Magneto-rheological self-adaptive locking clamp for turning and machining method of magneto-rheological self-adaptive locking clamp

Abstract

The invention discloses a magneto-rheological self-adaptive locking clamp for turning and a machining method of the magneto-rheological self-adaptive locking clamp, and belongs to the technical field of precision workpiece machining equipment. Comprising a flexible contact shell making contact with a workpiece, a locking unit arranged at the outer end of the flexible contact shell and an outer shell arranged outside the locking unit. The locking unit comprises an axial locking assembly and a radial pushing assembly, and the axial locking assembly is a self-adaptive locking assembly with an integrated magnetic circuit; the radial pushing assembly is a rigid pushing assembly. By means of the clamp, high-precision, lossless and self-adaptive locking of workpieces is achieved, and clamping deformation of thin-wall and special-shaped workpieces is effectively restrained. Through a composite mechanism of magneto-rheological locking and mechanical rigid pushing, the dynamic stability of the machining process is remarkably enhanced, meanwhile, it is ensured that the locking force is quick in response, low in energy consumption and stable in long-term work, and the machining quality and efficiency and the reliability of the clamp are improved.

Description

Technical Field

[0001] This invention relates to the field of precision workpiece machining equipment, and in particular to a magnetorheological adaptive locking fixture for turning and its machining method. Background Technology

[0002] In high-precision mechanical manufacturing, especially in high-end industries such as aerospace and precision optics, the structure of core components is developing towards lightweight, thin-walled, and complex designs. However, these components suffer from problems such as weak rigidity, poor stability, and high value. Workpiece clamping technology during turning has become a bottleneck restricting machining accuracy, surface quality, and production efficiency. Existing mainstream fixture technologies have many shortcomings.

[0003] Traditional mechanical fixtures use "rigid contact." Taking three-jaw chucks and spring collets as examples, concentrated point or line contact forces are applied through discrete jaws, which can easily cause indentations and microcracks on the surface of thin-walled parts, impairing fatigue strength. They can also introduce uneven assembly stress, leading to elastic deformation. During processing, stress rebalancing can cause surface distortion and loss of form and position tolerances. The cost of mitigation is the sacrifice of flexibility and efficiency.

[0004] Hydraulic and pneumatic clamps face bottlenecks in terms of "uniform pressure distribution" and "intelligent control." While hydraulic expansion mandrels can provide more uniform surface pressure, they rely on the manufacturing precision of the rubber bladder, depend on external equipment for power, and have complex and large systems. They also suffer from problems such as pressure fluctuations, leakage and contamination, and seal aging. Furthermore, they have slow response speeds and difficulty in adjusting clamping force accurately in real time, thus failing to meet the demands of modern intelligent machining.

[0005] In summary, there is an urgent need for a high-precision fixture for turning to meet the requirements of various machining processes for workpieces. Summary of the Invention

[0006] The purpose of this invention is to provide a magnetorheological adaptive locking fixture for turning and its machining method, achieving high-precision, non-destructive adaptive locking of the workpiece and effectively suppressing clamping deformation of thin-walled and irregularly shaped parts. Through a combined mechanism of magnetorheological locking and mechanical rigid pushing, the dynamic stability of the machining process is significantly enhanced, while ensuring agile locking force response, low energy consumption, and long-term stable operation, thereby improving machining quality, efficiency, and fixture reliability.

[0007] To achieve the above objectives, the present invention provides a magnetorheological adaptive locking fixture for turning, which is disposed directly below the milling cutter and above the worktable, including a flexible contact shell that contacts the workpiece, a locking unit disposed at the outer end of the flexible contact shell, and an outer shell disposed outside the locking unit; the outer shell is made of insulating material.

[0008] The locking unit includes an axial locking assembly and a radial pushing assembly. The axial locking assembly is an adaptive locking assembly with an integrated magnetic circuit; the radial pushing assembly is a rigid pushing assembly.

[0009] Preferably, the axial locking assembly includes a pole shoe, an excitation coil, a magnetorheological fluid layer, and an upper magnetic cover plate and a lower magnetic cover plate for forming a closed loop; The excitation coil is wound around the pole shoe, and the magnetorheological fluid layer is disposed in the gap formed by the excitation coil, the pole shoe, the upper magnetic cover plate, and the lower magnetic cover plate.

[0010] Preferably, the pole shoe is a type I pole shoe, comprising a front pole tip, a pole body, and a rear pole tip arranged sequentially. Several pole shoes are provided, arranged in a ring symmetrically on the outside of the flexible contact shell. The front pole tip and the rear pole tip are arc-shaped plates with the same axis. The outer arc length of the front pole tip is smaller than the inner arc length of the rear pole tip. The front pole tip is located on the side closer to the flexible contact shell, and the rear pole tip is located on the side closer to the outer shell. The rear pole tip and the outer shell are connected by a connecting protrusion.

[0011] Preferably, the upper magnetic cover plate and the lower magnetic cover plate are any one of soft magnetic stainless steel, electrical pure iron or silicon steel sheet. The upper magnetic cover plate is connected to the outer shell by a bolt group. An insulating boss is provided inside the outer shell. The lower magnetic cover plate is placed on the insulating boss. The upper magnetic cover plate, the lower magnetic cover plate and the insulating boss are all provided with holes for the flexible contact shell to pass through.

[0012] Preferably, the magnetorheological fluid layer is a flexible sealed bag containing magnetorheological fluid. The magnetorheological fluid layer undergoes a solid-phase transformation under the action of a magnetic field and transmits radial pressure to the flexible contact shell.

[0013] Preferably, the radial actuation assembly includes a telescopic mechanism and a rigid rotation mechanism actuated by the telescopic mechanism.

[0014] Preferably, the telescopic structure includes a telescopic rod disposed at the bottom of the outer shell, and a push plate disposed at the other end of the telescopic rod. The rigid rotation mechanism includes a plurality of rotating rods and a push ball corresponding to the number of rotating rods. The rotating rods are connected to the inner wall of the outer shell by a hinge consisting of an ear plate and a pin. The push ball is disposed at the tail end of the rotating rod and placed on the push plate. The upper edge of the push ball contacts the bottom edge of the flexible contact shell.

[0015] Preferably, the outer casing has a wire outlet hole for powering on and off the locking unit, and a heat sink is also provided inside the outer casing.

[0016] This invention also discloses a machining method for a magnetorheological adaptive locking fixture for turning, comprising the following steps: S1. Workpiece clamping and initial positioning: The workpiece to be processed is placed in the inner cavity of the flexible contact shell. At this time, the magnetorheological liquid layer is in a liquid flow state without electricity, the radial pushing component is in a retracted state, and the flexible contact shell has no locking force on the workpiece. The operator can slightly adjust the workpiece to achieve accurate initial positioning. S2, Composite Locking Sequence Activation: An initial current is passed through the excitation coil of the axial locking assembly to generate a magnetic field, causing the magnetorheological liquid layer surrounding the workpiece to undergo a solid-phase transformation from a liquid state to a near-solid state. This results in a uniform and adaptive main locking force being applied to the workpiece through the flexible contact shell. This main locking force can automatically adapt to the minute irregularities on the workpiece surface, achieving an enveloping flexible locking of the upper part of the workpiece. The telescopic mechanism of the radial pushing assembly is activated, driving the push plate to move upward. By pushing the ball, multiple circumferentially distributed rotating rods are lifted, causing the rotating rods to rotate inward and upward around their hinge points, applying a concentrated, rigid auxiliary clamping force from the bottom of the workpiece. S3. Adaptive dynamic locking and turning: During the turning process, the cutting force, vibration signal or preset machining condition parameters are monitored in real time; the current value input to the excitation coil is dynamically adjusted, thereby steplessly and in real time adjusting the shear yield stress of the magnetorheological fluid layer, that is, adjusting the magnitude of the main locking force applied to the workpiece; S4. Machining Completion and Locking Release: After the turning process is completed, the telescopic mechanism of the radial push component is retracted, which drives the push plate to move down. The rotating rod opens outward under the action of gravity or the reset mechanism, releasing the auxiliary clamping force on the bottom of the workpiece. Subsequently, the current of the excitation coil is cut off, the magnetic field disappears, the magnetorheological liquid layer quickly recovers from a near-solid state to a liquid state, and the main locking force is completely released. The machined workpiece is then removed.

[0017] Preferably, in step S2, after the excitation coil is energized, a closed magnetic circuit is formed. The path of the closed magnetic circuit is: rear pole tip - pole body - magnetorheological liquid layer - upper magnetic cover plate or lower magnetic cover plate - rear pole tip.

[0018] Therefore, the present invention employs the above-described magnetorheological adaptive locking fixture for turning and its machining method, which has the following beneficial effects: 1. This invention uses an excitation coil to excite a magnetorheological fluid, causing it to solidify and apply uniform, enveloping radial pressure to a flexible contact shell. This automatically adapts to the microscopic irregularities on the workpiece surface, distributing contact stress evenly. Simultaneously, the magnetorheological locking force can be precisely controlled by current, releasing internal stress in the workpiece. This provides crucial process assurance for high-precision turning, especially for easily deformable parts.

[0019] 2. This invention sets up a composite locking mechanism with magnetorheological adaptive locking as the main component and mechanical rigid pushing as the auxiliary component. This mechanism effectively resists workpiece vibration and displacement caused by cutting force, enabling the fixture to actively suppress chatter and allowing for higher cutting parameters. This improves machining efficiency while ensuring quality, and is suitable for both roughing and finishing of workpieces.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the placement of a magnetorheological adaptive locking fixture for turning according to the present invention; Figure 2 This is a schematic diagram of the structure of a magnetorheological adaptive locking fixture for turning according to the present invention; Figure 3 This is a schematic diagram of the pole shoe of a magnetorheological adaptive locking fixture for turning according to the present invention; Figure 4 This is a schematic diagram of magnetorheological liquid diffusion in a magnetorheological adaptive locking fixture for turning according to the present invention. Figure label: a. Milling cutter; b. Workpiece to be processed; c. Worktable; 1. Magnetorheological adaptive locking clamp; 11. Outer shell; 12. Flexible contact shell; 13. Insulating boss; 14. Magnetorheological liquid layer; 15. Connecting protrusion; 16. Excitation coil; 17. Upper magnetic guide cover plate; 18. Bolt group; 19. Type I pole shoe; 191. Rear pole tip; 192. Pole body; 193. Front pole tip; 110. Lower magnetic guide cover plate; 111. Ear plate; 112. Rotating rod; 113. Push ball; 114. Push plate; 115. Telescopic rod. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following description will be provided in conjunction with the accompanying drawings of the embodiments of the present invention. Figures 1 to 4 The technical solutions of the present invention have been clearly and completely described. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be understood that the terms "center", "around", "lateral", "longitudinal", "length", "thickness", "angle", "up", "down", "left", "right", etc., which indicate the orientation or location, are limited to simplifying the description of this invention and are not specific locations or orientations. The above terms are not intended to limit this invention.

[0026] The specific connection methods of each part in this invention all adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment all adopt conventional models in the prior art. In addition, the circuit connection adopts conventional connection methods in the prior art, which will not be described in detail here.

[0027] Example like Figures 1-4 As shown, the present invention provides a magnetorheological adaptive locking fixture 1 for turning, which is disposed directly below the milling cutter a and above the worktable c. It includes a flexible contact shell 12 that contacts the workpiece, a locking unit disposed at the outer end of the flexible contact shell 12, and an outer shell 11 disposed outside the locking unit; the outer shell 11 is made of insulating material. The locking unit includes an axial locking assembly and a radial pushing assembly. The axial locking assembly is an adaptive locking assembly with an integrated magnetic circuit; the radial pushing assembly is a rigid pushing assembly.

[0028] The flexible contact shell 12 is in direct contact with the workpiece surface and can be made of silicone, polyurethane or other materials with certain elasticity and wear resistance. The flexible material design disperses the contact stress and conforms to the shape of the workpiece surface.

[0029] The locking unit, as the core component, includes an axial locking assembly and a radial pushing assembly. Together, they complete the composite locking function. Through the combined force from above and below, they ensure both clamping rigidity and meet dynamic machining requirements.

[0030] The axial locking assembly includes pole shoes, an excitation coil 16, a magnetorheological fluid layer 14, and an upper magnetically conductive cover plate 17 and a lower magnetically conductive cover plate 110 for forming a closed loop. The excitation coil 16 is wound around the pole shoes, and the magnetorheological fluid layer 14 is disposed in the gap formed by the excitation coil 16, the pole shoes, and the upper and lower magnetically conductive cover plates 17 and 110. The magnetorheological fluid layer 14 is a functional liquid that can undergo a solid-phase transformation under the action of an external magnetic field, and is a suspension containing magnetic particles. Its mechanical properties are controlled by the magnetic field to achieve dynamic adjustment of the locking force.

[0031] The pole shoe is a core component of a magnetic circuit with a low magnetic resistance path. In this embodiment, a type I pole shoe 19 is used, which includes a front pole tip 193, a pole body 192, and a rear pole tip 191 arranged sequentially. The front pole tip 193 can focus the magnetic field; the pole body 192 is the main conduction path of the magnetic field; and the rear pole tip 191 is used to form a closed magnetic circuit. Its arc-shaped design can reduce magnetic resistance and improve the efficiency of the magnetic circuit.

[0032] Several pole shoes are arranged in a ring-shaped configuration on the outer side of the flexible contact shell 12, ensuring uniform coverage of the magnetic field in the circumferential direction and avoiding the appearance of local weak field regions. The outer arc length of the front pole tip 193 is shorter than the inner arc length of the rear pole tip 191. Based on the principle of magnetic field convergence, a focusing effect is formed in the area of ​​the front pole tip 193 near the workpiece, strengthening the magnetic field strength of the key contact surface. In addition, the rear pole tip 191 is bonded to the outer shell 11 through connecting protrusions 15, ensuring mechanical stability, improving the continuity of the magnetic circuit and energy transfer efficiency, and solving the core problem of inconsistent locking force. This is especially suitable for high-precision machining requirements when turning thin-walled workpieces.

[0033] The upper magnetic guide plate 17 and the lower magnetic guide plate 110 are made of materials with high magnetic permeability and low coercivity, such as soft magnetic stainless steel, electrical pure iron, or silicon steel sheets. These materials are used to generate efficient magnetic flux conduction paths, preventing magnetic field dispersion due to increased magnetic reluctance, thereby improving the excitation efficiency of the magnetic field on the magnetorheological liquid layer 14. The upper magnetic guide plate 17 is mechanically connected to the outer shell 11 via bolts 18. The outer shell 11 contains an insulating boss 13 for supporting the lower magnetic guide plate 110, which can be made of an insulating material with electrical isolation properties. The upper magnetic guide plate 17, the lower magnetic guide plate 110, and the insulating boss 13 all have channel structures, allowing the flexible contact shell 12 to expand and contract to adapt to changes in workpiece shape.

[0034] The magnetorheological fluid layer 14 is a flexible, sealed bag containing the magnetorheological fluid, made of polymeric elastic materials, composite membrane materials, or rubber-like materials. Its purpose is to prevent the magnetorheological fluid from being directly exposed to the external environment, avoiding the risk of leakage due to mechanical vibration or pressure changes. Simultaneously, it conforms to the shape of the gap formed by the pole shoe and the magnetically conductive cover plate, allowing the liquid layer to uniformly fill the gap under the influence of a magnetic field, thereby improving the continuity of pressure transmission. The magnetorheological fluid layer 14 undergoes a solid-phase transformation under the influence of a magnetic field. By altering the rheological properties of the magnetorheological fluid through an applied magnetic field, it achieves a rapid transition from a liquid to a near-solid state. This is to ensure that the locking force can be efficiently transmitted to the flexible contact shell 12.

[0035] When the excitation coil 16 is energized, it forms a closed magnetic circuit. The path of the closed magnetic circuit is: rear pole tip 191 - pole body 192 - magnetorheological liquid layer 14 - upper magnetic cover plate 17 or lower magnetic cover plate 110 - rear pole tip 191.

[0036] During the locking and starting phase, when the excitation coil 16 is energized, the magnetic field originates from the rear pole tip 191, is stably conducted along the pole body 192 to the magnetorheological fluid layer 14, and then returns to the rear pole tip 191 via the upper magnetic guide plate 17 or the lower magnetic guide plate 110, forming a complete closed loop. Utilizing the structural characteristics of the type I pole shoe 19, the magnetic field energy is concentrated in the magnetorheological fluid layer 14 region, effectively preventing the magnetic field from diffusing into non-working areas.

[0037] The radial actuation assembly includes a telescopic mechanism and a rigid rotation mechanism actuated by the telescopic mechanism. The telescopic structure includes a telescopic rod 115 located at the bottom of the outer shell 11, which can be implemented by an electric push rod. A push plate 114 is provided at the other end of the telescopic rod 115. The rigid rotation mechanism includes multiple rotating rods 112 and a push ball 113 corresponding to the number of rotating rods 112. The push ball 113 is located at the tail end of the rotating rod 112 and placed on the push plate 114. The upper edge of the push ball 113 contacts the bottom edge of the flexible contact shell 12.

[0038] The push plate 114 evenly distributes its force to multiple push balls 113, ensuring uniform force distribution to each rotating rod 112. The rotating rod 112 is hinged to the inner wall of the outer casing 11 via a lug plate 111 and a pin, providing a stable rotation fulcrum and eliminating the gaps and jamming that may occur with traditional sliding connections, resulting in a smooth rotation process. The upper edge of the push ball 113 contacts the bottom edge of the flexible contact shell 12; the arc-shaped transition design adapts to the slight undulations of the workpiece's bottom edge, thus maintaining stable transmission of the auxiliary clamping force during turning.

[0039] In this embodiment, a wire outlet hole and a heat sink are also provided on the outer casing 11. The wire outlet hole can realize the power-on and power-off operation of the locking unit, while the heat sink helps to maintain the thermal stability of the device during long-term operation.

[0040] This embodiment also discloses a machining method for a magnetorheological adaptive locking fixture 1 used in turning, including the following steps: S1. Workpiece clamping and initial positioning: Place the workpiece b to be processed in the inner cavity of the flexible contact shell 12. At this time, the magnetorheological liquid layer 14 is in a liquid flow state without being energized, the radial pushing component is in a retracted state, and the flexible contact shell 12 only provides a gentle wrapping of the workpiece without locking force. The operator can slightly adjust the workpiece to achieve accurate initial positioning.

[0041] S2, Composite Locking Sequence Start-up: An initial current is supplied to the excitation coil 16 of the axial locking assembly to generate a magnetic field, causing the magnetorheological liquid layer 14 surrounding the workpiece to undergo a solid-phase transformation from a liquid state to a near-solid state, thereby applying a uniform and adaptive main locking force to the workpiece through the flexible contact shell 12; this main locking force can automatically adapt to the small irregular shape of the workpiece surface, realizing an enveloping flexible locking of the upper part of the workpiece.

[0042] Subsequently, the telescopic mechanism of the radial push assembly is activated, driving the push plate 114 to move upward. By pushing the ball 113, multiple circumferentially distributed rotating rods 112 are lifted, causing the rotating rods 112 to rotate inward and upward around their hinge points, thereby applying a concentrated and rigid auxiliary clamping force from the bottom of the workpiece. This force works in conjunction with the main locking force to eliminate the radial degree of freedom of the workpiece and significantly enhance the workpiece's resistance to cutting overturning torque in the axial direction, forming a stable composite locking system with a flexible upper envelope and a rigid lower support.

[0043] S3. Adaptive Dynamic Locking and Turning: During turning, the cutting force, vibration signal, or preset machining parameters are monitored in real time; the current value of the input excitation coil 16 is dynamically adjusted, thereby steplessly and in real time adjusting the shear yield stress of the magnetorheological liquid layer 14, that is, adjusting the magnitude of the main locking force applied to the workpiece; when encountering heavy cutting or vibration tendency, the current is increased to enhance the locking force and ensure machining stability; when performing finishing or when the cutting force is small, the current is reduced to the minimum value to maintain locking, so as to reduce the internal stress introduced by the fixture and ensure machining accuracy; this process realizes online adaptive matching of locking force to machining state.

[0044] S4. Machining Completion and Locking Release: After the turning process is completed, the telescopic mechanism of the radial push assembly is first retracted, which drives the push plate 114 to move down. The rotating rod 112 opens outward under the action of gravity or the reset mechanism, releasing the auxiliary clamping force on the bottom of the workpiece. Then, the current of the excitation coil 16 is cut off, the magnetic field disappears, and the magnetorheological liquid layer 14 quickly recovers from a near-solid state to a liquid state, and the main locking force is completely released. Finally, the machined workpiece is taken out.

[0045] In summary, this invention employs a magnetorheological adaptive locking fixture and its machining method for turning, achieving high-precision, non-destructive adaptive locking of the workpiece and effectively suppressing clamping deformation of thin-walled and irregularly shaped parts. Through a combined mechanism of magnetorheological locking and mechanical rigid pushing, the dynamic stability of the machining process is significantly enhanced, while ensuring agile locking force response, low energy consumption, and long-term stable operation, thereby improving machining quality, efficiency, and fixture reliability.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A magnetorheological adaptive locking fixture for turning, disposed directly below the milling cutter and above the worktable, characterized in that, It includes a flexible contact shell that contacts the workpiece, a locking unit disposed at the outer end of the flexible contact shell, and an outer shell disposed outside the locking unit; The locking unit includes an axial locking assembly and a radial pushing assembly. The axial locking assembly is an adaptive locking assembly with an integrated magnetic circuit; the radial pushing assembly is a rigid pushing assembly.

2. The magnetorheological adaptive locking fixture for turning according to claim 1, characterized in that, The axial locking assembly includes a pole shoe, an excitation coil, a magnetorheological fluid layer, and an upper magnetic cover plate and a lower magnetic cover plate for forming a closed loop. The excitation coil is wound around the pole shoe, and the magnetorheological fluid layer is disposed in the gap formed by the excitation coil, the pole shoe, the upper magnetic cover plate, and the lower magnetic cover plate.

3. A magnetorheological adaptive locking fixture for turning according to claim 2, characterized in that, The pole shoe is a type I pole shoe, comprising a front pole tip, a pole body, and a rear pole tip arranged sequentially. Several pole shoes are provided, arranged symmetrically in a ring on the outside of the flexible contact shell. The front pole tip and the rear pole tip are arc-shaped plates with the same axis. The outer arc length of the front pole tip is smaller than the inner arc length of the rear pole tip. The front pole tip is located on the side closer to the flexible contact shell, and the rear pole tip is located on the side closer to the outer shell. The rear pole tip and the outer shell are connected by connecting protrusions.

4. A magnetorheological adaptive locking fixture for turning according to claim 2, characterized in that, The upper magnetic cover plate and the lower magnetic cover plate are any one of soft magnetic stainless steel, electrical pure iron or silicon steel sheet. The upper magnetic cover plate is connected to the outer shell by bolts. An insulating boss is provided inside the outer shell. The lower magnetic cover plate is placed on the insulating boss. The upper magnetic cover plate, the lower magnetic cover plate and the insulating boss are all provided with holes for the flexible contact shell to pass through.

5. A magnetorheological adaptive locking fixture for turning according to claim 3, characterized in that, The magnetorheological fluid layer is a flexible sealed bag containing magnetorheological fluid. The magnetorheological fluid layer undergoes a solid-phase transformation under the action of a magnetic field and transmits radial pressure to the flexible contact shell.

6. A magnetorheological adaptive locking fixture for turning according to claim 1, characterized in that, The radial actuation assembly includes a telescopic mechanism and a rigid rotation mechanism actuated by the telescopic mechanism.

7. A magnetorheological adaptive locking fixture for turning according to claim 6, characterized in that, The telescopic structure includes a telescopic rod disposed at the bottom of the outer shell, and a push plate disposed at the other end of the telescopic rod. The rigid rotation mechanism includes multiple rotating rods and a push ball corresponding to the number of rotating rods. The rotating rods are connected to the inner wall of the outer shell by a hinge consisting of an ear plate and a pin. The push ball is disposed at the tail end of the rotating rod and placed on the push plate. The upper edge of the push ball contacts the bottom edge of the flexible contact shell.

8. A magnetorheological adaptive locking fixture for turning according to claim 1, characterized in that, The outer casing has a wire outlet hole for powering on and off the locking unit, and a heat sink is also provided inside the outer casing.

9. A magnetorheological adaptive locking fixture for turning according to claim 2, characterized in that, When the excitation coil is energized, it forms a closed magnetic circuit. The path of the closed magnetic circuit is: rear pole tip - pole body - magnetorheological liquid layer - upper magnetic cover plate or lower magnetic cover plate - rear pole tip.

10. A machining method for a magnetorheological adaptive locking fixture for turning as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Workpiece clamping and initial positioning: The workpiece to be processed is placed in the inner cavity of the flexible contact shell. At this time, the magnetorheological liquid layer is in a liquid flow state without electricity, the radial pushing component is in a retracted state, and the flexible contact shell has no locking force on the workpiece. The operator can slightly adjust the workpiece to achieve accurate initial positioning. S2, Composite Locking Sequence Start-up: An initial current is passed through the excitation coil of the axial locking assembly to generate a magnetic field, causing the magnetorheological liquid layer surrounding the workpiece to undergo a solid-phase transformation from a liquid state to a near-solid state. A uniform and adaptive main locking force is applied to the workpiece through the flexible contact shell. This main locking force can automatically adapt to the small irregular shapes on the surface of the workpiece, realizing an enveloping flexible locking of the upper part of the workpiece. The telescopic mechanism of the radial pushing assembly is activated, driving the push plate to move upward. By pushing the ball, multiple circumferentially distributed rotating rods are lifted, causing the rotating rods to rotate inward and upward around their hinge points, applying a concentrated, rigid auxiliary clamping force from the bottom of the workpiece. S3. Adaptive dynamic locking and turning: During the turning process, the cutting force, vibration signal or preset machining condition parameters are monitored in real time; the current value input to the excitation coil is dynamically adjusted. S4. Machining Completion and Locking Release: After the turning process is completed, the telescopic mechanism of the radial push component is retracted, which drives the push plate to move down. The rotating rod opens outward under the action of gravity or the reset mechanism, releasing the auxiliary clamping force on the bottom of the workpiece. Subsequently, the current of the excitation coil is cut off, the magnetic field disappears, the magnetorheological liquid layer quickly recovers from a near-solid state to a liquid state, and the main locking force is completely released. The machined workpiece is then removed.

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