Steering control system of telescopic boom forklift loader

Abstract

The utility model provides a steering control system of a telescopic boom forklift loader, which comprises a steering gear assembly communicated with a hydraulic oil tank through a working pump, and a front axle steering oil cylinder and a rear axle steering oil cylinder which are communicated with the steering gear assembly through a reversing valve assembly, and the steering gear assembly comprises a front axle steering valve and a rear axle steering valve; the front axle steering valve is provided with a first electromagnet and a first locking electromagnet which are used for controlling the valve element to act. The rear axle steering valve is provided with a second electromagnet, a third electromagnet and a second locking electromagnet which are used for controlling the valve element to act. An L port of the steering gear assembly is communicated with a P port of the rear axle steering valve, an R port of the steering gear assembly is communicated with a T port of the front axle steering valve, and the T port of the rear axle steering valve is communicated with a P port of the front axle steering valve. The front axle steering valve and the rear axle steering valve are arranged, and front axle steering, rear axle steering, crab steering and all-wheel steering and multiple steering modes are achieved through valve element position switching and combined use of the two valves.

Description

Technical Field

[0001] This utility model relates to a steering control system for a telescopic boom forklift, belonging to the field of engineering machinery technology. Background Technology

[0002] Telescopic boom forklifts are widely used in construction engineering, warehousing and logistics, as well as agriculture and animal husbandry. They are commonly used for high-rise building material handling (such as steel, precast slabs, and scaffolding), high-altitude installation operations, material transfer in narrow spaces, hay bale stacking, feed handling, high-altitude fruit picking in orchards, and cleaning of livestock sheds, as well as other work that requires transporting materials to higher places.

[0003] To adapt to different work requirements, existing telescopic boom forklifts have been designed and implemented with various steering methods, including conventional front-wheel steering and all-wheel steering and crab steering for special working conditions. However, during operation, especially during the handling and transportation of materials, telescopic boom forklifts need to maintain the stability of the forked materials. However, existing telescopic boom forklifts do not have a separate rear-wheel steering function. Therefore, a more comprehensive steering system is needed to meet the operating conditions of telescopic boom forklifts and improve the stability of the machine when turning. Summary of the Invention

[0004] Purpose of the invention: To address the shortcomings of existing technologies, this invention adds a rear-wheel steering switching mode to the existing steering modes. This steering mode is suitable for adjusting the direction of the machine during material transport. Its main purpose is to minimize the swaying of the chassis when the rear axle adjusts its direction, thereby preventing material from scattering from the forks. This steering mode further enriches the machine's operating conditions and improves steering stability.

[0005] Technical solution: A telescopic boom forklift steering control system includes a steering gear assembly connected to a hydraulic oil tank via a working pump, and a front axle steering cylinder and a rear axle steering cylinder connected to the steering gear assembly via a reversing valve assembly. The steering gear assembly includes a front axle steering valve connected to the front axle steering cylinder and a rear axle steering valve connected to the rear axle steering cylinder.

[0006] The front axle steering valve is a two-position four-way solenoid valve, and is equipped with a first electromagnet for controlling the movement of the valve core and a first locking electromagnet for locking the position of the valve core.

[0007] The rear axle steering valve is a three-position four-way solenoid valve, and is equipped with a second electromagnet, a third electromagnet for controlling the valve core movement, and a second locking electromagnet for locking the valve core position.

[0008] The L port of the steering assembly is connected to the P port of the rear axle steering valve, and the R port is connected to the T port of the front axle steering valve. The T port of the rear axle steering valve is connected to the P port of the front axle steering valve.

[0009] This invention utilizes a front axle steering valve and a rear axle steering valve, switching the valve core positions of the two valves to achieve multiple steering modes, including front axle steering, rear axle steering, crab steering, and all-wheel steering. In practical applications, the appropriate steering mode can be selected according to the working conditions. Especially in cases where telescopic boom forklifts lack rear-wheel steering, rear-wheel steering can be used for material handling, effectively improving the stability of material handling. This also enriches the vehicle's functions, broadens its application range, and increases work efficiency.

[0010] The steering assembly includes a reversing valve that controls the movement of the valve core via the vehicle steering wheel, and a one-way valve located on the main oil inlet line between the reversing valve and the steering assembly and the replenishment line between the hydraulic oil tank. An overflow valve connected in parallel with the one-way valve is provided between the main oil inlet line and the replenishment line.

[0011] The function of the check valve is to prevent a vacuum or instantaneous low pressure in the oil inlet line when the steering wheel turns too fast. By setting a check valve, hydraulic oil can be added when the oil pressure in the main oil inlet line is low, so as to maintain the oil pressure at a normal level. The relief valve is set to protect the oil circuit safety.

[0012] Angle sensors are installed at the hinge points between the front axle and the left and right front wheels, and at the hinge points between the rear axle and the left and right rear wheels. The angle sensors are connected to the machine controller and are used to monitor the wheel angle.

[0013] Angle sensors can monitor wheel angles in real time. In vehicles with multiple steering modes, if the wheel angle does not return to the predetermined range, switching to other steering modes will cause the wheel steering angle to deviate. In severe cases, it will drag the wheel, causing tire wear, affecting driving safety, and compromising the stability of material transportation.

[0014] Beneficial effects: This utility model, by setting a front axle steering valve and a rear axle steering valve, and by switching the valve core positions of the two valves, can achieve front axle steering, rear axle steering, crab steering, and all-wheel steering, providing multiple steering modes. In practical applications, the appropriate steering mode can be selected according to the working conditions. Especially when telescopic boom forklifts lack rear-wheel steering, the rear-wheel steering method can be used for material handling, effectively improving the stability of material handling. The vehicle's functions are also more abundant, its application range is wider, and its work efficiency is higher.

[0015] When selecting a steering mode, the locking solenoid is energized before the working solenoid, which ensures that the valve core can be adjusted smoothly and avoids valve core jamming affecting the switching of steering modes. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a hydraulic schematic diagram of the present invention.

[0018] Figure 2 This is a table showing the energizing sequence of the electromagnets of this utility model, omitting the representations of the first locking electromagnet and the second locking electromagnet. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0021] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0022] like Figure 1 and 2As shown, a telescopic boom forklift steering control system includes a steering gear assembly 3 connected to a hydraulic oil tank 2 via a working pump 1, and a front axle steering cylinder 4 and a rear axle steering cylinder 5 connected to the steering gear assembly 3 via a reversing valve 31 assembly. The steering gear assembly includes a front axle steering valve 6 connected to the front axle steering cylinder 4 and a rear axle steering valve 7 connected to the rear axle steering cylinder 5.

[0023] The front axle steering valve 6 is a two-position four-way solenoid valve, and is equipped with a first solenoid 61 for controlling the valve core movement and a first locking solenoid 62 for locking the valve core position.

[0024] The rear axle steering valve 7 is a three-position four-way solenoid valve, and is equipped with a second electromagnet 71, a third electromagnet 72 for controlling the valve core movement, and a second locking electromagnet 73 for locking the valve core position.

[0025] The L port of the steering assembly 3 is connected to the P port of the rear axle steering valve 7, and the R port is connected to the T port of the front axle steering valve 6. The T port of the rear axle steering valve 7 is connected to the P port of the front axle steering valve 6.

[0026] This invention, by setting a front axle steering valve 6 and a rear axle steering valve 7, allows for the switching of the valve core positions of the two valves, enabling multiple steering modes including front axle steering, rear axle steering, crab steering, and all-wheel steering. In practical applications, the appropriate steering mode can be selected according to the working conditions. Especially in cases where telescopic boom forklifts lack rear-wheel steering, rear-wheel steering can be used for material handling, effectively improving the stability of material handling. This also enriches the vehicle's functions, broadens its application range, and increases work efficiency.

[0027] The steering assembly 3 includes a reversing valve 31 that controls the movement of the valve core via the vehicle steering wheel, and a one-way valve 32 disposed on the main oil inlet line between the reversing valve 31 and the steering assembly and the replenishment line between the hydraulic oil tank 2. An overflow valve 33 is disposed between the main oil inlet line and the replenishment line and is connected in parallel with the one-way valve 32.

[0028] The function of the one-way valve 32 is to prevent the occurrence of vacuum or instantaneous low pressure in the oil inlet line when the steering wheel turns too fast. By setting the one-way valve 32, hydraulic oil can be added when the oil pressure in the main oil inlet line is low, so as to maintain the oil pressure at a normal level. The relief valve 33 is set to protect the oil circuit safety.

[0029] Angle sensors are installed at the hinge points between the front axle and the left and right front wheels, and at the hinge points between the rear axle and the left and right rear wheels. The angle sensors are connected to the machine controller and are used to monitor the wheel angle.

[0030] Angle sensors can monitor wheel angles in real time. In vehicles with multiple steering modes, if the wheel angle does not return to the predetermined range, switching to other steering modes will cause the wheel steering angle to deviate. In severe cases, it will drag the wheel, causing tire wear, affecting driving safety, and compromising the stability of material transportation.

[0031] Includes front-wheel steering mode, crab steering mode, all-wheel steering mode, and rear-wheel steering mode;

[0032] During operation, the correction mode is triggered when the front wheel steering angle X ≥ 1° or the rear wheel steering angle Y ≥ 1°.

[0033] In correction mode, there are two switching logics: enable switching logic and disable switching logic.

[0034] The specific logic for allowing switching is as follows:

[0035] Switch from crab steering mode to front wheel steering mode or rear wheel steering mode;

[0036] Switch from all-wheel steering mode to front-wheel steering mode or rear-wheel steering mode;

[0037] Switch from front-wheel steering mode to rear-wheel steering mode;

[0038] Switch from rear-wheel steering mode to front-wheel steering mode;

[0039] The specific logic for disabling switching is as follows:

[0040] When the driver operates the control panel to switch from crab steering mode to all-wheel steering mode, or from all-wheel steering mode to crab steering mode, or from front wheel steering mode to crab steering mode, or from front wheel steering mode to all-wheel steering mode, or from rear wheel steering mode to crab steering mode, or from rear wheel steering mode to all-wheel steering mode, an alarm is issued, the display screen prompts for correction, and the system is reset to the steering mode the vehicle was in before the switch.

[0041] The specific front wheel steering mode is as follows:

[0042] When the machine is switched to front wheel steering mode, the hydraulic oil is distributed to the steering system through the steering gear assembly 3, and the first electromagnet 61, the second electromagnet 71, the third electromagnet 72, the first locking electromagnet 62 and the second locking electromagnet 73 of the front axle steering valve 6 and the rear axle steering valve 7 are all in a de-energized state.

[0043] When the steering wheel is operated to turn right, hydraulic oil is output from port R of the steering assembly 3, and transported through the pipeline to port T of the front axle steering valve 6. After passing through the front axle steering valve 6, it is output from port B of the front axle steering valve 6, and transported through the pipeline to port V1 of the front axle steering cylinder 4, and the front axle steering cylinder 4 is activated.

[0044] Hydraulic oil is transported from port V2 of the front axle steering cylinder 4 back to port A of the front axle steering valve 6 through a pipeline. At this time, hydraulic oil is transported from port P of the front axle steering valve 6 to port T of the rear axle steering valve 7 through a pipeline. Port P and port T of the rear axle steering valve 7 are connected. Hydraulic oil is then connected from port P of the rear axle steering valve 7 to port L of the steering assembly 3 through a pipeline to complete the right turn.

[0045] The oil flow direction is opposite to that of the right turn.

[0046] The crab-like turning mode is specifically as follows:

[0047] When the machine is switched to crab steering mode, the hydraulic oil is distributed to the steering system through the steering gear assembly 3. The first electromagnet 61 and the first locking electromagnet 62 of the front axle steering valve 6 and the second electromagnet 71 of the rear axle steering valve 7 are de-energized, while the third electromagnet 72 and the second locking electromagnet 73 of the rear axle steering valve 7 are energized.

[0048] When the steering wheel is operated to turn right, hydraulic oil is output from port R of the steering assembly 3, and transported through the pipeline to port T of the front axle steering valve 6. After passing through the front axle steering valve 6, it is output from port B of the front axle steering valve 6, and transported through the pipeline to port V1 of the front axle steering cylinder 4, and the front axle steering cylinder 4 is activated.

[0049] Hydraulic oil is transported from port V2 of the front axle steering cylinder 4 back to port A of the front axle steering valve 6 through a pipeline. At this time, hydraulic oil is transported from port P of the front axle steering valve 6 to port T of the rear axle steering valve 7 through a pipeline. Port T of the rear axle steering valve 7 is connected to port B, and port P is connected to port A. Hydraulic oil is connected to port V2 of the rear axle steering cylinder 5 through a pipeline, and the rear axle steering cylinder 5 is activated.

[0050] Hydraulic oil is transported from port V1 of the rear axle steering cylinder 5 back to port A of the rear axle steering valve 7 through a pipeline. Port P inside the rear axle steering valve 7 is connected to port A. Hydraulic oil is then connected from port P of the rear axle steering valve 7 to port L of the steering assembly 3 through a pipeline to complete the right turn.

[0051] The oil flow direction is opposite to that of the right turn.

[0052] The all-wheel steering mode is specifically as follows:

[0053] When the machine is switched to all-wheel steering mode, the hydraulic oil is distributed to the steering system through the steering gear assembly 3. The first electromagnet 61 and the first locking electromagnet 62 of the front axle steering valve 6 and the third electromagnet 72 of the rear axle steering valve 7 are de-energized, while the second electromagnet 71 and the second locking electromagnet 73 of the rear axle steering valve 7 are energized.

[0054] When the steering wheel is operated to turn right, hydraulic oil is output from port R of the steering assembly 3, and transported through the pipeline to port T of the front axle steering valve 6. After passing through the front axle steering valve 6, it is output from port B of the front axle steering valve 6, and transported through the pipeline to port V1 of the front axle steering cylinder 4, and the front axle steering cylinder 4 is activated.

[0055] Hydraulic oil is transported from port V2 of the front axle steering cylinder 4 back to port A of the front axle steering valve 6 through a pipeline. At this time, hydraulic oil is transported from port P of the front axle steering valve 6 to port T of the rear axle steering valve 7 through a pipeline. Port T of the rear axle steering valve 7 is connected to port A, and port P is connected to port B. Hydraulic oil is connected to port V1 of the rear axle steering cylinder 5 through a pipeline, and the rear axle steering cylinder 5 is activated.

[0056] Hydraulic oil is transported from port V2 of the rear axle steering cylinder 5 back to port B of the rear axle steering valve 7 through a pipeline. Port P and port B in the rear axle steering valve 7 are connected. Hydraulic oil is then connected from port P of the rear axle steering valve 7 to port L of the steering assembly 3 through a pipeline to complete the right turn.

[0057] The oil flow direction is opposite to that of the right turn.

[0058] The rear-wheel steering mode is specifically as follows:

[0059] When the machine is switched to rear wheel steering mode, the hydraulic oil is distributed to the steering system through the steering gear assembly 3. The first electromagnet 61 and the first locking electromagnet 62 of the front axle steering valve 6, the second electromagnet 71 and the second locking solenoid valve of the rear axle steering valve 7 are all energized, and the third electromagnet 72 is de-energized.

[0060] When the steering wheel is turned to the right, the oil is supplied through the pipeline to port T of the front axle steering valve 6. Ports T and P of the front axle steering valve 6 are connected. The oil is then supplied through the pipeline to port T of the rear axle steering valve 7. At this time, the oil passage inside the rear axle steering valve 7 is connected to port T and port A, and port P and port B. The hydraulic oil is connected through the pipeline to port V1 of the rear axle steering cylinder 5, and the rear axle steering cylinder 5 is activated.

[0061] Hydraulic oil is transported from port V2 of the rear axle steering cylinder 5 back to port B of the front axle steering valve 6 through a pipeline. The internal port P of the rear axle steering valve 7 is connected to port B. Hydraulic oil is then connected from port P of the rear axle steering valve 7 to port L of the steering assembly 3 through a pipeline to complete the right turn.

[0062] The oil flow direction is opposite to that of the right turn.

[0063] In the initial steering mode selection,

[0064] When the front wheel steering mode is selected, the first locking electromagnet 62 and the second locking electromagnet 73 are not energized.

[0065] When the crab steering mode is selected, the second locking electromagnet 73 is energized first, and t milliseconds later, the third electromagnet 72 is energized; after T seconds, the second locking electromagnet 73 is de-energized, and t milliseconds later, the third electromagnet 72 is de-energized.

[0066] When all-wheel steering mode is selected, the second locking electromagnet 73 is energized first, and t milliseconds later, the second electromagnet 71 is energized; after T seconds, the second locking electromagnet 73 is de-energized, and t milliseconds later, the second electromagnet 71 is de-energized.

[0067] When the rear wheel steering mode is selected, the first locking electromagnet 62 and the second locking electromagnet 73 are energized first. After t milliseconds, the first electromagnet 61 and the second electromagnet 71 are energized. After T seconds, the first locking electromagnet 62 and the second locking electromagnet 73 are de-energized. After t milliseconds, the first electromagnet 61 and the second electromagnet 71 are de-energized.

[0068] Where t ranges from 100 to 500, and T ranges from 1 to 3.

[0069] In this embodiment, t is 200 and T is 2.

[0070] During the switching of steering modes, the switching conditions must be met, namely X < 1° and Y < 1°.

[0071] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0072] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A telescopic handler steering control system, comprising a steering gear assembly (3) communicated with a hydraulic oil tank (2) through a working pump (1), and a front axle steering oil cylinder (4) and a rear axle steering oil cylinder (5) communicated with the steering gear assembly (3) through a reversing valve (31) assembly, characterized in that: The steering assembly includes a front axle steering valve (6) connected to the front axle steering cylinder (4) and a rear axle steering valve (7) connected to the rear axle steering cylinder (5). The front axle steering valve (6) is a two-position four-way solenoid valve, and is equipped with a first electromagnet (61) for controlling the valve core movement and a first locking electromagnet (62) for locking the valve core position. The rear axle steering valve (7) is a three-position four-way solenoid valve, and is equipped with a second electromagnet (71) and a third electromagnet (72) for controlling the valve core movement, and a second locking electromagnet (73) for locking the valve core position. The L port of the steering assembly (3) is connected to the P port of the rear axle steering valve (7), and the R port is connected to the T port of the front axle steering valve (6). The T port of the rear axle steering valve (7) is connected to the P port of the front axle steering valve (6).

2. The reach truck steering control system of claim 1, wherein: The steering assembly (3) includes a reversing valve (31) that controls the movement of the valve core via the vehicle steering wheel, and a check valve (32) disposed on the main oil inlet line between the reversing valve (31) and the steering assembly and the replenishment line between the hydraulic oil tank (2). An overflow valve (33) is disposed between the main oil inlet line and the replenishment line and is connected in parallel with the check valve (32).

3. The reach truck steering control system of claim 1, wherein: Angle sensors are installed at the hinge points between the front axle and the left and right front wheels, and at the hinge points between the rear axle and the left and right rear wheels. The angle sensors are connected to the machine controller and are used to monitor the wheel angle.

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