A full active suspension with continuously adjustable stiffness, damping, height

Abstract

The application discloses a full active suspension with continuously adjustable stiffness, damping and height, which comprises a hydraulic cylinder, a gas spring, a stiffness adjusting pipeline and a hydraulic cylinder adjusting pipeline, the stepless adjustment of the suspension stiffness is realized by changing the pressure of the gas spring, the stepless adjustment of the suspension damping is realized by changing the opening of an electromagnetic proportional valve connecting two cavities of the hydraulic cylinder, and the suspension height is changed by changing the oil volume in the two cavities of the hydraulic cylinder through the working of a bidirectional electric oil pump. The application can smoothly adjust the suspension stiffness and damping characteristics according to different loads, speeds and road conditions, the gas spring can effectively absorb high-frequency impacts from the road, and thus the riding comfort and operation stability of the vehicle are improved; and the four-wheel suspension height can be dynamically adjusted, and thus the riding capability of the vehicle under extreme working conditions is improved.

Description

Technical Field

[0001] This invention belongs to the field of vehicle suspension, specifically relating to a fully active suspension with continuously adjustable stiffness, damping, and height. Background Technology

[0002] The suspension system elastically connects the vehicle body and wheels, transmitting all forces and torques between them. During vehicle operation, it continuously dampens and absorbs shocks and vibrations caused by uneven road surfaces, ensuring ride comfort and the integrity of cargo. The suspension system is a crucial component of modern automobiles, significantly impacting ride smoothness and handling stability.

[0003] With technological advancements and rising consumer demands, traditional passive suspension systems are becoming obsolete. Their inability to adjust stiffness and damping cannot adapt to changes in road conditions, vehicle speed, and load, resulting in poor vibration reduction. Advanced active suspension systems are now entering practical applications. These systems dynamically and adaptively adjust the stiffness and damping characteristics of the suspension system based on vehicle motion and road conditions, ensuring the system is always in optimal vibration reduction mode. Furthermore, they can adjust suspension height to improve vehicle passability and safety. Active suspension systems primarily include air suspension and active hydraulic suspension. Air suspension has a slower response and more complex structure, but it effectively absorbs high-frequency vibrations. Active hydraulic suspension responds quickly and allows for precise and rapid adjustments.

[0004] Chinese patent CN202010054263.6 discloses a multi-stage adjustable hydropneumatic suspension and its control method. By connecting multiple external throttle valves and accumulators, and using multiple switching solenoid valves to control the number of throttle valves and accumulators connected to the hydropneumatic suspension, multi-stage adjustable damping and stiffness of the hydropneumatic suspension system can be achieved. However, this suspension system cannot achieve stepless adjustment of the stiffness and damping of the hydropneumatic suspension, nor can it achieve precise adjustment of the suspension height. Furthermore, the use of multiple electronically controlled valves results in insufficient system reliability. Summary of the Invention

[0005] This invention aims to address the shortcomings of existing technologies by providing a fully active suspension and its control method. By controlling the operation of a hydraulic pump and electronically controlled valves, precise and stepless adjustment of the suspension's stiffness, damping, and height is achieved, resulting in superior ride comfort and stability during vehicle operation. Furthermore, three hydraulically controlled valves replace electronically controlled valves to control the oil circuit's on / off state, making height adjustment more reliable and rapid.

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

[0007] The present invention provides a fully active suspension with continuously adjustable stiffness, damping, and height, comprising: a hydraulic cylinder, a gas spring, a stiffness adjustment pipeline, and a hydraulic cylinder adjustment pipeline.

[0008] The hydraulic cylinder is divided into a rod chamber and a rodless chamber by a piston, and the piston rod of the hydraulic cylinder is connected to the unsprung mass.

[0009] The gas spring is divided into an air bladder chamber and an adjustment chamber by a floating piston, and a limiting ring is provided on the inner wall of the adjustment chamber to limit the position of the floating piston in the adjustment chamber; the rigid outer shell of the gas spring is connected to the spring mass component, and the elastic diaphragm at the bottom of the air bladder chamber is connected to the top outer shell of the rodless chamber.

[0010] The stiffness adjustment pipeline is connected to the inlet and outlet of the adjustment cavity respectively, and is used to inject and discharge oil into the adjustment cavity;

[0011] The hydraulic cylinder regulating pipeline is connected to the oil port of the rod chamber and the oil port of the rodless chamber respectively, and is used to inject and discharge oil into them, and realize the flow of oil between the two chambers.

[0012] The fully active suspension described in this invention is also characterized in that the stiffness adjustment pipeline includes: a one-way valve, an electromagnetic proportional valve, an oil pump, and an oil tank.

[0013] The oil inlet of the regulating chamber is connected to the pump port of the oil pump through the one-way valve, the oil suction port of the oil pump is connected to the oil tank, and the oil outlet of the regulating chamber is connected to the oil tank through the electromagnetic proportional valve.

[0014] The hydraulic cylinder regulating pipeline includes: an electromagnetic proportional valve, a normally open hydraulic controlled valve, a first normally closed hydraulic controlled valve, a second normally closed hydraulic controlled valve, a first accumulator, a second accumulator, a first check valve, a second check valve, a third check valve, a fourth check valve, and a bidirectional electric oil pump.

[0015] The first normally closed hydraulic control valve, the bidirectional electric oil pump, and the second normally closed hydraulic control valve are connected in series between the oil port of the rodless chamber and the oil port of the rod chamber.

[0016] A third check valve is connected in parallel to both ends of the pipeline of the first normally closed hydraulic controlled valve, and a fourth check valve is connected in parallel to both ends of the pipeline of the second normally closed hydraulic controlled valve.

[0017] The first accumulator is connected to the pipeline between the oil port of the rodless chamber and the first normally closed hydraulic controlled valve, and the second accumulator is connected to the pipeline between the oil port of the rod chamber and the second normally closed hydraulic controlled valve.

[0018] One end of the electromagnetic proportional valve connected in series with the normally open hydraulic controlled valve is connected to the oil port of the rodless chamber, and the other end is connected to the oil port of the rod chamber.

[0019] One end of the first check valve and the second check valve connected in parallel is connected to the control port of the normally open hydraulic controlled valve, and the other end is connected to both ends of the bidirectional electric oil pump.

[0020] The control port of the first normally closed hydraulic controlled valve is connected in the pipeline between the bidirectional electric oil pump and the second check valve; the control port of the second normally closed hydraulic controlled valve is connected in the pipeline between the bidirectional electric oil pump and the first check valve.

[0021] The working process of the stiffness adjustment pipeline includes:

[0022] The oil pump is controlled to pump oil from the oil tank and inject the oil into the regulating chamber through the one-way valve. The floating piston moves down and compresses the air bladder chamber, thereby increasing the gas pressure in the air bladder chamber and increasing the stiffness of the gas spring.

[0023] The electromagnetic proportional valve is opened, allowing the oil to return from the regulating chamber to the oil tank. The floating piston moves upward, the air bladder expands, reducing the gas pressure in the air bladder and decreasing the stiffness of the gas spring.

[0024] The fully active suspension described in this invention achieves adaptive damping adjustment through the following steps:

[0025] Step 1: Real-time acquisition of the vertical speed of the wheel and the vehicle body, and calculation of the difference between their speeds. If the difference does not exceed the set threshold, the electromagnetic proportional valve maintains its opening unchanged; otherwise, proceed to Step 2.

[0026] Step 2: Determine the direction of the two velocities. If they are in the same direction, open the electromagnetic proportional valve proportionally according to the magnitude of the speed difference. Otherwise, open the electromagnetic proportional valve inversely according to the magnitude of the speed difference.

[0027] The hydraulic cylinder adjustment pipeline adjusts the suspension height through the following process:

[0028] When the bidirectional electric oil pump pumps oil and injects oil into the rodless chamber through the third check valve, the oil reaches the control port of the normally open hydraulic control valve and the second normally closed hydraulic control valve through the pipeline, causing the normally open hydraulic control valve to close and the second normally closed hydraulic control valve to open, thus disabling the damping adjustment. The oil flows back from the rod chamber to the bidirectional electric oil pump, causing the suspension height to rise.

[0029] When the bidirectional electric oil pump pumps oil and injects it into the rod chamber through the fourth check valve, the oil also reaches the control ports of the normally open hydraulic control valve and the first normally closed hydraulic control valve through the pipeline, causing the normally open hydraulic control valve to close and the first normally closed hydraulic control valve to open, thus disabling the damping adjustment. The oil then flows back from the rodless chamber to the bidirectional electric oil pump, lowering the suspension height.

[0030] Compared with existing technologies, the beneficial effects of this invention are reflected in:

[0031] 1. The fully active suspension provided by this invention can steplessly adjust its stiffness and damping characteristics, and always maintain a good driving experience for the vehicle under different loads, speeds and road conditions;

[0032] 2. This invention uses a hydraulic system to change the suspension height, which has a fast response speed and high control precision. It can adjust the suspension height under extreme conditions such as high-speed cornering, rapid acceleration and deceleration, and off-road driving, thereby improving the vehicle's handling stability.

[0033] 3. This invention uses a hydraulic control valve to replace some of the electronic control valves, which adjusts the damping of the disabled suspension during suspension height adjustment and ensures the correct flow of hydraulic fluid, thereby improving system reliability and the speed of height adjustment. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the fully active suspension of the present invention. Detailed Implementation

[0035] In this embodiment, as Figure 1 As shown, a fully active suspension with continuously adjustable stiffness, damping, and height includes a hydraulic cylinder, a gas spring, a stiffness adjustment line, and a hydraulic cylinder adjustment line.

[0036] The hydraulic cylinder has a plunger structure, which is divided into a rod chamber A-1 and a rodless chamber A-2 by the piston. Each chamber has an oil port. The piston rod of the hydraulic cylinder is connected to the unsprung mass.

[0037] The gas spring is divided into an air bladder chamber B-1 and an adjustment chamber B-3 by a floating piston B-2. A limiting ring B-4 is provided on the inner wall of the adjustment chamber B-3 to limit the position of the floating piston B-2 in the adjustment chamber B-3. The elastic diaphragm at the bottom of the air bladder chamber B-1 is connected to the top outer shell of the rodless chamber A-2, and the rigid outer shell of the gas spring is connected to the spring mass.

[0038] The oil inlet of regulating chamber B-3 is connected to the pump port of oil pump B-7 through check valve B-5. The oil suction port of oil pump B-7 is connected to oil tank B-8. The oil outlet of regulating chamber B-3 is connected to oil tank B-8 through electromagnetic proportional valve B-5 to form a stiffness regulating pipeline.

[0039] A first normally closed hydraulic control valve A-4-2, a bidirectional electric oil pump A-7, and a second normally closed hydraulic control valve A-4-3 are connected in series between the oil port of the rodless chamber A-1 and the oil port of the rod chamber A-2. A third check valve A-6-3 is connected in parallel to the two ends of the pipeline of the first normally closed hydraulic control valve A-4-2, and a fourth check valve A-6-4 is connected in parallel to the two ends of the pipeline of the second normally closed hydraulic control valve A-4-3. A first accumulator A-5-1 is connected to the pipeline between the oil port of the rodless chamber A-2 and the first normally closed hydraulic control valve A-4-2, and a second accumulator A-5-2 is connected to the pipeline between the oil port of the rod chamber A-1 and the second normally closed hydraulic control valve A-4-3. A solenoid proportional valve A-3... One end of the valve connected in series with the normally open hydraulic controlled valve A-4-1 is connected to the oil port of the rodless chamber A-2, and the other end is connected to the oil port of the rod chamber A-1; one end of the first check valve A-6-1 and the second check valve A-6-2 connected in parallel is connected to the control port of the normally open hydraulic controlled valve A-4-1, and the other end is connected to both ends of the bidirectional electric oil pump A-7; the control port of the first normally closed hydraulic controlled valve A-4-2 is connected in the pipeline between the bidirectional electric oil pump A-7 and the second check valve A-6-2, and the control port of the second normally closed hydraulic controlled valve A-4-3 is connected in the pipeline between the bidirectional electric oil pump A-7 and the first check valve A-6-1. The above connections form the hydraulic cylinder regulating pipeline.

[0040] Typically, we want suspension stiffness to adjust according to different road conditions and driving needs. When the road surface is smooth or the vehicle is in Sport mode, high stiffness helps improve the vehicle's handling stability and suspension support. When the road surface is rough or the vehicle is in Comfort mode, low stiffness effectively absorbs road impacts and maintains a superior ride comfort. This invention achieves stepless adjustment of suspension stiffness by changing the gas pressure in the airbag chamber. The airbag chamber can be considered as an air spring, and the air spring's supporting load can be simplified to F = (PP... a In formula A: F—support load; P—absolute gas pressure; P a —Standard atmospheric pressure; A—Effective working area. Assuming the gas in the airbag cavity is an ideal gas, PV can be obtained. n =const, where: n—polygonal exponent. The spring stiffness K can be obtained by differentiating the air spring load F with respect to the spring displacement x: The rate of change of the effective working area of ​​the piston is usually The air spring stiffness is very small and can be obtained by neglecting it. Therefore, changing the volume of the airbag cavity and the gas pressure can change its stiffness.

[0041] When stiffness is increased, the oil pump B-7 is controlled to pump oil from the oil tank B-8 and inject the oil into the regulating chamber B-3 through the one-way valve B-5, pushing the floating piston B-2 downward and compressing the airbag chamber B-1, thereby increasing the gas pressure in the airbag chamber B-1. When stiffness is decreased, the electromagnetic proportional valve B-6 is controlled to open, so that the oil flows back from the regulating chamber B-3 to the oil tank B-8, the floating piston B-2 moves upward, the airbag chamber B-1 expands, and the gas pressure in the airbag chamber B-1 decreases.

[0042] When a vehicle travels over an uneven road surface, the impact is transmitted from the wheels to the suspension system. The hydraulic cylinder piston reciprocates, and the hydraulic fluid dissipates energy as it flows through the electromagnetic proportional valve A-3, thus achieving vibration damping. The suspension damping can be adjusted by controlling the opening of the electromagnetic proportional valve A-3; a larger opening results in lower damping. The fully active suspension of this invention achieves adaptive damping adjustment through the following steps:

[0043] Step 1: Real-time acquisition of the vertical speed of the wheel and the vehicle body, and calculation of the difference between their speeds. If the difference does not exceed the set threshold, the electromagnetic proportional valve A-4-1 will maintain its opening. Otherwise, proceed to step 2.

[0044] Step 2: Determine the direction of the two velocities. If they are in the same direction, open the electromagnetic proportional valve A-4-1 proportionally to the difference in velocity. Otherwise, open the electromagnetic proportional valve A-4-1 inversely proportional to the difference in velocity.

[0045] In actual driving, it is often necessary to adjust the suspension height of a vehicle. For example, when driving at high speed on a good road, lowering the suspension height can effectively reduce air resistance. When driving in a curve, raising the height of the outer suspension can improve cornering stability. Adjusting the suspension height during rapid acceleration and deceleration can suppress vehicle pitching.

[0046] This invention adjusts the suspension height by changing the oil volume in the two chambers of a hydraulic cylinder through the operation of a bidirectional electric oil pump. When the bidirectional electric oil pump A-7 pumps oil and injects oil into the rodless chamber A-2 through the third one-way valve A-6-3, the oil simultaneously reaches the control ports of the normally open hydraulic control valve A-4-1 and the second normally closed hydraulic control valve A-4-3 through pipelines. The normally open hydraulic control valve A-4-1 closes and the second normally closed hydraulic control valve A-4-3 opens, causing the damping adjustment to fail. The oil flows back from the rod chamber A-1 to the bidirectional electric oil pump A-7, increasing the oil volume in the rodless chamber A-2 and the oil volume in the rod chamber A-1. As the piston rod moves downward, the suspension height increases. When the bidirectional electric oil pump A-7 pumps oil and injects it into the rod chamber A-1 through the fourth check valve A-6-4, the oil simultaneously reaches the control ports of the normally open hydraulic control valve A-4-1 and the first normally closed hydraulic control valve A-4-2 through pipelines. The normally open hydraulic control valve A-4-1 closes and the first normally closed hydraulic control valve A-4-2 opens, causing the damping adjustment to fail. The oil flows back from the rodless chamber A-2 to the bidirectional electric oil pump A-7, increasing the oil volume in the rod chamber A-1 and decreasing the oil volume in the rodless chamber A-2. The piston rod moves upward, causing the suspension height to decrease.

Claims

1. A fully active suspension with continuously adjustable stiffness, damping, and height, characterized in that, include: Hydraulic cylinder, gas spring, stiffness adjustment pipeline and hydraulic cylinder adjustment pipeline; The hydraulic cylinder is divided into a rod chamber (A-1) and a rodless chamber (A-2) by a piston, and the piston rod of the hydraulic cylinder is connected to the unsprung mass. The gas spring is divided into an air bladder chamber (B-1) and an adjustment chamber (B-3) by a floating piston (B-2), and a limiting ring (B-4) is provided on the inner wall of the adjustment chamber (B-3) to limit the position of the floating piston (B-2) in the adjustment chamber (B-3); the rigid outer shell of the gas spring is connected to the spring mass, and the elastic diaphragm at the bottom of the air bladder chamber (B-1) is connected to the top outer shell of the rodless chamber (A-2); The stiffness adjustment pipeline is connected to the inlet and outlet of the adjustment chamber (B-3) respectively, and is used to inject and discharge oil into the adjustment chamber (B-3); The stiffness adjustment pipeline includes: a one-way valve (B-5), a first electromagnetic proportional valve (B-6), an oil pump (B-7), and an oil tank (B-8); The oil inlet of the regulating chamber (B-3) is connected to the pump port of the oil pump (B-7) through the one-way valve (B-5), the oil suction port of the oil pump (B-7) is connected to the oil tank (B-8), and the oil outlet of the regulating chamber (B-3) is connected to the oil tank (B-8) through the first electromagnetic proportional valve (B-6). The hydraulic cylinder regulating pipeline is connected to the oil port of the rod chamber (A-1) and the oil port of the rodless chamber (A-2) respectively, for injecting and discharging oil into them, and realizing the flow of oil between the two chambers; The hydraulic cylinder regulating pipeline includes: a second electromagnetic proportional valve (A-3), a normally open hydraulic controlled valve (A-4-1), a first normally closed hydraulic controlled valve (A-4-2), a second normally closed hydraulic controlled valve (A-4-3), a first accumulator (A-5-1), a second accumulator (A-5-2), a first check valve (A-6-1), a second check valve (A-6-2), a third check valve (A-6-3), a fourth check valve (A-6-4), and a bidirectional electric oil pump (A-7); The first normally closed hydraulic control valve (A-4-2), the bidirectional electric oil pump (A-7), and the second normally closed hydraulic control valve (A-4-3) are connected in series between the oil port of the rodless chamber (A-2) and the oil port of the rod chamber (A-1). A third check valve (A-6-3) is connected in parallel to the two ends of the first normally closed hydraulic control valve (A-4-2), and a fourth check valve (A-6-4) is connected in parallel to the two ends of the second normally closed hydraulic control valve (A-4-3). The first accumulator (A-5-1) is connected to the pipeline between the oil port of the rodless chamber (A-2) and the first normally closed hydraulic controlled valve (A-4-2), and the second accumulator (A-5-2) is connected to the pipeline between the oil port of the rod chamber (A-1) and the second normally closed hydraulic controlled valve (A-4-3). One end of the second electromagnetic proportional valve (A-3) connected in series with the normally open hydraulic controlled valve (A-4-1) is connected to the oil port of the rodless chamber (A-2), and the other end is connected to the oil port of the rod chamber (A-1). One end of the first check valve (A-6-1) and the second check valve (A-6-2) connected in parallel is connected to the control port of the normally open hydraulic controlled valve (A-4-1), and the other end is connected to both ends of the bidirectional electric oil pump (A-7). The control port of the first normally closed hydraulic controlled valve (A-4-2) is connected in the pipeline between the bidirectional electric oil pump (A-7) and the second check valve (A-6-2); the control port of the second normally closed hydraulic controlled valve (A-4-3) is connected in the pipeline between the bidirectional electric oil pump (A-7) and the first check valve (A-6-1).

2. The fully active suspension according to claim 1, characterized in that, The working process of the stiffness adjustment pipeline includes: The oil pump (B-7) is controlled to pump oil from the oil tank (B-8) and inject the oil into the regulating chamber (B-3) through the one-way valve (B-5). The floating piston (B-2) moves down and compresses the air bladder chamber (B-1), thereby increasing the gas pressure in the air bladder chamber (B-1) and increasing the stiffness of the gas spring. The first electromagnetic proportional valve (B-6) is opened, causing the oil to return from the regulating chamber (B-3) to the oil tank (B-8). The floating piston (B-2) moves upward, and the air bladder chamber (B-1) expands, thereby reducing the gas pressure in the air bladder chamber (B-1) and decreasing the stiffness of the gas spring.

3. The fully active suspension according to claim 1, characterized in that, The damping adaptive adjustment is achieved through the following steps: Step 1: Real-time acquisition of the vertical speed of the wheel and the vehicle body, and calculation of the difference between their speeds. If the difference does not exceed the set threshold, the second electromagnetic proportional valve (A-3) will maintain its opening. Otherwise, proceed to step 2. Step 2: Determine the direction of the two velocities. If they are in the same direction, open the second electromagnetic proportional valve (A-3) proportionally to the difference in velocity. Otherwise, open the second electromagnetic proportional valve (A-3) inversely to the difference in velocity.

4. The fully active suspension according to claim 1, characterized in that, The hydraulic cylinder adjustment pipeline adjusts the suspension height through the following process: When the bidirectional electric oil pump (A-7) pumps oil and injects it into the rodless chamber (A-2) through the third check valve (A-6-3), the oil simultaneously reaches the control ports of the normally open hydraulic control valve (A-4-1) and the second normally closed hydraulic control valve (A-4-3) through the pipeline, causing the normally open hydraulic control valve (A-4-1) to close and the second normally closed hydraulic control valve (A-4-3) to open, thus disabling the damping adjustment. The oil then flows back from the rod chamber (A-1) to the bidirectional electric oil pump (A-7), raising the suspension height. When the bidirectional electric oil pump (A-7) pumps oil and injects it into the rod chamber (A-1) through the fourth check valve (A-6-4), the oil simultaneously reaches the control ports of the normally open hydraulic control valve (A-4-1) and the first normally closed hydraulic control valve (A-4-2) through the pipeline, causing the normally open hydraulic control valve (A-4-1) to close and the first normally closed hydraulic control valve (A-4-2) to open, thus disabling the damping adjustment. The oil then flows back from the rodless chamber (A-2) to the bidirectional electric oil pump (A-7), lowering the suspension height.

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