Elastic chuck capable of being pre-positioned

Abstract

The utility model discloses a prepositionable elastic chuck, which comprises a locking sleeve, which is a cylinder with one open end, the closed end of the locking sleeve is provided with a locking sleeve through hole, a workpiece coaxially penetrates through the locking sleeve through hole, a pushing shaft with a cylinder is coaxially sleeved in the locking sleeve, and the inner wall, close to the locking sleeve through hole, of the pushing shaft gradually expands outwards to the outer end to form a pushing wedge surface; the positioning shaft plug is coaxially arranged in the pushing shaft in a sleeved mode, the open end of the positioning shaft plug faces the locking sleeve through hole, an inner cylinder of the positioning shaft plug is matched with the section of a workpiece, the petal-shaped chucks are arranged between the locking sleeve through hole and the pushing shaft in a circumferential mode, movable gaps exist between the petal-shaped chucks, and the petal-shaped chucks can bloom outwards or gather inwards. The inner wall of the petal-shaped chuck is attached to the workpiece in a matched mode, the outer wall of the petal-shaped chuck forms a chuck wedge face in the direction of the pushing shaft, and pre-positioning and high-precision clamping of the workpiece are achieved through the combined design of the locking sleeve, the pushing shaft, the positioning shaft plug and the petal-shaped chuck.

Description

Technical Field

[0001] This utility model relates to the field of machining fixture technology, specifically to a pre-positionable elastic chuck. Background Technology

[0002] In the field of machining, spring collets are common workpiece clamping devices, and their positioning accuracy directly affects the geometry and positional accuracy of the machined parts. Traditional spring collets typically employ a multi-lobed jaw structure, using a locking sleeve to apply axial force to retract the collet and clamp the workpiece. However, such collets have several problems in practical applications: First, the initial coaxiality between the collet and the machine tool spindle is difficult to reliably guarantee. Due to the lack of an effective pre-positioning mechanism between the collet and the spindle, during the locking process, the different lobes of the collet may shift due to uneven force or structural gaps, preventing the workpiece axis from completely aligning with the spindle axis. This problem is particularly prominent when machining workpieces with spherical surfaces or complex contours, easily causing positional deviations between the machined surface and the reference surface.

[0003] Secondly, traditional chucks lack stability before and after locking. In the unlocked state, the workpiece is temporarily fixed only by the friction of the chuck's inner wall. If subjected to slight external force or vibration, the workpiece may shift. During locking, the axial thrust of the locking sleeve is transmitted to the workpiece through the chuck's wedge surface. However, due to the lack of rigid constraint between the chuck and the locking sleeve, the chuck's segments may exhibit radial deviation due to elastic deformation or clearance when closing, further exacerbating axial misalignment. This deviation not only affects clamping accuracy but may also lead to uneven stress distribution between the chuck and the workpiece, accelerating wear and reducing service life over long-term use.

[0004] Furthermore, existing chucks present inconveniences when disassembling workpieces. Even after the locking sleeve is released, residual friction may still exist between the chuck and the workpiece, requiring additional tools or hammering for separation. This is not only inefficient but may also damage the workpiece surface or the chuck structure. Although some chucks are designed with unloading aids, these typically increase the complexity of the device and have limited unloading effectiveness.

[0005] To address these issues, the industry has attempted to improve performance by increasing machining accuracy or optimizing chuck materials, but these methods are costly and have limited effectiveness. Another solution proposes adding auxiliary positioning rings to the outside of the chuck, but such designs often result in bulky structures that are difficult to adapt to confined machining spaces.

[0006] Therefore, there is an urgent need to propose a simple chuck structure to achieve rapid pre-positioning and high-precision stable clamping of the workpiece. Utility Model Content

[0007] This invention provides a pre-positionable elastic chuck with a simple structure, suitable for use in confined machining spaces, enabling rapid pre-positioning and high-precision, stable clamping of workpieces.

[0008] To achieve these objectives and other advantages of this utility model, a pre-positionable elastic chuck is provided, comprising: a locking sleeve, which is a cylindrical structure open at one end, with a locking sleeve through hole at the center of the closed end of the locking sleeve, and a workpiece coaxially passing through the locking sleeve through hole; a push shaft, which enters from the open end of the locking sleeve and is coaxially sleeved within the locking sleeve, the push shaft being a cylindrical body, and the push shaft gradually expands outward from the inner wall near the locking sleeve through hole to form a push wedge surface; and a positioning plug, which is a cylindrical body coaxially sleeved within the push shaft and open at one end, with its open end facing the locking sleeve through hole. The locking sleeve has a through hole, and the inner cylinder of the positioning shaft plug matches the cross section of the workpiece. A plurality of petal-shaped chucks are arranged circumferentially between the locking sleeve through hole and the push shaft. There is a movable gap between the petal-shaped chucks, which can open outward or close inward. The inner wall of the petal-shaped chucks matches and contacts the workpiece, and the outer wall of the petal-shaped chucks gradually shrinks inward toward the push shaft to form a chuck wedge surface that matches the push wedge surface. Under the action of the axial force of the push shaft, the petal-shaped chucks abut against the area around the locking sleeve through hole. The plurality of petal-shaped chucks are closed inward by the action of the push wedge surface and clamp the workpiece together.

[0009] Preferably, the outer wall of the petal-shaped chuck extends out with a chuck retaining ring, and the locking sleeve has a plurality of screw holes, in which a stop screw is inserted. When the end of the petal-shaped chuck abuts against the locking sleeve, the stop screw extends into the end of the locking sleeve and blocks the chuck retaining ring, preventing the petal-shaped chuck from moving axially.

[0010] Preferably, the open end of the positioning shaft plug extends radially outward into an annular flange, and the inner wall of the push shaft has an annular groove with a width greater than the thickness of the annular flange, and the annular flange is located within the annular groove.

[0011] Preferably, the pushing wedge surface is an inner conical surface, and the clamping wedge surface is an outer conical surface.

[0012] Preferably, the edge of the push wedge surface located inside the push shaft extends inward with a blocking ring plate, and the end of the petal-shaped chuck facing the blocking ring plate forms a top-abutting end face, wherein when the chuck wedge surface contacts the push wedge surface, the top-abutting end face abuts against the blocking ring plate.

[0013] Preferably, the push shaft has a vent hole on the cylinder wall on the side away from the workpiece from the positioning shaft plug.

[0014] Preferably, the number of the petal-shaped clamps is 6.

[0015] This utility model has at least the following beneficial effects:

[0016] First, this utility model achieves pre-positioning and high-precision clamping of workpieces through the combined design of locking sleeve, push shaft, positioning shaft plug and petal-shaped chuck. The cylindrical structure of the positioning shaft plug matches the cross-section of the workpiece, ensuring that the workpiece is coaxial with the spindle before clamping. The push wedge surface of the push shaft and the chuck wedge surface of the petal-shaped chuck cooperate, so that the petal-shaped chuck is evenly gathered under the action of axial force, reducing or eliminating the gap between the petal-shaped chucks. This structure separates the positioning and locking actions, avoids the axial offset caused by the locking process of traditional chucks, and significantly improves the clamping accuracy of workpieces. It is especially suitable for the processing of high-precision spherical or complex contour workpieces.

[0017] Secondly, the cooperation between the collet retaining ring and the stop screw effectively restricts the axial movement of the petal-shaped collet. After the workpiece is locked, the stop screw extends into the end of the locking sleeve and blocks the collet retaining ring, preventing the petal-shaped collet from continuing to follow the push shaft back due to friction when the push shaft is pulled back, thus preventing the problem of the extrusion relationship between the collet, the workpiece, and the push shaft from being resolved.

[0018] Third, the push wedge surface and the chuck wedge surface adopt a matching design of inner and outer conical surfaces, which optimizes the force transmission path. The conical surface contact increases the contact area between the chuck and the push shaft, so that the axial thrust is more evenly converted into radial clamping force, avoiding chuck deformation caused by local stress concentration. In addition, the conical surface fit has self-centering characteristics, which can automatically compensate for slight assembly errors, further improving clamping accuracy and stability.

[0019] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall disassembly of the device in one technical solution of this utility model;

[0021] Figure 2 This is a side cross-sectional view of the device in one technical solution of this utility model;

[0022] Figure 3 This is a schematic diagram of the working process of one technical solution of this utility model. Figure 1 ;

[0023] Figure 4 This is a schematic diagram of the working process of one technical solution of this utility model. Figure 2 ;

[0024] Figure 5 This is a schematic diagram of the petal-shaped clamp in one technical solution of this utility model.

[0025] Figure descriptions: 1-Workpiece, 2-Locking sleeve, 21-Locking sleeve fixing surface, 210-Locking sleeve through hole, 22-Screw hole, 3-Petal-shaped chuck, 30-Chuck pushing surface, 31-Chuck retaining ring, 32-Chuck wedge surface, 33-Top end face, 4-Stop screw, 5-Positioning shaft plug, 51-Annular flange, 6-Pushing shaft, 60-Pushing shaft inner cavity, 61-Ventilation hole, 62-Annular groove, 63-Blocking ring, 64-Pushing wedge surface. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0027] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0028] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are conventional methods, and the components described are commercially available unless otherwise specified. In the description of this utility model, it should be noted that, unless otherwise explicitly stated and limited, the terms "installation," "connection," and "setting" should be interpreted broadly. For example, they can refer to fixed connection or setting, detachable connection or setting, or integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. The terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," 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 utility model and simplifying the description. They do not indicate or imply that the device or component 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 utility model.

[0029] like Figure 1-5As shown, the technical solution of this application provides a pre-positionable elastic chuck, comprising: a locking sleeve 2, which is a cylindrical structure open at one end, with a locking sleeve through hole 210 at the center of the closed end of the locking sleeve 2, and a workpiece 1 coaxially passing through the locking sleeve through hole 210; a push shaft 6, which enters from the open end of the locking sleeve 2 and is coaxially sleeved within the locking sleeve 2, the push shaft 6 being a cylindrical body, and the push shaft 6 gradually expands outward from the inner wall near the locking sleeve through hole 210 to form a push wedge surface 64; and a positioning plug 5, which is a cylindrical body coaxially sleeved within the push shaft 6 and open at one end, with its open end facing the locking sleeve through hole 210. The inner cylinder of the positioning shaft plug 5 matches the cross section of the workpiece 1; a plurality of petal-shaped chucks 3 are arranged circumferentially between the locking sleeve through hole 210 and the push shaft 6. There is a movable gap between the petal-shaped chucks 3, which can open outward or close inward. The inner wall of the petal-shaped chucks 3 matches and contacts the workpiece 1. The outer wall of the petal-shaped chucks 3 gradually shrinks inward toward the push shaft 6 to form a chuck wedge surface 32 that matches the push wedge surface 64. Under the action of the axial force of the push shaft 6, the petal-shaped chucks 3 abut against the area around the locking sleeve through hole 210. The plurality of petal-shaped chucks 3 are closed inward by the action of the push wedge surface 64 and together clamp the workpiece 1.

[0030] In this technical solution, such as Figure 2 , Figure 3 As shown, the locking sleeve 2 is fixed to an external machine tool or worktable. A locking sleeve fixing surface 21 is provided around the locking sleeve through hole 210 inside the locking sleeve 2. The end of the petal-shaped chuck 3 is provided with a chuck pushing surface 30 that matches the locking sleeve fixing surface 21. The section of the pushing shaft 6 away from the petal-shaped chuck 3 is connected to an external driving device such as a cylinder or hydraulic cylinder, allowing it to be pulled out and pushed in within the locking sleeve 2, and providing thrust to the petal-shaped chuck 3. The size of the locking sleeve through hole 210 is larger than the cross-section of the workpiece 1, allowing the workpiece 1 to be easily inserted into the locking sleeve through hole 210 from the outside. During the pre-positioning stage, the pushing shaft 6 does not push the petal-shaped chuck 3; the workpiece 1 is inserted from the locking sleeve through hole 210 to the positioning shaft plug. 5. Align the spindle axis with the inner core. At this time, the petal-shaped chuck 3 loosely surrounds the outer periphery of the workpiece 1. During the locking stage, the external drive device pushes the push shaft 6 to move towards the petal-shaped chuck 3. The push surface 30 of the chuck tightly abuts against the fixing surface 21 of the locking sleeve. During the advancement process, the push wedge surface 64 and the chuck wedge surface 32 of the petal-shaped chuck 3 are in complete contact, forcing the petal-shaped chuck 3 to converge towards the workpiece 1 and evenly clamp the workpiece 1. The workpiece 1 is radially fixed. During the disassembly stage, after the workpiece 1 is processed, the push shaft 6 moves in the opposite direction, the chuck wedge surface 32 and the push wedge surface 64 are released, the petal-shaped chuck 3 returns to its initial state, the radial constraint of the workpiece 1 is released, and it can be directly pulled out from the locking sleeve through hole 210.

[0031] This technical solution achieves pre-positioning and high-precision clamping of workpiece 1 through the combined design of locking sleeve 2, push shaft 6, positioning shaft plug 5 and petal-shaped chuck 3. The cylindrical structure of positioning shaft plug 5 matches the cross-section of workpiece 1, ensuring that workpiece 1 is coaxial with the main shaft of locking sleeve 2 before clamping. The push wedge surface 64 of push shaft 6 cooperates with the chuck wedge surface 32 of petal-shaped chuck 3, so that petal-shaped chuck 3 is evenly gathered under the axial force applied by push shaft 6, eliminating gaps. This structure separates the positioning and locking actions, avoiding the axial offset caused by the locking process of traditional chucks, and significantly improving the clamping accuracy of workpiece 1. It is especially suitable for the machining of high-precision spherical or complex contour workpieces.

[0032] In another technical solution, a chuck ring 31 extends from the outer wall of the petal-shaped chuck 3, and the locking sleeve 2 has several screw holes 22. A stop screw 4 passes through each screw hole 22. When the end of the petal-shaped chuck 3 abuts against the locking sleeve 2, the stop screw 4 extends into the end of the locking sleeve 2 and blocks the chuck ring 31, preventing the petal-shaped chuck 3 from moving axially. Figure 2 , Figure 3 As shown, multiple screw holes 22 are evenly opened circumferentially at the open end of the locking sleeve 2. A stop screw 4 is installed in each screw hole 22. A chuck retainer 31 is machined on the outer wall of the petal-shaped chuck 3. Its outer diameter is slightly smaller than the inner diameter of the locking sleeve 2. After the locking stage is completed, the stop screw 4 is screwed into the screw hole 22. When the push shaft 6 is pulled back during the reset stage, the chuck retainer 31 is blocked by the head of the stop screw 4. The petal-shaped chuck 3 is peeled off from the push shaft 6. This avoids the problem that the push wedge surface 64, the petal-shaped chuck 3, and the workpiece 1 cannot be released from mutual compression after being subjected to large force without any blocking measures, making it difficult to pull out the workpiece 1.

[0033] In another technical solution, the open end of the positioning shaft plug 5 extends radially outward through an annular flange 51. The inner wall of the push shaft 6 has an annular groove 62 with a width greater than the thickness of the annular flange 51. The annular flange 51 is located within the annular groove 62. In this technical solution, the positioning shaft plug 5, through the engagement of the annular flange 51 and the annular groove 62 on the inner wall of the push shaft 6, allows for a certain amount of axial floating displacement. During the pre-positioning stage, the dimensions of the workpiece 1 may have slight tolerances, or there may be alignment deviations during assembly. If the positioning shaft plug 5 is completely fixed, these slight dimensional differences can make it difficult to insert the workpiece 1. Forced assembly could cause scratches on the surface of the workpiece 1. 5. The axial floating design allows the workpiece to be smoothly inserted into the inner hole of the positioning shaft plug 5 without repeated adjustments, significantly shortening the clamping time. During the clamping stage, when the push shaft 6 moves towards the closed end of the locking sleeve 2, it pushes the annular flange 51 through the side wall of the annular groove 62, forcing the positioning shaft plug 5 and the workpiece 1 to move axially synchronously. The floating space of the positioning shaft plug 5 is eliminated, avoiding the offset caused by vibration during clamping. During the disassembly stage, when the push shaft 6 moves in the opposite direction, the floating property of the positioning shaft plug 5 can reduce the residual friction between the workpiece 1 and the petal-shaped chuck 3. When the petal-shaped chuck 3 is released, the workpiece 1 can slightly retract with the positioning shaft plug 5, further reducing the disassembly resistance and avoiding the disassembly difficulties caused by friction jamming of traditional chucks.

[0034] In another technical solution, the push wedge surface 64 is an inner conical surface, and the chuck wedge surface 32 is an outer conical surface. The conical matching design of the push wedge surface 64 and the chuck wedge surface 32 significantly improves the overall performance of the chuck through the precise fit between the inner and outer conical surfaces. The conical structure has a self-centering effect, which automatically guides the petal-shaped chuck 3 to converge towards the center under the axial thrust of the push shaft 6, corrects assembly deviations, and ensures the coaxiality accuracy of the workpiece 1 and the push shaft 6. The conical structure makes the axial force uniformly converted into radial clamping force, avoids local stress concentration, and is suitable for non-destructive clamping of thin-walled or high-precision workpieces.

[0035] In another technical solution, the pushing wedge surface 64 has a blocking ring plate 63 extending inward from the edge inside the pushing shaft 6. The end of the petal-shaped chuck 3 facing the blocking ring plate 63 has a top-abutting end face 33. When the chuck wedge surface 32 contacts the pushing wedge surface 64, the top-abutting end face 33 abuts against the blocking ring plate 63. In this technical solution, the blocking ring plate 63 is an annular protrusion on the inner wall of the pushing shaft 6, and the top-abutting end face 33 is located at the end of the petal-shaped chuck 3 near the pushing shaft 6. When the pushing shaft 6 is moved by axial thrust, the pushing wedge surface 64 pushes the chuck wedge surface 32, forcing the petal-shaped chuck 3 to converge inward. During this process, the top-abutting end face 33 finally abuts against the blocking ring plate 63 to form a rigid limit, preventing the petal-shaped chuck 3 from moving further. The final positions of several petal-shaped chucks 3 are consistent, resulting in a more uniform clamping effect on the workpiece 1.

[0036] In another technical solution, the push shaft 6 has a vent 61 on the cylinder wall on the side of the positioning shaft plug 5 away from the workpiece 1, such as... Figure 2 As shown, the push shaft 6 is a semi-enclosed cylinder. The positioning shaft plug 5 and the closed end of the push shaft 6 form the push shaft inner cavity 60. The push shaft inner cavity 60 balances the air pressure through the vent hole 61. When clamped, the air is exhausted, and when released, the air is introduced, thus eliminating the vacuum adsorption effect.

[0037] In another technical solution, the number of the petal-shaped clamps 3 is 6. The 6 evenly distributed petal-shaped clamps 3 form a six-point positioning, symmetrically offsetting the radial force component. Optionally, the inner wall of the petal-shaped clamps 3 can be provided with anti-slip texture to increase friction.

[0038] The number of devices and processing scale described herein are for the purpose of simplifying the description of this utility model. Applications, modifications, and variations of this utility model will be readily apparent to those skilled in the art.

[0039] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A pre-positionable elastic chuck, characterized in that, include: Locking sleeve (2), the locking sleeve (2) is a cylindrical structure with one end open, and a locking sleeve through hole (210) is provided at the center of the closed end of the locking sleeve (2), and the workpiece (1) is coaxially inserted into the locking sleeve through hole (210); The push shaft (6) enters from the open end of the locking sleeve (2) and is coaxially sleeved inside the locking sleeve (2). The push shaft (6) is a cylindrical body. The push shaft (6) gradually expands outward from the inner wall of the through hole (210) of the locking sleeve to form a push wedge surface (64). The positioning shaft plug (5) is a cylindrical body coaxially sleeved inside the push shaft (6) and open at one end, with its open end facing the locking sleeve through hole (210). The inner cylinder of the positioning shaft plug (5) matches the cross section of the workpiece (1). A number of petal-shaped chucks (3) are arranged in a circular pattern between the locking sleeve through hole (210) and the push shaft (6). There is a movable gap between the petal-shaped chucks (3) and they can open outward or close inward. The inner wall of the petal-shaped chucks (3) is matched and in contact with the workpiece (1). The outer wall of the petal-shaped chucks (3) gradually shrinks inward towards the push shaft (6) to form a chuck wedge surface (32) that matches the push wedge surface (64). Under the action of the axial force of the push shaft (6), the petal-shaped chucks (3) abut against the area around the locking sleeve through hole (210). The petal-shaped chucks (3) are closed inward by the push wedge surface (64) and together clamp the workpiece (1).

2. The pre-positionable elastic clamp as described in claim 1, characterized in that, The outer wall of the petal-shaped chuck (3) has a chuck retainer (31) extending out. The locking sleeve (2) has several screw holes (22) with a stop screw (4) inserted into each screw hole (22). When the end of the petal-shaped chuck (3) abuts against the locking sleeve (2), the stop screw (4) extends into the end of the locking sleeve (2) and blocks the chuck retainer (31), preventing the petal-shaped chuck (3) from moving axially.

3. The pre-positionable elastic clamp as described in claim 1, characterized in that, The open end of the positioning shaft plug (5) extends radially outward through the annular flange (51), and the inner wall of the push shaft (6) is provided with an annular groove (62) with a width greater than the thickness of the annular flange (51), and the annular flange (51) is located in the annular groove (62).

4. The pre-positionable elastic clamp as described in claim 1, characterized in that, The pusher wedge surface (64) is an inner conical surface, and the clamp wedge surface (32) is an outer conical surface.

5. The pre-positionable elastic clamp as described in claim 4, characterized in that, The pushing wedge surface (64) has a blocking ring plate (63) extending inward from the edge inside the pushing shaft (6). The end of the lobed chuck (3) facing the blocking ring plate (63) has a top-abutting end surface (33). When the chuck wedge surface (32) is in contact with the pushing wedge surface (64), the top-abutting end surface (33) abuts against the blocking ring plate (63).

6. The pre-positionable elastic clamp as described in claim 3, characterized in that, The push shaft (6) is provided with a vent hole (61) on the cylinder wall on the side away from the workpiece (1) of the positioning shaft plug (5).

7. The pre-positionable elastic clamp as described in claim 1, characterized in that, The number of the flap clips (3) is 6.

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