Power tool status indicator

Abstract

A power tool apparatus and a method of operating the same are provided. The power tool device has at least one sensor for detecting one or more operating parameters of the power tool; the motor comprises a rotor and a stator used for driving a working part. The motor is electrically connected with the power supply module. A controller is coupled to the at least one sensor for controlling operation of the motor by issuing a motor drive signal. The controller is configured to drive the motor such that the motor generates an audible sound and / or perceivable vibration upon determining that the power tool is in a predetermined operating state, which may be an active state or an abnormal state.

Description

Technical Field

[0001] The present disclosure relates to a status indicator for a power tool, particularly a power tool having an electric motor. Background Art

[0002] Battery-powered tools driven by corded electric motors are operated by users in a variety of environments to perform a variety of activities in and around the home, garden, or workshop. These activities may include, but are not limited to, trimming trees or hedges, drilling, blowing leaves off the ground, sawing wood, and the like. It should be understood that these tools are operated under a variety of environmental conditions, such as light and ambient noise.

[0003] Sometimes, a power tool may enter an abnormal or faulty state. Debris may become lodged in the tool, tool components may become stuck on the workpiece, or there may be a battery or electrical fault that may result in excessive current, voltage, or temperature, or other abnormal conditions. Some power tools may be equipped with protective circuitry that renders the tool inoperable when such an abnormal state occurs. In such cases, it is important to communicate to the user that the tool is in an abnormal state.

[0004] Typical methods of communicating an abnormal or fault condition to a user may be through the use of a visual indication on a screen, or the emission of a light or series of lights from a light emitter such as an LED or light bulb array. Other methods for indicating a fault condition may be through the communication of a notification to a personal electronic device via short-range wireless technology or the emission of a sound from a speaker contained in the device.

[0005] However, this notification method may cause inconvenience to the user or may not even attract the user's attention depending on the ambient conditions in which the power tool is operating. For example, when using the tool in bright daylight, the user may have difficulty seeing the light emitted from the light indicator device, or the user may be confused about the meaning of a particular light sequence.

[0006] It is therefore an object of the present disclosure to solve or at least partially ameliorate some of the above problems with current methods for indicating that a power tool has entered an abnormal state. Summary of the Invention

[0007] The features and advantages of the present disclosure will be set forth in the following description and, in part, will become apparent from the description, or may be learned by practicing the principles disclosed herein. The features and advantages of the present disclosure may be realized and obtained by the instruments and combinations particularly pointed out in the appended claims.

[0008] According to a first aspect of the present disclosure, a power tool device can be provided, which may include: at least one sensor for detecting one or more operating parameters of the power tool; a motor comprising a rotor and a stator for driving a working part, and the motor can be electrically connected to a power supply module; a controller connected to the at least one sensor, for controlling the operation of the motor by issuing one or more motor drive signals; wherein the controller is configured to drive the motor so that the motor can generate audible sound and / or perceptible vibration when it is determined that the power tool is in a predetermined state.

[0009] The predetermined state of the power tool may be selected from the group consisting of an abnormal operating state or an operable state.

[0010] The sensor may include at least one of: a temperature sensor for detecting the temperature of the motor and generating a temperature signal; a current sensor for detecting the current in the motor and generating a current signal; a voltage sensor for detecting the voltage on the motor and generating a voltage signal; a user input sensor for detecting the selected operating mode of the power tool device and user actuation of one or more trigger devices, and generating an input signal; and wherein the controller can receive at least one of the temperature signal, current signal, voltage signal and input signal to determine whether the tool is in the predetermined state.

[0011] The signal received by the controller can be processed to determine the status of the power tool based on whether the signal is likely to exceed a predetermined threshold, whether the signal is likely to exceed a predetermined threshold within a predetermined time period, or whether the rate of change of the base value of the signal is likely to exceed a predetermined acceptable rate of change.

[0012] The audible signal and / or vibration may be generated by controlling the rotor to change direction at a predetermined frequency.

[0013] The motor may be a brushless DC motor, and the controller may be configured to: after detecting an initial position of a rotor of the motor,

[0014] The controller may generate a first motor driving signal so that the direction of the current in the at least two coils of the stator and the magnetic field generated thereby may drive the rotor to rotate in a first direction within a first predetermined time period; and

[0015] The controller may generate a second motor driving signal so that the direction of the current in the at least two coils of the stator and the magnetic field generated thereby may drive the rotor to rotate in a second direction opposite to the first direction within a second predetermined time period; and

[0016] The controller may repeatedly switch between issuing the first motor drive signal and issuing the second motor drive signal to switch the rotation direction of the rotor in a third predetermined time period.

[0017] The motor may be a brushed DC motor, and the controller may be configured to:

[0018] The controller may generate a first motor driving signal so that the direction of the current in the rotor and the magnetic field generated thereby may drive the rotor to rotate in a first direction within a first predetermined time period; and

[0019] The controller may generate a second motor drive signal so that the direction of the current in the rotor and the magnetic field generated thereby may drive the rotor to rotate in a second direction opposite to the first direction within a second predetermined time period; and

[0020] The controller may repeatedly switch between issuing the first motor drive signal and issuing the second motor drive signal to switch the rotation direction of the rotor in a third predetermined time period.

[0021] The first and second predetermined time periods during which the direction of the current in the stator coil is switched may be selected to maximize the magnetic driving force on the rotor.

[0022] A first motor driving signal may be issued by the controller so that the direction of the current in the at least two coils of the stator and the magnetic field generated thereby can drive the rotor to rotate in a first direction within a first predetermined time period; and the rotor is driven by the cogging torque to rotate in a second direction opposite to the first direction;

[0023] The controller may repeatedly switch between issuing the first drive signal and allowing the cogging torque to switch the rotational direction of the rotor for another predetermined period of time.

[0024] The audible signal and / or vibration may be generated by controlling the stator to resonate at a predetermined frequency.

[0025] The power module may be configured to receive a removable power supply or configured to connect to a power supply.

[0026] According to a second aspect of the present disclosure, a method for causing a motor of a power tool to emit an audible sound and / or a perceptible vibration when the power tool is determined to be in a predetermined state may be provided. The method may include:

[0027] The motor controller may control the direction of current in one or more selected ones of the coils of the stator so that the magnetic field generated thereby may drive the rotor to rotate in a first direction for a first predetermined period of time;

[0028] The motor controller may control the direction of current in one or more selected ones of the coils of the stator so that the magnetic field generated thereby may drive the rotor to rotate in a second direction opposite to the first direction for a second predetermined period of time;

[0029] By controlling the direction of the current and selecting the stator coil through which the current flows, the motor controller may repeatedly switch the rotation direction of the rotor within a third predetermined period of time to generate an audible sound and / or a perceptible vibration.

[0030] The above-mentioned operating method of causing the motor of a power tool to emit audible sounds and / or perceptible vibrations may further include the following steps: detecting the initial position of the rotor of the motor relative to the coils of the stator of the motor (located around the rotor), wherein the motor may be a brushless motor.

[0031] According to a third aspect of the present disclosure, there may be provided an operating method for causing a motor of a power tool to emit an audible sound and / or a perceptible vibration when the power tool is determined to be in a predetermined operating state. The method may include:

[0032] The motor controller may control the direction of current in one or more selected ones of the coils of the stator so that the magnetic field generated thereby may drive the rotor to rotate in a first direction for a first predetermined period of time;

[0033] The rotor may be caused to rotate in a second direction opposite to the first direction for a second predetermined period of time;

[0034] By controlling the current direction and selecting the stator coils during the first predetermined time period, and allowing the cogging torque to drive the rotor, the motor controller can repeatedly switch the rotation direction of the rotor during a third predetermined time period to produce audible sounds and / or perceptible vibrations.

[0035] According to a fourth aspect of the present disclosure, a controller for a power tool may be provided, the controller being configured to drive a rotor of a motor of the power tool to operate according to any one of the above methods.

[0036] According to a fifth aspect of the present disclosure, an operating method can be provided for causing the motor of a power tool to emit an audible sound and / or perceptible vibration when it is determined that the power tool is in a predetermined state, the method comprising: determining the natural resonant frequency of the stator of the motor; and controlling the current in one or more selected coils of the stator coils by a motor controller to generate a resonance of the stator having a frequency substantially the same as the natural resonant frequency of the stator. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to illustrate the manner in which the above and other advantages and features of the present disclosure can be obtained, the principles briefly described above will be described in more detail by reference to specific embodiments of the present disclosure shown in the accompanying drawings. It should be understood that these drawings depict only exemplary embodiments of the present disclosure and are therefore not to be considered as limiting the scope of the present disclosure. The principles of this disclosure will be described and explained in more detail and in more detail through the use of the accompanying drawings.

[0038] Preferred embodiments of the present disclosure will be explained in further detail below by way of examples and with reference to the accompanying drawings, in which:-

[0039] Figure 1A Depicted are exemplary tools according to embodiments of the present disclosure.

[0040] Figure 1B Depicts Figure 1A An exemplary schematic module diagram of an exemplary tool.

[0041] Figure 1C Depicts Figure 1B An exemplary overview of the sensors.

[0042] Figure 2A Describes the use of Figure 1A An exemplary representation of an exemplary motor for a tool in which the rotor is stationary relative to the stator coils.

[0043] Figure 2B Depicts Figure 2A Schematic representation of a motor having energized coils AC and an initial rotation direction of the rotor produced thereby.

[0044] Figure 2C Depicts the current flowing through the coil AC Figure 2A Schematic representation of a motor.

[0045] Figure 2D Depicts Figure 2A Schematic representation of a motor having energized coils BC and the direction of rotation of the rotor generated thereby.

[0046] Figure 2E Depicts Figure 2A The motor is in Figure 2A An exemplary representation of the same state as depicted in FIG.

[0047] Figure 3A Depicts an exemplary flow chart showing the motor controller as the rotor passes through Figures 2A to 2E The depicted conditions are exemplary operations for signaling the brushless motor to produce audible noise and / or vibration.

[0048] Figure 3B Depicts an exemplary flow chart illustrating an alternative mode of operation of a motor controller, whereby current pulses are controlled to cause the rotor to pass through Figures 2A to 2E The depicted state is to produce audible noise and / or vibration.

[0049] Figure 3C Another exemplary flow chart illustrating an alternative mode of operation of a motor controller whereby stator resonance is controlled to produce audible noise and / or vibration is depicted. DETAILED DESCRIPTION

[0050] A number of different embodiments of the present disclosure are discussed in detail below. Although specific embodiments have been discussed, it should be understood that this is for illustrative purposes only. Those skilled in the relevant art will recognize that other components and configurations may be used without departing from the spirit and scope of the present disclosure.

[0051] The disclosed technology addresses the need in the art for a method of providing one or more notifications to an operator of a power tool when the power tool enters an abnormal or faulty state, either audibly or vibratingly, by controlling the operation of a motor to allow sound and / or vibration to be produced, as further described herein.

[0052] The above embodiments are described by way of example only. Many variations are possible without departing from the scope of the present disclosure as defined in the appended claims.

[0053] refer to Figure 1A , depicts an exemplary portable power tool 10. It should be understood that the exemplary power tool 10 can be powered directly by connecting to a mains power supply line, or can be powered by an onboard battery power source, but is not limited thereto. The power tool 10 can be a tool such as a screwdriver, a drill, an impact screwdriver, a chainsaw, a hedge trimmer, a blower, or the like. The power tool 10 includes a housing 12 in which components are enclosed, including typical components such as a motor 14, a gear assembly 16, and a driven member 18. Advantageously, the motor 14 can be coupled to the driven member via the gear assembly to provide a variable output torque and / or speed.

[0054] The controller circuit 20 is coupled to a power module 24 via a user actuation device 22. It will be appreciated that the power module 24 may receive therein a power source such as a battery or a transformer configured to change alternating current (AC) from the mains supply line to direct current (DC).

[0055] Now refer to Figure 1B , depicting Figure 1AFIG2 is an exemplary schematic diagram of the various components of the tool that control the operation of the motor 14. As shown, a sensor 30 is shown that is coupled to the power module and / or the motor 14 and is in communication with the controller 20. Advantageously, the user-actuated device 22 is a switch or trigger that is also coupled to the controller 20.

[0056] Now refer to Figure 1C , depicts a variation of exemplary sensors 30 that provide information to the controller 20. As shown, a temperature sensor 30a, a current sensor 30b, a voltage sensor 30c, and a speed sensor 30d are shown. It should be understood that other sensors may also be included, but are not limited thereto.

[0057] Further, as shown, a user input sensor 30e is provided that can send a signal to the controller 20. Advantageously, the signal can reflect various operating parameters, such as, but not limited to, the selected operating mode 32 or the actuation position of the trigger 34.

[0058] Advantageously, the operating parameters of the power tool indicated by the sensor can be provided to the controller and used to determine whether the power tool has entered an abnormal or faulty state. It should be understood that such a fault or abnormal state may be caused by a stuck driven member, insufficient operating voltage or current, an electrical fault in the power tool, or a variety of other reasons.

[0059] Alternatively, insertion of one or more current storage power cells or batteries or connection to a mains power source may also indicate that the power tool is in an operational state, utilizing vibrations and / or audible noises generated by a motor as further described herein. It will be understood that the vibrations of the motor will be transmitted to the tool housing and alert the operator that the tool is operational or that the tool is in an abnormal or faulty state, depending on the configuration as further described herein.

[0060] Other potential causes of a fault condition include: a jammed machine, excessive use (which would force the tool to stop), overheating, overloading, low voltage, etc. Those skilled in the art will appreciate that, in addition to indicating a fault condition or operating state, the audible sounds and / or vibrations of the present disclosure can be used to indicate any condition determined by the manufacturer, or even any condition that may be set by the user for specific operating conditions. For example, when the battery capacity is too low, the battery temperature is too high, or the battery is overloaded (current is too high), an audible prompt and / or vibration may also be generated according to the teachings of the present disclosure.

[0061] Advantageously, the controller 20 can be configured to receive a measurement signal from the sensor and determine whether the received signal is above or below a predetermined threshold. Alternatively, the controller can be configured to determine that the rate of change of the received signal is excessive. Various other methods can be employed to determine that the power tool has entered a fault or abnormal state based on signals received from one or more sensors without departing from the scope of the present disclosure.

[0062] Advantageously, the operating mode of the power tool for which the signal measurement value is received can also be determined to assess whether the power tool has entered a fault state or abnormal state. Optionally and alternatively, the user's actuation status of the user-actuated device can also be provided to the controller to determine the operating state of the power tool. It should be understood that without departing from the scope of the present disclosure, the controller can make this determination in conjunction with measurement signals received from one or more sensors, which measurement signals indicate operating parameter changes of one or more measurement parameters.

[0063] Upon determining that the signal received from the sensor indicates that the tool has entered a fault or abnormal state, the controller can be configured to prevent or limit further operation of the motor 14, for example by controlling the power supplied to the motor to terminate or reduce the operation of the motor, thereby causing the motor to jump, or otherwise cause the motor to enter an abnormal operating state.

[0064] It should be understood that Figures 1A to 1C The above-described components of the illustrated exemplary power tool and their operation are known in the art and will not be further described herein.

[0065] refer to Figures 2A to 2E , shows an exemplary schematic diagram of various operating stages of an exemplary brushless motor 50 in a power tool in an exemplary manner, wherein sound and / or vibration can be generated by the motor. It should be understood that the motor can be a brushed or brushless permanent magnet electric motor, but is not limited thereto.

[0066] As shown, the rotor 60 has permanent magnetic north and south poles (denoted by N and S) and is rotatably supported in the center of the stator. For ease of description, the various sectors through which the rotor rotates are shown in the figures. It should be understood that although six sectors are shown, the selection, location, and number of sectors are arbitrary and are shown solely for purposes of illustrating the movement of the rotor, as further described herein.

[0067] As shown, the stator is surrounded by the rotor and is schematically shown as including three separate coils labeled A, B, and C. It will be appreciated by those skilled in the art that these coils are connected to each other by conductive wires. Typically, these coils are excited by a voltage offset of 120° to produce a varying magnetic field that attracts or repels the poles of the permanent magnets of the rotor in different ways. The continuous change of the voltage (and therefore the current) in the coils causes the shaft connected to the rotor to rotate. Therefore, the varying current supplied to the stator coils is effectively converted into a rotating magnetic field for driving the rotor.

[0068] More specifically, as shown, the motor is in a stationary position when a fault condition is detected or when the controller 20 supplies initial power to the motor based on signals received from one or more sensors 30. The position of the rotor relative to each sector is then determined as described herein for a brushless motor, whereas no initial position detection is required for a brushed motor.

[0069] exist Figure 2A In the figure, the north pole of the rotor is located in sector 1 when in the initial position, but it should be understood that the position of the rotor is not limited to which sector it is determined to be located in, and the rotor can also be easily located in another sector.

[0070] like Figure 2B As shown, the switching pattern is then configured so that coil A is positive and coil C is negative, causing the excitation phase current to flow from A to C. It will be understood that the combined magnetic field generated by this current will cause the rotor to rotate in a clockwise direction, as shown in Figure 2. Figure 2B Indicated by the arrow.

[0071] This magnetic field causes the rotor to move, causing the north pole of the rotor 60 to move so that it is located in sector 2, as shown in FIG. Figure 2C shown.

[0072] After a predetermined time has passed since the current started flowing from A to C, the voltage is changed so that coil B is positive and coil C is negative. This causes the excitation phase current to flow from B to C and means that the magnetic field generated will push the rotor in an anti-clockwise direction, as shown in Figure 1. Figure 2D shown.

[0073] Finally, the rotor will be pushed into Figure 2E The position shown, whereby the north pole of rotor 60 is located in sector one.

[0074] Thus, in the example shown, by varying the voltage applied to the coils, the resulting current in the coils generates a varying magnetic field that is used to drive the rotor back and forth between sectors one and two.

[0075] The rotor oscillates between these two sectors at a resonant frequency, generating a noise which serves as an indicator to the user that the tool has entered a faulty or abnormal state.

[0076] Ensuring that the voltage switching pattern and phase currents are configured to maximize the generated magnetic field is crucial for maximizing the volume of the sound produced by the resonant rotor. For a given motor, the volume of the buzzer emitted by the motor is adjusted to maximum by the firmware for a given current drawn from the power supply or battery.

[0077] In an exemplary arrangement of a brushless motor, the following readings were taken at various time periods during the resonance / oscillation process. The frequency measurement range was from 0 to 10 kHz, and the motor had the following parameters: field winding / magnet: 1.0 / 15T, armature winding / magnet: N45SH. The primary frequencies recorded are shown in Table 1 below, but it should be understood that other frequencies can also be obtained.

[0078] Table 1:

[0079]

[0080] If a different motor with different characteristics is used, it will be understood that a different period may also be required to obtain the optimal oscillation frequency, as can be seen from different brushless motor types, where the field winding / magnets are 0.9 / 8.5T and the armature winding / magnets are N45M. In this case, the period chosen for a loud and clear high-pitched noise notification was 0.3 milliseconds.

[0081] Table 2:

[0082]

[0083]

[0084] As the PWM duty cycle and timer period increase, the vibration and decibel level will also increase, but it should be understood that the current drawn for this will also increase. As shown in Table 2 above, it should also be noted that by changing the timer period within a certain timer period range, as the timer period becomes larger, more low-frequency signals will be added, so there is an optimal timer period that can be determined for this arrangement.

[0085] Now refer to Figure 3A , depicting Figures 2A to 2E An exemplary schematic flow chart of the process shown in .

[0086] As shown in step 62 , the process begins when a fault or abnormal state of the power tool is determined, or when the power tool enters a predetermined state.

[0087] For a brushless motor, the initial position of the rotor is detected in step 64 and the rotor resonance or oscillation process begins. (For a brushed motor, this step is not performed, but the other subsequent steps are the same).

[0088] Next, a first timer (Timer CW) for the current sequence and rotor position is started in step 66. (It should be understood that the mode can be selected to be counterclockwise (CCW) depending on the rotor position without departing from the scope of this disclosure. This step is performed in both brushed and brushless motors).

[0089] Next, in step 68 , the voltage output switching pattern is configured to produce clockwise rotation from the determined rotor position. Once the first timer expires in step 70 , the first timer (in this case, timer CW) is disabled in step 72 .

[0090] Next, in step 74, a second timer for the rotor position of the current sequence is started (in this case, timer CCW) (it should be understood that the mode can be selected to be clockwise (CW) without departing from the scope of the present disclosure depending on the rotor position and the previous timer).

[0091] Then the output switching pattern of the voltage is changed in step 76 so as to produce counterclockwise rotation from the rotor position within a predetermined time. Once the second timer expires in step 78, this timer is disabled in step 80.

[0092] Each motor has a predetermined third time period during which the first timer and the second timer cycle.

[0093] If the predetermined period of motor resonance has expired, as shown by branch 82a, the rotor resonance / oscillation ends and the rapid switching of the coils described above ceases.

[0094] Alternatively, if the predetermined resonant time for the motor has not expired (as indicated by the branch represented by 82b), the process returns to step 66, in which the first timer is started to switch the voltage to the required coil to drive the rotor to rotate clockwise, and the process is repeated until the predetermined resonant time for the motor expires.

[0095] As shown in step 84 , the audible noise and / or vibrations emanating from the rotor resonance then cease.

[0096] When the rotor is in one of the six sectors (into which the rotor position is divided) and resonates, the volume generated by the rapid oscillation of the rotor is the largest. It should be understood that, especially when the power tool is used outdoors in an open and noisy environment, the maximum volume helps the user hear / feel the indication of an operational state or an abnormal fault state and then take appropriate corrective measures.

[0097] In such Figure 3BIn the alternative arrangement shown, an alternative way in which the rotor resonance or oscillation of a motor (brushed or brushless) can be achieved is provided by using the cogging torque.

[0098] In the arrangement shown, for a brushless motor, the resonance process begins by optionally detecting the initial position of the rotor in step 90. Those skilled in the art will appreciate that detecting the rotor position is not necessary for a brushed electric motor, but is optional for a brushless motor.

[0099] In step 92 , a clockwise (CW) or counterclockwise (CCW) timer for the current sequence is started, and in step 93 , an output switching mode is selected.

[0100] When the necessary timer is started, current flows in the appropriate direction to push and / or pull the rotor to the next position based on the interaction between the permanent magnetic poles of the rotor and the magnetic poles generated by the stator.

[0101] As known to those skilled in the art, at this stage, depending on the position of the rotor relative to the stator teeth, a variable cogging torque is generated between the permanent magnets in the rotor and the slots of the stator, which opposes the driving torque especially at low speeds.

[0102] While detecting the initial position of the rotor, the use of cogging torque to drive the motor is only suitable for brushless motors. Meanwhile, the use of cogging torque without detecting the initial position of the rotor can be suitable for both brushed and brushless motors.

[0103] For either a brushless or brushed motor, if the rotor position and current direction drive the rotor in a clockwise direction, a pause in the current flow will cause the cogging torque to drive the rotor in a counterclockwise direction. In this way, the associated timer for the rotor at a specific position (CW or CCW) can be activated to drive the rotor in only one direction, and the opposite direction rotor motion can be achieved under the influence of the inherent cogging torque to drive the rotor in the opposite direction.

[0104] If the CW / CCW timer for driving the rotor between positions in the current sequence has not expired (as shown in step 94b), the current sequence for driving the rotor continues.

[0105] Once the CW / CCW timer expires, the cogging torque drives the motor in reverse at step 94a and a predetermined timer for controlling the resonance / oscillation of the rotor is checked at step 98 to determine if that timer has also expired.

[0106] If the predetermined timer for the rotor to resonate / oscillate between positions has not expired (as shown in step 98b), the steps of enabling (driving rotation in one direction) and disabling (allowing rotation in the opposite direction driven by cogging torque) are repeated.

[0107] Once the resonance time expires in step 98 a , the rotor stops resonating in step 99 .

[0108] In an exemplary embodiment, the method performs measurements as listed in the following Table 3. It should be noted that the frequency of the emitted sound is composed of multiple frequencies, although Table 3 only shows the frequencies with the most dominant components.

[0109] Table 3:

[0110]

[0111] In yet another arrangement of resonance / oscillations described herein, the stator itself may be allowed to resonate rather than the rotor.

[0112] like Figure 3C As shown, in step 100, the appropriate pulse wave modulation and frequency and timer period are selected for the stator vibration of the specific motor based on predetermined experiments such as those shown in Tables 1 and 2 above (which experiments are described for the rotation of the rotor of a brushless motor).

[0113] Research shows that the main cause of electromagnetic vibration and noise in permanent magnet synchronous motors (PMSMs) with integer-slot multi-pole pairs is the resonance of the 0th-order electromagnetic force wave with the motor's natural frequency, so further research is needed to determine the optimal stator resonance.

[0114] A timer is started for a specific current sequence in step 102 and the output switching mode is entered in step 104. If the predetermined time period for stator resonance has not expired (as described in step 106b), the process is repeated and the stator is driven to resonance. This generates audible sound and / or vibration.

[0115] Alternatively, if the predetermined time period for the particular current sequence has expired (as described in step 106 a ), the timer is disabled in step 108 .

[0116] If the resonance time has not expired (see step 112b), the timer is restarted and the process returns to step 102. Alternatively, if the resonance time period has expired (step 112a), the current output switching sequence stops and the rotor stops resonating, and thus the audible noise and / or vibration stops, as described in step 114.

[0117] Methods and apparatus for generating audible noise and / or vibration in a motor that is transmitted to an operator via a housing provide an effective and efficient way to notify the operator that a power tool has entered a predetermined state. The predetermined state may be an active state of the power tool (e.g., once a battery has been inserted) or a fault state (e.g., when the operating temperature of the tool exceeds a predetermined threshold), as further described herein. Since no separate buzzer or transducer is required, the size and reliability of the power tool are not affected.

[0118] Additional advantages of the audible sound and / or vibration arrangement of the present disclosure may include: a reduction in additional electronic components (thus saving costs), and reduced wear and tear on electronic components. It will be appreciated that, given the standard of motors used in electric power tools, the additional load imposed on the motor by operation according to the present disclosure will not shorten the overall lifespan.

[0119] For clarity of explanation, the technology may in some cases be presented as including separate functional blocks including functional blocks comprising devices, device components, steps or routines.

[0120] Although various examples and other information are used to explain aspects within the scope of the appended claims, in such examples, no limitation to the claims should be implied based on specific features or arrangements, as a person of ordinary skill will be able to use these examples to derive a variety of implementations. Further, although some subject matter may have been described in language specific to examples of structural features and / or method steps, it should be understood that the subject matter defined in the appended claims is not necessarily limited to these features or actions described. For example, such functionality may be distributed differently or performed in components other than those identified herein. Instead, the described features and steps are disclosed as examples of components of systems and methods within the scope of the appended claims.

Claims

1. A power tool device (10), comprising: at least one sensor (30, 30a-e) for detecting one or more operating parameters of the power tool device (10); A motor (14, 50), the motor comprising a rotor (60) and a stator for driving a working component, the motor (14, 50) being electrically connected to a power supply module (24); a controller (20) coupled to the at least one sensor (30, 30a-e) for controlling operation of the motor (14, 50) by issuing one or more motor drive signals; The controller (20) is configured to drive the motor (14, 50) so that the motor (14, 50) generates an audible sound and / or a perceptible vibration when it is determined that the power tool device (10) is in a predetermined state.

2. The power tool device (10) according to claim 1, wherein: The predetermined state of the power tool device (10) is selected from the group consisting of an abnormal operating state or an operable state.

3. The power tool device (10) according to claim 1 or claim 2, wherein: The sensor (30, 30a-e) includes at least one of the following: a temperature sensor (30a) for detecting the temperature of the motor (14, 50) and generating a temperature signal; a current sensor (30b) for detecting a current in the motor (14, 50) and generating a current signal; a voltage sensor (30c) for detecting a voltage on the motor (14, 50) and generating a voltage signal; a user input sensor (30e) for detecting a selected operating mode of the power tool device (10) and user actuation of one or more triggering devices and generating an input signal; and The controller (20) receives at least one of the temperature signal, the current signal, the voltage signal, and the input signal to determine whether the power tool device (10) is in the predetermined state.

4. The power tool device (10) according to claim 3, wherein: The signal received by the controller (20) is processed to determine the status of the power tool device (10) based on whether the signal exceeds a predetermined threshold, whether the signal exceeds a predetermined threshold within a predetermined time period, or whether the rate of change of a base value of the signal exceeds a predetermined acceptable rate of change.

5. The power tool device (10) according to any one of claims 1 to 4, wherein: The audible signal and / or vibration is generated by controlling the rotor (60) to change direction at a predetermined frequency.

6. The power tool device (10) according to any one of claims 1 to 5, wherein: The motor (14, 50) is a brushless DC motor, and the controller (20) is configured to: after detecting an initial position of a rotor (60) of the motor (14, 50), The controller (20) issues a first motor drive signal so that the direction of the current in at least two coils (A, B, C) of the stator and the magnetic field generated thereby drive the rotor (60) to rotate in a first direction within a first predetermined time period; and The controller (20) issues a second motor drive signal so that the direction of the current in at least two coils (A, B, C) of the stator and the magnetic field generated thereby drive the rotor (60) to rotate in a second direction opposite to the first direction within a second predetermined time period; and The controller (20) repeatedly switches between issuing the first motor drive signal and issuing the second motor drive signal to switch the rotation direction of the rotor (60) in a third predetermined time period.

7. The power tool device (10) according to any one of claims 1 to 5, wherein: The motor (14, 50) is a brushed DC motor, and the controller (20) is configured to: The controller (20) issues a first motor drive signal so that the direction of the current in the rotor (60) and the magnetic field generated thereby drive the rotor (60) to rotate in a first direction within a first predetermined time period; and The controller (20) issues a second motor drive signal so that the direction of the current in the rotor (60) and the magnetic field generated thereby drive the rotor (60) to rotate in a second direction opposite to the first direction within a second predetermined time period; and The controller (20) repeatedly switches between issuing the first motor drive signal and issuing the second motor drive signal to switch the rotation direction of the rotor (60) in a third predetermined time period.

8. The power tool device (10) according to any one of claims 5 to 7, wherein: The first predetermined time period and the second predetermined time period during which the direction of the current in the stator coils (A, B, C) is switched are selected to maximize the magnetic driving force on the rotor (60).

9. The power tool device (10) according to any one of claims 1 to 5, wherein: The controller (20) issues a first motor drive signal so that the direction of the current in at least two coils (A, B, C) of the stator and the magnetic field generated thereby drive the rotor (60) to rotate in a first direction within a first predetermined time period; and The rotor (60) is driven by the cogging torque to rotate in a second direction opposite to the first direction; The controller (20) repeatedly switches between issuing the first drive signal and allowing the cogging torque to switch the rotation direction of the rotor (60) in another predetermined time period.

10. The power tool device (10) according to claim 1, wherein: The audible signal and / or vibration is emitted by controlling the stator to resonate at a predetermined frequency.

11. The power tool device (10) according to any one of claims 1 to 10, wherein: The power supply module (24) is configured to receive a detachable power supply or is configured to be connected to a power supply.

12. A method for causing a motor of a power tool device (10) to emit an audible sound and / or a perceptible vibration when determining that the power tool device (10) is in a predetermined state, comprising: controlling, by a motor controller (20), the direction of current in one or more selected coils (A, B, C) of the stator so that the magnetic field generated thereby drives the rotor (60) to rotate in a first direction within a first predetermined period of time; controlling, by the motor controller (20), the direction of current in one or more selected coils (A, B, C) of the stator so that the magnetic field generated thereby drives the rotor (60) to rotate in a second direction opposite to the first direction within a second predetermined period of time; By controlling the direction of the current and selecting the stator coils (A, B, C) through which the current flows, the motor controller (20) repeatedly switches the rotation direction of the rotor (60) within a third predetermined time period to generate audible sound and / or perceptible vibration.

13. The method of causing the motor (14, 50) of the power tool device (10) to emit an audible sound and / or a perceptible vibration according to claim 12, further comprising the following steps: An initial position of a rotor (60) of the motor (14, 50) relative to coils (A, B, C) of a stator of the motor (14, 50) is detected, wherein the motor (14, 50) is a brushless motor.

14. A method for causing a motor (14, 50) of a power tool device (10) to emit an audible sound and / or a perceptible vibration when the power tool device (10) is determined to be in a predetermined operating state, comprising: controlling, by a motor controller (20), the direction of current in one or more selected coils (A, B, C) of the stator so that the magnetic field generated thereby drives the rotor (60) to rotate in a first direction within a first predetermined period of time; rotating the rotor (60) in a second direction opposite to the first direction; By controlling the current direction and selecting the stator coil (A, B, C) through which the current flows during the first predetermined time period, and allowing the cogging torque to drive the rotor (60) during the second predetermined time period, the motor controller (20) repeatedly switches the rotation direction of the rotor (60) during another predetermined time period to generate audible sound and / or perceptible vibration.

15. A controller (20) for a power tool device (10), the controller being configured to drive a rotor (60) of a motor of the power tool device (10) to operate according to the method of any one of claims 12 to 14.

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