zipper

Abstract

To provide a chuck built in a cylinder that has a reduced number of components, has a reduced thickness and can be of a lower weight.SOLUTION: According to one aspect of the present invention, a chuck that grips a workpiece at a front of a body is provided. The chuck includes a wedge plunger, a plurality of gripping parts, and first and second cylinder chambers. A single housing space that houses the wedge plunger such that it can move in the axial direction is formed on the inside of the body. The plurality of gripping parts are configured to be capable of gripping or opening a workpiece by moving in a radial direction in response to movement of the wedge plunger. The first and second cylinder chambers are part of the housing space, and are positioned on the front face side and the back face side in the axial direction, respectively. By supplying a working fluid to the first or second cylinder chamber, the wedge plunger is moved in the axial direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a chuck.

Background Art

[0002] In the field of industrial machines and the like, a chuck for gripping a workpiece is used. Such a chuck grips the workpiece with a gripping portion called a jaw so that the central axis of the workpiece coincides with the rotation axis. The opening and closing of the jaw is performed by attaching a cylinder to the lower part of the main shaft of the chuck and supplying a working fluid from the cylinder into the chuck.

[0003] Also, as disclosed in Patent Document 1, a chuck having a built-in cylinder (hereinafter, also referred to as a "chuck with built-in cylinder") is also known. However, in a chuck with a built-in cylinder, the number of parts constituting the chuck increases, and the thickness of the chuck is likely to be larger than that of a general chuck of a type in which the cylinder is attached externally.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of the above circumstances, the present invention aims to provide a chuck with a built-in cylinder that reduces the number of parts, reduces the thickness, and can be lightened.

Means for Solving the Problems

[0006] According to one aspect of the present invention, a chuck for grasping a workpiece at the front of the body is provided. This chuck includes a wedge plunger, a plurality of grasping portions, and first and second cylinder chambers. Inside the body, a single accommodation space is formed for axially movably accommodating the wedge plunger. The plurality of grasping portions are configured to grasp or release the workpiece by moving radially in response to the movement of the wedge plunger. The first and second cylinder chambers are part of the accommodation space and are respectively located on the front side and the rear side in the axial direction. By supplying the working fluid to the first or second cylinder chamber, the wedge plunger is configured to move axially.

[0007] According to such an aspect, in the chuck with built-in cylinder, by integrating predetermined members, the number of parts can be reduced, the thickness can be reduced, and the weight can be reduced.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Various features shown in the following embodiments can be combined with each other.

[0010] FIG. 1 is a perspective view of the chuck 1 according to the present embodiment. FIG. 2 is a front view of the chuck 1 according to the embodiment. FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2. FIG. 4 is a cross-sectional view taken along line B-B of FIG. 2.

[0011] 1. Overall Configuration As shown in FIG. 1, the chuck 1 includes a body 2 and a plurality (three in this embodiment) of gripping portions J attached to the body 2, and grips a workpiece (not shown) on the front surface of the body 2. Each gripping portion J includes a master jaw 3 configured to be insertable into a guide groove 2G in the body 2, a top jaw 4 attached on the master jaw 3 and having a gripping surface 41 for gripping the outer peripheral portion of the workpiece, and a top jaw bolt (not shown) for fixing the top jaw 4 to the master jaw 3. Here, the top jaw 4 has a gripping surface 41 for gripping the outer peripheral portion of the workpiece, but may have a gripping surface for gripping the inner peripheral portion of the workpiece. Also, although two top jaw bolts are inserted into one top jaw 4, the number is not limited to this and depends on the size of the chuck and jaws, etc.

[0012] The body 2 is used with its back side fixed to a machine tool such as a lathe so that its front side is perpendicular to the rotation axis R. When indicating directions in the following description, the front side, back side, axial direction (the direction in which the rotation axis R extends), circumferential direction (the direction around the rotation axis R), radial direction (the direction of its radius centered on the rotation axis R), etc. are used appropriately according to this orientation. The body 2 includes a guide groove 2G provided in the radial direction on its front surface, and the master jaw 3 is accommodated in the guide groove 2G. Also, the body 2 incorporates a wedge plunger 7 for opening and closing the master jaw 3.

[0013] In this embodiment, it is described as having three master jaws 3 and three corresponding top jaws 4, but depending on the shape of the workpiece to be gripped, the gripping method, the size of the chuck 1, the size of the top jaw 4, etc., it may be implemented as having two or four or more master jaws 3 and top jaws 4. In particular, it should be noted that for the chuck 1, the master jaw 3, top jaw 4, and top jaw bolt are arranged at positions equally divided into three when viewed from the front (the upper surface in FIGS. 3 and 4). Since these are the same, only one of them will be described.

[0014] The master jaw 3 has an inverted T shape and is accommodated in a guide groove 2G (see FIG. 1) in the body 2. The master jaw 3 is configured to be openable and closable along the guide groove 2G. The top jaw 4 is fixed to the master jaw 3 by a top jaw bolt. The master jaw 3 and the top jaw 4 may be configured such that, for example, the peaks and valleys of serrations (not shown) formed thereon engage with each other, and their relative positions can be adjusted in pitch units. The direction in which the peaks and valleys are continuous becomes the adjustment direction for adjusting the position of the top jaw 4 with respect to the master jaw 3. After determining the relative positions of the master jaw 3 and the top jaw 4 by the serrations, the relative position of the top jaw 4 with respect to the master jaw 3 can be fixed by screwing the top jaw bolt.

[0015] The master jaw 3 is provided with a wedge portion 32 on the back side opposite to the front side to which the top jaw 4 is attached. As shown in FIG. 3, the wedge portion 32 is configured such that its end face as a contact surface 32a can be pressed by a wedge plunger 7 described later.

[0016] A wedge plunger 7 related to the opening and closing of the master jaw 3 is built into the body 2. As shown in FIG. 3, the wedge plunger 7 has a T groove 71 inside thereof, and the wedge portion 32 engages with the T groove 71. Further, the wedge plunger 7 is configured to be movable in the axial direction by the pressing force of the working fluid.

[0017] The T groove 71 provided inside the wedge plunger 7 is provided so as to approach the rotation axis R from the back side toward the front side. Therefore, when the wedge plunger 7 moves in the axial direction from the front side toward the back side, the master jaw 3 moves radially inward due to the engagement between the T groove 71 in the wedge plunger 7 and the wedge portion 32 in the master jaw 3. On the other hand, when the wedge plunger 7 moves in the axial direction from the back side toward the front side, the master jaw 3 moves radially outward.

[0018] That is, the wedge plunger 7 is arranged to be axially movable inside the body 2, either on the back side or the front side. The three master jaws 3 open and close by moving (radially) along the guide groove 2G in response to the movement of the wedge plunger 7. Thereby, the three top jaws 4 can grasp or release the workpiece.

[0019] The body 2 includes a body main body 21 and a cover 22. The body main body 21 is composed of a front member 211 on the front side and a rear member 212 on the back side. The front member 211 (body main body 21) has an opening 211a that opens to the front. The cover 22 is attached to the front member 211 so as to close the opening 211a.

[0020] Furthermore, the body 2 (chuck 1) includes an adapter 23 that can be connected to a machine tool. By changing the type of the adapter 23 according to the type of the machine tool, the chuck 1 can be connected to different types of machine tools. Thereby, the manufacturing cost of the chuck 1 can be reduced. The chuck 1 is attached to the machine tool while being positioned by a fixing plate 24 attached to the machine tool.

[0021] The chuck 1, in the assembled state, has a single accommodation space 20 formed by the front member 211, the rear member 212, the cover 22, and the adapter 23 inside the body. The wedge plunger 7 is accommodated in this accommodation space 20 while its axial movement is permitted. That is, the wedge plunger 7 moves axially while being guided by the body 2.

[0022] The wedge plunger 7 is disk-shaped and has a through-hole 72 that axially penetrates the central portion in the radial direction thereof. The adapter 23 has a connection portion 231 for connecting to a machine tool and a shaft portion 232 that protrudes from the connection portion 231 toward the front side. And a part of the adapter 23, that is, the shaft portion 232 is inserted into the through-hole 72 of the wedge plunger 7. Thereby, the wedge plunger 7 is configured to be movable (slidable) in the axial direction while being guided not only by the body 2 but also by the shaft portion 232 (adapter 23). For this reason, the axial movement of the wedge plunger 7 is stabilized.

[0023] The cover 22 has a through-hole 221 that axially penetrates the central portion in the radial direction thereof. The front-end portion of the shaft portion 232 is fitted into this through-hole 221. Thereby, the cover 22 and the adapter 23 are connected. Further, the wedge plunger 7 has a recess 73 that is recessed toward the back side on the front-side surface in the axial direction thereof. As shown in FIG. 3, a part of the back side of the cover 22 is inserted into this recess 73 in a liquid-tight manner. The outer peripheral portion on the back side of the cover 22 can function as a guide when the wedge plunger 7 moves (slides) in the axial direction together with the body 2. With such a configuration, the axial movement of the wedge plunger 7 becomes more stable.

[0024] According to the configuration as described above, since the wedge plunger 7 having a configuration in which a plunger and an annular piston are integrated in a conventional cylinder-built-in chuck is used, the number of parts thereof is reduced, the thickness is reduced, and the chuck 1 that has achieved weight reduction can be provided. As a result, a wide machining space for the workpiece can be secured, and the mass of the workpiece to be machined can also be increased.

[0025] Here, as shown in FIG. 4, when the maximum length (maximum height) in the axial direction of the body 2 is H [mm] and the maximum length (maximum width) in the direction orthogonal to the axial direction of the body 2 is L [mm], it is preferable that L / H is 1.7 or more. Specifically, the lower limit value of L / H is, for example, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2, 2.05, 2.1, 2.15, 2.2, 2.25, 2.3, 2.35, 2.4, 2.45, 2.5, 2.55, 2.6, 2.65, 2.7, 2.75, 2.8, 2.85, 2.9, 2.95, 3, 3.05, 3.1, 3.15, 3.2, 3.25, 3.3, 3.35, 3.4, 3.45, 3.5, 3.55, 3.6, 3.65, 3.7, 3.75, 3.8, 3.85, 3.9, 3.95, 4, and it may be within the range between any two of the values exemplified here. If the value of L / H is within such a range, it can be determined that the thickness of the chuck 1 has been sufficiently reduced.

[0026] Further, since the mass of the chuck 1 increases or decreases according to the size of the machine tool to which the chuck 1 is attached, it is not particularly limited.

[0027] 2. Configuration of the cylinder chamber In this section, the cylinder chambers will be described. The chuck 1 has a first cylinder chamber 5 and a second cylinder chamber 6 in a part of the accommodation space 20. The first cylinder chamber 5 is formed as a space surrounded by the body 2 and the wedge plunger 7, and is located on the front side in the axial direction. On the other hand, the second cylinder chamber 6 is formed as a space surrounded by the body 2 and the wedge plunger 7, and is located on the rear side in the axial direction. And the chuck 1 is configured to move the wedge plunger 7 axially by supplying the working fluid to the first cylinder chamber 5 or the second cylinder chamber 6. In this way, by using a part of the accommodation space 20 as a cylinder chamber to which the working fluid is supplied and the remaining part as an empty space to which the working fluid is not supplied, the smooth axial movement of the wedge plunger 7 becomes possible. The supply mechanism of the working fluid to the first cylinder chamber 5 and the second cylinder chamber 6 will be described in detail later. Here, in the configuration shown in FIG. 4, as the working fluid, for example, oil (pressure oil) such as hydraulic oil and oil is preferably used. In the following, the description will continue assuming that the working fluid is oil.

[0028] In the present embodiment, the first cylinder chamber 5 is constituted by a space formed by the cover 22 and the wedge plunger 7. Specifically, the first cylinder chamber 5 is a space surrounded by the recess 73 and a part of the cover 22 inserted into the recess 73. With such a configuration, the thickness of the chuck 1 can be further reduced. On the other hand, the second cylinder chamber 6 is constituted by a space formed by the rear member 212, the adapter 23, and the wedge plunger 7.

[0029] The body 2 has a first passage 25 and a plug (first sealing material) 26. The first passage 25 is formed to penetrate the cover 22 in the axial direction. Thereby, the first passage 25 communicates with the first cylinder chamber 5 and opens to the front of the body 2. The plug 26 is attached to the opening on the front side of the first passage 25 (the side opposite to the first cylinder chamber 5 of the first passage 25).

[0030] The body 2 also has a second passage 27 and a plug (second sealing material) 28. The second passage 27 extends radially outward of the rear member 212, bends midway, and then penetrates the rear member 212 and the front member 211 axially. As a result, the second passage 27 communicates with the second cylinder chamber 6 and opens to the front of the body 2. The plug 28 is attached to the opening on the front side of the second passage 27 (the side opposite to the second cylinder chamber 6 of the second passage 27).

[0031] 3. Configuration of the Actuating Fluid Supply Mechanism In this section, the actuating fluid supply mechanism will be described. As shown in FIG. 4, supply ports 238 and 239 for supplying the actuating fluid are formed on the rear surface of the adapter 23.

[0032] The supply port 238 is connected to the first cylinder chamber 5 via an actuating fluid passage 18 (shown by a solid line in FIG. 4) formed continuously through the adapter 23, the rear member 212, the front member 211, the rear member 212, and the adapter 23. Also, a check valve 8 is provided inside the front member 211, which is midway in the actuating fluid passage 18.

[0033] On the other hand, the supply port 239 is connected to the second cylinder chamber 6 via an actuating fluid passage 19 (shown by a solid line in FIG. 4) formed continuously through the adapter 23, the rear member 212, the front member 211, the rear member 212, and the adapter 23. Also, a check valve 9 is provided inside the front member 211, which is midway in the actuating fluid passage 19.

[0034] The supply port 238 is also connected to the check valve 9 via a check valve passage 11 (shown by a dotted line in FIG. 4) formed continuously through the adapter 23, the rear member 212, and the front member 211.

[0035] On the other hand, the supply port 239 is connected to the check valve 8 via a check valve passage 12 (shown by a dotted line in FIG. 4) formed continuously through the adapter 23, the rear member 212, and the front member 211.

[0036] The check valves 8 and 9 include poppet valves 8P and 9P biased by springs 8S and 9S which are biasing means against valve seats (not shown), and pistons (not shown) moved and operated by the pressure of the working fluid from the working fluid passages 18 and 19. When the pressure difference of the working fluid in the working fluid passages 18 and 19 between the supply side and the supplied side becomes equal to or more than a predetermined value, the poppet valves 8P and 9P move against the biasing force by the springs 8S and 9S to be in an open state, and when it becomes equal to or less than the predetermined value, the poppet valves 8P and 9P are in close contact with the valve seats to be in a closed state.

[0037] Note that by supplying the working fluid through the check valve passages 11 and 12 to operate the piston, it is possible to make it in an open state against the biasing force by the springs 8S and 9S.

[0038] In the present embodiment, the adapter 23 is fixed to the body main body 21 and does not move in the axial direction. For this reason, the working fluid passages 18 and 19 for supplying the working fluid are formed in the adapter 23 in both the first cylinder chamber 5 and the second cylinder chamber 6. Also with such a configuration, it is possible to reduce the thickness of the chuck 1.

[0039] 4. Opening and closing operation of the grasping portion In this section, the opening and closing operation of the grasping portion J will be described. When moving the grasping portion J radially inward (in the radial direction) to the closed side, first, the working fluid is supplied to the supply port 238. The supplied working fluid is transferred via the check valve 8 and through the working fluid passage 18 to fill the first cylinder chamber 5. Thereby, the wedge plunger 7 moves axially backward (downward in FIG. 4). At this time, due to the engagement between the T groove 71 in the wedge plunger 7 and the wedge portion 32 in the master jaw 3, the master jaw 3 moves radially to the closed side. Thereby, the top jaw 4 fixed to the master jaw 3 also moves radially to the closed side.

[0040] Also, at this time, the supply of the working fluid to the supply port 239 is stopped. Since the volume of the second cylinder chamber 6 decreases due to the axial movement of the wedge plunger 7, the working fluid filling the second cylinder chamber 6 is transferred through the working fluid passage 19 and discharged from the supply port 239.

[0041] Note that the working fluid supplied to the supply port 238 is also supplied to the check valve 9 through the check valve passage 11, and when the pressure by the working fluid drops during the use of the chuck 1, the pressure is maintained.

[0042] On the other hand, when moving the grasping portion J radially outward (radial direction to the open side), first, the working fluid is supplied to the supply port 239. The supplied working fluid is transferred through the check valve 9 and the working fluid passage 19 and fills the second cylinder chamber 6. Thereby, the wedge plunger 7 moves axially forward (upper side in FIG. 4). At this time, due to the engagement between the T-groove 71 in the wedge plunger 7 and the wedge portion 32 in the master jaw 3, the master jaw 3 moves radially to the open side. Thereby, the top jaw 4 fixed to the master jaw 3 also moves radially to the open side.

[0043] Also, at this time, the supply of the working fluid to the supply port 238 is stopped. Since the volume of the first cylinder chamber 5 decreases due to the axial movement of the wedge plunger 7, the working fluid filling the first cylinder chamber 5 is transferred through the working fluid passage 18 and discharged from the supply port 239.

[0044] Note that the working fluid supplied to the supply port 239 is also supplied to the check valve 8 through the check valve passage 12, and when the pressure by the working fluid drops during the use of the chuck 1, the pressure is maintained.

[0045] 5. Air bleeding operation In this section, the air bleeding operation will be described. First, with the front of the chuck 1 vertically upward, the opening and closing of the grasping portion J is performed at a low pressure as described above.

[0046] When the gripping part J is opened, the plug 26 is slightly loosened, and when the gripping part J is closed, the plug 28 is slightly loosened. By repeating this operation, the air stored in the first cylinder chamber 5, the second cylinder chamber 6, the working fluid passages 18, 19, the check valve passages 11, 12, the first passage 25, and the second passage 27 can be discharged.

[0047] Since the attachment work of the chuck 1 to the machine tool is usually performed with the front of the chuck 1 facing vertically upward (the origin position), if the plugs 26, 28 are configured to be mounted on the front side of the chuck 1, the workability of the plugs 26, 28 can be improved.

[0048] 6. Others As described above, according to the present embodiment, in the chuck with an internal cylinder, it is possible to reduce the number of parts, reduce the thickness, and realize the chuck 1 that can be lightened. As a result, a wide machining space for the workpiece can be secured, and the mass of the workpiece to be machined can also be increased.

[0049] In addition, the chuck 1 according to the present embodiment can also be implemented in the following manner.

[0050] In the foregoing embodiment, the working fluid has been described as being oil (hydraulic oil), but instead, air (compressed air) can be used, and other liquids or gases can also be used.

[0051] Regarding the adapter 23, only one of the working fluid passages 18, 19 may be formed in the adapter 23.

[0052] Furthermore, it may be provided in each of the aspects described below. In the chuck, the body includes a body main body and a cover. The body main body has an opening that opens to the front surface. The cover is attached to the body main body so as to close the opening. The wedge plunger has a recess that is recessed toward the back surface on the front surface side in the axial direction thereof. A part of the cover is inserted into the recess. The first cylinder chamber is a space surrounded by the recess and a part of the cover inserted into the recess. In the chuck, the body has a first passage, a first sealing material, a second passage, and a second sealing material. The first passage communicates with the first cylinder chamber and opens to the front surface. The first sealing material is attached to the side of the first passage opposite to the first cylinder chamber. The second passage communicates with the second cylinder chamber and opens to the front surface. The second sealing material is attached to the side of the second passage opposite to the second cylinder chamber. In the chuck, the body further includes an adapter that can be connected to a machine tool. A part of the adapter axially penetrates the central portion in the radial direction of the wedge plunger. The wedge plunger is configured to be movable in the axial direction. An operating fluid passage for supplying the operating fluid is formed in the adapter in at least one of the first cylinder chamber and the second cylinder chamber. Of course, this is not the limit.

[0053] Finally, although various embodiments of the present invention have been described, these are presented as examples and are not intended to limit the scope of the invention. The novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The embodiments and their modifications are included in the scope and gist of the invention and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0054] 1: Chuck 11: Check Valve Passage 12: Check valve passage 18: Actuating fluid passage 19: Actuating fluid passage 2: Body 20: Accommodating space 21: Body main body 211a: Opening 22: Cover 23: Adapter 25: First passage 26: Plug 27: Second passage 28: Plug 3: Master jaw 4: Top jaw 5: First cylinder chamber 6: Second cylinder chamber 7: Wedge plunger 73: Recess R: Rotation axis

Claims

1. A chuck for gripping a workpiece at the front of a body, comprising: a wedge plunger, a plurality of gripping portions, and first and second cylinder chambers; a single accommodation space is formed inside the body for axially movably accommodating the wedge plunger; the plurality of gripping portions are configured to grip or release the workpiece by moving radially in response to the movement of the wedge plunger; the first and second cylinder chambers are part of the accommodation space and are respectively located on the front side and the rear side in the axial direction; by supplying a working fluid to the first or second cylinder chamber, the wedge plunger is configured to move axially; the body includes a body main body and a cover; the body main body has an opening that opens to the front of the body; the cover is attached to the body main body so as to close the opening; the wedge plunger has a recess that is recessed on the rear side at the front end surface in the axial direction; a part of the cover is inserted into the recess; the first cylinder chamber is a space surrounded by the recess and a part of the cover inserted into the recess, the chuck.

2. A chuck for gripping a workpiece at the front of a body, comprising: a wedge plunger, a plurality of gripping portions, and first and second cylinder chambers; a single accommodation space is formed inside the body for axially movably accommodating the wedge plunger; the plurality of gripping portions are configured to grip or release the workpiece by moving radially in response to the movement of the wedge plunger; the first and second cylinder chambers are part of the accommodation space and are respectively located on the front side and the rear side in the axial direction; by supplying a working fluid to the first or second cylinder chamber, the wedge plunger is configured to move axially; the body has a first passage, a first sealing material, a second passage, and a second sealing material; the first passage communicates with the first cylinder chamber and opens to the front; the first sealing material is attached to the side of the first passage opposite to the first cylinder chamber; the second passage communicates with the second cylinder chamber and opens to the front; the second sealing material is attached to the side of the second passage opposite to the second cylinder chamber, the chuck.

3. In the chuck according to Claim 1 or Claim 2, The body further includes an adapter connectable to a machine tool, a part of the adapter axially penetrates a radially central portion of the wedge plunger, the wedge plunger is configured to be movable axially, a chuck in which an operating fluid passage for supplying the operating fluid is formed in the adapter in at least one of the first cylinder chamber and the second cylinder chamber.

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