The present invention relates to the field of automatic control systems, and more particularly, to a screw-driven control system.
A screw-driven control system, which is generally a motor-driven screw stem, drives a nut assembly disposed on the screw stem to reciprocate, thereby driving a controlled object connected with the nut assembly. Generally speaking, the screw-driven control system is mostly applied to the field of rail doors and electrically operated doors, and also has locking and unlocking functions. The screw-driven control system, which is generally applied to the above-mentioned fields, locks the nut assembly by an electromagnetic lock, thereby realizing the function of locking the door. For this type of screw-driven control system, the electromagnetic lock must be energized at any time to ensure the door locking stability. If the electromagnetic lock is de-energized, there is a risk when the door is automatically unlocked. However, most of the structures of locking the door by a mechanical lock in the prior art have the problem of complicated structures. As a system mainly composed of mechanical structures, complicated structures will bring problems such as poor reliability, big dead weight, and difficulty in control, and will threaten the personal safe of passengers especially when being applied to public transportation.
Object of the present invention: the present invention provides a screw-driven control system to solve the problem that the door in the door system using the electromagnetic lock in the prior art is automatically unlocked after being de-energized, and the problems that the door system using the mechanical lock has complicated structure, big dead weight, and difficulty in control.
Technical solutions: in order to solve the foregoing technical problems, the screw-driven control system of the present invention comprises a driving mechanism fixed in a cross beam, a guide locking piece and a limiting mechanism. The driving mechanism comprises a screw rod and a nut assembly driven by a motor; the nut assembly comprises a transmission frame, a nut sleeved in the screw rod, and a follow-up member fixed in the nut; the nut is mounted in the transmission frame, and the transmission frame is connected with a controlled object; the screw rod drives the nut assembly to reciprocate axially along the screw rod; during the forward rotation of the screw rod, when the follow-up member is contacted with the guide locking piece, the follow-up member moves to the limiting mechanism under the guiding of an upper surface of the guide locking piece and is blocked by the limiting mechanism, then the follow-up member rotates with the screw rod to enter a space between a side plane of the guide locking piece and the limiting mechanism and is locked; and when the screw rod rotates reversely, the follow-up member reversely rotates with the screw rod to disengage from the limitation of the guide locking piece and is unlocked, and then moves axially along the screw rod.
Further, the transmission frame has a mechanism for defining a range of angles at which the nut rotates with the screw rod, thereby restricting a large angle of rotation of the follow-up member due to vibration when the nut moves.
Further, the transmission frame has a mounting portion connected with the controlled object, the mounting portion extends upwards to form a nut mounting portion composed of four uprights, the nut is mounted in a space formed by the four uprights, and a limiting pin for defining a range of angles at which the nut rotates with the screw rod is mounted in top ends of the two uprights in a side facing the cross beam.
Further, an outer diameter of the nut is greater than a distance between the uprights at two sides, so the nut is confined in the space between the two uprights. When the nut moves axially along the screw rod, the transmission frame is driven to move together with the nut by applying a thrust to the uprights on different sides.
Further, the nut is composed of an inner ring and an outer ring, the inner ring is threadedly matched with the screw rod, and the outer ring sleeve is sleeved in the inner ring and is matched with the inner ring through an anti-slip gear, and one side of the outer ring facing the cross beam is outwards extended with a mounting base of the follow-up member.
Further, the mounting base has a screw hole, the follow-up member has a screw stem, and the screw stem is screwed into the screw hole to fixedly connect the follow-up member with the nut.
Further, the follow-up member is a roller, and the roller is matched with the guide locking piece to minimize a running resistance of the nut assembly when passing through a surface of the guide locking piece, and improve the system stability.
Further, the two sides of the outer ring of the nut are respectively located between the corresponding adjacent uprights, and the screw rod drives the transmission frame to rotate axially along the screw rod through the outer ring of the nut.
Further, the nut assembly further comprises an elastic member that applies a torsional force to the nut.
Further, the elastic member is a torsion spring, one end of the torsion spring rests on the transmission frame, and the other end of the torsion spring rests on the nut. The torsion spring adopts a model with an inner diameter larger than the diameter of the screw rod and is sleeved outside the screw rod.
Further, the outer ring of the nut is outwards extended with a stopper, and one end of the torsion spring rests on the stopper.
Further, the guide locking piece has a smooth upper surface that guides the follow-up member to move towards a limiting plate.
Further, the guide locking piece has a side plane facing the limiting plate, and a space enabling the follow-up member to fall into is formed between the side plane and the limiting mechanism.
Further, the side plane is an inclined plane that can restrict the follow-up member to pop up.
Further, an included angle between the side plane and a vertical plane is 0 to 10 degrees. In this angle range, the guide locking piece can apply an acting force to the follow-up member without causing the problem of locking the follow-up member due to excessive angle. The angle is 3 degrees preferably.
Further, a slide rail for moving the follow-up member is further provided, the slide rail is connected with the guide locking piece and is in smooth transition with the upper surface of the guide locking piece. The slide rail is arranged to move the follow-up member under the restriction of the slide rail, which can further increase the movement stationarity of the nut assembly.
Further, the limiting mechanism comprises a limiting plate mounted in the cross beam, the limiting plate has a side plane facing the guide locking piece, the side plane and the side plane of the guide locking piece constitute a space enabling the follow-up member to fall into.
Further, the limiting plate is rotatably mounted in the cross beam by a pin shaft, and one side of the limiting plate facing the guide locking piece has a bent vertical plate; and a return spring is arranged between the limiting plate and the pin shaft.
Further, the limiting plate is capable of triggering a signal switch during a rotating motion.
Further, the limiting plate is provided with a waist-shaped hole, a limiting pin is mounted in the cross beam, and the limiting pin extends into the waist-shaped hole to limit angle of rotation of the limiting plate.
Further, the limiting mechanism comprises a manual mechanism that comprises a fixed bracket mounted in the cross beam and a movable bracket mounted in the pin shaft, a return spring is mounted between the two brackets, and the movable bracket is driven to rotate around the pin shaft by a manual pulling rope, and can pull the follow-up member out from the space between the guide locking piece and the limiting plate during rotation.
Further, the movable bracket and the limiting plate are mounted in the same pin shaft. The two do not interfere with each other, and have a high integration degree, which can save the mounting space.
Beneficial effects: according to the screw-driven control system of the present invention, the combination of the nut assembly with the guide locking piece and the limiting mechanism solves the problem of safety risk caused by the automatic unlocking of the electromagnetic lock in the prior art when the electromagnetic lock fails, and is also simpler and more reliable than the existing mechanical lock structure, and the nut assembly is simpler in structure and more stable in operation than the form of being matched with a runner in the prior art. Since the number of members constituting the screw-driven control system is small, the screw-driven control system is easy to machine and has a small dead weight, and does need too much mounting space.
The invention is further explained with reference to the drawings hereinafter.
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The screw-driven control system of the present invention has a compact cooperation between the nut assembly 3 and the guide locking piece 51 and the limiting members, the structure of each member is relatively simple, and is stable during operation and is not easy to fail. Moreover, due to the simple structure, the mass of the entire system can be reduced, and the production cost can be decreased, and the system has a good effect when being applied to fields including rail transit, vehicles and the like in large area.
The screw-driven control system of the present invention can be divided into the following motion processes and states:
1. Electrically locking: the controller sends a signal to the motor 1 to cause the motor 1 to drive the screw rod 2 to rotate, and the screw rod 2 drives the follow-up member 7 to move axially along the screw rod 2 to the limiting mechanism 4 through the nut assembly 3; when the follow-up member 7 is contacted with the guide locking piece 51, the follow-up member moves to the limiting plate 13 under the guiding of the upper surface of the guide locking piece 51 and is blocked by the limiting plate 13. The follow-up member 7 rotates with the screw rod 2 into the space between the side plane of the guide locking piece 51 and the limiting plate 13 and is locked. In the process, the limiting plate 13 rotates to trigger the signal switch 15 arranged under the limiting plate. After the signal switch 15 sends an in-position signal to the controller, the controller controls the motor 1 to stop running and complete locking.
2.Electrically unlocking: the controller sends a signal to the motor 1 to cause the motor 1 to drive the screw rod 2 to rotate reversely, and the follow-up member 7 reversely rotates with the screw rod 2 to disengage from the limitation of the guide locking piece 51 and is unlocked, and disengaged from the limiting plate 13. The limiting plate 13 is returned under the action of the torsion spring to trigger the signal switch 15 to send an unlocking signal to the controller, then the limiting member moves axially along the screw rod 2. When the follow-up member 7 moves to the other end of the screw rod 2, the motor 1 stops running.
3. Manually locking: the controlled object 6 is manually driven to move the nut assembly 3 axially from the screw rod 2 to the limiting mechanism 4. At this moment, the screw rod 2 rotates passively. When the follow-up member 7 is contacted with the guide locking piece 51, the follow-up member moves to the limiting plate 13 under the guiding of the upper surface of the guide locking piece 51 and is blocked by the limiting plate 13. The follow-up member 7 rotates with the screw rod 2 into the space between the side plane of the guide locking piece 51 and the limiting plate 13 and is locked. During this process, the limiting plate 13 rotates to trigger the signal switch 15 arranged under the limiting plate. After the signal switch 15 sends an in-position signal to the controller, the controller controls the motor 1 to stop running and complete locking.
4. Manually unlocking: in a locked state, by rotating the unlocking switch, the manual pulling rope 8 pulls the movable bracket 17 to rotate clockwise around the pin shaft 14, and the poking block 21 of the movable bracket 17 pokes the follow-up member 7 from the lower portion to make the follow-up member 7 leave the locking position, and meanwhile, the torsion spring drives limiting plate 13 to rotate clockwise around the pin shaft 14 and triggers the signal switch 15. After the unlocking switch is released, the movable bracket 17 is driven by the return spring to rotate to the initial position, and then the controlled object 6 is manually driven to move the nut assembly 3 axially from the screw shaft 2 towards a direction away from the limiting mechanism 4 to realize manual unlocking.
The descriptions above are merely preferable embodiments of the invention, and it should be noted that those of ordinary skills in the art may make a plurality of improvements and decorations without departing from the principle of the invention, and these improvements and decorations shall also fall within the protection scope of the invention.
Number | Date | Country | Kind |
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20160046335.6 | Jan 2016 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2016/072481 | 1/28/2016 | WO | 00 |