Bearing structure for machine tool rotary table

Abstract

The application discloses a three-row cylindrical roller machine tool rotary table bearing structure, which comprises an inner ring (divided into a first inner ring and a second inner ring), an outer ring and three rows of cylindrical rollers (axial rollers and radial rollers). The outer ring raceway is provided with steps on both sides, so that the size of the rolling body is increased, the load is increased, and a radial stop edge is formed to prevent movement; the rolling body is designed with a spherical base surface, point contact is formed by matching the inclined stop edge, and friction is reduced; the axial retainer is of a segmented structure, is distributed in multiple segments in a circumferential direction, and is provided with a gap to prevent temperature rise and locking; the inner side surface is lengthened to adapt to the step structure; the retainer is provided with a "wavy" circular arc groove to store grease and improve lubricating effect; and the radial retainer is of a long strip-shaped cylindrical pocket structure, the rolling body is fixed through locking on both sides, and the radial retainer can be purchased in batches and is adapted to products of different sizes by cutting and bending. The structure improves bearing rigidity, load capacity and service life, and reduces friction torque and mold cost.

Description

Technical Field

[0001] This invention relates to the field of machine tool equipment technology, and more specifically to a machine tool rotary table bearing structure. Background Technology

[0002] Machine tool rotary table bearings are core components of industrial mother machines. In the industry, this product was previously reliant on imports. However, domestic companies have achieved breakthroughs after years of research, and some products have replaced imports. Currently, the industry is focusing on upgrading to "high speed, precision, and intelligence," adapting to high-end demands such as five-axis CNC machine tools, further increasing the requirements for rotary table bearings. Currently, the load-bearing capacity, overall rigidity, and friction torque requirements of these products need further improvement.

[0003] Currently, there is a utility model patent with patent number 201922362319.X entitled "A High-Speed ​​Precision Turntable Bearing", which discloses that the bearing achieves axial and radial load bearing by setting axial load bearing rollers and radial load bearing rollers. However, the cage structure of the above bearing is a conventional structure. Therefore, the bearing's load bearing capacity, overall stiffness, and friction torque still have the above-mentioned deficiencies. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a machine tool rotary table bearing structure that improves the bearing's load-bearing capacity, overall rigidity, and reduces frictional torque by optimizing the cage structure design.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a machine tool rotary table bearing structure, comprising a bearing ring, a bearing base, a bearing cap, a plurality of axial rollers and radial rollers. The inner ring wall of the bearing base has a raceway notch. The bearing cap is fixed to the bearing base, covering one side of the raceway notch to form a raceway groove. The groove wall of the raceway groove has an outer ring axial raceway, and the bottom of the raceway groove has an outer ring radial raceway. The inner side and two end faces of the bearing ring have inner ring radial raceways and inner ring axial raceways. The axial rollers are located within the outer ring axial raceway. Between the inner ring axial raceway and the outer ring radial raceway, the radial rollers are located between the outer ring radial raceway and the inner ring radial raceway. An axial cage is fitted on the axial rollers, and a radial cage is fitted on the radial rollers. The radial cage is long and has several radial pockets. Two radial locking blocks are provided on the wall of the radial pockets. The radial locking blocks face the inside of the radial pockets to form locking points for locking the radial rollers. The radial cage is made of flexible material, and after being bent end to end, it is fitted onto the bearing ring. The radial rollers are positioned one by one in the radial pockets.

[0006] As a further improvement of the present invention, auxiliary grooves are provided on the radial retainer at the positions of two adjacent radial pockets to assist the radial retainer in bending with its ends connected.

[0007] As a further improvement of the present invention, the axial cage is formed by a plurality of arc-shaped cage units.

[0008] As a further improvement of the present invention, the cage unit includes an outer curved plate, an inner curved plate and several connecting ribs, the two ends of the several connecting ribs being fixed to the outer curved plate and the inner curved plate respectively, so as to connect and fix the outer curved plate and the inner curved plate, and an axial pocket is formed between two adjacent connecting ribs for accommodating axial rollers.

[0009] As a further improvement of the present invention, wedge blocks are provided on the two opposite hole walls in the circumferential direction of the axial pocket, and the wedge surface of the wedge blocks contacts the side surface of the axial roller. Semi-cylindrical blocks are provided on the two opposite hole walls in the radial direction, and the semi-cylindrical blocks contact the end face of the axial roller. An axial locking block inclined towards the pocket is provided on the connecting rib. The axial locking block, wedge blocks and semi-cylindrical blocks are combined to form a rolling space that locks the axial roller.

[0010] As a further improvement of the present invention, the inner ring axial raceway forms a stepped structure on the end face of the bearing ring, and the width of the inner curved plate is greater than the width of the inner curved plate, so that when the axial cage is placed on the bearing ring, it adapts to the stepped structure of the bearing ring.

[0011] As a further improvement of the present invention, a support block is provided on one side of the connecting rib relative to the inner curved plate. The support block has a semi-cylindrical structure, with one end connected to the inner curved plate and the other end having a hemispherical head structure. When the axial retainer is placed on the bearing ring, the curved surface of the support block abuts against the bearing ring.

[0012] As a further improvement of the present invention, a number of arc-shaped grooves are provided on the two end edges of the outer curved plate, so that the side of the outer curved plate is wavy in the radial direction. A number of arc-shaped grooves are provided on the inner and outer surfaces of the inner curved plate, so that the side of the inner curved plate is wavy in the axial direction.

[0013] The beneficial effects of this invention are as follows: The adoption of a three-row cylindrical roller structure (axial rollers bear axial loads and overturning moments, radial rollers bear radial loads) significantly improves the overall bearing capacity; the stepped design of the outer ring raceway increases the size of the rolling elements and forms radial flanges, effectively improving radial stiffness and preventing movement; the point contact between the spherical base of the rolling elements and the inclined flanges reduces sliding friction and lowers running torque; the segmented structure of the axial cage adapts to large-size bearings, reducing mold costs and reserving a temperature rise clearance to prevent jamming; the "wavy" arc grooves of the cage store grease, improving lubrication and extending service life; the elongated design of the radial cage supports bulk purchasing, and by cutting and bending, it can be adapted to products of different sizes, reducing production costs. The inner ring clearance elimination design puts the rolling elements in a pre-compression state, further improving overall stiffness and reducing noise. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the machine tool rotary table bearing structure of the present invention; Figure 2 for Figure 1 A cross-sectional view of one side of the middle section; Figure 3 This is a schematic diagram of the radial cage structure; Figure 4 This is a structural schematic diagram of the cage unit; Figure 5 This is a schematic diagram of the stepped structure. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the embodiments shown in the accompanying drawings.

[0016] Reference Figure 1 , Figure 2 , Figure 3 As shown, the machine tool rotary table bearing structure of this embodiment includes a bearing ring 1, a bearing base 2, a bearing cap 3, several axial rollers 4, and radial rollers 5. The inner ring wall of the bearing base 2 has a raceway notch. The bearing cap 3 is fixed to the bearing base 2, covering one side of the raceway notch to form a raceway groove. The groove wall of the raceway groove has an outer ring axial raceway 22, and the bottom of the raceway groove has an outer ring radial raceway 21. The inner side and two end faces of the bearing ring 1 have inner ring radial raceways 12 and inner ring axial raceways 11. The axial rollers 4 are located between the outer ring axial raceways 22 and the inner ring axial raceways 11, and the radial rollers 5... Roller 5 is positioned between the outer ring radial raceway 21 and the inner ring radial raceway 12. An axial retainer 6 is fitted onto the axial roller 4, and a radial retainer 7 is fitted onto the radial roller 5. The radial retainer 7 is elongated and has several radial pockets 71. Two parallel radial locking blocks 72 are provided on the wall of each radial pocket 71, forming locking points for locking the radial roller 5 towards the inside of the radial pocket 71. The radial retainer 7 is made of flexible material, bent end-to-end, and fitted onto the bearing ring 1. The radial rollers 5 are positioned one-to-one within the radial pockets 71. During machine operation, axial load and overturning moment are transmitted to the axial roller 4 through the inner ring axial raceway 11 of the bearing ring 1, and then distributed to the bearing base 2 via the outer ring axial raceway 22. Radial load is transmitted from the inner ring radial raceway 12 to the outer ring radial raceway 21 through the radial roller 5. The axial retainer 6 achieves multi-directional limiting of the axial roller 4 through the combination structure of wedge block 621, semi-cylindrical block 622 and axial locking block 623; the radial retainer 7 fixes the radial roller 5 through radial locking block 72, and the flexible material is used to achieve bending and forming, so that the radial retainer 7 can support batch purchase and adapt to products of different sizes by cutting and bending, thereby reducing production costs.

[0017] Reference Figure 3As shown, furthermore, auxiliary grooves 73 are provided on the radial cage 7 at the positions of two adjacent radial pockets 71 to assist in the bending of the radial cage 7 end to end. The auxiliary grooves 73 reduce bending resistance by reducing the material thickness, making the bending radius of the cage more accurate, avoiding material fatigue caused by bending stress, and extending service life.

[0018] Reference Figure 4 As shown, the axial cage 6 is further formed by several arc-shaped cage units 61. The modular design allows the axial cage 6 to be flexibly combined according to the number of rollers, reducing mold costs and facilitating partial replacement and maintenance.

[0019] Reference Figure 4 As shown, the cage unit 61 further includes an outer curved plate 611, an inner curved plate 612, and several connecting ribs 613. The two ends of the connecting ribs 613 are fixed to the outer curved plate 611 and the inner curved plate 612 respectively, thus connecting and fixing the outer curved plate 611 and the inner curved plate 612. An axial pocket 62 for accommodating the axial roller 4 is formed between adjacent connecting ribs 613. The frame structure improves the overall rigidity of the cage, and the uniform distribution of the connecting ribs 613 makes the stress distribution more balanced.

[0020] Furthermore, wedge-shaped blocks 621 are provided on both opposite bore walls of the axial pocket 62 in the circumferential direction of the axial retainer 6. The wedge surfaces of the wedge-shaped blocks 621 contact the side surfaces of the axial rollers 4. Semi-cylindrical blocks 622 are provided on both opposite bore walls in the radial direction. The semi-cylindrical blocks 622 contact the end faces of the axial rollers 4. An axial locking block 623 inclined towards the pocket 62 is provided on the connecting rib 613. The axial locking block 623, wedge-shaped blocks 621, and semi-cylindrical blocks 622 combine to form a rolling space that locks the axial rollers 4. The multi-directional limiting structure prevents the rollers from moving around, and the wedge-shaped surface design reduces the contact area, thereby reducing friction. At the same time, it leaves a large space between the axial rollers 4 and the axial pocket 62 for storing lubricating grease.

[0021] Reference Figure 5 As shown, furthermore, the inner ring axial raceway 11 forms a stepped structure on the end face of the bearing ring 1, and the width of the inner curved plate 612 is greater than the width of the outer curved plate 611, so that when the axial cage 6 is placed on the bearing ring 1, it fits the stepped structure of the bearing ring 1. The stepped fitting design enhances the fit between the cage and the bearing ring 1 and improves the axial positioning accuracy.

[0022] Furthermore, a support block 614 is provided on one side of the connecting rib 613 opposite to the inner curved plate 612. The support block 614 has a semi-cylindrical structure, with one end connected to the inner curved plate 612 and the other end having a hemispherical head structure. When the axial retainer 6 is placed on the bearing ring 1, the curved surface of the support block 614 abuts against the bearing ring 1. The hemispherical head support structure reduces contact friction and reduces resistance during bearing operation.

[0023] Furthermore, several arc-shaped grooves are formed on the two end edges of the outer curved plate 611, making the radial side of the outer curved plate 611 wavy. Similarly, several arc-shaped grooves are formed on the inner and outer surfaces of the inner curved plate 612, making the axial side of the inner curved plate 612 wavy. This wavy structure reduces weight while optimizing material stress distribution, improving the elastic deformation capacity of the cage, and also stores grease through the arc-shaped grooves, improving lubrication and extending service life.

[0024] In summary, this invention achieves high load-bearing capacity and rigidity through a three-row cylindrical roller structure design (axial roller 4 + radial roller 5) combined with preload technology to eliminate gaps in the bearing base 2; the stepped and inclined flange design of the bearing ring 1 enhances radial stiffness and reduces friction; the segmented axial cage 6 and the wave-shaped grease storage structure balance mold cost control and lubrication effect; the flexible, elongated radial cage 7 is adapted to multiple product sizes by being cut and bent, reducing production costs.

[0025] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A machine tool rotary table bearing structure, comprising a bearing ring (1), a bearing base (2), a bearing cap (3), a plurality of axial rollers (4) and radial rollers (5), wherein the inner ring wall of the bearing base (2) is provided with a raceway notch, the bearing cap (3) is fixed on the bearing base (2) and covers one side of the raceway notch to form a raceway groove, the groove wall of the raceway groove is provided with an outer ring axial raceway (22), the bottom of the raceway groove is provided with an outer ring radial raceway (21), the inner side surface and two end faces of the bearing ring (1) are provided with an inner ring radial raceway (12) and an inner ring axial raceway (11), the axial rollers (4) are located between the outer ring axial raceway (22) and the inner ring axial raceway (11), the radial rollers (5) are located between the outer ring radial raceway (21) and the inner ring radial raceway (12), an axial cage (6) is fitted on the axial rollers (4), and a radial cage (7) is fitted on the radial rollers (5), characterized in that: The radial retainer (7) is long and has several radial pockets (71) on it. Two radial locking blocks (72) are provided on the wall of the radial pocket (71). The radial locking blocks (72) form locking points for locking the radial rollers (5) on the inner side of the radial pocket (71). The radial retainer (7) is made of flexible material and is bent and fitted onto the bearing ring (1) after being connected end to end. The radial rollers (5) are located in the radial pockets (71) one by one.

2. The machine tool rotary table bearing structure according to claim 1, characterized in that: The radial retainer (7) has auxiliary grooves (73) at the positions of two adjacent radial pockets (71) to assist the radial retainer (7) in bending with its ends connected.

3. The machine tool rotary table bearing structure according to claim 2, characterized in that: The axial cage (6) is formed by several arc-shaped cage units (61).

4. The machine tool rotary table bearing structure according to claim 3, characterized in that: The cage unit (61) includes an outer curved plate (611), an inner curved plate (612), and several connecting ribs (613). The two ends of the several connecting ribs (613) are fixed to the outer curved plate (611) and the inner curved plate (612) respectively, so as to connect and fix the outer curved plate (611) and the inner curved plate (612). An axial pocket (62) for accommodating the axial roller (4) is formed between two adjacent connecting ribs (613).

5. The machine tool rotary table bearing structure according to claim 4, characterized in that: The axial pocket (62) has two opposing hole walls in the circumferential direction of the axial retainer (6) with wedge blocks (621) on each side. The wedge surface of the wedge block (621) contacts the side of the axial roller (4). The two opposing hole walls in the radial direction have semi-cylindrical blocks (622) on each side. The semi-cylindrical blocks (622) contact the end face of the axial roller (4). The connecting rib (613) has an axial locking block (623) that is inclined toward the pocket (62). The axial locking block (623), the wedge block (621) and the semi-cylindrical block (622) are combined to form a rolling space that locks the axial roller (4).

6. The machine tool rotary table bearing structure according to claim 5, characterized in that: The inner ring axial raceway (11) forms a stepped structure on the end face of the bearing ring (1). The width of the inner curved plate (612) is greater than the width of the inner curved plate (612), so that when the axial cage (6) is placed on the bearing ring (1), it fits the stepped structure of the bearing ring (1).

7. The machine tool rotary table bearing structure according to claim 6, characterized in that: The connecting rib (613) has a support block (614) on one side relative to the inner curved plate (612). The support block (614) is a semi-cylindrical structure, with one end connected to the inner curved plate (612) and the other end being a hemispherical head structure. When the axial retainer (6) is placed on the bearing ring (1), the curved surface of the support block (614) abuts against the bearing ring (1).

8. The machine tool rotary table bearing structure according to claim 7, characterized in that: The outer curved plate (611) has several arc-shaped grooves on its two end edges, so that the outer curved plate (611) has a wavy side in the radial direction. The inner curved plate (612) has several arc-shaped grooves on its inner and outer surfaces, so that the inner curved plate (612) has a wavy side in the axial direction.

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