A machine tool spindle brake energy recovery system for an electrodynamic chuck

Abstract

The application provides a machine tool spindle brake energy recovery system for an electric chuck, and relates to the technical field of machining equipment.The system comprises a spindle driving assembly, a regenerative electric energy recovery assembly, an energy storage assembly, an energy storage power supply assembly, a chuck driving assembly, an external power supply branch and a control unit.The regenerative electric energy recovery assembly is connected to a spindle DC bus, the energy storage assembly is connected to the output of the regenerative electric energy recovery assembly, the chuck driving power supply is connected to the energy storage assembly through the energy storage power supply and connected to an external power supply through the external power supply branch.The control unit acquires bus voltage and energy storage voltage;when the bus voltage exceeds a threshold value, the control unit controls the recovery assembly to charge at a reduced voltage;when a chuck action instruction is received, the control unit selects one power supply according to the comparison result of the energy storage voltage;the control unit acquires a chuck motor current signal, and cuts off the power supply after the action is completed.The application realizes the directional transfer and closed-loop utilization of the spindle brake energy to the chuck, and improves energy efficiency and power supply reliability.

Description

Technical Field

[0001] This invention relates to the field of machining equipment technology, and more specifically to a machine tool spindle braking energy recovery system for electric chucks. Background Technology

[0002] Against the backdrop of the deep integration of intelligent manufacturing and green manufacturing, CNC machine tools, as core equipment in modern manufacturing, are receiving increasing attention for their energy efficiency and level of intelligence. During the machining process, the spindle motor of the machine tool needs to frequently perform changes in operating conditions such as starting, accelerating, stabilizing, decelerating, and braking. Especially during the deceleration and braking phase, the drive motor will be in a regenerative braking state, generating a large amount of regenerative braking energy.

[0003] Currently, the industry commonly uses a braking resistor connected in series with the DC bus to dissipate this electrical energy as heat when dealing with the regenerative braking energy of the spindle motor. While this method is simple in structure and low in cost, it has significant drawbacks: Firstly, it directly wastes electrical energy, contradicting the development concept of green manufacturing; secondly, the accumulation of a large amount of heat inside the machine tool electrical cabinet leads to an increase in local ambient temperature, which not only affects the working stability and service life of the spindle drive and other precision control devices, but also increases the energy consumption of the air conditioning cooling system and the maintenance costs of the equipment.

[0004] With the development of power electronics technology, some high-end CNC machine tools have integrated regenerative energy feedback and grid connection functions into their spindle drive systems. This technology uses an active front end (AFE) or energy feedback unit to synchronously rectify and invert regenerative electrical energy before feeding it back to the grid, achieving macroscopic energy recovery. However, this grid-connected feedback scheme has significant shortcomings: First, its implementation requires complex grid-connected control algorithms, sine wave filtering, and harmonic suppression circuits, resulting in a complex system architecture and high hardware costs, making it difficult to promote and apply in the widely used low-to-mid-end CNC machine tools. Second, if the regenerative energy is not properly controlled during grid feedback, high-order harmonics can be introduced, polluting the power quality of the grid and potentially interfering with the stable operation of other precision equipment and the CNC system itself within the same grid.

[0005] On the other hand, electric chucks, as a new type of machine tool workpiece clamping device, use servo motors or stepper motors to directly drive the jaws to clamp and release the workpiece. Compared with traditional hydraulic or pneumatic chucks, they have significant advantages such as compact structure, fast response speed, high control precision, and no risk of hydraulic leakage, and are increasingly widely used in precision machining scenarios. However, during the instantaneous movement of an electric chuck, especially under heavy-load clamping, the drive motor needs to withstand a large peak torque, resulting in a high instantaneous power demand. Under the current technical architecture, the drive power of electric chucks is usually directly taken from the machine tool's auxiliary power supply or a separate external power supply. Its power supply link is independent of the spindle drive system, and there is a lack of energy coordination and interaction between the two.

[0006] In summary, the existing technology has at least the following technical problems: First, the regenerative energy generated by frequent spindle braking cannot be effectively and economically utilized locally, resulting in energy waste and thermal pollution; second, there is a lack of a technical solution that can match and directionally transfer the energy "generator" of spindle braking with the energy "consumption source" of electric chuck movement; third, in the case of multiple power supplies (i.e., energy storage power supply and external power supply), how to ensure the high reliability of the chuck movement power supply and the electrical safety when switching between the two power supplies is also a technical problem that urgently needs to be solved in this field.

[0007] In view of the above, this application is hereby submitted. Summary of the Invention

[0008] The present invention provides a machine tool spindle braking energy recovery system for electric chucks, which can at least partially improve the above-mentioned problems.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A machine tool spindle braking energy recovery system for an electric chuck includes: a spindle drive assembly, a regenerative energy recovery assembly, an energy storage assembly, an energy storage power supply assembly, a chuck drive assembly, an external power supply branch assembly, and a control unit. The input terminal of the regenerative energy recovery assembly is electrically connected to the DC bus of the spindle drive assembly. The input terminal of the energy storage assembly is electrically connected to the output terminal of the regenerative energy recovery assembly. The power supply terminal of the chuck drive assembly is electrically connected to the output terminal of the energy storage assembly through the energy storage power supply assembly. The output terminal of the external power supply branch assembly is electrically connected to the power supply terminal of the chuck drive assembly. The control unit is electrically connected to the spindle drive assembly, the regenerative energy recovery assembly, the energy storage power supply assembly, the external power supply branch assembly, and the chuck drive assembly. The control unit is configured to perform the following steps by executing a computer program stored internally thereon: The DC bus voltage of the spindle drive assembly and the energy storage voltage of the energy storage assembly are acquired in real time. When the DC bus voltage is found to be higher than the preset braking recognition threshold, the spindle is determined to be in regenerative braking state. The regenerative energy recovery component is controlled to reduce the voltage of the spindle regenerative braking energy of the spindle drive component and transmit it to the energy storage component for charging until the energy storage voltage reaches the preset energy storage upper limit threshold or the spindle braking ends. When a chuck action command signal is received, it is determined whether the energy storage voltage is higher than the preset discharge threshold. If so, disconnect the connection between the external power supply branch component and the chuck drive component, and connect the connection between the energy storage power supply component and the chuck drive component, so that the energy storage component supplies power to the chuck drive component to drive the chuck drive component to perform the corresponding action; If not, connect the external power supply branch component to the chuck drive component and disconnect the energy storage power supply component from the chuck drive component. The external power supply branch component supplies power to the chuck drive component to drive the chuck drive component to perform the corresponding action. The system acquires the chuck motor current signal and determines that the chuck action is complete based on the chuck motor current signal. Then, it disconnects the connection between the external power supply branch component and the chuck drive component, or disconnects the connection between the energy storage power supply component and the chuck drive component, and returns to the standby monitoring state.

[0010] Preferably, the spindle drive assembly includes a spindle power supply, a first circuit breaker, a first contactor, a first rectifier, a DC bus, a first inverter, and a spindle motor. The spindle power supply is connected to the input terminal of the first rectifier via the first circuit breaker and the first contactor. The output terminal of the first rectifier is connected to the DC bus. The DC bus is connected to the input terminal of the first inverter. The output terminal of the first inverter is connected to the spindle motor.

[0011] Preferably, the regenerative energy recovery component is a Buck converter circuit, including an input filter capacitor, a main switching device, a first inductor, a freewheeling diode, and an output filter capacitor. The control terminal of the main switching device is connected to the control unit, and the control unit controls the conduction and cutoff of the main switching device through a pulse width modulation signal. The main switching device is an insulated gate bipolar transistor (IGBT) or a power MOSFET.

[0012] Preferably, the energy storage component adopts a supercapacitor module, which has a built-in overvoltage protection unit, undervoltage protection unit and single-cell voltage equalization unit.

[0013] Preferably, the energy storage power supply component includes a second inductor, a first diode, a first MOSFET, a first capacitor, a fuse, a second MOSFET, and an anti-reverse current diode. The second inductor, the first diode, the first MOSFET, and the first capacitor constitute a Boost circuit. The Boost circuit is used to boost the energy storage voltage to the rated operating voltage of the chuck drive component. The anti-reverse current diode is used to suppress the reverse current of the side voltage of the chuck drive component to the energy storage component.

[0014] Preferably, the chuck drive assembly includes a second inverter and a chuck motor. The output terminal of the second inverter is connected to the chuck motor. The second inverter is used to convert input electrical energy into AC power required to drive the chuck motor. The chuck motor is used to perform chuck clamping or releasing actions under the drive of the second inverter.

[0015] Preferably, the external power supply branch assembly includes a chuck external power supply, a second circuit breaker, a second contactor, and a second rectifier. The chuck external power supply is connected to the input terminal of the second rectifier via the second circuit breaker and the second contactor. The output terminal of the second rectifier is connected to the input terminal of the second inverter.

[0016] Preferably, the control unit includes a control module, a first isolation drive circuit, a second isolation drive circuit, and a third isolation drive circuit. The output terminal of the control module is electrically connected to the input terminals of the first isolation drive circuit, the second isolation drive circuit, and the third isolation drive circuit. The output terminal of the first isolation drive circuit is electrically connected to the control terminal of the regenerative energy recovery component. The output terminals of the second and third isolation drive circuits are electrically connected to the control terminal of the energy storage power supply component.

[0017] Preferably, it further includes: when it is determined that the spindle stabilization condition and the chuck action permission condition are met, allowing the chuck drive component to perform a release action, and prohibiting the energy storage power supply component and the external power supply branch component from being simultaneously turned on during the chuck action, and outputting a protection control signal when the energy storage component is over-voltage, under-voltage or the power supply branch is over-current.

[0018] In summary, this system includes a spindle drive assembly, a regenerative energy recovery assembly, an energy storage assembly, an energy storage power supply assembly, a chuck drive assembly, an external power supply branch assembly, and a control unit. The input of the regenerative energy recovery assembly is connected to the DC bus of the spindle drive assembly. When the DC bus voltage rises due to spindle deceleration and braking, the regenerative braking energy of the spindle is stepped down and stored in the energy storage assembly. When the electric chuck performs clamping or releasing actions, the control unit controls the energy storage power supply assembly or the external power supply branch assembly to supply power to the chuck drive assembly based on the energy storage voltage. The energy storage power supply assembly boosts and stabilizes the output energy of the energy storage assembly before supplying it to the chuck drive assembly.

[0019] Compared with the prior art, the present invention realizes the directional transfer of spindle braking regenerative energy to electric chuck action energy, forming a local energy closed loop, and can automatically switch to external power supply when energy storage is insufficient, thereby improving the reliability of chuck action power supply and reducing braking energy dissipation. Attached Figure Description

[0020] Figure 1 This is an overall structural block diagram of a machine tool spindle braking energy recovery system for electric chucks provided in an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the circuit for recovering and utilizing the braking energy of a machine tool spindle for an electric chuck, provided in an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the control flow of a machine tool spindle braking energy recovery system for an electric chuck, provided in an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] refer to Figure 1 , Figure 2 As shown, the first embodiment of the present invention discloses a machine tool spindle braking energy recovery system for an electric chuck, which includes: a spindle drive assembly 10, a regenerative energy recovery assembly 20, an energy storage assembly 30, an energy storage power supply assembly 40, a chuck drive assembly 50, an external power supply branch assembly 60, and a control unit 70. The input end of the regenerative energy recovery assembly 20 is electrically connected to the DC bus 15 of the spindle drive assembly 10. The input end of the energy storage assembly 30 is electrically connected to the output end of the regenerative energy recovery assembly 20. The power supply end of the chuck drive assembly 50 is electrically connected to the output end of the energy storage assembly 30 through the energy storage power supply assembly 40. The output end of the external power supply branch assembly 60 is electrically connected to the power supply end of the chuck drive assembly 50. The control unit 70 is electrically connected to the spindle drive assembly 10, the regenerative energy recovery assembly 20, the energy storage power supply assembly 40, the external power supply branch assembly 60, and the chuck drive assembly 50.

[0025] Specifically, in this embodiment, the DC bus 15 of the spindle drive assembly 10 is used to drive the machine tool spindle motor; the regenerative energy recovery assembly 20 is used to reduce the output voltage of the spindle regenerative braking energy when the spindle motor 17 decelerates and brakes, causing the DC bus voltage to rise; the energy storage assembly 30 is used to store the energy output by the regenerative energy recovery assembly 20; the chuck drive assembly 50 is used to drive the electric chuck motor to perform clamping or releasing actions; the energy storage power supply assembly 40 includes at least a boost unit, a protection unit, a controlled switch unit, and a unidirectional isolation unit, used to controllably transmit the energy output by the energy storage assembly 30 to the chuck drive assembly 50 after boosting; the external power supply branch assembly 60 is used to supply power to the chuck drive assembly 50 when the voltage of the energy storage assembly 30 is lower than a preset discharge threshold or when the output of the energy storage assembly 30 cannot meet the chuck action requirements.

[0026] The control unit 70 is used to detect the DC bus voltage and the energy storage voltage, and control the regenerative energy recovery component 20 to charge the energy storage component 30 according to the detection results, and control the interlocking switching between the energy storage power supply component 40 and the external power supply branch component 60, so that the chuck drive component 50 is powered by one of the energy storage component 30 or the external power supply when the chuck is in motion.

[0027] Preferably, the spindle drive assembly 10 includes a spindle power supply 11, a first circuit breaker 12, a first contactor 13, a first rectifier 14, a DC bus 15, a first inverter 16, and a spindle motor 17. The spindle power supply 11 is connected to the input terminal of the first rectifier 14 via the first circuit breaker 12 and the first contactor 13. The output terminal of the first rectifier 14 is connected to the DC bus 15. The DC bus 15 is connected to the input terminal of the first inverter 16. The output terminal of the first inverter 16 is connected to the spindle motor 17.

[0028] Specifically, in this embodiment, when the spindle decelerates and brakes, the spindle motor 17 enters the regenerative power generation state, and the regenerative electrical energy generated is fed back to the DC bus 15 through the first inverter 16, thereby increasing the DC bus voltage.

[0029] Preferably, the regenerative energy recovery component 20 is a Buck converter circuit, including an input filter capacitor 21, a main switch 22, a first inductor 23, a freewheeling diode 24, and an output filter capacitor 25. The control terminal of the main switch 22 is connected to the control unit 70. The control unit 70 controls the on and off of the main switch 22 through a pulse width modulation signal to step down the regenerative energy on the DC bus 15 of the spindle drive component 10 and output it to the energy storage component 30. The main switch 22 is an insulated gate bipolar transistor (IGBT) or a power MOSFET. The control unit 70 is connected to the main switch 22 through a gate drive circuit.

[0030] In this embodiment, the regenerative energy recovery component 20 is connected between the DC bus 15 and the energy storage component 30. It is used to recover regenerative energy from the DC bus 15 during deceleration and braking of the spindle motor 17, and then step it down before outputting it to the energy storage component 30. Specifically, the input filter capacitor 21 is connected in parallel across the DC bus 15 to stabilize the input voltage; the MOSFET is the main switching device 22 of the Buck converter circuit; the first inductor 23, the freewheeling diode 24, and the output filter capacitor 25 constitute a step-down output circuit to convert the higher DC voltage on the DC bus 15 into a lower DC voltage suitable for charging the energy storage component 30. The control terminal of the main switching device 22 is connected to the control unit 70 via an isolation drive circuit. The control unit 70 outputs a pulse width modulation signal through the PWM1 pin, which drives the main switching device 22 to turn on and off via the isolation drive circuit, thereby adjusting the duty cycle of the Buck converter circuit and controlling the charging of the energy storage component 30.

[0031] The control unit 70 acquires the voltage signal of the DC bus 15 through the V1 pin and determines whether the spindle is in regenerative braking state based on the acquired voltage signal. When the control unit 70 detects that the DC bus voltage is higher than the preset braking recognition threshold, it determines that the spindle motor 17 is in regenerative braking state, outputs a PWM1 control signal, and enables the regenerative energy recovery component 20 to work, thereby transmitting the spindle regenerative braking energy to the energy storage component 30 after being stepped down by the main switching device 22, the first inductor 23, the freewheeling diode 24, and the output filter capacitor 25. The control unit 70 also acquires the voltage signal of the energy storage component 30 through the V2 pin.

[0032] Preferably, the energy storage component 30 adopts a supercapacitor module, which has a built-in overvoltage protection unit, undervoltage protection unit and single-cell voltage equalization unit to improve the safety and reliability of the charging and discharging process.

[0033] Specifically, in this embodiment, the energy storage component 30 is used to store the electrical energy recovered by the regenerative energy recovery component 20. The energy storage component 30 is preferably a supercapacitor module. Supercapacitor modules have the characteristics of fast charging and discharging speed, long cycle life, and high power density, making them suitable for absorbing regenerative electrical energy generated briefly during the deceleration and braking process of a machine tool spindle and rapidly releasing electrical energy during chuck operation.

[0034] When the voltage of the energy storage component 30 reaches the preset upper limit threshold for energy storage, the control unit 70 stops outputting the PWM1 signal, and the main switching device 22 stops working, thereby stopping the charging of the energy storage component 30 and preventing the energy storage component 30 from being overcharged.

[0035] Preferably, the energy storage power supply component 40 includes a second inductor 41, a first diode 42, a first MOSFET 43, a first capacitor 44, a fuse 45 (also called a circuit breaker), a second MOSFET 46, and an anti-reverse current diode 47. The second inductor 41, the first diode 42, the first MOSFET 43, and the first capacitor 44 constitute a boost circuit. The boost circuit is used to boost the energy storage voltage to the rated operating voltage of the chuck drive component 50. The anti-reverse current diode 47 is used to suppress the reverse current of the side voltage of the chuck drive component 50 to the energy storage component 30.

[0036] In this embodiment, the energy storage power supply component 40 is connected between the energy storage component 30 and the chuck drive component 50, and is used to boost the electrical energy output by the energy storage component 30 and send it to the chuck drive component 50 when the voltage of the energy storage component 30 meets the chuck operation requirements.

[0037] Specifically, the first MOSFET 43 is the switching device of the Boost converter circuit, and its control terminal is connected to the control unit 70 via an isolation drive circuit. The control unit 70 outputs a pulse width modulation signal through the PWM2 pin, which drives the first MOSFET 43 to turn on and off via the isolation drive circuit, so that the low-voltage DC power output by the energy storage component 30 is boosted and a DC voltage that meets the requirements of the chuck drive component 50 is established across the first capacitor 44.

[0038] A fuse 45 is connected in series in the output branch of the energy storage component 30 to cut off the circuit in case of abnormal overcurrent. The second MOSFET 46 is a controlled switch for the energy storage power supply path, and its control terminal is connected to the control unit 70 via an isolation drive circuit. The control unit 70 outputs a control signal to the isolation drive circuit through its Q pin to control the second MOSFET 46 to turn on or off. When the control unit 70 determines that energy storage power is being used, it controls the second MOSFET 46 to turn on, thus connecting the energy storage power supply path; when the control unit 70 determines that energy storage power is not being used, it controls the second MOSFET 46 to turn off, thus disconnecting the energy storage power supply path. An anti-reverse current diode 47 is located in the energy storage power supply output branch to prevent reverse current from the side voltage of the chuck drive component 50 to the energy storage power supply component 40 and the energy storage component 30.

[0039] Preferably, the chuck drive assembly 50 includes a second inverter 51 and a chuck motor 52. The output terminal of the second inverter 51 is connected to the chuck motor 52. The second inverter 51 is used to convert the input electrical energy into AC power required to drive the chuck motor 52. The chuck motor 52 is used to perform chuck clamping or releasing actions under the drive of the second inverter 51.

[0040] Specifically, in this embodiment, the chuck drive assembly 50 is used to drive the electric chuck to perform clamping or releasing actions.

[0041] Preferably, the external power supply branch assembly 60 includes a chuck external power supply 61, a second circuit breaker 62, a second contactor 63, and a second rectifier 64. The chuck external power supply 61 is connected to the input terminal of the second rectifier 64 via the second circuit breaker 62 and the second contactor 63. The output terminal of the second rectifier 64 is connected to the input terminal of the second inverter 51. That is, the external AC power supply is connected to the second rectifier 64 via the second contactor 63, and the output terminal of the second rectifier 64 is connected to the DC input terminal of the chuck drive assembly 50.

[0042] Specifically, in this embodiment, the external power supply branch component 60 is used to provide external power to the chuck drive component 50 when the voltage of the energy storage component 30 is insufficient to support the chuck operation; wherein, the second rectifier 64 is used to rectify the external AC power into DC power and then supply it to the second inverter 51, and the second inverter 51 then drives the chuck motor 52 to operate.

[0043] When the energy storage power supply component 40 is turned on, the control unit 70 controls the second contactor 63 to disconnect, and when the external power supply branch is turned on, the control unit 70 controls the controlled switch unit to turn off, so that the energy storage power supply component 40 and the external power supply branch component 60 are interlocked to prevent the two power supplies from being directly connected in parallel to supply power to the chuck drive component 50 at the same time.

[0044] Preferably, the control unit 70 includes a control module 74 (MCU, which includes PWM1, PWM2, M, Q, KM1, KM2, N, I, V1 and V2 pins), a first isolation drive circuit 71, a second isolation drive circuit 72, and a third isolation drive circuit 73. The output terminal of the control module 74 is electrically connected to the input terminals of the first isolation drive circuit 71, the second isolation drive circuit 72, and the third isolation drive circuit 73. The output terminal of the first isolation drive circuit 71 is electrically connected to the control terminal of the regenerative energy recovery component 20. The output terminals of the second isolation drive circuit 72 and the third isolation drive circuit 73 are electrically connected to the control terminal of the energy storage power supply component 40.

[0045] Among them, PWM1 is output to the first isolation drive circuit 71 to control the main switching device 22 in the regenerative energy recovery component 20; PWM2 is output to the second isolation drive circuit 72 to control the first MOSFET 43 in the energy storage power supply component 40; M and Q are used to output the chuck action control signal and the energy storage power supply enable control signal, respectively; KM1 and KM2 are used to control the first contactor 13 and the second contactor 63, respectively; N is used to collect the speed signal of the spindle motor 17; I is used to collect the current signal of the chuck motor 52; V1 is used to collect the voltage signal of the DC bus 15; and V2 is used to collect the voltage signal of the energy storage component 30.

[0046] The control unit 70 is used to determine whether the spindle is in regenerative braking state based on the DC bus voltage signal collected by V1, and to determine whether the energy storage meets the chuck operation requirements based on the voltage signal of the energy storage component 30 collected by V2. Based on the judgment results, it controls the operation of the regenerative energy recovery component 20, the energy storage power supply component 40, the external power supply branch component 60, and the chuck drive component 50.

[0047] Specifically, in this embodiment, when the spindle motor 17 is running normally, the spindle power supply 11 supplies power to the DC bus 15 via the first circuit breaker 12, the first contactor 13, and the first rectifier 14. The first inverter 16 drives the spindle motor 17 according to control commands. When the spindle motor 17 decelerates and brakes, it enters a regenerative power generation state. The regenerative energy it generates is fed back to the DC bus 15 via the first inverter 16, causing the DC bus voltage to rise. After the control unit 70 detects that the DC bus voltage is higher than the preset braking identification threshold via V1, it outputs a PWM1 signal, which drives the main switching device 22 to work via the first isolation drive circuit 71. This causes the regenerative energy recovery component 20 to step down the regenerative braking energy on the DC bus 15 and output it to the energy storage component 30 for charging. During the charging process, the control unit 70 monitors the voltage of the energy storage component 30 in real time via V2. When the voltage of the energy storage component 30 reaches the preset energy storage upper limit threshold or the spindle motor 17 stops completely, the control unit 70 stops the PWM1 signal output, thereby stopping the charging of the energy storage component 30.

[0048] When the control unit 70 receives a chuck clamping command or a chuck releasing command, it first determines whether the voltage of the energy storage component 30 detected by V2 meets the preset discharge threshold. When the voltage of the energy storage component 30 is higher than or equal to the preset discharge threshold, the control unit 70 prioritizes energy storage power supply and executes the following control: controls the second contactor 63 to open, so that the external power supply branch component 60 is in the open state; controls the second MOSFET 46 to turn on, so that the energy storage power supply path is connected; outputs a PWM2 signal, which drives the first MOSFET 43 to work through the second isolation drive circuit 72, so that the Boost boost circuit establishes the output voltage; the electrical energy output by the energy storage component 30 is delivered to the second inverter 51 after passing through the Boost boost circuit, fuse 45, second MOSFET 46 and anti-reverse current diode 47; the second inverter 51 drives the chuck motor 52 to perform clamping or releasing actions. When the voltage of the energy storage component 30 is lower than the preset discharge threshold, the control unit 70 controls the external power supply branch component 60 to supply power to the chuck motor 52 and performs the following control: controls the second MOSFET 46 to turn off, cutting off the energy storage power supply path; stops the PWM2 signal output, causing the first MOSFET 43 to stop working; controls the second contactor 63 to close, connecting the external power supply branch component 60; the external power supply 61 of the chuck supplies power to the second inverter 51 through the second circuit breaker 62, the second contactor 63 and the second rectifier 64; the second inverter 51 drives the chuck motor 52 to perform clamping or releasing actions.

[0049] To prevent the energy storage power supply component 40 and the external power supply branch component 60 from simultaneously supplying power to the chuck drive component 50, the control unit 70 interlocks the two power supply paths. Specifically, when the control unit 70 controls the second MOSFET 46 to conduct and uses energy storage power, it simultaneously controls the second contactor 63 to open; when the control unit 70 controls the second contactor 63 to close and uses external power, it simultaneously controls the second MOSFET 46 to turn off and stops the PWM2 signal output. This avoids direct parallel connection of the two power supplies and improves system operational safety.

[0050] The control unit 70 determines whether the chuck clamping or releasing action is complete based on the current change I of the chuck motor 52. When the control unit 70 determines that the chuck action is complete, if the current power supply is from the energy storage circuit, it controls the second MOSFET 46 to turn off and stops the PWM2 signal output, causing the first MOSFET 43 to stop working, thereby cutting off the energy storage power supply path; if the current power supply is from an external source, it controls the second contactor 63 to open, thereby cutting off the external power supply branch assembly 60. Furthermore, the chuck releasing action requires the spindle to be stationary. The control unit 70 sets the chuck action permission conditions based on the spindle speed signal N. The chuck releasing action is only permitted when the spindle is stationary; when the spindle is not stationary, the chuck releasing action is prohibited to improve operational safety.

[0051] Please see Figure 3 The control unit 70 is configured to perform the following steps by executing a computer program stored internally thereon: The DC bus voltage of the spindle drive assembly 10 and the energy storage voltage of the energy storage assembly 30 are acquired in real time. When the DC bus voltage is found to be higher than the preset braking identification threshold, the spindle is determined to be in regenerative braking state. The regenerative energy recovery component 20 (with the controlled switch outputting a pulse width modulation signal) is controlled to reduce the voltage of the spindle regenerative braking energy of the spindle drive component 10 and transmit it to the energy storage component 30 for charging until the energy storage voltage reaches the preset energy storage upper limit threshold or the spindle braking ends. That is, when the energy storage voltage is detected to reach the preset energy storage upper limit threshold, the regenerative energy recovery component 20 is controlled to stop charging. The duty cycle of the main switch device 22 is adjusted by pulse width modulation to ensure that the charging voltage and charging current of the energy storage component are within the preset range. When a chuck action command signal is received (such as a chuck clamping command or a chuck releasing command), it is determined whether the energy storage voltage is higher than the preset discharge threshold. The preset discharge threshold is determined based on the minimum working bus voltage of the chuck drive device and the energy required for a single action of the electric chuck. If so, disconnect the connection between the external power supply branch component 60 and the chuck drive component 50, and connect the energy storage power supply component 40 and the chuck drive component 50, so that the energy storage component 30 supplies power to the chuck drive component 50 to drive the chuck drive component 50 to perform the corresponding action; If not, the connection between the external power supply branch component 60 and the chuck drive component 50 is made open, and the connection between the energy storage power supply component 40 and the chuck drive component 50 is disconnected. The external power supply branch component 60 (the external power source) supplies power to the chuck drive component 50 to drive the chuck drive component 50 to perform the corresponding action. The control unit 70 acquires the current signal of the chuck motor 52 and determines that the chuck action is complete based on the current signal of the chuck motor 52. Then, it disconnects the connection between the external power supply branch assembly 60 and the chuck drive assembly 50, or disconnects the connection between the energy storage power supply assembly 40 and the chuck drive assembly 50, and returns to the standby monitoring state. Specifically, the control unit 70 determines that the chuck clamping or releasing action is complete based on at least one of the following: the action completion signal fed back by the chuck drive assembly 50, the current change characteristics of the electric chuck motor 52, the action duration, and the position signal. Upon determining that the chuck clamping or releasing action is complete, it cuts off the current power supply path.

[0052] Preferably, it further includes: when it is determined that the spindle stabilization condition and the chuck operation permission condition are met, the chuck drive assembly 50 is allowed to perform a release action, that is, the chuck release action is prohibited when the spindle has not stabilized; and during the chuck operation, the energy storage power supply assembly 40 and the external power supply branch assembly 60 are prohibited from being turned on at the same time, and a protection control signal is output when the energy storage assembly 30 is over-voltage, under-voltage or the power supply branch is over-current.

[0053] Specifically, in this embodiment, after system initialization, V1, V2, N, I, and M code data are collected in real time. If V1 is higher than the threshold, PWM1 is activated to charge the energy storage component at a reduced voltage until V2 reaches its upper limit or braking ends and V1 falls below the threshold. If an M code is received, it is determined whether the spindle has stopped and N=0. If yes, it is determined whether V2 is greater than the threshold; if not, it returns to real-time data collection.

[0054] If V2 is greater than the threshold, PWM2 is started, and the MOSFET of the energy storage power supply device is turned on to supply power to the chuck motor 52. Whether I is greater than the threshold is used to determine whether the chuck action is complete. If yes, the chuck action is considered complete, the MOSFET is turned off, and PWM2 is stopped; otherwise, the chuck motor 52 continues to be powered.

[0055] If V2 is not greater than the threshold, the MOSFET and PWM2 are turned off, KM2 is connected to the contactor coil, and the chuck is connected to an external power supply. The completion of the chuck's operation is determined by whether I is greater than the threshold. If yes, the chuck's operation is considered complete, KM2 disconnects the contactor coil, and the power supply is stopped; otherwise, the chuck motor 52 continues to be powered. The process returns to the main loop and monitoring continues.

[0056] In summary, after the system is powered on and initialized, the control unit 70 acquires the DC bus voltage of the spindle drive assembly 10 and the energy storage voltage of the energy storage assembly 30 in real time. When it is determined that the DC bus voltage is higher than the preset braking identification threshold, it determines that the spindle is in regenerative braking state and controls the regenerative energy recovery assembly 20 to start working, converting the spindle regenerative braking energy into a step-down voltage and transmitting it to the energy storage assembly 30 for charging, until the energy storage voltage reaches the preset energy storage upper limit threshold or the spindle braking ends (the DC bus voltage drops below the threshold), at which point charging stops. When the control unit 70 receives a chuck clamping or releasing action command, it first determines whether the spindle has stopped. If it has not stopped, it prohibits the releasing action. If it has stopped, it further determines whether the current energy storage voltage is higher than the preset discharge threshold. If it is higher, it controls the external power supply branch group. When component 60 is disconnected, the energy storage power supply component 40 is simultaneously turned on. The energy storage component 30, after voltage boosting and stabilization, supplies power to the chuck drive device to drive the chuck motor 52 to perform corresponding actions. If the voltage is too low, the energy storage power supply component 40 is turned off, and the external power supply branch component 60 is turned on. The external power supply then supplies power to the chuck drive device to drive the chuck motor 52 to perform corresponding actions. During chuck operation, charging control of the regenerative energy recovery component and power supply path switching are prohibited simultaneously. The control unit 70 acquires the current signal of the chuck motor 52 in real time during chuck operation. When the current change characteristics determine that the chuck clamping or releasing action has been completed, the power supply path of the current energy storage power supply component 40 or the external power supply branch component 60 is cut off, causing the system to return to standby monitoring state, waiting for the next braking energy recovery or chuck action command. This aims to solve the problems of low utilization rate of spindle braking regenerative energy, difficulty in effectively matching the instantaneous power supply demand of electric chuck action with spindle braking energy, and insufficient reliability and electrical safety of chuck power supply under multi-power supply conditions in the existing technology.

[0057] Compared with existing technologies, the advantages of this method are as follows: 1. To realize the directional transfer of spindle braking regenerative energy to electric chuck action energy, so that the spindle braking energy is directly used for chuck clamping or releasing action after passing through the energy storage component 30, forming a local energy closed loop and improving the local utilization efficiency of regenerative energy; 2. By transferring some of the energy originally dissipated by the braking resistor to the energy storage component, the heating of the braking resistor can be reduced, which helps to reduce the local temperature rise of the machine tool electrical system and improve the thermal stability of the drive device and related control devices; 3. The control unit 70 coordinates the energy recovery and power supply path according to the voltage of the energy storage component 30 and the DC bus voltage. When the energy storage is sufficient, the energy storage component 30 gives priority to supplying power to the chuck drive component 50. When the energy storage is insufficient, it automatically switches to the external power supply branch component 60, thereby ensuring the reliability of the power supply for the chuck operation. 4. An interlocking switching method is adopted between the energy storage power supply component 40 and the external power supply branch component 60 to prevent the two power supplies from being directly connected in parallel to supply power to the chuck drive component 50 at the same time, thereby improving the electrical safety of the system operation; 5. By setting safety control strategies such as spindle stop interlock, overvoltage protection, undervoltage protection, and overcurrent protection, the safety and applicability of system operation can be further improved.

[0058] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A machine tool spindle braking energy recovery system for an electric chuck, characterized in that, include: The system includes a spindle drive assembly, a regenerative energy recovery assembly, an energy storage assembly, an energy storage power supply assembly, a chuck drive assembly, an external power supply branch assembly, and a control unit. The input terminal of the regenerative energy recovery assembly is electrically connected to the DC bus of the spindle drive assembly. The input terminal of the energy storage assembly is electrically connected to the output terminal of the regenerative energy recovery assembly. The power supply terminal of the chuck drive assembly is electrically connected to the output terminal of the energy storage assembly through the energy storage power supply assembly. The output terminal of the external power supply branch assembly is electrically connected to the power supply terminal of the chuck drive assembly. The control unit is electrically connected to the spindle drive assembly, the regenerative energy recovery assembly, the energy storage power supply assembly, the external power supply branch assembly, and the chuck drive assembly. The control unit is configured to perform the following steps by executing a computer program stored internally thereon: The DC bus voltage of the spindle drive assembly and the energy storage voltage of the energy storage assembly are acquired in real time. When the DC bus voltage is found to be higher than the preset braking recognition threshold, the spindle is determined to be in regenerative braking state. The regenerative energy recovery component is controlled to reduce the voltage of the spindle regenerative braking energy of the spindle drive component and transmit it to the energy storage component for charging until the energy storage voltage reaches the preset energy storage upper limit threshold or the spindle braking ends. When a chuck action command signal is received, it is determined whether the energy storage voltage is higher than the preset discharge threshold. If so, disconnect the connection between the external power supply branch component and the chuck drive component, and connect the connection between the energy storage power supply component and the chuck drive component, so that the energy storage component supplies power to the chuck drive component to drive the chuck drive component to perform the corresponding action; If not, connect the external power supply branch component to the chuck drive component and disconnect the energy storage power supply component from the chuck drive component. The external power supply branch component supplies power to the chuck drive component to drive the chuck drive component to perform the corresponding action. The system acquires the chuck motor current signal and determines that the chuck action is complete based on the chuck motor current signal. Then, it disconnects the connection between the external power supply branch component and the chuck drive component, or disconnects the connection between the energy storage power supply component and the chuck drive component, and returns to the standby monitoring state.

2. The machine tool spindle braking energy recovery system for an electric chuck according to claim 1, characterized in that, The spindle drive assembly includes a spindle power supply, a first circuit breaker, a first contactor, a first rectifier, a DC bus, a first inverter, and a spindle motor. The spindle power supply is connected to the input terminal of the first rectifier via the first circuit breaker and the first contactor. The output terminal of the first rectifier is connected to the DC bus. The DC bus is connected to the input terminal of the first inverter. The output terminal of the first inverter is connected to the spindle motor.

3. The machine tool spindle braking energy recovery system for an electric chuck according to claim 1, characterized in that, The regenerative energy recovery component is a Buck converter circuit, including an input filter capacitor, a main switching device, a first inductor, a freewheeling diode, and an output filter capacitor. The control terminal of the main switching device is connected to the control unit. The control unit controls the conduction and cutoff of the main switching device through a pulse width modulation signal. The main switching device is an insulated gate bipolar transistor (IGBT) or a power MOSFET.

4. The machine tool spindle braking energy recovery system for an electric chuck according to claim 1, characterized in that, The energy storage module uses a supercapacitor module, which has a built-in overvoltage protection unit, undervoltage protection unit and single-cell voltage equalization unit.

5. The machine tool spindle braking energy recovery system for an electric chuck according to claim 1, characterized in that, The energy storage power supply component includes a second inductor, a first diode, a first MOSFET, a first capacitor, a fuse, a second MOSFET, and an anti-reverse current diode. The second inductor, the first diode, the first MOSFET, and the first capacitor constitute a boost circuit, which is used to boost the energy storage voltage to the rated operating voltage of the chuck drive component. The anti-reverse current diode is used to suppress the reverse current of the side voltage of the chuck drive component to the energy storage component.

6. The machine tool spindle braking energy recovery system for an electric chuck according to claim 1, characterized in that, The chuck drive assembly includes a second inverter and a chuck motor. The output of the second inverter is connected to the chuck motor. The second inverter is used to convert input electrical energy into AC power required to drive the chuck motor. The chuck motor is used to perform chuck clamping or releasing actions under the drive of the second inverter.

7. The machine tool spindle braking energy recovery system for an electric chuck according to claim 6, characterized in that, The external power supply branch assembly includes a chuck external power supply, a second circuit breaker, a second contactor, and a second rectifier. The chuck external power supply is connected to the input terminal of the second rectifier via the second circuit breaker and the second contactor. The output terminal of the second rectifier is connected to the input terminal of the second inverter.

8. The machine tool spindle braking energy recovery system for an electric chuck according to claim 1, characterized in that, The control unit includes a control module, a first isolation drive circuit, a second isolation drive circuit, and a third isolation drive circuit. The output terminal of the control module is electrically connected to the input terminals of the first isolation drive circuit, the second isolation drive circuit, and the third isolation drive circuit. The output terminal of the first isolation drive circuit is electrically connected to the control terminal of the regenerative energy recovery component. The output terminals of the second isolation drive circuit and the third isolation drive circuit are electrically connected to the control terminal of the energy storage power supply component.

9. The machine tool spindle braking energy recovery system for an electric chuck according to claim 1, characterized in that, Also includes: When the spindle stabilization condition and chuck operation permission condition are met, the chuck drive component is allowed to perform the release action. During the chuck operation, the energy storage power supply component and the external power supply branch component are prohibited from being turned on at the same time. When the energy storage component is over-voltage, under-voltage, or the power supply branch is over-current, a protection control signal is output.

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