Working head clamping mechanism and power tools

Abstract

This invention discloses a working head clamping mechanism and a power tool. The clamping structure includes an output shaft, a collet, and a locking cap. A paired first axial clamping portion and a second axial clamping portion are provided between the output shaft and the collet. An axial elastic element is also provided between the output shaft and the collet, applying an axial separating force to the first and second axial clamping portions. A paired first circumferential clamping portion and a second circumferential clamping portion are provided between the collet and the locking cap. A circumferential elastic element is provided between the locking cap and the output shaft, applying a circumferential abutting force to the first and second circumferential clamping portions. Inserting the working head pushes against the axial elastic element; once in place, the circumferential elastic element allows the locking cap to automatically clamp the collet, thus achieving automatic locking of the collet. The operation of installing the working head is simple and convenient.

Description

Technical Field

[0001] This invention belongs to the field of power tool technology, specifically relating to a working head clamping mechanism and a power tool. Background Technology

[0002] Power tools, such as electric grinders, are used for grinding, polishing, carving, and other tasks. An electric grinder mainly consists of a main unit and a detachable workhead. The main unit includes a motor and a clamping mechanism for holding the workhead in place, which then drives the workhead to rotate.

[0003] Existing electric grinders primarily use a clamping structure consisting of a locking cap and a chuck. The locking cap is threaded onto the motor output shaft. To facilitate the installation and replacement of the working head, a spindle lock is required on the main unit to lock the motor output shaft and prevent it from rotating during tightening and loosening of the locking cap. However, adding a spindle lock button to the main unit not only increases structural complexity but also makes changing the working head cumbersome and carries the risk of the output shaft accidentally jamming, impacting the user experience.

[0004] Therefore, it is necessary to improve the existing technology to overcome the aforementioned defects. Summary of the Invention

[0005] Therefore, the present invention aims to solve the technical problems of complex operation and low safety of clamping mechanisms in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides a working head clamping mechanism, comprising:

[0007] The output shaft is connected to and driven by the motor.

[0008] A chuck, driven by the output shaft, is adapted to engage with a working head to clamp or release the working head.

[0009] A locking cap, which engages with the chuck to clamp or release the working head;

[0010] A first axial clamping part and a second axial clamping part are provided between the output shaft and the chuck. An axial elastic element is also provided between the output shaft and the chuck. The axial elastic element applies an axial separating force to the first axial clamping part and the second axial clamping part.

[0011] A first circumferential clamping part and a second circumferential clamping part are provided between the chuck and the locking cap. A circumferential elastic element is provided between the locking cap and the output shaft. The circumferential elastic element applies a circumferential resisting force to the first circumferential clamping part and the second circumferential clamping part.

[0012] In one embodiment, one of the chuck and the locking cap is provided with a protrusion, and the other of the chuck and the locking cap is provided with a guide rail. The guide rail includes a circumferential rail and an axial rail that are connected. The length of the circumferential rail is greater than or equal to the circumferential clamping stroke of the first circumferential clamping part and the second circumferential clamping part. The length of the axial rail is greater than or equal to the axial clamping stroke of the first axial clamping part and the second axial clamping part.

[0013] In one embodiment, the first circumferential clamping portion, the protrusion, and the first axial clamping portion are sequentially formed on the outer periphery of the chuck in the axial direction, the protrusion is located between the first axial clamping portion and the first circumferential clamping portion, and the first circumferential clamping portion is formed at the free end of the chuck away from the output shaft.

[0014] In one embodiment, the chuck includes at least two clamping flaps with a gap between adjacent clamping flaps, and the at least two clamping flaps surround to form a chuck hole adapted to insert the working head to clamp the working head;

[0015] The first circumferential clamping portion is provided on the circumferential outer surface of the free end of the clamping flap, and in the axial direction, the first axial clamping portion is adjacent to the closed end of the gap.

[0016] In one embodiment, the chuck includes a first conical segment, a cylindrical segment, and a second conical segment arranged sequentially, the cylindrical segment being located between the first conical segment and the second conical segment, the gap being formed between the first conical segment and the cylindrical segment, the protrusion being disposed on the cylindrical segment, the outer surface of the first conical segment forming the first circumferential clamping portion, and the outer surface of the second conical segment forming the first axial clamping portion.

[0017] In one embodiment, the guide rail is disposed on the inner sidewall of the locking cap, the axial rail is disposed parallel to the axis of the output shaft, and the circumferential rail is connected to the end of the axial rail near the output shaft and extends along the circumferential direction of the inner wall of the locking cap; or,

[0018] The guide rail is disposed on the outer periphery of the chuck, the axial rail is disposed parallel to the axis of the chuck, and the circumferential rail is connected to the end of the axial rail away from the output shaft and extends around the outer circumferential direction of the chuck.

[0019] In one embodiment, the circumferential track includes a retaining sidewall adapted to abut against the protrusion to limit the axial separation of the first axial clamping portion and the second axial clamping portion under the pushing action of the axial elastic member.

[0020] In one embodiment, the first circumferential clamping portion is constructed as a conical surface, and the second circumferential clamping portion is constructed as a helical surface with a gradually changing radial dimension.

[0021] In one embodiment, the circumferential elastic element includes a torsion spring, one end of which is fixedly connected to the output shaft and the other end of which is fixedly connected to the locking cap. The torsion spring is used to apply a torque relative to the output shaft to the locking cap. The second circumferential clamping part is adapted to circumferentially clamp the first circumferential clamping part during the rotation of the locking cap relative to the chuck.

[0022] In addition, the present invention also provides a power tool including the clamping mechanism provided in any of the above embodiments.

[0023] The technical solution provided by this invention has the following advantages:

[0024] The present invention provides a working head clamping mechanism and a power tool. The clamping structure includes an output shaft, a chuck, and a locking cap. A paired first axial clamping part and a second axial clamping part are provided between the output shaft and the chuck. An axial elastic element is also provided between the output shaft and the chuck, applying an axial separating force to the first and second axial clamping parts. A paired first circumferential clamping part and a second circumferential clamping part are provided between the chuck and the locking cap. A circumferential elastic element is provided between the locking cap and the output shaft, applying a circumferential abutting force to the first and second circumferential clamping parts. The axial elastic element causes the chuck to have an axial movement tendency to detach from the output shaft, while the circumferential elastic element causes the locking cap to have a rotational tendency to circumferentially clamp the chuck. When the working head is inserted, it pushes against the axial elastic element. After reaching the desired position, the circumferential elastic element causes the locking cap to automatically clamp the chuck, thereby achieving automatic locking of the chuck. When the locking cap is unlocked, the working head can automatically pop out. The operation of disassembling and installing the working head is simple and convenient. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a three-dimensional structural diagram of the power tool provided in an embodiment of the present invention;

[0027] Figure 2 for Figure 1 The diagram shows a three-dimensional representation of the working head and clamping mechanism of a power tool in a disassembled state.

[0028] Figure 3 for Figure 2 The diagram shows a cross-sectional view of the clamping mechanism of the power tool in a disassembled state, passing through the axis of rotation.

[0029] Figure 4 A cross-sectional structural schematic diagram of the clamping mechanism of an electric tool provided in an embodiment of the present invention in the clamping state of the clamping working head;

[0030] Figure 5 A cross-sectional structural schematic diagram of the clamping mechanism of an electric tool provided in an embodiment of the present invention in the relaxed state of releasing the working head;

[0031] Figure 6 This is a schematic diagram of a cross-section of the clamping mechanism provided in an embodiment of the present invention in a clamped state, passing through the circumferential clamping portion.

[0032] Figure 7 A simplified schematic diagram of the mating structure of the clamping head and locking cap of the clamping mechanism provided in an embodiment of the present invention;

[0033] Figure 8 This is a simplified schematic diagram of the mating structure of the clamping head and locking cap of a clamping mechanism provided in another embodiment of the present invention. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0035] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0036] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention. Example 1

[0037] Please see Figure 1 and Figure 2 As shown, this embodiment provides a working head clamping mechanism 20 (hereinafter referred to as the clamping mechanism) for clamping and positioning the working head 50. Please refer to... Figure 1 and Figure 2The clamping mechanism 20 includes an output shaft 21, a chuck 23, and a locking cap 25. This embodiment applies the clamping mechanism 20 to... Figure 1 The power tools shown are for illustrative purposes only and should not be construed as limiting the invention. Figure 1 and Figure 4 As shown, in this implementation scenario, the power tool includes a main body 10 and a motor 15 disposed within the main body 10. The motor 15 is connected to a power source for outputting rotational power.

[0038] The output shaft 21 is connected to and driven by the motor 15 of the power tool. Specifically, the output shaft 21 is coaxially and fixedly connected to the rotating shaft of the motor 15, and rotates synchronously with the rotating shaft of the motor 15. The chuck 23 is connected at one end to the output shaft 21, and the other end is adapted to cooperate with the working head 50 to clamp or release the working head 50. When the chuck 23 is mounted on the output shaft 21, it rotates synchronously with the output shaft 21, thereby causing the motor 15 to drive the output shaft 21 and the chuck 23 to rotate synchronously. The locking cap 25 is sleeved on the outside of the chuck 23 and is used to cooperate with the chuck 23 to clamp or release the working head 50. The locking cap 25 has a through-hole 250 for inserting and removing the working head 50.

[0039] Specifically, the chuck 23 includes a connecting rod 231 and a limiting part 233, and the output shaft 21 includes a mounting hole 210. A limiting groove that cooperates with the limiting part 233 is also formed on the side wall of the output shaft 21 forming the mounting hole 210. When the connecting rod 231 is inserted into the mounting hole 210, the limiting part 233 cooperates with the limiting groove to limit the rotation, thereby realizing the anti-rotation connection between the chuck 23 and the output shaft 21. The chuck 23 can rotate synchronously with the output shaft 21.

[0040] The locking cap 25 has a locked position and a released position. Correspondingly, the chuck 23 has a clamped state and a released state. When the locking cap 25 is in the locked position, the chuck 23 is in the clamped state of clamping the working head 50. When the locking cap 25 is in the released position, the chuck 23 is in the released state of releasing the working head 50. The locking cap 25 can rotate relative to the chuck 23 to switch between the released position and the locked position.

[0041] It should be noted that the movement from the loosened position to the locked position of the locking cap corresponds to one rotation of the locking cap. The starting point of the rotation corresponds to the loosened position, and the ending point of the rotation corresponds to the locked position.

[0042] Please combine Figure 3As shown, the chuck 23 is provided with a first axial clamping portion 2323, and the output shaft 21 is provided with a second axial clamping portion 212 that matches the first axial clamping portion 2323. An axial elastic member 26 is also provided between the output shaft 21 and the chuck 23. The axial elastic member 26 is disposed in the mounting hole 210. One end of the axial elastic member 26 abuts against the output shaft 21, and the other end abuts against the chuck 23, and is used to apply an outward pushing force against the chuck 23. That is, the axial elastic member 26 applies an axial separating force to the first axial clamping portion 2323 and the second axial clamping portion 212. The chuck 23 is also provided with a first circumferential clamping portion 2321, and the locking cap 25 is provided with a second circumferential clamping portion 251 that matches the first circumferential clamping portion 2321. The second circumferential clamping portion 251 is inserted into the first circumferential clamping portion 2321 to circumferentially hold the first circumferential clamping portion 2321. A circumferential elastic element 27 is provided between the locking cap 25 and the output shaft 21. One end of the circumferential elastic element 27 is connected to the output shaft 21, and the other end is connected to the locking cap 25. It is used to apply a torque to the locking cap 25 relative to the output shaft 21 in the circumferential direction, so as to apply a circumferential holding force to the first circumferential clamping part 2321 and the second circumferential clamping part 251.

[0043] It should be noted that the aforementioned "first and second axial clamping parts" refer to the axial direction of the elastic force of the axial elastic element that needs to be overcome during clamping. In other words, the "first axial clamping part" and the "second axial clamping part" need to axially compress the axial elastic element to overcome its elastic force in the clamping state. The "first and second circumferential clamping parts" refer to the circumferential direction of the force applied by the circumferential elastic element during the switching to the clamping state. In other words, the "first circumferential clamping part" and the "second circumferential clamping part" clamp in response to the circumferential torsional force of the circumferential elastic element.

[0044] In this embodiment, when the first axial clamping part 2323 and the second axial clamping part 212 cooperate with each other, the axial elastic member 26 is in a compressed state, so as to apply an axial pushing force away from the output shaft 21 to the chuck 23. The second circumferential clamping part 251 surrounds the first circumferential clamping part 2321 in the circumferential direction. Under the torque of the circumferential elastic member 27, the second circumferential clamping part 251 presses against the first circumferential clamping part 2321 in the circumferential direction, so that the chuck 23 is in a clamped state. In this embodiment, under the torque of the circumferential elastic member 27, the locking cap 25 can automatically rotate from the loose position to the locking position in response to the insertion of the working head 50, thereby realizing the automatic locking of the chuck 23. After the locking cap 25 leaves the locking position, the chuck 23 is ejected a distance away from the output shaft 21 under the action of the axial elastic member 26, which facilitates the removal of the working head, simplifies the operation steps of locking the chuck, and makes the installation and removal of the working head more convenient.

[0045] For specific details, please refer to... Figure 2 and Figure 3As shown, the chuck 23 has a protrusion 235, and the inner wall of the locking cap 25 is provided with a guide rail 253. The guide rail 253 includes a circumferential rail 2532 and an axial rail 2531 that are connected. The protrusion 235 is disposed in the guide rail 253 and can slide along the guide rail 253. The circumferential rail 2532 is connected to one end of the axial rail 2531 near the output shaft 21 and is connected to the axial rail 2531.

[0046] For ease of explanation, the end of the axial track 2531 furthest from the output shaft 21 is defined as the beginning end, and the opposite end is defined as the end end. The circumferential track 2532 connects to the end end of the axial track 2531 and extends circumferentially along the inner wall of the locking cap 25. In a specific embodiment, the beginning end of the axial track 2531 has an abutting end wall; that is, the beginning end of the axial track 2531 furthest from the output shaft 21 is closed when the chuck 23 is in the relaxed state (see...). Figure 5 As shown), protrusion 235 and axial track 2531 engage with the abutting end wall away from output shaft 21, with protrusion 235 held at the beginning of axial track 2531. Circumferential track 2532 includes abutting sidewall 25321, which is the sidewall of circumferential track 2532 away from output shaft 21. When chuck 23 is in the clamped state (see...), Figure 4 As shown, the protrusion 235 abuts against and limits the abutting sidewall 25321 of the circumferential track 2532, thereby preventing the first axial clamping part 2321 and the second axial clamping part 212 from axially separating under the pushing action of the axial elastic member 26, thus keeping the chuck 23 in a clamped state. That is to say, the axial elastic member tends to separate the chuck and the output shaft, and the first axial clamping part and the second axial clamping part separate, but the abutting of the protrusion against the abutting sidewall makes the chuck overcome the action of the axial elastic member and abut against the output shaft, thereby making the first axial clamping part abut against the second axial clamping part and further clamping the working head.

[0047] The following section explains the fit between the protrusion and the guide rail, using the installation process of the working head as an example. Please refer to [link / reference needed]. Figure 5 and Figure 7 When the chuck 23 is in the relaxed state, the protrusion 235 is located at Figure 7Position B, as shown, is where protrusion 235 is located at the beginning of axial track 2531. The first axial clamping part 2323 and the second axial clamping part 212 are axially separated, allowing the working head 50 to be inserted into and removed from the chuck 23. When it is necessary to clamp the working head 50, press the working head 50 inward along the axial direction. The chuck 23 responds to the insertion of the working head 50 and moves along axial track 2531 from the beginning of axial track 2531 toward the output shaft 21. During the movement, it overcomes the elastic force of the axial elastic element 26. When it moves to the end of axial track 2531, that is, near the other end of output shaft 21 (connecting to one end of circumferential track 2532), the axial clamping stroke of the chuck 23 is completed. At this point, the protrusion 235 is located at the connection between the circumferential track 2532 and the axial track 2531. Under the torque of the circumferential elastic element 27, the locking cap 25 rotates relative to the chuck 23. Correspondingly, the protrusion 235 slides from the end of the axial track 2531 into the circumferential track 2532, and finally the protrusion 235 is located relative to the circumferential track 2532. Figure 7 At position A, and axially limited and supported by the circumferential track 2532, the chuck 23 switches to the clamping state. In the clamping state, the protrusion 235 abuts against the supporting side wall 25321 of the circumferential track 2532, preventing the chuck 23 from axially moving away from the output shaft 21 under the action of the axial elastic element. The second axial clamping part 212 and the second circumferential clamping part 251 abut against each other, and the second circumferential clamping part 251 clamps the first circumferential clamping part 2321 of the chuck 23 circumferentially, thus clamping the working head 50. From the rotation of the locking cap 25 to its stop, this process achieves the clamping of the first circumferential clamping part 2321 and the second circumferential clamping part 251. The stroke through which the locking cap 25 rotates is the circumferential clamping stroke of the first circumferential clamping part 2321 and the second circumferential clamping part 251.

[0048] The length of the axial track 2531 is greater than or equal to the axial clamping stroke of the first axial clamping part 2323 and the second axial clamping part 212, and the length of the circumferential track 2532 is greater than or equal to the circumferential clamping stroke of the first circumferential clamping part 2321 and the second circumferential clamping part 251. This configuration provides sufficient stroke margin, ensuring that the clamping effect is not affected by insufficient stroke, and guaranteeing the reliability of the working head clamping.

[0049] When it is necessary to disassemble or replace the working head 50, rotate the locking cap 25 in the opposite direction. The protrusion 235 slides from the circumferential track 2532 to the end of the axial track 2531. Under the reset action of the axial elastic element 26, the protrusion 235 slides from the end of the axial track 2351 to the beginning of the axial track 2351. The protrusion 235 returns to position B, the chuck 23 switches to the relaxed state, and the working head 50 can be pulled out.

[0050] Please see Figure 3 and Figure 4The clamping mechanism 20 also includes a one-way bearing 28 for rotating the output shaft 21 in a single direction. The one-way bearing 28 is sleeved on the end of the output shaft 21 near the chuck 23 and is fixedly mounted on its outer periphery. On the one hand, the one-way bearing can support the output shaft and suppress vibration at the end of the output shaft. On the other hand, the one-way bearing can restrict the output shaft to rotate only in the direction of the motor's drive, and not in the opposite direction. Therefore, the output shaft will not rotate when the locking cap is rotated in the opposite direction, eliminating the need for a shaft lock to fix the output shaft. This simplifies the structure and makes disassembling the working head simple and convenient.

[0051] In one specific embodiment, please refer to the following: Figure 2 and Figure 3 The protrusion 235, the first circumferential clamping portion 2321, and the first axial clamping portion 2323 are all formed on the outer periphery of the chuck 23. The protrusion 235 is located axially between the first axial clamping portion 2323 and the first circumferential clamping portion 2321. The first axial clamping portion 2323 is formed at the end of the protrusion 235 near the output shaft 21, and the first circumferential clamping portion 2321 is formed at the end of the protrusion 235 away from the output shaft 21. During clamping, one side of the protrusion 235 abuts against and limits the end face of the output shaft 21, and the opposite side of the protrusion 235 abuts against and limits the locking cap 25. The protrusion is located between the first axial clamping portion and the first circumferential clamping portion, which serves to limit the movement and also increases the structural strength of the chuck, improving the reliability of clamping the working head.

[0052] For details, please refer to the following: Figure 2 and Figure 3 The chuck 23 includes two clamping flaps 232, located at the end of the connecting rod 231 away from the output shaft 21, and integrally formed with or fixedly connected to the connecting rod 231. A gap 234 exists between adjacent clamping flaps 232, and the two clamping flaps 232 surround a chuck hole 230, which is adapted to insert and hold the working head 50. In the clamped state, the two clamping flaps 232 move closer together, the gap 234 between the clamping flaps 232 decreases, and the diameter of the chuck hole 230 decreases, thereby tightly clamping the working head 50.

[0053] It should be noted that the length of the clamping flap 232 is limited by the length of the gap 234, and the length of the clamping flap 232 is equal to the length of the gap 234. Axially, the chuck 23 includes a first conical segment, a cylindrical segment, and a second conical segment arranged sequentially. The cylindrical segment is located between the first and second conical segments, and the first conical segment forms the free end of the chuck 23. The gap 234 is formed on the first conical segment and the cylindrical segment, and the axial length of the clamping flap 232 (gap 234) is equal to the sum of the axial lengths of the first conical segment and the cylindrical segment. A protrusion 235 is provided on the cylindrical segment. A first circumferential clamping portion 2321 is formed on the outer surface of the first conical segment, and a first axial clamping portion 2321 is formed on the outer surface of the second conical segment. Both the first axial clamping portion 2323 and the first circumferential clamping portion 2321 are conical surfaces. The second conical segment is frustum-shaped, and the first axial clamping portion 2321 is the side surface of the frustum. In other words, the first circumferential clamping portion 2321 is located at the free end of the clamping flap 232, that is, the first circumferential clamping portion 2321 is formed on the outer circumferential surface of the free end of the clamping flap 232. The first axial clamping portion 2323 is adjacent to the closed end of the gap 234, and the first axial clamping portion 2323 and the gap 234 do not overlap in the axial direction. The axial length of the first circumferential clamping portion 2321 is greater than the axial length of the first axial clamping portion 2323. Thus, the clamping force bearing surface of the first circumferential clamping portion is larger, which can withstand greater pressure, thereby ensuring the reliability of the working head clamping.

[0054] Of course, the number of clamping flaps can be more than two, such as three, four or five. Multiple clamping flaps are arranged around the axis of the chuck and can move inward together under the action of circumferential inward pressure to achieve clamping of the working head. There is no limitation here.

[0055] In specific implementation scenarios, please refer to the following: Figure 2 The working head 50 includes a working end 53, a connecting end 51, and limiting ribs 52. The connecting end 51 is straight, and the limiting ribs 52 are located on the outer surface of the connecting end 51. The limiting ribs 52 are straight strips parallel to the axis of the chuck 23. The number of limiting ribs 52 is the same as the number of gaps 234, and they are used to insert into the corresponding gaps 234 to prevent rotation with the chuck 23. The insertion hole 250 of the locking cap 25 has a mating groove that matches the limiting ribs 52. The distribution of the mating groove is the same as the distribution of the limiting ribs 52, and they have the same shape. That is, the shape of the insertion hole 250 matches the distribution shape of the limiting ribs 52 on the connecting rod 51, so that the working head can smoothly connect to the chuck 23 through the insertion hole 250. When the connecting end 51 is inserted into the clamping flaps 232 through the chuck hole 230, the limiting ribs 52 are located in the gaps 234 between the clamping flaps 232, and the working head 50 can rotate synchronously with the chuck 23.

[0056] In a specific embodiment, the first axial clamping part 2323 is constructed as a conical surface, and the second axial clamping part 212 of the output shaft 21 is constructed as a matching conical surface. The first axial clamping part 2323 is inserted into the conical surface of the second axial clamping part 212, and the two conical surfaces are in close contact with each other. The second axial clamping part 212 surrounds the circumference of the first axial clamping part 2323 and applies a holding pressure to the first axial clamping part 2323, so that the corresponding positions of the clamping petals 232 tend to move closer to each other.

[0057] Please combine 2 and Figure 6 As shown, the first circumferential clamping part 2321 is constructed as a conical surface, and the second circumferential clamping part 251 is formed on the inner wall of the locking cap 25 and is constructed as a spiral surface with a gradually changing radial dimension. Figure 6 The trend of radial dimension gradient of the second circumferential clamping portion 251 is shown. Along Figure 6 Viewed counterclockwise, the second circumferential clamping portion 251 has a gradually decreasing radial dimension. When the locking cap 25 rotates relative to the chuck 23 under the action of the circumferential elastic member 27, the second circumferential clamping portion 251 gradually presses inward against the first circumferential clamping portion 2321, clamping the working head. Under the pushing action of the axial elastic member, the chuck can be held in the clamped position. Specifically, the second circumferential clamping portion 251 includes two helical surfaces, which respectively abut against the two clamping petals 232. Each helical surface has the same engagement method with the clamping petal. During the rotation of the locking cap, the inner diameter of the contact position between the helical surface and the clamping petal 232 becomes smaller and smaller, thereby achieving inward pressing of the clamping petal 232 and clamping the working head 50.

[0058] In a specific embodiment, the circumferential elastic element 27 includes a torsion spring for applying a rotational torque relative to the output shaft 21 to the locking cap 25. One end of the torsion spring is fixedly connected to the output shaft 21, and the other end is fixedly connected to the locking cap 25. When the protrusion 235 is... Figure 7 As shown, position B moves to the end of axial track 2531. There is no restraining structure on the right side of protrusion 235. Under the torque of the torsion spring, the locking cap automatically rotates relative to protrusion 235, causing protrusion 235 to be positioned... Figure 7 Position A is shown, and the chuck 23 remains in position A, with the chuck in a clamped state. The circumferential elastic element automatically locks and holds the clamping mechanism in the locked state, requiring no manual operation; the locking operation is simple.

[0059] When the working head 50 needs to be installed, the connecting end 51 and the limiting rib 52 of the working head 50 are inserted into the insertion hole 250 of the locking cap 25. The limiting rib 52 is inserted into the gap 234 of the chuck 23. The working head 50 is pressed against the chuck 23, so that the chuck 23 continues to press down against the elastic force of the axial elastic member 26. The protrusion 235 slides in the axial track 2531 until it slides to the end of the axial track 2531. The first axial clamping part 2323 and the second axial clamping part 212 abut against each other. The protrusion 235 is located at one end of the circumferential track 2532. Under the torsion of the torsion spring, the locking cap 25 rotates relative to the chuck 23. The protrusion 235 slides from one end of the circumferential track 2532 to the other end of the circumferential track 2532. The locking cap 25 slides to the locking position and remains in the locking position. The chuck 23 clamps the working head 50.

[0060] When disassembling the working head, the locking cap 25 is rotated to overcome the spring force of the torsion spring. The protrusion 235 slides in the circumferential track 2532, sliding from the other end of the circumferential track 2532 to the first end. The second circumferential clamping part 251 gradually loosens the first circumferential clamping part 2321. When the protrusion 235 slides to the end of the axial track 2531, the chuck 23 is ejected a certain distance under the action of the axial elastic member 26. The first axial clamping part 2323 and the second axial clamping part 212 separate, and the chuck 23 releases the working head 50, which can then be removed.

[0061] The working head clamping mechanism provided by this invention includes a paired first axial clamping part and a second axial clamping part between the output shaft and the chuck. An axial elastic element is also provided between the output shaft and the chuck, exerting an axial separating force on the first and second axial clamping parts. A paired first circumferential clamping part and a second circumferential clamping part are provided between the chuck and the locking cap. A circumferential elastic element is provided between the locking cap and the output shaft, exerting a circumferential abutting force on the first and second circumferential clamping parts. The axial elastic element causes the chuck to have an axial movement tendency to detach from the output shaft, while the circumferential elastic element causes the locking cap to have a rotational tendency to circumferentially clamp the chuck. When the working head is inserted, it pushes against the axial elastic element; once in place, the circumferential elastic element causes the locking cap to automatically clamp the chuck, thereby achieving automatic locking of the chuck. The operation of installing the working head is simple and convenient. Example 2

[0062] This embodiment also provides another working head clamping mechanism. This working head clamping mechanism is basically the same as the clamping mechanism described in Embodiment 1 above, except that the locking cap and the chuck are connected in a specific way. The following focuses on describing the differences; the same structures and components are described in detail in Embodiment 1 and will not be repeated here.

[0063] In this embodiment, reference Figure 8As shown, a protrusion 255 is provided on the locking cap, and a guide rail 236 that mates with the protrusion is provided on the chuck. The guide rail 236 also includes an axial rail and a circumferential rail. The difference from the above embodiment is that the circumferential rail is connected to the end of the axial rail away from the output shaft 21, that is, the circumferential rail is connected to the beginning end of the axial rail. Specifically, the guide rail 236 is provided on the outer periphery of the chuck, and can be provided circumferentially for the clamping flap or circumferentially for the connecting rod. The inner wall of the locking cap protrudes inward to form the protrusion 255. In the relaxed state, the protrusion 255 is located at the end B position of the axial rail. When the working head is inserted, the chuck moves towards the output shaft, and the protrusion 255 slides from position B to the other end of the axial rail. Under the action of the circumferential elastic member 27, the locking cap rotates relative to the chuck, causing the protrusion 255 to slide into the circumferential rail and remain at position A. Example 3

[0064] This embodiment provides a power tool, including the clamping mechanism provided in any of the above embodiments. For descriptions of related power tools and clamping mechanisms, please refer to the above embodiment section, which will not be repeated here.

[0065] Please see Figure 1 and Figure 2 As shown, the power tool can be configured with at least one working head 50, and a matching working head can be selected and installed in the clamping mechanism according to the type of work to be performed. In one specific embodiment, the power tool is an electric grinder, used for grinding, polishing, engraving, and other tasks.

[0066] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. Based on the embodiments of the present invention, those skilled in the art can make other variations or modifications without creative effort, and all such variations or modifications should fall within the scope of protection of the present invention.

Claims

1. A working head clamping mechanism, characterized in that, include: The output shaft is connected to and driven by the motor. A chuck, driven by the output shaft, is adapted to engage with a working head to clamp or release the working head. A locking cap, which engages with the chuck to clamp or release the working head; A first axial clamping part and a second axial clamping part are provided between the output shaft and the chuck. An axial elastic element is also provided between the output shaft and the chuck. The axial elastic element applies an axial separating force to the first axial clamping part and the second axial clamping part. A first circumferential clamping part and a second circumferential clamping part are provided between the chuck and the locking cap. A circumferential elastic element is provided between the locking cap and the output shaft. The circumferential elastic element applies a circumferential resisting force to the first circumferential clamping part and the second circumferential clamping part. One of the chuck and the locking cap is provided with a protrusion, and the other of the chuck and the locking cap is provided with a guide rail. The guide rail includes a circumferential rail and an axial rail that are connected. The length of the circumferential rail is greater than or equal to the circumferential clamping stroke of the first circumferential clamping part and the second circumferential clamping part; the length of the axial rail is greater than or equal to the axial clamping stroke of the first axial clamping part and the second axial clamping part.

2. The working head clamping mechanism according to claim 1, characterized in that, The first circumferential clamping portion, the protrusion, and the first axial clamping portion are sequentially formed on the outer periphery of the chuck in the axial direction. The protrusion is located between the first axial clamping portion and the first circumferential clamping portion. The first circumferential clamping portion is formed at the free end of the chuck away from the output shaft.

3. The working head clamping mechanism according to claim 2, characterized in that, The chuck includes at least two clamping flaps with a gap between adjacent clamping flaps, and the at least two clamping flaps surround to form a chuck hole adapted to insert the working head to clamp the working head; The first circumferential clamping portion is formed on the circumferential outer surface of the free end of the clamping flap, and in the axial direction, the first axial clamping portion is adjacent to the closed end of the gap.

4. The working head clamping mechanism according to claim 3, characterized in that, The chuck includes a first conical segment, a cylindrical segment, and a second conical segment arranged sequentially. The cylindrical segment is located between the first conical segment and the second conical segment. The gap is formed between the first conical segment and the cylindrical segment. The protrusion is provided on the cylindrical segment. The outer surface of the first conical segment forms the first circumferential clamping portion, and the outer surface of the second conical segment forms the first axial clamping portion.

5. The working head clamping mechanism according to claim 1, characterized in that, The guide rail is disposed on the inner sidewall of the locking cap; the axial rail is disposed parallel to the axis of the output shaft; the circumferential rail is connected to the end of the axial rail near the output shaft and extends circumferentially along the inner wall of the locking cap; or, The guide rail is disposed on the outer periphery of the chuck, the axial rail is disposed parallel to the axis of the chuck, and the circumferential rail is connected to the end of the axial rail away from the output shaft and extends around the outer circumferential direction of the chuck.

6. The working head clamping mechanism according to claim 1, characterized in that, The circumferential track includes a retaining sidewall adapted to abut against the protrusion to limit the axial separation of the first axial clamping portion and the second axial clamping portion under the pushing action of the axial elastic member.

7. The working head clamping mechanism according to claim 1, characterized in that, The first circumferential clamping part is constructed as a conical surface, and the second circumferential clamping part is constructed as a spiral surface with gradually changing radial dimensions.

8. The working head clamping mechanism as described in claim 1 or 7, characterized in that, The circumferential elastic element includes a torsion spring, one end of which is fixedly connected to the output shaft and the other end of which is fixedly connected to the locking cap. The torsion spring is used to apply a torque relative to the output shaft to the locking cap. The second circumferential clamping part is adapted to circumferentially clamp the first circumferential clamping part during the rotation of the locking cap relative to the chuck.

9. A power tool, characterized in that, Includes the working head clamping mechanism as described in any one of claims 1-8.

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