the first working port is connected to the third working port, and the second working port is connected to the fourth working port. When the control valve (13) is in the fourth working state, the first working port is connected to the fourth working port, and the second working port is connected to the third working port.

5. Construction machinery, characterized in that, The system includes the hydraulic system as described in any one of claims 1-4, and further includes a turntable (100), a boom (110) rotatably connected to the turntable (100), a stick (120) rotatably connected to the boom (110), and a bucket (130) rotatably connected to the stick (120).

6. A method for controlling the horizontal movement of engineering machinery, characterized in that, In the engineering machinery implementation as described in claim 5, the control cylinder is a boom cylinder (2); The engineering machinery horizontal thrust control method includes: S110: Confirm that the construction machinery is in a horizontal pushing operation state; S120: Ensure that the teeth of the bucket (130) are in contact with the ground; S130: Control the auxiliary valve (4) to be in the second working state; S140: Perform a horizontal pushing operation; S150: Determine that the bucket (130) has been pushed to the maximum horizontal pushing position; S160: Control the auxiliary valve (4) to be in the first working state, and control the engineering machinery to exit the flat push working state.

7. The engineering machinery horizontal thrust control method according to claim 6, characterized in that, The hydraulic system also includes a back pressure valve (5), and the auxiliary valve (4) also has a third oil port (43) connected to the inlet end of the back pressure valve (5). When the auxiliary valve (4) is in the first initial state, the first oil port (41), the second oil port (42) and the third oil port (43) are disconnected from each other. When the auxiliary valve (4) is in the first working state, the first oil port (41) and the third oil port (43) are connected. When the auxiliary valve (4) is in the second working state, the first oil port (41), the second oil port (42) and the third oil port (43) are connected simultaneously. The engineering machinery horizontal thrust control method also includes the following steps executed synchronously with step S130: S131: Adjust the back pressure of the back pressure valve (5) to the first back pressure; The engineering machinery horizontal thrust control method also includes the following steps executed synchronously with step S160: S161: Adjust the back pressure of the back pressure valve (5) to a second back pressure, wherein the second back pressure is greater than the first back pressure.

8. The engineering machinery horizontal thrust control method according to claim 6, characterized in that, Step S120 includes: S1201: Control the boom (110) to descend; S1202: Detect the pressure in the rodless chamber (21) of the boom cylinder (2); S1203: Compare the pressure in the rodless cavity (21) with the preset pressure; If the pressure in the rodless cavity (21) is less than the preset pressure, then step S130 is executed.

9. The engineering machinery horizontal thrust control method according to claim 6, characterized in that, The engineering machinery horizontal thrust control method also includes step S111, which is located between step S110 and step S120; S111: Determine that the boom cylinder (3) has been retracted to its minimum length; Step S140 includes: controlling the extension of the boom cylinder (3); Step S150 includes: detecting the length of the boom cylinder (3); determining whether the boom cylinder (3) has been extended to its maximum length; if the boom cylinder (3) has been extended to its maximum length, then it is determined that the bucket (130) has been pushed to the maximum horizontal position, and step S160 is executed.

10. The engineering machinery horizontal thrust control method according to claim 9, characterized in that, The hydraulic system also includes a bucket cylinder (8), one end of which is rotatably connected to the boom (110) and the other end is rotatably connected to the bucket (130); The engineering machinery horizontal thrust control method also includes step S1101, which is located between step S110 and step S111; S1101: Determine that the effective length of the bucket cylinder (8) is equal to the preset length; The effective length of the bucket cylinder (8) is the distance between the rotation center of the bucket cylinder (8) and the boom (110) and the rotation center of the bucket cylinder (8) and the bucket (130); the preset length is the distance between the rotation center of the boom (110) and the stick (120) and the rotation center of the stick (120) and the bucket (130).

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