An ultra-short mechanical fault self-recovery electromechanical servo mechanism

Abstract

The present application relates to a kind of ultra-short mechanical fault self-recovery electromechanical servo mechanism, using two sets of redundant, coaxial arrangement of screw drive components with same lead parameters and bearing capacity, jointly use a set of servo motor as power source, through screw rod limit roll electromagnetic clutch, nut limit roll electromagnetic clutch, when the main bearing screw pair occurs jam / jam fault, fault isolation processing can be carried out, while enabling standby bearing screw pair synchronous completion mechanical fault self-recovery, ensure that the performance of whole machine is not reduced, under the condition of miniaturization integration, the zero length is designed to be ultra-short, improve the power density of redundant EMA.

Description

Technical Field

[0001] This invention relates to an electromechanical actuator, and more particularly to an ultra-short-duration self-recovering electromechanical servo mechanism for mechanical faults, belonging to the field of mechanics. Background Technology

[0002] The core transmission unit of electromechanical servo mechanisms or electromechanical actuators (EMAs) often uses roller screws or ball screws. For ball screws, the motion of the balls on the helical raceway is uncertain, exhibiting both rolling and sliding states. From a meshing principle perspective, this can potentially lead to jamming or sticking. Furthermore, the ball screw's mechanical failures, due to a combination of factors including design flaws and manufacturing errors, are a major bottleneck affecting the reliability of EMAs. Roller screws primarily combine the planetary gear's rotational motion and the threaded axial meshing motion. While their motion state is more clearly defined, the threaded meshing on a curved surface cannot be perfectly solved theoretically. The multi-point contact of the thread, primarily involving sliding, makes roller screw failures frequent. Considering both transmission components, single-point failures in EMAs are difficult to eliminate, and it's not easy to improve their reliability directly. Therefore, proposing an EMA scheme with redundancy for screw mechanical transmission failures is particularly important. Summary of the Invention

[0003] The technical problem to be solved by this invention is: the ultra-short mechanical fault self-recovering electromechanical servo mechanism proposed in this invention adopts redundant design, redundancy design, and fault-tolerant design for the mechanical transmission components. After fault detection and identification, it can isolate and recover from the fault, ensuring that the overall performance is not reduced. With miniaturization and integration as the goal, the zero position length is designed to be ultra-short, which has a significant effect on ensuring the power density of the EMA.

[0004] The technical solution adopted in this invention is: an ultra-short-length self-recovering electromechanical servo mechanism for mechanical faults, comprising: a servo motor assembly, a main working roller screw assembly, a backup working roller screw assembly, a screw limiting electromagnetic clutch assembly, a nut limiting electromagnetic clutch assembly, and an external connection assembly.

[0005] External connection components include the housing, front cover bolts, and rear cover bolts;

[0006] The servo motor assembly includes a motor rotor, a motor stator, a motor inner housing, a motor front bearing housing, a motor front end cover, a main clutch connecting sprocket, and a backup clutch connecting sprocket; permanent magnets are attached to the surface of the motor rotor; the motor stator is installed in the motor inner housing and is coaxially mounted with the motor rotor; the motor front bearing housing is installed at one end of the motor inner housing.

[0007] The main working roller screw assembly includes an internally threaded end face toothed nut, a hollow long shaft screw, a first roller, and a first cage. The motor rotor is mounted on the internally threaded end face toothed nut, and both ends of the internally threaded end face toothed nut are mounted on bearing seats inside the motor housing and the front bearing seat of the motor via bearings. The two ends of the internally threaded end face toothed nut are respectively mounted on the main clutch connecting chuck and the backup clutch connecting chuck. The first roller is mounted on one end of the hollow long shaft screw, and the first roller is installed in the internally threaded end face toothed nut, forming the main working roller screw assembly. The first cage is respectively provided at the end of the first roller. The other end of the hollow long shaft screw extends out from the center hole of the main clutch connecting chuck.

[0008] The lead screw limiting electromagnetic clutch assembly is installed at the end of the hollow long shaft lead screw that extends from the center hole of the main clutch connecting chuck, located inside the motor front bearing housing, and mates with the main clutch connecting chuck; the motor front end cover is installed at the end of the motor front bearing housing and is fixed with front end cover bolts.

[0009] The inner housing of the motor and the front bearing housing of the motor are installed inside the outer casing, with the front bearing housing of the motor located at the opening end of the outer casing.

[0010] The standby working roller screw assembly includes an internally threaded splined short nut, a solid long-shaft screw, a second roller, and a second cage. One end of the solid long-shaft screw is fixedly connected to the inner end face of the housing seal end by a rear end cap bolt, restricting the rotation of the solid long-shaft screw and allowing relative movement of the solid long-shaft screw along the axial direction. The other end of the solid long-shaft screw is inserted into the center hole of the hollow long-shaft screw. The second roller is mounted on the solid long-shaft screw, located outside the standby clutch connecting gear, and an internally threaded splined short nut is installed on the outer ring of the second roller, forming the standby working roller screw assembly. A second cage is provided at the end of the second roller.

[0011] The nut-limiting electromagnetic clutch assembly is mounted on a short nut with internal thread spline teeth and mates with the backup clutch connecting gear.

[0012] Furthermore, the lead screw limiting electromagnetic clutch assembly includes a limiting spline sleeve, a first movable double-sided spline gear, a first electromagnetic attraction coil, a first return spring, a first fixed end face gear, and a first bearing fixing seat;

[0013] The limiting knurled sleeve is installed at the end of the hollow long shaft lead screw extending from the center hole of the main clutch connecting gear. The center hole of the limiting knurled sleeve is a waist hole. Two longitudinally symmetrical cross-sections are arranged on the hollow long shaft lead screw, which mate with the center hole of the limiting knurled sleeve. The first movable double-sided splined gear and the limiting knurled sleeve are fitted with an inner spline hole and an outer splined shaft, transmitting rotational motion and reciprocating along the axial direction of the hollow long shaft lead screw. The first bearing fixing seat is installed on the limiting knurled sleeve through a deep groove ball bearing, relative to the limiting knurled sleeve. The splined sleeve rotates, the first fixed end face toothed plate is fitted outside the first bearing mounting seat, the first return spring is compressed in the corresponding hole between the first movable double-sided spline toothed plate and one side of the first fixed end face toothed plate, and the first movable double-sided spline toothed plate is reset and disengaged; the flange end face of the first bearing mounting seat and the first fixed end face toothed plate are fixed together on the inner wall of the front bearing seat of the motor; the first electromagnetic attraction coil is installed in the grooved ring on the other side of the first fixed end face toothed plate, and the first movable double-sided spline toothed plate is electromagnetically attracted.

[0014] Furthermore, the lead screw limiting electromagnetic clutch assembly switches between clutch and engagement by controlling the rotational motion of the main working roller lead screw pair by energizing or de-energizing the first electromagnetic engagement coil.

[0015] When the first electromagnetic engagement coil is de-energized, the first movable double-sided splined gearbox engages with the main clutch connecting gearbox and disengages from the first fixed end face gearbox. The first movable double-sided splined gearbox drives the limiting roll spline rotating sleeve to rotate together through the inner and outer spline connection. The limiting roll spline rotating sleeve drives the hollow long shaft lead screw to rotate together, so that the main working roller screw assembly cannot output linear motion.

[0016] When the first electromagnetic engagement coil is energized, the first movable double-sided splined toothed sprocket disengages from the main clutch toothed sprocket and engages with the first fixed end face toothed sprocket. The knurled sleeve remains fixed to the first fixed end face toothed sprocket, and the knurled sleeve constrains the hollow long shaft lead screw to move axially, causing the main working roller screw assembly to output linear motion.

[0017] Furthermore, the nut-limiting electromagnetic clutch assembly includes a second movable double-sided splined toothed sprocket, a second electromagnetic attraction coil, a second return spring, a second fixed end face toothed sprocket, and a second bearing mounting seat;

[0018] The second movable double-sided splined gear and the internally threaded splined short nut are fitted with an internal splined hole and an external splined shaft to transmit rotational motion, and both can reciprocate axially. The second bearing mounting seat is mounted on the internally threaded splined short nut via an angular contact ball bearing and rotates relative to the internally threaded splined short nut. The second fixed end face gear is fitted onto the second bearing mounting seat, and the second return spring is compressed in the corresponding hole between the second movable double-sided splined gear and the second fixed end face gear, performing a reset and disengagement action on the second movable double-sided splined gear. The flange end faces of the second bearing mounting seat and the second fixed end face gear are jointly fixed to the inner wall of the motor housing. The second electromagnetic attraction coil is installed in the grooved ring on the other side of the second fixed end face gear, performing electromagnetic attraction on the second movable double-sided splined gear.

[0019] Furthermore, the nut-limiting electromagnetic clutch assembly switches between clutch and engagement by controlling the rotational motion of the working roller screw assembly through energizing or de-energizing the second electromagnetic engagement coil.

[0020] When the second electromagnetic attraction coil is de-energized, the second movable double-sided splined toothed plate engages with the backup clutch connecting toothed plate and simultaneously disengages from the second fixed end face toothed plate. The second movable double-sided splined toothed plate uses the inner and outer splines to drive the short nut of the internal thread spline teeth to rotate together, so that the solid long shaft lead screw outputs reciprocating linear motion.

[0021] When the second electromagnetic engagement coil is energized, the second movable double-sided splined toothed sprocket disengages from the backup clutch toothed sprocket and engages with the second fixed end face toothed sprocket. The power of the servo motor assembly cannot be transmitted to the backup working roller screw assembly. The internal thread spline tooth short nut, the solid long shaft screw, and the second roller thread only bear static loads and do not move.

[0022] Furthermore, in the lead screw limiting electromagnetic clutch assembly and the nut limiting electromagnetic clutch assembly, the first electromagnetic engagement coil and the second electromagnetic engagement coil are simultaneously powered to ensure that the first moving double-sided splined sprocket and the second moving double-sided splined sprocket simultaneously engage / disengage the main clutch connecting sprocket and the backup clutch connecting sprocket, thereby realizing the handling and self-recovery of mechanical faults such as lead screw jamming / sticking.

[0023] Furthermore, the inner cavity of the outer shell is a cuboid structure, and the inner housing of the motor is also cuboid. The outer shell and the inner housing of the motor cooperate with each other to restrict the rotation of the servo motor.

[0024] Furthermore, the external connection assembly also includes a front end support and a load-bearing steel ball; the load-bearing steel ball is installed between the hollow long shaft screw and the front end support and rotates in a circular motion. When the main working roller screw assembly outputs linear motion, the hollow long shaft screw and the front end support do not rotate relative to each other and can only reciprocate along the axis; when the backup working roller screw assembly outputs linear motion, the hollow long shaft screw and the front end support rotate relative to each other and reciprocate along the axis.

[0025] Furthermore, the reciprocating linear stroke of the main working roller screw assembly is 2x, and the reciprocating linear stroke of the standby working roller screw assembly is 4x.

[0026] Furthermore, the lead screw limiting electromagnetic clutch assembly, the nut limiting electromagnetic clutch assembly, and the standby working roller screw pair assembly do not work in non-fault mode. In normal operation, the first electromagnetic attraction coil and the second electromagnetic attraction coil are energized simultaneously. The servo motor assembly drives the toothed nut on the internal thread end face of the main working roller screw pair assembly to rotate and output power. Under the constraint of the lead screw limiting electromagnetic clutch assembly, the hollow long shaft lead screw cannot rotate and can only move axially back and forth. The standby working roller screw pair assembly has no power input.

[0027] When a mechanical transmission failure occurs in the main working roller screw assembly, it enters a fault self-recovery mode. The first and second electromagnetic engagement coils are simultaneously de-energized, and the screw-limiting electromagnetic clutch assembly and the nut-limiting electromagnetic clutch assembly are simultaneously activated. This causes the motor rotor to drive the hollow long-shaft screw and the internally threaded spline short nut to rotate together. The main working roller screw assembly becomes a static load-bearing connection, and the backup working roller screw assembly converts rotation into linear output to the external connection assembly, thus completing the mechanical fault self-recovery.

[0028] The advantages of this invention compared to the prior art are:

[0029] (1) The ultra-short mechanical fault self-recovery electromechanical servo mechanism proposed in this invention realizes the redundant design, redundancy design and fault-tolerant design of mechanical transmission components. After fault detection and identification, it can perform fault isolation and recovery work.

[0030] (2) The ultra-short mechanical fault self-recovery electromechanical servo mechanism proposed in this invention achieves miniaturization and integration without reducing the overall performance. The zero position length is designed to be ultra-short, which has a significant effect on ensuring the power density of the EMA.

[0031] (3) The ultra-short mechanical fault self-recovery electromechanical servo mechanism proposed in this invention has a customized design of a double-sided toothed electromagnetic clutch. It has a compact structure, small size and can transmit greater torque. The electromagnetic clutch can quickly switch faults and is suitable for EMA redundancy design schemes.

[0032] (4) The ultra-short mechanical fault self-recovery electromechanical servo mechanism proposed in this invention can be extended to the field of high reliability and high safety actuation technology, and has a broader application prospect. Attached Figure Description

[0033] Figure 1This is a diagram showing the internal structure of the ultra-short-duration self-recovering electromechanical servo mechanism provided in this embodiment of the invention.

[0034] Figure 2 This is a schematic diagram of the appearance of the ultra-short-duration self-recovering electromechanical servo mechanism for mechanical faults provided in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the moving double-sided splined toothed plate of the ultra-short mechanical fault self-recovery electromechanical servo mechanism provided in the embodiment of the present invention. Detailed Implementation

[0036] The present invention will be described in conjunction with the accompanying drawings.

[0037] like Figure 1 As shown, an ultra-short-range self-recovering electromechanical servo mechanism for mechanical faults includes: a servo motor assembly, a main working roller screw assembly, a backup working roller screw assembly, a screw limiting electromagnetic clutch assembly, a nut limiting electromagnetic clutch assembly, and an external connection assembly.

[0038] The external connection components include a front end lug 6a, a housing 6b, a load-bearing steel ball 6c, a front end cover bolt 6d, and a rear end cover bolt 6e.

[0039] The servo motor assembly includes a motor rotor 1a, a motor stator 1b, a motor inner housing 1c, a motor front bearing housing 1d, a motor front end cover 1e, a main clutch connecting sprocket 1f, and a backup clutch connecting sprocket 1g.

[0040] The surface of the motor rotor 1a of the servo motor assembly is covered with a permanent magnet. The motor stator 1b is arranged coaxially with the motor rotor 1a and is installed inside the motor housing 1c by an interference fit. The motor front bearing seat 1d is installed at one end of the motor housing 1c. The motor housing 1c and the motor front bearing seat 1d are installed inside the outer shell 6b, and the motor front bearing seat 1d is located at the open end of the outer shell 6b.

[0041] The main working roller screw assembly includes an internally threaded end-face toothed nut, a hollow long-shaft screw 2b, a first roller 2c, and a first cage 2d. The motor rotor 1a is mounted on the internally threaded end-face toothed nut 2a. Both ends of the internally threaded end-face toothed nut 2a are mounted on bearing seats inside the motor housing 1c and on the front bearing seat 1d of the motor via bearings. The main clutch connecting chuck 1f and the backup clutch connecting chuck 1g are respectively mounted on the two ends of the internally threaded end-face toothed nut 2a. One end of the hollow long-shaft screw 2b is equipped with the first roller 2c, which is installed within the internally threaded end-face toothed nut 2a, forming the main working roller screw assembly. The first cage 2d is provided at the end of the first roller 2c. The other end of the hollow long-shaft screw 2b extends from the center hole of the main clutch connecting chuck 1f.

[0042] The internally threaded end-face toothed nut 2a, the first roller 2c, the first cage 2d, and the hollow long-shaft lead screw 2b are arranged coaxially from the outside to the inside, forming the main working roller screw pair through the thread meshing principle. The internally threaded end-face toothed nut 2a is driven by the servo motor assembly to rotate. When the hollow long-shaft lead screw 2b is restricted to axial movement, several first rollers 2c rotate cyclically under the constraint of the first cage 2d, thereby converting the servo motor rotation into linear output.

[0043] The spare working roller screw assembly includes an internally threaded splined short nut 3a, a solid long-shaft screw 3b, a second roller 3c, and a second cage 3d. One end of the solid long-shaft screw 3b is fixedly connected to the inner end face of the sealed end of the outer casing 6b by a rear end cap bolt 6e, restricting the rotation of the solid long-shaft screw 3b and allowing relative movement of the solid long-shaft screw 3b along the axial direction. The other end of the solid long-shaft screw 3b is inserted into the center hole of the hollow long-shaft screw 2b. The second roller 3c is mounted on the solid long-shaft screw 3b, located outside the spare clutch connecting chuck 1g. The outer ring of the second roller 3c is fitted with an internally threaded splined short nut 3a, forming the spare working roller screw assembly. The second cage 3d is provided at the end of the second roller 3c.

[0044] The internally threaded splined short nut 3a, the second roller 3c, the second cage 3d, and the solid long-shaft lead screw 3b are arranged coaxially from the outside to the inside, forming a working roller-lead screw pair through the threaded meshing principle. When the internally threaded splined short nut 3a is driven to rotate by the servo motor assembly, the second roller 3c and the second cage 3d rotate cyclically, forcing the solid long-shaft lead screw 3b to convert the servo motor rotation into linear output.

[0045] The lead screw limiting electromagnetic clutch assembly includes a limiting spline sleeve 4a, a first movable double-sided splined sprocket 4b, a first electromagnetic engagement coil 4c, a first return spring 4d, a first fixed end face sprocket 4e, and a first bearing mounting seat 4f. The limiting spline sleeve 4a is installed at one end of the hollow long-shaft lead screw 2b extending from the center hole of the main clutch connecting sprocket 1f. The center hole of the limiting spline sleeve 4a is a slotted hole. Two longitudinally symmetrical cross-sections are arranged on the hollow long-shaft lead screw 2b, which mate with the center hole of the limiting spline sleeve 4a. The first movable double-sided splined sprocket 4b and the limiting spline sleeve 4a are fitted with an inner spline hole and an outer splined shaft, transmitting rotational motion, and both reciprocate along the axial direction of the hollow long-shaft lead screw 2b. The first electromagnetic engagement coil 4c is installed in a grooved ring on the other side of the first fixed end face sprocket 4e via an interference fit, enabling it to control the first movable... The double-sided splined toothed sprocket 4b performs an electromagnetic attraction action; the first return spring 4d is located in the middle position between the first movable double-sided splined toothed sprocket 4b and the first fixed end face toothed sprocket 4e, and the spring is compressed in the corresponding holes of the two parts, which can perform a reset and disengagement action on the first movable double-sided splined toothed sprocket 4b; the first fixed end face toothed sprocket 4e is sleeved outside the first bearing fixing seat 4f, and a pair of deep groove ball bearings are installed on the inner side of the first bearing fixing seat 4f, which rotate relative to the limiting knurled spline sleeve 4a; the flange end faces of the first bearing fixing seat 4f and the first fixed end face toothed sprocket 4e are jointly fixed to the inner wall of the motor front bearing seat 1d by the countersunk screw assembly;

[0046] The lead screw limiting electromagnetic clutch assembly is a hollow structure and is installed on the motion / power output side of the main working roller screw assembly. It switches between clutch engagement and disengagement by controlling the rotation of the main working roller screw assembly through energizing / de-energizing the first electromagnetic engagement coil 4c. The first movable double-sided splined sprocket 4b is located coaxially between the main clutch connecting sprocket 1f and the first fixed end face sprocket 4e. When the first electromagnetic engagement coil 4c is de-energized, the first movable double-sided splined sprocket 4b engages with the smaller diameter sprocket of the main clutch connecting sprocket 1f, while simultaneously disengaging from the larger diameter sprocket of the first fixed end face sprocket 4e. The internal and external spline connections drive the clutch. The knurled sleeve 4a rotates together with the hollow long shaft screw 2b via the flat shaft / flat hole connection, thus preventing the main working roller screw assembly from outputting linear motion. When the first electromagnetic engagement coil 4c is energized, the first moving double-sided splined toothed plate 4b disengages from the smaller diameter toothed plate of the main clutch connecting toothed plate 1f, while simultaneously engaging with the larger diameter toothed plate of the first fixed end face toothed plate 4e. The knurled sleeve 4a and the first fixed end face toothed plate 4e remain fixed, and the hollow long shaft screw 2b is constrained to move only axially via the flat shaft / flat hole connection, thus enabling the main working roller screw assembly to output linear motion.

[0047] The nut-limiting electromagnetic clutch assembly includes a second movable double-sided splined sprocket 5a, a second electromagnetic engagement coil 5b, a second return spring 5c, a second fixed end face sprocket 5d, and a second bearing mounting seat 5e. The second movable double-sided splined toothed sprocket 5a and the internally threaded splined toothed short nut 3a are fitted with an internal splined hole and an external splined shaft, which can transmit rotational motion and the two can move axially back and forth; the second electromagnetic attraction coil 5b is installed in the grooved ring on the other side of the second fixed end face toothed sprocket 5d through an interference fit, which can perform electromagnetic attraction action on the second movable double-sided splined toothed sprocket 5a; the second return spring 5c ​​is located in the middle position of the second movable double-sided splined toothed sprocket 5a and the second fixed end face toothed sprocket 5d, and the spring is compressed in the corresponding holes of the two parts, which can perform a reset and disengagement action on the second movable double-sided splined toothed sprocket 5a; the second fixed end face toothed sprocket 5d is fitted on the second bearing fixing seat 5e, and a pair of angular contact ball bearings are installed on the inner side of the second bearing fixing seat 5e, which rotate relative to the internally threaded splined toothed short nut 3a; the flange end faces of the second bearing fixing seat 5e and the second fixed end face toothed sprocket 5d are jointly fixed to the inner wall of the motor inner housing 1c by a countersunk screw assembly;

[0048] The nut-limiting electromagnetic clutch assembly is a hollow structure and is installed on the right side of the standby working roller screw assembly. The clutch engagement / disengagement is switched by controlling the rotation of the standby working roller screw assembly by energizing / de-energizing the second electromagnetic engagement coil 5b. The second movable double-sided splined sprocket 5a is located coaxially between the backup clutch connecting sprocket 1g and the second fixed end face sprocket 5d. When the second electromagnetic engagement coil 5b is de-energized, the second movable double-sided splined sprocket 5a engages with the smaller diameter sprocket of the backup clutch connecting sprocket 1g, while simultaneously disengaging from the larger diameter sprocket of the second fixed end face sprocket 5d. The internal and external spline connections drive the internally threaded splined short nut 3a to rotate together, thereby causing the solid long shaft screw 3b of the backup working roller screw assembly to output reciprocating linear motion. When the second electromagnetic engagement coil 5b is energized, the second movable double-sided splined sprocket 5a disengages from the smaller diameter sprocket of the backup clutch connecting sprocket 1g, while simultaneously engaging with the larger diameter sprocket of the second fixed end face sprocket 5d. The power of the servo motor assembly cannot be transmitted to the backup working roller screw assembly, and the internally threaded splined short nut 3a, the solid long shaft screw 3b, and the second roller 3c can only statically bear loads without any movement.

[0049] The first return spring 4d and the second return spring 5c ​​are respectively installed inside the corresponding seat holes of the first fixed end face toothed plate 4e and the second fixed end face toothed plate 5d, and can attract and reset the first movable double-sided spline toothed plate 4b and the second movable double-sided spline toothed plate 5a.

[0050] A load-bearing steel ball 6c is installed between the hollow long shaft lead screw 2b and the front end support 6a and rotates in a circular motion. When the main working roller screw assembly is working normally, the hollow long shaft lead screw 2b and the front end support 6a do not rotate relative to each other and can only reciprocate along the axis. When the standby working roller screw assembly is working, the hollow long shaft lead screw 2b and the front end support 6a rotate relative to each other and reciprocate along the axis.

[0051] The outer casing 6b and the solid long shaft lead screw 3b are fixedly connected by the rear end cover bolt 6e flange, so that the solid long shaft lead screw 3b cannot rotate and can only move along the axis of the mechanism.

[0052] The ultra-short-length self-recovering electromechanical servo mechanism has a square overall structure with semi-circular connecting lugs installed at the front and rear. The actuating rod can extend from its square central hole, enabling reciprocating telescopic movement.

[0053] like Figure 2 As shown, the inner cavity of the outer shell 6b has a square structure, and the outer shape of the inner housing 1c of the motor has a square structure. The four square surfaces of the two cooperate with each other to restrict the rotation of the servo motor.

[0054] The spare working roller screw assembly, the nut rolling limit electromagnetic clutch assembly, the servo motor assembly, the main working roller screw assembly, the screw rolling limit electromagnetic clutch assembly, and the external connection assembly are sequentially installed on the same axis from left to right. The two clutches are arranged on both sides of the motor assembly shaft. The linear motion parts of the two screw assemblies are interlocked and do not interfere with each other. The two clutches and the spare working roller screw assembly do not work in non-fault mode.

[0055] During normal operation, the servo motor assembly drives the nut of the main working roller screw assembly to rotate and output power. Under the constraint of the screw rolling limit electromagnetic clutch assembly, the screw cannot rotate and can only move axially back and forth. The cold backup roller screw assembly has no power input, and the screw thread acts as a static load-bearing connection. When the electromechanical system detects a mechanical transmission fault such as thread jamming / sticking in the main working roller screw assembly, it switches to the fault self-recovery mode. The screw rolling limit electromagnetic clutch assembly and the nut rolling limit electromagnetic clutch assembly are activated simultaneously, and the end face teeth disengage and then re-engage. This causes the motor rotor 1a to drive the hollow long shaft screw 2b and the internal thread spline short nut 3a to rotate together. The main working roller screw assembly becomes a static load-bearing connection, and the backup working roller screw assembly realizes the rotational conversion to linear output to the external connection assembly, completing the mechanical fault self-recovery.

[0056] The lead screw limiting electromagnetic clutch assembly and the nut limiting electromagnetic clutch assembly need to be powered synchronously by the first electromagnetic engagement coil 4c and the second electromagnetic engagement coil 5b to ensure that they engage / disengage synchronously with the main clutch connecting sprocket 1f and the backup clutch connecting sprocket 1g. Only when both sprockets are successfully and accurately controlled at the same time can the mechanical fault handling and self-recovery of the lead screw jamming / stuck be achieved.

[0057] The pair of support bearings of the servo motor assembly and the pair of support bearings of the spare working roller screw assembly can both bear the same axial force and have the same upper speed limit requirement. The pair of support bearings of the screw limiting electromagnetic clutch assembly cannot bear axial force, but the upper speed limit requirement is the same as the former two.

[0058] The main working roller screw assembly and the backup working roller screw assembly have the same lead parameters, and both can bear the same axial force and have the same upper speed limit requirements.

[0059] like Figure 3 As shown, the inner wall of the center hole of the first movable double-sided splined toothed disc 4b and the second movable double-sided splined toothed disc 5a is provided with splines, and a ring of teeth is provided on each side of the disc, with different diameters of the tooth rings on the two sides.

[0060] The screw-limiting electromagnetic clutch assembly and the nut-limiting electromagnetic clutch assembly have the same structural design parameters and load-bearing capacity for both the smaller and larger diameter cranks.

[0061] The reciprocating linear stroke of the main working roller screw assembly is 2x, and the reciprocating linear stroke of the backup working roller screw assembly is 4x, which is a 2x design relationship.

[0062] The parts of this invention not described in detail are well-known to those skilled in the art.

Claims

1. An ultra-short mechanical fault self-recovery electromechanical actuator, characterized in that, include: Servo motor assembly, main working roller screw assembly, spare working roller screw assembly, screw rolling limiting electromagnetic clutch assembly, nut rolling limiting electromagnetic clutch assembly, and external connection assembly. The servo motor assembly is coaxially mounted with the main working roller screw assembly; one end of the lead screw of the backup working roller screw assembly is fixed internally to the external connecting assembly, and the other end is connected to the lead screw of the main working roller screw assembly; the lead screw limiting electromagnetic clutch assembly is located at the power output end of the main working roller screw assembly, and the nut limiting electromagnetic clutch assembly is located on the backup working roller screw assembly. The lead screw limiting electromagnetic clutch assembly, the nut limiting electromagnetic clutch assembly, and the standby working roller screw pair assembly do not work in non-fault mode. In normal operation, the servo motor assembly drives the main working roller screw pair assembly to output power. Under the constraint of the lead screw limiting electromagnetic clutch assembly, the main working roller screw pair assembly outputs axial reciprocating movement, while the standby working roller screw pair assembly has no power input. When a mechanical transmission failure occurs in the main working roller screw assembly, it enters the fault self-recovery mode. The screw limiting electromagnetic clutch assembly and the nut limiting electromagnetic clutch assembly are activated simultaneously, causing the servo motor assembly to drive the main working roller screw assembly and the backup working roller screw assembly to rotate together. The main working roller screw assembly becomes a static load-bearing connection, and the backup working roller screw assembly realizes the conversion of rotation into linear output to the external connection assembly, thus completing the mechanical fault self-recovery. The lead screw limiting electromagnetic clutch assembly includes a limiting spline sleeve (4a), a first movable double-sided spline gear plate (4b), a first electromagnetic attraction coil (4c), a first return spring (4d), a first fixed end face gear plate (4e), and a first bearing fixing seat (4f). The limiting knurled sleeve (4a) is installed on one end of the hollow long shaft screw (2b) extending from the center hole of the main clutch connecting chuck (1f). The center hole of the limiting knurled sleeve (4a) is a waist hole. Two longitudinally oriented cut surfaces are symmetrically arranged on the hollow long shaft screw (2b) to mate with the center hole of the limiting knurled sleeve (4a). The first movable double-sided splined chuck (4b) and the limiting knurled sleeve (4a) are fitted with an inner splined hole and an outer splined shaft to transmit rotational motion, and both reciprocate along the axial direction of the hollow long shaft screw (2b). The first bearing fixing seat (4f) is installed on the limiting knurled sleeve (4a) through a deep groove ball bearing, relative to the limiting knurled sleeve. (4a) Rotation: The first fixed end face toothed plate (4e) is fitted outside the first bearing fixing seat (4f). The first return spring (4d) is compressed in the corresponding hole between the first movable double-sided spline toothed plate (4b) and the first fixed end face toothed plate (4e) on one side, and performs a reset and disengagement action on the first movable double-sided spline toothed plate (4b). The flange end faces of the first bearing fixing seat (4f) and the first fixed end face toothed plate (4e) are fixed together on the inner wall of the front bearing seat (1d) of the motor. The first electromagnetic attraction coil (4c) is installed in the grooved ring on the other side of the first fixed end face toothed plate (4e) and performs electromagnetic attraction on the first movable double-sided spline toothed plate (4b). The lead screw limiting electromagnetic clutch assembly switches between engagement and disengagement by controlling the rotation of the main working roller lead screw pair by energizing or de-energizing the first electromagnetic attraction coil (4c). When the first electromagnetic engagement coil (4c) is de-energized, the first movable double-sided splined gear plate (4b) engages with the main clutch connecting gear plate (1f) and disengages from the first fixed end face gear plate (4e). The first movable double-sided splined gear plate (4b) drives the limiting knurled sleeve (4a) to rotate together through the inner and outer spline connection. The limiting knurled sleeve (4a) drives the hollow long shaft screw (2b) to rotate together, so that the main working roller screw assembly cannot output linear motion. When the first electromagnetic attraction coil (4c) is energized, the first movable double-sided splined toothed plate (4b) disengages from the main clutch connecting toothed plate (1f) and engages with the first fixed end face toothed plate (4e). The knurled sleeve (4a) remains fixed to the first fixed end face toothed plate (4e). The knurled sleeve (4a) constrains the hollow long shaft lead screw (2b) to move axially, so that the main working roller lead screw assembly outputs linear motion. The nut-limiting electromagnetic clutch assembly includes a second movable double-sided splined sprocket (5a), a second electromagnetic attraction coil (5b), a second return spring (5c), a second fixed end face sprocket (5d), and a second bearing mounting seat (5e). The second movable double-sided splined gear sprocket (5a) and the internally threaded splined short nut (3a) are fitted with an internal splined hole and an external splined shaft to transmit rotational motion, and both can reciprocate axially; the second bearing mounting seat (5e) is mounted on the internally threaded splined short nut (3a) via an angular contact ball bearing and rotates relative to the internally threaded splined short nut (3a); the second fixed end face gear sprocket (5d) is fitted on the second bearing mounting seat (5e), ​​and the second return spring (5c) is compressed on the second movable double-sided splined gear sprocket. The second movable double-sided splined toothed plate (5a) is reset and disengaged in the corresponding hole between the two fixed end face toothed plates (5d) on one side; the second bearing fixing seat (5e) and the flange end face of the second fixed end face toothed plate (5d) are fixed together on the inner wall of the motor inner housing (1c); the second electromagnetic attraction coil (5b) is installed in the grooved ring on the other side of the second fixed end face toothed plate (5d) to electromagnetically attract the second movable double-sided splined toothed plate (5a); The nut limiting electromagnetic clutch assembly switches between engagement and disengagement by controlling the rotational motion of the working roller screw assembly through energizing or de-energizing the second electromagnetic attraction coil (5b). When the second electromagnetic attraction coil (5b) is de-energized, the second movable double-sided splined toothed plate (5a) engages with the backup clutch connecting toothed plate (1g) and simultaneously disengages from the second fixed end face toothed plate (5d). The second movable double-sided splined toothed plate (5a) uses the inner and outer splines to drive the short nut (3a) of the internal thread spline teeth to rotate together, so that the solid long shaft lead screw (3b) outputs reciprocating linear motion. When the second electromagnetic attraction coil (5b) is energized, the second movable double-sided splined toothed plate (5a) disengages from the backup clutch connecting toothed plate (1g) and engages with the second fixed end face toothed plate (5d). The power of the servo motor assembly cannot be transmitted to the backup working roller screw assembly. The internal thread spline tooth short nut (3a), solid long shaft screw (3b), and second roller (3c) threads only bear static loads and do not move. In the aforementioned lead screw limiting electromagnetic clutch assembly and nut limiting electromagnetic clutch assembly, the first electromagnetic engagement coil (4c) and the second electromagnetic engagement coil (5b) are simultaneously powered to ensure that the first movable double-sided splined sprocket (4b) and the second movable double-sided splined sprocket (5a) simultaneously engage / disengage the main clutch connecting sprocket (1f) and the backup clutch connecting sprocket (1g), thereby realizing the handling and self-recovery of mechanical faults such as lead screw jamming / stuck.

2. An ultra-short mechanical fault self-recovery electromechanical servo mechanism according to claim 1, characterized in that, The servo motor assembly includes a motor rotor (1a), a motor stator (1b), a motor inner housing (1c), a motor front bearing housing (1d), and a motor front end cover (1e); a permanent magnet is attached to the surface of the motor rotor (1a); the motor stator (1b) is installed in the motor inner housing (1c) and is coaxially mounted with the motor rotor (1a); the motor front bearing housing (1d) is installed at one end of the motor inner housing (1c).

3. An ultra-short mechanical fault self-recovery electromechanical servo mechanism according to claim 2, characterized in that, The servo motor assembly also includes a main clutch connecting sprocket (1f) and a backup clutch connecting sprocket (1g); the main working roller screw assembly includes an internally threaded end face toothed nut (2a), a hollow long shaft screw (2b), a first roller (2c), and a first cage (2d); the motor rotor (1a) is mounted on the internally threaded end face toothed nut (2a), and the two ends of the internally threaded end face toothed nut (2a) are mounted on bearing seats inside the motor housing (1c) and the front bearing seat (1d) of the motor via bearings. On the ) ; the two ends of the internal thread end face toothed nut (2a) are respectively installed with the main clutch connecting toothed sprocket (1f) and the backup clutch connecting toothed sprocket (1g); the hollow long shaft screw (2b) is equipped with a first roller (2c) at one end, the first roller (2c) is installed in the internal thread end face toothed nut (2a) to form the main working roller screw pair, the first retainer (2d) is respectively set at the end of the first roller (2c), and the other end of the hollow long shaft screw (2b) extends out from the center hole of the main clutch connecting toothed sprocket (1f).

4. An ultra-short mechanical fault self-recovery electromechanical servo mechanism according to claim 3, characterized in that, The external connection assembly includes a housing (6b) and a front cover bolt (6d); the lead screw limiting electromagnetic clutch assembly is installed at one end of the hollow long shaft lead screw (2b) extending from the center hole of the main clutch connecting chuck (1f), located inside the motor front bearing housing (1d), and mates with the main clutch connecting chuck (1f); the motor front cover (1e) is installed at the end of the motor front bearing housing (1d) and fixed with the front cover bolt (6d); The inner housing of the motor (1c) and the front bearing housing of the motor (1d) are installed inside the outer casing (6b), with the front bearing housing of the motor (1d) located at the open end of the outer casing (6b).

5. An ultra-short mechanical fault self-recovery electromechanical servo mechanism according to claim 4, characterized in that, The external connection assembly also includes a rear end cap bolt (6e); the backup working roller screw assembly includes an internally threaded spline short nut (3a), a solid long shaft screw (3b), a second roller (3c), and a second cage (3d); one end of the solid long shaft screw (3b) is fixedly connected to the inner end face of the sealing end of the outer shell (6b) through the rear end cap bolt (6e), restricting the rotation of the solid long shaft screw (3b) and allowing the solid long shaft screw (3b) to move relative to each other along the axial direction, and the other end of the solid long shaft screw (3b) is inserted into the center hole of the hollow long shaft screw (2b); the second roller (3c) is mounted on the solid long shaft screw (3b) and located outside the backup clutch connecting toothed disc (1g), and the outer ring of the second roller (3c) is fitted with an internally threaded spline short nut (3a), forming a backup working roller screw assembly; the end of the second roller (3c) is provided with a second cage (3d). The nut-limiting electromagnetic clutch assembly is mounted on the internally threaded spline short nut (3a) and mates with the backup clutch connecting gear (1g).

6. An ultra-short mechanical fault self-recovery electromechanical servo mechanism according to claim 4, characterized in that, The inner cavity of the outer shell (6b) is a cuboid structure, and the inner housing of the motor (1c) is also cuboid. The outer shell (6b) and the inner housing of the motor (1c) cooperate with each other to restrict the rotation of the servo motor.

7. An ultra-short mechanical fault self-recovery electromechanical servo mechanism according to claim 4, characterized in that, The external connection assembly also includes a front end lug (6a) and a bearing steel ball (6c); the bearing steel ball (6c) is installed between the hollow long shaft screw (2b) and the front end lug (6a) and rotates in a cycle. When the main working roller screw assembly outputs linear motion, the hollow long shaft screw (2b) and the front end lug (6a) do not rotate relative to each other and can only reciprocate along the axis. When the backup working roller screw assembly outputs linear motion, the hollow long shaft screw (2b) and the front end lug (6a) rotate relative to each other and reciprocate along the axis.

8. An ultra-short mechanical fault self-recovery electromechanical servo mechanism according to claim 1, characterized in that, The reciprocating linear stroke of the main working roller screw assembly is 2x, and the reciprocating linear stroke of the backup working roller screw assembly is 4x.

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