A cradle mechanism

Abstract

The utility model relates to a kind of cradle mechanism, including U type cradle, main cradle main shaft, vice cradle main shaft, main cradle rotary seat and vice cradle rotary seat, main cradle main shaft has two end portions of driving end and non-driving end, main cradle main shaft is installed in main cradle rotary seat by the rotary table bearing close to non-driving end and rear end support bearing close to driving end, locking nut is screwed with on main cradle main shaft, located the side of rear end support bearing away from rotary table bearing thread matching, for the rear end support bearing press-fit in place.The utility model U type cradle uses U shape structure design, compatible milling electric spindle and tool holder, shorten tool switching path, improve processing efficiency, main cradle main shaft is installed using high-rigidity rotary table bearing, realize high-rigidity processing, vice cradle main shaft uses conic hole cylindrical roller bearing, cooperate locking nut and adjusting washer use, can realize axial position adjustment and radial rigidity adjustment, facilitate to realize high-precision synchronous rotation.

Description

Technical Field

[0001] This utility model relates to the field of milling and turning technology, specifically a cradle mechanism. Background Technology

[0002] Turning and milling is a composite machining technology that integrates turning and milling processes. With the help of multi-axis CNC equipment or composite machining centers, the rotation of the spindle (turning) and the rotation of the tool (milling) are linked together to complete multiple processes such as turning, milling, drilling, and tapping of parts in a single setup. It can efficiently handle parts with complex rotating surfaces, planes, grooves, cavities and other structures, significantly reduce clamping errors and process turnover, and improve machining accuracy and production efficiency. It is widely used in aerospace, automobile manufacturing, precision machinery and other fields with high requirements for the complexity and precision of parts.

[0003] The cradle structure is a core component of a five-axis machine tool, used to support the workpiece and enable multi-angle rotary machining. Traditional cradle mechanisms have two major technical problems:

[0004] Conventional cradles use a single deep groove ball bearing to support the spindle. During milling, the spindle is prone to flexing vibration due to cutting force, which affects the surface finish. The amplitude of the vibration is aggravated, especially during high torque milling, which leads to tool wear and dimensional deviations.

[0005] Milling and turning machining requires precise and synchronized rotation of the main and auxiliary cradles. However, due to accumulated bearing clearance and asynchronous drive, the existing mechanism has a large deviation in the rotation angle of the two spindles, resulting in tool marks when the turning and milling processes are connected, which requires secondary repair. Utility Model Content

[0006] The purpose of this invention is to provide a cradle mechanism that effectively solves the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution.

[0008] A cradle mechanism includes a U-shaped cradle, a main cradle spindle, a secondary cradle spindle, a main cradle swivel, and a secondary cradle swivel. The main cradle spindle has two ends: a driving end and a non-driving end. The main cradle spindle is mounted in the main cradle swivel via a turntable bearing near the non-driving end and a rear support bearing near the driving end. A locking nut is threaded onto the side of the rear support bearing opposite to the turntable bearing on the main cradle spindle to press the rear support bearing into place. The driving end of the main cradle spindle is connected to a drive mechanism located on the side of the main cradle swivel. The secondary cradle spindle is mounted in the secondary cradle swivel via two sets of tapered roller bearings. A hydraulic brake disc is provided at the end of the secondary cradle spindle away from the main cradle spindle. The two ends of the U-shaped cradle are fixedly connected to the extended ends of the main cradle spindle and the secondary cradle spindle, respectively. The axial position of the U-shaped cradle fixedly connected to the main cradle spindle is adjusted by a washer.

[0009] Furthermore, the inner ring of the tapered bore cylindrical roller bearing mates with the tapered surface of the auxiliary cradle main shaft. Locking nuts and adjusting washers are respectively provided on both sides of the tapered bore cylindrical roller bearing on the auxiliary cradle main shaft to adjust the preload and axial position of the tapered bore cylindrical roller bearing.

[0010] Furthermore, the drive mechanism includes a servo motor and a planetary reducer, which are mounted on the side of the main cradle swivel. The servo motor is connected to the drive end of the main cradle spindle via the planetary reducer.

[0011] Furthermore, the input end of the planetary reducer is directly connected to the output shaft of the servo motor, and the output end is fixed to the main cradle spindle via a keyway.

[0012] Furthermore, an angle grating is installed on the non-drive end of the main cradle spindle for real-time detection of the swing angle.

[0013] Furthermore, the side wall of the U-shaped cradle is provided with a milling electric spindle mounting position and a turning tool holder mounting position, and the two are located on the same machining plane.

[0014] Furthermore, the brake pads of the hydraulic brake disc are connected to the flange of the auxiliary cradle main shaft, and the brake oil circuit is integrated inside the auxiliary cradle rotary seat.

[0015] The outer ring of the turntable bearing is locked and fixed to the main cradle rotary seat screw, and the inner ring is locked and fixed to the main cradle spindle screw.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows.

[0017] The U-shaped cradle adopts a U-shaped structure design, compatible with milling electric spindles and turning tool holders, shortening the tool switching path and improving machining efficiency. The main cradle spindle is mounted with high-rigidity rotary table bearings to achieve high-rigidity machining. The auxiliary cradle spindle uses tapered bore cylindrical roller bearings, used with lock nuts and adjusting washers, to achieve axial position adjustment and radial rigidity adjustment, facilitating high-precision synchronous rotation. In addition, the main cradle spindle is equipped with an angle grating to achieve high-precision oscillation, effectively improving machining accuracy.

[0018] The tapered bore cylindrical roller bearings are pre-tightened with adjusting washers to eliminate clearance, ensuring a high degree of coaxiality between the main cradle spindle and the auxiliary cradle spindle. Combined with the hydraulic brake disc, the position of the auxiliary cradle spindle can be locked in a short time, effectively controlling the angle error during milling and turning. In addition, the main cradle spindle uses a servo motor to drive the U-shaped cradle to swing through a high-precision planetary reducer, which facilitates high-torque swing machining. Attached Figure Description

[0019] Figure 1 This is a three-dimensional schematic diagram of the overall structure of this utility model;

[0020] Figure 2 for Figure 1 A planar schematic diagram of the structure shown;

[0021] Figure 3 for Figure 2 A cross-sectional schematic diagram of the structure shown.

[0022] In the diagram: 1. U-shaped cradle; 2. Main cradle spindle; 21. Turntable bearing; 22. Rear end support bearing; 3. Secondary cradle spindle; 31. Tapered bore cylindrical roller bearing; 32. Locking nut; 33. Adjusting washer; 4. Main cradle slewing seat; 5. Secondary cradle slewing seat; 6. Servo motor; 7. Planetary reducer; 8. Hydraulic brake disc. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] In the description of the embodiments of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection" and "installation" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Furthermore, "connection" can be a direct connection or an indirect connection through an intermediate medium. "Fixed" means that the relative positional relationship remains unchanged after the connection. The directional terms mentioned in the embodiments of this utility model, such as "inner," "outer," "top," and "bottom," are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of this utility model, and are not intended to 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 limitations on the embodiments of this utility model.

[0025] In this embodiment of the invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0026] Please see Figures 1-3 This utility model provides a cradle mechanism, including a U-shaped cradle 1, a main cradle spindle 2, a secondary cradle spindle 3, a main cradle rotary seat 4, and a secondary cradle rotary seat 5. The two ends of the U-shaped cradle 1 are fixedly connected to the extended ends of the main cradle spindle 2 and the secondary cradle spindle 3 respectively through flange structures. The side wall of the U-shaped cradle 1 is machined with a milling electric spindle mounting position (not shown in the figure) and a turning tool holder mounting position (not shown in the figure), and the two are located on the same horizontal plane. In addition, the parallelism between the milling electric spindle mounting position and the turning tool holder mounting position is ≤0.01mm, ensuring that no additional height adjustment is required when switching between milling and turning tools, thus shortening the machining path.

[0027] The main cradle spindle 2 has two ends, a driving end and a non-driving end. The main cradle spindle 2 is installed in the main cradle swivel seat 4 through a turntable bearing 21 near the non-driving end and a rear support bearing 22 near the driving end. A locking nut 32 is threadedly fitted on the side of the main cradle spindle 2 opposite to the turntable bearing 21 of the rear support bearing 22 to press the rear support bearing 22 into place. The turntable bearing 21 is a crossed roller bearing, and its outer ring is clearance-fitted with the main cradle swivel seat 4 with a clearance of 0.005-0.01mm. The inner ring is locked and fixed to the main cradle spindle 2 with screws.

[0028] The U-shaped cradle 1 is fixedly connected to the main cradle spindle 2 at one end, and the center axial position is adjusted by a washer. The drive end of the main cradle spindle 2 is positioned by the rear support bearing 22. The outer side of the rear support bearing 22 is press-fitted with a lock nut 32 to ensure that the main cradle spindle 2 does not move axially.

[0029] The auxiliary cradle main shaft 3 is installed in the auxiliary cradle slewing seat 5 through two sets of tapered bore cylindrical roller bearings 31. The coaxiality error between the main cradle main shaft 2 and the auxiliary cradle main shaft 3 is ≤0.01mm. The inner ring of the tapered bore cylindrical roller bearing 31 is interference-fitted with the auxiliary cradle main shaft 3 with a 1:10 taper surface. Locking nuts 32 and adjusting washers 33 are respectively provided on both sides of the tapered bore cylindrical roller bearings 31 on the auxiliary cradle main shaft 3. The thickness tolerance of the adjusting washers 33 is ≤0.01mm. The bearing preload is adjusted by increasing or decreasing the thickness of the adjusting washers 33. The locking nuts 32 adopt an anti-loosening thread design. After tightening, the bearing clearance is eliminated, so that the coaxiality between the main cradle main shaft 2 and the auxiliary cradle main shaft 3 is ≤0.01mm.

[0030] In addition, the thread accuracy of the locking nut 32 in this application is 6H grade.

[0031] The drive end of the main cradle spindle 2 is connected to the drive mechanism arranged on the side of the main cradle rotary seat 4. The drive mechanism includes a servo motor 6 and a planetary reducer 7. The servo motor 6 and the planetary reducer 7 are fixed to the side of the main cradle rotary seat 4 by bolts. The servo motor 6 is connected to the drive end of the main cradle spindle 2 through the planetary reducer 7. The reduction ratio of the planetary reducer 7 is 1:50, and the input end of the planetary reducer 7 is directly connected to the output shaft of the servo motor 6. The output end is fixed to the main cradle spindle 2 through a keyway to achieve high torque output with a rated torque ≥1000 N·m.

[0032] The end of the secondary cradle spindle 3 away from the main cradle spindle 2 is fixed with a hydraulic brake disc 8 via a flange. The brake pads of the hydraulic brake disc 8 are connected to the flange of the secondary cradle spindle 3, and the brake oil circuit is integrated inside the secondary cradle rotary seat 5. When braking, the oil pressure is ≥3MPa, which can lock the position of the secondary cradle spindle 3 within 0.1 seconds, so as to effectively control the angle error and the machining error caused by the vibration of the cradle during machining.

[0033] Specifically, an angle grating (not shown in the figure) is installed on the non-drive end of the main cradle spindle 2. The angle grating has a resolution of 0.001° and is used to detect the swing angle in real time so as to feed back to the CNC system to realize closed-loop control.

[0034] The specific working principle of this application is as follows:

[0035] When it is necessary to switch from turning to milling, the servo motor 6 drives the main cradle spindle 2 to swing through the planetary reducer 7. The angle grating provides real-time feedback on the swing angle. After the U-shaped cradle 1 is adjusted to the target angle, the hydraulic brake disc 8 starts to lock the position of the auxiliary cradle spindle 3. At this time, the milling electric spindle and the tool holder switch to the same machining plane to achieve seamless connection of processes.

[0036] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A cradle mechanism, characterized in that: It includes a U-shaped cradle (1), a main cradle spindle (2), a secondary cradle spindle (3), a main cradle swivel seat (4), and a secondary cradle swivel seat (5). The main cradle spindle (2) has two ends, a driving end and a non-driving end. The main cradle spindle (2) is installed in the main cradle rotary seat (4) through a turntable bearing (21) near the non-driving end and a rear support bearing (22) near the driving end. A locking nut (32) is threadedly fitted on the main shaft (2) of the main cradle on the side opposite to the turntable bearing (21) of the rear support bearing (22) to press the rear support bearing (22) into place. The drive end of the main shaft (2) of the main cradle is connected to the drive mechanism arranged on the side of the main cradle rotary seat (4); The auxiliary cradle main shaft (3) is installed in the auxiliary cradle slewing seat (5) through two sets of tapered bore cylindrical roller bearings (31). The auxiliary cradle main shaft (3) is provided with a hydraulic brake disc (8) at the end away from the main cradle main shaft (2). The two ends of the U-shaped cradle (1) are respectively fixedly connected to the extended ends of the main cradle spindle (2) and the auxiliary cradle spindle (3); The U-shaped cradle (1) is fixedly connected to the main shaft (2) of the main cradle at one end, and the central axial position is adjusted by a washer.

2. The cradle mechanism according to claim 1, characterized in that: The inner ring of the tapered bore cylindrical roller bearing (31) is fitted with the tapered surface of the auxiliary cradle main shaft (3); On the secondary cradle main shaft (3), lock nuts (32) and adjusting washers (33) are respectively provided on both sides of the tapered bore cylindrical roller bearing (31) to adjust the preload and axial position of the tapered bore cylindrical roller bearing (31).

3. The cradle mechanism according to claim 1, characterized in that: The drive mechanism includes a servo motor (6) and a planetary reducer (7); The servo motor (6) and the planetary reducer (7) are installed on the side of the main cradle swivel (4), and the servo motor (6) is connected to the drive end of the main cradle spindle (2) through the planetary reducer (7).

4. A cradle mechanism according to claim 3, characterized in that: The input end of the planetary reducer (7) is directly connected to the output shaft of the servo motor (6), and the output end is fixed to the main shaft (2) of the main cradle through a keyway.

5. A cradle mechanism according to claim 1, characterized in that: An angle grating is installed on the non-drive end of the main cradle spindle (2) for real-time detection of the swing angle.

6. A cradle mechanism according to claim 1, characterized in that: The side wall of the U-shaped cradle (1) is provided with a milling electric spindle mounting position and a turning tool holder mounting position, and the two are located on the same machining plane.

7. A cradle mechanism according to claim 1, characterized in that: The brake pads of the hydraulic brake disc (8) are connected to the flange of the auxiliary cradle main shaft (3), and the brake oil circuit is integrated inside the auxiliary cradle rotary seat (5).

8. A cradle mechanism according to claim 1, characterized in that: The outer ring of the turntable bearing (21) is screwed and fixed to the main cradle swivel seat (4), and the inner ring is screwed and fixed to the main cradle spindle (2).

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