Truck shock absorber and control method thereof

Abstract

The application discloses a truck shock absorber and a control method thereof, and relates to the field of vehicle suspensions; the truck shock absorber comprises an outer tube, an inner tube, a bottom valve assembly, a connecting rod, a piston valve assembly, an electromagnetic proportional valve, a position sensor, a speed sensor and a controller. The bottom valve assembly is provided with a basic damping oil path and a bypass throttling oil path, and the electromagnetic proportional valve is arranged in the bypass throttling oil path. The controller adjusts the opening degree of the electromagnetic proportional valve according to the position information and the motion speed information of the connecting rod, and when the connecting rod enters a buffer working area and the motion speed information reaches a preset speed threshold, the oil flow flowing through the bypass throttling oil path is reduced, and the oil flow flowing through the basic damping oil path is increased, so that a pre-limit position hydraulic damping area is formed before a mechanical compression limit position, and the impact of a bottom touch in a compression end section is reduced.

Description

Technical Field

[0001] This invention relates to the field of vehicle suspension, and in particular to a truck shock absorber and its control method. Background Technology

[0002] Truck shock absorbers are typically installed between the chassis and the axle to suppress vibrations generated during vehicle operation. Existing truck shock absorbers generally consist of an outer tube, an inner tube, a connecting rod, a piston valve assembly, and a bottom valve assembly. An oil reservoir is formed between the outer and inner tubes, while a working chamber is formed within the inner tube. The connecting rod drives the piston valve assembly to reciprocate within the working chamber. As the oil flows between the working chamber and the oil reservoir, it creates throttling resistance through the piston valve assembly and the bottom valve assembly, thereby generating compression damping and restoring damping.

[0003] Under normal driving conditions, the piston valve assembly and bottom valve assembly in existing shock absorbers can meet basic vibration reduction requirements. However, when a truck travels over potholes, is heavily loaded, or experiences a sudden upward impact on the wheels, the connecting rod may rapidly compress in the compression direction, approaching the mechanical compression limit. At this point, if the shock absorber continues to operate according to the normal oil flow pattern during the compression stroke, the oil discharge resistance between the working chamber and the oil reservoir may not increase in time. The piston valve assembly may still maintain a high speed at the end of the compression phase, causing the shock absorber to bear a large bottoming-out impact load when approaching the mechanical compression limit.

[0004] Existing shock absorber damping structures typically focus on damping matching during the normal compression and recovery strokes, making it difficult to proactively adjust the hydraulic discharge resistance on the bottom valve side at the end of compression based on changes in the connecting rod's position relative to the inner tube and its speed. In other words, existing shock absorbers need to maintain a relatively smooth damping response during the normal stroke, while simultaneously requiring a timely increase in hydraulic resistance as the connecting rod approaches its mechanical compression limit at high speed—a conflicting requirement. Current technology lacks a truck shock absorber that can link connecting rod position and speed information with bottom valve side damping adjustment to create a pre-limited hydraulic damping zone before the mechanical compression limit. Summary of the Invention

[0005] The purpose of this invention is to provide a truck shock absorber that can actively adjust the flow cross-section of the bypass throttling oil circuit at the end of compression based on the position and speed information of the connecting rod. This reduces the flow rate of oil flowing through the bypass throttling oil circuit and increases the flow rate of oil flowing through the basic damping oil circuit, thereby forming a pre-limited hydraulic damping zone before the mechanical compression limit position. This achieves the advantages of smoothness of ordinary stroke damping, timely hydraulic protection at the end of compression, and reliable operation of the truck shock absorber.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A truck shock absorber includes an outer tube, an inner tube, a bottom valve assembly, a connecting rod, and a piston valve assembly. An oil reservoir is formed between the outer and inner tubes, and a working chamber is formed within the inner tube. The connecting rod is axially movable and passes through the working chamber, with the piston valve assembly located at its end facing the bottom valve assembly. The bottom valve assembly is located at the bottom end of the inner tube and connects the working chamber and the oil reservoir. The bottom valve assembly is provided with a basic damping oil passage and a bypass throttling oil passage connected in parallel between the working chamber and the oil reservoir; The truck shock absorber also includes a controller, as well as an electromagnetic proportional valve, a position sensor, and a speed sensor that are electrically connected to the controller; The electromagnetic proportional valve is located in the bypass throttling oil passage and is configured to adjust the flow cross-section of the bypass throttling oil passage. Position and speed sensors are mounted on the inner or outer tube and are used to collect the position and speed information of the connecting rod relative to the inner tube, respectively. The controller is used to determine whether the link has entered the buffer working area based on the position information, and to determine whether the link is in a compressed state moving toward the mechanical compression limit position based on the motion speed information. The controller is also used to generate a flow-limiting control signal in response to the linkage entering the buffer working area, being in a compressed state, and the motion speed information reaching a preset speed threshold. This reduces the opening of the electromagnetic proportional valve, decreases the flow rate of the oil flowing through the bypass throttling oil circuit, and increases the flow rate of the oil flowing through the basic damping oil circuit, so as to form a pre-limited hydraulic damping zone before the mechanical compression limit position.

[0007] Further settings: The buffer working area is determined based on the axial distance between the piston valve assembly and the bottom valve assembly; The mechanical compression limit position is the position of the connecting rod when the axial distance between the piston valve assembly and the bottom valve assembly reaches the preset minimum axial distance. The pre-limit hydraulic damping zone is located within the stroke range of the piston valve assembly before it reaches the mechanical compression limit position.

[0008] Further configuration: The bypass throttling oil circuit includes an oil inlet, an adjustable valve chamber, and an oil outlet; The oil inlet is connected to the working chamber; The oil outlet is connected to the oil storage chamber; The adjustable valve chamber is connected between the oil inlet and the oil outlet; The electromagnetic proportional valve is at least partially located within the adjustable valve chamber.

[0009] Further settings: The electromagnetic proportional valve is a normally open electromagnetic proportional valve. The normally open electromagnetic proportional valve maintains its normally open position when it does not receive a current limiting control signal from the controller. The normally open position is the preset initial position.

[0010] Another object of the present invention is to provide a control method for the above-mentioned truck shock absorber. Includes the following steps: S1. Obtain the position information of the connecting rod relative to the inner tube collected by the position sensor, and the motion speed information of the connecting rod relative to the inner tube collected by the speed sensor; S2. Determine whether the link has entered the buffer working area based on the position information; S3. In response to the connecting rod entering the buffer working area, being in a compressed state moving towards the mechanical compression limit position, and the motion speed information reaching the preset speed threshold, a flow limiting control signal is generated to reduce the opening of the electromagnetic proportional valve. S4. Reduce the opening of the electromagnetic proportional valve according to the flow limiting control signal to reduce the flow rate of oil flowing through the bypass throttling oil circuit and increase the flow rate of oil flowing through the basic damping oil circuit, forming a pre-limit hydraulic damping zone before the mechanical compression limit position. S2 includes the following sub-steps: S21. Determine the axial distance between the piston valve assembly and the bottom valve assembly based on the position information; S22. In response to the axial distance between the piston valve assembly and the bottom valve assembly being less than or equal to the preset buffer distance, determine that the connecting rod enters the buffer working area; Among them, the mechanical compression limit position is the position of the connecting rod when the axial distance between the piston valve assembly and the bottom valve assembly reaches the preset minimum axial distance, and the preset buffer distance is greater than the preset minimum axial distance. In S3, it is also determined whether the link is in a compressed state moving toward the mechanical compression limit position based on the motion speed information; In response to the linkage entering the buffer working area, being in a compressed state, and the motion speed information reaching a preset speed threshold, a current limiting control signal is generated.

[0011] Further settings: In S3, a current limiting control signal is generated based on the opening degree control relationship; The opening control relationship includes a control function with the axial distance and movement speed information between the piston valve assembly and the bottom valve assembly as independent variables and the target opening degree of the electromagnetic proportional valve as the dependent variable. The target opening degree is positively correlated with the axial distance between the piston valve assembly and the bottom valve assembly, and negatively correlated with the motion speed information.

[0012] Further configuration: In S3, a flow-limiting control signal is generated based on the axial distance between the piston valve assembly and the bottom valve assembly; In response to the axial distance between the piston valve assembly and the bottom valve assembly being greater than a preset intermediate distance and less than or equal to a preset buffer distance, a flow-limiting control signal characterizing the first small-rate flow is generated. In response to the axial distance between the piston valve assembly and the bottom valve assembly being less than or equal to a preset intermediate distance, a flow-limiting control signal characterizing the second closing rate is generated, wherein the second closing rate is greater than the first closing rate. In S4, when the opening of the electromagnetic proportional valve is reduced according to the current limiting control signal, the actual opening rate of the electromagnetic proportional valve is not greater than the preset maximum closing rate.

[0013] Further settings: Prior to S2, the following are also included: Receive collision prediction signals sent by external vehicle systems; In response to a collision prediction signal indicating a risk of a compressive impact that could cause the link to enter the buffer zone at a velocity greater than a preset impact velocity threshold, perform at least one of the following pre-adjustment operations: Increase the preset buffer distance; Lower the preset speed threshold.

[0014] Further settings: The electromagnetic proportional valve in the truck shock absorber has a reset structure that resets to a preset initial opening degree after power failure or a default opening degree holding mechanism. The preset initial opening degree is the opening degree of the electromagnetic proportional valve when no flow limiting control is performed. After S1 acquires the location and velocity information, it also includes: In response to the position sensor or speed sensor acquiring a signal that exceeds the preset valid signal range, is lost, or remains unchanged for a preset duration, the output of the control signal used to adjust the opening of the electromagnetic proportional valve is stopped, so that the electromagnetic proportional valve maintains the preset initial opening through the reset structure or the default opening holding mechanism.

[0015] Further settings: The preset initial opening degree is the opening degree of the electromagnetic proportional valve when no flow limiting control is performed; Following S4, it also includes: In response to the linkage exiting the buffer working area, or the motion speed information falling below the preset recovery speed threshold, a recovery control signal is generated to increase the opening of the electromagnetic proportional valve. The electromagnetic proportional valve is restored to the preset initial opening degree according to the recovery control signal; S22 includes: Use the preset buffer distance as the entry determination distance; When the axial distance between the piston valve assembly and the foot valve assembly is less than or equal to the entry determination distance, the connecting rod is determined to have entered the buffer working area. In response to the axial distance between the piston valve assembly and the bottom valve assembly being greater than the exit determination distance, it is determined that the connecting rod exits the buffer working area, and the exit determination distance is greater than the entry determination distance.

[0016] In summary, the present invention has the following beneficial effects: First, the truck shock absorber of the present invention, by setting a basic damping oil circuit and a bypass throttling oil circuit in the bottom valve assembly, and placing an electromagnetic proportional valve in the bypass throttling oil circuit, allows the oil exchange resistance between the working chamber and the oil reservoir to be adjusted according to the opening degree of the electromagnetic proportional valve. During normal stroke, the bypass throttling oil circuit can participate in the oil flow, keeping the oil exchange resistance at a low level, thereby maintaining the normal damping response of the shock absorber. When the connecting rod enters the buffer working area and the movement speed information reaches a preset speed threshold, the controller reduces the opening degree of the electromagnetic proportional valve, reducing the flow cross section of the bypass throttling oil circuit, thereby allowing more oil to flow through the basic damping oil circuit. Thus, this solution can form a pre-limited hydraulic damping zone before the mechanical compression limit position, reducing the bottoming impact generated when the connecting rod is pressed in at high speed.

[0017] Second, the buffer working area is determined based on the axial distance between the piston valve assembly and the bottom valve assembly, ensuring that the compression end protection directly corresponds to the position of the piston valve assembly relative to the bottom valve assembly. As the piston valve assembly gradually approaches the bottom valve assembly, the axial distance gradually decreases, allowing the controller to identify whether the connecting rod has entered the compression end risk zone based on this axial distance. The mechanical compression limit position is determined by the position of the connecting rod when the axial distance between the piston valve assembly and the bottom valve assembly reaches a preset minimum axial distance, allowing the pre-limit hydraulic damping zone to be positioned before the mechanical compression limit position. This ensures that hydraulic damping occurs before mechanical bottoming out, which helps reduce the impact load at the end of compression.

[0018] Third, the bypass throttling oil circuit includes an inlet, an adjustable valve chamber, and an outlet. The electromagnetic proportional valve is at least partially located within the adjustable valve chamber, allowing the effective flow area of ​​the bypass throttling oil circuit to be adjusted. When the electromagnetic proportional valve is a normally open type, it maintains a normally open opening when no flow-limiting control signal is received. This normally open opening serves as the preset initial opening, ensuring low flow resistance in the bypass throttling oil circuit during the normal stroke. When the controller outputs a flow-limiting control signal, the electromagnetic proportional valve changes from the preset initial opening to a smaller opening, increasing the oil discharge resistance on the bottom valve side. Thus, the smoothness of the normal stroke and the hydraulic protection capability at the end of the compression phase can be switched through the same bypass throttling oil circuit.

[0019] Fourth, the control method of this invention acquires position information and motion speed information, enabling the controller to simultaneously obtain the linkage's stroke state and impact intensity. Position information is used to determine whether the linkage is approaching its mechanical compression limit, while motion speed information characterizes the linkage's compression speed. Only when the linkage enters the buffer working zone, is in a compressed state, and the motion speed information reaches a preset speed threshold, does the controller generate a flow-limiting control signal to reduce the opening of the electromagnetic proportional valve, thereby avoiding triggering excessive damping simply because the position is close but the speed is low. This control logic reduces false triggering and ensures that the increased damping at the end of compression matches the actual impact risk.

[0020] Fifth, in the segmented control method of this invention, the controller can generate flow-limiting control signals with different closing rates based on the axial distance between the piston valve assembly and the bottom valve assembly. When the axial distance is greater than a preset intermediate distance and less than or equal to a preset buffer distance, the controller generates a flow-limiting control signal representing the first closing rate, causing the electromagnetic proportional valve to reduce its opening at a slower rate. When the axial distance is less than or equal to the preset intermediate distance, the controller generates a flow-limiting control signal representing the second closing rate, which is greater than the first closing rate. Therefore, the front section of the buffer working area can suppress damping abrupt changes, and the rear section of the buffer working area can enhance the anti-bottom-out capability.

[0021] Sixth, in the continuous control mode of this invention, the controller generates a flow-limiting control signal based on the opening control relationship, so that the target opening of the electromagnetic proportional valve is simultaneously affected by the axial distance and the movement speed information. The target opening is positively correlated with the axial distance between the piston valve assembly and the bottom valve assembly, and negatively correlated with the movement speed information. That is, the closer the piston valve assembly is to the bottom valve assembly, the smaller the target opening; the greater the connecting rod pressing speed, the smaller the target opening. This method enables the opening of the electromagnetic proportional valve to continuously change with the impact risk at the end of compression, improving the damping matching degree of the pre-limit hydraulic damping zone.

[0022] Seventh, when an external vehicle system sends a collision prediction signal, the controller can perform a pre-adjustment operation before S2. In response to the collision prediction signal indicating a risk of compression impact that could cause the connecting rod to enter the buffer zone at a speed exceeding a preset impact speed threshold, the controller can increase the preset buffer distance or decrease the preset speed threshold. Increasing the preset buffer distance allows the connecting rod to enter the buffer zone further from its mechanical compression limit; decreasing the preset speed threshold triggers the current limiting control signal at a lower compression speed. Thus, the shock absorber can enter a protective preparation state before a sudden impact occurs.

[0023] Eighth, sensor anomaly protection and recovery control can improve the stability of the control process. In response to the position sensor or speed sensor's acquired signal exceeding the preset effective signal range, being lost, or remaining unchanged for more than a preset time, the controller stops outputting the control signal used to adjust the opening of the electromagnetic proportional valve, allowing the electromagnetic proportional valve to maintain the preset initial opening through a reset structure or default opening holding mechanism. In response to the linkage exiting the buffer working area, or the motion speed information falling below the preset recovery speed threshold, the controller generates a recovery control signal, causing the electromagnetic proportional valve to return to the preset initial opening. By forming a hysteresis interval through the entry and exit judgment distances, and limiting the opening change rate through a preset maximum closing rate, frequent boundary switching and damping abrupt changes can be reduced. Attached Figure Description

[0024] Figure 1 A schematic diagram of the overall structure of a truck shock absorber; Figure 2 for Figure 1 A magnified view of a portion of point A in the middle; Figure 3 This is a block diagram of a truck shock absorber control system. Figure 4 Main flowchart of the control method for truck shock absorbers; Figure 5 Here is the flowchart for the S2 compression buffer working area determination sub-flow; Figure 6 This is a flowchart of the signal generation sub-process under S3 compression state.

[0025] In the diagram, 10 is the working chamber; 20 is the oil reservoir; 30 is the first lifting ring; 40 is the second lifting ring; 100 is the outer pipe; 200 is the inner pipe; 300 is the guide; 310 is the oil seal; 400 is the limit sleeve; 500 is the connecting rod; 600 is the piston valve assembly; 700 is the bottom valve assembly; 701 is the basic damping oil circuit; 702 is the bypass throttling oil circuit; 801 is the position sensor; 802 is the speed sensor; 900 is the electromagnetic proportional valve; 901 is the oil inlet; 902 is the oil outlet; and 903 is the adjustable valve chamber. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the accompanying drawings.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] Combination Figure 1 This embodiment provides a truck shock absorber, which includes an outer tube 100, an inner tube 200, a connecting rod 500, a piston valve assembly 600, and a bottom valve assembly 700. The outer tube 100 is sleeved outside the inner tube 200, forming an oil reservoir 20 between the outer tube 100 and the inner tube 200, and a working chamber 10 is formed inside the inner tube 200. The connecting rod 500 passes axially through the inner tube 200 into the working chamber 10, with one end connected to a first lifting ring 30 and the other end extending toward the bottom valve assembly 700 and connecting to the piston valve assembly 600. A second lifting ring 40 is disposed at the end of the outer tube 100 near the bottom valve assembly 700 for connection to the vehicle mounting part.

[0029] During vehicle operation, connecting rod 500 drives piston valve assembly 600 to reciprocate within working chamber 10. During the compression stroke, connecting rod 500 is pressed towards bottom valve assembly 700, and piston valve assembly 600 moves towards bottom valve assembly 700. Oil in working chamber 10 near bottom valve assembly 700 is discharged into oil reservoir 20 via bottom valve assembly 700. Bottom valve assembly 700 creates throttling resistance to oil discharge, thereby generating compression damping.

[0030] Combination Figure 1 and Figure 2 The bottom valve assembly 700 is located at the bottom end of the inner tube 200 and connects the working chamber 10 and the oil reservoir 20. The bottom valve assembly 700 has a basic damping oil passage 701 and a bypass throttling oil passage 702, which are connected in parallel between the working chamber 10 and the oil reservoir 20. The basic damping oil passage 701 provides basic throttling resistance. The bypass throttling oil passage 702 provides an adjustable discharge path.

[0031] The bypass throttling oil passage 702 includes an inlet 901, an adjustable valve chamber 903, and an outlet 902. The inlet 901 communicates with the working chamber 10, the outlet 902 communicates with the oil storage chamber 20, and the adjustable valve chamber 903 is connected between the inlet 901 and the outlet 902. An electromagnetic proportional valve 900 is at least partially disposed within the adjustable valve chamber 903. The electromagnetic proportional valve 900 adjusts the flow cross-section of the bypass throttling oil passage 702 by changing the valve core position or the valve opening.

[0032] In some embodiments, the bottom valve assembly 700 may include a valve seat, a valve plate assembly, and a throttling orifice structure. The basic damping oil passage 701 may be formed by the main throttling orifice in the valve seat, the opening and closing gap between the valve plate assembly and the valve seat, and the main flow channel connecting the working chamber 10 and the oil reservoir 20. The bypass throttling oil passage 702 may be formed by a bypass channel in the valve seat that is arranged in parallel with the basic damping oil passage 701. The bypass channel sequentially forms an oil inlet 901, an adjustable valve chamber 903, and an oil outlet 902 along the oil flow direction.

[0033] During normal operation, the electromagnetic proportional valve 900 maintains a preset initial opening, allowing the bypass throttling oil passage 702 to have a large flow cross-section. Oil can flow simultaneously between the working chamber 10 and the oil reservoir 20 via both the basic damping oil passage 701 and the bypass throttling oil passage 702. At this time, the bypass throttling oil passage 702 shares part of the oil flow, resulting in lower overall oil exchange resistance in the bottom valve assembly 700, which helps maintain smooth damping under normal driving conditions.

[0034] When the connecting rod 500 approaches its mechanical compression limit and its speed is high, the controller reduces the opening of the electromagnetic proportional valve 900, thus reducing the flow cross-section of the bypass throttling oil passage 702. At this time, the flow resistance of the bypass throttling oil passage 702 increases, and the flow rate of the oil flowing through it decreases accordingly. As the connecting rod 500 and piston valve assembly 600 continue to move towards the bottom valve assembly 700, forcing the oil in the working chamber 10 to be discharged into the oil reservoir 20 via the bottom valve assembly 700, the pressure difference across the bottom valve assembly 700 increases, thereby increasing the flow rate of the oil flowing through the basic damping oil passage 701. Consequently, the oil discharge resistance between the working chamber 10 and the oil reservoir 20 increases, forming a pre-limit hydraulic damping zone before the mechanical compression limit position.

[0035] In some embodiments, the electromagnetic proportional valve 900 is a normally open electromagnetic proportional valve. The normally open electromagnetic proportional valve maintains its normally open opening when it does not receive a flow-limiting control signal from the controller. This normally open opening can serve as a preset initial opening, allowing the bypass throttling oil passage 702 to maintain low flow resistance during its normal stroke. When the controller outputs a flow-limiting control signal, the normally open electromagnetic proportional valve reduces its opening according to the signal, thereby increasing the flow resistance of the bypass throttling oil passage 702.

[0036] Combination Figure 1 and Figure 3 The truck shock absorber also includes a position sensor 801, a speed sensor 802, and a controller. The position sensor 801 is mounted on the inner tube 200 or the outer tube 100 and is used to collect position information of the connecting rod 500 relative to the inner tube 200. The speed sensor 802 is mounted on the inner tube 200 or the outer tube 100 and is used to collect speed information of the connecting rod 500 relative to the inner tube 200. The position sensor 801 and the speed sensor 802 can be arranged close to the extended end of the connecting rod 500 to improve the accuracy of identifying position changes in the final compression stage of the connecting rod 500.

[0037] The controller is electrically connected to position sensor 801, speed sensor 802, and electromagnetic proportional valve 900. After receiving position and speed information, the controller determines whether link 500 has entered the buffer working area based on the position information. When link 500 enters the buffer working area and the speed reaches a preset speed threshold, a current limiting control signal is generated. The current limiting control signal acts on electromagnetic proportional valve 900 via the electromagnetic proportional valve drive circuit, causing the opening of electromagnetic proportional valve 900 to decrease.

[0038] In some embodiments, the position sensor 801 may be a linear displacement sensor, a magnetostrictive displacement sensor, a Hall effect displacement sensor, or an eddy current displacement sensor, used to output a position electrical signal corresponding to the axial position of the connecting rod 500. The speed sensor 802 may be a magnetoelectric speed sensor or a Hall effect speed sensor, used to output a speed electrical signal corresponding to the movement speed of the connecting rod 500. The speed sensor 802 may also include a speed detection circuit, which calculates the movement speed information based on the continuously sampled position information. The controller determines whether the connecting rod 500 is close to the mechanical compression limit position based on the position information, and determines the impact intensity of the connecting rod 500 at the end of the compression stage based on the movement speed information, thereby avoiding false triggering of current limiting control simply because the position is close but the speed is low.

[0039] Combination Figure 1 In some embodiments, the truck shock absorber also includes a guide 300. The guide 300 is located on the side of the inner tube 200 near the extended end of the connecting rod 500, and guides the axial movement of the connecting rod 500. An oil seal 310 may also be provided between the guide 300 and the connecting rod 500 to reduce oil leakage from the working chamber 10 along the extended position of the connecting rod 500. A limiting sleeve 400 may also be provided on the connecting rod 500, which moves synchronously with the connecting rod 500 to assist in the assembly positioning or normal stroke limitation of the shock absorber.

[0040] The buffer working zone at the end of compression is determined based on the axial distance between the piston valve assembly 600 and the bottom valve assembly 700. As the connecting rod 500 moves along the compression direction, the piston valve assembly 600 moves synchronously towards the bottom valve assembly 700, and the axial distance between them gradually decreases. When this axial distance is less than or equal to a preset buffer distance, the controller determines that the connecting rod 500 has entered the buffer working zone. When the axial distance between the piston valve assembly 600 and the bottom valve assembly 700 reaches a preset minimum axial distance, the connecting rod 500 reaches its mechanical compression limit position. The pre-limit hydraulic damping zone is located within the stroke range before the piston valve assembly 600 reaches its mechanical compression limit position; therefore, hydraulic damping occurs before mechanical bottoming out.

[0041] Combination Figure 3 Position sensor 801 inputs the position information of link 500 to the controller, and speed sensor 802 inputs the movement speed information of link 500 to the controller. External vehicle systems can input collision prediction signals to the controller, which indicate potential compression impact conditions. Collision prediction signals can originate from the body controller, axle acceleration sensors, active safety controllers, or vehicle chassis domain controllers. The controller retrieves stored parameters and calibration data based on the received information.

[0042] The parameter storage and calibration data may include preset speed threshold, preset impact speed threshold, preset buffer distance, preset intermediate distance, entry judgment distance, exit judgment distance, preset recovery speed threshold, and preset maximum closing rate. The preset intermediate distance is less than the preset buffer distance and is greater than zero. The preset minimum axial distance is less than the preset intermediate distance. The preset effective signal range may correspond to the displacement voltage range of position sensor 801, the speed voltage range of speed sensor 802, or the speed pulse frequency range.

[0043] In some embodiments, the preset buffer distance, preset intermediate distance, preset speed threshold, preset recovery speed threshold, and preset maximum closing rate can be calibrated through bench tests or vehicle road tests. During calibration, the mechanical compression limit position corresponding to the axial distance between the piston valve assembly 600 and the bottom valve assembly 700 reaching the preset minimum axial distance can be determined first. Then, the preset buffer distance and preset intermediate distance can be determined based on the remaining stroke of the connecting rod 500 at the end of compression. The preset speed threshold and preset recovery speed threshold can also be determined based on the speed distribution of the connecting rod 500 under conditions of potholes, heavy load driving, and sudden upward impact. The preset maximum closing rate can be determined based on the response speed of the electromagnetic proportional valve 900 and the allowable damping change range, ensuring that changes in the opening degree of the electromagnetic proportional valve 900 do not cause excessive damping abrupt changes.

[0044] For example, in a calibration scenario, the preset buffer distance can be set to 30mm, the preset intermediate distance to 12mm, the preset minimum axial distance to 5mm, the entry judgment distance to 30mm, the exit judgment distance to 35mm, the preset speed threshold to 0.8m / s, the preset recovery speed threshold to 0.3m / s, and the preset impact speed threshold to 1.2m / s. These values ​​illustrate the relationship between the parameters; actual values ​​can be recalibrated based on shock absorber specifications, vehicle weight, suspension travel, and road impact conditions.

[0045] Combination Figure 4 The control method in this embodiment can be executed cyclically according to a control cycle. Before S2, the controller can also execute a collision pre-adjustment process. The collision pre-adjustment process includes receiving a collision prediction signal sent by an external vehicle system, and performing at least one pre-adjustment operation when the collision prediction signal indicates a risk of compression impact. The pre-adjustment operation includes at least one of increasing a preset buffer distance and decreasing a preset speed threshold.

[0046] When the collision prediction signal indicates that the connecting rod 500 is expected to enter the buffer working zone at a speed greater than the preset impact speed threshold, the controller determines that there is a risk of compression impact. Increasing the preset buffer distance allows the connecting rod 500 to be identified as entering the buffer working zone at a position further away from its mechanical compression limit. Decreasing the preset speed threshold allows a lower compression speed to trigger the current limiting control signal. Through these pre-adjustment operations, the shock absorber can enter a protective preparation state before the impact arrives.

[0047] Combination Figure 4 Then, S1 is executed to acquire the position information of the connecting rod 500 relative to the inner tube 200 collected by the position sensor 801, and the movement speed information of the connecting rod 500 relative to the inner tube 200 collected by the speed sensor 802. S2 is executed to determine whether the connecting rod 500 has entered the buffer working area based on the position information. S3 is executed to generate a flow-limiting control signal to reduce the opening of the electromagnetic proportional valve 900 in response to the connecting rod 500 entering the buffer working area and the movement speed information reaching a preset speed threshold. S4 is executed to reduce the opening of the electromagnetic proportional valve 900 according to the flow-limiting control signal, so as to reduce the flow rate of oil flowing through the bypass throttling oil circuit 702 and increase the flow rate of oil flowing through the basic damping oil circuit 701, forming a pre-limited hydraulic damping zone before the mechanical compression limit position.

[0048] Combination Figure 5 After acquiring position and speed information in S1, and before determining the buffer working area in S2, the controller first checks whether the sensor signal is abnormal or lost. Abnormal sensor signals include the acquired signal exceeding the preset valid signal range, loss of signal, or remaining unchanged for more than a preset duration. If any of these abnormalities occur, the controller stops outputting the control signal used to adjust the opening of the electromagnetic proportional valve 900, causing the electromagnetic proportional valve 900 to maintain the preset initial opening through a reset structure that resets it to the preset initial opening or a default opening holding mechanism. This abnormality protection process can prevent incorrect position or speed information from causing the electromagnetic proportional valve 900 to close abnormally.

[0049] Combination Figure 5 Step S2 includes sub-steps S21 and S22. S21 determines the axial distance between the piston valve assembly 600 and the bottom valve assembly 700 based on position information. S22 determines that the connecting rod 500 has entered the buffer working area in response to the axial distance between the piston valve assembly 600 and the bottom valve assembly 700 being less than or equal to a preset buffer distance. In S22, the preset buffer distance can be used as the entry determination distance, and the connecting rod 500 is determined to have entered the buffer working area when the axial distance is less than or equal to the entry determination distance.

[0050] Furthermore, S22 includes entry and exit determination. When the axial distance between the piston valve assembly 600 and the foot valve assembly 700 is less than or equal to the entry determination distance, the controller determines that the connecting rod 500 has entered the buffer working area. When the axial distance between the piston valve assembly 600 and the foot valve assembly 700 is greater than the exit determination distance, the controller determines that the connecting rod 500 has exited the buffer working area. The exit determination distance being greater than the entry determination distance prevents frequent triggering of entry and exit state switching when the connecting rod 500 oscillates near the boundary of the buffer working area. If the axial distance is greater than the entry determination distance but less than or equal to the exit determination distance, the controller maintains the determination state of the previous control cycle.

[0051] In another embodiment, the controller can also calculate the remaining compression stroke based on the absolute displacement of the connecting rod 500 relative to the inner tube 200 and a pre-calibrated mechanical compression limit position. The remaining compression stroke is the distance between the current position of the connecting rod 500 and the mechanical compression limit position. When the remaining compression stroke is less than or equal to a preset buffer distance, the controller determines that the connecting rod 500 has entered the buffer working area. This embodiment does not require direct calculation of the axial distance between the piston valve assembly 600 and the foot valve assembly 700; as long as the difference between the current position of the connecting rod 500 and the mechanical compression limit position can be determined, the buffer working area determination can be completed.

[0052] Combination Figure 6 Upon entering S3, the controller first determines whether the connecting rod 500 is in a compressed state, moving towards its mechanical compression limit, based on the motion speed information, and then determines whether the motion speed information has reached a preset speed threshold. If the connecting rod 500 is not in a compressed state, or the motion speed information has not reached the preset speed threshold, the controller does not generate a new flow-limiting control signal. If the motion speed information is lower than the preset speed threshold but not lower than the preset recovery speed threshold, the controller can maintain the target opening of the previous control cycle until the recovery condition is met. If the connecting rod 500 is in a compressed state and the motion speed information has reached the preset speed threshold, the controller generates a flow-limiting control signal based on the axial distance between the piston valve assembly 600 and the bottom valve assembly 700.

[0053] Combination Figure 6In a segmented control method, the controller divides the buffer working area into a first control interval and a second control interval. The first control interval corresponds to the interval where the axial distance between the piston valve assembly 600 and the bottom valve assembly 700 is greater than a preset intermediate distance but less than or equal to a preset buffer distance. The second control interval corresponds to the interval where the axial distance between the piston valve assembly 600 and the bottom valve assembly 700 is less than or equal to a preset intermediate distance. When the connecting rod 500 is in the first control interval, the controller generates a flow-limiting control signal characterizing the first closing rate, causing the electromagnetic proportional valve 900 to reduce its opening at a slower rate. When the connecting rod 500 is in the second control interval, the controller generates a flow-limiting control signal characterizing the second closing rate, which is greater than the first closing rate, causing the electromagnetic proportional valve 900 to reduce its opening faster when it is closer to the mechanical compression limit position.

[0054] In another continuous control mode, the controller generates a flow-limiting control signal based on the opening control relationship. The opening control relationship comprises a control function with the axial distance and speed between the piston valve assembly 600 and the bottom valve assembly 700 as independent variables, and the target opening of the electromagnetic proportional valve 900 as the dependent variable. The target opening is positively correlated with the axial distance between the piston valve assembly 600 and the bottom valve assembly 700, and negatively correlated with the speed. That is, the closer the piston valve assembly 600 is to the bottom valve assembly 700, the smaller the target opening; the greater the pressing speed of the connecting rod 500, the smaller the target opening.

[0055] In one lower-level implementation, the target opening degree According to the formula Confirmed. Among them, The target opening degree for the electromagnetic proportional valve 900. To preset the initial opening, and All are expressed as percentage openings; This is the speed information, in m / s. The axial distance between the piston valve assembly 600 and the foot valve assembly 700 is in mm. This is the speed calibration coefficient, expressed in % / (m / s), used to convert motion speed information into a percentage opening correction amount; This is a distance calibration factor, expressed as % / mm, used to convert axial distance into a percentage opening correction. Target opening. It is limited to between the minimum opening degree and the preset initial opening degree to prevent the electromagnetic proportional valve 900 from closing too much or exceeding the allowable opening range.

[0056] In another lower-level implementation, the opening control relationship can be implemented using a two-dimensional calibration table. The two-dimensional calibration table uses axial distance intervals and speed intervals as indices, storing the corresponding target opening degree under each index combination. When the axial distance interval indicates that the piston valve assembly 600 is closer to the foot valve assembly 700, or the speed interval indicates that the connecting rod 500 has a greater pressing speed, the corresponding target opening degree in the two-dimensional calibration table is smaller. Regardless of whether a segmented control method or a continuous control method is used, it is used to generate a flow-limiting control signal that reduces the opening degree of the electromagnetic proportional valve 900.

[0057] During execution of S4, the controller reduces the opening of the electromagnetic proportional valve 900 according to the current limiting control signal. To avoid abrupt changes in damping caused by rapid changes in opening, the controller can limit the actual rate of change of the electromagnetic proportional valve 900 opening to no greater than the preset maximum closing rate. In this way, the opening of the electromagnetic proportional valve 900 will not decrease dramatically instantaneously due to the current limiting control signal in a single control cycle, and the process of distributing oil from the bypass throttling oil circuit 702 to the basic damping oil circuit 701 is more stable.

[0058] In another embodiment, the controller can generate a closed-loop drive current based on the difference between the target opening and the current opening, causing the electromagnetic proportional valve 900 to approach the target opening cycle by cycle, and maintain the target opening after reaching it. Alternatively, the controller can decrease the opening of the electromagnetic proportional valve 900 cycle by cycle with a fixed step size until the electromagnetic proportional valve 900 reaches the target opening or the minimum permissible opening. Both the closed-loop control method and the fixed-step control method described above are used to reduce the opening of the electromagnetic proportional valve 900 according to the current-limiting control signal.

[0059] When the opening of the electromagnetic proportional valve 900 decreases, the effective flow area within the adjustable valve chamber 903 decreases, and the flow resistance of the bypass throttling oil passage 702 increases. As the connecting rod 500 and piston valve assembly 600 continue to move towards the bottom valve assembly 700, forcing the oil in the working chamber 10 to be discharged into the oil reservoir 20 via the bottom valve assembly 700, the pressure difference across the bottom valve assembly 700 increases with the increase in resistance of the bypass throttling oil passage 702. After the pressure difference across the bottom valve assembly 700 increases, some of the oil that was originally discharged through the bypass throttling oil passage 702 is diverted to the basic damping oil passage 701, and the flow rate of the oil flowing through the basic damping oil passage 701 increases accordingly. Because the basic damping oil passage 701 has a relatively high throttling resistance, the oil discharge resistance on the bottom valve side increases, thereby forming a pre-limit hydraulic damping zone before the connecting rod 500 approaches the mechanical compression limit position.

[0060] Combination Figure 4Following S4, the controller continues to determine whether the connecting rod 500 has exited the buffer working area or whether the motion speed information is lower than the preset recovery speed threshold. If the connecting rod 500 has exited the buffer working area or the motion speed information is lower than the preset recovery speed threshold, it indicates that the risk of impact at the end of compression has been eliminated or reduced. At this time, the controller generates a recovery control signal and, based on the recovery control signal, restores the electromagnetic proportional valve 900 to the preset initial opening. After the electromagnetic proportional valve 900 returns to the preset initial opening, the bypass throttling oil circuit 702 regains a large flow cross-section, and the shock absorber returns to the damping response state under normal stroke. If the connecting rod 500 has not exited the buffer working area and the motion speed information is still not lower than the preset recovery speed threshold, the controller ends the current control cycle and continues monitoring in the next control cycle.

[0061] Through the aforementioned structure and control method, this embodiment enables the truck shock absorber to maintain a low damping response under normal driving conditions. When the connecting rod 500 enters the buffer working zone at high speed, it actively reduces the flow cross-section of the bypass throttling oil circuit 702, decreasing the oil flow rate through the bypass throttling oil circuit 702 and increasing the oil flow rate through the basic damping oil circuit 701, thereby prematurely forming a pre-limit hydraulic damping zone. This pre-limit hydraulic damping zone is located before the mechanical compression limit position, absorbing some of the compression kinetic energy before the mechanical bottoming out, reducing the bottoming-out impact at the end of compression, and improving the reliability of the truck shock absorber under conditions of potholes, heavy load driving, and sudden upward impact.

[0062] The above embodiments are merely explanations of the present invention and are not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to these embodiments without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A truck shock absorber, comprising an outer tube (100), an inner tube (200), a bottom valve assembly (700), a connecting rod (500), and a piston valve assembly (600), wherein an oil reservoir (20) is formed between the outer tube (100) and the inner tube (200), and a working chamber (10) is formed inside the inner tube (200), the connecting rod (500) is axially movable and passes through the working chamber (10), and a piston valve assembly (600) is provided at the end facing the bottom valve assembly (700); the bottom valve assembly (700) is located at the bottom end of the inner tube (200) and connects the working chamber (10) and the oil reservoir (20), characterized in that: The bottom valve assembly (700) is provided with a basic damping oil passage (701) and a bypass throttling oil passage (702) connected in parallel between the working chamber (10) and the oil reservoir (20). The truck shock absorber also includes a controller, as well as an electromagnetic proportional valve (900), a position sensor (801), and a speed sensor (802) that are electrically connected to the controller. The electromagnetic proportional valve (900) is located in the bypass throttling oil passage (702) and is configured to adjust the flow cross section of the bypass throttling oil passage (702); The position sensor (801) and the speed sensor (802) are installed on the inner tube (200) or the outer tube (100) to collect the position information and motion speed information of the connecting rod (500) relative to the inner tube (200), respectively. The controller is used to determine whether the link (500) has entered the buffer working area based on the position information, and to determine whether the link (500) is in a compressed state moving toward the mechanical compression limit position based on the motion speed information; The controller is also used to generate a flow-limiting control signal in response to the linkage (500) entering the buffer working area, being in a compressed state and the motion speed information reaching a preset speed threshold, so as to reduce the opening of the electromagnetic proportional valve (900), reduce the flow rate of the oil flowing through the bypass throttling oil passage (702), and increase the flow rate of the oil flowing through the basic damping oil passage (701) to form a pre-limited hydraulic damping zone before the mechanical compression limit position.

2. The truck shock absorber according to claim 1, characterized in that: The buffer working area is determined based on the axial distance between the piston valve assembly (600) and the bottom valve assembly (700); The mechanical compression limit position is the position of the connecting rod (500) when the axial distance between the piston valve assembly (600) and the bottom valve assembly (700) reaches the preset minimum axial distance; The pre-limit hydraulic damping zone is located within the stroke range of the piston valve assembly (600) before it reaches the mechanical compression limit position.

3. The truck shock absorber according to claim 1, characterized in that: The bypass throttling oil circuit (702) includes an oil inlet (901), an adjustable valve chamber (903), and an oil outlet (902). The oil inlet (901) is connected to the working chamber (10); The oil outlet (902) is connected to the oil storage chamber (20); The adjustable valve chamber (903) is connected between the oil inlet (901) and the oil outlet (902); The electromagnetic proportional valve (900) is at least partially disposed within the adjustable valve chamber (903).

4. The truck shock absorber according to claim 1, characterized in that: The electromagnetic proportional valve (900) is a normally open electromagnetic proportional valve. The normally open electromagnetic proportional valve maintains its normally open position when it does not receive a current limiting control signal from the controller. The normally open position is the preset initial position.

5. A control method applied to a truck shock absorber according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Obtain the position information of the connecting rod (500) relative to the inner tube (200) collected by the position sensor (801), and the motion speed information of the connecting rod (500) relative to the inner tube (200) collected by the speed sensor (802); S2. Determine whether the link (500) has entered the buffer working area based on the position information; S3. In response to the link (500) entering the buffer working area, being in a compressed state moving toward the mechanical compression limit position and the motion speed information reaching the preset speed threshold, a flow limiting control signal is generated to reduce the opening of the electromagnetic proportional valve (900). S4. According to the flow limiting control signal, reduce the opening of the electromagnetic proportional valve (900) to reduce the flow rate of the oil flowing through the bypass throttling oil circuit (702) and increase the flow rate of the oil flowing through the basic damping oil circuit (701), forming a pre-limit hydraulic damping zone before the mechanical compression limit position. S2 includes the following sub-steps: S21. Determine the axial distance between the piston valve assembly (600) and the bottom valve assembly (700) based on the position information; S22. In response to the axial distance between the piston valve assembly (600) and the bottom valve assembly (700) being less than or equal to a preset buffer distance, determine that the connecting rod (500) enters the buffer working area; The mechanical compression limit position is the position of the connecting rod (500) when the axial distance between the piston valve assembly (600) and the bottom valve assembly (700) reaches the preset minimum axial distance, and the preset buffer distance is greater than the preset minimum axial distance. In S3, it is also determined whether the link (500) is in a compressed state moving toward the mechanical compression limit position based on the motion speed information; In response to the link (500) entering the buffer working area, being in a compressed state, and the motion speed information reaching the preset speed threshold, a flow limiting control signal is generated.

6. The control method for a truck shock absorber according to claim 5, characterized in that: In S3, a current limiting control signal is generated based on the opening degree control relationship; The opening control relationship includes a control function with the axial distance and movement speed information between the piston valve assembly (600) and the bottom valve assembly (700) as independent variables and the target opening of the electromagnetic proportional valve (900) as the dependent variable; The target opening degree is positively correlated with the axial distance between the piston valve assembly (600) and the bottom valve assembly (700), and negatively correlated with the motion speed information.

7. The control method for a truck shock absorber according to claim 5, characterized in that: In S3, a flow-limiting control signal is generated based on the axial distance between the piston valve assembly (600) and the bottom valve assembly (700); In response to the axial distance between the piston valve assembly (600) and the bottom valve assembly (700) being greater than a preset intermediate distance and less than or equal to a preset buffer distance, a flow limiting control signal characterizing the first small rate is generated; In response to the axial distance between the piston valve assembly (600) and the bottom valve assembly (700) being less than or equal to a preset intermediate distance, a flow-limiting control signal characterizing the second closing rate is generated, wherein the second closing rate is greater than the first closing rate. In S4, when the opening of the electromagnetic proportional valve (900) is reduced according to the current limiting control signal, the actual opening change rate of the electromagnetic proportional valve (900) is not greater than the preset maximum closing rate.

8. The control method for a truck shock absorber according to claim 5, characterized in that: Before S2, it also includes: Receive collision prediction signals sent by external vehicle systems; In response to a collision prediction signal indicating a risk of a compressive impact that could cause the link (500) to enter the buffer zone at a velocity greater than a preset impact velocity threshold, perform at least one of the following pre-adjustment operations: Increase the preset buffer distance; Lower the preset speed threshold.

9. The control method for a truck shock absorber according to claim 5, characterized in that: The electromagnetic proportional valve (900) in the truck shock absorber has a reset structure that resets to a preset initial opening degree after power failure or a default opening degree holding mechanism. The preset initial opening degree is the opening degree of the electromagnetic proportional valve (900) when no flow limiting control is performed. After S1 acquires the location and velocity information, it also includes: In response to the position sensor (801) or speed sensor (802) acquiring a signal that exceeds the preset effective signal range, is lost, or remains unchanged for a preset duration, the output of the control signal used to adjust the opening of the electromagnetic proportional valve (900) is stopped, so that the electromagnetic proportional valve (900) maintains the preset initial opening through the reset structure or the default opening holding mechanism.

10. The control method for a truck shock absorber according to claim 5, characterized in that: The preset initial opening is the opening of the electromagnetic proportional valve (900) when no flow limiting control is performed; Following S4, it also includes: In response to the linkage (500) exiting the buffer working area, or the motion speed information being lower than the preset recovery speed threshold, a recovery control signal is generated to increase the opening of the electromagnetic proportional valve (900); The electromagnetic proportional valve (900) is restored to the preset initial opening degree according to the recovery control signal; S22 includes: Use the preset buffer distance as the entry determination distance; In response to the axial distance between the piston valve assembly (600) and the bottom valve assembly (700) being less than or equal to the entry determination distance, it is determined that the connecting rod (500) has entered the buffer working area; In response to the axial distance between the piston valve assembly (600) and the bottom valve assembly (700) being greater than the exit determination distance, it is determined that the connecting rod (500) has exited the buffer working area and the exit determination distance is greater than the entry determination distance.

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