Telescopic arm extension control method and hydraulic control system, and telescopic operation equipment

Abstract

The present invention belongs to the technical field of engineering machinery and provides a telescopic arm extension control method, a hydraulic control system thereof, and telescopic operation equipment. The telescopic arm extension control method includes: collecting telescopic arm operating condition information and telescopic cylinder piston rod extension length information; calculating a safety limit pressure for the telescopic cylinder to ensure safe operation under the current operating conditions based on the operating condition information and the piston rod extension length information; and setting the relief pressure of the telescopic cylinder extension relief valve group based on the safety limit pressure. By setting the relief pressure of the telescopic cylinder extension relief valve group to the safety limit pressure, the system pressure oil can be overflowed when the oil pressure of the system reaches the safety limit pressure, thereby preventing the telescopic cylinder from being damaged due to overload and ensuring the safe operation of the telescopic cylinder.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering machinery, and in particular relates to a telescopic arm extension control method and a hydraulic control system and telescopic operation equipment. Background Art

[0002] Currently, there are two main ways to extend the multi-section telescopic boom of a crane: one is the multi-stage telescopic cylinder plus rope arrangement technology, and the other is the single-cylinder latch telescopic technology. Both methods involve the telescopic cylinder. The cylinder barrel and piston rod of the telescopic cylinder in the multi-stage telescopic cylinder plus rope arrangement structure are respectively fixed on different boom sections. The principle of the single-cylinder latch telescopic technology is that one end of the telescopic cylinder is fixed to the lower end of the basic arm, and the other end is provided with a latch mechanism. By connecting the latch mechanism to the target arm to be extended, and then pulling out the arm pin connecting the target arm to the previous level, the target arm and the other boom sections inside can be extended together. After reaching the preset position, the arm pin is released to fix the target arm to the previous boom section, and then the piston rod (cylinder) is controlled to retract separately, and the piston rod (cylinder) is connected to the latch mechanism of the previous boom section. Repeating the above steps can achieve the extension of the telescopic boom in sequence.

[0003] Existing telescopic cylinders have a fixed operating relief pressure for extension. However, the maximum thrust the cylinder can withstand varies depending on the telescopic boom's extended position, amplitude adjustment angle, and load. Sometimes, the cylinder reaches its thrust limit before the operating oil pressure reaches the relief pressure. If the relief valve is set to a fixed operating relief pressure, the cylinder can easily overload and damage it. Summary of the Invention

[0004] In response to the above-mentioned defects or shortcomings, the present invention provides a telescopic arm extension control method and its hydraulic control system, and telescopic operation equipment, aiming to avoid the telescopic cylinder from overloading.

[0005] To achieve the above object, the present invention provides a telescopic arm extension control method, the telescopic arm extension control method comprising:

[0006] S100: Collecting the working condition information of the telescopic arm and the extension length information of the piston rod of the telescopic cylinder;

[0007] S200: Calculating a safety limit pressure of the telescopic cylinder to ensure safe operation under the current working condition based on the working condition information and the extension length information of the piston rod;

[0008] S300: Setting the relief pressure of the extension relief valve group of the telescopic oil cylinder according to the safety limit pressure.

[0009] In an embodiment of the present invention, S200: calculating the safety limit pressure of the telescopic cylinder to ensure safe operation under the current working condition based on the working condition information and the extension length information of the piston rod specifically includes:

[0010] S210: Calculating the force deflection vector of the telescopic cylinder according to the working condition information;

[0011] S220: Calculating the theoretical maximum pressure that the telescopic cylinder can withstand under the current working condition based on the force deflection vector and the extended length information of the piston rod of the telescopic cylinder;

[0012] S230: Select a pressure value between the theoretical maximum pressure and the actual working pressure of the telescopic oil cylinder under the current working condition as a safety limit pressure.

[0013] In an embodiment of the present invention, the actual working pressure of the telescopic oil cylinder under the current working condition includes the working pressure of the telescopic oil cylinder at the current moment and the working pressure of the telescopic oil cylinder under the same working condition recorded in historical data.

[0014] In an embodiment of the present invention, after S300: setting the relief pressure of the extension relief valve group of the telescopic oil cylinder according to the safety limit pressure, the telescopic arm extension control method further includes:

[0015] S401: Confirm that the telescopic arm is extended normally;

[0016] S402: During the normal extension of the telescopic arm, the relief pressure of the extension relief valve group is adjusted in real time according to the change of the working condition of the telescopic arm and the change of the extension length of the piston rod until the telescopic arm is fully extended.

[0017] In an embodiment of the present invention, after S300: setting the relief pressure of the extension relief valve group of the telescopic oil cylinder according to the safety limit pressure, the telescopic arm extension control method further includes:

[0018] S411: Confirm that the telescopic arm is not extended normally;

[0019] S412: Check whether the working condition information is entered correctly.

[0020] In an embodiment of the present invention, if the input working condition information is incorrect, the telescopic arm extension control method further includes:

[0021] S413: Correcting the working condition information;

[0022] S414: recalculating the safety limit pressure according to the corrected working condition information;

[0023] S415: Reset the relief pressure of the extension relief valve group of the telescopic oil cylinder according to the recalculated safety limit pressure.

[0024] In an embodiment of the present invention, if the input working condition information is correct, the telescopic arm extension control method further includes:

[0025] S423: Check whether the telescopic arm has other abnormal conditions;

[0026] S424: If yes, process the abnormal situation, recalculate the safety limit pressure and reset the relief pressure of the extended relief valve group; if no, increase the relief pressure of the extended relief valve group.

[0027] In an embodiment of the present invention, the telescopic arm hydraulic control system includes:

[0028] Main oil circuit unit, including pressure oil circuit and return oil circuit;

[0029] The oil cylinder unit includes a telescopic oil cylinder and a rod chamber working oil circuit and a rodless chamber working oil circuit of the telescopic oil cylinder. The rod chamber working oil circuit and the rodless chamber working oil circuit are respectively connected to the pressure oil circuit and the return oil circuit through a reversing valve group;

[0030] The relief valve group is extended and arranged between the working oil circuit and the return oil circuit of the rodless chamber. The relief pressure of the relief valve group can be electrically controlled and adjusted; and

[0031] The controller is electrically connected to the extension relief valve group and is used to execute the telescopic arm extension control method described above.

[0032] In an embodiment of the present invention, the extending relief valve group includes an electric proportional relief valve arranged between the rodless chamber working oil circuit and the return oil circuit, the relief pressure of the electric proportional relief valve is related to the magnitude of the control current, and the controller is used to control the control current of the electric proportional relief valve according to the numerical value of the safety limit pressure; or

[0033] The extending relief valve group includes a first relief valve arranged between the rodless chamber working oil circuit and the return oil circuit. The first relief valve is a hydraulically controlled pilot relief valve. The extending relief valve group also includes an electric proportional relief valve arranged between the hydraulically controlled pilot oil circuit and the return oil circuit of the first relief valve. The relief pressure of the electric proportional relief valve is related to the control current. The controller is used to control the control current of the electric proportional relief valve according to the numerical value of the safety limit pressure.

[0034] To achieve the above-mentioned object, the present invention further provides a telescopic working equipment, wherein the telescopic working equipment includes the telescopic arm hydraulic control system described above.

[0035] Through the above technical solution, the telescopic arm extension control method provided by the embodiment of the present invention has the following beneficial effects:

[0036] As the telescopic boom is extended, the telescopic cylinder obtains real-time information about the boom's operating conditions and the piston rod's extension length to calculate the safety limit pressure for the cylinder's safe operation under the current operating conditions. After calculating the safety limit pressure, the relief pressure of the telescopic cylinder's extension relief valve group is set to that limit. This allows the system's pressure oil to overflow when the pressure reaches the safety limit, thus preventing damage to the telescopic cylinder due to overload and ensuring its safe operation.

[0037] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings are used to provide an understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0039] Figure 1 is a general step diagram of a telescopic arm extension control method according to an embodiment of the present invention;

[0040] Figure 2 is a diagram of further specific steps of step S200 according to an embodiment of the present invention;

[0041] Figure 3 is a diagram of one of the steps after step S300 according to an embodiment of the present invention;

[0042] Figure 4 is another step diagram after step S300 according to an embodiment of the present invention;

[0043] Figure 5 is a diagram of one of the steps after step S412 according to an embodiment of the present invention;

[0044] Figure 6 is another step diagram after step S412 according to an embodiment of the present invention;

[0045] Figure 7 2 is a schematic structural diagram of a first embodiment of a telescopic arm hydraulic control system according to an embodiment of the present invention;

[0046] Figure 8 2 is a schematic structural diagram of a second embodiment of a telescopic arm hydraulic control system according to an embodiment of the present invention;

[0047] Figure 9 2 is a schematic structural diagram of a third embodiment of a telescopic arm hydraulic control system according to an embodiment of the present invention;

[0048] Figure 10is a schematic structural diagram of a telescopic arm according to an embodiment of the present invention;

[0049] Figure 11 4 is a flow chart of extending the telescopic arm according to an embodiment of the present invention.

[0050] Description of Reference Numerals

[0051] 1. Telescopic cylinder; 11. Rodless chamber working oil circuit; 12. Rod chamber working oil circuit; 2. Reversing valve group; 3. Extending relief valve group; 31. Electric proportional relief valve; 32. First relief valve; 41. Retracting relief valve group; 42. Main relief valve; 43. Oil pump; 51. Telescopic arm; 52. Auxiliary arm. DETAILED DESCRIPTION

[0052] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0053] The telescopic arm extension control method of the present invention will be described below with reference to the accompanying drawings.

[0054] In order to increase the lifting range of the crane, some types of cranes will set the telescopic arm 51 to multiple sections, or as Figure 10 As shown, some cranes install a jib 52 on the boom during operation to increase the overall length of the telescopic arm 51. When the telescopic arm 51 is extended to a very long length, some arm sections may bend due to the weight of the telescopic arm 51, which inevitably causes the piston rod to bend.

[0055] Existing telescopic boom hydraulic systems have a fixed safety relief pressure for the cylinders. The working oil circuit will overflow only when the oil pressure in the cylinder reaches this pressure. The maximum thrust the piston rod can withstand varies depending on the degree of piston rod bending. In some cases, the hydraulic pressure in the telescopic boom system may not reach the safety relief pressure, but the cylinder has already reached its maximum thrust capacity. Continuing to operate the cylinder at this point can easily break the piston rod or strain the cylinder barrel, leading to more serious consequences.

[0056] In order to ensure the safe operation of the telescopic cylinder 1, the present invention provides a telescopic arm extension control method, wherein, Figure 1 and Figure 11 As shown, the telescopic arm extension control method includes:

[0057] S100: Collecting the working condition information of the telescopic arm 51 and the extension length information of the piston rod of the telescopic cylinder 1;

[0058] S200: Calculating a safety limit pressure of the telescopic cylinder 1 to ensure safe operation under the current working condition based on the working condition information and the extension length information of the piston rod;

[0059] S300: The relief pressure of the extension relief valve group 3 of the telescopic oil cylinder 1 is set according to the safety limit pressure.

[0060] The operating condition information of the telescopic boom 51 includes the total extended length of the telescopic boom 51, whether the telescopic boom 51 is equipped with a jib 52 or a tower arm, the extension status of each boom section of the telescopic boom 51 (fully extended or partially extended), and the pitch angle of the telescopic boom 51 when extended. Based on this operating condition information, the bending of the telescopic boom 51 can be calculated. Different degrees of bending of the telescopic boom 51 will result in different deflection forces on the piston rod when subjected to axial pressure, resulting in changes in the maximum thrust that the piston rod can withstand.

[0061] like Figure 7 and Figure 10 As shown, the extension of the telescopic arm 51 is generally achieved by the oil supply to the rodless chamber of the telescopic cylinder 1, and the telescopic relief valve group refers to the relief valve group of the rodless chamber of the telescopic cylinder 1 or the rodless chamber working oil circuit 11.

[0062] While extending the telescopic arm 51, the telescopic cylinder 1 calculates the safe operating pressure limit for the telescopic cylinder 1 under the current operating conditions by acquiring real-time information about the telescopic arm 51's operating condition and the piston rod's extension length. After calculating the safe operating pressure limit, the relief pressure of the telescopic cylinder 1's extension relief valve assembly 3 is set to the safe operating pressure limit. This allows the system pressure oil to overflow when the oil pressure reaches the safe operating pressure limit, thereby preventing damage to the telescopic cylinder 1 due to overload and ensuring its safe operation.

[0063] In an embodiment of the present invention, in order to more conveniently obtain the bending condition of the entire telescopic arm 51 , angle sensors may be further provided at the root and the head of the telescopic arm 51 .

[0064] In the embodiment of the present invention, the telescopic arm 51 is composed of a plurality of arm sections.

[0065] like Figure 2 and Figure 11 As shown, in an embodiment of the present invention, S200: calculating the safety limit pressure of the telescopic cylinder 1 to ensure safe operation under the current working condition based on the working condition information and the extension length information of the piston rod specifically includes:

[0066] S210: Calculating the force deflection vector of the telescopic cylinder 1 according to the working condition information;

[0067] S220: Calculating the theoretical maximum pressure that the telescopic cylinder 1 can withstand under the current working condition based on the force deflection vector and the extended length information of the piston rod of the telescopic cylinder 1;

[0068] S230: Select a pressure value between the theoretical maximum pressure and the actual working pressure of the telescopic oil cylinder 1 under the current working condition as a safety limit pressure.

[0069] During operation, the hydraulic control system for the telescopic boom is subject to the influence of external operations, and oil pressure fluctuations are inevitable. By selecting a pressure value between the theoretical maximum pressure and the actual operating pressure of telescopic cylinder 1 under the current operating conditions as the safety limit pressure, occasional oil pressure fluctuations can be avoided from causing overload of telescopic cylinder 1.

[0070] Among them, the method of calculating the theoretical maximum pressure that the telescopic cylinder 1 can withstand under the current working conditions based on the force deflection vector of the piston rod and the extension length of the piston rod is an existing technology and has been recorded in the engineering machinery design manual. Therefore, the present invention does not repeat the calculation process.

[0071] In an embodiment of the present invention, if the difference between the theoretical maximum pressure and the actual working pressure of the telescopic cylinder 1 under the current working conditions is large, the safety limit pressure value can be set to a median value between the theoretical maximum pressure and the actual working pressure, such as F3 = (F1 + F2) / 2, where F1 is the theoretical maximum pressure, F2 is the actual working pressure, and F3 is the safety limit pressure.

[0072] like Figure 11 As shown, in this embodiment of the present invention, the actual working pressure of the telescopic cylinder 1 under the current working conditions includes the current working pressure of the telescopic cylinder 1 and the working pressure of the telescopic cylinder 1 under the same working conditions recorded in historical data. By incorporating historical data, the rationality of the calculated safety limit pressure can be determined when the current working pressure of the telescopic cylinder 1 differs significantly from the working pressure of the telescopic cylinder 1 under the same working conditions recorded in historical data, thereby preventing occasional pressure fluctuations of the hydraulic oil from interfering with the calculated safety limit pressure. Furthermore, by incorporating historical data for comparison, abnormal working pressures in the telescopic cylinder 1 can be promptly detected and alerted, preventing the telescopic arm 51 from operating under unfavorable working conditions for extended periods of time.

[0073] like Figure 3 and Figure 11 As shown, in the embodiment of the present invention, S300: after setting the relief pressure of the extension relief valve group 3 of the telescopic oil cylinder 1 according to the safety limit pressure, the telescopic arm extension control method further includes:

[0074] S401: Confirm that the telescopic arm 51 is normally extended;

[0075] S402: During the normal extension of the telescopic arm 51, the relief pressure of the extension relief valve assembly 3 is adjusted in real time according to the change in the working condition of the telescopic arm 51 and the change in the extension length of the piston rod, until the telescopic arm 51 is extended to the full position.

[0076] During the extension of the telescopic arm 51, the maximum pressure that the telescopic cylinder 1 can withstand changes all the time. By calculating the matching safety limit pressure in real time according to the changes in the working condition information of the telescopic arm 51 and the changes in the extension length information of the piston rod, and adjusting the relief pressure of the extension relief valve group 3 in real time according to the recalculated safety limit pressure, the safety limit pressure can be automatically matched with the change of the state of the telescopic cylinder 1, thereby realizing full-cycle protection of the extension of the telescopic cylinder 1 and effectively preventing the occurrence of overload of the telescopic cylinder 1.

[0077] like Figure 4 and Figure 11 As shown, in the embodiment of the present invention, S300: after setting the relief pressure of the extension relief valve group 3 of the telescopic oil cylinder 1 according to the safety limit pressure, the telescopic arm extension control method further includes:

[0078] S411: Confirm that the telescopic arm 51 is not extended normally;

[0079] S412: Check whether the working condition information is entered correctly.

[0080] The operating condition of the telescopic arm 51 and the extension length of the piston rod of the telescopic cylinder 1 are typically monitored using a built-in sensor on the telescopic arm 51. Sometimes, due to vibrations from the operating machine, the sensor's detection may produce occasional errors. If the safety limit pressure is calculated based on erroneous detection results, the safety limit pressure may be too low, preventing the telescopic arm 51 from extending normally.

[0081] like Figure 5 and Figure 11 As shown, in an embodiment of the present invention, if the working condition information input is incorrect, the telescopic arm extension control method further includes:

[0082] S413: Correcting the working condition information;

[0083] S414: recalculating the safety limit pressure according to the corrected working condition information;

[0084] S415: Reset the relief pressure of the extension relief valve group 3 of the telescopic oil cylinder 1 according to the recalculated safety limit pressure.

[0085] Through the above operation, the self-checking and self-correcting functions of the machine can be realized when the telescopic arm 51 cannot be extended normally, thereby avoiding the occasional detection error of the sensing element from interfering with the extension operation of the telescopic arm 51.

[0086] like Figure 6 and Figure 11 As shown, in an embodiment of the present invention, if the working condition information is correctly input, the telescopic arm extension control method further includes:

[0087] S423: Check whether the telescopic arm 51 has other abnormal conditions;

[0088] S424: If yes, process the abnormal situation, recalculate the safety limit pressure and reset the relief pressure of the extending relief valve group 3; if no, increase the relief pressure of the extending relief valve group 3.

[0089] After a period of use, the telescopic arm 51 will inevitably experience slide wear, insufficient grease, and contact area sticking, resulting in the telescopic cylinder 1 being required to withstand higher operating pressures than before the sticking. If the telescopic arm 51 fails to extend normally, and the operating condition information is confirmed to be correctly entered, the telescopic arm 51 can be inspected for abnormalities such as slide wear, insufficient grease, and contact area sticking. If so, these factors will be taken into account when calculating the safe operating pressure. If not, to avoid safety hazards caused by emergency stops, the relief pressure of the extension relief valve assembly 3 will need to be forcibly increased to temporarily overload the telescopic cylinder 1.

[0090] The forced increase in the relief pressure of the extension relief valve assembly 3 can be automatically controlled by a built-in control program or manually controlled. When the telescopic cylinder 1 is in an overloaded working state for a short period of time, the alarm unit in the device can also be configured to issue an overload alarm for the telescopic cylinder 1.

[0091] To achieve the above purpose, Figure 7 、 Figure 8 and Figure 9 As shown, the present invention also provides a telescopic arm hydraulic control system, wherein the telescopic arm hydraulic control system includes:

[0092] Main oil circuit unit, including pressure oil circuit and return oil circuit;

[0093] The cylinder unit includes a telescopic cylinder 1 and a rod chamber working oil circuit 12 and a rodless chamber working oil circuit 11 of the telescopic cylinder 1. One end of the rod chamber working oil circuit 12 and the rodless chamber working oil circuit 11 are respectively connected to the rod chamber and the rodless chamber of the telescopic cylinder 1, and the other end is connected to the pressure oil circuit and the return oil circuit respectively through the reversing valve group 2;

[0094] The relief valve group 3 is extended and arranged between the rodless chamber working oil circuit 11 and the return oil circuit. The relief pressure of the relief valve group 3 can be electrically controlled and adjusted; and

[0095] The controller is electrically connected to the extension relief valve group 3 and is used to execute the telescopic arm extension control method described above.

[0096] As the telescopic cylinder 1 extends the telescopic arm 51, the sensing element monitors the operating condition of the telescopic arm 51 and the extension length of the piston rod of the telescopic cylinder 1 in real time. Upon receiving this information, the controller calculates the safety limit pressure required to ensure safe operation of the telescopic cylinder 1 under the current operating conditions. Based on this calculation, the controller sets the relief pressure of the extension relief valve assembly 3 of the telescopic cylinder 1 to the safety limit pressure. When the oil pressure in the rodless chamber working oil circuit 11 reaches the safety limit pressure, the extension relief valve assembly 3 releases the hydraulic oil, thereby preventing the telescopic cylinder 1 from being overloaded and ensuring its safe operation.

[0097] In the embodiment of the present invention, the pressure oil circuit is generally connected to the oil pumping port of the oil pump 43, and the return oil circuit is connected to the oil tank.

[0098] In the embodiment of the present invention, there are many arrangements for extending the relief valve group 3, such as Figure 7 As shown, the extended overflow valve group 3 can be an electric proportional overflow valve 31 arranged between the rodless chamber working oil circuit 11 and the return oil circuit. One end of the electric proportional overflow valve 31 is the electromagnetic control end, and the other end is the hydraulic control end. The overflow pressure of the electric proportional overflow valve 31 is related to the size of the control current of the electromagnetic control end (such as it can be positively correlated or negatively correlated). After calculating the safety limit pressure, the controller adjusts the control current of the electric proportional overflow valve 31 according to the numerical value of the safety limit pressure, thereby realizing the regulation of the overflow pressure of the electric proportional overflow valve 31.

[0099] like Figure 8 As shown, in an embodiment of the present invention, the extending relief valve group 3 can also be composed of a first relief valve 32 and an electric proportional relief valve 31. The first relief valve 32 is arranged between the rodless chamber working oil circuit 11 and the return oil circuit and the first relief valve 32 can be set as a hydraulically controlled pilot relief valve. The electric proportional relief valve 31 is arranged between the hydraulically controlled pilot oil circuit and the return oil circuit of the first relief valve 32. By controlling the relief pressure of the hydraulically controlled pilot oil circuit, the oil pressure of the hydraulically controlled pilot oil circuit of the hydraulically controlled pilot relief valve can be changed, thereby realizing the regulation of the relief pressure of the hydraulically controlled pilot relief valve.

[0100] In an embodiment of the present invention, the extending relief valve group 3 may also be composed of a first relief valve 32 and a manually adjustable proportional relief valve provided on a hydraulically controlled pilot oil circuit of the first relief valve 32 .

[0101] In this embodiment of the present invention, a main relief valve 42 can be provided on the pressure oil circuit to limit the maximum oil pressure of the entire telescopic boom hydraulic control system. A retraction relief valve assembly 41 can also be provided on the rodless chamber working oil circuit 11 to ensure safe operation of the telescopic boom hydraulic control system during retraction.

[0102] In the embodiment of the present invention, the oil pump 43 may be a variable displacement pump or a fixed displacement pump. When the oil pump 43 is a variable displacement pump, the electric proportional relief valve 31 may be directly disposed on the Ls oil path of the variable displacement pump.

[0103] like Figure 9 As shown, in the embodiment of the present invention, the electric proportional relief valve 31 and the electric proportional output valve can be integrated with the main reversing valve, the extension relief valve group 3, the main relief valve 42, and the retraction relief valve, or can be set separately.

[0104] To achieve the above objectives, the present invention further provides a telescopic working device, wherein the telescopic working device includes the telescopic arm hydraulic control system described above. Since the telescopic working device adopts all the technical solutions of the above embodiments, it at least has the beneficial effects brought about by the above embodiments, and the details will not be repeated here.

[0105] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0106] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0107] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0108] Although the embodiments of the present invention have been described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A telescopic arm extension control method, characterized in that: The telescopic arm extension control method includes: Collecting working condition information of the telescopic arm (51) and extension length information of the piston rod of the telescopic oil cylinder (1); Calculating a safety limit pressure of the telescopic oil cylinder (1) to ensure safe operation under the current working condition based on the working condition information and the extension length information of the piston rod; Setting the relief pressure of the extension relief valve group (3) of the telescopic oil cylinder (1) according to the safety limit pressure; Calculating the safety limit pressure of the telescopic oil cylinder (1) to ensure safe operation under the current working condition based on the working condition information and the extension length information of the piston rod of the telescopic oil cylinder (1) specifically includes: Calculating the force deflection vector of the piston rod of the telescopic oil cylinder (1) according to the working condition information; Calculating the theoretical maximum pressure that the telescopic oil cylinder (1) can withstand under the current working condition based on the force deflection vector of the piston rod and the extension length information of the piston rod; A pressure value between the theoretical maximum pressure and the actual working pressure of the telescopic oil cylinder (1) under the current working condition is selected as the safety limit pressure.

2. The telescopic arm extension control method according to claim 1, characterized in that: The actual working pressure of the telescopic oil cylinder (1) under the current working condition includes the working pressure of the telescopic oil cylinder (1) at the current moment and the working pressure of the telescopic oil cylinder (1) under the same working condition recorded in historical data.

3. The telescopic arm extension control method according to claim 1, characterized in that: After the relief pressure of the extension relief valve group (3) of the telescopic oil cylinder (1) is set according to the safety limit pressure, the telescopic arm extension control method further comprises: Confirming that the telescopic arm (51) is extended normally; During the normal extension of the telescopic arm (51), the overflow pressure of the extension overflow valve group (3) is adjusted in real time according to the change of the working condition of the telescopic arm (51) and the change of the extension length of the piston rod until the telescopic arm (51) is extended into place.

4. The telescopic arm extension control method according to claim 1, characterized in that: After the relief pressure of the extension relief valve group (3) of the telescopic oil cylinder (1) is set according to the safety limit pressure, the telescopic arm extension control method further comprises: Confirm that the telescopic arm (51) is not extended normally; Check whether the working condition information is entered correctly.

5. The telescopic arm extension control method according to claim 4, characterized in that: If the input working condition information is incorrect, the telescopic arm extension control method further includes: Correcting the operating condition information; recalculating the safety limit pressure according to the corrected working condition information; The overflow pressure of the extension overflow valve group (3) of the telescopic oil cylinder (1) is reset according to the recalculated safety limit pressure.

6. The telescopic arm extension control method according to claim 4, characterized in that: If the input working condition information is correct, the telescopic arm extension control method further includes: Check whether the telescopic arm (51) has other abnormal conditions; If it exists, the abnormal situation is processed, the safety limit pressure is recalculated, and the overflow pressure of the extending overflow valve group (3) is reset; if it does not exist, the overflow pressure of the extending overflow valve group (3) is increased.

7. A telescopic arm hydraulic control system, characterized in that: The telescopic arm hydraulic control system includes: Main oil circuit unit, including pressure oil circuit and return oil circuit; The oil cylinder unit comprises a telescopic oil cylinder (1) and a rod chamber working oil circuit (12) and a rodless chamber working oil circuit (11) of the telescopic oil cylinder (1), wherein the rod chamber working oil circuit (12) and the rodless chamber working oil circuit (11) are respectively connected to the pressure oil circuit and the return oil circuit via a reversing valve group (2); An extension relief valve group (3) is arranged between the rodless chamber working oil circuit (11) and the return oil circuit, and the relief pressure of the extension relief valve group (3) can be electrically controlled and adjusted; and A controller is electrically connected to the extension relief valve group (3) and is used to execute the telescopic arm extension control method according to any one of claims 1 to 6.

8. The telescopic arm hydraulic control system according to claim 7, characterized in that: The extending relief valve group (3) includes an electric proportional relief valve (31) provided between the rodless chamber working oil circuit (11) and the return oil circuit, the relief pressure of the electric proportional relief valve (31) is related to the magnitude of the control current, and the controller is used to control the control current of the electric proportional relief valve (31) according to the numerical value of the safety limit pressure; or The extending relief valve group (3) includes a first relief valve (32) arranged between the rodless chamber working oil circuit (11) and the return oil circuit, and the first relief valve (32) is a hydraulically controlled pilot relief valve. The extending relief valve group (3) also includes an electric proportional relief valve (31) arranged between the hydraulically controlled pilot oil circuit of the first relief valve (32) and the return oil circuit, and the relief pressure of the electric proportional relief valve (31) is related to the magnitude of the control current. The controller is used to control the control current of the electric proportional relief valve (31) according to the numerical value of the safety limit pressure.

9. A telescopic working device, characterized in that: It comprises the telescopic arm hydraulic control system according to any one of claims 7 to 8.

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