Handheld excavating tool

Abstract

The application discloses a handheld excavating tool, comprising: a drill rod mechanism, configured to rotate around a first axis to perform drilling; a driving mechanism, comprising a motor; the driving mechanism is configured to drive the drill rod mechanism to work; a supporting mechanism, configured to support the driving mechanism; a controller, configured to control the operation of the motor; the controller is configured to limit the torque output of the motor when the load parameter of the drill rod mechanism reaches a first threshold value, and the rotational displacement parameter of the supporting mechanism reaches a second threshold value. The handheld excavating tool has high safety performance.

Description

Technical Field

[0001] This application relates to a power tool, specifically a handheld excavator. Background Technology

[0002] Manually operated excavating devices, such as augers, are widely used in landscaping, planting, tree planting, geophysical exploration, road construction, and other fields. They are typically used for digging holes and drilling in sloping, sandy, or hard soil areas. They usually include a drive unit and a rotating drill bit, with auger blades mounted coaxially around the drill bit. An electric motor in the drive unit drives the drill bit and rotates the auger blades downwards into the soil.

[0003] Ice drills are mainly used for ice-breaking operations in the cold winter. Compared with soil drills, ice drills have different working surface characteristics and different performance requirements for the machine.

[0004] This section provides background information related to this application, which is not necessarily prior art. Summary of the Invention

[0005] One object of this application is to solve or at least alleviate some or all of the aforementioned problems. To this end, one object of this application is to provide a handheld excavation tool that offers better performance.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] A handheld excavating tool includes: a drill rod mechanism for rotating about a first axis to drill; a drive mechanism including a motor; the drive mechanism for driving the drill rod mechanism; a support mechanism for supporting the drive mechanism; and a controller for controlling the operation of the motor; the controller is configured to limit the torque output of the motor when the load parameter of the drill rod mechanism reaches a first threshold and the rotational displacement parameter of the support mechanism is detected to reach a second threshold.

[0008] In some embodiments, load parameters are used to characterize the torque of the drill pipe mechanism, and the load parameters include any one of motor current-related parameters and motor speed-related parameters.

[0009] In some embodiments, the rotational displacement parameters of the support mechanism include at least one of the following: the angle of rotation of the support mechanism about the first axis, the change in the angle, the angular acceleration, and the change in the angular acceleration.

[0010] In some embodiments, a position sensor is also included to acquire rotational displacement parameter information of the support mechanism when the motor is started.

[0011] In some embodiments, the controller is configured to control the motor to stop after a preset time when the motor current-related parameters meet the motor current protection threshold.

[0012] In some embodiments, the controller is configured to linearly reduce the motor speed from its current speed to a stop within a preset time period.

[0013] In some embodiments, a brake switch is also included for stopping the motor when it is triggered, and the controller is configured to limit the torque output of the motor when the change in the motor speed reaches a preset change threshold when the brake switch is not triggered.

[0014] In some embodiments, the controller is further configured to start the motor to drive the drill rod mechanism to move when the pressure parameter of the support mechanism along the first axis reaches the start threshold and the motor has power supply.

[0015] In some embodiments, the pressure parameters include at least one of the following: the displacement value of the support mechanism moving downward along the first axis direction, the downward pressure value of the support mechanism along the first axis direction, and the reaction force value of the support mechanism from the drill pipe mechanism along the first axis direction.

[0016] In some embodiments, an environmental monitoring component is also included for monitoring electrical wiring, gas lines, and water pipes within the working environment.

[0017] In some embodiments, the drill pipe mechanism includes: a first drill pipe mechanism having a first function and a second drill pipe mechanism having a second function; a drive mechanism is configured to be selectively connected to one of the first drill pipe mechanism and the second drill pipe mechanism to drive the first drill pipe mechanism to operate at a first output speed or the first drill pipe mechanism to operate at a second output speed.

[0018] The advantages of this application are: the load parameters of the drill pipe mechanism can characterize the stress state of the drill pipe mechanism, and the rotational displacement parameters of the support mechanism can characterize the tilting of the support mechanism or the main unit, abnormal displacements on the physical motion plane, etc. By coordinating different principles, they can adapt to more working conditions. Furthermore, the detection and verification methods of the two approaches can mutually correct the detection results, making the start-up of the process for limiting motor torque more accurate and safer. Attached Figure Description

[0019] Figure 1 This is a structural schematic diagram of the handheld excavation tool of this application, wherein the first drill rod mechanism is installed.

[0020] Figure 2 This is a schematic diagram of the main unit, the first drill rod mechanism, and the second drill rod mechanism in an embodiment of the handheld excavator of this application;

[0021] Figure 3 This is a structural schematic diagram of the host from another perspective in an embodiment of this application;

[0022] Figure 4 This is a schematic diagram of the internal structure of the host in the embodiments of this application;

[0023] Figure 5 This is a schematic diagram of the structure of the host (excluding the battery pack) and the first support part in the embodiments of this application;

[0024] Figure 6 yes Figure 5 A sectional view;

[0025] Figure 7 This is a schematic diagram of the support mechanism in the embodiments of this application;

[0026] Figure 8 yes Figure 7 Top view;

[0027] Figure 9 This is a structural diagram of the control mechanism in the embodiments of this application;

[0028] Figure 10 This is an electrical structure diagram of an embodiment in this application;

[0029] Figure 11 This is the control flowchart of the handheld excavation tool in this application. Detailed Implementation

[0030] Before explaining any implementation of this application in detail, it should be understood that this application is not limited to its application to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0031] In this application, the terms "comprising," "including," "having," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0032] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this application generally indicates that the preceding and following related objects have an "and / or" relationship.

[0033] In this application, the terms "connection," "combination," "coupling," and "installation" can refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, a direct connection refers to two parts or components being connected together without the need for an intermediary, while an indirect connection refers to two parts or components each being connected to at least one intermediary, with the connection achieved through the intermediary. Furthermore, "connection" and "coupling" are not limited to physical or mechanical connections or couplings, but can also include electrical connections or couplings.

[0034] In this application, those skilled in the art will understand that relative terms (e.g., “about,” “approximately,” “basically,” etc.) used in conjunction with quantities or conditions are to include the values ​​and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances associated with the particular value due to manufacturing, assembly, use, etc. Such terms should also be considered as disclosing a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​that do not use relative terms should also be disclosed as specific values ​​with tolerances. Furthermore, “basically” when expressing relative angular relationships (e.g., substantially parallel, substantially perpendicular) may refer to a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) added to or subtracted from the indicated angle.

[0035] In this application, those skilled in the art will understand that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0036] In this application, the directional terms "upper," "lower," "left," "right," "front," and "rear" are used to describe the orientation and positional relationships shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when an element is mentioned as being connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected through an intermediate element. It should also be understood that directional terms such as upper side, lower side, left side, right side, front side, and rear side not only represent positive orientation but can also be understood as lateral orientation. For example, "below" can include directly below, lower left, lower right, lower front, and lower rear.

[0037] To clearly illustrate the technical solution of this application, the terms "upper side", "lower side", "left side", "right side", "front side" and "rear side" are defined in the accompanying drawings.

[0038] like Figure 1A power tool 100 according to a first embodiment of this application is shown. In this embodiment, the power tool 100 is specifically a handheld digging tool. It will be understood that the power tool 100 may also be a handheld mixing tool.

[0039] A handheld excavator 100 is used to drill deep holes of a preset size in a substrate. In this embodiment, the handheld excavator 100 includes a main unit 1 and a first drill rod mechanism 2 having a first function. The first drill rod mechanism 2 is suitable for drilling in soil, for example, the substrate being soil, sand, a wall, or wood. When the main unit 1 is adapted to the first drill rod mechanism 2, the handheld excavator 100 is a ground drill. The main unit 1 is also adapted to at least a second drill rod mechanism 3 having a second function. The second drill rod mechanism 3 is suitable for drilling in ice. Both the first drill rod mechanism 2 and the second drill rod mechanism 3 are used to rotate about a first axis 101 to perform drilling along the direction of the first axis 101. When the main unit 1 is adapted to the second drill rod mechanism 3, the handheld excavator 100 is an ice drill. In this embodiment, the main unit 1 can be adapted to one of the first drill rod mechanism 2 and the second drill rod mechanism 3. Optionally, the first drill rod mechanism 2 and the second drill rod mechanism 3 may each have different diameters. Optionally, the first drill rod mechanism 2 and the second drill rod mechanism 3 may each have different lengths. Optionally, the main unit 1 can also be adapted to a third drill rod mechanism with different operating conditions than the first drill rod mechanism 2 and the second drill rod mechanism 3, which has a mutually cooperating interface with the main unit 1. The first drill rod mechanism 2 includes a drill shaft 21 and a spiral drill blade 22. The drill shaft 21 and the spiral drill blade 22 have different sizes and shapes for drill rod mechanisms with different functions. When it is a handheld mixing tool, the first drill rod mechanism includes a rotating shaft and spiral blades.

[0040] For ease of reference, the term "drill pipe mechanism" is used to refer to either the first drill pipe mechanism 2 or the second drill pipe mechanism 3, but this should not be construed as a limitation of this application.

[0041] like Figures 1 to 3 As shown, the main unit 1 includes a support mechanism 11, a drive mechanism 12, and a power supply. The support mechanism 11 supports the drive mechanism 12. The power supply is a battery pack 13, which, in conjunction with a corresponding power circuit, supplies power to at least the drive mechanism 12 within the handheld excavator 100. Those skilled in the art should understand that the power supply is not limited to the scenario using the battery pack 13; it can also be supplied by mains power or AC power, in conjunction with corresponding rectification, filtering, and voltage regulation circuits, to power corresponding components within the machine.

[0042] In this embodiment, the nominal voltage of battery pack 13 is greater than 40V and less than 80V. In some embodiments, the nominal voltage of battery pack 13 is greater than or equal to 40V and less than or equal to 80V. In some embodiments, the nominal voltage of battery pack 13 is 56V. The capacity of battery pack 13 is 4Ah to 5Ah. In some embodiments, the capacity of battery pack 13 is 2.5Ah to 12Ah. Optionally, battery pack 21 may be a lithium battery pack, a solid-state battery pack, or a pouch battery pack.

[0043] like Figures 4 to 6 As shown, the drive mechanism 12 includes a motor 121. The motor 121 drives the drill rod mechanism. In this embodiment, the motor 121 is a DC motor. Optionally, the motor 121 is an external rotor brushless DC motor. Figure 6 As shown, the motor 121 includes a stator 1211 and a rotor. The stator 1211 includes a stator core and stator windings. The rotor 1213 includes a rotor core and permanent magnets. A motor shaft 1215, rotating about the motor axis 102, is formed or connected to the rotor 1213 for outputting power. For an external rotor motor, the rotor is sleeved outside the stator. In some embodiments, the outer diameter of the motor 121 is greater than or equal to φ60mm. In some embodiments, the outer diameter of the motor 121 is greater than or equal to φ80mm. In some embodiments, the outer diameter of the motor 121 is greater than or equal to φ90mm. In some embodiments, the outer diameter of the motor 121 is greater than or equal to φ100mm. In this embodiment, the outer diameter of the motor 121 is φ105mm.

[0044] In some embodiments, such as Figure 10 As shown, motor 121 is a three-phase brushless motor, including a rotor with permanent magnets and three-phase stator windings U, V, and W that are electronically commutated. In some embodiments, the three-phase stator windings U, V, and W are connected in a star configuration, and in other embodiments, they are connected in a delta configuration. However, it must be understood that other types of brushless motors are also within the scope of this disclosure. Brushless motors may include fewer or more than three phases.

[0045] In this embodiment, the handheld excavator 100 outputs a maximum torque greater than or equal to 80 N·m. In some embodiments, the handheld excavator 100 outputs a maximum torque greater than or equal to 81 N·m, 83 N·m, 85 N·m, 88 N·m, or 90 N·m. In this application, when using a DC power supply, the output torque of the handheld excavator can reach the level of AC products.

[0046] In this embodiment, the weight of the handheld excavator 100 after installing the battery pack 13 is greater than or equal to 10 kg and less than or equal to 25 kg. The weight of the handheld excavator 100 after installing the battery pack 13 is greater than or equal to 14 kg and less than or equal to 25 kg. The weight of the handheld excavator 100 after installing the battery pack 13 is greater than or equal to 14 kg and less than or equal to 20 kg. The nominal voltage of the battery pack 13 is greater than 40V, and the ratio of the maximum output torque of the handheld excavator 100 to its weight is greater than or equal to 4.0 N·m / kg. In this embodiment, by using an external rotor motor, the motor output performance is improved, resulting in high output torque per unit weight. On the other hand, the nominal voltage of the battery pack is less than 80V, which reduces the weight of the machine. The use of a high-performance motor further enhances the high output torque per unit weight of the handheld excavator of this application.

[0047] In some embodiments, the ratio of the maximum output torque of the handheld excavator 100 to the capacity of the battery pack 13 is greater than or equal to 20 N·m / Ah. As is known in related technologies, a high output torque necessarily corresponds to a high current and low speed, while the capacity of the battery pack 13 is related to its current. The purpose of setting the ratio of the maximum output torque to the battery pack 13 to be greater than or equal to 20 N·m / Ah in this application is to achieve a balance between the output torque of the motor 121 and the high current. This improves the performance of the motor 121, ensuring that the motor 121 can output high torque without increasing the current, thus improving the performance of the handheld excavator 100. It also allows for compatibility with the performance requirements of ice drills and soil drills. Furthermore, it effectively avoids irreversible damage to the battery pack 13 caused by overcurrent and temperature rise.

[0048] The handheld excavator 100 includes at least a first output speed adapted to a first function and a second output speed adapted to a second function. Optionally, the drive mechanism includes a first gear for outputting the first output speed and a second gear for outputting the second output speed. Optionally, the motor 121 includes at least a high-speed gear and a low-speed gear. Specifically, in the high-speed gear, the motor speed is greater than or equal to 5500 rpm and less than or equal to 7000 rpm. In the low-speed gear, the motor speed is greater than or equal to 4500 rpm and less than or equal to 6000 rpm. Optionally, the first output speed is any speed value or speed range in the high-speed gear. The second output speed is any speed value or speed range in the low-speed gear. The first output speed and the second output speed are different. In some embodiments, the maximum values ​​of the first output speed and the second output speed are different. In some embodiments, the first output speed and the second output speed are mostly different, but there will be a moment or a time period during the entire operation when the output speeds are the same.

[0049] like Figures 4 to 6As shown, the drive mechanism 12 also includes a transmission assembly 14 and an output shaft 125. One end of the transmission assembly 14 engages with the motor 121, and the other end engages with the output shaft 125 to transmit the power output by the motor 121 to the output shaft 125. The output shaft 125 can be fitted with both the first drill rod mechanism 2 and the second drill rod mechanism 3 via fasteners. The output shaft 125, the first drill rod mechanism 2, and the second drill rod mechanism 3 are all concentrically and coaxially arranged.

[0050] In this embodiment, the transmission assembly 14 is a reduction gearbox. Optionally, the transmission assembly uses a reduction torque-increasing gear mechanism to further enhance the working capacity of the handheld excavator. The transmission assembly 14 includes a cylindrical gear transmission. Optionally, the transmission assembly 14 includes a first driving gear 141, a first driven gear 142, an intermediate shaft 143, a second driving gear 144, and a second driven gear 145. The first driving gear 141 is formed or connected to the end of the motor shaft 1215. The first driving gear 141 rotates about the motor axis 102. The first driving gear 141 drives the first driven gear 142. The first driven gear 142 meshes externally with the first driving gear 141. The first driven gear 142 is connected to the intermediate shaft 143. The first driving gear 141 and the first driven gear 142 form a reduction transmission. The intermediate shaft 143 rotates about a third axis 103. A second driving gear 144 is formed or connected to the intermediate shaft 143. The second driving gear 144 drives the second driven gear 145. The second driven gear 145 meshes externally with the second driving gear 144. The second driving gear 144 and the second driven gear 145 form a reduction transmission. The second driven gear 145 is connected to the output shaft 125. The second driven gear 145 rotates about the first axis 101. The working capacity of the handheld excavator is improved by using a two-stage reduction transmission. In this embodiment, the rotational speed of the first drill rod mechanism 2 is greater than or equal to 50 rpm and less than or equal to 220 rpm.

[0051] like Figure 1-3 and Figures 5-8 As shown, the support mechanism 11 supports the drive mechanism 12. The support mechanism 11 includes a first support portion 111 and a handle frame 112. The first support portion 111 is basically plate-shaped or disc-shaped with flanges. The first support portion 111 is fixedly installed with the handle frame 112. The first support portion 111 is provided with a through hole 1111 that mates with the drive mechanism 12 and a torque-bearing member. The torque-bearing member is used to bear the torque transmitted from the drive mechanism 12 to the first support portion 111. The number of torque-bearing members can be set as needed. When there are multiple torque-bearing members, the torque-bearing members are evenly distributed around the periphery of the through hole 1111. This arrangement allows each torque-bearing member to bear nearly equal torque, thereby effectively avoiding damage to some torque-bearing members due to uneven torque bearing.

[0052] The handle 112 bends upwards and extends along the periphery of the first support 111. For example... Figure 3 and Figures 7 to 8 As shown, the handle frame 112 includes a main handle frame 113, a first handle 114, and a second handle 115. The main handle frame 113 is connected to a first support portion 111. The first support portion 111 is fixedly mounted on the main handle frame 113 using fasteners. Figure 3 and Figure 8 As shown, the first side 112a of the handle frame 112 forms a first accommodating space 112b for accommodating the operator. In this embodiment, the first side 112a is the side closer to the operator, i.e., the rear side. The opposite side of the first side 112a is the second side 112c of the handle frame 112, which is the front side. The first handle 114 and the second handle 115 extend from the first side 112a to the second side 112c, i.e., from the rear side to the front side. Optionally, the first handle 114 and the second handle 115 do not necessarily extend horizontally in the front-back direction; they extend from the direction of the first side 112a to the direction of the second side 112c and have a certain inclination in the vertical direction. The first handle 114 and the second handle 115 may have a higher vertical position than the main handle frame 113 and the first support 111. In other words, when the operator holds the two handles and operates the power tool 100, the main handle frame 113 and the first support 111 can be at the level of the operator's waist or thigh. In this embodiment, the portions of the first handle 114 and the second handle 115 located on the first side 112a are respectively provided with protective sleeves 116. The protective sleeves 116 are made of soft material. The protective sleeves 116 are arranged substantially around the first receiving space 112b and are used to protect the user.

[0053] like Figure 6-8 As shown, the first handle 114 and the second handle 115 extend closer to each other from the first side 112a to the second side 112c. Along the first axis 101, the angle α between the projection of the first handle 114 and the front-back direction is greater than 0° and less than or equal to 30°. In some embodiments, the vertical line connecting the first side 112a and the second side 112c perpendicular to the first axis 101 is defined as the second axis. That is, the front-back direction is the direction of the second axis. The direction from the first side 112a to the second side 112c is the positive direction, that is, the direction from back to front is the positive direction. When projecting the second axis and the first handle 114 along the first axis 101, the angle α between the positive direction of the second axis and the projection of the first handle 114 is greater than 0° and less than or equal to 30°. In some embodiments, the angle α between the positive direction of the second axis and the projection of the first handle 114 is greater than 0° and less than or equal to 15°. This design better suits the operator's usage habits, providing a better grip experience. The operator can apply sufficient torque without much difficulty.

[0054] In this embodiment, the first handle 114 and the second handle 115 are symmetrically arranged with respect to a first plane AA. The first axis 101 lies within the first plane, and the first plane is parallel to the second axis 102. In this embodiment, the first plane is the AA plane in the front-to-back direction. Optionally, the first handle 114 and the second handle 115 are symmetrical with respect to the first plane, and the first plane AA is coplanar with the first axis 101 of the drill rod mechanism. This is more advantageous for the operator to apply force. On the first side 112a of the handle frame 112, the vertical distance between the first handle 114 and the second handle 115 is L1, and on the second side 112c of the handle frame 112, the vertical distance between the first handle 114 and the second handle 115 is L2, wherein L1 is greater than L2, and L1 is greater than or equal to 550 mm and less than or equal to 650 mm.

[0055] The first handle 114 is provided with a first grip portion 1141 for holding, and the second handle 115 is provided with a second grip portion for holding. The vertical distance between the first grip portion 1141 and the second grip portion is greater than or equal to 550 mm and less than or equal to 600 mm. The vertical line connecting the force application point P of the first grip portion 1141 and the force application point P of the second grip portion intersects the first axis 101. The vertical distance between the first grip portion 1141 and the second grip portion is the vertical distance between the two force application points. Optionally, the first grip portion 1141 and the second grip portion respectively include a grasping portion that conforms to the palm and a finger-gripping portion that accommodates the palm, with the force application point basically located at the center of the grasping portion. Based on the average palm width of an adult, the force application point is basically located 20 mm to 35 mm offset from the finger-gripping position of the thumb towards the grasping portion.

[0056] In this embodiment, the first grip portion 1141 on one side of the first handle 114 is configured as a grip sleeve, and the second grip portion on one side of the second handle 115 is equipped with a handle assembly 15. When the power tool 100 is in normal working condition, the handle assembly 15 is located on the second handle 115 held by the operator's right hand. Setting an appropriate distance is beneficial for the operator's control of the machine. At the same time, the intersection of the grip point with the first axis 101 is more conducive to the operator's control of the machine when torque is output.

[0057] like Figures 4-8As shown, the handle assembly 15 includes a handle housing 151, a switch unit 152, a locking unit 153, and a reversing shift unit 154. The handle housing 151 includes a top wall, a bottom wall opposite to the top wall, and a side wall. The top wall, bottom wall, and side wall together form a receiving cavity to house the actuation unit, locking unit 153, and reversing shift unit 154. The switch unit 152 includes a trigger 1521 pivotally mounted on the handle housing 151, an actuation switch 1522 cooperating with the trigger, and a trigger reset elastic element. The trigger 1521 is for user operation. The trigger 1521 passes through the bottom wall facing the handle housing 151. Optionally, the bottom wall of the handle housing 151 includes a finger grip position to accommodate four fingers of the user. This arrangement allows the user to operate the trigger with four fingers when holding the handle assembly 15, thus providing great convenience to the operator. When the start switch 1522 (e.g., a micro switch) directly sends a start signal to the drive mechanism 12, this indicates that the start switch 1522 directly controls the operation of the drive mechanism 12. When the start switch 1522 (e.g., a signal switch) sends a start signal to the control unit, and the control unit then controls the operation of the drive mechanism 12, this indicates that the start switch 1522 indirectly controls the operation of the drive mechanism 12. When the trigger is released, the trigger resets under the action of the trigger reset elastic element.

[0058] like Figures 3 to 6 As shown, the first support 111 and the handle bracket 112 form a second receiving space 112d, within which at least a portion of the drive mechanism 12 is housed. The drive mechanism 12 is mounted on the first support 111 and is used to drive the drill pipe assembly. The drive mechanism 12 also includes a housing 122 and an air guide shroud 123. The housing 122 and the air guide shroud 123 form a receiving cavity. The receiving cavity is used to house the motor 121, the transmission assembly 14, and the control mechanism 16.

[0059] The drive mechanism 12 is fixedly mounted on the first support 111 by fasteners. The housing 122 is provided with a battery connection 126. The battery connection 126 is used to connect the battery pack 13. In this embodiment, the battery connection 126 is located on the side of the motor 121 closer to the operator. This maximizes the distance between the operator and the drill rod mechanism, thereby ensuring the operator's safety. In this embodiment, the battery connection 126 is symmetrical about the first plane AA, and the plane of symmetry of the battery connection 126 is coplanar with the first axis 101. This arrangement ensures that the weight of the battery pack 13 is equal on both sides of the plane of symmetry, thus facilitating the user's balance of the power tool 100.

[0060] A fan 124 is provided at the end of the motor 121 away from the transmission assembly 14. An air outlet 1231 is provided on the side of the air guide shroud 123 facing the motor 121. In this embodiment, at least two air outlets 1231 are provided. Optionally, at least one air outlet 1231 is provided in each of the left and right directions. The air inlet 1231 is basically arranged around the fan 124.

[0061] like Figures 9 to 10 As shown, the control mechanism 16 is used to control the operation of the motor 121. In this embodiment, the control mechanism 16 includes a controller 165 and a drive circuit 167. The drive circuit 167 is electrically connected to the stator windings U, V, and W of the motor 121, and is used to transfer the current from the battery pack 13 to the stator windings U, V, and W to drive the motor 121 to rotate. In one embodiment, the drive circuit 167 includes a plurality of switching elements Q1, Q2, Q3, Q4, Q5, and Q6. The gate terminal of each switching element is electrically connected to the controller 17 to receive a control signal from the controller 17. The drain or source terminal of each switching element is connected to the stator windings U, V, and W of the motor 121. The switching elements Q1-Q6 receive the control signal from the controller 17 and change their respective conduction states, thereby changing the current loaded by the battery pack 13 on the stator windings U, V, and W of the motor 121. In one embodiment, the drive circuit 167 may be a three-phase bridge driver circuit comprising six controllable semiconductor power devices, such as field-effect transistors (FETs), bipolar junction transistors (BJTs), insulated-gate bipolar transistors (IGBTs), etc. It is understood that the aforementioned switching elements may also be any other type of solid-state switch, such as an insulated-gate bipolar transistor (IGBT), a bipolar junction transistor (BJT), etc.

[0062] In this embodiment, controller 165 is used to control motor 121. Controller 165 is mounted on a control circuit board, which includes a printed circuit board (PCB) and a flexible printed circuit board (FPC). Controller 165 employs a dedicated control chip, such as a microcontroller or microcontroller unit (MCU). Specifically, controller 165 controls the on / off state of the switching elements in drive circuit 167 through the control chip. In some embodiments, controller 165 controls the ratio between the on and off times of the drive switch based on a pulse width modulation (PWM) signal. It should be noted that the control chip can be integrated into controller 165 or can be set independently of controller 165. The structural relationship between the drive chip and controller 165 is not limited in this embodiment.

[0063] In this embodiment, the rotational speed of motor 121 is adjusted according to the trigger travel of the trigger switch. In this embodiment, the start switch 1522 is coupled to a sliding rheostat; different trigger travels of trigger 1521 result in different analog signals output by the sliding rheostat. The trigger travel of trigger 1521 is positively correlated with the duty cycle of the PWM signal of motor 12, and the duty cycle of the PWM signal is positively correlated with the rotational speed of motor 12. When the trigger travel of trigger 1521 is small, the duty cycle of the PWM signal is also small, and at this time, the rotational speed of motor 12 is also small. In some embodiments, the handheld excavator stores a mapping relationship between the trigger travel of trigger 1521 and the PWM signal; this mapping relationship can be linear, or it can be non-linear.

[0064] like Figure 6 As shown, the control mechanism 16 is disposed circumferentially on the motor 121. In this embodiment, the control mechanism 16 and the battery pack 13 are respectively disposed on both sides of the motor 121. Optionally, the battery pack 13 is disposed on the rear side of the motor 121, and the control mechanism 16 is disposed on the front side of the motor 121. Optionally, the control mechanism 16 is disposed near the output end of the motor 121. In the direction of the motor axis 102, the control mechanism 16 and the transmission assembly 14 have essentially no overlapping portion. Optionally, in the direction of the motor axis 102, the control mechanism 16 and the stator of the motor 121 have essentially no overlapping portion. This is to reduce heat transfer between the motor, the transmission assembly, and the control mechanism. In this embodiment, the housing 122 has an air inlet 1221 at a position corresponding to the control mechanism 16.

[0065] In this embodiment, the control mechanism 16 further includes a cable 16a. The cable 16a extends out of the drive mechanism through a hole in the side wall of the air guide shroud 123. After passing through the first support part 111, the cable 16a enters the handle frame 112 and connects to the start switch in the handle assembly 15. This achieves electrical connection between the start switch 1522 and the control mechanism 16. In this embodiment, the handle frame 112 has a hollow tube structure, and the connection between the first support part 111 and the main handle frame 113 forms a pipe structure to allow the cable 16a to enter. Optionally, the cable 16a is fixed to the first support part 111 by a cable clip 1111.

[0066] In this embodiment, a torque transmission component is provided on the housing. The torque-bearing component is a boss, and the torque transmission component is a groove that mates with the boss.

[0067] In other alternative embodiments, the housing 122 is provided with two or more battery connection portions 126 for connecting two or more battery packs 13 with a nominal voltage greater than 40V and less than 80V.

[0068] The housing 122 may also provide a user interface for operator control and / or configuration of the power tool 100. The user interface may include one or more of indicators, displays, mechanical buttons, membrane buttons, and touchscreens. The housing may also have an electrical interface for electrical communication with one or more sensors disposed externally to the housing, or a communication interface for communication connection. In some embodiments, the user uses external devices, including smartphones, tablets, laptops, and smart wearable devices, to set control parameters and receive operational status feedback for the handheld excavator via Bluetooth, WLAN, or wireless transmission.

[0069] The drill rod mechanism includes a drill shaft 21 and an auger blade 22 mounted on the drill shaft 21. When encountering rocks or hard rock (such as granite or limestone) on hard ground or during drilling, the auger blade 22 may fail to advance downwards and may backlash, resulting in a counter-torque applied to the operator of the handheld digging tool 100. If the operator does not grip the handle of the handheld digging tool 100 firmly enough, when backlash occurs and the motor 121 remains operational, the drill rod mechanism stalls and the main unit 1 begins to rotate in the opposite direction. This is particularly dangerous for the operator, as their hand remains on the handle. In some operating conditions, when encountering rocks and being unable to work, a sudden increase in output torque due to load may occur, potentially causing the machine handle to slip out of the operator's control if the operator is unprepared, and the rotating handle could strike and injure the operator. Therefore, a device is needed to prevent injury to the operator from backlash.

[0070] In this embodiment, the controller 165 is configured to limit the torque output of the motor 121 when the load parameter of the drill rod mechanism reaches a first threshold and the rotational displacement parameter of the support mechanism 11 is detected to reach a second threshold.

[0071] In this embodiment, the host 1 is adapted to a first drill rod mechanism 2 with a first function and a second drill rod mechanism 3 with a second function. The first drill rod mechanism 2 is suitable for substrates such as soil, sand, walls, and wood. The second drill rod mechanism 3 is suitable for drilling into ice. When adapting the two drill rod mechanisms, the working conditions are different, and the conditions and manifestations of backlash also differ. In this embodiment, the load parameters of the drill rod mechanism can characterize the stress state of the drill rod mechanism, and the rotational displacement parameters of the support mechanism 11 can characterize the tilting of the support mechanism 11 or the host 1, abnormal displacement on the physical movement plane, etc. By coordinating different principles, they can adapt to more working conditions. Moreover, the detection and confirmation methods of the two methods can mutually correct the detection results, making the start-up of the process for limiting motor torque more accurate and safer.

[0072] The load parameters characterize the output torque of the drill pipe mechanism and include any one of the motor current-related parameters and the motor speed-related parameters. The rotational displacement parameters of the support mechanism include at least one of the following: the angle of rotation of the support mechanism about the first axis, the change in angle, the angular acceleration, and the change in angular acceleration.

[0073] The load parameters are mainly the electrical parameters of motor 121. The position parameters and position change parameters are mainly the physical parameters of the position of the host 1. Simultaneously, based on different principles, they work together to limit the torque output of motor 121 when backlash occurs.

[0074] In this embodiment, limiting the torque output of motor 121 means braking motor 121 immediately or after a predetermined time period. In some embodiments, "limiting the torque output of motor 121" means that the power supply to motor 121 is not cut off, but reduced. Therefore, the output torque of motor 121 is reduced. In some embodiments, "limiting the torque output of motor 121" means that controller 165 sends a stop signal to motor 121, but the power supply to motor 121 is not cut off.

[0075] like Figures 9 to 10As shown, the control mechanism 16 includes a first detection component 161 for detecting the load parameters of the drill pipe mechanism. In some embodiments, the first detection component 161 detects motor current-related parameters. It should be explained that motor current-related parameters include the motor current and parameters obtained by calculation of the motor current. Optionally, the first detection component 161 includes a current sensor. Optionally, the first detection component 161 can be implemented as a current sensing resistor, operational amplifier, converter, or other similar electronic equipment. In some embodiments, the first detection component 161 detects motor speed-related parameters. It should be explained that motor speed-related parameters include directly detecting the motor speed and obtaining the motor speed from other motor parameters, such as motor commutation parameters, demagnetization time, etc. Optionally, the motor speed is detected by a magnetic ring, magnet, or photoelectric encoder, or by an inductor, Hall sensor, or photoelectric sensor. The specific value of the first threshold is set according to the specific product and is not specifically limited in this application. In some embodiments, the load of the drill pipe mechanism is positively correlated with the motor current, that is, the greater the load of the drill pipe mechanism, the greater the motor current. Optionally, the load of the drill pipe mechanism is linearly correlated with the motor current. Optionally, the load on the drill pipe mechanism is non-linearly related to the motor current. In some embodiments, the load on the drill pipe mechanism is inversely proportional to the motor speed, i.e., a larger load on the drill pipe mechanism results in a lower motor speed. Optionally, the load on the drill pipe mechanism is linearly related to the motor speed. Optionally, the load on the drill pipe mechanism is non-linearly related to the motor speed.

[0076] The control mechanism 16 also includes a second detection component 162. The second detection component 162 is used to detect the rotational displacement parameters of the support mechanism 11. The rotational displacement parameters of the support mechanism 11 include at least one of the following: the angle of rotation of the support mechanism about the first axis, the change in the angle, the angular acceleration, and the change in the angular acceleration.

[0077] The second detection component 162 can be a position sensor, used to acquire rotational displacement parameter information of the support mechanism when the motor starts. Optionally, the second detection component 162 can be a photodiode sensor, a magnetic sensor, or a potentiometer. The second detection component 162 can also be a rotation sensor, specifically a gyroscope sensor. The gyroscope sensor can be a single-axis, two-axis, or three-axis microelectromechanical system (MEMS) sensor or a rotational sensor. Other types of sensors are also disclosed in this application. In some embodiments, the gyroscope sensor detects the rotational acceleration of the support mechanism 11 or the drive mechanism 12. Taking angular acceleration detection as an example, if any acceleration component (or composite) exceeds a certain threshold and persists for a certain period of time, it is determined that a backlash has occurred, and the motor torque output is limited. In some embodiments, if two acceleration components of the rotating plane of the host exceed a certain threshold and persist for a certain period of time, a backlash is determined, and the motor torque output is limited.

[0078] The second detection component is placed on top of or on the side of the motor.

[0079] The controller 165 is configured to stop the motor 121 after a preset time period when the motor current-related parameters meet the motor current protection threshold. During this preset time period, the speed of the motor 121 linearly decreases from its current speed to the stop. In some embodiments, the speed of the motor 121 decreases uniformly from its current speed to the stop during the preset time period. In some embodiments, the speed of the motor 121 decreases from its current speed through a quadratic curve to the stop during the preset time period. When an overcurrent occurs in the motor 121, the motor 121 linearly decreases to the stop within the preset time period. This ensures the safety of the motor 121 and the operator.

[0080] The handheld excavator 100 also includes a brake switch. When the brake switch is triggered, the motor 121 stops rotating. In this embodiment, the power supply circuit for the motor is disconnected when the brake switch is triggered. The handheld excavator 100 also includes a start switch. When the start switch is triggered, the motor 121 starts rotating. In this embodiment, the brake switch and the start switch are two states of a single switch unit 152, i.e., a trigger. Of course, in some embodiments, there may be two independent switches.

[0081] In this embodiment, the controller 165 is configured to limit the torque output of the motor 121 when the change in the rotational speed of the motor 121 reaches a preset change threshold when the brake switch is not triggered. Optionally, the torque output of the motor 121 is limited when the change in the rotational speed of the motor 121 reaches the preset change threshold within a second preset time period. That is, when the rotational speed of the motor 121 changes abruptly or abnormally, the torque output of the motor 121 is limited to ensure the safety of the motor 121.

[0082] The second detection component 162 is also used to detect the pressure parameter of the support mechanism 11 along the first axis 101. The controller 165 is further configured to start the motor 121 to drive the drill rod mechanism when the pressure parameter of the support mechanism 11 along the first axis 101 reaches a starting threshold and the motor 121 has power supply. That is, when the power supply circuit is connected and the pressure parameter of the support mechanism 11 along the first axis 101 reaches the starting threshold, the controller sends a start signal to the motor. This ensures the motor starts when needed, preventing accidental start-up. Furthermore, adding a pressure parameter check also protects the machine.

[0083] Optionally, the pressure parameters include at least one of the following: the downward displacement value of the support mechanism 11 along the first axis 101, the downward pressure value of the support mechanism 11 along the first axis 101, and the reaction force value of the drill pipe mechanism on the support mechanism 11 along the first axis 101.

[0084] Optionally, the handheld excavator 100 also includes an environmental monitoring component 164 for detecting power lines, gas pipelines, and water pipes in the working environment. This ensures the protection of public facilities during drilling and excavation, and guarantees public safety.

[0085] The above detection components can be used individually or in combination using several of the technologies.

[0086] like Figure 11 As shown, a control method for a handheld excavating tool includes the following steps:

[0087] S510. Determine that the load parameters of the drill pipe mechanism have reached the first threshold.

[0088] The load parameters characterize the output torque of the drill pipe mechanism and include any one of motor current-related parameters and motor speed-related parameters. The first detection component 161 is used to detect the load parameters of the drill pipe mechanism. Optionally, the first detection component 161 detects motor current-related parameters. The first detection component 161 includes a current sensor. Optionally, the first detection component 161 can be implemented using a current sensing resistor, operational amplifier, converter, or other similar electronic equipment. Optionally, the first detection component 161 detects motor speed-related parameters. It should be explained that motor speed-related parameters include directly detecting the motor speed and obtaining the motor speed from other motor parameters through calculation, such as motor commutation parameters and demagnetization time. Optionally, the motor speed is detected by a magnetic ring, magnet, or photoelectric encoder, using an inductor, Hall sensor, or photoelectric sensor. Optionally, the specific value of the first threshold is set according to the specific product and is not specifically limited in this application.

[0089] S520. Detect the rotational displacement parameters of the support mechanism.

[0090] The rotational displacement parameters of the support mechanism 11 include at least one of the following: the angle of rotation of the support mechanism about the first axis, the change in angle, angular acceleration, and the change in angular acceleration. The second detection component 162 can be a position sensor, used to acquire the rotational displacement parameter information of the support mechanism when the motor is started.

[0091] S530, Determine that the rotational displacement parameter of the support mechanism reaches the second threshold.

[0092] Taking angular acceleration detection as an example, the second detection component detects any acceleration component (or its composite) exceeding a certain threshold for a certain period of time, determines that a backlash has occurred, and limits the motor torque output. In some embodiments, two acceleration components of the host's rotational plane exceeding a certain threshold for a certain period of time are selected to determine a backlash.

[0093] S540, Limit the torque output of the motor.

[0094] The torque output of motor 121 is limited to brake motor 121 immediately or after a predetermined period of time. In some embodiments, "limiting the torque output of motor 121" means that the power supply to motor 121 is not cut off, but reduced. Therefore, the output torque of motor 121 is reduced. In some embodiments, "limiting the torque output of motor 121" means that controller 165 sends a stop signal to motor 121, but the power supply to motor 121 is not cut off.

[0095] In this embodiment, the host 1 is adapted to a first drill rod mechanism 2 with a first function and a second drill rod mechanism 3 with a second function. The first drill rod mechanism 2 is suitable for substrates such as soil, sand, walls, and wood. The second drill rod mechanism 3 is suitable for drilling into ice. When adapting the two drill rod mechanisms, the working conditions are different, and the conditions and manifestations of backlash also differ. In this embodiment, the load parameters of the drill rod mechanism can characterize the stress state of the drill rod mechanism, and the rotational displacement parameters of the support mechanism 11 can characterize the tilting of the support mechanism 11 or the host 1, abnormal displacement on the physical movement plane, etc. By coordinating different principles, they can adapt to more working conditions. Moreover, the detection and confirmation methods of the two methods can mutually correct the detection results, making the start-up of the process for limiting motor torque more accurate and safer.

[0096] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that the above embodiments do not limit this application in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of this application.

Claims

1. A handheld digging tool, comprising: A drill rod mechanism for rotating about a first axis to perform drilling; The drill pipe mechanism includes: a first drill pipe mechanism having a first function and a second drill pipe mechanism having a second function; the working base materials of the first function and the second function are different; A drive mechanism, including a motor; the drive mechanism is used to drive the drill pipe mechanism to work; the drive mechanism is configured to be selectively connected to one of the first drill pipe mechanism and the second drill pipe mechanism. A support mechanism is provided to support the drive mechanism. A controller is used to control the operation of the motor; The controller is configured to limit the torque output of the motor when the load parameter of the drill rod mechanism reaches a first threshold and the rotational displacement parameter of the support mechanism is detected to reach a second threshold.

2. The handheld digging tool according to claim 1, characterized in that, The load parameters are used to characterize the torque of the drill pipe mechanism, and the load parameters include any one of the motor current-related parameters and the motor speed-related parameters.

3. The handheld digging tool according to claim 1, characterized in that, The rotational displacement parameters of the support mechanism include at least one of the following: the angle of rotation of the support mechanism about the first axis, the change value of the angle, the angular acceleration, and the change value of the angular acceleration.

4. The handheld digging tool according to claim 3, characterized in that, It also includes a position sensor for acquiring rotational displacement parameter information of the support mechanism when the motor is started.

5. The handheld digging tool according to claim 2, characterized in that, The controller is configured to control the motor to stop after a preset time when the motor current-related parameters meet the motor current protection threshold.

6. The handheld digging tool according to claim 5, characterized in that, The controller is configured to linearly reduce the speed of the motor from its current speed to a stop within a preset time period.

7. The handheld digging tool according to claim 1, characterized in that, It also includes a brake switch for stopping the motor when triggered. The controller is configured to limit the torque output of the motor when the change in the motor speed reaches a preset change threshold when the brake switch is not triggered.

8. The handheld digging tool according to claim 1, characterized in that, The controller is also configured to start the motor to drive the drill rod mechanism to move when the pressure parameter of the support mechanism along the first axis reaches the start threshold and the motor has power supply.

9. The handheld digging tool according to claim 8, characterized in that, The pressure parameters include at least one of the following: the displacement value of the support mechanism moving downward along the first axis, the downward pressure value of the support mechanism along the first axis, and the reaction force value of the support mechanism from the drill pipe mechanism along the first axis.

10. The handheld digging tool according to claim 1, characterized in that, It also includes environmental monitoring components for monitoring power lines, gas pipelines, and water pipes in the working environment.

11. The handheld digging tool according to claim 1, characterized in that, The drive mechanism drives the first drill rod mechanism to operate at a first output speed or the first drill rod mechanism to operate at a second output speed.

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