Drilling tool for machining safety hole of safety electric brush

Abstract

The utility model discloses a drilling cutter for processing a safety hole of a safety electric brush, which comprises a cutter bar and a cutter body, the cross section of the cutter body is in a parallelogram shape, so that when the cutter body drills the safety electric brush, a semicircular cavity convenient for discharging powder is formed between the cutter body and the safety electric brush; the tip end of the cutter body is provided with a groove used for machining an in-hole boss at the safety hole of the safety electric brush. The drilling tool is simple in structure, easy to machine, high in waste powder discharging efficiency, low in cost and high in efficiency, cutter feeding speed is high when a safety hole of a safety electric brush is machined at the same rotating speed, damage to the wall of the electric brush hole and an electric brush body is small, the perpendicularity of the machined safety hole meets the requirement, and a boss is easily machined in the safety hole and the diameter of the bottom of the boss is controllable. The machined safety electric brush is long in service life, the ejection rate of a safety component matched with the safety electric brush in the safety hole is high, and the safety electric brush is safer to use.

Description

Technical Field

[0001] This utility model relates to the field of machining, and in particular to a drilling tool for machining safety holes for safety brushes in motors. Background Technology

[0002] Safety structure brushes, a new type of brush that can protect the motor commutator from ablation during the final stage of brush use, are now widely used in power tool motor brushes. The processing of such brush safety structures is an important factor affecting the brush's stopping function and its failure rate.

[0003] In the past, the cutting tools used for machining safety holes were mostly single-pointed structures, such as drilling tools with a spiral outer wall and a slanted front end, to produce a shape like... Figure 10 The structure shown has a boss 1' at the center of the safety hole 3' in the safety brush 2'. During machining, the drilling tool is subjected to force on one side. The height of the boss inside the hole can be adjusted by changing the angle of the cutting edge, but the circumferential diameter of the boss's base cannot be adjusted. In industrial production, using this type of tool to machine the safety hole of a safety brush easily leads to structural defects at the safety hole, such as poor perpendicularity causing failure, or unreasonable boss dimensions. These issues frequently result in a high scrap rate for safety brush blanks, insufficient theoretical lifespan of the machined safety brushes, and a low ejection rate of the safety components used with the safety brush, leading to unsafe operation. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this utility model provides a drilling tool for machining safety holes in safety brushes. It has a simple structure, is easy to manufacture, and offers fast feed when machining safety holes at the same rotational speed, minimizing damage to the brush hole wall and brush body. The machined safety holes meet the required perpendicularity, and it is easy to machine bosses within the safety holes with controllable bottom diameters. It also boasts high waste powder removal efficiency, a long service life for the machined safety brushes, and a high ejection rate of the safety components used with it within the safety holes, resulting in safer operation.

[0005] To achieve the above-mentioned objectives of this utility model, this utility model provides a drilling tool for machining safety holes in safety brushes, comprising a tool shank and a tool body, wherein: the cross-section of the tool body is a parallelogram so that when the tool body drills a hole in the safety brush, a semi-circular cavity is formed between the tool body and the safety brush to facilitate the discharge of powder; the tip of the tool body is provided with a groove for machining an inner boss at the safety hole of the safety brush.

[0006] Preferably, the groove at the tip of the blade is a V-shaped groove.

[0007] Preferably, the outer edge of the V-shaped groove of the blade body is located close to the outer edge of the blade body so that the front part of the blade body forms a double tip.

[0008] Preferably, the edge of the V-shaped groove of the blade body is provided with a cutting edge to facilitate grinding of the safety brush.

[0009] Preferably, the tool holder is cylindrical, and the length of the tool holder is greater than or equal to the length of the tool body.

[0010] Preferably, the drilling tool is made of high-hardness tool steel.

[0011] Preferably, in the cross-section of the blade body, the length of the longer diagonal is equal to the diameter of the safety hole of the safety brush.

[0012] Preferably, the blade is a vertical plate-shaped blade.

[0013] Compared with the prior art, the drilling tool of this utility model for machining safety holes in safety brushes has the following advantages:

[0014] 1. This utility model relates to a drilling tool for machining safety holes in safety brushes. It has a simple structure, is easy to use, and is easy to process. When machining safety holes in safety brushes at the same speed, the feed rate is fast, causing less damage to the brush hole wall and the brush body. The perpendicularity of the machined safety hole meets the requirements. It is easy to machine a boss in the safety hole, and the bottom diameter of the boss is controllable. It has a high efficiency in removing waste powder, and the machined safety brush has a long service life. The safety components used with it have a high ejection rate in the safety hole, making it safer to use.

[0015] 2. This utility model relates to a drilling tool for machining safety holes in safety brushes. The cross-section of the tool body is parallelogram-shaped. When drilling a safety brush, a semi-circular cavity can be formed between the tool body and the safety hole, preventing congestion and compression during powder discharge and avoiding hole wall breakage. The V-shaped groove at the tip of the tool body can form a double-feed tip, different from the single-tip tip in existing technology. This facilitates rapid feed during drilling, reduces feed resistance and pressure on the hole wall, and allows for direct machining of the boss inside the safety hole during drilling. The boss has a reasonable size and structure, improving efficiency and the ejection rate when used with safety components, resulting in a longer service life and safer use for the safety brush. The tool body is a vertical plate-shaped tool body, resulting in high verticality of the machined safety hole, reducing the scrap rate of safety brush blanks and production costs.

[0016] The present invention will now be described in detail with reference to the accompanying drawings. Attached Figure Description

[0017] Figure 1 This is a front view of the drilling tool used in this utility model for machining safety holes in safety brushes;

[0018] Figure 2This is a left view of the drilling tool used in this utility model for machining safety holes in safety brushes;

[0019] Figure 3 This is a bottom view of the drilling tool used in this utility model for machining safety holes in safety brushes;

[0020] Figure 4 for Figure 1 Enlarged view of section A in the middle;

[0021] Figure 5 for Figure 2 Enlarged view of section B;

[0022] Figure 6 for Figure 2 Enlarged view of section C;

[0023] Figure 7 This is a first-view perspective view of the tip portion of the drilling tool used for machining safety holes in safety brushes according to this utility model.

[0024] Figure 8 This is a second perspective view of the tip portion of the drilling tool used for machining safety holes in safety brushes according to this utility model.

[0025] Figure 9 A schematic diagram showing the relative positions of the safety holes for the safety brush when machining the tool body;

[0026] Figure 10 This is a partial schematic diagram of the safety hole of the safety brush. Detailed Implementation

[0027] like Figures 1-3 The figures shown are schematic diagrams of different structures of drilling tools for machining safety holes in safety brushes provided by this utility model. Figures 1-3 It can be seen that the drilling tool for processing safety holes of safety brushes of this utility model includes a tool shank 1 and a tool body 2, wherein: the cross-section of the tool body is a parallelogram so that when the tool body drills the safety brush, a semi-circular cavity is formed between the tool body and the safety brush to facilitate the discharge of powder; the tip of the tool body is provided with a groove 3 for processing an inner boss at the safety hole of the safety brush.

[0028] The tool shank and tool body are made of high-hardness tool steel. The tool shank is cylindrical, and its length is greater than or equal to the length of the tool body. A chamfer is machined at the top of the tool shank (see [link]). Figure 1 , Figure 2 , Figure 6 The blade is a vertical, plate-shaped blade with a parallelogram-shaped cross-section (see [reference]). Figures 1-3 , Figure 9 Furthermore, the length of the longer diagonal of the blade's cross-section is equal to the diameter of the safety brush's safety hole. For example... Figures 3-5 , Figure 7 , Figure 8 As shown, the groove at the tip of the blade is a V-shaped groove, and the outer edge of the V-shaped groove is set close to the outer edge of the blade body so that the front of the blade body forms a double tip. The edge of the V-shaped groove is provided with a cutting edge for easy grinding of the safety brush.

[0029] Specifically, the tool holder of this utility model is cylindrical and is used to be clamped and fixed by the motor chuck so that the entire drilling tool rotates concentrically with the motor spindle. The tool holder is made of hard tool steel, which does not vibrate when rotating at high speed and does not deform when clamped.

[0030] The tool body and tool holder can be made of the same material, or a material with a higher hardness than the tool holder. High-hardness tool steel can prevent the tool body from deforming under stress, while also being more resistant to friction and having a longer service life. The tool body is mainly used for adjusting the drilling depth and machining the safety holes for safety brushes, allowing it to extend into the hole without damaging the hole wall. During the design phase, the length of the tool holder used for clamping should not be less than the length of the tool body to ensure stable tool body operation and facilitate adjustment of the drilling depth.

[0031] The cutting tool is a vertical flat plate with a parallelogram-shaped cross-section. Of the two diagonals on the cross-section, the longest diagonal is equal to the diameter of the safety hole in the safety brush. When the cutting tool drills a hole in the safety brush to create the safety hole, a semi-circular cavity can be formed between the cutting tool and the wall of the safety hole (e.g., ...). Figure 9 As shown, when the cutter rotates counterclockwise, the circular safety hole 3 can be divided into an upper part and a lower part along the longer diagonal 6 on the cutter body. The upper part includes an upper near-semicircle and a left arc-shaped part 5 located on the left side of the cutter body. The lower part includes a lower near-semicircle and a right arc-shaped part 4 located on the right side of the cutter body. Since the left arc-shaped part is smaller than the upper near-semicircle and the right arc-shaped part is smaller than the lower near-semicircle, the upper and lower parts can be regarded as approximately semicircles. When the cutter rotates at high speed, the drilled waste powder can be discharged through the semicircular cavity, thus preventing the congestion and compression of powder discharge during the drilling process, avoiding the cracking of the safety brush hole wall, improving the drilling quality, and reducing the scrap rate of the safety brush.

[0032] The tip of the cutter body is the cutting edge, used for drilling holes for safety brushes. A groove is provided at the front end of the cutter body to form an internal boss within the safety hole during drilling. The groove is a V-shaped groove (see...). Figures 1-5 , Figure 7 , Figure 8During machining, a V-shaped groove is machined inward from the flush front face of the parallelogram-shaped cutter body through turning or milling. The deepest point of the V-shaped groove is located in the middle of the cutter body's cross-section. A cutting edge is machined along the inclined edge of the V-shaped groove to facilitate grinding of the carbon material (i.e., the safety brush). Machining the V-shaped groove on the front face of the cutter body creates a double-feed tip (referred to as double-tip). Compared to existing single-tip cutters, the double-tip design of this invention allows for rapid tool feed, reducing feed resistance and pressure on the hole wall during drilling. Furthermore, the cutter body is subjected to balanced forces, preventing damage to the safety brush hole wall caused by rotational deformation due to centrifugal force during drilling.

[0033] During the design phase, cutting tools with V-grooves of varying depths can be designed based on the height of the bosses inside the safety holes of different safety brushes. This allows for the free selection of suitable tools capable of machining the required boss dimensions at the bottom of the hole, while ensuring that the tool holder structure and dimensions are identical for all tools. Typically, the V-groove depth can be between 0.3 and 0.5 mm.

[0034] Although the present invention has been described in detail above, the present invention is not limited thereto. Those skilled in the art can make modifications based on the principles of the present invention. Therefore, all modifications made in accordance with the principles of the present invention should be understood as falling within the protection scope of the present invention.

Claims

1. A drilling tool for machining safety holes in safety brushes, comprising a tool holder and a tool body, characterized in that: The cross-section of the blade is parallelogram-shaped so that when the blade drills a hole in the safety brush, a semi-circular cavity is formed between the blade and the safety brush to facilitate the discharge of powder. The tip of the cutter body is provided with a groove for machining an internal boss at the safety hole of the safety brush.

2. The drilling tool according to claim 1, characterized in that, The groove at the tip of the blade is a V-shaped groove.

3. The drilling tool according to claim 2, characterized in that, The outer edge of the V-shaped groove of the blade body is set close to the outer edge of the blade body so that the front part of the blade body forms a double tip.

4. The drilling tool according to claim 3, characterized in that, The edge of the V-shaped groove of the blade body is provided with a cutting edge to facilitate grinding of the safety brush.

5. The drilling tool according to any one of claims 1-4, characterized in that, The tool holder is cylindrical, and its length is greater than or equal to the length of the tool body.

6. The drilling tool according to claim 1, characterized in that, In the cross-section of the blade body, the length of the longer diagonal is equal to the diameter of the safety hole of the safety brush.

7. The drilling tool according to claim 1, characterized in that, The blade is a vertical, plate-shaped blade.

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