High speed circular saw machine for machining bearing forgings

Abstract

The application belongs to the technical field of metal cutting processing, and discloses a high-speed circular sawing machine for bearing forging machining, which comprises a bed body, a workbench, an operating arm, a circular saw blade, a feeding unit and a control system, and the key lies in that a passive constraint type damping vibration suppression system is additionally arranged; the system comprises left and right damping rings which are symmetrically arranged on the two sides of the cutting area of the circular saw blade, are installed on the operating arm through a follow-up arm, and keep a uniform air gap of 0.05-0.5 mm with the side surface of the saw blade; an oil groove filled with semi-solid damping grease is arranged on the inner end surface of the damping ring and is coated with an elastic self-lubricating coating, and a positive pressure air curtain generating device is arranged on the periphery; the control system drives the damping ring to rotate at a differential speed relative to the saw blade during sawing, continuously coats the damping grease on the surface of the saw blade to form an extrusion oil film. The non-contact extrusion oil film damping effect effectively suppresses the transverse sawing chatter, significantly improves the sawing surface quality and the service life of the saw blade, simultaneously realizes clean lubrication, and is suitable for high-speed and precise blanking of bearing steel bars.

Description

Technical Field

[0001] This invention relates to the field of metal cutting equipment technology, and in particular to a high-speed circular saw for processing bearing forgings. Background Technology

[0002] In the bearing manufacturing industry, the quality of the blank cutting before the forging process directly affects the forming accuracy, material utilization rate, and production cost of subsequent forgings. Bearing steel (such as GCr15) is a high-carbon chromium bearing steel, characterized by high hardness (approximately HB179-207 in the annealed state), good wear resistance, but poor machinability, and is also expensive.

[0003] High-speed circular saws have become the mainstream equipment for precision cutting of bearing steel bars due to their high cutting efficiency, narrow kerf, and low material loss. Their working principle involves using a thin circular saw blade (typically ≤2.5mm thick) and achieving feed sawing through the swinging of the operating arm. However, the following prominent technical defects exist in actual production: Severe sawing chatter: When the saw blade cuts into the bar stock at 1 / 3 to 2 / 3 of its diameter, the radial cutting force changes abruptly. Combined with the low transverse stiffness of the thin saw blade, this easily induces transverse chatter. Chatter not only deteriorates the quality of the saw cut surface (surface roughness Ra≥6.3μm, far exceeding the subsequent finishing requirement of Ra≤3.2μm), but also accelerates saw tooth breakage and fatigue cracking of the saw blade.

[0004] Short saw blade lifespan: Under continuous chattering conditions, circular saw blades are subjected to unsteady alternating stress, causing fatigue and chipping of the saw teeth. The actual lifespan of a saw blade is usually only 30,000 to 50,000 cuts. Frequent replacement of saw blades leads to low overall equipment efficiency and increases tool costs.

[0005] Cutting fluid / lubricant waste and pollution: Traditional external spray lubrication methods are difficult to effectively enter narrow cuts, and a large amount of cutting fluid is thrown out at high speed, causing the workshop environment to be dirty and detrimental to environmental protection.

[0006] While existing technologies include adding rigid guide plates or pressure blocks to the side of the saw blade to suppress vibration, such contact constraints exacerbate saw blade friction and wear, and may even cause jamming due to embedded chips. Non-contact air-float or magnetic-float damping devices are complex in structure, expensive, and difficult to adapt to saw blade oscillation conditions. Summary of the Invention

[0007] To overcome the technical defects of existing technologies, this invention provides a high-speed circular saw for processing bearing forgings, comprising a bed, a worktable mounted on the bed, an operating arm mounted above the worktable, a circular saw blade mounted on the operating arm, a feed unit for driving the operating arm to swing, a clamping unit for clamping bar stock, an automatic feeding unit, and a control system; it also includes a passive constraint damping vibration suppression system, which comprises: The left damping ring and the right damping ring are symmetrically arranged on both sides of the cutting area of ​​the circular saw blade, which is the part where the circular saw blade contacts the bar stock and cuts it. The cutting section of the circular saw blade passes between the left damping ring and the right damping ring. The left and right damping rings are mounted on the frame of the operating arm via a swingable follower arm, the swing axis of which is parallel or coincident with the swing axis of the operating arm; a uniform annular air gap of 0.05-0.5mm is maintained between the inner end face of the left and right damping rings facing the circular saw blade and the corresponding side face of the circular saw blade; multiple oil grooves are formed on the inner end face of the left and right damping rings, and the oil grooves are filled with damping medium; the inner end face surfaces of the left and right damping rings are coated with an elastic self-lubricating coating with a thickness of 0.1-0.3mm; It also includes a positive pressure air curtain generator set around the left and right damping rings. The positive pressure air curtain generator is equipped with multiple micro nozzles that spray compressed air into the air gap inlet to form an annular air curtain around the air gap. The control system is configured to: during the sawing process, cause the left damping ring and the right damping ring to rotate relative to the circular saw blade, thereby creating a differential speed between the left damping ring and the right damping ring and the circular saw blade, and continuously apply the damping medium to the surface of the circular saw blade.

[0008] Preferably, the damping medium is a semi-solid damping grease with a cone penetration of 250-300 at 25°C and a dropping point ≥180°C; the oil groove 11 is one of a spiral groove, a radial straight groove, and a mesh groove, with a groove depth of 0.1-1.0 mm and a groove width of 0.5-2.0 mm; a spiral chip removal groove is also provided on the outer side of the inner end face of the damping ring, the spiral chip removal groove having a depth of 0.3-0.5 mm, a spiral angle greater than 60°, and a spiral direction set to throw the chips entering the air gap away from the circular saw blade when the damping ring rotates.

[0009] Preferably, the left and right damping rings are mounted on the follower arm via rolling bearings. The rotational motion is passively driven by the viscous shear force generated by the damping grease in the air gap when the circular saw blade rotates, so that the rotational speed of the left and right damping rings is 1%-10% of the rotational speed of the circular saw blade and the rotational direction is the same. The rolling bearings are angular contact ball bearings with a precision of P4 or higher and are subject to a light preload. The outer diameter of the damping ring is 0.4-0.7 times the diameter of the circular saw blade, and the axial width of the damping ring is 5-20 mm.

[0010] Preferably, it also includes an independent drive device, which includes a servo motor, a reducer and a transmission mechanism. The servo motor is fixed to the follower arm by a motor mount, and the transmission mechanism is at least one of the following: a gear transmission mechanism, a synchronous belt transmission mechanism, and a friction wheel transmission mechanism. The independent drive device is used to independently control the speed and direction of rotation of the left damping ring and the right damping ring.

[0011] Preferably, the axial positions of the left and right damping rings can be adjusted independently; each left and right damping ring is provided with an air gap adjustment structure between itself and the corresponding follower arm. The adjustment structure includes a horizontal guide rail on the operating arm, a sliding block on the horizontal guide rail for moving the horizontal guide rail, and the sliding block is fixed to the follower arm. The horizontal guide rail is also provided with a linear drive mechanism for driving the sliding block 7 to make precise movements.

[0012] Preferably, the control system is further configured to perform the following multiple operating modes: Pre-wetting mode: Before sawing begins and after the circular saw blade has rotated, drive the left and right damping rings to rotate unidirectionally or oscillate back and forth at a speed of 5-30 rpm for 1-5 seconds. Enhanced damping mode in the cutting area: When the circular saw blade cuts into the bar stock 6 in the range of 1 / 3 to 2 / 3 of the diameter, the left and right damping rings are driven to rotate in the opposite direction to the circular saw blade at a speed of 20-100 rpm. Dynamic air gap adjustment mode: During normal sawing, the air gap is maintained at 0.05-0.2mm; when the vibration sensor detects a high-frequency impact signal, the control system instantly pushes the left and right damping rings axially apart through the linear drive mechanism, causing the air gap to increase briefly to 0.5mm and start the positive pressure air curtain to blow away the chips, and then returns to the normal air gap. Post-immersion mode: After sawing is completed and before the circular saw blade stops swinging, drive the left and right damping rings to continue rotating at a speed of 5-20 rpm for 5-15 seconds.

[0013] Preferably, it also includes a vibration sensing and collision warning component, which includes: At least one vibration sensor is mounted on the follower arm or manipulator arm to detect the lateral vibration amplitude, frequency and acceleration of the circular saw blade in real time. The gap monitoring sensor, which is one of the following two types of sensors: capacitive displacement sensor or laser displacement sensor, is installed on the follower arm and is used to measure the instantaneous distance between the circular saw blade and the inner end faces of the left and right damping rings in real time. The control system includes a controller that immediately performs at least one of the following operations when the gap monitoring sensor detects a distance less than 0.03 mm or the vibration sensor detects an amplitude exceeding 0.4 mm: emergency tool retraction, reducing feed speed, or stopping spindle rotation. The controller also uses an adaptive algorithm to dynamically adjust the output speed of the independent drive device based on the feedback signal of the vibration sensor, so that the differential speed between the left and right damping rings and the circular saw blade matches the current flutter state in real time; when the detected vibration acceleration exceeds 0.5g, the controller immediately performs at least one of the following two operations: switching the rotation direction of the damping ring to the reverse direction, or increasing the differential speed to 80%-100% of the preset maximum value.

[0014] Preferably, the left and right damping rings are made of a copper alloy with a thermal conductivity ≥100 W / (m·K); the elastic self-lubricating coating is a polyimide-based composite coating, wherein 5%-15% by mass of a solid lubricant is added, and the solid lubricant is at least one of the following two substances: molybdenum disulfide and graphite.

[0015] Preferably, it includes the following steps: Equipment start-up and pre-wetting steps: Start the spindle motor to rotate the circular saw blade, and at the same time start the positive pressure air curtain generator to drive the left and right damping rings to rotate relative to the circular saw blade. The semi-solid damping grease is applied to both sides of the circular saw blade through the oil groove on the inner end face of the damping ring to form a damping grease film with a thickness of 0.05-0.5mm. This pre-wetting process lasts for 1-5 seconds. Feed sawing and zone adaptive damping steps: Control the feed unit to drive the operating arm to swing, so that the circular saw blade cuts into the bar stock; when the circular saw blade enters the radial cutting force change range of 1 / 3 to 2 / 3 of the bar stock diameter, the control system uses an independent drive device or passive viscous shear force to create a controllable differential speed between the left and right damping rings and the circular saw blade. This differential speed is one of the following two forms: same-direction accelerated rotation and opposite-direction rotation; at the same time, the control system monitors the vibration acceleration of the circular saw blade and the instantaneous gap between the circular saw blade and the left and right damping rings in real time. Dynamic air gap adjustment and collision avoidance steps: When a high-frequency impact component representing chip intrusion is detected in the vibration signal, the control system instantly pushes the damping ring axially open via a piezoelectric actuator, briefly increasing the air gap width from 0.05-0.2mm to 0.5mm, and maintaining a positive pressure air curtain to blow away chips, then returns to the normal air gap; when the air gap between the circular saw blade and the left and right damping rings is less than 0.03mm or the lateral amplitude of the circular saw blade exceeds 0.4mm, the control system immediately performs at least one of the following operations: emergency retraction, reduction of feed rate, or stopping spindle rotation; Post-wetting and finishing steps: After sawing is completed and the circular saw blade exits the kerf, control the damping ring to continue rotating at a speed of 5-20 rpm for 5-15 seconds to clean and protect the circular saw blade with oil. Then stop the rotation of the left and right damping rings and the circular saw blade, release the clamping unit, and complete one cutting cycle.

[0016] The beneficial effects of this invention are: 1. This invention symmetrically arranges non-contact left and right damping rings on both sides of the cutting area of ​​a circular saw blade. A small, uniform air gap is maintained between the rings and the side of the saw blade, and this air gap is filled with semi-solid damping grease. During sawing, the control system drives the damping rings to rotate at a controllable differential speed with the saw blade, generating a stable squeezing oil film effect and viscous shear damping force in the air gap. This damping mechanism directly acts on the lateral vibration mode of the saw blade, effectively absorbing and dissipating chatter energy.

[0017] 2. This invention eliminates this source of fatigue failure by continuously suppressing chatter. Simultaneously, the oil groove on the inner end face of the damping ring continuously coats the saw blade surface with semi-solid damping grease, forming a protective lubricating film and reducing friction and wear between the saw blade and the chips and workpiece.

[0018] 3. This invention eliminates the traditional lubrication method of spraying large amounts of cutting fluid. The damping medium is a semi-solid damping grease, which is confined within a tiny air gap between the damping ring and the saw blade, and is precisely applied to the saw blade surface through a spin coating method. Simultaneously, a positive pressure air curtain generator on the periphery forms an annular air curtain at the air gap inlet, effectively preventing damping grease leakage and chip intrusion. There is no cutting fluid splashing during the entire sawing process, keeping the workshop floor and equipment surfaces clean, meeting green manufacturing requirements, and reducing the cost of cutting fluid procurement and wastewater treatment.

[0019] 4. This invention integrates vibration sensors and gap monitoring sensors, and, in conjunction with multiple operating modes of the control system, possesses comprehensive intelligent safety protection capabilities. When chips are detected intruding into the air gap, the system can instantly push the damping ring axially and enhance the air curtain blowing to achieve dynamic self-cleaning. When the gap is detected to be too small or the amplitude exceeds the standard, the system immediately performs emergency blade retraction, deceleration, or shutdown, effectively preventing the saw blade from colliding with the damping ring. Furthermore, the adaptive differential speed algorithm can dynamically adjust the damping intensity according to the real-time vibration state, automatically switching to reverse rotation or increasing the differential speed when severe chatter occurs, quickly suppressing vibration. These functions ensure the safe operation of the equipment under complex working conditions.

[0020] 5. In this invention, the damping ring is mounted on the operating arm via a follower arm, and the swing axis of the follower arm is parallel to or coincides with the swing axis of the operating arm. This design ensures that the damping ring always follows the saw blade during the saw blade's swing feed process, maintaining the optimal damping area unchanged. Whether cutting large-diameter or small-diameter bars, the damping ring can effectively cover the contact area between the saw blade and the workpiece, requiring no manual adjustment, exhibiting strong adaptability, and facilitating mass production applications. Attached Figure Description

[0021] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0022] Figure 1 This is a schematic diagram of the installation position of the passive constraint damping vibration suppression system of the present invention in Example 1; Figure 2 This is a schematic diagram of the passive constraint damping vibration suppression system of the present invention in Example 1; Figure 3 This is a schematic diagram of the air gap structure of the present invention in Example 1; Figure 4 This is a schematic diagram of the structure of the left damping ring of the present invention in Example 1; Figure 5 This is a schematic diagram of the oil tank structure of the present invention in Example 1; Figure 6 This is a schematic diagram of the passive constraint damping vibration suppression system of the present invention in Example 2.

[0023] Figure 7 This is a schematic diagram of the workflow of the present invention.

[0024] Explanation of reference numerals in the attached drawings: 1-Bed, 2-Worktable, 3-Operating arm, 4-Circular saw blade, 5-Feed unit, 6-Bar stock, 7-Left damping ring, 8-Right damping ring, 9-Follower arm, 10-Air gap, 11-Oil groove, 12-Elastic self-lubricating coating, 13-Miniature nozzle, 14-Spiral chip conveyor, 15-Rolling bearing, 16-Servo motor, 18-Vibration sensor, 19-Gap monitoring sensor, 24-Clamping unit, 28-Positive pressure air curtain generator, 29-Independent drive device, 30-Reducer, 31-Transmission mechanism, 36-Horizontal guide rail, 37-Sliding block, 38-Linear drive mechanism. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the various embodiments of this invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this invention to facilitate a better understanding of this application. However, the technical solutions claimed in the claims of this application can be implemented even without these technical details and with various variations and modifications based on the following embodiments.

[0026] like Figure 1-7 As shown, this embodiment provides a high-speed circular saw for processing bearing forgings. The equipment mainly includes a bed 1, a worktable 2 fixed on the bed 1, an operating arm 3 mounted on the worktable 2, a circular saw blade 4 mounted on the output end of the operating arm 3, a feed unit 5 (usually a ball screw mechanism or hydraulic cylinder driven by a servo motor) for driving the operating arm 3 to swing around a fixed axis, a clamping unit 24 for clamping bar stock 6, an automatic feeding unit (not shown in the figure, a standard servo feeding mechanism can be used), and a central control system.

[0027] To address the problem of lateral chatter that easily occurs during high-speed sawing of bearing steel (such as GCr15), the core improvement of this invention lies in the addition of a passive constraint damping vibration suppression system, which specifically includes: The left damping ring 7 and the right damping ring 8 are both made of copper alloy (such as chromium zirconium copper) with a thermal conductivity of 120 W / (m·K) and are symmetrically arranged on both sides of the cutting area of ​​the circular saw blade 4. Here, the "cutting area" refers to the part where the circular saw blade 4 is in contact with the bar stock 6 and is cutting. During operation, the cutting section of the circular saw blade 4 (i.e. the saw blade part that participates in cutting) passes through the annular space between the left damping ring 7 and the right damping ring 8.

[0028] The left damping ring 7 and the right damping ring 8 are mounted on a swingable follower arm 9 via a high-rigidity bearing seat. The rear end of the follower arm 9 is mounted on the frame of the operating arm 3 via a rotating shaft, and the axis of the rotating shaft is completely coincident with the swing axis of the operating arm 3. This "coaxial follower" design ensures that no matter what angle the operating arm 3 swings to, the damping ring can always be directly behind the cutting area of ​​the saw blade, providing continuous and optimal damping effect.

[0029] The left damping ring 7 and the right damping ring 8 maintain a uniform annular gap, i.e., an air gap 10, between their inner end faces facing the circular saw blade 4 and the corresponding side faces of the circular saw blade 4. In this embodiment, under normal sawing conditions, the width of the air gap 10 is precisely controlled to be 0.1 mm. This air gap is the core space for forming the extrusion oil film damping.

[0030] Please combine Figure 3 The inner end faces of the left and right damping rings are provided with spiral oil grooves 11. The oil grooves 11 are 0.5 mm deep, 1.0 mm wide, and have a helix angle of 30°. The oil grooves 11 are filled with semi-solid damping grease. The damping grease has a cone penetration of 280° at 25°C (belonging to NLGI 2# grade) and a dropping point as high as 200°C, exhibiting good high-temperature stability and shear stability. The outer side of the oil grooves 11 (near the outer circumference of the damping rings) is also provided with a spiral chip removal groove 14, which is 0.4 mm deep, has a helix angle of 70°, and is designed to be right-handed.

[0031] A 0.2 mm thick polyimide-based composite coating is applied to the inner end face of the damping ring (including the oil groove surface) using a spraying process. This coating contains 10% by mass of molybdenum disulfide solid lubricant. This coating ensures that the saw blade surface will not be scratched in the rare case of accidental contact, while also providing basic dry lubrication.

[0032] The positive pressure air curtain generator 28 is annular and surrounds the left damping ring 7 and the right damping ring 8. It has 12 evenly distributed micro-nozzles 13 with a diameter of 0.8 mm, oriented towards the inlet of the air gap 10. During operation, the device introduces clean compressed air at 0.4-0.6 MPa, forming a high-speed annular air curtain around the air gap 10, effectively preventing external chips and coolant from entering the damping gap.

[0033] In this embodiment, the left damping ring 7 and the right damping ring 8 are mounted on the follower arm 9 by a pair of P4-grade precision angular contact ball bearings 15. The bearings are subjected to a light preload to improve rigidity. The damping rings do not have independent motors, and their rotational motion is passively driven by the viscous shear force generated by the damping grease in the air gap 10 when the circular saw blade 4 rotates.

[0034] The control system (including a PLC or industrial computer) is configured to operate according to the following logic: Pre-wetting mode: Before sawing begins, the spindle motor has already driven the circular saw blade 4 to rotate to its operating speed (e.g., 80 m / s linear velocity). At this time, the control system does not actively drive the damping ring, but waits for 2 seconds, allowing the saw blade to slowly rotate the damping ring (approximately 5-10 rpm) through viscous shear force, evenly coating the damping grease in the oil groove onto both sides of the saw blade surface, forming a damping grease film approximately 0.1 mm thick. This process lasts for 3 seconds. Feed sawing and zone adaptive damping: The feed unit 5 drives the manipulator arm 3 to swing, causing the circular saw blade 4 to cut into the bar stock 6. When the saw blade cuts to a depth of 1 / 3 to 2 / 3 of the bar stock diameter, the radial cutting force is at its maximum, and the risk of chatter is highest. At this time, because the speed difference between the saw blade and the damping ring is stabilized at about 3%-5% of the saw blade speed (for example, saw blade speed 2000 rpm, damping ring speed 60-100 rpm), the viscous shear damping reaches its peak, effectively suppressing chatter.

[0035] Post-immersion mode: After sawing is completed and the circular saw blade 4 exits the kerf, the control system continues to keep the spindle rotating for 5 seconds, allowing the damping ring to continue rotating, cleaning the fine iron filings adhering to the surface of the saw blade, and leaving a protective damping grease film to prevent the saw blade from rusting, and then stops the spindle rotation.

[0036] like Figure 6 As shown, the main difference between Example 2 and Example 1 is that the damping ring is driven in a more proactive and intelligent manner.

[0037] Please see Figure 6 In this embodiment, an independent drive unit 29 is used. This unit includes a small servo motor 16, a planetary reducer 30 (reduction ratio 10:1), and a synchronous belt drive mechanism 31. The servo motor 16 is fixed to the follower arm 9 via a motor mount, and its output shaft is connected to the rotating shaft of the left damping ring 7 (or the right damping ring 8) via the reducer 30 and the synchronous belt. Each of the left and right damping rings is controlled by an independent servo drive system.

[0038] Furthermore, in order to achieve dynamic adjustment of the air gap, this embodiment introduces the following... Figure 2 The axial adjustment mechanism is shown. An air gap adjustment structure is provided between the left damping ring 7 (and the right damping ring 8) and the corresponding follower arm 9: a linear guide rail 36 is fixed on the follower arm 9, a sliding block 37 slides on the guide rail, and the bearing seat of the damping ring is fixed on the sliding block 37. The sliding block 37 is driven by a high-response piezo actuator 20, with a minimum displacement resolution of 0.1 μm. Simultaneously, a Keyence capacitive displacement sensor 19 is installed on the follower arm 9 as a gap monitoring sensor to measure the instantaneous distance between the saw blade and the end face of the damping ring in real time, with a measurement accuracy of ±0.5 μm. Furthermore, a piezoelectric accelerometer 18 is also installed on the follower arm 9 as a vibration sensor.

[0039] The controller within the control system (using a DSP+FPGA architecture) executes the following enhanced operating modes: Dynamic air gap adjustment mode: During normal sawing, the controller uses a PID algorithm to control the piezoelectric actuator 20, stabilizing the air gap 10 at 0.08 mm. When the vibration sensor 18 detects a high-frequency impact component with a frequency higher than 2 kHz and a sudden increase in amplitude (typically characterized by chips embedding in the gap), the controller immediately sends a step signal to the piezoelectric actuator 20, pushing the damping ring axially open within 0.01 seconds, briefly increasing the air gap 10 to 0.5 mm. Simultaneously, the air supply pressure of the positive pressure air curtain generator 28 instantly increases from 0.4 MPa to 0.8 MPa, lasting for 0.2 seconds, forcefully blowing away the intruding chips. Subsequently, the controller restores the air gap to 0.08 mm. The entire process is completed within 0.5 seconds, with no significant impact on the sawing process.

[0040] Enhanced damping mode in the cutting area: The swing angle of the operating arm 3 is monitored in real time by an angle encoder (not shown) to calculate the real-time cutting depth of the saw blade. When the controller determines that the saw blade has cut into the bar stock between 1 / 3 and 2 / 3 of its diameter, it actively controls the left and right damping rings to rotate in the opposite direction to the circular saw blade 4 via an independent drive device 29. For example, the saw blade rotates clockwise at 2000 rpm, while the damping rings rotate counterclockwise at 50 rpm. Compared to passive co-rotation, this reverse differential speed mode can increase the viscous shear force by 3-5 times, greatly increasing the damping effect and effectively suppressing severe chatter during deep cutting.

[0041] Vibration Adaptive Differential Control: The controller acquires the acceleration signal from the vibration sensor 18 in real time (FFT analysis). When the effective value of the vibration acceleration exceeds 0.3g (gravitational acceleration), the adaptive algorithm (such as fuzzy PID) begins to dynamically adjust the output speed of the independent drive device 29, increasing the differential speed. When the vibration acceleration exceeds 0.5g, the controller determines it to be severe flutter and immediately performs two operations: first, it reverses the rotation direction of the damping ring; second, it increases the differential speed to 90% of the preset maximum value (in this embodiment, the preset maximum differential speed is 150 rpm). Actual testing shows that this operation can reduce the vibration acceleration to below 0.1g within 0.1 seconds.

[0042] Collision avoidance safety protection: The gap monitoring sensor 19 provides real-time feedback on the gap between the saw blade and the damping ring. When the controller measures a distance less than 0.03mm (i.e., contact is imminent), or the vibration sensor 18 measures a saw blade lateral amplitude (obtained through integral acceleration signal) exceeding 0.4mm, the controller immediately triggers a high-priority interrupt and performs the following operations: 1) issues an emergency retraction command (rapid reverse movement) to the feed unit 5; 2) reduces the spindle speed to below 500rpm within 0.2 seconds; 3) simultaneously retracts the damping ring axially to a safe position (air gap 1.0mm). This safety mechanism effectively prevents the saw blade from breaking or the equipment from being damaged.

[0043] Example 3: This example discloses the complete working method of the above-described circular saw machine, and is particularly applicable to the equipment described in Example 2. The method includes the following steps: Equipment startup and pre-wetting steps: The control system starts the spindle motor, accelerating the circular saw blade 4 to its operating speed (e.g., 3000 rpm). Simultaneously, the positive pressure air curtain generator 28 is activated to establish an annular air curtain. The controller, through the independent drive device 29, drives the left and right damping rings to rotate in the same direction as the saw blade at a speed of 15 rpm. Relying on the pumping action of the oil tank 11, semi-solid damping grease is continuously coated on both sides of the circular saw blade 4, forming a continuous damping grease film with a thickness of approximately 0.12 mm. This process lasts for 4 seconds.

[0044] Feed sawing and zone adaptive damping steps: After pre-impregnation, the controller controls the feed unit 5 to drive the manipulator arm 3 to swing, and the circular saw blade 4 begins to cut into the bar stock 6 at a preset feed speed (e.g., 30 mm / s). During the cutting process, the controller calculates the cutting depth in real time through the manipulator arm angle encoder. When the cutting depth reaches 1 / 3 of the bar stock diameter, the controller automatically switches to the "cutting zone enhanced damping mode" and instructs the independent drive device 29 to rotate the left and right damping rings in opposite directions to the circular saw blade 4, with the rotation speed set to 80 rpm. At the same time, the controller begins to monitor the data from the vibration sensor 18 and the gap monitoring sensor 19 in real time at a sampling rate of 2 kHz.

[0045] Dynamic air gap adjustment and collision avoidance procedures: During sawing, if the vibration sensor 18 detects a characteristic high-frequency impact signal (indicating that chips are being drawn into the air gap), the controller immediately initiates the dynamic air gap adjustment program: the piezoelectric actuator 20 instantaneously pushes the damping ring axially by 0.42mm, increasing the total air gap width from 0.08mm to 0.5mm. Simultaneously, the positive pressure air curtain pressure jumps from 0.4MPa to 0.7MPa, lasting for 0.3 seconds. Subsequently, the piezoelectric actuator 20 resets, and the air gap returns to 0.08mm.

[0046] During this process, if the distance value fed back by the gap monitoring sensor 19 is less than 0.03 mm or the calculated lateral amplitude of the saw blade exceeds 0.4 mm, the controller will immediately execute the highest priority safety operation: sending an "emergency retraction" command to the feed unit 5 (retraction speed 100 mm / s), sending a "rapid stop" command to the spindle driver (braking time 0.3 seconds), and sending a "full stroke retraction" command to the piezoelectric actuator 20. The entire safety response process takes less than 0.05 seconds.

[0047] Post-wetting and finishing steps: After sawing is complete and the circular saw blade 4 is fully withdrawn from the kerf under the drive of the feed unit 5, the controller continues to maintain the spindle rotation and damping ring drive. Specifically, the damping ring is instructed to continue rotating at 10 rpm (in the same direction as the saw blade) for 10 seconds. During this process, the damping ring throws out the iron filings remaining on the saw blade surface through the spiral chip removal groove 14 and recoats a uniform layer of damping grease film for rust prevention and protection. Subsequently, the controller issues commands to stop the damping ring rotation, stop the spindle rotation, close the positive pressure air curtain, and release the clamping unit 24 in sequence. Finally, the next section of bar stock is pushed through the automatic feeding unit, completing one complete cutting cycle.

[0048] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A high-speed circular saw for processing bearing forgings, comprising a bed (1), a worktable (2) disposed on the bed (1), an operating arm (3) mounted above the worktable (2), a circular saw blade (4) mounted on the operating arm (3), a feed unit (5) for driving the operating arm (3) to swing, a clamping unit (24) for clamping bar stock (6), an automatic feeding unit, and a control system; characterized in that, It also includes a passively constrained damping vibration suppression system, which comprises: The left damping ring (7) and the right damping ring (8) are symmetrically arranged on both sides of the cutting area of ​​the circular saw blade (4). The cutting area refers to the part where the circular saw blade (4) contacts the bar stock (6) and cuts it. The cutting section of the circular saw blade (4) passes between the left damping ring (7) and the right damping ring (8). The left damping ring (7) and the right damping ring (8) are mounted on the frame of the operating arm (3) via a swingable follower arm (9). The swing axis of the follower arm (9) is parallel or coincident with the swing axis of the operating arm (3). The left damping ring (7) and the right damping ring (8) maintain a uniform annular air gap (10) of 0.05-0.5mm between the inner end face of the left damping ring (7) and the corresponding side face of the circular saw blade (4). Multiple oil grooves (11) are provided on the inner end face of the left damping ring (7) and the right damping ring (8), and the oil grooves (11) are filled with damping medium. The inner end face of the left damping ring (7) and the right damping ring (8) is coated with an elastic self-lubricating coating (12) with a thickness of 0.1-0.3mm. It also includes a positive pressure air curtain generator (28) set around the left damping ring (7) and the right damping ring (8). The positive pressure air curtain generator (28) is equipped with multiple micro nozzles (13) that spray compressed air into the air gap (10) inlet to form an annular air curtain around the air gap (10). The control system is configured to: during the sawing process, cause the left damping ring (7) and the right damping ring (8) to rotate relative to the circular saw blade (4), thereby creating a differential speed between the left damping ring (7) and the right damping ring (8) and the circular saw blade (4), and continuously apply the damping medium to the surface of the circular saw blade (4).

2. The high-speed circular saw for processing bearing forgings according to claim 1, characterized in that: The damping medium is a semi-solid damping grease, with a cone penetration of 250-300 at 25℃ and a dropping point ≥180℃; the oil groove (11) is one of a spiral groove, a radial straight groove, and a mesh groove, with a groove depth of 0.1-1.0mm and a groove width of 0.5-2.0mm; a spiral chip removal groove (14) is also provided on the outer side of the inner end face of the damping ring, with a depth of 0.3-0.5mm, a spiral angle greater than 60°, and a spiral direction set to throw the chips that enter the air gap (10) away from the circular saw blade (4) when the damping ring rotates.

3. A high-speed circular saw for processing bearing forgings according to claim 2, characterized in that: The left damping ring (7) and the right damping ring (8) are mounted on the follower arm (9) via rolling bearings (15). The rotational motion is passively driven by the viscous shear force generated by the damping grease in the air gap (10) when the circular saw blade (4) rotates, so that the rotational speed of the left damping ring (7) and the right damping ring (8) is 1%-10% of the rotational speed of the circular saw blade (4) and the rotational direction is the same. The rolling bearing (15) is an angular contact ball bearing with a precision of P4 or above and is subjected to a light preload. The outer diameter of the damping ring is 0.4-0.7 times the diameter of the circular saw blade (4), and the axial width of the damping ring is 5-20 mm.

4. A high-speed circular saw for processing bearing forgings according to claim 1, characterized in that: It also includes an independent drive unit (29), which includes a servo motor (16), a reducer (30) and a transmission mechanism (31). The servo motor (16) is fixed to the follower arm (9) by a motor mount. The transmission mechanism (31) is at least one of the following mechanisms: a gear transmission mechanism, a synchronous belt transmission mechanism, and a friction wheel transmission mechanism. The independent drive unit (29) is used to independently control the speed and direction of rotation of the left damping ring (7) and the right damping ring (8).

5. A high-speed circular saw for processing bearing forgings according to claim 1, characterized in that: The axial positions of the left damping ring (7) and the right damping ring (8) can be adjusted independently; each left damping ring (7) and the right damping ring (8) is provided with an air gap adjustment structure between itself and the corresponding follower arm (9). The adjustment structure includes a horizontal guide rail (36) set on the operating arm (9), a sliding block (37) that moves along the horizontal guide rail (36) is provided on the horizontal guide rail (36), and the sliding block (37) is fixed to the follower arm (9). The horizontal guide rail (36) is provided with a linear drive mechanism (38) that drives the sliding block (37) to make precise movements.

6. A high-speed circular saw for processing bearing forgings according to claim 5, characterized in that: The control system is also configured to perform the following multiple operating modes: Pre-wetting mode: Before sawing begins and after the circular saw blade (4) has rotated, drive the left damping ring (7) and the right damping ring (8) to rotate unidirectionally or swing back and forth at a speed of 5-30 rpm for 1-5 seconds. Enhanced damping mode in the cutting area: When the circular saw blade (4) cuts into the bar stock (6) in the range of 1 / 3 to 2 / 3 of the diameter, drive the left damping ring (7) and the right damping ring (8) to rotate in the opposite direction to the circular saw blade (4) at a speed of 20-100 rpm. Dynamic air gap adjustment mode: During normal sawing, the air gap (10) is maintained at 0.05-0.2mm. When the vibration sensor (18) detects a high-frequency impact signal, the control system (26) pushes the left damping ring (7) and the right damping ring (8) axially open instantly through the linear drive mechanism, so that the air gap (10) is briefly increased to 0.5mm and the positive pressure air curtain is activated to blow away the chips, and then returns to the normal air gap (10). Post-immersion mode: After sawing is completed and before the circular saw blade (4) stops swinging, drive the left damping ring (7) and right damping ring (8) to continue rotating at a speed of 5-20 rpm for 5-15 seconds.

7. A high-speed circular saw for processing bearing forgings according to claim 6, characterized in that: It also includes a vibration sensing and collision warning component, which includes: At least one vibration sensor (18) is mounted on the follower arm (9) or the operating arm to detect the lateral vibration amplitude, frequency and acceleration of the circular saw blade (4) in real time. The gap monitoring sensor (19) is one of the following two types of sensors: capacitive displacement sensor or laser displacement sensor. It is installed on the follower arm (9) and used to measure the instantaneous distance between the circular saw blade (4) and the inner end faces of the left damping ring (7) and the right damping ring (8) in real time. The control system includes a controller that immediately performs at least one of the following operations when the gap monitoring sensor (19) detects a distance less than 0.03 mm or the vibration sensor (18) detects an amplitude exceeding 0.4 mm: emergency tool retraction, reducing feed rate, or stopping spindle rotation. The controller also uses an adaptive algorithm to dynamically adjust the output speed of the independent drive device (29) based on the feedback signal of the vibration sensor (18), so that the differential speed between the left damping ring (7) and the right damping ring (8) and the circular saw blade (4) matches the current flutter state in real time; when the detected vibration acceleration exceeds 0.5g, the controller immediately performs at least one of the following two operations: switching the rotation direction of the left damping ring (7) and the right damping ring (8) to the opposite direction, and increasing the differential speed to 80%-100% of the preset maximum value.

8. A high-speed circular saw for processing bearing forgings according to claim 1, characterized in that: The left damping ring (7) and the right damping ring (8) are made of copper alloy with a thermal conductivity ≥100 W / (m·K); the elastic self-lubricating coating (12) is a polyimide-based composite coating, in which 5%-15% by mass of solid lubricant is added, and the solid lubricant is at least one of the following two substances: molybdenum disulfide and graphite.

9. A high-speed circular saw for processing bearing forgings according to any one of claims 1 to 8, characterized in that; The method of using the circular saw includes the following steps: Equipment start-up and pre-wetting steps: Start the spindle motor to rotate the circular saw blade (4), and at the same time start the positive pressure air curtain generator (28) to drive the left damping ring (7) and the right damping ring (8) to rotate relative to the circular saw blade (4). The semi-solid damping grease is applied to both sides of the circular saw blade (4) through the oil groove (11) on the inner end face of the damping ring to form a damping grease film with a thickness of 0.05-0.5mm. This pre-wetting process lasts for 1-5 seconds. Feed sawing and zone adaptive damping steps: The control feed unit (5) drives the operating arm (3) to swing, so that the circular saw blade (4) cuts into the bar stock (6); when the circular saw blade (4) enters the radial cutting force change range of 1 / 3 to 2 / 3 of the diameter of the bar stock (6), the control system (26) uses an independent drive device (29) or passive viscous shear force to form a controllable differential speed between the left damping ring (7) and the right damping ring (8) and the circular saw blade (4). The differential speed is one of the following two forms: same-direction accelerated rotation and opposite-direction rotation; at the same time, the control system (26) monitors the vibration acceleration of the circular saw blade (4) and the air gap (10) between the circular saw blade (4) and the left damping ring (7) and the right damping ring (8) in real time. Dynamic air gap adjustment and collision avoidance steps: When a high-frequency impact component representing chip intrusion is detected in the vibration signal, the control system instantly pushes the damping ring along the axial direction through the piezoelectric actuator (20), so that the width of the air gap (10) briefly increases from 0.05-0.2mm to 0.5mm, and maintains a positive pressure air curtain to blow away the chips, and then returns to the normal air gap (10); When the instantaneous gap (10) between the circular saw blade (4) and the left damping ring (7) and the right damping ring (8) is less than 0.03mm or the transverse amplitude of the circular saw blade (4) exceeds 0.4mm, the control system immediately performs at least one of the following operations: emergency retraction, reducing the feed rate, and stopping the spindle rotation; Post-wetting and finishing steps: After sawing is completed and the circular saw blade (4) exits the kerf, control the damping ring to continue rotating at a speed of 5-20 rpm for 5-15 seconds to clean and protect the circular saw blade (4). Then stop the rotation of the left damping ring (7) and the right damping ring (8) with the circular saw blade (4), release the clamping unit (24), and complete one cutting cycle.

Images