A hydraulic steering device and a hydraulic steering system for all-terrain vehicles

Abstract

This invention discloses a hydraulic steering device and an all-terrain vehicle hydraulic steering system. The steering gear 6 of the hydraulic steering device adjusts its displacement via a variable displacement control cylinder 9, which is controlled by an electro-proportional two-position three-way directional valve 11. The opening of the oil circuit within the electro-proportional two-position three-way directional valve 11 is controlled by an electrical signal converted from vehicle speed. When the vehicle speed increases, the displacement of the steering gear 6 decreases; when the vehicle speed decreases, the displacement of the steering gear 6 increases. The outlet of the variable displacement pump 1 is connected to a steering oil circuit switching valve 7 via a one-way valve 4. The steering oil circuit switching valve 7 connects the steering gear 6 and the steering cylinder 3. This invention addresses the problem of easy rollover and fishtailing in hydraulically driven all-terrain vehicles at high speeds by providing a hydraulic steering control system that links vehicle speed and steering wheel angle control, adjusting the control ratio of steering wheel angle and overall vehicle angle according to vehicle speed.

Description

Technical Field

[0001] This invention relates to a hydraulic steering control system for an all-terrain vehicle. Background Technology

[0002] Currently, almost all vehicles using hydraulic steering employ hydraulic steering gears to precisely control the steering angle. These hydraulic steering gears are primarily based on a fixed displacement, meaning the steering wheel angle is directly proportional (a constant ratio) to the overall vehicle steering angle. The advantage of this control method is high steering precision, but it also has drawbacks. Regardless of the vehicle's speed, the steering angle is perfectly matched to and fixed with the steering wheel angle. This is very user-friendly at low speeds, but at higher speeds, rapid steering wheel movements can result in dangerous consequences such as rollovers or fishtailing.

[0003] Currently, in the passenger car sector, many intelligent new technologies have been used to assist steering, ensuring high stability and safety in steering control at both low and high speeds. However, in the field of engineering vehicles that use hydraulic steering, the guarantee still relies on the skill of human operators.

[0004] Currently, all-terrain vehicles used in China for emergency rescue, border patrol, and high-altitude material transportation are being used more and more widely due to their good driving performance and excellent all-terrain capability. These vehicles mainly use hydraulic steering, which obviously has the aforementioned disadvantages. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the issue that hydraulically driven all-terrain vehicles are prone to rollover and fishtailing when steering at high speeds. This invention provides a hydraulic steering control system that can link vehicle speed and steering wheel angle control, adjusting the control ratio of steering wheel angle and overall vehicle angle according to vehicle speed.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A hydraulic steering device includes a steering gear 6, the steering gear 6 adjusting the displacement via a steering gear variable displacement control cylinder 9, the steering gear variable displacement control cylinder 9 being controlled by an electro-proportional two-position three-way directional valve 11, the opening of the oil circuit inside the electro-proportional two-position three-way directional valve 11 being controlled by an electrical signal converted from vehicle speed.

[0008] When the vehicle speed increases, the displacement of steering gear 6 decreases; when the vehicle speed decreases, the displacement of steering gear 6 increases.

[0009] A hydraulic steering system for an all-terrain vehicle includes the aforementioned hydraulic steering device. The outlet of the variable pump 1 is connected to the steering oil circuit switching valve 7 via a one-way valve 4. The steering oil circuit switching valve 7 is connected to the steering gear 6 and the steering cylinder 3.

[0010] A branch line at the outlet of check valve 4 is connected to a custom pressure reducing valve 10, which is connected to an electro-proportional two-position three-way directional valve 11.

[0011] There are two steering cylinders 3, which are installed on the articulation device between the front and rear bodies of the all-terrain vehicle. When one steering cylinder 3 retracts, the other steering cylinder 3 extends.

[0012] A safety relief valve 2 is installed in the bypass of the outlet oil circuit of variable pump 1.

[0013] The hydraulic bypass circuits of the steering cylinder 3, which flow into and out of the steering cylinder 3, are simultaneously connected to the buffer / anti-air suction valve combination 8.

[0014] There is a branch line at the outlet of check valve 4 that connects to the return oil line via replenishing check valve 5. Replenishing check valve 5 and check valve 4 are arranged in opposite directions.

[0015] A pressure detection port M is set in the outlet oil circuit of variable pump 1.

[0016] The cylinder bodies of the two steering cylinders 3 are hinged on the articulation device, and the front ends of the two steering cylinders 3 are hinged to the front vehicle body.

[0017] The beneficial effects of this invention are:

[0018] This invention addresses the steering problems inherent in all-terrain vehicles by employing a variable steering ratio hydraulic steering control device that is speed-dependent. This effectively resolves the safe steering behavior of all-terrain vehicles at both high and low speeds, significantly improving vehicle control safety. Furthermore, this hydraulic steering device can also be applied to other hydraulic steering control vehicles and equipment.

[0019] As vehicle speed increases, the displacement of the steering gear decreases; conversely, as vehicle speed decreases, the displacement of the steering gear increases. Through this mechanism, at higher speeds, for the same steering wheel angle, the steering cylinder receives less hydraulic fluid, and its stroke is correspondingly shorter, thus reducing the overall steering angle. At lower speeds, for the same steering wheel angle, the steering cylinder receives more hydraulic fluid, and its stroke is correspondingly longer, thus increasing the overall steering angle. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a hydraulic steering system.

[0021] Figure 2 This is a diagram showing the layout of the steering cylinders. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0023] Example 1:

[0024] A hydraulic steering device includes a steering gear 6. The steering gear 6 has its displacement adjusted by a steering gear variable displacement control cylinder 9. Changing the stroke of the steering gear variable displacement control cylinder 9 adjusts the displacement of the steering gear 6. The steering gear variable displacement control cylinder 9 is controlled by an electro-proportional two-position three-way directional valve 11. The opening of the oil passage within the electro-proportional two-position three-way directional valve 11 is controlled by an electrical signal converted from vehicle speed. Under the control of the electrical signal converted from vehicle speed, the electro-proportional two-position three-way directional valve 11 adjusts the opening of its oil passage. High-pressure hydraulic oil flows through the electro-proportional two-position three-way directional valve 11 into the steering gear variable displacement control cylinder 9, adjusting the steering gear displacement (this step is entirely based on vehicle speed). When the vehicle speed increases, the steering gear 6's displacement decreases; when the vehicle speed decreases, the steering gear 6's displacement increases.

[0025] Example 2:

[0026] like Figure 1 The image shows the hydraulic steering system of the all-terrain vehicle in this embodiment. The hydraulic steering system includes a variable displacement pump 1, a safety relief valve 2, two steering cylinders 3, a one-way valve 4, a replenishing one-way valve 5, a steering gear 6, a steering circuit switching valve 7, a buffer / anti-vacuum valve combination 8, a steering gear variable displacement control cylinder 9, a set value pressure reducing valve 10, an electro-proportional two-position three-way directional valve 11, a hydraulic oil tank 12, and hydraulic circuits, etc.

[0027] The basic circuit for driving the vehicle to steer is as follows: Variable pump 1 draws hydraulic oil from hydraulic oil tank 12. The high-pressure hydraulic oil at the outlet of variable pump 1 opens check valve 4 and flows into steering oil circuit switching valve 7. According to the steering direction of the steering wheel, steering oil circuit switching valve 7 is driven to switch directions. The hydraulic oil flowing into steering oil circuit switching valve 7 flows into steering gear 6. After passing through steering gear 6, it is directly supplied to one chamber of steering cylinder 3. The hydraulic oil in the other chamber of steering cylinder 3 flows through steering oil circuit switching valve 7 for return oil.

[0028] A safety relief valve 2 is installed in the outlet oil circuit of variable pump 1 to ensure the safety of the hydraulic steering system. In addition, a pressure detection port M is installed in the outlet oil circuit of variable pump 1.

[0029] The hydraulic bypass circuits flowing into and out of the steering cylinder 3 are simultaneously connected to the buffer / anti-vacuum valve combination 8 to ensure the safe use of the steering cylinder and prevent cavitation during operation, allowing for rapid oil replenishment.

[0030] The steering gear 6 has a variable displacement, and its displacement adjustment is driven by the steering gear variable control cylinder 9. The displacement of the steering gear 6 can be adjusted by changing the stroke of the steering gear variable control cylinder 9.

[0031] The high-pressure oil at the outlet of check valve 4 flows into the customized pressure reducing valve 10, and then to the electro-proportional two-position three-way directional valve 11. Under the control of the electrical signal after vehicle speed conversion, the opening of the oil circuit inside the electro-proportional two-position three-way directional valve 11 is adjusted. The high-pressure hydraulic oil flows into the steering gear variable displacement control cylinder 9 through the electro-proportional two-position three-way directional valve 11 to adjust the steering gear displacement (this step completes the steering gear displacement adjustment according to vehicle speed). The return port of the electro-proportional two-position three-way directional valve 11 is directly connected to the return oil circuit.

[0032] The return oil circuit is directly connected to the hydraulic oil tank 12, and a bypass oil replenishment check valve 5 is set. Through the oil replenishment check valve 5, oil can be quickly replenished to the steering gear to prevent the steering gear 6 from sucking in air.

[0033] As vehicle speed increases, the displacement of steering gear 6 decreases; conversely, as vehicle speed decreases, the displacement of steering gear increases. Through this method, at higher vehicle speeds, for the same steering wheel angle, the steering cylinder 3 receives less hydraulic fluid, and the stroke of the steering cylinder is correspondingly shorter, thus reducing the overall vehicle steering angle. At lower vehicle speeds, for the same steering wheel angle, the steering cylinder 3 receives more hydraulic fluid, and the stroke of the steering cylinder is correspondingly longer, thus increasing the overall vehicle steering angle.

Claims

1. A hydraulic steering device, comprising a steering gear (6) and a steering cylinder (3), characterized in that: The steering gear (6) adjusts the displacement through the steering gear variable control cylinder (9). The steering gear variable control cylinder (9) is controlled by the electro-proportional two-position three-way directional valve (11). The control ratio of the steering wheel angle and the overall vehicle angle is adjusted according to the vehicle speed. The opening of the oil circuit in the electro-proportional two-position three-way directional valve (11) is controlled by the electrical signal after the vehicle speed is converted. Under the control of the electrical signal after the vehicle speed is converted, the opening of the oil circuit in the electro-proportional two-position three-way directional valve (11) is adjusted. The high-pressure hydraulic oil flows into the steering gear variable control cylinder (9) through the electro-proportional two-position three-way directional valve (11) to adjust the displacement of the steering gear (6). When the vehicle speed increases, the displacement of the steering gear (6) decreases; when the vehicle speed decreases, the displacement of the steering gear (6) increases.

2. A hydraulic steering system for an all-terrain vehicle, comprising the hydraulic steering device as described in claim 1, characterized in that: The outlet of the variable pump (1) is connected to the steering oil circuit switching valve (7) via the check valve (4), and the steering oil circuit switching valve (7) is connected to the steering gear (6) and the steering cylinder (3).

3. The all-terrain vehicle hydraulic steering system according to claim 2, characterized in that: A branch line is connected to a custom pressure reducing valve (10) at the outlet of the check valve (4), and the custom pressure reducing valve (10) is connected to an electro-proportional two-position three-way directional valve (11).

4. The all-terrain vehicle hydraulic steering system according to claim 3, characterized in that: There are two steering cylinders (3), which are installed on the articulation device between the front and rear bodies of the all-terrain vehicle. When one steering cylinder (3) retracts, the other steering cylinder (3) extends.

5. The all-terrain vehicle hydraulic steering system according to claim 4, characterized in that: A safety relief valve (2) is installed in the outlet oil circuit bypass of the variable pump (1).

6. The all-terrain vehicle hydraulic steering system according to claim 4, characterized in that: The hydraulic bypass circuits flowing into and out of the steering cylinder (3) are simultaneously connected to the buffer / anti-air suction valve combination (8).

7. The all-terrain vehicle hydraulic steering system according to claim 4, characterized in that: There is a branch line at the outlet of the check valve (4) that connects to the return oil circuit via the replenishing check valve (5). The replenishing check valve (5) and the check valve (4) are arranged in opposite directions.

8. The all-terrain vehicle hydraulic steering system according to claim 4, characterized in that: A pressure detection port M is set in the outlet oil circuit of the variable pump (1).

9. The all-terrain vehicle hydraulic steering system according to claim 4, characterized in that: The cylinder bodies of the two steering cylinders (3) are hinged on the hinge device, and the front ends of the two steering cylinders (3) are hinged to the front vehicle body.

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