Rigidity self-control type ternary stepless controllable suspension and design and working method thereof

Abstract

The invention discloses a rigidity self-control type ternary stepless controllable suspension and a design and working method thereof in the technical field of automobiles, the upper end of a plunger or the lower end of an oil cylinder is outwards connected with a first electric ball valve, a first inerter pipe, a second inerter pipe and an oil gas chamber in sequence through an oil pipe, and the two ends of the second inerter pipe are connected with second electric ball valves in parallel; with the maximum opening degree of the first electric control ball valve and the minimum acceleration of a vehicle body in a wheel resonance frequency band as targets, simulating and calculating the opening degree of the second electric control ball valve, and constructing an air spring airbag pressure and second electric control ball valve opening degree table by combining 100% and 0% of the opening degrees of the second electric control ball valve; the corresponding opening degree is found in the opening degree table, the opening degree of the second electric control ball valve is controlled to be the found opening degree, the first electric control ball valve can enable system damping to be adjusted between 0 and infinity, small damping is provided to enable an automobile to obtain bad road driving riding comfort, and the second electric control ball valve enables system inerter to be adjusted between the minimum and the maximum in a stepless mode. And the automobile can obtain the driving and riding comfort on the bad road under any load.

Description

Technical Field

[0001] This invention belongs to the field of automotive technology and relates to the suspension structure of automobiles and its design and working method, specifically a controllable suspension for automobiles and its working method. Background Technology

[0002] The suspension is a crucial structural and functional component of a car. When a car travels on rough roads, it attenuates vibrations transmitted from the wheels to the body, providing passengers with a comfortable ride. To achieve effective suppression of high-frequency vibrations in the vehicle body, patent application CN202511235690.3, entitled "Integrated Stiffness-Damping Inertia-Capacity Self-Controlled Two-Stage Vibration-Reducing Hydro-Pneumatic Suspension and its Working Method," describes a hydro-pneumatic suspension using a dual-tube stiffness control valve integrated within a piston cylinder. This suspension automatically provides low stiffness and inertia within the suspension travel range for improving ride comfort, thus providing low-stiffness vibration isolation and high-frequency anti-resonance functions. Combined with the high-frequency vibration absorption function of the wheel dynamic shock absorbers, it significantly suppresses high-frequency vibrations transmitted from the road surface to the vehicle body. However, a problem exists: only one inertia tube provides inertia. When the vehicle load changes significantly, it cannot adjust the inertia according to the specific real-time load to achieve the best possible anti-resonance effect. Although the air spring with a dual-tube stiffness control valve built into the air bladder and piston, as described in patent application CN202510329235.3 entitled "A Compact Stiffness Self-Controlled Air Spring and its Working Method", can maintain a constant static travel when the vehicle load changes, automatically provide small stiffness within the suspension travel range for improving ride comfort, and automatically provide large stiffness outside the suspension travel range for improving ride comfort, it has the following problems: it does not have wheel dynamic shock absorbers and damping inertia adjustable dampers, it cannot form an independent suspension system, and it cannot adjust damping and inertia. Furthermore, the stiffness-controlled four-inertia element two-stage damping hydropneumatic suspension and its working method described in patent application CN202510268757.7 utilizes an adjustable flow valve connected in series with an inertia tube to adjust the damping of the suspension system. However, since the minimum damping achievable by existing adjustable flow valves generally cannot approach 0, the high-frequency vibration isolation capability of the suspension system deteriorates. Moreover, there is no second inertia tube to achieve stepless adjustment of the suspension system's inertia, thus failing to achieve better ride comfort under varying vehicle loads. Additionally, patent applications CN202511235690.3 and CN202510268757.7 do not provide design methods for parameters such as the suspension system's inertia and the stiffness and vibration absorption mass of the wheel dynamic shock absorbers. Summary of the Invention

[0003] The purpose of this invention is to solve the problems existing in the prior art and to propose a stiffness-controlled three-dimensional continuously variable suspension. At the same time, it proposes the design of the main parameters of the suspension and the working method of the suspension, so as to realize the quasi-infinitely variable adjustment of damping and inertia capacity with the change of vehicle load, and to ensure the best possible ride comfort and driving safety under different vehicle load conditions.

[0004] To achieve the above objectives, the technical solution adopted by the stiffness-controlled three-dimensional continuously variable suspension of the present invention is as follows: It includes a hydraulic cylinder, a plunger airbag, and a piston. A wheel dynamic shock absorber is fixed to the outer wall of the hydraulic cylinder. The lower part of the airbag is connected to the piston. A stiffness control valve is provided inside the airbag and piston. The lower part of the piston is connected to an external auxiliary air chamber through an air pipe. The lower end of the hydraulic cylinder is fixedly connected to the wheel via a wheel connecting device. A hollow plunger is provided inside the hydraulic cylinder, and the lower end of the plunger is provided with a plunger valve that divides the inner cavity of the hydraulic cylinder into upper and lower chambers. The piston has multiple through holes that connect the upper and lower chambers of the cylinder. The top of the piston is connected to the vehicle body, and the airbag is connected to the vehicle body upwards. The upper end of the piston or the lower end of the cylinder is connected to the first electric ball valve, the first inertial volume tube, the second inertial volume tube, and the oil-gas chamber in sequence through oil pipes. The second electric ball valve is connected in parallel at both ends of the second inertial volume tube. The cylinder, piston, first electric ball valve, second electric ball valve, first inertial volume tube, second inertial volume tube, and oil-gas chamber constitute a damping inertial volume continuously variable control shock absorber.

[0005] The design method for the stiffness-controlled three-dimensional continuously variable suspension adopts the following technical solution:

[0006] Step 1): Based on the unsprung mass m w and the equivalent stiffness k of the wheels and tires w The wheel vibration frequency was calculated without considering suspension stiffness.

[0007] Step 2): Based on the maximum working volume of the air spring when the car is unloaded and the air pressure p inside the airbag ss Calculate the air spring stiffness when the car is unloaded and in a balanced position. r0 is the effective working radius of the airbag, r1 is the radius of the piston, R is the heat exchange coefficient, and the maximum working volume of the air spring is the working volume V of the airbag. p The volume V of the piston s and the volume V of the additional air chamber a sum;

[0008] Step 3): Calculate the damper stiffness generated by the oil-gas chamber. V p0 P is the working volume of the oil and gas chamber. p0 P is the factory charging pressure for the oil and gas chamber. p1 S is the initial filling pressure of the hydraulic cylinder. pWhere L is the effective working area of ​​the plunger, and L is the maximum extension stroke of the shock absorber.

[0009] Step 4): Calculate the inertial capacity of the first inertial tube. Air spring stiffness when the car is fully loaded and in a balanced position and the sum of the inertial capacities of the first and second inertial tubes. The inertial capacity m of the second inertial tube e2 =m e3 -m e1 ;λ s λ is the lever ratio for the air spring mounting on the axle. d p is the mounting lever ratio of the shock absorber on the axle. sb It is the airbag pressure when the car is fully loaded before driving;

[0010] Step 5): Calculate any load m between no-load and full-load conditions. vr air spring airbag pressure value at time and the corresponding suspension system stiffness m0 is the sprung mass of the car when it is unloaded;

[0011] Step 6): When the car is unloaded, the air spring pressure p su And the air spring airbag pressure p when fully loaded sb Set n-2 equidistant pressure points between them 1≤i≤n-2, i=0 for no load, i=n for full load, n is at least greater than 20, calculate the air spring stiffness under these conditions. and the corresponding suspension system stiffness

[0012] Step 7): With the goal of maximizing the opening of the first electronically controlled ball valve and minimizing the vehicle body acceleration within the wheel resonance frequency band, simulate and calculate the opening α of the second electronically controlled ball valve. i By combining the opening degrees of the second electrically controlled ball valve at 100% and 0%, a table is constructed to show the pressure of the air spring bladder and the opening degree of the second electrically controlled ball valve.

[0013] The technical solution adopted in the working method of the stiffness-controlled three-dimensional continuously variable suspension is as follows:

[0014] Step A): Before driving, find the air spring pressure value in the air spring pressure gauge that matches the real-time air spring pressure p. sr The nearest pressure value p srj and the corresponding opening α rj The opening degree of the second electrically controlled ball valve is controlled at the found opening degree α. rj ;

[0015] Step B): When the car is driving on a rough road, maintain the opening α of the second electronically controlled ball valve.rj The control remains unchanged, keeping the first electrically controlled ball valve in the fully open state; when the oil cylinder moves relative to the plunger, the oil flows back and forth through the parallel oil circuit of the first electric ball valve, the first inertial tube, the second inertial tube and the second electric ball valve to the oil-gas chamber 3 to generate real-time hydraulic inertial capacity, and the stiffness is generated by the air pressure in the oil-gas chamber.

[0016] Step C): When the car is traveling at high speed on a good road, maintain the opening degree α of the second electronically controlled ball valve. rj The opening degree of the first electrically controlled ball valve remains unchanged between 5% and 10%.

[0017] Step D): When the car is traveling at medium speed on city roads under normal conditions (non-bad roads and non-high-speed driving), and when the car is traveling at low speed on extremely bad roads, maintain the opening degree α of the second electronically controlled ball valve. rj The opening degree of the first electrically controlled ball valve remains unchanged between 15% and 30%.

[0018] Further, in step B), when road surface unevenness causes the wheel to vibrate at high frequency, while the cylinder moves relative to the plunger, and the piston moves relative to the airbag and the suspension travel is within the travel range of the ride comfort improvement suspension, the compressed air in the airbag communicates with the piston and the auxiliary air chamber through the stiffness control valve. At this time, the airbag, piston, and the compressed air in the auxiliary air chamber work together to output a smaller suspension stiffness. The wheels transmit high-frequency vibrations from the vehicle body, which are then isolated with relatively low stiffness. Simultaneously, the air pressure in the oil and gas chamber generates stiffness k. d The combined suspension system has a stiffness of The suspension system's stiffness, combined with real-time hydraulic inertia, generates anti-resonance, suppressing high-frequency anti-resonance vibrations transmitted from the wheels to the vehicle body.

[0019] The beneficial effects of adopting the above technical solution in this invention are:

[0020] (1) Compared with the "Stiffness Self-Controlled Four-Inertia Element Two-Stage Vibration Damping Hydro-Pneumatic Suspension and Working Method" provided in the document with patent application number CN202510268757.7 and the "Integrated Stiffness Damping Inertial Capacity Self-Controlled Two-Stage Vibration Damping Hydro-Pneumatic Suspension and Working Method" with application number CN202511235690.3, the present invention uses a first electronically controlled ball valve to generate a small damping close to 0 when the opening degree is equal to 100%, which is more conducive to improving the vibration isolation effect of the entire suspension system, enabling the car to obtain the best possible ride comfort on bad roads, and is more conducive to providing large damping to enable the car to obtain the best possible safety on good roads.

[0021] (2) Compared with the “stiffness self-controlled four-inertia element two-stage vibration damping hydro-air suspension and working method” provided in the document with patent application number CN202510268757.7, the second electronically controlled ball valve adopted by this invention can make the system inertia capacity steplessly adjustable between the minimum and the maximum, which is more conducive to the vehicle to obtain the best possible ride comfort on bad roads under any load.

[0022] (3) Compared with the document “A Compact Stiffness Self-Controlled Air Spring and its Working Method” provided by patent application number CN202510329235.3, this invention provides a complete suspension system that can obtain better ride comfort on bad roads and safety on good roads under any vehicle load.

[0023] (4) Compared with the "Stiffness Self-Controlled Four-Inertia Element Two-Stage Vibration Damping Hydro-Pneumatic Suspension and Working Method" provided in the document with patent application number CN202510268757.7 and the "Integrated Stiffness Damping Inertia Capacity Self-Controlled Two-Stage Vibration Damping Hydro-Pneumatic Suspension and Working Method" with application number CN202511235690.3, the present invention provides a detailed design method for parameters such as suspension system inertia capacity and stiffness and vibration absorption mass of wheel dynamic shock absorbers, so that the suspension can obtain the best possible ride comfort under any load of the car. Attached Figure Description

[0024] Figure 1 This is a structural schematic diagram of the stiffness-controlled three-dimensional continuously variable suspension of the present invention;

[0025] In the diagram: 1. Vehicle body; 2. First electric ball valve; 3. Oil-gas chamber; 4. Second inertial flow tube; 5. Second electric ball valve; 6. First inertial flow tube; 7. Wheel dynamic shock absorber; 7-1. First buffer block; 7-2. Second buffer block; 8. Plunger; 9. Hydraulic cylinder; 10. Wheel; 11. Wheel connection device; 12. Auxiliary air chamber; 13. Piston; 14. Stiffness control valve; 15. Airbag. Detailed Implementation

[0026] like Figure 1 As shown, the stiffness-controlled three-dimensional continuously variable suspension of the present invention includes a damping inertia-capacitance continuously variable shock absorber, a stiffness-controlled air spring, and a wheel dynamic shock absorber.

[0027] The damping inertial capacitance continuously variable shock absorber includes a hydraulic cylinder 9, a plunger 8, a first electric ball valve 2, a second electric ball valve 5, a first inertial capacitance tube 6, a second inertial capacitance tube 4, and an oil-gas chamber 3. The hydraulic cylinder 9 is axially arranged vertically, with its lower end fixedly connected to a wheel connection device 11, which in turn connects to a wheel 10. The hydraulic cylinder 9 contains a plunger 8, which is hollow. A cylinder piston is located at the lower end of the plunger 8, forming a coaxial sliding pair with the inner wall of the hydraulic cylinder 9, dividing the inner cavity of the hydraulic cylinder 9 into upper and lower chambers. Multiple through holes on the plunger piston allow hydraulic oil in the upper and lower chambers of the hydraulic cylinder 9 to communicate. The top of the plunger 8 is connected to the vehicle body 1. The upper end of the plunger 8 or the lower end of the hydraulic cylinder 9 is sequentially connected to the first electric ball valve 2, the first inertial capacitance tube 6, the second inertial capacitance tube 4, and the oil-gas chamber 3 via oil pipes. The second electric ball valve 5 is connected in parallel at both ends of the second inertial capacitance tube 4.

[0028] The aforementioned stiffness-controlled air spring includes an airbag 15, a piston 13, a stiffness control valve 14, and an auxiliary air chamber 12. The airbag 15 is connected upwards to the vehicle body 1, and its lower part is connected to the piston 13. The stiffness control valve 14 is located inside both the airbag 15 and the piston 13. The stiffness control valve 14 employs a dual-cylinder stiffness control valve structure as described in patent applications CN202511235690.3 or CN202510329235.3, consisting of an inner cylinder and an outer cylinder. The upper end of the inner cylinder of the stiffness control valve 14 is connected to the top of the airbag 15, and its lower end extends downwards through the top of the piston 13 and into the interior of the piston 13. The top of the outer cylinder of the stiffness control valve 14 is fixed to the top end face of the piston 14 and coaxially sleeved outside the inner cylinder. The lower part of the piston 13 is connected to the external auxiliary air chamber 12 via an air pipe. The installation positions of the airbag 15 and the piston 13 between the vehicle body 1 and the wheel 10 are interchangeable.

[0029] The structure of the wheel dynamic vibration absorber 7 adopts the wheel dynamic vibration absorber provided in the document with patent application number CN202511235690.3 and title "Integrated stiffness damping inertial capacity self-controlled two-stage vibration reduction hydro-air suspension and working method". It includes a first baffle, a first buffer block 7-1, a vibration absorption mass, a second buffer block 7-2 and a second baffle arranged coaxially on the upper and lower sides. The wheel dynamic vibration absorber 7 is fixed to the outer wall of the oil cylinder 9 by two clamps at the first baffle and the second baffle.

[0030] The main parameters affecting the stiffness-controlled three-dimensional continuously variable suspension of this invention include the vibration-absorbing mass m of the wheel dynamic shock absorber 7. a and anti-resonance frequency f a The air spring stiffness k of a car when it is unloaded and fully loaded and the car body is in a balanced position. ss and k sb The damper stiffness k generated by oil and gas chamber 3 dThe inertial capacity value m of the first inertial tube 2 and the second inertial tube 4 e1 and m e2 When the vehicle is under any load value between unloaded and fully loaded, m vr The corresponding air spring airbag pressure value p vr The table shows the relationship between the suspension system stiffness k2, the air spring pressure, and the opening degree of the second electronically controlled ball valve 5. Details are as follows:

[0031] 1. Based on the known unsprung mass m w and the equivalent stiffness k of the wheels and tires w The wheel vibration frequency was calculated without considering suspension stiffness.

[0032] Based on the unsprung mass m w Select the vibration absorption mass m of the wheel dynamic vibration absorber 7 a Vibration-absorbing mass m a The range is [0.08, 0.12]m w between.

[0033] Based on the wheel vibration frequency f w Select the vibration absorption frequency f of the wheel dynamic vibration absorber 7. a1 The vibration frequency f a1 The range is [0.6, 1.2]f w Between. When the vibration frequency f a1 Equal to the wheel vibration frequency f w At that time, the wheel dynamic vibration absorber 7 has the best vibration absorption effect.

[0034] Based on the vibration absorption frequency f a1 The vibration absorption mass m of the wheel dynamic vibration absorber 7 a The stiffness k of the first buffer block 7-1 and the second buffer block 7-2 was calculated. a =(2πf a1 ) 2 m a The first buffer block 7-1 and the second buffer block 7-2 have the same stiffness k. a .

[0035] 2. Based on the maximum working volume of the air spring when the car is unloaded and the air pressure p inside the airbag 15 ss Calculate the air spring stiffness when the car is unloaded and the body is in a balanced position. r0 is the effective working radius of airbag 15, r1 is the radius of piston 13, R is the heat exchange coefficient, which is generally taken as 1.4, and the maximum working volume of the air spring is the working volume V of airbag 15. p Piston 13 Volume V s and the volume V of the additional air chamber 12 a The sum of, i.e., Vp +V s +V a .

[0036] According to the formula Calculate the damper stiffness k generated by oil-gas chamber 3. d , where V p0 P is the working volume of oil and gas chamber 3; p0 The oil and gas chamber 3 is designed with a bladder-type accumulator, which is the factory charging pressure for the oil and gas chamber 3; P p1 S is the initial oil filling pressure of cylinder 9; p The effective working area of ​​plunger 8; L is the maximum extension stroke of the damper; and the anti-resonance frequency f is... a2 In [0.9 1.1]f w The frequency is selected between these values, when the anti-resonance frequency f is... a2 Equal to the wheel vibration frequency f w When the suspension system is in operation, it can achieve the best anti-resonance vibration damping effect.

[0037] According to the air spring stiffness k ss Vibration damper stiffness k d and anti-resonance frequency f a2 The inertial capacity value of the first inertial tube 2 was calculated. Where, λ s λ is the lever ratio for the air spring mounting on the axle. d This refers to the lever ratio for installing the shock absorber on the axle.

[0038] 3. Based on the airbag pressure p when the car is fully loaded before driving. sb The maximum working volume V of the air spring p +V s +V a Based on the effective working radius r0 of the airbag 15 and the radius r1 of the piston 13, the air spring stiffness when the car is fully loaded and the vehicle body is in a balanced position is calculated.

[0039] According to the anti-resonance frequency f a2 air spring stiffness k sb Vibration damper stiffness k d And the mounting lever ratio λ of the air spring and shock absorber on the axle s , λ d The sum of the inertial capacities of the first inertial tube 6 and the second inertial tube 4 was calculated. Thus, the inertial capacity value m of the second inertial tube 4 is obtained. e2 =m e3 -m e1 m e1 It is the inertial capacity value of the first inertial capacity tube 2.

[0040] When the vehicle load is any load m between empty and fully loaded vr At that time, due to the load m vr The load can be any value between empty and fully loaded vehicles, thus achieving stepless load distribution between empty and fully loaded vehicles. Since the vehicle height remains constant, the load value m can be calculated. vr Corresponding to a uniquely determined air spring airbag pressure value m0 is the sprung mass of the vehicle when unloaded. Then, based on any load value, the air spring pressure value p... vr Vibration damper stiffness k d The effective working radius r0 of the airbag 15 and the radius r1 of the piston 13, and the maximum working volume V of the air spring. p +V s +V a The mounting lever ratio λ of the air spring and shock absorber on the axle s , λ d Calculate the stiffness of the uniquely determined suspension system. Because p vr In p ss and p sb There is no stepless change, therefore exist and The interval is infinitely variable, thus making k2 in and There is no step change.

[0041] The present invention designs the inertial capacity m of the first inertial capacity tube 2 when the car is unloaded. e1 The inertial capacity m of the second inertial tube 4 when the car is fully loaded e2 The stiffness k of the first buffer block 7-1 and the second buffer block 7-2 a At that time, the corresponding wheel and tire equivalent stiffness k w Wheel vibration frequency deviation without considering suspension stiffness Instead of the wheel vibration frequency given in commonly used textbooks (Automotive Theory (6th Edition), edited by Yu Zhisheng and Xia Qunsheng, Machinery Industry Press, January 2019). (k2 is the suspension stiffness). This is because when the suspension stiffness and damping change arbitrarily, the amplitude-frequency response curve of the sprung mass displacement versus road input of a conventional single-stage damping suspension will inevitably pass through the point... (m2 is the sprung mass), and it is located in the high-frequency range of suspension vibration. Therefore, this point is the optimal point of the optimized sprung mass displacement amplitude-frequency characteristic curve in the high-frequency range. Therefore, [the following is a partial translation of the original text, which is incomplete and requires further context]. Named the high-frequency fixed point of the spring-loaded mass displacement amplitude-frequency characteristic, and assign the corresponding design inertia capacitance m. e1 m e2 and stiffness k aThe design method is named the parametric design method based on the high-frequency fixed point of the amplitude-frequency characteristic of the spring-loaded mass displacement.

[0042] 4. Air spring pressure p when the car is unloaded ss And the air spring airbag pressure p when fully loaded sb Set n-2 equidistant pressure points between them Where 1≤i≤n-2, i=0 represents no load, i=n represents full load, and n must be at least 20 greater than 20, for example, n=100, to calculate the air spring stiffness at this time. Then the corresponding suspension system stiffness is calculated.

[0043] With the goal of maximizing the opening of the first electronically controlled ball valve 2 and minimizing the vehicle body acceleration within the wheel resonance frequency band, the opening α of the second electronically controlled ball valve 5 is simulated and calculated. i , 1≤i≤n-2; Combining the opening degrees of the two second electrically controlled ball valves 5 (100% and 0%), construct a 2 to n-dimensional air spring bladder pressure and second electrically controlled ball valve 5 opening degree table, as shown in Table 1 below:

[0044] Table 1

[0045]

[0046] When the suspension designed according to the above method is used in a car, before the car is driven, the air spring airbag pressure value in the first row of Table 1 is selected to match the real-time air spring airbag pressure p. sr The nearest pressure value p srj Then, find the corresponding opening degree α in the second row of Table 1, specifically in the row representing the opening degree of the second electrically controlled ball valve 5. rj Control the opening of the second electrically controlled ball valve 5 to the found opening degree α. rj .

[0047] Depend on Figure 1 It can be seen that when the opening degree of the second electrically controlled ball valve 5 is 100%, only the first inertial capacitance tube 6 is active, and the inertial capacitance value of the damping inertial capacitance stepless controllable shock absorber is m. e1 When the opening degree of the second electrically controlled ball valve 5 is 0%, the first inertial capacity tube 6 and the second inertial capacity tube 4 work together in pure series, and the inertial capacity value of the damping inertial capacity stepless controllable shock absorber is m. e3 It is the sum of the inertial capacities of the two inertial tubes; when the midpoint value α of the opening of the second electrically controlled ball valve 5... i At that time, some oil flows through the second inertial capacity pipe 4, and the real-time inertial capacity m of the damping inertial capacity continuously variable control shock absorber... er In m e1 With m e3 The inertia of the suspension system can be approximated by the variation between n and m when n is large enough. e1 With m e3 There is no step change.

[0048] When the car is driving on a rough road, maintain the opening α of the second electronically controlled ball valve 5. rj The control remains unchanged, keeping the first electrically controlled ball valve 2 fully open. When road unevenness causes the wheel 10 to vibrate at high frequency, this high-frequency vibration is transmitted from the wheel 10 to the cylinder 9 and piston 13 via the wheel connection device 11. Looking at the vibration path through the cylinder 9, since the wheel power vibration absorber 7 is fixedly connected to the cylinder 9 at two points via clamps, and its natural vibration frequency is different from the wheel vibration deflection frequency f... w Since they are similar, the wheel dynamic vibration absorber 7 absorbs part of the vibration transmitted from the wheel 10. When the cylinder 9 moves relative to the plunger 8, the oil flows back and forth between the fully open first electric ball valve 2, the first inertia pipe 2, the second inertia pipe 4, and the second electric ball valve 5 in parallel oil circuit to the oil-gas chamber 3, generating real-time hydraulic inertia m. er The stiffness k is generated by the gas pressure in the oil and gas chamber 3. d On the other hand, while the cylinder 9 moves relative to the plunger 8, from the vibration path passing through the piston 13, when the piston 13 moves relative to the airbag 15, and the suspension travel is within the range of the ride comfort improvement suspension travel (the definition of ride comfort improvement suspension travel can be found in the patent application CN202511235690.3, entitled "Integrated Stiffness Damping Inertia Capacity Self-Controlled Two-Stage Vibration Reduction Hydro-Pneumatic Suspension and Working Method", where the upper edge of the third row of holes in the inner cylinder is not lower than the lower edge of the second row of holes in the outer cylinder, and the lower edge of the second row of holes in the inner cylinder is not higher than the upper edge of the first row of holes in the outer cylinder), the compressed air in the airbag 15 communicates with the piston 13 and the auxiliary air chamber 12 through the stiffness control valve 14. At this time, the airbag 15 works together with the compressed air in the piston 13 and the auxiliary air chamber 12, outputting a smaller suspension stiffness. (This is the actual stiffness.) It is based on Refer to the table to determine the opening degree α of the second electrically controlled ball valve 5. rj (Approximate stiffness) to achieve low-stiffness vibration isolation of the high-frequency vibration transmitted from the wheel 10 to the body 1, while generating stiffness k with the air pressure in the oil-gas chamber 3. d The combined suspension system has a stiffness of ( (Similarly, the actual stiffness) is the same as the real-time hydraulic inertia capacity (m). er By combining the anti-resonance function, the vibration transmitted from the wheel 10 to the body 1 is suppressed by high-frequency anti-resonance, thereby achieving a significant reduction in high-frequency vibration transmitted from the wheel 10 to the body 1 by utilizing wheel dynamic vibration absorption, low stiffness vibration isolation, and high-frequency anti-resonance.

[0049] When the suspension travel exceeds the ride comfort improvement zone, the stiffness control valve 14 cuts off the flow of compressed air between the airbag 15, the piston 13, and the auxiliary air chamber 12 (the working principle can be found in the patent application CN202511235690.3, entitled "Integrated stiffness damping inertial capacity self-controlled two-stage damping hydropneumatic suspension and its working method"). At this time, only the compressed air in the airbag 15 works, providing greater suspension stiffness, hindering the increase of suspension travel, preventing the suspension limit from being impacted, and enabling the car to obtain the most comfortable ride on rough roads. This mode is the comfort working mode of the suspension.

[0050] When the car is traveling at high speed on a good road, maintain the opening α of the second electronically controlled ball valve 5. rj The system remains unchanged, controlling the first electronically controlled ball valve 2 to be in a critically locked state. The opening degree of the first electronically controlled ball valve 2 in the critically locked state is between 5% and 10%. For example, the opening degree of the first electronically controlled ball valve 2 of a car with a high body can be selected as 5%, while the opening degree of the first electronically controlled ball valve 2 of a car with a low body can be selected as 10%. Other cars can select the opening degree of the first electronically controlled ball valve 2 between 5% and 10% according to the specific body height, so that the shock absorber is in a critically locked state. When accelerating or decelerating, or when combined with steering, the car bears longitudinal or centrifugal inertial forces, and when encountering crosswinds and the car bears lateral forces, the vehicle body remains basically unchanged, so that the car can achieve good road driving safety. This mode is the safe working mode of the suspension.

[0051] When the car is traveling at a moderate speed on a city road under normal conditions (not on rough roads or at high speeds), the opening degree α of the second electronically controlled ball valve 5 should be maintained. rj The first electronically controlled ball valve 2 remains unchanged, operating in a general mode. In this mode, the opening of the first electronically controlled ball valve 2 is between 15% and 30%. For example, for cars with taller bodies, the opening of the first electronically controlled ball valve 2 can be selected as 15%, while for cars with shorter bodies, the opening can be selected as 30%. For other cars, the opening of the first electronically controlled ball valve 2 can be selected between 15% and 30% depending on the specific vehicle height. This allows the first electronically controlled ball valve 2 to provide appropriate damping, balancing ride comfort and vehicle stability. This is the general operating mode for the suspension. Therefore, depending on the vehicle height, the opening of the second electronically controlled ball valve 5 can be steplessly selected between [5% / 10%] and [15% / 30%], ensuring the car achieves the best possible ride comfort and driving safety.

[0052] When a car is traveling at low speed on extremely rough roads, in order to maintain the stability of the vehicle's posture, the opening α of the second electronically controlled ball valve 5 must be maintained. rj The control remains unchanged, and the first electrically controlled ball valve 2 is in a general operating condition. The opening degree of the first electrically controlled ball valve 2 is between 15% and 30%, that is, the general working mode of the suspension is adopted.

[0053] In this invention, the opening degree of the first electrically controlled ball valve 2 is infinitely adjustable with damping between 5%-10% and 15%-30% outside 100%, which is called one-dimensional infinitely controllable. (Vehicle load m) vr Corresponding to a uniquely determined air spring airbag pressure value This makes the suspension system stiffness exist and The stepless change between parameters is called binary stepless controllability. Based on the vehicle load m... vr The change alters the opening degree of the second electrically controlled ball valve 5, thereby enabling real-time inertial capacitance (m) controllable by the damping inertial capacitance stepless controllable damper. er In m e1 With m e3 The stepless adjustment between these parameters is called a three-dimensional continuously variable control, therefore the suspension of this invention is a stiffness self-control type three-dimensional continuously variable control suspension.

[0054] For the commonly used comfort mode, safety mode, and general mode in automobiles, this invention sets up three buttons or three-position levers on the steering wheel to correspond to the three modes, so that drivers can choose the working mode of the suspension system in a timely manner according to the specific road conditions to obtain a better suspension working effect.

Claims

1. A stiffness-controlled three-dimensional continuously variable suspension, comprising a cylinder (9), a plunger (8), an airbag (15), and a piston (13), wherein a wheel dynamic shock absorber (7) is fixed on the outer wall of the cylinder (9), the lower part of the airbag (15) is connected to the piston (13), a stiffness control valve (14) is provided inside the airbag (15) and the piston (13), and the lower part of the piston (13) is connected to an external auxiliary air chamber (12) through an air pipe; the lower end of the cylinder (9) is fixedly connected to the wheel via a wheel connecting device (11), a hollow plunger (8) is provided inside the cylinder (9), the lower end of the plunger (8) is provided with a plunger piston that divides the inner cavity of the cylinder (9) into upper and lower chambers, the plunger piston is provided with multiple through holes that allow the upper and lower chambers of the cylinder (9) to communicate, the top of the plunger (8) is connected to the vehicle body, and the airbag (15) is connected upward to the vehicle body, characterized in that: The upper end of the plunger (8) or the lower end of the cylinder (9) is connected outward through an oil pipe to the first electric ball valve (2), the first inertial volume tube (6), the second inertial volume tube (4) and the oil-gas chamber (3). The second electric ball valve (5) is connected in parallel at both ends of the second inertial volume tube (4). The cylinder (9), plunger (8), first electric ball valve (2), second electric ball valve (5), first inertial volume tube (6), second inertial volume tube (4) and oil-gas chamber (3) form a damping inertial volume stepless controllable shock absorber.

2. A design method for a stiffness-controlled three-dimensional continuously variable suspension as described in claim 1, characterized in that... Includes the following steps: Step 1): Based on the unsprung mass m w and the equivalent stiffness k of the wheels and tires w The wheel vibration frequency was calculated without considering suspension stiffness. Step 2): Based on the maximum working volume of the air spring when the car is unloaded and the air pressure p in the airbag (15) ss Calculate the air spring stiffness when the car is unloaded and in a balanced position. r0 is the effective working radius of the airbag (15), r1 is the radius of the piston (13), R is the heat exchange coefficient, and the maximum working volume of the air spring is the working volume V of the airbag (15). p The volume V of piston (13) s and the volume V of the additional air chamber (12) a sum; Step 3): Calculate the damper stiffness generated by the oil-gas chamber (3). V p0 P is the working volume of the oil and gas chamber (3). p0 The factory charging pressure of the oil and gas chamber (3), P p1 S is the initial oil filling pressure of the oil cylinder (9). p L is the effective working area of ​​the plunger (8), and L is the maximum extension stroke of the damper. Step 4): Calculate the inertial capacity of the first inertial tube (2). Air spring stiffness when the car is fully loaded and in a balanced position and the sum of the inertial capacities of the first inertial tube (6) and the second inertial tube (4). The inertial capacity m of the second inertial tube (4) e2 =m e3 -m e1 ;λ s λ is the lever ratio for the air spring mounting on the axle. d p is the mounting lever ratio of the shock absorber on the axle. sb It is the airbag pressure when the car is fully loaded before driving; Step 5): Calculate any load m between no-load and full-load conditions. vr air spring airbag pressure value at time and the corresponding suspension system stiffness m0 is the sprung mass of the car when it is unloaded; Step 6): When the car is unloaded, the air spring pressure p su And the air spring airbag pressure p when fully loaded sb Set n-2 equidistant pressure points between them i = 0 represents no load, i = n represents full load, and n must be at least greater than 20. Calculate the air spring stiffness under these conditions. and the corresponding suspension system stiffness Step 7): With the goal of maximizing the opening of the first electronically controlled ball valve (2) and minimizing the vehicle body acceleration within the wheel resonance frequency band, simulate and calculate the opening α of the second electronically controlled ball valve (5). i By combining the opening degrees of the second electrically controlled ball valve (5) at 100% and 0%, a table of air spring bladder pressure and the opening degree of the second electrically controlled ball valve (5) is constructed.

3. The design method according to claim 2, characterized in that: Based on the unsprung mass m w Select the vibration absorption mass m of the wheel dynamic vibration absorber (7) a Vibration-absorbing mass m a The range is [0.08, 0.12]m w Between, according to the wheel vibration deflection frequency f w Select the absorption frequency f of the wheel dynamic vibration absorber (7) a1 absorption frequency f a1 The range is [0.6, 1.2]f w between.

4. The design method according to claim 3, characterized in that: When the vibration absorption frequency f a1 Equal to the wheel vibration frequency f w At that time, the wheel dynamic vibration absorber (7) has the best vibration absorption effect.

5. The design method according to claim 3, characterized in that: The wheel dynamic vibration absorber (7) has a first buffer block and a second buffer block arranged coaxially, based on the vibration absorption frequency f. a1 The vibration absorption mass m of the wheel dynamic vibration absorber (7) a The stiffness k of the first buffer block and the second buffer block (7) is calculated. a =(2πf a1 ) 2 m a The first and second buffer blocks have the same stiffness k. a .

6. The design method according to claim 2, characterized in that: Anti-resonance frequency f a2 In [0.9 1.1]f w The frequency is selected between these values, when the anti-resonance frequency f is... a2 Equal to the wheel vibration frequency f w At this time, the suspension system achieves the optimal anti-resonance vibration damping effect.

7. A method for operating a suspension obtained by the design method according to claim 2, characterized in that... include: Step A): Before driving, find the air spring pressure value in the air spring pressure gauge that matches the real-time air spring pressure p. sr The nearest pressure value p srj and the corresponding opening α rj The opening degree of the second electrically controlled ball valve (5) is controlled at the found opening degree α. rj ; Step B): When the car is driving on a bad road, maintain the opening α of the second electronically controlled ball valve (5). rj The control remains unchanged, and the first electric ball valve (2) is in the fully open state. When the oil cylinder (9) moves relative to the plunger (8), the oil flows back and forth between the oil and gas chamber (3) through the parallel oil circuit of the first electric ball valve (2), the first inertial capacity pipe (2), the second inertial capacity pipe (4) and the second electric ball valve (5) to generate real-time hydraulic inertial capacity, and the stiffness is generated by the air pressure of the oil and gas chamber (3). Step C): When the car is traveling at high speed on a good road, maintain the opening α of the second electronically controlled ball valve (5). rj The opening degree of the first electrically controlled ball valve (2) remains unchanged between 5% and 10%. Step D): When the car is traveling at a medium speed on a normal, non-bad road and a non-high-speed road in the city, and when the car is traveling at a low speed on a very bad road, maintain the opening α of the second electronically controlled ball valve (5). rj The opening degree of the first electrically controlled ball valve (2) remains unchanged between 15% and 30%.

8. The working method according to claim 7, characterized in that: In step B), when road surface unevenness causes the wheel to vibrate at high frequency, while the cylinder (9) moves relative to the plunger (8), and the piston (13) moves relative to the airbag (15) and the suspension travel is within the travel range of the ride comfort improvement suspension, the compressed air in the airbag (15) communicates with the piston (13) and the auxiliary air chamber (12) through the stiffness control valve (14). At this time, the compressed air in the airbag (15), piston (13), and auxiliary air chamber (12) work together to output a smaller suspension stiffness. The high-frequency vibration transmitted from the wheels to the vehicle body is isolated with low stiffness, while the air pressure in the oil-gas chamber (3) generates stiffness k. d The combined suspension system has a stiffness of The suspension system's stiffness, combined with real-time hydraulic inertia, generates anti-resonance, suppressing high-frequency anti-resonance vibrations transmitted from the wheels to the vehicle body.

9. The working method according to claim 7, characterized in that: In step C), the opening degree of the first electronically controlled ball valve (2) of the car with a higher body is selected as 5%, the opening degree of the first electronically controlled ball valve (2) of the car with a lower body is selected as 10%, and the opening degree of the first electronically controlled ball valve (2) of other cars is selected between 5% and 10% according to the specific body height; In step D), the opening degree of the first electronically controlled ball valve (2) of the car with a higher body is selected as 15%, the opening degree of the first electronically controlled ball valve (2) of the car with a lower body is selected as 30%, and the opening degree of the first electronically controlled ball valve (2) of other cars is selected between 15% and 30% according to the specific body height.

10. The working method according to claim 7, characterized in that: For the commonly used comfort mode, safety mode, and general mode of automobiles, three buttons or three-position levers are set on the car steering wheel to correspond to the three modes.

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