Electromagnetic seat suspension with parallel stiffness and control method

Abstract

The invention discloses a commercial vehicle electromagnetic seat suspension system with parallel rigidity and a control method of the commercial vehicle electromagnetic seat suspension system. The commercial vehicle electromagnetic seat suspension system comprises a seat suspension mechanical structure, an electromagnetic damper, an air spring and a resistance control system. The seat suspension mechanical structure mainly comprises a top plate, a mounting seat and a fork-shaped structure; the electromagnetic damper comprises a lifting lug, a push rod, a ball screw, a damper end cover, a direct current motor, a synchronous belt, a synchronous wheel and a clockwork spring; the lifting lug is connected with a seat suspension mechanical structure; the air spring is connected with the fork-shaped structure; the damping device has the beneficial effects that the problem that the damping of the seat suspension needs to be manually adjusted or cannot be adjusted is solved; the problem that an existing electromagnetic damper is too large in size and difficult to be directly installed on a seat suspension is solved. The problem that an existing seat suspension makes contact with the bottom or the top in the extreme vibration environment is solved.

Description

Technical Field

[0001] The present application belongs to the technical field of seat suspensions, and in particular relates to a seat suspension equipped with an electromagnetic damper and an air spring. Background Art

[0002] In recent years, improving the riding experience has received much attention. During driving, long-term exposure to low-frequency vibrations will affect the comfort and health of drivers and passengers. Therefore, improving seat suspension is the most direct way to improve driver comfort.

[0003] The seat suspension mainly uses a passive hydraulic damper, which is not controllable. The electromagnetic damper has good controllability and can adjust the damping according to different road conditions. However, the existing electromagnetic damper is large in size, and it is difficult to directly replace the passive damper without changing the mechanical structure of the seat suspension. In addition, under extreme working conditions, the seat suspension installed with an air spring will be subjected to vibration excitation higher than its own vibration reduction capacity. Due to the small stiffness of the air spring, the movement of the seat suspension is limited by its own structure to the limit, resulting in a "bottoming out or touching the top" phenomenon, which will cause harm to the human body. Therefore, in order to further explore the performance of the semi-active seat suspension, it is necessary to change the structure of the electromagnetic damper to adapt it to the size of the seat suspension, and to achieve more suitable damping adjustment according to different working conditions. The "bottoming out or touching the top" problem is solved by increasing the stiffness and damping force, and better seat suspension performance is obtained.

[0004] Patent content

[0005] In order to overcome the shortcomings of the prior art, the present invention provides an electromagnetic seat suspension system and control method. The patent solves the problem of seat suspension controllability by redesigning the structure and size of the electromagnetic damper, while making up for the defect that the electromagnetic damper is difficult to directly replace the passive damper, and effectively solves the "bottoming out or topping out" problem of the seat suspension.

[0006] To achieve the above purpose, the technical solution of this patent is:

[0007] An electromagnetic seat suspension system comprises: a seat suspension mechanical structure, an electromagnetic damper, and an air spring.

[0008] The seat suspension mechanical structure is mainly composed of a top plate and a mounting seat connected by a fork structure.

[0009] The electromagnetic damper is internally provided with a lifting lug, a push rod, a ball screw, a damper end cover, a DC motor, a synchronous belt, a synchronous wheel, a spiral spring, a guide sealing cover, and a sealing ring. The lifting lug and the end cover of the electromagnetic damper are respectively connected to the upper plate and the lower plate of the seat suspension mechanical structure.

[0010] The ball screw includes a double-row angular contact ball bearing, a screw, a screw nut, a locking nut and a guide slider. The tail of the screw is processed with a shaft shoulder and a thread. The locking nut is meshed with the threaded part of the ball screw. The locking nut and the shaft shoulder together realize the positioning of the double-row angular contact ball bearing. The tail of the screw is processed with a keyway. The synchronous wheel is connected to the ball screw through a set screw. The guide slider is connected to the screw nut through a set screw, and the head of the guide slider is meshed with the push rod through a thread.

[0011] The motor shaft of the brushless DC motor is processed with a keyway, and the synchronous wheel is connected to the DC motor via a set screw.

[0012] The end cover is provided with five positioning holes, and the bolts on the end cover are connected to the mounting seat through the positioning holes. A lifting ear is provided at the rear of the end cover, and the upper plate of the seat suspension is connected to the electromagnetic damper through the lifting ear.

[0013] The mounting seat is divided into an upper part and a lower part. The upper part of the mounting seat is processed with threads, and the lower part is processed with a motor shaft hole and a motor positioning hole. The DC motor is connected to the mounting seat by screws. Five threaded holes are processed on the mounting seat, and the end cover is connected to the mounting seat by bolts.

[0014] The shell head is processed with a sealing ring groove, and the sealing ring is installed in the sealing ring groove of the shell head. Both ends of the shell are processed with threads of different lengths. The guide sealing cover is processed with threads inside and meshes with the shell head threads. The upper end of the mounting seat is processed with threads, and the rear end of the shell is connected to the mounting seat through threaded engagement.

[0015] The synchronous wheels are connected by a synchronous belt, and the synchronous belt of corresponding circumference is customized by calculating the center distance of the synchronous wheels and the number of teeth of the synchronous wheels.

[0016] The spring is fixed to the end of the ball screw, and the other end of the spring is fixed to the end cover. The spring has its own stiffness change characteristic, in which the stiffness change is 0 within the deformation range A, and the stiffness increases significantly after the deformation exceeds A.

[0017] The ball screw converts the linear motion of the electromagnetic damper into rotational motion, and the ball screw is fixed together with the spring spring by bolts.

[0018] The ball screw nut can drive the screw to rotate, and finally drive the motor to rotate through the synchronous wheel and the synchronous belt to generate an induced electromotive force, which can generate an induced current in the circuit. This current can cause the motor to experience a torque that hinders the relative motion. This torque can be transmitted to both ends of the electromagnetic damper, i.e., the damping force, through the ball screw structure.

[0019] The magnitude of the induced current is proportional to the rotation speed of the motor. When the motor rotates at a low speed, the induced current generated inside the motor is small, and when the motor rotates at a high speed, the induced current generated inside the motor is large.

[0020] A control method for a composite electromagnetic vibration absorber comprises the following steps:

[0021] Step 1: When the electromagnetic damper is working, the angle and speed of the motor shaft rotation are identified by the encoder on the motor shaft, and the stiffness force provided by the spring is calculated according to the spring stiffness curve;

[0022] Step 2: After the seat suspension is excited by vibration, the sensor installed on the seat suspension inputs the displacement of the upper and lower plates of the seat suspension into the control algorithm, and the stiffness force of the air spring is calculated according to the seat suspension height;

[0023] Step 3: Calculate the force required for the seat to suppress vibration based on the control algorithm. The damping force generated by the motor is proportional to the equivalent current in the motor's internal coil, and the equivalent current is proportional to the motor speed and the resistance in the external circuit. When the signal collected by the sensor is input into the controller, the ideal damping force under the current working condition is calculated based on the control algorithm in combination with the stiffness force.

[0024] Step 4: The ideal resistance value is calculated based on the proportional relationship between the damping force and the resistance. The controller outputs a control signal to change the resistance value in the external circuit to achieve the vibration reduction effect of the seat suspension.

[0025] The beneficial effects of the present invention are as follows:

[0026] 1. The present invention uses a DC motor to output damping force, realizes step-by-step adjustment of damping by changing external resistance, and improves the controllability of damping of the seat suspension system.

[0027] 2. The present invention uses a synchronous belt and synchronous wheel transmission mechanism, and designs the ball screw and the DC motor into a foldable electromagnetic damper, which reduces the overall size and can directly replace the passive damper on the original seat suspension.

[0028] 3. The present invention uses a clockwork spring and an air spring as a parallel stiffness mechanism of the seat suspension, but the stiffness change response speed of the air spring is slow. When the stiffness force of the air spring is insufficient, the clockwork spring provides stiffness support, which prevents the seat suspension from "bottoming out or touching the top" without affecting the smoothness of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the accompanying drawings, in which:

[0030] Figure 1 This is a front view of the electromagnetic seat suspension;

[0031] Figure 2 It is a schematic diagram of the rear part of the electromagnetic seat suspension;

[0032] Figure 3 is a schematic diagram of an electromagnetic damper;

[0033] Figure 4 is a cross-sectional schematic diagram of an electromagnetic damper;

[0034] Figure 5 This is a schematic diagram of the installation of the clockwork spring;

[0035] Figure 6 Schematic diagram of the characteristic curve of the spring stiffness of the positive-spin mainspring;

[0036] Figure 7 Schematic diagram of the stiffness characteristic curve of the reverse-rotating mainspring;

[0037] Figure 8 It is a schematic diagram of the control method;

[0038] Fig. 9 It is a schematic diagram of the parallel stiffness electromagnetic seat suspension;

[0039] Legend: upper plate 1; lower plate 2; electromagnetic damper 3; fork structure 4; air spring 5; lifting ear 6; push rod 7; guide sealing cover 8; housing 9; mounting seat 10; end cover 11; DC motor 12; sealing ring 13; guide slider 14; screw nut 15; double-row angular contact ball bearing 16; locking nut 17; reverse-rotation spring 18; forward-rotation spring 19; synchronous belt 20; synchronous wheel 21; screw 22. Specific implementation plan

[0040] In order to make the technical solution of the present invention better understood by those skilled in the art or other fields, the specific implementation methods of the present invention are further described below.

[0041] See also Figure 1 and Figure 2 As shown, the present invention is installed in a car cab, and its technical solution includes an upper plate 1, a lower plate 2, an electromagnetic damper 3, a fork structure 4 and an air spring 5.

[0042] The air spring is installed on the fork-shaped structure 3, and the initial height of the seat is adjusted through the height adjustment valve, so as to bear the weight and maintain the seat height.

[0043] The electromagnetic damper includes 6 lifting ears, 7 push rods, 8 guide sealing covers, 9 housings, 10 mounting seats, 11 end covers, 12 DC motors, 13 sealing rings, 14 guide sliders, 15 lead screw nuts, 16 double-row angular contact ball bearings, 17 locking nuts, 18 reverse-rotation springs, 19 forward-rotation springs, 20 synchronous belts, 21 synchronous wheels and 22 lead screws.

[0044] like Figure 4 As shown, the ball screw includes a double-row angular contact ball bearing 16, a screw 22, a screw nut 15, a locking nut 17 and a guide slider 14. The tail of the screw 22 is processed with a shaft shoulder and a thread. The locking nut 17 is meshed with the threaded portion of the screw 22 and together with the shaft shoulder, realizes the positioning of the double-row angular contact ball bearing 16. The tail of the screw 22 is processed with a keyway, and the synchronous wheel 21 is connected to the screw 22 by a set screw. The guide slider 14 is connected to the screw nut 15 by a set screw, and the thread of the head of the guide slider 14 is connected to the push rod 7.

[0045] The motor shaft of the brushless DC motor 12 is processed with a keyway, and the synchronous wheel 21 is connected to the DC motor 12 via a set screw.

[0046] When relative motion occurs between the upper and lower plates, the lead screw nut 15 will move up and down to drive the lead screw 22 to rotate. At this time, the synchronous wheel 21 installed on the lead screw 22 will transmit the rotational motion to the synchronous wheel 21 of the DC motor through the synchronous belt 20. At this time, the rotor inside the DC motor 12 will generate a resistance torque due to the existence of the induced current.

[0047] like Figure 5 As shown, the ball screw converts the linear motion of the electromagnetic damper into rotational motion, the screw 22 is fixed together with the spring 18, the motor shaft of the DC motor 12 is fixed together with the positive spring 19, when the reverse spring 18 rotates counterclockwise, the "J"-shaped structure of the reverse spring 18 will be restricted by the end cover groove, and the reverse spring 18 will undergo elastic deformation as a whole to improve the stiffness. When the screw 22 rotates clockwise, the reverse spring 18 will Unrestricted by the groove on the end cover 11, the reverse-rotation spring 18 will be in an idling working mode; when the forward-rotation spring 19 installed on the DC motor 12 rotates clockwise, the "J"-shaped structure of the forward-rotation spring 19 will be restricted by the groove on the end cover, and the forward-rotation spring 19 as a whole will undergo elastic deformation to increase its stiffness. When the DC motor 12 rotates counterclockwise, the forward-rotation spring 19 will not be restricted by the groove on the end cover 11, and the forward-rotation spring 19 will be in an idling working mode.

[0048] like Figure 6 , Figure 7As shown, the stiffness changes of the reverse-rotating spring 18 and the forward-rotating spring 19 are related to the working condition of the electromagnetic damper 3. When the reverse-rotating spring 18 is in the idling working mode, the stiffness of the electromagnetic damper 3 itself is extremely small and can be ignored, and the overall stiffness of the seat suspension is determined by the air spring 5; when the reverse-rotating spring 18 is in the deformed working state, within a certain stroke range, the stiffness increase of the reverse-rotating spring 18 is extremely small, and has no effect on the operation of the electromagnetic damper 3. When the stroke exceeds point A, the stiffness of the reverse-rotating spring 18 increases sharply due to deformation, and the stiffness of the electromagnetic damper 3 increases.

[0049] like Figure 8 , Fig. 9 As shown, the present invention also provides a control method for a composite electromagnetic vibration absorber, comprising the following steps:

[0050] Step 1: When the electromagnetic damper is working, the angle and speed of the motor shaft rotation are identified by the encoder on the motor shaft, and the stiffness force provided by the spring is calculated according to the spring stiffness curve;

[0051] F1=k1*x

[0052] Among them, k1 is the stiffness of the spring, and x is the deformation of the spring.

[0053] Step 2, after the seat suspension is excited by vibration, the sensor installed on the seat suspension inputs the displacement of the upper plate and the lower plate of the seat suspension into the control algorithm, and the stiffness force of the air spring is calculated according to the height of the seat suspension;

[0054] F2=k2*h

[0055] Among them, k2 is the stiffness of the air spring under the current air pressure, and h is the deformation height of the air spring.

[0056] Step 3: Calculate the force required for the seat to suppress vibration according to the control algorithm. The damping force generated by the motor is proportional to the equivalent current in the coil inside the motor. The equivalent current is proportional to the motor speed and the resistance in the external circuit. When the signal collected by the sensor is input into the controller, the ideal damping force under the current working condition is calculated according to the control algorithm in combination with the stiffness force.

[0057] F e =F-F1-F2

[0058] T e =k i ·i

[0059] F e =-r g ·T e

[0060]

[0061]

[0062] Where F is the force required for the seat to suppress vibration, T e is the resistance torque of the motor, k i is the motor torque constant, i is the equivalent current of the motor internal coil, r g is the transmission ratio of the ball screw, F e is the output damping force, v is the linear motion speed at both ends of the electromagnetic damper, R is the resistance value in the external circuit, and r is the internal resistance of the motor;

[0063] Step 4, the ideal resistance value is calculated according to the proportional relationship between the damping force and the resistance, and the controller outputs a control signal to change the resistance value in the external circuit to achieve the vibration reduction effect of the seat suspension;

[0064]

[0065] Among them, R e is the ideal resistance value.

Claims

1. This patent discloses a parallel stiffness commercial vehicle electromagnetic seat suspension system and its control method, which is characterized by: Includes seats, seat suspension mechanical structure, electromagnetic dampers and air springs; 2. The electromagnetic damper according to claim 1, characterized in that: The two ends of the electromagnetic damper are connected to the top plate and the mounting seat. The seat suspension mechanical structure includes a top plate, a mounting seat and a fork structure; 3. The electromagnetic damper according to claim 1, characterized in that: The electromagnetic damper comprises a lifting lug, a push rod, a ball screw, an end cover, a DC motor, a synchronous belt, a synchronous wheel, a spring, a mounting seat, and a housing; 4. The ball screw according to claim 3, characterized in that: It includes a lead screw, a double-row angular contact ball bearing, a lead screw nut, a locking nut and a guide slider, wherein the lead screw is connected to the ball screw nut, the guide slider is connected to the ball screw nut, the push rod is connected to the guide slider, the double-row angular contact ball bearing is positioned by a shaft shoulder, and the locking nut is connected to the lead screw; 5. The clockwork spring according to claim 3, characterized in that: The spring is connected to the lead screw shaft and the motor shaft, and the "J"-shaped structure at the end of the spring is stuck in the end cover; 6. The clockwork spring according to claim 3, characterized in that: When the electromagnetic damper is working, only one of the spring on the screw shaft and the spring on the motor shaft is in working state, and the other is in idling state; 7. The electromagnetic damper according to claim 1, characterized in that: The ball screw converts the linear motion between the lifting lug and the end cover into the rotational motion of the synchronous wheel; 8. A control method for a parallel stiffness commercial vehicle electromagnetic seat suspension system, characterized in that: The following steps are involved: Step 1: When the electromagnetic damper is working, the angle and speed of the motor shaft rotation are identified by the encoder on the motor shaft, and the stiffness force provided by the spring is calculated according to the spring stiffness curve; Step 2: After the seat suspension is excited by vibration, the sensor installed on the seat suspension inputs the displacement of the upper and lower plates of the seat suspension into the control algorithm, and the stiffness force of the air spring is calculated according to the seat suspension height; Step 3: Calculate the force required for the seat to suppress vibration according to the control algorithm. The damping force generated by the motor is proportional to the equivalent current in the coil inside the motor. The equivalent current is proportional to the motor speed and the resistance in the external circuit. When the signal collected by the sensor is input into the controller, the ideal damping force under the current working condition is calculated according to the control algorithm in combination with the stiffness force. Step 4, calculate the ideal resistance value according to the proportional relationship between the damping force and the resistance, and the controller outputs a control signal to change the resistance value in the external circuit to achieve the vibration reduction effect of the seat suspension.

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