Electric cylinder with controllable fall-back speed after power failure

Abstract

The present invention discloses an electric cylinder with controllable fallback speed upon power failure, comprising a forward and reverse motor, a speed limiter, a planetary gear reducer, a gear box and a cylinder barrel that are sequentially connected in transmission. The motor transmits power to the gear box through the speed limiter and the planetary gear reducer in sequence. The gear box drives the screw assembly and the piston rod assembly in the cylinder barrel to move up and down. The speed limiter includes a housing, an overspeed clutch is provided in the housing, a transition shaft is fixedly connected in the overspeed clutch, one end of the transition shaft is connected to the output end of the motor, and the other end is connected to the input end of the planetary gear reducer. The screw assembly stalls and falls, and power is transmitted to the transition shaft after being accelerated by the gear box and the planetary gear reducer. The transition shaft drives the motor to accelerate and reverse, and the overspeed clutch brakes the transition shaft to make the motor reverse at a uniform speed. In the above manner, the electric cylinder with controllable fallback speed upon power failure of the present invention can control the speed of the electric cylinder stalling and falling within a safe range.

Description

Technical Field

[0001] The present invention relates to the field of electric cylinders, and in particular to an electric cylinder with controllable fall-back speed when power is lost. Background Art

[0002] Conventional electric cylinders lack speed limiting devices. Retraction of the aerial work platform relies on controlling the motor to provide reverse torque, achieving a uniform descent. This method cannot retract the platform even when the motor is powered off, nor can it recover potential energy, resulting in significant energy waste and safety hazards. During emergency retraction of the aerial work platform, the electric cylinder's descent speed must be controlled within a certain range to prevent damage to electronic components caused by the back EMF current generated by the motor's reverse rotation. Summary of the Invention

[0003] The main technical problem solved by the present invention is to provide an electric cylinder with controllable falling speed upon power failure, which can control the falling speed of the electric cylinder within a safe range.

[0004] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide an electric cylinder with controllable power-off fall speed, comprising a forward and reversible motor, a speed limiter, a planetary gear reducer, a gear box and a cylinder barrel that are sequentially connected in transmission, the motor transmits power to the gear box through the speed limiter and the planetary gear reducer in turn, the gear box drives the screw assembly and the piston rod assembly in the cylinder barrel to move up and down, the speed limiter includes a housing, an overspeed clutch is provided in the housing, a transition shaft is fixedly connected to the overspeed clutch, one end of the transition shaft is connected to the output end of the motor, and the other end is connected to the input end of the planetary gear reducer, the screw assembly stalls and falls, the power is transmitted to the transition shaft after being increased in speed by the gear box and the planetary gear reducer, the transition shaft drives the motor to accelerate and reverse, and the overspeed clutch brakes the transition shaft to make the motor reverse at a uniform speed.

[0005] In a preferred embodiment of the present invention, the overspeed clutch includes a shaft sleeve, which is fixedly connected to the transition shaft, and mounting brackets are symmetrically provided at both ends of the shaft sleeve. The outer side of the mounting bracket is provided with a friction plate that is gap-matched with the box body. The left and right sides of the two mounting brackets are connected by a spring, and a counterweight block is further provided between the mounting bracket and the shaft sleeve, and sliding pads are installed between the left and right sides of the counterweight block and the shaft sleeve.

[0006] In a preferred embodiment of the present invention, the transition shaft accelerates and reverses to generate centrifugal force to cause friction braking between the friction plate and the box body, thereby generating a braking torque until the braking torque is equal to the reverse torque generated by the screw assembly due to gravity, and the motor reverses at a constant speed.

[0007] In a preferred embodiment of the present invention, an electromagnetic brake with a manual release switch is installed on the motor, and when the motor is powered off, pressing the manual release switch causes the screw assembly to stall and descend.

[0008] In a preferred embodiment of the present invention, the output end of the transition shaft is connected to the reducer sleeve of the planetary gear reducer, the reducer sleeve is connected to the sun gear, and the sun gear drives the planetary gears on the planetary gear carrier to output power through the output shaft on the planetary gear carrier.

[0009] In a preferred embodiment of the present invention, the screw assembly includes a ball screw and a screw nut, one end of the ball screw is connected to the gear box for transmission, and the piston rod assembly includes a piston and a piston rod, the left end of the piston is connected to the screw nut, and the right end is connected to the piston rod, the piston rod is sleeved on the outside of the ball screw, and the other end extends out of the cylinder and is connected to the rod head, and the gear box drives the ball screw to rotate so that the screw nut drives the piston rod to reciprocate.

[0010] In a preferred embodiment of the present invention, an inner support member is provided on the other end of the thread rolling screw, and the inner support member is movably matched with the inner wall of the piston rod of the piston rod assembly.

[0011] In a preferred embodiment of the present invention, the ball screw is also provided with a bearing inner sleeve, a bearing is mounted on the outer side of the bearing inner sleeve, an intermediate pin is provided on the outer side of the bearing, and the intermediate pin is connected between the gear box and the cylinder.

[0012] In a preferred embodiment of the present invention, the gearbox includes an upper gear, which is connected to the output shaft of the planetary gear reducer. The upper gear is also engaged with an idler gear, and the idler gear is engaged with a lower gear. The lower gear is fixedly connected to the ball screw to drive the ball screw to rotate.

[0013] The beneficial effects of the present invention are as follows: the electric cylinder with controllable power-off fallback speed can control the speed of the electric cylinder falling back after stalling within a safe range, preventing the back electromotive force current generated by the motor reversal from damaging electronic components, and at the same time recovering energy from the back electromotive force generated by the uniform speed reversal of the motor, thereby meeting the needs of emergency evacuation and potential energy recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0015] Figure 1This is a structural diagram of a preferred embodiment of the electric cylinder with controllable power-off fall speed according to the present invention;

[0016] Figure 2 yes Figure 1 Schematic diagram of the local structure;

[0017] Figure 3 yes Figure 2 Schematic diagram of the local structure;

[0018] Figure 4 yes Figure 1 Schematic diagram of the local structure;

[0019] The components in the accompanying drawings are marked as follows: 1. Motor, 2. Speed ​​limiter, 21. Housing, 22. Overspeed clutch, 23. Transition shaft, 24. Bushing, 25. Mounting frame, 26. Friction plate, 27. Spring, 28. Counterweight, 29. Sliding pad, 3. Planetary gear reducer, 31. Reducer sleeve, 4. Gearbox, 41. Upper gear, 42. Idle gear, 43. Lower gear, 5. Cylinder, 6. Electromagnetic brake, 61. Manual release switch, 7. Screw assembly, 71. Ball screw, 72. Screw nut, 73. Inner support, 74. Bearing inner sleeve, 75. Bearing, 76. Intermediate pin, 8. Piston rod assembly, 81. Piston, 82. Piston rod, 83. Rod head. DETAILED DESCRIPTION

[0020] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] See also Figures 1 to 4 , an electric cylinder with controllable fall-back speed when power is lost, comprising a forward and reversible motor 1, a speed limiter 2, a planetary gear reducer 3, a gear box 4 and a cylinder 5 which are sequentially connected in transmission. The motor 1 transmits power to the gear box 4 through the speed limiter 2 and the planetary gear reducer 3 in turn. The gear box 4 drives the screw assembly 7 and the piston rod assembly 8 in the cylinder 5 to move up and down. The speed limiter 2 comprises a box body 21, in which an overspeed clutch 22 is provided. A transition shaft 23 is fixedly connected to the overspeed clutch 22. One end of the transition shaft 23 is connected to the output end of the motor 1, and the other end is connected to the input end of the planetary gear reducer 3. The screw assembly 7 stalls and falls, and the power is transmitted to the transition shaft 23 after being accelerated by the gear box 4 and the planetary gear reducer 3. The transition shaft 23 drives the motor 1 to accelerate and reverse, and the overspeed clutch 22 brakes the transition shaft 23 to make the motor 1 reverse at a uniform speed.

[0022] In addition, the overspeed clutch 22 includes a shaft sleeve 24, which is fixedly connected to the transition shaft 23. Mounting brackets 25 are symmetrically provided at both ends of the shaft sleeve 24. The outer side of the mounting bracket 25 is provided with a friction plate 26 that is clearance-matched with the box body 21. The left and right sides of the two mounting brackets 25 are connected by a spring 27. A counterweight block 28 is also provided between the mounting bracket 25 and the shaft sleeve 24. Sliding pads 29 are installed between the left and right sides of the counterweight block 28 and the shaft sleeve 24.

[0023] In addition, the transition shaft 23 accelerates in reverse rotation, generating centrifugal force that causes friction plate 26 to brake against housing 21, thereby generating a braking torque. This torque is then equal to the counter torque generated by gravity on lead screw assembly 6, and motor 1 then reverses at a constant speed. The transition shaft 23 drives shaft sleeve 24 to rotate. When the shaft sleeve 24 rotates at a low speed, the overrunning clutch has no braking torque. When the speed reaches a certain value, the centrifugal force generated by the counterweight 28 causes friction plate 26 to contact housing 1, generating a braking torque. This torque is equal to the counter torque generated by gravity, thus reaching an equilibrium speed. This causes motor 1 to reverse at a constant speed, and lead screw assembly 7 to descend at a constant speed.

[0024] In addition, an electromagnetic brake 6 with a manual release switch 61 is installed on the motor 1. When the motor 1 is powered off, the manual release switch 61 is pressed to cause the screw assembly 7 to stall and descend.

[0025] In addition, the output end of the transition shaft 23 is connected to the reducer sleeve 31 of the planetary gear reducer 3. The reducer sleeve 31 is connected to the sun gear, which drives the planetary gears on the planetary gear carrier, outputting power through the output shaft of the planetary gear carrier. Conventional components of a planetary gear reducer, such as the sun gear, planetary gears, and planetary gear carrier, are not shown in the figure, but their specific structure is consistent with that of a conventional planetary gear reducer. The gearbox 4 includes an upper gear 41, which is connected to the output shaft of the planetary gear reducer 3. The upper gear 41 also meshes with an idler gear 42, which meshes with a lower gear 43. The lower gear 43 is fixedly connected to the ball screw 71 to drive the ball screw 71. The planetary gear reducer flange is connected to the gearbox housing via screws. The output shaft of the planetary gear reducer 3 is keyed to the upper gear 41, which meshes with the idler gear 42, which meshes with the lower gear 43. The lower gear 43 is keyed to the ball screw 71.

[0026] In addition, the screw assembly 7 includes a ball screw 71 and a screw nut 72. One end of the ball screw 71 is in transmission connection with the gearbox 4. The gearbox 4 drives the ball screw 71 to rotate, causing the screw nut 72 to drive the piston rod 82 to reciprocate. The other end of the ball screw 71 is provided with an internal support member 73, which flexibly engages with the inner wall of the piston rod 82. One end of the piston 81 is connected to the screw nut 72 (with an accompanying safety nut) by screws, and the other end of the piston 81 is connected to the piston rod 82 by screws. The rod head 83 is threadedly connected to the piston rod 82, and a through-hole mounting pin is provided after the connection to prevent loosening. The rod head 83 is connected to an external load (aerial work platform). The internal support member 73 is supported by the inner hole wall of the piston rod 82, supporting the end of the ball screw 71 and guiding the reciprocating motion of the piston rod 82.

[0027] In addition, the ball screw 71 is also provided with a bearing inner sleeve 74, the outer side of the bearing inner sleeve 74 is fitted with a bearing 75, the outer side of the bearing 75 is provided with an intermediate pin 76, and the intermediate pin 76 is connected between the gear box 4 and the cylinder 5.

[0028] The specific working principle of the electric cylinder with controllable power-off fall speed of the present invention is as follows:

[0029] The motor 1 is powered by an external battery and runs at the rated speed. The motor 1 drives the piston rod 82 of the cylinder 5 to rise through the speed limiter 2, the planetary gear reducer 3 and the gearbox 4 until the external load (the aerial work vehicle) reaches the highest position. At this time, the motor 1 is powered off and the electromagnetic brake 6 holds the rotor shaft of the motor 1 to prevent the piston rod 82 from falling back. During the above process, the overspeed clutch 22 does not limit the speed.

[0030] When the platform is urgently evacuated / potential energy is recovered, the manual release switch 61 of the electromagnetic brake 6 is pulled, and the electromagnetic brake 6 is opened. Due to the action of gravity, the piston rod 82 begins to accelerate and fall back. At this time, the ball screw 71 accelerates and rotates, driving the lower gear 43, the idler gear 42 and the upper gear 41 to accelerate synchronously. After the upper gear 41 transmits power to the planetary gear reducer 3, the speed is amplified and acts on the reducer sleeve 31. At this time, the transition shaft 23 is driven by the reducer sleeve 31 to start accelerating synchronously. Similarly, the rotor shaft of the motor 1 also starts to rotate synchronously. Accelerate the reversal. Since the transition shaft 23 is connected to the overspeed clutch 22 with a key, when the speed reaches the speed limit of the overspeed clutch, the centrifugal force generated by the counterweight 28 drives the mounting frame 25 and the friction plate 26 to move toward the housing 1, so that the friction plate 26 contacts the housing 1 and generates a braking torque. When the generated braking torque is equal to the reverse torque generated by gravity, the equilibrium speed is reached, and the motor 1 is in a state of uniform reversal. The piston rod 72 descends at a uniform speed, and finally the electric cylinder descends at a uniform speed. The motor 1 reverses to generate a back electromotive force for energy recovery.

[0031] Different from the existing technology, the electric cylinder of the present invention has a controllable power-off fallback speed, which can control the speed of the electric cylinder's stall fallback within a safe range, preventing the back electromotive force current generated by the motor's reversal from damaging electronic components. At the same time, the back electromotive force generated by the motor's uniform reversal is used to recover energy, meeting the needs of emergency evacuation and potential energy recovery.

[0032] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An electric cylinder with controllable fallback speed upon power failure, comprising a forward and reversible motor, a speed limiter, a planetary gear reducer, a gear box, and a cylinder barrel, which are sequentially connected in a transmission manner. The motor transmits power to the gear box through the speed limiter and the planetary gear reducer in sequence, and the gear box drives the screw assembly and piston rod assembly in the cylinder barrel to move up and down, characterized in that: The speed limiter includes a housing, an overspeed clutch is provided in the housing, the overspeed clutch is installed between the motor and the gear planetary reducer, a transition shaft is fixedly connected to the overspeed clutch, one end of the transition shaft is connected to the output end of the motor, and the other end is connected to the input end of the planetary gear reducer, The overspeed clutch includes a shaft sleeve, which is fixedly connected to the transition shaft. Mounting brackets are symmetrically provided at both ends of the shaft sleeve. Friction plates that are clearance-matched with the box body are provided on the outer sides of the mounting brackets. The left and right sides of the two mounting brackets are connected by springs. A counterweight is provided between the mounting bracket and the shaft sleeve. Sliding pads are installed between the left and right sides of the counterweight and the shaft sleeve. The screw assembly stalls and descends, and the power is transmitted to the transition shaft after being accelerated by the planetary gear reducer through the gear box. The transition shaft drives the motor to accelerate and reverse, and the overspeed clutch brakes the transition shaft to make the motor reverse at a uniform speed; The transition shaft accelerates and reverses to generate centrifugal force to make the friction plate and the box brake and generate braking torque until the braking torque is equal to the reverse torque generated by the gravity of the screw assembly, and the motor reverses at a constant speed. The motor is equipped with an electromagnetic brake with a manual release switch. When the motor is powered off, pressing the manual release switch causes the screw assembly to stall and descend. The output end of the transition shaft is connected to the reducer sleeve of the planetary gear reducer, the reducer sleeve is connected to the sun gear, and the sun gear drives the planetary gears on the planetary gear carrier to output power through the output shaft on the planetary gear carrier.

2. The electric cylinder with controllable fall-back speed upon power failure according to claim 1, characterized in that: The screw assembly includes a ball screw and a screw nut, one end of the ball screw is connected to the gear box for transmission, and the piston rod assembly includes a piston and a piston rod, the left end of the piston is connected to the screw nut, and the right end is connected to the piston rod. The piston rod is sleeved on the outside of the ball screw, and the other end extends out of the cylinder and is connected to the rod head. The gear box drives the ball screw to rotate so that the screw nut drives the piston rod to reciprocate.

3. The electric cylinder with controllable fall-back speed upon power failure according to claim 2, characterized in that: An inner support piece is provided on the other end of the ball screw, and the inner support piece is movably matched with the inner wall of the piston rod of the piston rod assembly.

4. The electric cylinder with controllable fall-back speed upon power failure according to claim 3 is characterized in that: The ball screw is also provided with a bearing inner sleeve, the outer side of the bearing inner sleeve is fitted with a bearing, the outer side of the bearing is provided with an intermediate pin shaft, and the intermediate pin shaft is connected between the gear box and the cylinder.

5. The electric cylinder with controllable fall-back speed upon power failure according to claim 4 is characterized in that: The gear box includes an upper gear, which is connected to the output shaft of the planetary gear reducer. The upper gear is also engaged with an idler gear, and the idler gear is engaged with a lower gear. The lower gear is fixedly connected to the ball screw to drive the ball screw to rotate.

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