Method for calculating opening time of automobile glove box with damping

Abstract

The invention relates to the technical field of automobile part manufacturing and design, and particularly discloses an automobile damping glove box opening time calculation method which comprises the steps of automobile damping glove box structure determination, stress and motion analysis, kinetic equation derivation, differential equation numerical solution, four-order Runge-Kutta method solution, computer software solution and the like. The method is scientific and reasonable in step, the opening time of the automobile glove box with the damping function is finally and correctly obtained according to the actually determined structure of the automobile glove box with the damping function, important substantive reference value is achieved for designing buffering damping of a glove box damping device, designers can be helped to reasonably determine proper damping of the glove box damping device, and the design efficiency is improved. The situation that a designer repeatedly adjusts and debugs related components of the damping device, a large amount of time and energy are consumed, and the design work efficiency is seriously affected is avoided.

Description

Technical Field

[0001] This invention relates to the field of automotive parts manufacturing and design technology, and in particular to a method for calculating the opening time of a damped glove box in an automobile. Background Technology

[0002] Automotive glove boxes are often equipped with damping devices. The core function of these devices is to control the opening speed of the glove box, providing a smooth and stable operating experience. Traditional glove boxes rely on gravity to fall rapidly when opened. If fragile items such as water cups or glass bottles are placed inside, the vibration can easily cause damage. The damping device, through its internal structure, generates appropriate resistance to slow down the opening speed of the glove box lid, preventing items from tipping over or spilling due to sudden opening, and avoiding the impact noise caused by excessive force, thus reducing noise interference and making every operation more elegant and composed. However, the damping effect of this device is unsuitable if it is too strong or too weak, and this is directly reflected in the opening speed and time of the glove box. Some OEMs even use the opening time of the glove box as a measure of the damping effect. Designers often need to repeatedly adjust and debug the various components of the damping device to obtain the appropriate damping, which consumes a lot of time and energy and seriously affects design efficiency. Summary of the Invention

[0003] The purpose of this invention is to address the aforementioned technical problems by providing a method for calculating the opening time of a damped glove box in an automobile. The technical solution adopted by this invention is as follows:

[0004] A method for calculating the opening time of a damped glove box in an automobile, characterized by comprising the following steps:

[0005] Step 1: Determine the structure of the damped glove box in the car.

[0006] The damped glove box includes a glove box assembly, a cover, a spindle, and a damper. The cover has a limiting hook on its inner side, and the glove box assembly has a limiting post corresponding to the limiting hook of the cover. The limiting post is hinged to the glove box assembly via the spindle. The damper is fixed to the glove box assembly. When the cover is opened, the limiting hook is damped by the damper, which slows down the opening speed of the cover. When the limiting hook opens and contacts the limiting post of the glove box assembly, the cover is in its maximum open state.

[0007] Step 2: Force and Motion Analysis

[0008] 1. Force Analysis

[0009] Force analysis is performed based on the actual damped glove box mechanism in automobiles:

[0010] Point A is set as the origin, which is the center of the spindle, i.e., the origin A;

[0011] B is the damping point, which is the fixed installation and connection point between the damper and the glove box assembly.

[0012] C is the center of gravity, which is the position of the center of gravity of the entire box lid;

[0013] D is the pull point, which is the point where the pull rope on the damper is connected to one end of the limit hook on the box cover. That is, the part where the pull rope pulls the box cover is the pull point D.

[0014] The distance from the center of gravity of the box cover to the center of the spindle, and from its center of gravity C to the origin A, is the distance between the center of gravity, which is the box cover arm AC, with a length of L.

[0015] The point from which the pull rope pulls the box cover to the center of the spindle is the pull point D. The distance from the pull point D to the origin A is the radius of rotation of the pull rope, which is the pull rope arm AD, and the length is S.

[0016] The distance from the point where the pull rope pulls the box cover to the fixed connection point between the damper and the glove box assembly is the pull point D to the damping point B, which is the pull rope body BD.

[0017] 2. Introduce a rectangular coordinate system

[0018] Let A be the origin of the rectangular coordinate system, then:

[0019] θ: represents the angle between the box cover arm AC and the y-axis, which is the box cover arm rotation angle θ;

[0020] The angle between the rope arm AD and the y-axis is the rope arm rotation angle.

[0021] γ: represents the angle between the lid arm AC and the pull rope arm AD, i.e., the arm angle γ;

[0022] α: represents the angle between the rope arm (AD) and the rope body (BD), which is the rope angle α;

[0023] θ0: This represents the initial angle between the cover arm AC and the y-axis when the cover is closed. In this case, it is 20.1 degrees (the design range is generally 18-25 degrees).

[0024] θ1: This represents the angle between the cover arm AC and the y-axis when the cover is opened to its maximum angle, which is the maximum angle θ1. In this case, it is 70.1 degrees (the design range is generally 65-75 degrees).

[0025] 3. Drag the coordinates of point D

[0026] Let point A be the origin (0,0), and let the angle between the rope arm AD and the vertical y-axis be the angle of rotation of the rope arm. Since the rope arm AD = S, the coordinates of the pulling point D are (X...d ,Y d )for:

[0027]

[0028] 4. The real-time angle between the rope-pulling arm AD and the rope body BD, and its rope-pulling angle α.

[0029] The fixed coordinates of the damping point B are (X... b ,Y b ),vector vector

[0030] From the vector dot product, we can obtain: in:

[0031] Vector dot product:

[0032] Length of the module:

[0033] 5. Functional relationship between real-time pull rope angle α and box cover arm rotation angle θ

[0034] Based on the inner product, we can obtain the functional relationship between the rope angle α and the rope arm rotation angle φ.

[0035] Will Substituting into the previous equation, we get:

[0036]

[0037] The value of the arm angle γ is a known constant, which gives the functional relationship between the angle between the rope arm AD and the rope body BD (the rope angle α) and the angle between the box cover arm AC and the y-axis (the box cover arm rotation angle θ).

[0038] 6. Angular velocity ω

[0039] The angular velocity ω is the angular velocity of the rope arm AD rotating around its radius, and its magnitude is the first derivative of the box cover arm's rotation angle θ with respect to time. Counterclockwise is positive; during rigid rotation, the angular velocities of the box cover arm AC and the rope arm AD are the same.

[0040] 7. Linear velocity V d

[0041] The product of the angular velocity ω and the length S of the rope arm AD is the linear velocity V of the point D rotating about the origin A. d V d =ωS, because it rotates around the origin A, its direction is perpendicular to the rope arm AD;

[0042] 8. Pull-out speed V r

[0043] The pulling point D of the rope has a pulling speed V. r It is speed V d The component along the direction BD of the rope body, due to the velocity V d Perpendicular to the rope arm AD, the angle between the rope arm AD and the rope body BD is the rope angle α. Its component is: pull-out speed. That is, the linear velocity V of the drawn wire r =V d sinα=ωS sinα;

[0044] Step 3: Derivation of the dynamic equations

[0045] 1. Damping force F d

[0046] Damping force F d =kV r =kωS sinα, its direction is along the rope body BD and points to the damping point B, which prevents the damper rope from being pulled out;

[0047] Damping force F d With the damper cable pull-out speed V r Proportional, k is a proportionality coefficient. The proportionality coefficient k is obtained by fitting the damping characteristic curve and data of the damper tensile test through software.

[0048] 2. Damping torque M d

[0049] Damping force F d The lever arm about the origin A: the perpendicular distance from the origin A to the rope BD is

[0050] d = S sin(π-α) = S sinα.

[0051] Damping torque: M d =-F d d=-kωS 2 (sinα) 2 Damping torque M d Since it is opposite to the direction of rotation, it is a negative value;

[0052] 2. Gravitational torque M g

[0053] The gravitational torque M g =mgLsinθ, where: m is the mass of the glove box lid, g is the acceleration due to gravity, the distance from the center of gravity C of the lid to the origin A of the spindle (i.e., the length of the lid arm AC is L), and θ is the angle between the lid and the vertical y-axis (i.e., the rotation angle of the lid arm θ). The lid opens due to its gravity, and a gravitational torque M is formed by the distance between the center of gravity of the lid arm AC and the gravitational axis.g gravitational torque M g The torque is positive when rotating counterclockwise.

[0054] 3. Equations of rotation

[0055] (1) Obtain the moment of inertia J

[0056] The moment of inertia J is obtained through CATIA software. In the CATIA drawing page, according to the actual object of the damped glove box of this invention, a solid object graphic is drawn. Then, the moment of inertia measurement function is used to select the solid object graphic to be measured, select the mandrel as the rotation axis, and input the density of the selected solid object TPO material to obtain the moment of inertia, i.e., the moment of inertia J. At the same time, the center of gravity coordinates of the glove box lid can be obtained in the page for measuring the moment of inertia J.

[0057] (2) Generating the rotation equation

[0058] According to the laws of rigid body rotation: the moment of inertia J and angular acceleration The product equals the net external torque.

[0059] That is, the resultant external torque In the formula: J is the moment of inertia and angular acceleration. Let θ be the second derivative of the box cover arm rotation angle with respect to time, and ∑M be the resultant torque, which is the sum of the gravitational torque and the damping torque.

[0060] Then the resultant external torque That is

[0061] Step 4: Numerical Solution of Differential Equations

[0062] 1. Transform the system of equations

[0063] According to the laws of rigid body rotation: net external torque Let y1 = θ, As mentioned above, the rope angle α and the rope arm rotation angle Functional relationship in Then the resultant external torque in the dynamic equation It can be transformed into a system of first-order equations:

[0064]

[0065] Where α=α(y1) is from Substituting the geometric relationships into the calculation, the initial conditions are: when t = 0: y1(0) = θ0 (initial angle), y2(0) = 0 (default initial angular velocity is 0);

[0066] Step 5: Solve using the fourth-order Runge-Kutta method

[0067] Runge-Kutta method is a high-precision numerical method. This invention uses the most commonly used fourth-order Runge-Kutta method, which achieves high-precision discretization solution through multi-slope weighted averaging.

[0068] 1. Iterative calculation formula:

[0069] For a time step h, the state vector (one-dimensional array) is y = [y1, y2]. T Updated to:

[0070]

[0071] in In and These are the right-hand terms of the equations in the aforementioned system of first-order differential equations;

[0072] The calculation terminates when y1(t) ≥ θ1 (counterclockwise rotation, θ1 > θ0), outputting time t of θ1.

[0073] Step Six: Solve using computer software

[0074] This invention solves the problem using Python programming software. The source program is written in Python and its core contains 7 modules: Module 1 Physical parameter initialization input module, Module 2 Tension arm AD mechanical angle calculation module, Module 3 Dynamic equation solving module, Module 4 Runge-Kutta algorithm module, Module 5 Glove box lid rotation time solving module, Module 6 Calculation result motion plotting module, and Module 7 Motion animation creation module.

[0075] 1. Physical parameter initialization input module

[0076] The physical parameter initialization input module includes the option to manually input the following values:

[0077] The parameters include the moment of inertia J of the glove box lid, the mass m of the glove box lid, the length L of the lid arm AC, the length S of the rope arm AD, the damping coefficient of the rope 2, the arm angle γ, the coordinates of point B at the fixed connection between the damper and the glove box assembly STa, the initial angle θ0, and the target angle θ1. This module also calls the glove box lid rotation time calculation module (module 5), the motion plotting module for the calculation results (module 6), and the motion animation creation module (module 7). When calling module 5, the time array of the entire rotation process is returned, and the last element in the time array is extracted separately, which is the final opening time of the glove box lid.

[0078] 2. Cable-stayed arm AD mechanical angle calculation module

[0079] The AD mechanical angle calculation module for the rope-pulling arm includes the following:

[0080] Two functions are defined. The first function takes as input the angle θ between the lid arm AC and the y-axis, and the angle γ between the lid arm AC and the pull rope arm AD, and returns the angle γ between the pull rope arm AD and the y-axis. The second function takes the angle between the center of gravity arm AC and the y-axis (the rotation angle θ of the box cover arm), the angle between the box cover arm AC and the pull rope arm AD (the arm angle γ), the length S of the pull rope arm AD, and the coordinates of the damping point B at the fixed connection between the damper and the glove box assembly as inputs. It calculates the vector dot product and the modulus to obtain the cosine value of the pull rope angle α between the pull rope arm AD and the pull rope body BD. Finally, it returns the angle value of the pull rope angle α, which prepares for calling the module 3 dynamic equation solving module and the module 7 motion animation creation module.

[0081] 3. Dynamic Equation Solving Module

[0082] The dynamic equation solving module includes the following:

[0083] The module for calculating the mechanical angle of the rope arm AD is called to obtain the angle α. The dynamic equations are defined, transforming the second-order differential equations into a system of first-order differential equations. The parameter values ​​passed through the formal parameters include: the current time t, the state vector y containing angle and angular velocity parameters (i.e., the moment of inertia J of the glove box lid, the mass m of the glove box lid, the gravitational acceleration g, the distance from the center of gravity L of the glove box lid, the length S of the rope arm AD, the damping coefficient k of the damper, the arm angle γ, and the coordinates of the damping point B. The returned result is a one-dimensional array containing angular velocity and angular acceleration values, preparing for the call to the Runge-Kutta algorithm module in module 4.

[0084] 4. Runge-Kutta Algorithm Module

[0085] The Runge-Kutta algorithm module includes the following:

[0086] The dynamic equation solving module is invoked, and the solution is updated by sampling multiple slopes k1, k2, k3, and k4 at different locations using the Runge-Kutta algorithm, and then weighted and averaged. Geometrically, this is represented by approximating the curve using the "average direction of multiple local tangents". The parameters input are: the current time value t, the state vector value y containing angle and angular velocity parameters, i.e., the moment of inertia J of the glove box lid, the mass m of the glove box lid, the gravitational acceleration g, the length L of the lid arm AC, the length S of the rope arm AD, the damping coefficient k of the damper, the arm angle γ, and the coordinates of the damping point B, etc., and the time step value h. Finally, the parameters θ of the lid arm rotation and ω of the angular velocity are returned, which are prepared for subsequent calls in the glove box lid rotation time solving module in module 5.

[0087] 5. Module for calculating the rotation time of the glove box lid

[0088] The glove box lid rotation time calculation module includes the following:

[0089] The Runge-Kutta algorithm module (Module 4) is invoked to calculate the rotation time of the glove box lid and record the changes in angle and angular velocity over time. The following parameters are input: glove box lid moment of inertia J, glove box lid mass m, gravitational acceleration g, length L of lid arm AC, length S of rope arm AD, damping coefficient k of the damper, arm angle γ (the angle between lid arm AC and rope arm AD), coordinates of damping point B, and the initial angle θ0 between lid arm AC and the y-axis. The initial angle, i.e., the initial angle θ0, and the angle between the glove box cover arm AC and the y-axis when the glove box cover is opened to its maximum angle, i.e., the maximum angle θ1; the time step h value; and the maximum number of iterations. Returns: time result values, time array, angle array, and angular velocity array. The time, angle, and angular velocity returned in each iteration are stored in the corresponding history arrays, providing a basis for subsequent drawing of the "angle-time curve," "acceleration-time curve," and "animation of the glove box cover's motion."

[0090] 6. Motion plotting module for calculation results:

[0091] The motion plotting module for the calculation results includes the following:

[0092] The function calls the historical arrays of time, glove box lid opening angle, and glove box lid rotation angular velocity returned from the glove box lid rotation time solution module in module 5 to plot the "angle-time curve" and "acceleration-time curve". The main program will then call this function to plot the corresponding curves, showing the changes of the glove box lid's angles and angular velocities over time.

[0093] 7. Create a motion animation module:

[0094] The motion animation creation module includes the following:

[0095] The program calls the AD mechanical angle calculation module for the rope arm in module 2 and the time and angle history arrays in the glove box lid rotation time solution module in module 5. Based on the time values ​​in the time history array, the program determines the number of frames for animation playback to ensure that there are enough frames to display the animation. The main program will call this function to draw the animation of the entire process of the glove box lid opening.

[0096] The damper includes a housing, a pull rope, a compression spring, a perforation, a top cover, a shaft, and a rubber ring. The shaft is slidably mounted inside the hollow housing. The rubber ring is fixed to the shaft, and its outer edge slides against the inner wall of the housing. The top cover has a perforation and is fixed to the open end of the housing. The two ends of the compression spring abut against the shaft and the top cover, respectively. One end of the pull rope protrudes from the top cover into the hollow housing, passes through the compression spring, and is connected to the shaft. The other end is connected to one end of the limit hook of the cover. The damper generates buffer damping by the sliding of the shaft and the rubber ring and the elastic force of the compression spring.

[0097] This invention provides a method for calculating the opening time of a damped glove box in automobiles. The method is rigorous, scientific, and logically structured. Based on the actual determined structure of the damped glove box, it accurately calculates the opening time. This method provides significant reference value for designing the buffer damping of glove box damping devices. It helps designers rationally determine the appropriate damping for the glove box damping device, avoiding the need for designers to repeatedly adjust and debug the design of various components of the damping device, which consumes a lot of time and energy and seriously affects design efficiency. Attached Figure Description

[0098] The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this invention, are used to explain the invention in conjunction with illustrative embodiments and descriptions, and do not constitute an undue limitation of the invention.

[0099] Figure 1 A schematic diagram of a car's damped glove box and its closed position;

[0100] Figure 2 A schematic diagram of a car's damped glove box and its open position;

[0101] Figure 3 A schematic diagram showing the connection between the glove box lid and the damper;

[0102] Figure 4 This is a cross-sectional view of the damper structure;

[0103] Figure 5 for Figure 3 Force analysis diagram of the connection between the glove box lid and the damper;

[0104] Figure 6 This is a graph showing the damping characteristic of the damper.

[0105] Figure 7 The damping characteristic diagram of the damper;

[0106] Figure 8 A graph showing the relationship between the rotation angle of the glove box lid and time.

[0107] Figure 9A graph showing the relationship between the rotational angular velocity of the glove box lid and time.

[0108] Figure 10 Screenshot of the glove box lid rotating animation;

[0109] In the diagram: 1-Outer shell; 2-Pull cord; 3-Compression spring; 4-Perforation; 5-Top cover; 6-Shaft core; 7-Rubber ring; STa-Glove box assembly; STb-Box cover; STc-Limit hook; STd-Spindle. Detailed Implementation

[0110] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described below are only for explaining the invention. Keywords that need attention in these descriptions, including "pull rope" and "limiting hook," are merely customary names and used for ease of description and simplification; therefore, they should not be construed as limitations on the invention. In the following description, constants and variables that appear and are annotated for the first time in the text and its expressions are omitted for brevity when they appear again in the text and its expressions.

[0111] The present invention provides a method for calculating the opening time of a damped glove box in an automobile, comprising the following methods and steps:

[0112] Step 1: Determine the structure of the damped glove box in the car.

[0113] like Figures 1-3 The following describes a method for calculating the opening time of a damped glove box in an automobile. A typical damped glove box includes a glove box assembly STa, a cover STb, a spindle STd, and a damper. The cover STb has a limiting hook STc on its inner side, and the glove box assembly STa has a limiting post corresponding to the limiting hook STc on the cover STb, and is hinged to the glove box assembly STa via the spindle STd. The damper used in this embodiment is the damper disclosed in the utility model patent (authorization announcement number CN210164834U), such as... Figure 4As shown, the damper includes a housing 1, a pull rope 2, a compression spring 3, a perforation 4, a top cover 5, a shaft core 6, and a rubber ring 7. The shaft core 6 is slidably installed inside the hollow housing 1. The rubber ring 7 is fixed on the shaft core 6, and its outer edge slides against the inner wall of the housing 1. The top cover 5 has a perforation 4, which is fixed to the open end of the housing 1. The two ends of the compression spring 3 abut against the shaft core 6 and the top cover 5, respectively. One end of the pull rope 2 protrudes from the top cover 5 into the hollow housing 1, passes through the compression spring 3, and is connected to the shaft core 6. The other end is connected to one end of the limiting hook STc of the cover STb. The damper generates buffer damping by the sliding of the shaft core 6 and the rubber ring 7 and the elastic force of the elastic spring 3. The damper is fixed on the glove box assembly STa. When the glove box cover STb is opened, its limiting hook STc is damped by the damper to slow down the opening speed of the glove box cover STb. When the limiting hook STc opens and contacts the limiting post of the glove box assembly STa, the glove box cover STb is in its maximum open state.

[0114] Step 2: Force and Motion Analysis

[0115] 1. Force Analysis Diagram

[0116] Based on the actual damped glove box mechanism in automobiles, abstractly as follows: Figure 5 Force analysis diagram shown:

[0117] A is set as the origin, which is the center of the spindle STd (the hinge center between the glove box assembly STa and the cover STb).

[0118] B is the damping point, which is the fixed installation and connection point between the damper and the glove box assembly STa, i.e., the damper B;

[0119] C is the center of gravity, which is the position of the center of gravity of the entire box cover STb, i.e., the center of gravity C;

[0120] D is the pull point, which is the point where the pull rope 2 on the damper is connected to one end of the limit hook STc of the cover STb. That is, the part where the pull rope 2 pulls the cover STb, which is the pull point D.

[0121] The distance from the center of gravity of the cover STb to the center of the spindle STd, and from its center of gravity C to the origin A, is the distance between the center of gravity, which is the cover arm AC, with a length of L.

[0122] The pull rope 2 pulls the box cover STb to the center of the spindle STd. The distance from the pull point D to the origin A is the rotation radius of the pull rope 2, which is the pull rope arm AD, and the length is S.

[0123] The pull rope 2 extends from the point where it pulls the box cover STb to the point where the damper and glove box assembly STa are fixedly connected. This is the pull point D to the damping point B, which is the pull rope body BD.

[0124] 2. Introduce a rectangular coordinate system

[0125] Let A be the origin of the center of the mandrel STd, and then:

[0126] θ: Represents the angle between the box cover arm AC and the y-axis, which is the box cover arm rotation angle θ;

[0127] The angle between the rope arm AD and the y-axis is the rope arm rotation angle.

[0128] γ: Represents the angle between the lid arm AC and the pull rope arm AD (i.e., the constant value of ∠CAD, which is directly measured from the geometric data), which is the arm angle γ;

[0129] α: represents the angle between the rope arm AD and the rope body BD, which is the rope angle α;

[0130] θ0: This represents the initial angle between the cover arm AC and the y-axis when the cover STb is closed; in this embodiment, it is 20.1 degrees (the design range is generally 18-25 degrees).

[0131] θ1: Represents the angle between the cover arm AC and the y-axis when the cover STb is opened to the maximum angle, which is the maximum angle θ1; in this embodiment, it is 70.1 degrees (the design range is generally 65-75 degrees);

[0132] 3. Drag the coordinates of point D

[0133] Let point A be the origin (0,0), and let the angle between the rope arm AD and the vertical y-axis be the rope arm rotation angle. )for Since the rope arm AD = S, the coordinates of the pulling point D are (X... d ,Y d )for:

[0134]

[0135] 4. The real-time angle α between the rope arm AD and the rope body BD

[0136] The fixed coordinates of the damping point B are (X... b ,Y b ),vector vector

[0137] From the vector dot product, we can obtain: in:

[0138] Vector dot product:

[0139] Length of the module:

[0140] 5. Functional relationship between real-time pull rope angle α and box cover arm rotation angle θ:

[0141] According to the inner product, we can obtain the relationship between the rope angle α and the rope arm rotation angle. Functional relationship

[0142]

[0143] Will Substituting into the previous equation, we get:

[0144]

[0145] The value of the arm angle γ is a known constant, which gives the functional relationship between the angle between the rope arm AD and the rope body BD (the rope angle α) and the angle between the box cover arm AC and the y-axis (the box cover arm rotation angle θ).

[0146] 6. Angular velocity ω

[0147] The angular velocity ω is the angular velocity of the rope arm AD rotating around its radius, and its magnitude is the first derivative of the box cover arm's rotation angle θ with respect to time. Counterclockwise is positive; during rigid rotation, the angular velocities of the box cover arm AC and the rope arm AD are the same.

[0148] 7. Linear velocity V d

[0149] The product of the angular velocity ω and the length S of the rope arm AD is the linear velocity V of the point D rotating about the origin A. d V d =ωS, because it rotates around the origin A, its direction is perpendicular to the rope arm AD;

[0150] 8. Pull-out speed V r

[0151] The pulling point D of the rope has a pulling speed V. r It is speed V d The component along the direction BD of the rope body, due to the velocity V d Perpendicular to the rope arm AD, the angle between the rope arm AD and the rope body BD is the rope angle α. Its component is: pull-out speed. That is, the linear velocity V of the drawn wire r =V d sinα=ωS sinα;

[0152] Step 3: Derivation of the dynamic equations

[0153] 1. Damping force F d

[0154] Damping force F d =kV r=kωS sinα, its direction is along the rope body BD and points to the damping point B, which prevents the damper rope 2 from being pulled out;

[0155] Damping force F d With the damper pull rope 2 pulled out at speed V r The values ​​are directly proportional, where k is the proportionality coefficient. This proportionality coefficient k is obtained by fitting the test data (as shown in the table below) obtained from the damper tensile test using software. Figure 7 The diagram shows the fitting process of the damper proportional coefficient. In this embodiment, the proportional coefficient of the damper is k = 150.5.

[0156]

[0157] 2. Damping torque M d

[0158] Damping force F d The lever arm about the origin A is: the perpendicular distance d from the origin A to the rope BD is d = S sin(π-α) = Ssinα.

[0159] Damping torque: M d =-F d d=-kωS 2 (sinα) 2 Damping torque M d Since it is opposite to the direction of rotation, it is a negative value;

[0160] 3. Gravitational torque M g

[0161] The gravitational torque M g =mgLsinθ, where: m is the mass of the glove box lid, g is the acceleration due to gravity, the distance from the center of gravity C of the lid STb to the origin A of the spindle STd (i.e., the length of the lid arm AC is L), and θ is the angle between the lid and the vertical y-axis (the rotation angle of the lid arm θ). The lid STb opens due to its gravity, and the distance between the center of gravity of the lid arm AC forms a gravitational torque M. g Then the gravitational torque M g For driving torque (positive when rotating counterclockwise):

[0162] 4. Equations of rotation

[0163] (1) Obtain the moment of inertia J

[0164] In this embodiment, the moment of inertia J is obtained using CATIA software. CATIA software is a next-generation software solution product launched by Dassault Systèmes, France, and belongs to the category of three-dimensional computer-aided design / manufacturing application software systems. In this embodiment, firstly, in the CATIA drawing page, a solid object graphic is created based on the actual damped glove box of this invention. Then, using the moment of inertia measurement function (clicking the moment of inertia measurement button), the solid object graphic to be measured is selected, and the mandrel STd is selected as the rotation axis (corresponding to...). Figure 5 As shown at origin A), input the density of the selected entity object's TPO material as 1060 kg / m³. 3 The moment of inertia, J, can be obtained as 0.004 kg·m. 2 Meanwhile, the coordinates of the center of gravity of the glove box lid STb can be obtained from the page where the moment of inertia J is measured (corresponding to...). Figure 5 The center of gravity is shown as C);

[0165] (2) Generating the rotation equation

[0166] According to the laws of rigid body rotation: the moment of inertia J and angular acceleration The product equals the net external torque.

[0167] That is, the resultant external torque (In the formula: J is the moment of inertia and angular acceleration) Let θ be the second derivative of the box cover arm rotation angle with respect to time, and ∑M be the resultant torque (i.e., the sum of the gravitational torque and the damping torque).

[0168] Then the resultant external torque That is

[0169] Step 4: Numerical Solution of Differential Equations

[0170] 1. Transform the system of equations

[0171] According to the laws of rigid body rotation: net external torque Let y1 = θ, As mentioned above, the rope angle α and the rope arm rotation angle Functional relationship in Then the resultant external torque in the dynamic equation It can be transformed into a system of first-order equations:

[0172]

[0173] Where α=α(y1) is from Substituting the geometric relationships into the calculation, the initial conditions are: when t = 0: y1(0) = θ0 (initial angle), y2(0) = 0 (default initial angular velocity is 0).

[0174] Step 5: Solve using the fourth-order Runge-Kutta method

[0175] Runge-Kutta methods are high-precision numerical methods proposed by mathematicians Karl Runge and Martin Wilhelm Kutta in 1900. They are single-step iterative algorithms that approximate the solution to a differential equation by constructing a slope-weighted average of multiple intermediate points. Their core advantage lies in achieving high accuracy for solving ordinary differential equations (systems) without calculating higher-order derivatives. This invention employs the most commonly used fourth-order Runge-Kutta method (RK4), which achieves high-precision discretization through multi-slope weighted averaging.

[0176] 1. Iterative calculation formula:

[0177] For a time step h, the state vector (one-dimensional array) y = [y1, u2] T Updated to:

[0178]

[0179] in In and is the right-hand side term of the aforementioned first-order differential equation system.

[0180] The calculation terminates when y1(t) ≥ θ1 (counterclockwise rotation, θ1 > θ0), outputting time t of θ1.

[0181] Step Six: Solve using computer software

[0182] This invention uses Python programming to solve the problem. The source code includes defining and calculating the rotation angle of the rope arm. The module includes modules for defining the rope angle α, defining the dynamic equations (a system of first-order differential equations), defining the Runge-Kutta algorithm, solving for the rotation time, and solving for the rotation time.

[0183] The source code of this invention is written in Python, and its core contains 7 modules: Module 1 (physical parameter initialization input and glove box lid opening time calculation module), Module 2 (pull arm AD mechanical angle calculation module), Module 3 (dynamic equation solving module), Module 4 (Runge-Kutta algorithm module), Module 5 (glove box lid rotation time solving module), Module 6 (calculation result motion plotting module), and Module 7 (motion animation creation module).

[0184] Module 1: Physical parameter initialization input and glove box lid opening time calculation module

[0185] The physical parameter initialization input module includes the following manually input values:

[0186] The module includes the moment of inertia J of the glove box lid, the mass m of the glove box lid, the length L of the lid arm AC, the length S of the rope arm AD, the damping coefficient of the rope 2, the arm angle γ (the angle between the lid arm AC and the rope arm AD), the coordinates of point B at the fixed connection between the damper and the glove box assembly STa, the initial angle θ0, and the target angle θ1. This module also calls modules 5 (glove box lid rotation time calculation module), 6 (calculation result motion plotting module), and 7 (motion animation creation module). When module 5 is called, it returns the time array for the entire rotation process. The last element of the time array is extracted separately, which is the final opening time of the glove box lid, and the result is 1.275 seconds.

[0187] The physical parameter initialization input module includes the following source code and comments:

[0188]

[0189]

[0190] Module 2, Cable-stayed Arm AD Mechanical Angle Calculation Module

[0191] The AD mechanical angle calculation module for the rope-pulling arm includes the following:

[0192] Two functions are defined. The first function takes the angle between the lid arm AC and the y-axis (lid arm rotation angle θ) and the angle between the lid arm AC and the pull rope arm AD (arm angle γ) as input parameters, and returns the angle between the pull rope arm AD and the y-axis (pull rope arm rotation angle). The first function takes the angle between the center of gravity arm AC and the y-axis (box cover arm rotation angle θ), the angle between the box cover arm AC and the pull rope arm AD (arm angle γ), the length S of the pull rope arm AD, and the coordinates of the damping point B at the fixed connection between the damper and the glove box assembly STa as input. It calculates the vector dot product and the modulus to obtain the cosine value of the angle between the pull rope arm AD and the pull rope body BD (pull rope angle α). Finally, it returns the angle value of the pull rope angle α, which is used to prepare for the calls of module 3 (dynamic equation solving module) and module 7 (creating motion animation module).

[0193] Module 3, Solving the Dynamic Equations

[0194] The dynamic equation solving module includes the following:

[0195] Call module 2 (the rope arm AD mechanical angle calculation module) to obtain angle α; define the dynamic equation, transforming the second-order differential equation into a system of first-order differential equations, where the parameter values ​​passed through formal parameters include: t (current time value), y (state vector containing angle and angular velocity parameters), moment of inertia J of the glove box lid, mass m of the glove box lid, gravitational acceleration g, distance L of the center of gravity of the glove box lid, length S of the rope arm AD, damping coefficient k of the damper, arm angle γ, and coordinates of damping point B, etc.; return the result as a one-dimensional array containing angular velocity and angular acceleration values, in preparation for calling module 4 (Runge-Kutta algorithm module).

[0196] Module 4, Runge-Kutta Algorithm Module

[0197] The Runge-Kutta algorithm module includes the following:

[0198] Module 3 (the module for solving the dynamic equations) is called. The solution is updated by sampling multiple slopes k1, k2, k3, and k4 at different locations using the Runge-Kutta algorithm, weighted, and averaged. Geometrically, this approximates the curve using the "average direction of multiple local tangents." The parameters input are: t (current time value), y (state vector value including angle and angular velocity parameters), h (time step value), the glove box lid's moment of inertia J, the glove box lid's mass m, gravitational acceleration g, the length L of the lid arm AC, the length S of the rope arm AD, the damping coefficient k of the damper, the arm angle γ (the angle between the lid arm AC and the rope arm AD), and the coordinates of the damping point B. Finally, the parameters θ (lid arm rotation angle) and ω (angular velocity) are returned, preparing for subsequent calls in Module 5 (the module for solving the rotation time of the glove box lid).

[0199] Module 5, Glove Box Lid Rotation Time Calculation Module

[0200] The glove box lid rotation time calculation module includes the following:

[0201] Module 4 (Runge-Kutta Algorithm Module) is called to calculate the rotation time of the glove box lid and record the changes in angle and angular velocity over time. The following parameters are passed in: glove box lid moment of inertia J, glove box lid mass m, gravitational acceleration g, length of lid arm AC L, length of rope arm AD S, damping coefficient k, arm angle γ (the angle between lid arm AC and rope arm AD), coordinates of damping point B, angle θ0 (the initial angle between lid arm AC and the y-axis, i.e., initial angle θ0) and angle θ1 (the angle between lid arm AC and the y-axis when the glove box lid is opened to its maximum angle, i.e., maximum angle), time step h, and maximum number of iterations. The algorithm returns: time result values, time array, angle array, and angular velocity array. The time, angle, and angular velocity returned in each iteration are stored in the corresponding history array, providing a basis for subsequent plotting of the "angle-time curve," "acceleration-time curve," and "animation of glove box lid motion."

[0202] θ0: represents the initial angle between the cover arm AC and the y-axis when the cover (STb) is closed, which is the initial angle θ0;

[0203] θ1: This represents the angle between the cover arm AC and the y-axis when the cover (STb) is opened to its maximum angle, which is the maximum angle θ1.

[0204] Module 6, Motion Plotting of Calculation Results:

[0205] The motion plotting module for the calculation results includes the following:

[0206] The function calls the historical arrays of time, glove box lid opening angle, and glove box lid rotation angular velocity returned from module 5 (glove box lid rotation time calculation module) to plot the "angle-time curve" and "acceleration-time curve." The main program will subsequently call this function to plot the corresponding curves. See also... Figures 8-9 As shown, plot the curves of the glove box lid's motion and the changes of its angles and angular velocities over time.

[0207] Module 7, Creating Motion Animation Module:

[0208] The motion animation creation module includes the following:

[0209] The program calls module 2 (AD mechanical angle calculation module for rope arm) and module 5 (glove box lid rotation time solution module) to access the historical arrays of time and angle. It determines the number of frames for animation playback based on the time values ​​in the historical time array to ensure that there are enough frames to display the animation. The main program will call this function to draw the animation of the entire process of the glove box lid opening.

[0210] Animation of the movement of the glove box lid is generated, and the animation screenshots are as follows. Figure 10As shown.

[0211] The above description is merely a general embodiment of the present invention. For those skilled in the art, the present invention can have various modifications and variations, which will not be elaborated upon here. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention are included within the scope of protection claimed by the present invention.

Claims

1. A method for calculating the opening time of a damped glove box in an automobile, characterized in that, The following steps are included: Step 1: Determine the structure of the damped glove box in the car. The damped glove box includes a glove box assembly (STa), a cover (STb), a spindle (STd), and a damper. The cover (STb) has a limiting hook (STc) on its inner side. The glove box assembly (STa) has a limiting post corresponding to the limiting hook (STc) of the cover (STb) and is hinged to the glove box assembly (STa) through the spindle (STd). The damper is fixed on the glove box assembly (STa). When the cover (STb) is opened, the limiting hook (STc) is damped by the damper, which slows down the opening speed of the cover (STb). When the limiting hook (STc) opens and contacts the limiting post of the glove box assembly (STa) for a limit stop, the cover (STb) is in its maximum open state. Step 2: Force and Motion Analysis 1. Force Analysis Force analysis is performed based on the actual damped glove box mechanism in automobiles: A is set as the origin, which is the center of the spindle (STd), i.e., the origin A; B is the damping point, which is the fixed installation and connection point between the damper and the glove box assembly (STa). C is the center of gravity, which is the position of the center of gravity of the entire box cover (STb). D is the pull point, which is the point where the pull rope (2) on the damper is connected to one end of the limit hook (STc) of the box cover (STb). That is, the part where the pull rope (2) pulls the box cover (STb) is the pull point D. The distance from the center of gravity of the box cover (STb) to the center of the spindle (STd), and from its center of gravity C to the origin A, is the distance between the center of gravity, which is the box cover arm AC, with a length of L; The pull rope (2) pulls the box cover (STb) to the center of the spindle (STd), which is the pull point (D) to the origin (A), which is the rotation radius of the pull rope (2), also known as the pull rope arm AD, with a length of S; The pull rope (2) pulls the box cover (STb) from the point where the damper and glove box assembly (STa) are fixedly connected. The distance from the pull point D to the damping point B is the pull rope body BD.

2. Introduce a rectangular coordinate system Let A be the origin of the rectangular coordinate system, which is the center point of the mandrel (STd). Then: θ: represents the angle between the box cover arm AC and the y-axis, which is the box cover arm rotation angle θ; The angle between the rope arm AD and the y-axis is the rope arm rotation angle. γ: represents the angle between the lid arm AC and the pull rope arm AD, i.e., the arm angle γ; α: represents the angle between the rope arm AD and the rope body BD, which is the rope angle α; θ0: represents the initial angle between the cover arm AC and the y-axis when the cover (STb) is closed, which is the initial angle θ0; θ1: This represents the angle between the cover arm AC and the y-axis when the cover (STb) is opened to its maximum angle, which is the maximum angle θ1.

3. Drag the coordinates of point D Let point A be the origin (0,0), and let the angle between the rope arm AD and the vertical y-axis be the angle of rotation of the rope arm. Since the rope arm AD = S, the coordinates of the pulling point D are (X... d ,Y d )for:

4. The real-time angle between the rope-pulling arm AD and the rope body BD, and its rope-pulling angle α. The fixed coordinates of the damping point B are (X... b ,Y b ),vector vector From the vector dot product, we can obtain: in: Vector dot product: Length of the module:

5. Functional relationship between real-time pull rope angle α and box cover arm rotation angle θ: According to the inner product, we can obtain the relationship between the rope angle α and the rope arm rotation angle. Functional relationship Will Substituting into the previous equation, we get: The value of the arm angle γ is a known constant, which gives the functional relationship between the angle between the rope arm AD and the rope body BD (the rope angle α) and the angle between the box cover arm AC and the y-axis (the box cover arm rotation angle θ).

6. Angular velocity ω The angular velocity ω is the angular velocity of the rope arm AD rotating around its radius, and its magnitude is the first derivative of the box cover arm's rotation angle θ with respect to time. Counterclockwise is positive; during rigid rotation, the angular velocities of the box cover arm AC and the rope arm AD are the same.

7. Linear velocity V d The product of the angular velocity ω and the length S of the rope arm AD is the linear velocity V of the point D rotating about the origin A. d V d =ωS, because it rotates around the origin A, its direction is perpendicular to the rope arm AD; 8. Pull-out speed V r The pulling point D of the pull rope (2) has a pulling speed V. r It is speed V d The component along the direction BD of the rope body, due to the velocity V d Perpendicular to the rope arm AD, the angle between the rope arm AD and the rope body BD is the rope angle α. Its component is: pull-out speed. That is, the linear velocity V of the drawn wire r =V d sinα=ωS sinα; Step 3: Derivation of the dynamic equations 1. Damping force F d Damping force F d =kV r =kωS sinα, its direction is along the rope body BD and points to the damping point B, which prevents the damper rope 2 from being pulled out; Damping force F d With the damper pull rope (2) pulled out at a speed V r Proportional, k is a proportionality coefficient. The proportionality coefficient k is obtained by fitting the damping characteristic curve and data of the damper tensile test through software.

2. Damping torque M d Damping force F d The lever arm about the origin A: The perpendicular distance d from the origin A to the rope BD is d = Ssin(π-α) = Ssinα Damping torque: M d =-F d d=-kωS 2 (sinα) 2 Damping torque M d Since it is opposite to the direction of rotation, it is a negative value; 3. Gravitational torque M g The gravitational torque M g =mgLsinθ, where: m is the mass of the glove box lid, g is the acceleration due to gravity, the distance from the center of gravity C of the lid (STb) to the origin A of the spindle (STd), i.e., the length of the lid arm AC is L, and θ is the angle between the lid and the vertical y-axis, i.e., the rotation angle of the lid arm θ. The lid (STb) opens by its gravity, and the distance from the center of gravity of the lid arm AC forms a gravitational torque M. g gravitational torque M g The torque is positive when rotating counterclockwise.

4. Equations of rotation (1) Obtain the moment of inertia J The moment of inertia J is obtained through software. In the software drawing page, a solid object graphic is drawn according to the actual damping glove box. Then, the moment of inertia measurement function is used to select the solid object graphic to be measured, select the mandrel (STd) as the rotation axis, and input the density of the selected solid object TPO material to obtain the moment of inertia, i.e., the moment of inertia J. At the same time, the center of gravity coordinates of the glove box lid (STb) can be obtained in the page for measuring the moment of inertia J. (2) Generating the rotation equations According to the laws of rigid body rotation: the moment of inertia J and angular acceleration The product equals the net external torque. That is, the resultant external torque In the formula: J is the moment of inertia and angular acceleration. Let θ be the second derivative of the box cover arm rotation angle with respect to time, and ∑M be the resultant torque, which is the sum of the gravitational torque and the damping torque. Then the resultant external torque That is Step 4: Numerical Solution of Differential Equations 1. Transform the system of equations According to the laws of rigid body rotation: net external torque Let y1 = θ, As mentioned above, the rope angle α and the rope arm rotation angle Functional relationship in γ-θ, then the resultant external torque in the dynamic equation It can be transformed into a system of first-order equations: Where α=α(y1) is from Substituting the geometric relationships into the calculation, the initial conditions are: when t = 0: y1(0) = θ0 (initial angle), y2(0) = 0 (default initial angular velocity is 0); Step 5: Solve using the fourth-order Runge-Kutta method A fourth-order Runge-Kutta method is adopted, and high-precision discretization is achieved through multi-slope weighted averaging.

1. Iterative calculation formula: For a time step h, the state vector (one-dimensional array) is y = [y1, y2]. T Updated to: in In and These are the right-hand terms of the equations in the aforementioned system of first-order differential equations; The calculation terminates when y1(t) ≥ θ1 (counterclockwise rotation, θ1 > θ0), outputting time t of θ1.

2. The method for calculating the opening time of a damped glove box in an automobile according to claim 1, characterized in that, It also includes step six, solving with computer software. The source code contains 7 modules: Module 1, which is the physical parameter initialization input and glove box lid opening time calculation module; Module 2, which is the pull arm AD mechanical angle calculation module; Module 3, which is the dynamic equation solving module; Module 4, which is the Runge-Kutta algorithm module; Module 5, which is the glove box lid rotation time solving module; Module 6, which is the calculation result motion plotting module; Module 7, which is the motion animation creation module.

1. Physical parameter initialization input module The physical parameter initialization input module includes the option to manually input the following values: The moment of inertia J of the glove box cover, the mass m of the glove box cover, the length L of the cover arm AC, the length S of the rope arm AD, the damping coefficient of the rope (2), the arm angle γ, the coordinates of point B at the fixed connection between the damper and the glove box assembly STa, the initial angle θ0 and the target angle θ1 are all specified. At the same time, this module calls the glove box cover rotation time solution module 5, the motion drawing module for the calculation results module 6 and the motion animation creation module 7. When calling module 5, the time array of the entire rotation process is returned, and the last element in the time array is taken out separately, which is the final opening time of the glove box cover.

2. Cable-stayed arm AD mechanical angle calculation module The AD mechanical angle calculation module for the rope-pulling arm includes the following: Two functions are defined. The first function takes as input the angle θ between the lid arm AC and the y-axis, and the angle γ between the lid arm AC and the pull rope arm AD, and returns the angle γ between the pull rope arm AD and the y-axis. The second function takes the angle between the center of gravity arm AC and the y-axis (the rotation angle θ of the box cover arm), the angle between the box cover arm AC and the rope arm AD (the arm angle γ), the length S of the rope arm AD, and the coordinates of the damping point B at the fixed connection between the damper and the glove box assembly (STa) as input, calculates the vector dot product and the modulus, obtains the cosine value of the rope angle α between the rope arm AD and the rope body BD, and finally returns the angle value of the rope angle α, which prepares for calling the module 3 dynamic equation solving module and the module 7 motion animation creation module; 3. Dynamic Equation Solving Module The dynamic equation solving module includes the following: The module for calculating the mechanical angle of the rope arm AD is called to obtain the angle α. The dynamic equations are defined, transforming the second-order differential equations into a system of first-order differential equations. The parameter values ​​passed through the formal parameters include: the current time t, the state vector y containing angle and angular velocity parameters (i.e., the moment of inertia J of the glove box lid, the mass m of the glove box lid, the gravitational acceleration g, the distance from the center of gravity L of the glove box lid, the length S of the rope arm AD, the damping coefficient k of the damper, the arm angle γ, and the coordinates of the damping point B. The returned result is a one-dimensional array containing angular velocity and angular acceleration values, preparing for the call to the Runge-Kutta algorithm module in module 4.

4. Runge-Kutta Algorithm Module The Runge-Kutta algorithm module includes the following: The dynamic equation solving module is invoked, and the solution is updated by sampling multiple slopes k1, k2, k3, and k4 at different locations using the Runge-Kutta algorithm, weighted averaged, and then used. Geometrically, this is represented by approximating the curve using the "average direction of multiple local tangents". The parameters input are: the current time value t, the state vector value y containing angle and angular velocity parameters, i.e., the moment of inertia J of the glove box lid, the mass m of the glove box lid, the gravitational acceleration g, the length L of the lid arm AC, the length S of the rope arm AD, the damping coefficient k of the damper, the arm angle γ, and the coordinates of the damping point B, etc., and the time step value h. Finally, the parameters θ of the lid arm rotation and ω of the angular velocity are returned, which are prepared for subsequent calls in the glove box lid rotation time solving module in module 5.

5. Module for calculating the rotation time of the glove box lid The glove box lid rotation time calculation module includes the following: The Runge-Kutta algorithm module (Module 4) is invoked to calculate the rotation time of the glove box lid and record the changes in angle and angular velocity over time. The following parameters are input: glove box lid moment of inertia J, glove box lid mass m, gravitational acceleration g, length L of lid arm AC, length S of rope arm AD, damping coefficient k of the damper, arm angle γ (the angle between lid arm AC and rope arm AD), coordinates of damping point B, and the initial angle θ0 between lid arm AC and the y-axis. The initial angle, i.e., the initial angle θ0, and the angle between the glove box cover arm AC and the y-axis when the glove box cover is opened to its maximum angle, i.e., the maximum angle θ1; the time step h value; and the maximum number of iterations. Returns: time result values, time array, angle array, and angular velocity array. The time, angle, and angular velocity returned in each iteration are stored in the corresponding history arrays, providing a basis for subsequent drawing of the "angle-time curve," "acceleration-time curve," and "animation of the glove box cover's motion." 6. Motion plotting module for calculation results: The motion plotting module for the calculation results includes the following: The function calls the historical arrays of time, glove box lid opening angle, and glove box lid rotation angular velocity returned from the glove box lid rotation time solution module in module 5 to draw the "angle-time curve" and "acceleration-time curve". The main program will then call this function to draw the corresponding curves, showing the curves of how the glove box lid moves at each angle and angular velocity over time.

7. Create a motion animation module: The motion animation creation module includes the following: The program calls the AD mechanical angle calculation module for the rope arm in module 2 and the time and angle history arrays in the glove box lid rotation time solution module in module 5. Based on the time values ​​in the time history array, the program determines the number of frames for animation playback to ensure that there are enough frames to display the animation. The main program will call this function to draw the animation of the entire process of the glove box lid opening.

3. The method for calculating the opening time of a damped glove box in an automobile according to claim 1, characterized in that, The damper includes a housing (1), a pull rope (2), a compression spring (3), a perforation (4), a top cover (5), a shaft (6), and a rubber ring (7). The shaft (6) is slidably installed inside the hollow housing (1). The rubber ring (7) is fixed on the shaft (6), and its outer edge slides against the inner wall of the housing (1). The top cover (5) has a perforation (4) and is fixed to the open end of the housing (1). The two ends of the compression spring (3) abut against the shaft (6) and the top cover (5) respectively. One end of the pull rope (2) protrudes from the top cover (5) into the hollow housing (1), passes through the compression spring (3), and is connected to the shaft (6). The other end is connected to one end of the limiting hook (STc) of the cover (STb). The damper generates buffer damping by the sliding of the shaft (6) and the rubber ring (7) and the elastic force of the elastic spring (3).

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