Reducing follow rest crankshaft slender shaft turning machine tool

Abstract

The invention relates to the technical field of crankshaft turning and discloses a variable-diameter follow rest crankshaft slender shaft turning machine tool which comprises a machine tool body and a follow rest, the follow rest comprises a fixing frame arranged on the side edge of the machine tool body, a lower positioning piece is fixedly connected to the side edge of the fixing frame, and an upper positioning piece attached to the lower positioning piece is arranged at the top end of the lower positioning piece. And the upper positioning piece and the lower positioning piece are closed to form a limiting ring. The limiting ring of the follow rest is a closed circular ring when the cutter does not move to the position nearby the limiting ring, the upper end of the limiting ring is exposed to form a space structure facilitating cutting of the cutter when the cutter moves to the position nearby the limiting ring, and compared with the structure that a shaft is not protected in all directions all the time, the upper end of the limiting ring always has an exposed space structure; the limiting ring is kept in a complete closed state, the supporting rigidity is high, and the structure can effectively restrain radial run-out of shaft parts during high-speed rotation and is particularly suitable for machining of slender shafts.

Description

Technical Field

[0001] This invention relates to the field of crankshaft turning technology, specifically to a machine tool for turning slender crankshafts with a variable diameter follow post. Background Technology

[0002] Specialized machine tools for machining slender crankshafts consist of a follow post, spindle system, feed system, tool post system, and tailstock. The slender crankshaft blank is clamped between the spindle and tailstock of the machine tool and secured firmly by a chuck or other clamping device. After the machine tool is started, the spindle drives the workpiece to rotate, and the follow post moves along the workpiece axially with the tool. The tool post system performs cutting motions according to program instructions to turn the workpiece, gradually machining the blank into the required slender crankshaft shape. The follow post is an auxiliary device used in lathe machining to radially support the rotating workpiece. This device provides continuous radial support by dynamically following the movement of the cutting tool to counteract the cutting force, preventing bending deformation and vibration of the workpiece due to excessive length-to-diameter ratio, thereby improving machining accuracy and surface quality.

[0003] When providing auxiliary support for variable-diameter shafts (such as crankshafts), the support structure of the follower post may be unable to fully adapt to abrupt changes or complex gradual changes in journal diameter due to design limitations or insufficient control precision. For example, when the journal diameter undergoes a step-like abrupt change or a continuous gradual change, mechanically linked follower posts are prone to support lag or interference due to mechanism stroke limitations. Hydraulic / pneumatic follower posts suffer from response delays caused by pressure-driven inertia, while CNC follower posts may experience detection blind spots or data processing lags due to insufficient sensor sampling frequency or unoptimized control algorithms. These technical bottlenecks will lead to problems such as abnormal support clearance, localized excessive compression, and high-frequency vibration, directly resulting in out-of-tolerance dimensional and positional tolerances such as roundness, cylindricity, and coaxiality of the machined workpiece, deterioration of surface roughness, increased tool wear, and reduced machining efficiency. In extreme cases, support failure during high-speed rotation can cause dynamic imbalance of the workpiece, and even equipment damage and safety accidents, severely restricting the high-precision and high-efficiency machining of complex variable-diameter shaft parts. Summary of the Invention

[0004] Technical problems to be solved In view of the above-mentioned shortcomings of the prior art, the present invention provides a turning machine tool for slender crankshafts with variable diameter follower post, which can effectively solve the problem that in the machining of variable diameter shafts in the prior art, the support structure of the follower post is unable to fully adapt to the sudden change or complex gradual change of the journal diameter due to design limitations or insufficient control precision.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a machine tool for turning slender crankshafts with variable diameter follower post, and a machine tool body; The tool follower includes a fixed frame disposed on the side of the machine tool body. A lower positioning component is fixedly connected to the side of the fixed frame. An upper positioning component is disposed at the top of the lower positioning component and fits therewith. The upper and lower positioning components close to form a limiting ring. The upper positioning component includes an upper module. One end of the upper module is hinged to a lower module through a hinge shaft. The upper module, the lower module, and the hinge shaft form a support block. The support block is symmetrically designed and interlocks with each other. The upper positioning component also includes an electromagnetic coil group disposed on the side of the lower module. The electromagnetic coil group moves along the surface of the lower module, causing the lower positioning component disposed below to unfold.

[0006] Furthermore, the upper module is smaller than the lower module, the distance between the upper modules is greater than the size of the cutting tool, and a rubber ball is rotatably connected to the inner wall of both the upper and lower modules.

[0007] Furthermore, a permanent magnet is fixedly connected to the top of the outer wall of the upper module. In the initial state, the permanent magnet and the electromagnetic coil group are not energized. When the gap between the tool and the upper module meets the set distance, the permanent magnet and the electromagnetic coil group are energized.

[0008] Furthermore, the lower module has a movable groove at the bottom of its outer wall, a sliding groove at the bottom of its inner wall, and a push plate with damping sliding on the inner wall of the sliding groove.

[0009] Furthermore, the push plate adopts a design that is larger at the top and smaller at the bottom, and a movable block is fixedly connected to the top of the push plate. The movable block is fixedly connected to one side of the electromagnetic coil assembly.

[0010] Furthermore, the lower positioning component includes a supporting bottom ring, with two rubber balls rotatably connected to the inner wall of the supporting bottom ring, and telescopic rods for connecting each other are equidistantly arranged on the side of the supporting bottom ring, and a limiting groove is opened on the supporting bottom ring at the position outside the telescopic rod to facilitate the insertion of the push plate.

[0011] Furthermore, in the initial state, the supporting bottom rings are fitted together under the constraint of the telescopic rod, and the minimum cavity size enclosed by the limiting groove is equal to the bottom size of the push plate.

[0012] The technical solution provided by this invention has the following advantages compared with the prior art: This invention features a follower post. The follower post's limiting ring is a closed loop when the tool is not near it, but becomes an exposed space at its upper end when the tool moves nearby, facilitating tool cutting. Compared to a structure where the shaft is never fully protected, the upper end of the limiting ring always has an exposed space, offering the following advantages: When the tool is not present, the limiting ring remains completely closed, forming a full-circumferential rigid constraint through 3 or 4-point support, resulting in high support stiffness. This structure effectively suppresses radial runout of shaft parts during high-speed rotation, making it particularly suitable for machining slender shafts (such as crankshaft journals). In contrast, the fixed exposed structure used in existing technologies is always open at the upper end, reducing the number of support points compared to the full-circumferential constraint structure, resulting in lower support stiffness and a higher risk of second-order bending vibration of the shaft system, causing ripples on the machined surface. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0014] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the tool holder structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the limiting ring structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the movable groove structure according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the electromagnetic coil assembly connection structure according to an embodiment of the present invention; Figure 6 This is a three-dimensional schematic diagram of the lower positioning component structure according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the separation structure of the lower positioning component according to an embodiment of the present invention.

[0015] The labels in the diagram represent: 1. Machine tool body; 2. Follow post; 21. Upper positioning component; 211. Upper module; 212. Lower module; 213. Hinge shaft; 214. Permanent magnet; 215. Electromagnetic coil assembly; 2151. Movable block; 2152. Push plate; 216. Rubber ball one; 217. Movable groove; 218. Slide groove; 22. Lower positioning component; 221. Support bottom ring; 223. Limiting groove; 225. Telescopic rod; 226. Rubber ball two; 23. Fixed frame. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] The present invention will be further described below with reference to embodiments. Example

[0018] Please see Figures 1-7 This invention provides a technical solution for a turning machine tool for slender crankshafts with variable diameter follow post: When the follower post 2 support point coincides with the turning area, if the strategy of "first releasing the limit, then machining, and finally re-limiting" is adopted, the secondary clamping will introduce positioning errors, leading to increased shaft vibration and excessive coaxiality. Furthermore, the machined non-circular outer surface (such as the eccentric journal of the crankshaft) cannot fully fit with the circular support surface of the follower post 2, easily resulting in localized suspension and weakening the support rigidity. If a dynamic support strategy of the follower post 2 following the tool's movement is adopted, it essentially involves adjusting the support position in real time to match the cutting area, but this strategy carries significant risks to dynamic stability. Due to the asymmetry of the crankshaft structure leading to uneven mass distribution, frequent axial offsets of the support points will cause dynamic deviations between the shaft system's inertial axis and rotation axis, triggering periodic centrifugal force fluctuations. Simultaneously, during the switching between old and new support points, the hydraulic or servo drive system has a response delay of 0.1–0.3 seconds, causing the support force to fail to compensate for changes in cutting force in a timely manner, resulting in shaft movement. The coupling effect of this dynamic imbalance and cutting force can easily induce regenerative chatter, causing chatter marks on the machined surface. In severe cases, it can lead to tool breakage and workpiece shape and position tolerance exceeding the tolerance, which greatly affects machining accuracy and production efficiency. In view of this, the present invention designs a follower post 2.

[0019] refer to Figure 1 , Figure 2 and Figure 3 The machine tool body 1 and the follower tool holder 2 are included. The follower tool holder 2 includes a fixed frame 23 set on the side of the machine tool body 1. A lower positioning member 22 is fixedly connected to the side of the fixed frame 23. An upper positioning member 21 is set at the top of the lower positioning member 22 and fits therewith. The upper positioning member 21 and the lower positioning member 22 close to form a limiting ring. The upper positioning member 21 includes an upper module 211. One end of the upper module 211 is hinged to a lower module 212 through a hinge shaft 213. The upper module 211, the lower module 212 and the hinge shaft 213 form a support block. The support block is symmetrically designed and interlocks with each other. The limiting ring of the tool holder 2 in this application is a closed ring when the tool is not near it, and becomes a structure with the upper end exposed to facilitate tool cutting when the tool moves near it. Compared with the structure that does not provide all-round protection for the shaft and always has an exposed space at the upper end of the limiting ring, it has the following advantages: When the tool is not reached, the limiting ring remains in a completely closed state, forming a full circumferential rigid constraint through 3 or 4-point support, with high support stiffness. This structure can effectively suppress the radial runout of shaft parts when rotating at high speed, and is especially suitable for machining slender shafts such as crankshaft main journals. In contrast, the fixed exposed structure used in the prior art has an open upper end. Compared with the full circumferential constraint, this structure has fewer support points, lower support stiffness, and is prone to second-order bending vibration of the shaft system, causing ripples on the machined surface. refer to Figure 4 and Figure 5 The upper positioning component 21 also includes an electromagnetic coil group 215 disposed on the side of the lower module 212. The electromagnetic coil group 215 moves along the surface of the lower module 212, causing the lower positioning component 22 to unfold. The size of the upper module 211 is smaller than that of the lower module 212, and the distance between the upper modules 211 is larger than the size of the tool. Rubber balls 216 are rotatably connected to the inner walls of both the upper module 211 and the lower module 212. A permanent magnet 214 is fixedly connected to the top of the outer wall of the upper module 211. In the initial state, the permanent magnet 214 and the electromagnetic coil group 215 are in contact with the upper module 212. When the coil assembly 215 is not energized, and the gap between the tool and the upper module 211 meets the set distance, the permanent magnet 214 and the electromagnetic coil assembly 215 are energized. The bottom of the outer wall of the lower module 212 is provided with a movable groove 217, and the bottom of the inner wall of the movable groove 217 is provided with a sliding groove 218. The inner wall of the sliding groove 218 is damped and slidably fitted with a push plate 2152. The push plate 2152 adopts a design that is larger at the top and smaller at the bottom. The top of the push plate 2152 is fixedly connected to a movable block 2151, and the movable block 2151 is fixedly connected to one side of the electromagnetic coil assembly 215.

[0020] When the tool cuts to the limiting ring area, the upper module 211 actively opens to avoid interference with the tool; it closes immediately after cutting, forming a new full-circumferential support for the machined surface. This "cut-as-you-go" characteristic reduces runout errors at diameter changes in the shaft system, such as the transition fillet between the crankshaft connecting rod journal and the main journal. In contrast, the open area of ​​a fixed exposed structure can never provide upper support for the machined surface, especially at abrupt changes in shaft diameter. The unsupported upper shaft section is prone to "swinging" due to centrifugal force, leading to coaxiality errors in subsequent machining.

[0021] The timing of the limit ring's opening is controlled by the CNC system to precisely match the tool feed trajectory. For example, the limit ring can be adjusted and opened 0.5 seconds before the tool arrives, based on the limit ring size and the tool feed direction, to avoid collision between the support block and the tool and reduce the risk of collision. In contrast, the fixed exposed structure, because its upper end is always open, requires a minimum safety clearance of ≥5mm between the support block and the tool, which forces the initial support position of the journal to be far away from the cutting area, thus failing to effectively suppress the "tool deflection" phenomenon during cutting.

[0022] In the closed state, the limiting ring forms a labyrinth seal with the shaft surface. Combined with the flushing effect of cutting fluid, this prevents most chips from entering the support area, avoiding hard particles such as alloy steel chips from embedding into the support block surface and causing scratches on the shaft surface. However, the opening at the top of the fixed exposed structure causes chips to easily accumulate in the gap between the support block and the shaft. Especially when machining tough materials, the entangled ribbon-like chips can jam the support block, causing localized overheating, which softens and deforms the nylon material of the support block, affecting machining accuracy.

[0023] When machining the eccentric crankshaft section, only the upper module is opened, while the left and right side modules remain supported. This further reduces shaft wobble errors during eccentric machining. Through independent control of the segmented modules, a composite state of "partial exposure + partial support" is achieved. In contrast, fixed exposed structures, due to their fixed opening direction, cannot adjust the support layout for the eccentric position, which easily leads to "insufficient support on one side" when machining the eccentric shaft, resulting in a larger eccentricity error after machining.

[0024] The dynamic opening and closing limit ring structure, through intelligent switching of "exposed during cutting and closed during non-cutting", is significantly superior to the fixed exposed structure in core indicators such as support rigidity, machining accuracy and tool protection. It is especially suitable for automated machining scenarios of long shafts, crankshafts and high-precision shafts.

[0025] In the initial state, the upper positioning component 21 of the overall closed support is closed. Four hinged sector blocks, under the action of preload springs or hydraulic pressure, are tightly assembled into a complete, continuous upper ring. Multiple 2-3 typically 180-degree arc-shaped limiting blocks fit tightly together, forming a complete, continuous lower positioning component 22. The arc-shaped rubber ball array embedded in its inner wall makes uniform contact with the shaft surface, providing preload and cushioning. Lateral limiting component retraction: The limiting protection device located on the side of the follower post 2 is in the retracted state and does not contact the shaft. Overall effect: The upper positioning component 21 and lower positioning component 22 together form a 360-degree, highly rigid, high-damping, continuously wrapped support ring. Only a small area at the top of the shaft is not in contact due to structural gaps, providing excellent static and dynamic stability to the shaft and resisting cutting vibration and deformation. The rubber balls evenly distribute pressure, protecting the surface.

[0026] Tool Approach: Triggering Avoidance Command When the tool moves to a set distance, for example, 150mm, from the support area of ​​the tool holder 2 under the control of the CNC program, the CNC system issues an avoidance action trigger signal. This signal simultaneously activates the hydraulic / pneumatic / servo electric drive system that controls the flipping of the upper positioning member 21, the extension of the lateral limiting member, and the separation of the lower positioning member 22.

[0027] Dynamic avoidance action: The zoned support mode activation action is completed collaboratively in an extremely short time (<0.2s): The upper positioning component 21 quickly flips and opens a window: Under the action of the drive mechanism, the four hinged sector blocks synchronously flip upwards by 90-120 degrees. Result: A spacious open window is formed above the shaft, providing an interference-free path for tool entry, cutting, and exit. At this time, the upper half of the shaft loses its direct support constraint.

[0028] Lateral limiting components extend precisely for protection: Almost simultaneously with the flipping of the upper module 211, the lateral limiting components, typically rigid wear-resistant blocks or adjustable ejector pins, extend rapidly and precisely from the side or rear of the follower post 2. The result: Its working end rigidly abuts against the finished surface of the shaft section that has been cut by the tool. This is equivalent to erecting a "protective wall" outside the completed critical area. Its core functions are: preventing vibration transmission: isolating vibrations generated in subsequent cutting areas from propagating to the completed area; resisting tool deformation: providing reverse support to resist the impact of overall shaft bending caused by forces in the new cutting area on the completed dimensions; and preventing accidental collisions: providing a physical barrier for the finished surface during rapid tool movement or reversal.

[0029] Lower Positioning Component 22 Separation and Positioning: Multiple 180-degree arc-shaped limiting blocks, originally integrated, separate axially under independent drive and are positioned as follows: Block A (Cutting Area Support Block): Located directly below or adjacent to the current tool cutting point. This block's support force is actively enhanced, such as through its built-in hydraulic chamber. Core Function: Concentrates superior "force" to provide the strongest local rigid support, directly counteracting the cutting radial force, minimizing instantaneous elastic deformation at the cutting point, and ensuring dimensional accuracy and surface quality in this area. Block B (Unfinished Area Pre-support Block): Moves to the front of the area to be cut by the tool, closer to the spindle direction. Core Function: Provides stable pre-support for the shaft segment that has not yet been machined but will soon bear cutting force, stabilizing the shaft segment, reducing its overhang length and pre-bending, creating stable conditions for the next tool entry, and reducing vibration and tool deflection risks from the source. Optional Block C: If the system includes a third block, it will be located further back or as a supplement to Blocks A / B, providing additional stability. Continuous function of the rubber balls: Even after the limiting blocks separate, the array of arc-shaped rubber balls on its inner wall continues to function, ensuring that the contact pressure between each individual limiting block and the shaft surface remains evenly distributed. This efficiently absorbs vibration energy generated within each zone. It adaptively compensates for shaft diameter tolerances and minor thermal expansion / bending deformation. It flexibly protects the shaft surfaces in all contact areas, especially machined surfaces, from scratches.

[0030] Cutting Process: Zoned coordination ensures the tool smoothly passes through the window opened by module 211 and enters the cutting area. Below the cutting point: Block A, the cutting area support block, provides reinforced, high-rigidity local support, while rubber balls absorb impact. This is the main battleground for ensuring cutting accuracy. Outside the machined area: Lateral limiting components act like "guardians," rigidly resisting the finished surface and ensuring it is protected from any disturbances from subsequent machining. Below the unmachined area: Block B, the pre-support block, provides stable pre-support, stabilizing the shaft segment to be cut. Overall Effect: Although the constraint of the upper half-circle is lost, through lateral rigid protection of the machined area + lower plate zoned reinforcement support of the cutting area + lower plate forward-looking pre-support of the unmachined area + rubber ball full-range buffering and adaptive protection, the system still achieves active, precise, and powerful protection and support for the entire length of the shaft segment, cutting segment, and unmachined segment in the avoidance state. This is incomparable to the traditional avoidance structure that simply opens the window, resulting in weakened or even missing support.

[0031] Cutting Completion and System Reset: When the tool completes cutting in the support area and moves a set distance away, the CNC system sends a reset signal. The upper positioning component 21 closes, and the upper sector block synchronously flips downward to reset, reassembling into a complete upper half-ring. The lateral limiting component retracts and quickly moves away from the shaft surface, removing the extra protection for the machined area. The separated 180-degree arc-shaped limiting blocks move precisely, re-fitting tightly against each other to reassemble into a complete, continuous lower positioning component 22. After all components have reset, the system reconstructs a 360-degree rigid, high-damping, continuously wrapped support ring, preparing for the next machining operation or the next obstacle avoidance maneuver.

[0032] refer to Figure 6 and Figure 7 The lower positioning component 22 includes a support bottom ring 221, with a rubber ball 226 rotatably connected to the inner wall of the support bottom ring 221. Telescopic rods 225 for connecting each other are equidistantly arranged on the side of the support bottom ring 221. A limiting groove 223 is opened on the support bottom ring 221 outside the telescopic rods 225 to facilitate the insertion of the push plate 2152. In the initial state, the support bottom rings 221 are in contact with each other under the restriction of the telescopic rods 225. The minimum cavity size enclosed by the limiting grooves 223 is equal to the bottom size of the push plate 2152.

[0033] As the cutting tool approaches the support area, the CNC system not only instructs the hinged sector block above to rotate upwards by an angle greater than 90 degrees and less than or equal to 120 degrees to expose the cutting space, but also simultaneously triggers two key actions: the extension of the lateral limiting component and the separation of multiple 180-degree arc-shaped limiting blocks of the lower positioning component 22 from each other. This signifies that the system instantly switches from the "overall wrapping support" mode to the "regional precise protection" mode.

[0034] The extended lateral stop precisely and rigidly abuts against the surface of the shaft section that has already been cut by the tool. This is equivalent to adding an extra "bumper" to the most vulnerable and precision-required machined surface at the moment of avoidance. It effectively prevents damage to the finished surface from vibrations, tool deflection, or accidental collisions caused by the tool entering a new area, ensuring the absolute safety of critical dimensions and surface quality. This level of protection is completely unavailable in traditional structures during avoidance, achieving seamless protection and reinforcement of the machined area.

[0035] Meanwhile, multiple 180-degree arc-shaped limiting blocks, originally forming a complete lower support surface, separate under control, increasing their supporting force and concentrating more resources on the area bearing the main cutting force. This characteristic of "dynamic concentration of supporting force" significantly enhances the local rigidity near the cutting point, effectively resists instantaneous deformation caused by cutting force, improves the dimensional accuracy and surface quality of the cutting process, allows for more stable cutting parameters, and dynamically concentrates and strengthens the supporting force in the cutting area.

[0036] In the separated lower positioning block, the limiting block located in front of the area to be cut moves to the appropriate position, providing pre-emptive and stable support for the shaft segment that has not yet been machined but will soon bear the cutting force. This "proactive support" stabilizes the shaft in the area to be machined, reduces pre-bending caused by overhang or insufficient support, creates a more stable and predictable working condition for subsequent tool entry, reduces the risk of tool deflection and vibration from the source, and provides pre-support and stability assurance for the area to be cut.

[0037] All lower positioning blocks employ a 180-degree arc-shaped semi-circular support plate design, with a precisely arranged array of arc-shaped rubber balls on their inner wall. The rubber balls evenly distribute contact pressure, ensuring uniform pressure distribution between each positioning block and the shaft surface even when the limiting blocks are separated, preventing stress concentration. This not only continuously absorbs vibration energy from the cutting zone and the entire shaft system, ensuring the stability of each support zone, but also allows the rubber's elasticity to automatically compensate for minor changes in shaft diameter and thermal expansion, maintaining stable and effective contact without frequent manual intervention. The flexible contact prevents scratches on the precision-machined surface.

[0038] The entire system's hydraulic / pneumatic / electric servo drives and position controls, such as magnetic encoder feedback, for the flipping of module 211, the extension / retraction of the side limiters, and the separation / convergence of the lower positioning blocks are precisely coordinated. Its response speed is fast enough to ensure mode switching is completed before the tool arrives. More importantly, as the tool leaves and the upper module 211 closes and resets, the side limiters retract precisely, and the lower positioning blocks accurately reset to their initial tightly coupled state. This ensures that during non-avoidance periods, the system returns to a strong overall support ring with extremely high reset accuracy, without affecting overall rigidity.

[0039] Through the "ironclad protection" of lateral limiting components and the "precise force application" of zoned supports, the machined precision is protected to the greatest extent, improving machining accuracy and significantly enhancing roundness, cylindricity, and surface quality, especially during finish turning and interrupted cutting. The strengthened support force at the cutting point allows for more aggressive cutting parameters without instability, improving efficiency; zoned pre-support reduces machine setup time. Zoned support distributes the load, reducing stress on individual components; rubber balls continuously protect the shaft surface; multiple lateral and vertical limiting components provide redundant safety. It is particularly suitable for turning complex, slender shafts with extremely high length-to-diameter ratios, stringent precision requirements, and interrupted cutting processes, such as crankshaft connecting rod journals, camshafts, or surfaces where machined surfaces are easily damaged.

[0040] In summary, "dynamic zone support" differs from traditional structures, which are limited to passively weakening support or having no protection at all when the tool avoids it. Through an intelligent "zoned limiting and force following the tool" mechanism, extending a lateral "shield" to protect the workpiece, separating the lower "heavy troops" to focus on the front line, reserving a "vanguard" to stabilize the rear, and using rubber "soft armor" for buffering and pressure adjustment, it achieves active, precise, and powerful protection and support for the machined area, cutting area, and unprocessed area of ​​the workpiece during dynamic avoidance, raising the machining accuracy, stability, and efficiency to a whole new level.

[0041] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A machine tool for turning slender crankshafts with variable diameter and follow post, characterized in that, include: Machine tool body (1); The tool holder (2) includes a fixed frame (23) set on the side of the machine tool body (1). A lower positioning member (22) is fixedly connected to the side of the fixed frame (23). An upper positioning member (21) is provided at the top of the lower positioning member (22) and fits therewith. The upper positioning member (21) and the lower positioning member (22) close to form a limiting ring. The upper positioning member (21) includes an upper module (211). One end of the upper module (211) is hinged to a lower module (212) through a hinge shaft (213). The upper module (211), the lower module (212) and the hinge shaft (213) form a support block. The support block is symmetrically designed and interlocks with each other. The upper positioning member (21) also includes an electromagnetic coil group (215) disposed on the side of the lower module (212). The electromagnetic coil group (215) moves along the surface of the lower module (212), causing the lower positioning member (22) disposed below to unfold.

2. The variable diameter follower crankshaft slender shaft turning machine tool according to claim 1, characterized in that: The upper module (211) is smaller than the lower module (212), the distance between the upper modules (211) is greater than the size of the cutting tool, and a rubber ball (216) is rotatably connected to the inner wall of both the upper module (211) and the lower module (212).

3. The variable diameter follower crankshaft slender shaft turning machine tool according to claim 2, characterized in that: A permanent magnet (214) is fixedly connected to the top of the outer wall of the upper module (211). In the initial state, the permanent magnet (214) and the electromagnetic coil group (215) are not energized. When the gap between the tool and the upper module (211) meets the set distance, the permanent magnet (214) and the electromagnetic coil group (215) are energized.

4. The variable diameter follower crankshaft slender shaft turning machine tool according to claim 3, characterized in that: The lower module (212) has a movable groove (217) at the bottom of its outer wall, and a sliding groove (218) at the bottom of its inner wall. A push plate (2152) is provided on the inner wall of the sliding groove (218) for damping sliding.

5. A variable diameter follower crankshaft slender shaft turning machine tool according to claim 4, characterized in that: The push plate (2152) adopts a design that is larger at the top and smaller at the bottom. A movable block (2151) is fixedly connected to the top of the push plate (2152), and the movable block (2151) is fixedly connected to one side of the electromagnetic coil group (215).

6. A variable diameter follower crankshaft slender shaft turning machine tool according to claim 5, characterized in that: The lower positioning component (22) includes a support bottom ring (221), and a rubber ball (226) is rotatably connected to the inner wall of the support bottom ring (221). Telescopic rods (225) for connecting each other are equidistantly arranged on the side of the support bottom ring (221). A limiting groove (223) is opened on the support bottom ring (221) at the position outside the telescopic rod (225) to facilitate the insertion of the push plate (2152).

7. A variable diameter follower crankshaft slender shaft turning machine tool according to claim 6, characterized in that: In the initial state, the support bottom ring (221) is in contact with each other under the restriction of the telescopic rod (225), and the minimum cavity size enclosed by the limiting groove (223) is equal to the bottom size of the push plate (2152).

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