Electric tool

Abstract

The utility model relates to an electric tool which comprises a shell, a motor, an output shaft and a shaft lock mechanism. The shaft lock mechanism comprises a lock ring arranged around the output shaft, and a cavity is formed between the lock ring and the output shaft; the shaft lock frame comprises a boss, and the boss is in linkage with the output shaft; a lock pin; the output shaft comprises a first locking surface, an unlocking surface and a second locking surface, and both the first locking surface and the second locking surface are cambered surfaces; when the motor drives the shaft lock frame to rotate, the lock pin is movably located between the unlocking face and the inner wall of the lock ring, and the shaft lock frame can drive the output shaft to rotate. When the output shaft is subjected to counter-acting force of the tool head to generate abnormal reverse rotation, the first locking face or the second locking face and the inner wall of the lock ring oppositely clamp the lock pin, and the lock pin locks the output shaft. According to the electric tool, by improving the shape of the outer wall of the output shaft, stress concentration at the contact position of the lock pin and the output shaft is effectively reduced or eliminated, abrasion of the output shaft is avoided, reliability of the shaft lock is improved, and the output shaft can bear larger torque.

Description

Technical Field

[0001] The utility model relates to the technical field of power tools, and particularly relates to a power tool. Background Art

[0002] Power tools generally are provided with an axial locking mechanism. The axial locking mechanism mainly includes an axial locking frame, a locking ring and a locking pin. The output shaft is locked through the cooperation of the locking pin and the locking ring. Specifically, when the motor normally drives the axial locking frame to rotate, the boss on the axial locking frame first pushes the locking pin to the unlocking position, and then pushes the output shaft to rotate. The locking pin located at the unlocking position can move and will not get stuck. When the reverse torque transmitted by the tool head to the output shaft exceeds the torque transmitted by the axial locking frame to the output shaft, the locking pin gets stuck between the output shaft and the boss of the axial locking frame, and neither the axial locking frame nor the output shaft can rotate in the reverse direction, realizing the axial locking function.

[0003] For existing axial locking mechanisms, such as the contraction mechanism adopted in Patent CN115229738A, when the locking column is in the locking position, the locking column can contact both the inner wall surface and the first surface at the same time. The position of the locking column in the circumferential direction around the first axis is blocked, and the rotation of the output shaft relative to the housing is locked. In this solution, the locking column in the locking position is in line contact with the output shaft, and there is serious stress concentration at the contact position between the two, which easily causes wear of the output shaft, and then causes the locking column to slip and the axial locking function to fail. Summary of the Utility Model

[0004] Based on the above defects in the prior art, the purpose of the present utility model is to provide a power tool. By improving the outer wall shape of the output shaft, the stress concentration at the contact position between the locking pin and the output shaft can be effectively reduced or eliminated, avoiding wear of the output shaft and causing the axial locking mechanism to slip, improving the reliability of axial locking, and enabling the output shaft to withstand a greater torque.

[0005] To this end, the present utility model provides the following technical solutions.

[0006] The present utility model provides a power tool, which includes a housing, a motor, an output shaft for driving a tool head to operate, and an axial locking mechanism; the axial locking mechanism includes:

[0007] A locking ring, which is installed on the housing, the locking ring is arranged around the output shaft and a chamber is formed between the two;

[0008] An axial locking frame, which is driven by the motor and includes a boss, the boss extends into the chamber and is linked with the output shaft;

[0009] A locking pin, which is located in the chamber;

[0010] Wherein, the outer wall of one side of the output shaft facing the locking pin includes a first locking surface, an unlocking surface, and a second locking surface arranged in sequence, and both the first locking surface and the second locking surface are arc surfaces;

[0011] When the motor drives the shaft lock frame to rotate, the locking pin is movably located between the unlocking surface and the inner wall of the locking ring, and the shaft lock frame can drive the output shaft to rotate;

[0012] When the output shaft generates abnormal reverse rotation due to the reaction force of the tool head, the first locking surface or the second locking surface and the inner wall of the locking ring clamp the locking pin in opposite directions, so that the locking pin locks the output shaft; wherein, if the locking pin abuts against the first locking surface, the two are in surface-to-surface contact, and if the locking pin abuts against the second locking surface, the two are in surface-to-surface contact.

[0013] Optionally, the outer wall of the output shaft includes a convex portion and a concave portion arranged in sequence along the circumference, and the first locking surface, the unlocking surface, and the second locking surface are arranged on the outer wall of the convex portion.

[0014] Optionally, the boss is provided with a convex structure extending axially, and the convex structure extends into the concave portion so that the boss is linked with the output shaft.

[0015] Optionally, the number of the convex portions is three, and they are evenly spaced apart along the circumference, and the concave portion is formed between two adjacent convex portions, and the convex structure and the concave portion are arranged in one-to-one matching.

[0016] Optionally, there are gaps between the circumferential two side walls of the convex structure and the concave portion.

[0017] Optionally, the first locking surface and the second locking surface are symmetrically arranged about the axis of the output shaft.

[0018] Optionally, the ratio of the width of the first locking surface to the width of the unlocking surface is 1:1.5 - 1:3.

[0019] Optionally, the connection between the first locking surface and the unlocking surface is an arc surface, and the connection between the unlocking surface and the second locking surface is an arc surface.

[0020] Optionally, a first bearing and a second bearing are sleeved on the outer circumference of the output shaft.

[0021] Optionally, the output shaft is provided with a shaft shoulder and a clamping groove, a retaining ring is clamped in the clamping groove, the two axial sides of the first bearing respectively abut against the shaft shoulder and the retaining ring, and the second bearing is located between the first bearing and the shaft locking mechanism.

[0022] The utility model has the following technical effects:

[0023] The present utility model provides an electric tool, on the outer wall of the output shaft, there are provided a first locking surface, an unlocking surface and a second locking surface, and the shapes of the first locking surface and the second locking surface are defined as arc surfaces capable of surface-to-surface contact with the locking pin. In this way, in the state where the shaft locking mechanism locks the output shaft, one of the first locking surface and the second locking surface is in surface-to-surface contact with the locking pin, which can effectively reduce or eliminate stress concentration at the contact between the locking pin and the output shaft, avoid wear of the output shaft resulting in slipping of the shaft locking mechanism, improve the reliability of the shaft lock, and enable the output shaft to withstand a greater torque. Description of the Drawings

[0024] Figure 1 is a structural cross-sectional view of the electric tool of the present utility model;

[0025] Figure 2 is an assembly structural cross-sectional view of the shaft locking mechanism and the output shaft when the locking pin of the present utility model is in the unlocking position;

[0026] Figure 3 is an assembly structural cross-sectional view of the shaft locking mechanism and the output shaft when the locking pin of the present utility model is in the locking position;

[0027] Figure 4 is a partial structural cross-sectional view of the electric tool of the present utility model;

[0028] Figure 5 is a partial structural perspective view of the electric tool of the present utility model;

[0029] Figure 6 is a partial structural exploded view of the electric tool of the present utility model.

[0030] Description of the Reference Numerals

[0031] 100, electric tool;

[0032] 1, housing;

[0033] 2, motor;

[0034] 3, output shaft; 31, convex portion; 311, first locking surface; 312, unlocking surface; 313, second locking surface; 32, concave portion; 33, shaft shoulder; 34, card slot;

[0035] 4, shaft locking mechanism; 41, locking ring; 42, chamber; 43, shaft lock frame; 431, convex platform; 4311, convex structure; 44, locking pin;

[0036] 5, gap; 51, circumferential gap; 52, axial gap;

[0037] 6, first bearing;

[0038] 7. Second bearing;

[0039] 8. Retaining ring;

[0040] 9. Retaining plate. Detailed implementation manner

[0041] In order to make the technical solutions and beneficial effects of the present utility model more obvious and understandable, the following will be described in detail by listing specific embodiments. Unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application belongs.

[0042] In the description of the present utility model, unless otherwise clearly defined, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of the simplified description of the present utility model, rather than indicating that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, that is, it cannot be understood as a limitation to the present utility model.

[0043] In the present utility model, the terms "first" and "second" are only used for the purpose of clear description, and cannot be understood as the relative importance of the indicated features or the number of the indicated technical features. Therefore, the features defined with "first" and "second" can clearly include at least one of such features. In the description of the present utility model, the meaning of "a plurality" is at least two; the meaning of "several" is at least one; unless otherwise clearly defined.

[0044] In the present utility model, unless otherwise clearly defined, the terms "installation", "connection", "connection", "fixation", "setting", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection or an integral molding; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can also be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0045] In the present utility model, unless otherwise clearly defined, when a first feature is "on", "above", "over", "upon", "under", "beneath", "below", or "underneath" a second feature, it may be that the first feature is in direct contact with the second feature, or the first feature and the second feature are in indirect contact through an intermediate medium. Moreover, when the first feature is "above", "over", or "upon" the second feature, it may be that the first feature is directly above or obliquely above the second feature, or it merely indicates that the horizontal height of the first feature is higher than that of the second feature. When the first feature is "under", "beneath", or "below" the second feature, it may be that the first feature is directly below or obliquely below the second feature, or it merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0046] In the present utility model, the "front" and "rear" mentioned herein are both based on the markings in Figure 1 .

[0047] The following will Figures 1 to 6 describe in detail the power tool of the present utility model.

[0048] In the present embodiment, as Figures 1 to 6 shown, the power tool 100 includes a housing 1, a motor 2, an output shaft 3, and a shaft locking mechanism 4. The output shaft 3 is used to drive the tool head to operate. The shaft locking mechanism 4 includes a locking ring 41, a shaft locking bracket 43, and a locking pin 44. The locking ring 41 is installed on the housing 1 and is fixed. The locking ring 41 is disposed around the output shaft 3. A chamber 42 is formed between the inner wall of the locking ring 41 and the outer wall of the output shaft 3. The locking pin 44 is located in the chamber 42. The shaft locking bracket 43 is driven by the motor 2. The shaft locking bracket 43 includes a boss 431. The boss 431 extends into the chamber 42 and is linked with the output shaft 3. The rotational driving force of the motor 2 is transmitted to the output shaft 3 through the boss 431 of the shaft locking bracket 43, thereby driving the output shaft 3 to rotate and driving the tool head to operate. As Figure 2 , Figure 3 and Figure 5 shown, one side outer wall of the output shaft 3 facing the locking pin 44 includes a first locking surface 311, an unlocking surface 312, and a second locking surface 313 arranged in sequence. Both the first locking surface 311 and the second locking surface 313 are arc surfaces. Of course, the first locking surface 311 may be a complete arc surface or may be composed of multiple arc surfaces. Similarly, the second locking surface 313 may be a complete arc surface or may be composed of multiple arc surfaces.

[0049] As Figure 2 shown, when the power tool 100 is operating normally, the motor 2 drives the shaft locking bracket 43 to rotate. The boss 431 of the shaft locking bracket 43 drives the output shaft 3 to rotate. During this process, the side wall of the boss 431 simultaneously pushes the locking pin 44 to move around the central axis of the output shaft 3, so that the locking pin 44 is always movably located between the unlocking surface 312 and the inner wall of the locking ring 41. Therefore, the locking pin 44 does not interfere with the rotation of the output shaft 3.

[0050] During the process of the motor 2 driving the shaft lock 43 and the output shaft 3 to rotate in the clockwise direction, as Figure 3 shown, if the output shaft 3 is subjected to a reaction force from the tool head and undergoes abnormal reverse rotation (counterclockwise rotation), the unlocking surface 312 disengages from the locking pin 44, and the output shaft 3 abnormally reverses until the first locking surface 311 abuts against the locking pin 44. Moreover, the first locking surface 311 and the locking pin 44 are in surface-to-surface contact. At this time, the locking pin 44 is jointly clamped by the first locking surface 311 and the inner wall of the locking ring 41, and the locking pin 44 cannot move, thereby locking the output shaft 3.

[0051] During the process of the motor 2 driving the shaft lock 43 and the output shaft 3 to rotate in the counterclockwise direction, if the output shaft 3 is subjected to a reaction force from the tool head and undergoes abnormal reverse rotation (clockwise rotation), the unlocking surface 312 disengages from the locking pin 44, and the output shaft 3 abnormally reverses until the second locking surface 313 abuts against the locking pin 44. Moreover, the second locking surface 313 and the locking pin 44 are in surface-to-surface contact. At this time, the locking pin 44 is jointly clamped by the second locking surface 313 and the inner wall of the locking ring 41, and the locking pin 44 cannot move, thereby locking the output shaft 3.

[0052] By adopting the above technical solution, a first locking surface 311, an unlocking surface 312, and a second locking surface 313 are provided on the outer wall of the output shaft 3, and the shapes of the first locking surface 311 and the second locking surface 313 are defined as arc surfaces that can be in surface-to-surface contact with the locking pin 44. In this way, when the shaft locking mechanism 4 locks the output shaft 3, one of the first locking surface 311 and the second locking surface 313 is in surface-to-surface contact with the locking pin 44, which can effectively reduce or eliminate stress concentration at the contact between the locking pin 44 and the output shaft 3, avoid wear of the output shaft 3 resulting in slipping of the shaft locking mechanism 4, improve the shaft locking reliability, and enable the output shaft 3 to withstand a greater torque.

[0053] In one embodiment, as Figure 2 , Figure 3 and Figure 5 shown, the outer wall of the output shaft 3 includes a convex portion 31 and a concave portion 32 that are sequentially arranged along the circumferential direction of the output shaft 3. The convex portion 31 and the concave portion 32 are located at the rear end of the output shaft 3, and the first locking surface 311, the unlocking surface 312, and the second locking surface 313 are provided on the outer wall of the convex portion 31.

[0054] Furthermore, as Figure 2 and Figure 3 shown, the boss 431 is provided with a convex structure 4311 extending along the axial direction of the output shaft 3, and the convex structure 4311 extends into the concave portion 32. When the motor 2 drives the shaft lock 43 to rotate, the boss 431 circumferentially pushes the concave portion 32, thereby causing the boss 431 to drive the output shaft 3 to rotate together.

[0055] Furthermore, asFigure 2 and Figure 3 As shown, there are three protrusions 31 , which are evenly spaced apart and distributed along the circumference of the output value 3 , a recess 32 is formed between two adjacent protrusions 31 , and the shaft lock frame 43 is provided with three bosses 431 , and the protrusion structures 4311 are matched with the recesses 32 one by one.

[0056] Furthermore, if Figure 2 and Figure 3 As shown, a gap 5 is left between the circumferential side walls of the protruding structure 4311 and the recessed portion 32. Specifically, the gap 5 includes a circumferential gap 51 and an axial gap 52. When the output shaft 3 is subjected to the reaction force of the tool head and produces an abnormal reversal, the circumferential gap 51 is set and the size of the circumferential gap 51 is limited, and the shape, position and size of the first locking surface 311 and the second locking surface 313 are limited. The output shaft 3 is prevented from transmitting the torque to the boss 431 during the abnormal reversal of the output shaft 3 at a certain angle. In addition, the configuration of the axial gap 52 can reduce the friction generated between the abnormally reversed output shaft 3 and the boss 431.

[0057] In one embodiment, if Figure 2 and Figure 5 As shown, the first locking surface 311 and the second locking surface 313 are symmetrically arranged with respect to the axial direction of the output shaft 3 to facilitate structural design.

[0058] Furthermore, the ratio of the width of the first locking surface 311 to the width of the unlocking surface 312 is 1:1.5-1:3.

[0059] In one embodiment, the connection between the first locking surface 311 and the unlocking surface 312 is an arc surface, and the connection between the unlocking surface 312 and the second locking surface 313 is an arc surface, which is conducive to the smooth transition of the locking pin 44 between the corresponding locking surface and unlocking surface 312.

[0060] In one embodiment, if Figure 1 , Figures 4 to 6 As shown, the outer periphery of the output shaft 3 is sleeved with a first bearing 6 and a second bearing 7 , and the output shaft 3 is supported by the first bearing 6 and the second bearing 7 .

[0061] Furthermore, if Figures 4 to 6 As shown, the output shaft 3 is provided with a shaft shoulder 33 and a slot 34 , a retaining ring 8 is clamped in the slot 34 , the axial sides of the first bearing 6 are respectively in contact with the shaft shoulder 33 and the retaining ring 8 , and the second bearing 7 is located between the first bearing 6 and the shaft locking mechanism 4 .

[0062] In one embodiment, if Figure 4 and Figure 6 As shown, a blocking piece 9 is sleeved on the outer periphery of the output shaft 3 , and the blocking piece 9 abuts against the end surface of the lock ring 41 which is away from the shaft lock frame 43 to prevent the lock pin 44 from falling off.

[0063] It should be understood that the above embodiments are all exemplary and are not used to cover all possible implementation manners included in the claims. Without departing from the scope of the present disclosure, various deformations and changes can also be made on the basis of the above embodiments. Similarly, various technical features of the above embodiments can also be arbitrarily combined to form additional embodiments of the present utility model that may not be clearly described. Therefore, the above embodiments only represent several implementation manners of the present utility model and do not limit the protection scope of the utility model patent.

Claims

1. An electric tool comprising a housing (1), a motor (2), an output shaft (3) for driving a tool head to operate, and a shaft locking mechanism (4); characterized in that: The shaft locking mechanism (4) comprises: A locking ring (41) is mounted on the housing (1), wherein the locking ring (41) is arranged around the output shaft (3) and a chamber (42) is formed therebetween; A shaft lock frame (43), which is driven by the motor (2) and comprises a boss (431), wherein the boss (431) extends into the chamber (42) and is linked with the output shaft (3); a locking pin (44) located within the chamber (42); The outer wall of the output shaft (3) on one side facing the locking pin (44) comprises a first locking surface (311), an unlocking surface (312) and a second locking surface (313) which are arranged in sequence, and the first locking surface (311) and the second locking surface (313) are both arc surfaces; When the motor (2) drives the shaft lock frame (43) to rotate, the lock pin (44) can be movably located between the unlocking surface (312) and the inner wall of the lock ring (41), and the shaft lock frame (43) can drive the output shaft (3) to rotate; When the output shaft (3) is subjected to the reaction force of the tool head and produces an abnormal reversal, the first locking surface (311) or the second locking surface (313) and the inner wall of the locking ring (41) clamp the locking pin (44) toward each other, so that the locking pin (44) locks the output shaft (3); wherein, if the locking pin (44) abuts against the first locking surface (311), the two are in surface contact, and if the locking pin (44) abuts against the second locking surface (313), the two are in surface contact.

2. The electric tool according to claim 1, characterized in that: The outer wall of the output shaft (3) comprises a protrusion (31) and a recess (32) arranged in sequence along the circumferential direction, and the first locking surface (311), the unlocking surface (312) and the second locking surface (313) are arranged on the outer wall of the protrusion (31).

3. The electric tool according to claim 2, characterized in that: The boss (431) is provided with a protruding structure (4311) extending in the axial direction, and the protruding structure (4311) extends into the recessed portion (32), so that the boss (431) and the output shaft (3) are linked.

4. The electric tool according to claim 3, characterized in that: The number of the protrusions (31) is three and they are evenly spaced and distributed along the circumferential direction; the recessed portion (32) is formed between two adjacent protrusions (31); and the protrusion structure (4311) and the recessed portion (32) are arranged in a one-to-one matching manner.

5. The electric tool according to claim 3, characterized in that: A gap (5) is left between the circumferential side walls of the protruding structure (4311) and the recessed portion (32).

6. The electric tool according to any one of claims 1 to 5, characterized in that: The first locking surface (311) and the second locking surface (313) are arranged symmetrically with respect to the axial direction of the output shaft (3).

7. The electric tool according to claim 6, characterized in that: The ratio of the width of the first locking surface (311) to the width of the unlocking surface (312) is 1:1.5-1:

3.

8. The electric tool according to any one of claims 1 to 5, characterized in that: The connection between the first locking surface (311) and the unlocking surface (312) is a curved surface, and the connection between the unlocking surface (312) and the second locking surface (313) is a curved surface.

9. The electric tool according to any one of claims 1 to 5, characterized in that: The outer periphery of the output shaft (3) is sleeved with a first bearing (6) and a second bearing (7).

10. The electric tool according to claim 9, characterized in that: The output shaft (3) is provided with a shaft shoulder (33) and a clamping groove (34), a retaining ring (8) is clamped in the clamping groove (34), the axial sides of the first bearing (6) are respectively in contact with the shaft shoulder (33) and the retaining ring (8), and the second bearing (7) is located between the first bearing (6) and the shaft locking mechanism (4).

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