Brake structure of direct-drive rotary table

Abstract

The utility model belongs to the technical field of machine tool equipment, and relates to a direct-drive rotary table brake structure which comprises a base and a main shaft rotationally arranged on the base, a shell is arranged outside the base and the main shaft in a covering mode, the shell is fixedly connected with the base and is in clearance fit with the main shaft, and an annular cavity is formed among the shell, the base and the main shaft. An oil brake drum is arranged at the position, corresponding to the spindle, of the cavity, a piston is arranged at the position, corresponding to the base, of the cavity, and an oil cavity connected with an oil pump is formed in the rear side of the piston. In the initial state, the oil brake drum is in clearance fit with the spindle, when hydraulic oil is injected into the oil cavity and drives the piston to move forwards, the piston extrudes the oil brake drum, and the oil brake drum brakes the spindle after generating radial deformation. The brake structure of the direct-drive rotary table has the advantages of being high in brake precision, high in response speed, short in brake distance and long in service life.

Description

Technical Field

[0001] This utility model belongs to the technical field of machine tool equipment and relates to a direct drive rotary table brake structure. Background Technology

[0002] Machine tool rotary tables are generally equipped with braking mechanisms, which are key functional modules for achieving high-precision and high-reliability machining. Existing rotary table braking mechanisms generally use axial braking, which uses a power system to push friction plates axially against the end face of the rotating part to form braking.

[0003] Chinese utility model patent CN219725256U (publication date: 2023-09-22) discloses such a typical braking mechanism, specifically a four-axis rotary table disc hydraulic brake mechanism, including a rotary table body, a static friction plate, a brake valve core, a brake end cover, a dynamic friction plate, a rotary worktable, and a spring plunger. The rotary table body is a four-axis rotary table. The hydraulic brake mechanism is designed between the rotary table body and the brake end cover. The brake valve core is connected to the rotary table body. The dynamic friction plate is connected to the side of the brake valve core near the rotary worktable. The brake end cover is set on the side of the dynamic friction plate near the rotary worktable. The static friction plate is fixedly connected to the side of the brake end cover near the brake valve core. The spring plunger is embedded in the brake end cover.

[0004] Existing axial braking mechanisms have many shortcomings: friction pad braking causes bending deformation of the main shaft, reducing its runout accuracy; friction pads experience significant wear during braking, thus the service life of this braking structure is generally short. Utility Model Content

[0005] This invention addresses the shortcomings of existing technologies by providing a direct-drive turntable braking structure, which has the advantages of high braking accuracy, fast response speed, short braking distance, and long service life.

[0006] To solve the above-mentioned technical problems, the objective of this utility model is achieved through the following technical solution:

[0007] A direct-drive turntable braking structure includes a base and a main shaft rotatably mounted on the base. The base and main shaft are covered by a housing. The housing is fixed to the base and has a clearance fit with the main shaft. An annular cavity is formed between the housing, the base, and the main shaft. A hydraulic brake drum is provided at the location corresponding to the main shaft and a piston is provided at the location corresponding to the base. An oil chamber connected to an oil pump is formed on the rear side of the piston. In the initial state, the hydraulic brake drum has a clearance fit with the main shaft. When hydraulic oil is injected into the oil chamber and drives the piston to move forward, the piston squeezes the hydraulic brake drum, and the hydraulic brake drum undergoes radial deformation, thus braking the main shaft.

[0008] In the aforementioned direct-drive turntable brake structure, the outer shell, piston, oil chamber, and oil brake drum are all coaxial annular structures; furthermore, the piston and oil brake drum are coaxially arranged with the main shaft.

[0009] In the aforementioned direct-drive turntable brake structure, the base is provided with a first mounting step that mates with the housing, the main shaft is provided with a second mounting step that mates with the base, and the front end of the housing is provided with an inner edge ring that is clearance-fitted with the main shaft. The inner edge ring forms the front axial limiting structure of the hydraulic brake drum.

[0010] In the aforementioned direct-drive turntable brake structure, an oil inlet connected to an oil pump is provided on the outer wall of the base. The oil inlet is connected to the oil chamber through an oil inlet channel. Specifically, the oil inlet channel includes a radial channel and an axial channel arranged in sequence. The oil inlet is connected to the radial channel, the radial channel is connected to the axial channel, and the axial channel is connected to the oil chamber.

[0011] In the aforementioned direct-drive turntable brake structure, a first sealing ring is provided between the outer wall of the piston and the inner wall of the housing, a second sealing ring is provided between the inner wall of the piston and the base, and a third sealing ring is provided between the inner wall of the rear end of the housing and the outer wall of the base. The first sealing ring, the second sealing ring, and the third sealing ring form an oil cavity sealing structure.

[0012] In the aforementioned direct-drive turntable brake structure, the hydraulic brake drum has a thin-walled corrugated structure.

[0013] In the above-mentioned direct-drive turntable brake structure, the hydraulic brake drum is made of an alloy material that can produce elastic deformation in the art, such as spring steel. Preferably, the spring steel is coated with NiCrBSi alloy.

[0014] In the aforementioned direct-drive turntable brake structure, the oil brake drum has multiple bent planes. Its front end face forms a front limiting surface that contacts the inner edge ring of the outer shell, its rear end face forms a rear limiting surface that contacts the piston, its front and rear parts respectively form outer limiting surfaces that contact the inner wall of the outer shell, and its middle part forms a braking surface corresponding to the outer wall of the main shaft.

[0015] In the aforementioned direct-drive turntable braking structure, preferably, the axial dimension of the braking surface is larger than that of the outer limiting surface.

[0016] Compared with the prior art, this utility model has the following advantages:

[0017] This invention provides a direct-drive turntable brake structure. It uses hydraulic pressure to drive the piston axially, compressing the hydraulic brake drum and causing radial deformation. This reduces the inner diameter of the brake drum, creating a contact surface between its inner circumference and the outer circumference of the main shaft. The compression and friction achieve the braking effect. This invention employs a radial braking structure. During braking, the evenly distributed contact pressure aligns the line of action of the braking force with the main shaft axis, completely eliminating the bending moment generated by axial or tangential braking and preventing a decrease in running accuracy due to main shaft deformation and bending. The hydraulic brake drum of this invention achieves braking through the elastic deformation of the material, reducing wear on traditional friction pads and extending the life of the braking mechanism. Furthermore, this invention also has the advantages of fast braking response and short braking distance. Attached Figure Description

[0018] Figure 1 This is a top view of the present invention;

[0019] Figure 2 yes Figure 1 Axial sectional view;

[0020] Figure 3 This is a cross-sectional view of the hydraulic brake drum of this utility model;

[0021] Reference numerals in the attached drawings: 1. Base; 2. Main shaft; 3. Housing; 4. Oil brake drum; 5. Piston; 6. Oil chamber; 7. First mounting step; 8. Second mounting step; 9. Inner edge ring; 10. Oil inlet; 11. Oil inlet channel; 12. First sealing ring; 13. Second sealing ring; 14. Third sealing ring; 15. Front limiting surface; 16. Rear limiting surface; 17. Outer limiting surface; 18. Braking surface. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. See also: Figure 1-3 :

[0023] A direct-drive turntable braking structure includes a base 1 and a main shaft 2 rotatably mounted on the base 1. The base 1 and the main shaft 2 are covered by a housing 3. The housing 3 is fixed to the base 1 and has a clearance fit with the main shaft 2. An annular cavity is formed between the housing 3, the base 1, and the main shaft 2. A hydraulic brake drum 4 is provided at the position corresponding to the main shaft 2 in the cavity, and a piston 5 is provided at the position corresponding to the base 1. An oil chamber 6 connected to an oil pump is formed on the rear side of the piston 5. In the initial state, the hydraulic brake drum 4 has a clearance fit with the main shaft 2. When hydraulic oil is injected into the oil chamber 6 and drives the piston 5 to move forward, the piston 5 squeezes the hydraulic brake drum 4, and the hydraulic brake drum 4 undergoes radial deformation and brakes the main shaft 2.

[0024] During operation, the power unit, such as a direct-drive motor, drives the spindle 2 to rotate. At this time, the inner circumferential surface of the hydraulic brake drum 4 is in clearance fit with the outer circumferential surface of the spindle 2, which does not affect the operation of the spindle 2. When braking is required, hydraulic oil is injected into the oil chamber 6. The piston 5 moves forward under hydraulic drive and squeezes the hydraulic brake drum 4. The hydraulic brake drum 4 undergoes elastic deformation, and its inner diameter shrinks. The inner circumferential surface of the hydraulic brake drum 4 makes contact with the outer circumferential surface of the spindle 2, and squeezes and rubs on the contact surface to produce a braking effect, causing the spindle 2 to stop rotating.

[0025] In this embodiment, the outer shell 3, piston 5, oil chamber 6 and oil brake drum 4 are all coaxial annular structures; in order to obtain a circumferentially distributed contact pressure during braking, the piston 5, oil brake drum 4 and main shaft 2 are coaxially arranged.

[0026] Comparison Appendix Figure 2 The base 1 is provided with a first mounting step 7 that mates with the outer shell 3, the main shaft 2 is provided with a second mounting step 8 that mates with the base 1, and the front end of the outer shell 3 is provided with an inner edge ring 9 that is clearance-fitted with the main shaft 2. The inner edge ring 9 forms the front axial limiting structure of the oil brake drum 4.

[0027] In this embodiment, the oil circuit is configured as follows: an oil inlet 10 for connecting to an oil pump is provided on the outer wall of the base 1. The oil inlet 10 is connected to the oil cavity 6 through an oil inlet channel 11. Specifically, the oil inlet channel 11 includes a radial channel and an axial channel arranged in sequence. The oil inlet 10 is connected to the radial channel, the radial channel is connected to the axial channel, and the axial channel is connected to the oil cavity 6. The above-mentioned oil circuit structure makes processing easier and the flow of hydraulic oil smoother.

[0028] The sealing structure of the oil cavity 6 in this embodiment is as follows: a first sealing ring 12 is provided between the outer wall of the piston 5 and the inner wall of the outer shell 3, a second sealing ring 13 is provided between the inner wall of the piston 5 and the base 1, and a third sealing ring 14 is provided between the inner wall of the rear end of the outer shell 3 and the outer wall of the base 1. The first sealing ring 12, the second sealing ring 13 and the third sealing ring 14 form the sealing structure of the oil cavity 6.

[0029] The aforementioned oil brake drum 4 has a thin-walled corrugated structure to enhance its deformation capability.

[0030] The aforementioned oil brake drum 4 uses spring steel as the base material. At the same time, the spring steel is subjected to surface treatment processes such as shot peening to improve its fatigue limit. In addition, NiCrBSi alloy can be clad on the spring steel to improve its wear resistance.

[0031] Comparison Appendix Figure 3The hydraulic brake drum 4 has multiple bent planes. Its front end face forms a front limiting surface 15 that contacts the inner edge ring 9 of the outer shell 3, and its rear end face forms a rear limiting surface 16 that contacts the piston 5. The front and rear parts respectively form outer limiting surfaces 17 that contact the inner wall of the outer shell 3, and the middle part forms a braking surface 18 that corresponds to the outer wall of the main shaft 2. In the initial state, the front limiting surface 15, the rear limiting surface 16, and the outer limiting surface 17 form the limiting structure of the hydraulic brake drum 4, making its installation structure more stable. At the same time, during the deformation process, it restricts the hydraulic brake drum 4 from generating deformation in both directions and outwards, and concentrates its deformation in the inward direction, resulting in a better braking effect.

[0032] In this embodiment, the axial dimension of the braking surface 18 is larger than that of the outer limiting surface 17. By increasing the area of ​​the braking surface 18, the area of ​​the contact surface during braking can be increased, thereby enhancing the braking effect.

[0033] The above embodiments are merely preferred embodiments of the present utility model and are not intended to limit the scope of protection of the present utility model. Therefore, all equivalent changes made to the structure, shape, and principle of the present utility model should be covered within the scope of protection of the present utility model.

Claims

1. A direct-drive turntable braking structure, comprising a base (1) and a main shaft (2) rotatably mounted on the base (1), characterized in that, The base (1) and the main shaft (2) are covered by a shell (3). The shell (3) is fixed to the base (1) and has a clearance fit with the main shaft (2). The shell (3) forms an annular cavity with the base (1) and the main shaft (2). The cavity is provided with a hydraulic brake drum (4) corresponding to the main shaft (2) and a piston (5) corresponding to the base (1). An oil chamber (6) connected to the oil pump is formed on the rear side of the piston (5). In the initial state, the hydraulic brake drum (4) is in clearance fit with the main shaft (2). When hydraulic oil is injected into the oil chamber (6) and drives the piston (5) to move forward, the piston (5) squeezes the hydraulic brake drum (4). The hydraulic brake drum (4) generates radial deformation and brakes the main shaft (2).

2. The direct-drive turntable braking structure according to claim 1, characterized in that, The base (1) is provided with a first mounting step (7) that cooperates with the outer shell (3), the main shaft (2) is provided with a second mounting step (8) that cooperates with the base (1), and the front end of the outer shell (3) is provided with an inner edge ring (9) that is clearance-fitted with the main shaft (2). The inner edge ring (9) forms the front axial limiting structure of the oil brake drum (4).

3. The direct-drive turntable braking structure according to claim 2, characterized in that, The base (1) has an oil inlet (10) connected to the oil pump on its outer wall. The oil inlet (10) is connected to the oil chamber (6) through the oil inlet channel (11).

4. The direct-drive turntable braking structure according to claim 3, characterized in that, A first sealing ring (12) is provided between the outer wall of the piston (5) and the inner wall of the outer shell (3), a second sealing ring (13) is provided between the inner wall of the piston (5) and the base (1), and a third sealing ring (14) is provided between the inner wall of the rear end of the outer shell (3) and the outer wall of the base (1). The first sealing ring (12), the second sealing ring (13) and the third sealing ring (14) form an oil cavity (6) sealing structure.

5. The direct-drive turntable braking structure according to claim 1, characterized in that, The oil brake drum (4) has a thin-walled corrugated structure.

6. The direct-drive turntable braking structure according to claim 1, characterized in that, The oil brake drum (4) has multiple bent planes. Its front end face forms a front limiting surface (15) that contacts the inner edge ring (9) of the outer shell (3), and its rear end face forms a rear limiting surface (16) that contacts the piston (5). The front and rear parts respectively form an outer limiting surface (17) that contacts the inner wall of the outer shell (3), and the middle part forms a braking surface (18) that corresponds to the outer wall of the main shaft (2).

7. The direct-drive turntable braking structure according to claim 6, characterized in that, The axial dimension of the braking surface (18) is greater than that of the outer limiting surface (17).

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