A new type of ball bearing for power tools

Abstract

A novel ball bearing for power tools, belonging to the field of bearing technology, includes a bearing outer sleeve, a bearing inner sleeve, steel balls, a cage, two sealing rings, a positioning platform, a power tool, an inner spacer, and an outer spacer. The inner and outer spacers are of equal height. The inner spacer is located at the left end of the inner sleeve, with its left end face abutting against the right end face of the inner spacer. The outer spacer is located at the left end of the bearing outer sleeve, with its left end face abutting against the right end face of the outer spacer. This forms an assembly structure consisting of the bearing outer sleeve, inner sleeve, inner spacer, and outer spacer. The bearing outer sleeve and inner sleeve are ensured to simultaneously contact the spacers under axial thrust F, achieving optimal bearing installation. When bearing surface A is subjected to axial thrust F, bearing surface B abuts against both the inner and outer spacers. The beneficial effects of this invention are: meeting the working clearance requirements of power tool bearings and achieving a long bearing life.

Description

Technical Field

[0001] This utility model relates to a ball bearing for power tools, and more particularly to a novel ball bearing for power tools, belonging to the field of bearing technology. Background Technology

[0002] Ball bearings for power tools, used in electric hammers, impact drills, and other specialized power tools.

[0003] The operating clearance of a bearing is a crucial factor affecting its service life, vibration, heat generation, and noise. In bearing application analysis and design, the preload applied to the bearing is an important design parameter. During bearing operation, as the temperature rises to thermal equilibrium, the bearing components expand due to thermal increase. This preload ensures that the bearing's operating clearance is appropriate and stable under thermal equilibrium conditions, allowing the bearing to operate normally.

[0004] However, power tool bearings are subjected to large radial loads during operation, and the loads can fluctuate greatly. The temperature rise during operation is uncertain, and the expansion of bearing parts is unpredictable. Therefore, conventional methods such as applying preload cannot meet the clearance requirements of power tool bearings and cannot achieve a long bearing life. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of existing ball bearings for power tools, which suffer from unpredictable operating temperature rise and component expansion when subjected to large instantaneous radial loads, thus failing to meet the requirements for working clearance and achieve a long bearing life. This invention provides a new type of ball bearing for power tools that can meet the requirements for working clearance and achieve a long bearing life when subjected to large instantaneous radial loads.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a novel ball bearing for power tools, comprising a bearing outer sleeve, a bearing inner sleeve, steel balls, a cage, two sealing rings, a positioning platform, and a power tool; the cage is disposed between the bearing outer sleeve and the bearing inner sleeve, and the cage can be a steel corrugated type, a riveted structure, or a nylon cage structure; the steel balls are disposed on the cage, and the two sealing rings are disposed at two ends of the bearing; the bearing has two surfaces, surface A and surface B; the sealing rings adopt a non-contact or light-contact sealing form; the positioning platform is disposed on the right side of the bearing inner sleeve, and the power tool is disposed on the right side of the positioning platform, with the left end of the power tool abutting against the positioning platform;

[0007] The power tool rotates a rotor, that is, the inner ring of the bearing rotates. When the power tool is working, the axial thrust F generated by drilling is transmitted to the bearing through the positioning table. The inner sleeve of the bearing protrudes from surface B by a amount b0 ≤ ±0.01mm. All the parts are made of bearing steel.

[0008] It also includes an inner spacer and an outer spacer, which are of equal height. The inner spacer is located at the left end of the inner sleeve of the bearing, with the left end face of the inner sleeve abutting against the right end face of the inner spacer. The outer spacer is located at the left end of the outer sleeve of the bearing, with the left end face of the outer sleeve abutting against the right end face of the outer spacer. This forms an assembly structure of the outer sleeve, inner sleeve, inner spacer, and outer spacer. This ensures that the outer sleeve and inner sleeve of the bearing contact the spacer simultaneously under the action of the axial thrust F. At this time, the bearing installation effect is optimal, the bearing working clearance is a slight negative clearance, and all rolling steel balls are in contact with the inner and outer sleeves of the bearing, resulting in the longest bearing service life.

[0009] When bearing surface A is subjected to axial thrust F, bearing surface B abuts against the inner and outer spacers, making the axial working clearance of the bearing slightly negative. All rolling steel balls are in contact with the inner and outer rings of the bearing, the bearing has the strongest load-bearing capacity, and the power tool operates well.

[0010] Conventional structures, unlike conventional ones, cannot meet the above requirements. If b0 > 0.01 mm, the gap between the bearing inner sleeve and the inner spacer is large, requiring a large axial thrust F for them to make contact. This can lead to premature bearing failure or seizure due to early overload, spiraling temperature rise, and accelerated wear. If b0 < -0.01 mm, the bearing inner sleeve and inner spacer make contact even without force. This results in a large axial clearance, incomplete contact between the balls and raceways, reduced bearing capacity, increased noise, or slippage and freewheeling.

[0011] In this example, the installation of the utility model can be performed by distinguishing the positioning surfaces. Generally, a mark is made on surface A to distinguish the mounting surfaces, which greatly reduces the installation difficulty, makes the installation of power tool bearings simple, and ensures good performance.

[0012] The bearing model is 6205-2RS, and the bearing dimensions are: inner diameter * outer diameter * width = 25 * 52 * 15 mm. The operating speed is 3000-5000 rpm.

[0013] The sealing ring can also be replaced by a dust cover; the sealing ring has good sealing performance and can effectively prevent the leakage of grease and the entry of external impurities. When operating at high speed, the sealing ring may generate heat and wear, which will lead to a decrease in sealing performance. Therefore, it is suitable for bearings with low speed and high sealing requirements; the dust cover is suitable for bearings that operate at high speed, can effectively prevent dust and moisture from entering the bearing, and can adapt to harsh working environments.

[0014] The radial clearance of bearing 6205-2RS is 20μm, the axial clearance is 160μm, and the single-sided protrusion of bearing 6205-2RS (with bearing A as the measurement reference) b0 = 90μm. Through special design and manufacturing of the inner ring of the above standard ball bearing 6205-2RS, such as off-groove design and manufacturing, or grinding the end face of the inner ring after the bearing is assembled, the above standard ball bearing 6205-2RS can achieve the purpose of protrusion b0 ≤ ±0.01mm.

[0015] The aforementioned bearing outer sleeve, bearing inner sleeve, inner spacer, and outer spacer assembly structure is also applicable to ball bearings for power tools where the bearing outer sleeve protrudes ≤ ±0.01mm on both surface B and surface A. When the bearing outer sleeve protrudes ≤ ±0.01mm on both surface B and surface A, the bearing can be installed arbitrarily without deliberately selecting a locating surface, ensuring its usability. In this case, the width difference between one end of the bearing outer sleeve and one end of the bearing inner sleeve is f1, and the width difference between the bearing outer sleeve and the bearing inner sleeve is 2f1.

[0016] The aforementioned bearing outer sleeve, bearing inner sleeve, inner spacer, and outer spacer assembly structure is also applicable to ball bearings for power tools of other models except for model 6205-2RS. For detailed assembly structure, please refer to the bearing outer sleeve, bearing inner sleeve, inner spacer, and outer spacer assembly structure of bearing 6205-2RS.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] When subjected to large instantaneous radial loads, the bearing clearance requirements of the power tool bearing are met to ensure that the bearing protrusion is within a certain range and to meet the axial clearance requirements of the bearing, so that the power tool bearing is easy to install and performs well.

[0019] To ensure optimal bearing installation, the bearing outer and inner rings must simultaneously contact the spacer under the axial thrust F. At this point, the bearing operating clearance is slightly negative, all rolling steel balls are in contact with both the inner and outer rings, resulting in the strongest bearing load capacity and the longest bearing service life. Attached Figure Description

[0020] Figure 1 Yes: Main sectional view of bearing 6205-2RS;

[0021] Figure 2 Yes: Assembly diagram of bearing 6205-2RS (bearing inner sleeve protrudes from the left end), positioning table, inner spacer and outer spacer;

[0022] Figure 3 Yes: Double-sided convex main sectional view of bearing 6205-2RS (Example 2).

[0023] Explanation of reference numerals in the attached drawings: 1. Bearing outer sleeve; 2. Bearing inner sleeve; 3. Steel ball; 4. Seal ring; 5. Cage; 6. Positioning platform; 7. Surface A; 8. Surface B; 9. Inner spacer; 10. Outer spacer. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] Example 1:

[0026] like Figures 1 to 2 As shown, a novel ball bearing for power tools, bearing model 6205-2RS, includes a bearing outer sleeve 1, a bearing inner sleeve 2, steel balls 3, two sealing rings 4, a cage 5, a positioning platform 6, and a power tool (not shown in the figure). The cage 5 is disposed between the bearing outer sleeve 1 and the bearing inner sleeve 2, and the cage 5 can be a steel corrugated type, a riveted structure, or a nylon cage 5 structure. The steel balls 3 are disposed on the cage 5, and the two sealing rings 4 are disposed at opposite ends of the bearing 2. The bearing has two surfaces, A surface 7 and B surface 8. The sealing rings 4 are constructed using a non-contact or light-contact sealing method. The positioning platform 6 is disposed on the right side of the bearing inner sleeve 2, and the power tool is disposed on the right side of the positioning platform 6, with the left end of the power tool abutting against the positioning platform 6.

[0027] The power tool rotates a rotor, that is, the inner ring of the bearing rotates. When the power tool is working, the axial thrust F generated by drilling is transmitted to the bearing through the positioning table 6. The inner sleeve of the bearing 2 has a protrusion b0 ≤ ±0.01mm on surface B 8. All the parts are made of bearing steel.

[0028] It also includes an inner spacer 9 and an outer spacer 10, which are of the same height. The inner spacer 9 is located at the left end of the inner sleeve 2 of the bearing, and the left end face of the inner sleeve 2 abuts against the right end face of the inner spacer 9. The outer spacer 10 is located at the left end of the outer sleeve 1 of the bearing, and the left end face of the outer sleeve 1 abuts against the right end face of the outer spacer 10. This forms the assembly structure of the outer sleeve 1, the inner sleeve 2, the inner spacer 9, and the outer spacer 10. This ensures that the outer sleeve 1 and the inner sleeve 2 of the bearing contact the spacers simultaneously under the action of the axial thrust F. At this time, the bearing installation effect is optimal, the bearing working clearance is a slight negative clearance, and all the rolling steel balls 3 are in contact with the inner and outer sleeves of the bearing, resulting in the longest service life of the bearing.

[0029] When bearing surface A 7 is subjected to axial thrust F, bearing surface B abuts against inner spacer 9 and outer spacer 10, giving the bearing a slight axial negative working clearance; ensuring that all rolling steel balls 3 are in contact with the inner and outer rings of the bearing during operation, the bearing has the strongest load-bearing capacity, and the power tool operates well.

[0030] Conventional structures, unlike conventional ones, cannot meet the above requirements. If b0 > 0.01 mm, the gap between the bearing inner sleeve 2 and the inner spacer 9 is large, requiring a large axial thrust F for them to make contact. This can lead to premature bearing failure or seizure due to early overload, spiraling temperature rise, and accelerated wear. If b0 < -0.01 mm, the bearing inner sleeve 2 and inner spacer 9 make contact even without force. This results in a large axial clearance, incomplete contact between the steel balls 3 and the raceway, reduced bearing load capacity, increased noise, or slippage and freewheeling.

[0031] In this example, the installation of the utility model can be carried out by distinguishing the positioning surfaces. Generally, a mark is made on surface A7 to distinguish the mounting surfaces, which greatly reduces the installation difficulty, makes the installation of the power tool bearing simple, and ensures good performance.

[0032] Bearing dimensions: inner diameter * outer diameter * width = 25 * 52 * 15 mm, operating speed: 3000-5000 rpm.

[0033] The sealing ring 4 has good sealing performance and can effectively prevent the leakage of lubricating grease and the entry of external impurities. When operating at high speed, the sealing ring 4 may generate heat and wear, which will lead to a decrease in sealing performance. Therefore, it is suitable for bearings with low speed and high sealing requirements. The dust cover is suitable for bearings operating at high speed and can effectively prevent dust and moisture from entering the bearing. It can adapt to harsh working environments.

[0034] The radial clearance of bearing 6205-2RS is 20μm, the axial clearance is 160μm, and the single-sided protrusion of bearing 6205-2RS (measured on bearing A surface 7) is b0 = 90μm. Through special design and manufacturing of the inner ring of the above standard ball bearing 6205-2RS, such as off-groove design and manufacturing, or grinding the end face of the inner ring after the bearing is assembled, the above standard ball bearing 6205-2RS can achieve the purpose of protrusion b0 ≤ ±0.01mm.

[0035] The assembly structure of bearing outer sleeve 1, bearing inner sleeve 2, inner spacer 9 and outer spacer 10 is also applicable to ball bearings for power tools of other models except 6205-2RS. For detailed assembly structure, please refer to the assembly structure of bearing outer sleeve 1, bearing inner sleeve 2, inner spacer 9 and outer spacer 10 of bearing 6205-2RS.

[0036] Example 2:

[0037] like Figure 3 As shown, the assembly structure of the bearing outer sleeve 1, bearing inner sleeve 2, inner spacer 9, and outer spacer 10 is also applicable to ball bearings for power tools where the bearing outer sleeve 1 has a protrusion b0 ≤ ±0.01mm on both surface B 8 and surface A 7. When the bearing outer sleeve 1 has a protrusion b0 ≤ ±0.01mm on both surface B 8 and surface A 7, the bearing can be installed arbitrarily without deliberately selecting the positioning surface, ensuring its usability. At this time, the width of one end of the bearing outer sleeve 1 differs from the width of one end of the bearing inner sleeve by f1, and the width of the bearing outer sleeve 1 differs from the width of the bearing inner sleeve 2 by 2 f1.

[0038] Same as Example 1.

[0039] The embodiments described above are merely preferred embodiments of this utility model. Ordinary variations and substitutions made by those skilled in the art within the scope of this utility model's technical solution should be included within the protection scope of this utility model.

Claims

1. A novel ball bearing for power tools, comprising a bearing outer sleeve, a bearing inner sleeve, steel balls, a cage, two sealing rings, a positioning platform, and a power tool; the cage is disposed between the bearing outer sleeve and the bearing inner sleeve; the steel balls are disposed on the cage, and the two sealing rings are disposed at two ends of the bearing; the bearing has two surfaces, surface A and surface B; the positioning platform is disposed on the right side of the bearing inner sleeve, and the power tool is disposed on the right side of the positioning platform, with the left end of the power tool abutting against the positioning platform; characterized in that: It also includes an inner spacer and an outer spacer, which are of the same height. The inner spacer is located at the left end of the inner sleeve of the bearing, with the left end face of the inner sleeve abutting against the right end face of the inner spacer. The outer spacer is located at the left end of the outer sleeve of the bearing, with the left end face of the outer sleeve abutting against the right end face of the outer spacer. This forms an assembly structure of the outer sleeve, inner sleeve, inner spacer, and outer spacer. This ensures that the outer sleeve and inner sleeve of the bearing contact the spacer simultaneously under the action of the axial thrust F, at which point the bearing installation effect is optimal. When bearing surface A is subjected to axial thrust F, bearing surface B comes into contact with the inner and outer spacers.

2. The novel ball bearing for power tools according to claim 1, characterized in that: Bearing model 6205-2RS, dimensions: inner diameter * outer diameter * width = 25 * 52 * 15 mm, operating speed: 3000-5000 rpm.

3. The novel ball bearing for power tools according to claim 1, characterized in that: The sealing ring has a dust cover structure.

4. A novel ball bearing for power tools according to claim 1, characterized in that: The aforementioned bearing outer sleeve, bearing inner sleeve, inner spacer, and outer spacer assembly structure is also applicable to ball bearings for power tools where the bearing outer sleeve protrudes ≤ ±0.01mm on both surface B and surface A. When the bearing outer sleeve protrudes ≤ ±0.01mm on both surface B and surface A, the bearing can be installed arbitrarily without deliberately selecting a positioning surface, ensuring its usability. In this case, the width difference between one end of the bearing outer sleeve and one end of the bearing inner sleeve is f1, and the width difference between the bearing outer sleeve and the bearing inner sleeve is 2f1.

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