Drill bushing structure of hammer pickaxe

Abstract

The drill bushing structure of the hammer pickaxe comprises a drill bushing body made of a first material, and the drill bushing body comprises a drill bit fixing end; the drill bit further comprises a nesting sleeve made of a second material, the nesting sleeve is fixed to the inner wall of the drill bit fixing end, the outer wall of the nesting sleeve is in interference fit with the inner wall of the drill bit fixing end, an annular outer clamping groove around the axis of the nesting sleeve is formed in the outer wall of the nesting sleeve, an annular inner clamping groove around the axis of the drill bit fixing end is formed in the inner wall of the drill bit fixing end, and the nesting sleeve is made of a second material. And an inner clamping spring is arranged between the annular outer clamping groove and the annular inner clamping groove so as to prevent the nesting from axially sliding. The technical scheme of the utility model has the advantages of low cost, good wear resistance and long service life, and effectively solves the existing technical defects.

Description

Technical Field

[0001] This application relates to the field of power tool technology, and in particular to a drill sleeve structure for a hammer pick. Background Technology

[0002] A drill bushing, also known as a spinneret, is a component on hammer drill power tools used to support and secure the impact drill bit or chisel. Traditional drill bushings are typically made of a single piece of homogeneous material, while the drill bit's material generally has higher wear resistance than the bushing. This results in less than ideal wear resistance for the bushing, and after a period of use, wear causes the drill bit to wobble beyond the standard requirement of 1-1.5mm, leading to substandard work accuracy and significantly increasing the user's workload.

[0003] As possible solutions, one is to make the entire drill bushing with a high wear-resistant material, which will greatly increase production and usage costs. The other is to replace the worn drill bushing in a timely manner. This method is often troublesome to disassemble and usually requires replacing the cylinder as well, which is also very costly. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application proposes a drill sleeve structure for a hammer pick, which has the advantages of low cost, good wear resistance, and long service life, thus solving the defects of existing technologies.

[0005] The technical solution adopted by this application to solve its technical problem is: a drill sleeve structure for a hammer pick, including a drill sleeve body made of a first material, the drill sleeve body including a drill bit fixing end; and a nest made of a second material, the nest being fixed on the inner wall of the drill bit fixing end.

[0006] In the above technical solution, the nested outer wall is further configured to have an interference fit with the inner wall of the drill bit fixing end.

[0007] In the above technical solution, the outer wall of the nest is provided with an annular outer groove around its axis, and the inner wall of the drill bit fixing end is provided with an annular inner groove around its axis. An inner retaining spring is provided between the annular outer groove and the annular inner groove to prevent the nest from sliding axially.

[0008] In the above technical solution, the drill bit fixing end is further provided with a drill bit fixing hole and an inner step, the nested inner edge is fixedly pressed against the inner step, and the nested outer edge is basically flush with the outer edge of the drill bit fixing end.

[0009] In the above technical solution, the distance between the maximum outer diameter of the drill bit fixing hole and the inner diameter of the nest is 0-1.5mm.

[0010] In the above technical solution, the first material is one of 40Cr, 20CrMnTi, and 35CrMo.

[0011] In the above technical solution, the second material is a high wear-resistant material of GCr15 or Cr12.

[0012] In the above technical solution, further, an annular sealing groove is provided at the end of the drill sleeve body away from the fixed end of the drill bit, and a sealing ring is provided on the sealing groove.

[0013] The beneficial effects of this application are: a highly wear-resistant material is embedded in the drill bit fixing end of the drill bushing, and the nest is used to keep in contact with the drill bit during use. Its overall service life is 2-3 times longer than that of traditional drill bushings, and can even reach the same service life as the whole machine, which greatly reduces the cost of use. Attached Figure Description

[0014] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0015] Figure 1 This is a schematic diagram of the external structure of this application.

[0016] Figure 2 This application is Figure 1 AA-direction structural decomposition diagram.

[0017] Figure 3 This application is Figure 1 AA-direction structural connection diagram.

[0018] Figure 4 This is a schematic diagram of the elevation structure of this application.

[0019] In the figure, 1. Drill bushing body, 11. Drill bit fixing end, 111. Annular inner groove, 12. Drill bit fixing hole, 13. Inner step, 2. Nesting, 21. Annular outer groove, 3. Snap ring, 4. Sealing groove. Detailed Implementation

[0020] like Figure 1-4 The image shows a specific embodiment of this application: a drill sleeve structure for hammer drills, used for mounting on power tools such as electric hammers, electric hammers, and impact drills. The drill sleeve structure includes a drill sleeve body 1 made of a first material and a nest 2 made of a second material. The drill sleeve body 1 includes a drill bit fixing end 11, and the nest 2 is fixed to the inner wall of the drill bit fixing end 11 by an interference fit.

[0021] To achieve self-locking during installation and further reinforce the structure, the outer wall of the nest 2 is provided with an annular outer groove 21 around its axis, and the inner wall of the drill bit fixing end 11 is provided with an annular inner groove 111 around its axis. An inner retaining spring 3 is provided between the annular outer groove 21 and the annular inner groove 111 to prevent the nest 2 from sliding axially. During installation, the retaining spring 3 is fitted onto the nest 2, and when the nest 2 is pressed into the predetermined position, the retaining spring 3 will automatically open into the annular inner groove, completing the automatic locking. This greatly strengthens the connection between the nest 2 and the drill bushing body 1, ensuring stability during use.

[0022] As a further technical feature, a drill bit fixing hole 12 and an inner step 13 are provided inside the drill bit fixing end 11. The inner edge of the nest 2 is fixedly pressed against the inner step 13, and the outer edge of the nest 2 is basically flush with the outer edge of the drill bit fixing end 11. Meanwhile, the distance H between the maximum outer diameter of the drill bit fixing hole 12 and the inner diameter of the nest 2 is set to 0-1.5 mm (see [reference]). Figure 4 This ensures that the drill bit's wobble will not exceed the standard requirement of 1-1.5mm during use.

[0023] As a key technical feature, in this embodiment, the material of the drill bushing body 1 is selected from 40Cr, 20CrMnTi, and 35CrMo; the material of the nest 2 is selected from the more wear-resistant GCr15 or Cr12 material.

[0024] 40Cr is a standard steel grade in China's GB standard, and it is one of the most widely used steels in the machinery manufacturing industry. After quenching and tempering, it possesses excellent comprehensive mechanical properties, good low-temperature impact toughness, and low notch sensitivity. The steel has good hardenability; it can be hardened to Ф28–60 mm by water quenching and to Ф15–40 mm by oil quenching. Besides quenching and tempering, this steel is also suitable for cyaniding and high-frequency quenching. It has good machinability; when the hardness is 174–229 HB, the relative machinability is 60%.

[0025] 20CrMnTi is a carburizing steel, typically a low-carbon steel with a carbon content of 0.17%-0.24%. It is widely used to manufacture transmission gears and shafts. As a medium-hardenability carburizing steel, CrMnTi exhibits high hardenability and, while ensuring hardenability, particularly high low-temperature impact toughness. 20CrMnTi is used for surface carburizing and hardening treatment. It has good machinability, minimal deformation during processing, and excellent fatigue resistance. It is well-suited for use in shaft products.

[0026] 35CrMo is the specification number for alloy structural steel (alloy quenched and tempered steel). This steel is mainly used to manufacture important parts in various machines that withstand impact, bending, torsion, and high loads. 35CrMo alloy structural steel has high static strength, impact toughness, and a high fatigue limit. Its hardenability is higher than that of 40Cr. It has high creep strength and endurance strength at high temperatures, and its long-term working temperature can reach 500℃. It has moderate plasticity during cold deformation and poor weldability. It can withstand temperatures down to -110 degrees Celsius and has high static strength, impact toughness, and high fatigue strength. It has good hardenability, no tendency to overheat, small quenching deformation, and acceptable plasticity during cold deformation. It has moderate machinability but exhibits first-type temper brittleness. Its weldability is poor, requiring preheating to 150~400 degrees Celsius before welding and post-weld heat treatment to relieve stress. It is generally used after quenching and tempering, but can also be used after high-frequency surface quenching or quenching followed by low- or medium-temperature tempering.

[0027] GCr15 steel is a high-carbon chromium bearing steel with low alloy content, good performance, and wide application. It has high wear resistance.

[0028] In addition, Cr12 is an alloy tool steel with good hardenability and good wear resistance. It is mainly used for cold stamping dies and punches, cold cutting shears, drill bushings, gauges, wire drawing dies, embossing dies, thread rolling dies, drawing dies and thread rolling dies, etc., which are subject to relatively small impact loads and require high wear resistance.

[0029] With the above settings, the material of the drill bushing body 1 can be selected as the first material with high strength but relatively low cost, while the nest 2, as the main contact part during operation, is selected as the second material with higher wear resistance. This satisfies the requirements of production and processing while reducing production and usage costs.

[0030] As a further technical feature, the end of the drill bushing body 1 away from the drill bit fixing end 11 is provided with an annular sealing groove 4, and a sealing ring (not shown in the figure) is provided on the sealing groove 4. This is designed to better prevent cylinder grease leakage.

[0031] Regarding other technical details, this drill bushing structure can be used to mount working heads such as drill bits or chisels. In this embodiment, an inner square bushing structure is selected, but a round bushing can also be used; this is not a limitation. The specific mounting method between the working head and the drill bushing is prior art and will not be elaborated upon here.

Claims

1. A drill sleeve structure for a hammer pick, comprising a drill sleeve body made of a first material, the drill sleeve body including a drill bit fixing end, characterized in that, It also includes a nest made of a second material, which is fixed to the inner wall of the drill bit fixing end; The outer wall of the nest is provided with an annular outer groove around its axis, and the inner wall of the drill bit fixed end is provided with an annular inner groove around its axis. An inner retaining spring is provided between the annular outer groove and the annular inner groove to prevent the nest from sliding axially.

2. A bit sleeve structure for a hammer pick according to claim 1, wherein The nested outer wall is interference-fitted with the inner wall of the drill bit fixing end.

3. A bit sleeve structure for a hammer pick according to claim 1 or 2, characterized in that The drill bit fixing end is provided with a drill bit fixing hole and an inner step inside. The nested inner edge is fixedly pressed against the inner step, and the outer edge of the nest is basically flush with the outer edge of the drill bit fixing end.

4. A bit sleeve structure for a hammer chisel according to claim 3, wherein The distance between the maximum outer diameter of the drill bit fixing hole and the inner diameter of the nested part is 0-1.5 mm.

5. The hammer bit of claim 1 wherein, The first material is one of 40Cr, 20CrMnTi, and 35CrMo.

6. The drill shoe structure of claim 1, wherein The second material is a high wear-resistant material, either GCr15 or Cr12.

7. The hammer bit of claim 1 wherein, The end of the drill bushing body away from the fixed end of the drill bit is provided with an annular sealing groove, and a sealing ring is provided on the sealing groove.

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