Anti-slip chuck of numerical control machine tool and application of anti-slip chuck

Abstract

The invention relates to the technical field of numerical control machine tool clamps, in particular to an anti-slip chuck of a numerical control machine tool and application of the anti-slip chuck. A power mechanism for driving the multiple clamping jaws to synchronously move in the radial direction of the chuck body is arranged in the chuck body. The power mechanism provides axial tension through a hydraulic cylinder; the power mechanism comprises a plurality of inclined strip discs correspondingly installed at the inner ends of the clamping jaws, a traction disc connected with the inclined strip discs in a sliding mode and a pull rod coaxially connected with the traction disc in a rotating mode. Optimization of a power transmission path is completed through an overall compact rear-pull type transmission layout, a cumbersome plane thread disc and a bevel gear set of a traditional horizontal pushing chuck are omitted, power is directly transmitted to an inclined strip disc and a clamping jaw through a pull rod via a traction disc and a cable-stayed sleeve, the path is simple, the number of parts is small, the mass distribution of a whole rotating body is more symmetrical, and the transmission efficiency is improved. And precise dynamic balance at a high speed can be realized more easily.

Description

Technical Field

[0001] This invention relates to the field of CNC machine tool fixture technology, specifically to an anti-slip chuck for CNC machine tools and its application. Background Technology

[0002] In the field of CNC machine tool machining, the chuck, as a core workpiece clamping device, directly determines the machining accuracy, efficiency, and safety. While traditional three-jaw flat-push chucks are widely used, their inherent defects in high-speed machining scenarios are becoming increasingly apparent: First, their transmission chain is lengthy, consisting of small bevel gears, large bevel gears, a flat threaded disc, and jaws, resulting in numerous parts and poor connection rigidity, making them prone to becoming weak points in the system under heavy-load cutting. Second, the independent flat threaded discs are large and eccentrically distributed, generating enormous centrifugal force during high-speed rotation. This not only disrupts the dynamic balance but also forces the jaws to open outwards, leading to severe attenuation or even failure of the clamping force, posing a significant safety hazard. Patent application CN202322872865.4 discloses a CNC machine tool chuck that is easy to replace, using a drive assembly to quickly complete the disassembly and assembly process of the chuck housing on the rotating shaft; however, it does not solve the problem of the jaw clamping motion mode on the chuck, and the clamping force is still affected by the centrifugal force of the chuck's rotation. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention aims to provide an anti-slip chuck for CNC machine tools and its application. To solve the problem of high-speed clamping force attenuation, a slanted rear pull chuck method has been developed. It directly pulls the inclined bar disc with a slant surface through the pull rod, driving the chuck to move radially. The transmission chain is short and the rigidity is high, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, on the one hand, the present invention provides an anti-slip chuck for a CNC machine tool, comprising a chuck body and a plurality of jaws evenly distributed circumferentially on the outer end face of the chuck body; the chuck body is provided with a power mechanism that drives the plurality of jaws to move synchronously along the radial direction of the chuck body; the power mechanism provides axial tension through a hydraulic cylinder; The power mechanism includes a plurality of inclined plates correspondingly installed at the inner ends of a plurality of jaws, a traction plate slidably connected to the plurality of inclined plates, and a pull rod rotatably connected to the traction plate on the same axis; in a cross-sectional plane passing through the axis of the chuck body, an acute angle θ is formed between the inclined surface of the inclined plate and the reference plane of the axis; the traction plate is located in the inner cavity of the chuck body and is coaxially arranged. The acute angle θ is configured such that when the chuck body rotates at high speed, the centrifugal force acting on the jaws is decomposed through the inclined plate mechanism, generating an additional centripetal force in the same direction as the pull rod's rear pulling force, which is used to dynamically enhance the radial clamping force of the jaws.

[0005] As a further improvement to this technical solution, the traction disc has a conical disc structure and several oblique pull sleeves are distributed in a ring at equal intervals along its edge. The oblique pull sleeves slide in conjunction with the oblique bar disc. The horizontal distance between the upper and lower ends of the oblique bar disc is equal to two-thirds of the length of the claw.

[0006] As a further improvement to this technical solution, a reinforcing sleeve is adapted to be provided on the outside of the inclined bar disc, and the reinforcing sleeve is adapted to be provided in the inner cavity of the inclined bar sleeve.

[0007] As a further improvement to this technical solution, the center hole of the traction disc is coaxially connected to a traction tube via a bearing, and the rear end of the traction tube is coaxially and fixedly connected to the front end of the traction rod.

[0008] As a further improvement to this technical solution, a connecting block is fixedly provided at the front end of the inclined bar disc, and the connecting block is fixedly connected to the inner end of the claw by bolts.

[0009] As a further improvement to this technical solution, the front end face of the chuck has two countersunk holes at the middle. When the chuck clamping end is turned, the countersunk hole closest to the central axis of the chuck body is selected to insert a bolt and fix it to the connecting block.

[0010] As a further improvement to this technical solution, the acute angle θ ranges from 10° to 30°.

[0011] As a further improvement to this technical solution, a torsion assembly is coaxially fixedly connected to the rear end of the chuck body. The torsion assembly is tubular and its inner diameter is larger than the outer diameter of the pull rod. A pulley is sleeved on the outer rear end of the assembly and is connected to the main spindle motor via a belt.

[0012] As a further improvement to this technical solution, the front end face of the chuck body is provided with a number of guide grooves in an annular radial pattern at equal intervals. The inner ends of the chuck claws are provided with symmetrical slide rails on both sides. A pair of slide rails are adapted to and engaged with the guide grooves for sliding. The inner end face of the guide groove is provided with a clearance groove. The inclined bar is engaged with the clearance groove.

[0013] On the other hand, the present invention provides an application of an anti-slip chuck for CNC machine tools, which is the aforementioned anti-slip chuck for CNC machine tools, applied in CNC machine tool fixtures.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The anti-slip chuck of this CNC machine tool and its application optimize the power transmission path through a compact "rear pull" transmission layout. It eliminates the bulky flat threaded disc and bevel gear set of the traditional flat push chuck. The power is directly transmitted from the pull rod through the pull plate and the inclined sleeve to the inclined bar disc and the jaws. The path is simple and the number of parts is small, which makes the mass distribution of the entire rotating body more symmetrical and makes it easier to achieve precision dynamic balance at high speed.

[0015] 2. The anti-slip chuck of this CNC machine tool and its application: By optimizing the design of the inclined plate angle θ in the range of 10°-30°, the centrifugal force is quantitatively converted. This design allows the centrifugal force acting on the jaws to be decomposed into an additional axial force in the same direction as the original tension according to a specific ratio. This force is converted into an additional radial clamping force through the inclined plate mechanism, thereby effectively compensating for the clamping force loss caused by centrifugal force. Actual measurements show that the high-speed clamping force attenuation can be controlled within 5% at the optimized angle, fundamentally solving the technical problem of high-speed clamping loss of traditional flat push chucks.

[0016] 3. The anti-slip chuck of this CNC machine tool and its application: By connecting the jaws and the inclined bar with adjustable bolts and opening multiple countersunk holes on the jaws to achieve flexible switching of clamping points, the technical effect of greatly expanding the clamping diameter range of the chuck is achieved without destroying the pull-back transmission chain and the "centrifugal force compensation" mechanism. Attached Figure Description

[0017] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, will select various possible shapes and proportions to implement the invention according to specific circumstances.

[0018] Figure 1 This is a schematic diagram of the overall assembly structure of the present invention; Figure 2 For the present invention Figure 1 Side view; Figure 3 This is one of the exploded views of the chuck body of the present invention; Figure 4 This is a second split view of the chuck body of the present invention; Figure 5 This is a schematic diagram of the assembly structure of the power mechanism of the present invention; Figure 6 For the present invention Figure 5 Side view; Figure 7 This is a schematic diagram of the traction disc assembly structure of the present invention; Figure 8 This is an assembly disassembly diagram of the inclined bar disc and the chuck of the present invention; The meanings of the labels in the diagram are as follows: 100. Chuck body; 101. Guide groove; 102. Clearance groove; 110. Chuck claw; 111. Slide rail; 120. Torsion assembly; 121. Connecting disc; 130. Pulley; 200. Power mechanism; 210. Inclined bar disc; 211. Connecting block; 220. Pulling disc; 221. Inclined pull sleeve; 230. Pull rod; 231. Pull pipe; 240. Reinforcing sleeve. Detailed Implementation

[0019] The details of the present invention can be more clearly understood by referring to the accompanying drawings and the description of specific embodiments. However, the specific embodiments of the present invention described herein are for illustrative purposes only and should not be construed as limiting the invention in any way. Under the teachings of this invention, those skilled in the art will conceive of any possible variations of the invention, all of which should be considered within the scope of the invention. The terms "installation" and "connection" should be interpreted broadly, referring to direct connection as well as indirect connection through an intermediate medium.

[0020] The terms "central axis," "vertical," "horizontal," "front," "rear," "upper," "lower," "left," "right," "top," "bottom," "inner," and "outer" used herein to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and are not intended to 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 the invention. Furthermore, in the description of the invention, "a number" means two or more, unless otherwise explicitly specified.

[0021] Please see Figures 1-4 As shown, the present invention provides an anti-slip chuck for CNC machine tools, which is used in CNC machine tool fixtures; it includes a chuck body 100 and a plurality of jaws 110 uniformly distributed circumferentially on the outer end face of the chuck body 100; a power mechanism 200 is provided inside the chuck body 100 to drive the plurality of jaws 110 to move synchronously along the radial direction of the chuck body 100; the power mechanism 200 provides axial tension through a hydraulic cylinder; a torsion assembly 120 is coaxially fixedly connected to the rear end of the chuck body 100, and a connecting plate 121 is coaxially welded to the outer wall of the front end of the torsion assembly 120, and the connecting plate 121 is fixedly connected to the rear end face of the chuck body 100 by bolts; a pulley 130 is sleeved on the outer rear end of the torsion assembly 120 and is connected to the spindle motor through a belt, so that the chuck body 100 obtains torsional force and the workpiece is clamped and rotated by the plurality of jaws 110.

[0022] The front end face of the chuck body 100 is provided with a number of guide grooves 101 that are equally spaced in a circular radial direction. The guide grooves 101 are cavities that are wider inside and narrower outside, thus forming a limiting structure. The inner ends of the jaws 110 are provided with symmetrical slide rails 111. A pair of slide rails 111 are adapted to engage and slide with the guide grooves 101, so that the jaws 110 slide radially along the chuck body 100 to adjust the clamping range so as to clamp workpieces of different diameters.

[0023] Specifically, such as Figures 5-8 As shown, the power mechanism 200 includes a plurality of inclined discs 210 correspondingly installed on the inner ends of a plurality of claws 110, a traction disc 220 slidably connected to the plurality of inclined discs 210, and a pull rod 230 rotatably connected to the traction disc 220 on the same axis; the inner end face of the guide groove 101 is provided with a relief groove 102, and the inclined discs 210 are slidably engaged with the relief groove 102.

[0024] In a cross-sectional plane passing through the axis of the chuck body 100, an acute angle θ is formed between the inclined surface of the slant bar 210 and the reference plane of the axis; the pull plate 220 is located in the inner cavity of the chuck body 100 and is coaxially arranged; the acute angle θ ranges from 10° to 30° and is configured such that when the chuck body 100 rotates at high speed, the centrifugal force acting on the jaw 110 is decomposed through the inclined surface mechanism of the slant bar 210, generating an additional centripetal force in the same direction as the pull force of the pull rod 230, which is used to dynamically enhance the radial clamping force of the jaw 110.

[0025] The power mechanism 200 adopts a "centrifugal force compensation" design. When the chuck 110 is thrown outward due to centrifugal force, it will be converted into additional centripetal force through the inclined surface of the inclined bar disc 210 to offset the loss of clamping force. The clamping force remains unchanged under high-speed rotation.

[0026] When the chuck rotates at high speed, the centrifugal force F generated by the jaw assembly 离 It is radially outward.

[0027] ①The centrifugal force F 离 Decompose along the inclined plane of the 210-degree angled bar: Normal force F perpendicular to the inclined plane 压 :F 压 =F 离 ×cosθ; This force generates contact pressure but does not directly produce a compensation effect. Tangential force F parallel to the inclined plane 切 :F 切 =F 离 ×sinθ; This force is along the direction of the inclined plane; ② F 切 Decomposed along the axial and radial directions: F 切 Axial component of force F 附 (Compensating force), F 附 =F 切 ×sinθ=F 离 ×sin²θ; F 切 radial component F 径回 F 径回 =F 切 ×cosθ=F 离 ×sinθ×cosθ; ③ Initial clamping force F 夹 (At low speed), the hydraulic pulling force F 拉 The radial clamping force generated by the inclined plane mechanism: Fclamping = Fclipping 拉 / tanθ; Compensation effect during high-speed rotation: harmful centrifugal force F 离 This causes the claws to open outwards; Beneficial axial compensation force F 附 =F 离 ×sin²θ; This force is related to F 拉 With the same direction, the total axial tensile force is enhanced; ④ Net compensation effect: The total axial tensile force becomes F 总轴 =F 拉 +F 附 ; The corresponding total radial clamping force: F 总夹 =(F 拉 +F 附 ) / tanθ; Net clamping force after compensation: F 净夹 =F 总夹 -F 离 =(F 拉 +F 离 ×sin²θ) / tanθ-F 离 ; ⑤ The compensation efficiency η = 1 / 2·sin2θ. This function reaches its maximum value of 0.5 when θ = 45°, but in practice, more factors need to be considered. a. Transmission efficiency / Clamping force amplification factor Original clamping force F 夹 =F 拉 / tanθ; The smaller θ is, the smaller tanθ is, and the greater the amplification factor of the clamping force; θ=15°:tan15°=0.268, magnification 3.73; θ = 25°: tan25° = 0.466, magnification 2.15; b. Structural feasibility If θ is too small (<10°): there is a high risk of self-locking, and extremely high manufacturing precision is required; If θ is too large (>30°): the compensation effect is good, but the clamping force amplification factor is low; Depending on the application scenario:

[0028] In summary, the advantages of choosing θ=18° are: The clamping force amplification factor is 3.08 times (tan18°=0.325), the compensation efficiency is 29.4%, and the measured attenuation at 8500rpm is <5%.

[0029] Furthermore, the pull plate 220 has a conical disc structure and several inclined pull sleeves 221 are distributed in a ring at equal intervals along its edge. The inclined pull sleeves 221 are engaged and slide with the inclined bar disc 210. The horizontal distance between the upper and lower ends of the inclined bar disc 210 is equal to two-thirds of the length of the jaw 110, so that the inclined pull sleeves 221 move along the axial direction of the chuck body 100, thereby driving the inclined bar disc 210 to have a stroke equal to this distance, so that the jaw 110 moves radially to form a range for clamping workpieces of various specifications.

[0030] The inclined bar disc 210 is fitted with a reinforcing sleeve 240 on its exterior. The reinforcing sleeve 240 is fitted into the inner cavity of the inclined pull sleeve 221. The thickness of the inclined bar disc 210 is 5-8mm. With the protection of the reinforcing sleeve 240, the inclined bar disc 210 is resistant to pressure and bending, and can stably drive the chuck 110 to maintain clamping force when rotating at high speed.

[0031] Furthermore, the center hole of the traction plate 220 is coaxially connected to the pull tube 231 via a bearing. The inner hole of the pull tube 231 is equal to the center hole of the chuck body 100, allowing the long shaft workpiece to be placed inside the pull tube 231 and clamped and installed by the jaws 110. The rear end of the pull tube 231 is coaxially and fixedly connected to the front end of the pull rod 230, so that the traction plate 220 rotates with the jaws 110 and simultaneously obtains the axial tension of the pull rod 230. The torsion kit 120 is tubular and its inner diameter is larger than the outer diameter of the pull rod 230, so that the pull rod 230 is pulled and extended by the hydraulic cylinder without interfering with the rotational movement of the pull tube 231.

[0032] Furthermore, a connecting block 211 is fixedly provided at the front end of the inclined bar disc 210, and the connecting block 211 is fixedly connected to the inner end of the jaw 110 by bolts; two countersunk holes are opened at the middle of the front end face of the jaw 110. In the prior art, the two sides of the jaw 110 can clamp workpieces of different ranges. When the clamping end of the jaw 110 is turned, the countersunk hole near the central axis of the chuck body 100 is selected to insert bolts and fix them to the connecting block 211, so that the different clamping ranges of the jaw 110 can be used for the "centrifugal force compensation" mechanism by the inclined pull of the power mechanism 200.

[0033] It should be noted that the fixed connection and fixing method of the present invention are achieved by conventional fixing means such as bolt connection, welding, or bonding that are compatible with each other. These are existing technologies and will not be described in detail here. The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A slip-proof chuck of a numerical control machine tool, comprising a chuck body and a plurality of jaws embedded in a circumferential direction on an outer end surface of the chuck body; characterized in that: The interior of the chuck body is provided with a power mechanism for driving the chuck claws to move synchronously along the radial direction of the chuck body; the power mechanism provides axial tension through a hydraulic cylinder; The power mechanism comprises a plurality of inclined strip plates corresponding to the inner ends of the chuck claws, a pulling plate in sliding connection with the inclined strip plates, and a pull rod in coaxial rotary connection with the pulling plate; in a cross-sectional plane passing through the axis of the chuck body, an acute angle θ is formed between the inclined surface of the inclined strip plate and the reference surface of the axis; the pulling plate is coaxially arranged in the inner cavity of the chuck body; The acute angle θ is configured such that when the chuck body rotates at high speed, the centrifugal force acting on the chuck claws is decomposed by the inclined surface mechanism of the inclined strip plate to generate an additional centripetal force in the same direction as the rear pulling force of the pull rod, thereby dynamically enhancing the radial clamping force of the chuck claws.

2. The anti-slip chuck for a numerically controlled machine tool according to claim 1, characterized in that: The pulling plate is in the form of a conical disc and has a plurality of inclined pull sleeves arranged at equal intervals in a ring shape at the edge thereof; the inclined pull sleeves are in sleeve sliding connection with the inclined strip plates; the horizontal distance between the upper and lower ends of the inclined strip plate is equal to two-thirds of the length of the chuck claw.

3. The anti-slip chuck for a numerically controlled machine tool according to claim 2, characterized in that: The outer fitting sleeve of the inclined strip plate is provided with a reinforcing sleeve which is fitted into the inner cavity of the inclined pull sleeve.

4. The anti-slip chuck for a numerically controlled machine tool according to claim 3, characterized in that: The central hole of the pulling plate is coaxially connected with a pull tube through a bearing; the rear end of the pull tube is fixedly connected with the front end of the pull rod in a coaxial manner.

5. The anti-slip chuck for a numerically controlled machine tool according to claim 4, characterized in that: The front end of the inclined strip plate is fixedly provided with a connecting block; the connecting block is fixedly connected with the inner end of the chuck claw through a bolt.

6. The anti-slip chuck for a numerically controlled machine tool according to claim 5, characterized in that: The front end surface of the chuck claw is provided with two counterbores at the middle portion; when the clamping end of the chuck claw is adjusted, the counterbores close to the central axis of the chuck body are selected to be fixedly connected with the connecting block through bolts.

7. The anti-slip chuck for a numerically controlled machine tool according to claim 6, characterized in that: The range of the acute angle θ is 10° to 30°.

8. The anti-slip chuck for a numerically controlled machine tool according to claim 7, characterized in that: The rear end of the chuck body is coaxially fixedly connected with a torsion sleeve; the torsion sleeve is in the form of a tube and has an inner diameter greater than the outer diameter of the pull rod; the rear end of the torsion sleeve is externally provided with a belt wheel which is drivingly connected with the main shaft motor through a belt.

9. The anti-slip chuck for a numerically controlled machine tool according to claim 8, characterized in that: The front end surface of the chuck body is provided with a plurality of guide sliding grooves arranged at equal intervals in a ring shape in the radial direction; the inner end of the chuck claw is symmetrically provided with sliding rails; a pair of the sliding rails are in fitting sliding connection with the guide sliding grooves; the inner end surface of the guide sliding groove is provided with a clearance groove; the inclined strip plate is in sliding fitting connection with the clearance groove.

10. A slip-proof chuck application for a numerically controlled machine tool according to claim 9, characterized in that: The application is used in a numerical control machine tool clamp.

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