Buffering uniform-load two-dimensional wheel set and rigidity configuration method thereof

Abstract

The invention relates to the field of aircraft mobile production lines, in particular to a buffering uniform-load two-dimensional wheel set and a rigidity configuration method thereof, and the buffering uniform-load two-dimensional wheel set comprises a fixed wheel carrier, a buffering suspension, a movable wheel carrier and a sealing plate; the buffer suspension comprises four buffer rod groups which are distributed in parallel at the same height, and the buffer rod groups are fixed at four corners of an internal space clamped by the top plate and the bottom plate and are distributed in a rectangular shape; the movable wheel carrier comprises a cavity and a moving assembly connected to the cavity, eight mounting lugs with round holes are arranged on the two sides of the outer face of the cavity, mounting holes of the moving assembly are formed in the upper side and the lower side of the interior of the cavity, and the movable wheel carrier is arranged on the buffer rod set of the buffer suspension in a sleeving mode through the round holes of the eight mounting lugs. The cavity penetrates through the rectangular-ambulatory-plane openings of the top plate and the bottom plate; the rigidity configuration method for the buffer uniform-load two-dimensional wheel set comprises a rigidity configuration method flow and a configuration method for main parameters of the spiral spring.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aircraft mobile production line, and particularly relates to a buffer uniform load two-dimensional wheel set and a rigidity configuration method thereof. BACKGROUND

[0002] In the field of aircraft mobile assembly production line, the rotation movement of large heavy-duty tooling and aircraft products is realized based on a wheel set. Since the stability requirement of aircraft assembly tooling is very high, it is usually required that the deformation thereof is not greater than 0.1 mm, and the long-distance movement of large assembly tooling is the main factor causing the deformation. In the process of rotation movement, the following objective factors exist, so that the movement of large assembly tooling is prone to cause deformation.

[0003] (1) High-precision deformation control requirement of large mobile assembly tooling on the production line: the moving length of aircraft assembly tooling on the mobile production line is more than hundreds of meters, even up to thousands of meters. Even if the flatness of the ground and the installation accuracy of the ground rail are well controlled, the height difference of the ground and the ground rail can only be controlled to be 10 mm at most, and is generally about 30 mm, under the length magnification effect. Due to the shape and position error of the ground and the ground rail on the production line, the wheel set needs to be provided with a buffer uniform load device, so that the large assembly tooling can suppress the impact and keep the force uniform during the impact process, so that the stress state of the large assembly tooling is kept stable, and then the deformation of the large assembly tooling is controlled.

[0004] (2) High-robustness stable control requirement of large mobile assembly tooling on the production line: most of the wing assembly tooling is a planar structure, that is, the length size is large, the height size is large, but the width size is small. From the perspective of force, the center of gravity of the wing assembly tooling is high, but the distance between the feet in the width direction is narrow. Due to the shape and position error of the ground and the ground rail, the disconnection and connection of the longitudinal and transverse cross rails on the production line and other factors, the impact and uneven force of the wing assembly tooling are easily caused during the movement process, and then the risk of side leaning of the wing assembly tooling during the movement and assembly process is caused.

[0005] In order to solve the problems of deformation and instability of large high-center-of-gravity assembly tooling on the mobile production line, a device and method for impact buffering and force stabilization of the mobile assembly tooling on the production line are needed. SUMMARY

[0006] The purpose of the application is to realize the high-precision deformation control and high-robustness stable control of large mobile assembly tooling on the aircraft production line, and a buffer uniform load two-dimensional wheel set and a buffer uniform load rigidity configuration method thereof are provided.

[0007] In a first aspect, the application provides a buffer uniform load two-dimensional wheel set, which comprises a fixed wheel frame, a buffer suspension, a movable wheel frame and a sealing plate. The fixed wheel frame comprises a vertical plate, a top plate with a H-shaped opening and a bottom plate with a H-shaped opening, and the four corners of the top plate and the bottom plate are respectively provided with coaxial stepped connecting holes; The buffer suspension comprises four buffer rod groups distributed in parallel at the same height, which are fixed at the four corners of the internal space between the top plate and the bottom plate and are distributed in a rectangular shape; The movable wheel frame comprises a cavity and a motion assembly connected to the cavity, the outer sides of the cavity are provided with eight mounting ear pieces with round holes, and the upper and lower sides of the inner part of the cavity are provided with mounting holes of the motion assembly; The movable wheel frame is sleeved on the buffer rod groups of the buffer suspension through the round holes of the eight mounting ear pieces, and the cavity passes through the H-shaped openings of the top plate and the bottom plate; the sealing plate is a thin-walled structure, which covers the outer surfaces of the top plate and the bottom plate of the fixed wheel frame and is fixed on the top plate and the bottom plate.

[0008] Preferably, the buffer rod group comprises one buffer rod, two connecting nuts, two pre-pressing nuts, two spiral springs and one indexing nut; The buffer rod is sequentially provided with symmetrical connecting screw rods, pre-pressing screw rods, spiral spring guide rods and indexing screw rods from both ends to the middle; The connecting nut, the pre-pressing nut, the spiral spring and the indexing nut respectively form a connecting threaded pair, a pre-pressing threaded pair, a buffer moving pair and an indexing threaded pair with the connecting screw rod, the pre-pressing screw rod, the spiral spring guide rod and the indexing screw rod.

[0009] Preferably, the sum of the free length of the spiral spring and the thickness of the pre-pressing nut is equal to the sum of the length of the pre-pressing screw rod and the length of the spiral spring guide rod.

[0010] Preferably, the outer diameter of the pre-pressing screw rod is equal to the outer diameter of the spiral spring guide rod.

[0011] Preferably, the motion assembly comprises an X-direction wheel group motion assembly and a Y-direction wheel group motion assembly; The X-direction wheel group motion assembly and the Y-direction wheel group motion assembly are orthogonally distributed in a T shape; the X-direction wheel group motion assembly and the Y-direction wheel group motion assembly each comprise a set of power assembly, a set of lifting pair, two sets of guide pair and a set of wheel pair; the power assembly comprises a reducer with mechanical self-locking function, a servo motor and an encoder; the lifting pair comprises a screw rod and a nut; the guide pair comprises a guide column and a sleeve, and the wheel pair comprises a wheel seat and two horizontally arranged wheels mounted on the wheel seat.

[0012] Preferably, the center lines of one set of lifting pairs and the center lines of two sets of guide pairs in the X-direction wheel assembly are in the same plane and parallel, and the center lines of the two sets of guide pairs are symmetrical about the center line of the lifting pairs; the power assembly and the wheel assembly are respectively connected to the beginning end of the lead screw and the end of the lead nut in the lifting pairs.

[0013] Preferably, the center lines of one set of lifting pairs and the center lines of two sets of guide pairs in the Y-axis wheel assembly are in the same plane and parallel, and the center lines of the two sets of guide pairs are symmetrical about the center line of the lifting pairs; the power assembly and the wheel assembly are respectively connected to the beginning end of the lead screw and the end of the lead nut in the lifting pairs.

[0014] Preferably, the wheel assembly extends and retracts into the cavity through the combined action of the lifting pair and the guide pair.

[0015] Secondly, this application also provides a method for configuring the stiffness of a two-dimensional wheel assembly under buffered and uniform load, the method comprising: Step (9-1) Let the desired load acting on the wheel assembly under ideal ground flatness be... ; Step (9-2) Assume the actual flatness of the ground is... u The actual load of the wheel assembly under the actual flatness of the ground is ; Step (9-3) Assume the actual load Relative to the expected load Maximum volatility p ; Step (9-4) Configure the parameters of the helical spring: spring mean diameter d Expected compression length of spring Spring free length l Spring preload length and spring stiffness k ; Step (9-5): Pre-install the movable wheel frame into the fixed wheel frame, so that the axis of the circular hole in the four mounting lugs is coaxial with the axis of the four connecting holes in the fixed wheel frame; Step (9-6) Pre-install the buffer rod assembly into the movable wheel frame and the fixed wheel frame. The pre-installation method includes the following sub-steps: (9-6-1) Insert the buffer rod into the connecting hole of the base plate and the round hole for mounting the lugs below the movable wheel frame in sequence from bottom to top; (9-6-2) The helical spring, preload nut and indexing nut shall be sequentially fitted onto the buffer rod only when the buffer rod has completely passed through the connecting hole of the base plate and the round hole of the mounting lug below the movable wheel frame; (9-6-3) When the buffer rod is completely through the round hole of the mounting ear above the movable wheel frame, the coil spring and the pre-pressing nut are sequentially sleeved on the buffer rod; (9-6-4) When the connecting screw rods at both ends of the buffer rod are respectively in the connecting holes of the bottom plate and the top plate, the connecting nuts at both ends are respectively screwed in; Step (9-7) 8 pre-pressing nuts of 4 buffer rod groups are sequentially rotated, so that 8 coil springs are pre-pressed to the spring pre-pressing length .

[0016] Preferably, step (9-4) comprises: Step (10-1) The value range of the spring diameter d : ; Wherein, is the outer diameter of the coil spring guide rod, is the diameter of the spring wire; Step (10-2) Taking the actual flatness of the ground u and the maximum fluctuation rate p as independent variables, and the spring expected compression length as the dependent variable, a function of the spring expected compression length with respect to the flatness and the maximum fluctuation rate is constructed : ; Step (10-3) Taking the expected load and the spring expected compression length as independent variables, and the spring stiffness k as the dependent variable, a function of the spring stiffness with respect to the expected load and the spring expected compression length is constructed : ; Step (10-4) In order to prevent the spring from being disengaged, the spring pre-pressing length is set in relation to the spring expected compression length : ; Step (10-5) In order to prevent the spring from touching the bottom, taking the spring expected compression length and the spring pre-pressing length as independent variables, and the spring free length l as the dependent variable, a function of the spring free length with respect to the spring expected compression length and the spring pre-pressing length is constructed : .

[0017] The present application has the following advantages and remarkable benefits: (1) For the special application scenario of small deformation and high stability of high gravity center moving tooling in the long-distance production line of the aircraft, a two-dimensional heavy load wheel set based on 8 groups of spring parallel buffer is designed, which balances the contradiction between motion buffer and small deformation, and also balances the problem of uneven stress and high stability. (2) Compared with the existing spring stiffness configuration which adopts the method of continuous test and trial and error, the present method finds out the internal mechanism and rule of spring stiffness configuration, and solves the motion buffer performance and uniform load performance through forward research and development.

[0018] (3) In the production line with a length of thousands of meters and unevenness of ground and ground rail of 30 mm, the performance of controlling the stress change to 10% and the deformation to 0.1 mm when the large high gravity center tooling is subjected to impact is realized. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic diagram of a long-distance production line large vertical tooling and lifting and moving stability control system provided by the embodiment of the present application; Figure 2 is an enlarged view of the tooling, wheel set, attitude sensor and position sensor provided by the embodiment of the present application; Figure 3 is a wheel set structure schematic diagram (without sealing plate) provided by the embodiment of the present application; Figure 4 is an explosion view of the wheel set structure provided by the embodiment of the present application; Figure 5 is an explosion view of the movable wheel frame provided by the embodiment of the present application; Figure 6 is a position size diagram of the wheel set, attitude sensor and position sensor on the tooling provided by the embodiment of the present application; Figure 7 is a schematic diagram of two long-distance production line large vertical toolings provided by the embodiment of the present application; Figure 8 is a structure schematic diagram of the movable wheel frame provided by the embodiment of the present application; Figure 9 is a schematic diagram of a single long-distance production line large vertical tooling provided by the embodiment of the present application; Numbering in the figure: 1 buffer uniform load two-dimensional wheel group, 2 fixed wheel frame, 3 buffer suspension, 4 movable wheel frame, 5 sealing plate, 6 vertical plate, 7 top plate, 8 bottom plate, 9 buffer rod group, 10 cavity, 11 movement assembly, 12 mounting ear, 13 mounting hole, 14 buffer rod, 15 connecting nut, 16 pre-pressing nut, 17 spiral spring, 18 indexing nut, 19 connecting screw, 20 pre-pressing screw, 21 spiral spring guide rod, 22 indexing screw, 23 X-direction wheel group movement assembly, 24 Y-direction wheel group movement assembly, 25 power assembly, 26 lifting pair, 27 guide pair, 28 wheel pair, 29 speed reducer, 30 servo motor, 31 encoder, 32 screw, 33 nut, 34 guide column, 35 sleeve, 36 wheel seat, 37 wheel, 38 tooling, 39 production line. DETAILED DESCRIPTION

[0020] Please refer to Figures 1-9 , the specific embodiment of a buffer uniform load two-dimensional wheel group provided in the present application is: As Figure 1 shown, 8 buffer uniform load two-dimensional wheel groups 1 are installed at the same height on a large high-center-of-gravity horizontal vertical tooling 38, driving the tooling 38 to move and assemble on a long-distance longitudinal and transverse rotary production line 39.

[0021] As Figure 2 and Figure 3 shown, the buffer uniform load two-dimensional wheel group 1 includes a fixed wheel frame 2, a buffer suspension 3, a movable wheel frame 4, and a sealing plate 5.

[0022] As Figure 4 shown, the fixed wheel frame 2 includes a vertical plate 6, a top plate 7 with a back-shaped opening, and a bottom plate 8 with a back-shaped opening, and the top plate 7 and the bottom plate 8 are connected with the vertical plate 6 using high-strength bevel welding process; the four corners of the top plate 7 and the four corners of the bottom plate 8 are respectively provided with coaxial stepped connection holes, the hole diameter of the inner hole in the stepped connection hole is in transition fit with the outer diameter of the connecting screw 19, and the hole diameter of the outer hole in the stepped connection hole is larger than the outer contour size of the connecting nut 15.

[0023] In the present embodiment, the vertical plate 6, the top plate 7, and the bottom plate 8 in the fixed wheel frame 2 are made of Q235 steel.

[0024] As Figure 2 and Figure 5 shown, the buffer suspension 3 includes 4 buffer rod groups 9 distributed in parallel at the same height, and the buffer rod groups 9 are fixed at the four corners of the internal space clamped by the top plate 7 and the bottom plate 8 and are distributed in a rectangular shape.

[0025] As Figure 2 , Figure 6 and Figure 7As shown, the movable wheel frame 4 includes a cavity 10 and a motion component 11 connected to the cavity 10. The outer sides of the cavity 10 are provided with eight mounting lugs 12 containing round holes. The upper and lower sides of the cavity 10 are provided with mounting holes 13 for the motion component 11. The movable wheel frame 4 is mounted on the buffer rod group 9 of the buffer suspension 3 through the round holes of the eight mounting lugs. The cavity 10 passes through the U-shaped opening of the top plate 7 and the bottom plate 8.

[0026] like Figure 2 As shown, the sealing plate 5 is a thin-walled structure that covers the outer surfaces of the top plate 7 and bottom plate 8 of the fixed wheel frame 2 and is fixed to the top plate 7 and bottom plate 8.

[0027] In this embodiment, the thickness of the sealing plate 5 is 3mm, and it is fixed to the outer surface of the top plate 7 and the bottom plate 8 with small bolts of 3mm diameter.

[0028] Further: like Figure 8 As shown, the buffer rod assembly 9 includes a buffer rod 14, two connecting nuts 15, two preload nuts 16, two helical springs 17, and an indexing nut 18. The buffer rod 14 is provided with a symmetrical connecting screw 19, a preload screw 20, a helical spring guide rod 21, and an indexing screw 22 from both ends to the middle. The connecting nuts 15, preload nuts 16, helical springs 17, and indexing nuts 18 respectively form a connecting thread pair, a preload thread pair, a buffer moving pair, and an indexing thread pair with the connecting screw 19, the preload screw 20, the helical spring guide rod 21, and the indexing screw 22.

[0029] like Figure 7 and Figure 9 As shown, the motion assembly 11 includes an X-axis wheel assembly 23 and a Y-axis wheel assembly 24; the X-axis wheel assembly 23 and the Y-axis wheel assembly 24 are orthogonally distributed in a T-shape; both the X-axis wheel assembly 23 and the Y-axis wheel assembly 24 include a power assembly 25, a lifting pair 26, two guide pairs 27, and a wheel assembly 28; the power assembly 25 includes a reducer 29 with mechanical self-locking function, a servo motor 30, and an encoder 31; the lifting pair 26 includes a lead screw 32 and a lead nut 33; the guide pair 27 includes a guide post 34 and a sleeve 35; the wheel assembly 28 includes a wheel seat 36 and two horizontally arranged wheels 37 mounted on the wheel seat 36.

[0030] like Figure 2 and Figure 7 As shown, the wheel assembly 28 extends out of and retracts into the cavity 10 through the combined action of the lifting assembly 26 and the guide assembly 27.

[0031] Furthermore: like Figure 8As shown, the sum of the free length of the helical spring 17 and the thickness of the preload nut 16 is equal to the sum of the length of the preload screw 20 and the length of the helical spring guide rod 21. The outer diameter of the preload screw 20 and the outer diameter of the helical spring guide rod 21 are equal. The connecting nut 15, the preload nut 16, and the indexing nut 18 are all anti-loosening self-locking nuts.

[0032] like Figure 9 As shown, in the X-direction wheel assembly 23, the centerline of one set of lifting joints 26 and the centerlines of two sets of guide joints 27 are in the same plane and parallel, and the centerlines of the two sets of guide joints 27 are symmetrical about the centerline of the lifting joint 26; the power assembly 25 and the wheel assembly 28 are respectively connected to the beginning end of the lead screw 32 and the end end of the lead nut 33 in the lifting joint 26. Based on the same configuration, in the Y-direction wheel assembly 24, the centerline of one set of lifting joints 26 and the centerlines of two sets of guide joints 27 are in the same plane and parallel, and the centerlines of the two sets of guide joints 27 are symmetrical about the centerline of the lifting joint 26; the power assembly 25 and the wheel assembly 28 are respectively connected to the beginning end of the lead screw 32 and the end end of the lead nut 33 in the lifting joint 26.

[0033] In other embodiments of this application, a method for configuring the stiffness of a buffer load using a two-dimensional buffer load-uniform wheel set 1 is also provided, which specifically includes the following steps: (1) Let the desired load acting on the buffer uniform load two-dimensional wheel assembly 1 under ideal ground flatness be . ; Setting the desired load is to determine the rated load of the wheelset under ideal operating conditions; (2) Let the actual flatness of the ground be... u Under the actual flatness of the ground, the actual load of the buffer uniform load two-dimensional wheel set 1 is: ; Set actual flatness u and actual load It is to describe the actual working conditions of the wheelset; (3) Assume the actual load Relative to the expected load Maximum volatility p ; Set maximum volatility p This is to constrain the ultimate load of the wheel set; (4) Main parameters for configuring helical spring 17: spring mean diameter d Expected compression length of spring Spring free length l Spring preload length and spring stiffness k ; These main parameters are key parameters for determining the stiffness configuration of the buffered uniform load two-dimensional wheel set. (5) Pre-assemble the movable wheel frame 4 into the fixed wheel frame 2, so that the axis of the circular hole in the four mounting tabs 12 is coaxial with the axis of the four connecting holes in the fixed wheel frame 2; (6) Pre-assemble the buffer rod set 9 into the movable wheel frame 4 and the fixed wheel frame 2, the pre-assembly method includes the following steps: (6-1) Insert the buffer rod 14 into the connecting hole of the bottom plate 2 and the circular hole of the mounting tab 12 below the movable wheel frame 4 in turn from bottom to top; (6-2) When and only when the buffer rod 14 completely passes through the connecting hole of the bottom plate 2 and the circular hole of the mounting tab 12 below the movable wheel frame 4, the coil spring 17, the pre-pressing nut 16 and the indexing nut 18 are successively sleeved onto the buffer rod 14; (6-3) When the buffer rod 14 completely passes through the circular hole of the mounting tab 12 above the movable wheel frame 4, the coil spring 17 and the pre-pressing nut 16 are successively sleeved onto the buffer rod 14; (6-4) When the connecting lead screws 19 at both ends of the buffer rod 14 are respectively in the connecting holes of the bottom plate 2 and the top plate 7, the connecting nuts 15 at both ends are respectively screwed in; (7) Rotate the eight pre-pressing nuts of the four buffer rod sets in turn, so that the eight coil springs are all pre-pressed to the spring pre-pressing length ; Further: The configuration method of the main parameters of the coil spring 17 specifically includes the following steps: (1) Configure the value range of the spring mean diameter d : ; Wherein is the outer diameter of the coil spring guide rod 21, is the diameter of the spring wire; (2) Take the actual flatness of the ground u and the maximum fluctuation rate p as independent variables, and the expected compression length of the spring as the dependent variable, to construct the function of the expected compression length of the spring about the flatness and the maximum fluctuation rate : ; (3) Take the expected load and the expected compression length of the spring as independent variables, and the spring stiffness k as the dependent variable, to construct the function of the spring stiffness about the expected load and the expected compression length of the spring : ; (4) To prevent the spring from coming off, set the spring pre-pressing length The ratio relationship of the expected compression length of the spring ; ; (5) In order to prevent the spring from bottoming out, the function of the free length of the spring with respect to the expected compression length of the spring and the pre-compression length of the spring is constructed with the expected compression length of the spring and the pre-compression length of the spring as independent variables and the free length of the spring as a dependent variable: l .

[0034] Compared with the prior art, the present application has the following advantages and remarkable benefits: (1) For the special application scenario of small deformation and high stability of the high gravity center moving tool in the long-distance production line of the aircraft, a two-dimensional heavy load wheel set based on 8 groups of parallel spring buffers is designed, which balances the contradiction between motion buffering and small deformation, and also balances the problem of uneven stress and high stability. (2) Compared with the existing spring stiffness configuration which adopts the method of continuous testing and trial and error, the present application finds the internal mechanism and rule of spring stiffness configuration, and solves the motion buffering performance and uniform load performance through forward research and development.

[0035] (3) In a production line with a length of more than 1,000 meters and a ground and rail unevenness of 30 mm, the performance of controlling the stress change to 10% and the deformation to 0.1 mm when the large high gravity center tool is subjected to impact is realized.

[0036] The market prospect of the present application is: (1) The present application has realized technical transformation in the field of aircraft longitudinal and transverse moving production line, and meets the buffering and uniform load of large high gravity center planar structure assembly tool with the characteristics of long distance, uneven ground and longitudinal and transverse reversing rotation.

[0037] (2) It can be extended to the control of high-performance buffering and uniform load on the moving production line of high-speed rail, rocket and large container.

[0038] (3) Compared with the precise guide rail type buffering mechanism, the present application greatly reduces the failure rate of lifting blockage, significantly shortens the development time, development cost and maintenance cost of the wheel set.​​​​

Claims

1. A buffer-load-uniform two-dimensional wheel set, characterized in that, The wheelset includes a fixed wheel frame, a buffer suspension, a movable wheel frame, and a sealing plate; The fixed wheel frame includes a vertical plate, a top plate with a U-shaped opening, and a bottom plate with a U-shaped opening. The four corners of the top plate and the four corners of the bottom plate are respectively provided with coaxial stepped connecting holes. The buffer suspension includes four buffer rod groups arranged in parallel at the same height. The buffer rod groups are fixed at the four corners of the internal space between the top plate and the bottom plate and are arranged in a rectangular shape. The movable wheel frame includes a cavity and a motion component connected to the cavity. The outer sides of the cavity are provided with eight mounting lugs containing round holes, and the upper and lower sides of the cavity are provided with mounting holes for the motion component. The movable wheel frame is fitted onto the buffer rod assembly of the buffer suspension through the eight round holes of the mounting lugs, and the cavity passes through the U-shaped opening of the top plate and the bottom plate; the sealing plate is a thin-walled structure that covers the outer surface of the top plate and the bottom plate of the fixed wheel frame and is fixed to the top plate and the bottom plate.

2. The wheelset according to claim 1, characterized in that, The buffer rod assembly includes a buffer rod, two connecting nuts, two preload nuts, two helical springs, and one indexing nut. The buffer rod is provided with symmetrical connecting screws, preload screws, helical spring guides and indexing screws from both ends toward the middle; The connecting nut, preload nut, helical spring, and indexing nut, together with the connecting screw, preload screw, helical spring guide rod, and indexing screw, respectively form a connecting threaded pair, a preloaded threaded pair, a buffer moving pair, and an indexing threaded pair.

3. The wheelset according to claim 2, characterized in that, The sum of the free length of the helical spring and the thickness of the preload nut is equal to the sum of the length of the preload screw and the length of the helical spring guide rod.

4. The wheelset according to claim 2, characterized in that, The outer diameter of the preload screw is equal to the outer diameter of the helical spring guide rod.

5. The wheelset according to claim 1, characterized in that, The motion components include an X-axis wheel assembly motion component and a Y-axis wheel assembly motion component; The X-axis wheel assembly and the Y-axis wheel assembly are orthogonally distributed in a T-shape. Each of the X-axis wheel assembly and the Y-axis wheel assembly includes a power assembly, a lifting pair, two guide pairs, and a wheel assembly. The power assembly includes a reducer with mechanical self-locking function, a servo motor, and an encoder. The lifting pair includes a lead screw and a lead nut. The guide pair includes a guide post and a sleeve. The wheel assembly includes a wheel seat and two horizontally arranged wheels mounted on the wheel seat.

6. The wheelset according to claim 5, characterized in that, The center lines of one set of lifting pairs and two sets of guide pairs in the X-axis wheel assembly are in the same plane and parallel, and the center lines of the two sets of guide pairs are symmetrical about the center line of the lifting pairs; the power assembly and the wheel assembly are respectively connected to the beginning end of the lead screw and the end of the lead nut in the lifting pairs.

7. The wheelset according to claim 5, characterized in that, The center lines of one set of lifting pairs and the center lines of two sets of guide pairs in the Y-axis wheel assembly are in the same plane and parallel, and the center lines of the two sets of guide pairs are symmetrical about the center line of the lifting pairs; the power assembly and the wheel assembly are respectively connected to the beginning end of the lead screw and the end of the lead nut in the lifting pairs.

8. The wheelset according to claim 1, characterized in that, The wheel assembly extends and retracts into the cavity through the combined action of the lifting pair and the guide pair.

9. A method for configuring the stiffness of a two-dimensional wheel set under buffered uniform load, characterized in that, The method includes: Step (9-1) Let the desired load acting on the wheel assembly under ideal ground flatness be... ; Step (9-2) Assume the actual flatness of the ground is... u The actual load of the wheel assembly under the actual flatness of the ground is ; Step (9-3) Assume the actual load Relative to the expected load Maximum volatility p ; Step (9-4) Configure the parameters of the helical spring: spring mean diameter d Expected compression length of spring Spring free length l Spring preload length and spring stiffness k ; Step (9-5): Pre-install the movable wheel frame into the fixed wheel frame, so that the axis of the circular hole in the four mounting lugs is coaxial with the axis of the four connecting holes in the fixed wheel frame; Step (9-6) Pre-install the buffer rod assembly into the movable wheel frame and the fixed wheel frame. The pre-installation method includes the following sub-steps: (9-6-1) Insert the buffer rod into the connecting hole of the base plate and the round hole for mounting the lugs below the movable wheel frame in sequence from bottom to top; (9-6-2) The helical spring, preload nut and indexing nut shall be sequentially fitted onto the buffer rod only when the buffer rod has completely passed through the connecting hole of the base plate and the round hole of the mounting lug below the movable wheel frame; (9-6-3) When the buffer rod has completely passed through the round hole of the mounting lug above the movable wheel frame, the helical spring and the preload nut are sequentially put into the buffer rod; (9-6-4) When the connecting screws at both ends of the buffer rod are respectively in the connecting holes of the bottom plate and the top plate, the connecting nuts at both ends are screwed in respectively; Step (9-7): Rotate the eight preload nuts of the four buffer rod assemblies in sequence to preload all eight helical springs to their preload length. .

10. The method according to claim 9, characterized in that, Step (9-4) includes: Step (10-1) Configure the spring mean diameter d The range of values ​​for: ； in, The outer diameter of the helical spring guide rod. The diameter of the spring steel wire; Step (10-2) Based on the actual flatness of the ground u and maximum volatility p As the independent variable, the desired compression length of the spring is... As the dependent variable, construct a function of the expected compression length of the spring with respect to flatness and maximum volatility. : ； Step (10-3) with desired load and the expected compression length of the spring As the independent variable, with the spring stiffness as... k As the dependent variable, construct a function of spring stiffness with respect to the desired load and the desired compression length of the spring. : ； Step (10-4): To prevent the spring from disengaging, set the spring preload length. Regarding the expected compression length of the spring The proportion relationship: ； Step (10-5): To prevent the spring from bottoming out, use the desired compression length of the spring. and spring preload length As the independent variable, the free length of the spring l As the dependent variable, construct a function of the spring's free length with respect to the spring's expected compression length and spring preload length. : 。

Images