A screw drive based on double motor synchronous drive

Abstract

The utility model discloses a screw rod drive device based on double motor synchronous drive belongs to screw rod drive device technical field, including screw rod drive device and controlling means, and the screw rod drive device is by the same structure first transmission unit and second transmission unit is composed, and first transmission unit includes first motor, and the output shaft of first motor is connected with first reverser through first speed reducer, and first reverser output end is connected with first screw rod, second transmission unit includes second motor, and the output shaft of second motor is connected with second reverser through second speed reducer, and second reverser output end is connected with second screw rod, and first screw rod is connected with second screw rod with same load, and through controlling means control two motor synchronous rotation, and through programmable controller and frequency changer control two motor synchronous drive, compared with single motor through mechanical drive device drive's double screw rod lifting device, and transmission precision has improved, and transmission efficiency has been improved obviously.

Description

Technical Field

[0001] This utility model belongs to the technical field of lead screw transmission devices, specifically a lead screw transmission device based on dual-motor synchronous drive. Background Technology

[0002] Screw-driven lifting devices are widely used in the industrial field. Traditional screw-driven devices are mostly single screw drives, which are prone to "jamming" or "torsion" when the load is eccentric, and have limited load-bearing capacity.

[0003] The load of a dual-screw drive lifting device is shared by two sets of screws, theoretically allowing for a maximum load capacity twice that of a single drive. Furthermore, the dual system reduces stress on individual screws by distributing the load, extending their service life. Therefore, dual-screw drive lifting systems offer significant advantages in industrial applications, particularly suitable for scenarios involving large spans, high precision, heavy loads, or stringent rigidity requirements.

[0004] Currently, most commonly used dual-screw drive systems involve a single motor driving two screws to rotate synchronously through a mechanical transmission device. For example... Figure 1 The high-power electroslag furnace electrode lifting system shown uses a motor to drive a reducer. A cross commutator is connected to the output shaft of the reducer. The output shafts at both ends of the cross commutator are connected to two commutators through a transmission shaft. Lead screws are connected to the two commutators. The motor of the electroslag furnace is driven to lift and lower by the synchronous rotation of the two lead screws.

[0005] However, the drawbacks of the above-mentioned device are that the mechanical structure is too complex, resulting in low transmission efficiency. At the same time, due to the transmission gap or transmission error of the mechanical transmission device, especially the cumulative error of multiple transmission devices, the synchronization accuracy of the lead screws on both sides is not ideal. In addition, the above-mentioned device also has problems such as large space occupation, high maintenance costs of high-power motors and complex mechanical transmission components, and heavy equipment weight.

[0006] For the reasons mentioned above, there is a need to develop a screw drive device driven synchronously by two motors, which uses electrical control synchronization to replace mechanical transmission synchronization. Utility Model Content

[0007] This invention proposes a lead screw transmission device based on dual-motor synchronous drive, aiming to solve the problems of low transmission efficiency and poor synchronization accuracy of existing single-motor driven dual-lead screw lifting transmission devices.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A lead screw drive device based on dual-motor synchronous drive includes a lead screw drive device and a control device. The lead screw drive device consists of a first transmission unit and a second transmission unit with identical structures. The first transmission unit includes a first motor, the output shaft of which is connected to a first commutator via a first reducer, and the output end of the first commutator is connected to a first lead screw. The second transmission unit includes a second motor, the output shaft of which is connected to a second commutator via a second reducer, and the output end of the second commutator is connected to a second lead screw. The first lead screw and the second lead screw are connected to the same load.

[0010] The control device includes a first frequency converter, a second frequency converter, and a programmable controller. The output terminals of the first frequency converter are connected to the first motor, and the output terminals of the second frequency converter are connected to the second motor. The input power terminals of the first and second frequency converters are connected to a three-phase power supply. The digital output terminal of the programmable controller is connected to the digital input terminal of the first frequency converter. The first and second frequency converters are connected through a communication terminal, and the first frequency converter sends the torque data of the first motor to the second frequency converter through the communication terminal.

[0011] Preferably, a first torque sensor is connected between the first commutator and the first reducer, and a second torque sensor is connected between the second commutator and the second reducer. The first torque sensor and the second torque sensor are respectively connected to the analog input terminal of the programmable controller. A main circuit breaker is provided on the three-phase power supply, and the switch control terminal of the main circuit breaker is connected to the switch output terminal of the programmable controller.

[0012] Preferably, the digital output terminal of the programmable controller is connected to the digital input terminals of the first frequency converter and the second frequency converter, respectively.

[0013] Preferably, the communication port of the programmable controller is connected to a host computer or an industrial Ethernet bus.

[0014] Preferably, the first frequency converter and the second frequency converter are of the same model, both being 6SE70 vector frequency converter controllers.

[0015] Preferably, the programmable controller is an S7-300PLC, and the S7-300PLC is connected to a host computer or an industrial Ethernet bus via an RS-485 serial port.

[0016] Beneficial effects: Compared with the prior art, the present invention can achieve at least the following technical effects;

[0017] 1. This utility model controls the movement of two lead screws through two motors, and controls the synchronous drive of the two motors through a programmable controller and a frequency converter. Compared with the double lead screw lifting device driven by a single motor through a mechanical transmission device, the transmission accuracy is improved.

[0018] 2. This utility model omits the complex mechanical transmission device. By controlling the synchronous drive of two motors through programs and circuits, the transmission efficiency is improved. Tests have proven that the synchronous drive of two 24kW motors can completely replace the 55kW high-power motor in the original single-motor screw transmission device.

[0019] 3. This utility model sets torque sensors between the reducers and commutators on both sides. The programmable controller can compare the data of the two rotation sensors. When a motor on one side fails, the difference between the torque sensors on both sides exceeds the threshold. The programmable controller will instruct the main circuit breaker to disconnect, so as to avoid damage to the motor or frequency converter and has good safety.

[0020] 4. This utility model proposes two master-slave control schemes: the speed command can be transmitted only to the master inverter via a programmable controller, or the speed command can be transmitted to both the master and slave inverters simultaneously, allowing for flexible selection based on actual load characteristics. This results in wider applicability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a single-motor driven dual-screw transmission device in the prior art.

[0022] Figure 2 This is a schematic diagram of the screw drive device of this utility model.

[0023] Figure 3 This is a schematic diagram of the control device connection in Embodiment 1 of this utility model.

[0024] Figure 4 This is a schematic diagram of the control device connection in Embodiment 2 of this utility model.

[0025] In the diagram, 1. First commutator; 2. First torque sensor; 3. First reducer; 4. First motor; 5. First lead screw; 6. Second lead screw; 7. Second commutator; 8. Second torque sensor; 9. Second reducer; 10. Second motor; 11. First frequency converter; 12. Second frequency converter; 13. Main circuit breaker; 14. Programmable controller;

[0026] 15. Left lead screw; 16. Central motor; 17. Central reducer; 18. Right lead screw; 19. Right commutator; 20. Right drive shaft; 21. Cross commutator; 22. Left drive shaft; 23. Left commutator. Detailed Implementation

[0027] The present invention will be further explained below with reference to specific implementation examples.

[0028] Taking the electrode lifting system of a certain type of high-power electroslag furnace as an example, Figure 1The diagram illustrates the lead screw drive system in an existing electroslag furnace motor lifting system. A 55kW central motor 16 drives a cross commutator 21 via a central reducer 17. The output shafts at both ends of the cross commutator 21 drive right commutators 19 and left commutators 23 via right drive shaft 20 and left drive shaft 22, respectively. The left commutator 23 and right commutator 19 then drive left lead screw 15 and right lead screw 18 to rotate synchronously, thus lifting and lowering the load. Because the central motor 16 requires multiple sets of transmission devices to drive the lead screws on both sides to rotate synchronously, the same power components and transmission chains inevitably suffer from differences in mechanical characteristics, machining precision issues, and varying wear. The cumulative errors of the multi-stage mechanical transmission devices result in poor synchronization of the lead screws on both sides. Furthermore, the multi-stage mechanical transmission devices lead to low transmission efficiency.

[0029] This invention proposes a lead screw transmission device based on dual-motor synchronous drive. It utilizes a combination of PLC and frequency converter to control two motors to synchronously drive two lead screws to rotate, replacing the traditional lead screw lifting device that uses a single motor to drive two lead screws through a mechanical transmission device, thereby improving transmission efficiency and synchronization accuracy.

[0030] Example 1

[0031] Please see Figure 1 , Figure 2 In this embodiment, a screw drive device based on dual-motor synchronous drive includes a screw drive device and a control device. The screw drive device consists of a first transmission unit and a second transmission unit with identical structures. The first transmission unit includes a first motor 4, the output shaft of which is connected to a first commutator 1 via a first reducer 3, and the output end of the first commutator 1 is connected to a first screw 5. The second transmission unit includes a second motor 10, the output shaft of which is connected to a second commutator 7 via a second reducer 9, and the output end of the second commutator 7 is connected to a second screw 6. The first screw 5 and the second screw 6 are connected to the same load.

[0032] The control device includes a first frequency converter 11, a second frequency converter 12, and a programmable controller 14. The output terminal of the first frequency converter 11 is connected to the first motor 4, and the output terminal of the second frequency converter 12 is connected to the second motor 10. The input power terminals of the first frequency converter 11 and the second frequency converter 12 are connected to a three-phase power supply. The digital output terminal of the programmable controller 14 is connected to the digital input terminal of the first frequency converter 11. The first frequency converter 11 and the second frequency converter 12 are connected through a communication terminal. The first frequency converter 11 sends the torque data of the first motor 4 to the second frequency converter 12 through the communication terminal.

[0033] In this embodiment, the first frequency converter 11 serves as the master frequency converter, the second frequency converter 12 serves as the slave frequency converter, and the programmable controller 14 is only connected to the first frequency converter 11. It sends motor speed commands to the first frequency converter 11 through the digital output port. The first frequency converter 11 controls the first motor 4 to rotate according to the speed commands issued by the programmable controller 14. At the same time, the first frequency converter 11 transmits the torque data of the first motor 4 to the second frequency converter 12 through the communication interface. The second frequency converter 12, as the slave frequency converter, will follow and control the second motor 10 to rotate according to the torque data of the first frequency converter 11, thereby achieving the purpose of synchronous driving of the first motor 4 and the second motor 10. The first motor 4 drives the first lead screw 5 to rotate through the first reducer 3 and the first commutator 1, and the second motor 10 drives the second lead screw 6 to rotate through the second reducer 9 and the second commutator 7, thereby making the first lead screw 5 and the second lead screw 6 rotate synchronously.

[0034] In this embodiment, a first torque sensor 2 is connected between the first commutator 1 and the first reducer 3, and a second torque sensor 8 is connected between the second commutator 7 and the second reducer 9. The first torque sensor 2 and the second torque sensor 8 are respectively connected to the analog input terminals of the programmable controller 14. A main circuit breaker 13 is provided on the three-phase power supply, and the switch control terminal of the main circuit breaker 13 is connected to the switch output terminal of the programmable controller 14.

[0035] When one of the two motors or two frequency converters fails, the output torque of one motor is insufficient or it stops working. Due to the self-locking characteristic of the lead screw, the motor on the other side will experience abnormal torque or become stuck, which will cause the motor or frequency converter on the other side to burn out. For this reason, in this embodiment, a torque sensor is installed between the reducer and the commutator of each transmission unit. When the motor or frequency converter on one side fails, the torque data of the torque sensor on the other side will rise abnormally. The torque sensor data on both sides is transmitted to the programmable controller 14 through the analog input port. When the programmable controller 14 detects that the difference between the torque values ​​of the two torque sensors exceeds the set threshold, it will control the main circuit breaker 13 to disconnect the three-phase power supply through the switch output, thus protecting the motor and frequency converter.

[0036] In this embodiment, the programmable controller 14 is a Siemens S7-300 PLC. The S7-300 PLC does not require any additional hardware, software, or programming. The programmable controller 14 is connected to the host computer or industrial Ethernet bus via RS485 or RS232.

[0037] In this embodiment, the first frequency converter 11 and the second frequency converter 12 are selected as 6SE70 vector frequency converters. Vector frequency converters (Vector Variable Frequency Drives) are high-performance motor control devices in the field of industrial automation. Their core is to achieve precise decoupling control of the motor's torque and speed through field-oriented control (FOC). In this embodiment, the first frequency converter 11 and the second frequency converter 12 transmit data through X102.21.22 and X102.17.18 interfaces. The first frequency converter 11 operates in speed mode and controls the first motor 4 according to the speed command of the programmable controller 14. The second frequency converter 12 operates in torque mode, and its torque value is set by the first frequency converter 11. The first frequency converter 11 transmits information to the second frequency converter 12 by means of a digital PWM duty cycle signal.

[0038] Example 2

[0039] Based on Embodiment 1, in this embodiment, the digital output terminal of the programmable controller 14 is connected to the digital input terminals of the first frequency converter 11 and the second frequency converter 12, respectively.

[0040] In other words, in the above configuration, the programmable controller 14 simultaneously transmits the speed command to the first inverter 11 and the second inverter 12. The initial speed value transmitted by the programmable controller 14 to the second inverter 12 is slightly higher than the initial speed value transmitted to the first inverter 11. Therefore, the torque of the second motor 10 is slightly higher (0.5% to 1.5% higher) than that of the first motor 4. Based on this, the torque of the first motor 4 is used as the upper limit. The programmable controller 14 forms a closed-loop control based on the torque values ​​of the first torque sensor 2 and the second torque sensor 8, limiting the torque of the second motor 10 to be consistent with that of the first motor 4. The synchronization accuracy of this embodiment is improved compared with that of embodiment 1, but the algorithm is relatively complex. Those skilled in the art can select a suitable control method according to actual needs.

[0041] In the description of this utility model, the term "multiple" refers to two or more. Unless otherwise explicitly defined, the terms "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. The terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0042] In the description of this utility model, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In this utility model, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A lead screw transmission device based on dual-motor synchronous drive, characterized in that, The system includes a lead screw drive and a control device. The lead screw drive consists of a first transmission unit and a second transmission unit with the same structure. The first transmission unit includes a first motor (4), the output shaft of which is connected to a first commutator (1) via a first reducer (3), and the output end of the first commutator (1) is connected to a first lead screw (5). The second transmission unit includes a second motor (10), the output shaft of which is connected to a second commutator (7) via a second reducer (9), and the output end of the second commutator (7) is connected to a second lead screw (6). The first lead screw (5) and the second lead screw (6) are connected to the same load. The control device includes a first frequency converter (11), a second frequency converter (12), and a programmable controller (14). The output terminal of the first frequency converter (11) is connected to the first motor (4), and the output terminal of the second frequency converter (12) is connected to the second motor (10). The input power terminals of the first frequency converter (11) and the second frequency converter (12) are connected to a three-phase power supply. The digital output terminal of the programmable controller (14) is connected to the digital input terminal of the first frequency converter (11). The first frequency converter (11) and the second frequency converter (12) are connected through a communication terminal. The first frequency converter (11) sends the torque data of the first motor (4) to the second frequency converter (12) through the communication terminal.

2. The lead screw transmission device based on dual-motor synchronous drive according to claim 1, characterized in that, A first torque sensor (2) is connected between the first commutator (1) and the first reducer (3), and a second torque sensor (8) is connected between the second commutator (7) and the second reducer (9). The first torque sensor (2) and the second torque sensor (8) are respectively connected to the analog input terminal of the programmable controller (14). A main circuit breaker (13) is provided on the three-phase power supply, and the switch control terminal of the main circuit breaker (13) is connected to the switch output terminal of the programmable controller (14).

3. A screw transmission device based on dual-motor synchronous drive according to claim 2, characterized in that, The digital output terminal of the programmable controller (14) is connected to the digital input terminal of the first frequency converter (11) and the second frequency converter (12), respectively.

4. A lead screw transmission device based on dual-motor synchronous drive according to claim 1, characterized in that, The communication port of the programmable controller (14) is connected to a host computer or an industrial Ethernet bus.

5. A screw drive device based on dual-motor synchronous drive according to any one of claims 1-4, characterized in that, The first frequency converter (11) and the second frequency converter (12) are of the same model, both being 6SE70 vector frequency converter controllers.

6. A screw drive device based on dual-motor synchronous drive according to any one of claims 1-4, characterized in that, The programmable controller (14) is an S7-300PLC, which is connected to a host computer or industrial Ethernet bus via an RS-485 serial port.

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