A safety clutch structure and power tool

Abstract

This application discloses a safety clutch structure and a power tool. The safety clutch structure, used for the safe clutch engagement of a power tool, includes: a rotating sleeve for connecting a tool output head; a pressure sleeve slidably connected to the rotating sleeve; a clutch gear sleeved on the outer circumference of the rotating sleeve and fixed axially relative to the rotating sleeve; an elastic element connected between the pressure sleeve and the rotating sleeve for applying an axial force from the pressure sleeve toward the clutch gear; and a rolling element disposed between the pressure sleeve, the clutch gear, and the rotating sleeve, maintaining contact with all three under the force of the elastic element to achieve the clutch function. The safety clutch structure and power tool of this application achieve rapid and precise torque protection, while also having a compact structure and automatic reset after overload release.

Description

Technical Field

[0001] This application relates to the field of power tool technology, and more specifically, to a safety clutch structure and a power tool. Background Technology

[0002] In existing power tools, a separate safety clutch is often used to protect the motor and transmission system during output overload. This type of clutch is typically connected in series as a separate functional module in the drivetrain, resulting in a complex overall transmission structure, a large number of parts, and a significant increase in the tool's axial dimensions. For example, a common friction plate clutch requires a separate clutch housing, multiple sets of friction plates, and a clamping mechanism, which not only occupies a large space but also suffers from unstable torque settings after wear.

[0003] Another mechanism that uses a steel ball and an inclined plane to disengage the clutch, while simplified in structure, still requires additional clutch seats, cages, and other parts, making it complex and difficult to miniaturize and lighten the tool. Therefore, providing a safe clutch solution that highly integrates the clutch function into the transmission gear, thereby greatly simplifying the structure and saving axial installation space, has become a technical problem that needs to be solved in this field. Utility Model Content

[0004] In view of this, this application provides a safe clutch structure and power tool that integrates the clutch function directly into the transmission gear, eliminating the need for a separate clutch module. This significantly simplifies the transmission chain, reduces the number of parts, and substantially reduces the overall axial dimension of the structure. This allows the power tool to achieve a more compact and efficient design while providing reliable overload protection.

[0005] In a first aspect, this application provides a safety clutch structure, which includes: Rotating sleeve, used to connect the tool output head; The pressure sleeve is slidably connected to the rotating sleeve; A clutch gear is sleeved on the outer circumference of the rotating sleeve and fixed axially relative to the rotating sleeve. An elastic element, connected between the pressure sleeve and the rotating sleeve, is used to apply an axial force to the pressure sleeve in the direction of the clutch gear; A rolling element is disposed between the pressure sleeve, the clutch gear, and the rotating sleeve, and maintains contact with the three components under the force of the elastic element. The rotating sleeve and the rolling element are provided with a clutch structure. When the resistance torque of the tool output head on the rotating sleeve is lower than a set threshold, the clutch gear drives the rotating sleeve to rotate through the cooperation of the rolling element and the clutch structure. When the resistance torque reaches or exceeds the set threshold, the rolling element disengages from the clutch structure and moves radially under the drive of the clutch gear, pushing the pressure sleeve to overcome the force of the elastic element and slide axially away from the clutch gear, thereby interrupting the power transmission between the clutch gear and the rotating sleeve.

[0006] By adopting the above technical solution, the clutch gear, clutch structure, rolling elements, and reset elastic element are highly integrated into the axial direction of the rotating sleeve, realizing the integration of clutch function and power transmission function. This design fundamentally eliminates the traditional independent clutch module and its complex linkage mechanism, significantly shortens the transmission path, reduces the number of parts, and thus effectively compresses the axial space of the overall structure, providing key support for the miniaturization and lightweight design of power tools. At the same time, its purely mechanical triggering and reset mechanism responds quickly and requires no manual intervention, ensuring the reliability of overload protection and the continuity of operation.

[0007] In some embodiments, the clutch structure includes a plurality of recessed structures or curved profiles spaced apart circumferentially along the rotating sleeve, and the rolling element is embedded in the recessed structure or conforms to the curved profile under the action of the elastic element.

[0008] By adopting the above technical solution, the circumferentially distributed concave or curved contours provide a stable meshing position for the rolling elements, thereby working with the elastic elements to set a clear and definite clutch torque threshold. This cooperation method ensures smooth power transmission under normal conditions, while under overload, the rolling elements can reliably overcome constraints and disengage, triggering the clutch action, thus ensuring the accuracy of torque sensing and the consistency of action.

[0009] In some implementations, adjacent recessed structures or curved profiles are connected by a groove.

[0010] By adopting the above technical solution, the groove provides a smooth transition path for the rolling element to move circumferentially along the rotating sleeve after disengaging from a recessed structure. This not only guides the rolling element to accurately and smoothly enter the next engagement position, preparing for subsequent automatic reset, but also reduces the impact and wear during the movement of the rolling element, which helps to improve the service life and smoothness of the clutch structure.

[0011] In some embodiments, the end face of the pressure sleeve facing the clutch gear has a first inclined surface or groove, and the end face of the clutch gear facing the pressure sleeve has a corresponding second inclined surface or groove, and the rolling element is partially accommodated in the space formed by the first inclined surface or groove and the second inclined surface or groove.

[0012] By employing the above technical solution, the cooperating inclined surfaces or grooves constitute a highly efficient force conversion mechanism. When overload triggers and the rolling element generates radial displacement, the inclined surfaces or grooves can efficiently convert the radial motion of the rolling element into a thrust that drives the axial sliding of the pressure sleeve, thereby forcing the pressure sleeve to compress the elastic element and achieve rapid separation. This design decouples complex multidimensional motion, making the clutch action more direct and reliable.

[0013] In some embodiments, the clutch structure includes a plurality of recessed structures spaced apart circumferentially along the rotating sleeve, with a sliding groove connecting adjacent recessed structures. The clutch gear has a groove on its end face facing the pressure sleeve. When the resistance torque reaches or exceeds the set threshold, the rolling element is driven by the groove of the clutch gear to disengage from the recessed structure and enter the next adjacent recessed structure along the sliding groove.

[0014] By adopting the above technical solution, the specific action path under overload is clearly defined. The driving action of the clutch gear groove ensures that the rolling element can be actively and reliably squeezed out of the current groove. After disengagement, the slide guides its movement, causing it to quickly fall into the next groove under the drive of the gear rotation. This process is completed in a very short time, realizing instantaneous power cut-off and rapid re-engagement preparation, which is the key mechanical logic for realizing the "slippage-reset" cycle.

[0015] In some embodiments, the angle between the first or second inclined plane and the axis of rotation of the rotating sleeve ranges from 27° to 47°.

[0016] By adopting the above technical solution and optimizing the inclined plane angle within this range, an optimal balance can be achieved between separation force, reset force, structural compactness, and operational stability. A smaller angle is beneficial for generating a larger axial force to push the pressure sleeve under overload, ensuring reliable separation; while a larger angle helps reduce the torque required for reset and makes the meshing of the rolling elements in the recess more stable. This preferred range has been verified through extensive experiments and is a key design parameter for ensuring optimal clutch performance.

[0017] In some implementations, the elastic element is a compression spring, a disc spring, or a wave spring.

[0018] By adopting the above technical solutions, a variety of elastic elements are available, allowing designers to flexibly select the appropriate type based on different space constraints, force requirements, and cost considerations. Compression springs can provide a larger stroke and linear force, while disc springs or wave springs are more suitable for applications with extremely tight axial space. This enhances the adaptability and versatility of this clutch structure to different product platforms and torque setting ranges.

[0019] In some implementations, the rolling element is a ball, roller, or tapered roller.

[0020] By adopting the above technical solutions, rolling elements of different shapes can adapt to different load-bearing and motion requirements. Ball bearings have low friction and flexible movement; rollers have a large contact area and stronger load-bearing capacity; and tapered rollers can better withstand complex loads. These multiple options allow the clutch structure to be optimized for different operating conditions such as high speed, high torque, or the presence of axial force, improving design flexibility and reliability.

[0021] Secondly, this application provides an electric tool including the safety clutch structure of the first aspect.

[0022] By adopting the above technical solution and applying the highly integrated safety clutch structure to power tools, traditional complex clutch modules can be directly replaced. This effectively simplifies the internal transmission layout of the tool, freeing up valuable internal space to accommodate a more powerful motor or battery, or directly reducing the overall size of the tool, significantly improving the product's market competitiveness, ease of operation, and user experience.

[0023] In some embodiments, a drive gear that meshes with the clutch gear is also included, the axis of the drive gear being set at an angle to the axis of the rotating sleeve.

[0024] By adopting the above technical solution, it is clear that the clutch structure can be applied to scenarios that require changing the direction of power transmission, such as angular tools using bevel gear transmission (e.g., electric wrenches, angle grinders). This shows that the integrated clutch solution of the present invention can not only be used in direct transmission structures, but also seamlessly adapt to complex spatial transmission layouts, further demonstrating its design versatility and strong space-saving capabilities, which is particularly beneficial for achieving the compactness of multi-axis power tools.

[0025] In summary, this application has at least one of the following beneficial technical effects: 1. High integration and compact structure: By innovatively integrating the clutch function module (clutch structure, rolling elements, elastic elements) with the transmission gear (clutch gear) and axially arranging it on the rotating sleeve, the traditional independent and serial clutch components are completely eliminated, greatly simplifying the transmission chain, significantly reducing the number of parts and axial space occupation, and providing a core technical solution for the miniaturization and lightweighting of power tools.

[0026] 2. Rapid response and reliable protection: Utilizing a purely mechanical structure to achieve torque sensing and action execution. In case of overload, the power transmission can be cut off within milliseconds through the direct mechanical action of the rolling elements, inclined plane, and clutch structure. The response speed is fast, with no electronic delay, protecting the motor and transmission system from damage, while also preventing tool backlash from injuring the operator, ensuring high safety.

[0027] 3. Automatic Reset, Continuous Operation: After the overload is eliminated, the entire clutch structure can automatically and quickly return to the power engagement state thanks to the preload of the elastic element, without manual intervention or replacement of parts. This feature ensures the continuity of operation, greatly improves work efficiency and user experience, and is especially suitable for working conditions that require frequent starts and stops or may encounter intermittent jamming.

[0028] 4. Flexible design and strong versatility: Key components (such as elastic elements, rolling elements, and inclined plane angles) offer a variety of optional implementation methods and optimized parameters, enabling this structure to flexibly adapt to power tool product platforms with different torque levels, spatial dimensions, and transmission forms (straight shaft or with angle), and has wide applicability and good engineering scalability. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the external structure of the safety clutch structure of this application; Figure 2 This is a cross-sectional schematic diagram of the safety clutch structure of this application; Figure 3 yes Figure 2 Enlarged diagram of area A in the middle; Figure 4 This is an exploded structural diagram of the safety clutch structure of this application; Figure 5 This is a schematic diagram of the exploded cross-section of the safety clutch structure; Figure 6 This is a schematic cross-sectional view of the clutch gear and rolling elements of the safety clutch structure after disassembly. Figure 7 This is a schematic diagram of the clutch gear structure; Figure 8 yes Figure 7 Enlarged diagram of area C; Figure 9 This is a partial structural diagram of the power tool of this application.

[0030] Explanation of reference numerals in the attached drawings: 1. Rotating sleeve; 11. Retaining ring; 12. Recessed structure; 13. Slide groove; 2. Clutch gear; 21. Second inclined surface; 22. Groove; 23. End face tooth; 3. Pressure sleeve; 31. First inclined surface; 4. Front cylinder; 5. Elastic element; 6. Tool head; 7. Rolling element; 8. Machine body; 9. Drive assembly; 91. Helical gear; 92. Bevel gear. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the utility model will be further described in detail below with reference to the accompanying drawings. The components of the embodiments of this utility model described and shown in the accompanying drawings can be arranged and designed in various different configurations. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0034] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0035] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments can be combined with each other.

[0036] Example 1: A safety clutch structure This application provides a safe clutch structure designed to address the problems of large space occupation and lengthy transmission chains in traditional power tools with independent clutches. The following detailed description of specific embodiments will enable those skilled in the art to fully understand and implement this solution.

[0037] Please see Figures 1 to 7 This embodiment provides a safe clutch structure, the core concept of which is to integrate the clutch actuator with the transmission gear, thereby achieving a great reduction in axial dimension.

[0038] The safety clutch structure mainly includes a rotating sleeve 1, a pressure sleeve 3, a clutch gear 2, an elastic element 5, a rolling element 7, and an externally covered front cylinder 4, all arranged coaxially.

[0039] The rotating sleeve 1 serves as the power output shaft, with a connection interface (such as an internal hexagonal hole, spline, or thread) at one end for directly mounting and driving tool output heads (such as drill bits, screwdriver bits, or sockets). The rotating sleeve 1 is supported within the front cylinder 4 by bearings, ensuring smooth rotation.

[0040] The pressure sleeve 3 is fitted onto the rotating sleeve 1. The end face of the pressure sleeve 3 facing the clutch gear 2 has a first inclined surface 31, and the end face of the clutch gear 2 facing the pressure sleeve 3 has a corresponding groove 22. The rolling element 7 is partially accommodated in the space formed by the inclined surface and the groove 22.

[0041] The clutch gear 2 is a key component for the integration of this structure. It is essentially a gear whose external teeth mesh with a power source (typically a gear on a motor shaft) to input torque. The clutch gear 2 also fits around the outer circumference of the rotating sleeve 1, but it is axially fixed. This can be achieved by providing a shoulder, a retaining ring groove, and installing a retaining ring 11 on the rotating sleeve 1, or by axially positioning the side of the clutch gear 2 against a boss on the inner wall of the gearbox. Importantly, the inner bore of the clutch gear 2 and the outer circle of the rotating sleeve 1 are either clearance-fitted or connected via bearings, allowing relative rotation between them.

[0042] The elastic element 5 is installed between the pressure sleeve 3 and the rotating sleeve 1 at a fixed point (such as a shoulder or a retaining ring 11). In this embodiment, the elastic element 5 is a helical compression spring, which is pre-compressed to continuously apply an axial thrust (i.e., biasing force) towards the clutch gear 2 to the pressure sleeve 3. This force is the basis for setting the clutch trigger torque threshold. Depending on different space and force requirements, the elastic element 5 can also be replaced with a disc spring or a wave spring. Disc springs can provide a large elastic force in a very small axial space, while wave springs can provide a more uniform clamping force.

[0043] The rolling element 7 is the direct medium for power transmission and interruption. It typically consists of multiple high-hardness steel balls (rollers) evenly distributed circumferentially. These rolling elements 7 are housed within a space enclosed by the end face of the pressure sleeve 3, the end face of the clutch gear 2, and the outer circular surface of the rotating sleeve 1. Under the preload of the elastic element 5, the rolling element 7 maintains contact with these three parts simultaneously.

[0044] Please see Figure 7The clutch gear 2 has a groove 22 at one end and an end face tooth 23 at the other end for meshing with the power gear to transmit power. A second inclined surface is also provided between the groove 22 and the end face tooth 23.

[0045] The innovation of this structure lies in the special cooperation relationship and interaction logic between the aforementioned components, which is specifically achieved through the following design: First, a special contour constituting the clutch structure is machined on the outer circumferential surface of the rotating sleeve 1. (See reference...) Figure 4 A preferred form of this profile is a plurality of circumferentially distributed recessed structures 12 (such as arc-shaped recesses or V-shaped grooves), with adjacent recesses connected by gentle grooves 13. Under the action of elastic force, a portion of the sphere of the rolling element 7 is embedded (or "locked in") into these recessed structures 12. An alternative embodiment is a continuous curved profile (such as a sine wave profile), with the rolling element 7 conforming to the troughs of the profile. Both the recesses and troughs serve to provide a stable circumferential engagement point for the rolling element 7 during normal operation to transmit torque.

[0046] Secondly, a first guide surface surrounding the axis is machined on the end face of the pressure sleeve 3 facing the clutch gear 2. Similarly, a corresponding second guide surface is machined on the end face of the clutch gear 2 facing the pressure sleeve 3. These two guide surfaces together form a space to accommodate and guide the rolling element 7 after it disengages from the recessed structure 12. In a preferred embodiment, the guide surfaces are designed as inclined surfaces. That is, the first inclined surface 31 on the end face of the pressure sleeve 3 and the second inclined surface 21 on the end face of the clutch gear 2 are arranged opposite to each other to form a V-shaped or wedge-shaped groove. After the rolling element 7 disengages from the groove 22, it can enter the next groove 22 under the guidance of the first inclined surface 31 and the second inclined surface 21. The inclined surface design can efficiently convert the radial movement of the rolling element 7 into the axial movement of the pressure sleeve 3. The angle between the first inclined surface 31 or the second inclined surface 21 and the axis of the rotating sleeve 1 is optimized to be in the range of 27° to 47°. Too small an angle may result in excessive separation force or difficulty in resetting; too large an angle may result in unstable meshing and easy false triggering. A preferred angle after comprehensive balance is about 37°.

[0047] Based on the above figures, the working principle of this structure is as follows: Normal torque transmission state: When the motor drives the clutch gear 2 to rotate and the tool head 6 is under normal load (resistance torque is lower than the set threshold), the clutch gear 2 pushes the rolling element 7 through its groove 22. Since the rolling element 7 is tightly pressed into the recessed structure 12 of the rotating sleeve 1 by elastic force, this thrust drives the rotating sleeve 1 to rotate synchronously through the meshing action of the rolling element 7 and the side wall of the recessed structure 12, thereby driving the tool head 6 to work. At this time, the entire mechanism rotates as a rigid whole.

[0048] Overload protection trigger state: When the tool head 6 encounters excessive resistance (such as screws being tightened to the limit or the drill bit jamming), causing the resistance torque on the rotating sleeve 1 to reach or exceed a threshold determined by the elastic force, friction coefficient, and structural dimensions, the rotating sleeve 1 tends to stop, while the clutch gear 2 continues to rotate. This causes a sharp increase in the reaction force exerted by the sidewall of the recessed structure 12 of the rotating sleeve 1 on the rolling element 7. When this torque exceeds the threshold, the rolling element 7 is forcibly "squeezed out" from the current recessed structure 12. At the moment of extrusion, the second inclined surface 21 of the still rotating clutch gear 2 applies a force to the rolling element 7, forcing it to produce a radially outward displacement. This radial movement of the rolling element 7 compresses the first inclined surface 31 of the pressure sleeve 3 in contact with it, generating a huge axial separation force according to the inclined surface principle. This separation force overcomes the preload force of the elastic element 5, pushing the pressure sleeve 3 to slide away from the clutch gear 2. The pressure sleeve 3 moves backward, causing the rolling element 7 to completely disengage from the recessed structure 12 of the rotating sleeve 1. Once disengaged, the rolling element 7, driven by the second inclined surface 21 of the clutch gear 2 and the first inclined surface 31 of the pressure sleeve 3, rolls along the groove 13 on the surface of the rotating sleeve 1, quickly passing over the protrusion and falling into the next adjacent recessed structure 12. In the extremely short time between the rolling element 7 being squeezed out of the recessed structure 12 and falling into the next recessed structure, the torque transmission path between the clutch gear 2 and the rotating sleeve 1 is cut off. The clutch gear 2 begins to idle (slip) relative to the rotating sleeve 1, producing a "click" sound, and the tool head 6 stops rotating, thus protecting the motor and transmission system.

[0049] Automatic reset process: When the overload is released (e.g., the user releases the switch or the jamming disappears), the resistance torque acting on the rotating sleeve 1 decreases. The previously compressed elastic element 5 releases its elastic energy, pushing the pressure sleeve 3 back to its original position. The pressure sleeve 3 moves forward, forcing the rolling element 7 to slide back along the guide surface and be pressed back into the current recessed structure 12 of the rotating sleeve 1, restoring a stable engagement state. Power transmission is automatically re-established, and the tool can continue to work. This process requires no manual intervention, achieving automatic cyclic protection.

[0050] Furthermore, the rolling element 7 is not limited to balls; depending on the magnitude of the transmitted torque, cylindrical rollers or tapered rollers can also be used. Rollers provide a larger line contact area and have a stronger load-bearing capacity; tapered rollers are better able to adapt to inclined surfaces and axial forces.

[0051] Example 2: An electric tool including a safety clutch structure Please see Figure 8 and Figure 9 This embodiment applies the safety clutch structure described in Embodiment 1 to a power tool to demonstrate its integration method and advantages in a real product.

[0052] In this embodiment of the power tool, the front cylinder 4 and the body 8 are fixedly connected. A drive motor, a gearbox, and the aforementioned safety clutch structure are housed within the front cylinder 4 and the body 8. A drive assembly 9, which is connected to the motor, includes a helical gear 91 and a bevel gear 92. The helical gear 91 receives the output power from the motor and drives the bevel gear 92 to rotate. The clutch gear 2 meshes with the bevel gear 92, thereby transmitting the motor power to the clutch structure.

[0053] This safety clutch structure, as a compact integrated module, is directly installed within the body 8. Traditional designs typically require a separate clutch assembly connected in series after a multi-stage reduction gear, resulting in a long transmission chain, numerous parts, and large axial dimensions. In this design, since the clutch gear 2 itself integrates the clutch function, it can directly replace a driven gear in a traditional transmission chain. This eliminates a large number of components such as a separate clutch housing, shift fork, and pressure plate, significantly shortening the overall axial length of the gearbox and making the power tool's overall structure more compact and lightweight.

[0054] Specifically, the axis of the helical gear 91 of the drive assembly 9 is set at an angle to the axis of the rotating sleeve 1 (output shaft). This reveals the excellent adaptability and versatility of this structure. In a typical embodiment, both the drive gear and the clutch gear 2 are bevel gears 92, and their axes intersect perpendicularly in space. This allows this safety clutch structure to be perfectly applied to angular power tools that require a change in power direction, such as impact wrenches, angular grinders, and right-angle screwdrivers.

[0055] In this type of angular tool, the motor's output shaft is typically parallel to the handle direction, while the tool output head (such as a square head) needs to be perpendicular to the handle direction. Referring to the figures above, the workflow of this structure is as follows: The motor drives the bevel gear 92 to rotate via the drive assembly 9 → The bevel gear 92 drives the clutch gear 2, which is the driven bevel gear 92, to rotate (this completes a 90-degree power conversion) → Under normal load, the clutch gear 2 drives the rotating sleeve 1 to rotate through the meshing of the rolling element 7 and the recessed structure 12 of the rotating sleeve 1 → The rotating sleeve 1 directly drives the tool head 6 at the front end to work. When an overload occurs, its protection mechanism is exactly the same as in Embodiment 1, reliably and quickly cutting off power in angular transmission scenarios.

[0056] In summary, the safety clutch structure of this application, through ingenious mechanical integration design, achieves significant simplification and space saving of the transmission system while ensuring reliable overload protection and automatic reset functions. Its structure is simple and compact, with few parts, easy to assemble, and can flexibly adapt to various power tool configurations such as direct shaft transmission and angular transmission, exhibiting good versatility and economic benefits.

[0057] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments; the embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes, modifications, substitutions, and variations can be made to this utility model without departing from its spirit and scope, and all such changes, modifications, substitutions, and variations fall within the scope of the claimed utility model.

Claims

1. A safety clutch structure for use in power tools, characterized in that, include: Rotating sleeve, used to connect the tool output head; The pressure sleeve is slidably connected to the rotating sleeve; A clutch gear is sleeved on the outer circumference of the rotating sleeve and fixed axially relative to the rotating sleeve. An elastic element, connected between the pressure sleeve and the rotating sleeve, is used to apply an axial force to the pressure sleeve in the direction of the clutch gear; A rolling element is disposed between the pressure sleeve, the clutch gear, and the rotating sleeve, and maintains contact with the three components under the force of the elastic element. The rotating sleeve and the rolling element are provided with a clutch structure. When the resistance torque of the tool output head on the rotating sleeve is lower than a set threshold, the clutch gear drives the rotating sleeve to rotate through the cooperation of the rolling element and the clutch structure. When the resistance torque reaches or exceeds the set threshold, the rolling element disengages from the clutch structure and moves radially under the drive of the clutch gear, pushing the pressure sleeve to overcome the force of the elastic element and slide axially away from the clutch gear, thereby interrupting the power transmission between the clutch gear and the rotating sleeve.

2. The safety clutch structure according to claim 1, characterized in that, The clutch structure includes a plurality of recessed structures or curved contours distributed circumferentially along the rotating sleeve, and the rolling element is embedded in the recessed structure or conforms to the curved contour under the action of the elastic element.

3. The safety clutch structure according to claim 2, characterized in that, Adjacent recessed structures or curved profiles are connected by grooves.

4. The safety clutch structure according to claim 1, characterized in that, The end face of the pressure sleeve facing the clutch gear is provided with a first inclined surface or groove, and the end face of the clutch gear facing the pressure sleeve is provided with a corresponding second inclined surface or groove. The rolling element is partially accommodated in the space formed by the first inclined surface or groove and the second inclined surface or groove.

5. The safety clutch structure according to claim 4, characterized in that, The clutch structure includes a plurality of recessed structures spaced apart along the circumference of the rotating sleeve. A sliding groove is connected between adjacent recessed structures. The clutch gear has a groove on its end face facing the pressure sleeve. When the resistance torque reaches or exceeds the set threshold, the rolling element is driven by the groove of the clutch gear to disengage from the recessed structure and enter the next adjacent recessed structure along the sliding groove.

6. The safety clutch structure according to claim 4, characterized in that, The angle between the first or second inclined plane and the axis of rotation of the rotating sleeve ranges from 27° to 47°.

7. The safety clutch structure according to claim 1, characterized in that, The elastic element is a compression spring, disc spring, or wave spring.

8. The safety clutch structure according to claim 1, characterized in that, The rolling element is a ball, roller, or tapered roller.

9. A power tool, characterized in that, Includes the safety clutch structure as described in any one of claims 1-8.

10. The power tool according to claim 9, characterized in that, It also includes a drive gear that meshes with the clutch gear, the axis of the drive gear being set at an angle to the axis of the rotating sleeve.

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