Combined bearing

Abstract

The application discloses a combined bearing, which comprises an inner ring, an outer ring, a cylindrical roller group and a retainer, first raceways and second raceways are arranged on the outer peripheral wall of the inner ring and the inner peripheral wall of the outer ring, the cylindrical roller group comprises a plurality of cylindrical rollers, the plurality of cylindrical rollers are divided into a plurality of radially loaded rollers and a plurality of axially loaded rollers, the plurality of radially loaded rollers and the plurality of axially loaded rollers are alternately staggered and arranged at an angle of 90 DEG, the radially loaded rollers are respectively arranged in contact with the two first raceways, and the axis of the radially loaded rollers is arranged in parallel with the axis of the inner ring; the axially loaded rollers are respectively arranged in contact with the two second raceways, and the axis of the axially loaded rollers is arranged in perpendicular to the axis of the inner ring. The application solves the problems that the traditional cylindrical roller bearing cannot simultaneously bear radial and axial loads, the rollers of the conventional crossed roller bearing are prone to skew and shift, the end face friction and wear are large, the bearing capacity is weak, and the structure assembly is complicated.

Description

Technical Field

[0001] This invention relates to the field of technology, specifically to a combined bearing. Background Technology

[0002] Cylindrical roller bearings are commonly used load-bearing components in mechanical transmissions. They transmit force through line contact between the cylindrical rollers and the inner and outer raceways, and are characterized by high load-bearing capacity, low coefficient of friction, and high speed. However, the rollers in traditional cylindrical roller bearings are mostly arranged in parallel, which can only mainly bear radial forces and is difficult to bear axial forces. If both radial and axial forces need to be borne simultaneously, it is usually necessary to combine cylindrical roller bearings with thrust bearings, or to use special bearing structures such as angular contact ball bearings.

[0003] However, using multiple bearings in combination increases the overall structural size and occupies more installation space, failing to meet the design requirements of miniaturized and compact equipment. While special bearings such as angular contact ball bearings can withstand bidirectional forces, their load-bearing capacity is weaker than that of cylindrical roller bearings, and their manufacturing process is complex and costly. Furthermore, although some existing crossed roller bearings can achieve bidirectional load-bearing, their cages are mostly split structures or single pocket designs, which cannot effectively guide the rollers to rotate in an orderly manner, easily leading to problems such as roller tilting, mutual friction, and jamming, affecting the bearing's rotational accuracy and service life. In addition, the installation of crossed roller bearing rollers is difficult, which is not conducive to mass production. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a combined bearing that solves the problems of traditional cylindrical roller bearings being unable to simultaneously bear radial and axial loads, while conventional crossed roller bearings suffer from roller misalignment and movement, high end-face friction and wear, weak load-bearing capacity, and cumbersome assembly.

[0005] To achieve the above objectives, the present invention provides a combined bearing, comprising an inner ring, an outer ring, a cylindrical roller assembly, and a cage for accommodating the cylindrical roller assembly. A first raceway and a second raceway are formed on the outer peripheral wall of the inner ring and the inner peripheral wall of the outer ring. The first and second raceways on the inner ring are perpendicularly connected to form an inner raceway, and the first and second raceways on the outer ring are perpendicularly connected to form an outer raceway. The cylindrical roller assembly is movably disposed between the outer and inner raceways. The cylindrical roller assembly includes a plurality of cylindrical rollers, which are divided into a plurality of radially loaded rollers and a plurality of axially loaded rollers. The radially loaded rollers and the axially loaded rollers are staggered and arranged at 90° intervals. Each radially loaded roller is in contact with two of the first raceways, and the axis of the radially loaded roller is parallel to the axis of the inner ring. Each axially loaded roller is in contact with two of the second raceways, and the axis of the axially loaded roller is perpendicular to the axis of the inner ring.

[0006] The advantages of adopting the above technical solution are as follows: In the above technology, the inner and outer rings are connected vertically to form an integrated L-shaped inner and outer raceway. The radially loaded rollers and the axially loaded rollers are arranged at 90° intervals and matched with their respective raceways. The radial roller axis is parallel to the bearing center axis so that it only bears the radial load, while the axial roller axis is perpendicular to the bearing center axis so that it only bears the axial load. This achieves the decoupling and independent transmission of radial and axial loads, thereby avoiding the load coupling interference problem of traditional 45° uniform contact angle rollers. The integrated inner and outer raceways can respectively constrain the assembly position of the two types of rollers, thereby improving the overall structural compactness of the bearing. It can simultaneously bear radial force, axial force and overturning moment without the need for multiple sets of bearings to be stacked and combined, thereby reducing the space occupied by equipment installation. This makes it suitable for the combined load conditions of precision rotation and low-frequency reciprocating rotation of robot joints, improving the smoothness of rotation operation and the overall load limit.

[0007] The present invention further provides that the diameter of the cylindrical roller is greater than the length of the cylindrical roller, and the formula for calculating the diameter of the cylindrical roller is Dw=ak*Lw, where Lw is the length of the roller, and ak is a coefficient with a range of 1.2-1.5.

[0008] The advantages of adopting the above technical solution are: the roller adopts a short and thick structure design with a diameter greater than its length. By limiting the matching ratio range of the roller diameter and length, the mechanical properties of the roller cross section are optimized. The short and thick roller configuration can improve the roller's own bending and torsional stiffness, thereby suppressing the roller from bending deformation and local skew under reciprocating combined loads. After the overall structural rigidity of the roller is improved, the stress distribution in the contact area between the roller and the raceway is more uniform, thereby eliminating the stress concentration phenomenon at both ends of the slender roller and reducing the probability of fatigue wear on the raceway and roller surfaces.

[0009] The present invention further comprises: the cage being composed of several beams, with a common pocket formed between adjacent beams; the common pockets being divided into several first pockets for accommodating radially loaded rollers and several second pockets for accommodating axially loaded rollers; the several first pockets and several second pockets being arranged alternately; the inner wall contour of each first pocket and each second pocket being adapted to the outer circumference of its corresponding cylindrical roller; and the radial cross-section of both the first pockets and the second pockets being rectangular.

[0010] The advantages of adopting the above technical solution are as follows: In the above technology, the cage is integrally formed by several beams, and the adjacent beams enclose staggered first pockets and second pockets. The inner wall of the rectangular cross-section pocket is adapted to the outer surface of the corresponding cylindrical roller, and the integrally formed beams improve the overall structural strength of the cage, thereby reducing the probability of cage deformation under load; the aforementioned alternating first pockets and second pockets precisely define the installation position of the radially loaded rollers and the axially loaded rollers, thereby ensuring the 90° staggered arrangement accuracy of the cylindrical rollers, while the inner wall of the pockets restricts the axial movement of the cylindrical rollers while reserving space for rotational movement; the aforementioned first pockets and second pockets physically separate the two types of cylindrical rollers, thereby preventing mutual friction and collision between the cylindrical rollers during operation, reducing the internal frictional resistance and operating temperature rise of the bearing.

[0011] The present invention further comprises: two first limiting pieces are provided at each of the first pockets, and each of the first limiting pieces is integrally connected to the adjacent beam; two second limiting pieces are provided at each of the second pockets, and each of the second limiting pieces is integrally connected to the adjacent beam; the first limiting pieces are perpendicular to the axis of the radially loaded roller, and the second limiting pieces are perpendicular to the axis of the axially loaded roller.

[0012] The advantages of adopting the above technical solution are as follows: The first limiting plate at the first pocket and the second limiting plate at the second pocket are integrally connected to the adjacent beam, without being separate independent components. This avoids the assembly gaps and potential loosening failures caused by a split structure. The first limiting plate's surface is perpendicular to the radially loaded roller axis, and the second limiting plate's surface is perpendicular to the axially loaded roller axis, thus directionally constraining the axial movement of the corresponding cylindrical roller and preventing abnormal contact between the cylindrical roller end face and the raceway. Furthermore, the first and second limiting plates are integrally formed with the beam, eliminating the need for separate assembly and fixing processes and reducing dimensional errors caused by assembly. The arrangement of the two limiting plates perpendicular to the roller axis evenly distributes the contact stress generated during operation, preventing localized stress concentration and damage. This ensures the cylindrical roller remains centered during operation and maintains the bearing's rotational accuracy for a long period.

[0013] The present invention further provides that: the two first limiting pieces of each first pocket are respectively configured to cooperate with the two second raceways with clearance.

[0014] The advantages of adopting the above technical solution are as follows: In the above technology, the two first limiting plates matching the same first pocket are respectively clearance-fitted with the second raceways of the inner ring and outer ring. The axial movement of the radially loaded rollers is restricted by the fit between the first limiting plates and the second raceways, thereby preventing the end faces of the radially loaded rollers from rubbing against the second raceways and avoiding abnormal wear on the end faces of the radially loaded rollers. The first limiting plates simultaneously constrain the overall axial displacement of the cage, stabilizing the assembly position of the cage relative to the inner and outer rings and preventing cage misalignment from disrupting the arrangement of the cylindrical rollers. Furthermore, the first limiting plates form a unified assembly datum based on the second raceways, thereby reducing the cage alignment adjustment steps during bearing assembly, thus improving the assembly consistency of batch products. They also evenly distribute the axial force generated by the reciprocating motion of the radially loaded rollers, reducing the local compressive strength of the second raceways, thereby delaying damage to the raceway surface and maintaining the bearing's rotational accuracy over the long term. The present invention further provides that: the two second limiting pieces of each second pocket are respectively configured to cooperate with the two first raceway gaps.

[0015] The advantages of adopting the above technical solution are as follows: In the above technology, the two second limiting plates matching the same second pocket are respectively clearance-fitted with the first raceway of the inner ring and the outer ring. The axial movement of the axially loaded roller is restricted by the cooperation between the second limiting plate and the first raceway, thereby preventing the end face of the axially loaded roller from rubbing against the first raceway and avoiding abnormal wear on the end face of the axially loaded roller. The second limiting plate simultaneously constrains the overall radial displacement of the cage, stabilizes the radial assembly position of the cage relative to the inner and outer rings, and prevents the cylindrical roller from tilting and jamming due to radial displacement of the cage. The second limiting plate forms a unified assembly datum based on the first raceway, unifies the cage installation positioning standard during batch assembly, reduces manual assembly dimensional errors, and evenly distributes the radial component force generated by the reciprocating motion of the axially loaded roller, thereby optimizing the contact stress distribution of the first raceway, reducing bearing operating friction loss and temperature rise, and extending the bearing fatigue service life. Attached Figure Description

[0016] Figure 1 This is an exploded three-dimensional view of the present invention; Figure 2 This is a front sectional view of the present invention; Figure 3 This is a partial three-dimensional view of the cage and cylindrical roller assembly state in this invention; Figure 4 This is a partial three-dimensional view of the cage in this invention; Figure 5 This is a partial cross-sectional view from the perspective of the axially loaded roller in this invention; Figure 6 This is a partial cross-sectional view from the perspective of the radially loaded roller in this invention. Detailed Implementation

[0017] This invention provides a combined bearing, comprising an inner ring 1, an outer ring 2, a cylindrical roller assembly, and a cage 3 for housing the cylindrical roller assembly. A first raceway 4 and a second raceway 41 are formed on the outer peripheral wall of the inner ring 1 and the inner peripheral wall of the outer ring 2. The first raceway 4 and the second raceway 41 on the inner ring 1 are perpendicularly connected to form an inner raceway 11, and the first raceway 4 and the second raceway 41 on the outer ring 2 are perpendicularly connected to form an outer raceway 21. The cylindrical roller assembly is movably disposed between the outer raceway 21 and the inner raceway 11. The cylindrical roller assembly includes a plurality of cylindrical rollers, which are divided into a plurality of radially loaded rollers 42 and a plurality of axially loaded rollers. Rollers 43, a plurality of radially loaded rollers 42 and a plurality of axially loaded rollers 43 are staggered and arranged at 90° intervals. The radially loaded rollers 42 are respectively in contact with two first raceways 4, and the axes of the radially loaded rollers 42 are relatively parallel to the axis of the inner ring 1. The axially loaded rollers 43 are respectively in contact with two second raceways 41, and the axes of the axially loaded rollers 43 are relatively perpendicular to the axis of the inner ring 1. The diameter of the cylindrical rollers is greater than the length of the cylindrical rollers. The formula for calculating the diameter of the cylindrical rollers is Dw=ak*Lw, where Lw is the length of the roller, and ak is a coefficient with a range of 1.2-1.5. The retainer 3 is composed of several beams 31, with a common pocket formed between adjacent beams 31. This common pocket is divided into several first pockets 32 for accommodating radially loaded rollers 42 and several second pockets 33 for accommodating axially loaded rollers 43. The first pockets 32 and second pockets 33 are arranged alternately. The inner wall contour of each first pocket 32 ​​and each second pocket 33 is adapted to the outer circumferential surface of its corresponding cylindrical roller. The radial cross-section of both the first pockets 32 and the second pockets 33 is rectangular. Each first pocket 32 ​​is provided with two first limiting pieces 321. The first limiting piece 321 is integrally connected to the adjacent beam 31. Two second limiting pieces 331 are provided at each second pocket 33. Each second limiting piece 331 is integrally connected to the adjacent beam 31. The first limiting piece 321 is perpendicular to the axis of the radially loaded roller 42. The second limiting piece 331 is perpendicular to the axis of the axially loaded roller 43. The two first limiting pieces 321 of each first pocket 32 ​​are respectively fitted with two second raceways 41 with clearance. The two second limiting pieces 331 of each second pocket 33 are respectively fitted with two first raceways 4 with clearance.

[0018] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope. All such changes and modifications fall within the scope of the present invention as claimed, which is defined by the appended claims and their equivalents.

Claims

1. A composite bearing, characterized in that: The device includes an inner ring, an outer ring, a cylindrical roller assembly, and a cage for housing the cylindrical roller assembly. The outer peripheral wall of the inner ring and the inner peripheral wall of the outer ring each have a first raceway and a second raceway. The first and second raceways on the inner ring are perpendicularly connected to form an inner raceway, and the first and second raceways on the outer ring are perpendicularly connected to form an outer raceway. The cylindrical roller assembly is movably disposed between the outer and inner raceways. The cylindrical roller assembly includes several cylindrical rollers, which are divided into several radially loaded rollers and several axially loaded rollers. The radially loaded rollers and the axially loaded rollers are staggered and arranged at 90° intervals. Each radially loaded roller is in contact with two first raceways, and the axis of the radially loaded roller is parallel to the axis of the inner ring. Each axially loaded roller is in contact with two second raceways, and the axis of the axially loaded roller is perpendicular to the axis of the inner ring.

2. A combined bearing according to claim 1, characterized in that: The diameter of the cylindrical roller is set to be greater than the length of the cylindrical roller. The formula for calculating the diameter of the cylindrical roller is Dw=ak*Lw, where Lw is the length of the roller and ak is a coefficient with a range of 1.2-1.

5.

3. A combined bearing according to claim 1, characterized in that: The cage is composed of several beams, with a common pocket formed between adjacent beams. The common pockets are divided into several first pockets for accommodating radially loaded rollers and several second pockets for accommodating axially loaded rollers. The first pockets and the second pockets are arranged alternately. The inner wall contour of each first pocket and each second pocket is adapted to the outer circular surface of its corresponding cylindrical roller. The radial cross-section of the first pocket and the second pocket is rectangular.

4. A combined bearing according to claim 3, characterized in that: Two first limiting plates are provided at each of the first pockets, and each first limiting plate is integrally connected to the adjacent beam. Two second limiting plates are provided at each of the second pockets, and each second limiting plate is integrally connected to the adjacent beam. The first limiting plates are perpendicular to the axis of the radially loaded roller, and the second limiting plates are perpendicular to the axis of the axially loaded roller.

5. A combined bearing according to claim 4, characterized in that: The two first limiting pieces of each of the first pockets are respectively configured to cooperate with the two second raceways.

6. A combined bearing according to claim 4, characterized in that: The two second limiting pieces of each second pocket are respectively configured to cooperate with the two first raceway gaps.

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