Manned lunar vehicle brake and torque control method

Abstract

The invention discloses a manned lunar vehicle brake and a torque control method. A brake drum and a bottom plate are combined into a sealed shell. A plurality of friction plates are arranged on the surface of the inner circumference of the brake drum, and an assembling gap is formed between every two adjacent friction plates on the circumference. The two brake shoes are symmetrically distributed on the surface of the inner circumference of the brake drum, and a continuously-changing brake gap is formed between the working face of each brake shoe and the inner surface of the friction plate. The inner end of the rocker arm is sleeved on the cam shaft; and a pull wire for pulling the rocker arm is arranged at the end head of the outer end of the rocker arm. And a torque control assembly is mounted on the stay wire, so that the magnitude of braking force can be controlled. Three sealing effects are formed through the sealing ring, the sealing cover and the sealing ring cover plate, and the sealing performance of the brake is improved. Under the condition that functions are met, the weight is controlled within 1 kg, the weight of a common brake with the same friction radius is at least 2 kg or above, and the low-weight requirement of the brake is met.

Description

Technical Field

[0001] The present invention relates to the field of vehicle braking technology, and is suitable for wheels that have high requirements on weight, sealing and braking torque, and specifically relates to a manned lunar rover brake and torque control method. Technical Background

[0002] Manned lunar landing programs require the consideration of vehicles supporting astronauts' lunar activities, most notably lunar rovers. Lunar rover design requirements place stringent demands on brake torque control, weight, and operating environment. Conventional vehicle brakes are heavy, have poor sealing, and their braking mechanisms are largely exposed to the outside world. Furthermore, the control structure required to achieve braking function is complex, making them inadequate for lunar rover brake design. For example, the wheel brakes of certain vehicles are caliper brakes, often constructed of heavy steel. The brake discs and calipers are exposed to the atmosphere, making them difficult to seal. Hydraulic fluid is required to activate the calipers during braking, and reliable operation at extremely low temperatures is unreliable. Therefore, a brake design that is lightweight, well-sealed, and capable of controlling braking torque is crucial.

[0003] Patent application number CN118128842A discloses a braking device and design method for a lunar rover. This invention relates to a drum brake that achieves braking by driving a disc spring to contact a brake assembly with friction pads on a brake drum, and also provides a design method. This invention differs from the present invention in the following essential ways: 1. The purpose of this invention is fundamentally different: while the purpose of this invention is to stop the wheels of the lunar rover and achieve parking, the purpose of this invention is to control the braking torque during the movement of the lunar rover by adjusting the travel of the brake handle, thereby achieving forward braking of the lunar rover. 2. The braking structure of this invention differs from that of the present invention. The brake assembly, a semi-arc-shaped metal frame, generates braking force in this invention. This brake assembly is a semi-arc-shaped metal frame that is pried along the brake's radial direction by a crank, contacting and locking the friction pads. The brake shoe, a pair of L-shaped curved pads, is driven by a rocker arm to rotate axially and contact the friction pads to generate braking torque, reducing wheel speed or stopping the wheel. 3. This invention and the present invention have different considerations on torque control. In order to stop the wheel from rotating, this invention only needs to consider whether the applied torque is sufficient to lock the wheel from rotating. The present invention needs to consider applying torques of different sizes during the rotation of the wheel to achieve different rates of deceleration of the wheel.

[0004] In the invention with publication number CN101249853, a road-adaptive diamond-shaped lunar rover mobile system with two active swing arms in the middle is disclosed. The structure of the invention mentions an electromagnetic brake that comes with the motor, which is a non-mechanical brake, and its purpose is to control the swing of the vehicle body of the mobile system, which is essentially different from the structure, purpose and use of the present invention. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, such as heavy weight, poor sealing and difficulty in controlling torque, the present invention proposes a manned lunar rover brake and a method for controlling torque.

[0006] The manned lunar rover brake proposed in the present invention includes a brake drum, friction pads, a sealing cover, a base plate, a sealing ring cover, a camshaft, a rocker arm, two brake shoes, a guide tube, a cable holder, and a travel compensation spring. The brake drum and base plate combine to form a sealed cavity, forming the housing of the manned lunar rover brake. Multiple friction pads are arranged on the inner circumference of the brake drum, with assembly gaps between adjacent friction pads. Two brake shoes are located within the housing, symmetrically distributed on the inner circumference of the brake drum. A brake gap is defined between the working surface of each brake shoe and the inner surface of the friction pad. This brake gap is variable, with a 1 mm brake gap at the working end and a 0.6 mm brake gap at the rotating end, and the gaps at both ends vary continuously. The brake shoe is located on the side of the friction pad closest to the base plate. The working ends of the two brake shoes are connected by a spring. The positioning ends of the two brake shoes are respectively mounted on brake shoe rotating pins located on the base plate. The rocker arm is located on the outer circumferential surface of the housing, with the inner end of the rocker arm being sleeved onto the camshaft, and the end surface of the rocker arm connecting end being in contact with and fixed to the end surface of the base plate. A return torsion spring is mounted within a circular sleeve at the rocker arm connecting end, with a latch at one end of the return torsion spring engaging a slot in the end surface of the base plate, and a latch at the other end of the return torsion spring engaging a slot in the inner end surface of the rocker arm.

[0007] A pull line for pulling the rocker arm is arranged at the end of the outer end of the rocker arm. A torque control assembly is installed on the pull line.

[0008] The sealing cover is sleeved on the outer circumferential surface of the shell and is located at the connection position between the brake and the base plate, so that the inner circumferential surface of one end of the sealing cover is fixedly connected to the outer circumferential surface of the brake, and the other end of the sealing cover is located on the outer circumference of the sealing ring cover plate, and there is a filtering gap between the inner circumferential surface of the sealing cover and the outer circumferential surface of the sealing ring cover plate.

[0009] The base plate is positioned within the housing, with the brake shoe positioning surface at the inner end of the base plate aligned with the end surface of the brake shoe. The camshaft passes through the camshaft mounting seat on the base plate, with the working section of the camshaft positioned within the housing and between the working ends of the two brake shoes. The retaining grooves of the working section of the camshaft respectively engage with the outer surfaces of the two brake shoes. The centerline of the camshaft is parallel to the centerline of the housing.

[0010] A sealing ring is sleeved on the outer circumferential surface of the brake drum to seal the gap between the base plate and the brake drum. A sealing ring cover is sleeved on the sealing ring and fixed to the outer circumferential surface of the base plate.

[0011] The brake shoe is divided into a friction plate contact section and a base plate contact section. One end of the base plate contact section is a positioning end, containing a mounting hole for the brake shoe's rotation pin. The centerline of this mounting hole is parallel to the centerline of the housing. The other end of the base plate contact section is a square boss, forming the working end of the base plate contact section, with an axial height of 5 mm. A return spring mounting hole is located at the circular arc end of the friction plate contact section, positioned at the working end of the base plate contact section. During assembly, the two ends of the return spring are mounted on the return spring mounting holes of each brake shoe. A fixing hole for securing the brake shoe is located on the inner circumferential surface in the middle of the base plate contact section. The centerline of this fixing hole is parallel to the centerline of the housing. The brake shoe is hinged to the base plate via a pin.

[0012] The brake drum is a titanium alloy cylindrical rotating body, open at one end. The center of the end plate at the other end features a through hole for the axle. The inner circumference of this through hole is octagonal, ensuring proper wheel assembly. The inner diameter of the brake drum is the same as the outer diameter of the friction plate. Connecting holes for the axle drive components are located along the inner circumference of the brake drum. Slots for the axle drive components are located along the outer circumference of the brake drum. A positioning notch for the wheel is located on the outer circumference of one end plate. The end plate has a tapered surface to ensure proper wheel assembly.

[0013] The outer diameter of the base plate is the same as the maximum outer diameter of the sealing ring cover plate, and the inner surface is an inner hexagon, which is used to cooperate with the outer hexagonal boss positioned on the axle. The outer circumferential surface of the base plate is evenly distributed with multiple radially protruding bosses, and each boss has a connection hole for connecting to the sealing ring cover plate. The end face of each boss adjacent to the sealing ring cover plate is a stepped surface, forming a positioning slot for the sealing ring cover plate. A circular camshaft mounting hole is opened on the base plate, and the center line of the camshaft mounting hole is parallel to the center line of the base plate. Multiple torsion spring mounting holes are evenly distributed around the camshaft mounting hole, and the center line of the torsion spring mounting hole is parallel to the center line of the camshaft mounting hole. A through hole is provided on the base plate for mounting the brake shoe rotating pin shaft, and the center line of the through hole is parallel to the center line of the base plate. The limit pin shaft holes are symmetrically distributed on the base plate.

[0014] The camshaft is divided into a limiting section, a working section, a driving section and a connecting section according to its function; wherein: the limiting section is a rectangular plate, the length of which is greater than the distance between the working ends of the two brake shoes, so as to realize axial limitation of the working ends of the brake shoes; the working section is square, and its two side surfaces are respectively fitted with the surface of the working end of a brake shoe. When the camshaft rotates, the contact between the surface of the working section and the surface of the working end of the brake shoe gradually changes to the contact between the two diagonal corners of the working section and the surface of the working end of the brake shoe, thereby enlarging the distance between the working ends of the two brake shoes, and then making the friction plate contact section of the brake shoe contact the friction plate, generating a braking torque to brake the wheel; the driving section is installed in the camshaft mounting hole on the base plate, and the clearance between the two is matched; the surface of the connecting section at the end of the camshaft is an outer hexagon, which is fixedly connected to the camshaft mounting hole on the rocker arm.

[0015] The outer diameter of the sealing ring matches the inner diameter of the sealing ring cover, and the inner diameter matches the outer diameter of the brake drum. An annular groove is provided on the inner circumferential surface of the sealing ring to form a cavity together with the sealing cover 3 to accommodate external dust.

[0016] The rocker arm is rod-shaped and made of titanium alloy. One end has a circular sleeve with a hexagonal camshaft mounting hole in its center. A torsion spring mounting hole is located to one side of the camshaft mounting hole; the centerline of the camshaft mounting hole is parallel to the centerline of the torsion spring mounting hole. The other end of the rocker arm has a threaded hole extending along its length for mounting a rocker arm gasket. A radially projecting boss is located to one side of the through-hole, and the boss's surface has a wire guide groove.

[0017] The rocker arm washer is an L-shaped titanium alloy plate with a 100° angle between its flat plate and vertical plate. Screw holes are located on the horizontal plate of the rocker arm washer. During assembly, the horizontal plate is positioned on the top end face of the rocker arm and is coaxially assembled with the screw holes on the rocker arm end face. A through slot for receiving the cable is located on the top surface of the horizontal plate.

[0018] The guide tube is a thin-walled cylindrical structure with an end plate at one end, which has a central hole for the wire guide. The other end is open. The wire guide seat is a cylindrical block. An annular groove is machined into the end surface of one end of the wire guide seat. The inner surface of this groove is threaded for connection to the guide tube. A hole for the travel compensation spring is machined into the central boss of this annular groove. A radial groove is machined into the circumference of the other end of the wire guide seat. The inner cavity of this groove is sized to accommodate the installation requirements of the positioning block on the wire guide. A through-hole for the wire guide is formed in the end surface of the wire guide seat at one end of the groove. Two wire guides are made of stainless steel filaments: the first wire guide and the second wire guide. Each wire guide has a positioning block at one end. During assembly, the end of the first wire guide with the positioning block is inserted into the guide tube, and one end of the wire guide seat is threadedly connected to the other end of the guide tube. The positioning block 3 of the second wire guide is installed in the groove, and one end of the wire guide is connected to the inner end surface of the groove. The other end of the wire guide is passed through the wire guide hole in the end surface of the wire guide seat. The stroke compensation spring is located so that one end of the stroke compensation spring is connected to the first pull wire and the other end is connected to the central boss of the pull wire seat.

[0019] The present invention also proposes a method for controlling the braking torque of the manned lunar rover, the specific process of which is as follows:

[0020] Step 1: Determine the brake cable travel L' and the maximum torque M required:

[0021] The brake cable travel L' is determined by the working radius r and the maximum rotation angle δ1 of the brake handle. Specifically:

[0022] L'=rδ1

[0023] Through the lunar rover's vehicle weight m and lunar surface binding coefficient μ gd , wheel rolling radius R gd Determine the maximum torque M required for output. Specifically:

[0024]

[0025] Obtain the target value of the brake cable travel L' and the required maximum output torque M;

[0026] Step 2: Determine the coefficient of friction of the friction material:

[0027] The friction coefficient μ of the friction couple between the brake drum and the brake shoe is measured through experiments;

[0028] Step 3: Obtain the structural parameters of the brake:

[0029] The structural parameters of the brake include the force arm h of the opening force p on the fulcrum, the distance f from the brake shoe support point to the center of the brake base plate, the radius R of the brake drum, the brake shoe lining angle θ, the angle θ1 between the line connecting the brake shoe support point to the center of the brake base plate and the line connecting the lining end point to the center of the brake base plate, the rocker arm angle δ2, the force arm a of the opening force p on the camshaft and the rocker arm length A.

[0030] The structural parameters of the brake are obtained through overall design.

[0031] Step 4: Calculate the geometric parameters of the brake;

[0032] The geometric parameters of the brake include the friction angle γ, the diameter of the pressure center circle l0, the angle α between the maximum brake pressure line and the bisector of the brake shoe lining angle, the angle β between the line connecting the brake pressure center to the center of the brake base plate and the bisector of the brake shoe lining angle, and the angle λ between the equivalent total pressure direction on the brake shoe consistent with the rotation direction of the brake drum and its corresponding fulcrum force arm. t1 , the angle λ between the equivalent total pressure direction of the brake shoe opposite to the rotation direction of the brake drum and its force arm to the fulcrum t2 , the proportional coefficient ζ of the lever arm h relative to the radius R of the brake drum, the proportional coefficient k of the distance f relative to the radius R of the brake drum, and the proportional coefficient ρ of the pressure center circle diameter l0 relative to the radius R of the brake drum.

[0033] The friction angle γ is obtained by the formula:

[0034] γ=arctanμ

[0035] In Equation 3, μ is the friction coefficient of the friction couple between the brake drum and the brake shoe measured in step 2;

[0036] The pressure center circle diameter l0 is obtained by formula (4):

[0037]

[0038] In Equation 4, θ is the brake shoe lining wrap angle obtained in step 3, and R is the radius of the brake drum obtained in step 3.

[0039] The angle α between the maximum braking pressure line and the bisector of the brake shoe lining angle is obtained by the formula:

[0040]

[0041] In formula 5, θ1 is the angle between the line connecting the brake shoe support point to the center of the brake base plate obtained in step 3 and the line connecting the end point of the lining to the center of the brake base plate.

[0042] The angle β between the line connecting the brake pressure center to the center of the brake base plate and the bisector of the brake shoe lining angle is obtained by formula (6):

[0043]

[0044] By using formula 7, we can get the angle λ between the direction of the equivalent resultant pressure on the brake shoe, which is consistent with the rotation direction of the brake drum, and its force arm to the fulcrum. t1 .

[0045] λ t1 =γ+β-α (7)

[0046] By using formula 8, we can get the angle λ between the equivalent total pressure direction of the brake shoe opposite to the rotation direction of the brake drum and its force arm to the fulcrum. t2 .

[0047] λ t2 =γ-β+α (8)

[0048] The proportional coefficient ζ of the lever arm h relative to the radius R of the brake drum is obtained by formula 9:

[0049] ζ=h / R

[0050] In Equation 9, h is the moment arm of the opening force p obtained in step 3 relative to the fulcrum, and R is the radius of the brake drum obtained in step 3.

[0051] The proportional coefficient κ of the distance f relative to the radius R of the brake drum is obtained by formula 10:

[0052] k=f / R

[0053] In formula (10), f is the distance from the brake shoe support point to the center of the brake base plate obtained in step 3.

[0054] The proportional coefficient ρ of the pressure center circle diameter l0 to the brake drum radius R is obtained by formula 11:

[0055] ρ=l0 / R (11)

[0056] In formula 11, l0 is the pressure center circle diameter calculated by formula 4.

[0057] Step 5: Calculate the efficiency factor K of the brake shoe that rotates in the same direction as the brake drum t1 .

[0058] Calculate the efficiency factor K of the brake shoe that rotates in the same direction as the brake drum using formula 12. t1 :

[0059]

[0060] In formula 12, ζ is the proportional coefficient of the force arm h obtained in formula 9 to the radius R of the brake drum, κ is the proportional coefficient of the distance f obtained in formula 10 to the radius R of the brake drum, and λ ist1 is the angle between the equivalent resultant pressure direction on the brake shoe with the same rotation direction of the brake drum obtained by formula 7 and its fulcrum force arm, ρ is the proportional coefficient of the pressure center circle diameter l0 relative to the brake drum radius R obtained by formula 11, β is the angle between the line from the brake pressure center to the center of the brake base plate obtained by formula 6 and the bisector of the brake shoe lining angle, and γ is the friction angle obtained by formula 3.

[0061] Step 6: Calculate the efficiency factor K of the brake shoe that rotates in the opposite direction to the brake drum t2

[0062] Calculate the efficiency factor K of the brake shoe that rotates in the opposite direction to the brake drum using formula 13. t2 :

[0063]

[0064] In formula 13, λ t2 The equivalent total pressure direction of the brake shoe opposite to the rotation direction of the brake drum and the angle between the brake shoe and the fulcrum lever arm are obtained from Formula 8. The meanings of the other parameters are the same as those in Formula 12.

[0065] Step 7: Calculate the brake efficiency factor K t :

[0066] Calculate the brake efficiency factor K by the formula t :

[0067] K t =K t1 +K t2

[0068] Where K t is the efficiency factor of the brake, K t1 is the efficiency factor of the brake shoe with the same rotation direction as the brake drum obtained in step 5; K t2 is the efficiency factor of the brake shoe in the opposite direction of the brake drum rotation obtained in step 6.

[0069] Step 8: Calculate the brake opening force p:

[0070]

[0071] In Equation 15, M is the maximum torque required to be output determined in step 1, and K is t is the efficiency factor of the brake determined in step 7, and R is the radius of the brake drum obtained in step 3.

[0072] Step 9: Calculate the required brake input force P:

[0073]

[0074] In Equation 16, p is the required brake opening force obtained in step 8, a is the camshaft moment arm of the opening force p obtained in step 3, and A is the rocker arm length obtained in step 3.

[0075] Step 10: Calculate the spring constant k:

[0076]

[0077] In Equation 17, P is the brake input force obtained in step 9, L' is the brake cable stroke obtained in step 1, A is the rocker arm length obtained in step 3, and δ2 is the rocker arm angle obtained in step 3.

[0078] Step 11: Select the travel compensation spring:

[0079] A stroke compensation spring is selected according to the spring coefficient k, and both ends of the spring are connected to the above-mentioned adjustment spring seat 13 and the wire seat respectively.

[0080] Step 9: Control of brake output braking torque:

[0081] The brake output torque is controlled by controlling the stroke of the handle.

[0082] When the travel of the lunar rover's brake handle is 0~Aδ2, the brake has no torque output.

[0083] When the handle stroke is greater than Δδ2 and reaches L′, the brake outputs torque M.

[0084] At this point, the control of the braking torque of the manned lunar rover is completed.

[0085] Compared with traditional vehicle brakes, the present invention significantly reduces weight, seals the brake's friction pair in a cavity at the installation location to prevent the ingress of impurities, and controls the output of the braking torque by adjusting the cable travel. Compared with existing technologies, the present invention achieves the following beneficial effects:

[0086] 1. The braking mechanism of existing brakes lacks a seal from the external environment. To ensure the tightness of the housing formed between the brake drum and the base plate, keep the brake operating area clean, and prevent the seizure of rotating parts, the present invention incorporates a special-shaped sealing ring, a sealing cover, and a sealing ring cover plate at the mating point between the brake drum and the base plate. Compared to the circular cross-section of a conventional O-ring, the special-shaped sealing ring has a stepped rectangular cross-section, and a groove is defined along the perimeter of the mid-diameter end face of the small end of the special-shaped sealing ring. The special-shaped sealing ring, sealing cover, and sealing ring cover plate form three sealing effects: 1) The sealing cover and sealing ring cover plate provide the first sealing effect, preventing impurities larger than the gap between them from entering the sealing cover and sealing ring cover plate; 2) The groove of the special-shaped sealing ring and the sealing cover provide the second sealing effect, forming a cavity between them to accommodate small amounts of impurities that enter from the outside, preventing them from being retained in the sealing area between the special-shaped sealing ring, the brake drum, and the base plate. Impurities are then expelled from the cavity by the rotation of the brake drum; 3) The third sealing effect is formed at the junction of the special-shaped sealing ring, the brake drum, and the base plate, preventing dust from entering the housing formed between the brake drum and the base plate. The sealing structure formed by the special-shaped sealing ring, sealing cover, sealing ring cover plate, together with the brake drum and base plate, improves the sealing performance of the brake.

[0087] 2. In the prior art, brakes reduce weight by opening lightening holes. The present invention reduces weight while ensuring sealing, and replaces weight-reducing holes on parts with weight-reducing grooves, thin-walled structures, etc. In order to offset the weight increase brought by grooves and thin-walled structures compared to weight-reducing holes, the following creative work was carried out: 1) Titanium alloys and aluminum alloys with low density and high strength were selected as part materials instead of steel materials, reducing product weight while ensuring part strength and rigidity; 2) The brake drum, base plate and brake shoe structures were optimized, with the thinnest part of the thin-walled area being 0.5mm, and strength and rigidity simulation calculations were performed, with stress and deformation within the allowable range of the material and brake. 3) The types, quantities, and materials of brake parts have been verified to be able to control the weight within 1kg while meeting the functional requirements. The weight of a general brake with the same friction radius is at least 2kg, ensuring the low weight requirement of the brake.

[0088] 3. With existing purely mechanical brakes, once the travel clearance is eliminated, the handle that applies the braking force cannot be rotated further, and the braking force cannot be correlated with the handle travel, or a brake drive mechanism must be added before the brake. This invention adds a travel compensation spring to the cable and controls the braking force by adjusting the spring rate and handle travel. This allows the braking torque to be controlled by the handle travel, while also avoiding the added weight of the brake caused by the use of a complex brake drive mechanism.

[0089] Compared with existing lunar rover brake technology, the present invention is a new type of mechanical brake structure and, for the first time, proposes a method for controlling the brake torque, allowing the driver to manipulate the torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] Figure 1 This is a schematic diagram of the structure of the lunar rover brake; Figure 1 a is the axonometric view of the lunar rover brake. Figure 1 b is the main view of the lunar rover brake, Figure 1 c is the left view of the lunar rover brake.

[0091] Figure 2 yes Figure 1 b Sectional view along AA;

[0092] Figure 3 yes Figure 2 A partial enlarged view of Figure 3 a is Figure 2 The enlarged view of the middle part Ⅰ, Figure 3 b is Figure 2 The enlarged view of the middle II part, Figure 3 c is Figure 2 Enlarged view of part III.

[0093] Figure 4 yes Figure 2 Cross-sectional view along BB.

[0094] Figure 5 yes Figure 4 Enlarged view of the middle IV area.

[0095] Figure 6 It is a structural diagram of the friction plate.

[0096] Figure 7 It is a structural diagram of the sealing cover.

[0097] Figure 8 It is a structural diagram of the bottom plate: Figure 8 a is the axonometric view of the front side of the base plate. Figure 8 b is the axonometric view of the back of the base plate. Figure 8 c is the main view of the base plate, Figure 8 d is Figure 8 c Cross-sectional view along CC, Figure 8 e is the rear view of the base plate.

[0098] Figure 9 It is a structural diagram of the sealing ring cover.

[0099] Figure 10 It is a schematic diagram of the structure of the camshaft; Figure 10 a is the camshaft side view, Figure 10 b is the main view of the camshaft, Figure 10 c is Figure 10 b Cross-sectional view along DD, Figure 10 d is the rear view, Figure 10 e is a top view.

[0100] Figure 11 It is a structural diagram of the rocker arm; Figure 11 a is the axonometric view of the front of the rocker arm. Figure 11 b is the axonometric view of the back of the rocker arm. Figure 11 c is the main view of the rocker arm, Figure 11 d is Figure 11 c is the cross-section along EE, Figure 11 e is Figure 11 d’s F-direction view.

[0101] Figure 12 It is a schematic diagram of the structure of the brake shoe; Figure 12 a is an axonometric view, Figure 12 b is the front view.

[0102] Figure 13 It is a schematic diagram of the pin structure; Figure 13 a is the main view, Figure 13 b is Figure 13 Axonometric drawing of a.

[0103] Figure 14 It is a structural diagram of the rocker arm gasket; among them, Figure 14 a is an axonometric drawing, Figure 14 b is Figure 14 A top view of a, Figure 14 c is the front view.

[0104] Figure 15 This is the installation diagram of the stroke compensation spring; Figure 15 a is the main view, Figure 15 b is Figure 15 Bottom view of a.

[0105] Figure 16 It is a schematic diagram of the working principle of the brake; Figure 16 a is the front view, Figure 16 b is the rear view, Figure 16 c is an enlarged view of V in 16a.

[0106] Figure 17 This is a schematic diagram of the strength calculation results of the brake drum under the design load. The maximum stress is 17.4MPa, which meets the material strength requirements.

[0107] Figure 18 This is a schematic diagram of the stiffness calculation results of the brake drum under the design load. The maximum deformation is 0.0052mm, which meets the deformation requirements.

[0108] Figure 19 This is a schematic diagram of the strength calculation results of the brake shoe under the design load. The maximum stress is 379MPa, which meets the material strength requirements.

[0109] Figure 20 This is a schematic diagram of the stiffness calculation results of the brake shoe under the design load. The maximum deformation is 0.31mm, which meets the deformation requirements.

[0110] Figure 21 This is a schematic diagram of the strength calculation results of the base plate under the design load. The maximum stress is 68.4MPa, which meets the material strength requirements.

[0111] Figure 22 This is a schematic diagram of the stiffness calculation results of the base plate under the design load. The maximum deformation is 0.0038mm, which meets the deformation requirements.

[0112] In the figure: 1. Brake drum; 2. Friction plate; 3. Sealing cover; 4. Rivet; 5. Base plate; 6. Sealing ring cover; 7. Camshaft; 8. Sealing ring; 9. Rocker arm; 10. Brake shoe; 11. Pin; 12. Rocker arm gasket; 13. Guide tube; 14. Cable holder; 15. Stroke compensation spring; 16. Brake clearance; 17. Friction plate contact section; 18. Base plate contact section; 19. Slot; 20. Locating stop; 21. Return torsion spring; 22. First cable; 23. Second cable. DETAILED DESCRIPTION

[0113] This embodiment is a manned lunar rover brake, comprising a brake drum 1, friction pads 2, a sealing cover 3, a base plate 5, a sealing ring cover 6, a camshaft 7, a rocker arm 9, two brake shoes 10, a guide tube 13, a cable holder 14, and a travel compensation spring 15. The brake drum 1 and base plate 5 combine to form a sealed cavity, forming the housing of the manned lunar rover brake. Multiple friction pads are arranged on the inner circumference of the brake drum, with assembly gaps between adjacent friction pads. Two brake shoes 10 are located within the housing, symmetrically distributed on the inner circumference of the brake drum 1. A brake gap 16 is defined between the working surface of each brake shoe and the inner surface of the friction pad 2. This brake gap is variable, with a gap of 1 mm at the working end and a gap of 0.6 mm at the rotating end, and the brake gaps at both ends vary continuously. The brake shoes 10 are located on the side of the friction pad 2 closest to the base plate 5. The working ends of the two brake shoes are connected by a spring; their positioning ends are respectively mounted on brake shoe rotation pins located on the base plate. The end face of the rocker arm's connecting end is aligned with the end face of the base plate 5 and secured with screws. A return torsion spring 21 is mounted within the circular sleeve at the rocker arm's connecting end. The pin at one end of the return torsion spring engages with a slot in the end face of the base plate, while the pin at the other end engages with a slot in the inner end face of the rocker arm.

[0114] The base plate 5 is positioned within the housing, with the brake shoe positioning surface at the inner end of the base plate 5 aligned with the end surface of the brake shoe. The camshaft 7 passes through the camshaft mounting seat on the base plate 5, with the working section of the camshaft positioned within the housing and between the working ends of the two brake shoes. The retaining grooves of the working section of the camshaft respectively align with the outer surfaces of the two brake shoes. The centerline of the camshaft is parallel to the centerline of the housing.

[0115] A rocker arm 9 is arranged on the outer circumference of the housing, and the inner end of the rocker arm is sleeved on the camshaft. A pull line for pulling the rocker arm is arranged at the end of the outer end of the rocker arm. A torque control assembly is installed on the pull line.

[0116] A sealing ring is mounted on the outer circumferential surface of the brake drum 1 to seal the gap between the base plate 5 and the brake drum. A sealing ring cover plate 6 is mounted on the sealing ring and fixed to the outer circumferential surface of the base plate 5.

[0117] The sealing cover 3 is sleeved on the outer circumferential surface of the shell and is located at the connection part between the brake and the base plate, so that the inner circumferential surface of one end of the sealing cover is fixedly connected to the outer circumferential surface of the brake, and the other end of the sealing cover is located on the outer circumference of the sealing ring cover plate, and there is a filtering gap between the inner circumferential surface of the sealing cover 3 and the outer circumferential surface of the sealing ring cover plate.

[0118] The brake shoe 10 is a thin-walled, semicircular titanium alloy part with an outer diameter of 138 mm. Functionally, it is divided into a friction pad contact section 17 and a base plate contact section 18. One end of the base plate contact section serves as a positioning end, housing a mounting hole for the brake shoe's rotation pin. The centerline of this mounting hole is parallel to the centerline of the housing. The other end of the base plate contact section is a square boss, forming the working end of the base plate contact section 18. The axial height of this working end is 5 mm. A return spring mounting hole is located at the arcuate end of the friction pad contact section, positioned at the working end of the base plate contact section. During assembly, the two ends of the return spring are mounted on the return spring mounting holes of each brake shoe. A fixing hole for securing the brake shoe is located on the inner circumferential surface of the base plate contact section 18, with its centerline parallel to the centerline of the housing. The brake shoe is hinged to the base plate 5 via a pin.

[0119] The friction plates are multiple, curved plates made of powdered alloy and 4 mm thick. Their outer surfaces mate with the inner surface of the brake drum. Each friction plate has mounting holes through which it is riveted to the brake drum. In this embodiment, there are six friction plates.

[0120] The brake drum 1 is a titanium alloy cylindrical rotating body, open at one end. The center of the end plate at the other end features a through hole for the axle. The inner circumference of this through hole is octagonal, ensuring proper wheel assembly. The inner diameter of the brake drum is the same as the outer diameter of the friction plate. Connecting holes for the axle drive components are located along its inner circumference. Slots 19 for the axle drive components are located along its outer circumference. A wheel-aligned stop 20 is located on the outer circumference of one end plate. The end plate has a tapered surface to ensure proper wheel assembly.

[0121] The sealing cover 3 is a stainless steel ring with a Z-shaped cross-section. The inner diameter of the larger outer diameter end of the sealing cover is slightly larger than the outer diameter of the sealing ring cover plate, while the inner diameter of the smaller outer diameter end is the same as the outer diameter of the brake drum. Connection holes for the brake hub are distributed around the circumference of the smaller outer diameter end.

[0122] The base plate 5 is a circular ring made of titanium alloy. Its outer diameter is the same as the maximum outer diameter of the sealing ring cover 6. Its inner surface is an internal hexagonal shape, designed to mate with the external hexagonal bosses on the axle. The base plate's outer circumference is uniformly distributed with multiple radially projecting bosses, each with a connection hole for attaching to the sealing ring cover. The end faces of each boss adjacent to the sealing ring cover are stepped, forming a positioning slot for the sealing ring cover. A circular camshaft mounting hole is defined in the base plate 5, with its centerline parallel to the centerline of the base plate. Multiple torsion spring mounting holes are distributed around the camshaft mounting hole, with their centerlines parallel to the centerline of the camshaft mounting hole. A through-hole for mounting the brake shoe rotation pin is also located in the base plate 5, with its centerline parallel to the centerline of the base plate. Limit pin holes are symmetrically distributed on the base plate.

[0123] The camshaft 7 is made of titanium alloy and is divided into a limiting section, a working section, a driving section and a connecting section according to its function; wherein: the limiting section is a rectangular plate, the length of which is greater than the distance between the working ends of the two brake shoes, so as to achieve axial limitation of the working end of the brake shoe; the working section is square, and its two side surfaces are respectively fitted with the surface of the working end of a brake shoe. When the camshaft rotates, the contact between the surface of the working section and the surface of the working end of the brake shoe gradually changes to the contact between the two diagonal corners of the working section and the surface of the working end of the brake shoe, thereby increasing the distance between the working ends of the two brake shoes, and then making the friction plate contact section of the brake shoe contact the friction plate, generating a braking torque to brake the wheel; the driving section is installed in the camshaft mounting hole on the base plate, and the clearance between the two is matched; the surface of the connecting section at the end of the camshaft is an outer hexagon, which is fixedly connected to the camshaft mounting hole on the rocker arm.

[0124] The rocker arm 9 is rod-shaped and made of titanium alloy. One end has a circular sleeve with a hexagonal camshaft mounting hole in its center. A torsion spring mounting hole is located to one side of the camshaft mounting hole; the centerline of the camshaft mounting hole is parallel to the centerline of the torsion spring mounting hole. The other end of the rocker arm has a threaded hole extending along its length for mounting a rocker arm gasket 12. A radially projecting boss is located to one side of the through-hole, with a wire guide groove on its surface.

[0125] The rocker arm spacer 12 is an L-shaped titanium alloy plate, with the angle between the horizontal and vertical plates forming the L-shape being 100°. A screw hole is provided on the horizontal plate of the rocker arm spacer. During assembly, the horizontal plate is positioned on the top end face of the rocker arm and is coaxially assembled with the screw hole in the rocker arm end face. A through slot for receiving the cable is provided on the top surface of the horizontal plate.

[0126] The torsion spring is a conical spiral structure with a bayonet at each end. The height of the torsion spring is equal to the distance from the end surface to the bottom surface of the circular sleeve at the rocker arm connection end.

[0127] The guide tube 13 is in the shape of a thin-walled cylinder, with an end plate at one end, and a wire drawing hole in the center of the end plate; the other end is open. The wire drawing seat 14 is in the shape of a cylindrical block. An annular groove is processed on the end face of one end of the wire drawing seat, and the inner surface of the groove is a threaded surface for connecting the guide tube; a hanging hole for the stroke compensation spring 15 is processed on the central boss of the annular groove. A radial groove is processed on the circumference of the other end of the wire drawing seat, and the size of the inner cavity of the groove must meet the installation requirements of the positioning block on the wire drawing 21. A through-hole for wire drawing is provided on the end face of one end of the groove of the wire drawing seat. There are two wires made of stainless steel filaments, namely the first wire drawing and the second wire drawing. There is a positioning block at one end of each wire drawing. During assembly, one end of the first cable with the positioning block is installed into the guide tube 13, and one end of the cable holder 14 is threadedly connected to the other end of the guide tube. The positioning block 3 of the second cable is installed in the groove, and one end of the cable is connected to the inner end surface of the groove, and the other end of the cable is passed through the cable hole on the end surface of the cable holder. The travel compensation spring 15 is located, with one end connected to the first cable and the other end connected to the central boss of the cable holder.

[0128] The sealing ring 8 is a rubber ring, whose outer diameter matches the inner diameter of the sealing ring cover 6, and whose inner diameter matches the outer diameter of the brake drum 1. There is an annular groove on the inner circumference of the sealing ring, which is used to form a cavity with the sealing cover 3 to accommodate external dust.

[0129] There is an annular groove at the middle diameter of the sealing ring, which is used to form a cavity together with the sealing cover 3 to accommodate external dust.

[0130] In this embodiment, when working, the brake drum 1 and the base plate 5 are connected to the wheel and the axle respectively through the interface screw holes thereon, and the rocker arm 9 and the rocker arm spacer 12 clamp the cable. When the wheel moves and the brake operation is performed, the tension is input from the cable, such as Figure 16 The rocker arm 9 is pulled to rotate around the central axis of the camshaft 7. When it rotates to an angle δ2, the brake shoe 10 is stretched open by the camshaft 7, contacts the friction plate 2 on the rotating brake drum 1 and generates friction; when the pulling force continues to increase, the wire pulls the stroke compensation spring 15 to cause deformation. At this time, the rocker arm 9 no longer rotates, but the output braking torque increases with the increase in the deformation of the stroke compensation spring 15, thereby realizing the control of the braking torque through the wire stroke.

[0131] The present invention also proposes a method for controlling the braking torque of the manned lunar rover, the specific process of which is as follows:

[0132] Step 1: Determine the brake cable travel L' and the maximum torque M required:

[0133] The brake cable travel L' is determined by the working radius r and the maximum rotation angle δ1 of the brake handle. Specifically:

[0134] L'=rδ1

[0135] Through the lunar rover's vehicle weight m and lunar surface binding coefficient μ gd , wheel rolling radius R gd Determine the maximum torque M required for output. Specifically:

[0136]

[0137] Obtain the target value of the brake cable travel L' and the required maximum output torque M;

[0138] Step 2: Determine the coefficient of friction of the friction material:

[0139] The friction coefficient μ of the friction couple between the brake drum and the brake shoe is measured through experiments;

[0140] Step 3: Obtain the structural parameters of the brake:

[0141] The structural parameters of the brake include the force arm h of the opening force p on the fulcrum, the distance f from the brake shoe support point to the center of the brake base plate, the radius R of the brake drum, the brake shoe lining angle θ, the angle θ1 between the line connecting the brake shoe support point to the center of the brake base plate and the line connecting the lining end point to the center of the brake base plate, the rocker arm angle δ2, the force arm a of the opening force p on the camshaft and the rocker arm length A.

[0142] The structural parameters of the brake are obtained through overall design.

[0143] Step 4: Calculate the geometric parameters of the brake;

[0144] The geometric parameters of the brake include the friction angle γ, the diameter of the pressure center circle l0, the angle α between the maximum brake pressure line and the bisector of the brake shoe lining angle, the angle β between the line connecting the brake pressure center to the center of the brake base plate and the bisector of the brake shoe lining angle, and the angle λ between the equivalent total pressure direction on the brake shoe consistent with the rotation direction of the brake drum and its corresponding fulcrum force arm. t1 , the angle λ between the equivalent total pressure direction of the brake shoe opposite to the rotation direction of the brake drum and its force arm to the fulcrum t2 , the proportional coefficient ζ of the lever arm h relative to the radius R of the brake drum, the proportional coefficient k of the distance f relative to the radius R of the brake drum, and the proportional coefficient ρ of the pressure center circle diameter l0 relative to the radius R of the brake drum.

[0145] The friction angle γ is obtained by the formula:

[0146] γ=arctanμ

[0147] In Equation 3, μ is the friction coefficient of the friction couple between the brake drum and the brake shoe measured in step 2;

[0148] The pressure center circle diameter l0 is obtained by formula (4):

[0149]

[0150] In Equation 4, θ is the brake shoe lining wrap angle obtained in step 3, and R is the radius of the brake drum obtained in step 3.

[0151] The angle α between the maximum braking pressure line and the bisector of the brake shoe lining angle is obtained by the formula:

[0152]

[0153] In formula 5, θ1 is the angle between the line connecting the brake shoe support point to the center of the brake base plate obtained in step 3 and the line connecting the end point of the lining to the center of the brake base plate.

[0154] The angle β between the line connecting the brake pressure center to the center of the brake base plate and the bisector of the brake shoe lining angle is obtained by the formula:

[0155]

[0156] By using formula 7, we can get the angle λ between the direction of the equivalent resultant pressure on the brake shoe, which is consistent with the rotation direction of the brake drum, and its force arm to the fulcrum. t1 .

[0157] λ t1 =γ+β-α (7)

[0158] By using formula 8, we can get the angle λ between the equivalent total pressure direction of the brake shoe opposite to the rotation direction of the brake drum and its force arm to the fulcrum. t2 .

[0159] λ t2 =γ-β+α (8)

[0160] The proportional coefficient ζ of the lever arm h relative to the radius R of the brake drum is obtained by formula 9:

[0161] ζ=h / R

[0162] In Equation 9, h is the moment arm of the opening force p obtained in step 3 relative to the fulcrum, and R is the radius of the brake drum obtained in step 3.

[0163] The proportional coefficient κ of the distance f relative to the radius R of the brake drum is obtained by formula 10:

[0164] κ=f / R

[0165] In formula (10), f is the distance from the brake shoe support point to the center of the brake base plate obtained in step 3.

[0166] The proportional coefficient ρ of the pressure center circle diameter l0 to the brake drum radius R is obtained by formula 11:

[0167] ρ=l0 / R (11)

[0168] In formula 11, l0 is the pressure center circle diameter calculated by formula 4.

[0169] Step 5: Calculate the efficiency factor K of the brake shoe that rotates in the same direction as the brake drum t1 .

[0170] Calculate the efficiency factor K of the brake shoe that rotates in the same direction as the brake drum using formula 12. t1 :

[0171]

[0172] In formula 12, ζ is the proportional coefficient of the force arm h obtained in formula 9 to the radius R of the brake drum, κ is the proportional coefficient of the distance f obtained in formula 10 to the radius R of the brake drum, and λ is t1 is the angle between the equivalent resultant pressure direction on the brake shoe with the same rotation direction of the brake drum obtained by formula 7 and its fulcrum force arm, ρ is the proportional coefficient of the pressure center circle diameter l0 relative to the brake drum radius R obtained by formula 11, β is the angle between the line from the brake pressure center to the center of the brake base plate obtained by formula 6 and the bisector of the brake shoe lining angle, and γ is the friction angle obtained by formula 3.

[0173] Step 6: Calculate the efficiency factor K of the brake shoe that rotates in the opposite direction to the brake drum t2

[0174] Calculate the efficiency factor K of the brake shoe that rotates in the opposite direction to the brake drum using formula 13. t2 :

[0175]

[0176] In formula 13, λ t2 The equivalent total pressure direction of the brake shoe opposite to the rotation direction of the brake drum and the angle between the brake shoe and the fulcrum lever arm are obtained from Formula 8. The meanings of the other parameters are the same as those in Formula 12.

[0177] Step 7: Calculate the brake efficiency factor K t :

[0178] Calculate the brake efficiency factor K by the formula t :

[0179] K t =K t1 +K t2

[0180] Where K t is the efficiency factor of the brake, K t1 K is the efficiency factor of the brake shoe with the same rotation direction as the brake drum obtained in step 5; t2 is the efficiency factor of the brake shoe in the opposite direction of the brake drum rotation obtained in step 6.

[0181] Step 8: Calculate the brake opening force p:

[0182]

[0183] In Equation 15, M is the maximum torque required to be output determined in step 1, and K is t is the efficiency factor of the brake determined in step 7, and R is the radius of the brake drum obtained in step 3.

[0184] Step 9: Calculate the required brake input force P:

[0185]

[0186] In Equation 16, p is the required brake opening force obtained in step 8, a is the camshaft moment arm of the opening force p obtained in step 3, and A is the rocker arm length obtained in step 3.

[0187] Step 10: Calculate the spring constant k:

[0188]

[0189] In Equation 17, P is the brake input force obtained in step 9, L' is the brake cable stroke obtained in step 1, A is the rocker arm length obtained in step 3, and δ2 is the rocker arm angle obtained in step 3.

[0190] Step 11: Select the travel compensation spring:

[0191] A stroke compensation spring is selected according to the spring coefficient k, and both ends of the spring are connected to the above-mentioned adjustment spring seat 13 and the wire seat respectively.

[0192] Step 9: Control of brake output braking torque:

[0193] The brake output torque is controlled by controlling the stroke of the handle.

[0194] When the travel of the lunar rover's brake handle is 0~Aδ2, the brake has no torque output.

[0195] When the handle stroke > Aδ2 and reaches L', the brake outputs torque M.

[0196] At this point, the control of the braking torque of the manned lunar rover is completed.

Claims

1. A manned lunar rover brake, characterized in that: The invention comprises a brake drum (1), a friction plate (2), a sealing cover (3), a bottom plate (5), a sealing ring cover plate (6), a camshaft (7), a rocker arm (9), two brake shoes (10), a guide tube (13), a cable holder (14) and a stroke compensation spring (15); wherein: the brake drum (1) and the bottom plate (5) are combined into a sealed cavity to form the housing of the manned lunar rover brake; a plurality of friction plates are arranged on the inner circumferential surface of the brake drum, and there is an assembly gap between each adjacent friction plate on the circumference; the two brake shoes are located in the In the housing, there is a brake gap (16) symmetrically distributed on the inner circumferential surface of the brake drum, and between the working surface of each brake shoe and the inner surface of the friction plate (2); the brake gap is a variable gap, wherein the brake gap at the working end is 1 mm, and the brake gap at the rotating end is 0.6 mm, and the brake gaps at both ends are continuously changed; the brake shoe is located on the side of the friction plate close to the bottom plate; the working ends of the two brake shoes are connected by a spring; the positioning ends of the two brake shoes are respectively mounted on the brake shoe rotating pin located on the bottom plate; The rocker arm (9) is located on the outer circumferential surface of the housing, and the connecting end of the rocker arm is sleeved on the camshaft; a return torsion spring (21) is installed in the circular sleeve of the connecting end of the rocker arm, and the bayonet at one end of the return torsion spring is embedded in the slot on the end surface of the base plate, and the bayonet at the other end of the return torsion spring is embedded in the slot on the inner end surface of the rocker arm; a pull wire for pulling the rocker arm is provided at the end of the outer end of the rocker arm; a torque control component is installed on the pull wire; The sealing cover (3) is sleeved on the outer circumferential surface of the housing and is located at the connection portion between the brake and the base plate, so that the inner circumferential surface of one end of the sealing cover is fixedly connected to the outer circumferential surface of the brake, and the other end of the sealing cover is located on the outer circumference of the sealing ring cover plate, and a filtering gap is formed between the inner circumferential surface of the sealing cover and the outer circumferential surface of the sealing ring cover plate; The base plate (5) is located in the housing, and the brake shoe positioning surface at the inner end of the base plate is fitted with the end surface of the brake shoe; the camshaft (7) passes through the camshaft mounting seat on the base plate, so that the working section of the camshaft is located in the housing and between the working ends of the two brake shoes; the card slots of the working section of the camshaft are respectively fitted with the outer surfaces of the two brake shoes; the center line of the camshaft is parallel to the center line of the housing; A sealing ring is sleeved on the outer circumferential surface of the brake drum (1), and the gap between the base plate (5) and the brake drum is sealed by the sealing ring; a sealing ring cover plate (6) is sleeved on the sealing ring, and the sealing ring cover plate is fixed to the outer circumferential surface of the base plate (5).

2. A manned lunar rover brake as claimed in claim 1, characterized in that: The brake shoe (10) is divided into a friction plate contact section (17) and a base plate contact section (18); one end of the base plate contact section is a positioning end, and a mounting hole for a brake shoe rotation pin is provided at the positioning end, and the center line of the mounting hole is parallel to the center line of the housing; the other end of the base plate contact section is a square boss, forming a working end of the base plate contact section, and the axial height of the working end is 5 mm; a return spring hanging hole is provided at the arc end of the friction plate contact section, and the return spring hanging hole is located at the working end of the base plate contact section; during assembly, the two ends of the return spring are respectively hung on the return spring hanging holes of each brake shoe; a fixing hole for fixing the brake shoe is provided on the inner circumferential surface in the middle of the circumference of the base plate contact section, and the center line of the fixing hole is parallel to the center line of the housing; the brake shoe is hinged to the base plate (5) through a pin.

3. The manned lunar rover brake according to claim 1, characterized in that: The brake drum (1) is a titanium alloy cylindrical rotating body, one end of which is open, and the center of the end plate at the other end has a through hole that matches the axle, and the inner circumferential surface of the through hole is octagonal to meet the requirements of assembly with the wheel; the inner diameter of the brake drum is the same as the outer diameter of the friction plate; the inner circumferential surface of the brake drum is distributed with connecting holes that match the driving parts on the axle; the outer circumferential surface of the brake drum is distributed with slots (19) that match the driving parts on the axle; the outer circumferential surface of one end of the brake drum end plate is provided with a positioning stop (20) that matches the wheel; the end plate is conical to meet the requirements of assembly with the wheel.

4. The manned lunar rover brake according to claim 1, wherein: The outer diameter of the base plate (5) is the same as the maximum outer diameter of the sealing ring cover plate (6), and the inner surface is an inner hexagon, which is used to cooperate with the outer hexagonal boss positioned on the axle; the outer circumferential surface of the base plate is evenly distributed with a plurality of radially protruding bosses, and each boss has a connecting hole for connecting the sealing ring cover plate; the end surface of each boss adjacent to the sealing ring cover plate is a stepped surface, forming a positioning slot for the sealing ring cover plate; a circular camshaft mounting hole is opened on the base plate, and the center line of the camshaft mounting hole is parallel to the center line of the base plate; a plurality of torsion spring mounting holes are evenly distributed around the camshaft mounting hole, and the center line of the torsion spring mounting hole is parallel to the center line of the camshaft mounting hole; a through hole for mounting the brake shoe rotating pin shaft is provided on the base plate, and the center line of the through hole is parallel to the center line of the base plate; and the limiting pin shaft holes are symmetrically distributed on the base plate.

5. The manned lunar rover brake according to claim 1, characterized in that: The camshaft (7) is divided into a limiting section, a working section, a driving section and a connecting section according to its function; wherein: the limiting section is a rectangular plate, the length of which is greater than the distance between the working ends of the two brake shoes, so as to realize the axial limiting of the working ends of the brake shoes; the working section is square, and its two side surfaces are respectively fitted with the surface of the working end of a brake shoe. When the camshaft rotates, the contact between the working section surface and the working end surface of the brake shoe gradually changes to the contact between the two diagonal sections of the working section and the working end surface of the brake shoe, thereby widening the distance between the working ends of the two brake shoes, and then making the friction plate contact section of the brake shoe contact the friction plate, generating a braking torque, and braking the wheel; the driving section is installed in the camshaft mounting hole on the base plate, and the clearance between the two is matched; the surface of the connecting section at the end of the camshaft is an outer hexagon, and is fixedly connected to the camshaft mounting hole on the rocker arm.

6. The manned lunar rover brake according to claim 1, characterized in that: The rocker arm gasket (12) is an L-shaped thin plate of titanium alloy, and the angle between the horizontal plate and the vertical plate forming the L-shape is 100 degrees; a screw hole is provided on the horizontal plate of the rocker arm gasket, and during assembly, the horizontal plate is positioned on the top end face of the rocker arm and is coaxially assembled with the screw hole on the rocker arm end face through the screw hole; a through groove for accommodating a pull wire is provided on the upper surface of the horizontal plate.

7. The manned lunar rover brake according to claim 1, characterized in that: The outer diameter of the sealing ring (8) matches the inner diameter of the sealing ring cover (6), and the inner diameter matches the outer diameter of the brake drum (1); an annular groove is provided on the inner circumferential surface of the sealing ring, which is used to form a cavity together with the sealing cover 3 to accommodate external dust.

8. The manned lunar rover brake according to claim 1, characterized in that: The guide tube (13) is a thin-walled cylindrical shape, with an end plate at one end, and a wire drawing hole at the center of the end plate; the other end is open; the wire drawing seat (14) is a cylindrical block; an annular groove is machined on the end face of one end of the wire drawing seat, and the inner surface of the groove is a threaded surface for connecting the guide tube; a hanging hole for a stroke compensation spring (15) is machined on the central boss of the annular groove; a radial groove is machined on the circumference of the other end of the wire drawing seat, and the size of the inner cavity of the groove must meet the installation requirements of the positioning block on the wire drawing (21); the wire drawing seat has a through wire drawing hole on the end face of one end of the groove Through hole; there are two pull wires made of stainless steel filaments, namely the first pull wire and the second pull wire; one end of each pull wire has a positioning block; during assembly, one end of the first pull wire with the positioning block is installed in the guide tube (13), and one end of the pull wire seat is threadedly connected to the other end of the guide tube; the positioning block 3 of the second pull wire is installed in the groove, and one end of the pull wire is connected to the inner end face of the groove, and the other end of the pull wire is passed through the pull wire through hole of the end face of the pull wire seat; the stroke compensation spring (15) is located, and one end of the stroke compensation spring is connected to the first pull wire, and the other end is connected to the center boss of the pull wire seat.

9. A method for controlling brake torque of a manned lunar rover according to claim 1, characterized in that: The present invention also proposes a method for controlling the braking torque, the specific process of which is: Step 1: Determine the brake cable travel L' and the maximum torque M required: The brake cable travel L' is determined by the working radius r and the maximum rotation angle δ1 of the brake handle; specifically: L′=rδ1 (1) Through the lunar rover's vehicle weight m and lunar surface binding coefficient μ gd , wheel rolling radius R gd Determine the maximum torque M required for output; Specifically: Obtain the target value of the brake cable travel L' and the required maximum output torque M; Step 2: Determine the friction coefficient of the friction material: The friction coefficient μ of the friction couple between the brake drum and the brake shoe is measured through experiments; Step 3: Get the structural parameters of the brake: The structural parameters of the brake include the arm h of the opening force p on the fulcrum, the distance f from the brake shoe support point to the center of the brake base plate, the radius R of the brake drum, the brake shoe lining wrap angle θ, the angle θ1 between the line connecting the brake shoe support point to the center of the brake base plate and the line connecting the lining end point to the center of the brake base plate, the rocker arm angle δ2, the arm a of the opening force p on the camshaft, and the rocker arm length A; Obtaining structural parameters of the brake through overall design; Step 4: Calculate the geometric parameters of the brake; The geometric parameters of the brake include the friction angle γ, the diameter of the pressure center circle l0, the angle α between the maximum brake pressure line and the bisector of the brake shoe lining angle, the angle β between the line connecting the brake pressure center to the center of the brake base plate and the bisector of the brake shoe lining angle, and the angle λ between the equivalent total pressure direction on the brake shoe consistent with the rotation direction of the brake drum and its corresponding fulcrum force arm. t1 , the angle λ between the equivalent total pressure direction of the brake shoe opposite to the rotation direction of the brake drum and its force arm to the fulcrum t2 , the proportional coefficient ζ of the lever arm h relative to the radius R of the brake drum, the proportional coefficient κ of the distance f relative to the radius R of the brake drum, and the proportional coefficient ρ of the pressure center circle diameter l0 relative to the radius R of the brake drum; Step 5: Calculate the efficiency factor K of the brake shoe that rotates in the same direction as the brake drum t1 ; Calculate the efficiency factor K of the brake shoe that rotates in the same direction as the brake drum using formula 12. t1 : In formula 12, ζ is the proportional coefficient of the force arm h to the radius R of the brake drum, κ is the proportional coefficient of the distance f obtained in formula 10 to the radius R of the brake drum, and λ t1 is the angle between the equivalent resultant pressure direction on the brake shoe with the same rotation direction of the brake drum obtained by formula 7 and its corresponding fulcrum lever arm, ρ is the proportional coefficient of the pressure center circle diameter l0 relative to the brake drum radius R obtained by formula 11, β is the angle between the line connecting the brake pressure center to the center of the brake base plate obtained by formula 6 and the bisector of the brake shoe lining angle, and γ is the friction angle obtained by formula 3; Step 6: Calculate the efficiency factor K of the brake shoe that rotates in the opposite direction to the brake drum t2 Calculate the efficiency factor K of the brake shoe that rotates in the opposite direction to the brake drum using formula 13. t2 : In formula 13, λ t2 It is the angle between the direction of the equivalent total pressure of the brake shoe opposite to the direction of rotation of the brake drum and its lever arm to the fulcrum; Step 7: Calculate the brake efficiency factor K t : The brake efficiency factor K is calculated by formula (14) t : K t =K t1 +K t2 (14) Where K t is the efficiency factor of the brake, K t1 is the efficiency factor of the brake shoe with the same rotation direction as the brake drum obtained in step 5; K t2 is the efficiency factor of the brake shoe in the opposite direction of the brake drum rotation obtained in step 6.

10. The method for controlling brake torque of a manned lunar rover according to claim 9, wherein: In step 4: The friction angle γ is obtained by formula (3): γ=arctanμ (3) In Equation 3, μ is the friction coefficient of the friction couple between the brake drum and the brake shoe measured in step 2; The pressure center circle diameter l0 is obtained by formula (4): In Equation 4, θ is the brake shoe lining wrap angle obtained in step 3, and R is the radius of the brake drum obtained in step 3; The angle α between the maximum braking pressure line and the bisector of the brake shoe lining angle is obtained by formula (5): In Equation 5, θ1 is the angle between the line from the brake shoe support point to the center of the brake base plate obtained in step 3 and the line from the end point of the lining to the center of the brake base plate; The angle β between the line connecting the brake pressure center to the center of the brake base plate and the bisector of the brake shoe lining angle is obtained by formula (6): By using formula 7, we can get the angle λ between the direction of the equivalent resultant pressure on the brake shoe, which is consistent with the rotation direction of the brake drum, and its force arm to the fulcrum. t1 ; l t1 =γ+β-α (7) By using formula 8, we can get the angle λ between the equivalent total pressure direction of the brake shoe opposite to the rotation direction of the brake drum and its force arm to the fulcrum. t2 ; l t2 =γ-β+α ((8) The proportional coefficient ζ of the lever arm h relative to the radius R of the brake drum is obtained by formula 9: ζ=h / R (9) In Equation 9, h is the moment arm of the opening force p obtained in step 3 relative to the fulcrum, and R is the radius of the brake drum obtained in step 3. The proportional coefficient κ of the distance f relative to the radius R of the brake drum is obtained using Equation 10: κ=f / R (10) In formula (10), f is the distance from the brake shoe support point to the center of the brake base plate obtained in step 3; The proportional coefficient ρ of the pressure center circle diameter l0 to the brake drum radius R is obtained by formula 11: ρ=l0 / R (11) In formula 11, l0 is the pressure center circle diameter calculated by formula 4.

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