Stress-optimized bearing system
By designing a tapered bearing system, the problem of mismatch between the rotor's center of gravity and the bearing support point was solved, achieving stress uniformity and improved lubrication in the bearing system, significantly extending service life and reducing noise.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUANGDONG SHENGHUI TECHNOLOGY CO LTD
- Filing Date
- 2025-07-04
- Publication Date
- 2026-06-19
AI Technical Summary
In traditional bearing systems, the mismatch between the rotor's center of gravity and the bearing support point leads to stress concentration, causing problems such as scratches on the shaft surface, burning of the bearing inner hole, and wear through the wear-resistant plates. Furthermore, under high-speed operating conditions, the friction pair wears severely, the lubricating oil film is prone to rupture, leading to jamming failures and excessive noise.
The design adopts a tapered shaft core and a tapered bearing inner hole matching design. The large end of the tapered shaft core supports the rotor's center of gravity. Axial step and wear-resistant plates are set. Combined with oil-impregnated bearings and precision turning powder metallurgy process, a lubricating oil retention area is formed. Plasma spraying wear-resistant layer is used to ensure that the rotor's center of gravity is located in the large end area inside the bearing.
It achieves uniform stress in the bearing bore, reduces wear rate of wear-resistant plates by 60%, improves lubrication, reduces jamming failure rate by 90%, reduces noise to ≤45dB, increases service life to ≥30,000 hours, and improves yield to 98%.
Smart Images
Figure CN224380168U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of ventilation and fan manufacturing technology, and in particular to a stress-optimized bearing system. Background Technology
[0002] In the field of ventilation equipment and fan manufacturing, traditional bearing systems generally suffer from the following technical defects:
[0003] Traditional shaft cores use a cylindrical design with a uniform diameter, leading to a mismatch between the rotor's center of gravity and the bearing support point. During operation, stress concentrates in the upper region of the bearing's inner bore, causing problems such as scratches on the shaft core surface, burning of the bearing inner bore, and wear-resistant plates, significantly shortening service life. The rigid contact between the shaft core and the bearing is prone to radial runout and axial movement, resulting in fan vibration and excessive noise (>55dB(A)), especially severe under high-speed conditions. The existing clearance design between the bearing inner bore and the shaft core is unreasonable, making the lubricating oil film prone to rupture during high-speed operation, exacerbating wear on the friction pair, and even causing bearing seizure. Utility Model Content
[0004] The main objective of this invention is to provide a stress-optimized bearing system, aiming to solve the problems caused by the mismatch between the rotor's center of gravity and the bearing support point due to the traditional cylindrical shaft design with a constant diameter. During operation, stress concentrates in the upper region of the bearing's inner bore, leading to problems such as surface scratches on the shaft core, burning of the bearing's inner bore, and wear-through of the wear-resistant plates, significantly shortening its service life. The rigid contact between the shaft core and the bearing easily generates radial runout and axial movement, causing fan vibration and excessive noise (>55dB(A)), especially severe under high-speed conditions. The existing bearing inner bore and shaft core clearance design is unreasonable, making the lubricating oil film prone to rupture during high-speed operation, exacerbating wear on the friction pair, and even causing bearing seizure.
[0005] To achieve the aforementioned objectives of this utility model, the first aspect of this utility model proposes a stress-optimized bearing system, comprising:
[0006] A tapered shaft has a large end and a small end, wherein the diameter of the large end is larger than the diameter of the small end.
[0007] The bearing that is matched with the tapered shaft core has an inner bore that is tapered to fit the shaft core.
[0008] The tapered shaft core is provided with a wear-resistant plate at its small end.
[0009] The bearing system is configured such that when the fan rotor is running, the rotor's center of gravity is located inside the bearing and corresponds to the large end region of the shaft core.
[0010] Furthermore, an axial step difference is formed between the large end of the shaft and the inner hole of the bearing, and the size range of the axial step difference is 0.05-0.3mm.
[0011] Furthermore, the wear-resistant sheet has a diamond-like carbon coating on its surface, and the coating thickness is 2-5 μm.
[0012] Furthermore, the bearing is an oil-impregnated bearing, with an inner bore taper angle α of 0.5°-3° and a tapered shaft core taper angle β satisfying β=α±0.2°.
[0013] Furthermore, it also includes a weight-reducing groove provided at the small end of the shaft core, the depth of which is 10%-25% of the shaft core diameter.
[0014] Beneficial effects:
[0015] 1. This utility model uses the large end of the tapered shaft core to support the rotor's center of gravity, and the small end to reduce the inertial load through the weight-reducing groove, thereby making the stress distribution in the bearing's inner hole more uniform, reducing the wear rate of the wear-resistant plates by more than 60%, and increasing the expected life to ≥30,000 hours.
[0016] 2. This utility model forms a lubricating oil retention area through an axial step structure, which, combined with the capillary penetration effect of the oil-impregnated bearing, ensures continuous lubrication under high-speed conditions and reduces the seizure failure rate by 90%.
[0017] 3. This utility model achieves micron-level fit precision between the tapered shaft core and the bearing inner hole by combining precision turning and powder metallurgy processes, with a tolerance zone of H6 / h5 and a yield rate of over 98%.
[0018] 4. By setting a plasma-sprayed wear-resistant layer with a thickness of 2-5μm and Ra≤0.1μm, the friction coefficient of the wear-resistant sheet is reduced to 0.08-0.12, thus avoiding the environmental pollution problems of traditional electroplating processes. Attached Figure Description
[0019] Figure 1 This is a front view schematic diagram of a stress-optimized bearing system according to an embodiment of the present invention;
[0020] Figure 2 This is a top view schematic diagram of a stress-optimized bearing system according to an embodiment of the present invention;
[0021] Figure 3 This is a stress-optimized bearing system according to an embodiment of the present invention. Figure 2 A schematic diagram of the first type of tapered shaft core in cross section of AA;
[0022] Figure 4 This is a stress-optimized bearing system according to an embodiment of the present invention. Figure 2 A schematic diagram of the second type of tapered shaft core in cross section of AA;
[0023] Figure 5 This is a stress-optimized bearing system according to an embodiment of the present invention. Figure 2 A schematic diagram of the third type of tapered shaft core in cross section of AA;
[0024] Figure 6 This is a schematic diagram of the conventional structure of a tapered shaft core in existing technology.
[0025] in:
[0026] 7-Coiled shaft core; 701-Large end of shaft core; 702-Small end of shaft core; 703-Weight reduction groove; 14-Bearing; 1401-Bearing inner hole; 15-Side tube of bracket; 19-Wear-resistant plate; 20-Wind impeller hub.
[0027] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0028] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.
[0029] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly and specifically defined.
[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0031] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0032] Reference Figures 1-6 An embodiment of this utility model provides a stress-optimized bearing system, comprising:
[0033] The tapered shaft core 7 has a large end 701 and a small end 702, wherein the diameter of the large end 701 is larger than the diameter of the small end 702.
[0034] The bearing 14, which is matched with the tapered shaft core 7, has an inner bore 1401 that is tapered and adapted to the shaft core.
[0035] The tapered shaft core 7 is provided with a wear-resistant plate 19 at its small end 702;
[0036] The bearing system is configured such that when the fan rotor is running, the rotor's center of gravity is located inside the bearing 14 and corresponds to the area of the large end 701 of the shaft core.
[0037] In this embodiment, the diameter of the large end 701 of the tapered shaft core 7 is larger than the diameter of the small end 702, and its taper angle β is 0.5°-3°. The tapered shaft core 7 is manufactured using high-precision machining technology, and its surface is heat-treated (such as carburizing and quenching) to improve hardness and wear resistance.
[0038] The inner bore 1401 of the bearing 14 has a tapered structure with a taper angle α of 0.5°-3°, and satisfies β=α±0.2° to ensure a tight fit between the tapered shaft core 7 and the bearing 14. The bearing 14 is manufactured using powder metallurgy, with a porosity controlled at 8%-12% to achieve oil lubrication.
[0039] Wear-resistant plate 19 is set at the large end 701 of the tapered shaft core 7 to bear the high stress area when the fan rotor is running.
[0040] The center of gravity of the fan rotor is located inside the bearing 14, corresponding to the large end 701 area of the shaft core.
[0041] Optionally, an axial step is formed between the large end 701 of the shaft core and the inner hole of the bearing 14, and the size range of the axial step is 0.05-0.3mm.
[0042] An axial step difference is formed between the large end 701 of the shaft core and the inner hole of the bearing 14, with a step difference size of 0.05-0.3mm. This step difference is machined by precision turning and inspected by a laser interferometer to ensure that the step difference tolerance is ≤±0.01mm. The axial step difference design can distribute axial loads and reduce contact stress concentration.
[0043] The wear-resistant sheet 19 has a diamond-like carbon coating on its surface, and the coating thickness is 2-5 μm.
[0044] It should be noted that the wear-resistant plate 19 uses a diamond-like carbon coating with a thickness of 3μm and a surface friction coefficient ≤0.08. This diamond-like carbon coating is formed by plasma spraying and has a low friction coefficient ≤0.1 and high wear resistance, with a wear rate ≤0.01 mm³ / N·m.
[0045] The bearing 14 is an oil-impregnated bearing, with a taper angle α of 0.5°-3° for its inner bore 1401 and a taper angle β of 7 satisfying β=α±0.2°. The taper angle of 7 is preferably β=2°, the taper angle of the inner bore 1401 is α=1.8°, and the axial step difference is 0.15mm.
[0046] Optionally, it also includes a weight-reducing groove 703 provided at the small end 702 of the shaft core, the depth of which is 10%-25% of the diameter of the shaft core.
[0047] It should be noted that the depth of the weight-reducing groove 703 is 20% of the shaft core diameter. The weight-reducing groove 703 is machined using CNC milling technology, with a surface roughness Ra≤0.8μm. Therefore, the weight-reducing groove 703 reduces the rotational inertia of the rotor system and provides adjustment space for dynamic balance calibration.
[0048] In summary, the shape of the tapered shaft core 7 possesses the following characteristics: Figure 3 , Figure 4 and Figure 5 At least three.
[0049] A method for manufacturing stress-optimized bearing systems, including:
[0050] Step S1: The shaft blank is precision machined using a high-precision CNC lathe to form a tapered shaft 7 with a predetermined taper angle β. During machining, the cutting speed is controlled at 150-200 m / min, the feed rate is 0.1-0.2 mm / rev, and carbide inserts, such as TiAlN coated inserts, are used. After machining, the surface roughness Ra of the shaft is ≤0.4μm.
[0051] Step S2: The oil-impregnated bearing 14 is manufactured by powder metallurgy process, and the bearing inner hole 1401 matching the shaft core taper is formed simultaneously;
[0052] Step S2: Manufacture the oil-impregnated bearing 14 using powder metallurgy. Iron-based powder and graphite lubricant are mixed and pressed into shape. The particle size of the iron-based powder is ≤50μm, and the graphite lubricant accounts for 3%-5%. The sintering temperature is 1100-1200℃, and the holding time is ≥30min. After sintering, the inner hole 1401 of the bearing is tapered using electrical discharge machining to ensure that the taper angle α matches the tapered shaft core 7.
[0053] Step S3: Plasma spraying is performed on the surface of the large end 701 of the shaft core to form a wear-resistant layer. Spraying parameters include:
[0054] Spraying distance: 80-120mm;
[0055] Plasma power: 30-45kW;
[0056] Powder feeding rate: 25-40g / min;
[0057] Preheating temperature of the substrate: 150-200℃.
[0058] After spraying, the bonding strength between the wear-resistant layer and the substrate is ≥50MPa, and the coating quality is verified by microhardness test (HV0.3≥2000).
[0059] Step S4: After pressing the bearing 14 into the bracket tube 15, perform double-sided dynamic balancing calibration on surfaces P1 and P2. The calibration position is located in the weight reduction groove 703 area of the large end 701 and the small end 702 of the shaft core. The dynamic balancing equipment uses a photoelectric sensor, the calibration speed is 8000 rpm, and the error range is ≤ ±0.001 mm.
[0060] A ventilation device comprising a stress-optimized bearing system and a method for manufacturing the stress-optimized bearing system, wherein the ventilation device has a noise level ≤45dB when operating at full load.
[0061] One end of the tapered shaft core 7 is fitted with a fan impeller hub 20, which is fixed to the tapered shaft core 7 by an interference fit. The bearing 14 is made of copper-based powder metallurgy material with a porosity of 10% and an oil content of 15%-20%. Dynamic balancing is assisted by a laser vibration meter.
[0062] Explanation: The tapered shaft core 7 and the bearing inner hole 1401 of the bearing 14 are precisely tapered to form a wedge-shaped oil film and disperse contact stress, reducing the risk of local fatigue failure. The diamond-like carbon coating on the surface of the large end 701 of the shaft core works synergistically with the self-lubricating properties of the oil-impregnated bearing to significantly reduce friction loss, with a friction coefficient ≤0.1, thus improving wear resistance. The weight-reducing groove 703 on the small end 702 of the shaft core effectively suppresses vibration at high speeds ≥8000rpm by reducing the rotor's moment of inertia and, in conjunction with double-sided dynamic balancing calibration, ensures more stable operation and extends service life. Simultaneously, the fan rotor's center of gravity is located in the area of the large end 701 of the shaft core inside the bearing 14, further optimizing the dynamic load distribution. During manufacturing, CNC turning and powder metallurgy oil-impregnated bearings ensure assembly accuracy, plasma spraying strengthens the bonding strength of the wear-resistant layer, and rubber damping pads and sealing designs ensure operating noise ≤45dB and stability under high temperature and humidity conditions. This system achieves efficient drive, long service life, and adaptability to extreme environments for ventilation equipment through the synergistic effect of stress balancing, efficient friction reduction, and dynamic equilibrium.
[0063] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural or procedural transformations made based on the content of the present utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present utility model.
Claims
1. A stress-optimized bearing system, characterized in that, include: A tapered shaft (7) has a large end (701) and a small end (702), wherein the diameter of the large end (701) is larger than the diameter of the small end (702); The bearing (14) matched with the tapered shaft core (7) has a tapered inner hole (1401) that is adapted to the shaft core. The tapered shaft core (7) has a wear-resistant plate (19) provided at the small end (702) of the shaft core; The bearing system is configured such that when the fan rotor is running, the rotor's center of gravity is located inside the bearing (14) and corresponds to the area of the large end (701) of the shaft core.
2. The stress-optimized bearing system according to claim 1, characterized in that, An axial step difference is formed between the large end (701) of the shaft core and the inner hole of the bearing (14), and the size range of the axial step difference is 0.05-0.3mm.
3. The stress-optimized bearing system according to claim 1, characterized in that, The wear-resistant sheet (19) has a diamond-like carbon coating on its surface, and the coating thickness is 2-5 μm.
4. The stress-optimized bearing system according to claim 1, characterized in that, The bearing (14) is an oil-impregnated bearing, and the taper angle α of its bearing inner hole (1401) is 0.5°-3°, and the taper angle β of the tapered shaft core (7) satisfies β=α±0.2°.
5. The stress-optimized bearing system according to claim 1, characterized in that, It also includes a weight-reducing groove (703) provided at the small end (702) of the shaft core, the depth of which is 10%-25% of the diameter of the shaft core.