Floating oil cylinder hydraulic system and aerial work machine

Abstract

The utility model belongs to the field of aerial work machines, and relates to a floating oil cylinder hydraulic system and an aerial work machine. The floating oil cylinder hydraulic system comprises a left front axle oil cylinder and a left front reversing valve used for switching and controlling the left front axle oil cylinder to stretch out and draw back. The right front axle oil cylinder comprises a right front reversing valve used for switching and controlling the right front axle oil cylinder to stretch out and draw back; a left front short-circuit oil way is connected between a rod cavity and a rodless cavity of the left front axle oil cylinder, the left front control valve set comprises a left front on-off valve used for controlling the left front short-circuit oil way in an on-off mode, and a right front short-circuit oil way is connected between a rod cavity and a rodless cavity of the right front axle oil cylinder. The right front control valve set comprises a right front on-off valve used for controlling on-off of the right front short circuit oil way. The left front axle oil cylinder and the right front axle oil cylinder are double-acting oil cylinders, so that the problems of hydraulic oil leakage risk and exhaust difficulty of a single-acting oil cylinder can be solved. Floating or locking of the oil cylinder can be achieved by controlling connection and disconnection of the short-circuit oil way. The leveling function can be achieved by controlling the left front reversing valve and the right front reversing valve.

Description

Technical Field

[0001] The present application belongs to the field of aerial work machinery, and in particular, relates to a floating cylinder hydraulic system and an aerial work machinery. Background Art

[0002] The chassis of aerial work machinery generally needs to take into account both mobile and fixed machinery, and the floating cylinder is a key factor. When moving the machinery, the floating cylinder needs to be unlocked, that is, the cylinder is in a floating state, so that the machinery can pass through potholes and roads smoothly. When lifting the boom, the floating cylinder needs to be locked, that is, the chassis is fixed by the cylinder to improve the safety level of aerial work. In the prior art, the safety and performance control of the floating cylinder of the chassis of aerial work machinery have more or less defects, and it is difficult to take both into account. Summary of the invention

[0003] The purpose of the present application is to provide a floating cylinder hydraulic system and an aerial work machine to improve the safety, reliability and working performance of the aerial work machine.

[0004] To achieve the above objectives, the present application provides a floating cylinder hydraulic system, comprising:

[0005] A left front axle oil cylinder, wherein the left front control valve group of the left front axle oil cylinder comprises a left front reversing valve for switching and controlling the extension and retraction of the left front axle oil cylinder; and

[0006] A right front axle oil cylinder, wherein the right front control valve group of the right front axle oil cylinder comprises a right front reversing valve for switching and controlling the extension and retraction of the right front axle oil cylinder;

[0007] Among them, a left front short-circuit oil circuit is connected between the rod chamber and the rodless chamber of the left front axle cylinder, and the left front control valve group includes a left front on-off valve for on-off control of the left front short-circuit oil circuit; a right front short-circuit oil circuit is connected between the rod chamber and the rodless chamber of the right front axle cylinder, and the right front control valve group includes a right front on-off valve for on-off control of the right front short-circuit oil circuit.

[0008] In some embodiments, the left front short-circuit oil circuit includes:

[0009] A left front rodless chamber bypass oil circuit extends from a left front rodless chamber working oil circuit bypass branch of the left front axle oil cylinder and is provided with a left front rodless chamber on-off valve;

[0010] A left front rod chamber side connection oil circuit extends from a side branch of the left front rod chamber working oil circuit of the left front axle oil cylinder and is provided with a left front rod chamber on-off valve;

[0011] Wherein, the left front on-off valve includes the left front rodless chamber on-off valve and the left front rod chamber on-off valve.

[0012] In some embodiments, the right front short-circuit oil circuit includes:

[0013] A right front rodless chamber bypass oil circuit extends from a right front rodless chamber working oil circuit bypass branch of the right front axle oil cylinder and is provided with a right front rodless chamber on-off valve;

[0014] A right front rod chamber bypass oil circuit extends from a right front rod chamber working oil circuit bypass branch of the right front axle oil cylinder and is provided with a right front rod chamber on-off valve;

[0015] Wherein, the right front on-off valve includes the right front rodless chamber on-off valve and the right front rod chamber on-off valve.

[0016] In some embodiments, the left front rodless chamber on-off valve, the left front rod chamber on-off valve, the right front rodless chamber on-off valve and the right front rod chamber on-off valve are all two-position two-way solenoid valves and include a hydraulic locking position and a conduction position. In the hydraulic locking position, hydraulic oil can flow from one side of the solenoid valve to the rodless chamber and be blocked in the reverse direction. In the conduction position, the oil ports on both sides of the solenoid valve are connected.

[0017] In some embodiments, the left front short-circuit oil circuit and the right front short-circuit oil circuit are both hydraulically connected to an oil return circuit.

[0018] In some embodiments, an adjustable overflow valve and / or back pressure valve is provided in the oil return circuit.

[0019] In some embodiments, the floating cylinder hydraulic system includes:

[0020] A hydraulic pump is used to pump hydraulic oil and deliver it in parallel to the oil inlets of the left front reversing valve and the right front reversing valve.

[0021] In some embodiments, the floating cylinder hydraulic system includes a controller configured to:

[0022] Controlling and starting the hydraulic pump;

[0023] The left front reversing valve and the right front reversing valve are switched and controlled respectively, so that the piston of the left front axle oil cylinder and the piston of the right front axle oil cylinder respectively perform a number of full stroke movements;

[0024] The left front on-off valve and the right front on-off valve are controlled so that the left front short-circuit oil circuit and the right front short-circuit oil circuit are both kept in a conducting state.

[0025] In some embodiments, the left front reversing valve and the right front reversing valve are switched and controlled respectively, so that the piston of the left front axle oil cylinder and the piston of the right front axle oil cylinder respectively perform a number of full stroke movements, further comprising:

[0026] The left front on-off valve and the right front on-off valve are controlled so that the left front short-circuit oil circuit and the right front short-circuit oil circuit remain cut off.

[0027] In addition, the present application also provides an aerial work machinery, including the floating cylinder hydraulic system mentioned above in the present application, the left front axle cylinder and the right front axle cylinder are installed as floating cylinders at both ends of the front axle of the aerial work machinery, and the aerial work machinery also includes a left rear axle cylinder and a right rear axle cylinder fixed at both ends of the rear axle.

[0028] In the floating cylinder hydraulic system of the present application, both the left front axle cylinder and the right front axle cylinder use double-acting cylinders, and both the rod chamber and the rodless chamber of the cylinder can independently supply and return oil, thereby solving the risk of hydraulic oil leakage and exhaust difficulties of single-acting cylinders. The left front axle cylinder's rod chamber and the rodless chamber are connected with a left front short-circuit oil circuit and its left front on-off valve, and the right front axle cylinder's rod chamber and the rodless chamber are connected with a right front short-circuit oil circuit and its right front on-off valve, thereby controlling the on-off of the short-circuit oil circuit to achieve floating or locking of the cylinder. By switching and controlling the left front reversing valve and the right front reversing valve, the leveling of the left and right front axle cylinders can also be controlled independently, which improves the safety and reliability of the aerial work machinery while also improving the working performance of the machinery.

[0029] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without creative work. In the drawings:

[0031] Figure 1 A hydraulic principle diagram of a hydraulic control system of an aerial work machine in the prior art;

[0032] Figure 2 A hydraulic principle diagram of a floating cylinder hydraulic system of an aerial work machine according to a specific embodiment of the present application; and

[0033] Figure 3 , Figure 4 They are respectively hydraulic principle diagrams of a floating cylinder hydraulic system according to another specific embodiment of the present application.

[0034] Description of Reference Numerals

[0035] 1 First floating cylinder 2 Second floating cylinder

[0036] 3 Telescopic control reversing valve 4 First locking reversing valve

[0037] 5 Second locking reversing valve 6 Pressure reducing valve

[0038] 7 First check valve 8 Second check valve

[0039] 9 Third one-way valve 10 Damping

[0040] 11 The third oil cylinder 12 The fourth oil cylinder

[0041] 13 The third reversing valve 14 The fourth reversing valve

[0042] 15 Relief valve 16 Hydraulic pump

[0043] 20 Left front axle cylinder 21 Left front reversing valve

[0044] 22 Left front balancing valve group 23 Left front rodless chamber on-off valve

[0045] 24 Left front rod chamber on-off valve 25 Right front axle cylinder

[0046] 26 Right front reversing valve 27 Right front balancing valve group

[0047] 28 Right front rodless chamber on-off valve 29 Right front rod chamber on-off valve

[0048] L Rodless chamber main oil circuit P Pressure oil circuit

[0049] L1 First rodless chamber oil circuit L2 Second rodless chamber oil circuit DETAILED DESCRIPTION

[0050] The specific implementation of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present application, and is not used to limit the present application.

[0051] The floating cylinder hydraulic system and aerial work machinery according to the present application will be described below with reference to the accompanying drawings.

[0052] Aerial work machinery is a machine that relies on the chassis to move. It usually moves with four tires when walking. When encountering potholes, if all four tires are fixed on the chassis, the walking state will be abnormally bumpy. In order to improve this state, the front two tires are specially installed on the front axle, and the front axle is fixed with a floating cylinder. In this way, the front two tires are floating when walking, so that the chassis will try to ensure horizontal movement when walking. However, when the aerial work machinery lifts the boom, the chassis needs to be fixed to ensure lifting safety.

[0053] The inventors of the present application have summarized and found in a large number of work practices that the floating cylinders of existing aerial work machinery mostly use single-acting floating cylinders, and their control relies on a single balance valve to lock the floating cylinder. When floating, it relies on opening the pilot oil circuit of the single balance valve so that the rodless chamber working oil circuit of the floating cylinder is connected with the rod chamber working oil circuit. When the motor drives the gear pump to supply oil, the floating cylinder is replenished with oil by the one-way valve of the single balance valve by default. Since this type of cylinder is a single-acting cylinder, it is difficult to discharge the air inside the floating cylinder. If there is air in the floating cylinder, the floating cylinder cannot be effectively locked, and there is even a risk of tipping over of the aerial work machinery. In addition, since there is no hydraulic oil entering the rod chamber of the single-acting cylinder, there is a high risk of hydraulic oil leakage in the rod chamber after long-term use. In addition, since the left and right floating cylinders are installed on the integral front axle, only the left and right floating cylinders can be controlled at the same time. In the case where the front axle is separated at both ends, it is difficult to control the left and right floating cylinders at the same time, that is, it is impossible to control the left and right floating cylinders through the common pilot oil circuit of the left and right floating balance valves (see Figure 1 ) to simultaneously control the floating function of the left and right cylinders. If you need to adjust the horizontal state of the chassis, you need to control the left and right floating cylinders separately. Figure 1 The hydraulic system in the vehicle obviously cannot realize the separate control of the left and right floating cylinders.

[0054] Specifically, the present application discloses a novel floating cylinder hydraulic system, which is applied to aerial work machinery. Figure 2 As shown, in a specific embodiment, the floating cylinder hydraulic system includes:

[0055] A first floating cylinder 1 and a second floating cylinder 2;

[0056] The telescopic control reversing valve 3 is used to selectively supply the pressure oil of the pressure oil circuit P to the rod chamber of the first floating cylinder 1 or the second floating cylinder 2;

[0057] A first locking reversing valve 4 is provided in a first rodless chamber oil passage L1 connecting the rodless chamber of the first floating oil cylinder 1 and the pressure oil passage P; and

[0058] The second locking reversing valve 5 is arranged in the second rodless chamber oil circuit L2 connecting the rodless chamber of the second floating oil cylinder 2 and the pressure oil circuit P;

[0059] A floating connecting oil circuit is connected between the first locking reversing valve 4 and the second locking reversing valve 5 .

[0060] The present application particularly adopts a double-acting floating oil cylinder. Compared with a single-acting floating oil cylinder, the rod chamber can be independently supplied with oil, so that not only can the air be excluded and the reliable locking and floating functions can be realized, but also the active control of the extension and contraction of the oil cylinder can be realized. For example, when it is necessary to cross an obstacle, the chassis can also be actively leveled. For this purpose, a rod chamber oil circuit and its extension and contraction control reversing valve 3 are introduced to realize the independent supply of oil to the rod chamber of the oil cylinder. Further, combined with the introduction of the first locking reversing valve 4 and the second locking reversing valve 5, the hydraulic connection and disconnection between the rodless chamber of the first floating oil cylinder 1 and the pressure oil circuit P, and the hydraulic connection and disconnection between the rodless chamber of the second floating oil cylinder 2 and the pressure oil circuit P can be reliably controlled, so that the active extension and contraction control of the floating oil cylinder can be realized. Through the floating connection oil circuit connected between the first locking reversing valve 4 and the second locking reversing valve 5, the rodless chambers of the two floating oil cylinders can be connected to realize the floating control and effect of the floating oil cylinder.

[0061] Comparatively, if Figure 1 As shown, in the existing floating cylinder hydraulic control system of aerial work machinery, the hydraulic oil in the oil tank passes through the filter to the gear pump driven by the motor. After the hydraulic oil is pumped through the one-way valve and the pressure reducing valve, one of the hydraulic oil is directly connected to the one-way valve in the two single balance valves, and then enters the rodless chambers of the left and right front axle floating cylinders respectively, and the other hydraulic oil is delivered to the reversing valve. When the electromagnet Y01 is energized, by controlling the reversing of the electromagnetic reversing valve, the hydraulic oil can enter the pilot oil circuit of the single balance valve to open the single balance valve, so that the rodless chambers of the left and right front axle cylinders are connected to each other, and the left and right front axle cylinders realize the floating function. When the electromagnet Y01 is not energized, the left and right front axle cylinders realize the locking function.

[0062] Among them, since the left and right front axle cylinders are single-acting cylinders, no hydraulic oil enters the rod chamber. It is difficult to expel air from the rodless chamber of the hydraulic cylinder, and the aerial work machinery needs to repeatedly drive over the faulty object, and the floating cylinder needs to move up and down to expel the air. When there is residual air in the rodless chamber of the floating cylinder, the locking function of the floating cylinder may not work. If an exhaust joint is added, the exhaust joint will also increase the risk of hydraulic oil leakage. Since no hydraulic oil enters the rod chamber of the single-acting cylinder, the risk of hydraulic oil leakage in the rod chamber is high after long-term use. It can be seen that compared with the present application, Figure 1 The single-acting floating cylinder can only realize the functions of locking and floating, but cannot realize Figure 2 The active control of the telescopic function of the floating cylinder makes it difficult to achieve the crossing function when the aerial work machinery encounters an obstacle and needs to cross it. When the aerial work machinery needs to actively adjust the parallelism of the chassis, it is also difficult to achieve.

[0063] In order to realize the floating function or the lifting of the oil cylinder, it is necessary to supply oil to the rodless chamber of the oil cylinder and realize effective and reliable hydraulic locking. For this purpose, the floating oil cylinder hydraulic system may also include:

[0064] The rodless chamber main oil circuit L has one end connected to the pressure oil circuit P and the other end branched to the first rodless chamber oil circuit L1 and the second rodless chamber oil circuit L2;

[0065] Among them, the first rodless chamber oil circuit L1 is provided with a first one-way valve 7 connected in series with the first locking reversing valve 4, the second rodless chamber oil circuit L2 is provided with a second one-way valve 8 connected in series with the second locking reversing valve 5, and the rodless chamber total oil circuit L is provided with a third one-way valve 9. The first one-way valve 7, the second one-way valve 8 and the third one-way valve 9 are arranged closely and are all configured to allow pressure oil to flow from the pressure oil circuit P to the rodless chamber and to cut off the reverse flow.

[0066] like Figure 2 As shown, the one-way valve group includes three, for the rodless chamber of the first floating oil cylinder 1, the first one-way valve 7 and the third one-way valve 9 form a two-stage hydraulic lock, and for the rodless chamber of the second floating oil cylinder 2, the second one-way valve 8 and the third one-way valve 9 form a two-stage hydraulic lock. This redundant hydraulic locking design can more effectively prevent oil leakage from the rodless chamber, especially when the oil impurities cause the valve ports of individual one-way valves to open under long-term pressurization.

[0067] When supplying oil to the rodless chamber of the oil cylinder, the pressure oil in the pressure oil circuit P needs to overcome the back pressure of the third check valve 9 in the rodless chamber total oil circuit L, and then one way passes through the first rodless chamber oil circuit L1, and then overcomes the back pressure of the first check valve 7 to flow to the rodless chamber of the first floating oil cylinder 1; the other way passes through the second rodless chamber oil circuit L2, and then overcomes the back pressure of the second check valve 8 to flow to the rodless chamber of the second floating oil cylinder 2. This back pressure design and total oil circuit design can ensure that the pressure oil is distributed to the two oil cylinders more smoothly and evenly.

[0068] In this embodiment, the floating cylinder hydraulic system further includes a pressure reducing valve 6 connected in series with the third one-way valve 9. The pressure reducing valve 6 is closer to the pressure oil circuit P than the third one-way valve 9. Figure 2 In the embodiment, when the pressure oil in the pressure oil circuit P flows in the rodless chamber total oil circuit L, it first passes through the pressure reduction of the pressure reducing valve 6, is output with a stable oil pressure after the pressure reduction, and is then evenly distributed to the rodless chambers of the two oil cylinders. The rodless chambers of the two oil cylinders use the pressure reduction output pressure of the pressure reducing valve as a reference to push the piston rod to extend steadily, thereby achieving a smooth and controllable extension of the oil cylinder. If the pressure of the pressure oil in the pressure oil circuit P is too high, when it flows in the rodless chamber total oil circuit L, the oil part that exceeds the overflow pressure of the overflow valve 15 can overflow back to the oil.

[0069] Among them, the rod chamber of each oil cylinder can control the return oil or be supplied with oil through the telescopic control reversing valve 3. When supplying oil to the rodless chamber of the oil cylinder to drive the oil cylinder to extend steadily, the telescopic control reversing valve 3 can be switched to Figure 2 The valve is in the middle position as shown. The Y-type function of the valve in the middle position allows the oil in the rod chambers of the two cylinders to return to the tank together.

[0070] Specifically, in this embodiment, the telescopic control reversing valve 3 as an example adopts a three-position four-way valve and includes a reversing valve oil return port on one side, a reversing valve oil inlet port connected to the pressure oil circuit P, and a first working oil port connected to the rod chamber of the first floating oil cylinder 1 and a second working oil port connected to the rod chamber of the second floating oil cylinder 2 on the other side. In this way, Figure 2 When the telescopic control reversing valve 3 is switched to the left position, the pressure oil will be supplied to the rod chamber of the second floating cylinder 2, and the oil in the rod chamber of the first floating cylinder 1 will return; when the telescopic control reversing valve 3 is switched to the right position, the pressure oil will be supplied to the rod chamber of the first floating cylinder 1, and the oil in the rod chamber of the second floating cylinder 2 will return; when the telescopic control reversing valve 3 is switched to the middle position, the oil in the rod chambers of the two cylinders will return together.

[0071] The pressure oil circuit P can be the system's main oil supply circuit or a pumping pressure oil circuit with a separate hydraulic pump. In this embodiment, the floating cylinder hydraulic system further includes a hydraulic pump 16, which is used to pump hydraulic oil and deliver it to the pressure oil circuit P. That is, the floating cylinder hydraulic system has an independent hydraulic pump, which can more reliably and independently control the floating cylinder action.

[0072] In order to realize the connection between the rodless chambers of the two oil cylinders, that is, to realize the floating function of the oil cylinders, in this embodiment, the first side oil port of the first locking reversing valve 4 is connected to the rodless chamber of the first floating oil cylinder 1, and the first side oil port of the second locking reversing valve 5 is connected to the rodless chamber of the second floating oil cylinder 2. On this basis, the floating connecting oil circuit can be connected to the second side oil port of the first locking reversing valve 4 and the second side oil port of the second locking reversing valve 5, as shown in FIG. Figure 2 In this way, when the first locking reversing valve 4 and the second locking reversing valve 5 are in the conducting state, the first rodless chamber oil circuit L1 and the second rodless chamber oil circuit L2 can realize oil intercommunication through the conducting first locking reversing valve 4, the second locking reversing valve 5 and the floating connection oil circuit.

[0073] Figure 2 A damper 10 is also specially provided in the floating connection oil circuit to make the oil flow between the rodless chambers of the two cylinders slower and more stable, that is, the floating is softer.

[0074] The first locking reversing valve 4 and the second locking reversing valve 5 can be conventional switch solenoid valves, but in this embodiment, a reversing valve structure is particularly adopted. The two have the same structure and include a hydraulic locking position (i.e. Figure 2In the hydraulic locking position, the hydraulic oil can flow from the second side oil port to the first side oil port and the reverse direction is cut off. In the conduction position, the first side oil port is connected to the second side oil port. In this locking reversing valve structure, it has its own hydraulic locking function and unidirectional conduction function. The added redundant hydraulic locking function further enhances the hydraulic locking of the rodless chamber and prevents oil leakage. The hydraulic locking position of the locking reversing valve has unidirectional flowability, so that the rodless chambers of the two cylinders can be connected without switching the first locking reversing valve 4 and the second locking reversing valve 5 to the conduction position. For example, the first locking reversing valve 4 is switched to the on position and the second locking reversing valve 5 is maintained in the hydraulic locking position. Then, the oil in the rodless chamber of the first floating cylinder 1 can pass through the on position of the first locking reversing valve 4 in the first rodless chamber oil circuit L1, the damping 10 in the floating connection oil circuit, and the hydraulic locking position of the second locking reversing valve 5 in the second rodless chamber oil circuit L2 in sequence, and finally flow to the rodless chamber of the second floating cylinder 2, thereby realizing one-way connection between the two rodless chambers.

[0075] Figure 2 The system can be used for leveling control of the left and right front axle cylinders. At this time, the floating cylinder hydraulic system may include a level sensor (not shown) for detecting the horizontality of the chassis and a controller, and the controller may be configured as follows:

[0076] Receive real-time level signal from level sensor;

[0077] Determine that the absolute value of the real-time horizontal signal is greater than the set horizontal deviation value, and send a chassis leveling signal;

[0078] In response to the chassis leveling signal, the telescopic control reversing valve 3 is controlled to make the pressure oil flow to the rod chamber of the floating oil cylinder on the higher side of the chassis until the real-time level signal returns to zero;

[0079] Synchronously with the telescopic control reversing valve 3, the first locking reversing valve 4 or the second locking reversing valve 5 on the higher side of the chassis is controlled to switch to the conducting position.

[0080] In other words, when one side of the chassis is found to be higher and the other side is lower, the chassis leveling signal can be triggered according to the level signal detected by the level sensor. In this case, the pressure oil can be supplied to the rod chamber of the floating cylinder on the side of the chassis that is higher, so that the chassis on that side is lowered until both sides of the chassis are kept level. It can be seen that the floating cylinder hydraulic system of the present application also has the function of active chassis leveling.

[0081] Furthermore, the controller may be configured as follows:

[0082] In response to the cylinder floating signal, the control pressure oil flows to the rodless chamber of the first floating cylinder 1 through the hydraulic locking position of the first locking reversing valve 4 and flows to the rodless chamber of the second floating cylinder 2 through the hydraulic locking position of the second locking reversing valve 5;

[0083] The first locking reversing valve 4 and the second locking reversing valve 5 are controlled to switch to the conducting position.

[0084] It can be seen that under the command of the cylinder floating signal, oil is first supplied to the rodless chambers of the two cylinders, and at this time, both locking reversing valves can be kept in the hydraulic locking position. After the oil supply is completed, the first locking reversing valve 4 and the second locking reversing valve 5 are directly switched to the conduction position, so that the two-way communication between the rodless chambers of the two cylinders can be achieved, thereby realizing the floating control of the left and right front axle cylinders.

[0085] exist Figure 3 In another embodiment shown, as an example, the first floating cylinder 1 is the left front axle cylinder, and the second floating cylinder 2 is the right front axle cylinder; the floating cylinder hydraulic system may also include a third cylinder 11 and a fourth cylinder 12 fixed to the two ends of the rear axle as rear axle cylinders, the cylinder working oil circuit of the third cylinder 11 is connected to the pressure oil circuit P through the third reversing valve 13, and the cylinder working oil circuit of the fourth cylinder 12 is connected to the pressure oil circuit P through the fourth reversing valve 14. It can be seen that the method of setting fixed cylinders at both ends of the rear axle and floating cylinders at both ends of the front axle can take into account the advantages of stable walking, adjustable chassis level, and higher operation safety. Among them, the cylinder barrels of the third cylinder 11 and the fourth cylinder 12 can be integrated with a balancing valve group for hydraulic locking of the rodless cavity to prevent the cylinder from stalling and losing control when retracting with load.

[0086] The floating cylinder hydraulic system of the present application can be used in engineering machinery with walking function, especially in aerial work machinery. Aerial work machinery is generally composed of a chassis, a turntable, a boom and a platform. The function of the chassis is to move the machinery and fix the machinery when it is stationary, so that the machinery can safely lift the boom. The function of the turntable is to install the boom and its power, hydraulic, electrical and other components. The function of the boom is to transport staff and goods to a certain height. The function of the platform is to provide an operating platform for people and goods, so that people can safely work at high altitudes. In general, a good chassis can provide a safe operating environment for aerial work machinery. The more stable the chassis performance, the higher the load that can be provided under the same boom condition. The chassis must take into account both the moving and fixing of the machinery, and the floating cylinder is a key factor. Through the floating cylinder hydraulic system of the present application, the floating cylinder can be controlled to unlock when the machinery is moved, so that the cylinder floats, and the machinery can pass through the potholes very smoothly.

[0087] The following reference Figure 3 The floating cylinder hydraulic system shown is specifically described in the present application.

[0088] The motor rotates to drive the gear pump (i.e., hydraulic pump 16) to work. The hydraulic oil in the oil tank reaches the gear pump from the filter under the action of pump suction, and enters the rodless chamber of the left and right front axle oil cylinders after passing through the one-way valve, the pressure reducing valve 6, the one-way valve group, and the locking reversing valve under the action of pumping pressure. Another part enters the rod chamber of the left and right front axle oil cylinders after passing through the telescopic control reversing valve 3, and reaches the rod chamber or rodless chamber of the left and right rear axle oil cylinders through the pressure oil oil circuit P.

[0089] When the front axle oil cylinder floating and locking functions are realized, the hydraulic oil passes through the pressure reducing valve, the one-way valve group, the two-position two-way reversing valve, and enters the rodless chamber of the left and right front axle oil cylinders. At this time, the hydraulic system defaults to filling the front axle oil cylinder with hydraulic oil. If the left and right tires of the front axle have a gap from the ground at this time, the hydraulic system defaults to using the pressure of the pressure reducing valve to move the floating oil cylinder to make the tires close to the ground. When the hydraulic pressure fills the floating oil cylinder, it enters the locking state. When the electromagnets Y07 and Y08 are energized at the same time, the rodless chambers of the left and right front axle floating oil cylinders are connected, and the oil cylinders enter the floating state. The damping 10 in the middle can make the floating action softer.

[0090] When the leveling function of the left and right front axle cylinders is realized, when the level sensor detects that the left front chassis is higher than the right front chassis, the electromagnet Y02 is energized, the telescopic control reversing valve 3 moves right, and the hydraulic oil enters the rod chamber of the left front axle cylinder after passing through the reversing valve, the cylinder contracts, the left front axle cylinder descends, and the tire descends. At the same time, the electromagnet Y07 is energized, the return oil of the left front axle cylinder enters the rodless chamber of the right front axle cylinder, the right front axle cylinder extends, the right front axle tire rises, and the left and right front axles of the chassis reach a horizontal state. Similarly, when the level sensor detects that the right front chassis is higher than the left front chassis, the electromagnet Y01 is energized, the reversing valve moves to the left, and the hydraulic oil enters the rod chamber of the right front axle cylinder through the reversing valve. The cylinder contracts, the right front axle cylinder descends, and the tire descends. At the same time, the electromagnet Y08 is energized, and the return oil of the right front axle cylinder enters the rodless chamber of the left front axle cylinder. The left front axle cylinder extends, the left front axle tire rises, and the left and right front axles of the chassis reach a horizontal state.

[0091] When the leveling function of the left and right rear axle cylinders is realized, when the level sensor detects that the rear of the chassis is in an uneven state, the left and right rear axle cylinders are controlled separately to adjust the level state. For example, when the left rear chassis is higher than the horizontal state, the electromagnet Y04 is energized, the reversing valve moves to the right, the rod cavity of the left rear axle floating cylinder enters, and the floating cylinder automatically descends until it reaches the horizontal position.

[0092] In summary, the floating cylinder hydraulic system of the present application can realize the floating and locking of the cylinder, and also solves the risk of hydraulic oil leakage and exhaust difficulty of the single-acting cylinder, as well as the possible major risk of tipping over of the aerial work machinery caused by air in the floating cylinder. The front and rear axle cylinders can be controlled separately, especially when the boom is in working state, the floating cylinder has been locked, and when the aerial work machinery is walking and encounters uneven ground, the horizontal state of the chassis can be automatically adjusted. The aerial work machinery can adjust its posture by itself without the boom having to be lowered again, which improves the working efficiency of the aerial work machinery and solves the shortcoming that the chassis of the aerial work machinery cannot be leveled.

[0093] Based on the same purpose, the present application also discloses another floating cylinder hydraulic system. Figure 4 As shown, in a specific embodiment, the floating cylinder hydraulic system includes:

[0094] The left front axle cylinder 20, the left front control valve group of the left front axle cylinder 20 includes a left front reversing valve 21 for switching and controlling the extension and retraction of the left front axle cylinder 20; and

[0095] The right front axle cylinder 25, the right front control valve group of the right front axle cylinder 25 includes a right front reversing valve 26 for switching and controlling the extension and retraction of the right front axle cylinder 25;

[0096] Among them, a left front short-circuit oil circuit is connected between the rod chamber and the rodless chamber of the left front axle cylinder 20, and the left front control valve group includes a left front on-off valve for on-off control of the left front short-circuit oil circuit. A right front short-circuit oil circuit is connected between the rod chamber and the rodless chamber of the right front axle cylinder 25, and the right front control valve group includes a right front on-off valve for on-off control of the right front short-circuit oil circuit.

[0097] It can be seen that in the floating cylinder hydraulic system of the present application, both the left front axle cylinder 20 and the right front axle cylinder 25 adopt double-acting cylinders, that is, both the rod chamber and the rodless chamber can supply oil, which are controlled by the left front reversing valve 21 and the right front reversing valve 26 respectively, which solves the risk of hydraulic oil leakage and exhaust difficulty of the single-acting cylinder, and the possibility that the floating cylinder will overturn the aerial work machinery due to air. More importantly, the left front short-circuit oil circuit and its left front on-off valve are connected between the rod chamber and the rodless chamber of the left front axle cylinder 20, and the right front short-circuit oil circuit and its right front on-off valve are connected between the rod chamber and the rodless chamber of the right front axle cylinder 25. In this way, by controlling the on-off of the short-circuit oil circuit, the floating or locking of the cylinder can be achieved. In addition, by switching and controlling the left front reversing valve 21 and the right front reversing valve 26, the leveling of the left and right front axle cylinders can also be controlled separately, solving the shortcoming that the chassis of the aerial work machinery cannot be leveled.

[0098] In this embodiment, as an example, the left front short-circuit oil circuit includes:

[0099] The left front rodless chamber bypass oil circuit extends from the left front rodless chamber working oil circuit bypass branch of the left front axle cylinder 20 and is provided with a left front rodless chamber on-off valve 23;

[0100] The left front rod chamber side oil circuit extends from the left front rod chamber working oil circuit side branch of the left front axle oil cylinder 20 and is provided with a left front rod chamber on-off valve 24;

[0101] The left front on-off valve includes a left front rodless chamber on-off valve 23 and a left front rod chamber on-off valve 24 .

[0102] Similarly, the right front short circuit oil circuit may include:

[0103] The right front rodless chamber bypass oil circuit extends from the right front rodless chamber working oil circuit bypass branch of the right front axle cylinder 25 and is provided with a right front rodless chamber on-off valve 28;

[0104] The right front rod chamber side oil circuit extends from the right front rod chamber working oil circuit side branch of the right front axle oil cylinder 25 and is provided with a right front rod chamber on-off valve 29;

[0105] The right front on-off valve includes a right front rodless chamber on-off valve 28 and a right front rod chamber on-off valve 29 .

[0106] It can be seen that when the left front rodless chamber on-off valve 23 and the left front rod chamber on-off valve 24 are both turned on, the left front rodless chamber bypass oil circuit and the left front rod chamber bypass oil circuit are both turned on, that is, the left front short-circuit oil circuit is turned on, and the rodless chamber of the left front axle oil cylinder 20 is connected with the rod chamber, which can realize the floating of the oil cylinder. Similarly, when the right front rodless chamber on-off valve 28 and the right front rod chamber on-off valve 29 are both turned on, the right front rodless chamber bypass oil circuit and the right front rod chamber bypass oil circuit are both turned on, that is, the right front short-circuit oil circuit is turned on, and the rodless chamber of the right front axle oil cylinder 25 is connected with the rod chamber, which can realize the floating of the oil cylinder.

[0107] In this embodiment, Figure 4 The left front rodless chamber on-off valve 23, the left front rod chamber on-off valve 24, the right front rodless chamber on-off valve 28 and the right front rod chamber on-off valve 29 all use two-position two-way solenoid valves and include a hydraulic locking position and a conduction position. In the hydraulic locking position, the hydraulic oil can flow from one side of the solenoid valve to the rodless chamber and is cut off in the reverse direction. In the conduction position, the oil ports on both sides of the solenoid valve are connected. In the hydraulic locking position, the oil leakage of the rod chamber or the rodless chamber can be prevented, and the oil pressure of the chamber can be locked.

[0108] In addition, the left front short-circuit oil circuit and the right front short-circuit oil circuit of this embodiment are hydraulically connected to the return oil circuit, so that during the floating process, the difference between the oil in the rod chamber and the oil in the rodless chamber caused by the difference in the area of ​​the two chambers can be returned or replenished through the return oil circuit. In addition, an adjustable overflow valve (not shown in the figure) can be set in the return oil circuit to ensure the oil pressure of the cavity in the floating state, and the pumping oil circuit of the replenishment pump can also be connected to the rod chamber. Similarly, a back pressure valve, such as a one-way valve for locking the oil reflux, can also be set in the return oil circuit.

[0109] like Figure 4 As shown, the floating cylinder hydraulic system includes:

[0110] The hydraulic pump 16 is used to pump hydraulic oil and deliver it in parallel to the oil inlets of the left front reversing valve 21 and the right front reversing valve 26 .

[0111] The floating oil cylinder can be connected to the vehicle pressure oil circuit and supplied with oil through the vehicle pressure oil circuit, but it can also be supplied with oil separately, which is more convenient to control, such as the embodiment of the present invention. Figure 4 as shown in .

[0112] Specifically, the floating cylinder hydraulic system may further include a controller configured to:

[0113] Control and start the hydraulic pump 16;

[0114] The left front reversing valve 21 and the right front reversing valve 26 are switched and controlled respectively, so that the piston of the left front axle oil cylinder 20 and the piston of the right front axle oil cylinder 25 respectively perform a number of full stroke movements;

[0115] The left front on-off valve and the right front on-off valve are controlled so that the left front short-circuit oil circuit and the right front short-circuit oil circuit are both kept in a conducting state.

[0116] On the basis of the hydraulic pressure of the above-mentioned floating cylinder hydraulic system, the floating of the cylinder can be realized through the controller. That is, first start the hydraulic pump 16 to pump the hydraulic oil to the respective oil inlets of the left front reversing valve 21 and the right front reversing valve 26, wherein the overpressure hydraulic oil can overflow through the overflow valve 15. Then, switch and control the two reversing valves so that the cylinder piston makes a full cylinder stroke to remove the air in the cavity. Finally, control the left front on-off valve and the right front on-off valve so that the left front short-circuit oil circuit and the right front short-circuit oil circuit are both kept in the conducting state, thereby realizing the floating state of the two floating cylinders.

[0117] It should be noted that for a single oil cylinder, since hydraulic oil is only actively passed to the rodless chamber, the air in the rod chamber must be exhausted. Move the piston from one extreme position of the oil chamber to the other extreme position, so that the gas in the cylinder chamber, especially the gas in the rod chamber, can be exhausted. A single reciprocating motion of the piston between the two extreme positions of the oil chamber is the full stroke motion of the piston. Repeating the full stroke motion of the piston several times can completely complete the exhaust action.

[0118] During the exhaust control process, i.e., the left front reversing valve 21 and the right front reversing valve 26 are switched and controlled respectively, so that the pistons of the left front axle oil cylinder 20 and the right front axle oil cylinder 25 respectively make several full stroke movements, the left front on-off valve and the right front on-off valve should also be controlled so that the left front short-circuit oil circuit and the right front short-circuit oil circuit remain cut off. That is, during the exhaust process, the rod chamber and the rodless chamber cannot be connected.

[0119] The above-mentioned floating cylinder hydraulic system can be applied to aerial work machinery. The left front axle cylinder 20 and the right front axle cylinder 25 are installed at both ends of the front axle of the aerial work machinery as floating cylinders. The aerial work machinery also includes a left rear axle cylinder and a right rear axle cylinder fixed at both ends of the rear axle.

[0120] The following reference Figure 4 The floating cylinder hydraulic system shown in the figure is explained in detail.

[0121] The rotation of the motor drives the gear pump serving as the hydraulic pump 16 to work. After the hydraulic oil passes through the gear pump from the filter, the proportional electromagnets of the left front reversing valve 21 and the right front reversing valve 26 are energized, and the hydraulic oil enters the rod chamber and the rodless chamber of the front axle cylinder.

[0122] 1) Locking and floating of the front axle cylinder. The left and right front axle cylinders need to move through the full stroke more than three times to expel the air inside the cylinders. When the left and right front axle cylinders are filled with hydraulic oil, they enter the locked state by default. Front axle cylinder floating. Specifically for the floating of the left front axle cylinder 20, the electromagnets Y03 and Y04 are energized at the same time, and the rod chamber and the rodless chamber of the left front axle cylinder 20 are connected, so that the left front axle cylinder 20 can float. For the floating of the right front axle cylinder 25, the electromagnets Y07 and Y08 are energized at the same time, and the rod chamber and the rodless chamber of the right front axle cylinder 25 are connected, so that the right front axle cylinder 25 can float.

[0123] 2) Leveling of the front axle cylinder. When the level sensor detects that the left front axle chassis is below the horizontal, the electromagnet Y01 is energized, the hydraulic oil enters the rodless chamber of the left front axle cylinder through the balance valve, the cylinder extends, and the left front axle tire rises to a horizontal position. When the level sensor detects that the right front axle tire is below the horizontal, the electromagnet Y05 is energized, the hydraulic oil enters the rodless chamber of the right front axle cylinder through the balance valve, the cylinder extends, and the right front axle tire rises to a horizontal position. When the level sensor detects that the left front axle tire is above the horizontal, the electromagnet Y02 is energized, the hydraulic oil enters the rod chamber of the left front axle cylinder through the balance valve, the cylinder retracts, and the left front axle tire drops to a horizontal position. When the level sensor detects that the right front axle tire is above the horizontal, the electromagnet Y06 is energized, the hydraulic oil enters the rod chamber of the right front axle cylinder through the balance valve, the cylinder retracts, and the right front axle tire rises to a horizontal position.

[0124] The present application realizes the floating and locking of the cylinder while solving the risk of hydraulic oil leakage and exhaust difficulty of the single-acting cylinder. The air left in the floating cylinder may cause the aerial work machinery to tip over. In addition, the leveling of the left and right front axle cylinders can be controlled independently, solving the shortcoming that the aerial work machinery chassis cannot be leveled.

[0125] In short, the floating cylinder hydraulic system of the present application can achieve the floating and locking of the cylinder, while solving the risk of hydraulic oil leakage and exhaust difficulties of the single-acting cylinder. The front and rear axle cylinders can be controlled separately, especially when the boom is in working condition, the floating cylinder has been locked, and when the aerial work machine is walking, if it encounters a bumpy ground, it can automatically adjust the horizontal state of the chassis, so that the boom does not need to be lowered again, and the aerial work machine can adjust its posture by itself, which improves the working efficiency of the aerial work machine and solves the shortcoming that the chassis of the aerial work machine cannot be leveled.

[0126] In the description of the present application, 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 application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0127] In this application, 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 connection; 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 this application can be understood according to specific circumstances.

[0128] 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 application. 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.

Claims

1. A floating cylinder hydraulic system, characterized in that: The floating cylinder hydraulic system comprises: A left front axle oil cylinder (20), wherein the left front control valve group of the left front axle oil cylinder (20) comprises a left front reversing valve (21) for switching and controlling the extension and retraction of the left front axle oil cylinder (20); and A right front axle oil cylinder (25), wherein the right front control valve group of the right front axle oil cylinder (25) comprises a right front reversing valve (26) for switching and controlling the extension and retraction of the right front axle oil cylinder (25); Among them, a left front short-circuit oil circuit is connected between the rod chamber and the rodless chamber of the left front axle cylinder (20), and the left front control valve group includes a left front on-off valve for on-off control of the left front short-circuit oil circuit; a right front short-circuit oil circuit is connected between the rod chamber and the rodless chamber of the right front axle cylinder (25), and the right front control valve group includes a right front on-off valve for on-off control of the right front short-circuit oil circuit.

2. The floating cylinder hydraulic system according to claim 1, characterized in that: The left front short-circuit oil circuit comprises: A left front rodless chamber bypass oil circuit extends from a left front rodless chamber working oil circuit bypass branch of the left front axle oil cylinder (20) and is provided with a left front rodless chamber on-off valve (23); A left front rod chamber bypass oil circuit extends from a left front rod chamber working oil circuit bypass branch of the left front axle oil cylinder (20) and is provided with a left front rod chamber on-off valve (24); Wherein, the left front on-off valve comprises the left front rodless chamber on-off valve (23) and the left front rod chamber on-off valve (24).

3. The floating cylinder hydraulic system according to claim 2, characterized in that: The right front short-circuit oil circuit comprises: A right front rodless chamber bypass oil circuit extends from a right front rodless chamber working oil circuit bypass branch of the right front axle oil cylinder (25) and is provided with a right front rodless chamber on-off valve (28); A right front rod chamber bypass oil circuit extends from a right front rod chamber working oil circuit bypass branch of the right front axle oil cylinder (25) and is provided with a right front rod chamber on-off valve (29); Wherein, the right front on-off valve comprises the right front rodless chamber on-off valve (28) and the right front rod chamber on-off valve (29).

4. The floating cylinder hydraulic system according to claim 3, characterized in that: The left front rodless chamber on-off valve (23), the left front rod chamber on-off valve (24), the right front rodless chamber on-off valve (28) and the right front rod chamber on-off valve (29) are all two-position two-way solenoid valves and include a hydraulic locking position and a conducting position. In the hydraulic locking position, hydraulic oil can flow from one side of the solenoid valve to the rodless chamber and be blocked in the reverse direction. In the conducting position, the oil ports on both sides of the solenoid valve are connected.

5. The floating cylinder hydraulic system according to claim 1, characterized in that: The left front short-circuit oil circuit and the right front short-circuit oil circuit are both hydraulically connected to the oil return circuit.

6. The floating cylinder hydraulic system according to claim 5, characterized in that: An adjustable overflow valve and / or back pressure valve is provided in the oil return line.

7. The floating cylinder hydraulic system according to any one of claims 1 to 6, characterized in that: The floating cylinder hydraulic system comprises: A hydraulic pump (16) is used to pump hydraulic oil and deliver it in parallel to the oil inlets of the left front reversing valve (21) and the right front reversing valve (26).

8. The floating cylinder hydraulic system according to claim 7, characterized in that: The floating cylinder hydraulic system includes a controller configured to: Controlling and starting the hydraulic pump (16); The left front reversing valve (21) and the right front reversing valve (26) are switched and controlled respectively, so that the piston of the left front axle oil cylinder (20) and the piston of the right front axle oil cylinder (25) respectively perform a number of full stroke movements; The left front on-off valve and the right front on-off valve are controlled so that the left front short-circuit oil circuit and the right front short-circuit oil circuit are both kept in a conducting state.

9. The floating cylinder hydraulic system according to claim 8, characterized in that: The left front reversing valve (21) and the right front reversing valve (26) are switched and controlled respectively, so that the piston of the left front axle oil cylinder (20) and the piston of the right front axle oil cylinder (25) respectively perform a number of full stroke movements, and further comprising: The left front on-off valve and the right front on-off valve are controlled so that the left front short-circuit oil circuit and the right front short-circuit oil circuit remain cut off.

10. A high-altitude working machine, characterized in that: The aerial work machine comprises a floating cylinder hydraulic system according to any one of claims 1 to 9, wherein the left front axle cylinder (20) and the right front axle cylinder (25) are installed at both ends of the front axle of the aerial work machine as floating cylinders, and the aerial work machine further comprises a left rear axle cylinder and a right rear axle cylinder fixed at both ends of the rear axle.

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