A parachute force balance accuracy testing device

Abstract

This invention discloses a parachute force balance accuracy testing device, comprising a platform, an α-γ body rotatably mounted on the platform, a spindle mounted inside the α-γ body and capable of rotating coaxially with the α-γ body, the α-γ body being able to rotate along the α and γ directions, one end of a balance support rod fixed to the spindle, and the parachute force balance under test fixed to the balance support rod, ensuring that the six calibration loading directions of the parachute force balance under test are always vertically downward. This device features small testing error, high mobility, and high testing efficiency.

Description

Technical Field

[0001] This invention belongs to the field of parachute force balance accuracy testing technology, and particularly relates to a parachute force balance accuracy testing device. Background Technology

[0002] With the rapid development of various types of military aircraft and airborne equipment in my country, parachutes, as a crucial subsystem of these systems, are facing increasingly higher performance requirements and expanding into new application areas. During the development of various parachutes, designers need to understand the aerodynamic performance of different parachute types. After the design of different parachute types is completed, extensive wind tunnel tests are conducted to obtain aerodynamic characteristic test data. Designers then analyze and identify the optimal parachute type based on this data. Currently, parachutes under development or finalized exhibit small aerodynamic design tolerances, leading to continuously increasing demands on the accuracy of wind tunnel testing and the stability of force balances. Statistics from the past decade show a significant increase in the accuracy requirements of parachute wind tunnel testing, with the stability and precision of force balances increasing exponentially. As a crucial aerodynamic sensing and measurement device in parachute wind tunnel testing, the force balance must undergo accuracy testing before wind tunnel testing, as stipulated in the "Wind Tunnel Strain Balance Specification" (GJB2244A-2014). This testing is conducted after the completion of design, fabrication, strain gauge installation, and measurement circuit connection. The accuracy test is used to determine the stability of the force balance's accuracy and ensure the precision and reliability of the data acquired during the parachute test. Furthermore, the increased frequency of use of parachute force balances necessitates more intensive accuracy calibration.

[0003] Commonly used parachute force balance accuracy testing devices are mainly divided into two types of loading coordinate systems: the ground axis system and the body axis system. For parachute force balances, the ground axis system accuracy testing device is primarily used. Currently, the structure of the ground axis system force balance accuracy testing device mainly adopts a frame-type calibration frame and a screw-based circumferential positioning rod type calibration platform. The frame-type calibration frame force balance accuracy testing device mainly completes the loading of the force balance in multiple directions through "fixed pulleys + steel belts + weights," which has the following problems: 1) Many components result in a large footprint; 2) High positioning accuracy between components makes them difficult to move, leading to poor mobility; 3) Due to the friction between the steel belt and the pulleys, there are deviations between the load sensed by the force balance and the mass of the weights, resulting in large accuracy testing errors. The screw-based circumferential positioning rod calibration table mainly uses the loading ring and loading sleeve for circumferential positioning to complete the conversion of the loading direction. Since the circumferential positioning is mainly achieved by screw fastening, the positioning accuracy is poor, resulting in discreteness in the accuracy data. In addition, when the loading direction is converted during accuracy testing, the test personnel need to disassemble a large number of screws, which results in a large workload and low efficiency. Summary of the Invention

[0004] Purpose of the invention

[0005] To overcome the problems of large detection errors and low efficiency in existing parachute force balance accuracy testing devices, this invention provides a parachute force balance accuracy testing device to improve the accuracy of force measurement tests in parachute wind tunnel experiments.

[0006] Invention Technology Solutions

[0007] A parachute force balance accuracy testing device includes a platform, an α-γ body rotatably mounted on the platform, a spindle mounted inside the α-γ body and capable of rotating coaxially with the α-γ body, the α-γ body being able to rotate along the α and γ directions, one end of a balance support rod being fixed to the spindle, and the parachute force balance being tested being fixed to the balance support rod, such that the six calibration loading directions of the parachute force balance being tested are always vertically downward.

[0008] Preferably, the rotation of the α-γ body along the α and γ directions is achieved by a combined worm gear mechanism.

[0009] Preferably, the loading sleeve is fixed to the other end of the balance support rod, and the two crossbeams are fixed radially on the loading sleeve. The two crossbeams and the loading sleeve are connected to form a cross shape, so that the four loading points of the test force balance of the parachute are symmetrically arranged on the loading sleeve, which can realize the rapid switching of the six component accuracy test conditions of the parachute force balance.

[0010] Preferably, a transverse bearing seat is rotatably mounted on the outer side of the end of the crossbeam, and small bearing seats are rotatably mounted on the outer sides of both ends of the transverse bearing seat. A connecting block B is fixed to the small bearing seats on the transverse bearing seat. A longitudinal bearing seat is rotatably mounted on the end of the loading sleeve along the radial direction, and small bearing seats are rotatably mounted on the outer sides of both ends of the longitudinal bearing seat. A connecting block A is fixed to the small bearing seats on the longitudinal bearing seat. Both connecting blocks B and A are connected to the loading rod, and a weight pan is connected to the bottom of the loading rod. This ensures the accuracy of the loading angle of the balance support rod under various loading conditions and reduces the loading error of the six components of the force balance of the parachute being tested.

[0011] Preferably, the worm gear mechanism is self-locking and includes an α-worm, a γ-worm, an α-worm, and a γ-worm shaft; the α-worm is connected to the α-γ body, and the α-worm, which is rotatably mounted on the platform, engages with the α-worm; the γ-worm is connected to the spindle, and the γ-worm, which is rotatably mounted on the α-γ body, engages with the γ-worm.

[0012] Preferably, the α turbine and γ turbine are sawtooth turbines, and the α worm and γ worm gear are sawtooth turbine rods.

[0013] Preferably, the inner hole of the mandrel and the balance rod are fitted by a tapered surface and secured in both directions by a two-way nut.

[0014] Preferably, the dial is coaxially fixed on the γ turbine.

[0015] Preferably, the fixed end of the test parachute force balance is fixed to the inner conical hole of the balance support rod by a two-way nut, the two crossbeams are fixed to the loading sleeve by positioning supports, the inner conical hole of the slider is connected to the loading end of the test parachute force balance by plug gauge, the slider and the loading sleeve are precisely positioned and connected by positioning pin, and the connection is tightened by screwing standard screws into the threaded hole of the slider and the threaded hole of the loading end of the parachute force balance.

[0016] Advantages of the present invention: The device has small detection error, high mobility and high detection efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a preferred embodiment of the parachute force balance accuracy detection device of the present invention.

[0018] Figure 2 This is a schematic diagram of a half-section front view of the parachute force balance accuracy detection device of the present invention.

[0019] Figure 3 This is a schematic diagram of a half-section left view of the parachute force balance testing device of the present invention.

[0020] Figure 4 Enlarged half-section view of the assembly connection of the loading sleeve, positioning support, lateral support, small bearing housing and transverse bearing housing.

[0021] Figure 5 This is a half-sectional schematic diagram of the platform structure equipped with the α worm gear and bearing end cap.

[0022] Figure 6 Schematic diagram of the structure of α-γ body

[0023] Figure 7 This is a schematic diagram of the mandrel structure.

[0024] Figure 8 This is a schematic diagram of the structure of the loading sleeve.

[0025] Figure 9 This is a schematic diagram of the α worm gear.

[0026] Figure 10 This is an enlarged half-section view of the assembly connection of the crossbeam, longitudinal bearing housing, small bearing cover, small end cover, loading rod, bearing end cover, and connecting block B.

[0027] In the diagram, 1-platform, 2-support base, 3-α worm gear, 4-locking nut A, 5-end cover A, 6-γ worm, 7-γ worm shaft, 8-scale, 9-locking nut B, 10-spindle, 11-α-γ body, 12-locking nut C, 13-shield, 14-γ bearing end cover, 15-positive and negative nuts, 16-balance support rod, 17-connecting block A, 18-small bearing seat, 19-small bearing seat 20-Small end cap, 21-Connecting block B, 22-Loading rod, 23-Weight pan, 24-Transverse bearing seat, 25-Longitudinal bearing seat, 26-Double-direction nut, 27-Positioning pin, 28-α shaft end cap, 29-Slider, 30-α turbine, 31-Crossbeam, 32-Loading sleeve, 33-End cap B, 34-Positioning support, 35-Side support, 36-α shaft upper cap, 37-Bearing end cap. Detailed Implementation

[0028] The present invention is achieved through the following technical solution.

[0029] A parachute force balance accuracy testing device, characterized in that the device comprises a platform 1, a support base 2, an α worm gear 3, a locking nut A4, an end cap A5, a γ turbine 6, a γ worm shaft 7, a scale 8, a locking nut B9, a spindle 10, an α-γ body 11, a locking nut C12, a bushing 13, a γ bearing end cap 14, positive and negative nuts 15, a balance support rod 16, a connecting block A17, a small bearing seat 18, a small bearing seat cover 19, a small end cap 20, a connecting block B21, a loading rod 22, a weight pan 23, a transverse bearing seat 24, a longitudinal bearing seat 25, a bidirectional nut 26, a positioning pin 27, an α shaft end cap 28, a slider 29, an α turbine 30, a crossbeam 31, a loading sleeve 32, an end cap B33, a positioning support 34, a lateral support 35, an α shaft upper cover 36, and a bearing end cap 37.

[0030] Platform 1 is a load-bearing platform for mounting base 2, α worm gear 3, γ turbine 6, and α-γ body 11. The overall structure of platform 1 adopts an inverted "T" shape, with reinforcing ribs at the base to increase overall structural strength. The upper side of the boss portion of platform 1 has semi-circular through holes, the diameter of which is larger than the diameter of the threaded cylindrical bosses on the left and right sides of α-γ body 11. A bracket for mounting α worm gear 3 is provided on the right side of platform 1. The bottom of platform 1 has three internally threaded holes for mounting base 2, arranged in an isosceles triangular layout.

[0031] Support base 2 is a support component used to enhance the stability of platform 1 under load. Support base 2 mainly consists of a manual lever, a special-shaped screw with a ball end, and a base. The base adopts a trapezoidal layout, with the diameter of the upper hole equal to the diameter of the ball end. The special-shaped screw with a ball end has a limiting groove radially provided on the ball end, and a through hole drilled on the side of its other end face for the manual lever to pass through. The manual lever is a commonly used pin.

[0032] The α worm gear 3 is a cylindrical worm gear with a square boss at the left end, a threaded boss at the right end, and a serrated worm shaft in the middle. Four levels of cylindrical bosses are arranged between the square boss and the serrated worm shaft. The first level cylindrical boss on the left is for positioning the standard handwheel; the second level is a threaded boss for threaded connection with the lock nut A4; the third level cylindrical boss on the left is for positioning the standard deep groove ball bearing; and the fourth level cylindrical boss on the left is for reducing the rotational inertia of the α worm gear 3. Three levels of cylindrical bosses are arranged between the serrated worm shaft and the threaded boss. The first level on the right is a threaded boss for threaded connection with the lock nut B9; the second level cylindrical boss on the right is for the standard deep groove ball bearing; and the third level cylindrical boss on the right is also for reducing the rotational inertia of the α worm gear 3. The diameter of the third level cylindrical boss on the right is the same as that of the fourth level cylindrical boss on the left. The middle section of the α worm gear 3 is a sawtooth turbine rod with a pressure angle of 20° and a right rotation direction. The module and number of teeth of the sawtooth are precisely matched with the α turbine 30 to achieve the corresponding values.

[0033] Locking nuts A4, B9, and C12 are a type of irregularly shaped nut, with four circumferentially distributed rectangular grooves on the radial direction of the outer circle, which facilitates tightening in confined spaces.

[0034] End cap A5 is a disc-shaped cover plate used to connect α worm 3. End cap 5 has four countersunk holes distributed in the radial direction. The countersunk holes are used for screw fastening connection between end cap 5 and the right side bracket of platform 1 to ensure that the α worm 3 is reliably positioned on the right side bracket of platform 1.

[0035] The γ-turbine 6 is a component that works with the γ-worm gear 7 to perform worm gear transmission. A through hole is provided at the center of the γ-turbine 6, and the diameter of the through hole is approximately 1 / 2 of the outer diameter of the γ-turbine 6. A cylindrical hollow boss is provided at the center of the γ-turbine 6, and the inner diameter of the boss is equal to that of the through hole at the center of the γ-turbine 6. The boss is fitted into the mandrel 10 with an interference fit.

[0036] The γ-worm gear 7 is a cylindrical worm gear with a threaded boss at the left end, a square boss at the right end, and a serrated worm shaft in the middle. Four levels of cylindrical bosses are arranged between the square boss and the serrated worm shaft. The first level cylindrical boss on the right is used to position the standard handwheel; the second level is a threaded boss for threaded connection with the lock nut C12; the third level cylindrical boss is used to position the standard deep groove ball bearing; and the fourth level cylindrical boss is used to reduce the rotational inertia of the γ-worm gear 7. Three levels of cylindrical bosses are arranged between the serrated worm shaft and the threaded boss. The first level on the left is a threaded boss for threaded connection with the lock nut C12; the second level cylindrical boss on the left is used to limit the positioning of the standard deep groove ball bearing; and the third level cylindrical boss on the left, also for reducing the rotational inertia of the γ-worm gear 7, has the same diameter as the fourth level cylindrical boss on the left. The middle section of the γ-vortex 7 is a sawtooth turbine rod with a pressure angle of 20° and a right rotation direction. The module and number of heads of the sawtooth are precisely matched with the γ-vortex 6 to achieve the corresponding values.

[0037] The dial 8 is coaxially mounted on the γ turbine 6, and the dial 8 is marked with angle markings from 0° to 360° at a 1:1 scale. The dial 8 has four circumferentially distributed countersunk holes in the radial direction for fastening the dial 8 and the γ turbine 6 together with countersunk screws.

[0038] The mandrel 10 is a non-standard hollow shaft. The left first-stage boss is a threaded boss, the left second-stage boss is a cylindrical boss, the left third-stage boss is a threaded boss, and the left fourth-stage boss is a cylindrical boss. The right first-stage boss is a threaded boss, the right second-stage boss is a threaded boss, and the right third-stage boss is a cylindrical boss. A keyway is provided on the left second-stage cylindrical boss of the mandrel 10. A 1:5 internal tapered hole is provided at the right end of the hollow area of ​​the mandrel 10, and the internal tapered hole is configured with a plug gauge. The left first-stage threaded boss of the mandrel 10 is tightened with two locking nuts B9, and the right end tapered hole of the hollow area of ​​the mandrel 10 has a 1:5 taper fit with the balance support rod 16. The third-stage boss on the left of the spindle 10 is tightened to the locking nut C12 and is used to limit the γ turbine 6. The fourth-stage boss on the left is used to limit the standard deep groove ball bearing. The first-stage boss on the right is tightened to the positive and negative nuts 15. The second-stage threaded boss on the right is tightened to the locking nut B9. The three cylindrical bosses on the right are also used to limit the standard deep groove ball bearing.

[0039] The α-γ body 11 is an integral casting with multi-stage stepped bosses on both sides, a γ worm gear 7 mounting bracket on the upper part, and a cylindrical shape in the middle. Six threaded holes are circumferentially distributed on the outer diameter plane of the cylinder for connection with the γ bearing end cap 14. Multi-stage bosses are provided on both sides of the centerline of the α-γ body 11, with four stages on the left and six stages on the right. The first stage boss on the left is a threaded boss, while the second, third, and fourth stages are cylindrical bosses. The second and third stages are fitted into the standard tapered roller bearing, with the fourth stage boss providing a limiting position. The first stage threaded boss is tightened with the lock nut C12 to restrict axial movement of the standard tapered roller bearing. The first stage boss on the right is a threaded boss, the second stage boss is a cylindrical boss, and a keyway is formed on the upper end face. The third stage boss on the right is a threaded boss, while the fourth, fifth, and sixth stages are cylindrical bosses. The right-first-stage threaded boss is fastened to two locking nuts C12. The right-second-stage boss and the α-turbine 30 are fitted together and connected, with a standard key for positioning. The right-third-stage threaded boss is tightened to the locking nut C12. The right-fourth and right-fifth-stage bosses are fitted into standard tapered roller bearings and positioned using the right-sixth-stage boss. Circular through holes are provided on both sides of the upper end face of the mounting bracket for the α-γ body 11. The diameter of the through holes is larger than the maximum outer diameter of the γ-worm 7. The outer diameter areas of the circular through holes on both sides correspond to the γ-bearing end cap 14.

[0040] Bushing 13 is a tubular component that is interference-fitted into α-γ body 11 and is used to limit the installation of standard deep groove ball bearings at the left and right ends of spindle 10.

[0041] The γ bearing end cover 14 is a disc-shaped cover plate, which is connected to the α-γ body 11 by countersunk screws and six threaded holes.

[0042] The positive and negative nut 15 is a non-standard nut. After the mandrel 10 is inserted into the α-γ body 11 and locked, the balance support rod 16 is connected to the mandrel 10 with a tapered fit. The positive and negative nut 15 is inserted into the joint of the mandrel 10 and the balance support rod 16 for threaded fastening connection.

[0043] The balance support rod 16 is an irregularly shaped hollow rod-shaped component. The outer surface on the left side has an outer cone with a 1:5 taper, and the inner surface on the right side has an inner cone with a 1:5 taper. The outer cone on the left side is taper-fitted to the inner conical hole of the mandrel 10, and the inner cone on the right side is taper-fitted to the cone of the test parachute force balance.

[0044] Both connecting block A17 and connecting block B21 are inverted trapezoidal metal connecting blocks, with three through holes on the upper end face, which are fastened to the small bearing seat 18 with nuts.

[0045] The small bearing housing 18 is a special-shaped screw with a circular groove at the upper end and a screw at the lower end. The outer diameter area of ​​the circular groove is provided with 6 threaded holes distributed in a circle. The 6 threaded holes of the small bearing housing 18 are fastened to the small bearing housing end cap 19 by standard countersunk screws.

[0046] The small bearing housing end cover 19 is a disc cover plate with a boss, and the upper panel is provided with circumferentially distributed through holes.

[0047] The small end cap 20 is a disc cover plate with a countersunk hole at the center.

[0048] The loading rod 22 is a long screw rod, one end of which is fastened to the connecting block A17 and the connecting block B21 by a nut, and the other end is also fastened to the weight pan 23 by a nut.

[0049] The weight pan 23 is a tray for holding weights.

[0050] The transverse bearing housing 24 is an irregularly shaped ring with cylindrical bosses at both the upper and lower ends. The upper and lower bosses are connected to the small bearing housing 18, and the central ring is connected to the small end cap 20, the crossbeam 31, and the end cap 33.

[0051] The longitudinal bearing housing 25 is an irregularly shaped ring with cylindrical bosses at both the upper and lower ends. The upper and lower bosses are connected to the small bearing housing 18, and the central ring is connected to the small end cap 20, the loading sleeve 32, and the end cap 33.

[0052] The bidirectional nut 26 is a cylindrical nut with internal threads of both positive and negative orientations and an outer surface with 1.5mm clearance knurling. It is used to connect the mandrel 10 and the fixed end of the force balance of the test parachute.

[0053] The positioning pin 27 is a special-shaped pin used to limit and fix the loading sleeve 32 and the loading end of the force balance of the test parachute.

[0054] α-shaft end cap 28 is a disc cover plate with a through hole at the center.

[0055] The slider 29 is an irregularly shaped cone cap used to connect the parachute force balance under test and the loading sleeve 32.

[0056] The α-turbine 30 is a component that works with the α-worm gear 3 to perform a worm gear transmission. A through hole is located at the center of the α-turbine 30, with a diameter approximately half the outer diameter of the α-turbine 30. A cylindrical hollow boss is located at the center of the α-turbine 30, with an inner diameter equal to that of the through hole at the center of the α-turbine 30. The boss fits into the right secondary boss of the α-γ body 11 with an interference fit.

[0057] The crossbeam 31 is used to connect with the positioning support 34.

[0058] The loading sleeve 32 is used to connect with the positioning support, and each end of the loading sleeve 32 is connected to a longitudinal bearing seat 25.

[0059] End cap B33 is a special-shaped nut that connects to the two ends of crossbeam 31 and has knurling with a 1.5mm gap on the outside.

[0060] The positioning support 34 is a square block with a through hole in the middle. The diameter of the through hole is equal to the outer diameter of the loading sleeve 32. The positioning support 34 has countersunk holes on both sides, and six circumferentially distributed threaded holes are formed around the outer ring of the countersunk holes. The upper end face of the positioning support 34 has two tapered holes.

[0061] The lateral support 35 is a crescent-shaped block with two countersunk holes and two tapered holes symmetrically opened on its side along the vertical center line. The inner side has an arc, which fits snugly against the outer wall of the loading sleeve 32.

[0062] The α-axis cover 36 is an arched cover plate used to fix the α-γ body 11 to the platform 1.

[0063] The bearing end cover 37 is a cover plate for a deep groove ball bearing with a cylindrical boss, and the lower end face is provided with four circumferentially distributed countersunk holes.

[0064] Platform 1 is a load-bearing platform for mounting base 2, α worm gear 3, γ turbine 6, and α-γ body 11. It is a single-piece casting made of gray cast iron. The vertical section of platform 1 has square holes for weight reduction, and the bottom end face has square holes of different sizes to reduce the weight of platform 1 and improve its mobility. Threaded holes for mounting α-γ body 11 are provided on both sides of the upper end face of the vertical section of platform 1. The rigidity of platform 1 is greater than twice the loading range requirement of the force balance of the parachute being tested.

[0065] The support base 2 is connected to the platform 1 by threads. By adjusting the thread length of the three support bases 2 respectively, the platform 1 is ensured to be in a flat position. The inverted trapezoidal base of the support base 2 can increase the contact area with the ground, improve the placement stability of the platform 1, and improve the mechanical response of the six components of the parachute force balance under load.

[0066] The mandrel 10 is fitted into the α-γ body 11. A deep groove ball bearing is fitted into each of the left and right bosses of the mandrel 10, and two locking nuts B9 are used to lock the two deep groove ball bearings respectively. A bushing 13 is fitted between the two deep groove ball bearings to ensure that the α-γ body 11 and the mandrel 10 rotate coaxially. After the α-γ body 11 is connected to the mandrel 10, it provides a rotation platform for adjusting the mandrel 10 in the γ direction from 0° to 360°.

[0067] The α worm gear 3 and α turbine 30 are connected via a worm gear assembly method with a precision of grade 7. The γ turbine 6 and γ worm gear 7 are also connected via a worm gear assembly method with a precision of grade 7. After the α worm gear 3 and α turbine 30 are connected via the worm gear assembly method, a 0° angle in the α-γ body 11α direction can be achieved.

[0068] A rotary transmission mechanism provides fine adjustment up to -120°. The γ-turbine 6 and γ-worm gear 7 are connected via a worm gear assembly, enabling fine adjustment of the spindle 10 γ-direction from 0° to 360°, thus providing a rotary transmission mechanism. Self-locking is achieved by controlling the worm gear helix angle, ensuring the accuracy of the angle of the balance support rod 16 under load.

[0069] The crossbeam 31 and the loading sleeve 32 are connected by the positioning support 34 to form a "cross-shaped" loading system, ensuring that the four loading points of the force balance for the parachute test are symmetrically arranged on the loading sleeve 32. The transverse bearing seat 24 is fitted into the limiting boss at the outer end of the crossbeam 31, and a standard deep groove ball bearing is embedded in the transverse bearing seat 24. The standard deep groove ball bearing embedded in the transverse bearing seat 24 is limited on the outside by the end cap B33. Two small bearing seats 18 are respectively fitted into the upper and lower limiting bosses of the transverse bearing seat 24. Two standard deep groove ball bearings are embedded in the small bearing seats 18, and small bearing caps 19 and small end caps 20 are respectively connected to the small bearing seats 18. The connecting block B21 is fastened to the two transverse bearing seats 24 installed on the crossbeam 31 by upper and lower double nuts. By rotating these two mutually perpendicular parts in the horizontal dimension, the calibration loading direction of the parachute force balance being tested is always vertically downward, and the accuracy calibration conditions of the lift and negative drag units of the parachute force balance can be quickly switched.

[0070] The loading sleeve 32 is fitted with the limiting bosses at both ends of two longitudinal bearing seats 25, and standard deep groove ball bearings are embedded in the longitudinal bearing seats 25. End caps B33 are used to fix and limit the standard deep groove ball bearings embedded in the longitudinal bearing seats 25. Two small bearing seats 18 are fitted with the upper and lower limiting bosses of the longitudinal bearing seats 25, respectively. Two standard deep groove ball bearings are embedded in the small bearing seats 18, and small bearing caps 18 and small end caps 20 are used to connect them to the small bearing seats 18. Connecting blocks A17 are fastened to the two longitudinal bearing seats 25 installed on the loading sleeve 32 with double nuts. Through these two mutually perpendicular rotations in the longitudinal dimension, the calibration loading direction of the tested parachute force balance is always vertically downward, allowing for quick switching between the negative resistance and rolling torque unit accuracy calibration conditions of the parachute force balance.

[0071] The balance rod 16 and the spindle 10 are fitted with a 1:5 taper to improve connection precision and achieve fast mechanical transmission response when a standard source load is applied. A lateral support 35 is provided at the joint between the balance rod 16 and the loading sleeve 32 to improve the overall rigidity of the loading sleeve 32.

[0072] exist Figures 1-10In the process, place platform 1 flat on the ground, install support base 2 in the mounting hole of platform 1, and adjust the pin of support base 2 to ensure that the base part of platform 1 is parallel to the ground. Insert the bosses on the left and right sides of α-γ body 11 into the two semi-circular holes of the column part of platform 1. Fit standard tapered roller bearings into the bosses on both sides of α-γ body 11, and lock them with two lock nuts C12 on each side. Then connect the α shaft cover 36 to the threaded holes on the end face of the column part of platform 1 through standard screws. Fit the α turbine 30 into the right boss of α-γ body 11, and fasten it with two lock nuts C12 and standard key. A γ-worm gear 7 is installed on the mounting bracket of the α-γ body 11. Two standard deep groove ball bearings are installed from the outside and secured with two lock nuts C12. Two bearing end caps 37 are connected to the threaded holes on both sides of the mounting bracket of the α-γ body 11 with screws. The standard handwheel is fitted onto the square boss on the right side of the γ-worm gear 7. The γ bearing end cap 14 is threaded to the left end face of the cylindrical part in the α-γ body 11 and secured with countersunk screws. A standard deep groove ball bearing is fitted onto the boss on the left end of the spindle 10 and secured with lock nut B9. A bushing 13 is fitted onto the right end of the spindle 10, and another standard deep groove ball bearing is fitted onto the boss on the right end of the spindle 10, also secured with lock nut B9. Insert the assembled mandrel 10 into the cylindrical inner circle of the α-γ body 11. Secure the other γ bearing end cap 14 to the right end of the cylindrical portion of the α-γ body 11 with countersunk screws, ensuring the threads are flush. Insert the γ turbine 6 into the mandrel 10. The gear of the γ turbine 6 and the γ worm gear 7 are precisely meshed. Install the standard key into the keyway of the axial limiting area of ​​the γ turbine 6 and the mandrel 10, and tighten it with two lock nuts A4. Align the dial 8 with the threaded hole of the γ turbine 6 and secure it with countersunk screws. Connect the gear of the α worm gear 3 to the gear of the α turbine 30, and then insert it into the two mounting holes of the side bracket of the platform 1. Insert a standard deep groove ball bearing from the left end of the α worm gear 3 and tighten it with lock nuts A4. Also insert a standard deep groove ball bearing from the right end of the α worm gear 3 and tighten it with lock nuts A4. Connect the end cap A5 to the two end faces of the two mounting holes on the side bracket of the platform 1 using countersunk screws. Insert the standard handwheel onto the square boss of the α worm gear 3. Insert the balance support rod 16 into the right-end conical hole of the mandrel 10, and use the double-nut 15 to connect the balance support rod 16 and the mandrel 10 to the threaded area, then tighten the connection with the double-nut 15. Pre-tighten the double-ended nut 26 into the right-end thread of the balance support rod 16, insert the fixed end of the parachute force balance to be tested into the right-end inner conical hole of the balance support rod 16, and tighten the double-ended nut 26. Insert the conical hole of the slider 29 into the loading end of the parachute force balance to be tested, and tighten it with the screw.First, fit the left end of the loading sleeve 32 into a longitudinal bearing seat 25, and embed a standard deep groove ball bearing into the longitudinal bearing seat 25. Use an end cap B33 on each of the two outer sides to fix and limit the standard deep groove ball bearing embedded in the longitudinal bearing seat 25. Fit the two small bearing seats 18 into the upper and lower limiting bosses of the longitudinal bearing seat 25, respectively. Embed two standard deep groove ball bearings into the small bearing seats 18, and connect them with the small bearing seats 18 with the small bearing cap 18 and the small end cap 20, respectively. Secure the connecting block A17 to the two longitudinal bearing seats 25 installed on the loading sleeve 32 with double nuts. After assembly, fit the loading sleeve 32 into the balance support rod 16 of the force balance of the parachute being tested, align the mounting holes of the loading sleeve 32 and the slider 19, and fix them in place with screws and positioning pins 27. Place the positioning support 34 onto the geometric center limiting boss of the loading sleeve 32, align the positioning cone holes of the positioning support 34 and the loading sleeve 32, and drive in a standard part shaft pin for positioning and fixation. Place another longitudinal bearing seat 25 onto the right end of the loading sleeve 32, and embed a standard part deep groove ball bearing into the longitudinal bearing seat 25. Use an end cap B33 on each of the two outer sides to fix and limit the standard part deep groove ball bearing embedded in the longitudinal bearing seat 25 to the left and right. Then, place two small bearing seats 18 onto the upper and lower limiting bosses of the longitudinal bearing seat 25 respectively, and embed two standard part deep groove ball bearings into the small bearing seats 18. Connect the small bearing seats 18 with small bearing caps 18 and small end caps 20 respectively. Another connecting block A17 is fastened to the two longitudinal bearing seats 25 installed on the loading sleeve 32 with double nuts. The transverse bearing housing 24 is fitted onto the limiting boss at the outer end of the crossbeam 31, and a standard deep groove ball bearing is embedded in the transverse bearing housing 24. The standard deep groove ball bearing embedded in the transverse bearing housing 24 is limited on the outside by the end cap B33. Two small bearing housings 18 are respectively fitted onto the upper and lower limiting bosses of the transverse bearing housing 24, and two standard deep groove ball bearings are embedded in the small bearing housings 18. The small bearing caps 18 and small end caps 20 are respectively connected to the small bearing housings 18. The connecting block B21 is fastened to the two transverse bearing housings 24 installed on the crossbeam 31 by upper and lower double nuts. Align one beam 31, equipped with a transverse bearing seat 24, a small bearing seat 18, and a small end cap 20, with the limiting groove and circumferentially distributed threaded holes of the positioning support 34, and fasten it with screws. Similarly, align another beam 31, also equipped with a transverse bearing seat 24, a small bearing seat 18, and a small end cap 20, with the limiting groove and circumferentially distributed threaded holes of the positioning support 34, and fasten it with screws. Align the two lateral supports 35 with the four side wall holes on the outer side of the loading sleeve 32, and fasten them with standard pins and screws. The loading unit of the parachute test balance being tested fastens one end of the loading rod 22 to the connecting block A17 or the connecting block B21 with a nut, and the other end is also fastened to the weight pan 23 with a nut.Next, connect the two end caps B33 to the crossbeam 31, which is equipped with the transverse bearing seat 24, the small bearing seat 18, and the small end cap 20, respectively, using countersunk screws. At this point, the parachute force balance accuracy testing device is fully assembled.

[0073] Example

[0074] In 2020, the accuracy test of a six-component force balance for a certain type of stabilized parachute was successfully carried out, with significant experimental results. Based on the design parameters of the test balance, including its structural form and load values ​​from 0 to 80 kgf, components such as the platform, Φ140 mm mandrel, Φ330 α turbine, and Φ120 α worm gear were designed. The fastening connections of the relevant designed components were completed, and the force source adopted a level 3 precision weight loading method.

[0075] The specific experimental procedure is as follows: Adjusting the α turbine according to the coordinate definition of the Earth's axis system so that the α angle of the measured balance is 0°, and adding predetermined weights to the two weight pans in the X direction and the two weight pans in the Z direction respectively, allows for the accuracy detection of the negative lift element, positive and negative roll torque element, and positive and negative pitch distance element of the measured parachute balance. Adjusting the γ turbine by 180° allows for the accuracy detection of the positive lift element of the measured parachute balance. Adjusting the α turbine so that the α angle of the measured balance is 90°, with the longitudinal weight pan empty and the transverse weight pan loaded, allows for the accuracy detection of the positive drag element, positive and negative yaw distance element, and positive and negative lateral force element under the action of gravity, as the transverse bearing seat on the cross-shaped loading sleeve flips.

[0076] The accuracy test of the six components of the force balance of the tested stabilizing parachute was successfully completed according to the work process. The accuracy of the six components of the tested balance was 0.1% to 0.5%. By comparing the balance calibration accuracy with the accuracy index of the strain balance (GJB2244A-2011), the accuracy data met the requirements. The obtained accuracy data provided important support for the refined aerodynamic testing of this type of stabilizing parachute.

[0077] The scope of protection of this invention is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its scope. If such modifications and variations fall within the scope of the claims of this invention and their equivalents, then the intent of this invention also includes these modifications and variations.

Claims

1. A parachute force balance accuracy testing device, characterized in that, The system includes a platform (1), an α-γ body (11) rotatably mounted on the platform (1), a spindle (10) mounted inside the α-γ body (11) and coaxially rotating with the α-γ body (11), the α-γ body (11) being able to rotate along the α and γ directions, one end of a balance support rod (16) fixed on the spindle (10), and the force balance of the parachute being tested fixed on the balance support rod (16), ensuring that the six calibration loading directions of the force balance of the parachute being tested are always vertically downward; the α-γ body (11) is rotated along the α and γ directions through a combined worm gear mechanism; a loading sleeve (32) is fixed on the other end of the balance support rod (16), and two crossbeams (31) are radially fixed on the loading sleeve (32), the two crossbeams (31) and the loading sleeve (32) are connected The four loading points of the parachute force balance being tested are symmetrically arranged on the loading sleeve (32) in a cross shape; a transverse bearing seat (24) is rotatably set on the outer side of the end of the crossbeam (31), and small bearing seats (18) are rotatably set on the outer side of both ends of the transverse bearing seat (24). The small bearing seats (18) on the transverse bearing seat (24) are fixed to the connecting block B (21); a longitudinal bearing seat (25) is rotatably set on the end of the loading sleeve (32) in a radial direction, and small bearing seats (18) are rotatably set on the outer side of both ends of the longitudinal bearing seat (25). The small bearing seats (18) on the longitudinal bearing seat (25) are fixed to the connecting block A (17); both connecting block B (21) and connecting block A (17) are connected to the loading rod (22), and the bottom of the loading rod (22) is connected to the weight pan (23).

2. The parachute force balance accuracy testing device as described in claim 1, characterized in that, The worm gear mechanism can achieve self-locking. The worm gear mechanism includes an α worm (30), a γ worm (6), an α worm (3), and a γ worm (7). The α worm (30) is connected to the α-γ body (11), and the α worm (3) rotatably set on the platform (1) cooperates with the α worm (30). The γ worm (6) is connected to the spindle (10), and the γ worm (7) rotatably set on the α-γ body (11) cooperates with the γ worm (6).

3. The parachute force balance accuracy testing device as described in claim 2, characterized in that, The α turbine (30) and γ turbine (6) are sawtooth turbines, and the α worm (3) and γ worm (7) are sawtooth turbine rods.

4. The parachute force balance accuracy testing device as described in claim 3, characterized in that, The inner hole of the mandrel (10) and the balance rod (16) are fitted together by a tapered surface.

5. The parachute force balance accuracy testing device as described in claim 4, characterized in that, The dial (8) is coaxially fixed on the γ turbine (6).

6. The parachute force balance accuracy testing device as described in claim 5, characterized in that, The fixed end of the test parachute force balance is fixed on the inner conical hole of the balance support rod (16). The two crossbeams (31) are fixed on the loading sleeve (32) through the positioning support (34). The inner conical hole of the slider (29) is connected to the loading end of the test parachute force balance through the fit of the plug gauge. The slider (29) and the loading sleeve (32) are connected by the positioning pin (27).

7. The parachute force balance accuracy testing device as described in claim 6, characterized in that, The spindle (10) and the balance support rod (16) are fastened in both directions by a two-way nut (26).

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