Built-in brake lathe spindle

Abstract

This utility model relates to a lathe spindle with a built-in brake. The front end of the spindle is connected to a front end cover via a front end bearing assembly. The front end cover is fixed to the front end of the housing and contacts the front end of the spindle. The front end cover presses against the outer ring of the front end bearing assembly, and a locking nut presses against the inner ring of the front end bearing assembly. It includes a built-in braking mechanism, which consists of a wave spring seat, a hydraulic cylinder seat, a brake positioning disc, a brake disc, a hydraulic cylinder piston, and a wave spring assembly. This compact built-in braking mechanism improves space utilization. By integrating the braking mechanism, consisting of a brake positioning disc, a wave spring assembly, and a hydraulic cylinder piston, at the tail end of the spindle, an integrated design of the braking system and the spindle is achieved. This structure eliminates the need for an external braking device, significantly reducing the overall size and making it suitable for high-precision lathe layouts with limited space. It also reduces positioning deviations caused by external vibrations.

Description

Technical Field

[0001] This utility model relates to the field of CNC lathe spindle braking technology, specifically a lathe spindle structure with built-in brake. By integrating a hydraulic braking mechanism with the spindle body, it solves the problems of large space occupation, insufficient braking torque, and low positioning accuracy of traditional external braking systems. Background Technology

[0002] The lathe spindle is a key functional component of a lathe, and it is divided into mechanical spindles and electric spindles. Besides requiring high speed and large torque, it also needs precise positioning to achieve accurate machining. Currently, lathe brakes are generally separate, installed at the rear of the lathe, where a brake disc is mounted. The braking mechanism is a single-point brake, relying on the frictional force of the brake disc to brake the lathe. This braking method, due to its relatively small contact area, results in low braking torque. Therefore, it affects the spindle's accuracy and also occupies additional external space.

[0003] Existing technology, Chinese patent CN114713862A, provides a built-in braking mechanism for a lathe spindle. It employs a separate external braking mechanism, with the brake disc mounted at the rear end of the spindle, achieving braking through single-point friction braking. Its drawbacks are: small contact area, limited braking torque due to single-point friction, and reduced braking force due to thermal fade with frequent braking. Furthermore, it occupies a large space, requiring additional brackets (such as horizontal and vertical support rods) for the external structure, increasing the spindle box volume. Moreover, uneven force during braking can easily cause radial runout of the spindle, affecting machining accuracy.

[0004] In view of the above-mentioned shortcomings, the designer actively researched and innovated in order to create a lathe spindle with built-in brake, which would make it more valuable for industrial use. Utility Model Content

[0005] To solve the above-mentioned technical problems, the purpose of this utility model is to provide a lathe spindle with built-in brake.

[0006] The built-in brake lathe spindle of this utility model includes a spindle, a front end cover, a housing, a motor rotor, a motor stator, a rear bearing housing, and a rear end cover, wherein: the front end of the spindle is connected to the front end cover through a front end bearing assembly, the front end cover is fixed to the front end of the housing and contacts the front end of the spindle; the front end cover presses against the outer ring of the front end bearing assembly, and the locking nut presses against the inner ring of the front end bearing assembly; The motor rotor is interference-fitted and sleeved on the outer side of the middle part of the spindle, and the motor stator is sleeved on the outer side of the motor rotor and fixed in the housing by heat fitting. The rear bearing housing is fixed to the rear end of the housing, and a rear cylindrical roller bearing is installed inside the rear bearing housing to support the tail of the spindle; the rear bearing housing is connected to a rear end cap. It also includes a built-in braking mechanism, which consists of a wave spring seat, a cylinder seat, a brake positioning disc, a brake disc, a cylinder piston, and a wave spring assembly. The brake positioning disc is fixed between the wave spring seat and the cylinder seat. The front end of the piston return pin is connected to the piston return disc, and the rear end of the piston return pin is connected to the cylinder piston. A cylinder cavity is installed on the cylinder piston. A wave spring assembly is connected to the piston return disc. The hydraulically driven cylinder piston pushes the brake positioning disc, forming a 360° circumferential friction braking with the brake disc. When the hydraulic pressure is unloaded, the wave spring assembly resets the brake positioning disc through the piston reset pin.

[0007] Furthermore, in the aforementioned built-in brake lathe spindle, the front bearing assembly includes a first precision angular contact bearing, a second precision angular contact bearing, and a third precision angular contact bearing; the front bearing assembly also includes an inner spacer and an outer spacer located between the second precision angular contact bearing and the third precision angular contact bearing, the inner spacer contacting the spindle and the outer spacer contacting the housing; the thickness difference between the inner and outer spacers is 0.02 to 0.05 mm.

[0008] Furthermore, in the aforementioned built-in brake lathe spindle, the interference fit surface between the motor rotor and the spindle has axial keyways distributed on the spindle, and the depth of the axial keyways is 1 / 100 to 1 / 80 of the spindle diameter.

[0009] Furthermore, in the aforementioned built-in brake lathe spindle, an adjusting spacer is installed at the front end of the rear cylindrical roller bearing to adjust the preload of the rear cylindrical roller bearing.

[0010] Furthermore, in the aforementioned built-in brake lathe spindle, the rear end of the rear cylindrical roller bearing is pressed and positioned by a first rear inner spacer and a second rear inner spacer; the second rear inner spacer contacts the front end of the brake disc, and the rear end of the brake disc contacts the third rear inner spacer.

[0011] Furthermore, in the aforementioned built-in brake lathe spindle, the wave spring assembly consists of three spring bodies arranged in parallel, and the pre-compression of the spring bodies is 0.5-1.2mm.

[0012] Furthermore, in the aforementioned built-in brake lathe spindle, the rear end cap and the rear bearing housing are fixed by a first set screw and a second set screw.

[0013] Furthermore, in the aforementioned built-in brake lathe spindle, the friction surface of the brake positioning disc is provided with radial grooves, the width of which is 2 to 3 mm and the depth is 0.3 to 0.5 mm.

[0014] Furthermore, in the aforementioned built-in brake lathe spindle, the cylinder cavity includes a first cylinder piston connected to a piston reset pin. An upper cylinder seal is fitted on the upper end of the first cylinder piston, a lower cylinder seal is fitted on the lower end of the first cylinder piston, and a cylinder seat is fitted on the outside of the first cylinder piston.

[0015] Furthermore, in the aforementioned built-in brake lathe spindle, the rear end of the spindle is connected to a connecting disc via an auxiliary screw.

[0016] By means of the above solution, this utility model has at least the following advantages: 1. A compact, built-in braking mechanism improves space utilization. By integrating a braking mechanism consisting of a brake positioning disc, wave spring assembly, and hydraulic cylinder piston at the tail of the spindle, the braking system and spindle are integrated into a single design. This structure eliminates the need for an external braking device, significantly reducing the overall size and making it suitable for high-precision lathe layouts with limited space. It also reduces positioning deviations caused by external vibrations.

[0017] 2. The hydraulically driven cylinder piston pushes the brake positioning disc to form a uniform circumferential contact with the brake disc, maximizing the friction area. The braking torque can be linearly adjusted, and the braking intensity can be adjusted in real time by external hydraulic pressure to adapt to the needs of emergency stop or slow stop under different working conditions.

[0018] 3. The front bearing assembly adopts a front bearing assembly, and with the inner / outer spacer tolerance control, the axial load is evenly distributed, avoiding the problem of uneven wear caused by single bearing overload.

[0019] 4. The preload of the rear cylindrical roller bearing is adjusted by adjusting the spacer ring, and it is pressed and positioned by double rear inner spacers to prevent loosening during operation; the rear end cover and the rear bearing housing are locked with double set screws to achieve redundant anti-loosening and high disassembly and maintenance efficiency.

[0020] 5. The cylinder cavity is composed of cylinder seals, cylinder piston and cylinder seat to form a closed circuit, which prevents hydraulic oil from seeping into the precision parts of the spindle and ensures cleanliness and stability during long-term operation.

[0021] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1This is a cross-sectional structural diagram of a lathe spindle with built-in brake.

[0023] The meanings of the labels in the figures are as follows. Detailed Implementation

[0024] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0025] like Figure 1 The built-in brake lathe spindle includes a spindle 1, a front cover 2, a housing 9, a motor rotor 10, a motor stator 11, a rear bearing housing 14, and a rear end cover 17. Its unique feature is that the front end of the spindle 1 is connected to the front cover 2 via a front bearing assembly, and the front cover 2 is fixed to the front end of the housing 9 and contacts the front end of the spindle 1. This ensures that the front bearing assembly does not affect the operation of the spindle 1 when the front cover 2 is installed and positioned. After installation, the front cover 2 presses against the outer ring of the front bearing assembly, and a locking nut 8 can be added to press against the inner ring of the front bearing assembly. Considering the transmission requirements during actual operation, the motor rotor 10 is interference-fitted onto the outer side of the middle of the spindle 1, and the motor stator 11 is fitted onto the outer side of the motor rotor 10 and fixed inside the housing 9 by a heat-fitting method. Meanwhile, the rear bearing housing 14 is fixed to the rear end of the housing 9, and a rear cylindrical roller bearing 13 is installed inside the rear bearing housing 14 to support the tail of the spindle 1. Considering the auxiliary limiting requirement of the rear bearing housing 14, the rear bearing housing 14 is connected to the rear end cover 17.

[0026] To achieve effective internal braking of the spindle, this invention also includes a built-in braking mechanism. It consists of a wave spring seat 19, a cylinder seat 23, a brake positioning disc 22, a brake disc 31, a cylinder piston 25, and a wave spring assembly 21. Specifically, the brake positioning disc 22 is fixed between the wave spring seat 19 and the cylinder seat 23. Simultaneously, the front end of the piston return pin 26 is connected to the piston return disc 29, and the rear end of the piston return pin 26 is connected to the cylinder piston 25, which has a cylinder cavity. Furthermore, to apply a reaction force to the cylinder piston 25, the wave spring assembly 21 is connected to the piston return disc 29. When braking is required, the hydraulically driven cylinder piston 25 pushes the brake positioning disc 22, forming a 360° circumferential friction braking with the brake disc 31. The magnitude of the friction force can be adjusted by the pressure of the external hydraulic oil. Furthermore, when the hydraulic pressure is released, the wave spring assembly 21 resets the brake positioning disc 22 via the piston return pin 26. During this period, under the action of the wave spring assembly 21, a reaction force is applied to the piston return pin 26, causing the brake disc 31 to disengage from the cylinder piston 25, thus completing the brake release action.

[0027] According to a preferred embodiment of this utility model, the front bearing assembly includes a first precision angular contact bearing 3, a second precision angular contact bearing 4, and a third precision angular contact bearing 7, achieving even force distribution among multiple bearings and preventing excessive local force that could lead to motion interference. Simultaneously, the front bearing assembly also includes an inner spacer 5 and an outer spacer 6 located between the second precision angular contact bearing 4 and the third precision angular contact bearing 7. During assembly, the inner spacer 5 contacts the spindle 1, and the outer spacer 6 contacts the housing 9. To accommodate assembly tolerances, the thickness difference between the inner spacer 5 and the outer spacer 6 is 0.02 to 0.05 mm.

[0028] Looking further, the motor rotor 10 and the spindle 1 have an interference fit surface. Simultaneously, the spindle 1 has axial keyways distributed on it, with a depth ranging from 1 / 100 to 1 / 80 of the spindle 1's diameter. This allows the spindle 1 to better engage with the motor rotor 10, preventing unnecessary displacement during use and avoiding vibration or resonance caused by relative motion.

[0029] In practical implementation, an adjusting spacer 12 is installed at the front end of the rear cylindrical roller bearing 13 to adjust the preload of the rear cylindrical roller bearing 13. Simultaneously, the rear end of the rear cylindrical roller bearing 13 is pressed and positioned by the first rear inner spacer 18 and the second rear inner spacer 20 to prevent loosening during operation. Furthermore, the second rear inner spacer 20 contacts the front end of the brake disc 31, and the rear end of the brake disc 31 contacts the third rear inner spacer 30. Thus, during use, braking control can be achieved by relying on the intervention of the brake disc 31. Moreover, to accommodate the left and right movement of the hydraulic cylinder piston 25 and to meet the requirements for contact and disengagement between the brake positioning disc 22 and the brake disc 31, the wave spring assembly 21 consists of three spring bodies arranged in parallel, with a pre-compression of 0.5-1.2 mm.

[0030] Furthermore, the rear end cap 17 and the rear bearing housing 14 are fixed together by the first set screw 15 and the second set screw 16, achieving effective double locking. Simultaneously, the friction surface of the brake positioning disc 22 is provided with radial grooves, the width of which is 2 to 3 mm and the depth is 0.3 to 0.5 mm. This facilitates the removal of frictional heat and wear debris, maintains a stable coefficient of friction, and improves the actual braking effect. After installation, the clearance between the piston return pin 26 and the brake positioning disc 22 is 0.01-0.03 mm. Moreover, the surface of the brake disc 31 is coated with a tungsten carbide coating with a thickness of 0.1-0.2 mm, which effectively improves its service life.

[0031] Furthermore, to ensure smooth entry of externally introduced hydraulic fluid into the cylinder cavity for braking control, the cylinder cavity includes a first cylinder piston 25 connected to the piston return pin 26. An upper cylinder seal 24 is fitted onto the upper end of the first cylinder piston 25, and a lower cylinder seal 27 is fitted onto the lower end. This achieves synchronous sealing at both ends. Simultaneously, a cylinder seat 23 is fitted over the first cylinder piston 25. Additionally, a connecting disc 28 is connected to the rear end of the spindle 1 via an auxiliary screw. This allows for effective docking with external drive components or other external equipment.

[0032] The working principle of this utility model is as follows: The brake disc 31 is located inside the lathe spindle and is clamped by the control of the hydraulic cylinder chamber. At the same time, the lathe spindle is positioned and locked by the reset mechanism of the wave spring assembly 21.

[0033] The brake disc 31 is built into the rear end of the lathe spindle. Under the action of hydraulic pressure, the cylinder piston 25 presses the brake positioning disc 22. Under the action of force, the brake positioning disc 22 deforms and fits against the brake disc 31, generating frictional torque to achieve the positioning and locking of the spindle.

[0034] When spindle rotation is required, hydraulic pressure adjustment unloads the pressure in the cylinder chamber. Under the force of the wave spring, the piston return disc 29 and piston return pin 26 are pushed, causing the cylinder piston 25 to return to its original position. The brake disc 31 is then released. At this point, the entire lathe spindle can rotate freely. During operation, the locking and unlocking positioning of the brake disc 31 is precise and flexible, improving spindle machining efficiency and part surface quality.

[0035] Example 1 The front-end bearing assembly includes a first precision angular contact bearing 3, a second precision angular contact bearing 4, and a third precision angular contact bearing 7. The front-end bearing assembly also includes an inner spacer 5 and an outer spacer 6 located between the second precision angular contact bearing 4 and the third precision angular contact bearing 7. The inner spacer 5 contacts the spindle 1, and the outer spacer 6 contacts the housing 9. Furthermore, the thickness difference between the inner spacer 5 and the outer spacer 6 is 0.02 mm.

[0036] Meanwhile, axial keyways are distributed on the spindle 1, and the depth of the axial keyways is 1 / 100 of the spindle diameter. In order to meet the left and right movement displacement requirements of the hydraulic cylinder piston 25 and to meet the requirements for contact and disengagement between the brake positioning disc 22 and the brake disc 31, the wave spring assembly 21 is composed of three spring bodies arranged in parallel, and the pre-compression of the spring bodies is 0.5mm.

[0037] Furthermore, the friction surface of the brake positioning disc 22 is provided with radial grooves, the width of which is 2mm and the depth is 0.3mm. After installation, the clearance between the piston return pin 26 and the brake positioning disc 22 is 0.01mm. Additionally, the surface of the brake disc 31 is coated with a tungsten carbide coating with a thickness of 0.1mm.

[0038] Example 2 During application, to allow for a relatively wide range of rotation, the thickness difference between the inner spacer 5 and the outer spacer 6 is 0.05mm. Simultaneously, the depth of the axial keyways distributed on the mandrel 1 is 1 / 80 of the mandrel 1's diameter, avoiding unnecessary excessive depth in the fit. Furthermore, the wave spring assembly 21 consists of three spring bodies arranged in parallel, with a pre-compression of 1.2mm, providing a wider range of deformation force feedback.

[0039] Furthermore, the friction surface of the brake positioning disc 22 is provided with radial grooves, each 2mm wide and 0.5mm deep. This increases the contact area and improves braking performance. After installation, the clearance between the piston return pin 26 and the brake positioning disc 22 is 0.03mm. Additionally, the surface of the brake disc 31 is coated with a tungsten carbide coating with a thickness of 0.2mm, extending the service life of the brake disc 31.

[0040] Furthermore, the directions or positional relationships described in this utility model are based on the directions or positional relationships shown in the accompanying drawings. They are only for the purpose of facilitating the description of this utility model and simplifying the description, and are not intended to indicate or imply that the device or structure referred to must have a specific orientation, or to operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0041] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A built-in brake-type lathe spindle, comprising a spindle (1), a front end cover (2), a housing (9), a motor rotor (10), a motor stator (11), a rear bearing housing (14), and a rear end cover (17), characterized in that: The front end of the spindle (1) is connected to the front end cover (2) through the front end bearing assembly. The front end cover (2) is fixed to the front end of the housing (9) and contacts the front end of the spindle (1). The front end cover (2) presses the outer ring of the front end bearing assembly, and the locking nut (8) presses the inner ring of the front end bearing assembly. The motor rotor (10) is interference-fitted and sleeved on the outer side of the middle part of the spindle (1), and the motor stator (11) is sleeved on the outer side of the motor rotor (10) and fixed in the housing (9) by heat fitting. The rear bearing housing (14) is fixed to the rear end of the housing (9). A rear cylindrical roller bearing (13) is installed inside the rear bearing housing (14) to support the tail of the spindle (1). The rear bearing housing (14) is connected to a rear end cap (17). It also includes a built-in braking mechanism, which consists of a wave spring seat (19), a cylinder seat (23), a brake positioning disc (22), a brake disc (31), a cylinder piston (25), and a wave spring assembly (21). The brake positioning disc (22) is fixed between the wave spring seat (19) and the cylinder seat (23); the front end of the piston return pin (26) is connected to the piston return disc (29), and the rear end of the piston return pin (26) is connected to the cylinder piston (25). The cylinder piston (25) is equipped with a cylinder cavity; the wave spring assembly (21) is connected to the piston return disc (29). The hydraulically driven cylinder piston (25) pushes the brake positioning disc (22) to form a 360° circumferential friction brake with the brake disc (31). When the hydraulic pressure is unloaded, the wave spring assembly (21) resets the brake positioning disc (22) through the piston reset pin (26).

2. The built-in brake lathe spindle according to claim 1, characterized in that: The front bearing assembly includes a first precision angular contact bearing (3), a second precision angular contact bearing (4), and a third precision angular contact bearing (7); the front bearing assembly also includes an inner spacer (5) and an outer spacer (6) located between the second precision angular contact bearing (4) and the third precision angular contact bearing (7), the inner spacer (5) being in contact with the spindle (1), and the outer spacer (6) being in contact with the housing (9); the thickness difference between the inner spacer (5) and the outer spacer (6) is 0.02 to 0.05 mm.

3. The built-in brake lathe spindle according to claim 1, characterized in that: The motor rotor (10) and the spindle (1) have an interference fit surface. The spindle (1) has axial keyways distributed on it. The depth of the axial keyways is 1 / 100 to 1 / 80 of the spindle (1) diameter.

4. The built-in brake lathe spindle according to claim 1, characterized in that: The front end of the rear cylindrical roller bearing (13) is equipped with an adjusting spacer (12) for adjusting the preload of the rear cylindrical roller bearing (13).

5. The built-in brake lathe spindle according to claim 1, characterized in that: The rear end of the rear cylindrical roller bearing (13) is pressed and positioned by the first rear inner spacer (18) and the second rear inner spacer (20); the second rear inner spacer (20) contacts the front end of the brake disc (31), and the rear end of the brake disc (31) contacts the third rear inner spacer (30).

6. The built-in brake lathe spindle according to claim 1, characterized in that: The wave spring assembly (21) consists of three spring bodies arranged in parallel, and the pre-compression of the spring bodies is 0.5-1.2 mm.

7. The built-in brake lathe spindle according to claim 1, characterized in that: The rear end cap (17) and the rear bearing seat (14) are fixed by the first set screw (15) and the second set screw (16).

8. The built-in brake lathe spindle according to claim 1, characterized in that: The friction surface of the brake positioning disc (22) is provided with radial grooves, the width of which is 2 to 3 mm and the depth is 0.3 to 0.5 mm.

9. The built-in brake lathe spindle according to claim 1, characterized in that: The cylinder cavity includes a first cylinder piston (25) connected to the piston reset pin (26). The upper end of the first cylinder piston (25) is fitted with an upper cylinder seal (24), the lower end of the first cylinder piston (25) is fitted with a lower cylinder seal (27), and a cylinder seat (23) is fitted outside the first cylinder piston (25).

10. The built-in brake lathe spindle according to claim 1, characterized in that: The rear end of the mandrel (1) is connected to a connecting plate (28) by an auxiliary screw.

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