A rotary table assembly and machine tool

Abstract

This invention discloses a rotary table assembly and machine tool, belonging to the field of machine tool technology. It includes a support body with a vertically penetrating central hole at its center. A central spindle is disposed within the central hole, and a first bearing is fitted onto the central spindle located within the central hole. A worktable, connected to the upper end of the central spindle, is positioned above the support body. A second bearing is positioned between the worktable's base and the support body. The lower end of the central spindle extends away from the worktable and is connected to the output shaft of a motor via a coupling. A mounting sleeve, fitted onto the extended section of the central spindle, is located at the lower end of the support body. An mounting cavity is formed between the inner wall of the mounting sleeve and the central spindle, and a third bearing is disposed within the mounting cavity. A first elastic element is positioned between the bearing seat and the inner wall of the mounting sleeve. This invention can meet the requirements of high-precision grinding and improves the overall precision level of the machine tool. It has the advantages of high stability and maintenance-free operation.

Description

Technical Field

[0001] This invention belongs to the field of machine tool technology, and particularly relates to a rotary table assembly and a machine tool. Background Technology

[0002] In machine tools, the worktable that holds the workpiece can not only move linearly forward, backward, left, and right, but also rotate on a plane, thus enabling the processing of multiple surfaces of the raw material. It is also known as a rotary worktable.

[0003] Key functional components play a crucial role in improving the overall performance of a machine tool. The rotary table is a vital component in a grinding machine, where the user's workpiece is placed for grinding. Its quality directly determines the overall grinding performance of the machine tool. For machining large and heavy components, the rotary table needs to have a strong load-bearing capacity. However, existing rotary table structures using oil film-based high-strength lubrication cannot meet heavy-load requirements. Simultaneously, to meet machining requirements, grinding accuracy and efficiency need to be improved, which necessitates a small cumulative error and high rotational speed on the rotary table. Therefore, to meet the demands of high precision, high speed, and heavy-load operation, the design requirements for the rotary table are set as follows: a table surface area of ​​630mm, a rotational speed of 100r / min, and a load-bearing capacity of over 200kg. To meet these technical requirements, a rotary table assembly and machine tool are urgently needed. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a rotary table assembly and machine tool that can meet the requirements of high-precision grinding and improve the overall accuracy of the machine tool. It also features high stability and requires no maintenance.

[0005] The present invention is implemented as follows: On one hand, this application provides a rotary table assembly, including a support body, a central hole vertically penetrating the center of the support body, a central spindle disposed in the central hole, and a first bearing for bearing radial loads sleeved on the central spindle located in the central hole.

[0006] A worktable is provided above the support body and connected to the upper end of the central spindle. A second bearing for bearing the combined axial and radial loads is provided between the chassis of the worktable and the support body. The lower end of the central spindle extends away from the worktable and is connected to the output shaft of the motor through a coupling. The worktable rotates around the axis of the central spindle under the drive of the motor.

[0007] The lower end of the support body is provided with a mounting sleeve that is fitted onto the extended section of the central spindle. An mounting cavity is formed between the inner wall of the mounting sleeve and the central spindle. A third bearing for bearing axial load is provided in the mounting cavity. A first elastic element is provided between the seat ring of the third bearing and the inner wall of the mounting sleeve. Under the preload of the third bearing and the elastic element, the second bearing forms a closed rolling guide for supporting the rotation of the worktable.

[0008] Furthermore, the support body is connected to the slide plate via an arc guide rail, allowing the support body to swing along the arc guide rail. The support body and the slide plate are fixed together by fasteners, and an angle scale for displaying the swing angle of the support body is provided on the surface of the support body relative to the position of the fasteners.

[0009] The lower end of the support body is provided with a fan-shaped rack parallel to the arc guide rail. A drive shaft is provided below the fan-shaped rack. A gear that meshes with the fan-shaped rack is provided at the end of the drive shaft relative to the fan-shaped rack. A bevel gear set is provided at the end of the drive shaft away from the gear. The driving bevel gear of the bevel gear set is provided on the handle shaft. The drive end of the handle shaft extends to the front of the slide plate.

[0010] Furthermore, a fourth bearing is provided on the lower end face of the worktable located inside the second bearing. The fourth bearing cooperates with the rolling elements inside the second bearing to form auxiliary support for the rolling elements. The fourth bearing ensures the concentricity of the rolling elements inside the second bearing, prevents the rolling elements from dislodging from the raceway due to excessive rotational speed, and ensures the accuracy of the worktable.

[0011] Furthermore, a connecting sleeve is provided between the mounting sleeve and the motor. The connecting sleeve is fitted at the connection between the central spindle and the motor output shaft. A fifth bearing is provided between the half coupling on the motor output shaft side and the inner wall of the connecting sleeve, which can effectively ensure the coaxial accuracy of the rotation of the motor output shaft and the central spindle.

[0012] Furthermore, the outer edge of the worktable is provided with a first waterproof outer ring, and a first waterproof inner ring is provided on the support body relative to the first waterproof outer ring. The upper end of the first waterproof inner ring extends upward into the first waterproof outer ring. The first waterproof outer ring and the first waterproof inner ring are staggered to form a first waterproof channel. A first water storage tank is provided in the support body located outside the first waterproof inner ring. The grinding fluid in the first water storage tank flows back to the grinding area through a first return water path.

[0013] Furthermore, a second waterproof outer ring is provided on the lower end face of the worktable located outside the first bearing, and a second waterproof inner ring is provided on the support body relative to the second waterproof outer ring. The upper end of the second waterproof inner ring extends upward into the second waterproof outer ring. The second waterproof outer ring and the second waterproof inner ring are staggered to form a second waterproof channel. A second water storage tank is provided in the support body located outside the second waterproof inner ring. The grinding fluid in the second water storage tank flows back to the grinding area through the second return water path.

[0014] Furthermore, a through hole is provided at the center of the chassis of the worktable, and a slip ring is provided in the connecting sleeve at the end of the central spindle. A connecting channel is provided in the central spindle to connect the through hole and the slip ring. The suction cup in the worktable is connected to the slip ring through the connecting channel.

[0015] Furthermore, the worktable is a negative pressure worktable, the slip ring is a fluid slip ring, and the vacuum chuck in the negative pressure worktable is connected to the fluid slip ring through a connecting channel, and transmits gas fluid so that the connecting channel forms a vacuum channel; or, the worktable is an electromagnetic worktable, the slip ring is an electric slip ring, and the electromagnetic chuck in the electromagnetic worktable is electrically connected to the electric slip ring through a connecting channel, so that the connecting channel forms a circuit channel.

[0016] Furthermore, the coupling includes two half-couplings respectively disposed at the lower end of the central spindle and the motor output shaft. Torque is transmitted between the two half-couplings via a connecting member. The half-coupling located on the central spindle side has a mounting hole for installing the connecting member, and a second elastic element for adjusting the eccentricity of the central spindle is disposed within the mounting hole. Because the high-speed rotation of the motor generates vibration, any vibration source will eventually be transmitted to the worktable surface, affecting the grinding accuracy of the workpiece. Furthermore, due to errors in the accuracy and alignment of the central spindle, eccentricity problems are prone to occur. The second elastic element can absorb motor vibration and eccentricity, ensuring the grinding accuracy of the workpiece.

[0017] This application also provides a machine tool, which is provided with the rotary table assembly described above.

[0018] The advantages and technical effects of this invention are as follows: By adopting the above technical solution, it meets the requirements of high-precision grinding, achieving a worktable flatness of 0.002mm, a worktable end face runout of 0.0015mm, and a center hole positioning accuracy of 0.005mm. It also improves the overall precision level of the machine tool. The bearing assembly prevents radial runout and axial movement, ensuring precision while maintaining high accuracy at a low cost. It also features high stability and requires no maintenance.

[0019] To meet the high precision requirements of the worktable, it is necessary to restrict the radial and axial degrees of freedom. The first bearing uses a double-row radial cylindrical roller bearing with tapered bore to restrict the radial degree of freedom. The rolling elements are cylindrical, which has a larger bearing contact area than a cylindrical object, resulting in strong load-bearing capacity and rigidity. Since the worktable surface is 630mm and the overall size is relatively large, the use of a double-row bearing can provide sufficient rigidity for the whole.

[0020] The second bearing uses a thrust cylindrical roller bearing, and the third bearing uses a one-way thrust ball bearing. Axial freedom is restricted through these two bearings. The third bearing, using a one-way thrust ball bearing, can meet the heavy-load requirements of machining large and heavy components, improving compressive strength. The second bearing, using a thrust cylindrical roller bearing, improves rotational stability. Regardless of the weight of the workpiece being machined, good contact between the worktable and the support body is ensured, and the operating conditions are all within a reasonable range, meeting high-precision requirements. Through the reasonable placement and combination of these bearings, the design requirements are met. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure provided by the present invention;

[0022] Figure 2 This is a magnified view of part A provided in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the installation of the fan-shaped rack, drive shaft, gear, bevel gear set and handle shaft provided in the embodiments of the present invention;

[0024] Figure 4 This is a diagram of the fastener and angle scale installation structure provided in an embodiment of the present invention.

[0025] In the diagram: 1. Support body; 2. Central spindle; 3. First bearing; 4. Worktable; 5. Second bearing; 6. Coupling; 7. Motor; 8. Mounting sleeve; 9. Third bearing; 10. First elastic element; 11. Fourth bearing; 12. Connecting sleeve; 13. Fifth bearing; 14. First waterproof outer ring; 15. First waterproof inner ring; 16. First water storage tank; 17. Second waterproof outer ring; 18. Second waterproof inner ring; 19. Second water storage tank; 20. Through hole; 21. Slip ring; 22. Connecting channel; 23. Connecting piece; 24. Mounting hole; 25. Second elastic element; 26. Sector rack; 27. Drive shaft; 28. Gear; 29. ​​Bevel gear set; 30. Handle shaft; 31. Fastener; 32. Angle scale. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] It should be noted that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and 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. Therefore, they should not be construed as limiting the present invention.

[0028] Example 1

[0029] like Figure 1 As shown, this embodiment provides a rotary table 4 assembly, including a support body 1. Specifically, the support body 1 has an arc-shaped structure, and a central hole is vertically penetrating the center of the support body 1. A central spindle 2 is disposed in the central hole, and a first bearing 3 for bearing radial load is sleeved on the central spindle 2 located in the central hole. The first bearing 3 ensures the radial accuracy of the central spindle 2. Specifically, the first bearing 3 is a P2-grade tapered roller bearing with a double-row radial cylindrical roller bearing. The tapered roller bearing has a tapered inner ring raceway and an outer ring raceway, with tapered rollers arranged between the two. The projection lines of all the tapered surfaces converge at the same point on the bearing axis. This design makes the tapered roller bearing particularly suitable for bearing radial loads. Tapered roller bearings are usually separable, that is, the tapered inner ring assembly, which consists of an inner ring with rollers and a cage assembly, can be installed separately from the tapered outer ring.

[0030] A worktable 4, connected to the upper end of the central spindle 2, is positioned above the support body 1. A second bearing 5, specifically a P2-class thrust cylindrical roller bearing, is installed between the chassis of the worktable 4 and the support body 1 to withstand combined axial and radial loads. The lower end of the central spindle 2 extends away from the worktable 4 and is connected to the output shaft of the motor 7 via a coupling 6. This direct connection between the motor 7 and the central spindle 2 maximizes the transmission of motor torque. The worktable 4 rotates around the axis of the central spindle 2 under the drive of the motor 7. Specifically, the motor 7 is a three-phase geared motor. To meet the requirement of a maximum speed of 100 r / min for the horizontal spindle rotary table surface grinder, a high-efficiency motor 7 with a reduction ratio of 1:15 is used to smoothly rotate the worktable 4.

[0031] The lower end of the support body 1 is provided with a mounting sleeve 8 that is fitted onto the extended section of the central spindle 2. An mounting cavity is formed between the inner wall of the mounting sleeve 8 and the central spindle 2. A third bearing 9, designed to withstand axial loads, is installed within the mounting cavity. Specifically, the third bearing 9 is a P2-class single-direction thrust ball bearing. A first elastic element 10 is provided between the seat ring of the third bearing 9 and the inner wall of the mounting sleeve 8. Preferably, the first elastic element 10 is a disc spring. Under the preload of the third bearing 9 and the elastic element, the second bearing 5 forms a closed rolling guide rail for supporting the rotation of the worktable 4. The second bearing 5, the third bearing 9, and the elastic element eliminate axial clearance and movement. The mounting surfaces of the second and third bearings have extremely strict requirements: the parallelism of the bearing mounting surfaces is 0.005 mm, and the perpendicularity to the center hole is 0.002 mm. The required flat surfaces must be manually scraped and prepared using a special grinding tool.

[0032] Thrust cylindrical roller bearings are separable bearings, generally consisting of washer-shaped raceway rings and a cylindrical roller cage assembly. The cylindrical rollers are machined with convex surfaces, resulting in uniform pressure distribution between the rollers and raceway surfaces. They can withstand unidirectional axial loads, possessing high axial load capacity and strong axial rigidity. Unidirectional thrust ball bearings can withstand unidirectional axial loads and provide unidirectional axial positioning, but cannot withstand any radial loads. The combined use of the second bearing (5) and the third bearing (9) plays a decisive role in the rotational accuracy and load-bearing capacity of the entire rotary table assembly (4).

[0033] Example 2

[0034] like Figure 3 and Figure 4 As shown, unlike Embodiment 1, in this embodiment, the support body 1 is connected to the slide plate via an arc guide rail, allowing the support body 1 to swing along the arc guide rail. The support body 1 and the slide plate are fixed together by fasteners 31, specifically T-nuts. An angle scale 32 for displaying the swing angle of the support body 1 is provided on the surface of the support body 1 at the position of the fastener 31. The worktable 4 has an tilting auxiliary function to meet the needs of external and internal cone machining.

[0035] The lower end of the support body 1 is provided with a fan-shaped rack 26 parallel to the arc guide rail. A drive shaft 27 is provided below the fan-shaped rack 26. A gear 28 that meshes with the fan-shaped rack 26 is provided at the end of the drive shaft 27 relative to the fan-shaped rack 26. A bevel gear set 29 is provided at the end of the drive shaft 27 away from the gear 28. The driving bevel gear 28 of the bevel gear set 29 is provided on the handle shaft 30. The driving end of the handle shaft 30 extends to the front of the slide plate.

[0036] Fastener 31 can firmly fix the worktable 4 to the slide, giving the worktable 4 high rigidity and strength, and enabling it to withstand large grinding loads.

[0037] When the worktable tilts on all four sides, first loosen the two T-nuts, and then use the worktable wrench to crank the square-hole handle shaft 30 on the front left side of the slide. This drives the transmission shaft 27 to rotate via a pair of bevel gears 28. The gears 28 on the transmission shaft 27 mesh with the sector rack 26, causing the support body 1 to swing along the arc-shaped guide surface to the required angle, with a maximum of ±6°. The angle after swinging can be read from the front angle scale 32. Then tighten the two T-nuts to clamp the support body 1 and the arc-shaped guide surface of the slide, fixing the angle.

[0038] Example 3

[0039] Unlike Embodiments 1 and 2, in this embodiment, a fourth bearing 11 is provided on the lower end face of the worktable 4 located inside the second bearing 5. Specifically, the fourth bearing 11 is a radial ball bearing. A bolt is provided on the lower end face of the worktable 4 located inside the second bearing 5, and a mounting sleeve is fitted onto the bolt shank located outside the worktable 4. The mounting sleeve has a mounting groove, and the fourth bearing 11 is disposed within the mounting groove of the mounting sleeve. The fourth bearing 11 cooperates with the rolling elements inside the second bearing 5 to form auxiliary support for the rolling elements inside the second bearing 5.

[0040] Preferably, three fourth bearings 11 are provided, and the three fourth bearings 11 are evenly distributed along the circumference of the second bearing 5 on the lower end surface of the worktable 4 inside the second bearing 5.

[0041] The fourth bearing 11 ensures the concentricity of the rolling elements in the second bearing 5, prevents the rolling elements from detaching from the raceway due to excessive speed, and ensures the accuracy of the worktable 4.

[0042] Example 4

[0043] Unlike Embodiment 1, in this embodiment, a connecting sleeve 12 is provided between the mounting sleeve 8 and the motor 7. The connecting sleeve 12 is sleeved at the connection between the central spindle 2 and the output shaft of the motor 7. A fifth bearing 13 is provided between the half coupling on the output shaft side of the motor 7 and the inner wall of the connecting sleeve 12. Specifically, the fifth bearing 13 is a radial ball bearing, which can effectively ensure the coaxial accuracy of the rotation of the output shaft of the motor 7 and the central spindle 2.

[0044] Preferably, the connection position between the mounting sleeve 8 and the connecting sleeve 12 is provided with an adjusting pad, which can adjust the positional error between the mounting sleeve 8 and the connecting sleeve 12. The mounting sleeve 8 and the connecting sleeve 12 are connected to each other by bolts.

[0045] During operation, the central spindle 2 is a vulnerable part that requires maintenance and repair. With the connection sleeve 12 and the mounting sleeve 8, the central spindle 2 can be repaired by disassembling and assembling the mounting sleeve 8 and the connection sleeve 12 separately, avoiding complete disassembly and facilitating maintenance and installation.

[0046] Example 5

[0047] Unlike Embodiment 1, in this embodiment, the outer edge of the worktable 4 is provided with a first waterproof outer ring 14, and a first waterproof inner ring 15 is provided on the support body 1 relative to the first waterproof outer ring 14. The upper end of the first waterproof inner ring 15 extends upward into the first waterproof outer ring 14. The first waterproof outer ring 14 and the first waterproof inner ring 15 are staggered to form a first waterproof channel. A first water storage tank 16 is provided in the support body 1 located outside the first waterproof inner ring 15. The grinding fluid in the first water storage tank 16 flows back to the grinding area through a first return water path. To prevent the grinding fluid from entering the outer ring of the worktable 4, the first waterproof channel reduces corrosion and wear on the outer ring of the worktable 4, thereby improving the service life of the worktable 4. Furthermore, the first return water path allows the entering grinding fluid to flow back to the grinding area for recycling.

[0048] Example 6

[0049] Unlike Embodiment 1, in this embodiment, a second waterproof outer ring 17 is provided on the lower end face of the worktable 4 located outside the first bearing 3. A second waterproof inner ring 18 is provided on the support body 1 opposite to the second waterproof outer ring 17. The upper end of the second waterproof inner ring 18 extends upward into the second waterproof outer ring 17. The second waterproof outer ring 17 and the second waterproof inner ring 18 are staggered to form a second waterproof channel. A second water storage tank 19 is provided in the support body 1 located outside the second waterproof inner ring 18. The grinding fluid in the second water storage tank 19 flows back to the grinding area through a second return water path. To prevent the grinding fluid from entering the bearing, the second waterproof channel reduces bearing corrosion and wear, improves bearing service life and the rotational accuracy of the worktable 4. Furthermore, the second return water path allows the entering grinding fluid to flow back to the grinding area for recycling.

[0050] Example 7

[0051] Unlike Embodiment 1, in this embodiment, the workbench 4 has a through hole 20 at the center of its chassis, a slip ring 21 is provided in the connecting sleeve 12 at the end of the central spindle 2, and a connecting channel 22 is provided in the central spindle 2 to connect the through hole 20 and the slip ring 21. The suction cup in the workbench 4 is connected to the slip ring 21 through the connecting channel 22.

[0052] The workbench 4 has an M20 screw hole in the center for lifting. When lifting, unscrew the screw plug and tighten it after lifting to prevent water and grinding debris from entering.

[0053] The accuracy of worktable 4 has a significant impact on the accuracy of the workpiece being machined. The flatness of the table surface must be maintained and checked frequently to be 0.003mm. When out-of-tolerance errors are found, timely correction is necessary, requiring a large amount of coolant during correction.

[0054] Example 8

[0055] Unlike Embodiment 7, in this embodiment, the worktable 4 is a negative pressure worktable 4, and the slip ring 21 is a fluid slip ring. The vacuum chuck inside the negative pressure worktable 4 is connected to the fluid slip ring through the connecting channel 22, and transmits gas fluid to form a vacuum channel in the connecting channel 22. It can also grind special non-magnetic workpieces such as stainless steel and ceramics to obtain higher parallelism and surface finish.

[0056] Example 9

[0057] Unlike Embodiment 7, in this embodiment, the worktable 4 is an electromagnetic worktable 4, and the slip ring 21 is an electric slip ring. The electromagnetic chuck inside the electromagnetic worktable 4 is electrically connected to the electric slip ring through a connecting channel 22, forming a circuit channel. The magnetic poles of the electromagnetic worktable 4 are distributed in concentric circles, which can meet the needs of most enterprise users on the market. It is especially widely used in the bearing industry for grinding various specifications of paired bearings with excellent consistency. The electromagnetic chuck uses a DC voltage of 110V, a DC resistance of 110Ω, a current of 1.25A, and a power of 0.14Kw. The electromagnetic table is equipped with an electromagnetic coil, and the DC power supply is introduced through brushes and the electric slip ring. The magnetic force of the electromagnetic chuck is ≥80N / cm2, which can meet the grinding requirements of flat and conical surfaces of castings, steel parts, and alloy parts. When the workpiece is placed on the surface of the electromagnetic worktable 4, it should cross as many opposite magnetic poles as possible, at least one pair of opposite magnetic poles. Its uniform magnetism not only firmly fixes the workpiece on the table during grinding, but also ensures that every part of the workpiece surface is in uniform contact with the grinding wheel, thus improving grinding accuracy.

[0058] Example 10

[0059] like Figure 2 As shown, unlike Embodiment 1, the coupling 6 in this embodiment includes two half couplings respectively disposed at the lower end of the central spindle 2 and the output shaft of the motor 7. The torque is transmitted between the two half couplings through a connecting member 23. Specifically, the connecting member 23 is a pin. The two half couplings can be connected to the lower end of the central spindle 2 and the output shaft of the motor 7 by a key or a pin.

[0060] Preferably, there are three connecting members 23, and the three connecting members 23 are arranged on the same side of the axis of the coupling 6.

[0061] A mounting hole 24 for mounting the connector 23 is provided in the half-coupling located on the side of the central spindle 2. A second elastic element 25 for adjusting the eccentricity of the central spindle 2 is provided within the mounting hole 24. Placing the second elastic element in the half-coupling on the side of the central spindle 2 is advantageous because the motor 7 side is the input end and has high rigidity. If the second elastic element were placed in the half-coupling on the motor 7 side, the vibration absorption effect would be poor. Therefore, after the force is transmitted through the connector, placing the second elastic element 25 in the half-coupling on the side of the central spindle 2 can more effectively absorb the vibration. Specifically, the second elastic element 25 is a rubber pad. Since the motor 7 generates vibration when rotating at high speed, any vibration source will eventually be transmitted to the table surface of the worktable 4, affecting the grinding accuracy of the workpiece. Furthermore, due to errors in the accuracy and installation alignment of the central spindle 2, eccentricity problems are prone to occur. The second elastic element 25 can absorb the vibration of the motor 7 and the eccentricity, ensuring the grinding accuracy of the workpiece.

[0062] Example 11

[0063] This embodiment provides a machine tool equipped with the rotary worktable 4 assembly described above. Specifically, the machine tool is a grinding machine.

[0064] By adopting the above technical solution, the high-precision grinding requirements are met, resulting in a table surface flatness of 0.002mm, a table end face runout of 0.0015mm, and a center hole positioning accuracy of 0.005mm. This also improves the overall precision level of the machine tool. Radial runout and axial movement are prevented through bearing assemblies, ensuring high precision at a low cost. It also boasts high stability and requires no maintenance.

[0065] To meet the high precision requirements of the worktable, it is necessary to restrict the radial and axial degrees of freedom. The first bearing uses a double-row radial cylindrical roller bearing with tapered bore to restrict the radial degree of freedom. The rolling elements are cylindrical, which has a larger bearing contact area than a cylindrical object, resulting in strong load-bearing capacity and rigidity. Since the worktable surface is 630mm and the overall size is relatively large, the use of a double-row bearing can provide sufficient rigidity for the whole.

[0066] The second bearing uses a thrust cylindrical roller bearing, and the third bearing uses a one-way thrust ball bearing. Axial freedom is restricted through these two bearings. The third bearing, using a one-way thrust ball bearing, can meet the heavy-load requirements of machining large and heavy components, improving compressive strength. The second bearing, using a thrust cylindrical roller bearing, improves rotational stability. Regardless of the weight of the workpiece being machined, good contact between the worktable and the support body is ensured, and the operating conditions are all within a reasonable range, meeting high-precision requirements. Through the reasonable placement and combination of these bearings, the design requirements are met.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rotary table assembly, characterized in that, It includes a support body, a central hole that runs vertically through the center of the support body, a central spindle that is provided in the central hole, and a first bearing for bearing radial loads is sleeved on the central spindle located in the central hole. A worktable is provided above the support body and connected to the upper end of the central spindle. A second bearing for bearing the combined axial and radial loads is provided between the chassis of the worktable and the support body. The lower end of the central spindle extends away from the worktable and is connected to the output shaft of the motor through a coupling. The worktable rotates around the axis of the central spindle under the drive of the motor. The lower end of the support body is provided with a mounting sleeve that is fitted onto the extended section of the central spindle. An mounting cavity is formed between the inner wall of the mounting sleeve and the central spindle. A third bearing for bearing axial load is provided in the mounting cavity. A first elastic element is provided between the seat ring of the third bearing and the inner wall of the mounting sleeve. Under the preload of the third bearing and the elastic element, the second bearing forms a closed rolling guide for supporting the rotation of the worktable to eliminate axial clearance and movement. A fourth bearing is provided on the lower end face of the workbench located inside the second bearing. The fourth bearing cooperates with the rolling elements inside the second bearing to form auxiliary support for the rolling elements inside the second bearing.

2. The rotary table assembly according to claim 1, characterized in that, The support body is connected to the slide plate via an arc guide rail, allowing the support body to swing along the arc guide rail. The support body and the slide plate are fixed together by fasteners. An angle scale for displaying the swing angle of the support body is provided on the surface of the support body relative to the position of the fasteners. The lower end of the support body is provided with a fan-shaped rack parallel to the arc guide rail. A drive shaft is provided below the fan-shaped rack. A gear that meshes with the fan-shaped rack is provided at the end of the drive shaft relative to the fan-shaped rack. A bevel gear set is provided at the end of the drive shaft away from the gear. The driving bevel gear of the bevel gear set is provided on the handle shaft. The drive end of the handle shaft extends to the front of the slide plate.

3. The rotary table assembly according to claim 1, characterized in that, A connecting sleeve is provided between the mounting sleeve and the motor. The connecting sleeve is fitted at the connection between the central spindle and the motor output shaft. A fifth bearing is provided between the half coupling on the motor output shaft side and the inner wall of the connecting sleeve.

4. The rotary table assembly according to claim 1, characterized in that, The worktable is provided with a first waterproof outer ring on its outer edge, and a first waterproof inner ring is provided on the support body relative to the first waterproof outer ring. The upper end of the first waterproof inner ring extends upward into the first waterproof outer ring. The first waterproof outer ring and the first waterproof inner ring are staggered to form a first waterproof channel. A first water storage tank is provided in the support body located outside the first waterproof inner ring. The grinding fluid in the first water storage tank flows back to the grinding area through a first return water path.

5. The rotary table assembly according to claim 1, characterized in that, A second waterproof outer ring is provided on the lower end face of the worktable located outside the first bearing. A second waterproof inner ring is provided on the support body relative to the second waterproof outer ring. The upper end of the second waterproof inner ring extends upward into the second waterproof outer ring. The second waterproof outer ring and the second waterproof inner ring are staggered to form a second waterproof channel. A second water storage tank is provided in the support body located outside the second waterproof inner ring. The grinding fluid in the second water storage tank flows back to the grinding area through the second return water path.

6. The rotary table assembly according to claim 1, characterized in that, The workbench has a through hole at the center of its chassis, and a slip ring is provided in the connecting sleeve at the end of the central spindle. The central spindle has a connecting channel that connects the through hole and the slip ring. The suction cup in the workbench is connected to the slip ring through the connecting channel.

7. The rotary table assembly according to claim 6, characterized in that, The worktable is a negative pressure worktable, the slip ring is a fluid slip ring, and the vacuum suction cup in the negative pressure worktable is connected to the fluid slip ring through a connecting channel, and transmits gas fluid so that the connecting channel forms a vacuum channel. Alternatively, the workbench is an electromagnetic workbench, the slip ring is an electric slip ring, and the electromagnetic chuck in the electromagnetic workbench is electrically connected to the electric slip ring through a connecting channel, so that the connecting channel forms a circuit channel.

8. The rotary table assembly according to claim 1, characterized in that, The coupling includes two half-couplings respectively disposed at the lower end of the central spindle and the motor output shaft. Torque is transmitted between the two half-couplings through a connecting member. The half-coupling located on the side of the central spindle is provided with a mounting hole for installing the connecting member. A second elastic element for adjusting the eccentricity of the central spindle is provided in the mounting hole.

9. A machine tool, characterized in that, The machine tool is equipped with a rotary table assembly as described in any one of claims 1 to 8.

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