External hexagonal parts screwing device and screwing method

Abstract

This invention discloses a screwing device and method for external hexagonal parts, targeting the field of on-orbit servicing for spacecraft. The screwing and clamping device includes: a circular outer shell limiting plate, three clamping rods, and three driven rods; the power transmission and control device includes: an active gear plate, a return spring, a cooperating chuck, and a limiting base. The screwing method includes: Step 1: The circular outer shell limiting plate contacts the object to be screwed. After confirmation, a rotary motor drives the active gear plate to rotate, and the three sets of clamping rods gradually approach the object to be screwed. Step 2: After the three sets of clamping rods clamp the object to be screwed, the rotary motor stops, and the cooperating chuck engages with the teeth of the active gear plate under the action of an electromagnet, locking the clamping rod positions. Step 3: The locking constraint between the screwing end tool and the end of the robotic arm is released, the rotary motor starts, driving the entire screwing device to rotate until the screwed part is finished.

Description

Technical Field

[0001] This invention pertains to the field of on-orbit services for spacecraft, specifically a screwing device and method for external hexagonal parts. Background Technology

[0002] In existing technologies, astronauts face significant risks when using manual tools for extravehicular activity (EVA) maintenance. Developing end-effector tools for spacecraft to perform on-orbit maintenance and upgrades can extend the lifespan of spacecraft and reduce the costs and risks associated with EVA during on-orbit operations.

[0003] For threaded connectors with hexagonal heads (such as bolts) and non-cylindrical heads, the commonly used tools currently employ a solution of equipping different models of connectors with corresponding wrenches and sockets. While this solution is convenient on the ground, it complicates the mission process and increases transportation costs when applied to space on-orbit services. Summary of the Invention

[0004] This invention addresses the problems existing in the prior art by disclosing a screwing device and method for external hexagonal threaded parts. The device is a controllable and adaptive screwing device for external hexagonal threaded connectors with adjustable operating diameter and high stability. By adjusting the shape of the screwing device, different types of external hexagonal threaded connectors can be screwed and disassembled.

[0005] This invention is implemented as follows:

[0006] A screwing device for external hexagonal parts, characterized in that the device includes a screwing clamping device and a power transmission and control device that are movably connected;

[0007] The aforementioned screwing and clamping device includes: a circular outer shell limiting plate (1), three clamping rods (2), and three driven rods (3); three cylindrical protruding shafts are evenly distributed around the outer circumference of the circular outer shell limiting plate (1); one end of each of the three clamping rods (2) has a round hole, and the round hole at the end of the clamping rod (2) forms a rotating pair with the three cylindrical protruding shafts of the circular outer shell limiting plate (1); the other end of each of the three clamping rods (2) is provided with a cylindrical protruding shaft; both ends of each of the three driven rods (3) have round holes, and one end forms a rotating pair with the cylindrical protruding shaft of the clamping rod (2);

[0008] The power transmission and control device comprises, from top to bottom: a drive gear disc (4), a return spring (5), a mating roller (6), and a limiting base (7); the return spring (5) is fixed to the lower surface of the drive gear disc (4); the mating roller (6) has a central hole through which the lower shaft of the drive gear disc (4) passes and is concentric with the central hole of the mating roller (6); two limiting posts are provided on the limiting base (7), and two holes are provided at corresponding positions on the mating roller (6) for the limiting posts to pass through, forming an upper and lower horizontal kinematic pair between the mating roller (6) and the limiting base (7).

[0009] Furthermore, the lower part of the active gear disk (4) is provided with a long shaft that is connected to the rotary motor after the speed is adjusted by the reduction gearbox, serving as the power source for the entire device.

[0010] Furthermore, the aforementioned screwing clamping device, power transmission and control device are connected through a circular outer shell limiting plate (1), driven rod (3), active gear plate (4), and limiting base (7); the upper surface of the active gear plate (4) has four protruding shafts, and the central protruding shaft forms a rotating joint connection with the circular hole at the center of the circular outer shell limiting plate (1); the three protruding shafts that are close to the circumference of the active gear plate (4) are respectively connected to the three driven rods (3) to form a rotating joint connection; the limiting base (7) is provided with three sets of limiting grooves, which are fixed to the circular outer shell limiting plate (1).

[0011] Furthermore, the reset spring (5) is fixed to the active chuck gear disk (4). When the screwing device does not perform a screwing operation, the spring is in its original position and there is no elastic force in the spring. After the screwing device completes the screwing operation, the reset spring will return to the initial position of the chuck (6) that controls the operation.

[0012] Furthermore, the caliper wheel (6) is provided with a central hole, and the lower shaft of the drive gear disc (4) is concentric with the central hole of the caliper wheel (6) and is an interference fit.

[0013] Furthermore, the limiting base (7) is provided with three sets of limiting grooves and two limiting posts; the limiting grooves are used to fix the circular outer shell limiting plate (1) and the limiting base (7) to each other; two holes are provided at the corresponding positions on the matching chuck (6) for the limiting posts to pass through, and this fit is an interference fit; forming an upper and lower horizontal motion pair between the matching chuck and the limiting base (7); during the screwing process, after the clamping rod (2) of the screwing clamping device reaches the clamping connection position, the active chuck gear plate (4) and the matching chuck (6) mesh with each other, and mechanically lock the clamping rod (2) through the chuck teeth, so that it can no longer move relative to the circular outer shell limiting plate (1); thereafter, the entire screwing device structure is locked, forming the structure of a fixed wrench, and the screwing of the connection begins.

[0014] Furthermore, the power transmission and control device utilizes electromagnet control. Specifically, a permanent magnet is installed on the active gear disc (4), and a solenoid electromagnet is installed on the mating wheel (6). At the same time, a force sensor is set on the contact surface between the clamping rod (2) and the fastener. When the screwing device receives the sensor signal, that is, when the clamping rod clamps the screwed part, the rotary motor is stopped by controlling the power supply, and the electromagnet is energized. Under the action of electromagnetic force, the return spring (5) is compressed, and the mating wheel (6) and the active gear disc (4) mesh with each other. Under the action of the limiting base (7), the relative position of the holding rod is locked.

[0015] Furthermore, the screwing device is connected to the end of the robotic arm via a bearing, and a locking mechanism is also provided: under normal conditions, the locking mechanism is locked, and the screwing device is fixed to the robotic arm; when the entire screwing device has secured the connecting piece, the locking mechanism is unlocked, releasing the rotational freedom of the screwing device relative to the robotic arm, allowing it to complete the remaining process of screwing the connecting piece; the locking mechanism is also controlled by sensor signals, which determine whether the clamping rod has secured the connecting piece, thereby controlling the opening and closing of the locking mechanism.

[0016] This invention also discloses a method for screwing an external hexagonal component screwing device, characterized in that the screwing method includes the following steps:

[0017] Step 1: After the robotic arm identifies and approaches the connector to be screwed, the circular outer shell limiting plate (1) of the clamping device contacts the connector; after confirming the contact, the rotary motor drives the active clamping gear plate (4) to rotate, and the clamping rod (2) gradually approaches the connector to be screwed.

[0018] Step 2: After the clamping rod (2) clamps the screwed connecting piece, the rotary motor stops, and the cooperating chuck (6) moves upward under the action of electromagnetic force. Then the cooperating chuck (6) and the active chuck gear disk (4) mesh with each other. Under the action of the limiting base (7), the relative position of the clamping rod (2) is locked.

[0019] Step 3: The locking constraint between the end tool of the entire twisting device and the end of the robotic arm is released, the rotary motor is started, and the end tool of the entire twisting device is rotated relative to the end of the robotic arm until the twisted part is finished.

[0020] Furthermore, in step two: a permanent magnet is installed on the active chuck gear disk, a solenoid electromagnet is installed on the mating chuck wheel, and a force sensor is set on the contact surface between the clamping rod and the fastener; when the screwing device receives the sensor signal, i.e., when the three sets of clamping rods clamp the part being screwed, the rotary motor is stopped by controlling the power supply, and the electromagnet is energized; under the action of electromagnetic force, the return spring is compressed, and the teeth of the mating chuck wheel and the active chuck wheel mesh with each other. Under the action of the limiting base, the relative positions of the three sets of clamping rods are locked.

[0021] Throughout the process, one end of the return spring is fixed to the lower surface of the drive gear disk, and the other end is fixed to the upper surface of the mating roller. When the screwing device is not performing a screwing operation, the spring is in its original position and there is no elastic force in the spring. After the screwing device completes the screwing operation, the return spring is responsible for restoring the mating roller, which participates in the control function, to its initial position. It is required that the electromagnetic force after the electromagnet is energized is always greater than the spring force.

[0022] The advantages of this invention compared to the prior art are as follows:

[0023] This invention utilizes the principle of a four-bar linkage to solve the problem of low tightening torque through mechanical force transmission between the links. Furthermore, during the movement of the two sides, various types of external hexagonal parts can be tightened using different states. The device of this invention has a large tightening torque, can adapt to various types of external hexagonal parts, has a simple principle, and high structural reliability. Attached Figure Description

[0024] Figure 1 This is an isometric drawing of an external hexagonal part screwing device according to the present invention;

[0025] Figure 2 This is a schematic diagram of a screwing and clamping device for a screwing device for external hexagonal parts according to the present invention;

[0026] Figure 3 This is a schematic diagram of the power transmission and control device for a hexagonal part screwing device according to the present invention;

[0027] Among them, 1-circular outer shell limiting plate, 2-clamping rod, 3-driven rod, 4-drive locking gear plate, 5-reset spring, 6-matching locking wheel, 7-limiting base. Implementation

[0028] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following examples provide a more detailed description of the invention. It should be noted that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0029] like Figures 1-3 As shown, the device of the present invention includes: a screwing and clamping device and a power transmission and control device; the screwing and clamping device includes: a circular outer shell limiting plate 1, a clamping rod 2, and a driven rod 3. The power transmission and control device includes, from top to bottom: a driving gear plate 4, a return spring 5, a cooperating clamping wheel 6, and a limiting base 7; a long shaft is provided at the lower part of the driving gear plate 4 and is connected to a rotary motor whose speed is adjusted by a reduction gearbox, serving as the power source for the entire device.

[0030] The aforementioned screwing clamping device, power transmission and control device are connected via a circular outer shell limiting plate 1, driven rod 3, driving gear plate 4, and limiting base 7. The upper surface of the driving gear plate 4 has four protruding shafts, and the central protruding shaft forms a rotating joint with the circular hole at the center of the circular outer shell limiting plate 1. Three protruding shafts that are close to the circumference of the driving gear plate 4 are respectively connected to three driven rods 3, forming a rotating joint. The limiting base 7 is provided with three sets of limiting grooves, which are fixed to the circular outer shell limiting plate 1.

[0031] like Figure 2 As shown, the screw-clamping device includes: a circular outer shell limiting plate 1, three clamping rods 2, and three driven rods 3; three cylindrical protruding shafts are evenly distributed around the outer circumference of the circular outer shell limiting plate 1; one end of each of the three clamping rods 2 has a round hole, which forms a rotating joint with the three cylindrical protruding shafts of the circular outer shell limiting plate 1; the other end of each of the three clamping rods 2 has a cylindrical protruding shaft; both ends of each of the three driven rods 3 have round holes, and one end forms a rotating joint with the cylindrical protruding shaft of the clamping rod 2; among them, the three sets of linkage devices, the three clamping rods 2 and the three driven rods 3, are the main components of the entire part. Initially, the three clamping rods 2 are placed at a position slightly larger than the corresponding 56 mm screw-clamping external hexagonal connector, and are restricted by the maximum limit of the circular outer shell limiting plate 1. During the tightening operation, the driven rods 3 of the three linkage devices are simultaneously driven by the active chuck 4, and the three clamping rods 2 gradually retract, shrinking from the preset maximum size to the size of the part being tightened. Finally, the three clamping rods 2 directly contact the part being tightened.

[0032] Initially, the three clamping rods are positioned slightly larger than the corresponding 56 mm hexagonal connector, limited by the maximum limit of the circular housing limiting plate. During the tightening operation, the driven rods of the three linkage devices are simultaneously driven by the drive wheel, and the three clamping rods gradually retract from their preset maximum size to the size of the part being tightened. Finally, the three clamping rods directly contact the part being tightened.

[0033] like Figure 3As shown, the power transmission and control device of the present invention comprises, from top to bottom: a drive gear disk 4, a return spring 5, a mating roller 6, and a limiting base 7; the return spring 5 is fixed to the lower surface of the drive gear disk 4; the mating roller 6 has a central hole through which the lower shaft of the drive gear disk 4 passes and is concentric with the central hole of the mating roller 6; two limiting posts are provided on the limiting base 7, and two holes are provided at corresponding positions on the mating roller 6 for the limiting posts to pass through, forming a vertical horizontal kinematic pair between the mating roller 6 and the limiting base 7. A long shaft is provided at the lower part of the drive gear disk 4 and connected to a rotary motor after the speed is adjusted via a reduction gearbox, serving as the power source for the entire device. The drive gear disk 4 has four protruding shafts; the central shaft forms a rotating pair connection with the central hole of the circular outer shell limiting disk 1 of the screw-clamping device; three protrusions close to the circumference are respectively connected to the driven rods corresponding to the screw-clamping part, forming a rotating pair connection.

[0034] The lower shaft of the drive gearbox 4 is connected to the rotary motor after the speed is adjusted by the gearbox, serving as the power source for the entire device. The return spring 6 is fixed to the drive gearbox 4. When the screwing device is not performing a screwing operation, the spring is in its original position and there is no elastic force in the spring. After the screwing device completes the screwing operation, the return spring is responsible for restoring the mating chuck 6, which participates in the control function, to its initial position.

[0035] The locating roller 6 has a central hole, and the lower shaft of the driving gear 4 is concentric with this hole, forming an interference fit. The limiting base 7 has three sets of limiting grooves and two limiting posts. The limiting grooves are used to fix the circular outer shell limiting plate 1 and the limiting base 7 together; two holes are provided at corresponding positions on the locating roller 6 for the limiting posts to pass through, forming an interference fit. This creates a vertical horizontal kinematic pair between the locating roller and the limiting base. During the tightening process, after the clamping rod 2 of the tightening clamping device reaches the clamping position of the connecting piece, the driving gear 4 and the locating roller 6 mesh with each other, mechanically locking the clamping rod through the clamping teeth, preventing it from moving relative to the circular outer shell limiting plate. Afterward, the entire tightening device structure is locked, forming a structure similar to a fixed wrench, and the tightening of the connecting piece begins.

[0036] To enable the power transmission and control device to control the twisting process while reducing motor drive, this device utilizes electromagnets for control. A permanent magnet is mounted on the driving gear disc 4, and a solenoid electromagnet is mounted on the mating roller 6. A force sensor is also placed on the contact surface between the clamping rod 2 and the fastener. When the twisting device receives a sensor signal, indicating that the three sets of clamping rods 2 are clamping the part being twisted, the rotary motor is stopped via the control power supply, and the electromagnet is energized. Under the action of electromagnetic force, the return spring 6 is compressed, and the mating roller 6 and the driving gear disc 4 mesh together. Under the action of the limiting base 7, the relative positions of the three sets of clamping rods 2 are locked.

[0037] To ensure that the entire device retains one degree of rotational freedom for tightening parts even when locked, the device is connected to the end of the robotic arm via a bearing and includes a locking mechanism. Under normal conditions, the locking mechanism is engaged, fixing the tightening device to the robotic arm. Once the entire tightening device has clamped the connector, the locking mechanism unlocks, releasing the tightening device's rotational freedom relative to the robotic arm, allowing it to complete the remaining tightening process. The locking mechanism is also controlled by sensor signals, which determine whether the clamping rod is clamping the connector, thus controlling the opening and closing of the locking mechanism.

[0038] In summary, the present invention divides the entire working process of the rotating end effector into the following three steps:

[0039] After the robotic arm identifies and approaches the connector to be tightened, the circular outer shell limiting plate of the tightening part contacts the connector. Once contact is confirmed, the rotary motor drives the active chuck gear disk to rotate, and the three sets of clamping rods gradually approach the connector to be tightened.

[0040] After the three sets of clamping rods clamp the screwed connecting parts, the rotary motor stops, and the cooperating chuck moves upward under the action of electromagnetic force. Then, the cooperating chuck and the active chuck mesh with each other, and under the action of the limiting base, the relative positions of the three sets of clamping rods are locked. A permanent magnet is installed on the active gear plate, and a solenoid electromagnet is installed on the mating wheel. A force sensor is also placed on the contact surface between the clamping rods and the fasteners. When the tightening device receives a sensor signal (i.e., the three clamping rods clamp the part being tightened), the rotary motor stops via a control power supply, and the electromagnet is energized. Under the electromagnetic force, the return spring is compressed, and the mating wheel and the active gear mesh. Under the action of the limiting base, the relative positions of the three clamping rods are locked. Throughout the process, one end of the return spring is fixed to the lower surface of the active gear plate, and the other end is fixed to the upper surface of the mating wheel. When the tightening device is not performing a tightening operation, the spring is in its original position and has no elastic force. After the tightening device completes the tightening operation, the return spring is responsible for restoring the mating wheel, which participated in the control function, to its initial position. It is required that the electromagnetic force after the electromagnet is energized is always greater than the spring force.

[0041] Once the locking constraint between the entire screwing end tool and the end of the robotic arm is released, the rotary motor starts, causing the entire screwing end tool to rotate relative to the end of the robotic arm until the screwed part is finished.

[0042] The screwing device of this invention must be able to screw on hexagonal threaded connectors with an inner diameter of 24 mm to 56 mm, and simultaneously meet the requirement that the maximum screwing torque during the screwing process is not less than 15 N·m. After meeting the above conditions, the use of a motor should be minimized, and the space occupied by the tool should be reduced as much as possible.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A screwing device for external hexagonal parts, characterized in that, The device includes a movably connected screwing and clamping device and a power transmission and control device; The aforementioned screwing and clamping device includes: a circular outer shell limiting plate (1), three clamping rods (2), and three driven rods (3); three cylindrical protruding shafts are evenly distributed around the outer circumference of the circular outer shell limiting plate (1); one end of each of the three clamping rods (2) has a round hole, and the round hole at the end of the clamping rod (2) forms a rotating pair with the three cylindrical protruding shafts of the circular outer shell limiting plate (1); the other end of each of the three clamping rods (2) is provided with a cylindrical protruding shaft; both ends of each of the three driven rods (3) have round holes, and one end forms a rotating pair with the cylindrical protruding shaft of the clamping rod (2); The power transmission and control device comprises, from top to bottom: a drive gear disc (4), a return spring (5), a mating roller (6), and a limiting base (7); the return spring (5) is fixed to the lower surface of the drive gear disc (4); the mating roller (6) has a central hole through which the lower shaft of the drive gear disc (4) passes and is concentric with the central hole of the mating roller (6); two limiting posts are provided on the limiting base (7), and two holes are provided at corresponding positions on the mating roller (6) for the limiting posts to pass through, forming an upper and lower horizontal kinematic pair between the mating roller (6) and the limiting base (7); The aforementioned screwing clamping device, power transmission and control device are connected through a circular outer shell limiting plate (1), driven rod (3), active gear plate (4), and limiting base (7); the upper surface of the active gear plate (4) has four protruding shafts, and the central protruding shaft forms a rotating joint connection with the circular hole at the center of the circular outer shell limiting plate (1); the three protruding shafts that are close to the circumference of the active gear plate (4) are respectively connected to the three driven rods (3) to form a rotating joint connection; the limiting base (7) is provided with three sets of limiting grooves, which are fixed to the circular outer shell limiting plate (1); The return spring (5) is fixed to the drive gear disk (4); the mating cam (6) is provided with a center hole, the lower shaft of the drive gear disk (4) is concentric with the center hole of the mating cam (6), and is an interference fit; The limiting base (7) is provided with three sets of limiting grooves and two limiting posts; the limiting grooves are used to fix the circular outer shell limiting plate (1) and the limiting base (7) to each other; two holes are provided at the corresponding positions on the matching cam (6) for the limiting posts to pass through, and this fit is an interference fit; forming an upper and lower horizontal movement pair between the matching cam and the limiting base (7); The power transmission and control device uses electromagnets for control. Specifically, a permanent magnet is installed on the active chuck (4), a solenoid electromagnet is installed on the mating chuck (6), and a force sensor is set on the contact surface between the clamping rod (2) and the fastener. The screwing device is connected to the end of the robotic arm through a bearing, and a locking mechanism is also provided.

2. The external hexagonal part screwing device according to claim 1, characterized in that, The active gear disk (4) has a long shaft at its lower part connected to a rotary motor after the speed is adjusted by a reduction gearbox, which serves as the power source for the entire device.

3. The external hexagonal part screwing device according to claim 1, characterized in that, When the screwing device is not performing a screwing operation, the spring is in its original position and there is no elastic force in the spring; after the screwing device has completed the screwing operation, the reset spring will return to the initial position with the control action chuck (6).

4. The external hexagonal part screwing device according to claim 1, characterized in that, During the tightening process, after the clamping rod (2) of the tightening clamping device reaches the position of the clamping connector, the active locking gear disc (4) and the mating locking wheel (6) mesh with each other, and mechanically lock the clamping rod (2) through the locking teeth, so that it can no longer move relative to the circular outer shell limiting disc (1); thereafter, the entire tightening device structure is locked, forming the structure of a fixed wrench, and the tightening of the connector begins.

5. The external hexagonal part screwing device according to claim 1, characterized in that, When the screwing device receives the sensor signal, that is, when the clamping rod clamps the part being screwed, the rotating motor is stopped by controlling the power supply and the electromagnet is energized; under the action of electromagnetic force, the return spring (5) is compressed, and the chuck (6) meshes with the active chuck gear disc (4). Under the action of the limiting base (7), the relative position of the holding rod is locked.

6. The external hexagonal part screwing device according to claim 1, characterized in that, Under normal conditions, the gate locking mechanism is locked, and the screwing device is fixed to the robotic arm. Once the entire screwing device has secured the connecting piece, the gate locking mechanism unlocks, releasing the rotational freedom of the screwing device relative to the robotic arm, allowing it to complete the remaining process of screwing the connecting piece. The gate locking mechanism is also controlled by sensor signals, which determine whether the clamping rod has secured the connecting piece, thereby controlling the opening and closing of the gate locking mechanism.

7. A method for tightening an external hexagonal component tightening device according to any one of claims 1 to 6, characterized in that, The screwing method includes the following steps: Step 1: After the robotic arm identifies and approaches the connector to be screwed, the circular outer shell limiting plate (1) of the clamping device contacts the connector; after confirming the contact, the rotary motor drives the active clamping gear plate (4) to rotate, and the clamping rod (2) gradually approaches the connector to be screwed. Step 2: After the clamping rod (2) clamps the screwed connecting piece, the rotary motor stops, and the cooperating chuck (6) moves upward under the action of electromagnetic force. Then the cooperating chuck (6) and the active chuck gear disk (4) mesh with each other. Under the action of the limiting base (7), the relative position of the clamping rod (2) is locked. Step 3: The locking constraint between the end tool of the entire twisting device and the end of the robotic arm is released, the rotary motor is started, and the end tool of the entire twisting device is rotated relative to the end of the robotic arm until the twisted part is finished.

8. The method for tightening an external hexagonal component tightening device according to claim 7, characterized in that, Throughout the process, one end of the return spring is fixed to the lower surface of the drive gear disk, and the other end is fixed to the upper surface of the mating roller. When the screwing device is not performing a screwing operation, the spring is in its original position and there is no elastic force in the spring. After the screwing device completes the screwing operation, the return spring is responsible for restoring the mating roller, which participates in the control function, to its initial position. It is required that the electromagnetic force after the electromagnet is energized is always greater than the spring force.

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