CN201882878U - Elevation operation vehicle and platform leveling hydraulic system thereof - Google Patents

Abstract

The utility model discloses a platform leveling hydraulic system, which comprises a leveling oil cylinder, a boom section luffing oil cylinder, a priority valve, a first flow control valve used to control the liquid inlet volume of two cavities of the leveling oil cylinder, and a first flow control valve used to control the boom section The second flow control valve for the liquid inlet of the two chambers of the luffing cylinder; the oil inlet of the priority valve is connected with the system pressure oil circuit, its main oil port is connected with the oil inlet of the first flow control valve, and the second oil port is connected with the second oil port The oil inlet port of the second flow control valve is connected; the first control oil port whose opening degree of the main oil port is controlled to increase is connected with the oil outlet port of the first flow control valve, and the opening degree of the second oil port is controlled to be increased The changed second control oil port communicates with the oil inlet port of the first flow control valve. The system pressure oil first meets the flow requirements of the leveling cylinder, which can effectively avoid the phenomenon of leading or lagging platform leveling. On this basis, the utility model also provides an elevating work vehicle with the platform leveling hydraulic system.

Description

Elevating work vehicle and its platform leveling hydraulic system

technical field

The utility model relates to the technical field of construction machinery, in particular to an elevating work vehicle and a platform leveling hydraulic system thereof.

Background technique

In various high-altitude operations and fire rescue, elevating work vehicles are widely used due to their good mobility. For example, climbing platform fire trucks.

Existing platform fire trucks are equipped with a lifting platform, and the control platform reaches the working position through the extension operation of the boom, so that firefighters can climb to save high-rise buildings, oil tank fires or rescue trapped people. At present, the jibs of elevating vehicles are mostly composed of two or more folding arms, and the angle changes between the platform and the jibs and the connecting hinge points of each jib are realized by the expansion and contraction of the corresponding luffing cylinders. Obviously, its boom system is one of the key components that determine the performance of the vehicle. Please refer to FIG. 1 , which shows a schematic diagram of the overall structure of a conventional elevating work vehicle.

As shown in Figure 1, under the action of the first luffing cylinder 10, the second luffing cylinder 20, and the crank arm luffing cylinder 30, each joint arm can perform corresponding luffing around hinge points A, B, and C respectively, To ensure that the working platform 50 reaches the predetermined working position. As we all know, in the process of raising and lowering the working platform 50 by the amplitude of each jib, theoretically, the bottom of the working platform 50 is required to be in a horizontal state all the time, that is, θ ₁ =0; to ensure the stability and safety of the working platform. Limited by the structure of the jib system itself, its crank arm (top section arm) is generally short (2-3m), and when the luffing speed is fast, the angle (θ ₂ ) changes greatly. Obviously, if the adjustment of the working platform Leading (θ ₁ >0) or lagging (θ ₁ <0) will inevitably affect the reliability and safety of the product.

Based on the above problems, the prior art utilizes a hydraulic-electric automatic leveling system to control the expansion and contraction of the leveling cylinder 40 hinged between the work platform and the crank arm, so as to avoid the frequent occurrence of leading or lagging in leveling. Please refer to FIG. 2 , which shows a hydraulic schematic diagram of a platform leveling system of an existing elevating work vehicle.

In the existing platform leveling system, the crank arm luffing cylinder 30 and the leveling oil cylinder 40 are separately controlled by two control valves, as shown in Figure 2, the crank arm luffing cylinder 30 is controlled by the proportional valve 60 on the left in the valve group , the leveling oil cylinder is controlled by the right servo valve 70 in the valve group. When the crank arm makes a luffing motion (that is, the crank arm luffing cylinder extends or retracts), the angle of the work platform 50 changes (that is, the platform no longer maintains a horizontal state), and the angle sensor installed at the bottom of the work platform 50 sends a signal at this time. signal, the signal is fed back to the servo valve controller, and the controller receives an instruction to control the opening of the servo valve 70, and the leveling cylinder 40 acts, so that the working platform 50 moves toward the trend of θ ₁ → 0 until the working platform 50 is in a horizontal state , the servo valve 70 is closed.

From the above analysis of the leveling hydraulic principle, it can be seen that the system independently controls the movement of the crank arm luffing cylinder 30 and the leveling cylinder 40 through two hydraulic valves. The disadvantages of this technology are mainly manifested in the following three aspects:

1. The flow rate of the leveling cylinder is not only affected by the opening size of the servo valve, but also affected by the change of the load pressure, so a stable flow rate cannot be guaranteed.

2. The opening size of the leveling servo valve is limited by the speed of the crank arm luffing. When the crank arm jitters or the speed changes greatly, the leveling will also shake and level unstable.

3. The synchronization of leveling is completely controlled by electricity. Since the sensor obtains the signal and the controller sends out the command, it takes a response time. This response time directly leads to the lag of the leveling cylinder movement.

In view of this, it is urgent to optimize the design of the existing platform leveling system to effectively overcome the above defects.

Utility model content

In view of the above-mentioned defects, the technical problem solved by the utility model is to provide a platform leveling hydraulic system. When the vehicle is performing boom joint luffing operations, the system pressure oil first meets the flow requirements of the leveling cylinder, which can effectively avoid platform leveling. Leading or lagging phenomenon appears to ensure smooth and reliable leveling process. On this basis, the utility model also provides an elevating work vehicle with the platform leveling hydraulic system.

The platform leveling hydraulic system provided by the utility model is used to control the platform hinged on the jacking arm to maintain a horizontal state. The system includes a leveling oil cylinder and an arm section luffing oil cylinder; The first flow control valve for the liquid intake of the chamber and the second flow control valve for controlling the liquid intake of the two chambers of the boom joint luffing cylinder; the oil inlet of the priority valve is connected with the system pressure oil circuit, and its main The oil port is connected with the oil inlet port of the first flow control valve, and the second oil port is connected with the oil inlet port of the second flow control valve; the first control oil port whose opening of the main oil port is controlled to increase tends to be connected with the said The oil outlet of the first flow control valve is connected, and the second control oil port, which controls the opening of the second oil port to increase, is connected with the oil inlet of the first flow control valve.

Preferably, the first control oil port of the priority valve communicates with the oil inlet port of the first flow control valve, and the distance between the oil inlet port of the first flow control valve and the first control oil port The damping is greater than the damping between the oil inlet port of the first flow control valve and the second control oil port.

Preferably, it also includes a shuttle valve arranged between the two oil outlets of the first flow control valve and the two cavities of the leveling oil cylinder, and its two oil inlets are respectively connected to the two chambers of the leveling oil cylinder. chamber, and its oil outlet communicates with the first control oil port of the priority valve.

Preferably, it also includes an overflow valve arranged between the liquid inlet line of the rodless chamber of the leveling cylinder and the system oil return line.

Preferably, it also includes a first balance valve arranged on the liquid inlet pipeline of the rodless chamber of the leveling oil cylinder, and its control oil port communicates with the rod chamber of the leveling oil cylinder.

Preferably, it also includes a second balance valve and a third balance valve arranged on the rodless chamber and the rod chamber inlet pipeline of the jib luffing cylinder, the control oil port of the second balance valve is connected to the The liquid inlet pipeline of the rod cavity of the jib luffing cylinder is connected, and the control oil port of the third balance valve is connected with the liquid inlet pipeline of the rodless cavity of the jib luffing cylinder.

Preferably, the first flow control valve and the second flow control valve are specifically servo valves.

Preferably, the first flow control valve and the second flow control valve are specifically proportional valves.

The elevating operation vehicle provided by the utility model includes an arm frame connected to the chassis, a platform hinged with the top section arm of the arm frame, and a platform leveling hydraulic system as described above.

The platform leveling hydraulic system provided by the utility model adopts two flow control valves to control the liquid intake of the two cavities of the leveling cylinder and the two cavities of the jib luffing cylinder respectively, and a priority valve is set before the two flow control valves; That is to say, the priority valve is set between the system pressure oil circuit and the liquid inlets of the two flow control valves. According to the flow demand of the circuit, the secondary oil port of the priority valve is connected with the oil inlet port of the second flow control valve to supply oil to the boom joint luffing cylinder. Compared with the prior art, the utility model establishes the oil supply relationship between the leveling oil cylinder and the jib luffing oil cylinder through the priority valve. Flow requirements can effectively avoid the phenomenon of platform leveling leading or lagging, and the leveling process is stable and reliable.

In addition, during the entire luffing operation process, when the spool of the priority valve is in the balance position, the feedback pressure of the first control oil port plus the pre-tightening force of the spring is equal to the feedback pressure of the second control oil port, that is, the first flow control valve The front and rear pressure difference is equal to the spring preload of the priority valve, which is a constant. Therefore, the flow through the first flow control valve is not affected by the load pressure, and is only proportional to the opening area of its spool. Even when the jib section vibrates or the speed changes greatly, the leveling will not cause jitter and uneven leveling. stabilization phenomenon. On the other hand, the synchronization of the leveling system provided by the utility model is not completely controlled by electricity, and the circuit itself can improve the synchronization effect through the priority valve and the feedback oil circuit, with fast response speed and high reliability, which can effectively avoid electrical control. The existing response time causes the problem of lag in the movement of the leveling cylinder.

In the preferred solution of the present utility model, the first control oil port of the priority valve communicates with the oil inlet port of the first flow control valve, that is, the first control oil port adds one feedback control oil to reduce the load due to leveling. The vibration of the spool caused by the change of the valve further improves the stability of the system.

In another preferred solution of the present utility model, a shuttle valve is additionally provided between the two oil outlets of the first flow control valve and the two cavities of the leveling oil cylinder, and its two oil inlets are respectively connected to the two chambers of the leveling oil cylinder. The two cavities of the leveling oil cylinder are connected, and its oil outlet is connected with the first control oil port of the priority valve. With such a setting, the flow demand of the oil circuit of the leveling oil cylinder can be satisfied firstly during the process of extending or retracting the oil cylinder, so as to ensure a stable and reliable leveling process.

The platform leveling hydraulic system provided by the utility model is suitable for any kind of elevating operation vehicle, especially suitable for a fire truck for climbing a platform.

Description of drawings

Fig. 1 is the overall structure schematic diagram of existing elevating operation vehicle;

Fig. 2 is the hydraulic principle diagram of the platform leveling system of the existing elevating work vehicle;

Fig. 3 is a working principle diagram of the first embodiment of the platform leveling hydraulic system;

Fig. 4 is a working principle diagram of the second embodiment of the platform leveling hydraulic system.

In Figure 3 and Figure 4:

Leveling oil cylinder 1, jib luffing oil cylinder 2, first flow control valve 3, second flow control valve 4, priority valve 5, oil inlet 51, main oil port 52, secondary oil port 53, first control oil port 54. The second control oil port 55, the shuttle valve 6, the relief valve 7, the first balance valve 81, the second balance valve 82, and the third balance valve 83.

Detailed ways

The core of the utility model is to provide a platform leveling hydraulic system, so that when the vehicle is performing boom joint luffing operations, the system pressure oil first meets the flow requirements of the leveling cylinder, which can effectively avoid the platform leveling ahead or lag If the phenomenon occurs, ensure that the leveling process is stable and reliable. The specific implementation will be described in detail below in conjunction with the accompanying drawings.

Please refer to FIG. 3 , which is a working principle diagram of the first embodiment of the platform leveling hydraulic system.

The platform leveling hydraulic system is used to control the leveling of the platform hinged on the jacking boom, and specifically includes: leveling cylinder 1, jib luffing cylinder 2, two flow control valves (the first flow control valve 3 and the second flow control valve 4) and priority valve 5. Same as the prior art, in this solution, the leveling cylinder 1 is arranged between the platform and the top jib of the jib, and the jib luffing cylinder 2 is used to adjust the luffing of the top jib according to the manipulation signal.

Among them, the first flow control valve 3 is used to control the liquid intake volume of the two chambers of the leveling cylinder 1, and through the displacement of the first flow control valve 3, the system pressure oil circuit P and the system oil return circuit T are connected with the leveling oil cylinder 1. The conduction relationship between the rod cavity and the rodless cavity: the pressure oil circuit P is connected with the rod cavity of the leveling cylinder 1, and the rodless cavity of the leveling cylinder 1 is connected with the oil return circuit T, then the leveling cylinder 1 is retracted; the pressure oil circuit P is connected with the rodless chamber of the leveling cylinder 1, and the rod chamber of the leveling cylinder 1 is connected with the oil return circuit T, then the leveling cylinder 1 is extended.

In the same way, the second flow control valve 4 is used to control the liquid intake volume of the two chambers of the luffing cylinder 2, and the system pressure oil circuit P and the system oil return oil circuit T are connected to the arm through the displacement of the second flow control valve 4. The conduction relationship between the rod chamber and the rodless chamber of the luffing cylinder 2: the pressure oil circuit P is connected with the rod chamber of the luffing cylinder 2, the rodless chamber of the luffing cylinder 2 is connected with the oil return If the oil passage T is connected, the jib luffing cylinder 2 is retracted; the pressure oil passage P is connected to the rodless chamber of the jib luffing cylinder 2, and the rod chamber of the jib luffing cylinder 2 is connected to the return oil passage T, then The boom luffing cylinder 2 stretches out. As shown in Fig. 3, the first flow control valve 3 and the second flow control valve are preferably servo valves, which have a transition position between the two working positions, that is, there is no dead zone in the middle position, and the response frequency is relatively high. It should be understood that the first flow control valve 3 and the second flow control valve may also be proportional valves, as long as they can meet the flow direction and flow control requirements of the corresponding oil cylinders.

Among them, the oil inlet 51 of the priority valve 5 is connected with the system pressure oil circuit P, and its main oil port 52 is connected with the oil inlet of the first flow control valve 4, which preferentially meets the flow demand of the oil circuit of the leveling oil cylinder; secondly, the oil port 53 communicates with the oil inlet of the second flow control valve 4 to supply oil to the jib luffing cylinder 2, that is, the excess flow is supplied to the oil circuit of the jib luffing cylinder through the secondary oil port 53. Obviously, the oil supply relationship between the leveling cylinder 1 and the jib luffing cylinder 2 is established through the priority valve. When the vehicle is performing luffing operations, the system pressure oil first meets the flow requirements of the leveling cylinder 1, which can effectively avoid platform The phenomenon of leveling leading or lagging appears, and the leveling process is stable and reliable.

In addition, as shown in the figure, the first control oil port 54 whose opening degree of the main oil port 52 is controlled to increase tends to communicate with the oil outlet of the first flow control valve 4, and the opening degree of the secondary oil port 53 is controlled to increase. The second control oil port 55 with a changing trend communicates with the oil inlet port of the first flow control valve 4 . That is to say, the first control oil port 54 is the pressure feedback port after the valve of the first flow control valve 4 (the pressure in the working chamber of the leveling cylinder 1 is fed back to this oil port), and the second control oil port 55 is the pressure feedback port of the first flow control valve 4 . Pressure feedback port after the valve (the oil supply pressure of the main oil port 52 of the priority valve is fed back to this oil port). When the spool of the priority valve 5 is in the balance position, the feedback pressure of the first control oil port 54 plus the pre-tightening force F _k of the spring is equal to the feedback pressure of the second control oil port 55, that is, the front and rear of the first flow control valve 4 The pressure difference is equal to the spring preload _Fk of the priority valve 5, which is a constant. Therefore, the flow through the first flow control valve 4 is not affected by the load pressure, and is only proportional to the opening area of the spool.

When the vehicle is performing boom luffing operations, when the jib luffing speed is fast and the leveling lags behind, the angle θ ₁ (as shown in Figure 1) will increase negatively (that is, θ ₁ <0), and the leveling sensor The return signal (current or voltage) of the priority valve 5 will increase, thereby controlling the opening area of the first flow control valve 4 to increase; in this state, the pressure before the valve decreases, that is, the feedback pressure of the second control oil port 55 of the priority valve 5 decreases At this time, the feedback pressure of the first control oil port 54 plus the spring pre-tightening force F _k is greater than the feedback pressure of the second control oil port 55, and the spool of the priority valve 5 moves downward (that is, moves to the no-spring cavity), The opening of the main oil port 52 increases, the flow rate increases, the opening of the secondary oil port 53 decreases, and the flow rate decreases, so that the movement speed of the leveling cylinder 1 is accelerated, and the movement speed of the jib luffing cylinder 2 is slowed down, thereby quickly eliminating the leveling lag The phenomenon.

Conversely, when the leveling is advanced, the angle θ ₁ (as shown in Figure 1) will increase positively (ie θ ₁ >0), and the return signal (current or voltage) of the leveling sensor will decrease, thereby controlling the first flow rate The opening area of the control valve 4 decreases; in this state, the pressure before the valve increases, and the spool of the priority valve 5 moves upward (that is, moves to the spring chamber), so that the movement speed of the leveling cylinder 1 slows down, and the jib luffing cylinder 2 The speed of movement is accelerated, thereby quickly eliminating the phenomenon of leveling lead.

The analysis of the above working principle shows that the synchronization of this scheme is not completely controlled by electricity. The circuit itself can improve the synchronization effect through the priority valve and the feedback oil circuit. The response speed is fast and the reliability is high, which can effectively avoid the response time of the electric control. A problem that caused the movement of the leveling cylinder to lag.

In order to ensure that the oil cylinder is extended or retracted, the flow demand of the oil circuit of the leveling cylinder can be met first, and the leveling process is stable and reliable. As shown in Figure 3, the shuttle valve 6 between the two oil outlets of the first flow control valve 4 and the two cavities of the leveling cylinder 1 in this scheme, its two oil inlets are connected with the two chambers of the leveling cylinder 1 respectively. The cavity is connected, and its oil outlet is connected with the first control oil port 54 of the priority valve 5 . The shuttle valve 6 is used in this circuit, which can effectively optimize the pipeline design and reduce the assembly cost.

In addition, a relief valve 7 is provided between the rodless chamber inlet line of the leveling cylinder 1 and the system oil return line T to further improve safety and reliability.

In order to further make the load work smoothly, as shown in Figure 3, balance valves are installed on the leveling cylinder 1 and the jib luffing cylinder 2 of this solution to generate back pressure, prevent the load from falling due to its own weight, and make the movement stable. Specifically, a first balance valve 81 is provided on the liquid inlet line of the rodless chamber of the leveling cylinder 1, and its control oil port communicates with the rod chamber of the leveling cylinder 1; The second balance valve 82 is set on the liquid pipeline, and its control oil port communicates with the liquid inlet pipeline of the rod chamber of the boom joint luffing cylinder 2; Valve 83, its control oil port is in communication with the rodless chamber inlet pipeline of the jib luffing cylinder 2.

Please refer to FIG. 4 , which is a working principle diagram of the second embodiment of the platform leveling hydraulic system.

The basic structure and working principle of this embodiment are the same as those of the first embodiment. Compared with the first embodiment, the difference of this embodiment is: the first control oil port 54 of the priority valve 5 and the oil inlet 51 of the first flow control valve 4 connected, and the damping between the oil inlet of the first flow control valve 4 and the first control oil port 54 is greater than the damping between the oil inlet of the first flow control valve 4 and the second control oil port 55 . In such a design, the pre-valve pressure of the first flow control valve 4 participates in the feedback of the first control oil port 54, without affecting the feedback pressure of the first control oil port 54, the spring preload F _k and the second control oil port 55 On the basis of the balance relationship established before the feedback pressure, the jitter of the priority valve 5 spool caused by the change of the leveling load can be reduced. During the leveling process, the displacement of the spool of the priority valve 5 can be dynamically adjusted based on the change of the pre-valve pressure of the first flow control valve 4, so as to further improve the working stability of the system.

In addition to the aforementioned platform leveling hydraulic system, this solution also provides an elevating work vehicle, including a boom connected to the chassis and a platform hinged with the top section arm of the boom, and also includes the platform leveling as mentioned above Hydraulic system. Please refer to Figure 1 for details.

It should be noted that the chassis, arm frame, platform and other functional components of the elevating work vehicle are the same as those of the prior art, and those skilled in the art can fully realize it based on the prior art, so this article will not repeat them here.

The above is only a preferred embodiment of the utility model, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the utility model, some improvements and modifications can also be made, these improvements and Retouching should also be regarded as the scope of protection of the present utility model.

Claims (9)

1. The platform leveling hydraulic system is used to control the platform hinged to the top section arm to maintain a horizontal state. The system includes a leveling cylinder and a boom section luffing cylinder; it is characterized in that it also includes: The first flow control valve is used to control the liquid intake of the two chambers of the leveling cylinder; The second flow control valve; used to control the liquid intake volume of the two chambers of the luffing cylinder; and Priority valve, its oil inlet is connected with the system pressure oil circuit, its main oil port is connected with the oil inlet of the first flow control valve, and its second oil port is connected with the oil inlet of the second flow control valve; its main oil port is controlled The first control oil port whose opening degree changes in an increasing trend is connected with the oil outlet of the first flow control valve, and the second control oil port whose opening degree changes in an increasing trend is controlled to communicate with the first flow rate control valve. The oil inlet port of the control valve is connected. 2. The platform leveling hydraulic system according to claim 1, wherein the first control oil port of the priority valve communicates with the oil inlet port of the first flow control valve, and the first flow control valve The damping between the oil inlet of the valve and the first control oil port is greater than the damping between the oil inlet of the first flow control valve and the second control oil port. 3. The platform leveling hydraulic system according to claim 1 or 2, characterized in that, it further comprises a valve arranged between the two oil outlets of the first flow control valve and the two cavities of the leveling oil cylinder As for the shuttle valve, its two oil inlets communicate with the two cavities of the leveling oil cylinder respectively, and its oil outlet communicates with the first control oil port of the priority valve. 4 . The platform leveling hydraulic system according to claim 3 , further comprising an overflow valve arranged between the rodless chamber inlet line of the leveling cylinder and the system oil return line. 5 . 5. The platform leveling hydraulic system according to claim 4, further comprising a first balance valve arranged on the rodless cavity inlet pipeline of the leveling oil cylinder, which controls the oil port to be connected to the leveling cylinder. The rod cavity of the oil cylinder is connected. 6. The platform leveling hydraulic system according to claim 5, further comprising a second balance valve and a third balance valve arranged on the rodless chamber and the rod chamber inlet pipeline of the jib luffing cylinder. Balance valve, the control oil port of the second balance valve communicates with the rod cavity inlet pipeline of the boom section luffing cylinder, the control oil port of the third balance valve communicates with the boom section luffing cylinder Rodless chamber inlet line. 7. The platform leveling hydraulic system according to claim 6, wherein the first flow control valve and the second flow control valve are specifically servo valves. 8. The platform leveling hydraulic system according to claim 6, wherein the first flow control valve and the second flow control valve are specifically proportional valves. 9. Elevating work vehicle, comprising a jib connected to the chassis and a platform articulated with the top joint arm of the jib, characterized in that it also includes the platform leveling platform according to any one of claims 1 to 9 Hydraulic system.

Images