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CN-115931348-B - Test device for testing FAST reflecting surface unit 1# connecting mechanism

CN115931348BCN 115931348 BCN115931348 BCN 115931348BCN-115931348-B

Abstract

The invention relates to a test device for testing a 1# connecting mechanism of a FAST reflecting surface unit, which comprises a rotating frame supporting table, a fixed hinge support, a hinge shaft, a rotating frame, weights, a weight tray, a 1# node shaft test piece, a positive pressure measuring device, a servo sliding table and the like, wherein the device applies positive pressure to an inner ring hole of a joint bearing arranged in a bearing seat of the 1# connecting mechanism through a fixed hinge, the rotating frame, the weights and the 1# connecting mechanism test piece shaft, and the simulated FAST reflecting surface unit applies positive pressure to the 1# connecting mechanism through gravity. The temperature sensor is used for measuring the temperature of the linear sliding bearing, the force sensor connected between the screw nut and the sliding table is used for measuring the friction force, the reciprocating linear motion of the 1# connecting mechanism is simulated through the reciprocating linear motion of the servo sliding table, so that the friction coefficient mu of the linear sliding bearing can be measured, and the service life of the 1# connecting mechanism linear sliding bearing is tested through the reciprocating motion times of the servo sliding table.

Inventors

  • LI HUI
  • YANG QINGGE
  • SONG LIQIANG

Assignees

  • 中国科学院国家天文台

Dates

Publication Date
20260512
Application Date
20221214

Claims (6)

  1. 1. A test device for testing a FAST reflecting surface unit 1# connection mechanism is characterized by comprising a rotating frame supporting table (1), a fixed hinge support (3), a hinge shaft (4), a rotating frame (6), weights (9), a weight tray (10), a 1# node shaft test piece (12), a positive pressure measuring device (15), a servo sliding table (16) and a servo sliding table supporting table (18), wherein the rotating frame supporting table (1) is provided with the fixed hinge support (3), the rotating frame (6) is connected with the fixed hinge support (3) through the hinge shaft (4), a node shaft connecting rod (58) of the 1# node shaft test piece (12) is fixedly connected with a lower chord member of the rotating frame (6), a bearing seat test piece (13) of the 1# node shaft test piece (12) is arranged on the servo sliding table (16), the servo sliding table (16) is arranged on the servo sliding table supporting table (18), the tray (10) is hoisted on the rotating frame (6), the weights (9) are arranged on the bearing seat (10), and the positive pressure measuring device (15) is arranged on the servo sliding table (18) and is arranged on the servo sliding table (13) and is positioned above the test piece; A conical nest (59) is arranged on a node shaft connecting rod (58) of the No. 1 node shaft test piece (12), the No. 1 node shaft test piece (12) is tightly connected with a lower chord hole of the rotating frame (6) through a conical end set screw (11), and the conical end set screw (11) is tightly propped against the conical nest (59) of the node shaft connecting rod (58); The positive pressure measuring device (15) comprises a hanging belt (39), a lifting screw (40), a force sensor (41), a force sensor connecting block (42), a bracket (43), a bolt (44) and a nut (45), wherein the force sensor connecting block (42) is hung on a cross beam of the bracket (43) through the bolt (44) and the nut (45), the force sensor (41) is connected with the force sensor connecting block (42) through threads, the lifting screw (40) is connected with a threaded hole at the lower part of the force sensor (41) through threads, the lifting screw (40) is connected with the hanging belt (39), and the hanging belt (39) hangs the journal of a No. 1 node shaft (57) of the No. 1 node shaft test piece (12) at a hanging position (38) of a No. 1 node shaft; The servo sliding table (16) is fixedly connected to the servo sliding table supporting table (18) through bolts, the bearing seat test piece (13) is fixedly connected to a workbench (24) of the servo sliding table (16) through 2 plain washers (19), 2 spring washers (20) and 2 hexagon socket screws (21), and the hexagon socket screws (21) penetrate through 2 bolt holes of a 1# bearing seat (64) of the 1# node shaft test piece (12); the 1# connecting mechanism test piece comprises a 1# node shaft test piece (12), a bearing seat test piece (13), a gasket (62) and a bolt (63); The 1# node shaft test piece (12) comprises a 1# node shaft (57) and a node shaft connecting rod (58), wherein the 1# node shaft (57) is connected with the node shaft connecting rod (58), and a conical nest (59) is processed on the node shaft connecting rod (58) and is used for fixedly connecting the 1# node shaft test piece (12) with the rotating frame (6); The bearing seat test piece (13) comprises a 1# bearing seat (64), a joint bearing (60) and a PTFE fabric pad (61), wherein the PTFE fabric pad (61) is arranged on the inner ring of the joint bearing (60), a steel-PTFE friction pair is formed by a 1# node shaft (57) and the inner ring of the joint bearing (60), a gasket (62) and a bolt (63) are arranged at the end part of the 1# node shaft (57), and the bolt (63) is connected with a temperature sensor (14).
  2. 2. The test device according to claim 1, wherein the servo slide table (16) is composed of a servo slide table seat (27), a linear rolling guide rail pair (22), a workbench (24), a ball screw pair (28), a synchronous pulley (29), a synchronous belt (30), a motor bracket (31), a servo motor (32), an inner hexagonal screw (33), a force sensor connecting washer (34), a force sensor (35) and a screw nut (36), wherein a guide rail of the linear rolling guide rail pair (22) is mounted on the servo slide table seat (27), the workbench (24) is mounted on a slide block of the linear rolling guide rail pair (22), the workbench (24) slides along the guide rail of the linear rolling guide rail pair (22), the ball screw pair (28) is mounted on the servo slide table seat (27), a screw of the ball screw pair (28) is supported at both ends by bearing blocks, the synchronous pulley (29) is mounted at a screw power input end, the servo slide table (27) is mounted with the motor bracket (31) for supporting the servo motor (32), a synchronous pulley (29) is mounted on a shaft of the servo motor (32), the ball screw pair (28) is connected with the synchronous pulley (30) by the synchronous pulley (30), the servo motor (32) drives a ball screw of the ball screw pair (28) to rotate through the synchronous belt (30), the ball screw drives a screw nut (36) to do linear motion, the screw nut (36) is connected with the workbench (24) through a force sensor (35), driving force F for driving the workbench (24) to do linear motion is transmitted, and meanwhile the driving force F is measured.
  3. 3. The test device according to claim 1, characterized in that the screw nut is fixedly connected with the screw nut (36) through a screw, the force sensor (35) is fixedly connected with the screw nut and the force sensor connecting seat (37) through a force sensor connecting washer (34) and an inner hexagon screw (33), the workbench is fixedly connected with the force sensor connecting seat (25) through a bolt and the workbench (24), and the force sensor (35) is fixedly connected with the workbench and the force sensor connecting seat (25) through the force sensor connecting washer (34) and the inner hexagon screw (33).
  4. 4. The test device according to claim 1, wherein a left travel switch (23) and a right travel switch (26) are mounted on the servo slipway (16), brackets of the left travel switch (23) and the right travel switch (26) are fixedly connected with a servo slipway seat (27) through screws, and the workbench (24) reciprocates linearly between the left travel switch (23) and the right travel switch (26).
  5. 5. The test device according to claim 1, wherein the weight tray (10) comprises a tray (54), a connecting boom (55) and a tray lifting lug (56) welded in sequence.
  6. 6. Test device according to claim 1, characterized in that the lower tray lifting lug (52) of the turret (6) hangs the weight tray (10) by means of the pin screw (7) and the nut (8), the weight (9) is placed on the weight tray (10), and the positive pressure applied to the bearing seat test piece (13) by the turret (6) is adjusted by the weight of the placed weight (9).

Description

Test device for testing FAST reflecting surface unit 1# connecting mechanism Technical Field The invention relates to the technical field of radio astronomical telescopes, in particular to a test device for testing a 1# connecting mechanism of a FAST reflecting surface unit, and particularly relates to a test device for testing the friction coefficient and the abrasion life of the 1# connecting mechanism of the FAST reflecting surface unit. Background A500 m caliber spherical radio telescope (Five-handred-meter Aperture Spherical radio Telescope, FAST) is the global largest single caliber radio astronomical telescope, and has three independent innovations, namely, natural karst pits in Guizhou are used as table addresses, a reflecting surface is actively deformed, a flexible light mechanism dragged by six cables in parallel is adopted to drag a feed cabin to realize primary cable driving, and an AB rotating shaft mechanism and a Stewart parallel mechanism in the feed cabin realize secondary fine adjustment of the feed pose and realize high-precision positioning of the feed source. The FAST reflecting surface can realize instantaneous 300-meter caliber active deformation, a paraboloid is formed by spherical deformation, the paraboloid is ensured to always point to a celestial body to be observed, and radio wave signals from the celestial body are focused. At the same time, the feed receiver at the focal position receives and processes the radio wave signal, and the process is continuous. The FAST reflecting surface is composed of a peripheral supporting structure (ring beam lattice column), a cable net, a reflecting surface unit, a hydraulic actuator and the like. The ring beam is a space net frame ring beam structure with the inner diameter exceeding 500 meters, the width being about 11 meters and the height being about 5 meters, 50 lattice columns are used as supports of the ring beam, 150 lug plates are welded on ball nodes on the bottom surface of an inner ring of the ring beam, the lug plates are connected with 150 edge main ropes of a rope net, and the rope net structure supports and constrains 4450 reflecting surface units. Wherein triangular units 4300 are used and quadrilateral units 150 are used at the edge of the cable net. The reflecting surface unit is composed of a bolt net frame and an aluminum alloy panel, the bolt net frame is arranged at the lower part, the aluminum alloy panel is arranged at the upper part of the bolt net frame, and the bolt net frame and the aluminum alloy panel are connected together through a connecting piece in the middle. And the corner points of the upper chord members of the bolt net frame are fixedly connected with the node shaft ball nodes of the 1# connecting structure through bolts of the rod pieces. The corner points of each reflecting surface unit are different in connecting mechanisms, and the corner points are respectively provided with a 0# connecting mechanism, a 1# connecting mechanism and a 2# connecting mechanism. The 0# connecting mechanism and the 1# connecting mechanism comprise a bearing seat, a joint bearing and a large part of a node shaft 3, and the 2# connecting mechanism comprises a node shaft, a ball hinge seat, a ball hinge and a large part of a PTFE sliding block 4 fixedly connected on the ball pin. The 0# connecting mechanism restrains 3 translational degrees of freedom, the 1# connecting mechanism restrains 2 translational degrees of freedom, and the 2# connecting mechanism restrains 1 translational degree of freedom. The 3 sets (3 sets of triangle units) or 4 sets (4 sets of quadrilateral units) of each reflecting surface unit are arranged on the node disc of the cable net, the bearing seat of the 0# connecting mechanism and the 1# connecting mechanism are fixedly connected with the node disc supporting the same through bolts, and the PTFE sliding block of the 2# connecting mechanism can translate at will on the node disc supporting the same. Six degrees of freedom of the rigid reflecting surface unit are restrained by the restraining connection mode, so that the reflecting surface unit is connected with the cable net structure in a simple supporting restraining mode, and additional internal force cannot be caused by movement deformation of the cable net structure. A linear sliding bearing is formed between the node shaft of the 1# connecting mechanism and the inner ring of the joint bearing arranged in the bearing seat, when the FAST reflecting surface actively deforms, the relative positions of adjacent node discs can continuously change due to the active deformation of the cable net, and the linear sliding bearing can reciprocate along the axis of the node shaft so as to adapt to the change of the relative positions of the node discs of the cable net. In the long-term running process of the FAST, 3 kinds of connecting mechanisms of the reflecting surface unit sometimes have faults, including deformation and fracture of connecting bolts