A trimming device in the tire forming process

Abstract

This utility model provides a trimming device for tire forming process, belonging to the technical field of trimming devices. The trimming device includes: a fixed frame; a floating main shaft horizontally mounted on the fixed frame, the floating main shaft reciprocating along its own axis only under the thrust of the tire blank end face; a pair of ball screw nut pairs, respectively arranged at both ends of the floating main shaft, with opposite helical directions; two sets of symmetrical tool holders, each set of tool holders connected to the end of the floating main shaft via a corresponding ball screw nut pair; an arc-shaped guide groove formed on the fixed frame and located below the tool holder; rollers installed at the bottom of the tool holder and rollingly engaging with the arc-shaped guide groove; and trimming cutters fixed to the side of the tool holder facing the tire blank end face. This invention solves the technical problem that tire blanks require multiple clamping operations during forming to trim both ends, and cannot adapt to fluctuations in tire blank diameter, leading to unstable trimming quality.

Description

Technical Field

[0001] This utility model belongs to the technical field of trimming devices, specifically, it relates to a trimming device in the tire forming process. Background Technology

[0002] In the single or double forming process of radial tires, after the belt layer, tread, and sidewall are bonded together, irregular excess rubber often remains at both ends of the tire carcass due to material overlap or cutting errors. If this excess rubber enters the vulcanizing mold directly, it will flow and overflow from the parting surface under high temperature and pressure, causing defects in the tire bead appearance, poor dynamic balance, and even affecting the mold seal. Therefore, before the tire carcass enters the vulcanizing process, a trimming device must be used to circumferentially cut the two end faces to ensure a smooth transition with the tire carcass contour.

[0003] In existing technologies, common tire trimming devices can be broadly categorized into two types: one involves a manually operated pneumatic trimming blade, where the operator walks around the rotating tire blank and cuts segment by segment; the other uses a fixed blade holder on a forming drum or auxiliary turntable, with adjustable blades mounted on the holder, and the blade tip is fed radially via a manual or electric screw. Both methods rely on the operator's experience to judge the depth of cut, and trimming at both ends must be done in steps: trim one end first, stop the machine, re-clamp or move the blade holder, and then trim the other end. Multiple clamping increases auxiliary time and can easily lead to uneven allowance at both ends due to positioning errors. Furthermore, traditional blade holders are mostly rigidly connected. When the tire blank diameter fluctuates slightly due to batch differences in materials or changes in bulging, the contact pressure between the blade and the tire tread changes accordingly. This can result in minor issues like "biting" or "missed trimming" on the trimmed surface, or even blade chipping and tire blank failure. Due to the aforementioned drawbacks, traditional trimming devices cannot meet the demands of modern tire manufacturing, which requires large-scale production, high precision, and low loss. There is an urgent need for a floating bidirectional synchronous trimming device that can simultaneously trim both ends of the tire blank in a single clamping operation and can adapt to changes in diameter. Utility Model Content

[0004] In view of this, the present invention provides a trimming device for the tire forming process, which solves the technical problem that the tire blank needs to be clamped multiple times during the forming process to trim the two ends, and cannot adapt to the fluctuation of the tire blank diameter, resulting in unstable trimming quality.

[0005] This utility model is implemented as follows: This utility model provides a trimming device in the tire forming process, comprising: Fixed frame; A floating spindle is horizontally mounted on the fixed frame. The floating spindle can reciprocate along its own axis only under the thrust of the end face of the tire blank. A pair of ball screw nuts are respectively arranged at both ends of the floating spindle, and their helical directions are opposite; Two sets of symmetrical tool holders, each set of tool holders is connected to the end of the floating spindle through a corresponding ball screw nut pair, so that the axial floating of the floating spindle is converted into the synchronous radial approach or departure of the two sets of tool holders; An arc-shaped guide groove is formed in the fixed frame and located below the tool holder; A roller is installed at the bottom of the tool holder and rolls in cooperation with the arc-shaped guide groove to limit the movement trajectory of the tool holder; The trimming tool is fixed to the side of the tool holder facing the end face of the blank; The floating spindle, ball screw nut pair, tool holder, roller and arc guide groove together form a linkage mechanism, so that when the tire blank rotates, the trimming tool always maintains a constant contact pressure with the two end faces of the tire blank, realizing bidirectional synchronous trimming in one clamping.

[0006] The technical effects of the trimming device in the tire forming process provided by this utility model are as follows: When the tire blank rotates, the two ends of the tire blank directly push the floating spindle to generate axial floating. This floating is simultaneously converted into the synchronous radial feed or retraction of two sets of tool holders through the reverse spiral ball screw-nut pair. The rolling cooperation between the roller and the arc-shaped guide groove ensures that the motion trajectory is always consistent with the contour of the tire blank end face. Thus, in the entire trimming process, the trimming tool is pressed against the two ends of the tire blank with constant pressure, realizing bidirectional synchronous removal of excess rubber in one clamping, significantly reducing end face waves and manual adjustment time, and improving end face flatness and production efficiency.

[0007] Based on the above technical solution, the trimming device in the tire forming process of this utility model can be further improved as follows: The floating spindle is supported on the fixed frame by a sliding bearing. The axial length of the sliding bearing is less than the axial floating stroke of the floating spindle, so as to allow the floating spindle to float freely.

[0008] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the floating spindle is supported by a sliding bearing and the bearing length is less than its floating stroke, so that the spindle can float freely in the axial direction while maintaining radial positioning. This avoids jamming and ensures real-time response to the thrust of the blank end face, further improving the stability of the trimming pressure and the reliability of the device.

[0009] Furthermore, the screw in the ball screw nut assembly is coaxially fixed to the floating spindle, and the nut is rigidly connected to the corresponding tool holder, so that the axial displacement of the floating spindle directly drives the tool holder to move radially along the arc-shaped guide groove.

[0010] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the arrangement of the lead screw and the floating spindle being coaxially fixed and the nut and the tool post being rigidly connected allows the axial displacement of the spindle to be directly and instantly converted into the radial displacement of the tool post, eliminating intermediate transmission links, reducing cumulative backlash and energy loss, and ensuring higher synchronization accuracy of the tool posts at both ends and more consistent trimming depth.

[0011] Furthermore, the curvature center of the arc-shaped guide groove coincides with the rotation axis of the tire blank, so as to ensure that the cutting trajectory of the trimming tool matches the end face contour of the tire blank.

[0012] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the curvature center of the arc-shaped guide groove coincides with the rotation axis of the tire blank, so that the movement trajectory of the tool holder is always concentric with the theoretical contour of the tire blank end face, eliminating the overcutting or undercutting phenomenon caused by trajectory deviation, and ensuring that the end face after trimming is a regular circle and does not require secondary trimming.

[0013] Furthermore, the roller is mounted on the bottom of the tool holder via an eccentric shaft, and the gap between the roller and the arc-shaped guide groove can be finely adjusted by rotating the eccentric shaft.

[0014] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the roller is installed at the bottom of the tool holder through the eccentric shaft, and the gap between the roller and the guide groove can be finely adjusted by rotating the eccentric shaft without disassembling any parts, thereby quickly compensating for positional errors after wear or tool replacement, extending the equipment maintenance cycle and reducing downtime.

[0015] Furthermore, the tool holder is generally L-shaped, with its vertical section fixedly connected to the nut of the ball screw nut pair, the trimming tool installed at the end of the horizontal section, and the roller provided below the horizontal section.

[0016] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the L-shaped tool holder fixes the vertical section to the nut and the horizontal section carries the tool and roller, so that the axial thrust of the ball screw-nut pair and the radial reaction force of the roller are balanced in the same plane, which significantly reduces the bending moment and vibration of the tool holder and improves the tool life and cutting surface quality.

[0017] Furthermore, the trimming tool is detachably connected to the tool holder via a dovetail groove, so that the cutting edge of the tool is perpendicular to the end face of the blank.

[0018] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the trimming tool is detachably connected to the tool holder through the dovetail groove, and the cutting edge of the tool is perpendicular to the end face of the blank, which ensures the stability of the cutting force direction and facilitates quick tool replacement, reducing the time for resetting the tool due to tool replacement. At the same time, the dovetail groove structure provides reliable positioning accuracy and prevents the tool from loosening during the cutting process.

[0019] Furthermore, the fixed frame is also equipped with a dust cover, which covers the ball screw nut pair and the arc-shaped guide groove to prevent adhesive debris from entering the moving pair.

[0020] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the dust cover covers the ball screw-nut pair and the arc-shaped guide groove, effectively preventing rubber debris and dust from entering the precision moving pair, reducing wear and jamming risks, extending the service life of the ball screw and rollers, reducing the frequency of daily maintenance, and improving the continuous operation capability of the equipment.

[0021] Furthermore, elastic buffers are provided at both ends of the floating spindle. One end of the elastic buffer abuts against the fixed frame, and the other end abuts against the end of the floating spindle, for absorbing axial impact.

[0022] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: elastic buffers are set at both ends of the floating spindle, which can absorb axial impact when the thrust on the end face of the blank changes suddenly, prevent the spindle and the ball screw-nut pair from being subjected to rigid impact, reduce vibration and noise, and improve the overall machine operation stability and operational safety.

[0023] Furthermore, the cross-section of the arc-shaped guide groove is "V" shaped, and the outer circumferential surface of the roller is provided with a tapered profile that matches the "V" shaped groove to prevent the roller from lateral movement during operation.

[0024] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the V-shaped guide groove matches the contour of the tapered roller, forming a self-centering effect, automatically correcting the lateral deviation that may occur during the operation of the roller, ensuring that the tool holder always maintains a precise radial movement trajectory, thereby improving the trimming accuracy and repeatability accuracy, and reducing the scrap rate caused by roller deviation.

[0025] Compared with existing technologies, the advantages of the trimming device in the tire forming process provided by this utility model are as follows: This utility model, through the linkage design of a horizontal floating spindle, a double ball screw-nut pair with opposite helical directions, an arc-shaped guide groove, and a roller-tool holder, converts the rotational kinetic energy of the tire blank itself into the synchronous radial feed power of the tool holder. When the end face of the tire blank pushes the floating spindle, the axial floating of the spindle is immediately amplified by the opposing ball screw-nut pairs at both ends into the radial displacement of the tool holder. Under the constraint of the arc-shaped guide groove, the tool holder always moves along the contour of the end face of the tire blank, and the trimming tool adheres to the tire tread with constant pressure. The entire trimming process requires no manual intervention. Since the tool holders at both ends are driven by the same floating spindle, their feed amounts always remain symmetrical, fundamentally eliminating the positioning errors caused by traditional step-by-step trimming. At the same time, the elastic floating capability of the floating spindle enables the device to compensate for small changes in the tire blank diameter in real time, avoiding the "overcutting" or "undercutting" phenomenon of the rigid tool holder, and significantly improving the flatness of the finished product end face. Furthermore, the device employs a purely mechanical linkage, requiring no additional motors, sensors, or control programs. Its simple and reliable structure results in low maintenance costs. The "L"-shaped layout of the tool holder and the dovetail quick-change structure further shorten tool changing and specification switching time, making production line changeovers more flexible. Overall, while ensuring trimming quality, the device simplifies the complex process of traditional two clamping and multiple adjustments into a single clamping and rotation action, significantly reducing auxiliary time, labor intensity, and scrap rate. It provides an efficient, stable, and low-loss trimming solution for tire forming processes. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is an example diagram of a trimming device used in the tire forming process; Figure 2 A side view of a trimming device used in the tire forming process; Figure 3 A top view of a trimming device used in the tire forming process; The attached diagram lists the components represented by each number as follows: 10. Fixed frame; 11. Arc-shaped guide groove; 12. Roller; 20. Floating spindle; 30. Ball screw nut pair; 40. Tool holder; 41. Trimming tool. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0029] like Figures 1-3 The diagram shown is an example of a trimming device used in the tire forming process according to this utility model, comprising: Fixed frame 10; A floating spindle 20 is horizontally set on a fixed frame 10. The floating spindle 20 can reciprocate along its own axis only under the thrust of the end face of the tire blank. A pair of ball screw nut pairs 30 are respectively arranged at both ends of the floating spindle 20, and their helical directions are opposite; Two sets of symmetrical tool holders 40, each set of tool holders 40 is connected to the end of the floating spindle 20 through a corresponding ball screw nut pair 30, so that the axial floating of the floating spindle 20 is converted into the synchronous radial approach or departure of the two sets of tool holders 40. An arc-shaped guide groove 11 is formed in the fixed frame 10 and located below the tool holder 40; Roller 12 is installed at the bottom of tool holder 40 and rolls in engagement with arc-shaped guide groove 11 to limit the movement trajectory of tool holder 40; The trimming tool 41 is fixed to the side of the tool holder 40 facing the end face of the blank; The floating spindle 20, ball screw nut pair 30, tool holder 40, roller 12 and arc-shaped guide groove 11 together form a linkage mechanism, so that when the tire blank rotates, the trimming tool 41 always maintains a constant contact pressure with the two end faces of the tire blank, realizing bidirectional synchronous trimming in one clamping.

[0030] In the above technical solution, the floating spindle 20 is supported on the fixed frame 10 by a sliding bearing. The axial length of the sliding bearing is less than the axial floating stroke of the floating spindle 20, so as to allow the floating spindle 20 to float freely.

[0031] The lead screw on the left is "welded" to the left end of the floating spindle, with a left-hand thread; the lead screw on the right is "welded" to the right end of the floating spindle, with a right-hand thread. The lead screw and the floating spindle are in a straight line, and the nut is fitted onto the lead screw. When the floating spindle slides left or right, the nut is forced to move forward or backward along the thread.

[0032] Furthermore, in the above technical solution, the screw in the ball screw nut assembly 30 is coaxially fixed to the floating spindle 20, and the nut is rigidly connected to the corresponding tool holder, so that the axial displacement of the floating spindle 20 directly drives the tool holder to move radially along the arc-shaped guide groove 11.

[0033] Each end of the floating spindle is machined with a short external thread shaft. After the short external thread shaft is screwed into the blind hole of the internal thread at the tail end of the lead screw, a set screw is inserted radially to lock it in place. At the same time, splines that mesh with each other are opened on the mating end faces of the lead screw and the floating spindle. After the splines mesh, they are axially pressed with a round nut to achieve dual fixation of torque transmission and axial positioning, ensuring that the lead screw and the floating spindle have neither relative rotation nor axial movement.

[0034] A rectangular countersunk plate, matching the outer contour of the nut, is milled on the end face of the vertical section of the tool holder. The nut is then embedded in the countersunk plate and fits flatly. Four through holes are made around the countersunk plate, and threaded holes are machined at corresponding positions on the outer periphery of the nut. The nut is then tightened to the vertical section of the tool holder using high-strength internal hexagon screws. At the same time, a locating pin hole is machined at the bottom of the countersunk plate, and a cylindrical pin is pressed in to form radial positioning, preventing the nut from rotating slightly when subjected to helical thrust, and ensuring that the tool holder and the nut form an integral rigid structure.

[0035] Furthermore, in the above technical solution, the curvature center of the arc-shaped guide groove 11 coincides with the rotation axis of the tire blank, so as to ensure that the cutting trajectory of the trimming tool 41 matches the end face contour of the tire blank.

[0036] Furthermore, in the above technical solution, the roller 12 is mounted on the bottom of the tool holder 40 via an eccentric shaft, and the gap between the roller 12 and the arc-shaped guide groove 11 can be finely adjusted by rotating the eccentric shaft.

[0037] Furthermore, in the above technical solution, the tool holder 40 is generally L-shaped, its vertical section is fixedly connected to the nut of the ball screw nut pair 30, the end of the horizontal section is equipped with a trimming tool 41, and a roller 12 is provided below the horizontal section.

[0038] Furthermore, in the above technical solution, the trimming tool 41 is detachably connected to the tool holder 40 through a dovetail groove, so that the cutting edge of the tool is perpendicular to the end face of the blank.

[0039] The tool mounting surface of the horizontal section of the tool holder is milled with an outward-expanding dovetail guide rail, which extends to the edge at both ends. The back of the trimming tool is integrally cast with an inward-retracting dovetail slider. After the slider is inserted from one end of the guide rail, the axial displacement of the slider is restricted by a stop screw screw screwed into the end face. A spring ball is added to the bottom of the dovetail guide rail, and a hemispherical recess is opened at the corresponding position of the slider. The ball is embedded in the recess to achieve quick positioning and pre-tightening. The tool can be pulled out along the guide rail direction to complete the replacement without disassembling other parts.

[0040] Furthermore, in the above technical solution, the fixed frame 10 is also provided with a dust cover, which covers the ball screw nut pair 30 and the arc-shaped guide groove 11 to prevent adhesive debris from entering the moving pair.

[0041] Furthermore, in the above technical solution, elastic buffers are provided at both ends of the floating spindle 20. One end of the elastic buffer abuts against the fixed frame 10, and the other end abuts against the end of the floating spindle 20, for absorbing axial impact.

[0042] The elastic cushioning element is shaped like two "springs" or "rubber pads," similar to sofa springs. It fits around both ends of the floating spindle, with one spring resting against the end face of the spindle and the other against the outer edge of the table. It is tightened with nuts, normally keeping the floating spindle in the center position. When the dough pushes the spindle from side to side, the springs are compressed or stretched, absorbing the impact and preventing hard collisions.

[0043] Furthermore, in the above technical solution, the cross-section of the arc-shaped guide groove 11 is "V" shaped, and the outer peripheral surface of the roller 12 is provided with a conical profile that matches the "V" shaped groove, so as to prevent the roller 12 from moving laterally during movement.

[0044] First embodiment: In a forming section producing 3 million semi-steel radial tires annually, the tire blanks range in diameter from approximately 750 mm to 600 mm, with frequent specification changes. Traditional two-clamp trimming methods are no longer sufficient to meet the cycle time requirements. This embodiment employs a fixed frame arranged horizontally, with a floating spindle mounted in the center of the frame via a pair of copper-based sliding bearing seats. The axial floating stroke is limited within a reasonable range by the length of the bearing seats. Reverse trapezoidal external threads are machined at both ends of the spindle, directly screwed into two ball screws and locked with radial set screws. A rectangular boss is milled on the outside of the nut, embedding into the rectangular countersunk of the vertical section of the "L"-shaped tool holder, and then rigidly connected with four high-strength hexagonal socket screws and two cylindrical pins. A dovetail guide rail is milled at the front end of the horizontal section of the tool holder. After the dovetail slider on the back of the trimming tool is inserted, it is limited by an end-face stop screw, ensuring the cutting edge of the blade is perpendicular to the end face of the tire blank. Rollers are mounted below the horizontal section via an eccentric shaft, rolling within an arc-shaped guide groove at a corresponding position on the frame. The center of curvature of the guide groove coincides with the center of rotation of the tire blank.

[0045] Operating Procedure: The tire blank is fed to the turntable and clamped for rotation, with both end faces initially contacting the cutting blade. The thrust from the tire blank's end faces pushes the floating spindle to move slightly axially. The reverse lead screw converts this displacement into an equal but reverse radial synchronous feed of the two nuts. The tool holder, constrained by the arc-shaped guide groove, always cuts along the tire blank's contour. Because the tool holder is driven by the same spindle, the allowances at both ends remain symmetrical. When the diameter increases due to material tolerances, the spindle is further pushed away from the center, and the tool holder retracts synchronously, automatically reducing the depth of cut. Conversely, when the diameter decreases, the spindle moves further away, achieving adaptive trimming. The entire trimming process requires no machine stoppage for adjustment and no additional power.

[0046] Semi-steel radial tire forming lines operate in a continuous production environment with a wide range of specifications, frequent switching, and high cycle time requirements.

[0047] The device completes the trimming of both ends in one clamping, eliminating multiple positioning errors; the combination of the floating spindle and the reverse lead screw enables the device to compensate for diameter fluctuations in real time, resulting in a uniform trimming surface without scratches; the pure mechanical linkage eliminates the need for an electrical control system, simplifying maintenance, shortening tool change time, and meeting the requirements of high-speed continuous operation.

[0048] Second embodiment: In a flexible molding section primarily producing large engineering tires, the tire blanks can reach a diameter of two meters, are heavy, and have thick, uneven residual adhesive on the end faces, requiring extremely high stability in trimming depth. This embodiment still uses the structure within the scope of the same claim, but to accommodate greater loads, a spline sleeve structure is added between the floating spindle and the ball screw: spline teeth are machined at both ends of the spindle, and an internal spline hole is correspondingly opened at the tail end of the screw. After the two are inserted, they are axially pressed together with a round nut, which transmits greater torque and allows axial slippage, effectively avoiding impact damage caused by large-diameter tire blanks. The guide groove is changed to a double "V" shaped cross section, and the outer circumference of the roller is machined into a matching double conical surface, enhancing self-centering ability; in addition to the original screw-pin connection between the vertical section of the tool holder and the nut, a reinforcing rib is welded to improve bending stiffness.

[0049] Operating Procedures: The giant tool holder is hoisted onto the drum and rotates at low speed. Upon contact with the blades at both ends, its large mass and inertia generate a correspondingly increased axial thrust. This thrust is transmitted to the reverse lead screw via the spline sleeve, driving the two tool holders to feed radially synchronously. Double "V"-shaped guide grooves and double conical rollers ensure that the tool holders do not sway laterally under heavy loads. The spline sleeve allows the spindle to slip slightly upon impact to absorb energy and protect the lead screw from instantaneous overload. After trimming, loosening the stop screw allows the dovetail slide to be pulled out for blade replacement without disassembling the entire tool holder.

[0050] Flexible production lines for engineering giant tires or small-batch, multi-specification giant tires, characterized by large tire blank weight, thick residual rubber on the end face, and high impact load.

[0051] The design of the spline sleeve and reinforcing ribs enables the device to withstand the impact and bending moment brought by the giant tire, while maintaining bidirectional synchronous accuracy and adaptive compensation; the double "V" shaped guide structure improves the stability of heavy-load operation, the trimming depth is uniform, and the blade life is extended; the structure is still within the scope of the claims, and can achieve efficient trimming of giant tires without electrical control, significantly reducing manual intervention and scrap rate.

[0052] Specifically, the principle of this utility model is as follows: The core of this utility model lies in the three-in-one motion conversion and force balance system of "floating spindle - reverse lead screw - synchronous tool holder". The floating spindle is supported on the fixed frame by sliding bearings and can float freely in the axial direction; its two ends are respectively fixed with ball screws with opposite helical directions, and nuts are fitted on the lead screws, which are rigidly connected to the tool holder. When the blank rotates, the cutting force between the blank end face and the trimming tool forms an axial thrust, which pushes the floating spindle to move along the axis; since the helical directions of the two lead screws are opposite, the same axial displacement produces angular displacements of equal magnitude and opposite direction at both ends, thereby driving the two nuts to move simultaneously centripetally or centrifugally, and thus driving the tool holder to feed or retract synchronously radially along the arc-shaped guide groove. The curvature center of the arc-shaped guide groove coincides with the rotation axis of the blank, ensuring that the motion trajectory of the tool holder is always concentric with the theoretical contour of the blank end face, so that the blade maintains a constant cutting depth throughout the circumferential cutting process; The bottom of the tool holder is equipped with rollers that roll in conjunction with an arc-shaped guide groove. This serves two purposes: firstly, it transfers the tool holder's own weight and cutting reaction force to the machine frame, reducing the radial load on the leadscrew-nut pair and improving transmission accuracy and lifespan; secondly, it utilizes rolling friction instead of sliding friction, reducing motion resistance and allowing even slight spindle movement to be sensitively converted into radial displacement of the tool holder. Adjusting the gap between the rollers and the guide groove via an eccentric shaft compensates for wear on the rollers or guide groove without disassembling any components, maintaining long-term accuracy. From a mechanical perspective, this invention forms an adaptive force closed loop: the end face of the tire blank pushes the spindle to generate axial displacement → the reverse screw converts the axial displacement into radial feed → the radial displacement of the tool holder changes the cutting depth of the blade → the change in cutting depth, in turn, adjusts the magnitude of the end face thrust. When the tire blank diameter is slightly larger, the cutting depth of the blade increases, and the end face thrust increases accordingly, pushing the spindle to float further axially, the tool holder to retract radially, and the cutting depth to automatically decrease; the reverse is also true. This negative feedback mechanism keeps the system tending towards a balanced state, ensuring that the blade cuts with a near-constant pressure, thereby achieving consistent trimming quality on tire blanks of different batches and diameters.

Claims

1. A trimming device for tire forming process, characterized in that, include: Fixed frame; A floating spindle is horizontally mounted on the fixed frame. The floating spindle can reciprocate along its own axis only under the thrust of the end face of the tire blank. A pair of ball screw nuts are respectively arranged at both ends of the floating spindle, and their helical directions are opposite; Two sets of symmetrical tool holders, each set of tool holders is connected to the end of the floating spindle through a corresponding ball screw nut pair, so that the axial floating of the floating spindle is converted into the synchronous radial approach or departure of the two sets of tool holders; An arc-shaped guide groove is formed in the fixed frame and located below the tool holder; A roller is installed at the bottom of the tool holder and rolls in cooperation with the arc-shaped guide groove to limit the movement trajectory of the tool holder; The trimming tool is fixed to the side of the tool holder facing the end face of the blank; The floating spindle, ball screw nut pair, tool holder, roller and arc guide groove together form a linkage mechanism, so that when the tire blank rotates, the trimming tool always maintains a constant contact pressure with the two end faces of the tire blank, realizing bidirectional synchronous trimming in one clamping.

2. The trimming device in the tire forming process according to claim 1, characterized in that, The floating spindle is supported on the fixed frame by a sliding bearing. The axial length of the sliding bearing is less than the axial floating stroke of the floating spindle, so as to allow the floating spindle to float freely.

3. The trimming device in the tire forming process according to claim 2, characterized in that, The ball screw in the ball screw and nut assembly is coaxially fixed to the floating spindle, and the nut is rigidly connected to the corresponding tool holder, so that the axial displacement of the floating spindle directly drives the tool holder to move radially along the arc-shaped guide groove.

4. The trimming device in the tire forming process according to claim 3, characterized in that, The curvature center of the arc-shaped guide groove coincides with the rotation axis of the tire blank, so as to ensure that the cutting trajectory of the trimming tool matches the end face contour of the tire blank.

5. A trimming device for tire forming process according to claim 4, characterized in that, The roller is mounted on the bottom of the tool holder via an eccentric shaft. The gap between the roller and the arc-shaped guide groove can be finely adjusted by rotating the eccentric shaft.

6. A trimming device for tire forming process according to claim 5, characterized in that, The tool holder is L-shaped, with its vertical section fixedly connected to the nut of the ball screw nut assembly, the trimming tool installed at the end of the horizontal section, and the roller located below the horizontal section.

7. A trimming device for tire forming process according to claim 6, characterized in that, The trimming tool is detachably connected to the tool holder via a dovetail groove, so that the cutting edge of the tool is perpendicular to the end face of the blank.

8. A trimming device for tire forming process according to claim 7, characterized in that, The fixed frame is also equipped with a dust cover, which covers the ball screw nut pair and the arc-shaped guide groove to prevent rubber debris from entering the moving pair.

9. A trimming device for tire forming process according to claim 8, characterized in that, The floating spindle is provided with elastic buffers at both ends. One end of the elastic buffer abuts against the fixed frame, and the other end abuts against the end of the floating spindle, for absorbing axial impact.

10. A trimming device for tire forming process according to claim 9, characterized in that, The cross-section of the arc-shaped guide groove is "V" shaped, and the outer circumferential surface of the roller is provided with a tapered profile that matches the "V" shaped groove to prevent the roller from moving laterally during operation.

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