Three-row angular contact hub bearing assembly

Abstract

The invention discloses a three-row angular contact hub bearing assembly which comprises a flange inner ring and a flange outer ring, a ring body is arranged on the flange inner ring in a matched mode, a first roller path is arranged between the flange inner ring and the flange outer ring, and a second roller path and a third roller path are arranged between the flange outer ring and the ring body. A first rolling body is matched in the first raceway, a second rolling body is matched in the second raceway, a third rolling body is matched in the third raceway, the first rolling body is a tapered roller, and the second rolling body and the third rolling body are balls. The structure layout is compact, operation is more stable and reliable, the transmission efficiency and the bearing capacity are high, and the use requirement of an electric vehicle hub motor driving system is met.

Description

Three-row angular contact hub bearing assembly Technical Field

[0001] This invention relates to the field of automotive wheel hub bearing technology, and in particular to a three-row angular contact wheel hub bearing assembly. Background Technology

[0002] As a core component of the automotive chassis, wheel bearings are fundamental to the rotational motion of wheels and must simultaneously bear the radial and axial loads during vehicle operation. Their load-bearing capacity, structural rigidity, and operational reliability directly determine the safety and comfort of the vehicle, making them a core focus in the design and development of automotive chassis systems. With the rapid development of the new energy vehicle industry, in-wheel motor drive systems for electric vehicles have become an important development direction for electric vehicle drive systems due to their advantages such as short transmission paths, high space utilization, and fast power response. This has placed far more stringent requirements on the performance indicators and structural design of wheel bearings than on traditional gasoline vehicles. On the one hand, the increased weight of electric vehicles due to the inclusion of battery packs significantly increases the radial and axial loads that wheel bearings must withstand. On the other hand, the integration of the in-wheel motor into the wheel makes the wheel installation space more compact, requiring the bearings to have higher load-bearing capacity within a small volume and compact structure. Furthermore, the high-speed, high-torque operating characteristics of the in-wheel motor also place higher standards on the transmission efficiency, structural rigidity, and impact resistance of the bearings. Existing automotive wheel hub bearings are mostly based on double-row angular contact ball bearings, while some traditional fuel vehicles use a simple combination of roller bearings and ball bearings. These structures are ill-suited to the requirements of electric vehicle wheel hub motor drive systems, presenting numerous technical challenges, specifically: First, insufficient load-bearing capacity and susceptibility to impact failure: Due to structural design limitations, double-row angular contact ball bearings have a low basic rated dynamic load, making them unsuitable for the high-load conditions of electric vehicles. They are prone to impact failure under complex conditions such as vehicle start-up, emergency braking, and turning, resulting in significant operating noise and numerous after-sales issues. Furthermore, the simple combination design of roller and ball bearings fails to precisely match key parameters such as the dimensions and pitch circle diameter of each row of rolling elements, leading to severely uneven load distribution and excessive local stress in the bearings, further reducing overall load-bearing capacity and impact resistance. Secondly, poor overall rigidity and insufficient operational stability: Some existing wheel hub bearings use a split-processing and assembly design for their raceways, with each row of raceways being independently machined and assembled. This inevitably results in assembly gaps, leading to insufficient overall bearing rigidity. Under the high-speed, high-torque operating conditions of the wheel hub motor, radial and axial movement is prone to occur, affecting not only the stability of wheel rotation but also interfering with the power output of the wheel hub motor and reducing transmission efficiency. Thirdly, unreasonable contact angle design and unbalanced load distribution: Traditional wheel hub bearings often adopt a symmetrical contact angle design approach, failing to differentiate the design based on the actual stress conditions of each row of bearings. This results in an inability to achieve reasonable load distribution, causing some rows of bearings to bear excessive loads, accelerating bearing fatigue wear, significantly shortening bearing life, and reducing operational reliability.Fourth, low precision of the transmission interface leads to high torque transmission loss: Existing flange inner ring transmission interfaces mostly use ordinary flat or keyway connections, resulting in large clearances. This easily leads to slippage and clearance impacts during torque transmission, causing not only torque transmission loss and reduced transmission efficiency but also accelerated wear of bearing components, further affecting the bearing's structural rigidity and operational reliability. Fifth, mismatch between structural design and compact space requirements: Some existing technologies employ multi-row rolling element structures to improve bearing load capacity, but the overall design is cumbersome with too many separate components, resulting in excessively large bearing volumes. This makes it impossible to adapt to the compact space requirements of electric vehicle hub motor drive systems and to meet the integrated installation needs at the hub. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a three-row angular contact hub bearing assembly with a compact structure, more stable and reliable operation, high transmission efficiency and load-bearing capacity, meeting the usage requirements of hub motor drive systems in electric vehicles.

[0004] To achieve the above objectives, the present invention provides a three-row angular contact hub bearing assembly, including an inner flange ring and an outer flange ring. A ring body is fitted on the inner flange ring. A first raceway is provided between the inner flange ring and the outer flange ring. A second raceway and a third raceway are provided between the outer flange ring and the ring body. A first rolling element is fitted in the first raceway, a second rolling element is fitted in the second raceway, and a third rolling element is fitted in the third raceway. The first rolling element is a tapered roller, and the second and third rolling elements are balls.

[0005] The beneficial effects of this design are as follows: the integrated raceway design of the flange outer ring, ring body, and flange inner ring integrates each row of raceways into its corresponding component, eliminating assembly gaps in separate raceways, significantly improving the overall structural rigidity of the bearing, effectively preventing radial and axial movement under high speed and high torque conditions, and ensuring wheel rotation stability. Here, the ring body is preferably secured with an interference fit, and then fixed by riveting and flanging the flange inner ring, achieving a gapless rigid connection between the ring body and the flange inner ring. This strengthens the overall structural integrity of the bearing, eliminates component movement problems, and further improves the bearing's operational stability and impact resistance. The combination structure of the first row of tapered roller bearings with the second and third rows of angular contact ball bearings utilizes the tapered roller bearings' ability to withstand high radial and axial combined loads to bear the main load, while combining the high speed and low friction advantages of the angular contact ball bearings to adapt to the wheel hub motor operating conditions, achieving complementary performance and balancing the bearings' high load-bearing capacity and high transmission efficiency, thus meeting the high load and high speed requirements of electric vehicles.

[0006] Furthermore, the pitch circle diameter Dpw2 of the second rolling element and the pitch circle diameter Dpw3 of the third rolling element satisfy Dpw2 / Dpw3<1, and the pitch circle diameter Dpw3 of the third rolling element is 5%-15% larger than the pitch circle diameter Dpw2 of the second rolling element.

[0007] The beneficial effects of this design are as follows: by designing the three rows of rolling elements to be asymmetrically distributed, and limiting the pitch circle diameter of the third row to be 5%-15% larger than that of the second row, precise matching of the rolling element pitch circle diameters is achieved. This allows the load distribution of the second and third rows of angular contact ball bearings to be adapted to their own structural characteristics, avoiding excessive load on a single row of bearings. At the same time, the asymmetrical pitch circle diameter design, combined with the three-row structure, further optimizes the overall load transmission path of the bearing, disperses local stress, improves the overall load-bearing capacity of the bearing, and effectively solves the problem of uneven load distribution in traditional bearings.

[0008] Furthermore, the diameters Dwe of the first rolling element, Dw2 of the second rolling element, and Dw3 of the third rolling element satisfy Dwe / Dw3<1 and Dw2 / Dw3<1; wherein, the diameter Dwe of the first row of rollers is 10%-30% smaller than the diameter Dw3 of the third row of steel balls, and the diameter Dw3 of the third row of steel balls is 10%-25% larger than the diameter Dw2 of the second row of steel balls.

[0009] The beneficial effects of this design are as follows: by precisely defining the diameter ratio of the three rows of rolling elements, the diameter of the rolling elements is matched with the stress requirements of each row of bearings. The first row of tapered roller bearings uses relatively small diameter rollers to suit its structural characteristics of bearing high combined loads. The second and third rows of angular contact ball bearings achieve a stepped load distribution through a diameter gradient design. This diameter matching design makes the stress on each row of rolling elements more uniform, avoids local stress concentration on the rolling elements, significantly reduces the probability of fatigue wear between the rolling elements and the raceway, improves the bearing's impact resistance and service life, and at the same time ensures the smooth rotation of the rolling elements at high speeds, maintaining the high transmission efficiency of the bearing.

[0010] Furthermore, the contact angles α1 of the first raceway, α2 of the second raceway, and α3 of the third raceway satisfy α1 < α3 and α2 < α3; where 12° ≤ α1 ≤ 30°, 15° ≤ α2 ≤ 35°, and 25° ≤ α3 ≤ 42°.

[0011] The beneficial effects of this design are as follows: The asymmetrical contact angle design, with the largest contact angle in the third raceway and sequentially matched contact angles in the first and second raceways, and the limitation of the contact angle range for each row, ensures precise matching between the contact angle and the actual stress conditions of each row of bearings. The large contact angle design in the third row significantly enhances its axial load-bearing capacity, while the adaptive contact angle design in the first and second rows balances radial load bearing capacity with high-speed smoothness. The asymmetrical contact angle design achieves a reasonable distribution of radial and axial loads on the bearings, preventing some rows of bearings from bearing overload due to unreasonable contact angles. This effectively solves the problem of unbalanced load distribution in traditional symmetrical contact angle bearings, improving the overall load-bearing capacity and operational stability of the bearings.

[0012] Furthermore, the basic rated dynamic load Cr1 formed by the first raceway and the first rolling element, the basic rated dynamic load Cr2 formed by the second raceway and the second rolling element, and the basic rated dynamic load Cr3 formed by the third raceway and the third rolling element satisfy Cr1 > Cr3 > Cr2.

[0013] The beneficial effects of this design are as follows: by limiting the distribution relationship of the basic rated dynamic load Cr1 > Cr3 > Cr2, the rated dynamic load of each row of bearings is fully matched with its own structural characteristics and actual stress conditions. The first row of tapered roller bearings serves as the main load-bearing structure and is set with the maximum basic rated dynamic load to bear the main radial and axial combined loads. The third row of angular contact ball bearings is adapted to the secondary load, and the second row is adapted to light loads. This load distribution design achieves a reasonable distribution of bearing loads, eliminates local overload problems, effectively reduces the fatigue wear rate of each row of bearings, improves the overall load-bearing capacity, impact resistance and service life of the bearings, and ensures the stable operation of the bearings under complex working conditions such as starting, braking and turning. Attached Figure Description

[0014] Figure 1 is a cross-sectional structural diagram of an embodiment of the present invention; Figure 2 is a layout diagram of an embodiment of the present invention. Detailed Implementation

[0015] An embodiment of the three-row angular contact wheel hub bearing assembly of the present invention is shown in Figures 1 and 2: A flange inner ring 1 and a flange outer ring 2, with a ring body 3 fitted onto the flange inner ring 1. A first raceway 41 is provided between the flange inner ring 1 and the flange outer ring 2. A second raceway 42 and a third raceway 43 are provided between the flange outer ring 2 and the ring body 3. A first rolling element is fitted into the first raceway 41, a second rolling element into the second raceway 42, and a third rolling element into the third raceway 43. The first rolling element is a tapered roller, and the second and third rolling elements are balls. The flange outer ring 2 is a one-piece forged structure, integrating the machined raceway and flange connection structure. The flange connection structure has evenly distributed bolt holes for connection with the wheel. The connection is rigid at the end, with no gap between the parts. The ring body 3 is a precision-machined part with integrated machining raceways. The inner hole of the ring body 3 and the shaft of the inner ring 1 of the flange are assembled with an H7 / p6 interference fit, resulting in no radial clearance after assembly. The end of the inner ring 1 of the flange is formed by CNC riveting to create a flange structure. The flange structure fits tightly with the end face of the ring body 3, achieving axial fixation of the ring body 3. After riveting, the flange end face is precision milled to form an end face spline structure, which serves as the transmission interface on the motor side, replacing the traditional keyway connection. Furthermore, the second rolling element pitch circle diameter Dpw2 is 120mm, and the third rolling element pitch circle diameter Dpw3 is 130mm. The first rolling element pitch circle diameter is designed to be 115mm, forming an asymmetrical distribution with the second and third rows. The diameters of the first rolling element (Dw2) are 18 mm, the second rolling element (Dw2) are 20 mm, and the third rolling element (Dw3) is 24 mm. The contact angles of the first row (α1) are 20°, the second row (α2) are 25°, and the third row (α3) are 35°, achieving an asymmetric contact angle configuration where α1 < α3 and α2 < α3. By optimizing the raceway curvature radius, the number of rolling elements, and the material properties, the rolling elements are made of SUJ2 high-carbon chromium bearing steel, which, after quenching, achieves a hardness of HRC62-66. This ensures that the basic rated dynamic loads of each row satisfy Cr1 > Cr3 > Cr2, specifically Cr1 = 850 kN, Cr3 = 620 kN, and Cr2 = 480 kN.

[0016] The above examples are merely one preferred embodiment of the present invention. Ordinary variations and substitutions made by those skilled in the art within the scope of the technical solution of the present invention are all included within the protection scope of the present invention.

Claims

1. A three-row angular contact hub bearing assembly, comprising an inner flange ring and an outer flange ring, wherein a ring body is fitted onto the inner flange ring, characterized in that: A first raceway is provided between the inner ring and the outer ring of the flange, and a second raceway and a third raceway are provided between the outer ring and the ring body. A first rolling element is fitted in the first raceway, a second rolling element is fitted in the second raceway, and a third rolling element is fitted in the third raceway. The first rolling element is a tapered roller, and the second and third rolling elements are balls.

2. The three-row angular contact hub bearing assembly according to claim 1, characterized in that: The pitch circle diameter Dpw2 of the second rolling element and the pitch circle diameter Dpw3 of the third rolling element satisfy Dpw2 / Dpw3<1, and the pitch circle diameter Dpw3 of the third rolling element is 5%~15% larger than the pitch circle diameter Dpw2 of the second rolling element.

3. The three-row angular contact hub bearing assembly according to claim 1, characterized in that: The diameters Dwe of the first rolling element, Dw2 of the second rolling element, and Dw3 of the third rolling element satisfy Dwe / Dw3<1 and Dw2 / Dw3<1; wherein, the diameter Dwe of the first row of rollers is 10%~30% smaller than the diameter Dw3 of the third row of steel balls, and the diameter Dw3 of the third row of steel balls is 10%-25% larger than the diameter Dw2 of the second row of steel balls.

4. The three-row angular contact hub bearing assembly according to claim 1, characterized in that: The contact angles α1 of the first raceway, α2 of the second raceway, and α3 of the third raceway satisfy α1 < α3 and α2 < α3; where 12° ≤ α1 ≤ 30°, 15° ≤ α2 ≤ 35°, and 25° ≤ α3 ≤ 42°.

5. The three-row angular contact hub bearing assembly according to claim 1, characterized in that: The basic rated dynamic load Cr1 formed by the first raceway and the first rolling element, the basic rated dynamic load Cr2 formed by the second raceway and the second rolling element, and the basic rated dynamic load Cr3 formed by the third raceway and the third rolling element satisfy Cr1 > Cr3 > Cr2.

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