Power tool

Abstract

The application discloses an electric tool, comprising: a functional part for realizing the function of the electric tool; a motor for driving the functional part; a driving circuit electrically connected with the motor to drive the motor; a first control module for outputting a first control signal to the driving circuit; the first control module has a first working state and a first failure state, the first control module outputs a first working signal when being in the first working state, and the first control module outputs a first failure signal when being in the first failure state; a second control module connected with the first control module to receive the first working signal or the first failure signal from the first control module; wherein the second control module outputs a second control signal to stop the motor when receiving the first failure signal from the first control module. The electric tool has high safety.

Description

TECHNICAL FIELD

[0001] The present application relates to a power tool, in particular to a power tool with high safety. BACKGROUND

[0002] Some existing power tools, for example, angle grinder, sander, reciprocating saw, circular saw, jigsaw, trimmer, chain saw, etc., have certain risks when working, and protective measures need to be taken for these power tools.

[0003] Taking the chain saw as an example, it is mainly used for logging and timber production, and its working principle is to perform a shearing action by the transverse movement of the staggered L-shaped blades on the saw chain. The chain saw usually uses a large current switch to control the start and stop of the motor, but as the working current continues to increase, it is difficult to select a large current switch, and a signal switch is used instead of a large current switch, and the motor running process is controlled by the controller to recognize the signal switch state, which puts higher requirements on the reliability of the power tool software system. Once the controller fails, it may cause serious safety accidents. SUMMARY

[0004] To solve the problems of the prior art, the purpose of the present application is to provide a power tool with high safety.

[0005] In order to achieve the above-mentioned goal, the technical scheme adopted by the present application is as follows:

[0006] A power tool, comprising: a functional part for realizing the function of the power tool; a motor for driving the functional part; a drive circuit electrically connected with the motor to drive the motor; a first control module for outputting a first control signal to the drive circuit; the first control module has a first working state and a first failure state, the first control module outputs a first working signal when in the first working state, and the first control module outputs a first failure signal when in the first failure state; a second control module connected with the first control module to receive the first working signal or the first failure signal from the first control module; wherein the second control module outputs a second control signal to stop the motor when receiving the first failure signal from the first control module.

[0007] Optionally, the first control module and the second control module are connected in communication with each other; the second control module has a second working state and a second failure state, the second control module outputs a second working signal to the first control module when in the second working state, and the second control module outputs a second failure signal to the first control module when in the second failure state; the first control module outputs a first control signal to stop the motor when receiving the second failure signal from the second control module.

[0008] Optionally, the electric tool further comprises a protection circuit electrically connected with the second control module, configured to stop the electric motor when receiving the second control signal of the second control module.

[0009] Optionally, the electric tool further comprises a power supply device configured to supply electric energy to the electric tool; the protection circuit comprises a switching circuit configured to disconnect the electric connection between the electric motor and the power supply device; the switching circuit comprises at least one electronic switch.

[0010] Optionally, the protection circuit further comprises a switching control circuit electrically connected with the switching circuit and the second control module, configured to control the switching circuit to be turned off to disconnect the electric connection between the electric motor and the power supply device according to the second control signal of the second control module.

[0011] Optionally, the driving circuit comprises a plurality of driving switches; the switching circuit comprises a first electronic switch electrically connected between the control terminals of at least part of the driving switches and the first control module, configured to disconnect the electric connection between the first control module and the control terminals of at least part of the driving switches; the switching control circuit comprises a second electronic switch electrically connected between the control terminal of the first electronic switch and the second control module, configured to control the first electronic switch to be turned off to disconnect the electric connection between the first control module and at least part of the driving switches to disconnect the electric connection between the electric motor and the power supply device according to the second control signal of the second control module.

[0012] Optionally, the driving circuit comprises a plurality of driving switches; the switching circuit comprises a third electronic switch electrically connected between the control terminals of at least part of the driving switches and a ground wire, and the control terminal of the third electronic switch is electrically connected with the second control module, configured to turn on the connection between at least part of the driving switches and the ground wire to disconnect the electric connection between the electric motor and the power supply device according to the second control signal of the second control module.

[0013] Optionally, the second control module comprises a control circuit, and the control circuit comprises at least one switching element.

[0014] Optionally, the second control module comprises a microcontroller.

[0015] Optionally, the electric tool further comprises a start switch configured to at least start the electric tool, and the start switch is connected with the first control module; the first control module is configured to output the first control signal to start the electric motor when detecting that the start switch is triggered and receiving the second working signal from the second control module.

[0016] Optionally, the electric tool further comprises a brake switch for braking the motor, the brake switch being connected with the first control module; the first control module is configured to output a first control signal to the drive circuit to brake the motor after detecting that the brake switch is triggered and receiving a second work signal from the second control module.

[0017] The present application has the advantage of improving the safety of the electric tool. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is an electric tool as an embodiment;

[0019] Figure 2 is Figure 1 is an internal structure diagram of the electric tool;

[0020] Figure 3 is a circuit block diagram of the electric tool as an embodiment;

[0021] Figure 4 is a circuit block diagram of the electric tool as another embodiment;

[0022] Figure 5 is Figure 3 is an embodiment of the drive circuit and the protection circuit in the electric tool;

[0023] Figure 6 is Figure 5 is a specific embodiment of the protection circuit in the electric tool;

[0024] Figure 7 is Figure 3 is another embodiment of the drive circuit and the protection circuit in the electric tool;

[0025] Figure 8 is Figure 7 is a specific embodiment of the protection circuit in the electric tool;

[0026] Figure 9 is Figure 4 is a specific embodiment of the drive circuit and the protection circuit in the electric tool;

[0027] Figure 10 is Figure 3 is a circuit block diagram of an embodiment of the electric tool, wherein the second control module comprises a control circuit;

[0028] Figure 11 is Figure 4 is a circuit block diagram of an embodiment of the electric tool, wherein the second control module comprises an MCU. DETAILED DESCRIPTION

[0029] The present application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] The electric power tool 10 of the present application can be a hand-held electric power tool, a garden tool, and the like, and is not limited to the same. The electric power tool of the present application includes, but is not limited to, the following: electric drills, impact drills, angle grinders, sanders, jigsaws, circular saws, curve saws, electric hammers, and the like, trimmers, chain saws, and the like, electric power tools that have a certain degree of danger. As long as these electric power tools can adopt the essential content of the technical solutions disclosed below, they fall within the protection scope of the present application.

[0031] Referring to Figure 1 and Figure 2 , as an embodiment, the electric power tool 10 takes a chain saw as an example, and the electric power tool 10 includes a housing 11, a front handle 12 and a main handle 13 arranged on the housing 11, a trigger mechanism 14 arranged on the main handle 13, a functional part 15 for realizing a specific function, a power supply device 16, and a motor 17 for driving the functional part 15 to move.

[0032] The functional part 15 is used to realize the function of the electric power tool 10. For a chain saw, the functional part 15 of the electric power tool 10 includes a saw chain 151 and a guide plate 152, which are used to realize the cutting function. The motor 17 is used to drive the functional part. For a chain saw, the saw chain 151 is wrapped around the edge of the guide plate 152 and can be circularly guided along the guide plate 152 under the driving of the motor 17. One end of the guide plate 152 is supported on the housing 11, and the other end extends out of the housing 11 in the longitudinal direction of the housing 11.

[0033] The trigger mechanism 14 is operable to be triggered by a user, and is used to control the start of the electric power tool 10. The trigger mechanism 14 can be, but is not limited to, a trigger. The electric power tool 10 further includes a start switch 18 connected with the trigger mechanism 14, which is arranged in the housing 11. When the trigger mechanism 14 is triggered, the start switch 18 associated with the trigger mechanism 14 is correspondingly triggered, and its trigger state changes.

[0034] The electric power tool 10 further comprises a power supply device 16 for providing power to the electric power tool 10. In some embodiments, the electric power tool 10 is powered by a direct current power supply, more specifically, the electric power tool 10 is powered by a battery pack, and the power supply device 16 comprises the battery pack. In other embodiments, the electric power tool 10 is powered by an alternating current power supply, which can be 120V or 220V alternating current mains, and the alternating current power supply is processed by a hardware circuit to rectify, filter, divide, step down, etc. the alternating current signal output by the power supply to convert the power into power that can be used by the electric power tool 10. In the present embodiment, the electric power tool 10 is powered by a battery pack, and the voltage output by the battery pack is changed in voltage by a specific power supply circuit (for example, a DC-DC conversion chip) to output a power supply voltage suitable for the motor 17, the control module, etc.

[0035] In order to enable the user to brake the electric power tool 10 in an emergency situation (for example, when danger occurs), the electric power tool 10 further comprises a brake control member 20 as an option, which is connected in association with a brake switch 21, which is a brake switch for enabling the motor 17 to enter a braking process. The brake control member 20 is a brake stopper in the present embodiment, and can rotate relative to the housing 11 about a fulcrum O. It can be understood that the brake control member 20 can also be provided in the form of a button according to actual design needs, and the button can be pressed to brake when braking is required. One end of the brake control member 20 forms a brake operation portion 201 for enabling an operator to perform a braking operation when a dangerous situation occurs, and the other end forms a cantilever arm 202 that can rotate relative to the housing 11, and the cantilever arm 202 can trigger the brake switch 21. By providing the above-mentioned manual brake control, the user can brake the electric power tool 10 at any time, and the use is convenient.

[0036] The normal operation of the electric power tool 10 described above also depends on a circuit system, at least part of the circuit components of the circuit system being arranged on a circuit board 19 arranged in the housing.

[0037] Referring to Figure 3 The circuit system of the electric power tool 10 as the first embodiment mainly comprises a first control module 31, a second control module 32, a drive circuit 35, a power supply device 36, and the above-mentioned motor 17.

[0038] The power supply device 36 is used to provide power to the electric power tool 10, and a battery pack can be selected as the power supply device 36. As an option, the electric power tool 10 further comprises a fuse (not shown) and a capacitor (not shown). The power supply device 36 is connected with the fuse, and the fuse 39 is used for overcurrent protection, and one end of the fuse is connected with the capacitor. The capacitor is used for filtering and absorbing ripple, and the capacitor is connected in parallel with the drive circuit 35.

[0039] The driving circuit 35 is connected with the motor 17 and used to drive the motor 17. The motor 17 comprises at least one phase resistance, for example, the motor 17 comprises a multi-phase winding, as an option, the motor 17 comprises a first phase winding A, a second phase winding B and a third phase winding C, the driving circuit 35 is electrically connected with three-phase electrodes U, V, W of the motor 17, the driving circuit 35 comprises a plurality of driving switches (for example, transistors) Figure 4 ), and of course, the winding of the motor 17 can be electrically connected with the power supply device 16 through the plurality of driving switches. The winding phase number of the motor 17 can also be other numbers.

[0040] The first control module 31 is connected with the driving circuit 35 and used to output a first control signal to the driving circuit 35. The first control signal is used to make the motor 17 operate or make the motor 17 stop, and the motor 17 stop comprises motor braking and motor stop working. It needs to be explained that the motor stop in the present application comprises motor braking and motor stop working, which will not be explained hereinafter.

[0041] Specifically, the first control module 31 is used to output the first control signal to the driving switches of the driving circuit 35, so as to control the on-off state of the driving switches of the driving circuit 35, thereby changing the voltage state loaded on the winding of the motor 17. The first control module 31 is electrically connected with the first power supply circuit 33 and powered by the first power supply circuit 33. The first power supply circuit 33 is connected with the power supply device 36 and connected with power supply by the power supply device 36, the voltage output by the power supply device 36 is changed in voltage by the first power supply circuit 33, and the power supply voltage suitable for the first control module 31 is output. The first power supply circuit 33 is for example a DC-DC conversion chip. The first control module 31 comprises but is not limited to MCU, DSP and the like.

[0042] The second control module is used to output a second control signal to make the motor 17 stop when receiving a first failure signal from the first control module. The second control module 32 is electrically connected with the second power supply circuit 34 and powered by the second power supply circuit 34. The second power supply circuit 34 is connected with the power supply device 36 and connected with power supply by the power supply device 36, the voltage output by the power supply device 36 is changed in voltage by the second power supply circuit 34, and the power supply voltage suitable for the second control module 32 is output. The second power supply circuit 34 is for example a DC-DC conversion chip. The second control module 32 comprises but is not limited to control circuit (for example, transistor) Figure 10 ), MCU (for example, transistor) Figure 11 ), DSP and the like. The first power supply circuit 33 and the second power supply circuit 34 can be separately arranged or integrated together.

[0043] The first control module 31 has a first working state and a first failure state. The first control module 31 outputs a first working signal when in the first working state, and outputs a first failure signal when in the first failure state. The first working signal and the first failure signal output by the first control module 31 are transmitted to the second control module 32. The second control module 32 is connected to the first control module 31 to receive the first working signal or the first failure signal from the first control module 31. The first working signal includes but is not limited to a pulse signal. When the second control module 32 receives the first failure signal from the first control module 31, the second control module 32 outputs a second control signal to stop the motor 17. The first failure signal can include no signal, a weak level signal, etc.

[0044] The electric tool 10 includes a protection circuit 37 electrically connected to the second control module 32, for stopping the motor 17 when receiving the second control signal of the second control module 32. In this way, when the first control module 31 fails, the second control module 32 can also provide backup protection, so that the motor 17 can be stopped in time when the first control module 31 fails, to avoid safety accidents and improve safety.

[0045] The protection circuit 37 includes a switching circuit 371 for disconnecting the electrical connection between the motor 17 and the power supply device 36. The switching circuit 371 can directly disconnect the electrical connection between the motor 17 and the power supply device 36, or indirectly disconnect the electrical connection between the motor 17 and the power supply device 36 through the driving circuit 35. The switching circuit 371 includes at least one electronic switch.

[0046] Figure 3 The protection circuit 37 shown, the switching circuit 371 is electrically connected between the first control module 31 and the driving circuit 35, and the switching circuit 371 includes an electronic switch S3, which disconnects the electrical connection between the first control module 31 and the driving circuit 35, thereby indirectly disconnecting the electrical connection between the motor 17 and the power supply device 36.

[0047] As an option, the protection circuit 37 further includes a switching control circuit 372 electrically connected to the second control module 32 and the switching circuit 371, for controlling the switching circuit 371 to shut down according to the second control signal of the second control module 32, to disconnect the electrical connection between the motor 17 and the power supply device 36. In this way, the switching circuit 371 indirectly disconnects the electrical connection between the motor 17 and the power supply device 36 through the control of the driving circuit 45.

[0048] Figure 4 The circuit system of the electric tool 10 shown, Figure 3The circuit system shown is similar, including: a first control module 41, a second control module 42, a first power supply circuit 43, a second power supply circuit 44, a drive circuit 45, and a power supply device 46. The above-mentioned circuit components are similar to... Figure 3 Similarities or resemblances will not be elaborated here. The difference lies in... Figure 4 The shown and Figure 3 The difference between the circuit systems shown lies in the different protection circuits.

[0049] Figure 4 The protection circuit 47 shown includes a switch circuit 471, which is electrically connected to the power supply device 46 and the power supply terminal of the drive circuit 45. The windings of the motor 17 can be electrically connected to the power supply device 46 through the power supply terminal of the drive circuit 45. In this way, the switch circuit 471 can directly disconnect the electrical connection between the power supply device 46 and the motor 17. Unlike... Figure 3 The switch circuit 371 shown is connected to the control terminal of the drive circuit 35 and the power supply device 36. In this embodiment, the switch circuit 471 can directly disconnect the electrical connection between the motor 17 and the power supply device 46.

[0050] Figure 5 As shown Figure 3 The driving circuit 55 and protection circuit 37 shown are an exemplary circuit. Exemplarily, the driving circuit 55 includes a three-phase bridge circuit composed of six driving switches VT1~VT6. The driving circuit 55 further includes: a first driving terminal 55a, for electrical connection to the first power supply terminal 56a of the power supply device 56; and a second driving terminal 55b, for electrical connection to the second power supply terminal 56b of the power supply device 56. Driving switches VT1, VT3, and VT5 in the driving circuit 55 are high-side driving switches, and VT2, VT4, and VT6 are low-side driving switches. Driving switches VT1~VT6 can be selected from field-effect transistors, IGBT transistors, etc. The driving circuit 55 is connected to the first control module 51. The driving switches VT1~VT6 change their on / off states according to the first control signal output by the first control module 51, thereby changing the voltage state applied by the power supply device 56 to the windings of the motor 17, driving the motor 17 to operate or turning off the motor 17. It should be noted that the driving circuit 55 can also be implemented in other ways, and the number of driving switches of the driving circuit 55 can also be other ways. It is not limited to the above-described implementation. The above is only an illustrative example and does not constitute a limitation on the present invention.

[0051] In this embodiment, the control terminals AH, AL, BH, BL, CH, CL of the driving switches VT1-VT6 are connected to the first control module 51 respectively. The high voltage terminals of the high side switches VT1, VT3, VT5 are connected to the first power terminal 56a of the power supply device 56 through the first driving terminal 55a, and the low voltage terminals of the high side switches VT1, VT3, VT5 are connected to the first phase winding A, the second phase winding B, the third phase winding C respectively; the high voltage terminals of the low side switches VT2, VT4, VT6 are connected to the first phase winding A, the second phase winding B, the third phase winding C respectively, and the low voltage terminals of the low side switches VT2, VT4, VT6 are connected to the second power terminal 56b of the power supply device 56 through the second driving terminal 55b. In this embodiment, the high side switches VT1, VT3, VT5 are used to turn on or turn off the electrical connection between the first phase winding A, the second phase winding B, the third phase winding C and the first power terminal 56a of the power supply device 56 respectively, and the low side switches VT2, VT4, VT6 are used to turn on or turn off the electrical connection between the first phase winding A, the second phase winding B, the third phase winding C and the second power terminal 56b of the power supply device 56 respectively.

[0052] For the driving circuit 55 of the three-phase bridge circuit and the three-phase motor 17, in this embodiment, the protection circuit 57 includes three protection circuit branches, which are the first protection circuit branch 571, the second protection circuit branch 572, and the third protection circuit branch 573 respectively. The three protection circuit branches are independent of each other and have the same or similar functions and compositions. The first protection circuit branch 571 is taken as an example for description below, and the other protection circuit branches are the same as or similar to it.

[0053] The first protection circuit branch 571 includes a switching circuit 571a and a switching control circuit 571b. The switching circuit 571a is connected between the control terminal of the low side switch VT2 and the first control module 51, and is used to disconnect the electrical connection between the control terminal of the low side switch VT2 and the first control module 51, so as to disconnect the electrical connection between the motor 17 and the power supply device 56 to make the motor 17 stop. The switching circuit 571a includes at least one electronic switch S5.

[0054] The switching control circuit 571b is electrically connected to the second control module 52, and is used to control the switching circuit 571a to turn off according to the second control signal of the second control module 52 to disconnect the electrical connection between the motor 17 and the power supply device 56.

[0055] Figure 6 A more specific example of the circuit of the power tool 10 is shown. Figure 5 The circuit system shown is similar to that shown in FIG. 1, and includes a first control module 61, a second control module 62, a first power supply circuit 63, a second power supply circuit 64, a driving circuit 65, and a power supply device 66. The various circuit components are connected as shown in FIG. 1. Figure 5 The circuit system shown is similar to that shown in FIG. 1, and includes a first control module 61, a second control module 62, a first power supply circuit 63, a second power supply circuit 64, a driving circuit 65, and a power supply device 66. The various circuit components are connected as shown in FIG. 1.Figure 5 Similarities or resemblances will not be elaborated here. The difference lies in... Figure 6 The shown and Figure 5 The difference in the circuit system shown is that the protection circuit is more specific.

[0056] Figure 6 An example is shown. Figure 5 The protection circuit 67 shown is a specific protection circuit 57. Protection circuit 67 includes a switching circuit and a switching control circuit. The switching circuit includes a first electronic switch (Q11, Q21, Q31) electrically connected between the control terminal of at least a portion of the drive switches in the drive circuit 65 and the first control module 61, used to disconnect the electrical connection between the first control module 61 and at least a portion of the drive switches in the drive circuit 65. The switching control circuit includes a second electronic switch (Q12, Q22, Q32) electrically connected between the first electronic switch (Q11, Q21, Q31) and the second control module 62, used to control the first electronic switch (Q11, Q21, Q31) to turn off according to a second control signal from the second control module 62, thereby disconnecting the electrical connection between the first control module 61 and at least a portion of the drive switches, and thus disconnecting the motor 17 from the power supply device 66.

[0057] and Figure 5 Similarly, Figure 6 The protection circuit 67 shown in one specific embodiment includes three protection branches: a first protection circuit branch 671, a second protection circuit branch 672, and a third protection circuit branch 673. The first protection circuit branch 671, the second protection circuit branch 672, and the third protection circuit branch 673 have the same or similar composition and function.

[0058] Taking the first protection circuit branch 671 as an example, the first protection circuit branch 671 includes a switching circuit 671a and a switching control circuit 671b. The switching circuit 671a includes a first electronic switch Q11 and a resistor R11, while the switching control circuit 671b includes resistors R12, R13, and R14, and a second electronic switch Q12. Optionally, both the first electronic switch Q11 and the second electronic switch Q12 are transistors.

[0059] Specifically, the first terminal of the first electronic switch Q11 is connected to the control terminal AL of the drive switch VT2 of the drive circuit 65, the second terminal of the first electronic switch Q11 is electrically connected to the first control module 61, and the control terminal of the first electronic switch Q11 is connected to the first terminal of the second electronic switch Q12 through a resistor R14. The control terminal of the first electronic switch Q11 is also connected to the second terminal of the first electronic switch Q11 through a resistor R11.

[0060] The first end of the second electronic switch Q12 is connected to the control end of the first electronic switch Q11 through the resistor R14, the second end of the second electronic switch Q12 is grounded, and the control end of the second electronic switch Q12 is connected to the second control module 62 through the resistor R12 and grounded through the resistor R13.

[0061] Since the first protection circuit branch 671, the second protection circuit branch 672, and the third protection circuit branch 673 are the same or similar in composition and function, the other protection circuit branches are not described here.

[0062] The working principle of the first protection circuit branch 671 is described below. During the operation of the electric tool 10, the first control module 61 as the main control module outputs the first control signal to the drive switch of the drive circuit 65 to control the on-off state of the drive switch, thereby changing the voltage state loaded on the winding of the motor 17 to realize the driving, speed regulation, and shutdown of the motor 17.

[0063] The first control module 61 has a first working state and a first failure state. When the first control module 61 is in the first working state, the first control module 61 normally works and can normally control the drive circuit 65 to perform the control work on the motor 17. During this process, it periodically or continuously outputs the first working signal to the second control module 62 to indicate that it is in a normal state. After receiving the first working signal from the first control module 61, the second control module 62 confirms that the second control module 62 is normal, and the first control module 61 does not perform any action. The first working signal can be but is not limited to a pulse signal.

[0064] When the first control module 61 is in the first failure state, the first control module 61 cannot normally work and cannot normally control the drive circuit 65. At this time, it outputs the first failure signal to the second control module 62. After receiving the first failure signal from the first control module 61, the second control module 62 outputs the second control signal to the protection circuit 67 to make the motor 17 stop. The first failure signal can be but is not limited to a weak level signal or no signal.

[0065] When the first control module 61 is in the first working state, the first control module 61 outputs the first working signal to the second control module 62, and the second control module 62 does not output the second control signal but outputs the high-level signal to the protection circuit 67. In this embodiment, the second control module 62 outputs the high level when powered on.

[0066] Taking the first protection circuit branch 671 as an example, the second electronic switch Q12 is turned on due to the high-level signal applied to the control terminal, so that the first electronic switch Q11 is turned on, and at this time the control terminal of the low-side drive switch VT2 can be electrically connected with the first control module 61. Similarly, the working principles and processes of the second protection circuit branch 672 and the third protection circuit branch 673 are the same as those of the first protection circuit branch 671, and the control terminals of the low-side drive switch VT4 and the low-side switch VT6 can be electrically connected with the first control module 61, so that the first control module 61 can normally control the drive circuit 65.

[0067] When the first control module 61 is in the first failure state, the first control module 61 outputs a first failure signal, and the second control module 62 outputs a second control signal after receiving the first failure signal output by the first control module 61, the second control signal being a low-level signal or a weak-level signal. At this time, the second electronic switch Q12 is turned off, so that the first electronic switch Q11 is turned off, and the electrical connection between the low-side switch VT2 of the drive circuit 65 and the first control module 61 is disconnected, and the low-side switch VT2 is turned off. Similarly, the working principles and processes of the second protection circuit branch 672 and the third protection circuit branch 673 are the same as those of the first protection circuit branch 671, and the low-side switch VT4 is turned off, and the low-side switch VT6 is turned off, so that the winding current loop of the motor 17 is cut off, and the motor 17 stops working, thereby stopping the driving function part 15.

[0068] In this way, when the first control module 61 is in the first failure state, the protection circuit 67 receives the second control signal of the second control module 62, the electrical connection between the control terminals of the low-side switches VT2, VT4, VT6 of the drive circuit 65 and the first control module 61 is disconnected, so that the power supply device 66 is disconnected from the winding of the motor 17, so that the motor 17 is stopped, and the safety of the electric tool 10 is improved.

[0069] Figure 7 Another exemplary embodiment of the drive circuit 35 and the protection circuit 37 is shown. Figure 3 Another exemplary embodiment of the drive circuit 35 and the protection circuit 37 is shown. Figure 5 Another exemplary embodiment of the drive circuit 35 and the protection circuit 37 is shown. Figure 6 Similarly, the circuit system of the electric tool 10 includes a first control module 71, a second control module 72, a first power supply circuit 73, a second power supply circuit 74, a drive circuit 75, and a power supply device 76. The above-mentioned various circuit components are the same as or similar to those of the electric tool 10 shown in FIG. 1, and will not be described here again. The difference is that, Figure 5 The protection circuit shown is different from that shown in FIG. 1. Figure 7 The protection circuit shown is different from that shown in FIG. 1. Figure 5 The protection circuit shown is different from that shown in FIG. 1. Figure 6 The protection circuit shown is different from that shown in FIG. 1.

[0070] Figure 7The protection circuit 77 shown is only one circuit, not as... Figure 5 and Figure 6 The three independent protection circuit branches are shown.

[0071] In this embodiment, the protection circuit 77 includes a switch circuit 771, which is used to disconnect the electrical connection between the motor 17 and the power supply device 76.

[0072] Connected to the second control module 72, the switch circuit 771 is used to connect at least a portion of the drive switch and the ground wire according to a second control signal from the second control module 72, thereby disconnecting the electrical connection between the motor 17 and the power supply device 76. The switch circuit 771 includes a third electronic switch S7.

[0073] In this embodiment, the control terminal of the third electronic switch S7 is electrically connected to the second control module 72, and is used to connect at least part of the connection between the drive switch and the grounding wire according to the second control signal of the second control module 72 so as to disconnect the electrical connection between the motor 17 and the power supply device 76.

[0074] Optionally, the protection circuit 77 further includes an isolation circuit 772, used to isolate the electrical connection between the protection circuit 77 and the drive circuit 75 when the first control module 71 is operating normally, so as to prevent the protection circuit 77 from affecting the drive circuit 75 and enable the drive circuit 75 to maintain normal operation under the control of the first control module 71. The isolation circuit 772 is connected to the control terminals of the low-side switches VT2, VT4 and VT6 of the drive circuit 75, and is also electrically connected to the switching circuit 771.

[0075] One end of the third electronic switch S7 is connected to the control terminals of the low-side switches VT2, VT4, and VT6 of the drive circuit 75 via the isolation circuit 772, and the other end of the electronic switch S7 is connected to the ground wire and grounded. The switch circuit 771 also includes a pull-up power supply Vcc for powering the switch circuit 771.

[0076] Figure 8 As shown Figure 7 A more specific exemplary circuit of the power tool 10 shown. (Compared to...) Figure 7 The circuit system shown is similar, including: a first control module 81, a second control module 82, a first power supply circuit 83, a second power supply circuit 84, a drive circuit 85, and a power supply device 86. The above-mentioned circuit components are similar to... Figure 7 Similarities or resemblances will not be elaborated here. The difference lies in... Figure 8 The shown and Figure 7 The difference in the circuit system shown is that the protection circuit is more specific.

[0077] Figure 8The protection circuit 87 shown specifically includes a switching circuit 871 and an isolation circuit 872, wherein the switching circuit 871 includes an electronic switch VT84, a resistor R81, a resistor R82, a resistor R83, a resistor R84, a pull-up power supply Vcc, and a unidirectional diode D4. The electronic switch VT84 is connected to the second control module 82 through the resistor R83 and grounded through the resistor R84. Figure 7 A specific embodiment of the third electronic switch S7 shown in the middle.

[0078] In the switching circuit 871, the electronic switch VT81 can be but is not limited to a MOSFET tube, the control end of the electronic switch VT81 is connected to the second control module 82 through the resistor R83 and grounded through the resistor R84. One end of the electronic switch VT81 is connected to the ground line (or grounded), and the other end of the electronic switch VT81 is connected to the pull-up power supply Vcc through the pull-up resistor R82 and connected to the isolation circuit 872 through the resistor R81.

[0079] The isolation circuit 872 includes three unidirectional diodes D1, D2, and D3. The negative end of each unidirectional diode D1, D2, and D3 in the isolation circuit 872 is connected to the other end of the electronic switch VT81 through the resistor R81, and the positive end of the unidirectional diode D1, D2, and D3 is connected to the control end of the low-side switch VT2, VT4, and VT6, respectively. The unidirectional diodes D1, D2, and D3 are used to isolate the electrical connection between the protection circuit 87 and the drive circuit 85 when the first control module 81 is working normally, so as to avoid the influence of the protection circuit 87 on the drive circuit 85, so that the drive circuit 85 can keep working normally under the control of the first control module 81.

[0080] The working principle of the protection circuit 87 in the embodiment is described below. When the first control module 81 is in the first working state, the first control module 81 outputs the first working signal to the second control module 82, the second control module 82 outputs a low-level signal or no signal, the electronic switch VT84 is not turned on, and the unidirectional diodes D1, D2, and D3 in the isolation circuit 872 are cut off, and the low-side drive switches VT2, VT4, and VT6 are still normally controlled by the first control module 81. In the embodiment, the second control module 82 is set to output a low-level signal or no signal when powered on.

[0081] When the first control module 81 is in the first failure state, the first control module 81 outputs a first failure signal to the second control module 82. When the second control module 82 receives the first failure signal, it outputs a second control signal to the protection circuit 87. The second control signal is a high-level signal, the electronic switch VT84 is turned on, the negative terminals of unidirectional diodes D1, D2, and D3 are pulled down to ground, the unidirectional diodes D1, D2, and D3 are turned on, the control terminal signals of the low-side drive switches VT2, VT4, and VT6 are pulled low, and the low-side drive switches VT2, VT4, and VT6 are turned off, thereby disconnecting the power supply device 86 from the motor 17.

[0082] Figure 9 As shown Figure 4 The specific implementation of the drive circuit 55 and protection circuit 57 in the circuit system of the power tool 10 shown.

[0083] and Figure 4 Similarly, the power tool 10 includes: a first control module 91, a second control module 92, a first power supply circuit 93, a second power supply circuit 94, a drive circuit 95, and a power supply device 96. The composition and function of each of the above circuit components are similar to... Figure 4 The composition and function of the drive circuit 95 are the same or similar. Figure 5 The same applies, so it will not be repeated here. The driving circuit 95 includes: a first driving terminal 95a, for electrically connecting to the first power supply terminal 96a of the power supply device 56; and a second driving terminal 95b, for electrically connecting to the second power supply terminal 96b of the power supply device 96.

[0084] Figure 9 The protection circuit 97 shown includes a switch circuit 971, which is electrically connected between the power supply device 96 and the second drive terminal 95b of the drive circuit 95. The winding of the motor 17 can be electrically connected to the power supply device 96 through the second drive terminal 95b of the drive circuit 95. In this way, the switch circuit 971 can directly disconnect the power supply device 96 from the motor 17.

[0085] Optionally, the protection circuit 97 specifically comprises a first electronic switch VT91, resistors R91, R92, R93, and R94, and a second electronic switch Q91. Optionally, the first electronic switch VT91 is a MOSFET, and the second electronic switch Q91 is a transistor.

[0086] The input end of the first electronic switch VT91, the output end of the first electronic switch VT91 and the second driving end 95b of the driving circuit 95 are connected in series. The control end of the first electronic switch VT91 is connected to the first end of the second electronic switch Q91 through the resistor R94. The control end of the first electronic switch VT91 is also connected to the second end of the first electronic switch VT91 through the pull-up resistor R91.

[0087] The first end of the second electronic switch Q91 is connected to the control end of the first electronic switch VT91 through the resistor R94, the second end of the second electronic switch Q91 is grounded, and the control end of the second electronic switch Q91 is connected to the power supply Vcc through the voltage dividing resistor R92 and grounded through the voltage dividing resistor R93. The protection circuit 97 further comprises a pull-up power supply Vcc for supplying power to the protection circuit 97.

[0088] Figure 10 The circuit system of the power tool 10 is the same as or similar to that shown in Figure 3 The difference is that, Figure 10 The second control module 120 in the embodiment specifically adopts a control circuit 121, and the control circuit 121 at least comprises an electronic switch.

[0089] In the embodiment, the circuit system of the power tool 10 comprises: a first control module 110, a second control module 120, a first power supply circuit 130, a second power supply circuit 140, a driving circuit 150, a power supply device 160, a protection circuit 170 and a motor 17. The functions and components of the above-mentioned various circuit components in the embodiment are the same as or similar to those shown in Figure 3 The functions and components of the above-mentioned various circuit components in the embodiment are the same as or similar to those shown in

[0090] Figure 11 The circuit system of the power tool 10 is the same as or similar to that shown in Figure 4 The difference is that, Figure 11 The first control module 210 and the second control module 220 shown in the embodiment are communicatively connected to each other, and the first control module 210 and the second control module 220 can be communicatively connected to each other to send signals to each other and receive signals from each other.

[0091] Figure 11 The circuit system of the power tool 10 comprises: a first control module 210, a second control module 220, a first power supply circuit 230, a second power supply circuit 240, a driving circuit 250, a power supply device 260, a protection circuit 270 and a motor 17. The functions and components of the above-mentioned various circuit components in the embodiment are the same as or similar to those shown in Figure 4 The functions and components of the above-mentioned various circuit components in the embodiment are the same as or similar to those shown in Figure 10 The second control module 120 in the circuit system shown in the embodiment can also adopt Figure 11The second control module 220 shown, Figure 11 The second control module 220 shown can also adopt Figure 10 The second control module 120 shown.

[0092] In this embodiment, the first control module 210 is configured to output a first control signal to the drive circuit 150 to speed up, drive, stop, etc. the motor 17. The first control module 210 has a first working state and a first failure state. When the first control module 210 is in the first working state, it outputs a first working signal to the second control module 220. When the first control module 210 is in the failure state, it outputs a first failure signal to the second control module 220.

[0093] In this embodiment, the second control module 220 also has a second working state and a second failure state. When the second control module 220 is in the second working state, it outputs a second working signal to the first control module 210. When the second control module 220 is in the failure state, it outputs a second failure signal to the first control module 210.

[0094] In this embodiment, the first control module 210 includes a first communication unit 212, and the second control module 220 further includes a second communication unit 222. The first communication unit 212 and the second communication unit 222 are communicatively connected to each other, which can be wireless communication or wired communication. The first control module 210 and the second control module 220 send signals to each other and receive signals from each other through the first communication unit 212 and the second communication unit 222. As an option, in this embodiment, the first control module 210 includes a control chip, such as an MCU, and the second control module 220 includes an MCU 221. The second control module 220 is connected to a protection circuit 270, which can adopt a protection circuit 47 as shown in Figure 4 The protection circuit 37 as shown in Figure 3 The protection circuit 37 as shown in

[0095] When the first control module 210 receives the second failure signal from the second control module 220, it outputs a first control signal to stop the motor 17. Specifically, when the first control module 210 receives the second failure signal from the second control module 220, it outputs a first control signal to the drive circuit 250 to stop the drive circuit 250 from working or to control the motor 17 to brake, thereby stopping the motor 17 and stopping the motor 17 from driving the functional part 15 of the power tool 10. The second failure signal can include no signal, a weak level signal, etc.

[0096] Similarly, the second control module 220 outputs a second control signal to the protection circuit 270 to make the motor 17 stop when receiving the first failure signal from the first control module 210. Specifically, the second control module 220 outputs the second control signal to the protection circuit 270 when receiving the first failure signal from the first control module 210, and the protection circuit 270 makes the motor 17 stop when receiving the second control signal from the second control module 220, in this way, the motor 17 stops driving the functional part. The first failure signal can include no signal, a weak level signal, etc.

[0097] In this embodiment, during the operation of the motor 17, the first control module 210 outputs the first control signal to make the motor 17 stop as soon as it receives the second failure signal from the second control module 220, and the second control module 220 outputs the second control signal to make the motor 17 stop as soon as it receives the first failure signal from the first control module 210, in this way, the safety accident or damage to the power tool 10 is avoided.

[0098] That is to say, during the operation of the power tool 10, when the first control module 210 and the second control module 220 are in a normal working state, the first control module 210 and the second control module 220 will send a working signal to each other to indicate that they are in a normal state to the other party, and the other party will maintain the status after receiving the working signal. The first working signal and the second working signal can be pulse signals. When the first control module 210 and the second control module 220 are in an abnormal failure state, they will send a failure signal to each other, and the other party will output a control signal to make the motor 17 stop after receiving the failure signal. In this way, when one of the control modules fails, the other control module can provide backup protection and make the motor 17 stop in time, so that the safety of the power tool 10 is higher.

[0099] In Figure 3 、 Figure 4 and Figure 10 、 Figure 11 the circuit system of the power tool 10 shown in the figure, the power tool 10 further comprises a starting switch 18, which is used at least to start the motor 17, and the starting switch 18 is connected with the first control module (31, 41, 110, 210). The starting switch 18 is connected with the trigger mechanism 14 in association, and the starting switch 18 connected with the trigger mechanism 14 in association is triggered accordingly, and the on-off state is changed.

[0100] The first control module (31, 41, 110, 210) also includes a switch detection unit (311, 411, 111, 211). The start switch 18 is connected to the switch detection unit (311, 411, 111, 211). The switch detection unit (311, 411, 111, 211) can detect the trigger state of the start switch 18 and thus make corresponding control based on the trigger state of the start switch 18. Specifically, when the switch detection unit 311 detects that the start switch 18 is triggered, the first control module (31, 41, 110, 210) outputs a first control signal to the drive circuit (35, 45, 150, 250) to control the drive circuit (35, 45, 150, 250) to start the motor 17.

[0101] Optionally, the start switch 18 can also be used to stop the motor 17. Specifically, the start switch 18 has two states—on and off. When the start switch 18 is on, it starts the motor 17; when the start switch 18 is off, it stops the motor 17. The switch detection units (311, 411, 111, 211) can detect the different states of the start switch 18, and thus output a first control signal to the drive circuit (35, 45, 150, 250) according to the different states of the start switch 18 to control the corresponding actions of the motor. Optionally, the start switch 18 is a signal switch.

[0102] Optionally, the power tool 10 also includes the aforementioned brake switch 21, which is connected to the first control module (31, 41, 110, 210) and used to brake the motor 17. Specifically, the brake switch 21 is connected to the switch detection unit (311, 411, 111, 211) of the first control module (31, 41, 110, 210). The switch detection unit 311 can detect the triggering state of the brake switch 21 and thus make corresponding control based on the triggering state of the brake switch 21. Specifically, when the switch detection unit 311 detects that the brake switch 21 is triggered, it outputs a first control signal to the drive circuit 35 to control the drive circuit 35 to brake the motor 17. Optionally, the brake switch 21 is a signal switch.

[0103] exist Figure 11 In the embodiment shown, the first control module 210 is further configured to: after detecting that the start switch 18 is triggered and receiving a second working signal from the second control module 220, output a first control signal to the drive circuit 250 to start the motor 17.

[0104] As an option, the start switch 18 has two states - an on state and an off state. When the switch detection unit (311, 411, 111, 211) detects that the start switch 18 is in the on state, the first control module (31, 41, 110, 210) outputs a first control signal to the drive circuit (35, 45, 150, 250) to control the motor to start. When the switch detection unit (311, 411, 111, 211) detects that the start switch 18 is in the off state, the first control module (31, 41, 110, 210) outputs a first control signal to the drive circuit (35, 45, 150, 250) to control the motor 17 to stop working. As an option, only when the switch detection unit (311, 411, 111, 211) detects that the start switch 18 is in the on state and the brake switch 21 is not triggered, the first control module (31, 41, 110, 210) outputs a first control signal to the drive circuit (35, 45, 150, 250) to control the motor to start.

[0105] The first control module 210 is further configured to output a first control signal to the drive circuit 65 to brake the motor 17 after detecting that the brake switch 21 is triggered and receiving a second working signal from the second control module 220.

[0106] In this way, only when the second control module 220 is in the second working state (normal working state), that is, only when the first control module 210 receives a second working signal from the second control module 220, the first control module 210 will work normally, that is, normally control the power tool and the motor 17 according to the state of the start switch 18 or the brake switch 21. Once the first control module 210 receives a second failure signal from the second control module 220, the first control module 210 will output a first control signal to the drive circuit 250 to shut down the motor 17 regardless of the state or whether the start switch 18 or the brake switch 21 is triggered. In this way, after the second control module 220 fails, the first control module can immediately shut down the motor 17.

[0107] Of course, as mentioned above, when the first control module 210 fails, the second control module 220 can also immediately output a second control signal to the protection circuit 270 to shut down the motor 17.

[0108] Through the above, in the present application, two control modules are provided, and after one of the control modules fails, the other control module can still provide backup protection, so that the safety of the power tool operation is higher.

[0109] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the above embodiments do not limit the present application in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation fall within the protection scope of the present application.

Claims

1. A power tool, comprising: a functional part for implementing a function of the power tool; a motor for driving the functional part; a driving circuit electrically connected to the motor for driving the motor; a first control module for outputting a first control signal to the driving circuit; the first control module has a first working state and a first failure state, the first control module outputs a first working signal when in the first working state, and the first control module outputs a first failure signal when in the first failure state; a second control module connected to the first control module for receiving the first working signal or the first failure signal from the first control module; wherein the second control module outputs a second control signal to stop the motor when receiving the first failure signal from the first control module; the first control module and the second control module are communicatively connected to each other; the second control module has a second working state and a second failure state, the second control module outputs a second working signal to the first control module when in the second working state, and the second control module outputs a second failure signal to the first control module when in the second failure state; the first control module outputs a first control signal to stop the motor when receiving the second failure signal from the second control module; further comprising a start switch for at least starting the power tool, the start switch being connected to the first control module; the first control module is configured to output a first control signal to start the motor when detecting that the start switch is triggered and receiving the second working signal from the second control module.

2. The power tool of claim 1, wherein: the power tool further comprises: a protection circuit electrically connected to the second control module for stopping the motor when receiving the second control signal of the second control module.

3. The power tool of claim 2, wherein: the power tool further comprises a power supply device for providing power to the power tool; the protection circuit comprises a switch circuit for disconnecting the electrical connection between the motor and the power supply device; the switch circuit comprises at least one electronic switch.

4. The power tool of claim 3, wherein: the protection circuit further comprises a switch control circuit, the switch control circuit being electrically connected to the switch circuit and the second control module for controlling the switch circuit to be turned off to disconnect the electrical connection between the motor and the power supply device according to the second control signal of the second control module.

5. The power tool of claim 4, wherein: the driving circuit comprises a plurality of driving switches; the switch circuit comprises a first electronic switch electrically connected between the control end of at least part of the driving switches and the first control module for disconnecting the electrical connection between the first control module and the control end of at least part of the driving switches. The switch control circuit comprises a second electronic switch electrically connected between the control end of the first electronic switch and the second control module, for controlling the first electronic switch to be turned off according to the second control signal of the second control module to disconnect the electrical connection between the first control module and at least part of the drive switches, so as to disconnect the electrical connection between the motor and the power supply device.

6. The power tool of claim 3, wherein: The drive circuit comprises a plurality of drive switches; The switch circuit comprises: A third electronic switch electrically connected between the control end of at least part of the drive switches and a ground line, and the control end of the third electronic switch is electrically connected with the second control module, for turning on the connection between at least part of the drive switches and the ground line according to the second control signal of the second control module to disconnect the electrical connection between the motor and the power supply device.

7. The power tool of claim 1, wherein: The second control module comprises a control circuit comprising at least one switching element; or the second control module comprises a microcontroller.

8. The power tool of claim 1, wherein: The power tool further comprises: A brake switch for braking the motor, the brake switch being connected with the first control module; The first control module is configured to output a first control signal to the drive circuit to brake the motor after detecting that the brake switch is triggered and receiving the second working signal from the second control module.

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