Hydraulic chuck that enables easy jaw forming

Abstract

The present invention relates to a hydraulic chuck capable of forming a soft jaw without a separate forming ring, and as an embodiment, the hydraulic chuck includes a master jaw capable of sliding radially relative to a chuck housing and a soft jaw coupled to the master jaw, in which a forming cover is rotatably mounted in a central hole of the chuck housing, and a receiving portion in which the master jaw that performs a clamping operation is received and a contact portion having a larger diameter than the receiving portion are provided around the forming cover, and the master jaw clamps the contact portion depending on an angle at which the forming cover is rotated, thereby limiting the distance the master jaw moves from an unclamping position to a clamping position.

Description

Technical Field

[0001] The present invention relates to a hydraulic chuck for gripping a workpiece by machining, and more particularly to a hydraulic chuck capable of forming a soft jaw without separately providing a forming ring.

Background Art

[0002] A hydraulic chuck for gripping a workpiece (workpiece) to be machined by a machine tool includes a jaw for gripping the outer diameter or inner diameter of the workpiece. A plurality of soft jaws refer to a set of jaws that are separately coupled to a plurality of master jaws (or referred to as "a plurality of base jaws"). A hydraulic chuck having a structure for coupling a plurality of master jaws and a plurality of soft jaws is suitable for small-lot and multi-variety machining because the soft jaws can be machined according to the shape of the workpiece.

[0003] In a hydraulic chuck in which a plurality of components are assembled and these components move to operate, play occurs. Such play is an essential element for the clamping / unclamping operation of a plurality of jaws, and on the other hand, it is also an element that hinders high-precision machining operations.

[0004] For the purpose of firmly gripping the workpiece and improving the machining accuracy, after each soft jaw is attached to the master jaw, the soft jaw is formed according to the shape of the workpiece.

[0005] At this time, a forming ring of an appropriate size is used according to the size of the workpiece. Specifically, for forming the soft jaw, first, the master jaw is placed at the unclamping position, and the soft jaw is installed on the master jaw according to the approximate shape (e.g., outer diameter) of the workpiece.

[0006] Here, the positions where a plurality of soft jaws are fixed to a plurality of master jaws are set in consideration of the shape of the workpiece so that the distance of movement from the unclamping position to the clamping position is as short as possible.

[0007] In this case, in the conventional technology, a forming ring corresponding to the shape of the workpiece is clamped to a plurality of master jaws or a plurality of soft jaws to fix the positions of the plurality of soft jaws, and the tip portions of the plurality of soft jaws gathered at the center of the chuck are bored to adjust the size. Thereafter, the plurality of soft jaws are moved to the unclamping position, and after removing the forming ring, the workpiece is clamped to the plurality of soft jaws to check whether the machining of the plurality of soft jaws has been correctly performed.

[0008] Republic of Korea Utility Model Registration No. 20-0143395 discloses a set of forming rings of various sizes used for forming a plurality of soft jaws.

[0009] On the other hand, Republic of Korea Patent Registration No. 10-1714476 discloses a dedicated accessory for limiting the clamping positions of a plurality of master jaws. This dedicated accessory is a plurality of rods detachably coupled to a cover. Also, Republic of Korea Patent Registration No. 10-1135514 discloses a forming ring having a complex-shaped outer peripheral surface.

[0010] On the other hand, Republic of Korea Patent Registration No. 10-1335381 shows a configuration in which a scale indicating the rotation angle of the chuck housing is engraved, and Republic of Korea Patent Publication No. 10-2017-0140240 discloses a wiper blade provided between the chuck body and the master jaw to prevent the penetration of foreign matter.

[0011] Furthermore, when forming the tip portions of a plurality of soft jaws to fit the workpiece, there is a free forming method that does not use a forming ring. Here, the position fixing of the plurality of soft jaws is obtained by operating a plunger provided inside the hydraulic chuck to the end of the operating section. That is, it is a method of opening the plurality of soft jaws to the maximum and machining the soft jaws according to the size of the workpiece.

[0012] In this case, since there is no step such as clamping the forming ring, the processing time of multiple soft jaws is significantly shortened. However, if the soft jaws are not processed to a size that is somewhat larger than the size of the workpiece, the multiple soft jaws will not be able to grip the workpiece, so it will no longer be precise processing according to the shape of the workpiece. As a result, there is a limit to the ability of multiple soft jaws to grip the workpiece with high precision.

Summary of the Invention

Problems to be Solved by the Invention

[0013] The forming rings used in the conventional technology must be prepared in multiple numbers according to the size of the workpiece to be processed, and a skilled person must select a forming ring of an appropriate size, etc., which is troublesome in the management and handling of the forming rings.

[0014] Also, when changing to workpieces of different types, multiple soft jaws are also replaced accordingly. In this case, it is common to reprocess the multiple soft jaws by attaching a forming ring in consideration of assembly errors, etc. each time. In this case, additional processing can be minimized by reclamping the forming ring used in the previous soft jaw attachment to multiple jaws, but for this purpose, there is the trouble of having to manage the combination of multiple jaws and the forming ring. Especially in a factory equipped with mass production facilities, since multiple forming rings are held even for a large number of jaws of the same size, such trouble is even greater.

[0015] The present invention is for solving the above-described problems, and by enabling forming without a forming ring, it eliminates the trouble of having to manage the forming ring, simplifies the forming operation, and enables the workpiece to be gripped with high precision.

[0016] In addition, the detailed objects of the present invention will be clearly understood and grasped by experts and researchers in this technical field through the specific content described below.

Means for Solving the Problems

[0017] In order to solve the above problems, as an embodiment, the present invention provides a hydraulic chuck including a plurality of master jaws that can slide radially with respect to a chuck housing and soft jaws coupled to each of the master jaws. A forming cover is rotatably mounted in a central hole of the chuck housing, and a housing portion for accommodating the master jaws that perform a clamping operation is provided around the forming cover, and a contact portion having a diameter larger than that of the housing portion is provided. At an angle at which the forming cover rotates so that the contact portion faces the master jaw, the master jaw interferes with the contact portion, and the distance that the master jaw moves from the unclamping position to the clamping position is limited. A hydraulic chuck with easy jaw forming is disclosed.

[0018] Here, the contact surface of the master jaw in contact with the contact portion can be a curved surface corresponding to the contact portion.

[0019] Further, a stop means for limiting the rotation angle of the forming cover is provided, so that the forming cover does not rotate arbitrarily without the intention of the user.

[0020] Furthermore, the contact portion can be configured such that the diameter gradually increases along one direction, and the distance that the master jaw moves from the unclamping position to the clamping position changes according to the rotation angle of the forming cover. This allows for fine adjustment of the time required to fix the workpiece according to the machining operation schedule, which is useful for optimizing the process automation.

[0021] Furthermore, the forming cover is provided with an indicating portion indicating the rotation angle of the forming cover, so that the user can easily recognize the rotation state of the forming cover.

[0022] A structure for mounting a forming cover, wherein a mounting groove on the inner peripheral surface of the central hole is formed so as to recess, on which the forming cover is rotatably placed, and a guide plate can be provided which is coupled to the chuck housing and covers and hides the edge of the forming cover.

[0023] In addition, in order to prevent contamination by foreign matter generated during processing, the chuck housing can be provided with a scraper for removing foreign matter on the outer side of the contact portion.

Advantages of the Invention

[0024] According to an embodiment of the present invention, the efficiency of the jaw forming operation associated with each alternation of the jaws can be improved. In addition, the time taken for clamping / unclamping the workpiece can be reduced to improve productivity while precisely gripping the workpiece, and the processing quality can be improved.

[0025] In addition, the effects of the present invention will be self-evidently grasped and understood by experts and researchers in this technical field through the specific content described below or in the process of implementing the present invention.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8a

Figure 8b

Figure 9a

Figure 9b

Embodiments for Carrying Out the Invention

[0027] Hereinafter, with reference to the accompanying drawings, the configuration, function, and operation of a hydraulic chuck that facilitates jaw forming according to the present invention will be described. However, the same or similar drawing numbers for the components in each drawing will be used uniformly.

[0028] The attached drawings show the applied embodiments of the present invention, and the technical idea of the present invention should not be construed in a limited manner by the attached drawings. From the perspective of experts in this technical field, if it can be interpreted that some or all of what is illustrated in the drawings is not necessarily required in the shape, pattern, and order for the implementation of the invention, this does not limit the invention described in the claims.

[0029] Fig. 1 is a schematic perspective view of a hydraulic chuck according to an embodiment of the present invention.

[0030] The hydraulic chuck (100) according to the illustrated embodiment includes a cylindrical chuck housing (10), three master jaws (20) radially located on the front surface of the chuck housing (10), and soft jaws (30) detachably coupled to each master jaw (20).

[0031] In the illustrated embodiment, the fixing method of the soft jaw (30) is such that the soft jaw (30) meshes through the thread (22) provided on the front surface of the master jaw (20), and is fixed to the master jaw (20) by the combination of a T-shaped nut member (31) and a bolt attached to the master jaw (20). Different from this, the fixing method of the soft jaw can be changed in various ways.

[0032] The master jaw (20) moves forward and backward by a plunger (not shown) provided in the chuck housing (10), and gathers at the center of the chuck housing (10) (clamping operation) or opens so as to be separated from each other (unclamping operation).

[0033] A central hole (11) penetrating the chuck housing (10) front and back is formed at the center of the chuck housing (10), and a forming cover (40) is rotatably mounted in this central hole (11).

[0034] This forming cover (40) can replace the conventional forming ring by interfering with or releasing the interference of the clamping operation of the master jaw (20) according to the rotation angle.

[0035] In order to rotate the forming cover (40) at an appropriate angle, a fitting groove (401) with a non-circular cross-section is formed in front of the forming cover, and a hand tool such as a wrench (k) can be mounted in this fitting groove (401). At this time, a plurality of fitting grooves (401) are formed in a large number in a plurality of directions so that the hand tool can be mounted on the forming cover (40) while avoiding interference with the soft jaw.

[0036] Figure 2 shows the chuck housing and the forming cover separated, and Figures 3 to 4 show the forming cover.

[0037] The forming cover (40) has a donut shape with a predetermined thickness and is rotatably mounted in a mounting groove (12) formed circularly and recessed along the inside of the central hole (11).

[0038] A moving groove (13) that guides each master jaw (20) so that it slides radially relative to the chuck housing is connected to the mounting groove (12). When the master jaw is in the position to grip the workpiece, the tip of the master jaw advances further from the inside of the mounting groove toward the center of the chuck housing (see Figure 7).

[0039] Meanwhile, after the molding cover (40) is rotatably mounted in the mounting groove (12), a guide plate (50) for covering and hiding the edge of the molding cover (40) is coupled to the chuck housing (10).

[0040] The guide plates (50) are arc-shaped, and three of them come together to form an approximately circular shape. However, the guide plates (50) do not cover the area in which the master jaws move so as not to interfere with the clamping / unclamping operation of the master jaws. The guide plates (50) are installed in correspondence with the arc-shaped section of the mounting groove (12), and the master jaws can move between the guide plates (50).

[0041] 6, the guide plate (50) installed along the periphery of the mounting groove (12) covers and hides the edge of the molded cover (40) mounted in the mounting groove, thereby preventing foreign objects from entering between the mounting groove (12) and the molded cover (40). At the same time, it also confines the molded cover (40) so that it does not come off the mounting groove (12).

[0042] In addition, a scale (51) and scale values ​​(52) are displayed on the upper surface of the guide plate (50), which, together with an indicator portion (402) of the molding cover (40) described later, visually indicates the distance the master jaw moves depending on the rotation angle of the molding cover.

[0043] The guide plate 50 may be omitted or replaced with another structure depending on the structure in which the molded cover is coupled to the chuck housing.

[0044] Refer to FIGS. 3 and 4. Around the molding cover (40), there is a receiving portion (41) for accommodating the master jaw during the clamping operation, and a contact portion (42) having a diameter larger than that of the receiving portion (41).

[0045] A plurality of receiving portions (41) are formed at equal intervals according to the arrangement structure of the master jaw, and the contact portion (42) is located between adjacent receiving portions (41).

[0046] Each receiving portion (41) is in the form of a wide-width groove recessed from the outer peripheral surface of the molding cover (40) toward the center so as not to interfere with the master jaw during the clamping operation. Here, the clamping operation is an operation in which the soft jaws in the fully open state gather at the center of the chuck housing to grip the workpiece. When the soft jaws grip the workpiece, the master jaw integrally coupled to the soft jaws does not enter the receiving portion and come into contact with the molding cover.

[0047] On the other hand, the contact portion (42) is a portion formed with a diameter larger than that of the receiving portion (41). By adjusting the rotation angle of the molding cover (40), the contact portion (42) is positioned in the section where the master jaw moves. At this time, the master jaw during the clamping operation is interfered by the contact portion (42). By clamping the master jaw against the contact portion (42), the distance (hereinafter referred to as the "clamp distance") that the master jaw moves to clamp and fix the workpiece from the position where it is fully open (unclamped position) is limited.

[0048] That is, the master jaw (20) is interfered with the molding cover (contact portion) and its position is fixed during the clamping operation, and the soft jaw coupled to the master jaw is molded in this state. After the molding of the soft jaw is completed, the receiving portion (41) of the molding cover (40) is rotated so as to align with the movement groove of the master jaw. Thereafter, the workpiece can be gripped by the clamping operation of the hydraulic chuck. The soft jaw can minimize the time required for fixing / releasing the workpiece by moving while fixing / releasing the workpiece by the clamp distance.

[0049] By fixing the soft jaw at the forming position while the forming cover is clamped to the master jaw in this way, the forming cover can replace the forming ring according to the conventional technology.

[0050] The forming cover (40) has a curved outer periphery. Thereby, the grounding surface (21) formed at the tip of the master jaw (20) that comes into contact with the contact portion (42) can also be formed as a curved surface corresponding to the contact portion (42). Stable clamping of the master jaw is possible by the grounding surface (21) of the master jaw (20) coming into surface contact with the contact portion (42).

[0051] In addition, the forming cover (40) is provided with an indicating portion (402) indicating the rotation angle of the forming cover. The indicating portion (402) can be formed by an arrow or a long groove on the front portion of the forming cover (40).

[0052] In the illustrated embodiment, the indicating portion (402) is formed at the center of the bottom of the accommodating portion (41), and is selected at a position where it is not hidden by the guide plate (50) even when the forming cover (40) rotates and can be easily seen from the outside. The user can check whether the moving groove of the master jaw and the accommodating portion are aligned or the contact portions are aligned by visually examining the indicating portion (402).

[0053] On the other hand, except when forming the soft jaw, it is necessary to maintain the state where the accommodating portion (41) of the forming cover (40) is aligned with the moving groove (13) of the master jaw (20). Stopping means for limiting the rotation angle of the forming cover (40) so that the forming cover (40) does not rotate arbitrarily can be provided.

[0054] Refer to Fig. 6. Several concave grooves (403) are formed on the bottom surface of the molding cover (40) that contacts the bottom of the mounting groove (12). A ball plunger (14) is installed in the mounting groove (12) at a position where the concave groove passes through. When the molding cover (40) is adjusted to a specific angle, for example, when the accommodating part (41) is adjusted to the master jaw, the ball of the ball plunger (14) can be configured to enter one of the concave grooves.

[0055] Furthermore, a bolt hole (404) that penetrates the molding cover (40) can be formed at a position not blocked by a guide plate or the like. A bolt (not shown) can be fastened to any of these bolt holes (404), and while the bolt presses the bottom of the mounting groove, the molding cover can be fixed so as not to rotate. After the molding of the soft jaw is completed, unintentional rotation of the molding cover can be prevented while repeatedly fixing a large number of workpieces.

[0056] Such concave grooves (403) and fixing means such as ball plungers (14) or bolt holes (404) can be changed to various configurations that prevent the molding cover from rotating arbitrarily.

[0057] Refer to Fig. 4 again. The radius length of the contact part (42) changes along the circumference of the molding cover (40), and the clamping distance of the master jaw changes according to the rotation angle of the molding cover (40).

[0058] In the drawing, the radius of the contact part (42) gradually increases along the outer peripheral surface from one accommodating part to the adjacent accommodating part (r1 < r2 < r3 < r4). Here, the edge of the contact part (42) forms a gentle curved surface, and the molding cover (40) can contact the grounding surface of the master jaw at any rotation angle.

[0059] In this case, by taking the form in which the diameter of the contact part (42) increases along the same direction (counterclockwise in the drawing) for all the radially arranged contact parts, all the master jaws will meet the part of the contact part with the same diameter.

[0060] The contact part (42) with a shape whose diameter gradually increases changes the clamping distance required for the master jaw to move from the unclamping position to the position where it clamps and fixes the workpiece according to the rotation angle of the forming cover (40), and this will be described later.

[0061] In other embodiments (not shown), the contact part can be formed with a constant single diameter.

[0062] As an additional configuration, refer to FIG. 5. The chuck housing (10) is provided with a scraper (16) for removing foreign matter from the outer part of the contact part.

[0063] A sliding groove (15) leading to the inner wall of the mounting groove (12) is formed in the chuck housing (10), and a scraper (16) elastically supported by a spring (151) is mounted in this sliding groove (15).

[0064] The tip of the scraper (16) contacts while elastically supporting around the contact part (42), thereby removing foreign matter adhering around the contact part (42) when the forming cover (40) rotates. A plurality of such scrapers are provided radially around the forming cover (40) to protect each contact part (42) from foreign matter.

[0065] FIGS. 7 to 8b are related to the usage state of the hydraulic chuck.

[0066] FIG. 7 shows a state where the forming cover (40) is rotated so that the accommodating part (41) of the forming cover (40) is aligned with the moving groove (13) of the hydraulic chuck (10). The user can know the current rotation position of the forming cover (40) by visually confirming that the indicating part (402) formed in the accommodating part (41) is placed in the direction pointing to the master jaw (20).

[0067] In this state, the master jaw (20) and the soft jaw coupled thereto can perform clamping / unclamping operations without interference from the forming cover (40).

[0068] On the other hand, FIGS. 8a to 9b show a state in which the forming cover (40) rotates at a different rotation angle from before so that the contact portion (42) interferes with the master jaw (20).

[0069] The guide plate (50) is provided with a scale (51) pointed by the indicating portion (402) and a scale value (52). Here, the scale (51) is indicated in accordance with the degree of rotation of the forming cover (40), and the scale value (52) indicates the clamping distance that the master jaw (soft jaw) moves from the unclamping position until it clamps and fixes the forming cover.

[0070] FIGS. 8a and 8b show a state in which the forming cover (40) rotates approximately 45°, and the middle portion of the contact portion (42) is in contact with the master jaw (20). The master jaw moves by a clamping distance (D1) from the fully opened unclamping position and is fixed in position by the contact portion (42).

[0071] In this state, the soft jaw is formed. After the forming is completed, the forming cover is rotated back to its original position so that the accommodating portion is aligned with the master jaw (see FIG. 7). Thereafter, the soft jaw (master jaw) reciprocates by the clamping distance (D1) shown in the drawing to fix / unfix the workpiece.

[0072] FIGS. 9a and 9b show a state in which the forming cover (40) rotates approximately 75°. The contact portion (42) comes into contact with the master jaw (20) at a portion with a larger diameter, and the clamping distance (D2) that the master jaw (20) moves from the fully opened unclamping position until the forming cover (40) is clamped is shorter than that in FIG. 8a (D2 < D1).

[0073] By making the clamp distance (D2) shorter, it then takes the soft jaw less time to fix / release the workpiece.

[0074] By rotating the forming cover (40) at an appropriate angle in this way, the user can select the diameter of the contact part (42) that is clamped and fixed to the master jaw (20). This then allows the user to vary the time taken to fix / release the workpiece, providing the same effect as using forming rings of various sizes.

[0075] According to an embodiment of the present invention, it is possible to omit a separate forming ring required to position-fix the soft jaw in the forming process of the soft jaw. As a result, it is possible to eliminate forming rings of a plurality of sizes corresponding to the size of the workpiece required in the prior art.

[0076] Also, when reinstalling a previously used jaw, the same forming cover provided on the hydraulic chuck will be reused, so the parts and time required for reprocessing the replaced jaw can be minimized, and the time required for preparation work before the main processing can be shortened.

Claims

1. In a hydraulic chuck comprising a plurality of master jaws slidably movable radially with respect to a chuck housing and a soft jaw coupled to each of the master jaws, a forming cover is rotatably mounted in a central hole of the chuck housing, around the forming cover, a receiving portion for receiving the master jaws that perform a clamping operation and a contact portion having a diameter larger than that of the receiving portion are provided, at an angle at which the forming cover rotates such that the contact portion faces the master jaws, the master jaws interfere with the contact portion and the distance by which the master jaws move from the unclamping position to the clamping position is limited, characterized in that a hydraulic chuck that is easy to form the jaws.

2. The hydraulic chuck that is easy to form the jaws according to claim 1, wherein a grounding surface of the master jaw in contact with the contact portion is a curved surface corresponding to the contact portion.

3. The hydraulic chuck that is easy to form the jaws according to claim 1, characterized in that a stop means for limiting the rotation angle of the forming cover is provided.

4. The hydraulic chuck that is easy to form the jaws according to claim 1, wherein the contact portion has a diameter that gradually increases along one direction, and the distance by which the master jaws move from the unclamping position to the clamping position changes according to the rotation angle of the forming cover.

5. The hydraulic chuck that is easy to form the jaws according to claim 4, characterized in that the forming cover is provided with an indicating portion indicating the rotation angle of the forming cover.

6. On an inner peripheral surface of the central hole, a mounting groove on which the forming cover is rotatably placed is formed to be recessed, characterized in that a guide plate is provided that is coupled to the chuck housing and covers and hides an edge of the forming cover, a hydraulic chuck that is easy to form the jaws according to any one of claims 1 to 5.

7. The chuck housing is provided with a scraper for removing foreign matter from an outer portion of the contact portion, characterized in that a hydraulic chuck that is easy to form the jaws according to any one of claims 1 to 5.

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