Impact tool

Abstract

The invention discloses an impact tool which comprises a motor, an output shaft, an impact mechanism and a transmission mechanism, the transmission mechanism is configured to transmit torque output by a driving shaft to the output shaft, and the transmission mechanism comprises multiple stages of transmission assemblies; the direct-current power supply at least supplies power to the motor, and the nominal voltage of the direct-current power supply is smaller than 18V; and the fastening torque of the output shaft to a workpiece is greater than or equal to 170N. M. A large torque impact tool powered using a low nominal voltage is provided.

Description

Technical Field

[0001] The present application relates to the field of power tools, and particularly to an impact tool. Background Art

[0002] An impact tool refers to a tool that can output a rotational motion at a certain impact frequency. Common impact tools include impact wrenches, impact screwdrivers, impact drills, etc. Impact wrenches are usually used for screwing bolts and nuts, impact screwdrivers are usually used for loosening or tightening screws, and impact drills are usually used for impact drilling.

[0003] In order to output a rotational motion with a certain impact frequency, an impact tool generally includes an output assembly for outputting a rotational force and an impact mechanism for periodically impacting the output assembly.

[0004] In related technology products, the higher the impact torque output of an impact tool, the higher the output power and output torque of the DC power supply required.

[0005] This section provides background information related to the present application, and these background information are not necessarily prior art. This section provides background information related to the present application, and these background information are not necessarily prior art. Summary of the Invention

[0006] An object of the present application is to solve or at least mitigate part or all of the above problems. To this end, an object of the present application is to provide a high-torque impact tool powered by a low nominal voltage.

[0007] To achieve the above object, the present application adopts the following technical solutions: An impact tool, comprising: a motor including a drive shaft rotating about a first axis; an output shaft including an output axis defined by itself, the output shaft rotating about the output axis to output power; an impact mechanism applying an impact force to the output shaft, the impact mechanism including an impact block driven by the motor and an anvil cooperating with the impact block and being impacted by the impact block; a transmission mechanism configured to transmit the torque output by the drive shaft to the output shaft, the transmission mechanism including a multi-stage transmission assembly; a DC power supply supplying power to at least the motor, the nominal voltage of the DC power supply being less than 18V; wherein, the tightening torque of the output shaft on the workpiece is greater than or equal to 170 N·m.

[0008] In some embodiments, the multi-stage transmission assembly includes at least two planetary gear reduction assemblies.

[0009] In some embodiments, the multi-stage transmission assembly includes: a first planet carrier disposed in front of the motor, a first planetary gear supported by the first planet carrier; a second planet carrier disposed in front of the first planet carrier; a second planetary gear supported by the second planet carrier; and an internal gear ring for causing the second planetary gear to perform planetary motion.

[0010] In some embodiments, the impact mechanism further includes a main shaft connecting the impact block and the drive shaft and a first bearing supporting the rotation of the main shaft, and the first bearing restricts the axial displacement of the internal gear ring.

[0011] In some embodiments, the ratio of the rotational speed of the drive shaft to the rotational speed of the main shaft is substantially a constant value.

[0012] In some embodiments, the speed ratio from the drive shaft to the main shaft is greater than or equal to 9:1.

[0013] In some embodiments, the internal gear ring causes the first planetary gear and the second planetary gear to perform planetary motion respectively.

[0014] In some embodiments, the maximum rotational speed of the output shaft is less than or equal to 3000 rpm.

[0015] In some embodiments, the nominal voltage of the DC power supply is greater than or equal to 3V and less than or equal to 9V.

[0016] An impact tool, comprising a motor including a drive shaft rotating about a first axis; an output shaft including an output axis defined by itself, the output shaft rotating about the output axis to output power; an impact mechanism applying an impact force to the output shaft, the impact mechanism including an impact block driven by the motor and an anvil cooperating with the impact block and being impacted by the impact block; a transmission mechanism configured to transmit the torque output by the drive shaft to the output shaft; a DC power supply supplying power to at least the motor, the nominal voltage of the DC power supply being greater than or equal to 3V and less than or equal to 9V; wherein the tightening torque of the output shaft on the workpiece is greater than or equal to 170 N·m.

[0017] An impact tool, comprising: a motor including a drive shaft rotating about a first axis; an output shaft including an output axis defined by itself, the output shaft rotating about the output axis to output power; an impact mechanism applying an impact force to the output shaft, the impact mechanism including an impact block driven by the motor, an anvil cooperating with the impact block and being impacted by the impact block, and a main shaft connecting the impact block and the drive shaft; a transmission mechanism configured to transmit the torque output by the drive shaft to the main shaft; the speed ratio from the drive shaft to the main shaft being greater than or equal to 9:1; a DC power supply supplying power to at least the motor, the nominal voltage of the DC power supply being greater than or equal to 3V and less than or equal to 9V; wherein the tightening torque of the output shaft on the workpiece is greater than or equal to 170 N·m.

[0018] The advantages of the present application are as follows: By providing a transmission mechanism with a high speed ratio or multi-stage transmission, the impact tool can output a large torque even when using a DC power supply with a low nominal voltage, ensuring the use safety and service life of the impact tool and expanding the applicable range of the DC power supply for the impact tool. Using a DC power supply with a low nominal voltage can also reduce the product cost and lighten the product weight. Brief Description of the Drawings

[0019] Figure 1 is a structural diagram of an embodiment in the present application; Figure 2 is a sectional view of an embodiment in the present application; Figure 3 is a schematic diagram of an exploded view of an embodiment in the present application; Figure 4 is a schematic diagram of a partial exploded view of an embodiment in the present application; Figure 5 is a schematic diagram of a partial exploded view of an embodiment in the present application; Figure 6 is a schematic diagram of another perspective of a partial exploded view of an embodiment in the present application; Figure 7 is Figure 6 a structural diagram of some components in; Figure 8 is Figure 7 a schematic diagram of another perspective of; Figure 9 is Figure 8 a sectional view A - A of the exploded view of the component and the internal gear ring component in; Figure 10 is a partial exploded view of a battery pack of an embodiment in the present application; Figure 11 is a partial exploded view of a battery pack of an embodiment in the present application. Detailed Description of the Embodiments

[0020] Before explaining any embodiment of the present application in detail, it should be understood that the present application is not limited to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0021] In the present application, the terms "comprising", "including", "having" or any other variation thereof are intended to cover non - exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising that element.

[0022] In the present application, the term "and / or" describes the associative relationship of associated objects and represents three possible relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, in the present application, the character " / " generally represents an "and / or" relationship between the associated objects before and after.

[0023] In this application, the terms "connected", "combined", "coupled", "installed" can be direct connection, combination, coupling or installation, or can be indirect connection, combination, coupling or installation. Among them, for example, direct connection means that two parts or components are connected together without setting intermediate parts, and indirect connection means that two parts or components are respectively connected to at least one intermediate part, and these two parts or components are connected through the intermediate part. In addition, "connection" and "coupling" are not limited to physical or mechanical connection or coupling, and can include electrical connection or coupling.

[0024] In this application, those of ordinary skill in the art will understand that relative terms used in combination with a quantity or condition (such as "about", "approximately", "substantially", etc.) are intended to include the stated value 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 caused by manufacturing, assembly, use, etc. associated with a particular value. Such terms should also be considered to disclose a range defined by the absolute values of the two endpoints. The relative term may refer to a plus or minus of a certain percentage (such as 1%, 5%, 10% or more) of the indicated value. A numerical value without using a relative term should also be disclosed as a specific value with a tolerance. In addition, when expressing a relative angular positional relationship (such as substantially parallel, substantially perpendicular), "substantially" may refer to a plus or minus a certain number of degrees (such as 1 degree, 5 degrees, 10 degrees or more) based on the indicated angle.

[0025] In this application, those of ordinary skill in the art will understand that the functions performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the functions performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0026] In this application, the directional terms such as "upper", "lower", "left", "right", "front", "rear", etc. are described based on the orientation and positional relationship shown in the drawings, and should not be construed as a limitation on the embodiments of this application. In addition, in the context, it should also be understood that when it is mentioned that one element is connected "above" or "below" another element, it can not only be directly connected "above" or "below" another element, but also be indirectly connected "above" or "below" another element through an intermediate element. It should also be understood that the directional terms such as upper side, lower side, left side, right side, front side, rear side, etc. not only represent the positive direction, but can also be understood as the side direction. For example, the lower side can include directly below, lower left, lower right, lower front, and lower rear, etc.

[0027] To clearly illustrate the technical solution of this application, the upper side, lower side, front side and rear side as shown in Figure 1 are also defined.

[0028] As Figures 1 to 2 shown, the impact tool of the first embodiment of the present application is an impact wrench 100. It can be understood that the impact tool is a rotary tool. In other alternative embodiments, different working accessories can be installed on the rotary tool, and through these different working accessories, the impact tool can be other impact tools such as an impact screwdriver, an impact drill, etc.

[0029] As Figure 1 shown, the impact wrench 100 of the first embodiment of the present application includes a power supply. The power supply is used to supply electrical energy to the impact wrench 100. In this embodiment, the power supply includes a DC power supply 30. For example, the DC power supply 30 is a battery pack, and the battery pack cooperates with a corresponding power circuit to supply power to corresponding components in the impact wrench 100. Those skilled in the art should understand that the power supply is not limited to the scenario of using a battery pack, and can also supply power to the corresponding components in the machine through mains electricity, an AC power supply, and cooperate with corresponding rectification, filtering, and voltage regulation circuits. In this embodiment, the DC power supply 30 is specifically set as a battery pack, and the battery pack 30 will be used to replace the DC power supply hereinafter, but it cannot be used as a limitation to the present application.

[0030] As Figures 1 to 5 shown, the impact wrench 100 includes a housing 11, a motor 12, an output mechanism 13, a transmission mechanism 14, and an impact mechanism 15. The motor 12 includes a drive shaft 121 that rotates about a first axis 101. In this embodiment, the motor 12 is specifically set as an electric motor, and the electric motor 12 will be used to replace the motor hereinafter, but it cannot be used as a limitation to the present application. In this embodiment, the electric motor 12 includes a stator assembly 122 and a rotor assembly 123. The rotor assembly 123 forms or is connected to a drive shaft 121 that rotates about the first axis 101. In this embodiment, the electric motor 12 is an inner rotor brushless motor. In other alternative embodiments, the electric motor 12 is an outer rotor brushless motor. For an inner rotor motor, the stator assembly 122 is sleeved outside the rotor assembly 123. For an outer rotor motor, the rotor assembly 123 is sleeved outside the stator assembly 122. In this embodiment, the brushless motor is set as a three-phase brushless motor. It can be understood that the motor is not limited to a three-phase brushless motor, and can also be other types of DC motors, which does not affect the substantial content of the present application.

[0031] Among them, the housing 11 includes a motor housing 111 for accommodating the motor 12 and an output housing 112 for accommodating at least a part of the output mechanism 13. The output housing 112 is connected to the front end of the motor housing 111. The housing 11 also forms or is connected with a holding part 113 for the user to operate. The holding part 113 and the motor housing 111 form a T-shaped or L-shaped structure, which is convenient for the user to hold and operate. One end of the holding part 113 is connected with a battery pack 30. The battery pack 30 is detachably connected to the holding part 113.

[0032] The output mechanism 13 includes an output shaft 131 for connecting a working accessory and driving the working accessory to rotate. A clamping assembly is provided at the front end of the output shaft 131, which can clamp the corresponding working accessories, such as a bit, a drill bit, a socket, etc., when realizing different functions.

[0033] The output shaft 131 is used to output power, and the output shaft 131 rotates about the output axis 102. In this embodiment, the first axis 101 coincides with the output axis 102. In other alternative embodiments, the output axis 102 and the first axis 101 are arranged at a certain angle. In other alternative embodiments, the first axis 101 and the output axis 102 are parallel to each other but not coincident.

[0034] As Figures 2 to 5 shown, the impact mechanism 15 is used to provide an impact force to the output shaft 131. The impact mechanism 15 includes a main shaft 151, an impact block 152 sleeved on the outer periphery of the main shaft 151, an anvil 153 arranged at the front end of the impact block 152, and an elastic element 154. Among them, the anvil 153 is connected to the output shaft 131. In this embodiment, the anvil 153 includes an anvil base 1531, and the output shaft 131 is formed or connected to the front end of the anvil base 1531. It can be understood that the anvil base 1531 and the output shaft 131 can be integrally formed or separate independent parts.

[0035] The impact block 152 is driven by the drive shaft 121 to rotate. The anvil base 1531 cooperates with the impact block 152 and is struck by it. The main shaft 151 connects the impact block 152 and the drive shaft 121. In this embodiment, the drive shaft 121 drives the main shaft 151, and the main shaft 151 drives the impact block 152 to rotate.

[0036] The impact block 152 includes an impact block body 1521, and a pair of first end teeth 1523 are radially symmetrically protruded on the front end face of the impact block body 1521. A pair of second end teeth 1532 are radially symmetrically protruded on the rear end face of the anvil 1531 opposite to the impact block 152. The output shaft 131 extends out of the output housing 112. The impact block 152 is supported on the main shaft 151 and rotates integrally with the main shaft 151 and can reciprocally slide relative to the main shaft 151 in the axial direction of the main shaft. In this embodiment, the axis of the main shaft 151 coincides with the axis of the drive shaft 121. Therefore, the impact block 152 reciprocally slides and rotates relative to the main shaft 151 along the direction of the first axis 101. In other alternative embodiments, the axis of the main shaft can be parallel to but not coincide with the axis of the drive shaft 121, or the axis of the main shaft forms a certain angle with the axis of the drive shaft 121.

[0037] The elastic element 154 provides a force for the impact block 152 to make it close to the anvil 153. In this embodiment, the elastic element 154 is a helical spring.

[0038] During the working process of the impact wrench 100, the impact block 152 rotates integrally with the main shaft 151 and reciprocates back and forth relative to the main shaft 151 along the direction of the first axis 101 with a specified stroke. A pair of first ball grooves 1522 which open forward and extend backward in the front-rear direction are further provided on the front end face of the impact block body 1521. A pair of V-shaped second ball grooves 1511 are further formed on the outer surface of the main shaft 151. Both the first ball grooves 1522 and the second ball grooves 1511 have semi-circular groove bottoms. The impact mechanism 15 further includes rolling balls 155. The rolling balls 155 straddle the first ball grooves 1522 and the second ball grooves 1511, so that the impact block 152 is connected to the main shaft 151 and moves together. In this embodiment, the rolling balls 155 are steel balls.

[0039] In the related art, since inwardly recessed V-shaped grooves are respectively provided on the impact block and the main shaft, and thus a ball track is jointly formed, the rolling balls 155 are arranged between the impact block 152 and the main shaft 151 and are embedded into the ball track. Thus, the main shaft 151 can drive the impact block 152 to rotate through the rolling balls 155, and the impact block 152 drives the anvil 153 to rotate through the cooperation with the anvil 153 to further drive the output shaft 131 to rotate.

[0040] When the impact wrench 100 is unloaded, the impact mechanism 15 does not produce an impact. The impact mechanism 15 functions as a transmission to transfer the rotation of the motor 12 to the output shaft 131. When a load is applied to the impact wrench 100, the rotation of the output shaft 131 is obstructed. Due to the different magnitudes of the load, the rotational speed of the output shaft 131 may decrease or it may stop rotating completely. When the output shaft 131 stops rotating completely, the anvil 153 also stops rotating. Due to the circumferential limiting effect of the anvil 153 on the impact block 152, the impact block 152 also stops rotating. However, the main shaft 151 continues to rotate, which causes the rolling ball 155 to be squeezed and move along the ball track, thereby driving the impact block 152 to produce a displacement backward along the axis of the main shaft 151, and at the same time squeezing the elastic element 154 until the anvil 153 is completely disengaged from the impact block 152. The main shaft 151 drives the impact block 152 to rotate at a certain rotational speed, and the elastic element 154 rebounds axially. The relative rotational speed between the impact block 152 and the anvil 153 is the rotational speed of the impact block 152. When the impact block 152 rotates to contact the anvil 153, an impact force will be applied to the anvil 153. Under the action of this impact force, the output shaft 131 overcomes the load and continues to rotate a certain angle. After that, the output shaft 131 stops rotating again, repeating the above process. Due to the sufficiently high impact frequency, a relatively continuous impact force will be generated on the output shaft 131, thereby enabling the working accessory to continue working.

[0041] As Figures 1 to 3 shown, the impact wrench 100 further includes a main switch 161 and a switching portion 163. Among them, the main switch 161 is a trigger switch. The trigger switch is arranged on the holding portion 113 for the user to operate. The rotational speed of the motor 12 is adjusted according to the trigger stroke of the trigger switch. In this embodiment, the trigger switch is coupled to a sliding rheostat 162. Different trigger strokes of the trigger switch result in different analog signals output by the sliding rheostat 162. The trigger stroke of the trigger switch has a positive correlation with the duty cycle of the Pulse Width Modulation (PWM) signal of the motor 12, and the duty cycle of the PWM signal has a positive correlation with the rotational speed of the motor 12. When the trigger stroke of the trigger switch is small, the duty cycle of the PWM signal is also small. At this time, the rotational speed of the motor 12 is also small. In some embodiments, a mapping relationship between the trigger stroke of the trigger switch and the PWM signal is stored in the impact wrench. This mapping relationship can be linear or non-linear. The embodiments of the present application do not limit this.

[0042] The switching portion 163 is arranged on the upper side of the trigger switch. The switching portion 163 is configured to be operated to set the rotational direction of the motor to the forward rotation direction for tightening the fastener or the reverse rotation direction for loosening the fastener.

[0043] As Figures 2 to 5As shown, the transmission mechanism 14 is configured to transmit the torque output by the drive shaft 121 to the output shaft 131. In this embodiment, the transmission mechanism 14 is disposed between the motor 12 and the impact mechanism 15 for achieving power transmission between the drive shaft 121 and the main shaft 151.

[0044] The transmission mechanism 14 reduces the output speed and increases the torque of the drive shaft 121 so that when the load on the output shaft 131 exceeds the threshold, the main shaft 151 can drive the impact block 152 to compress the elastic element 154 and move backward. In this embodiment, the nominal voltage of the battery pack 30 is less than 18V, that is, when the motor 12 is powered by the battery pack 30 with a nominal voltage less than 18V, the fastening torque of the output shaft 131 of the impact wrench 100 on the workpiece is greater than or equal to 170 N·m. It can be understood that the output shaft 131 transmits continuous rotational impact on the workpiece, and when the battery pack 30 supplies a nominal voltage less than 18V to the motor 12, a fastening torque of at least 170 N·m is generated. Herein, the "fastening torque" refers to the torque applied to the fastener in the direction of increasing tension (i.e., in the tightening direction). In this embodiment, the transmission ratio provided by the transmission mechanism 14 from the drive shaft 121 to the main shaft 151 is greater than or equal to 9:1 so that the output speed of the motor 12 adapted to a nominal voltage less than 18V can be reduced to a speed suitable for the impact mechanism 15 to generate impact. In this embodiment, the transmission mechanism 14 includes a multi-stage transmission assembly 140 so that the transmission ratio from the drive shaft 121 to the main shaft 151 is greater than or equal to 9:1. In some embodiments, the nominal voltage of the battery pack 30 is greater than or equal to 3V and less than or equal to 11V. In some embodiments, the nominal voltage of the battery pack 30 is greater than or equal to 3V and less than or equal to 9V.

[0045] According to the related technology, the output torque of the motor 12 is positively correlated with the power of the motor 12, and the output torque of the motor 12 is negatively correlated with the output speed of the motor 12. And the power of the motor 12 is the product of the voltage applied to the motor 12 and the bus current. Thus, when the voltage applied to the motor 12 is reduced, if it is required that the motor 12 outputs the same output torque or the same output power, at this time, it is necessary to increase the bus current, which is equivalent to compensating for the gap caused by the reduced voltage by increasing the bus current. On the one hand, this increases the cost of the motor 12 itself. On the other hand, since a switching element is used in the impact tool, the duty ratio between the on-time and the off-time of the driving switch is controlled based on a Pulse Width Modulation (PWM) signal to control the motion state of the motor 12. Therefore, when the bus current of the motor 12 is increased, the requirements for the switching element are also increased, which not only increases the cost during use, but also has requirements for heat dissipation and lifespan. Therefore, in the prior art, for an impact tool whose fastening torque of the output shaft 131 on the workpiece is greater than or equal to 170 N·m, it is basically impossible to be powered by a battery pack with a nominal voltage less than 18V. Among them, the driving switch includes controllable semiconductor power devices (such as Field Effect Transistor (FET), Bipolar Junction Transistor (BJT), Insulated Gate Bipolar Transistor (IGBT), etc.), or Insulated Gate Bipolar Transistor (IGBT), Bipolar Junction Transistor (BJT), etc.

[0046] In this application, to ensure the usability and safety of the components in the motor 12 and its related control circuit. The impact tool uses a battery pack with a nominal voltage less than 18V to supply power to the motor 12, and maintains the output torque, output speed or output power of the motor 12 under the power supply condition of the nominal voltage less than 18V, and uses the method of increasing the gear ratio of the transmission mechanism 14 to keep the output torque output to the impact mechanism 15 at the original level (when the nominal voltage of the power supply battery pack is greater than or equal to 18V). Among them, in this embodiment, the gear ratio provided by the transmission mechanism 14 from the drive shaft 121 to the main shaft 151 is greater than or equal to 9:1. In some embodiments, the gear ratio provided by the transmission mechanism 14 from the drive shaft 121 to the main shaft 151 is greater than or equal to 9.5:1, 10:1, 10.5:1, 11:1, 11.5:1, 12:1. In some embodiments, the gear ratio provided by the transmission mechanism 14 from the drive shaft 121 to the main shaft 151 is greater than or equal to 12:1 and less than or equal to 14:1.

[0047] In this embodiment, the tightening torque of the output shaft 131 of the impact wrench 100 on the workpiece is greater than or equal to 170 N·m. In some embodiments, the tightening torque of the output shaft 131 of the impact wrench 100 on the workpiece is greater than or equal to 180 N·m. The tightening torque of the output shaft 131 of the impact wrench 100 on the workpiece is greater than or equal to 190 N·m. The tightening torque of the output shaft 131 of the impact wrench 100 on the workpiece is greater than or equal to 200 N·m. In some embodiments, the tightening torque of the output shaft 131 of the impact wrench 100 on the workpiece is greater than or equal to 210 N·m and less than or equal to 400 N·m.

[0048] In this embodiment, to ensure the usability and safety of the components in the motor 12 and its related control circuits, the impact tool uses a battery pack with a nominal voltage less than 18V to supply power to the motor 12, and maintains the output torque, output speed or output power of the motor 12 under the power supply of the nominal voltage less than 18V, and increases the torque output of the transmission mechanism 14 to keep the output torque output to the impact mechanism 15 at the original level (when the nominal voltage of the power supply battery pack is greater than or equal to 18V). Among them, in this embodiment, the transmission mechanism 14 includes a multi-stage transmission assembly 140. Optionally, the multi-stage transmission assembly 140 includes a multi-stage planetary transmission group. For example, the multi-stage transmission assembly 140 includes at least two-stage planetary gear reduction assemblies. Using multi-stage transmission to reduce speed and increase torque can ensure that the transmission mechanism 14 has a large speed ratio. Compared with using a single-stage transmission assembly, when achieving the same speed ratio, the multi-stage transmission assembly 140 has lower strength requirements for a single gear and is more beneficial to the service life of the transmission components.

[0049] As Figure 4 shown, the transmission mechanism 14 includes a housing assembly 14a, a first-stage planetary gear set 144 and a second-stage planetary gear set 145. It can be understood that in this embodiment, in order to ensure the compactness of the overall length of the impact wrench 100 as much as possible, two-stage planetary gear sets are provided. However, according to the actual requirements of the product, the transmission mechanism 14 can be provided with more than two-stage planetary gear sets. The above does not affect the substantial content of this application.

[0050] As Figures 2 - 4 shown, the first-stage planetary gear set 144 and the second-stage planetary gear set 145 are at least partially located in the housing assembly 14a. The first-stage planetary gear set 144 is close to the drive shaft 121, and the second-stage planetary gear set 145 is close to the main shaft 151. The planet carrier in the second-stage planetary gear set 145, which is the planetary gear transmission group closest to the impact mechanism 15 in the multi-stage planetary transmission group 140, forms or connects to the main shaft 151. In this embodiment, the speed ratio of the first-stage planetary gear set 144 is greater than 1, and the speed ratio of the second-stage planetary gear set 145 is greater than 1. In some embodiments, the speed ratio of at least one of the first-stage planetary gear set 144 and the second-stage planetary gear set 145 is greater than 1.

[0051] Optionally, the first-stage planetary gear set 144 includes: a first planetary gear 1441, a first planetary carrier 1442 for mounting the first planetary gear 1441, and a first internal gear ring 1443 meshing with the first planetary gear 1441. The drive shaft 121 forms or is connected to a first sun gear 122 that rotates at a first rotational speed. In this embodiment, the first sun gear 122 rotates coaxially with the drive shaft 121. Optionally, the first sun gear 122 rotates about the first axis 101. In other alternative embodiments, the first sun gear 122 is connected to the drive shaft 121.

[0052] The first sun gear 122 drives the first planetary gear 1441. The first planetary gear 1441 meshes with the first sun gear 122. A plurality of first planetary gears 1441 are provided, and all the plurality of first planetary gears 1441 mesh with the first sun gear 122. In this embodiment, three first planetary gears 1441 are evenly arranged circumferentially around the first axis 101.

[0053] The first sun gear 122 and the first planetary gear 1441 form a meshing tooth portion for transmitting power. The pitch diameter of the meshing tooth portion of the first sun gear 122 is smaller than the pitch diameter of the first-stage planetary gear set 144, such that the number of teeth of the meshing teeth of the first-stage planetary gear set 144 is greater than the number of teeth of the meshing tooth portion of the first sun gear 122. In some embodiments, the pitch diameter of the meshing tooth portion of the first sun gear 122 is greater than the pitch diameter of the first-stage planetary gear 1441. The pitch diameter of the meshing tooth portion of the first sun gear 122 is greater than or equal to 8 mm. The pitch diameter of the first planetary gear 1441 is less than 8 mm. Optionally, the pitch diameter of the meshing tooth portion of the first sun gear 122 is greater than or equal to 9 mm. Optionally, the pitch diameter of the meshing tooth portion of the first sun gear 122 is greater than or equal to 10 mm. Optionally, the pitch diameter of the meshing tooth portion of the first sun gear 122 is greater than or equal to 11 mm. Optionally, the pitch diameter of the meshing tooth portion of the first sun gear 122 is greater than or equal to 12 mm. Optionally, the pitch diameter of the meshing tooth portion of the first sun gear 122 is 13 mm. Optionally, the pitch diameter of the first planetary gear 1441 is 7.7 mm.

[0054] The first internal gear ring 1443 meshes with the peripheries of a plurality of first planet gears 1441. The first planet carrier 1442 includes a first transmission disk 1442a, a first support frame 1442b, and a first output portion. The first support frame 1442b and the first output portion are respectively formed on both sides of the first transmission disk 1442a. The first output portion rotates synchronously with the first transmission disk 1442a. The first support frame 1442b is inserted into the first planet gear 1441 and forms a rotational connection with the first planet gear 1441, so that the first planet gear 1441 can drive the first planet carrier 1442 to rotate around the first axis 101. Meshing teeth are formed on the circumferential side of the first output portion. The first output portion is used to mesh with the second-stage planet gear set 145, thereby realizing the transmission connection between the first-stage planet gear set 144 and the second-stage planet gear set 145. In this embodiment, the first output portion is the second sun gear 1444 of the second-stage planet gear set 145.

[0055] The second-stage planet gear set 145 includes: a second planet gear 1451, a second planet carrier 1452 for mounting the second planet gear 1451, and a second internal gear ring 1453 meshing with the second planet gear 1451. The second sun gear 1444 drives the second planet gear 1451. In this embodiment, the second sun gear 1444 rotates coaxially with the drive shaft 121. Optionally, the second sun gear 1444 rotates around the first axis 101. The second planet gear 1451 is arranged to mesh with the second sun gear 1444. A plurality of second planet gears 1451 are provided, and the plurality of second planet gears 1451 respectively mesh with the second sun gear 1444. In this embodiment, 3 second planet gears 1451 are evenly arranged in the circumferential direction around the first axis 101. The meshing relationship among the second planet gear 1451, the second planet carrier 1452, and the second internal gear ring 1453 is the same as the meshing relationship in the first-stage planet gear set 144, which is well known to those skilled in the art and will not be elaborated here.

[0056] The second planet carrier 1452 includes a second transmission disk 1452a and a second support frame 1452b. The second support frame 1452b is inserted into the second planet gear 1451 and forms a rotational connection with the second planet gear 1451, so that the second planet gear 1451 can drive the second transmission disk 1452a to rotate around the first axis 101. In this embodiment, the second transmission disk 1452a is formed at the rear end of the main shaft 151. The second planet gear 1451 drives the main shaft 151 to rotate through the second planet carrier 1452. In other alternative embodiments, the second transmission disk 1452a and the main shaft 151 can be independent components, and the second transmission disk 1452a is connected to the main shaft 151. As long as the second planet gear 1451 can drive the main shaft 151 to rotate.

[0057] In this embodiment, the ratio of the rotational speed of the drive shaft 121 to the rotational speed of the main shaft 151 is basically a constant value, that is to say, the transmission ratio from the drive shaft 121 to the main shaft 151 is basically a constant value. Optionally, the first internal gear ring 1443 and the second internal gear ring 1453 are integrally formed components. Optionally, the first internal gear ring 1443 and the second internal gear ring 1453 are the same component, that is, the transmission mechanism 14 includes an internal gear ring 146, and the internal gear ring 146 enables the first planet gear 1441 and the second planet gear 1451 to perform planetary motion respectively. The internal gear ring 146 not only meshes with the first planet gear 1441 to enable the first planet gear 1441 to perform planetary motion, but also meshes with the second planet gear 1451 to enable the second planet gear 1451 to perform planetary motion. In some alternative embodiments, the first internal gear ring 1443 and the second internal gear ring 1453 are two components, and there is no relative displacement between the first internal gear ring 1443 and the second internal gear ring 1453 to ensure that the transmission ratio is basically constant.

[0058] It should be noted that the motor 12, the transmission mechanism 14, and the impact mechanism 15 can share some structures. Therefore, the present disclosure does not intend to limit the above devices to completely independent parts.

[0059] As Figure 2 shown, along the direction of the first axis 101, the first bearing 1512 for supporting the main shaft 151 is closer to the output shaft 131 than the multi-stage planetary transmission group 140. The first bearing 1512 restricts the axial displacement of the internal gear ring 146. Optionally, the first bearing 1512 partially overlaps with the second planet carrier 1452 along the direction of the first axis 101. Optionally, the first bearing 1512 has no overlapping part with the elastic element 154 along the direction of the first axis 101. Optionally, the first bearing 1512 is arranged in the housing assembly 14a.

[0060] As Figure 6 shown, the motor 12 is a brushless DC (BLDC) motor. Optionally, for an internal rotor DC brushless motor, the nominal diameter R1 of the stator of the motor 12 is less than or equal to 50 mm. For example, the nominal diameter R1 of the stator of the motor 12 is 48 mm. The rotational speed range of the motor 12 is 13000 - 22000 RPM. As Figures 5 to 9 shown, a motor front bearing 124 for supporting the rotation of the drive shaft 121 is provided at the front end of the motor 12. The motor front bearing 124 is positioned in the housing assembly 14a. Among them, the diameter R2 of the motor front bearing 124 is less than or equal to 20 mm. For example, the diameter R2 of the motor front bearing 124 is 16 mm. A positioning protrusion 147 for restricting the axial displacement of the motor front bearing 124 is arranged in the housing assembly 14a, and the diameter R3 of the hole formed by the positioning protrusion 147 is less than or equal to 18 mm. For example, the diameter R3 of the hole formed by the positioning protrusion 147 is 14 mm.

[0061] As Figure 2and Figure 9 As shown, in this embodiment, the diameter R4 of the internal gear ring 146 is less than or equal to 50 mm. Optionally, the diameter R4 of the internal gear ring 146 is less than or equal to 48 mm. Optionally, the diameter R4 of the internal gear ring 146 is less than or equal to 44 mm. Optionally, the diameter R4 of the internal gear ring 146 is less than or equal to 42 mm. Optionally, the diameter R4 of the internal gear ring 146 is less than or equal to 40 mm. In this embodiment, the axial length of the internal gear ring 146 is set to L4, where L4 is the overall length of the internal gear ring. When the internal gear ring is a split structure of a first internal gear ring and a second internal gear ring, the length of L4 is the total length when the first internal gear ring and the second internal gear ring are installed in place. As Figure 9 shown, when the internal gear ring 146 is an integral structure, L4 is the axial length of the internal gear ring 146. In this embodiment, the ratio of the diameter R4 to the length L4 of the internal gear ring 146 is less than or equal to 8.5. In some embodiments, the ratio of the diameter R4 to the length L4 of the internal gear ring 146 is less than or equal to 8, 7.5, 7, 6.5, 6. To ensure that the transmission mechanism outputs a larger speed ratio while still ensuring a compact radial dimension and the compactness of the whole machine.

[0062] As Figure 6 shown, to enable the impact wrench 100 to output higher torque, it can be achieved by increasing the mass of the impact block 152 and / or increasing the rotational speed of the impact block 152, so as to provide increased kinetic energy during impact. In this embodiment, it is defined that the diameter R5 of the impact block 152 is greater than or equal to 40 mm. Optionally, the diameter R5 of the impact block 152 is 44 mm. Optionally, the mass of the impact block 152 is greater than or equal to 120 g. In some embodiments, the mass of the impact block 152 is greater than or equal to 125 g. The moment of inertia of the impact block 152 is greater than or equal to 35 kg·mm 2。The impact block 152 can meet the requirements of the output torque of the impact wrench 100 and ensure the compactness of the whole machine. Among them, in this embodiment, the diameter R4 of the internal gear ring 146 is smaller than the diameter R5 of the impact block 152. In this embodiment, the impact frequency is greater than or equal to 2500 IPM and less than or equal to 3900 IPM. As defined herein, "impact frequency" refers to the number of impacts applied by the impact block 152 on the anvil 153 per unit time, and IPM represents the number of impacts per minute (Impacts Per Minute). The maximum rotational speed of the output shaft 131 is less than or equal to 3000 RPM. In some embodiments, the maximum rotational speed of the output shaft 131 is less than or equal to 2500 RPM. In some embodiments, the no-load rotational speed of the output shaft 131 is less than or equal to 3000 RPM. In some embodiments, the no-load rotational speed of the output shaft 131 is less than or equal to 2500 RPM. Among them, the no-load rotational speed is during the operation of the impact tool in the no-load state. When the output shaft 131 is not used to apply torque to the workpiece, the common rotation of the main shaft 151, the impact block 152 and the anvil 153 defines the "output speed" of the impact tool, which is measured in revolutions per minute.

[0063] As Figures 7 to 9 shown, to ensure the radial compactness of the impact wrench 100, a first recess 148 is provided on the outside of the housing assembly 14a. As Figure 3 shown, the first recess 148 cooperates with the protrusion 1112 on the inner side of the motor housing 111 to limit the circumferential movement of the housing assembly 14a. A second recess 149 extending radially outward is provided on the inner side wall of the housing assembly 14a. The second recess 149 cooperates with the limiting protrusion 1461 of the internal gear ring 146 to limit the circumferential movement of the internal gear ring 146. To ensure the overall strength of the housing assembly 14a and the manufacturability of the mold, the second recess 149 and the first recess 148 are staggered to ensure uniform wall thickness of the housing assembly 14a. Optionally, a plurality of second recesses 149 are evenly arranged in the circumferential direction, and 6 are arranged within a circumference of 360°. A plurality of first recesses 148 are arranged in the circumferential direction. Optionally, 2 are arranged within a circumference of 360°. Optionally, the first recess 148 is arranged between two adjacent second recesses 149. Optionally. The first recess 148 and the second recess 149 partially overlap in the radial direction. To reduce the radial dimension of the transmission mechanism. Furthermore, the radial dimension of the whole machine is ensured.

[0064] As Figures 10 to 11As shown, for the battery pack 30, the nominal voltage of the battery pack 30 is less than 18V. In some embodiments, the nominal voltage of the battery pack 30 is greater than or equal to 3V and less than or equal to 9V. The nominal voltage generally refers to the voltage specified by the manufacturer or seller on the labels, packages, user manuals, specifications, advertisements, marketing, or other supporting documents of these products, so that users can understand which power tools and battery packs can operate with each other. Alternatively, the nominal voltage of the battery pack 30 can also be obtained by detection or calculation. The nominal voltage can be the voltage of the battery pack when the state of charge (SOC) of its battery is 50%. Optionally, the battery pack 30 includes a battery pack housing 31 and battery cells 32. The voltage of a single battery cell unit 323 is generally between 3.6V and 4.2V. In this embodiment, the battery pack 30 includes two to five battery cell units 323. The battery cell units 323 are connected in series, so the nominal voltage of the battery pack 100 can be considered to be 8V to 18V.

[0065] It can be understood that the nominal voltage of the battery pack 30 is related to the number of battery cell units 323 connected in series in the battery pack 30. For example, when the number of battery cell units 323 in the battery pack 30 is 1, the nominal voltage of the battery pack 30 can be considered to be 3.6V to 4.2V, specifically, it can be 3.6V, 4V, or 4.2V.

[0066] In some embodiments, the nominal voltage of the battery pack 30 is greater than or equal to 3V and less than 18V. Similarly, when the number of battery cell units 323 connected in series in the battery pack 30 is 3, the nominal voltage of the battery pack 30 can be considered to be 10.8V to 12.6V, specifically, it can be 10.8V, 12V, or 12.6V. Similarly, when the number of battery cell units 323 connected in series in the battery pack 30 is 4, the nominal voltage of the battery pack 30 can be considered to be 14.4V to 16.8V, specifically, it can be considered to be 14.4V, 16V, or 16.8V.

[0067] In this embodiment, the nominal voltage of the battery pack 30 is greater than or equal to 7V and less than or equal to 9V. For example, in this embodiment, the number of battery cell units 323 is 2, and the two battery cell units 323 are connected in series, then the nominal voltage of the battery pack 30 can be considered to be 7.2V to 8.4V, specifically, it can be 7.2V, 8V, or 8.4V.

[0068] In some other embodiments, the number of the battery cells 323 of the battery pack 30 is less than or equal to 4, and the 4 battery cells 323 can be connected in series with each other. Alternatively, the 4 battery cells 323 can also form two battery cell groups, and the two battery cell groups are connected in parallel with each other, and the two battery cells 323 in each battery cell group are connected in series with each other. When 4 battery cells form two battery cell groups, similarly, the nominal voltage of the battery pack 30 can be considered as 8V. In some embodiments, the nominal voltage of the battery pack 30 is less than or equal to 9V. In some embodiments, the nominal voltage of the battery pack 30 is greater than or equal to 7V.

[0069] In some embodiments, the nominal voltage of the battery pack 30 is less than or equal to 13V. For example, the battery pack 30 includes three battery cells 323 connected in series, and at this time, the nominal voltage of the battery pack 30 can be 10.8V, 12V or 12.6V.

[0070] The battery pack 30 can be a lithium battery pack, a solid-state battery pack or a soft-pack battery pack. The battery pack 30 includes a first part 33 and a second part 34. Among them, when the battery pack 30 is combined with the holding part 113, the first part 33 is at least partially disposed within the holding part 113, and the second part 34 is located outside the holding part 113. Optionally, the first part 33 includes a first group of battery cells, and the second part 34 includes a second group of battery cells. For the convenience of description, in this embodiment, the battery cells 323 in the first group of battery cells can also be defined as the first battery cells 323a, and the battery cells 323 in the second group of battery cells can be defined as the second battery cells 323b. Among them, both the first battery cells and the second battery cells are pouch-shaped battery cells. The first battery cells are partially or entirely located within the holding part 113, and the second battery cells are located outside the holding part 113. The extension plane of the first battery cells is parallel to the first straight plane. The extension plane of the second battery cells is perpendicular to the first straight line. The extension plane of the second battery cells is perpendicular to the extension plane of the first battery cells. The battery pack housing 31 is used to accommodate the first battery cells and the second battery cells. Among them, the battery pack housing is substantially in the shape of the letter "T", so that the volume of the battery pack 30 can be reduced while increasing the capacity of the battery pack 30. Alternatively, in some embodiments, the battery pack housing can also be substantially in the shape of the letter "L".

[0071] In this embodiment, as Figure 1As described above, the axial length L1 from the rear end of the housing 11 to the front end of the anvil 153 is less than or equal to 145 mm. In some embodiments, the axial length L1 from the rear end of the housing 11 to the front end of the anvil 153 is less than or equal to 140 mm. In some embodiments, the axial length L1 from the rear end of the housing 11 to the front end of the anvil 153 is less than or equal to 135 mm. In some embodiments, the axial length L1 from the rear end of the housing 11 to the front end of the anvil 153 is less than or equal to 125 mm. In this embodiment, since the output shaft 131 and the anvil 153 are integrally formed components and the output shaft 131 is provided at the front end of the anvil 153, it can be seen that the axial length L1 from the rear end of the housing 11 to the front end of the output shaft 131 is less than or equal to 145 mm. In some embodiments, the axial length L1 from the rear end of the housing 11 to the front end of the output shaft 131 is less than or equal to 140 mm. In some embodiments, the axial length L1 from the rear end of the housing 11 to the front end of the output shaft 131 is less than or equal to 135 mm. In some embodiments, the axial length L1 from the rear end of the housing 11 to the front end of the output shaft 131 is less than or equal to 125 mm. Using a battery pack with a low nominal voltage ensures the output torque while maintaining the overall axial length of the impact tool, without affecting the overall compactness of the tool, enabling the product to be conveniently applied to narrow working conditions.

[0072] As Figure 3 shown, the impact wrench 100 further includes a lighting assembly 17. The lighting assembly is configured to illuminate the working area of the impact wrench 100. Among them, the lighting assembly 17 is provided below the output housing 112 or on the lower side of the output housing 112.

[0073] In some embodiments, the lighting assembly is provided on the output housing. Optionally, the lighting assembly includes a plurality of light-emitting bodies arranged circumferentially along the output shaft 131 or arranged in a ring shape, and the light-emitting bodies include lamp beads or lamp boards. In some embodiments, the lighting assembly includes lamp beads and a reflector for providing a surface light source. Optionally, the reflector is in a ring shape. In some embodiments, the lighting assembly is controlled by a trigger switch. In some embodiments, an independent control operation part is provided to control the lighting assembly. In some embodiments, the working mode of the lighting assembly is adjustable. Among them, the working mode includes brightness, color temperature, delay-on time, delay-off time, constant-on or flashing, and other modes affecting the lighting effect.

[0074] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art of this industry should understand that the above embodiments do not limit the present application in any form. Any technical solutions obtained by using equivalent replacements or equivalent transformations fall within the protection scope of the present application.

Claims

1. An impact tool, comprising: A motor including a drive shaft rotating about a first axis; An output shaft including an output axis defined by itself, the output shaft rotating about the output axis to output power; An impact mechanism applying an impact force to the output shaft, the impact mechanism including an impact block driven by the motor and an anvil cooperating with the impact block and being impacted by the impact block; A transmission mechanism configured to transmit the torque output by the drive shaft to the output shaft, the transmission mechanism including a multi-stage transmission component; A DC power supply supplying power to at least the motor, the nominal voltage of the DC power supply being less than 18V; Wherein, the fastening torque of the output shaft on the workpiece is greater than or equal to 170 N·m.

2. The impact tool according to claim 1, characterized in that, The multi-stage transmission component includes at least two planetary gear reduction components.

3. The impact tool according to claim 1, characterized in that, The multi-stage transmission component includes: A first planet carrier disposed in front of the motor, A first planetary gear supported by the first planet carrier; A second planet carrier disposed in front of the first planet carrier; A second planetary gear supported by the second planet carrier; An internal gear ring for causing the second planetary gear to perform a planetary motion.

4. The impact tool according to claim 3, characterized in that, The impact mechanism further includes a main shaft connecting the impact block and the drive shaft and a first bearing supporting the rotation of the main shaft, the first bearing restricting the axial displacement of the internal gear ring.

5. The impact tool according to claim 4, characterized in that, The ratio of the rotational speed of the drive shaft to the rotational speed of the main shaft is substantially a constant value.

6. The impact tool according to claim 4, characterized in that, The speed ratio from the drive shaft to the main shaft is greater than or equal to 9:

1.

7. The impact tool according to claim 3, characterized in that, The internal gear ring causes the first planetary gear and the second planetary gear to perform planetary motions respectively.

8. The impact tool according to claim 1, characterized in that, The maximum rotational speed of the output shaft is less than or equal to 3000 rpm.

9. The impact tool according to claim 1, characterized in that, The nominal voltage of the DC power supply is greater than or equal to 3V and less than or equal to 9V.

10. An impact tool, comprising: A motor including a drive shaft rotating about a first axis; An output shaft including an output axis defined by itself, the output shaft rotating about the output axis to output power; An impact mechanism applying an impact force to the output shaft, the impact mechanism including an impact block driven by the motor and an anvil cooperating with the impact block and being impacted by the impact block; A transmission mechanism configured to transmit the torque output by the drive shaft to the output shaft; A DC power supply supplying power to at least the motor, the nominal voltage of the DC power supply being greater than or equal to 3V and less than or equal to 9V; Wherein, the fastening torque of the output shaft on the workpiece is greater than or equal to 170 N·m.

11. An impact tool, comprising: A motor including a drive shaft rotating about a first axis; An output shaft including an output axis defined by itself, the output shaft rotating about the output axis to output power; An impact mechanism applying an impact force to the output shaft, the impact mechanism including an impact block driven by the motor, an anvil cooperating with the impact block and being impacted by the impact block, and a main shaft connecting the impact block and the drive shaft A transmission mechanism configured to transmit the torque output by the drive shaft to the main shaft; the speed ratio from the drive shaft to the main shaft is greater than or equal to 9:1; A DC power supply supplying power to at least the motor, the nominal voltage of the DC power supply being greater than or equal to 3V and less than or equal to 9V; Among them, the tightening torque of the output shaft on the workpiece is greater than or equal to 170 N·m.

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