Aerial work platform and hydraulic control system thereof

Abstract

The utility model discloses an aerial work platform and a hydraulic control system thereof. The system comprises a hydraulic oil tank, a driving motor used for driving a gear pump, the gear pump, a reversing valve, a bidirectional balance valve, an unloading valve and a throttling element. An inlet of the gear pump is connected with the hydraulic oil tank, and an outlet of the gear pump is connected with a first opening of the reversing valve and a first opening of the unloading valve. A second port of the unloading valve is connected with the throttling element, and the throttling element is connected with a second port of the reversing valve and a hydraulic oil tank; a third port and a fourth port of the reversing valve are respectively connected with a first port and a second port of the bidirectional balance valve, and a third port and a fourth port of the bidirectional balance valve are respectively connected with a load oil cylinder. According to the utility model, the problem of frequent abnormal wear faults of the gear pump caused by lower rotating speed of the gear pump is avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of aerial work platforms, and particularly relates to an aerial work platform and its hydraulic control system. Background Art

[0002] For the hydraulic control system of the existing electric articulated boom aerial work platforms in the short boom section (usually referring to 10 - 16 meters), generally, the connection mode of DC motor + gear pump or AC motor + gear pump is adopted, and the control mode of pump control or valve control, or the combined control mode of pump control and valve control is used to realize the boom movement and steering movement of the whole vehicle.

[0003] When the flow requirements of some pump control actions of the electric articulated boom aerial work platforms in the short boom section are met, the rotational speed of the gear pump is relatively low, basically close to the minimum rotational speed of the gear pump, resulting in frequent abnormal wear failures of the gear pump; while ensuring that the operating speeds of the other actions of the whole machine are not affected, that is, it is particularly important to increase the motor speed without reducing the displacement of the gear pump.

[0004] Taking the hydraulic system of the articulated boom aerial work platform with the model AB14 / 16EJ as an example, when the actual required flow rate Q A for the fly boom movement is 2.6L / min, assuming the displacement D of the main power - gear pump is 4.5ml / r, then the theoretical output flow rate of the hydraulic pump (i.e., the gear pump) during the fly boom movement is:

[0005] Q T = Q A / η (1)

[0006] Wherein, Q T represents the theoretical output flow rate of the hydraulic pump; Q A represents the actual required flow rate for the fly boom movement; η represents the volumetric efficiency, and the volumetric efficiency of the gear pump is generally taken as 92%. According to formula (1), the theoretical output flow rate of the hydraulic pump can be calculated as 2.83L / min. The relationship between the theoretical output flow rate of the hydraulic pump and its rotational speed is:

[0007] Q T = Dn (2)

[0008] Wherein, D represents the displacement of the gear pump, and n represents the rotational speed of the gear pump. According to formula (2), the rotational speed of the gear pump can be calculated as 629r / min, which is basically close to the minimum rotational speed of the gear pump, 600r / min, and is likely to cause frequent abnormal wear failures of the gear pump. Content of the Utility Model

[0009] The purpose of the utility model is to provide an aerial work platform and its hydraulic control system to solve the problem of frequent abnormal wear failures of the gear pump caused by the relatively low rotational speed of the gear pump.

[0010] The present utility model solves the above technical problems through the following technical solutions: A hydraulic control system for an aerial work platform, comprising a hydraulic oil tank, a drive motor for driving a gear pump, the gear pump, a reversing valve, a two-way balance valve, a unloading valve, and a throttling member; the inlet of the gear pump is connected to the hydraulic oil tank, and the outlet of the gear pump is connected to the first port of the reversing valve and the first port of the unloading valve; the second port of the unloading valve is connected to the throttling member, and the throttling member is connected to the second port of the reversing valve and the hydraulic oil tank; the third port and the fourth port of the reversing valve are respectively connected to the first port and the second port of the two-way balance valve, and the third port and the fourth port of the two-way balance valve are respectively connected to a load cylinder.

[0011] Further, a first filter is provided on the outlet pipeline of the gear pump, and a second filter is provided on the pipeline between the throttling member and the hydraulic oil tank.

[0012] Further, a check valve is provided on the outlet pipeline of the gear pump.

[0013] Further, a relief valve is connected in parallel at both ends of the unloading valve and the throttling member.

[0014] Further, the throttling member is one of a damper, a throttle orifice, and a throttle valve.

[0015] Further, the drive motor is a DC motor or an AC motor.

[0016] Further, the reversing valve is a three-position four-way solenoid reversing valve or a proportional reversing valve.

[0017] Further, the two-way balance valve includes a first damper and a second damper, and the first damper and the second damper are provided between the first port and the second port of the two-way balance valve.

[0018] Based on the same concept, the present utility model also provides an aerial work platform, which includes the above-mentioned hydraulic control system.

[0019] Beneficial effects

[0020] Compared with the prior art, the advantages of the present utility model are as follows:

[0021] The present utility model introduces a balance valve. For actions with a relatively low rotational speed of the gear pump, while not affecting the corresponding action speed, it increases the rotational speed of the gear pump, avoiding the problem of frequent abnormal wear and tear failures of the gear pump caused by the relatively low rotational speed of the gear pump; the system action impact is optimized through the combination of a unloading valve and a throttling member, enhancing the product experience. Brief description of the drawings

[0022] To more clearly illustrate the technical solution of the present utility model, the following will briefly introduce the drawings required for description in the embodiments. Obviously, the drawings in the following description are only one embodiment of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0023] Figure 1 It is a schematic diagram of the hydraulic control system of the aerial work platform in the embodiment of the present utility model.

[0024] Explanation of reference numerals: 1 - hydraulic oil tank, 2 - drive motor, 3 - gear pump, 4 - check valve, 5 - first filter, 6 - relief valve, 7 - unloading valve, 8 - directional valve, 9 - two-way balance valve, 10 - load cylinder, 11 - damper, 12 - second filter. Specific embodiments

[0025] The following will clearly and completely describe the technical solutions in the present utility model in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present utility model.

[0026] The following will detail the technical solutions of the present application with specific embodiments. These several specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0027] As Figure 1 shown, a hydraulic control system of an aerial work platform provided by an embodiment of the present utility model includes a hydraulic oil tank 1, a drive motor 2 for driving a gear pump 3, a gear pump 3, a directional valve 8, a two-way balance valve 9, an unloading valve 7, and a throttling member; the inlet of the gear pump 3 is connected to the hydraulic oil tank 1, and the outlet of the gear pump 3 is connected to the first port of the directional valve 8 and the first port of the unloading valve 7; the second port of the unloading valve 7 is connected to the throttling member, and the throttling member is connected to the second port of the directional valve 8 and the hydraulic oil tank 1; the third port of the directional valve 8 is connected to the first port of the two-way balance valve 9, the fourth port of the directional valve 8 is connected to the second port of the two-way balance valve 9, and the third port and the fourth port of the two-way balance valve 9 are respectively connected to the load cylinder 10.

[0028] Take the flying boom movement as an example. According to formula (2), it can be known that when the displacement of the gear pump 3 remains unchanged, the rotational speed of the gear pump 3 increases during the flying boom movement, and the output flow rate of the gear pump 3 will increase synchronously. Due to the introduction of the two-way balance valve 9, the outlet flow rate of the gear pump 3 is divided into two parts: one part passes through the first port and the third port of the reversing valve 8 and the check valve in the two-way balance valve 9 in sequence, reaches the rodless cavity of the load cylinder 10, and pushes the load cylinder 10 to extend to complete the flying boom movement; the other part passes through the first port and the third port of the reversing valve 8, the first port and the second port of the two-way balance valve 9, and then reaches the hydraulic oil tank 1 through the fourth port and the second port of the reversing valve 8. By dividing the flow rate into two parts through the two-way balance valve 9, one part is provided to the load cylinder 10 to complete the flying boom movement, and the other part flows back to the hydraulic oil tank 1 through the pressure dividing bridge formed by the first port, the second port of the two-way balance valve 9 and the pilot oil passage, which increases the outlet flow rate of the gear pump 3, thereby increasing the rotational speed of the gear pump 3, making the rotational speed of the gear pump 3 corresponding to each action in the system within its required range, and avoiding the problem of frequent abnormal wear failures of the gear pump 3 caused by low rotational speed and high friction of the gear pump 3; while increasing the rotational speed of the drive motor 2, it will not affect the flying boom movement speed.

[0029] Since a throttling element is provided after the unloading valve 7, when the action stops and the unloading valve 7 loses power and opens, the outlet pressure of the gear pump 3 will not immediately drop to 0, but the pressure will gradually decrease through the throttling element, and the action speed will gradually slow down, improving the instantaneous impact during the stop action and enhancing the product experience.

[0030] In a specific embodiment of the present utility model, the two-way balance valve 9 includes a first damping and a second damping, and the first damping and the second damping are arranged between the first port and the second port of the two-way balance valve 9. The first damping, the second damping of the two-way balance valve 9 and the pilot oil passage of the two-way balance valve 9 form a pressure dividing bridge, reducing the pilot ratio of the entire two-way balance valve 9.

[0031] The first damping and the second damping in the two-way balance valve 9 can be replaced with dampings of different sizes, such as dampings of 0.5mm, 0.6mm, 0.7mm, etc. By changing the dampings of different sizes, the flow rate of the pressure dividing bypass oil passage of the two-way balance valve 9 is changed to adapt to actions with different speed requirements, such as the swing of the workbench, the rotation of the turntable, the flying boom movement, the walking steering, etc.

[0032] In a specific embodiment of the present utility model, a first filter 5 is provided on the outlet pipeline of the gear pump 3, and a second filter 12 is provided on the pipeline between the throttling element and the hydraulic oil tank 1. The impurities in the oil circuit are filtered out through the first filter 5 and the second filter 12 to protect the normal operation and rotation of the system.

[0033] In a specific embodiment of the present utility model, a check valve 4 is provided on the outlet pipeline of the gear pump 3.

[0034] In a hydraulic system, the check valve 4 and the directional control valve 8 are usually integrated on a main valve body to achieve a connection mode of the gear pump 3 - pipeline - the first filter 5 - pipeline - the check valve 4. After the driving motor 2 stops running, the pressure in the pipeline between the gear pump 3 and the check valve 4 will push the gear pump 3 to rotate in the reverse direction, causing the gear pump 3 to suck air and dry grind. In the present utility model, a check valve 4 is provided at the outlet of the gear pump 3, and the pressure in the pipeline between the gear pump 3 and the check valve 4 cannot push the gear pump 3 to rotate in the reverse direction, avoiding the problem that the high pressure at the outlet of the gear pump 3 reversely pushes the gear pump 3 to rotate when the driving motor 2 stops running, thereby causing problems such as reverse air suction and wear of the gear pump 3, and improving the wear failure of the gear pump 3. At the same time, the check valve 4 also plays a role in stabilizing the system flow rate, preventing the influence of system pressure fluctuations on the gear pump 3, and reducing the vibration and noise of the gear pump 3.

[0035] In a specific embodiment of the present utility model, a relief valve 6 is connected in parallel at both ends of the unloading valve 7 and the throttling element, playing a role in safety protection.

[0036] In a specific embodiment of the present utility model, the throttling element is one of a damper 11, a throttle orifice, and a throttle valve.

[0037] In a specific embodiment of the present utility model, the driving motor 2 is a DC motor or an AC motor.

[0038] In a specific embodiment of the present utility model, the directional control valve 8 is a three-position four-way solenoid directional control valve or a proportional directional control valve.

[0039] The above-disclosed are only specific embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model can easily think of changes or variations, which should all be covered within the protection scope of the present utility model.

Claims

1. A hydraulic control system for an aerial work platform, characterized in that: The hydraulic control system includes a hydraulic oil tank, a drive motor for driving a gear pump, a gear pump, a reversing valve, a two-way balancing valve, an unloading valve and a throttling device; the inlet of the gear pump is connected to the hydraulic oil tank, and the outlet of the gear pump is connected to the first port of the reversing valve and the first port of the unloading valve; the second port of the unloading valve is connected to the throttling device, and the throttling device is connected to the second port of the reversing valve and the hydraulic oil tank; the third port and the fourth port of the reversing valve are respectively connected to the first port and the second port of the two-way balancing valve, and the third port and the fourth port of the two-way balancing valve are respectively connected to the load cylinder.

2. The hydraulic control system of the aerial work platform according to claim 1, characterized in that: A first filter is arranged on the outlet pipeline of the gear pump, and a second filter is arranged on the pipeline between the throttling element and the hydraulic oil tank.

3. The hydraulic control system of the aerial work platform according to claim 1, characterized in that: A one-way valve is arranged on the outlet pipeline of the gear pump.

4. The hydraulic control system of the aerial work platform according to claim 1, characterized in that: An overflow valve is connected in parallel at both ends of the unloading valve and the throttling element.

5. The hydraulic control system of the aerial work platform according to claim 1, characterized in that: The throttling element is one of a damper, a throttle hole and a throttle valve.

6. The hydraulic control system of the aerial work platform according to claim 1, characterized in that: The driving motor is a DC motor or an AC motor.

7. The hydraulic control system for an aerial work platform according to claim 1, characterized in that: The reversing valve is a three-position four-way electromagnetic reversing valve or a proportional reversing valve.

8. The hydraulic control system for an aerial work platform according to any one of claims 1 to 7, characterized in that: The two-way balancing valve comprises a first damper and a second damper, wherein the first damper and the second damper are arranged between a first port and a second port of the two-way balancing valve.

9. An aerial work platform, characterized in that: The aerial work platform comprises a hydraulic control system as claimed in any one of claims 1 to 8.

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