Electric wrench with precise control of torque output and delay timer for electric wrench

Abstract

The application discloses an electric wrench with precise control of torque output and a time delay device of the electric wrench, comprising a machine body, a controller and a rotary drive mechanism arranged in the machine body, and a time delay device arranged on the machine body, wherein the time delay device comprises an input part, a buffer disc, an output part and a time delay torsional spring, the buffer disc is arranged between the input part and the output part, a convex block movable space one is arranged on the buffer disc / input part, a limiting convex block one is arranged on the input part / buffer disc, the limiting convex block one is movably arranged in a limiting long slot one to limit the relative rotation angle, a convex block movable space two is arranged on the buffer disc / output part, a limiting convex block two is arranged on the output part / buffer disc, the limiting convex block two is movably arranged in a limiting long slot two to limit the relative rotation angle, and the two ends of the time delay torsional spring are connected with the input part and the output part respectively, the time delay device makes the wrench have a time delay time before the torque reaches the set value, buffers the time of the wrench and improves the precision of the control of the torque output.

Description

TECHNICAL FIELD

[0001] The present application relates to an electric wrench, in particular to an electric wrench capable of precisely controlling the output of torque and a delay device of the electric wrench. BACKGROUND

[0002] The electric wrench refers to an electric tool for tightening and loosening bolts and nuts, and is a tool for tightening high-strength bolts. The electric wrench is used for the installation of steel structure bridges, factory buildings, chemical and power generation equipment, the initial tightening, final tightening of high-strength bolt construction of large hexagonal head high-strength bolts, and the initial tightening of torsional shear type high-strength bolts, as well as occasions with strict requirements on the torque or axial force of bolt fasteners. In the process of using the electric wrench, the nut or screw is first sleeved or inserted into the inside of the screw, and then twisted, so as to loosen or tighten.

[0003] For example, the patent CN203031526U includes a T-shaped machine shell and a power supply assembly connected to the bottom of the machine shell. The horizontal cavity of the machine shell is provided with a motor, a motor gear connected to the shaft of the motor, a gear box engaged with the motor gear, an impact assembly, and an output shaft. A switch lever connected to the motor is installed on the machine shell, and a switch connected to the switch lever is also installed on the machine shell. A power socket is provided at the bottom of the machine shell and is connected to the switch. The shaft of the motor is connected to one end of the output shaft through the impact assembly. The output shaft is used to connect the wrench sleeve. When the shaft of the motor rotates, the rotating power of the motor is transmitted to the impact assembly through the gear box, and then the impact assembly drives the output shaft to rotate, so that the handle sleeve outputs the rotating torque to tighten or loosen the screw.

[0004] When the electric wrench is used to tighten or loosen the bolt, the output torque of the output shaft of the electric wrench is generally controlled to reach the set torque value for tightening or loosening operation. The electric wrench is provided with a controller to monitor the current of the motor. The controller can calculate the output torque according to the motor curve through the detected current. When the controller detects that the current changes to the current value under the condition of the set torque value, the controller controls the motor brake to stop, so as to control the output shaft of the electric wrench to output the set torque value.

[0005] The conventional electric wrench controls the output shaft output torque to reach the set torque value, and a very precise high-sensitivity circuit system is required to control the output torque of the electric wrench. When the electric wrench is screwing a bolt, the torque output by the electric wrench is continuously increasing from the moment when the threads of the bolt and the nut are close to the moment when the bolt is completely locked. When the torque increases to the set torque, the controller controls the motor to stop to achieve the control of the final output torque value of the electric wrench. However, the time from the moment when the threads of the bolt and the nut are close to the moment when the bolt is completely locked is very short. When the existing conventional electric wrench reaches the set torque, the controller receives a signal to control the motor to stop. From the moment when the motor receives the brake signal to the moment when the motor completely stops, the motor directly enters the brake state from the full-speed state. The motor continues to run for a period of time due to inertia. The brake effect of the motor is not controlled due to the influence of the running inertia. The running for this period of time will cause the output torque tolerance of the wrench to be large, and the torque value of the wrench when it stops finally has great uncertainty, and the size of the final stop torque value of the electric wrench cannot be accurately controlled. SUMMARY

[0006] Based on the problem that the size of the final stop torque value of the electric wrench cannot be accurately controlled, the present application provides an electric wrench for accurately controlling torque output and a delay timer of the electric wrench.

[0007] The technical scheme adopted by the present application to solve the above technical problems is as follows: an electric wrench for accurately controlling torque output, comprising a machine body, a controller and a rotary drive mechanism arranged in the machine body, the rotary drive mechanism comprising a transmission shaft for transmitting rotary power, the controller being electrically connected with the rotary drive mechanism, and a current sensing sub-module being arranged in the controller for detecting the current when the rotary drive mechanism is working, characterized in that a delay timer is arranged on the machine body, the delay timer comprising an input member, a buffer disc, an output member and a delay torsional spring, the input member, the buffer disc and the output member rotating around the same axis, the input member being connected with the transmission shaft and being able to be driven to rotate by the transmission shaft, an output shaft for outputting torque being arranged on the output member, the buffer disc being arranged between the input member and the output member for linkage connection of the input member and the output member, a protrusion activity space one being arranged on the buffer disc / input member, a limiting protrusion one being arranged on the input member / buffer disc, the limiting protrusion one being movably arranged in the protrusion activity space one to limit the rotation angle of the input member relative to the buffer disc, a protrusion activity space two being arranged on the buffer disc / output member, a limiting protrusion two being arranged on the output member / buffer disc, the limiting protrusion two being movably arranged in the protrusion activity space two to limit the rotation angle of the output member relative to the buffer disc, and the delay torsional spring being arranged between the input member and the output member, and the two ends of the delay torsional spring being connected with the input member and the output member respectively, the delay timer having the following states when the transmission shaft rotates forward or reversely:

[0008] The first state is that the output shaft is not loaded, the input part and the output part rotate synchronously, and the power is transmitted between the input part and the output part only through the time-delay torsion spring.

[0009] The second state is that the output shaft is loaded, the input part and the output part rotate relatively to make the time-delay torsion spring torsionally deformed, and the power is transmitted between the input part and the output part only through the time-delay torsion spring.

[0010] The third state is that the output shaft is loaded more than a certain load, the limiting block one and one end of the block movable space one abut, the limiting block two and one end of the block movable space two abut, so that the input part and the output part rotate synchronously, the time-delay torsion spring reaches the maximum torsion angle, and the power is transmitted between the input part and the output part only through the buffer disc.

[0011] When the time-delay device is in the second state, the controller senses the current change and controls the rotary driving mechanism to slow down, and when the controller detects that the torsion force output by the output shaft reaches the set torsion force in the third state, the controller controls the rotary driving mechanism to stop rotating.

[0012] The further preferred technical scheme of the present application is that the maximum torsion angle of the time-delay torsion spring is the same when the transmission shaft rotates forward and reversely.

[0013] The further preferred technical scheme of the present application is that the maximum torsion angle of the time-delay torsion spring is not more than plus or minus 120°, and the maximum torsion angle of the time-delay torsion spring is not less than plus or minus 45°.

[0014] The further preferred technical scheme of the present application is that the time-delay device further comprises an outer sleeve, the input part, the buffer disc, the output part and the time-delay torsion spring are arranged in the outer sleeve, the output shaft extends from the front end of the outer sleeve and is used for outputting the torsion force, the outer sleeve is detachably connected to the front end of the machine body, the rear end of the input part is provided with a socket, the transmission shaft extends from the front end of the machine body and is inserted into the socket and is in driving connection with the input part.

[0015] The further preferred technical scheme of the present application is that two limiting blocks three are arranged on the end face of one end of the buffer disc / input part, the two limiting blocks three surround to form the block movable space one for the limiting block one to be inserted and moved, two limiting blocks four are arranged on the end face of one end of the buffer disc / output part, and the two limiting blocks four surround to form the block movable space two for the limiting block two to be inserted and moved.

[0016] The further preferred technical scheme of the present application is that the outer sleeve is internally provided with channels for placing the input member, the buffer disc, the output member and the delay torsional spring, the end face of the input member facing the buffer disc is protrudingly provided with two symmetrically arranged limiting protrusions three, the end portions of the two limiting protrusions three form the protrusion movable space one, the side of the buffer disc facing the input member is provided with the limiting protrusion one corresponding to the protrusion movable space one, the end face of the output member facing the buffer disc is protrudingly provided with two symmetrically arranged limiting protrusions four, the end portions of the two limiting protrusions four form the protrusion movable space two, the side of the buffer disc facing the output member is provided with the limiting protrusion two corresponding to the protrusion movable space two, the inner side face of the limiting protrusion three is a circular arc face, the inner side faces of the two limiting protrusions three enclose to form the shaft connecting space one, the inner side face of the limiting protrusion four is a circular arc face, the inner side faces of the two limiting protrusions four enclose to form the shaft connecting space two, the support shaft is inserted in the center of the buffer disc, and the two ends of the support shaft are respectively inserted in the shaft connecting space one and the shaft connecting space two, so that the input member, the buffer disc and the output member are connected on the same shaft to rotate, and the delay torsional spring is sleeved on the outside of the buffer disc.

[0017] The further preferred technical scheme of the present application is that the rear end of the outer sleeve is provided with the socket for inserting the front end of the machine body, the side wall of the front end of the machine body is provided with the annular step, the outer sleeve is provided with the screw hole, the front end of the machine body is provided with the threaded hole corresponding to the screw hole, when the front end of the machine body is inserted into the socket, the rear end of the outer sleeve abuts against the annular step, and the outer sleeve and the machine body are fixed through the screw.

[0018] The further preferred technical scheme of the present application is that the first current preset value is set in the controller, the first current preset value corresponds to the working current when the output shaft is loaded and the delay torsional spring starts to be twisted and deformed, when the controller detects that the working current reaches the first current preset value, the controller controls the rotary driving mechanism to slow down.

[0019] The further preferred technical scheme of the present application is that the second current preset value is set in the controller, the second current preset value corresponds to the working current when the output shaft outputs the set torsion, when the controller detects that the working current reaches the second current preset value, the controller controls the rotary driving mechanism to stop rotating.

[0020] Another subject: the delay timer of the electric wrench, characterized by comprising a shell, an input, a buffer disc, an output and a delay torsional spring are arranged in the shell, the input, the buffer disc and the output are limited to rotate around the same axis in the shell, the input is used to receive the rotary power, the output is provided with an output shaft for outputting the torsion, the buffer disc is arranged between the input and the output for linkage connection of the input and the output, the buffer disc / input is provided with a convex block activity space one, the input / buffer disc is provided with a limiting convex block one, the limiting convex block one is movably arranged in the convex block activity space one to limit the angle of rotation of the input relative to the buffer disc, the buffer disc / output is provided with a convex block activity space two, the output / buffer disc is provided with a limiting convex block two, the limiting convex block two is movably arranged in the convex block activity space two to limit the angle of rotation of the output relative to the buffer disc, the delay torsional spring is arranged between the input and the output, and the two ends of the delay torsional spring are connected with the input and the output respectively, the input receives the power in the positive direction or the reverse direction, and the delay timer has the following states:

[0021] The first state, the output shaft has no load holding, the input and the output rotate synchronously, and the input and the output only transmit power through the delay torsional spring in this state;

[0022] The second state, the output shaft has load holding, the input and the output rotate relatively to make the delay torsional spring torsion deformation, and the input and the output only transmit power through the delay torsional spring in this state;

[0023] The third state, the load of the output shaft is greater than a certain load, the limiting convex block one abuts against one end of the convex block activity space one, and the limiting convex block two abuts against one end of the convex block activity space two, so that the input and the output rotate synchronously, the delay torsional spring reaches the maximum torsion angle, and the input and the output only transmit power through the buffer disc in this state.

[0024] Compared with the prior art, the advantages of the present application are that a time delay device is additionally provided, and the time delay device has the following states when the transmission shaft rotates forward or reversely. In a first state, the output shaft has no load holding, the input member and the output member rotate synchronously, and power is only transmitted between the input member and the output member through the time delay torsional spring; in a second state, the output shaft has load holding, the input member and the output member rotate relatively to make the time delay torsional spring torsionally deform, and power is only transmitted between the input member and the output member through the time delay torsional spring; and in a third state, the load of the output shaft is greater than a certain load, the limiting protrusion one abuts against one end of the protrusion movable space one, the limiting protrusion two abuts against one end of the protrusion movable space two, so that the input member and the output member rotate synchronously, and the time delay torsional spring reaches the maximum torsional angle, and power is only transmitted between the input member and the output member through the buffer disc. When the time delay device is in the second state, the controller controls the rotary driving mechanism to slow down, and when the time delay device is in the third state, the controller controls the rotary driving mechanism to stop rotating when the controller detects that the torsion force output by the output shaft reaches the set torsion force through the current. When the electric wrench is operated, the second state of the time delay device is used to realize the buffer delay, so that the wrench has an additional delay time before the torsion force reaches the set value, and in this delay time, the controller controls the transmission shaft of the rotary driving mechanism to slow down, so that the controller has more time to reduce the rotation speed of the rotary driving mechanism, and when the controller senses that the torsion force output by the output shaft reaches the set value through the monitoring of the current change, the rotation speed has been reduced to a very slow state, and the controller can control the electric wrench to stop immediately, so that the brake is basically negligible due to the running inertia, the time node at which the electric wrench stops running is controllable, that is, the torsion force output end point is controllable, the delay provides the wrench with a buffer time to improve the control precision of the torsion force output, and the electric wrench can more accurately control the output torsion force. BRIEF DESCRIPTION OF DRAWINGS

[0025] The application will be described in further detail below with reference to the drawings and preferred embodiments, but those skilled in the art will appreciate that the drawings are only drawn for the purpose of explaining the preferred embodiments and therefore should not be regarded as limiting the scope of the application. In addition, unless specifically indicated, the drawings only schematically show the composition or structure of the described objects and can include exaggerated displays, and the drawings are not necessarily drawn to scale.

[0026] Figure 1 It is a schematic diagram of the overall structure of the electric wrench;

[0027] Figure 2 It is a split diagram of the time delay device and the machine body;

[0028] Figure 3 It is a schematic diagram of the three-dimensional structure of the time delay device Figure 1 ;

[0029] Figure 4 It is a schematic diagram of the three-dimensional structure of the time delay device Figure 2 ;

[0030] Figure 5 is a cutaway view of the time delay device;

[0031] Figure 6 is an exploded view of the time delay device;

[0032] Figure 7 is an exploded view of the time delay device;

[0033] Figure 8 is a coupling view of the input, buffer disk and output;

[0034] Figure 9 is a cutaway view of the first limit block and the first block space;

[0035] Figure 10 is a cutaway view of the second limit block and the second block space;

[0036] Figure 11 is a torque control curve of the wrench;

[0037] Figure 12 is a view of the time delay device in the first state;

[0038] Figure 13 is a view of the time delay device in the second state;

[0039] Figure 14 is a view of the time delay device in the third state.

[0040] In the drawings: 1, body; 2, time delay device; 3, sleeve body; 4, screw; 5, screw hole; 6, socket; 7, threaded hole; 8, annular step; 9, transmission shaft; 10, output shaft; 11, opening two; 12, input; 13, insertion hole; 14, bearing; 15, bearing installation slot; 16, output; 17, outer ring edge; 18, buffer disk; 19, time delay torsion spring; 20, support shaft; 21, channel; 22, first limit block; 23, second limit block; 25, fourth limit block; 26, second block space; 27, third limit block; 28, first block space; 29, first shaft connection space; 30, second shaft connection space. DETAILED DESCRIPTION

[0041] The preferred embodiments of the present application will be described in detail below with reference to the attached drawings. Those skilled in the art will appreciate that the description herein is by way of example only and is not to be construed in any way to limit the scope of the present application.

[0042] It should be noted that like numbers refer to like elements throughout the several views of the drawings and as such, once an element is defined in one drawing that element is contained in subsequent drawings incorporating the drawing containing the definition of the element and further definitions and explanations of the element can not be provided in subsequent drawings.

[0043] Figures 1-14 As shown in the figure, the electric wrench comprises a body 1, a controller and a rotary drive mechanism are arranged in the body 1, the rotary drive mechanism comprises a transmission shaft 9 for transmitting rotary power, the controller is electrically connected with the rotary drive mechanism.

[0044] The rotary drive mechanism is a conventional mechanism for outputting rotary power, for example, preferably, the rotary drive mechanism comprises a motor and a speed reduction gear box, a motor shaft of the motor is connected with the speed reduction gear box, an output end of the speed reduction gear box is provided with the transmission shaft 9, the speed reduction gear box receives the rotary power of the motor shaft of the motor and outputs through the transmission shaft 9, the controller is electrically connected with the motor, and a current induction sub-module is arranged in the controller for detecting the current of the motor during operation.

[0045] The controller can detect the working current of the motor, and then calculate the output torque under the working current according to the motor characteristic curve, and the output torque under different working currents of the motor is different.

[0046] Figure 1 、 Figure 5 、 Figure 6 、 Figure 7 As shown in the figure, the body 1 is provided with a time delay device 2, the time delay device 2 comprises an input member 12, a buffer disc 18, an output member 16 and a time delay torsional spring 19, the input member 12, the buffer disc 18 and the output member 16 rotate around the same axis.

[0047] Figure 1 、 Figure 2 As shown in the figure, preferably, the time delay device 2 further comprises a sleeve body 3, the input member 12, the buffer disc 18, the output member 16 and the time delay torsional spring 19 are arranged in the sleeve body 3, the sleeve body 3 is provided with a channel 21 for arranging the input member 12, the buffer disc 18, the output member 16 and the time delay torsional spring 19, the input member 12, the buffer disc 18 and the output member 16 are limited to rotate around the same axis in the sleeve body 3, and the sleeve body 3 is detachably connected to the front end of the body 1.

[0048] Specifically, the rear end of the sleeve body 3 is provided with a socket 6 for inserting the front end of the body 1 into the channel 21, the sidewall of the front end of the body 1 is provided with an annular step 8, the sleeve body 3 is provided with a screw hole 5, and the front end of the body 1 is provided with a threaded hole 7 corresponding to the screw hole 5, when the front end of the body 1 is inserted into the socket 6, the rear end of the sleeve body 3 abuts against the annular step 8, and the sleeve body 3 and the body 1 are fixed through a screw 4. Preferably, the circumferential sidewall of the sleeve body 3 is provided with four uniformly distributed screw holes 5, the sidewall of the front end of the body 1 is provided with four threaded holes 7 corresponding to the four screw holes 5 respectively, when the rear end of the sleeve body 3 is sleeved on the front end of the body 1, the screw 4 is connected by penetrating through the screw hole 5 and the threaded hole 7, so as to detachably fix the sleeve body 3 on the front end of the body 1.

[0049] Figure 4As shown, the input member 12 is connected with the transmission shaft 9 and can be driven to rotate by the transmission shaft 9. The front end of the body 1 is provided with an opening one, the transmission shaft 9 extends out of the body 1 from the opening one, and the rear end of the input member 12 is provided with a socket 13 which is plugged with the transmission shaft 9. When the time delay device 2 is installed on the body 1, the transmission shaft 9 extending out of the front end of the body 1 is inserted into the socket 13 and is in transmission connection with the output member 16. When the motor is started, the transmission shaft 9 rotates and drives the input member 12 to rotate coaxially. Preferably, the transmission shaft 9 is a square shaft, and the socket 13 is a square hole which is matched with the transmission shaft 9.

[0050] Figure 3 As shown, the output member 16 is provided with an output shaft 10 for outputting torque, and the output shaft 10 extends out of the front end of the sleeve body 3 for outputting torque. The front end of the sleeve body 3 is provided with an opening two 11 for the output shaft 10 to extend out. The output shaft 10 is used for installing a wrench sleeve or other tool head. In addition, the time delay device 2 can be directly connected with the wrench sleeve through the transmission shaft 9 when it is detached from the body 1.

[0051] Figures 5-10 As shown, the buffer disc 18 is arranged between the input member 12 and the output member 16 for linkage connection of the input member 12 and the output member 16.

[0052] The buffer disc 18 / input member 12 is provided with a protrusion activity space one 28, and the input member 12 / buffer disc 18 is provided with a limiting protrusion one 22 which is movably arranged in the protrusion activity space one 28 to limit the angle of rotation of the input member 12 relative to the buffer disc 18.

[0053] The protrusion activity space one 28 can be a movable groove arranged on the buffer disc 18 / input member 12.

[0054] For example, in the present patent, preferably, the end face of one end of the buffer disc 18 / input member 12 is provided with two limiting protrusions three 27 which enclose to form the protrusion activity space one 28 for the limiting protrusion one 22 to insert and move.

[0055] Most preferably, the end face of one end of the input member 12 facing the buffer disc 18 is provided with two symmetrically arranged limiting protrusions three 27, and the end portions of the two limiting protrusions three 27 form the protrusion activity space one 28. The side of the buffer disc 18 facing the input member 12 is provided with the limiting protrusion one 22 which corresponds to the protrusion activity space one 28. The limiting protrusion one 22 is inserted into the protrusion activity space one 28, so that in the process of rotation of the input member 12 relative to the buffer disc 18, the limiting protrusion one 22 can move between the two limiting protrusions three 27.

[0056] When the input member 12 rotates forward relative to the buffer disc 18, the limiting protrusion one 22 slides along the protrusion active space one 28 to one end until the limiting protrusion three 27 at the one end of the protrusion active space one 28 rotates to contact the limiting protrusion one 22, at which time the input member 12 can push the limiting protrusion one 22 through the limiting protrusion three 27 to make the buffer disc 18 and the input member 12 rotate forward synchronously; when the input member 12 rotates reversely relative to the buffer disc 18, the limiting protrusion one 22 slides along the protrusion active space one 28 to the other end until the limiting protrusion three 27 at the other end of the protrusion active space one 28 rotates to contact the limiting protrusion one 22, at which time the input member 12 can push the limiting protrusion one 22 through the limiting protrusion three 27 to make the buffer disc 18 and the input member 12 rotate reversely synchronously. Thus, the input member 12 and the buffer disc 18 can only rotate relative to each other by a certain angle.

[0057] The buffer disc 18 / output member 16 is provided with a protrusion active space two 26, and the output member 16 / buffer disc 18 is provided with a limiting protrusion two 23, which is movably arranged in the protrusion active space two 26 to limit the angle of rotation of the output member 16 relative to the buffer disc 18.

[0058] The protrusion active space two 26 can be an active slot arranged on the buffer disc 18 / output member 16.

[0059] For example, the patent, preferably, the end face of one end of the buffer disc 18 / output member 16 is provided with two limiting protrusions four 25, and the two limiting protrusions four 25 form a protrusion active space two 26 between them for the limiting protrusion two 23 to insert and move.

[0060] Most preferably, the end face of one end of the output member 16 facing the buffer disc 18 is provided with two symmetrically arranged limiting protrusions four 25, and the two limiting protrusions four 25 form a protrusion active space two 26 between the end portions thereof, and the side of the buffer disc 18 facing the output member 16 is provided with a limiting protrusion two 23 corresponding to the protrusion active space two 26, and the limiting protrusion two 23 is inserted into the protrusion active space two 26, so that during the rotation of the buffer disc 18 relative to the output member 16, the limiting protrusion two 23 can move between the two limiting protrusions four 25.

[0061] When the buffer disc 18 is pushed by the output member 16 to rotate synchronously forward, the limiting block two 23 slides along the block active space two 26 to the positive end until the limiting block two 23 rotates to contact the limiting block four 25 at the positive end of the block active space two 26, at this time the buffer disc 18 can push the limiting block four 25 through the limiting block two 23, so that the output member 16, the buffer disc 18 and the input member 12 rotate synchronously forward, at this time the buffer disc 18 is used to transmit the power of the input member 12 to the output member 16 to drive the output member 16 to rotate; when the buffer disc 18 is pushed by the input member 12 to rotate synchronously reverse, the limiting block two 23 slides along the block active space two 26 to the reverse end until the limiting block two 23 rotates to contact the limiting block four 25 at the reverse end of the block active space two 26, at this time the buffer disc 18 can push the limiting block four 25 at the end through the limiting block two 23, so that the input member 12, the buffer disc 18 and the output member 16 rotate synchronously reverse, so that the buffer disc 18 is used to transmit the power of the input member 12 to the output member 16 to drive the output member 16 to rotate. The cooperation of the limiting block two 23 and the block active space two 26 makes the output member 16 and the buffer disc 18 only relatively rotate within a certain angle.

[0062] The input member 12 and the output member 16 are connected by the buffer disc 18, so that the input member 12 and the output member 16 can relatively rotate within a certain angle range, when the relative rotation reaches the maximum angle range value, the input member 12 can drive the output member 16 to rotate synchronously through the buffer disc 18.

[0063] The delay torsion spring 19 is arranged between the input member 12 and the output member 16, and the two ends of the delay torsion spring 19 are respectively connected to the input member 12 and the output member 16.

[0064] When the transmission shaft 9 rotates forward or reversely, the delay timer 2 has the following states:

[0065] Figure 12 As shown, the first state, the output shaft 10 has no load holding, at this time the output shaft 10 idles, the input member 12 and the output member 16 rotate synchronously, in this state, the input member 12 and the output member 16 only transmit power through the delay torsion spring 19, in this process, the input member 12 and the output member 16 only transmit torsion through the delay torsion spring 19;

[0066] Figure 13 As shown, the second state, the output shaft 10 has load holding, the input member 12 and the output member 16 relatively rotate to make the delay torsion spring 19 torsionally deform, in this state, the input member 12 and the output member 16 only transmit power through the delay torsion spring 19, in this process, the input member 12 and the output member 16 only transmit torsion through the delay torsion spring 19;

[0067] Figure 14As shown, in the third state, the load of the output shaft 10 is greater than a certain load, at this time, the limiting block one 22 abuts against the limiting block three 27 at one end of the block active space one 28, and the limiting block two 23 abuts against the limiting block four 25 at one end of the block active space two 26, so that the input member 12 is synchronously rotated by the buffer disc 18 pushing the output member 16 in the rotation process, at this time, the delay torsional spring 19 reaches the maximum torsion angle, in this state, the power is only transmitted between the input member 12 and the output member 16 through the buffer disc 18, and in the process of the input member 12 pushing the output member 16 synchronously rotating through the buffer disc 18, the buffer disc 18 and the delay torsional spring 19 jointly transmit the torsion, since the torsion angle of the delay torsional spring 19 does not change in this process, the torsion value transmitted by the delay torsional spring 19 is a constant value, and the additional torsion is transmitted through the buffer disc 18.

[0068] When the delay timer 2 is in the second state, the controller senses the current change and controls the rotary drive mechanism to decelerate, and when in the third state, the controller detects through the current that the torsion output by the output shaft 10 reaches the set torsion, and controls the rotary drive mechanism to stop rotating.

[0069] When the electric wrench is working, the buffer delay is realized through the second state of the delay timer 2, so that the wrench has a delay time before the torsion reaches the set value, in which delay time, the controller controls the transmission shaft 9 of the rotary drive mechanism to decelerate, giving the controller more time to reduce the rotation speed of the rotary drive mechanism, when the controller senses through the current change that the torsion output by the output shaft 10 reaches the set value, the rotation speed has been reduced to a very slow state, and the controller can control the electric wrench to stop rotating immediately, so that the brake is basically negligible due to the running inertia, and the time node at which the electric wrench stops running is controllable, i.e., the torsion output end point is controllable, this delay gives the wrench a buffer time to improve the precision of controlling the torsion output, so that the electric wrench can more accurately control the output torsion.

[0070] Preferably, the maximum torsion angle of the delay torsion spring 19 is the same when the transmission shaft 9 rotates forward and reversely, that is, the maximum angle of the input member 12 rotating relative to the output member 16 is the same when the transmission shaft 9 rotates forward and reversely. Preferably, the limit block one 22 and the limit block two 23 are the same in structure and symmetrically arranged on both sides of the buffer disc 18, and the two ends of the block activity space one 28 on the input member 12 are aligned with the two ends of the block activity space two 26 on the output member 16. In the first state, the input member 12 drives the output member 16 to rotate synchronously through the delay torsion spring 19, and the limit block one 22 abuts against one end of the block activity space one 28 and the limit block two 23 abuts against one end of the block activity space two 26 during the rotation. In the second state, the output shaft 10 has a load holding, and in this process, the input member 12 starts to rotate relative to the output member 16. The input member 12 drives the limit block one 22 to move the buffer disc 18 to rotate relative to the output member 16 through the limit block three 27, and the limit block two 23 on the buffer disc 18 rotates in the block activity space two 26 from one end to the other end. When the limit block two 23 rotates to contact the limit block four 25 on the other end, the delay timer 2 reaches the third state, and the input member 12 starts to drive the output member 16 to rotate synchronously through the buffer disc 18.

[0071] Preferably, the maximum torsion angle of the delay torsion spring 19 is not greater than ±120°, and the maximum torsion angle of the delay torsion spring 19 is not less than ±45°, and most preferably, the maximum torsion angle of the delay torsion spring 19 is ±90°. The maximum torsion angle of the delay torsion spring 19 is the angle of torsion from the input member 12 rotating relative to the output member 16 to the input member 12 driving the output member 16 to rotate synchronously through the buffer disc 18. The positive and negative are the angles of torsion of the delay torsion spring 19 when the input member 12 rotates forward or reversely. The delay timer 2 can obtain reasonable delay time for the controller within the above-mentioned angle range of 45°-120°. The delay time provided by the delay timer 2 is different when the maximum torsion angle of the delay torsion spring 19 is different, and the delay time provided by the delay timer 2 is different when the motor speed is different.

[0072] Figure 7 、 Figure 9 、 Figure 10As shown, preferably, the inner side surface of the limiting protrusion three 27 is a circular arc surface, the inner side surfaces of the two limiting protrusions three 27 enclose the shaft connecting space one 29, the inner side surface of the limiting protrusion four 25 is a circular arc surface, the inner side surfaces of the two limiting protrusions four 25 enclose the shaft connecting space two 30, the center of the buffer disc 18 is provided with a center hole, the support shaft 20 is inserted in the center hole, the two ends of the support shaft 20 are respectively inserted in the shaft connecting space one 29 and the shaft connecting space two 30, so that the input member 12, the buffer disc 18 and the output member 16 are connected on the same shaft to rotate, and the delay torsion spring 19 is sleeved outside the buffer disc 18.

[0073] The bearing mounting groove 15 is arranged in the sleeve body 3, the rear side of the bearing mounting groove 15 is communicated with the front end of the channel 21, the front side of the bearing mounting groove 15 is communicated with the opening two 11, the bearing 14 is mounted in the bearing mounting groove 15, and the output shaft 10 passes through the center of the bearing 14. The bearing 14 supports the output member 16 and limits the output member 16 to rotate in the sleeve body 3.

[0074] The side wall of the input member 12 and the side wall of the output member 16 are both provided with an outer ring edge 17, and the outer ring edge 17 is provided with a hole for inserting and connecting the end of the delay torsion spring 19.

[0075] Preferably, the controller is provided with a preset sub-module for setting a preset value for comparison with the working current

[0076] The controller is provided with a first current preset value, the first current preset value corresponds to the working current when the output shaft 10 is loaded and the delay torsion spring 19 starts to twist and deform, and when the controller detects that the working current reaches the first current preset value, the controller controls the motor to start to slow down.

[0077] The controller is provided with a second current preset value, the second current preset value corresponds to the working current when the output shaft 10 outputs a set torque, and when the controller detects that the working current reaches the second current preset value, the controller controls the rotary driving mechanism to stop rotating.

[0078] The controller is provided with a third current preset value, the third current preset value corresponds to the working current when the limiting protrusion four 25 at one end of the limiting protrusion two 23 and the protrusion movable space two 26 of the input member 12 pushes the buffer disc 18 to rotate relative to the output member 16 to just contact, when the controller detects that the working current reaches the third current preset value, the controller knows that the delay stroke is completed, the input member 12 and the output member 16 start to transmit power through the buffer disc 18, and the controller controls the motor speed.

[0079] When the bolt is tightened into the nut using an electric wrench, the wrench sleeve connected to the output shaft 10 is fitted onto the bolt head. The drive shaft 9 rotates to one side, causing the input component 12 to rotate, which in turn drives the output shaft 10 to rotate and output torque. When the bolt thread and the nut thread are close to being fully engaged and tightened, the load on the output shaft 10 begins to increase. At this time, the timer 2 enters the second state, and the input component 12 begins to rotate relative to the output component 16, causing the timer torsion spring 19 to begin to twist and deform. The torque output by the output shaft 10 begins to increase continuously, the motor's operating current begins to increase, and the timer begins to delay. This time point serves as the delay start point. At this time, the controller detects that the motor's operating current has reached the first preset current value, and the controller controls the motor to begin to decelerate rapidly. At this time, the input component 12 transmits power to the output component 16 only through the timer torsion spring 19, and the torque between the input component 12 and the output component 16 is transmitted only through the timer torsion spring 19. When the input component 12 pushes the buffer... When the disc 18 rotates relative to the output component 16 until the limiting protrusion 23 abuts against the limiting protrusion 4 25 at one end of the protrusion movement space 26, the delay timer 2 enters the third state, and the delay timer 2 ends. This time point is taken as the delay end point. The input component 12 pushes the output component 16 to rotate through the buffer disc 18. The input component 12 and the output component 16 transmit power only through the buffer disc 18, and the input component 12 and the output component 16 transmit torque together through the delay torsion spring 19 and the buffer disc 18. At this time, the controller detects that the motor's operating current has reached the third current preset value. Since the motor speed has dropped to the range that the controller can control after the delay stage, the controller begins to precisely control the operation of the motor. When the controller detects that the motor's operating current has reached the third current preset value, the torque output by the electric wrench reaches the set torque to fully tighten the bolt and nut. At this time, the controller precisely controls the motor to stop, realizing precise control of the torque output end point of the electric wrench.

[0080] like Figure 11 The figure shows the torque control curve when the wrench is tightening the bolt. NZ is the torque corresponding to the first current preset value, NE is the torque corresponding to the second current preset value, NS is the torque corresponding to the third current preset value, N is the motor speed trend, t is time, nm is torque, n is torque trend, ta is the delay start time, tb is the delay end time, and tf is the torque output end time.

[0081] The foregoing description of the electric wrench with precise torque output control and the timer for the electric wrench provided by this invention has illustrated the principles and implementation methods of the invention using specific examples. The descriptions of the embodiments above are merely for the purpose of helping to understand the invention and its core ideas. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. An electric wrench for precisely controlling torque output, comprising a body, wherein a controller and a rotary drive mechanism are provided within the body, the rotary drive mechanism includes a transmission shaft for transmitting rotational power, the controller is electrically connected to the rotary drive mechanism, and the controller includes a current sensing submodule for detecting the current during operation of the rotary drive mechanism, characterized in that... The machine body is equipped with a timer, which includes an input component, a buffer disk, an output component, and a time-delay torsion spring. The input component, buffer disk, and output component rotate around the same axis. The input component is connected to a drive shaft and can be driven to rotate by the drive shaft. The output component has an output shaft for outputting torque. The buffer disk is located between the input component and the output component for linkage connection between the input component and the output component. The buffer disk / input component has a first protrusion movable space, and the input component / buffer disk has a first limiting protrusion. The first limiting protrusion is movably arranged in the first protrusion movable space to limit the angle of rotation of the input component relative to the buffer disk. The buffer disk / output component has a second protrusion movable space, and the output component / buffer disk has a second limiting protrusion. The second limiting protrusion is movably arranged in the second protrusion movable space to limit the angle of rotation of the output component relative to the buffer disk. The time-delay torsion spring is located between the input component and the output component, and its two ends are respectively connected to the input component and the output component. When the drive shaft rotates forward or backward, the timer has the following states: In the first state, the output shaft is unloaded, and the input and output components rotate synchronously. In this state, the input and output components transmit power only through a time-delay torsion spring. In the second state, the output shaft is under load, and the input and output components rotate relative to each other to cause the time-delay torsion spring to deform. In this state, the input and output components transmit power only through the time-delay torsion spring. In the third state, the output shaft load is greater than a certain load. The first limiting protrusion abuts against one end of the first protrusion movable space, and the second limiting protrusion abuts against one end of the second protrusion movable space, so that the input and output components rotate synchronously. The time-delay torsion spring reaches the maximum torsion angle. In this state, the input and output components transmit power only through the buffer disk. When the delay is in the second state, the controller senses a change in current and controls the rotary drive mechanism to decelerate. In the third state, when the controller detects that the torque output by the output shaft reaches the set torque through current detection, the controller controls the rotary drive mechanism to stop. The controller has a first current preset value set inside. The first current preset value corresponds to the working current when the output shaft is loaded and the delay torsion spring begins to twist and deform. When the controller detects that the working current reaches the first current preset value, the controller controls the rotary drive mechanism to decelerate.

2. The electric wrench with precise torque output control according to claim 1, characterized in that, When the drive shaft rotates forward and in reverse, the maximum torsion angle of the time-delay torsion spring is the same.

3. The electric wrench with precise torque output control according to claim 1 or 2, characterized in that, The maximum torsion angle of the time-delay torsion spring shall not exceed ±120°, and the maximum torsion angle of the time-delay torsion spring shall not be less than ±45°.

4. The electric wrench with precise torque output control according to claim 1, characterized in that, The delay device also includes an outer casing. The input component, buffer disk, output component, and delay torsion spring are all housed within the outer casing. The output shaft extends from the front end of the outer casing to output torque. The outer casing is detachably connected to the front end of the main body. The rear end of the input component has a socket. The drive shaft extends from the front end of the main body and is inserted into the socket to drive the input component.

5. The electric wrench with precise torque output control according to claim 4, characterized in that, Two limiting protrusions 3 are provided on the end face of one end of the buffer disk / input component. The two limiting protrusions 3 enclose the protrusion activity space 1 for the insertion and movement of the limiting protrusion 1. Two limiting protrusions 4 are provided on the end face of one end of the buffer disk / output component. The two limiting protrusions 4 enclose the protrusion activity space 2 for the insertion and movement of the limiting protrusion 2.

6. The electric wrench with precise torque output control according to claim 5, characterized in that, The outer casing has channels for housing the input component, buffer plate, output component, and delay torsion spring. Two symmetrically arranged limiting protrusions (three) protrude from the end face of the input component facing the buffer plate, forming a protrusion movement space (one) between the ends of the two limiting protrusions (three). A corresponding limiting protrusion (one) is provided on the side of the buffer plate facing the input component. Two symmetrically arranged limiting protrusions (four) protrude from the end face of the output component facing the buffer plate, forming a protrusion movement space (two) between the ends of the two limiting protrusions (four). The side of the punch plate facing the output component is provided with a limiting protrusion two corresponding to the protrusion movement space two. The inner surface of the limiting protrusion three is an arc surface. The inner surfaces of the two limiting protrusion three enclose the shaft connection space one. The inner surface of the limiting protrusion four is an arc surface. The inner surfaces of the two limiting protrusion four enclose the shaft connection space two. A support shaft is inserted in the center of the buffer plate. The two ends of the support shaft are respectively inserted into the shaft connection space one and the shaft connection space two, so that the input component, the buffer plate and the output component are connected to rotate on the same shaft. The time delay torsion spring is sleeved on the outside of the buffer plate.

7. The electric wrench with precise torque output control according to claim 4, characterized in that, The outer casing has a socket at its rear end for insertion into the front end of the main body. The front end of the main body has an annular step on its side wall. The outer casing has screw holes, and the front end of the main body has a threaded hole corresponding to the screw holes. When the front end of the main body is inserted into the socket, the rear end of the outer casing rests against the annular step. The outer casing and the main body are fixed together by screws.

8. The electric wrench with precise torque output control according to claim 1, characterized in that, The controller has a second current preset value, which corresponds to the working current when the output shaft outputs a set torque. When the controller detects that the working current reaches the second current preset value, the controller controls the rotary drive mechanism to stop rotating.

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