Anti-loose chuck jaw positioning and matching structure

Abstract

The application discloses a chuck jaw positioning and matching structure capable of preventing loosening, which comprises a chuck body, a sliding seat and a jaw. At least one protruding guide positioning key is arranged at the connecting end of the sliding seat towards the jaw. The bottom of the jaw is provided with a key groove matched with the guide positioning key. A curved surface locking part is arranged on at least one inclined surface of the guide positioning key along the length direction. A locking assembly capable of elastically engaging with the curved surface locking part is arranged on the corresponding inclined surface of the jaw key groove. When the jaw is installed on the sliding seat, the locking assembly is elastically engaged with the curved surface locking part under the action of axial compression force, thereby forming an over-positioning locking state capable of preventing the jaw from slightly moving and loosening. The main positioning is realized through the matching of the key groove and the inclined surface of the positioning key, and the continuous anti-micro-motion and anti-loosening capability is provided through the elastically engaged curved surface locking structure, so that the clamping precision and reliability of the chuck under the high-speed and high-load working condition are remarkably improved, and the maintenance is still convenient.

Description

Technical Field

[0001] This invention relates to the field of machine tool accessories technology, and in particular to a chuck jaw positioning and mating structure to prevent loosening. Background Technology

[0002] Pneumatic chucks, widely used in modern CNC machine tools, function primarily to quickly and accurately clamp workpieces by driving replaceable jaws through multiple radially sliding slides along the chuck body. Examples include the K11800A-K111250A large mechanical chucks. The jaws and slides typically use T-slots, toothed slots, or other mating structures and are secured with screws. However, under high-speed rotation, intermittent cutting, or impact vibration conditions, the mating surfaces between the jaws and slides are prone to slight relative slippage due to alternating loads and vibrations. Over time, this can lead to a decrease in the preload of the fastening screws, an increase in the clearance, and even jaw loosening. This slight loosening not only reduces the workpiece's repeatability and affects machining quality but also poses safety hazards.

[0003] In existing technologies, this problem is usually alleviated by improving machining accuracy, increasing preload, or using anti-loosening threaded components, but the effects are limited and may lead to problems such as inconvenient assembly and disassembly, and easy wear. Therefore, there is a need for a chuck positioning and mating structure that can both ensure quick assembly and disassembly of the chucks and fundamentally and effectively suppress micro-movement and loosening. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a chuck jaw positioning and mating structure that prevents loosening. This structure, while realizing the traditional guiding and positioning function, introduces an active elastic anti-loosening mechanism, which can effectively resist micro-movement and maintain long-term stable clamping accuracy.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A chuck jaw positioning and mating structure for preventing loosening is applied to a pneumatic chuck including a chuck body, a plurality of slides that slide radially along the chuck body, and jaws that are detachably connected to the slides. The slides are provided with at least one protruding guide positioning key at the connecting end facing the jaws, and the bottom of the jaws is provided with a keyway that mates with the guide positioning key. At least one inclined surface of the guide positioning key is provided with a curved locking part along its length direction; On the corresponding inclined surface of the keyway of the claw, a locking component is provided that can elastically engage with the curved locking part; When the pawl is installed on the slide, the locking assembly elastically engages with the curved locking part under the action of axial clamping force, forming an over-positioning locking state to prevent the pawl from loosening due to slight movement.

[0006] Furthermore, the guide locating key has a trapezoidal cross-section; correspondingly, the keyway has a matching trapezoidal cross-section. This wedge fit provides good radial positioning and anti-overturning capability.

[0007] Furthermore, the curved locking part is an intermittent arc-shaped groove formed on the inclined surface of the guide positioning key. The intermittent design helps to disperse stress and facilitates processing.

[0008] Furthermore, the locking component is an arc-shaped locking piece embedded in the inclined surface of the keyway of the claw, and the radius of curvature of the arc-shaped locking piece is smaller than the radius of curvature of the arc-shaped groove. This dimensional difference ensures that the locking piece and the groove form line contact or small-area contact, generating elastic deformation and continuous contact pressure during clamping.

[0009] Furthermore, one or more arc-shaped locking pieces are arranged parallel to the length of the keyway slope, and the outer surface of the arc-shaped locking piece is coated with a rubber coating. The multi-piece design can provide a more balanced locking force; the rubber coating can increase damping, absorb high-frequency micro-vibrations, and prevent metal-to-metal seizing.

[0010] Furthermore, each guide locating key has a curved locking portion on both inclined surfaces. This achieves bidirectional anti-loosening, effectively suppressing micro-movement regardless of the radial force applied to the chuck.

[0011] Furthermore, after the jaws are installed, there is a gap between the top plane of the guide positioning key and the top plane of the keyway. This gap ensures that the positioning reference for the mating primarily falls on the inclined surface, avoiding positioning instability caused by poor contact of the top plane.

[0012] Furthermore, between the sliding contact end face and the bottom surface of the chuck, outside the area of ​​the guide positioning key and keyway, one or more carbide anti-wear bumps are provided. These anti-wear bumps serve as auxiliary support points, bearing most of the end face friction and wear, protecting the main positioning structure, and extending its service life.

[0013] Furthermore, the groove surface of the curved locking part and the meshing surface of the locking assembly are both treated with PVD coating. PVD coating has high hardness, low coefficient of friction and good wear resistance, which can significantly improve the durability of the anti-loosening assembly.

[0014] Furthermore, the claw is mounted on the slide block using fasteners, specifically screws. This is the most common and reliable connection method. Beneficial effects

[0015] Compared with the prior art, the present invention has the following significant advantages: 1. Through the elastic engagement of the locking component and the curved locking part, a continuous normal pressure that resists fretting is formed between the mating inclined surfaces. This transforms the traditional rigid fit + screw locking passive anti-loosening mode into a rigid positioning + elastic locking active anti-loosening mode, fundamentally suppressing the generation of fretting slippage.

[0016] 2. It eliminates the problem of increased clearance caused by micro-motion, ensuring the long-term repeatability of the chuck's positioning accuracy on the slide, thereby guaranteeing the machining accuracy of the workpiece.

[0017] 3. The anti-wear protrusions transfer end-face wear, and the PVD coating improves the wear resistance of key contact surfaces. The overall structure can maintain reliable performance under harsh working conditions and has a long service life.

[0018] 4. This anti-loosening structure is integrated into the existing keyway positioning system without changing the external installation dimensions and interfaces of the chuck body and jaws. This facilitates the upgrading and modification of existing chucks and also facilitates the standardized production and quick replacement of jaws.

[0019] 5. The locking component is a replaceable part. When wear occurs, only this small part needs to be replaced to restore the anti-loosening performance. There is no need to replace the entire jaw or slide, resulting in low maintenance costs. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a chuck jaw positioning and mating structure for preventing loosening, as described in an embodiment of this application. Figure 2 This is a schematic diagram of a chuck jaw positioning and mating structure for an anti-loosening chuck jaw in an embodiment of this application; Figure 3 This application provides an embodiment of a chuck jaw positioning and mating structure to prevent loosening. Figure 2 Partial cross-sectional structural diagram; Figure 4 This application provides an embodiment of a chuck jaw positioning and mating structure to prevent loosening. Figure 3 Enlarged structural diagram at point A; Figure 5 This is a schematic diagram of a slide block structure for an anti-loosening chuck claw positioning and mating structure in an embodiment of this application; Figure 6This is a schematic diagram of the sliding block and jaw engagement structure of an anti-loosening chuck jaw positioning and engagement structure in an embodiment of this application.

[0022] In the diagram: 1. Chuck body; 2. Slide; 21. Connecting end face; 22. Guide positioning key; 221. Bevel; 222. Arc groove; 223. Top plane; 3. Claw; 31. Bottom surface; 32. Keyway; 321. Bevel; 33. Locking assembly; 4. Carbide anti-wear protrusions; 5. Fastener mounting hole; 6. Clearance; 7. Fastener. Detailed Implementation

[0023] 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 embodiments of the present invention, and not all embodiments. 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.

[0024] In the description of this disclosure, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] It should also be noted that all standard parts used in this application are commercially available, and can be custom-made according to the description and drawings. Unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure based on the specific circumstances, and unless explicitly limited, machinery, parts, and equipment can all adopt conventional models in the prior art.

[0026] In this document, the term "comprising" is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0027] Example: Reference Figure 1-6 The diagram shows a chuck jaw positioning and mating structure to prevent loosening. This structure is applied to conventional pneumatic chucks. The chuck includes a chuck body 1, multiple slides 2 that can slide radially along the chuck body, and jaws 3 connected to the slides 2 through this structure.

[0028] The top of the slide 2 is machined with a protruding guide positioning key 22. The cross-section of the guide positioning key 22 is an isosceles trapezoid. On the two inclined surfaces 221 of the guide positioning key 22, multiple spaced arc-shaped grooves are machined along its length, and these arc-shaped grooves together constitute the curved surface locking part 222. On the connecting end face 21 of the slide 2, in the area between the two guide positioning keys 22, multiple wear-resistant bumps 4 made of hard alloy are embedded.

[0029] The bottom of the chuck 3 is machined with two trapezoidal keyways 32 that precisely mate with the two guide positioning keys 22. On the two inclined surfaces 321 of each keyway 32, corresponding to the positions of the curved locking parts 222 on the slide block 2, two parallel arc-shaped locking pieces 33 are embedded as locking components. The radius of curvature of the raised surface of the arc-shaped locking piece 33 is slightly smaller than the radius of curvature of the arc-shaped groove 222 on the guide positioning key 22. The outer surface of the arc-shaped locking piece 33 is covered with a thin rubber coating 331. The chuck 3 is secured to the slide block 2 by multiple screws 7 passing through its body and screwed into the threaded holes of the slide block 2.

[0030] During installation, align the keyway 32 of the chuck 3 with the guide positioning key 22 of the slide 2 and insert it, then tighten the fastening screw 7. Under the axial clamping force provided by the screw 7, the chuck 3 is pulled towards the slide 2. Since the guide positioning key 22 engages with the trapezoidal inclined surface of the keyway 32, the axial clamping force is decomposed into a normal force perpendicular to the inclined surface. Under the action of this normal force, the arc-shaped locking piece 33 on the inclined surface 321 of the chuck keyway is pressed into the arc-shaped groove 222 on the inclined surface 221 of the guide positioning key. Due to the small radius of curvature of the locking piece 33, it undergoes slight elastic deformation, thereby forming a tight, pre-loaded line contact engagement with the groove 222.

[0031] During chuck operation, if a force causes radial fretting in the jaws 3, the relative sliding tendency between the inclined surfaces will attempt to push the locking plate 33 out of the groove 222. However, since the locking plate 33 is in an elastically compressed state, overcoming this engagement requires additional energy, thus effectively damping and suppressing fretting. The rubber coating 331 further enhances the damping and vibration absorption effect.

[0032] In another optimized embodiment, a small gap 6 is maintained between the top plane 223 of the guide positioning key 22 and the top plane of the keyway 32 after final installation and tightening. This ensures that all positioning and locking forces are transmitted through the bevel, avoiding the problem of poor contact caused by machining errors of the top plane, which in turn affects the stability of positioning.

[0033] In addition, the surfaces of all arc-shaped grooves 222 and the meshing surfaces of arc-shaped locking pieces 33 are treated with PVD coating to significantly improve their surface hardness and wear resistance, ensuring the longevity of their anti-loosening performance.

[0034] In summary, this invention, through the elastic engagement of the locking component and the curved locking part, forms a continuous, fretting-resistant normal pressure between the mating inclined surfaces. This transforms the traditional rigid fit + screw locking passive anti-loosening mode into a rigid positioning + elastic locking active anti-loosening mode, fundamentally suppressing fretting slippage and eliminating the problem of increased mating clearance caused by fretting. This ensures the long-term repeatability of the chuck's positioning accuracy on the slide, thereby guaranteeing the workpiece's machining accuracy. The anti-wear protrusions transfer end-face wear, and the PVD coating improves the wear resistance of key contact surfaces. The overall structure maintains reliable performance under harsh working conditions and has a long service life. This anti-loosening structure is integrated into the existing keyway positioning system without changing the external mounting dimensions and interfaces of the chuck body and chuck, facilitating upgrades and modifications to existing chucks and standardizing the production and quick replacement of chucks. The locking component is a replaceable part; when wear occurs, only this small part needs to be replaced to restore the anti-loosening performance, without replacing the entire chuck or slide, resulting in low maintenance costs.

[0035] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A chuck jaw positioning and mating structure for preventing loosening, applied in a pneumatic chuck comprising a chuck body, a plurality of slide blocks sliding radially along the chuck body, and jaws detachably connected to the slide blocks; characterized in that: The slide (2) has at least one protruding guide positioning key (22) at the connecting end facing the claw; the bottom of the claw (3) has a keyway (32) that cooperates with the guide positioning key (22). At least one inclined surface of the guide positioning key (22) is provided with a curved locking part (222) along its length direction. On the corresponding inclined surface of the keyway (32), a locking component (33) is provided that can elastically engage with the curved locking part (222). When the pawl (3) is installed on the slide (2), the locking assembly (33) forms an elastic engagement with the curved locking part (222) under the action of axial clamping force.

2. The anti-loosening chuck jaw positioning and mating structure according to claim 1, characterized in that: The cross-section of the guide positioning key (22) is trapezoidal, and the cross-section of the keyway (32) is a trapezoidal structure that matches it.

3. The anti-loosening chuck jaw positioning and mating structure according to claim 1, characterized in that: The curved locking part (222) is an intermittent arc-shaped groove opened on the inclined surface (221) of the guide positioning key (22).

4. The anti-loosening chuck jaw positioning and mating structure according to claim 1, characterized in that: The locking component (33) is an arc-shaped locking piece embedded in the inclined surface (321) of the keyway of the claw, and the radius of curvature of the arc-shaped locking piece is smaller than the radius of curvature of the arc-shaped groove (222).

5. The anti-loosening chuck jaw positioning and mating structure according to claim 4, characterized in that: One or more arc-shaped locking pieces (33) are arranged parallel to the length direction of the keyway slope (321), and the outer surface of the arc-shaped locking piece (33) is provided with a rubber coating (331).

6. The anti-loosening chuck jaw positioning and mating structure according to claim 2, characterized in that: Each guide positioning key (22) has a curved locking part (222) on both inclined surfaces (221).

7. The anti-loosening chuck jaw positioning and mating structure according to claim 6, characterized in that: There is a gap (6) between the top plane (223) of the guide positioning key (22) and the top plane of the keyway (32).

8. The anti-loosening chuck jaw positioning and mating structure according to claim 1, characterized in that: Between the sliding block connecting end face (21) and the claw bottom face (31), outside the area of ​​the guide positioning key (22) and keyway (32), there are multiple hard alloy anti-wear bumps (4).

9. The anti-loosening chuck jaw positioning and mating structure according to claim 3, characterized in that: The groove surface of the curved locking part (222) and the meshing surface of the locking assembly (33) are both treated with PVD coating.

10. The anti-loosening chuck jaw positioning and mating structure according to claim 1, characterized in that: The claw (3) is mounted on the slide (2) by a fastener (7), which is a screw.

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