Extension control method of telescopic arm, hydraulic control system of telescopic arm and telescopic operation equipment

Abstract

The 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 comprises the steps that working condition information of a telescopic arm and extension length information of a piston rod of a telescopic oil cylinder are collected; according to the working condition information and the extension length information of the piston rod, safe limited pressure for ensuring safe work of the telescopic oil cylinder under the current working condition is calculated; and the overflow pressure of the telescopic oil cylinder extending out of the overflow valve bank is set according to the safe limited pressure. The overflow pressure of the extension overflow valve group of the telescopic oil cylinder is set as the safety limit pressure, and the system pressure oil can overflow when the oil pressure of the system pressure oil reaches the safety limit pressure, so that the oil cylinder damage caused by overload work of the telescopic oil cylinder is avoided, and the safety operation of the telescopic oil cylinder is ensured.

Description

Technical Field

[0001] The 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] At present, there are two main ways to extend the multi-section telescopic arm of a crane: one is the multi-stage telescopic cylinder plus rope row technology, and the other is the single-cylinder latch telescopic technology. Both methods involve telescopic cylinders. The cylinder barrel and piston rod of the telescopic cylinder in the multi-stage telescopic cylinder plus rope row structure are fixed on different arm sections respectively. 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 with the previous level, the target arm and other arm sections inside can be extended together. After reaching the preset position, the arm pin is released to fix the target arm with the previous arm section, and then the piston rod (cylinder) is controlled to retract alone, and the piston rod (cylinder) is connected to the latch mechanism of the arm section of the previous level. Repeat the above steps to achieve the extension of the telescopic arm in sequence.

[0003] The working overflow pressure of the existing telescopic oil cylinder is a fixed value, and the maximum thrust that the oil cylinder can withstand will also change according to the extension posture, amplitude change angle, and load of the telescopic arm. Sometimes the working oil pressure of the oil cylinder has not reached the overflow pressure, and the telescopic oil cylinder has reached the thrust limit that it can withstand. At this time, if the overflow valve is set according to the fixed working overflow pressure, the oil cylinder is easy to overload and cause damage to the oil cylinder. Summary of the invention

[0004] In view of 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 the safety limit pressure of the telescopic cylinder to ensure safe operation under the current working condition according to 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 according to 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 according to the force deflection vector and the extension 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 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 cylinder under the current working condition includes the working pressure of the telescopic cylinder at the current moment and the working pressure of the telescopic cylinder under the same working condition recorded in the historical data.

[0014] In an embodiment of the present invention, S300: after 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, S300: after 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 operating condition information is input 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 working condition information is correctly input, the telescopic arm extension control method further includes:

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

[0026] S424: If it exists, the abnormal situation is processed, and the safety limit pressure is recalculated and the relief pressure of the extended relief valve group is reset. If it does not exist, the relief pressure of the extended relief valve group is increased.

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

[0028] The main oil circuit unit includes a pressure oil circuit and an oil return 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, wherein 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 extending relief valve group is arranged between the rodless chamber working oil circuit and the return oil circuit, and the relief pressure of the extending 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 extension 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 overflow valve group includes a first overflow valve arranged between the rodless chamber working oil circuit and the return oil circuit. The first overflow valve is a hydraulically controlled pilot overflow valve. The extending overflow valve group also includes an electric proportional overflow valve arranged between the hydraulically controlled pilot oil circuit and the return oil circuit of the first overflow valve. The overflow pressure of the electric proportional overflow valve is related to the control current. The controller is used to control the control current of the electric proportional overflow valve according to the numerical value of the safety limit pressure.

[0034] To achieve the above object, the present invention further provides a telescopic working equipment, wherein the telescopic working equipment comprises 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] When the telescopic cylinder pushes the telescopic arm to extend, the telescopic cylinder can calculate the safety limit pressure of the telescopic cylinder to ensure safe operation under the current working condition by obtaining the working condition information of the telescopic arm and the extension length information of the piston rod in real time. After calculating the safety limit pressure, by setting the relief pressure of the extension relief valve group of the telescopic cylinder to the safety limit pressure, the system pressure oil can be overflowed when the oil pressure of the system pressure oil reaches the safety limit pressure, thereby avoiding damage to the cylinder caused by overloading of the telescopic cylinder and ensuring the safe operation of the telescopic cylinder.

[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 specific embodiments, 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 further specific step diagram of step S200 according to an embodiment of the present invention;

[0041] Figure 3 is a step diagram 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 step diagram 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 is a structural schematic diagram of a first implementation of a telescopic arm hydraulic control system according to an embodiment of the present invention;

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

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

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

[0049] Fig.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 in conjunction with 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 used 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 may have the telescopic arm 51 set to multiple sections, or Fig.10 As shown, some cranes will 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 will bend due to the weight of the telescopic arm 51, resulting in inevitable bending of the piston rod.

[0055] The safety overflow pressure of the oil cylinder in the existing telescopic arm hydraulic system is a fixed value. Only when the oil pressure in the oil cylinder reaches the safety overflow pressure, the working oil circuit of the oil cylinder will overflow. The maximum thrust that the piston rod can withstand will also be different depending on the degree of bending of the piston rod. In some cases, sometimes the oil pressure of the telescopic arm hydraulic system has not reached the safety overflow pressure, and the oil cylinder has reached the maximum thrust that it can withstand. At this time, if the oil cylinder continues to work, it is easy to cause the piston rod to break or the cylinder to be strained, 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 Fig.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 the safety limit pressure of the telescopic cylinder 1 to ensure safe operation under the current working condition according to the working condition information and the extension length information of the piston rod;

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

[0060] The working condition information of the telescopic arm 51 includes the total extension length of the telescopic arm 51, whether the telescopic arm 51 is equipped with a jib 52 or a tower arm, the extension condition of each arm section of the telescopic arm 51 (full extension or partial extension), the pitch angle of the telescopic arm 51 when extended, etc. The bending condition of the telescopic arm 51 can be calculated based on the working condition information. The deflection force on the piston rod when it is subjected to axial pressure will be different when the bending degree of the telescopic arm 51 is different, resulting in a change in the maximum thrust that the piston rod can withstand.

[0061] like Figure 7 and Fig.10 As shown, the extension of the telescopic arm 51 is generally achieved by the oil inlet into 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] In the process of pushing the telescopic arm 51 to extend, the telescopic cylinder 1 can calculate the safety limit pressure of the telescopic cylinder 1 to ensure safe operation under the current working condition by acquiring the working condition information of the telescopic arm 51 and the extension length information of the piston rod in real time. After calculating the safety limit pressure, by setting the relief pressure of the extension relief valve group 3 of the telescopic cylinder 1 to the safety limit pressure, the system pressure oil can be overflowed when the oil pressure of the system pressure oil reaches the safety limit pressure, thereby avoiding overloading of the telescopic cylinder 1 and causing damage to the cylinder, and ensuring the safe operation of the telescopic cylinder 1.

[0063] In the embodiment of the present invention, in order to more conveniently obtain the bending condition of the entire telescopic arm 51 , angle sensors may be respectively 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 Fig.11 As shown, in the 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 according to 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 according to the force deflection vector and the extension 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 cylinder 1 under the current working condition as a safety limit pressure.

[0069] During the operation of the telescopic arm hydraulic control system, the oil pressure will inevitably fluctuate due to the influence of external operations. By selecting a pressure value between the theoretical maximum pressure and the actual working pressure of the telescopic cylinder 1 under the current working conditions as the safety limit pressure, occasional oil pressure fluctuations can be avoided to cause overload of the 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 condition based on the force deflection vector of the piston rod and the extension length of the piston rod is a prior art 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 value of the safety limit pressure can be set to a median value between the theoretical maximum pressure and the actual working pressure, such as F3 = (F1 + F2) / 2, F1 is the theoretical maximum pressure, F2 is the actual working pressure, and F3 is the safety limit pressure.

[0072] like Fig.11 As shown, in the embodiment of the present invention, 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 the historical data. By introducing the historical data, when the working pressure of the telescopic oil cylinder 1 at the current moment differs too much from the working pressure of the telescopic oil cylinder 1 under the same working condition recorded in the historical data, the rationality of the calculation result of the safety limit pressure can be judged, thereby avoiding the occasional pressure fluctuation of the hydraulic oil from interfering with the calculation result of the safety limit pressure. At the same time, by introducing the historical data for comparison, when the working pressure of the telescopic oil cylinder 1 is abnormal, the abnormality can be discovered in time and a warning can be given, thereby avoiding the telescopic arm 51 from working under bad working conditions for a long time.

[0073] like Figure 3 and Fig.11 As shown, in the embodiment of the present invention, S300: 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 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 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 to the right position.

[0076] During the extension of the telescopic arm 51, the maximum pressure that the telescopic cylinder 1 can withstand changes all the time. The matching safety limit pressure is calculated in real time according to the changes in the working condition information of the telescopic arm 51 and the extension length information of the piston rod, and the relief pressure of the extension relief valve group 3 is adjusted 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 for the extension of the telescopic cylinder 1 and effectively preventing the occurrence of overload of the telescopic cylinder 1.

[0077] like Figure 4 and Fig.11 As shown, in the embodiment of the present invention, S300: 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 includes:

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

[0079] S412: Check whether the operating condition information is input correctly.

[0080] The working condition of the telescopic arm 51 and the extension length of the piston rod of the telescopic oil cylinder 1 are generally detected by the induction element on the telescopic arm 51. Sometimes, due to the vibration of the working machine body, the detection of the induction element will produce occasional errors. If the safety limit pressure is calculated based on the wrong detection result, the value of the safety limit pressure may be too small, and the telescopic arm 51 cannot be extended normally.

[0081] like Figure 5 and Fig.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 normally extended, thereby avoiding the interference of occasional detection errors of the sensing element on the extension operation of the telescopic arm 51.

[0086] like Figure 6 and Fig.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 it exists, the abnormal situation is processed, and the safety limit pressure is recalculated and the relief pressure of the extending relief valve group 3 is reset. If it does not exist, the relief pressure of the extending relief valve group 3 is increased.

[0089] After the telescopic arm 51 has been used for a period of time, it is inevitable that the slider will be worn, the grease is insufficient, the contact part is stuck, etc., resulting in the telescopic oil cylinder 1 in the same working condition to withstand a higher working pressure than before the sticking. When the telescopic arm 51 cannot be extended normally, if it is confirmed that the working condition information is correctly input, it is possible to first check whether the telescopic arm 51 has abnormal conditions such as slider wear, insufficient grease, and contact part sticking. If so, the factors such as slider wear and insufficient grease are taken into consideration when calculating the safe working pressure. If not, in order to avoid safety hazards caused by emergency stops, it is necessary to forcibly increase the overflow pressure of the extension overflow valve group 3 so that the telescopic oil cylinder 1 is in an overloaded working state for a short time.

[0090] The forced increase of the relief pressure of the relief valve group 3 can be performed by automatic control of the built-in control program or by manual control. When the telescopic cylinder 1 is in an overloaded working state for a short time, the alarm unit in the device can also be configured to alarm the overload of the telescopic cylinder 1.

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

[0092] The main oil circuit unit includes a pressure oil circuit and an oil return circuit;

[0093] 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. 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 oil cylinder 1, and the other end is respectively connected to the pressure oil circuit and the return oil circuit through the reversing valve group 2;

[0094] The extending overflow valve group 3 is arranged between the rodless chamber working oil circuit 11 and the return oil circuit, and the overflow pressure of the extending overflow 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] When the telescopic cylinder 1 pushes the telescopic arm 51 to extend, the sensing element will monitor the working condition information of the telescopic arm 51 and the extension length information of the piston rod of the telescopic cylinder 1 in real time. After receiving the working condition information of the telescopic arm 51 and the extension length information of the piston rod detected by the sensing element, the controller will calculate the safety limit pressure of the telescopic cylinder 1 to ensure safe operation under the current working condition, and set the relief pressure of the extension relief valve group 3 of the telescopic cylinder 1 to the safety limit pressure according to the calculation result. When the oil pressure of the rodless chamber working oil circuit 11 reaches the safety limit pressure, the extension relief valve group 3 will overflow the hydraulic oil, thereby avoiding the telescopic cylinder 1 from being in an overloaded working state and ensuring the safe operation of the telescopic cylinder 1.

[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 oil return 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 extension 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 adjustment of the relief pressure of the hydraulically controlled pilot relief valve.

[0100] In the 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 arranged on the hydraulically controlled pilot oil circuit of the first relief valve 32 .

[0101] In the embodiment of the present invention, a main overflow valve 42 may be provided on the pressure oil circuit to limit the maximum oil pressure of the entire telescopic arm hydraulic control system. A retraction overflow valve group 41 may also be provided on the rodless chamber working oil circuit 11 to ensure safe operation of the telescopic arm hydraulic control system when retracting.

[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 Fig. 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 arranged separately.

[0104] To achieve the above object, 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 has at least the beneficial effects brought by the above embodiments, which 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 as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0106] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0107] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0108] Although the embodiments of the present invention have been described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary 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 comprises: 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; The overflow pressure of the extension overflow valve group (3) of the telescopic oil cylinder (1) is set according to the safety limit pressure.

2. The telescopic arm extension control method according to claim 1, characterized in that: 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 according to 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 cylinder (1) under the current working condition is selected as the safety limit pressure.

3. The telescopic arm extension control method according to claim 2, characterized in that: The actual working pressure of the telescopic oil cylinder (1) under the current working condition comprises 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 the historical data.

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: Confirming that the telescopic arm (51) is extended normally; During the normal extension of the telescopic arm (51), the relief pressure of the extension relief valve group (3) is adjusted in real time according to changes in the working condition of the telescopic arm (51) and changes in the extension length of the piston rod until the telescopic arm (51) is extended into place.

5. 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 not extended normally; Check whether the operating condition information is entered incorrectly.

6. The telescopic arm extension control method according to claim 5, characterized in that: If the working condition information is incorrectly input, the telescopic arm extension control method further includes: Correcting the operating condition information; recalculating the safety limit pressure according to the corrected operating 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.

7. The telescopic arm extension control method according to claim 5, characterized in that: If the working condition information is correctly input, 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 extension overflow valve group (3) is reset; if it does not exist, the overflow pressure of the extension overflow valve group (3) is increased.

8. A telescopic arm hydraulic control system, characterized in that: The telescopic arm hydraulic control system comprises: The main oil circuit unit includes a pressure oil circuit and an oil return 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 oil return 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 7.

9. The telescopic arm hydraulic control system according to claim 8, characterized in that: The extension relief valve group (3) comprises an electric proportional relief valve (31) arranged 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.

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

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