Rope type unpowered source cabin door assisting mechanism and design method of coiled spring helix thereof

Abstract

The application is a kind of rope type non-power source cabin door assisting mechanism and its coiled spring spiral line design method. The coiled spring is used in the rope type non-power source cabin door assisting mechanism, the assisting mechanism comprises a top cabin door, two groups of hinge force arms, a pulley set assembly and an elastic element assembly; the top cabin door is hinged to a vehicle body through the two groups of hinge force arms, one end of a plastic coated steel wire rope at an output end of the pulley set assembly is connected to the top cabin door, the elastic element assembly adopts N coiled springs, and the design method of the spiral line shape of the coiled spring is as follows: determining the relationship between the contraction length of the plastic coated steel wire rope and the tension; calculating the rope tension of the pulley set; according to the relationship between the total moment of the coiled spring and the rope tension of the pulley set, the relationship between the winding moment of each coiled spring and the curvature radius is obtained; the relationship between the number of rotation of the coiled spring and the cumulative length of the coiled spring is established, and the relationship curve between the curvature radius of the spiral line of the coiled spring at each position and the cumulative length of the coiled spring is calculated. The application realizes the matching of the elastic force in different expansion states and the corresponding cabin door opening stage, and realizes the hovering of the cabin door at any position.

Description

Technical Field

[0001] This invention belongs to the field of coil springs and vehicles, specifically relating to a rope-type non-powered hatch assist mechanism and its coil spring helix design method. Background Technology

[0002] The top hatch is a crucial passageway for special vehicle occupants to perform rapid deployment, emergency evacuation, and external observation missions. Its speed, ease of operation, and reliability directly impact mission success and occupant safety. However, existing top hatch designs still suffer from drawbacks such as the door's weight making opening difficult and the inability to hover at any angle.

[0003] A search of existing technologies revealed that Chinese patent document CN 107355157 A, published on November 17, 2017, discloses a design for a top hatch with a steplessly adjustable opening angle. This design primarily achieves stepless adjustment of the opening and closing angle by adding a ratchet and pawl structure and a guide groove assembly to the hinge. However, this design lacks an assist mechanism, requiring occupants to manually overcome the weight of the hatch when opening it. Chinese patent document CN 209482999 U, published on October 11, 2019, discloses a top hatch opening and closing assist mechanism based on torsion bar coil springs. This mechanism primarily uses two rectangular torsion bar coil springs as energy storage elements to provide assistive force when opening the hatch, making it easier for occupants to open it. However, this design cannot hover at any angle and only provides assistance. Summary of the Invention

[0004] The purpose of this invention is to provide a top hatch elastic element assist mechanism that can hover at any angle and a design method for the spiral shape of the elastic element, so as to achieve the effect of hovering at any angle and opening with only minimal force.

[0005] The technical solution to achieve the purpose of this invention is as follows: a coil spring helical design method, wherein the coil spring is used in a rope-type non-powered hatch assist mechanism. The assist mechanism includes a top hatch, two sets of hinge arms, a pulley assembly and an elastic element assembly disposed between the two sets of hinge arms. The top hatch is hinged to the vehicle body through the two sets of hinge arms. One end of the plastic-coated steel wire rope II at the output end of the pulley assembly is connected to the top hatch. The elastic element assembly uses N coil springs. The design of the coil spring helical shape satisfies the following: when the hatch is at 90° with the vehicle body, the coil spring is in its natural state; when the hatch is at any angle between 0° and 90°, the coil spring is in its working state. The coil spring torque generated by the coil spring is converted into a torque that balances the weight of the hatch through the pulley assembly, causing the hatch to hover. The input of the pulley assembly is the total coil spring torque of the elastic element assembly. The output is a tensile torque that balances the gravitational torque of the hatch; the specific design method for the coil spring helix shape is as follows:

[0006] Step (1): Determine the relationship between the contraction length of the PVC-coated steel wire rope II and the tension of the PVC-coated steel wire rope II;

[0007] Step (2): Calculate the tension of the rope in the pulley system ;

[0008] Step (3): Based on the total torque of the coil spring With pulley system rope tension The relationship is used to obtain the winding torque of each coil spring. With radius of curvature Relationship;

[0009] Step (4): Establish the number of rotations of the coil spring Cumulative length with coil spring The relationship was determined, and the radius of curvature at various points along the coil spring helix was calculated. Cumulative length with coil spring The relationship curve, i.e., the shape of the coiled spring helix.

[0010] Furthermore, the top hatch is equipped with a hatch connector for fixing one end of the plastic-coated steel wire rope II. Step (1) specifically involves:

[0011] A simplified geometric model of the wire rope-hatchway is established. With the hatch closed, point A is marked as the position of the fixed plastic-coated wire rope II on the hatchway connector; point B is marked as the center of the hinge arm pivot; and point C is marked as the contact point between the plastic-coated wire rope II and the fixed pulley I at the output end of the pulley assembly. The distance from the hatchway's center of gravity to the hinge axis is... , for The lever arm of the rope to the hinge is denoted as . When the hatch turns upward At this point, point A has moved to point A'. The length of AC at this time, which is the exposed length of the rope, is denoted as . The lever arm of the rope to the hinge is denoted as . The tensile force of the exposed section of the PVC-coated steel wire rope II is recorded as... ;

[0012] right and Using the law of cosines, we get:

[0013] (1),

[0014] (2),

[0015] right and The area can be expressed using two methods: multiplying the product of the two sides by the sine of the included angle, and multiplying the base by the perpendicular line.

[0016] (3),

[0017] (4),

[0018] By transforming equation (3), we get:

[0019] (5),

[0020] By transforming equation (4), we get:

[0021] (6),

[0022] Furthermore, the gravitational torque of the hatch and the tension torque of the ropes are balanced:

[0023] (7),

[0024] in, For the quality of the hatch, It is the acceleration due to gravity;

[0025] Substituting equation (6) into equation (7), we get:

[0026] (8),

[0027] , , , , , All are known quantities, therefore for each hatch corner The exposed length of the plastic-coated steel wire rope II can be obtained through equations (2), (6), and (8). The lever arm from the rope to the hinge PVC-coated steel wire rope II tensile strength Thus, the tensile strength of the plastic-coated steel wire rope II is obtained. Length of exposed section of PVC coated steel wire rope II The relationship.

[0028] Furthermore, the pulley assembly also includes a plastic-coated steel wire rope I, a fixed pulley II, a movable pulley I, a movable pulley II, and a pulley assembly base. Fixed pulley II, fixed pulley I, and movable pulley II are all connected to the pulley assembly base. One end of the plastic-coated steel wire rope II is connected to the hatch connecting seat, and the other end passes over fixed pulley I and fixed pulley II and is fixed to the end ring of movable pulley I. One end of the plastic-coated steel wire rope I is connected to the terminal block at the output end of the elastic element assembly, and the other end passes over movable pulley I and movable pulley II and is fixed to the rope connecting seat on the inner side of the pulley assembly housing. Movable pulley I and movable pulley II form a 4-fold labor-saving pulley system. Fixed pulley II and fixed pulley I have the same size and specifications, and movable pulley I and movable pulley II have the same size and specifications.

[0029] Furthermore, step (2) specifically involves:

[0030] Plastic-coated steel wire rope II is divided into three sections by two fixed pulleys in the pulley assembly. The tension of the section from the hatch connecting seat to fixed pulley I is denoted as... The tension in section I of fixed pulley II is denoted as . The tension in the section from fixed pulley II to movable pulley I is denoted as . The tension of the section of the plastic-coated steel wire rope I connected to the terminal block is denoted as . ;

[0031] The difference in tension torque between the ropes on both sides of the pulley is the sum of the static friction torque of the pulley and ropes and the dynamic friction torque of the pulley itself. Therefore:

[0032] (9),

[0033] (10),

[0034] (11),

[0035] In the formula, , , These represent the pressure exerted by the plastic-coated steel wire rope on fixed pulley I, fixed pulley II, and movable pulley, respectively. , These are the mid-surface radii of the movable pulley and the fixed pulley, respectively. , These are the pin diameters of the movable pulley and the fixed pulley, respectively. , , The coefficient of static friction between the plastic-coated steel wire rope and fixed pulleys I, II, and the movable pulley is given. , , The coefficient of dynamic friction between the pulley and the pins of fixed pulley I, fixed pulley II, and movable pulley;

[0036] The pressures exerted by the rope on fixed pulley I, fixed pulley II, and movable pulley are respectively:

[0037] (12),

[0038] (13),

[0039] (14),

[0040] The included angle between the ropes at both ends of the fixed pulley I Calculated using the following formula:

[0041] (15),

[0042] In the design, the static friction is assumed to be zero, that is... Then, as long as the error caused by the simplified model is less than the static friction limit, the system can achieve hovering at any position. When the system is hovering, the dynamic friction of the pulley itself is converted into static friction. At this time, equations (9), (10), and (11) are simplified to:

[0043] (16),

[0044] (17),

[0045] (18),

[0046] Combining equations (16)-(18), the tension of the section between fixed pulley I and fixed pulley II is calculated. Tension in the section from fixed pulley II to movable pulley I Pulley system rope tension .

[0047] Furthermore, step (3) specifically involves:

[0048] From the torque balance, the total torque of the coil spring is known With pulley system rope tension The relationship is:

[0049] (19),

[0050] in, The radius of the terminal block;

[0051] Since the elastic element assembly contains N coil springs, and the N coil springs are uniformly stressed, the winding torque of a single coil spring is... for:

[0052] (20),

[0053] Derivation of the winding torque of a coil spring using the strain energy density integral method With radius of curvature Relationship:

[0054] The coil spring is considered as a thin steel sheet initially in a bent state, storing elastic energy as it is rolled into a more bent state; known parameters include: coil spring width. Material elastic modulus Steel sheet thickness The known variables are: the radius of curvature of the coil spring at various points in its initial state. The radius of curvature at each point in the rolled-up state is All of these are functions with the cumulative length s of the coil spring as the independent variable;

[0055] Assume the neutral layer of the coiled spring sheet is at the center of its thickness, and the deformation is within the elastic range; the deformation of the coiled spring sheet is pure bending, and during the bending process, the outermost layer experiences the maximum strain; the coiled spring is gradually tightened from the inner layer to the outer layer, and bending moment only occurs at the winding point of the coiled spring sheet; assume the straightening process is quasi-static; then, using the strain energy formula for bending deformation, consider a infinitesimal element. The curvature in its natural state is The curvature after rolling is Then the increase in strain energy for:

[0056] (twenty one),

[0057] middle, For the flexural stiffness of the section, ;

[0058] The work done by the external torque when winding this infinitesimal element ,in Let be the relative rotation angle between the two cross sections of the infinitesimal element. ;

[0059] Since the deformation process is quasi-static, energy is conserved. ,Right now:

[0060] (twenty two),

[0061] Simplifying, we get:

[0062] (twenty three).

[0063] Furthermore, step (4) specifically involves:

[0064] For calculating the length of the coiled portion of the spring, assume that the spring is gradually tightened from the inner layer to the outer layer and gradually loosened from the inner layer to the outer layer during unwinding, while the total length of the spring remains constant; in the tightened state, the radius of curvature of the spring curve in the cylindrical coordinate system increases uniformly, with each turn increasing the spring thickness. The polar equation of the tightly rolled portion can be written as: Then, the number of rotations of the coil spring is determined by integral calculation. Cumulative length with coil spring Relationship:

[0065] (twenty four)

[0066] Displacement of PVC-coated steel wire rope II along the rope direction:

[0067] (25)

[0068] Because the pulley system is a 4x effort-saving pulley system, the winding length of the plastic-coated steel wire rope I...

[0069] (26)

[0070] The radius of the terminal block fixed to the inner column of the spring frame is The number of rotations of the inner column of the coil spring frame is:

[0071] (27)

[0072] From equations (8), (16)-(18), (20), (23), the cabin door angle Calculate the tensile force of the plastic-coated steel wire rope II. The tension of the plastic-coated steel wire rope II Calculate the rope tension of the pulley system The tension of the ropes in the pulley system Calculate the winding torque of the coil spring Ultimately, it is determined by the winding torque of the coil spring. Calculate the radius of curvature This allows us to solve for the turning angle of each hatch. The radius of curvature of the coil spring below ;

[0073] From equations (1)-(2) and (24)-(27), from the hatch angle Calculate the length of line segment AC and the length of the exposed section of the plastic-coated steel wire rope II ,Depend on , Calculate the displacement of the plastic-coated steel wire rope II along the rope direction. and the winding length of the plastic-coated steel wire rope I ,Depend on Calculate the number of rotations of the inner column of the coil spring. Ultimately, it is determined by the number of rotations of the inner column of the coil spring. Calculate the cumulative length of the coil spring This allows us to solve for the turning angle of each hatch. The cumulative length of the coil spring below ;

[0074] From each hatch corner The radius of curvature of the coil spring below and each cabin door corner The cumulative length of the coil spring below The radius of curvature of the coil spring helix at various points was calculated. Cumulative length with coil spring The relationship curve is the shape of the coiled spring helix.

[0075] A rope-type non-powered hatch assist mechanism includes a top hatch, two sets of hinge arms, a pulley assembly and an elastic element assembly disposed between the two sets of hinge arms; the top hatch is hinged to the vehicle body through the two sets of hinge arms, one end of the plastic-coated steel wire rope II at the output end of the pulley assembly is connected to the top hatch, and the elastic element assembly uses N coil springs, the spiral shape of which is designed by the above method.

[0076] Furthermore, the elastic element assembly also includes a spring frame housing, a spring frame base, and a spring frame inner post.

[0077] The middle section of the coil spring is in a spiral state, and both ends have reverse folding sections;

[0078] One end of the inner column of the coil spring frame is a structure of a frustum and a square boss. The square boss is used to install the terminal block. The side plate of the terminal block has an opening for passing through the plastic-coated steel wire rope I and fixing it as the output end of the elastic element assembly. The other end of the inner column of the coil spring frame is a thin column with N evenly distributed grooves. The depth of the grooves is greater than the length of the inner coil folded section of the coil spring. The thickness and width of the grooves match the inner coil folded section of the coil spring.

[0079] The coil spring frame base is composed of an integrally formed end face, two side plates and multiple partitions. The end face has four grooves evenly distributed around its circumference, and the inner wall of the coil spring frame shell has protrusions that match the grooves. The two side plates are set at 180°, perpendicular to the end face, and the diameter of the circle containing the side plates is smaller than the maximum diameter of the partition. Multiple partitions are spaced apart along the axial direction of the inner column of the coil spring frame. The middle of the partition has a through hole for the thin column of the inner column of the coil spring frame to pass through. Each partition has a notch evenly distributed around its outer circumference that matches the protrusion on the inner wall of the coil spring frame shell.

[0080] The partition separates the N coil springs. The inner coil of each coil spring is inserted into the groove of the thin column, and the outer coil spring is fastened to the side plate on the same side of the coil spring frame base. When the coil spring releases its elastic force, it drives the inner column of the coil spring frame to rotate.

[0081] Furthermore, the pulley assembly also includes a pulley assembly cover;

[0082] The pulley assembly base is an open box shape with a circular hole and a countersunk hole on one side for mounting the elastic element assembly; side plates with threaded holes extend from both sides of the bottom of the base for fixing to the vehicle body;

[0083] The lower part of the pulley assembly cover is symmetrically provided with side plates with threaded holes, which form a closed and stable overall structure after being assembled with the pulley assembly base;

[0084] The tail rings of fixed pulley II, fixed pulley I and movable pulley II are inserted into a slender fixed plate, and the two ends of the fixed plate are connected to the base of the pulley assembly by bolts;

[0085] One end of the plastic-coated steel wire rope II is connected to the hatch connecting seat, and the other end passes through the fixed pulley I and fixed pulley II in sequence and is fixed to the end ring of the movable pulley I with a locking device. The movable pulley I and the movable pulley II form a 4-fold labor-saving pulley group. One end of the plastic-coated steel wire rope I is connected to the terminal block at the output end of the elastic element, and the other end is fixed to the rope connecting seat on the inner side of the pulley group assembly housing.

[0086] Furthermore, it also includes hinge bases and vehicle body connecting seats;

[0087] The vehicle body connecting seat is fixed to the vehicle body. The hinge base is fixed to the vehicle body connecting seat by bolts. One end of the hinge lever arm is hinged to the hinge base by a pin perpendicular to the main body of the hinge lever arm. The other end of the hinge lever arm is provided with a small side plate and threaded holes, and is connected to the top hatch by bolts. The hatch connecting seat includes a base plate and a vertical plate. The base plate has threaded holes at the four corners and is fixed to the hatch by bolts. The vertical plate is drilled to allow the plastic-coated steel wire rope II to pass through. After the plastic-coated steel wire rope II passes through the hole, it is fixed with a wire lock.

[0088] Compared with the prior art, the significant advantages of this invention are:

[0089] This invention utilizes the elastic element assembly to output driving force to the pulley assembly, which then acts on the hatch, thus assisting in opening the top hatch and significantly reducing the external force required for occupants to open it. Simultaneously, the relationship between rope tension and rope retraction distance is derived using the geometric positional relationship of the mechanism; the dynamic friction of the pulleys and the static friction between the pulleys and ropes are introduced, and the relationship between rope tension and coil spring winding torque is obtained by combining the pulley assembly's force-saving factor and the outer diameter of the terminal block; the relationship between coil spring winding torque and radius of curvature is derived using the "strain energy density integration method." Furthermore, the relationship curves between the radius of curvature at various points on the coil spring and the cumulative length of the coil spring are integrated and calculated, characterizing the helical shape of the elastic element. Through customized processes, coil springs adapted to the hatch opening stage can be obtained, achieving matching of elastic force in different deployment states with the corresponding hatch opening stage. Static friction acts as a margin and balances the system, enabling the hatch to hover at any position. Attached Figure Description

[0090] Figure 1 This is a schematic diagram of the external appearance of the power-free hatch elastic element assist mechanism of the present invention.

[0091] Figure 2 This is a schematic diagram of the elastic element assembly structure of the present invention.

[0092] Figure 3 This is a schematic diagram of the inner column structure of the coil spring frame of the present invention.

[0093] Figure 4 This is a schematic diagram of the pulley block assembly structure of the present invention.

[0094] Figure 5 This is a schematic diagram of the pulley block connection method of the present invention.

[0095] Figure 6 This is a simplified schematic diagram of the door movement of the present invention.

[0096] Figure 7 This is a schematic diagram of the coil spring winding of the present invention.

[0097] Figure 8 The tensile strength of the plastic-coated steel wire rope II in this embodiment of the invention. A graph showing the relationship between the exposed length c of the plastic-coated steel wire rope II.

[0098] Figure 9 This is a graph showing the relationship between the cumulative length S of the coil spring's point of action and the door rotation angle α in an embodiment of the present invention.

[0099] Figure 10 This is a graph showing the relationship between the radius of curvature r of the coil spring's point of action and the door rotation angle α in an embodiment of the present invention.

[0100] Figure 11This is a graph showing the relationship between the radius of curvature r of the coil spring curve at various points in the initial state of this invention and the cumulative length S of the coil spring.

[0101] Explanation of reference numerals in the attached figures:

[0102] 1-Top hatch, 2-Hatch door connecting seat, 3-Hinge lever arm, 4-Hinge base, 5-Body connecting seat, 6-Pulley assembly, 7-Elastic element assembly, 8-Spring frame housing, 9-Connecting terminal, 10-Spring frame base, 11-Spring frame inner column, 12-Plastic coated steel wire rope I, 13-Plastic coated steel wire rope II, 14-Fixed pulley I, 15-Fixed pulley II, 16-Moving pulley I, 17-Moving pulley II, 18-Pulley assembly cover, 19-Pulley assembly base, 20-Rope connecting terminal, 21-Spring. Detailed Implementation

[0103] The present invention will now be described in further detail with reference to the accompanying drawings.

[0104] A non-powered hatch elastic element assist mechanism, which mainly includes a hinge arm, a hinge base, a vehicle body connecting seat, a hatch connecting seat, a pulley assembly, and an elastic element assembly.

[0105] When the top hatch is open at 90 degrees, the elastic element is in its natural state. When the top hatch closes, the elastic element begins to store energy, reaching its peak energy level when the hatch closes. Based on formulas such as torque balance and strain energy density integration, the radius of curvature and cumulative length of the coil spring at a specific hatch angle are derived. This allows for precise control of the radius of curvature at different positions of the elastic element through stretching, thus obtaining suitable tension values ​​for different locations. When the hatch needs to be opened, only a small external force is required to overcome friction to move it. After removing this external force, the hatch enters a hovering state.

[0106] The pulley assembly consists of a pulley assembly cover 18, a pulley assembly base 19, fixed pulley I 14, fixed pulley II 15, movable pulley I 16, movable pulley II 17, and two sections of plastic-coated steel wire rope. The plastic-coated steel wire rope, connected to the output end of the elastic element assembly, alternately wraps around movable pulley I 16 and movable pulley II 17, ultimately connecting to a rope connector fixed to the inner side of the pulley assembly housing, forming a 4x effort-saving pulley system. One end of the other plastic-coated steel wire rope is fixed to the end ring of movable pulley I 16, then sequentially wraps around fixed pulley I 15 and fixed pulley II 16, leading to the hatch connector for fixation. Fixed pulley I 15, fixed pulley II 16, and movable pulley II 17 are all connected to the pulley assembly base via end rings. The right side of the pulley assembly base has a circular opening and countersunk holes with evenly distributed threaded holes for mounting the elastic element assembly.

[0107] The elastic element assembly consists of an inner column 11 of the spring frame, a spring frame base 10, a spring frame outer shell 8, a terminal block 9, and six variable-force springs. When the inner column of the spring frame rotates relative to the spring frame base, it needs to overcome the deformation energy of the springs to do work, and the springs begin to store energy. The spring frame base has four axial grooves on the outer circumference of its end face, and the inside of the spring frame outer shell has protrusions that match the grooves for fixing the spring frame. The side of the spring frame outer shell near the output end of the elastic element has evenly distributed threaded holes for fixing the spring frame to the pulley assembly base. The terminal block is installed on the inner column of the spring frame, and the side plate of the terminal block has a circular opening for passing through and fixing a plastic-coated steel wire rope.

[0108] A power-source-free hatch elastic element assist mechanism and its design method for the spiral shape of the elastic element, the assist mechanism having the following appearance: Figure 1 As shown. The powerless hatch elastic element assist mechanism includes a hinge arm 3, a hinge base 4, a vehicle body connecting seat 5, a hatch connecting seat 2, a pulley assembly 6, and an elastic element assembly 7.

[0109] The body connecting seat 5 is welded to the body. The hinge base 4 is fixed to the body connecting seat 5 by bolts. One end of the hinge arm 3 is provided with a pin perpendicular to the body of the hinge arm and is hinged to the hinge base 5. The other end of the hinge arm 3 is provided with a small side plate and threaded holes, and is connected to the hatch 1 by bolts. The hatch connecting seat 2 can be regarded as a base plate plus a vertical plate. The base plate has threaded holes at the four corners to fix it to the lower middle part of the hatch by bolts. The vertical plate is drilled with holes for the plastic-coated steel wire rope II13 to pass through. The plastic-coated steel wire rope II13 of the pulley assembly 6 passes through the holes and is fixed with a cable lock. The bottom of the pulley assembly 6 is fixed to the body by bolts. The elastic element assembly 7 is fixed to the right side of the pulley assembly 6 by bolts. The elastic element assembly 7 uses N coil springs. When the hatch is at 90° to the vehicle body, the coil springs are in their natural state. When the hatch is at any angle between 0° and 90°, the coil springs are in their working state. The coil spring torque generated by the coil springs is converted into a torque that balances the weight of the hatch through the pulley assembly, causing the hatch to hover. The spiral shape of the coil springs is obtained by calculating the radius of curvature of the coil springs that balances the weight of the hatch at any turning angle. Cumulative length of coil spring The radius of curvature of the coil spring was obtained when the hatch angle was 0-90°. Cumulative length of coil spring The relationship (i.e., the shape of the coil spring helix).

[0110] The elastic element assembly 7 includes a spring frame inner post 11, a spring frame base 10, a spring frame outer shell 8, a terminal block 9, and N variable force springs. The springs, spring frame inner post 11, spring frame base 10, and spring frame outer shell 8 are as follows: Figure 2As shown in the assembly, the coil spring frame base 10 has four axial grooves on the outer periphery of its end face, and the coil spring frame housing 8 has protrusions inside that match the grooves for fixing the coil spring frame. The structure of the inner column 11 of the coil spring frame is as follows: Figure 3 As shown, the left end has a frustum and a square boss structure. The square boss is used to install the terminal block 9. Both the square boss and the terminal block 9 have transverse through holes for inserting limit pins to restrict axial displacement. The side plate of the terminal block 9 has an opening for passing through and fixing the plastic-coated steel wire rope I12 as the output end of the elastic element assembly 7. The right side has a thin column with N evenly distributed grooves for fixing coil springs. The thin column of the coil spring frame is coaxially inserted into the coil spring frame base 10. The coil spring frame base 10 has N partitions to separate N coil springs, and two symmetrical side plates. The middle section of the coil spring is in a spiral state, and both ends are bent back. The inner coil of each coil spring is bent back to be inserted into the groove of the thin column for fixing, and the outer coil of each coil spring is bent back to be fastened to the side plate on the same side of the coil spring frame base 10 for fixing. Figure 2 As shown on the right. Thus, when the coil spring releases its elastic force, it can drive the inner column 11 of the coil spring frame to rotate.

[0111] The pulley block assembly 6 is a transmission mechanism consisting of a pulley block assembly cover 18, a pulley block assembly base 19, fixed pulley I 14, fixed pulley II 15, movable pulley I 16, movable pulley II 17, plastic-coated steel wire rope I 12, and plastic-coated steel wire rope II 13. Its structure is as follows: Figure 4 As shown.

[0112] The assembly's housing features a split design. A circular hole and countersunk hole are located on one side of the base for mounting the elastic element assembly 7. Threaded side plates extend from both sides of the base's bottom for reliable fixation to the vehicle body. Threaded side plates are symmetrically arranged at the bottom of the pulley assembly cover 18, forming a closed and stable integrated structure when assembled with the pulley assembly base 19. The pulleys are fixed as follows: the tail rings of fixed pulleys II 15, I 14, and II 17 are inserted into a slender fixing plate. The two ends of the fixing plate are connected to the pulley assembly base 19 by bolts, ensuring the pulleys' positional stability during operation. Furthermore, the fixed pulleys of this assembly have a diameter of 20mm, and the movable pulleys have a diameter of 32mm.

[0113] In terms of transmission and force application, the input of the pulley assembly 6 is the total torque of the coil springs in the elastic element assembly 7. The output is a pulling torque that balances the gravitational torque of hatch 1. One end of the plastic-coated steel wire rope II13 is connected to the hatch connecting seat 2, and the other end passes through the fixed pulleys II15 and I14 in sequence and is fixed to the end ring of the movable pulley I16 using a locking device. This can change the point of application and direction of the pulling force indirectly acting on the hatch through the hatch connecting seat, while increasing the pulling arm and optimizing the output characteristics of the pulling torque. Movable pulleys I16 and II17 form a 4-fold effort-saving pulley system. One end of the plastic-coated steel wire rope I12 is connected to the terminal block at the output end of the elastic element, and the other end is fixed to the rope connecting seat 20 on the inner side of the pulley assembly housing (e.g., Figure 5 As shown, the total torque of the input coil spring can be efficiently converted into the tension of the plastic-coated steel wire rope I12 of the movable pulley block, and then into the tension of the plastic-coated steel wire rope II13 of the fixed pulley assembly, forming the output tension torque; by taking advantage of the labor-saving characteristics of the movable pulley block, the input load required for opening and closing the hatch is greatly reduced, and a precise balance with the hatch gravity torque is achieved.

[0114] The core functions of the pulley assembly 6 are mainly reflected in three aspects: First, the torque transmission and adjustment function, which receives the total torque of the coil spring of the elastic element assembly 7, changes the point of application and direction of the pulling force through the fixed pulley assembly, and optimizes the characteristics of the output pulling torque by increasing the lever arm, thereby achieving a balance with the gravity torque of the hatch; Second, the labor-saving and efficiency-enhancing function, which utilizes the 4-fold labor-saving pulley assembly to significantly reduce the input torque required to drive the hatch opening and closing, thereby improving the transmission efficiency of the mechanism; Third, the structural bearing and integration function, which, through the split shell design, achieves the integrated installation of the elastic elements and the reliable fixation of the assembly and the vehicle body, ensuring the stability and reliability of the overall mechanism operation.

[0115] Design method of helical shape of elastic element

[0116] (1): Determine the relationship between the rope contraction length and the tension.

[0117] First, a simplified geometric model of the wire rope-hatch door is established, such as... Figure 6 As shown in the diagram, the cuboid on the left represents the hatch, and the small circle within it indicates the hatch's center of gravity. Point A is the location where the plastic-coated steel wire rope II13 is fixed on the hatch connecting seat. Point B is the axis of the hatch hinge. Point C is the contact point between the plastic-coated steel wire rope II13 and the fixed pulley I14 (since the radius of the fixed pulley is much smaller than the exposed length of the rope, this is simplified to a point contact between the rope and the pulley, and the contact point position remains unchanged). All of the above positions represent the hatch in the closed state, and the length of line segment BC at this time is denoted as... The length of line segment AB is denoted as The length of line segment AC is denoted as The distance from the center of gravity of the hatch to the hinge axis of the hatch is , for The lever arm from the rope to the hinge is denoted as . (That is, the distance from B to AC). When the hatch rotates upwards... At this point, point A has moved to point A', and the length of AC at this time (i.e., the exposed length of the rope) is denoted as... The lever arm from the rope to the hinge is denoted as . The tensile strength of the exposed section of the PVC-coated steel wire rope II13 is recorded as... .

[0118] right and Using the law of cosines, we can obtain:

[0119] (1)

[0120] (2)

[0121] right and The area can be expressed using two methods: multiplying the product of the two sides by the sine of the included angle, and multiplying the base by the perpendicular line. We can obtain:

[0122] (3)

[0123] (4)

[0124] By transforming equation (3), we can obtain:

[0125] (5)

[0126] By transforming equation (4), we can obtain:

[0127] (6)

[0128] Furthermore, the gravitational torque of the hatch and the tension torque of the ropes are balanced:

[0129] (7)

[0130] in, For the quality of the hatch, This is the acceleration due to gravity.

[0131] Substituting equation (6) into equation (7), we get:

[0132] (8)

[0133] , , , , , All are known quantities, therefore for each hatch corner The exposed length of the plastic-coated steel wire rope II13 can be obtained through equations (2), (6), and (8). The lever arm from the rope to the hinge Plastic-coated steel wire rope II13 tensile strength Thus, the tensile strength of the PVC-coated steel wire rope II13 can be obtained. Length of exposed section of PVC coated steel wire rope II13 Relationships, such as Figure 6 As shown.

[0134] (2): Calculate the rope tension of the pulley system

[0135] Plastic-coated steel wire rope II13 can be considered as being divided into three sections by two fixed pulleys. The tension from the hatch connecting seat to one end of fixed pulley I14 is denoted as... The tension of the section between fixed pulley I14 and fixed pulley II15 is denoted as The tension in the section from fixed pulley II15 to movable pulley I16 is denoted as The tension of the section where the plastic-coated steel wire rope I12 connects to the spring frame terminal block is denoted as... .

[0136] The difference in tension torque between the ropes on both sides of the pulley is the sum of the static friction torque of the pulley and ropes and the dynamic friction torque of the pulley itself. Therefore:

[0137] (9)

[0138] (10)

[0139] (11)

[0140] In the formula, , , These are the pressures exerted by the ropes on fixed pulley I14, fixed pulley II15, and movable pulley, respectively. , These are the mid-surface radii of the movable pulley and the fixed pulley, respectively. , These are the pin diameters of the movable pulley and the fixed pulley, respectively. , , The static friction coefficient between the plastic-coated steel wire rope and the pulley is taken as 0.4; , , The coefficient of dynamic friction between the pulley and the pin is 0.15.

[0141] The pressure of the rope on the pulley is:

[0142] (12)

[0143] (13)

[0144] (14)

[0145] In the formula, Let the included angle between the ropes at both ends of the fixed pulley I14 be taken as... Figure 6 middle Size, The magnitude can be calculated using the law of cosines:

[0146] (15)

[0147] In the design, the static friction is assumed to be zero, that is... If the error caused by the simplified model is less than the limit of static friction, the system can be hovered at any position. When the system is hovering, the dynamic friction of the pulley itself is converted into static friction. The static friction between the pulley and the rope acts as a margin and balance system.

[0148] At this point, equations (9), (10), and (11) simplify to:

[0149] (16)

[0150] (17)

[0151] (18)

[0152] Combining equations (16)-(18), the tension of a section between fixed pulley I14 and fixed pulley II15 can be calculated sequentially. The tension in the section from fixed pulley II15 to movable pulley I16 Pulley system rope tension That is, the tension of the rope in the pulley system is obtained. .

[0153] (3): Based on the total torque of the coil spring With pulley system rope tension The relationship is used to derive the winding torque of the coil spring. Its radius of curvature Relationship

[0154] According to the torque balance, the total torque of the coil spring is... With tension of PVC coated steel wire rope I12 The relationship is:

[0155] (19)

[0156] in, The radius of the terminal block.

[0157] Since the elastic element assembly contains N coil springs, and the N coil springs are uniformly stressed, the winding torque of a single coil spring is... for:

[0158] (20)

[0159] Derivation of the winding torque of a coil spring using the strain energy density integral method Its radius of curvature Relationship:

[0160] The coil spring can be viewed as a thin sheet of steel originally in a bent state, storing elastic energy as it is rolled into an even more bent state. Known parameters include: coil spring width. Material elastic modulus Steel sheet thickness The known variables are: the radius of curvature of the coil spring at various points in its initial state. The radius of curvature at each point in the rolled-up state is Both are functions with the cumulative length s of the coil spring as the independent variable.

[0161] Simplifications and assumptions are made: the neutral layer of the coil spring steel sheet is at the center of the thickness, and the deformation is within the elastic range; the deformation of the coil spring steel sheet is mainly pure bending, and during the bending process, the outermost fiber experiences the maximum strain; the coil spring is gradually wound from the inner layer to the outer layer, and there is a bending moment only at the winding point of the coil spring steel sheet; the straightening process is assumed to be quasi-static.

[0162] Based on the strain energy formula for bending deformation, consider a infinitesimal element. The curvature in its natural state is The curvature after rolling is Then the increase in strain energy for:

[0163] (twenty one)

[0164] in, For the flexural stiffness of the section, .

[0165] The increase in strain energy is provided by the work done by the winding torque, which is the work done by the external torque when winding this infinitesimal element. ,in Let be the relative rotation angle between the two cross sections of the infinitesimal element. .

[0166] Since the deformation process is quasi-static, energy is conserved. ,Right now:

[0167] (twenty two)

[0168] Simplifying, we get:

[0169] (twenty three)

[0170] (4): Establish the number of rotations of the coil spring Cumulative length with coil spring The relationship was determined, and the radius of curvature at various points along the coil spring helix was calculated. Cumulative length with coil spring Relationship curve

[0171] For calculating the length of the coiled portion of the spring, it is assumed that the spring is gradually tightened from the inner layer to the outer layer, and gradually loosened from the inner layer to the outer layer during unwinding, while the total length of the spring remains constant; in the tightened state, the radius of curvature of the spring curve in the cylindrical coordinate system increases uniformly, with each turn increasing the spring thickness. Then the polar coordinate equation of the tightly rolled part can be written as: The number of rotations of the coil spring can then be determined by integral calculation. Cumulative length with coil spring Relationship:

[0172] (twenty four)

[0173] Displacement of PVC-coated steel wire rope II13 along the rope direction:

[0174] (25)

[0175] Because the pulley system is a 4x effort-saving pulley system, the winding length of the plastic-coated steel wire rope I12 is...

[0176] (26)

[0177] The radius of the terminal block fixed to the inner column of the spring frame is The number of rotations of the inner column of the coil spring frame is:

[0178] (27)

[0179] From equations (8), (16)-(18), (20), and (23), it can be determined by the hatch corner. Calculate the tensile force of the PVC-coated steel wire rope II13. The tensile strength is provided by PVC-coated steel wire rope II13. Calculate the rope tension of the pulley system The tension of the ropes in the pulley system Calculate the winding torque of the coil spring Ultimately, it is determined by the winding torque of the coil spring. Calculate the radius of curvature This allows us to solve for the turning angle of each hatch. The radius of curvature of the coil spring below .

[0180] From equations (1)-(2) and (24)-(27), the angle of the hatch can be determined. Calculate the length of line segment AC and the length of the exposed section of the PVC-coated steel wire rope II13 ,Depend on , Calculate the displacement of the plastic-coated steel wire rope II13 along the rope direction. and the winding length of the plastic-coated steel wire rope I12 ,Depend on Calculate the number of rotations of the inner column of the coil spring. Ultimately, it is determined by the number of rotations of the inner column of the coil spring. Calculate the cumulative length of the coil spring This allows us to solve for the turning angle of each hatch. The cumulative length of the coil spring below .

[0181] From each hatch corner The radius of curvature of the coil spring below and each cabin door corner The cumulative length of the coil spring below The radius of curvature at various points along the coil spring helix can be calculated. Cumulative length with coil spring The relationship curve (i.e., the shape of the coil spring helix).

[0182] Example

[0183] In this embodiment, the relevant structural parameters and physical coefficients are as follows: , , , , , , , , , , , , , , , , N=6.

[0184] In this embodiment, MATLAB is used to solve for the relationship curve between r and S. The parameters from the previous embodiment are assigned as constants to the corresponding variables, including the hatch rotation angle. The angle is taken as 0~90°, with a step size of 0.1°. The rotation angle of each hatch is solved by equations (8), (16)-(18), (20), and (23). The radius of curvature of the coil spring below The rotation angle of each hatch is solved by equations (1)-(2) and (24)-(27). The cumulative length of the coil spring below ,like Figure 9 , 10 As shown, the final curve relating r and S is obtained, as follows: Figure 11 As shown, the helical shape of this elastic element can be characterized. Then, a customized coil spring adapted to this mechanism is obtained through a customized process to achieve arbitrary angle hovering of the hatch.

[0185] The above description is merely an embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for designing a coiled spring helical wire, characterized in that, The coil springs are used in the rope-type, non-powered hatch assist mechanism. The assist mechanism includes a top hatch, two sets of hinge arms, a pulley assembly positioned between the two sets of hinge arms, and an elastic element assembly. The top hatch is hinged to the vehicle body via the two sets of hinge arms. One end of the plastic-coated steel wire rope II at the output end of the pulley assembly is connected to the top hatch. The elastic element assembly uses N coil springs. The spiral shape of the coil springs is designed to ensure that: when the hatch is at 90° to the vehicle body, the coil springs are in their natural state; when the hatch is at any angle between 0° and 90°, the coil springs are in their working state. The coil spring torque generated by the coil springs is converted by the pulley assembly into a torque that balances the weight of the hatch, causing the hatch to hover. The input to the pulley assembly is the total coil spring torque of the elastic element assembly. The output is a tensile torque that balances the gravitational torque of the hatch; the specific design method for the coil spring helix shape is as follows: Step (1): Determine the relationship between the contraction length of the PVC-coated steel wire rope II and the tension of the PVC-coated steel wire rope II; Step (2): Calculate the tension of the rope in the pulley system ; Step (3): Based on the total torque of the coil spring With pulley system rope tension The relationship is used to obtain the winding torque of each coil spring. With radius of curvature Relationship; Step (4): Establish the number of rotations of the coil spring Cumulative length with coil spring The relationship was determined, and the radius of curvature at various points along the coil spring helix was calculated. Cumulative length with coil spring The relationship curve, i.e., the shape of the coiled spring helix.

2. The method according to claim 1, characterized in that, The top hatch is equipped with a hatch connector for fixing one end of the plastic-coated steel wire rope II. Step (1) is as follows: A simplified geometric model of the wire rope-hatchway is established. With the hatch closed, point A is marked as the position of the fixed plastic-coated wire rope II on the hatchway connector; point B is marked as the center of the hinge arm pivot; and point C is marked as the contact point between the plastic-coated wire rope II and the fixed pulley I at the output end of the pulley assembly. The distance from the hatchway's center of gravity to the hinge axis is... , for The lever arm of the rope to the hinge is denoted as . When the hatch turns upward At this point, point A has moved to point A'. The length of AC at this time, which is the exposed length of the rope, is denoted as . The lever arm of the rope to the hinge is denoted as . The tensile force of the exposed section of the PVC-coated steel wire rope II is recorded as... ; right and Using the law of cosines, we get: (1)， (2)， right and The area can be expressed using two methods: multiplying the product of the two sides by the sine of the included angle, and multiplying the base by the perpendicular line. (3)， (4)， By transforming equation (3), we get: (5)， By transforming equation (4), we get: (6)， Furthermore, the gravitational torque of the hatch and the tension torque of the ropes are balanced: (7)， in, For the quality of the hatch, It is the acceleration due to gravity; Substituting equation (6) into equation (7), we get: (8)， , , , , , All are known quantities, therefore for each hatch angle The exposed length of the plastic-coated steel wire rope II can be obtained through equations (2), (6), and (8). The lever arm from the rope to the hinge PVC-coated steel wire rope II tensile strength Thus, the tensile strength of the plastic-coated steel wire rope II is obtained. Length of exposed section of PVC coated steel wire rope II The relationship.

3. The method according to claim 2, characterized in that, The pulley assembly also includes a plastic-coated steel wire rope I, a fixed pulley II, a movable pulley I, a movable pulley II, and a pulley assembly base. Fixed pulley II, fixed pulley I, and movable pulley II are all connected to the pulley assembly base. One end of the plastic-coated steel wire rope II is connected to the hatch connecting seat, and the other end passes over fixed pulley I and fixed pulley II and is fixed to the end ring of movable pulley I. One end of the plastic-coated steel wire rope I is connected to the terminal block at the output end of the elastic element assembly, and the other end passes over movable pulley I and movable pulley II and is fixed to the rope connecting seat on the inner side of the pulley assembly housing. Movable pulley I and movable pulley II form a 4-fold effort-saving pulley system. Fixed pulley II and fixed pulley I have the same size and specifications, and movable pulley I and movable pulley II have the same size and specifications.

4. The method according to claim 3, characterized in that, Step (2) is as follows: Plastic-coated steel wire rope II is divided into three sections by two fixed pulleys in the pulley assembly. The tension of the section from the hatch connecting seat to fixed pulley I is denoted as... The tension in section I of fixed pulley II is denoted as . The tension in the section from fixed pulley II to movable pulley I is denoted as . The tension of the section of the plastic-coated steel wire rope I connected to the terminal block is denoted as . ; The difference in tension torque between the ropes on both sides of the pulley is the sum of the static friction torque of the pulley and ropes and the dynamic friction torque of the pulley itself. Therefore: (9)， (10)， (11)， In the formula, , , These represent the pressure exerted by the plastic-coated steel wire rope on fixed pulley I, fixed pulley II, and movable pulley, respectively. , These are the mid-surface radii of the movable pulley and the fixed pulley, respectively. , These are the pin diameters of the movable pulley and the fixed pulley, respectively. , , The coefficient of static friction between the plastic-coated steel wire rope and fixed pulleys I, II, and the movable pulley is given. , , The coefficient of dynamic friction between the pulley and the pins of fixed pulley I, fixed pulley II, and movable pulley; The pressures exerted by the rope on fixed pulley I, fixed pulley II, and movable pulley are respectively: (12)， (13)， (14)， The included angle between the ropes at both ends of the fixed pulley I Calculated using the following formula: (15)， In the design, the static friction is assumed to be zero, that is... Then, as long as the error caused by the simplified model is less than the static friction limit, the system can achieve hovering at any position. When the system is hovering, the dynamic friction of the pulley itself is converted into static friction. At this time, equations (9), (10), and (11) are simplified to: (16)， (17)， (18)， Combining equations (16)-(18), the tension of the section between fixed pulley I and fixed pulley II is calculated. Tension in the section from fixed pulley II to movable pulley I Pulley system rope tension .

5. The method according to claim 4, characterized in that, Step (3) is as follows: From the torque balance, the total torque of the coil spring is known With pulley system rope tension The relationship is: (19)， in, The radius of the terminal block; Since the elastic element assembly contains N coil springs, and the N coil springs are evenly stressed, the winding torque of a single coil spring is... for: (20)， Derivation of the winding torque of a coil spring using the strain energy density integral method With radius of curvature Relationship: The coil spring is considered as a thin steel sheet initially in a bent state, storing elastic energy as it is rolled into a more bent state; known parameters include: coil spring width. Material elastic modulus Steel sheet thickness The known variables are: the radius of curvature of the coil spring at various points in its initial state. The radius of curvature at each point in the tightly wound state is All of these are functions with the cumulative length s of the coil spring as the independent variable; Assume the neutral layer of the coiled spring sheet is at the center of its thickness, and the deformation is within the elastic range; the deformation of the coiled spring sheet is pure bending, and during the bending process, the outermost layer experiences the maximum strain; the coiled spring is gradually tightened from the inner layer to the outer layer, and bending moment only occurs at the winding point of the coiled spring sheet; assume the straightening process is quasi-static; then, using the strain energy formula for bending deformation, consider a infinitesimal element. The curvature in its natural state is The curvature after rolling is Then the increase in strain energy for: (21)， middle, For the flexural stiffness of the section, ; The work done by the external torque when winding this infinitesimal element ,in Let be the relative rotation angle between the two ends of the infinitesimal element. ; Since the deformation process is quasi-static, energy is conserved. ,Right now: (22)， Simplifying, we get: (23)。 6. The method according to claim 5, characterized in that, Step (4) is as follows: For calculating the length of the coiled portion of the spring, assume that the spring is gradually tightened from the inner layer to the outer layer and gradually loosened from the inner layer to the outer layer during unwinding, while the total length of the spring remains constant; in the tightened state, the radius of curvature of the spring curve in the cylindrical coordinate system increases uniformly, with each turn increasing the spring thickness. The polar equation of the tightly rolled portion can be written as: Then, the number of rotations of the coil spring is determined by integral calculation. Cumulative length with coil spring Relationship: (24) Displacement of PVC-coated steel wire rope II along the rope direction: (25) Because the pulley system is a 4x effort-saving pulley system, the winding length of the plastic-coated steel wire rope I... (26) The radius of the terminal block fixed to the inner column of the spring frame is The number of rotations of the inner column of the coil spring frame is: (27) From equations (8), (16)-(18), (20), (23), the cabin door angle Calculate the tensile force of the plastic-coated steel wire rope II. The tension of the plastic-coated steel wire rope II Calculate the rope tension of the pulley system The tension of the ropes in the pulley system Calculate the winding torque of the coil spring Ultimately, it is determined by the winding torque of the coil spring. Calculate the radius of curvature This allows us to solve for the turning angle of each hatch. The radius of curvature of the coil spring below ; From equations (1)-(2) and (24)-(27), from the hatch angle Calculate the length of line segment AC and the length of the exposed section of the plastic-coated steel wire rope II ,Depend on , Calculate the displacement of the plastic-coated steel wire rope II along the rope direction. and the winding length of the plastic-coated steel wire rope I ,Depend on Calculate the number of rotations of the inner column of the coil spring. Ultimately, it is determined by the number of rotations of the inner column of the coil spring. Calculate the cumulative length of the coil spring This allows us to solve for the turning angle of each hatch. The cumulative length of the coil spring below ; From each hatch corner The radius of curvature of the coil spring below and each cabin door corner The cumulative length of the coil spring below The radius of curvature of the coil spring helix at various points was calculated. Cumulative length with coil spring The relationship curve is the shape of the coiled spring helix.

7. A rope-type non-powered hatch assist mechanism, characterized in that, It includes a top hatch, two sets of hinge arms, a pulley assembly and an elastic element assembly disposed between the two sets of hinge arms; the top hatch is hinged to the vehicle body through the two sets of hinge arms, one end of the plastic-coated steel wire rope II at the output end of the pulley assembly is connected to the top hatch, and the elastic element assembly uses N coil springs, the spiral shape of which is designed according to the method described in any one of claims 1-6.

8. The assist mechanism according to claim 7, characterized in that, The elastic element assembly also includes a spring carrier housing, a spring carrier base, and a spring carrier inner post. The middle section of the coil spring is in a spiral state, and both ends have reverse folding sections; One end of the inner column of the coil spring frame is a structure of a frustum and a square boss. The square boss is used to install the terminal block. The side plate of the terminal block has an opening for passing through the plastic-coated steel wire rope I and fixing it as the output end of the elastic element assembly. The other end of the inner column of the coil spring frame is a thin column with N evenly distributed grooves. The depth of the grooves is greater than the length of the inner coil folded section of the coil spring. The thickness and width of the grooves match the inner coil folded section of the coil spring. The coil spring frame base is composed of an integrally formed end face, two side plates and multiple partitions. The end face has four grooves evenly distributed around its circumference, and the inner wall of the coil spring frame shell has protrusions that match the grooves. The two side plates are set at 180°, perpendicular to the end face, and the diameter of the circle containing the side plates is smaller than the maximum diameter of the partition. Multiple partitions are spaced apart along the axial direction of the inner column of the coil spring frame. The middle of the partition has a through hole for the thin column of the inner column of the coil spring frame to pass through. Each partition has a notch evenly distributed around its outer circumference that matches the protrusion on the inner wall of the coil spring frame shell. The partition separates the N coil springs. The inner coil of each coil spring is inserted into the groove of the thin column, and the outer coil spring is fastened to the side plate on the same side of the coil spring frame base. When the coil spring releases its elastic force, it drives the inner column of the coil spring frame to rotate.

9. The assist mechanism according to claim 8, characterized in that, The pulley block assembly also includes a pulley block assembly cover; The pulley assembly base is an open box shape with a circular hole and a countersunk hole on one side for mounting the elastic element assembly; side plates with threaded holes extend from both sides of the bottom of the base for fixing to the vehicle body; The lower part of the pulley assembly cover is symmetrically provided with side plates with threaded holes, which form a closed and stable overall structure after being assembled with the pulley assembly base; The tail rings of fixed pulley II, fixed pulley I and movable pulley II are inserted into a slender fixed plate, and the two ends of the fixed plate are connected to the base of the pulley assembly by bolts; One end of the plastic-coated steel wire rope II is connected to the hatch connecting seat, and the other end passes through the fixed pulley I and fixed pulley II in sequence and is fixed to the end ring of the movable pulley I with a locking device. The movable pulley I and the movable pulley II form a 4-fold labor-saving pulley group. One end of the plastic-coated steel wire rope I is connected to the terminal block at the output end of the elastic element, and the other end is fixed to the rope connecting seat on the inner side of the pulley group assembly housing.

10. The assist mechanism according to claim 9, characterized in that, It also includes hinge bases and body connection seats; The vehicle body connecting seat is fixed to the vehicle body. The hinge base is fixed to the vehicle body connecting seat by bolts. One end of the hinge lever arm is hinged to the hinge base by a pin perpendicular to the main body of the hinge lever arm. The other end of the hinge lever arm is provided with a small side plate and threaded holes, and is connected to the top hatch by bolts. The hatch connecting seat includes a base plate and a vertical plate. The base plate has threaded holes at the four corners and is fixed to the hatch by bolts. The vertical plate is drilled to allow the plastic-coated steel wire rope II to pass through. After the plastic-coated steel wire rope II passes through the hole, it is fixed with a wire lock.

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