Brake device structure with redundancy function and numerical control rotary table

Abstract

This invention discloses a braking device structure with redundant functions and a CNC rotary table, including a locking screw, a locking nut, a sealing piston cylinder, an upper washer, a spring, a lower washer, and a pressure block; the locking screw is fixed to the pressure plate by a threaded connection, the sealing piston cylinder is sleeved outside the locking screw, and the sealing piston cylinder is fixedly connected to the pressure plate by a thread; the locking nut is threaded to the sealing piston cylinder, and the lower washer, spring, and upper washer are sequentially mounted on the sealing piston cylinder. By rotating the locking nut to compress the spring, braking force is generated; this invention has three main features: 1) The braking devices all adopt a redundant structure design, with the braking force being borne by multiple parts simultaneously, resulting in long service life, reliable performance, and high safety; 2) The braking of the worktable is completed by multiple sets of braking devices, which have parallel characteristics in function, resulting in high reliability; 3) Long accuracy retention time.

Description

Technical Field

[0001] This invention relates to the field of CNC machine tools, and specifically to a braking device structure with redundant functions and a CNC rotary table. Background Technology

[0002] Foreign suppliers have begun to impose restrictions on my country in various aspects, including component supply, pricing, delivery time, and specifications, posing a risk of supply chain disruptions. Therefore, resolving the long-standing reliance on imports for key and core components, and the resulting vulnerability to foreign control, is a common challenge faced by equipment manufacturing enterprises.

[0003] A braking device structure with redundancy and a CNC rotary table are disclosed. The braking device structure and the CNC rotary table are mainly used in high-performance CNC wheel mortise and tenon broaching machines, machining centers and other CNC equipment. They can improve the mean time between failures (MTBF) of CNC machine tools, increase the yield and production efficiency, and reduce the maintenance cost of machine tools.

[0004] CNC rotary tables are equipped with braking devices to control them and keep them stationary at a certain position. Currently, there are three common types of braking devices: hydraulic braking devices, braking devices combining friction pad assemblies and hydraulic cylinders, and braking devices combining multiple sets of mechanical braking devices and hydraulic cylinders.

[0005] The patent, number 202210591360.8, entitled "A CNC Rotary Table Structure," provides a hydraulic braking device solution. A piston cylinder is fixed inside a housing, a piston is installed inside the piston cylinder, and a piston cover is fixed to the piston cylinder. The piston and piston cylinder form an upper oil chamber, and the piston and piston cover form a lower oil chamber. When oil is supplied to the lower oil chamber, the piston and the worktable move upward together to achieve a hydraulic unlocking function; when oil is supplied to the upper oil chamber, the piston and the worktable move downward axially together to achieve a hydraulic braking function. However, the patent does not provide braking redundancy measures. Once the braking device experiences leakage or seal failure, the braking force will be lost, the CNC rotary table will lose its function, and ultimately the workpiece will be scrapped and the machine tool will stop.

[0006] The patent, number 202111133840.1, entitled "A Friction Plate Assembly, a Brake Assembly, and a CNC Turntable," provides a braking scheme combining a friction plate assembly and a hydraulic cylinder. By installing friction plates on the stator and rotor assemblies of the CNC turntable, pressure is applied by the hydraulic cylinder to press the friction plates on the stator and rotor assemblies when the rotor assembly needs to be stopped; when the rotor assembly needs to be rotated, no pressure is applied, allowing the rotor to rotate freely, thus improving the braking performance of the friction plates. However, over time, the interaction between the friction plates causes the braking performance to gradually decrease, affecting the positioning accuracy of the CNC turntable and failing to meet the requirements of high-precision CNC machining. The patent does not provide redundancy measures; if the friction plates fail or the hydraulic cylinder malfunctions, the braking device becomes unusable, the CNC turntable loses function, leading to workpiece scrap and machine tool downtime.

[0007] The patent, numbered 202211084611.X and titled "A Small CNC Indexing Rotary Table Device," provides a braking scheme comprising multiple sets of mechanical braking devices combined with hydraulic cylinders. The mechanical braking device includes disc springs, bolts, pressure plates, pistons, hydraulic cylinders, and seals. The pistons and disc springs are disposed in piston holes on the CNC rotary table base. The hydraulic cylinder cover and stator form a hydraulic actuation device. The braking device is fixed to the hydraulic cylinder cover by bolts, simultaneously applying pressure to press the stator assembly and rotor assembly, achieving mechanical braking. When it is necessary to control the rotation of the rotor assembly, hydraulic oil is used to push the hydraulic cylinder cover to move, creating a gap between the stator assembly and rotor assembly, thereby unlocking and allowing the rotor to rotate freely, achieving hydraulic unlocking. By setting up a mechanical braking device, the patent avoids the loss of braking function due to hydraulic system seal failure, improving the reliability of the braking function. However, the patent does not provide redundancy measures. Although multiple braking devices are set up, these devices are connected in series. If any one of the mechanical braking devices fails, reliable braking and unlocking functions cannot be achieved, causing the CNC turntable to stop working.

[0008] A braking device structure with redundant functions and a CNC rotary table have three main features: 1) The braking devices all adopt a redundant structure design, with the braking force being borne by multiple parts simultaneously, resulting in long service life, reliable performance, and high safety; 2) The braking of the worktable is completed by multiple sets of braking devices, which have parallel characteristics in function, resulting in high reliability; 3) The accuracy retention time is long. Summary of the Invention

[0009] To address the shortcomings of existing braking device structures, such as lack of redundancy and low reliability, this invention provides a braking device structure with redundancy and a CNC rotary table.

[0010] The technical solution of the present invention is as follows:

[0011] A braking device structure with redundant functions includes a locking screw, a locking nut, a sealing piston cylinder, an upper washer, a spring, a lower washer, and a pressure block. The locking screw is fixed to the pressure plate by a threaded connection. The sealing piston cylinder is sleeved outside the locking screw and is fixedly connected to the pressure plate by a thread. The locking nut is threaded to the sealing piston cylinder. The lower washer, spring, and upper washer are sequentially mounted on the sealing piston cylinder. By rotating the locking nut, the spring is compressed, generating braking force. A pressure block is provided at the top of the sealing piston cylinder. The preload applied by the locking screw is transmitted to the sealing piston cylinder through the pressure block and is in contact with the locking nut.

[0012] Furthermore, a sealing gasket is provided between the locking screw and the pressure block, and a sealing gasket is provided between the pressure block and the sealing piston cylinder.

[0013] Furthermore, a sealing gasket is provided between the lower end of the sealed piston cylinder and the pressure plate to prevent hydraulic oil from leaking from the sealed piston cylinder.

[0014] Furthermore, the length by which the locking screw is screwed into the support allows for adjustment of the preload.

[0015] Furthermore, the outer wall of the sealed piston cylinder is provided with a sealing ring to prevent hydraulic oil from leaking from the piston hole.

[0016] Furthermore, the axial stiffness of the sealed piston cylinder is less than the axial stiffness of the screw.

[0017] Furthermore, the hardness of the upper and lower pads is higher than that of the spring.

[0018] A CNC rotary table with a redundant braking device structure includes a worktable, a base, a worm gear transmission mechanism, and a pressure plate. A bushing is provided on the base, and a bearing is mounted on the bushing. A main spindle is located inside the bushing, and an angular displacement sensor is located at the lower end of the main spindle. The main spindle is connected to the worm gear transmission mechanism. The pressure plate is connected to the bushing and forms a hydraulic cylinder with the base (an oil passage is provided between the pressure plate and the base). Multiple braking devices, as described in any one of claims 1-7, are provided between the base and the pressure plate. These multiple braking devices act simultaneously to achieve mechanical braking of the worktable.

[0019] Furthermore, the multiple sets of braking devices are arranged in a ring around the circumference of the base.

[0020] Furthermore, the worm gear transmission mechanism includes a geared motor, a worm gear, a worm, and a timing belt.

[0021] The beneficial effects of this invention are as follows:

[0022] 1) This invention discloses a highly reliable braking device structure with redundancy, comprising: a locking nut, an upper washer, a spring, a lower washer, a sealing ring, a sealing piston cylinder, a sealing gasket, a pressure block, a locking screw, a piston, and a base; the braking device is installed in a mounting hole in the base; the sealing ring is installed in a sealing groove on the base; the sealing piston cylinder is fixed to the pressure plate by threads; a sealing gasket is installed between the lower end of the sealing piston cylinder and the piston; the lower washer, spring, and upper washer are sequentially mounted on the sealing piston cylinder, and braking force is generated by compressing the spring by rotating the locking nut; a sealing gasket is installed between the screw and the pressure block, and the pressure... A sealing gasket is installed between the block and the sealing piston cylinder; the locking screw is fixed to the support by a threaded connection, and the preload is adjusted by adjusting the length of the screw screw into the support; the pressure block is in contact with the locking nut under the preload applied by the locking screw; the preload applied by the screw is transmitted to the sealing piston cylinder in sequence through the sealing gasket, the pressure block, and the sealing gasket; the sealing ring is used to prevent hydraulic oil from leaking from the piston hole; the sealing gasket is used to prevent hydraulic oil from leaking from the sealing piston cylinder; each braking device adopts a redundant structure design, and the braking force is shared by the brake screw and the sealing piston cylinder, resulting in long service life, reliable performance, and high safety.

[0023] 2) The present invention provides a braking device structure with redundant functions and a CNC rotary table, comprising multiple sets of braking devices with redundant functions. A cover plate is provided on the base, a bushing is provided on the base, a bearing is mounted on the bushing, a main shaft is provided inside the bushing, an encoder is provided at the lower end of the main shaft, the main shaft is connected to a worm gear transmission mechanism, and a set of braking devices is provided on the base, and the set of braking devices is arranged in a ring around the base. The mechanical braking of the worktable can be achieved through the set of braking devices, with high reliability and safety.

[0024] 3) The present invention provides a braking device structure and CNC rotary table with redundant functions. The mechanical braking of the worktable can be achieved by a set of braking devices. Each braking device has a redundant structure and is connected in parallel. The braking device structure composed of a set of braking devices has a long service life and higher reliability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the external structure of the present invention;

[0026] Figure 2 This is a bottom-view structural diagram of the present invention;

[0027] Figure 3 This is a schematic diagram of the transmission structure of the present invention;

[0028] Figure 4 This is a schematic diagram of the AA cross-sectional structure of the present invention;

[0029] Figure 5 This is a schematic cross-sectional view of the braking device of the present invention;

[0030] In the diagram: 1. Worktable; 2. Base; 3. Gear motor; 4. Synchronous belt; 5. Worm gear; 6. Worm wheel; 7. Screw a; 8. Pressure plate; 9. Screw b; 10. Bushing; 11. Screw c; 12. Oil passage; 13. Bearing; 14. Support plate; 15. Screw d; 16. Angular displacement sensor; 17. Coupling; 18. Screw e; 19. Spindle; 20. Cover plate; 21. Screw f; 22. Braking device; 23. Locking nut; 24. Upper washer; 25. Spring; 26. Lower washer; 27. Sealing ring; 28. Sealing piston cylinder; 29. ​​Sealing gasket a; 30. Pressure block; 31. Sealing gasket b; 32. Sealing gasket c; 33. Locking screw. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] like Figure 1-5 As shown, a braking device structure with redundant functions and a CNC rotary table are rectangular in shape, with total dimensions (including the motor) of length × width × height = 1450mm × 1300mm × 300mm. It mainly includes: a worktable 1, a base 2, a geared motor 3, a synchronous belt 4, a worm gear 5, a worm wheel 6, a pressure plate 8, a bushing 10, a support plate 14, an angular displacement sensor 16, a coupling 17, a spindle 19, a cover plate 20, and 36 sets of braking devices 22.

[0033] The specific structure is as follows:

[0034] The geared motor 3 is mounted and fixed on the base 2. The worm gear 5 is supported and fixed on the base 2 by bearings at both ends. The worktable 1 is fixed to the worm wheel 6 by screws 7. The geared motor 3 drives the worm gear 5 to rotate via the synchronous belt 4. The worm gear 5 drives the worm wheel 6 to rotate. The worm wheel 6 moves synchronously with the worktable 1. The spindle 19 moves synchronously with the worktable 1 through an interference fit. The pressure plate 8 is fixed to the bushing 10 by screws 9. The bushing 10 is fixed to the base 2 by screws c11. Bearings are mounted on the bearing bushing 10. 13. The support plate 14 is fixed to the main shaft 19 by screw d15. The angular displacement sensor 16 is connected to the main shaft 19 by coupling 17. The angular displacement sensor 16 is fixed to the cover plate 20 by screw e18. The cover plate 20 is fixed to the base 2 by screw f21. The braking device 22 is installed in the 36 mounting holes provided on the base 2. The pressure plate 8 contacts the worm gear 6 through the braking pressure applied by the braking device 22. The pressure plate 8 and the annular oil groove provided on the base 2 form a set of hydraulic cylinders.

[0035] The base 2 is provided with mounting holes for the braking device 22. The sealing ring 27 is installed in the sealing groove of the base 2. The sealing piston cylinder 28 is fixed to the pressure sleeve 8 by threads. A sealing gasket a29 is installed between the lower end of the sealing piston cylinder 28 and the piston. The lower gasket 26, the spring 25 (butterfly spring), and the upper gasket 24 are sequentially installed on the sealing piston cylinder 28. By rotating the locking nut 23, the upper gasket 24 is driven to compress the spring 25 downward, generating pressure that causes the pressure plate 8 to move downward and generate braking force. A seal is installed between the locking screw 33 and the pressure block 30. A sealing gasket b31 is installed between the gasket c32, the pressure block 30 and the sealing piston cylinder 28. The locking screw 33 is fixed to the base 2 by a threaded connection. The preload is adjusted by the length of the locking screw 33 screwed into the support. The pressure block 30 fits with the brake nut 23. The preload of the screw 33 is transmitted to the sealing piston cylinder 28 in sequence through the sealing gasket 32, the pressure block 30 and the sealing gasket 31. Multiple braking devices are arranged in a ring around the base 1 to achieve axial mechanical braking of the turntable spindle. In this embodiment, a total of 36 braking devices are installed.

[0036] During operation, the geared motor 3 is energized, driving the worm gear 5 to rotate via the synchronous belt 4. The worm gear 5 drives the worm wheel 6, which in turn drives the worktable 1 to rotate. The worktable can rotate clockwise or counterclockwise and can stop at any angle. The indexing detection of the worktable is achieved through the angular displacement sensor 16. The oil chamber formed by the base 2 and the pressure plate 8 is connected to the external hydraulic system circuit. When the worktable 1 rotates and indexes, hydraulic oil is supplied through the oil circuit 12 to make the pressure plate 8 overcome the braking force and move, disengaging from the worm wheel 6, i.e., hydraulic unlocking. When cutting operations are performed, the hydraulic oil is released, and under the pressure applied by the braking device 22, the pressure plate 8 presses against the worm wheel 6, i.e., mechanical braking is performed. Specifically: When the oil circuit drains, the locking nut 23 in each braking device, under the elastic force applied by the disc spring 25, forces the pressure plate 8 to press against the worm gear 6, achieving braking under the combined action of 36 braking devices 22; when hydraulic oil enters the oil chamber formed by the pressure plate 8 and the base 2 through the oil circuit 12, the disc spring 25 tightens, causing the pressure plate 8 to disengage from the worm gear 6, achieving the purpose of mechanical braking unlocking; when the braking device is in both braking and unlocking states, the elastic force applied by the disc spring 25 is shared by the locking nut 23 and the locking screw 33, significantly reducing the load borne by the locking nut 23 and the locking screw 33, thereby increasing their service life.

[0037] CNC indexing rotary tables are widely used in machine tools, such as machining centers, CNC lathes, CNC grinding machines, and CNC milling machines. This invention uses a braking device with redundant functions to ensure that the CNC rotary table has a long service life, improve the mean time between failures (MTBF) of the machine tool, increase the yield and production efficiency, and reduce the maintenance cost of the machine tool.

Claims

1. A braking device structure with redundancy, characterized in that, It includes a locking screw, a locking nut, a sealing piston cylinder, an upper washer, a spring, a lower washer, and a pressure block; the braking device adopts a redundant structural design, with the braking force shared by the locking screw and the sealing piston cylinder. The locking screw is fixed to the pressure plate by a threaded connection. The sealing piston cylinder is sleeved outside the locking screw and is fixedly connected to the pressure plate by a thread. The locking nut is threaded to the sealing piston cylinder. The lower washer, spring, and upper washer are sequentially mounted on the sealing piston cylinder. By rotating the locking nut, the spring is compressed, generating braking force. The top of the sealing piston cylinder is provided with a pressure block. The preload applied by the locking screw is transmitted to the sealing piston cylinder through the pressure block and is in contact with the locking nut. The length by which the locking screw is screwed into the support allows for adjustment of the preload, and the axial stiffness of the sealing piston cylinder is less than the axial stiffness of the screw.

2. The braking device structure with redundancy function according to claim 1, characterized in that, A sealing gasket is provided between the locking screw and the pressure block, and a sealing gasket is provided between the pressure block and the sealing piston cylinder.

3. The braking device structure with redundancy function according to claim 1, characterized in that, A sealing gasket is provided between the lower end of the sealed piston cylinder and the pressure plate to prevent hydraulic oil from leaking out of the sealed piston cylinder.

4. The braking device structure with redundancy function according to claim 1, characterized in that, The outer wall of the sealed piston cylinder is provided with a sealing ring to prevent hydraulic oil from leaking from the piston hole.

5. The braking device structure with redundancy function according to claim 1, characterized in that, The hardness of the upper and lower washers is higher than that of the spring.

6. A CNC rotary table with a redundant braking device structure, characterized in that, The device includes a worktable, a base, a worm gear transmission mechanism, and a pressure plate. A bushing is mounted on the base, and a bearing is installed on the bushing. A main shaft is located inside the bushing, and an angular displacement sensor is located at the lower end of the main shaft. The main shaft is connected to the worm gear transmission mechanism. The pressure plate is connected to the bushing and forms a hydraulic cylinder with the base. Multiple braking devices as described in any one of claims 1-5 are provided between the base and the pressure plate. These multiple braking devices act simultaneously to achieve mechanical braking of the worktable.

7. A CNC rotary table with a redundant braking device structure according to claim 6, characterized in that, The multiple braking devices are arranged in a uniform ring.

8. A CNC rotary table with a redundant braking device structure according to claim 6, characterized in that, The worm gear transmission mechanism includes a geared motor, a worm gear, a worm, and a timing belt.

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