A CNC lathe spindle bearing pre-tightening force adjusting mechanism

Abstract

The utility model discloses a numerical control lathe main shaft bearing pre -tightening force adjusting mechanism, including bearing seat and pre -tightening disc. The utility model discloses through adopting fixed electromagnet, moving electromagnet, pressure sensor, through the current intensity and the current direction that the fixed electromagnet and moving electromagnet in the fixed disc inside of different positions exert to control, the suction force and repulsion that two groups of electromagnets produce will happen corresponding change, thereby make the interval between two groups of pre -tightening disc change, make the pre -tightening force that bearing exerts change, simultaneously when moving electromagnet moves up and down, the pressure that the pressure sensor is transferred to with the pressure column of bottom also will happen corresponding change, the pressure change that pressure sensor detects subsequently can judge the pre -tightening force change that adds to the bearing at main shaft, and then timely to the pre -tightening force is adjusted, has the advantage that regulation and control timely, the regulating accuracy is high, the operation is laborsaving.

Description

Technical Field

[0001] This utility model relates to the field of electric spindle technology, specifically to a preload adjustment mechanism for CNC lathe spindle bearings. Background Technology

[0002] The electric spindle is one of the core components of a machine tool, widely used in machinery and PCB manufacturing. In existing electric spindle assemblies, a bearing is added to the rear end of the spindle to support it and ensure balanced operation. During operation, the electric spindle exerts axial impact force on the bearing. To ensure the spindle can operate stably at high speed with the bearing's support, a preload is required to guarantee its service life.

[0003] The existing publicly available technology, application number CN202223052438.3, discloses an adjustable bearing preload structure for an electric spindle. This structure involves installing a set screw within a countersunk hole. By engaging the set screw, the height of a spring within the countersunk hole is adjusted, thereby regulating the preload force exerted by the spring reaction on the spring seat. This allows for flexible adjustment of the preload force of the spring seat on the bearing, reducing wear on both the electric spindle and the bearing, and effectively extending the service life of the electric spindle. However, the above-mentioned patent still has certain drawbacks in use: it adjusts the height of the spring in the countersunk hole by tightening the set screw, which is used to adjust the preload force of the spring reaction on the spring seat. However, the precision control that can be achieved in this way is not ideal, which affects the running quality of the spindle. At the same time, the preload force cannot be adjusted in time, and manual processing is required every time, which delays the operation of the spindle. The overall use effect is not ideal.

[0004] There are currently no effective solutions to the problems in the relevant technologies. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a preload adjustment mechanism for CNC lathe spindle bearings, which has the advantages of timely adjustment, high adjustment accuracy, and labor-saving operation, thereby solving the problems mentioned in the background technology.

[0006] To achieve the advantages of timely regulation, high adjustment accuracy, and labor-saving operation, the specific technical solution adopted by this utility model is as follows: A preload adjustment mechanism for a CNC lathe spindle bearing includes a bearing housing and a preload plate. A bearing is installed inside the bearing housing, and a spindle is connected to the surface of the bearing. Fixed plates are symmetrically installed at both ends of the bearing inside the bearing housing. Several sets of fixed electromagnets are evenly arranged around the bottom of the fixed plates. A movable electromagnet is installed above the fixed electromagnets. A preload column is fixedly installed at one end of each movable electromagnet. One end of the preload column passes through one side of the fixed plate and connects to the preload plate. The preload plate contacts the bearing surface. A spring is sleeved around the outer periphery of the preload column inside the fixed plate, and both ends of the spring are fixed to the inner wall of the fixed plate and the surface of the movable electromagnet, respectively.

[0007] Furthermore, an insulating sleeve is installed at the top center of the fixed electromagnet, and a pressure sensor is installed inside the insulating sleeve.

[0008] Furthermore, a pressure column is fixedly installed at the middle position of the bottom of the movable electromagnet.

[0009] Furthermore, the pressure column is located directly above the pressure sensor and is slidably connected to the inner wall of the insulating sleeve.

[0010] Furthermore, the fixed electromagnet, the movable electromagnet, and the pressure sensor are all electrically connected to the control box via wires.

[0011] Furthermore, several sets of sliders are mounted around the surface of the movable electromagnet.

[0012] Furthermore, several sets of sliding grooves are formed around the inner surface of the fixed disk.

[0013] Furthermore, the slider is slidably connected to the groove.

[0014] Compared with the prior art, this utility model provides a preload adjustment mechanism for CNC lathe spindle bearings, which has the following advantages: This invention employs a fixed electromagnet, a movable electromagnet, and a pressure sensor. By controlling the current intensity and direction applied to the fixed and movable electromagnets inside the fixed plate at different positions, the attractive and repulsive forces generated between the two sets of electromagnets change accordingly. This causes a corresponding change in the distance between the two sets of preload plates, which in turn changes the preload force applied to the bearing in the middle position. Simultaneously, when the movable electromagnet moves up and down, the pressure transmitted to the pressure sensor by the pressure column at its bottom also changes accordingly. The pressure change detected by the pressure sensor indicates the change in the preload force applied to the bearing at the spindle. By adjusting the state of multiple sets of electromagnets based on the pressure value, the preload force can be adjusted in a timely manner, ensuring efficient spindle operation. It has the advantages of timely control, high adjustment accuracy, and labor-saving operation. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a CNC lathe spindle bearing preload adjustment mechanism proposed in this utility model; Figure 2 This is a schematic diagram of the structure of the movable electromagnet of this utility model; Figure 3 This is a schematic diagram of the structure of the fixing plate of this utility model; Figure 4 This is a schematic diagram of the pre-tightening disc of this utility model.

[0017] In the picture: 1. Bearing housing; 2. Slider; 3. Control box; 4. Spring; 5. Pressure sensor; 6. Preload plate; 7. Moving electromagnet; 8. Pressure column; 9. Bearing; 10. Fixed plate; 11. Preload column; 12. Spindle; 13. Insulating sleeve; 14. Fixed electromagnet; 15. Slide groove. Detailed Implementation

[0018] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are usually used to represent similar components.

[0019] According to an embodiment of the present invention, a preload adjustment mechanism for CNC lathe spindle bearings is provided.

[0020] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, such as... Figure 1-4As shown, a CNC lathe spindle bearing preload adjustment mechanism according to an embodiment of the present invention includes a bearing housing 1 and a preload plate 6. A bearing 9 is installed inside the bearing housing 1, and a spindle 12 is connected to the surface of the bearing 9. Fixed plates 10 are symmetrically installed at both ends of the bearing 9 within the bearing housing 1. Several sets of fixed electromagnets 14 are evenly arranged around the bottom of the fixed plates 10. A movable electromagnet 7 is installed above the fixed electromagnets 14. A preload column 11 is fixedly installed at one end of the movable electromagnet 7. One end of the preload column 11 passes through one side of the fixed plate 10 and connects to the preload plate 6. The preload plate 6 contacts the surface of the bearing 9, and the outer periphery of the preload column 11 is located inside the fixed plate 10. A spring 4 is fitted, with its two ends fixed to the inner wall of the fixed plate 10 and the surface of the movable electromagnet 7, respectively. Bearing housing 1 serves as the basic support structure, with an internal mounting cavity for mounting bearing 9 via an interference fit. The inner ring of bearing 9 rotates synchronously with the main shaft 12 via a key connection or interference fit. Fixed plate 10 is symmetrically mounted inside the bearing housing 1 at both ends of bearing 9 and fixed to the bearing housing 1 via circumferential bolts. A through hole is formed in the center of the fixed plate 10 for the preload column 11 to pass through, and electromagnet mounting grooves are evenly spaced around its edges for fixing the fixed electromagnet 14. Movable electromagnet 7 is located directly above the fixed electromagnet 14, forming a vertically aligned electromagnetic system with the fixed electromagnet 14. Coupling structure; the pre-tightening column 11 is fixed to the side of the movable electromagnet 7 by bolts. After the pre-tightening column 11 passes through the through hole of the fixed plate 10, its end is fixed to the pre-tightening plate 6 by thread or welding. The pre-tightening plate 6 is a ring structure, with the inner ring tightly fitting the end face of the outer ring of the bearing 9, for directly applying pre-tightening force; Spring 4: sleeved on the outer circumference of the pre-tightening column 11, one end is fixed to the spring seat 4 on the inner wall of the fixed plate 10 by snap ring or welding, and the other end abuts against the bottom surface of the movable electromagnet 7 to form elastic support; Structural cooperation and functional role, pre-tightening force adjustment principle: by controlling the direction and intensity of the current of the fixed electromagnet 14 and the movable electromagnet 7, the electromagnetic force (attraction or repulsion) between the two is changed; for example: when the current... When the current flows in the same direction, the two electromagnets generate a repulsive force, pushing the moving electromagnet 7 away from the fixed plate 10. This, through the pre-tightening column 11, drives the pre-tightening plate 6 towards the bearing 9, compressing the spring 4 and increasing the pre-tightening force. When the current flows in opposite directions, an attractive force is generated, causing the moving electromagnet 7 to approach the fixed plate 10. The spring 4 then resets, reducing the pre-tightening force. During this process, the spring 4 acts as a buffer and balance for the electromagnetic force, preventing rigid impacts and providing a certain pre-tightening force reference. Mechanical stability: The fixation of the fixed plate 10 to the bearing seat 1 ensures the support rigidity of the entire adjustment mechanism. The clearance fit between the pre-tightening column 11 and the through hole of the fixed plate 10 ensures the accuracy of the movement guide and prevents deviation when the pre-tightening force is applied.

[0021] In one embodiment, an insulating sleeve 13 is installed at the top center of the fixed electromagnet 14, and a pressure sensor 5 is installed inside the insulating sleeve 13. The insulating sleeve 13 is made of insulating materials such as epoxy resin or ceramic and is fixed to the center of the top surface of the fixed electromagnet 14 by adhesive. A cylindrical cavity is formed inside the insulating sleeve 13 to accommodate the pressure sensor 5, and the bottom surface of the sensor is fixed to the insulating sleeve 13. Functional purpose: Electrical isolation: The insulating sleeve 13 isolates the high-voltage area of ​​the fixed electromagnet 14 from the low-voltage signal area of ​​the pressure sensor 5 to avoid electromagnetic interference affecting the accuracy of the sensor. Pressure transmission: The top surface of the pressure sensor 5 directly bears the axial pressure of the pressure column 8, and converts the mechanical pressure into an electrical signal through strain gauges or piezoresistive effect to provide real-time feedback of the preload value.

[0022] In one embodiment, a pressure column 8 is fixedly installed at the bottom center of the movable electromagnet 7. The pressure column 8 is a cylindrical metal rod, with its bottom end fixed to the center of the bottom surface of the movable electromagnet 7 by thread or welding, and its top end is a flat structure facing the top surface of the pressure sensor 5. The inner wall of the insulating sleeve 13 has a sliding groove that matches the outer diameter of the pressure column 8, ensuring that the pressure column 8 moves only along the axial direction and avoiding radial shaking that could cause pressure measurement errors.

[0023] In one embodiment, the pressure column 8 is located directly above the pressure sensor 5 and is slidably connected to the inner wall of the insulating sleeve 13. When the movable electromagnet 7 moves up and down, the pressure column 8 moves synchronously, and its top end applies or releases pressure to the pressure sensor 5. The sensor transmits the pressure signal to the control box 3. The control box 3 automatically adjusts the electromagnet current through a preset threshold to form a "detection-adjustment" closed loop, thereby achieving dynamic and precise control of the preload.

[0024] In one embodiment, the fixed electromagnet 14, the movable electromagnet 7, and the pressure sensor 5 are all electrically connected to the control box 3 via wires. The control box 3 is connected to the fixed electromagnet 14, the movable electromagnet 7, and the pressure sensor 5 via multi-core shielded cables. For the electromagnets, it outputs an adjustable current, controls the current intensity using PWM (Pulse Width Modulation) technology, and switches the current direction via a relay. For the pressure sensor 5, it receives analog or digital signals and uses a built-in microprocessor (such as a PLC or microcontroller) for data processing and control logic operations. Functionally, it provides automated adjustment: the control box 3 automatically adjusts the electromagnetic force of the electromagnets based on the real-time preload data fed back by the pressure sensor 5, without manual intervention, achieving a rapid response of "real-time monitoring - real-time adjustment". Parameter preset: it supports presetting the preload range via a human-machine interface (such as a touch screen), and automatically alarms and triggers adjustment actions when the actual pressure exceeds the threshold.

[0025] In one embodiment, a number of sliders 2 are mounted around the surface of the movable electromagnet 7. The sliders 2 are typically made of copper alloy or engineering plastic and are uniformly fixed to the outer periphery of the movable electromagnet 7 by screws.

[0026] In one embodiment, a plurality of sliding grooves 15 are provided around the inner surface of the fixed disk 10. The sliding grooves 15 are T-shaped or dovetail-shaped grooves formed on the inner wall of the fixed disk 10, and form a sliding pair with the slider 2.

[0027] In one embodiment, the slider 2 is slidably connected to the slide groove 15, providing anti-deflection guidance: the cooperation between the slider 2 and the slide groove 15 restricts the circumferential rotation and radial offset of the moving electromagnet 7, ensuring that the preload column 11 moves only along the axis of the main shaft 12, ensuring that the preload is evenly applied to the end face of the bearing 9, and avoiding abnormal wear of the bearing 9 due to uneven load; low-friction movement: the sliding pair surface can be coated with a molybdenum disulfide lubricating layer or a linear bearing 9 can be installed to reduce movement resistance, improve adjustment sensitivity and mechanism life; overall coordinated workflow, preload initialization: the control box 3 applies an initial current to the fixed electromagnet 14 and the moving electromagnet 7, and through the combined action of electromagnetic force and spring 4, the preload disc 6 applies a set initial preload to the bearing 9, and the pressure sensor 5 provides feedback on the initial pressure value; dynamic adjustment: when the preload of the bearing 9 fluctuates due to load changes during the operation of the main shaft 12, the pressure sensor 5 provides real-time feedback. Pressure changes are detected and transmitted to control box 3. Control box 3 calculates the required electromagnetic force through an algorithm, adjusts the electromagnet current, drives the moving electromagnet 7 to move, and corrects the preload in real time through preload column 11 and preload disc 6. Stable maintenance: Spring 4 and electromagnetic force form a dynamic balance, slider 2 and slide groove 15 ensure movement accuracy, and pressure sensor 5 and control box 3 form a closed-loop feedback, ultimately achieving high-precision and stable control of preload. Technical effect summary: Timely adjustment: The closed-loop control system has a fast response speed and can complete preload detection and adjustment in milliseconds, adapting to the real-time needs of high-speed operation of spindle 12. High adjustment accuracy: Precise control of preload is achieved through the continuous adjustability of electromagnetic force and the high-precision detection of pressure sensor 5. Labor-saving operation: The all-electric control requires no manual intervention, avoiding the tedious operation and human error of traditional manual adjustment (such as tightening screws), and reducing labor intensity.

[0028] Working Principle: In actual use, when it is necessary to adjust the preload of the spindle bearing, the current intensity and direction applied to the fixed electromagnets and moving electromagnets inside the fixed plates at different positions can be controlled. At this time, the attraction and repulsion forces generated between the two sets of electromagnets will change accordingly, thereby changing the distance between the two sets of preload plates. This, in turn, changes the preload applied to the bearing in the middle position. At the same time, when the moving electromagnet moves up and down, the pressure transmitted to the pressure sensor by the pressure column at its bottom will also change accordingly. The pressure change detected by the pressure sensor can determine the change in the preload applied to the bearing at the spindle. Then, the state of multiple sets of electromagnets can be adjusted according to the pressure value, thereby adjusting the preload in a timely manner and ensuring the high efficiency of spindle operation. The entire adjustment process does not require much human intervention, thus effectively ensuring the timeliness and accuracy of control, while reducing the labor intensity of personnel and facilitating better use. The device as a whole has the advantages of timely control, high adjustment accuracy, and labor-saving operation.

[0029] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "setting", "connection", "fixing", "screw connection", etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0030] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A preload adjustment mechanism for a CNC lathe spindle bearing, comprising a bearing housing (1) and a preload disc (6), characterized in that, The bearing housing (1) is equipped with a bearing (9), and a spindle (12) is connected to the surface of the bearing (9). Fixed disks (10) are symmetrically installed at both ends of the bearing (9) inside the bearing housing (1). Several sets of fixed electromagnets (14) are evenly installed around the bottom of the fixed disk (10). A movable electromagnet (7) is installed above the fixed electromagnet (14). A pre-tightening column (11) is fixedly installed at one end of the movable electromagnet (7). One end of the pre-tightening column (11) passes through one side of the fixed disk (10) and is connected to the pre-tightening disk (6). The pre-tightening disk (6) is in contact with the surface of the bearing (9). A spring (4) is sleeved on the outer periphery of the pre-tightening column (11) inside the fixed disk (10), and the two ends of the spring (4) are fixed to the inner wall of the fixed disk (10) and the surface of the movable electromagnet (7), respectively.

2. The preload adjustment mechanism for CNC lathe spindle bearings according to claim 1, characterized in that, An insulating sleeve (13) is installed at the top center of the fixed electromagnet (14), and a pressure sensor (5) is installed inside the insulating sleeve (13).

3. The preload adjustment mechanism for CNC lathe spindle bearings according to claim 1, characterized in that, A pressure column (8) is fixedly installed at the middle position of the bottom of the movable electromagnet (7).

4. The preload adjustment mechanism for CNC lathe spindle bearings according to claim 3, characterized in that, The pressure column (8) is located directly above the pressure sensor (5) and is slidably connected to the inner wall of the insulating sleeve (13).

5. The preload adjustment mechanism for the spindle bearing of a CNC lathe according to claim 1, characterized in that, The fixed electromagnet (14), the movable electromagnet (7), and the pressure sensor (5) are all electrically connected to the control box (3) via wires.

6. The preload adjustment mechanism for CNC lathe spindle bearings according to claim 1, characterized in that, The movable electromagnet (7) has several sets of sliders (2) mounted around its surface.

7. The preload adjustment mechanism for CNC lathe spindle bearings according to claim 1, characterized in that, The fixed disk (10) has several sets of sliding grooves (15) arranged around its inner surface.

8. A preload adjustment mechanism for a CNC lathe spindle bearing according to claim 6, characterized in that, The slider (2) is slidably connected to the groove (15).

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