Hydraulic suspension system and method for operating the system

Abstract

Methods and systems for a hydraulic vehicle suspension are provided. In one example, a hydraulic suspension system includes a first manifold including, for each of a first hydraulic cylinder and a second hydraulic cylinder, a piston-side port and a rod-side port fluidly coupled to a piston chamber and a rod chamber, respectively. In the system, the first manifold includes a first electrically activated valve fluidly coupled to the piston-side port, a first damping device, and a second damping device, the first electrically activated valve configured to lock and unlock vertical motion of the first hydraulic cylinder and the second hydraulic cylinder, and the first electrically activated valve allowing fluid communication between the first hydraulic cylinder and the second hydraulic cylinder when vertical motion of the first hydraulic cylinder and the second hydraulic cylinder is locked to allow free rolling motion in the hydraulic suspension system.

Description

Technical Field

[0001] This disclosure generally relates to a hydraulic suspension system with a manifold and a method for operating the hydraulic suspension system. Background Technology

[0002] Some vehicles utilize suspension arrangements, such as a separate front suspension, to achieve various handling characteristics. Some suspension systems utilize double-acting hydraulic cylinders capable of adjusting vehicle handling. In certain systems, double-acting cylinders for adjusting suspension spring rate have been experimented with.

[0003] Bauer's US 7,059,127 B2 discloses a hydropneumatic spring support arrangement for agricultural machinery. This spring support arrangement changes the spring rate of the device during ballast adjustment to adapt the spring rate to dynamic vehicle ballast conditions.

[0004] The inventors have recognized several drawbacks of Bauer's hydropneumatic suspension system and other vehicle suspension systems. Bauer's system requires simultaneous adjustment of the vehicle's suspension spring rate and ballast. Furthermore, because it eliminates control schemes designed to avoid unwanted overlapping kinematic patterns, Bauer's system may exhibit undesirable handling characteristics. Other vehicle hydraulic suspension systems attempt to deploy complex control circuitry designed to mitigate certain handling characteristics. However, these systems can be complex and highly dependent on sophisticated electronic hardware, which can be expensive and, in the event of deterioration in the control circuitry, may become unreliable due to weakened control logic.

[0005] To overcome at least some of the aforementioned challenges, a hydraulic suspension system is provided. In one example, the hydraulic system includes a first manifold comprising a piston-side interface and a rod-side interface. The piston-side interface and the rod-side interface are fluidly connected to a piston chamber and a rod chamber in each of a first hydraulic cylinder and a second hydraulic cylinder, respectively. In this system, the manifold includes a first electrically activated valve fluidly connected to the piston-side interfaces of the first and second hydraulic cylinders. The manifold also includes a first damping device and a second damping device. Further in this system, the first electrically activated valve is configured to lock and unlock the vertical movement of the first and second hydraulic cylinders. In this system, when the vertical movement of the first and second hydraulic cylinders is locked, fluid communication between the first and second hydraulic cylinders is allowed via the first electrically activated valve to allow free rolling movement in the hydraulic suspension system. In this way, the first electrically activated valve, arranged between the hydraulic cylinders and the damping devices, allows suspension rolling movement to occur even when the vertical movement of both cylinders is locked. In this way, a situation where both rolling and vertical movement are locked, which could potentially reduce handling performance below a desired level, can be avoided if necessary.

[0006] In a further example, the hydraulic suspension system also includes multiple pilot-operated check valves fluidly connected to piston-side and rod-side interfaces. In such an example, the multiple pilot-operated check valves can be fluidly connected to a load-sensing (LS) component via a second electrically activated valve. Arranging the pilot-operated check valves in this way allows for locking and unlocking of suspension roll motion during the desired system operation period. For example, suspension roll motion can be allowed when the vertical movement of the first and second hydraulic cylinders is locked. Suspension roll motion can also be allowed when the system's leveling functions (e.g., cylinder position and / or pressure adjustment) are activated. In this way, fluid can flow to both cylinders during leveling operations. Therefore, the stiffness and position of the cylinders can be more balanced relative to each other if needed, which can enable the vehicle to achieve desired handling characteristics.

[0007] It should be understood that the above overview is provided to present a simplified version of the selection of concepts further described in the detailed description. This does not imply the identification of key or essential features of the claimed subject matter, the scope of which is uniquely defined by the appended claims. Furthermore, the claimed subject matter is not limited to embodiments that address any of the shortcomings pointed out above or in any part of this disclosure. Attached Figure Description

[0008] Figure 1 A schematic diagram of a vehicle including a first embodiment of a hydraulic suspension system with a first manifold and a second manifold is shown.

[0009] Figure 2 It shows Figure 1 A detailed view of the first manifold of the hydraulic suspension system depicted in the image.

[0010] Figure 3 A second embodiment of a hydraulic suspension system with multiple manifolds is shown.

[0011] Figure 4 A method for operating a hydraulic suspension system is shown.

[0012] Figure 5 A third embodiment of a hydraulic suspension system with multiple manifolds is shown.

[0013] Figure 6 It shows the representation Figure 2 The table describes the use case operation modes of the first manifold. Detailed Implementation

[0014] This paper describes a hydraulic suspension system with a modular manifold. This manifold allows the hydraulic suspension system to passively avoid undesirable system control variations if needed. For example, the hydraulic suspension system can be designed to lock the vertical movement of two hydraulic cylinders, preventing a situation where one cylinder is locked while the other is unlocked. In this way, a decrease in handling performance due to mismatched locking / unlocking conditions of the two hydraulic cylinders can be avoided. This vertical locking function can be achieved by using a valve that is fluidly connected to the piston chambers of both the hydraulic cylinders and multiple associated damping devices. Furthermore, in one example, the hydraulic suspension system can be designed to prevent rolling motion locking between the two hydraulic cylinders when the vertical movement of the hydraulic cylinders is locked. In this way, a firmly locked state in the system, i.e., where both rolling and vertical movements are locked, can be avoided if needed. Therefore, a decrease in handling performance due to a firmly locked state can be avoided.

[0015] The hydraulic system can be further designed to prevent rolling motion lock-up when the system's leveling functions (e.g., cylinder position and / or stiffness adjustment) are activated. Furthermore, in some embodiments, suspension rolling motion can be designed to be passively locked, allowing individual movement of the hydraulic cylinders. This passive locking of the hydraulic cylinders enables the hydraulic suspension system to achieve the desired higher-speed handling characteristics. The aforementioned rolling motion characteristics can be achieved via multiple pilot-operated check valves arranged between two hydraulic cylinders. These pilot-operated check valves can be closed and opened to lock and unlock the rolling motion, respectively. The pilot-operated check valves can be fluidly connected to a second electrically activated valve, which can be fluidly connected to a load sensing (LS) line. Certain aspects of suspension rolling motion and vertical lock-up management can be passively deployed using pilot-operated check valves in the system. Therefore, certain combinations of operating variables can be passively enabled, while others can be avoided, using a smart hydraulic circuit structure to at least partially meet the system control objectives. In this way, the suspension system can achieve the desired control variables using an efficient hydraulic circuit structure, while reducing the complexity of the system's programmed control if necessary.

[0016] Figure 1 A hydraulic suspension system in a vehicle is described, which includes a leveling manifold and manifolds for controlling axle rolling motion and cylinder vertical motion. Figure 2 A detailed view of a first embodiment of a manifold designed with rolling motion and vertical motion locking and unlocking functions is shown. Figure 3 A second embodiment of a manifold with adjustable axle rolling motion and vertical cylinder motion is described. Figure 4 A method for operating a suspension system is shown. Figure 5 A third embodiment of a manifold for controlling rolling and vertical motion is shown. Figure 6A table showing the operation matrices related to the locking and unlocking configurations of the suspension system's rolling and vertical motions is presented.

[0017] Figure 1 A vehicle 100 with a hydraulic suspension system 102 is shown. In one example, vehicle 100 may be an agricultural or industrial vehicle. In other examples, the vehicle may be a light, medium, or heavy commercial vehicle, passenger car, etc. In some cases, agricultural and industrial vehicles may experience a wider range of load and / or speed variations during use, and may therefore be particularly well-suited to utilizing the performance gains from the kinematic adjustability of the hydraulic suspension system described herein. However, other vehicles may also exhibit similar improvements in suspension performance, and therefore, hydraulic suspension systems may be applicable across a variety of vehicle platforms to achieve target kinematic characteristics.

[0018] If needed, the hydraulic suspension system 102 can be designed with modular component groups to facilitate the expansion of the hydraulic suspension system's functionality and adaptability. Therefore, the suspension platform can be deployed on a wider range of vehicles, which could further increase the platform's customer appeal.

[0019] The hydraulic suspension system 102 may include a leveling manifold 104. The hydraulic suspension system 102 may also include a manifold 106 (e.g., a center manifold) designed to manage suspension rolling motion (e.g., axle rolling motion) and / or hydraulic cylinder vertical locking operation. Suspension rolling motion can be a side-to-side angular movement of the suspension system, and particularly the axle, relative to a horizontal axis or plane. The layout of the hydraulic components and the specific structure and function of the manifold components are described herein. Figure 2 Let me elaborate.

[0020] The leveling manifold 104 can be connected to the manifold 106 via LS line 108, line 110 (e.g., rod-side line), and line 112 (e.g., piston-side line). As described herein, connections between hydraulic lines, components, etc., can represent fluid connections between components, where fluid communication is established. Figure 1 as well as Figure 2 and Figure 3 The LS line 108 and other load sensing conduits shown are indicated by dashed lines. However, it is understood that the LS line and other hydraulic lines described herein serve as conduits for the working fluid of the system. Furthermore, as described herein, the lines may be hydraulic conduits that enclose hydraulic oil and provide fluid connections between the components to which they are attached.

[0021] The hydraulic suspension system 102 may further include a first damping device 114, a second damping device 116, a third damping device 118, and / or a fourth damping device 120. For example... Figure 1As shown, the potential boundaries of these devices are demarcated by double-lined dashed lines: leveling manifold 104; manifold 106; and damping devices 114, 116, 118, and 120. Therefore, the double-lined dashed lines themselves do not directly indicate hydraulic conduits. However, it is understood that in other embodiments, these devices may have different groups of components.

[0022] Each of the damping devices 114, 116, 118, and 120 may be fluidly connected to the accumulator 122 via a conduit 124. The accumulator 122 may serve as a storage unit and may include a housing, internal chambers, etc. The first damping device 114 and the second damping device 116 may be fluidly connected to an electrically activated valve 126 in the manifold 106. The electrically activated valve 126 may be referred to as the first electrically activated valve. The second damping device 118 and the third damping device 120 may be fluidly connected to the rod chambers 128 and 130 in the first hydraulic cylinder 132 (e.g., the left cylinder) and the second hydraulic cylinder 134 (e.g., the right cylinder), respectively. It is understood that the first and second hydraulic cylinders may be associated with one of the axles (e.g., the front axle). The damping devices may be configured to regulate the vibration of the hydraulic cylinders.

[0023] The first hydraulic cylinder 132 may also include a piston chamber 136. The second hydraulic cylinder 134 may similarly include a piston chamber 138. The first hydraulic cylinder 132 and the second hydraulic cylinder 134 may each include a piston 140, a piston rod 142, a piston cylinder 144, etc., which allow for the implementation of height, stiffness, rolling motion, and / or vertical locking modes of the system. Therefore, hydraulic cylinders 132 and 134 can be in the form of double-acting hydraulic cylinders. This paper describes the control modes of the system.

[0024] Piston chamber 136 can be connected to manifold 106 via line 146, while rod chamber 128 can be connected to manifold via line 148. Therefore, manifold 106 may include a first rod-side interface 147 and a first piston-side interface 149. Similarly, piston chamber 138 can be connected to manifold 106 via line 150, while rod chamber 130 can be connected to manifold via line 152. Manifold 106 may also include a second rod-side interface 151 and a second piston-side interface 153. As described herein, piston-side chambers and rod-side chambers may respectively include a cavity, wall, valve, and / or other piston-side and rod-side components.

[0025] The first hydraulic cylinder 132 and the second hydraulic cylinder 134 can be mechanically coupled to a first vehicle component 154 (e.g., a vehicle axle) and a second vehicle component 156 (e.g., a vehicle chassis). Specifically, the first hydraulic cylinder 132 and the second hydraulic cylinder 134 can be mechanically coupled to the axle and the vehicle chassis at different locations (e.g., at laterally opposite sides of the vehicle). For example, the first hydraulic cylinder 132 can be mechanically coupled to a first suspension arm or other suitable axle component, while the second hydraulic cylinder 134 can be mechanically coupled to a second suspension arm or other suitable axle axle component. However, various axle interfaces have been envisioned. Specifically, in one embodiment, the axle can be included in a separate front suspension assembly 155. This separate front suspension assembly can include a pivot drive axle connected via a joint (e.g., a universal joint) to allow opposing wheels 157, 159 to be individually articulated under certain conditions. The separate front suspension assembly can include a differential and / or other conventional front suspension components.

[0026] In one embodiment, the axle can be a steerable axle, such as a front axle. In this way, the hydraulic suspension system can manage the vehicle's steering characteristics. However, in other examples, the first hydraulic cylinder 132 and the second hydraulic cylinder 134 may be mechanically coupled to the rear axle. The relative position between the first vehicle component and the second vehicle component may be referred to as the suspension position (e.g., suspension height). The distance between the first vehicle component 154 and the second vehicle component 156, determined by the hydraulic cylinders, is denoted as 158. In position adjustment mode, this distance can be lengthened or shortened to change the suspension height. For example, the cylinder height can be adjusted taking into account the vehicle's weight distribution. Changes in the system's suspension height can facilitate various aspects of vehicle operation, such as handling, material loading / unloading operations, etc.

[0027] The leveling manifolds 104 and 106, and the damping devices 114, 116, 118, and 120 can have a modular design, which allows the manifolds to be effectively integrated into the vehicle system. This modularity of components can further allow the system to be reconfigured and / or include additional modules to meet the target end-use design objectives of a specific vehicle platform, if needed. In this way, the adaptability of the suspension system can be extended, thereby increasing customer appeal.

[0028] The leveling manifold 104 may be connected to the storage tank 160, the load sensing (LS) component 162 (e.g., an compensator), and / or the pump 164 or other suitable pressure source. A tank line 166 may extend between the storage tank 160 and the leveling manifold 104, providing a fluid connection therebetween. A load sensing line 168 may extend between the LS component 162 and the leveling manifold 104, while a pump line 170 may extend between the pump 164 and the leveling manifold. It will be understood that in other embodiments, additional components may be located between the storage tank, the LS component, and / or the pump and the leveling manifold.

[0029] Tank 160 can be used as a storage unit for the system's working fluid. The system's working fluid is a suitable hydraulic fluid, such as oil (e.g., natural and / or synthetic oil). Therefore, tank 160 may include a housing enclosing the system's working fluid. Pump 164 can be designed to deliver pressurized fluid to leveling manifold 104. For example, the pump may be a variable displacement pump (e.g., an axial piston pump). However, other suitable types of pumps, such as axial flow pumps, centrifugal pumps, pumps with pressure vessels, etc., are also considered. LS component 162 can be coupled to pump 164. Therefore, LS component 162 and pump 164 can work together to regulate pump output based on load-sensing pressure. For example, when a threshold pressure is reached, the LS component (e.g., a pressure compensator) can constrain higher operating pressures (e.g., upper limit operating pressure) by reducing the pump's displacement (e.g., reducing the pump's displacement to a lower value, such as essentially zero). Therefore, the LS component can be used as a pump control device. Leveling manifold 104 may include multiple electrically activated valves. These valves may include a first valve 171, a second valve 172, a third valve 173, and / or a fourth valve 174. The first valve 171 may be a three-way / two-position (3 / 2) valve with three hydraulic ports and two positions. The third valve 173 may also be a 3 / 2 type valve (three-way / two-position valve). The second valve 172 may be a 2 / 2 type valve (two-way / two-position valve), and the fourth valve 174 may also be a 2 / 2 type valve (two-way / two-position valve). However, other valve configurations have been envisioned. The leveling manifold 104 may also include a pressure compensator 175 designed to manage supply pressure associated with load sensing. The leveling manifold 104 may also include a pressure relief valve 176 that bypasses the first valve 171 and the second valve 172, and a pressure relief valve 177 that bypasses the third valve 173 and the fourth valve 174.

[0030] The leveling manifold 104 may also include a plurality of orifices 178 designed to manage and set the leveling function speed. Specifically, the orifices 178 can determine the rate of adjustment of the suspension stiffness and position. The orifice size can be adjusted based on the end-use objective. Therefore, the orifices may include housings with internal profiles for restricting flow. The leveling manifold may also include a reciprocating valve 179, which allows the LS component 162 to see higher pressures in the inter-valve line.

[0031] Vehicle 100 may also include a control system 180 with a controller 182, actuators 184, and sensors 186. The controller 182 may encompass the control unit of the pump 164 discussed above. Therefore, the controller 182, and more generally the control system 180, may encompass one or more physical devices that may be located together and / or remotely for implementing hydraulic system control strategies. The controller 182 may receive signals from sensors 186 located at various locations in the suspension system 102 and vehicle 100. These sensors may include a pressure sensor 187 connected to a line in the leveling manifold 104, a position sensor 188 connected to hydraulic cylinders 132, 134, a temperature sensor 189, a vehicle speed sensor 190, a vehicle load sensor 191, etc.

[0032] The controller 182 can send control signals to actuators 184 located at different positions in the suspension system 102 and the vehicle 100. For example, the controller 182 can send signals to actuators in the leveling manifold 104, such as actuators of components in the leveling manifold (e.g., valves 171, 172, 173, 174), actuators of components in the manifold 106, actuators of components in the damping devices 114, 116, 118, 120, etc. For example, the controller 182 can send control signals to actuators in valves to open or close valves. Therefore, other controllable components in the suspension system can similarly function in terms of command signals and actuator adjustment.

[0033] In one example, controller 182 may include suitable circuitry for performing sensing and control functions, such as memory 192 and processor 193. In such an example, the memory of controller 182 may hold instructions stored therein, which, when executed by processor 193, cause the controller to perform the various methods, control techniques, etc., described herein. Processor 193 may include a microprocessor unit and / or other types of circuitry. Memory 192 may include known data storage media, such as random access memory, read-only memory, keep-alive memory, combinations thereof, etc. However, the controller may include additional or alternative circuitry to execute the sensing and control strategies described herein.

[0034] Controller 182 can be connected to input device 194 (e.g., a console dashboard, touch interface, touch panel, keyboard, or a combination thereof). Input device 194 can generate requests in response to driver input, such as adjusting suspension stiffness and / or position, triggering cylinder movement locking / unlocking, triggering suspension roll movement locking / unlocking, etc. However, in other examples, the above control operations can be automatically adjusted based on vehicle operating conditions.

[0035] The control system 180 can operate the leveling manifold 104 in different modes, enabling individual adjustment of the position and stiffness of the hydraulic cylinders 132 and 134. Specifically, in position adjustment mode, the leveling manifold 104 can deliver fluid to the piston chambers of the hydraulic cylinders 132 and 134 to lengthen the suspension (e.g., increase the height of the chassis (e.g., the front chassis)) while substantially maintaining a preset target pressure in the rod chambers (slightly venting the rod chambers). Furthermore, in position adjustment mode, the leveling manifold can vent fluid from the piston chambers of the hydraulic cylinders to retract the suspension itself (e.g., lower the vehicle chassis) while substantially maintaining a preset target pressure in the rod chambers (e.g., slightly pressurizing the rod chambers). In pressure adjustment mode, if needed, the leveling manifold can pressurize the piston chambers and rod chambers of the hydraulic cylinders to increase suspension stiffness without significantly altering the axle position. Additionally, in pressure adjustment mode, the leveling manifold can vent the piston chambers and rod chambers of the hydraulic cylinders to decrease suspension stiffness without significantly altering the axle position. In this way, the operational functionality of the suspension system is expanded, allowing for a corresponding increase in the system's degrees of freedom. Therefore, if needed, the system's suspension height and stiffness can be finely adjusted at different times to more appropriately adapt to at least some of the vehicle's operating conditions. The control system can be further designed to control the suspension's rolling motion and vertical cylinder movement, as detailed here.

[0036] exist Figure 1 as well as Figure 2 , Figure 3 and Figure 5 The coordinate system 199 is provided for reference. In one example, the z-axis can be a vertical axis, the x-axis can be a horizontal axis (e.g., a horizontal axis), and / or the y-axis can be a vertical axis. However, in other examples, the axes can have other orientations.

[0037] Figure 2Detailed illustrations of manifold 106 (e.g., center manifold), damping devices 114, 116, 118, 120, and accumulator 122 are shown. The damping devices 114, 116, 118, 120 can be configured to manage proportional damping between lower (e.g., minimum) and higher (e.g., maximum) values ​​based on transient conditions. Lower values ​​may occur when the proportional valve is closed (e.g., fully closed), and higher values ​​may occur when the proportional valve is open (e.g., fully open). In one example, when the vehicle is braking or accelerating, the damping can be increased (e.g., maximized) to perform the opposite dive / lift function. Continuing with such an example, the damping on the right and left sides can be managed separately to improve the vehicle's handling performance during high-speed cornering (e.g., maximizing the damping of the valve on the outer cornering side). Thus, in this example, the damping valve can be managed to improve longitudinal and lateral vehicle dynamics. Therefore, the vehicle's handling performance may be improved, thereby increasing customer appeal and satisfaction.

[0038] In one embodiment, each of the damping devices 114, 116, 118, and 120 may have similar components. For example, each of the damping devices may include an electrically activated valve 200 (e.g., a proportional valve), a check valve 202 connected in parallel with the electrically activated valve, a first orifice 204 located in line 206, and / or a second orifice 208 located in line 210 arranged parallel to lines 212 and 206. However, other arrangements of the damping devices have been contemplated. Furthermore, in other embodiments, the construction of the damping devices may differ, which may increase the complexity of the system.

[0039] Figure 2 The same is also shown in Figure 1 The diagram shows the LS line 108, rod-side line 110, and piston-side line 112 connecting the connecting manifold 106 to the leveling manifold 104. Damping devices 114 and 116 are shown connected to the electrically activated valve 126 via lines 214 and 216, respectively. The electrically activated valve 126 may be a 4 / 2 type valve (four-way / two-position) with four hydraulic ports and two positions. The four hydraulic ports provide fluid communication between the valve 126 and the first damping device 114, the second damping device 116, the piston chamber 136, and the piston chamber 138. However, in other embodiments, the valve 126 may have other suitable configurations.

[0040] In the open position, the electrically activated valve 126 allows flow between the first damping device 114 and the piston chamber 136 via conduit 218, and allows flow between the second damping device 116 and the piston chamber 138 via conduit 220. However, in the open position, cross-flow between the piston chambers via the valve may be blocked.

[0041] Conversely, in the closed position, the electrically activated valve 126 can form a bridging connection (e.g., an H-bridge connection) between lines 218 and 220. Thus, in the example of the H-bridge connection, a cross conduit extends between the two lines connecting the piston chambers to their respective dampers. The bridging connection allows the system to exhibit free rolling motion in the suspension without being affected by multiple check valves in the manifold, which prevents a firmly locked-in condition (a condition where both vertical and rolling motion are locked in the system) if needed. Furthermore, in the bridging connection, flow between piston chamber 136 and the first damping device 114 is restricted. Additionally, flow between piston chamber 138 and the second damping device 116 is restricted in the bridging connection. Specifically, the accumulator side of the H-bridge connection may be particularly restricted. The restriction in the bridging connection in valve 126 allows for pressure stabilization of piston chambers 136 and 138 after transients occurring between the piston chambers and the multiple accumulators connected to the first and second damping devices. In this way, when valve 126 is closed, the oscillating motion in the system can be reduced. The electrically activated valve 126 can be designed to close in response to energization and open in response to de-energization. Therefore, the valve's open configuration may be passive.

[0042] Opening the electrically activated valve 126 places the hydraulic system in an unlocked state, allowing vertical movement of the cylinders. In the unlocked state, vertical suspension movement of hydraulic cylinders 132 and 134 is permitted. Conversely, closing the electrically activated valve 126 places the hydraulic system in a locked state, allowing vertical movement of the cylinders. In the event of valve deterioration, the valve is designed to open upon de-energization to prevent suspension locking.

[0043] Figure 2 The diagram shows a first hydraulic cylinder 132 with a piston chamber 136 and a rod chamber 128, and a second hydraulic cylinder 134 with a piston chamber 138 and a rod chamber 130. Figure 2 The diagram also shows pipelines 146 and 148 connecting the rod chamber 128 and piston chamber 136 of the first hydraulic cylinder 132. Figure 2 The diagram also shows lines 150 and 152 connecting to the piston chamber 138 and rod chamber 130 of the second hydraulic cylinder 134. Each of lines 146, 148, 150, and 152 can be connected to a first pilot-operated check valve 222, a second pilot-operated check valve 224, a third pilot-operated check valve 226, and a fourth pilot-operated check valve 228, respectively. A guide line 230 can connect the first check valve 222 to the second check valve 224. A guide line 232 can connect the third check valve 226 to the fourth check valve 228. Figure 2The junction 234 shown represents a fluid junction between two pipelines that facilitates fluid communication between them. This junction designation is also used in other figures described herein.

[0044] Manifold 106 may also include electrically activated valves 236 and 238. Electrically activated valve 236 may be a VNO type valve, and electrically activated valve 238 may be a VCN type valve. However, other suitable valve types have been considered. Electrically activated valve 236 may be referred to as a second electrically activated valve, and valve 238 may be referred to as a third electrically activated valve, or vice versa. It can be further understood that valves 236 and 238 may be referred to as pilot control valves.

[0045] Manifold 106 may also include a first orifice 240 and / or a second orifice 242 in line 243. Manifold 106 may also include a third orifice 244 and a fourth orifice 246 in line 247, residing in a conduit 247. These orifices restrict flow through the lines to which they are attached and may include housings containing flow restrictors. Line 243 may be arranged parallel to line 248 where the first pilot-operated check valve 222 and the second pilot-operated check valve 224 are located. Similarly, line 247 may be arranged parallel to line 250 where the third pilot-operated check valve 226 and the fourth pilot-operated check valve 228 are located. Positioning the orifices parallel to the pilot-operated check valves allows for pressure stability between opposing (e.g., left and right) cylinder piston chambers, thereby reducing the chance of cylinder pressure variations exceeding target levels. To elaborate, placing the orifice in parallel with the pilot-operated check valve provides pressure stability after the moment of rolling when the rolling motion is locked, which prevents cylinder pressure changes from exceeding the desired level after several rolling motions.

[0046] The design of pilot-operated check valves 222, 224, 226, and 228 allows for locking and unlocking of the rolling motion when needed. Specifically, when pilot-operated check valves 222, 224, 226, and 228 are closed, the suspension rolling motion is locked. Conversely, when the pilot-operated check valves are open, the suspension rolling motion is unlocked.

[0047] To manage the state of the pilot-operated check valve, a higher pressure between the piston and rod chambers of hydraulic cylinders 132 and 134 can be used to supply hydraulic fluid to the pilot line via the electrically activated valve 238. Line 250 connects the pilot-operated check valve to the electrically activated valve 238.

[0048] Manifold 106 may also include a reciprocating valve 253 having a line 252 extending between lines 248 and 250. The reciprocating valve 253 allows valve 238 to see higher pressures in lines 248 and 250. However, in other embodiments, the reciprocating valve 253 may be omitted from manifold 106. Figure 5 An embodiment of a manifold 500 with valve 502 (e.g., a 4 / 2 type valve), valve 504, and valve 506 is shown. These and other components in the manifold 500 may have the same characteristics as those specified in the diagram. Figures 1-2 The manifold 106 shown has a similar structure and functional characteristics. Therefore, for the sake of brevity, redundant descriptions have been omitted. However, Figure 5 The manifold 500 shown replaces the reciprocating valve with a check valve 508 in line 510 connecting to valve 506. This modification to manifold 500 allows for more forceful pressurization using line 512 during leveling operations, unaffected by the operation of valves 504 and 506.

[0049] Back Figure 2 In one embodiment, the electrically activated valve 238 can close when de-energized to allow the rolling motion to be passively locked. When the suspension rolling motion is passively locked, the first hydraulic cylinder 132 and the second hydraulic cylinder 134 can move independently. This rolling motion can be passively locked during higher-speed vehicle operation to improve vehicle handling performance. The electrically activated valve 236 can open when de-energized, allowing the guide line to be connected to... Figure 1 The LS line 108 of the tank 160 shown is discharged. To lock the suspension rolling motion, two valves 236, 238 can be energized via a common command to pressurize the guide lines 230, 232 of check valves 222, 224, 226, 228.

[0050] To allow the rolling motion to not lock during activation of the leveling operation, the electrically activated valve 236 can be connected to the LS line 108, which is guided to the leveling manifold 104, such as... Figure 1As shown. Connecting valve 236 to LS line 108 allows the LS line to pressurize pilot lines 230 and 232 for check valves 222, 224, 226, and 228 during leveling manifold operation. Therefore, if needed, the pilot-operated check valves can be pilot-operated to continuously supply fluid to both hydraulic cylinders during leveling operation, unaffected by the control states of electrically activated valves 236 and 238. In this way, the rolling motion can be passively unlocked to achieve the desired handling characteristics and, if possible, avoid the situation where the rolling motion is unlocked while the vertical motion is locked. Specifically, when the leveling operation is activated and the pilot-operated check valves are unlocked, cylinder leveling can be balanced. Therefore, the system can achieve substantially symmetrical leveling, which avoids the situation where one valve deteriorates and only one cylinder is allowed to move. In this way, the vehicle's handling performance is improved. Orifices 240, 242, 244, and 246 allow for pressure balancing between the left and right cylinders after a short period of time. Furthermore, in some embodiments, when vertical motion is locked, the orifices integrated into valve 126 can provide a relatively slow pressure balancing between the accumulator and the piston.

[0051] Furthermore, in one example, in Figure 1 The line 108, depicted connecting manifold 106 to leveling manifold 104, can be used, for example, to drain working fluid from accumulator 122 during maintenance. The control system can perform the accumulator draining operation by energizing electrically activated valve 238 to open it. Furthermore, during the accumulator draining operation, the control system can close other valves in manifold 106 and / or leveling manifold 104. Due to the valves in the manifold being arranged as described above, working fluid will flow from the accumulator to tank 160 via valves 171 and / or 174 of line 108, such as... Figure 1 As shown. Therefore, LS line 108 can serve as a venting route during maintenance. In this way, the efficiency of system maintenance and / or repair can be improved.

[0052] In another embodiment, valves 236 and 238 can be replaced with 3 / 2 type valves, but the functions of the aforementioned valves 236 and 238 can be retained. However, using two valves 236 and 238 (e.g., 2 / 2 type valves) can reduce the possibility of fluid leakage from line 108 that could cause a reduction in suspension height.

[0053] Figure 3 A second embodiment of a hydraulic suspension system 300 is shown, which may include a leveling manifold 302, damping devices 304, 306, 308, an accumulator 310, hydraulic cylinders 312, 314, a reservoir 320, an LS component 322, a pump 324, and a control system 326. The aforementioned components may have the same characteristics as... Figure 1 and Figure 2The corresponding components in the suspension system 102 shown have similar structures and functions.

[0054] The suspension system 300 may also include a manifold 316 with a modified arrangement. Figure 3 The suspension system 300 shown is Figure 1 and Figure 2 Compared to the suspension system 102 shown, it has one less rod-side damping device. However, systems with fewer than three or more than four damping devices have been considered. Figure 3 The manifold 316 depicted in the diagram omits the two pilot-operated check valves connecting to the rod chambers of hydraulic cylinders 312 and 314. In this way, fluid communication between the rod chambers of the hydraulic cylinders can persist during different modal control strategies. Figure 1 and Figure 2 Compared to the suspension system 102 shown, the suspension system 300 can achieve similar functions regarding locking / unlocking of rolling and vertical movements. For example, the suspension system 300, particularly the manifold 316, can be configured to lock and unlock the vertical movement of the cylinders and the rolling movement of the axle. However, due to... Figure 1 and Figure 2 Because the suspension system 102 depicted has fewer damping devices, the suspension system 300 may have a slightly smaller range of actuator force controllability during instantaneous conditions.

[0055] refer to Figure 4 This illustrates a method 400 for operating a hydraulic suspension system. This method 400 can be performed via the above-described method... Figures 1-3 and / or Figure 5 The method 400 may be implemented using one or more vehicles, hydraulic suspension systems, and system components. However, in other examples, the method 400 may be implemented using other suitable vehicles, hydraulic suspension systems, and / or system components. Furthermore, in one embodiment, the method 400 may be stored as instructions executable by a processor of a controller, such as... Figure 1 The controller 182 is depicted in the figure. However, in other embodiments, suitable control circuitry of an additional or alternative type may be used.

[0056] At 402, the method includes: determining operating conditions. Operating conditions may include vehicle speed, vehicle load, ambient temperature, suspension cylinder position, suspension cylinder stiffness, input device position, etc. These conditions can be determined from sensor input signals and / or modeling.

[0057] At point 404, the method determines whether to transition to a mode where the vertical suspension movement of the cylinder is locked or to a mode where the vertical suspension movement of the cylinder is unlocked. This determination can take into account system operating conditions, such as vehicle speed, vehicle load, operator-activated input device configuration, etc. Specifically, in one example, the vehicle operator can lock and unlock the vertical suspension movement based on their judgment and working conditions, such as locking and unlocking. Alternatively, the controller can be designed to disengage the vertical suspension movement when the vehicle exceeds a predetermined speed to improve vehicle handling. For example, when the vehicle operator is attaching attachments to a front crane or working with a front loader, they can lock the vertical suspension movement. Conversely, when the operator drives the vehicle on a road or field exceeding a threshold speed (e.g., 5 km / h, 6 km / h, 10 km / h, etc.), the vertical suspension movement can be automatically unlocked to improve vehicle handling. As previously mentioned, the design of the 4 / 2 valve in the center manifold of the hydraulic system allows (e.g., ensures) rolling motion when vertical locking is possible to reduce the chance of the system exhibiting a decrease in handling performance.

[0058] If it is determined that neither mode transition is desirable, then the method moves to 406. At 406, the method includes maintaining the current operating strategy of the suspension system. For example, the system can continue to operate in either vertical locking or vertical unlocking mode.

[0059] However, if it is determined that a transition to a vertical locking mode is desired, the method proceeds to 408. At 408, the method includes transitioning the suspension system to a vertical locking mode. Transitioning the system to a vertical locking mode at 410 includes closing a 4 / 2 type electrically activated valve in the manifold by energizing the valve. In the closed position, the 4 / 2 valve bridging connection allows fluid to flow between the first and second piston chambers and restricts fluid flow from the first and second hydraulic cylinders to the first and second damping devices. The bridging connection in the valve allows rolling motion locking to be prevented while vertical locking is activated. In this way, the vehicle can exhibit targeted handling characteristics. Although the electrically activated valve in method 400 is described as a 4 / 2 type valve, other configurations of electrically activated valves are also contemplated.

[0060] If it is determined that a transition to the vertical unlocking mode is required, the method continues to 412. At 412, the method includes: transitioning to the vertical unlocking mode. The transition to the vertical unlocking mode at 414 includes: opening the 4 / 2 electrically activated valve in the center manifold by de-energizing the valve. In the open position, fluid flow between the two hydraulic cylinders and the associated accumulator's opposing piston chambers is permitted, while bridging flow between the opposing piston chambers via the valve is prohibited. In this way, the system can exhibit vertical suspension movement. In the vertical unlocking mode, suspension rolling movement can be locked and unlocked based on the vehicle's operating conditions. For example, rolling movement can be unlocked during leveling. In detail, suspension rolling movement can be unlocked in response to the locking vertical movement of the first and second hydraulic cylinders by the operation of a valve coupled to a pilot-operated check valve in the center manifold. For example, coupled to a pilot-operated check valve (e.g. Figure 2 The electrically activated valves (shown as valves 236 and 238) can be energized in conjunction to pilot-open these check valves and allow suspension roll movement. In one example, these electrically activated valves can be energized via a common command signal. In this way, the system's command logic can be simplified. Conversely, the electrically activated valves connected to the pilot-operated check valves can be de-energized to close the check valves and lock the roll movement. In this way, suspension roll movement can be locked and unlocked at opportune times, allowing the vehicle to achieve desired handling characteristics and avoiding handling characteristics that might degrade handling performance. In one example, the method may also include opening the connection to the LS line (e.g., Figure 2 The electrically activated valve (e.g., for pipeline 108) shown Figure 2 The valve 238 shown is used to simultaneously close other valves in the system (e.g., valves 236, 126, and / or valves in the leveling manifold) to discharge fluid from the accumulator. As previously mentioned, when the valves are arranged in this manner, the accumulator can be drained, for example, during maintenance. Therefore, the LS line can serve as a drain path during maintenance. In this way, the system can be maintained more efficiently.

[0061] Figure 6 An exemplary table 600 is depicted, which in one embodiment lists the hydraulic suspension system (e.g., ...) as an operating mode matrix. Figures 1-2The rolling motion control variables and vertical motion control variables in the hydraulic suspension system 102 shown herein are related to each other. As described herein, this is an example and does not represent any kind of preference, but rather represents one of many possible aspects of the systems and methods described herein. Line 602 indicates an operational configuration that allows rolling motion in the system. When rolling motion is allowed, the left and right hydraulic cylinders allow side-to-side angular movement of the suspension system (e.g., an axle). Line 604 indicates an operational configuration that controls rolling motion in the system. For example, controlling rolling motion may include substantially preventing rolling motion or limiting rolling motion to a desired range. Column 606 indicates an operational configuration of the system in which vertical motion is locked, and column 608 indicates a system in which suspension is activated (allowing vertical motion of suspension to occur (e.g., movement of springs and / or dampers)). As shown, when the system allows rolling motion, vertical motion can be locked, or vertical suspension motion can be allowed. However, when rolling motion is controlled, the hydraulic machinery of the system allows (e.g., guarantees): preventing the locking of vertical motion of the system. Therefore, when rolling motion is controlled, only vertical suspension motion can be allowed. In this way, situations that could degrade vehicle handling performance can be avoided.

[0062] The technical advantage of the hydraulic suspension system and method described herein is that it reduces (e.g., avoids) the possibility of handling performance deteriorating below desired levels by preventing a situation where one or two hydraulic cylinders are locked while the others are unlocked. Another technical advantage of the system and method described herein is that it allows suspension roll motion to be unlocked, which permits fluid flow to these two hydraulic cylinders when the system's leveling function is activated. If necessary, allowing fluid flow to these two cylinders allows for a more balanced stiffness and position of these cylinders, thereby improving vehicle handling performance.

[0063] Figures 1-3 and Figure 5Example configurations with the relative positioning of various components are shown. If shown as being in direct contact or directly connected to each other, then in at least one example, such elements may be referred to as being in direct contact or directly connected, respectively. Similarly, in at least one example, elements shown as being continuous or adjacent to each other may be continuous or adjacent to each other, respectively. As an example, components placed in coplanar contact with each other may be referred to as being in coplanar contact. As another example, in at least one example, elements positioned spaced apart from each other, with only a gap between them and no other components, may be so referred to. As yet another example, elements shown above / below each other, on opposite sides of each other, or to the left / right of each other may be so referred to relative to each other. Furthermore, as shown in the figures, in at least one example, the topmost element or the position of the element may be referred to as the “top” of the component, and the bottommost element or the position of the element may be referred to as the “bottom” of the component. As used herein, top / bottom, upper / lower, above / below may be relative to the vertical axis of the figures and are used to describe the positioning of the elements in the figures relative to each other. Thus, in one example, an element shown above other elements is vertically positioned above the other elements. As yet another example, the shape of an element depicted in the accompanying drawings may be described as having such a shape (e.g., such as circular, straight, planar, curved, rounded, chamfered, angled, etc.). Furthermore, in one example, elements coaxial with each other may be so described. Additionally, in at least one example, elements shown intersecting each other may be described as intersecting elements or intersecting with each other. Further still, in one example, an element shown inside or outside another element may be so described. In other examples, elements offset from each other may be so described. As used herein, unless otherwise specified, the term "substantially" is interpreted as indicating a range of plus or minus five percent.

[0064] The invention will be further described in the following paragraphs. In one aspect, a hydraulic suspension system is provided, comprising: a first manifold, the first manifold including a piston-side interface and a rod-side interface fluidly connected to a piston chamber and a rod chamber, respectively, for each of a first hydraulic cylinder and a second hydraulic cylinder; wherein the first manifold includes: a first electrically activated valve fluidly connected to the piston-side interface, a first damping device, and a second damping device; wherein the first electrically activated valve is configured to lock and unlock vertical movement of the first and second hydraulic cylinders; and wherein, when the vertical movement of the first and second hydraulic cylinders is locked, the first electrically activated valve allows fluid communication between the first and second hydraulic cylinders to allow free rolling movement in the hydraulic suspension system.

[0065] In another aspect, a method for operating a hydraulic suspension system is provided, the method comprising: locking vertical movement of a first hydraulic cylinder and a second hydraulic cylinder by closing a first electrically activated valve located in a first manifold and fluidly coupled to a first piston chamber of a first hydraulic cylinder and a second piston chamber of a second hydraulic cylinder; wherein, in the closed position, the first electrically activated valve allows fluid to flow between the first and second piston chambers and restricts fluid flow from the first and second hydraulic cylinders to a first damping device and a second damping device, respectively. In one example, the method may further comprise unlocking vertical movement of the first and second hydraulic cylinders by opening the first electrically activated valve. In another example, the method may further comprise unlocking suspension rolling movement by closing a second electrically activated valve coupled to a plurality of pilot-operated check valves and a load sensing (LS) line. Furthermore, in one example, the method may further comprise opening a load sensing line coupled to the first manifold while closing the first electrically activated valve to discharge fluid from one or more accumulators in the hydraulic suspension system.

[0066] In another aspect, a hydraulic suspension system is provided, comprising a manifold fluidly connected to a piston chamber and a rod chamber of each of a first hydraulic cylinder and a second hydraulic cylinder; wherein the manifold includes: a first electrically activated valve fluidly connected to the piston chambers of the first and second hydraulic cylinders, and a first damping device and a second damping device; and a controller configured to: in a first operating condition, lock the vertical movement of the first and second cylinders by closing the first electrically activated valve; wherein fluid communication between the first and second hydraulic cylinders is permitted when the vertical movement of the first and second hydraulic cylinders is locked.

[0067] In any aspect or combination of these aspects, the first electrically activated valve can be closed by energizing it.

[0068] In any aspect or combination of these aspects, energizing the first electrically activated valve can close the first electrically activated valve to lock vertical movement, and de-energizing the first electrically activated valve can open the first electrically activated valve to unlock vertical movement.

[0069] In any aspect or combination of these aspects, closing the first electrically activated valve can activate the bridging connection, and the bridging connection can fluidly connect the piston chambers of the first and second hydraulic cylinders, and can restrict fluid flow from the piston chambers to the first and second damping devices.

[0070] In any aspect or combination of these aspects, the bridging connection can be configured to: allow free rolling motion in the suspension system unaffected by the multiple check valves in the first manifold; and stabilize the pressure in the piston chambers of the first and second hydraulic cylinders after transients occurring between the piston chambers of the first and second hydraulic cylinders and the multiple accumulators fluidly connected to the first and second damping devices.

[0071] In any aspect or combination of these aspects, when the vertical movement in the first and second hydraulic cylinders is unlocked by the first electrically activated valve, the first damping device can be fluidly connected to the first hydraulic cylinder, and the second damping device can be fluidly connected to the second hydraulic cylinder.

[0072] In any aspect or combination of these aspects, the hydraulic suspension system may also include: a plurality of pilot-operated check valves fluidly connected to piston-side and rod-side interfaces of the first manifold.

[0073] In any aspect or combination of these aspects, multiple pilot-operated check valves can be fluidly connected to the LS component via a second electrically activated valve.

[0074] In any aspect or combination of these aspects, the hydraulic suspension system may further include: a leveling manifold fluidly connected to the first manifold, wherein when a leveling operation is activated in the leveling manifold, a plurality of pilot-operated check valves can unlock suspension rolling motion to balance cylinder leveling, unaffected by the state of at least one electrically activated pilot control valve in the first manifold.

[0075] In any aspect or combination of these aspects, the first and second hydraulic cylinders can be fluidly coupled to a separate front suspension assembly.

[0076] In any aspect or combination of these aspects, the first electrically activated valve can be closed by energizing it.

[0077] In any aspect or combination of these aspects, the second electrically activated valve can be closed by energizing it.

[0078] In any aspect or combination of these aspects, the second electrically activated valve can be closed by energizing it.

[0079] In any aspect or combination of these aspects, the suspension rolling motion can be unlocked in response to the vertical movement of the locking first and second hydraulic cylinders.

[0080] In any aspect or combination of these aspects, in response to initiating a leveling operation in a leveling manifold fluidly connected to the first manifold, suspension rolling motion can be unlocked.

[0081] In any aspect or combination of these aspects, the controller can be configured to unlock the vertical movement of the first and second cylinders by opening the first electrically activated valve.

[0082] In any aspect or combination of these aspects, the hydraulic suspension system may further include: a plurality of pilot-operated check valves connected to the piston chambers of the first hydraulic cylinder and the second hydraulic cylinder, and the rod chambers of the first hydraulic cylinder and the second hydraulic cylinder; wherein the plurality of pilot-operated check valves may be connected to a load sensing (LS) line via a second electrically activated valve; and wherein the controller may be configured to unlock suspension rolling motion by closing the second electrically activated valve.

[0083] In any aspect or combination of these aspects, when the first electrically activated valve is closed and locks the vertical movement of the first and second hydraulic cylinders, the first electrically activated valve can connect the first damping device to the second damping device via a bridging connection; and after transients occur between the piston chambers of the first and second hydraulic cylinders and the plurality of accumulators fluidly connected to the first and second damping devices, the bridging connection can stabilize the pressure in the piston chambers of the first and second hydraulic cylinders.

[0084] In any aspect or combination of these aspects, the hydraulic suspension system may further include: a leveling manifold connected to the first manifold via a tank line and a pressure source line, wherein the leveling manifold may include a plurality of valves configured to individually regulate the pressure in the first and second hydraulic cylinders, unaffected by the position adjustment of the first and second hydraulic cylinders.

[0085] In another embodiment, a separate suspension arrangement in a vehicle is provided, the suspension arrangement including a center manifold comprising a valve selectively fluidly connected to the piston side and rod side of each of a pair of double-acting hydraulic cylinders; wherein the valve operates in a locked state, in which the valve directs fluid between the pair of double-acting hydraulic cylinders; and wherein the valve operates in an unlocked state, in which the valve directs fluid between the pair of double-acting hydraulic cylinders and a pair of accumulators.

[0086] Although various embodiments have been described above, it should be understood that they are presented as examples and not as limitations. It will be apparent to those skilled in the art that the disclosed subject matter can be implemented in other specific forms without departing from the spirit of the subject matter. Therefore, the above embodiments are to be considered illustrative rather than restrictive in all respects.

[0087] It should be noted that the example control and estimation routines included herein can be used with various suspension system configurations. The control methods and routines disclosed herein can be stored as executable instructions in non-transitory memory and can be executed by a control system including controllers integrated with various sensors, actuators, and other vehicle hardware. Furthermore, certain parts of the methods can be taken as physical actions to change the state of the device. The specific routines described herein can represent one or more of any number of processing strategies. Thus, the various actions, operations, and / or functions shown can be performed in the shown order, in parallel, or in some cases omitted. Similarly, the processing order for implementing the features and advantages of the exemplary examples described herein is not necessary but provided for ease of illustration and description. Depending on the specific strategy used, one or more of the shown actions, operations, and / or functions can be repeatedly performed. Furthermore, the described actions, operations, and / or functions can be graphically represented as code to be programmed into a computer-readable storage medium in non-transitory memory of a vehicle control system, wherein the described actions are performed by executing instructions in a system including various hardware components and integrated with electronic controllers. One or more method steps described herein may be omitted if necessary.

[0088] It is understood that the constructions and routines disclosed herein are exemplary in nature, and these specific examples should not be considered limiting, as many variations are possible. For example, the above-described techniques can be applied to hydraulic suspension systems with different constructions, as well as to vehicles with various propulsion sources, such as electric motors, engines, combinations thereof, etc. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and constructions disclosed herein, as well as other features, functions, and / or characteristics.

[0089] The appended claims specifically point to certain combinations and sub-combinations that are considered novel and non-obvious. These claims may relate to an element or a first element or its equivalent. Such claims should be understood to include combinations of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and / or characteristics may be claimed in this application or related applications by amending these claims or by filing new claims. Such claims, whether broader, narrower, identical, or different in scope from the original claims, are considered to be included within the scope of this disclosure.

Claims

1. A hydraulic suspension system, the hydraulic suspension system comprising: The first manifold, for each of the first hydraulic cylinder and the second hydraulic cylinder, includes a piston-side interface and a rod-side interface respectively fluidly connected to the piston chamber and the rod chamber. The first manifold includes: A first electrically activated valve, a first damping device, and a second damping device are fluidly connected to the piston-side interface; Wherein, the first electrically activated valve is configured to lock and unlock the vertical movement of the first hydraulic cylinder and the second hydraulic cylinder; and When the vertical movement of the first hydraulic cylinder and the second hydraulic cylinder is locked, the first electrically activated valve allows fluid communication between the first hydraulic cylinder and the second hydraulic cylinder to allow free rolling movement in the hydraulic suspension system.

2. The hydraulic suspension system according to claim 1, characterized in that, Energize the first electrically activated valve to close it and lock the vertical movement, and de-energize the first electrically activated valve to open it and unlock the vertical movement.

3. The hydraulic suspension system according to claim 2, characterized in that, The first electrically activated valve is closed to activate the bridging connection, wherein the bridging connection fluidly connects the piston chambers of the first hydraulic cylinder and the second hydraulic cylinder and restricts fluid flow from the piston chambers to the first damping device and the second damping device.

4. The hydraulic suspension system according to claim 3, characterized in that, The bridging connection is configured as follows: This allows free rolling motion in the suspension system to be unaffected by the multiple check valves in the first manifold; as well as After transients occur between the piston chambers of the first and second hydraulic cylinders and the plurality of accumulators fluidly connected to the first and second damping devices, the pressure in the piston chambers of the first and second hydraulic cylinders is stabilized.

5. The hydraulic suspension system according to claim 1, characterized in that, When the vertical movement in the first hydraulic cylinder and the second hydraulic cylinder is unlocked by the first electrically activated valve, the first damping device is fluidly connected to the first hydraulic cylinder, and the second damping device is fluidly connected to the second hydraulic cylinder.

6. The hydraulic suspension system according to claim 1, characterized in that, Also includes: Multiple pilot-operated check valves are fluidly connected to the piston-side and rod-side interfaces of the first manifold.

7. The hydraulic suspension system according to claim 6, characterized in that, The plurality of pilot-operated check valves are fluidly connected to the load sensing (LS) component via a second electrically activated valve.

8. The hydraulic suspension system according to claim 6, characterized in that, Also includes: fluids A leveling manifold is connected to the first manifold, wherein when the leveling operation in the leveling manifold is activated, the plurality of pilot-operated check valves unlock the suspension rolling motion to balance the cylinder leveling, unaffected by the state of at least one electrically activated pilot control valve in the first manifold.

9. The hydraulic suspension system according to claim 1, characterized in that, The first hydraulic cylinder and the second hydraulic cylinder are fluidly connected to a separate front suspension assembly.

10. The hydraulic suspension system according to claim 1, characterized in that, Also includes: The controller is configured to: In the first operating condition, the vertical movement of the first hydraulic cylinder and the second hydraulic cylinder is locked by closing the first electrically activated valve; When the vertical movement of the first hydraulic cylinder and the second hydraulic cylinder is locked, fluid communication between the first hydraulic cylinder and the second hydraulic cylinder is permitted.

11. The hydraulic suspension system according to claim 10, characterized in that, The controller is configured such that: The vertical movement of the first hydraulic cylinder and the second hydraulic cylinder is unlocked by opening the first electrically activated valve.

12. The hydraulic suspension system according to claim 10, characterized in that, Also includes: Multiple pilot-operated check valves are connected to the piston chambers of the first hydraulic cylinder and the second hydraulic cylinder, as well as the rod chambers of the first hydraulic cylinder and the second hydraulic cylinder. The plurality of pilot-operated check valves are connected to the load sensing (LS) line via a second electrically activated valve; and The controller is configured to unlock the suspension rolling motion by closing the second electrically activated valve.

13. The hydraulic suspension system according to claim 10, characterized in that: When the first electrically activated valve is closed and the vertical movement of the first hydraulic cylinder and the second hydraulic cylinder is locked, the first electrically activated valve connects the first damping device to the second damping device via a bridging connection. as well as The bridging connection stabilizes the pressure in the piston chambers of the first and second hydraulic cylinders after transients occur between the piston chambers of the first and second hydraulic cylinders and the plurality of accumulators fluidly connected to the first and second damping devices.

14. The hydraulic suspension system according to claim 10, characterized in that, The controller is configured such that: The suspension roll motion is unlocked by closing a second electrically activated valve connected to multiple pilot-operated check valves and load sensing (LS) lines.

15. The hydraulic suspension system according to claim 10, characterized in that, The controller is configured such that: While closing the first electrically activated valve, the load sensing line connected to the first manifold is opened to discharge fluid from one or more accumulators in the hydraulic suspension system. The suspension rolling motion is unlocked in response to the vertical movement of locking the first and second hydraulic cylinders; or Specifically, the suspension rolling motion is unlocked in response to initiating a leveling operation in a leveling manifold that is fluidly connected to the first manifold.

Images