Hydraulic chuck with easily shaped jaws

Abstract

The present invention relates to a hydraulic chuck capable of molding a soft jaw without an additional molding ring, and discloses a hydraulic chuck as an embodiment, which is a hydraulic chuck having a main jaw capable of sliding radially with respect to a chuck housing and a soft jaw combined with the main jaw, a molding cover rotatably fitted to a central hole of the chuck housing, a periphery of the molding cover having a receiving part receiving the main jaw for a clamping operation and a contact part having a diameter larger than that of the receiving part, the main jaw being caught by the contact part according to a difference in an angle of rotation of the molding cover, thereby defining a distance of the main jaw from a release clamping position to a clamping position.

Description

Technical Field

[0001] This invention relates to a hydraulic chuck for clamping workpieces in machining, and to a hydraulic chuck capable of forming soft jaws even without an additional forming ring. Background Technology

[0002] A hydraulic chuck in a machine tool, which holds the material (workpiece) to be machined, has jaws that hold the outer or inner diameter of the workpiece. A soft jaw refers to a set of jaws that are separately engaged on the main jaw (or "base jaw"). Hydraulic chucks with a structure that combines the main jaw and soft jaws can machine the soft jaws according to the shape of the workpiece, making them suitable for small-batch, high-variety machining.

[0003] A gap is generated in a hydraulic chuck, which consists of multiple moving parts. This gap is necessary for the jaws to perform clamping / unclamping operations, but it is also a factor that hinders high-precision machining operations.

[0004] To securely grip the workpiece and improve machining accuracy, each soft jaw is assembled onto the main jaw and then shaped according to the shape of the workpiece.

[0005] At this point, a forming ring of appropriate size is used according to the dimensions of the workpiece. Specifically, in order to form the soft jaw, the main jaw is first placed in the unclamped position, and the soft jaw is set on the main jaw according to the approximate shape of the workpiece (e.g., outer diameter).

[0006] The position of the soft jaw fixed to the main jaw is set according to the shape of the workpiece so that the distance from the unclamped position to the clamped position is as short as possible.

[0007] At this point, in the prior art, the main jaw or soft jaw grips the forming ring corresponding to the shape of the workpiece to fix the position of the soft jaw. The front end of the soft jaw, which is gathered in the middle of the chuck, is bored to adjust its size. Afterward, the soft jaw is moved to the unclamped position, the forming ring is removed, and the workpiece is gripped by the soft jaw to confirm whether the machining of the soft jaw is correct.

[0008] Korean Utility Model No. 20-0143395 discloses a set of forming rings of various sizes for forming soft claws.

[0009] In addition, Korean Patent No. 10-1714476 discloses a special accessory for defining the clamping position of the main claw. This special accessory is a rod that can be detachably connected to the cover. Furthermore, Korean Patent No. 10-1135514 discloses a molded ring with a complex outer peripheral shape.

[0010] In addition, Korean Patent No. 10-1335381 discloses a structure with a scale indicating the rotation angle of the chuck housing, and Korean Patent Publication No. 10-2017-0140240 proposes a wiper blade disposed between the chuck body and the main gripper to prevent foreign matter from penetrating.

[0011] Furthermore, there is a free forming method that does not use forming rings in shaping the front ends of the soft jaws according to the workpiece. In this case, the position of the soft jaws is fixed by operating a plunger located inside the hydraulic chuck to the end of the operating range. That is, it is a method of machining the soft jaws according to the size of the workpiece with the soft jaws in their most open state.

[0012] In this case, there are no steps such as gripping the forming ring, thus greatly shortening the processing time of the soft jaws. However, since the workpiece must be machined to a certain size larger than the workpiece dimensions for the soft jaws to hold it, it is not a precision machining process that matches the shape of the workpiece. Therefore, there is a limitation that soft jaws cannot hold workpieces with high precision. Summary of the Invention

[0013] Technical issues

[0014] For the molding rings used in the existing technology, there are problems with the management and handling of the molding rings, such as the need to prepare multiple sizes according to the size of the workpiece to be processed, and the need for skilled workers to select the appropriate size molding rings, etc.

[0015] Furthermore, when processing different types of workpieces, the soft jaws need to be replaced accordingly. Each time this happens, assembly errors are usually considered when reassembling the forming ring and then reprocessing the soft jaws. At this point, the forming ring used during the previous soft jaw assembly must be re-engaged in the jaws to minimize additional machining. This requires managing the jaws and forming rings in pairs, which is very cumbersome. This is especially problematic in factories with large-scale production equipment that have a large number of jaws and several forming rings of the same size.

[0016] The present invention is intended to solve the above-mentioned problems and aims to eliminate the trouble of managing the forming ring by enabling the forming of claws without the forming ring, thereby simplifying the claw forming operation and enabling the workpiece to be clamped with high precision.

[0017] Experts or researchers in this field will clearly understand the specific objectives of other inventions through the following detailed description.

[0018] Technical solution

[0019] To achieve the above objectives, the present invention provides, as an embodiment, a hydraulic chuck with easily formable claws. This hydraulic chuck has a plurality of main claws capable of radially sliding relative to a chuck housing and soft claws coupled to each of the main claws. The characteristic feature is that a forming cover is rotatably mounted in the central hole of the chuck housing. The periphery of the forming cover has a receiving portion for accommodating the main claws performing clamping operations and a contact portion with a diameter larger than the receiving portion. When the forming cover is rotated such that the contact portion faces the main claw, the main claw interferes with the contact portion, thereby limiting the distance the main claw can move from a released clamping position to a clamping position.

[0020] The contact surface of the main claw that contacts the contact portion can be a curved surface corresponding to the contact portion.

[0021] In addition, a stop mechanism is provided to limit the rotation angle of the molded cover, thereby preventing the molded cover from rotating arbitrarily without the user's intention.

[0022] Furthermore, the contact portion can be configured such that its diameter gradually increases along one direction, and the distance the main jaw moves from the unclamped position to the clamped position can vary depending on the rotation angle of the forming cover. The time required to fix the workpiece can be finely adjusted according to the processing schedule, thus contributing to optimized process automation.

[0023] Furthermore, the molded cover has an indicator portion that indicates the rotation angle of the molded cover, so that the user can easily identify the rotation state of the molded cover.

[0024] As part of the assembly of the molded cover, a recessed assembly groove is formed on the inner circumferential surface of the central hole, the molded cover is rotatably disposed in the assembly groove, and the hydraulic chuck may have a guide plate that is coupled to the chuck housing and covers the edge of the molded cover.

[0025] In addition, to prevent contamination from foreign matter generated during processing, the chuck housing may have a scraper to remove foreign matter from the outer side of the contact portion.

[0026] Technical effect

[0027] According to embodiments of the present invention, the efficiency of the jaw forming operation can be improved whenever the jaw is changed. Furthermore, productivity is improved by saving the time required to clamp / unclamp the workpiece, while simultaneously enabling precise clamping of the workpiece, thus improving processing quality.

[0028] Experts or researchers in this field can clearly understand the effects of other inventions through the specific details described below. Attached Figure Description

[0029] Figure 1This is a simplified perspective view of a hydraulic chuck with easily formable claws according to an embodiment of the present invention.

[0030] Figure 2 It is based on separation Figure 1 A perspective view of the main part of the hydraulic chuck in the embodiment shown.

[0031] Figure 3 yes Figure 1 The illustrated embodiment shows a perspective view of the molded cap used.

[0032] Figure 4 yes Figure 3 The front view of the molded cap is shown.

[0033] Figure 5 yes Figure 1 The front view of the hydraulic chuck shown.

[0034] Figure 6 It is shown Figure 1 The front view of the main part of the hydraulic chuck shown.

[0035] Figure 7 It is a brief illustration Figure 1 The front view shows the hydraulic chuck in use.

[0036] Figure 8a and Figure 8b It is a brief illustration Figure 1 The diagram shows another usage state of the hydraulic chuck.

[0037] Figure 9a and Figure 9b It is a brief illustration Figure 1 The diagram shows another usage state of the hydraulic chuck. Detailed Implementation

[0038] The following description, with reference to the accompanying drawings, illustrates the structure, function, and operation of the hydraulic chuck with easily formable claws according to the present invention. However, reference numerals for the same or similar structures are used consistently throughout the drawings.

[0039] The accompanying drawings illustrate embodiments to which the present invention is applicable, but should not be interpreted as limiting the technical concept of the invention. It is permissible for an expert in the art to interpret that some or all of the shapes, patterns, or sequences shown in the drawings are not essential for carrying out the invention, and therefore the invention as described in the claims is not limited.

[0040] Figure 1 This is a simplified perspective view of a hydraulic chuck according to an embodiment of the present invention.

[0041] The hydraulic chuck 100 according to the illustrated embodiment has a cylindrical chuck housing 10, three main jaws 20 arranged radially on the front surface of the chuck housing 10, and soft jaws 30 detachably coupled to each main jaw 20.

[0042] In the illustrated embodiment, the soft claw 30 is fixed by engaging with a thread 22 located on the front of the main claw 20, and by the combination of a T-shaped nut component 31 and a screw on the main claw 20. Various modifications to the fixing method of the soft claw are also possible.

[0043] The main jaws 20 move towards the center of the chuck housing 10 (clamping operation) or open to each other (unclamping operation) through the forward and backward movement of the plunger (not shown) located inside the chuck housing 10.

[0044] A central hole 11 is formed in the center of the chuck housing 10, which extends through the chuck housing 10 from front to back, and the molded cover 40 is rotatably fitted into the central hole 11.

[0045] The molded cap 40 can replace the existing molded ring by interfering with the clamping operation of the main claw 20 or by releasing the interference depending on the rotation angle.

[0046] To rotate the molded cover 40 by a predetermined angle, a slot 401 with a non-circular cross-section can be formed in front of the molded cover, and a hand tool such as a wrench k can be mounted in the slot 401. At this time, multiple slots 401 can be formed in multiple positions so that the hand tool can be mounted on the molded cover 40 while avoiding interference from the soft claw.

[0047] Figure 2 This diagram shows the chuck housing and the molding cover separated. Figures 3 to 4 The illustration shows a molded cap.

[0048] The molded cap 40 is an annular (doughnut) shape with a predetermined thickness and is rotatably fitted into a mounting groove 12 that is recessed into a circle along the inner side of the central hole 11.

[0049] Each main jaw 20 is guided so that the sliding groove 13, which slides radially relative to the chuck housing, connects to the mounting groove 12. In the workpiece clamping position, the front end of the main jaw extends further into the center of the chuck housing than the inner side of the mounting groove (see reference). Figure 7 ).

[0050] In addition, after the molded cover 40 is rotatably mounted in the mounting slot 12, a guide plate 50 that covers the edge of the molded cover 40 is attached to the chuck housing 10.

[0051] The guide plates 50 are arc-shaped, and the three guide plates 50 are clustered together to form an approximate circle. However, the guide plates 50 are designed not to obstruct the area where the main jaw moves so as not to interfere with the clamping / unclamping operation. The guide plates 50 are positioned corresponding to the arc-shaped section of the assembly slot 12, and the main jaw can move between the guide plates 50.

[0052] refer to Figure 6 The enlarged view shows the cross-section AA. A guide plate 50, positioned along the periphery of the assembly groove 12, covers the edge of the molding cover 40 fitted into the assembly groove, thus preventing foreign objects from entering between the assembly groove 12 and the molding cover 40. Simultaneously, it secures the molding cover 40 to prevent it from detaching from the assembly groove 12.

[0053] Furthermore, the guide plate 50 is marked with scale 51 and scale value 52, thus visually showing the indicator 402 of the molded cover 40 and the moving distance of the main claw according to the rotation angle of the molded cover.

[0054] Depending on the different structures in which the molded cover is integrated into the chuck housing, this guide plate 50 can be omitted or replaced with other components.

[0055] refer to Figure 3 and Figure 4 The outer periphery of the molding cover 40 has a receiving portion 41 for accommodating the main claw during clamping operation and a contact portion 42 with a diameter larger than the receiving portion 41.

[0056] According to the configuration structure of the main claw, multiple receiving portions 41 are formed at equal intervals, and the contact portion 42 is located between adjacent receiving portions 41.

[0057] Each receiving portion 41 is a wide groove recessed from the outer periphery of the forming cover 40 towards the center, thereby ensuring that it does not interfere with the main jaws during the clamping operation. The clamping operation is an operation in which the soft jaws, in their maximum open state, converge toward the center of the chuck housing in order to clamp the workpiece. When the soft jaws clamp the workpiece, the main jaws, which are integrated with the soft jaws, enter the receiving portion, thereby not contacting the forming cover.

[0058] Furthermore, the contact portion 42 is formed with a diameter larger than that of the receiving portion 41. As the rotation angle of the molding cover 40 is adjusted, the contact portion 42 is located within the range of movement of the main jaw, at which point the main jaw, which performs the clamping operation, interferes with the contact portion 42. As the main jaw is gripped by the contact portion 42, the distance the main jaw moves from its open position to its maximum extent (the position where the clamping is released) in order to grip and fix the workpiece (hereinafter referred to as the 'grip distance') is limited.

[0059] That is, during the clamping operation, the main jaw 20 interferes with the forming cover (contact portion) and is thus fixed in position, thereby performing the forming of the soft jaw attached to the main jaw. After the soft jaw is formed, the receiving portion 41 of the forming cover 40 is rotated to align with the moving groove of the main jaw. The workpiece can then be clamped by the clamping operation of the hydraulic chuck. The soft jaw fixes / releases the workpiece by moving an amount equivalent to the biting distance, thus minimizing the time required to fix / release the workpiece.

[0060] As shown above, the forming cap is held in place by the main jaws and the soft jaws are fixed in the forming position, thus the forming cap can replace the forming ring according to the prior art.

[0061] The outer periphery of the molded cap 40 is formed as a curved surface. Therefore, the contact surface 21 formed at the front end of the main claw 20 that contacts the contact portion 42 can also be formed as a curved surface corresponding to the contact portion 42. As the contact surface 21 of the main claw 20 contacts the contact portion 42, the main claw can be stably gripped.

[0062] Furthermore, the molded cover 40 has an indicator 402 that shows the rotation angle of the molded cover. The indicator 402 can be formed on the front side of the molded cover 40 using an arrow or a length groove.

[0063] In the illustrated embodiment, the indicator 402 is formed at the bottom center of the receiving portion 41, and its position is chosen so that it is not obscured by the guide plate 50 even when the molding cover 40 is rotated, thus allowing it to be easily seen from the outside. The user can visually check the indicator 402 to confirm whether the moving groove of the main claw is aligned with the receiving portion or with the contact portion.

[0064] In addition, except when molding the soft claw, the receiving portion 41 of the molding cover 40 should be kept aligned with the moving groove 13 of the main claw 20. A stop mechanism can be included to limit the rotation angle of the molding cover 40 so that the molding cover 40 does not rotate arbitrarily as described above.

[0065] refer to Figure 6 It can be configured such that a few recessed grooves 403 are formed on the bottom surface of the molded cover 40 that contacts the ground of the assembly groove 12, and a ball plunger 14 is provided at the position through which the groove passes in the assembly groove 12, so that when the molded cover 40 is aligned at a specific angle, such as when the receiving part 41 is aligned with the main claw, the ball head of the ball plunger 14 enters any of the grooves 403.

[0066] Furthermore, bolt holes 404 can be formed through the forming cap 40 in a location not obstructed by guide plates or the like. A bolt (not shown) can be attached to any one of these bolt holes 404, pushing the forming cap away from the mounting groove to secure it and prevent rotation. This prevents unintended rotation of the forming cap during repeated securing of numerous workpieces after the soft claw is formed.

[0067] Regarding such a stopper mechanism such as the groove 403 and the ball plunger 14 or the bolt hole 404, various configurations can be changed on the premise that the formed cover does not rotate arbitrarily.

[0068] Refer again to Figure 4 , the radius length of the contact portion 42 changes along the periphery of the formed cover 40, and according to the different rotation angles of the formed cover 40, the biting distance of the main claw is different.

[0069] In the figure, the radius of the contact portion 42 gradually increases along the outer peripheral surface from one accommodating portion to the adjacent accommodating portion (r1 < r2 < r3 < r4). At this time, the edge of the contact portion 42 forms a gentle curved surface, so the formed cover 40 can contact the contact surface of the main claw at any rotation angle.

[0070] At this time, in all the radially arranged contact portions, the shape is such that the diameter of the contact portion 42 increases in the same direction (counterclockwise in the figure), so all the main claws meet the contact portion part with the same diameter.

[0071] The contact portion 42 with a gradually increasing diameter makes the biting distance required for the main claw to move from the release clamping position to the position of biting and fixing the workpiece vary according to the rotation angle of the formed cover 40, which will be described later.

[0072] In a premise embodiment not shown, the contact portion can be formed into a certain one diameter.

[0073] As an additional configuration, refer to Figure 5 , the chuck housing 10 has a scraper 16 for removing foreign matter on the outer side of the contact portion.

[0074] A sliding groove 15 is formed on the chuck housing 10 toward the inner wall of the fitting groove 12, and the scraper 16 elastically supported by a spring 151 is fitted in the sliding groove 15.

[0075] The front end portion of the scraper 16 is elastically supported to contact the periphery of the contact portion 42 to remove foreign matter attached to the periphery of the contact portion 42 when the formed cover 40 rotates. A plurality of such scrapers are radially provided around the formed cover 40 to protect each contact portion 42 from foreign matter.

[0076] Figures 7 to 8b Relates to the use state of the hydraulic chuck.

[0077] Figure 7 It is a state where the formed cover 40 rotates until the accommodating portion 41 of the formed cover 40 aligns with the moving groove 13 of the hydraulic chuck 10. The user can know the current rotation position of the formed cover 40 by visually confirming that the indicating portion 402 formed in the accommodating portion 41 is arranged in the direction pointing to the main claw 20.

[0078] In this state, the main jaw 20 and the soft jaw attached thereto can perform clamping / unclamping operations without interfering with the forming cap 40.

[0079] in addition, Figures 8a to 9b The state is such that the contact part 42 interferes with the main claw 20 when the molded cover 40 rotates at different angles.

[0080] The guide plate 50 is marked with a scale 51 and a scale value 52 indicated by the indicator 402. The scale 51 is marked according to the degree of rotation of the molding cover 40, and the scale value 52 indicates the biting distance from the release position to when the main claw (soft claw) is bitten and fixed by the molding cover.

[0081] Figure 8a and Figure 8b The molded cap 40 has rotated approximately 45°, so that the middle portion of the contact portion 42 contacts the main claw 20. The main claw moves from its fully open, released position by an amount equivalent to the biting distance D1, thereby fixing its position by the contact portion 42.

[0082] In this state, the soft claw is formed. After forming, the forming cover is rotated back to its original position so that the receiving part is aligned with the main claw (reference). Figure 7 Then the soft jaw (main jaw) moves back and forth, moving the biting distance D1 shown in the diagram to fix / release the workpiece.

[0083] Figure 9a and Figure 9b The molded cap 40 is in a state where it has rotated approximately 75°. The larger diameter portion of the contact portion 42 contacts the main claw 20, therefore the main claw 20 moves from its open to its maximum release position to a biting distance D2 where it is gripped by the molded cap 40, which is greater than... Figure 8a Short (D2) <D1)。

[0084] As the bite distance D2 becomes shorter, the time required for the soft claw to fix / release the workpiece becomes shorter.

[0085] By rotating the molding cap 40 to the appropriate angle as described above, the user can select the diameter of the contact portion 42 that grips the main claw 20 for fixation. This allows the user to vary the time required to fix / release the workpiece, providing the same performance as using molding rings of various sizes.

[0086] According to embodiments of the present invention, it is possible to omit the additional forming ring required for fixing the position of the soft claw during the forming process. Therefore, the various sizes of forming rings required in the prior art, depending on the size of the workpiece, can be eliminated.

[0087] Furthermore, resetting previously used claws is equivalent to reusing the same molded cover on the hydraulic chuck, thus minimizing the number of parts and time required for reprocessing and replacing claws, and shortening the time required for pre-processing preparation.

Claims

1. A hydraulic chuck with easily formable claws, comprising a plurality of main claws capable of radially sliding relative to a chuck housing and soft claws coupled to each of the main claws, characterized in that: The molded cover is rotatably fitted into the central hole of the chuck housing. The outer periphery of the molded cover has a receiving portion for accommodating the main claw for clamping operations and a contact portion with a diameter larger than the receiving portion. When the molded cover is rotated to an angle such that the contact portion faces the main claw, the main claw interferes with the contact portion, thereby limiting the distance the main claw moves from the unclamped position to the clamped position.

2. The hydraulic chuck with easily formed claws according to claim 1, characterized in that: The contact surface of the main claw that contacts the contact portion is a curved surface corresponding to the contact portion.

3. The hydraulic chuck with easily formed claws according to claim 1, characterized in that: A stop mechanism is provided that limits the rotation angle of the molded cover.

4. The hydraulic chuck with easily formed claws according to claim 1, characterized in that: The diameter of the contact portion gradually increases in one direction, and the distance the main claw moves from the unclamped position to the clamped position varies depending on the rotation angle of the molded cover.

5. The hydraulic chuck with easily formed claws according to claim 4, characterized in that: The molded cover has an indicator portion that indicates the rotation angle of the molded cover.

6. The hydraulic chuck with easily formable claws according to any one of claims 1 to 5, characterized in that: A recessed mounting groove is formed on the inner circumferential surface of the central hole, and the molded cover is rotatably disposed in the mounting groove. The hydraulic chuck has a guide plate that is attached to the chuck housing and covers the edge of the molded cover.

7. The hydraulic chuck with easily formable claws according to any one of claims 1 to 5, characterized in that: The chuck housing has a scraper to remove foreign matter from the outer side of the contact portion.

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