Forklift cab posture control system
By using a hydraulically driven lifting device and piston accumulator, the problem of unstable cab posture of heavy forklifts on complex road surfaces is solved, achieving smooth lifting and shock absorption of the cab, and improving the driver's visibility and safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ANHUI HELI CO LTD
- Filing Date
- 2025-06-23
- Publication Date
- 2026-07-31
AI Technical Summary
When heavy forklifts travel on complex road surfaces, the cab posture is unstable, which leads to obstructed driver visibility and unsafe driving. Existing shock absorption devices are not effective.
The system employs a hydraulically driven lifting device and piston accumulator, controlling the cab's posture through front and rear lifting cylinder groups. Combined with position and pressure sensors, it achieves automatic adjustment, improving the cab's stability and shock absorption.
It improves the driver's visibility, enhances driving safety, and achieves better shock absorption through automatic adjustment of the hydraulic system, thus improving driving comfort.
Smart Images
Figure CN224577969U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of forklift technology, specifically to a heavy-duty forklift cab posture control system. Background Technology
[0002] Heavy-duty forklifts, due to their large weight, are equipped with solid tires. They also typically employ rigid suspension systems, achieving load stability through fixed axle devices and rigid tire support. The cab is mounted on the frame. Solid tires lack cushioning, resulting in poor overall shock absorption, especially noticeable on complex road surfaces such as slopes and bumpy roads. To improve driving comfort, shock-absorbing seats and shock-absorbing devices (such as rubber pads and air springs) are commonly used, but their effectiveness varies depending on road conditions. Because the cab on heavy-duty forklifts is usually fixed at a fixed height, the cab's posture is identical to the slope when driving on inclines, causing discomfort for the driver on steep inclines. Furthermore, when driving uphill, the cab tilts backward, severely obstructing the driver's view and creating safety hazards. Utility Model Content
[0003] To address the aforementioned problems, this utility model provides a forklift cab posture control system and control method.
[0004] The specific technical solution is as follows:
[0005] A forklift cab posture control system includes a cab with a lifting device installed at the bottom. The lifting device includes a front lifting cylinder assembly and a rear lifting cylinder assembly. The oil inlets of both the front and rear lifting cylinder assemblies are connected to a control valve via a distribution valve. The oil inlet of the control valve is connected to an oil tank via a hydraulic pump. The oil return ports of both the front and rear lifting cylinder assemblies are connected to the oil tank.
[0006] The oil inlets of both the front and rear lifting cylinder assemblies are connected to the piston accumulator via damped shuttle valves for shock absorption.
[0007] In a further embodiment, the front lifting cylinder assembly includes front cylinder one and front cylinder two, which are respectively installed at the bottom of the front side of the cab, for controlling the height of the front side of the cab; the rear lifting cylinder assembly includes rear cylinder one and rear cylinder two, which are respectively installed at the bottom of the rear side of the cab, for controlling the height of the rear side of the cab.
[0008] In a further embodiment, a front diverter valve is connected in series between the distribution valve and the front lifting cylinder assembly, and a rear diverter valve is connected in series between the distribution valve and the rear lifting cylinder assembly.
[0009] In a further embodiment, a front variable damping throttle valve is connected between the front lifting cylinder assembly and the oil tank, and a rear variable damping throttle valve is connected between the rear lifting cylinder assembly and the oil tank.
[0010] In a further embodiment, position sensors and pressure sensors are installed on each of the front cylinder 1, front cylinder 2, rear cylinder 1, and rear cylinder 2; the signal terminals of the position sensors, pressure sensors, control valves, and distribution valves are all electrically connected to the controller.
[0011] In a further embodiment, the hydraulic pump is electrically connected to a motor for driving, and an overflow valve is connected to the oil outlet of the hydraulic pump.
[0012] This application utilizes a piston accumulator to store or compensate hydraulic oil in the front and rear lifting cylinder assemblies, thereby achieving vibration damping in the cab. Compared to existing vibration damping devices such as shock-absorbing seats and rubber pads with rigid connections, this application achieves better vibration damping through an oil circuit, significantly improving driving comfort. Furthermore, the piston accumulator can adaptively dampen vibrations according to the magnitude of the vibration.
[0013] In this application, the cab is raised as a whole via a lifting device, improving the driver's field of vision and adapting to high-visibility operating scenarios. Furthermore, this application allows for separate control of the lifting height of the front and rear lifting cylinder assemblies, preventing the front of the cab from tilting upwards and obstructing the driver's view. This ensures that when the vehicle is traveling uphill on a slope, the cab remains level relative to the ground, expanding the driver's field of vision and allowing them to observe the position of the fork tips, thus improving operational safety. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the structure of this utility model;
[0015] Figure 2 This is a schematic diagram of the original horizontal state of the driver's cab of this utility model;
[0016] Figure 3 This is a schematic diagram of the horizontal state of the driver's cab of this utility model when it is raised to its maximum height.
[0017] Figure 4 This is a schematic diagram of the original state of the cab when the cab of this utility model is going uphill;
[0018] Figure 5 This is a schematic diagram showing the cab of this utility model after it has been kept level when going uphill.
[0019] Figure 6 This is a schematic diagram showing the adjustment of the driver's cab when going uphill according to this utility model;
[0020] Figure 7This is a schematic diagram of the hydraulic system of this utility model.
[0021] In the diagram: 1-oil tank, 2-motor, 3-hydraulic pump, 4-relief valve, 5-control valve, 6-distribution valve, 7-piston accumulator, 8-damped shuttle valve, 9-rear diverter valve, 10-front diverter valve, 11-rear cylinder one, 12-rear cylinder two, 13-rear variable damping throttle valve, 14-controller, 15-front variable damping throttle valve, 16-front cylinder one, 17-front cylinder two; C1, C2, C3, and C4 are position sensors.
[0022] 100 - Lifting device; 200 - Driver's cab;
[0023] In the diagram, the dashed lines represent electrical circuits, and the solid lines represent oil circuits. Detailed Implementation
[0024] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.
[0025] The lifting cylinder, distribution valve, flow divider valve, control valve, hydraulic pump, damped shuttle valve, piston accumulator, variable damping throttle valve, relief valve, etc. used in this application are all commonly used known components in hydraulic systems.
[0026] In this context, the control valve controls the fluid pressure, flow rate, or direction by adjusting the position of the valve core, thereby controlling the actuator (such as a hydraulic cylinder). For example, the HydraForce RV10-22 model can be applied to this application.
[0027] A distribution valve is a device used to control the distribution of fluid among multiple outlets. It can adjust the flow rate of each outlet as needed to ensure that the fluid is distributed to different locations in a predetermined proportion or sequence. For example, the HydraForce SV10-P22A model can be applied to this application.
[0028] A flow divider valve is a device used to divert fluid from a single inlet to multiple outlets, distributing the fluid to each outlet according to a fixed ratio or method. Even when the same oil source supplies the same flow rate to two or more actuators in a hydraulic system (equal flow division), or supplies flow rate to two actuators in a certain proportion (proportional flow division), the speeds of the two actuators are kept synchronized or in a constant ratio. For example, the CSAB shuttle valve from SUN Hydraulics can be applied to this application.
[0029] A piston accumulator is a high-pressure piston-type accumulator consisting of a piston, cylinder, and seals between them. It uses the piston to separate gas and liquid into two chambers, storing or releasing hydraulic energy through the compression and expansion of the gas (usually nitrogen). When the system pressure increases, the hydraulic oil pushes the piston to compress the gas and store energy; when the system pressure decreases, the gas expands and pushes the piston to release the hydraulic oil to replenish the system's needs. Examples include the German Bolenz Schafer piston accumulator KAK 0.5-375-06, and those distributed by Suzhou Dragoo Hydraulic Technology Co., Ltd. EHP series Piston accumulators can all be used in this application.
[0030] A variable damping throttle valve regulates flow rate by adjusting the valve's diameter, pipe angle, and other parameters to control the fluid's flow velocity. The HAWE Q-type damping throttle valve is a suitable option.
[0031] The damped shuttle valve uses the oil pressure difference between the two ends of the valve core to dynamically and adaptively open the valve core in real time and make it reciprocate. The displacement of the valve core switches between two flow channels to achieve fluid switching and throttling control. For example, the CSAB type shuttle valve from SUN Hydraulics can be applied to this application.
[0032] A tilt sensor is an electronic device that measures the change in angle between an object and a horizontal or vertical plane, detecting the degree of tilt of the object in a certain direction. It typically utilizes the principle of gravity sensing, measuring the change in acceleration caused by gravity through an internal accelerometer or gyroscope, and then calculating the tilt angle of the object. In this application, a tilt sensor is used to detect whether the vehicle frame tilts forward or backward by one angle when traveling on a slope.
[0033] The controller in this application is also a product known in the art, such as the Parker MC43FS.
[0034] This embodiment provides a forklift cab posture control system, including a cab 200, such as... Figure 1As shown, a lifting device 100 is installed at the bottom of the cab 200, which drives the cab to rise and fall, thereby raising the cab on slopes, expanding the driver's field of vision, and improving driving safety. The lifting device includes a front lifting cylinder assembly and a rear lifting cylinder assembly. The front lifting cylinder assembly is located at the front of the cab's bottom end, controlling the height of the front side of the cab; the rear lifting cylinder assembly is located at the rear of the cab's bottom end, controlling the height of one side of the cab. The oil inlets of both the front and rear lifting cylinder assemblies are connected to a control valve 5 via a distribution valve 6. The oil inlet of the control valve 5 is connected to the oil tank 1 via a hydraulic pump 3. The oil return ports of both the front and rear lifting cylinder assemblies are connected to the oil tank 1, forming a hydraulic circuit. The hydraulic pump 3 introduces hydraulic oil from the oil tank 1 into the control valve 5, and the control valve 5 introduces hydraulic oil into two oil circuits in the distribution valve 6, and then into the oil inlets of the front and rear lifting cylinder assemblies (e.g., [missing information]). Figure 7 As shown), the front and rear lifting cylinder assemblies work to raise the cab.
[0035] The hydraulic pump 3 is driven by a motor 2, and the oil outlet of the hydraulic pump 3 is connected to an overflow valve 4.
[0036] The oil inlets of both the front and rear lifting cylinder assemblies are connected to the piston accumulator 7 via damping shuttle valves 8 for shock absorption.
[0037] When the vehicle travels on uneven roads, the cab experiences bumps, causing changes in the hydraulic pressure in the front and rear lifting cylinder assemblies. Specifically, when the hydraulic pressure in one of the front or rear lifting cylinder assemblies increases, the hydraulic oil enters the piston accumulator 7 for storage; when the hydraulic pressure decreases, the hydraulic oil in the piston accumulator 7 replenishes it. This controls the flatness of the cab, thus achieving shock absorption and improving driving comfort.
[0038] To ensure smoother lifting of the cab, the front lifting cylinder assembly includes front cylinder 16 and front cylinder 17, respectively installed at the bottom front side of the cab 200, for controlling the height of the front side of the cab; the rear lifting cylinder assembly includes rear cylinder 11 and rear cylinder 12, respectively installed at the bottom rear side of the cab 200, for controlling the height of the rear side of the cab. Figure 1 As shown, front cylinder 16, front cylinder 27, rear cylinder 11, and rear cylinder 212 are located at the four corners of the bottom end face of the cab.
[0039] like Figure 7 As shown, a front diverter valve 10 is connected in series between the distribution valve 6 and the front lifting cylinder assembly. The front diverter valve 10 diverts hydraulic oil equally or proportionally to the front cylinder 16 and the front cylinder 2 17. A rear diverter valve 9 is connected in series between the distribution valve 6 and the rear lifting cylinder assembly. The rear diverter valve 9 diverts hydraulic oil equally or proportionally to the rear cylinder 11 and the rear cylinder 2 12.
[0040] A front variable damping throttle valve 15 is connected between the front lifting cylinder assembly and the oil tank 1, and a rear variable damping throttle valve 13 is connected between the rear lifting cylinder assembly and the oil tank 1. The front and rear variable damping throttle valves can control the flow rate and velocity of the return oil, thereby controlling the descent speed of the front and rear lifting cylinder assemblies and improving their stability.
[0041] In order to accurately control the movement of each hydraulic cylinder, position sensors and pressure sensors are installed on the front hydraulic cylinder 16, the front hydraulic cylinder 27, the rear hydraulic cylinder 11, and the rear hydraulic cylinder 22. The position sensors are installed at the piston rod end of each hydraulic cylinder (i.e., the connection point with the cab) to detect the stroke of the hydraulic cylinder. The pressure sensors are installed inside each hydraulic cylinder to detect the hydraulic pressure.
[0042] The signal terminals of the position sensor, pressure sensor, control valve 5, and distribution valve 6 are all electrically connected to the controller 14. That is, the position sensor and pressure sensor transmit the detection signals to the controller, which processes them and then sends control signals to control valve 5 and distribution valve 6, thereby controlling the oil output of the two oil outlets of control valve 5 and distribution valve 6 respectively, and thus controlling the lifting height of each cylinder respectively.
[0043] The specific work process is as follows:
[0044] Motor 2 drives hydraulic pump 3 to work, delivering hydraulic oil to the inlet A of control valve 5. The inlet D of relief valve 4 is connected to the outlet of hydraulic pump, and its outlet E is connected to oil tank 1, ensuring that the pressure value of the supply system is controlled at the required 145 Bar. Control valve 5 supplies oil to two oil supply circuits, namely, the outlets B and C of control valve 5 supply oil to the inlets F and G of distribution valve 6, respectively. One of the circuits passes through the inlet F and outlet H of distribution valve 6 and enters the inlet Q of front diverter valve 10, which then splits into two circuits, entering the inlets Y1 of front cylinder 16 and Y4 of front cylinder 17, respectively, through their outlets R and S, driving front cylinder 16 and front cylinder 17 to lift synchronously. During descent, the oil outlet Y2 of front cylinder 16 and the oil outlet Y3 of front cylinder 2 are both connected to the oil inlet K4 of front variable damping throttle valve 15, and the oil outlet K5 of front variable damping throttle valve 15 is connected to oil tank 1 to achieve oil return.
[0045] Meanwhile, when the front cylinder 16 and the front cylinder 2 17 are lifting or falling, the front variable damping throttle valve 15 operates passively to ensure that the front cylinder 16 and the front cylinder 2 17 have a certain back pressure during the oil return or replenishment process. The back pressure is controlled at 55 Bar to smoothly control the operation of the cylinders.
[0046] Simultaneously, another path from control valve 5 enters the inlet N of the rear diversion valve 9 via the inlet G and outlet J of the distribution valve 6, and then splits into two paths, entering the inlet Y7 of rear cylinder 11 and the inlet Y6 of rear cylinder 2 12 via their outlets P and O respectively, driving rear cylinder 11 and rear cylinder 2 12 to lift synchronously. During descent, the outlet Y8 of rear cylinder 11 and the outlet Y5 of rear cylinder 2 12 are both connected to the inlet K2 of the rear variable damping throttle valve 13, and the outlet K1 of the rear variable damping throttle valve 13 is connected to the oil tank 1 to achieve oil return.
[0047] When the rear cylinder 11 and the rear cylinder 212 are raised or lowered, the rear variable damping throttle valve 13 operates passively to ensure that the rear cylinder 11 and the rear cylinder 212 have a certain back pressure during the oil return or oil replenishment process. The back pressure is controlled at 55 Bar to smoothly control the operation of the cylinder.
[0048] Position sensors C1, C2, C3, and C4 detect the stroke of the front cylinder 16, front cylinder 27, rear cylinder 11, and rear cylinder 22 in real time and feed it back to the controller 14. The controller 14 controls the position of the valve core in the control valve 5 and the distribution valve 6 in real time according to the cylinder stroke, thereby controlling the oil distribution in the oil circuit and achieving precise oil supply to each cylinder.
[0049] When it is necessary to raise the cab to improve driving visibility and thus better observe the working conditions of the shovel being lifted, the switch of motor 2 is turned on, causing hydraulic pump 3 to work. Hydraulic oil, after passing through control valve 5 and distribution valve 6, enters the front lifting cylinder group and the rear lifting cylinder group respectively, driving the cab 200 to rise horizontally; if the cab is raised from... Figure 2 The original position shown was raised to, as Figure 3 The highest position shown.
[0050] When the vehicle is on a slope, the strokes of all four cylinders are the same, such as... Figure 4 As shown, the cab is aligned with the ramp, but tilted relative to the horizontal ground; that is, the front of the cab tilts upwards, obstructing the driver's view. Then, the rear lifting cylinder assembly is driven to raise the cab to a greater height than the front lifting cylinder assembly, thus ensuring the cab is level with respect to the horizontal ground (e.g., ...). Figure 5 As shown in the image, this improves the driver's field of vision. Figure 6 The diagram shows the adjustment process.
[0051] When the vehicle travels on uneven roads, the cab experiences bumps, causing changes in the hydraulic pressure in the front and rear lifting cylinder assemblies. Specifically, when the hydraulic pressure in one of the front or rear lifting cylinder assemblies increases, the hydraulic oil enters the piston accumulator 7 for storage; when the hydraulic pressure decreases, the hydraulic oil in the piston accumulator 7 replenishes it. This controls the flatness of the cab, thus achieving shock absorption and improving driving comfort.
[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.
Claims
1. A forklift cab posture control system comprising a cab (200), characterized by: A lifting device (100) is installed at the bottom of the cab (200). The lifting device includes a front lifting cylinder group and a rear lifting cylinder group. The oil inlets of the front lifting cylinder group and the rear lifting cylinder group are connected to the control valve (5) through a distribution valve (6). The oil inlet of the control valve (5) is connected to the oil tank (1) through a hydraulic pump (3). The oil return ports of the front lifting cylinder group and the rear lifting cylinder group are connected to the oil tank (1). The oil inlets of the front lifting cylinder group and the rear lifting cylinder group are connected to the piston accumulator (7) through a damping shuttle valve (8) for shock absorption.
2. A forklift cab posture control system according to claim 1, characterized in that: The front lifting cylinder assembly includes front cylinder one (16) and front cylinder two (17) respectively installed at the bottom front side of the cab (200) for controlling the height of the front side of the cab; the rear lifting cylinder assembly includes rear cylinder one (11) and rear cylinder two (12) respectively installed at the bottom rear side of the cab (200) for controlling the height of the rear side of the cab.
3. The forklift cab posture control system of claim 1, wherein: A front diverter valve (10) is connected in series between the distribution valve (6) and the front lifting cylinder group, and a rear diverter valve (9) is connected in series between the distribution valve (6) and the rear lifting cylinder group.
4. The forklift cab posture control system of claim 1, wherein: A front variable damping throttle valve (15) is connected between the front lifting cylinder assembly and the oil tank (1), and a rear variable damping throttle valve (13) is connected between the rear lifting cylinder assembly and the oil tank (1).
5. A forklift cab posture control system according to claim 2, characterized by: Position sensors and pressure sensors are installed on the front cylinder 1 (16), front cylinder 2 (17), rear cylinder 1 (11), and rear cylinder 2 (12); the signal terminals of the position sensors, pressure sensors, control valve (5), and distribution valve (6) are all electrically connected to the controller (14).
6. A forklift cab posture control system according to claim 1, characterized by: The hydraulic pump (3) is electrically connected to a motor (2) for driving, and the oil outlet of the hydraulic pump (3) is connected to an overflow valve (4).