Current type variable-speed cordless electric wrench

Abstract

The invention discloses a current type variable-speed cordless electric wrench, and particularly relates to the technical field of electric wrenchs.The current type variable-speed cordless electric wrench comprises a handle, a clutch assembly, a gear assembly and a counter-force arm are sequentially arranged at one end of the handle, a shell is fixed to the other end of the handle, and an electronic assembly is arranged in the shell; the clutch assembly comprises a third-stage gear assembly, a fourth-stage gear assembly and a double-clutch structure which are arranged in a clutch shell and are in transmission connection in sequence. In a high-speed output state, the fourth-stage gear assembly does not participate in torque transmission and does not have a torque amplification effect; in the low-speed state, the fourth-stage gear assembly participates in torque transmission, the output rotating speed is reduced, and the overall reduction ratio participating in torque transmission of the wrench is conveniently changed, so that the output torque of the wrench and the speed of an output shaft are changed, the reduction ratio is automatically switched when the wrench is no-load and loaded, and the tightening efficiency during no-load operation of the wrench is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of electric tools, and in particular to a current-type variable-speed cordless electric wrench. Background Art

[0002] An electric wrench is an electric torque-fixed tool for fixed-torque assembly of threaded fasteners, and is suitable for tightening high-strength bolts. It is widely used in steel structure bridges, plant construction, chemical industry, power generation equipment installation and other fields, as well as occasions with strict requirements on the torque or axial force of bolt fasteners. Among them, the current-type electric wrench is an electric wrench that controls the output torque by monitoring the current signal when the motor is working. Its working principle is based on the relationship between the change in current value and torque value during the tightening process of the motor. When the motor starts working, the current will increase with the increase in load. Through the built-in control system, the current of the motor can be adjusted according to the preset torque value, thereby achieving precise torque control. When the predetermined torque is reached, the motor stops working, thereby completing the tightening operation of the bolt.

[0003] With the rapid development of science and technology, traditional manual tools can no longer meet the tightening needs of large bolts at construction sites, and with the improvement of process requirements, the accuracy requirements for tightening torque are also constantly increasing. A simple current-type electric wrench is affected by the control accuracy, current sampling accuracy and sampling frequency, and the reducer mechanism itself also has a certain impact on the motor output torque efficiency. Based on this, the present invention proposes a current-type variable speed cordless electric wrench. Summary of the invention

[0004] The purpose of the present invention is to provide a current-type variable-speed cordless electric wrench, which can realize automatic switching of the reduction ratio when the wrench is unloaded and loaded, and effectively improve the tightening efficiency when the wrench is unloaded.

[0005] In order to achieve the above-mentioned purpose, the present invention provides the following technical solution: a current-type variable-speed cordless electric wrench, comprising a handle, one end of which is provided with a clutch assembly, a gear assembly and a reaction arm in sequence, and the other end of the handle is fixed with a shell, and an electronic component is arranged in the shell.

[0006] The clutch assembly comprises a third-stage gear assembly, a fourth-stage gear assembly and a dual-clutch structure which are arranged in a clutch housing and are sequentially connected in transmission. A clutch seat and a clutch sleeve are respectively arranged on the outer sides of both ends of the dual-clutch structure. Three steel balls are arranged in the slot in the clutch seat, and a circular groove is arranged on the outer side of the clutch seat. Under high-speed output state, if the vertical torque inside the clutch assembly is less than the critical value, the fourth-stage gear assembly does not participate in torque transmission; At low speed, if the vertical torque inside the clutch assembly is greater than the critical value, the fourth gear assembly will participate in the torque transmission.

[0007] Preferably, the fourth-stage planet carrier of the fourth-stage gear assembly is fixedly connected to the clutch assembly by screws, and a deep groove ball bearing is assembled at the input end of the clutch assembly; In the high-speed output state, the three steel balls are in the slots, and the clutch sleeve is provided with a top-to-top wave spring for pressing the electronic components, so that the three steel balls cannot be lifted up, and the fourth-stage gear assembly does not participate in the transmission and has no torque amplification effect; At low speed, the three steel balls leave the slots and enter the circular slots, the fourth-stage gear assembly participates in torque transmission, and the output speed is reduced.

[0008] Preferably, a motor is provided inside the handle, and a first-stage gear assembly and a second-stage gear assembly are sequentially transmission-connected to the output shaft of the motor, and the second-stage gear assembly is fixedly connected to the third-stage central gear of the third-stage gear assembly.

[0009] Preferably, the gear assembly comprises a fifth-stage gear assembly and a sixth-stage gear assembly which are sequentially arranged in the housing, and the fifth-stage central gear of the fifth-stage gear assembly is transmission-connected to the dual-clutch structure.

[0010] Preferably, one end of the sixth-stage gear assembly away from the fifth-stage gear assembly is connected to an output shaft, the reaction arm is arranged on a side of the housing away from the clutch assembly, and the reaction arm is sleeved on the outside of the output shaft.

[0011] Preferably, a reversing switch is provided on the reaction arm for controlling the rotation direction of the motor, and a start-stop switch is also provided on the handle for providing a start signal and a hysteresis signal for the motor.

[0012] Preferably, the electronic components include a servo controller and a communication board component; a main controller 1 is provided inside the servo controller, and an output end of the main controller 1 is connected to a motor drive module for driving and controlling the motor; the motor is connected to a reducer for amplifying the power provided by the motor to meet the final output torque requirement, and an angle module for controlling the output angle is provided in the reducer, and the angle module is installed directly below the second-stage gear assembly; an input end of the main controller 1 is connected to a current sampling module for collecting the phase current flowing through the motor to improve the output torque accuracy.

[0013] Preferably, the communication board assembly includes a main controller 2, which is connected to the main controller 1 through a serial communication module, and a display screen is provided at the output end of the main controller 2 for displaying relevant content; the main controller 2 is connected to the server through a WIFI module, and the main controller 2 is connected to the matching host computer software through a USB interface, and the final tightening torque result is sent to the server or the host computer software; the communication board assembly is connected to a storage module for storing data, and a button is connected to the input end of the main controller 2.

[0014] Preferably, a lithium battery is provided at the bottom of the handle, and the lithium battery provides power to the wrench through a power management module.

[0015] In the above technical solution, the technical effects and advantages provided by the present invention are: 1. The present invention facilitates the change of the overall reduction ratio involved in the wrench torque transmission through the clutch assembly, thereby changing the wrench output torque and output shaft speed, realizing automatic switching of the reduction ratio when the wrench is unloaded and loaded, and effectively improving the tightening efficiency of the wrench when it is unloaded; 2. The present invention adopts a current and speed dual feedback control structure to improve the output torque accuracy of the wrench; 3. The current-type variable-speed cordless electric wrench of the present invention is an efficient and convenient large-torque output tool, which can be used in the tightening of large bolts. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the overall main structural diagram of the present invention; Figure 2 It is an overall side view of the structure of the present invention; Figure 3 for Figure 2 AA section view; Figure 4 for Figure 3 The local structure diagram of Figure 5 It is a structural diagram of the clutch assembly of the present invention; Figure 6 for Figure 5 BB section view; Figure 7 is a schematic diagram of an electronic component of the present invention; Figure 8 This is the structure diagram of the calibrator.

[0017] Description of reference numerals: 1 reaction arm; 2 gear assembly, 21 housing, 22 fifth stage gear assembly, 23 sixth stage gear assembly, 24 fifth stage central gear, 25 output shaft; 3 clutch assembly, 31 third stage central gear, 32 third stage gear assembly, 33 fourth stage gear assembly, 34 clutch seat, 35 steel ball, 36 double clutch structure, 37 clutch housing, 38 clutch sleeve, 39 slot, 310 circular slot; 4 housing, 5 electronic components, 6 lithium battery, 7 handle, 8 motor, 9 first stage gear assembly, 10 second stage gear assembly, 11 reversing switch, 12 start-stop switch; 13 display, 14 industrial computer, 15 dynamic sensor, 16 bolt simulator, 17 stopper. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0019] The present invention provides Figure 1-6 The current-type variable-speed cordless electric wrench shown in the figure includes a handle 7, a motor 8 is arranged inside the handle 7, a brushed DC motor is selected, and the output shaft of the motor 8 is sequentially connected to a first-stage gear assembly 9 and a second-stage gear assembly 10; a reversing switch 11 is arranged on the reaction arm 1, which is responsible for controlling the rotation direction of the motor 8 (0 is clockwise rotation, 1 is counterclockwise rotation), and a start-stop switch 12 is also arranged on the handle 7, which is used to provide a start signal and a hysteresis signal for the motor 8.

[0020] A clutch assembly 3, a gear assembly 2 and a reaction arm 1 are sequentially arranged at one end of the handle 7. The clutch assembly 3 includes a third-stage gear assembly 32, a fourth-stage gear assembly 33 and a dual-clutch structure 36 which are arranged in a clutch housing 37 and are sequentially connected in transmission. A clutch seat 34 and a clutch sleeve 38 are respectively arranged on the outer sides of both ends of the dual-clutch structure 36. Three steel balls 35 are arranged in the slot 39 in the clutch seat 34. A circular groove 310 is arranged on the outer side of the clutch seat 34. The second-stage gear assembly 10 is fixedly connected to the third-stage center gear 31 of the third-stage gear assembly 32.

[0021] The gear assembly 2 includes a fifth-stage gear assembly 22 and a sixth-stage gear assembly 23 which are sequentially arranged in the housing 21. The fifth-stage central gear 24 of the fifth-stage gear assembly 22 is transmission-connected to the dual-clutch structure 36. The end of the sixth-stage gear assembly 23 away from the fifth-stage gear assembly 22 is connected to the output shaft 25. The reaction arm 1 is arranged on a side of the housing 21 away from the clutch assembly 3, and the reaction arm 1 is sleeved on the outside of the output shaft 25.

[0022] High-speed output state: the three steel balls 35 are in the slots 39, and the clutch sleeve 38 is provided with a top-to-top wave spring that presses the electronic component 5, so that the three steel balls 35 cannot be lifted up. At this time, the transmission of the wrench torque drives the dual clutch structure 36 to rotate through the fourth-stage gear assembly 33. Since the fourth-stage planetary carrier of the fourth-stage gear assembly 33 is fixedly connected with the clutch assembly 3 by screws, and the deep groove ball bearing is assembled at the input end of the clutch assembly 3, the clutch assembly 3 also rotates with the dual clutch structure 36, that is, the fourth-stage planetary carrier is rotating, which is equivalent to the fourth-stage gear assembly 33 not participating in the transmission and having no torque amplification effect; That is, in the high-speed output state, when the vertical torque inside the clutch assembly 3 is less than the critical value, the fourth-stage gear assembly 33 does not participate in the torque transmission, and the total reduction ratio of the torque transmission is small, and the output torque of the wrench is small. However, due to the small total reduction ratio, the output shaft speed of the wrench is faster, and the wrench can quickly complete the no-load pre-tightening operation.

[0023] Low speed state: In the low speed state, as the torque of the wrench increases, when the input torque of the fourth-stage gear assembly 33 is greater than the pre-tightening torque of the mold compression spring of the dual clutch structure 36, the mold compression spring is compressed, and the top wave spring of the clutch sleeve 38 is also compressed. Due to the lack of pressure, the steel ball 35 leaves the slot 39 and enters the circular slot 10. At this time, the clutch assembly 3 rotates as a whole, the fourth-stage gear assembly 33 participates in the torque transmission, and the output speed is reduced; That is, at low speed, when the vertical torque inside the clutch assembly 3 is greater than the critical value, the fourth-stage gear assembly 33 participates in the torque transmission, the total reduction ratio of the torque transmission increases, and the wrench output torque is greater.

[0024] like Figure 1-3 and Figure 7 As shown, a housing 4 is fixed at the other end of the handle 7, and an electronic component 5 is arranged in the housing 4. The electronic component 5 includes a servo controller and a communication board component.

[0025] A main controller 1 is provided inside the servo controller. The output end of the main controller 1 is connected to a motor drive module for driving and controlling the motor 8. The input end of the main controller 1 is connected to a current sampling module for collecting the phase current flowing through the motor 8. The current flows through the sampling resistor to obtain the corresponding voltage value. The analog input channel of the main controller 1 collects the resistor voltage value to indirectly obtain the current size flowing through the motor 8. The output current is roughly linearly related to the output torque of the wrench. The calibrator processes the torque signal and feeds back the result of the real torque output by the wrench. Specifically, the structure of the tester is as follows: Figure 8 As shown, it includes an industrial computer 14, a dynamic sensor 15, and a bolt simulator 16 installed in the tester frame, a wrench is installed on one side of the top of the tester frame, and a stopper 17 is provided on one side of the wrench reaction arm 1, and a display 13 is provided on the top of the tester frame; The torque signal of the dynamic sensor 15 in the calibration instrument is connected to the industrial computer 14, and the industrial computer 14 processes the torque signal and feeds back the result of the wrench outputting the real torque to the display 13, calibrates the corresponding relationship between the current and the torque, and thus the output torque of the wrench can be changed by adjusting the target torque of the display screen in the electronic component 5 below. When the output torque of the output shaft 25 of the wrench is large, the first-stage gear assembly 9, the second-stage gear assembly 10, the third-stage gear assembly 32, the fifth-stage gear assembly 22, and the sixth-stage gear assembly 23 participate in the output torque transmission of the motor 8; when the output torque of the output shaft 25 of the wrench is small, the first-stage gear assembly 9, the second-stage gear assembly 10, the third-stage gear assembly 32, the fourth-stage gear assembly 33, the fifth-stage gear assembly 22, and the sixth-stage gear assembly 23 participate in the output torque transmission of the motor 8, and the overall reduction ratio of the wrench is increased at this time. Under the same output torque of the motor 8, the output torque of the output shaft 25 is greatly improved. The present invention improves the output torque accuracy of the wrench by introducing a current feedback link.

[0026] The motor 8 is also connected to a reducer, which is used to amplify the power provided by the motor 8 to meet the final output torque requirement; an angle module for controlling the output angle is provided in the reducer, and the angle module is installed directly below the second-stage gear assembly 10. The gear sensor is a dedicated chip for automotive-grade speed measurement, MT36xx, as the angle module. As the gear rotates, the chips sense the increase and decrease of the magnetic flux density. When the magnetic flux density increases and exceeds the predefined hysteresis level, the output is turned on (low level); when the magnetic flux density decreases and exceeds the hysteresis level, the output is turned off (output high level). When the gear rotates one circle, the angle module outputs three pulses, and the main controller collects the angle pulse signal, combines the wrench output torque judgment condition, and finally converts the angle signal into the angle of the bolt tightened by the wrench. By introducing a speed feedback link, the present invention can clearly know the operating state of the motor 8, adjust the Pwm output duty cycle of the motor 8, and make the motor 8 basically close to the stall state in the final loading stage, thereby ensuring that the output torque of the motor 8 greatly improves the wrench control accuracy.

[0027] The communication board assembly includes a main controller 2, which is connected to the main controller 1 through a serial communication module. A display screen is provided at the output end of the main controller 2, and a 1.3-inch display screen is selected to display relevant content. The main controller 2 is connected to the server through a WIFI module, and the main controller 2 is connected to the matching host computer software through a USB interface. The final tightening torque result of the wrench is sent to the server or the matching host computer software. At the same time, the display screen in the electronic assembly 1 can display the current wrench status, output torque, direction of wrench operation, and operating status of the motor 8.

[0028] The communication board assembly is connected to a 128Mb Flash storage module for storing data, which is responsible for storing the operating parameter data of the motor 8, the current calibration data of the wrench, and the tightening result data of the wrench. The host computer software can view the tightening result data of the wrench by connecting the USB cable to the USB interface on the wrench.

[0029] The input end of the main controller 2 is connected with a button, which is convenient for adjusting the target torque of the display screen in the above-mentioned electronic component 5 to change the output torque of the wrench and improve the work efficiency of the workers.

[0030] A lithium battery 6 is provided at the bottom of the handle 7. The lithium battery 6 provides power to the wrench through a power management module. The power management module provides various power requirements for electronic components (communication board components, servo controllers, start / stop, reversing components, and display screens).

Claims

1. A current-type variable speed cordless electric wrench, comprising a handle (7), characterized in that: A clutch assembly (3), a gear assembly (2) and a reaction arm (1) are sequentially arranged at one end of the handle (7), and a housing (4) is fixed to the other end of the handle (7), wherein an electronic assembly (5) is arranged inside the housing (4); The clutch assembly (3) comprises a third-stage gear assembly (32), a fourth-stage gear assembly (33) and a dual clutch structure (36) which are arranged in a clutch housing (37) and are sequentially connected in transmission, a clutch seat (34) and a clutch sleeve (38) are respectively arranged on the outer sides of both ends of the dual clutch structure (36), three steel balls (35) are arranged in a slot (39) in the clutch seat (34), and a circular slot (310) is arranged on the outer side of the clutch seat (34); In the high-speed output state, the vertical torque applied to the clutch assembly (3) is less than a critical value, and the fourth-stage gear assembly (33) does not participate in the torque transmission; In the low-speed state, if the vertical torque applied to the interior of the clutch assembly (3) is greater than a critical value, the fourth-stage gear assembly (33) participates in the torque transmission.

2. The current-type variable-speed cordless electric wrench according to claim 1, characterized in that: The fourth-stage planet carrier of the fourth-stage gear assembly (33) is fixedly connected to the clutch assembly (3) by means of screws, and a deep groove ball bearing is assembled at the input end of the clutch assembly (3); In the high-speed output state, the three steel balls (35) are in the slots (39), and a top-to-top wave spring for pressing the electronic component (5) is provided in the clutch sleeve (38), so that the three steel balls (35) cannot be lifted up, and the fourth-stage gear component (33) does not participate in the transmission and has no torque amplification effect; In the low speed state, the three steel balls (35) leave the slot (39) and enter the circular slot (310), the fourth-stage gear assembly (33) participates in the torque transmission, and the output speed is reduced.

3. The current-type variable-speed cordless electric wrench according to claim 1, characterized in that: A motor (8) is provided inside the handle (7); a first-stage gear assembly (9) and a second-stage gear assembly (10) are sequentially connected in transmission to an output shaft of the motor (8); and the second-stage gear assembly (10) is fixedly connected to a third-stage central gear (31) of a third-stage gear assembly (32).

4. The current-type variable-speed cordless electric wrench according to claim 1, characterized in that: The gear assembly (2) comprises a fifth-stage gear assembly (22) and a sixth-stage gear assembly (23) which are sequentially arranged in the housing (21); the fifth-stage central gear (24) of the fifth-stage gear assembly (22) is transmission-connected to the dual-clutch structure (36).

5. The current-type variable-speed cordless electric wrench according to claim 4, characterized in that: An end of the sixth-stage gear assembly (23) away from the fifth-stage gear assembly (22) is connected to an output shaft (25), and the reaction arm (1) is arranged on a side of the housing (21) away from the clutch assembly (3), and the reaction arm (1) is sleeved on the outside of the output shaft (25).

6. The current-type variable-speed cordless electric wrench according to claim 3, characterized in that: The reaction arm (1) is provided with a reversing switch (11) for controlling the rotation direction of the motor (8), and the handle (7) is also provided with a start-stop switch (12) for providing a start signal and a hysteresis signal for the motor (8).

7. The current-type variable-speed cordless electric wrench according to claim 3, characterized in that: The electronic component (5) includes a servo controller and a communication board component; A main controller 1 is provided inside the servo controller, and an output end of the main controller 1 is connected to a motor drive module for driving and controlling the motor (8); The motor (8) is connected to a reducer for amplifying the power provided by the motor (8) to meet the final output torque requirement, and an angle module for controlling the output angle is provided in the reducer, and the angle module is installed directly below the second-stage gear assembly (10); An input end of the main controller is connected to a current sampling module for collecting phase current flowing through the motor (8) to improve the output torque accuracy.

8. The current-type variable-speed cordless electric wrench according to claim 7, characterized in that: The communication board assembly includes a main controller 2, which is connected to the main controller 1 via a serial communication module, and an output end of the main controller 2 is provided with a display screen for displaying relevant content; The main controller 2 is connected to the server via a WIFI module, and the main controller 2 is connected to the matching host computer software via a USB interface, and the final tightening torque result is sent to the server or the host computer software; The communication board component is connected with a storage module for storing data, and the input end of the main controller 2 is connected with a button.

9. The current-type variable-speed cordless electric wrench according to claim 1, characterized in that: A lithium battery (6) is provided at the bottom of the handle (7), and the lithium battery (6) provides electrical energy to the wrench via a power management module.

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