Soft start safety protector for electric motor

Abstract

A kind of soft start safety protector of motor, including soft starter body and soft start safety coupling, soft start safety coupling is mechanically connected between motor and load, the soft start safety coupling includes rack, driving shaft and driven shaft, and torsion limiting protector is arranged between driving shaft and driven shaft, and torsion limiting protector includes driving pulley, driven pulley, left bridge wheel, right bridge wheel, bridge axle, support and distance regulator.Soft starter body realizes the soft start and soft parking function of motor by circuit;Soft start safety coupling is used for safety transmission, is driven by two pairs of belt transmission, has multiple skid point positions, and is tensioned using distance regulator, can adjust the upper limit of torsion transmission, is used in conjunction with soft starter body, and the safety performance is higher, improves the safety in the process of motor start-stop.

Description

TECHNICAL FIELD

[0001] The present application relates to a soft starter, in particular to a soft start safety protector of a motor. BACKGROUND

[0002] Because the impact current is very large when the motor is directly started, especially the direct start of the large-capacity motor will cause interference to the power grid and other loads, and even harm the safe operation of the power grid, so many kinds of reduced voltage starting methods are adopted according to different working conditions, and the soft starter is widely used. The working principle of the soft starter is that the control circuit uses different methods to control the conduction angle of the three-phase anti-parallel thyristor, so that the input voltage of the motor gradually increases from zero to a preset function relationship, until the start is completed, the full voltage of the motor is given, and the soft start is realized. In the process of starting and stopping the motor by the soft starter, if the output end of the motor is blocked, the risk of burning the motor and other electronic elements is large. SUMMARY

[0003] The present application solves the problems existing in the prior art, and provides a soft start safety protector of a motor, which can adjust the upper limit of the torque transmission and cooperate with the soft starter body to work, thereby improving the safety during the starting and stopping of the motor.

[0004] The technical scheme adopted by the present application to solve the technical problem is as follows: a soft start safety protector of a motor, comprising a soft starter body and a soft start safety coupling, the soft starter body is electrically connected between a power supply and a motor, and the soft start safety coupling is mechanically connected between the motor and a load, the soft start safety coupling comprises a rack, a driving shaft and a driven shaft, the left and right ends of the rack are respectively rotatably installed with the driving shaft and the driven shaft, the driving shaft and the driven shaft are respectively used to fixedly connect the output end of the motor and the input end of the load, a torque limiting protector is arranged between the driving shaft and the driven shaft, the torque limiting protector comprises a driving pulley, a driven pulley, a left bridge pulley, a right bridge pulley, a bridge shaft, a support and a distance adjuster, the driving pulley and the driven pulley are respectively fixedly installed on the driving shaft and the driven shaft, the left bridge pulley and the right bridge pulley are fixedly installed on the two ends of the bridge shaft, the driving pulley and the left bridge pulley are connected by a belt, the driven pulley and the right bridge pulley are connected by a belt, the bridge shaft is rotatably installed on the support, and the support and the rack are fixedly connected by the distance adjuster.

[0005] Further improvement, the bridge shaft is composed of left and right two shaft sleeves, and an overload safety lever is fixedly connected between the two shaft sleeves.

[0006] Further improvement, the overload bumper and the shaft sleeve are circumferentially fixed and axially slidingly connected, the overload bumper is made of several sections of materials with different torsional fracture values, the electric telescopic rod is fixedly installed on the support, and the telescopic end of the electric telescopic rod is rotationally connected to one end of the overload bumper.

[0007] Further improvement, the overload bumper is integrally formed with a protruding key strip, and the key strip is slidingly connected to the key groove arranged on the inner hole of the shaft sleeve.

[0008] Further improvement, the telescopic end of the electric telescopic rod and one end of the overload bumper are respectively fixedly installed with a first magnet and a second magnet, the first magnet and the second magnet are attracted to each other, and a first thrust bearing is arranged between the first magnet and the second magnet.

[0009] Further improvement, the driving shaft and the driven shaft are located on the same axis, and two or more than two torsion limiting protectors are circumferentially and uniformly distributed around the axis.

[0010] Further improvement, the driving shaft and the driven shaft are located on the same axis, and two or more than two torsion limiting protectors are circumferentially and uniformly distributed around the axis.

[0011] Further improvement, the clutch includes a telescopic air bag, a sleeve, a movable tooth disc and a fixed tooth disc, the fixed tooth disc is fixedly installed on the driving shaft or the driven shaft, the movable tooth disc is fixedly installed on the sleeve, the sleeve is circumferentially fixed and axially slidingly connected between the brake shaft, the sleeve is provided with a return tension spring, the fixed support is fixedly connected with the telescopic air bag, and a second thrust bearing is arranged between the telescopic air bag and the movable tooth disc.

[0012] Further improvement, the soft starter body includes a control module, a voltage regulator, a bypass contactor and a power switch, the power supply is connected to the input ends of the voltage regulator and the bypass contactor, the output ends of the voltage regulator and the bypass contactor are connected to the input end of the power switch, the output end of the power switch is connected to the motor, and the voltage regulator, the bypass contactor, the power switch and the distance regulator are electrically connected with the control module.

[0013] Further improvement, the driving shaft and the driven shaft are located on the same axis, and two or more than two torsion limiting protectors are circumferentially and uniformly distributed around the axis.

[0014] The application has the beneficial effects that the application comprises a soft starter main body electrically connected between a power supply and a motor and a soft start safety coupling mechanically connected between the motor and a load, the soft starter main body realizes the soft start and soft stop functions of the motor through a circuit; the soft start safety coupling is used for safe transmission, transmits through two pairs of belt transmission, has multiple slip points, and is tensioned by a distance adjuster, the upper limit of the torsion transmission can be adjusted, the soft starter main body is used in cooperation, the safety performance is higher, and the safety during the start and stop of the motor is improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a structural block diagram of the application;

[0016] Figure 2 It is a structural schematic diagram of the soft start safety coupling;

[0017] Figure 3 It is an enlarged structural schematic diagram of the overload bumper;

[0018] Figure 4 It is an enlarged structural schematic diagram of the brake;

[0019] The reference signs are explained as follows: 1, rack, 2, driving shaft, 3, driven shaft, 4, driving pulley, 5, driven pulley, 6, left bridging wheel, 7, right bridging wheel, 8, support, 9, distance adjuster, 10, belt, 11, overload bumper, 12, electric telescopic rod, 13, key strip, 14, key groove, 15, first magnet, 16, second magnet, 17, first thrust bearing, 18, fixed support, 19, brake shaft, 20, disc brake, 21, telescopic air bag, 22, sleeve, 23, movable toothed disc, 24, fixed toothed disc, 25, reset tension spring, 26, second thrust bearing, 27, torque sensor, 28, bridging shaft. DETAILED DESCRIPTION

[0020] The application is further described below in combination with the drawings:

[0021] The drawings are referred to Figures 1-2The soft start safety protector of the motor in the embodiment 1 comprises a soft starter body and a soft start safety coupling, the soft starter body is electrically connected between the power supply and the motor, the soft start safety coupling is mechanically connected between the motor and the load, the soft start safety coupling comprises a rack 1, a driving shaft 2 and a driven shaft 3, the driving shaft 2 and the driven shaft 3 are rotatably installed at the left and right ends of the rack 1 respectively, the driving shaft 2 and the driven shaft 3 are used for fixedly connecting the output end of the motor and the input end of the load respectively, a torsion limiting protector is arranged between the driving shaft 2 and the driven shaft 3, the torsion limiting protector comprises a driving pulley 4, a driven pulley 5, a left bridge wheel 6, a right bridge wheel 7, a bridge shaft 28, a support 8 and a distance adjuster 9, the driving pulley 4 and the driven pulley 5 are fixedly installed on the driving shaft 2 and the driven shaft 3 respectively, the left bridge wheel 6 and the right bridge wheel 7 are fixedly installed at the two ends of the bridge shaft, the driving pulley 4 and the left bridge wheel 6 and the driven pulley 5 and the right bridge wheel 7 are connected through the belts 10 respectively, the bridge shaft is rotatably installed on the support 8, and the support 8 is fixedly connected with the rack 1 through the distance adjuster 9.

[0022] Working principle: the soft starter body makes the motor input voltage gradually increase from zero to the preset function relationship until the start ends, the full voltage is given to the motor, the soft start is realized, in the soft start process, the motor starting torque and the rotating speed gradually increase, the motor drives the driving shaft 2 to rotate, the driving shaft 2 drives the driving pulley 4 to rotate, the left bridge wheel 6, the bridge shaft 28 and the right bridge wheel 7 are driven to rotate through the belt, the right bridge wheel 7 drives the driven pulley 5 and the driven shaft 3 through the belt, and the input shaft of the load (such as a speed reducer) is driven to rotate through the driven shaft 3, so that the power transmission is completed, the rotating speed of the motor changes from slow to fast, the friction force generated by the belt changes from large to small, and once the friction force is too large during the starting process, the two belts will slip one by one, so that the torque will not be too large, and the function of soft start is realized. The torsion limiting protector can adjust the tension of the belt through the distance adjuster 9 (a telescopic element such as a pneumatic cylinder or an electric cylinder), so as to realize the adjustment of the upper limit of the torsion transmission; when the load exceeds the torque set by the torsion limiting protector, the two belts will slip, the instantaneous impact force is reduced when the load end is stationary, at this time, the distance adjuster 9 can control the belt to relax, realize the block of the torsion transmission, protect the normal operation of the motor end, realize the safety protection of the motor under the overload condition, reduce the maintenance cost, and improve the work efficiency.

[0023] The driving shaft 2 and the driven shaft 3 are located on the same axis, and the two or more torsion limiting protectors are uniformly distributed around the axis. Such arrangement can make the driving shaft 2 and the driven shaft 3 bear force more uniformly and move more stably, and the torsion limiting protector can be conveniently stacked for use.

[0024] In the embodiment 2, on the basis of the embodiment 1, as shown in the attached Figure 3As shown, the upper limit of the torque transmission defined by the belt will float due to the sliding friction and the maximum static friction. In order to further improve the safety of the transmission, the bridging shaft 28 is composed of two shaft sleeves, and an overload bumper 11 is fixedly connected between the two shaft sleeves. The overload bumper 11 has a specified torque breaking value (torque strength). When the torque value borne by the bridging shaft 28 is greater than the specified value, the overload bumper 11 will instantaneously break into two sections, so that the power between the left and right sections of the bridging shaft 28 is cut off, thereby achieving safety protection.

[0025] The overload bumper 11 is circumferentially fixed and axially slidably connected with the shaft sleeve. The overload bumper 11 is made of several sections of materials with different torque breaking values. An electric telescopic rod 12 is fixedly installed on the support 8, and the telescopic end of the electric telescopic rod 12 is rotatably connected with one end of the overload bumper 11. When the electric telescopic rod 12 is telescoped, it can drive the overload bumper 11 to axially slide, so that a section of material with a different torque breaking value is located at the gap in the middle of the bridging shaft 28, thereby achieving replacement of the rated torque value. When the torque values of the sections of material on the overload bumper 11 are the same, replacing the section located at the gap can prolong the service life of the overload bumper 11 and avoid accidental fatigue fracture.

[0026] The overload bumper 11 is integrally formed with a protruding key bar 13. The key bar 13 can enhance the structural strength of the overload bumper 11, and the key bar 13 is slidably connected with a key groove 14 arranged on the inner hole of the shaft sleeve. The overload bumper 11 is connected with the shaft sleeve by the key connection, which is a circumferential fixation and axial sliding connection.

[0027] The telescopic end of the electric telescopic rod 12 and one end of the overload bumper 11 are respectively fixedly installed with a first magnet 15 and a second magnet 16. The first magnet 15 and the second magnet 16 are attracted to each other, and a first thrust bearing 17 is arranged between the first magnet 15 and the second magnet 16.

[0028] In Example 3, on the basis of Examples 1 or 2, as shown in the attached Figure 4As shown, the brake is arranged between the driving shaft 2 and the driven shaft 3, and comprises a fixed support 18, a brake shaft 19, a disc brake 20 and a clutch. The brake shaft 19 is rotatably arranged on the fixed support 18, and the disc brake 20 is arranged between the brake shaft 19 and the fixed support 18. The two ends of the brake shaft 19 are respectively provided with a clutch between the driving shaft 2 and the driven shaft 3. When the motor is soft stopped, the voltage is reduced by the soft starter body, and the speed is reduced by the brake. The clutch can realize power connection or disconnection between the brake shaft 19 and the driving shaft 2 / driven shaft 3. When the brake shaft 19 is connected with the driving shaft 2 / driven shaft 3, the brake shaft 19 is driven by the driving shaft 2 / driven shaft 3, and the disc brake 20 is used to brake and slow down the brake shaft 19, so as to reduce the speed of the driving shaft 2 / driven shaft 3. The fixed support 18 is fixedly connected with the rack.

[0029] The clutch comprises a telescopic air bag 21, a sleeve 22, a movable gear disc 23 and a fixed gear disc 24. The fixed gear disc 24 is fixedly arranged on the driving shaft 2 or the driven shaft 3, the movable gear disc 23 is fixedly arranged on the sleeve 22, the sleeve 22 is circumferentially fixedly and axially slidably connected with the brake shaft 19, the sleeve 22 is provided with a reset tension spring 25, the fixed support 18 is fixedly connected with the telescopic air bag 21, and the telescopic air bag 21 is provided with a second thrust bearing 26 between the telescopic air bag 21 and the movable gear disc 23. The telescopic air bag 21 is controlled to stretch and retract by a charging and discharging pump. When the telescopic air bag 21 is inflated, the telescopic air bag 21 is elongated, the sleeve 22 is moved, the movable gear disc 23 is combined with the fixed gear disc 24, power connection is realized, when the telescopic air bag 21 is deflated, the telescopic air bag 21 is retracted, the sleeve 22 is retracted under the action of the reset tension spring 25, the movable gear disc 23 is separated from the fixed gear disc 24, and power disconnection is realized.

[0030] In embodiment 4, on the basis of any one of embodiments 1-3, the soft starter body comprises a control module, a voltage regulator, a bypass contactor and a power switch. The power supply is respectively connected with the input ends of the voltage regulator and the bypass contactor. The output ends of the voltage regulator and the bypass contactor are connected with the input end of the power switch. The output end of the power switch is connected with the motor. The voltage regulator, the bypass contactor, the power switch and the distance regulator 9 are electrically connected with the control module. The voltage regulator can adjust the voltage of the input end of the motor. The voltage regulator mainly comprises three-phase anti-parallel thyristors, realizes soft start, and switches to the bypass contactor after the start is completed. The bypass contactor provides full voltage to the motor, and prolongs the service life of the voltage regulator.

[0031] The driving shaft 2 and the driven shaft 3 are respectively provided with a torque sensor 27, and the torque sensor 27 is electrically connected with the control module. The torque sensor 27 can detect the torque value transmitted by the driving shaft 2 and the driven shaft 3, and timely find abnormal conditions. According to the torque values of the two, the control module can control the voltage regulator, the bypass contactor and the power switch to act, and timely perform soft start or soft stop control, so as to avoid greater safety accidents.

[0032] While the application has been illustrated and described in connection with preferred embodiments thereon, it will be readily apparent to those of ordinary skill in the art that various changes in form and detail can be made without departing from the spirit and scope of the application.

Claims

1. A soft start safety protector of an electric motor, comprising a soft starter body and a soft start safety coupling, the soft starter body being electrically connected between a power supply and the motor, the soft start safety coupling being mechanically connected between the motor and a load, characterized in that: The soft start safety coupling comprises a rack (1), a driving shaft (2) and a driven shaft (3), the driving shaft (2) and the driven shaft (3) are rotatably installed at the left and right ends of the rack (1) respectively, the driving shaft (2) and the driven shaft (3) are used for fixedly connecting the output end of a motor and the input end of a load respectively, a torque limiting protector is arranged between the driving shaft (2) and the driven shaft (3), the torque limiting protector comprises a driving pulley (4), a driven pulley (5), a left bridge wheel (6), a right bridge wheel (7), a bridge shaft (28), a support (8) and a distance adjuster (9), the driving pulley (4) and the driven pulley (5) are fixedly installed on the driving shaft (2) and the driven shaft (3) respectively, the left bridge wheel (6) and the right bridge wheel (7) are fixedly installed at the two ends of the bridge shaft, the driving pulley (4) and the left bridge wheel (6) and the driven pulley (5) and the right bridge wheel (7) are connected through a belt (10) respectively, the bridge shaft (28) is rotatably installed on the support (8), and the support (8) is fixedly connected with the rack (1) through the distance adjuster (9); the motor drives the driving shaft (2) to rotate, the driving shaft (2) drives the driving pulley (4) to rotate, the left bridge wheel (6), the bridge shaft (28) and the right bridge wheel (7) are driven to rotate through the belt, the right bridge wheel (7) drives the driven pulley (5) and the driven shaft (3) through the belt, the driven shaft (3) drives the input shaft of the load to rotate, so that power transmission is completed, the rotating speed of the motor changes from slow to fast, the friction force generated by the belt changes from large to small, once the friction force is too large during the starting process, the two belts will slip one by one, so that the torque will not be too large, and the function of soft start is realized; the torque limiting protector can adjust the tension of the belt through the distance adjuster (9), so that the upper limit of torque transmission is adjusted; when the load exceeds the torque set by the torque limiting protector, the two belts will slip, the instantaneous impact force is reduced when the load end is stationary, at this time, the distance adjuster (9) can control the belt to relax, so that the torque transmission is blocked, and the normal operation of the motor end is protected; The driving shaft (2) and the driven shaft (3) are further provided with a brake, the brake comprises a fixed support (18), a brake shaft (19), a disc brake (20) and a clutch, the fixed support (18) is rotatably installed with the brake shaft (19), the disc brake (20) is arranged between the brake shaft (19) and the fixed support (18), and each of the two ends of the brake shaft (19) is provided with a clutch between the driving shaft (2) and the driven shaft (3), the clutch comprises a telescopic air bag (21), a sleeve (22), a movable tooth disc (23) and a fixed tooth disc (24), the fixed tooth disc (24) is fixedly installed on the driving shaft (2) or the driven shaft (3), the movable tooth disc (23) is fixedly installed on the sleeve (22), the sleeve (22) is circumferentially fixed and axially slidably connected with the brake shaft (19), the sleeve (22) is provided with a return tension spring (25) therein, the fixed support (18) is fixedly connected with the telescopic air bag (21), and the telescopic air bag (21) is provided with a second thrust bearing (26) between the movable tooth disc (23).

2. A soft start safety protector for an electric motor as claimed in claim 1 wherein: The bridge axle is composed of left and right two axle sleeves, and an overload bumper (11) is fixedly connected between the two axle sleeves.

3. A soft start safety protector for an electric motor as claimed in claim 2 wherein: The overload bumper (11) is circumferentially fixed and axially slidably connected with the axle sleeve, the overload bumper (11) is made of several sections of materials with different torsion breaking values, an electric telescopic rod (12) is fixedly installed on the support (8), and a first magnet (15) and a second magnet (16) are respectively fixedly installed on the telescopic end of the electric telescopic rod (12) and one end of the overload bumper (11).

4. A soft start safety protector for an electric motor as claimed in claim 3 wherein: The overload bumper (11) is integrally formed with a protruding key strip (13), and the key strip (13) is slidably connected with a key groove (14) arranged on the inner hole of the axle sleeve.

5. A soft start safety protector for an electric motor as claimed in claim 3 wherein: The first magnet (15) and the second magnet (16) are mutually attracted, and a first thrust bearing (17) is arranged between the first magnet (15) and the second magnet (16).

6. A soft start safety protector for an electric motor as claimed in claim 1, wherein: The driving shaft (2) and the driven shaft (3) are located on the same axis, and the two or more than two torsion limiting protectors are circumferentially and uniformly distributed around the axis.

7. A soft start safety protector for an electric motor as claimed in claim 1, wherein: The soft starter body comprises a control module, a voltage regulator, a bypass contactor, a power switching switch, the power is respectively connected with the input ends of the voltage regulator and the bypass contactor, the output ends of the voltage regulator and the bypass contactor are connected with the input end of the power switching switch, the output end of the power switching switch is connected with the motor, and the voltage regulator, the bypass contactor, the power switching switch and the distance regulator (9) are electrically connected with the control module.

8. A soft start safety protector for an electric motor as claimed in claim 7 wherein: The driving shaft (2) and the driven shaft (3) are located on the same axis, and the two or more than two torsion limiting protectors are circumferentially and uniformly distributed around the axis.

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