Electric tool

Abstract

The utility model discloses an electric tool which comprises a shell, an output shaft and a dustproof cover, the shell comprises an output shaft hole, and the output shaft hole comprises a dustproof cavity communicated with the outside; the output shaft penetrates through the output shaft hole, and the power output section of the output shaft extends out of the dustproof cavity to be connected with a load. The dustproof cover is located in the dustproof cavity, the dustproof cover and the inner wall of the dustproof cavity are arranged in a clearance mode, and the dustproof cover fixedly sleeves the output shaft and rotates synchronously with the output shaft. At least two labyrinth structures are formed between the dustproof cavity and the dustproof cover, each labyrinth structure comprises an annular groove formed in one of the dustproof cavity and the dustproof cover and an annular convex rib formed on the other one of the dustproof cavity and the dustproof cover, the annular convex rib partially extends into the annular groove, and a gap is formed between the annular convex rib and the annular groove. According to the electric tool provided by the utility model, the dustproof and waterproof effects of the output shaft hole are improved.

Description

Technical Field

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

[0002] For existing power tools, a dust-proof and / or waterproof structure is usually required to be provided on the output shaft to prevent foreign objects from entering the inside of the gearbox and contaminating the gearbox. Taking a angle grinder as an example, the dust-proof and / or waterproof structure is usually a dust-proof cover sleeved on the output shaft, and most of the dust-proof covers are made by stamping and bending metal plates. The dust-proof cover made of this metal plate material is expensive. Due to the manufacturing process and cost, there is generally only one bending process. When the angle grinder is in some water-bearing working conditions, the dust-proof and waterproof effects are not so ideal, and dust and water can easily enter the gearbox, causing the bearing to fall apart, the gear to wear, and the machine life to be shortened. Moreover, when using a metal material, surface rust prevention treatment is generally required, which further increases the cost. It is difficult to maintain the same dimensional accuracy of the blanking parts. Coupled with processes such as surface galvanizing and spraying, the dimensional deviation will be even greater, and the dust-proof / waterproof effect is not good.

[0003] Therefore, it is necessary to improve the existing technology to overcome the defects in the existing technology. Summary of the Utility Model

[0004] Therefore, what the utility model mainly solves is the technical problem that the dust-proof / waterproof effect of the dust-proof cover of the output shaft of the existing power tool is not good.

[0005] To solve the above technical problem, the utility model provides a power tool, including:

[0006] A housing, including an output shaft hole, and the output shaft hole includes a dust-proof cavity communicating with the outside;

[0007] An output shaft, passing through the output shaft hole, and a power output section of the output shaft extends out of the dust-proof cavity to connect a load;

[0008] A dust-proof cover, located in the dust-proof cavity, is arranged with a gap from the inner wall of the dust-proof cavity, the dust-proof cover is fixedly sleeved on the output shaft, and rotates synchronously with the output shaft;

[0009] At least two labyrinth structures are formed between the dust-proof cavity and the dust-proof cover, and the labyrinth structure includes an annular groove formed on one of the dust-proof cavity and the dust-proof cover and an annular rib on the other, and the annular rib partially extends into the annular groove, and there is a gap between the annular rib and the annular groove.

[0010] In one embodiment, the labyrinth structure includes a first labyrinth structure and a second labyrinth structure. The first labyrinth structure includes a first annular groove formed in the dust-proof cavity and a first annular rib formed in the dust-proof cover. The second labyrinth structure includes a second annular groove formed in the dust-proof cover and a second annular rib formed in the dust-proof cavity. The first annular groove is located radially outside the second annular groove, and one side wall is shared by the first annular rib and the second annular groove.

[0011] In one embodiment, a semi-labyrinth structure is further formed between the dust-proof cavity and the dust-proof cover. The semi-labyrinth structure includes a first semi-labyrinth structure located radially outside the first labyrinth structure. The first semi-labyrinth structure includes a bent flange formed in the dust-proof cover and a relief cavity formed in the dust-proof cavity. The bent flange extends into the relief cavity and has a gap with the relief cavity.

[0012] In one embodiment, the semi-labyrinth structure further includes a second semi-labyrinth structure located radially inside the second labyrinth structure. The second semi-labyrinth structure includes a concave corner formed in the dust-proof cover and a protruding portion formed on the inner wall of the dust-proof cavity. The protruding portion extends into the concave corner and has a gap with the concave corner.

[0013] In one embodiment, the angle of the concave corner is an obtuse angle, and the angle between two adjacent surfaces forming the protruding portion is the same as the angle of the concave corner.

[0014] In one embodiment, in the axial direction of the output shaft, the radial dimension of the dust-proof cover near the power output side is larger than the radial dimension of the dust-proof cover relatively far from the power output side.

[0015] In one embodiment, the dust-proof cover includes an inner ring portion sleeved on the output shaft. The power tool further includes a bearing sleeved on the output shaft, and one end of the inner ring portion near the power input side abuts against the inner ring of the bearing.

[0016] In one embodiment, the dust-proof cover is an integrally formed injection molding structure.

[0017] In one embodiment, the gaps between the inner wall of the dust-proof cavity and the dust-proof cover are uniform everywhere.

[0018] In one embodiment, the power tool further includes an output gear disposed in the housing and a bearing sleeved on the output shaft. The output shaft includes a gear mounting section for sleeving the output gear, a bearing mounting section for sleeving the bearing, and a dust cover mounting section for sleeving the dust cover. Wherein, the gear mounting section, the bearing mounting section, and the dust cover mounting section are arranged in sequence along the axial direction, and the diameters show an increasing trend.

[0019] A transition structure is formed between the gear mounting section and the bearing mounting section, and / or a transition structure is formed between the bearing mounting section and the dust cover mounting section.

[0020] Wherein, the transition structure is configured as an annular groove of the output shaft.

[0021] The technical solution provided by the present utility model has the following advantages:

[0022] In the power tool provided by the present utility model, at least two labyrinth structures are formed between the dust-proof cavity and the dust cover. Each labyrinth structure includes an annular groove formed on one of the dust-proof cavity and the dust cover and an annular rib formed on the other. The annular rib partially extends into the annular groove and has a gap with the annular groove. The multiple labyrinth structures make the path for external dust and / or water to reach the inside of the housing through the output shaft hole more tortuous and complex, which can hinder foreign matters such as dust and / or water from entering the inside of the housing through the output shaft hole, and improve the dust-proof / water-proof effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 It is a partial structure three-dimensional schematic diagram of the power tool provided by the embodiment of the present utility model;

[0025] Figure 2 For Figure 1 the exploded structure schematic diagram of the power tool shown;

[0026] Figure 3 For Figure 2 the enlarged structure schematic diagram of area A of the exploded structure schematic diagram of the power tool shown;

[0027] Figure 4 For Figure 2 the three-dimensional structure schematic diagram of another perspective of the dust cover of the power tool shown;

[0028] Figure 5 is Figure 1 a schematic cross-sectional structure diagram of a partial part of the power tool shown Specific embodiments

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other

[0030] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence

[0031] In the present invention, unless otherwise stated, the orientation terms such as "upper, lower, top, bottom" are usually in the direction shown in the drawings, or in the vertical, perpendicular or gravitational direction of the component itself; similarly, for the convenience of understanding and description, "inside, outside" refers to the inside and outside relative to the contour of each component itself, but the above orientation terms do not limit the present invention

[0032] This embodiment provides a power tool Figure 1 is a partial structure three-dimensional schematic diagram of the power tool provided by the embodiment of the present invention Figure 2 is Figure 1 a disassembled structure diagram of the power tool shown Figure 3 is Figure 2 an enlarged structure diagram of area A of the disassembled structure diagram of the power tool shown. Please refer to Figure 1 and Figure 2 , the power tool includes a housing 10, an output shaft 20 and a dust cover 30

[0033] In an exemplary implementation scenario, the above power tool is an angle grinder. An angle grinder is a grinding tool used for cutting and grinding, such as for cutting and grinding metals and stones, etc. Therefore, an angle grinder is also called a grinding machine or a disc grinder. In other exemplary implementation scenarios, the above power tool can be a grooving machine for grooving walls and floors, or the above power tool is a cutting machine for performing cutting work. For the convenience of understanding, this embodiment takes the power tool as an angle grinder as an example for description

[0034] The housing 10 includes a first housing 11 and a second housing 12. The first housing 11 and the second housing 12 are fixedly connected to each other, and a gear cavity for accommodating transmission gears is formed inside. Specifically, the first housing 11 and the second housing 12 are fastened and connected by bolts. An input shaft hole (not shown) is also provided on the first housing 11 for a power shaft to pass through it to drive the transmission gears to rotate.

[0035] The output shaft 20 penetrates through the second housing 12. One end is connected to the transmission gears, and the other end extends out of the housing 10 for connecting a load. Specifically, an output shaft hole 14 is provided on the second housing 12, and the output shaft 20 passes through the output shaft hole 14. The part of the output shaft 20 located inside the gear cavity serves as a power input section to connect the transmission gears, and the power output section of the output shaft 20 extends out of the second housing 12 for connecting a working head to drive the working head to perform a working task.

[0036] Among them, the working head matches the type of the power tool. When the power tool is an angle grinder, the working head can specifically be a grinding disc; when the power tool is a grooving machine, the corresponding working head can specifically be a cutting disc.

[0037] Please refer to Figure 2 and 3 As shown, the output shaft hole 14 includes a dust-proof cavity 140. The dust-proof cavity 140 is axially located between the power input section and the power output section of the output shaft 20 and is adjacent to the power output section and communicates with the outside. The dust-proof cover 30 is located in the dust-proof cavity 140. The dust-proof cover 30 is fixedly sleeved on the output shaft 20 and rotates synchronously with the output shaft 20. The dust-proof cover 30 is arranged with a gap from the inner wall of the dust-proof cavity 140 to ensure the normal rotation of the dust-proof cover 30 in the dust-proof cavity 140 and is also used to block liquids and / or dust from entering the gear cavity through the output shaft hole 14.

[0038] At least two labyrinth structures are formed between the dust-proof cavity 140 and the dust-proof cover 30. Each labyrinth structure includes a mutually cooperating annular groove and an annular rib. The annular rib partially extends into the annular groove, and there is a gap between the annular rib and the annular groove. One of the annular groove and the annular rib is formed in the dust-proof cavity, and the other is formed on the dust-proof cover. The mutually cooperating annular rib and annular groove form a labyrinth structure. Foreign objects such as dust and / or water need to change the direction by 180 degrees when passing through a labyrinth structure. Therefore, the labyrinth structure increases the path length and tortuosity of foreign objects entering the gear cavity and can provide good dust-proof and / or water-proof effects.

[0039] The number of labyrinth structures formed between the dust-proof cavity 140 and the dust-proof cover 30 is not limited. The more the number, the better the dust-proof / water-proof effect, but the radial dimension will be relatively large. In this embodiment, two labyrinth structures are taken as an example for illustration. Please refer to Figure 3 、 4 and Figure 5, two labyrinth structures are formed between the dust-proof cavity 140 and the dust-proof cover 30. Among them, the labyrinth structures include a first labyrinth structure and a second labyrinth structure. The first labyrinth structure includes a first annular groove 124 formed in the dust-proof cavity 140 and a first annular rib 31 formed in the dust-proof cover 30. The second labyrinth structure includes a second annular groove 32 formed in the dust-proof cover 30 and a second annular rib 121 formed in the dust-proof cavity 140. The first annular groove 124 is located radially outside the second annular groove 32, and one of the side walls is shared by the first annular rib 31 and the second annular groove 32. That is to say, the two labyrinth structures are arranged adjacent to each other. For foreign objects to pass through the two labyrinth structures continuously, they need to make two 180-degree turns, increasing the difficulty of passing through and improving the waterproof / dust-proof effect.

[0040] For the power tool provided in this embodiment, at least two labyrinth structures are formed between the dust-proof cavity and the dust-proof cover, increasing the difficulty for foreign objects to enter the gear cavity and improving the dust-proof / waterproof isolation effect of the dust-proof cover.

[0041] To further ensure the waterproof and dust-proof effect, in a specific embodiment, please refer to Figure 3 , 4 and Figure 5 , a semi-labyrinth structure is also formed between the dust-proof cavity 140 and the dust-proof cover 30. The semi-labyrinth structure includes a first semi-labyrinth structure located radially outside the first labyrinth structure (the first annular groove 124 and the first annular rib 31). Specifically, the first semi-labyrinth structure includes a bent flange 37 formed on the dust-proof cover 30 and a relief cavity 125 formed in the dust-proof cavity 140. The bent flange 37 extends into the relief cavity 125 and has a gap with the relief cavity 125. Specifically, the relief cavity 125 is an annular cavity protruding radially outward, and the relief cavity 125 is directly connected to the outside. The side of the relief cavity 125 close to the gear cavity is a stepped surface. The bent flange 37 is an annular rib protruding radially outward. The radially outer edge of the bent flange 37 exceeds the inner edge of the stepped surface, but there is a distance from the radially outer edge of the stepped surface. For foreign objects to pass through the first semi-labyrinth structure, they need to change the direction by approximately 90 degrees. The setting of the first semi-labyrinth structure can increase the difficulty for foreign objects to enter the gear cavity and improve the isolation effect.

[0042] The extension length of the first labyrinth structure (the first annular groove 124 and the first annular rib 31) radially outside is greater than that radially inside, and the bent flange 37 is formed on the side of the first annular rib 31 of the first labyrinth structure close to the power output.

[0043] In a specific embodiment, the semi-labyrinth structure further includes a second semi-labyrinth structure located radially inside the second labyrinth structure (the second annular groove 32 and the second annular rib 121). Specifically, the second semi-labyrinth structure includes a concave corner portion 36 formed on the dust cover 30 and a protruding portion 127 formed on the inner wall of the dust-proof cavity 140. The protruding portion 127 extends into the concave corner portion 140 and has a gap therebetween. The outer contour of the concave corner portion 36 is consistent with that of the protruding portion 127, and a tortuous interval is formed between the concave corner portion 36 and the protruding portion 127, further increasing the difficulty for foreign objects to pass through and ensuring the dust-proof / water-proof effect.

[0044] Specifically, the angle of the concave corner portion 140 is an obtuse angle. Correspondingly, the angle of the protruding portion 127 is the same as that of the concave corner portion 140. That is to say, the included angle between two adjacent surfaces forming the protruding portion 127 is consistent with the angle of the concave corner portion 36. In this way, in the axial direction, the bending angle of the gap formed between the concave corner portion 140 and the protruding portion 127 is an obtuse angle, which is beneficial to increasing the path length of the gap between the concave corner portion 140 and the protruding portion 127 and ensuring the dust-proof and water-proof effects.

[0045] In a specific embodiment, the dust cover itself is generally umbrella-shaped. In the axial direction of the output shaft 20, the radial dimension of the dust cover 30 near the power output side is larger than that of the dust cover 30 relatively far from the power output side. Define one end of the dust cover 30 near the power output side as the distal end, and the other end relatively far from the power output side as the proximal end. The outer contour of the distal end of the dust cover 30 is larger than that of the proximal end, which can provide a larger blocking surface at the distal end and also increase the path length for foreign objects to enter the gear cavity, improving the dust-proof and water-proof effects.

[0046] Please refer to Figure 5 , the power tool further includes a bearing 50 sleeved on the output shaft 20. The output shaft hole 14 further includes a bearing chamber, and the bearing 50 is arranged in the bearing chamber. In order to strengthen the positioning of the bearing 50, in one embodiment, the dust cover 30 includes an inner ring portion 33 sleeved on the output shaft 20. The inner ring portion 33 is fixedly sleeved on the output shaft 20 in a sleeve shape, and one end of the inner ring portion 33 near the power input side abuts against the inner ring of the bearing 50, so as to assist in supporting and positioning the bearing 50, decompose the acting force of the axial load of the bearing in the scenario of relatively large power, and extend the service life of the whole machine.

[0047] Specifically, please refer to Figure 2 and Figure 4, the labyrinth structure and the semi-labyrinth structure are arranged on the side of the dust cover 30 away from the power output. Preferably, reinforcing ribs 38 are arranged on the side of the dust cover 30 close to the power output. Preferably, the reinforcing ribs 38 extend radially and are arranged between the back side of the labyrinth structure and the semi-labyrinth structure and the outer side surface of the inner ring portion 33. That is to say, a dust-proof labyrinth structure is arranged on the side of the dust cover 30 away from the power output, and reinforcing ribs 38 are arranged on the side of the dust cover 30 close to the power output to improve the strength, ensure the dust-proof / water-proof effect, and make reasonable use of the space.

[0048] Please refer to Figure 5 , an output gear 60 is housed in the gear cavity for outputting power after deceleration. The output gear 60 is sleeved on the output shaft 20 and fixedly connected to the output shaft 20. The output shaft 20 includes a gear mounting section 21 for sleeving the output gear 60, a bearing mounting section 22 for sleeving the bearing 50, and a dust cover mounting section 23 for sleeving the dust cover 30. The gear mounting section 21, the bearing mounting section 22, and the dust cover mounting section 23 are arranged in sequence along the axial direction. To ensure the smooth assembly of the output gear and the bearing 50, the diameter of the gear mounting section 21 is smaller than the diameter of the bearing mounting section 22, and the diameter of the bearing mounting section 22 is smaller than the diameter of the dust cover mounting section 23. A transition structure is formed between the gear mounting section 21 and the bearing mounting section 22, and the transition structure is configured as an annular groove 25 of the output shaft 20. At this annular groove 25, the diameter of the output shaft 20 is smaller than the diameter of the gear mounting section 21. The annular groove 25 forms an avoidance space in the circumferential direction to avoid interference with the end of the output gear 60 and ensure the proper installation of the output gear 60.

[0049] Similarly, a transition structure is also formed between the bearing mounting section 22 and the dust cover mounting section 23, and this transition structure is also configured as an annular groove 26 of the output shaft 20. At this annular groove 26, the diameter of the output shaft 20 is smaller than the diameter of the bearing mounting section 22, so as to avoid interference between the stepped structure and the end of the bearing 50 and ensure the proper assembly of the bearing 50.

[0050] In a specific embodiment, the dust cover is an integrally formed injection-molded structure. Making the dust cover by injection molding can not only improve the dimensional accuracy of the dust cover, but also realize a more complex labyrinth structure to ensure the dust-proof / water-proof effect.

[0051] When the dimensional accuracy of the dust cover can be satisfied, the gap between the dust cover and the inner wall of the dust chamber can be controlled more precisely. Thus, on the premise of meeting the assembly gap, the gap can be narrowed as much as possible to improve the isolation effect. In a preferred embodiment, the gaps between the inner wall of the dust chamber 140 and the dust cover 30 are uniform everywhere, and the difficulty for foreign objects to pass through the gaps between the various sections of the dust chamber 140 and the dust cover 30 is roughly the same. Controlling the gap size more precisely can ensure the effect of isolating dust / liquid.

[0052] In summary, for the power tool provided by the present utility model, the dust-proof / water-proof effect of the output shaft hole is better, which can ensure the normal operation of the power tool in various environments.

[0053] Obviously, the above-described embodiments are only a part of the embodiments of the present utility model, rather than all of them. Based on the embodiments of the present utility model, those of ordinary skill in the art can make other different forms of changes or modifications without creative efforts, and all of them should fall within the protection scope of the present utility model.

Claims

1. An electric tool, characterized in that: include: The housing comprises an output shaft hole, wherein the output shaft hole comprises a dustproof cavity communicating with the outside; An output shaft passes through the output shaft hole, and a power output section of the output shaft extends out of the dustproof cavity to connect to a load; A dust cover is located in the dust-proof cavity and is provided with a gap with the inner wall of the dust-proof cavity. The dust cover is fixedly sleeved on the output shaft and rotates synchronously with the output shaft. At least two labyrinth structures are formed between the dustproof cavity and the dustproof cover, and the labyrinth structure includes an annular groove formed on one of the dustproof cavity and the dustproof cover and an annular rib on the other one, the annular rib partially extends into the annular groove, and there is a gap between the annular rib and the annular groove.

2. The electric tool according to claim 1, characterized in that: The labyrinth structure includes a first labyrinth structure and a second labyrinth structure, the first labyrinth structure includes a first annular groove formed in the dustproof cavity and a first annular rib formed in the dustproof cover, the second labyrinth structure includes a second annular groove formed in the dustproof cover and a second annular rib formed in the dustproof cavity, the first annular groove is located radially outside the second annular groove, and the first annular rib and the second annular groove share one of the side walls.

3. The electric tool according to claim 2, characterized in that: A semi-maze structure is also formed between the dustproof cavity and the dustproof cover, and the semi-maze structure includes a first semi-maze structure located radially outside the first maze structure, and the first semi-maze structure includes a bent flange formed on the dustproof cover and a yield cavity formed in the dustproof cavity, and the bent flange extends into the yield cavity and has a gap between the bent flange and the yield cavity.

4. The electric tool according to claim 3, characterized in that: The semi-maze structure also includes a second semi-maze structure located radially inward of the second maze structure, the second semi-maze structure including a concave corner portion formed on the dust cover and a protruding portion formed on the inner wall of the dustproof cavity, the protruding portion extending into the concave corner portion and having a gap between the protruding portion and the concave corner portion.

5. The electric tool according to claim 4, characterized in that: The angle of the concave corner portion is an obtuse angle, and the angle between two adjacent surfaces forming the protruding portion is the same as the angle of the concave corner portion.

6. The electric tool according to claim 1, characterized in that: In the axial direction of the output shaft, the radial dimension of the dust cover close to the power output side is greater than the radial dimension of the dust cover relatively far from the power output side.

7. The electric tool according to claim 1, characterized in that: The dust cover includes an inner ring portion sleeved with the output shaft, and the electric tool also includes a bearing sleeved on the output shaft, and one end of the inner ring portion close to the power input side abuts against the inner ring of the bearing.

8. The electric tool according to claim 1, characterized in that: The dust cover is an integrally formed injection-molded structure.

9. The electric tool according to claim 1, characterized in that: The gaps between the inner wall of the dustproof cavity and the dustproof cover are uniform at all locations.

10. The electric tool according to claim 1, characterized in that: The electric tool further comprises an output gear disposed in the housing, and a bearing sleeved on the output shaft, wherein the output shaft comprises a gear mounting section for sleeved the output gear, a bearing mounting section for sleeved the bearing, and a dust cover mounting section for sleeved the dust cover; wherein the gear mounting section, the bearing mounting section, and the dust cover mounting section are arranged in sequence along the axial direction, and their diameters are in an increasing trend; A transition structure is formed between the gear mounting section and the bearing mounting section, and / or a transition structure is formed between the bearing mounting section and the dust cover mounting section; Wherein, the transition structure is configured as an annular groove of the output shaft.

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