Workpiece holding chuck and workpiece processing device

Abstract

To provide a work-piece holding chuck that can increase amounts of expansion and contraction thereof while reducing force for expansion and contraction, and a work-piece processing device.SOLUTION: A work-piece holding chuck 100 comprises a chuck body 101. The chuck body 101 is formed in a cylindrical shape, in which a chuck part 102 is formed on an outer periphery part and thick parts 103 and thin parts 105 are formed on an inner periphery part. The chuck part 102 is constituted of circular-curved surfaces. The six thick parts 103 are formed at equal intervals along a circumferential direction. The six thin parts 105 are formed at an outermost periphery portion of the chuck main body 101 to be thinner than the thick parts 103 and are formed at equal intervals along the circumferential direction. Further, small thick parts 110 are formed at center portions in the circumferential direction of the thin parts 105. The small thick parts 110 are formed to protrude in a semicircular shape from surfaces of the thin parts 105 toward inside in a radial direction of the chuck main body 101.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a work holding chuck that detachably holds a workpiece to be machined.

Background Art

[0002] Conventionally, there has been a work holding chuck that detachably holds a workpiece to be machined. For example, Patent Document 1 below discloses a clamping device provided with a positioning pin in which a cylindrical expansion / contraction part inserted into a reference hole of a work expands and contracts in the radial direction by a center pin inserted into this expansion / contraction part. In this case, the positioning pin formed in a cylindrical shape is configured such that the outer diameter expands and contracts by forming a groove inside the cylindrical body.

Prior Art Document

Patent Document

[0003]

Patent Document 1

[0004] However, in the positioning pin described in Patent Document 1, since the rigidity of the portion where the groove is formed is reduced, it is difficult to form a deep groove or a wide groove, and there are problems that a large force is required to expand and contract the expansion / contraction part and the amount of expansion and contraction is small.

Summary of the Invention

[0005] The present invention has been made to address the above problems, and an object thereof is to provide a work holding chuck and a work processing apparatus that can increase the amount of expansion and contraction while reducing the force for expansion and contraction.

[0006] To achieve the above objective, the present invention features a workpiece holding chuck for detachably holding a cylindrical workpiece, comprising: a cylindrical chuck body; a chuck portion formed on the outer circumference of the chuck body for pressing against the inner circumference of the workpiece; at least three or more thickened portions formed along the circumferential direction on the inner circumference of the chuck body and protruding radially inward from the chuck body; and at least three or more formed thickened portions The radially inner surface in Each inner surface is provided with a tapered portion formed in a tapered shape along the axial direction of the chuck body, where the inner diameter changes continuously, and a thin-walled portion formed between two adjacent thick portions in the circumferential direction, where the thin-walled portion is thinner than the thick portion, and the thin-walled portion has a small thickness that protrudes radially inward from the chuck body with an amount of protrusion less than or equal to that of the thick portion.

[0007] To achieve the above objective, the present invention features a workpiece holding chuck for detachably holding a cylindrical workpiece, comprising: a cylindrical chuck body; a chuck portion formed on the inner circumference of the chuck body for pressing against the outer surface of the workpiece; at least three or more thickened portions formed on the outer circumference of the chuck body along the circumferential direction and protruding radially outward from the chuck body; and at least three or more formed thickened portions The radially outer surface in Each outer surface is provided with a tapered portion formed in a tapered shape along the axial direction of the chuck body, where the outer diameter changes continuously, and a thin-walled portion formed between two adjacent thick portions in the circumferential direction, where the thin-walled portion is thinner than the thick portion, and the thin-walled portion has a small thickness that protrudes radially outward from the chuck body with an amount of protrusion less than or equal to that of the thick portion.

[0008] According to the features of the present invention configured in this way, the workpiece holding chuck has a thin-walled portion between the tapered thick-walled portion and the thick-walled portion, and a small-thick-walled portion with an overhang less than or equal to the overhang of the thick-walled portion is formed in the thin-walled portion. This makes the thin-walled portion more flexible while suppressing a decrease in rigidity, thereby increasing the amount of expansion and contraction while reducing the force required for expansion and contraction.

[0009] Another feature of the present invention is that, in the workpiece holding chuck, the thin-walled portion is raised relative to the thin-walled portion via a curved surface.

[0010] According to another feature of the present invention configured in this way, the workpiece holding chuck has a small-walled portion that rises relative to the thin-walled portion via a curved surface, which makes it possible to suppress damage between the thin-walled portion and the small-walled portion when the thin-walled portion is deformed and to facilitate deformation.

[0011] Another feature of the present invention is that, in the workpiece holding chuck, the thin-walled portion is formed in the central portion between two adjacent thick-walled portions.

[0012] According to other features of the present invention configured in this way, the workpiece holding chuck has a small thickness portion formed in the central part between two adjacent thickness portions, which suppresses irregular or uneven deformation of the thin portion and allows for uniform deformation, thereby enabling accurate holding of the workpiece.

[0013] Another feature of the present invention is that, in the workpiece holding chuck, the protrusion amount of the thin-walled portion is 1 / 10 or less of the protrusion amount of the thick-walled portion.

[0014] According to other features of the present invention configured in this way, in a workpiece holding chuck, the protrusion amount of the thin-walled portion is formed to be 1 / 10 or less of the protrusion amount of the thick-walled portion, making it easier to position adjacent thick-walled portions close together, thereby increasing the area of ​​the tapered portion in the thick-walled portion and allowing the chuck body to be expanded and contracted with high precision.

[0015] Another feature of the present invention is that, in the workpiece holding chuck, the thin-walled portion is provided with a recessed relief portion on the surface opposite to the thick-walled portion.

[0016] According to other features of the present invention configured in this way, the workpiece holding chuck has a recessed relief portion formed on the side of the thin-walled portion opposite to the thick-walled portion. Therefore, the amount of expansion and contraction of the entire chuck body can be increased by thinning the thin-walled portion due to the relief portion and by expanding or contracting the groove width of the relief portion.

[0017] Another feature of the present invention is that, in the workpiece holding chuck, the thick-walled portion and the thin-walled portion are connected by a curved surface.

[0018] According to other features of the present invention configured in this way, since the thick and thin parts of the workpiece holding chuck are connected by a curved surface, damage between the thin and thick parts during deformation of the thin part can be suppressed, making deformation easier.

[0019] Another feature of the present invention is that, in the workpiece holding chuck, the chuck body is formed in a C-shape when viewed from the coaxial direction by a notch that extends through in the axial direction.

[0020] According to another feature of the present invention configured in this way, the workpiece holding chuck is formed in a C-shape when viewed from the coaxial direction by a notch that extends through the axial direction of the chuck body, making it easier to expand and contract the chuck body and increasing the amount of expansion and contraction.

[0021] Furthermore, the present invention can be implemented not only as an invention of a workpiece holding chuck, but also as an invention of a workpiece processing apparatus capable of holding this workpiece holding chuck.

[0022] Specifically, the workpiece processing apparatus preferably includes a workpiece holder that holds the workpiece holding chuck according to any one of claims 1 to 8, a device-side tapered portion formed in a tapered shape that fits into the tapered portion of the workpiece holding chuck, and chuck displacement means for relatively displacing the workpiece holding chuck with respect to the device-side tapered portion. According to this, the workpiece processing apparatus can expect the same operational effects as the above-described workpiece holding chuck.

Brief Description of the Drawings

[0023] [Figure 1] (A) and (B) show the schematic configuration of the workpiece holding chuck according to the first embodiment of the present invention. (A) is a plan view of the workpiece holding chuck, and (B) is a longitudinal sectional view of the workpiece holding chuck as viewed from the B-B line of (A). [Figure 2] It is a partially enlarged view of the workpiece holding chuck obtained by enlarging the portion surrounded by the broken-line circle 2 in FIG. 1. [Figure 3] It is a sectional view showing a state where the workpiece holding chuck shown in FIG. 1 is attached to the workpiece holder. [Figure 4] It is a partially enlarged view showing a state where the outer diameter of the workpiece holding chuck shown in FIG. 2 is enlarged. [Figure 5] (A) and (B) show the schematic configuration of the workpiece holding chuck according to the second embodiment of the present invention. (A) is a plan view of the workpiece holding chuck, and (B) is a longitudinal sectional view of the workpiece holding chuck as viewed from the B-B line of (A). [Figure 6] It is a sectional view showing a state where the workpiece holding chuck shown in FIG. 5 is attached to the workpiece holder. [Figure 7] It is a partially enlarged view of the workpiece holding chuck showing a modified example of the workpiece holding chuck according to the first embodiment. [Figure 8] It is a partially enlarged view of the workpiece holding chuck showing another modified example of the workpiece holding chuck according to the first embodiment.

Modes for Carrying Out the Invention

[0024] <First Embodiment> Hereinafter, an embodiment of the workpiece holding chuck according to the first embodiment of the present invention will be described with reference to the drawings. Figures 1(A) and 1(B) show an outline of the configuration of the workpiece holding chuck 100 according to the first embodiment of the present invention, where (A) is a plan view of the workpiece holding chuck 100 and (B) is a longitudinal cross-sectional view of the workpiece holding chuck 100 as seen from line BB in (A).

[0025] This workpiece holding chuck 100 is a device that is attached to a rotating spindle in a machine tool (not shown), such as a gear cutting machine, lathe, or grinding machine, to detachably hold a cylindrical workpiece WK. The workpiece holding chuck 100 can also be used to center and position the cylindrical workpiece WK on a work table in a machine tool (not shown), such as a milling machine or machining center.

[0026] The workpiece holding chuck 100 includes a chuck body 101. The chuck body 101 is composed of a chuck portion 102, a thick portion 103, and a thin portion 105, and is constructed by forming a metal material such as steel into a cylindrical shape. The chuck portion 102 is formed on the outer circumference of the chuck body 101, while the thick portion 103 and thin portion 105 are formed on the inner circumference. The axial length of the chuck body 101 is formed to be long enough to stably hold the workpiece WK during machining.

[0027] The chuck portion 102 is the part that holds the cylindrical workpiece WK by pressing its inner circumferential surface against it, and its cross-sectional shape is a curved surface with a circular shape (hereinafter sometimes referred to as a "circular curved surface"). The outer diameter of this chuck portion 102 is slightly smaller than the inner diameter of the cylindrical workpiece WK, that is, its surface is smoothly formed with a clearance tolerance.

[0028] The thickened portion 103 is the part that ensures the rigidity of the chuck body 101 and where the tapered portion 104 is formed. It extends axially along the inner circumference of the chuck body 101 and is formed intermittently along the circumferential direction. In this embodiment, the thickened portion 103 is formed along the entire axial length of the chuck body 101 and is formed in six equal intervals along the circumferential direction.

[0029] The tapered portion 104 is the part against which the chuck operating shaft 201, described later, is pressed. It is formed in a tapered shape where the inner diameter continuously decreases from one end (upper in Figure 1(B)) to the other end (lower in Figure 1(B)) of the chuck body 101. In this case, the taper angle of the tapered portion 104 corresponds to the taper angle of the device-side tapered portion 202 so as to be in close contact with the device-side tapered portion 202 of the chuck operating shaft 201. The axis of this tapered portion 104 coincides with the axis of the cylindrical body that constitutes the chuck portion 102.

[0030] As shown in Figure 2, the thin-walled portion 105 is a part that expands or contracts the outer diameter of the chuck body 101, and is formed intermittently along the circumferential direction, extending axially on the inner circumference of the chuck body 101. In this case, the thin-walled portion 105 is formed between each of the intermittently formed thick-walled portions 103 along the circumferential direction. In this embodiment, the thin-walled portion 105 is formed along the entire axial length of the chuck body 101, and six of them are formed at equal intervals along the circumferential direction.

[0031] Furthermore, the thin-walled portion 105 is formed on the outermost periphery of the chuck body 101 and is thinner than the thick-walled portion 103. In this case, the thinner the thickness of the thin-walled portion 105, the easier it is to deform but the lower its rigidity. Therefore, a thickness of 0.5% or more and 6% or less relative to the outer diameter of the chuck body 101 is preferable. More specifically, the thickness of the thin-walled portion 105 is preferably 0.1 mm or more and 5 mm or less when the outer diameter of the chuck body 101 is 20 mm or more and 50 mm or less, but more preferably 0.1 mm or more and 1 mm or less.

[0032] Furthermore, the forming angle α of the thin-walled portion 105 with respect to the center O of the chuck body 101 may be a different angle or the same angle as the forming angle β of the thick-walled portion 103 with respect to the center O of the chuck body 101. Therefore, the radially outer circumferential length Lα of the thin-walled portion 105 may be different from or the same as the radially outer circumferential length Lβ of the thick-walled portion 103. In this case, the radially outer circumferential length Lα of the thin-walled portion 105 is the length of the straight line or arc connecting both ends (joint points with the boundary portion 106) of the thin-walled portion 105. Similarly, the radially outer circumferential length Lβ of the thick-walled portion 103 is the length of the straight line or arc connecting both ends (joint points with the boundary portion 106) of the thick-walled portion 103.

[0033] Furthermore, the thin-walled portion 105 is connected to the thick-walled portion 103 at both circumferential ends via a curved boundary portion 106. A small-thick portion 110 is formed in the circumferential central part of the thin-walled portion 105.

[0034] As shown in Figure 2, the small-walled portion 110 is a part that increases the rigidity of the thin-walled portion 105, and is formed by protruding from the surface of the thin-walled portion 105 toward the radially inward side of the chuck body 101 (towards the center O in this embodiment). In this case, the small-walled portion 110 is formed by extending continuously or intermittently along the axial direction of the chuck body 101. In this embodiment, the small-walled portion 110 is formed by a projection with a semicircular cross-sectional shape that extends continuously along the axial direction of the chuck body 101.

[0035] The amount of protrusion (height) T1 of the small-walled portion 110 from the thin-walled portion 105 is set within a range where the thick-walled portion 103 does not reach the portion that holds the chuck operating shaft 201, i.e., the tapered portion 104. In this case, the amount of protrusion T1 of the small-walled portion 110 is preferably 1 / 10 or less of the height T2 of the thick-walled portion 103. More specifically, when the outer diameter of the chuck body 101 is 20 mm or more and 50 mm or less, the amount of protrusion T1 of the small-walled portion 110 is preferably 0.1 mm or more and 10 mm or less, but more preferably 0.1 mm or more and 5 mm or less. Note that by setting the amount of protrusion T1 of the small-walled portion 110 to be greater than the thickness of the thin-walled portion 105, the rigidity of the thin-walled portion 105 can be made extremely high.

[0036] Furthermore, the forming angle γ of the thin-walled portion 110 with respect to the center O of the chuck body 101 is formed at an angle less than the forming angle α of the thin-walled portion 105. In this case, the forming angle γ of the thin-walled portion 110 is preferably 1 / 2 or less of the forming angle α of the thin-walled portion 105, and more preferably 1 / 5 or less. In addition, both ends of the thin-walled portion 110 in the circumferential direction are connected to the thin-walled portion 105 via a curved boundary portion 111. This thin-walled portion 110 is formed with the same shape for each of the six thin-walled portions 105.

[0037] The workpiece holding chuck 100 configured in this way is manufactured by machining, such as cutting and electrical discharge machining. In this case, it is preferable to improve the hardness of the workpiece holding chuck 100 by heat treatment.

[0038] (Configuration of workpiece holder 200) The workpiece holding chuck 100 configured as described above is attached to a machine tool that processes the workpiece WK via a workpiece holder 200. Here, the machine tool is a processing device that performs cutting, plastic deformation, or removal processing on the workpiece WK using a cutting tool S such as a turning tool, cutter, drill, end mill, punch, grinding wheel, or laser.

[0039] As shown in Figure 3, the workpiece holder 200 is a device for holding the workpiece WK by operating the workpiece holding chuck 100, and mainly consists of a chuck operating shaft 201, a pressing collar 204, and an operator 206.

[0040] The chuck operating shaft 201 is a component that supports the workpiece holding chuck 100 and holds the workpiece WK via the workpiece holding chuck 100, and is constructed by forming a cylindrical shape from a metal material such as steel. The chuck operating shaft 201 is mainly constructed by integrally forming the device-side tapered portion 202, collar guide portion 203, male screw portion 205, spring holding portion 207, flange portion 209, and spindle connection portion 210.

[0041] The device-side tapered portion 202 is a part that expands and contracts the outer diameter of the workpiece holding chuck 100 while holding the workpiece holding chuck 100 in a slidable state, and is formed in the axial center of the chuck operating shaft 201. More specifically, the device-side tapered portion 202 extends from the spring holding portion 207 towards the collar guide portion 203. Outer diameter The tapered shape is formed in which the diameter decreases continuously. In this case, the taper angle of the device-side tapered portion 202 corresponds to the taper angle of the tapered portion 104 formed on the inner circumference of the workpiece holding chuck 100 so as to be in close contact with the tapered portion 104 formed on the inner circumference of the said tapered portion 104. In addition, the axis of the device-side tapered portion 202 coincides with the axis of the cylindrical body that constitutes the chuck operating shaft 201.

[0042] The collar guide portion 203 is a part that holds the pressing collar 204 so that it can reciprocate and slide in the axial direction of the chuck operating shaft 201, and is formed in a cylindrical shape adjacent to the device-side tapered portion 202. The pressing collar 204 is a part that pushes the workpiece holding chuck 100, which fits into the device-side tapered portion 202, toward the axial rear side (left side in the figure) of the device-side tapered portion 202, and is constructed by forming a metal material such as steel into a cylindrical shape.

[0043] The male threaded portion 205 is the part into which the operator 206 is screw-fitted, and is formed in a cylindrical shape at one end (right side in the figure) of the chuck operating shaft 201, adjacent to the collar guide portion 203. The operator 206 is a component for pushing the pressing collar 204 toward the device-side tapered portion 202, and is constructed by forming a female thread on the inner circumferential surface of a cylindrical body made of a metal material such as steel, which engages with the male threaded portion 205.

[0044] The spring holding portion 207 is a part that holds the spring 208 in an expandable and contractible state, and is formed in a cylindrical shape adjacent to the device-side tapered portion 202 on the opposite side from the collar guide portion 203. The spring 208 is a component that provides elastic force to the workpiece holding chuck 100 which slides on the device-side tapered portion 202, and is made of a coil spring made of a metal material such as steel. One end of this spring 208 (right side in the figure) presses against the workpiece holding chuck 100 via a ring-shaped spacer 208a, while the other end (left side in the figure) presses against the flange portion 209.

[0045] The flange portion 209 is the part against which one end (left side in the figure) of the cylindrical workpiece WK abuts, thereby defining its axial position. This flange portion 209 is formed as a disc-shaped projection in the radial direction of the chuck operating shaft 201, adjacent to the spring holding portion 207 on the opposite side from the device-side tapered portion 202.

[0046] The spindle connection portion 210 is the part that connects the chuck operating shaft 201 to the spindle (not shown) of the machine tool, and is formed in a cylindrical shape at one end (left side in the figure) of the chuck operating shaft 201. When this spindle connection portion 210 is connected to the spindle of the machine tool, the entire workpiece holder 200 rotates around its axis.

[0047] (Operation of workpiece holding chuck 100) Next, the operation of the workpiece holding chuck 100 configured as described above will be explained. This workpiece holding chuck 100 is attached to a machine tool via the workpiece holder 200 described above, and machining is performed.

[0048] First, the operator prepares the workpiece holding chuck 100 and attaches it to the workpiece holder 200. Specifically, the operator inserts the workpiece holding chuck 100 from the male threaded portion 205 side of the workpiece holder 200 and brings the tapered portion 104 into close contact with the tapered portion 202 on the device side. In this case, the tip of the workpiece holding chuck 100 (left end in the figure) contacts the spring 208 via the spacer 208a.

[0049] Next, the operator inserts the pressing collar 204 from the male threaded portion 205 side of the workpiece holder 200, positions it on the collar guide portion 203, and abuts it against the rear end (right end in the figure) of the workpiece holding chuck 100. Next, the operator screws the operator 206 into the male threaded portion 205 and tightens it lightly. As a result, the workpiece holding chuck 100 is pushed towards the spring 208 side by the pressing collar 204, pressing the tapered portion 104 against the device-side tapered portion 202. In this case, the outer diameter of the workpiece holding chuck 100 does not change because the tightening force of the operator 206 is small. This allows the operator to attach the workpiece holding chuck 100 to the workpiece holder 200.

[0050] Next, the operator attaches the workpiece WK to the workpiece holder 200. In this case, the workpiece WK is formed in a cylindrical shape and has a holding portion H on its inner circumference with an inner diameter slightly larger than the outer diameter of the chuck portion 102 of the workpiece holding chuck 100. The operator inserts the workpiece WK from the male thread portion 205 side so that the tip (left end in the figure) abuts against the flange portion 209. This positions the workpiece WK so that the holding portion H is located on the chuck portion 102 of the workpiece holding chuck 100.

[0051] Next, the operator holds the workpiece WK with the workpiece holding chuck 100. Specifically, the operator further screws the operator 206 into the male threaded portion 205 and tightens it. As a result, the workpiece holding chuck 100 is pushed by the pressing collar 204 against the elastic force of the spring 208, causing the tapered portion 104 to be strongly pressed against the device-side tapered portion 202. In other words, the male threaded portion 205 and the operator 206 correspond to the chuck displacement means in the present invention.

[0052] In this case, the thicker portion 103 of the workpiece holding chuck 100 is pushed radially outward by the tapered portion 202 on the device side. As a result, the thin-walled portion 105 of the workpiece holding chuck 100 elastically deforms from a curved surface state to a flat state, as shown in Figure 4. In this case, since a small thicker portion 110 is formed on the thin-walled portion 105 of the workpiece holding chuck 100, damage during elastic deformation is suppressed. As a result, the outer diameter of the chuck portion 102 of the workpiece holding chuck 100 expands, and the workpiece WK can be held by pressing the held portion H of the workpiece WK radially outward. In other words, the operator can hold the workpiece WK on the workpiece holder 200 using the workpiece holding chuck 100.

[0053] The operator can then perform machining operations such as cutting or grinding on the workpiece WK by operating a machine tool. Since this machining operation on the workpiece WK is not directly related to the present invention, its explanation will be omitted.

[0054] Next, when the workpiece WK has been processed, the operator removes the workpiece WK from the workpiece holder 200. Specifically, the operator loosens the tightening force of the operator 206 on the male screw portion 205. As a result, the workpiece holding chuck 100 is displaced toward the operator 206 due to the elastic force of the spring 208. In this case, the pressing force of the workpiece holding chuck 100 toward the thick portion 103 by the tapered portion 202 on the device side is reduced.

[0055] As a result, the shape of the workpiece holding chuck 100 returns from a flat state to a curved state at the thin-walled portion 105. In this case, since the thin-walled portion 105 has a small-thickness portion 110 formed on it, damage during elastic deformation is suppressed. As a result, the outer diameter of the chuck portion 102 of the workpiece holding chuck 100 decreases, and the radially outward pressing of the workpiece WK against the held portion H is weakened, releasing the workpiece WK from being held. Therefore, the operator can remove the workpiece WK from the workpiece holder 200 by pulling it out of the workpiece holding chuck 100 and the workpiece holder 200.

[0056] Furthermore, the operator can also remove the workpiece holding chuck 100 from the workpiece holder 200. Specifically, the operator further loosens the tightening force of the operator 206 on the male screw portion 205 and removes the operator 206 from the male screw portion 205. Then, after removing the pressing collar 204 from the chuck operating shaft 201, the operator can remove the workpiece holding chuck 100 from the workpiece holder 200 by removing the workpiece holding chuck 100 from the chuck operating shaft 201.

[0057] As can be understood from the above description of operation, according to the first embodiment, the workpiece holding chuck 100 has a thick section 103 having a tapered section 104 and a thin section 105 between the thick section 103, and a small thick section 110 with an overhang amount less than or equal to the overhang amount of the thick section 103 is formed in this thin section 105. Therefore, it is possible to increase the amount of expansion and contraction while suppressing the decrease in rigidity of the thin section 105 and making it easier to deform, thereby reducing the force required for expansion and contraction.

[0058] <Second Embodiment> Next, the workpiece holding chuck 300 according to the second embodiment of the present invention will be described with reference to Figures 5(A), (B), and 6, respectively. In the first embodiment described above, the workpiece holding chuck 100 was configured to hold the inner circumference of a cylindrical workpiece WK. However, the workpiece holding chuck 300 in this second embodiment differs from the first embodiment in that it holds the outer circumference of a cylindrical or rod-shaped workpiece WK. Therefore, in this second embodiment, the explanation will focus on the parts that differ from the first embodiment, and the explanation of parts common to both embodiments and corresponding parts will be omitted as appropriate.

[0059] This workpiece holding chuck 300 comprises a chuck body 301, a chuck section 302, a thick section 303, a tapered section 304, a thin section 305, a boundary section 306, and a small thick section 310.

[0060] The chuck body 301 is a component corresponding to the chuck body 101 in the first embodiment described above, and is constructed by forming a metal material such as steel into a cylindrical shape. The chuck body 301 has a chuck portion 302 formed on its inner circumference, and a thick portion 303 and a thin portion 305 formed on its outer circumference, respectively.

[0061] The chuck portion 302 corresponds to the chuck portion 102 in the first embodiment described above, but unlike the chuck portion 102, it is cylindrical in shape to hold the workpiece WK by pressing against the outer circumferential surface of the workpiece WK.

[0062] The thickened portion 303 corresponds to the thickened portion 103 in the first embodiment described above, but unlike the thickened portion 103, it extends axially on the outer circumference of the chuck body 301 and is formed intermittently along the circumferential direction. In this embodiment, the thickened portion 303 is formed along the entire axial length of the chuck body 301 and is formed in six equal intervals along the circumferential direction.

[0063] The tapered portion 304 corresponds to the tapered portion 104 in the first embodiment described above, but unlike the tapered portion 104, it is formed in a tapered shape in which the outer diameter continuously decreases from one end (upper side in Figure 4(B)) to the other end (lower side in Figure 4(B)) of the chuck body 301.

[0064] The thin-walled portion 305 corresponds to the thin-walled portion 105 in the first embodiment described above, but unlike the thin-walled portion 105, it extends axially on the outer circumference of the chuck body 301 and is formed intermittently along the circumferential direction. In this case, the thin-walled portion 305 is formed between each of the thick-walled portions 303 that are formed intermittently along the circumferential direction. In this embodiment, the thin-walled portion 305 is formed along the entire axial length of the chuck body 301 and is formed in groups of six at equal intervals along the circumferential direction.

[0065] Furthermore, the thin-walled portion 305 is formed to be thinner than the thick-walled portion 303 at the innermost circumference of the chuck body 101. A small-thick-walled portion 310 is formed in the circumferential center of the thin-walled portion 305. In this case, both sides of the small-thick-walled portion 310 on the radially outer surface of the chuck body 301 are formed as curved surfaces, and both ends in the circumferential direction are connected to the thick-walled portion 303 via curved-surface boundary portions 306.

[0066] The connecting portion 307 is the part that connects the chuck body 301 to the chuck retracting tool 420, which will be described later. Specifically, the connecting portion 307 is made up of a female screw that opens into an opening on the inner circumference of the chuck body 301, on the side opposite to the chuck portion 102.

[0067] The small-walled portion 310 corresponds to the small-walled portion 110 in the first embodiment described above, but unlike the small-walled portion 110, it is formed by protruding from the surface of the thin-walled portion 305 toward the radially outward direction of the chuck body 301 (radially toward the center O of the chuck body 301 in this embodiment). In this embodiment, the small-walled portion 310 is formed by a rectangular projection with rounded corners that extends continuously along the axial direction of the chuck body 301. Furthermore, both ends of the small-walled portion 310 in the circumferential direction are connected to the thin-walled portion 305 via a circularly curved boundary portion 311.

[0068] (Configuration of workpiece holder 400) The workpiece holding chuck 300 configured as described above is attached to a machine tool (not shown) that processes the workpiece WK via a workpiece holder 400. As shown in Figure 6, the workpiece holder 400 is a device for operating the workpiece holding chuck 300 to hold the workpiece WK, similar to the first embodiment described above, and is mainly composed of a chuck operating shaft 401 and a chuck retracting tool 420.

[0069] The chuck operating shaft 401 is a component that supports the workpiece holding chuck 300 and holds the workpiece WK via the workpiece holding chuck 300, and is constructed by forming a cylindrical shape from a metal material such as steel. The chuck operating shaft 401 is mainly constructed by integrally forming the device-side tapered portion 402 and the spindle connection portion 410.

[0070] The device-side tapered portion 402 is a part that expands and contracts the inner diameter of the workpiece holding chuck 300 while holding the workpiece holding chuck 300 in a slidable state, and is formed on the inner circumference of the chuck operating shaft 401. More specifically, the device-side tapered portion 402 is formed in a tapered shape in which the inner diameter continuously decreases from one end (right side in the figure) to the other end (left side in the figure). In this case, the taper angle of the device-side tapered portion 402 corresponds to the taper angle of the tapered portion 304 formed on the outer surface of the workpiece holding chuck 300 so as to be in close contact with the tapered portion 304 formed on the outer surface of the workpiece holding chuck 300. Furthermore, the axis of the device-side tapered portion 402 coincides with the axis of the cylindrical body that constitutes the chuck operating shaft 401.

[0071] The spindle connection portion 410 is the part that connects the chuck operating shaft 401 to the spindle (not shown) of the machine tool, and is formed as a radially disc-shaped projection from one end (left side in the figure) of the chuck operating shaft 401. When this spindle connection portion 410 is connected to the spindle of the machine tool, the entire workpiece holder 400 is driven to rotate around its axis.

[0072] The chuck retractor 420 is a component used to press or separate the tapered portion 304 of the workpiece holding chuck 300 from the tapered portion 402 on the device side, and is constructed by forming a metal material such as steel into an axial shape. The chuck retractor 420 has a male threaded portion 421 formed at its tip that is screwed into the connecting portion 307 of the workpiece holding chuck 300, and a fixing wall 422 is formed at the end of this male threaded portion 421.

[0073] The fixed wall 422 is a part that connects the chuck retractor 420 and the chuck body 301 by abutting against the chuck body 301 which is screwed into the male threaded portion 421, and is formed to protrude radially in a disc shape. This chuck retractor 420 is attached to the machine tool so as to reciprocate in the axial direction. Furthermore, this chuck retractor 420 corresponds to the chuck displacement means according to the present invention.

[0074] (Operation of workpiece holding chuck 300) Next, the operation of the workpiece holding chuck 300 configured as described above will be explained. This workpiece holding chuck 300 is attached to a machine tool via the workpiece holder 400 described above, and machining is performed.

[0075] First, the worker prepares the workpiece holding chuck 300 and attaches it to the workpiece holder 400. Specifically, the worker inserts the workpiece holding chuck 300 into the chuck operating shaft 401, screws the connecting part 307 into the male threaded part 421 of the chuck retractor 420, and presses it against the fixing wall 422 to secure it. This allows the worker to attach the workpiece holding chuck 300 to the machine tool via the workpiece holder 400.

[0076] Next, the operator attaches the workpiece WK to the workpiece holder 400. In this case, the workpiece WK may be formed in a cylindrical shape or a solid rod shape, but a holding portion H is formed on its outer circumference, with an outer diameter slightly smaller than the inner diameter of the chuck portion 302 of the workpiece holding chuck 300. The operator inserts the holding portion H of the workpiece WK into the hole where the chuck portion 302 of the workpiece holding chuck 300 is formed, from the tapered portion 304 side.

[0077] Next, the operator holds the workpiece WK with the workpiece holding chuck 100. Specifically, the operator operates the machine tool to displace the chuck puller 420 to the left in the diagram, thereby pulling the workpiece holding chuck 300 into the chuck operating shaft 401. As a result, the tapered portion 304 of the workpiece holding chuck 300 is strongly pressed against the machine-side tapered portion 402.

[0078] In this case, the thicker portion 303 of the workpiece holding chuck 300 is pushed radially inward by the tapered portion 402 on the device side. As a result, the thin-walled portion 305 of the workpiece holding chuck 300 elastically deforms from a circular curved surface state to a further curved state. In this case, since a small thicker portion 310 is formed on the thin-walled portion 305 of the workpiece holding chuck 300, damage during elastic deformation is suppressed. As a result, the inner diameter of the chuck portion 302 of the workpiece holding chuck 300 contracts, and the workpiece WK can be held by pressing the held portion H of the workpiece WK radially inward. In other words, the operator can hold the workpiece WK within the workpiece holder 400 using the workpiece holding chuck 300.

[0079] The operator can then perform machining operations such as cutting or grinding on the workpiece WK by operating a machine tool. Since this machining operation on the workpiece WK is not directly related to the present invention, its explanation will be omitted.

[0080] Next, when the workpiece WK has been processed, the operator removes the workpiece WK from the workpiece holder 400. Specifically, the operator operates the machine tool to displace the chuck pull-in tool 420 to the right in the diagram, thereby pushing the workpiece holding chuck 300 out of the chuck operating shaft 401.

[0081] As a result, the pressure exerted on the thicker portion 303 by the tapered portion 402 on the device side of the workpiece holding chuck 300 is reduced, causing the thin-walled portion 305 to return to its curved shape. In this case, the workpiece holding chuck 300 is less susceptible to damage during elastic deformation because a small-thick portion 310 is formed on the thin-walled portion 305. As a result, the outer diameter of the chuck portion 302 of the workpiece holding chuck 300 is increased, reducing the radially inward pressure on the workpiece WK against the held portion H, thereby releasing the workpiece WK from being held. Therefore, the operator can remove the workpiece WK from the workpiece holding chuck 300 and the workpiece holder 400 by pulling the workpiece WK out of the workpiece holding chuck 300 and the workpiece holder 400.

[0082] Furthermore, the operator can also remove the workpiece holding chuck 300 from the workpiece holder 400. Specifically, the operator can remove the workpiece holding chuck 300 from the workpiece holder 400 by disengaging the screw connection of the connecting portion 307 of the workpiece holding chuck 300 from the male screw portion 421 of the chuck pull-in tool 420 and pulling the workpiece holding chuck 300 out of the chuck operating shaft 401.

[0083] As can be understood from the above description of operation, according to the second embodiment, the workpiece holding chuck 300 has a thick section 303 having a tapered section 304 and a thin section 305 between the thick section 303, and a small thick section 310 with an overhang amount less than or equal to the overhang amount of the thick section 303 is formed in this thin section 305. Therefore, it is possible to increase the amount of expansion and contraction while suppressing the decrease in rigidity of the thin section 305 and making it easier to deform, thereby reducing the force required for expansion and contraction.

[0084] Furthermore, the present invention is not limited to the embodiments described above, and various modifications are possible as long as they do not depart from the purpose of the present invention. In the description of the modified examples, the same reference numerals are used for parts that are the same as those in the embodiments described above and are not given new reference numerals.

[0085] For example, in each of the above embodiments, six thick-walled portions 103, 303, six tapered portions 104, 304, and six thin-walled portions 105, 305 are formed. However, it is sufficient to have at least three thick-walled portions 103, 303, six tapered portions 104, 304, and six thin-walled portions 105, 305.

[0086] Furthermore, in each of the above embodiments, the thin-walled portions 110 and 310 are configured to protrude from the thin-walled portions 105 and 305 via a curved surface. This allows the workpiece holding chucks 100 and 300 to minimize damage between the thin-walled portions 105 and 305 and the thin-walled portions 110 and 310 during deformation of the thin-walled portions 105 and 305, making deformation easier. However, the thin-walled portions 110 and 310 can also be configured to protrude from the thin-walled portions 105 and 305 via a pointed shape where two planes are connected at an obtuse, right, or acute angle.

[0087] Furthermore, in each of the above embodiments, the small-walled portions 110 and 310 are formed in the central portion between two circumferentially adjacent walled portions 103 and 303. This allows the workpiece holding chucks 100 and 300 to hold the workpiece WK accurately by suppressing uneven or biased deformation of the thin-walled portions 105 and 305 and ensuring uniform deformation. However, the small-walled portions 110 and 310 can also be positioned biased toward one of the two circumferentially adjacent walled portions 103 and 303. In addition, two or more small-walled portions 110 and 310 can be formed between two circumferentially adjacent walled portions 103 and 303.

[0088] Furthermore, in each of the above embodiments, the thin-walled portions 105 and 305 were formed on the back side of the chuck portions 102 and 302. However, the thin-walled portions 105 and 305 can also be formed radially inward or radially outward from the chuck portions 102 and 302.

[0089] Furthermore, in each of the above embodiments, the thick-walled portions 103, 303 and the thin-walled portions 105, 305 are connected via curved boundary portions 106, 306. This makes it possible to reduce damage between the thin-walled portions 105, 305 and the thick-walled portions 103, 303 during deformation of the thin-walled portions 105, 305, and to facilitate deformation. However, the thick-walled portions 103, 303 and the thin-walled portions 105, 305 can also be configured to be connected via a pointed shape where two planes are connected at an obtuse, right, or acute angle.

[0090] Furthermore, in each of the above embodiments, the surface of the thin-walled portion 110 opposite to the thick-walled portion 103 is formed as a curved surface as the chuck portion 102. However, as shown in Figure 7, the thin-walled portion 110 can have a recessed relief portion 112 formed on the surface of the thin-walled portion 110 opposite to the thick-walled portion 103. This allows the workpiece holding chuck 100 to increase the amount of expansion and contraction of the entire chuck body 101 by thinning the thin-walled portion 110 with the relief portion 112 and by expanding or contracting the groove width of the relief portion 112. In addition, the thin-walled portion 310 can also have a recessed relief portion formed on the surface of the thin-walled portion 310 opposite to the thick-walled portion 103, similar to the thin-walled portion 110.

[0091] Furthermore, in each of the above embodiments, the chuck body 101 is formed in a cylindrical shape that is continuously connected in the circumferential direction. However, as shown in Figure 8, the chuck body 101 can also be formed in a C-shape when viewed from the coaxial direction by a notch portion 113 that extends through in the axial direction. In this case, the notch portion 113 can be provided in a thin-walled portion 105 or a small-walled portion 110 instead of a thick-walled portion 103. This makes it easier to expand and contract the chuck body 101, 301 of the workpiece holding chucks 100, 300, and also increases the amount of expansion and contraction. Similarly to the chuck body 301, the chuck body 301 can also be formed in a C-shape when viewed from the coaxial direction by a notch portion that extends through in the axial direction. [Explanation of Symbols]

[0092] WK…workpiece, H…holding portion, O…center of chuck body, α…forming angle of thin-walled portion relative to the center of chuck body, β…forming angle of thick-walled portion relative to the center of chuck body, γ…forming angle γ of small-walled portion relative to the center of chuck body, Lα…circumferential length of the radially outer side of the thin-walled portion, Lβ…circumferential length of the radially outer side of the thick-walled portion, T1…amount of protrusion of small-walled portion from thin-walled portion, T2…height of thick-walled portion from thin-walled portion, S…tool, 100...workpiece holding chuck, 101...chuck body, 102...chuck section, 103...thick section, 104...tapered section, 105...thin section, 106...boundary section, 110...Thin wall section, 111...Boundary section, 112...Relief section, 113...Notched section, 200...Workpiece holder, 201...Chuck operating shaft, 202...Device side tapered section, 203...Collar guide section, 204...Pressing collar, 205...Male thread section, 206...Operator, 207...Spring holder section, 208...Spring, 208a...Spacer, 209...Flange section, 210...Spindle connection section, 300...Workpiece holding chuck, 301...Chuck body, 302...Chuck section, 303...Thick section, 304...Tapered section, 305...Thin section, 306...Boundary section, 307...Connecting section, 310...Small thick part, 311...Boundary part, 400...Workpiece holder, 401...Chuck operating shaft, 402...Tapered section on the device side, 410... Main spindle connection part, 420...Chuck retractor, 421...Male screw part, 422...Fixing wall.

Claims

1. A workpiece holding chuck that detachably holds a cylindrical workpiece, A chuck body formed in a cylindrical shape, A chuck portion formed on the outer circumference of the chuck body to press against the inner circumference of the workpiece, The chuck body has at least three thickened portions formed along the circumferential direction on its inner circumference, which protrude radially inward from the chuck body, On each inner surface of the three or more thickened portions formed above, which are the radially inner surfaces, there is a tapered portion formed in a tapered shape along the axial direction of the chuck body, the inner diameter of which changes continuously. The material comprises two thick sections adjacent to each other in the circumferential direction, with a thin section formed to be thinner than the aforementioned thick sections. The thin-walled portion is A workpiece holding chuck characterized by having a small thickness portion that protrudes radially inward from the chuck body with an amount of protrusion less than or equal to the aforementioned thickness portion.

2. A workpiece holding chuck that detachably holds a cylindrical workpiece, A chuck body formed in a cylindrical shape, A chuck portion formed on the inner circumference of the chuck body to press against the outer surface of the workpiece, The chuck body has at least three or more thickened portions formed along the circumferential direction on its outer circumference, which protrude radially outward from the chuck body, On each of the three or more thickened portions, which are the radially outer surfaces, a tapered portion is formed in a tapered shape along the axial direction of the chuck body, wherein the outer diameter changes continuously. The material comprises two thick sections adjacent to each other in the circumferential direction, with a thin section formed to be thinner than the aforementioned thick sections. The thin-walled portion is A workpiece holding chuck characterized by having a small-walled portion that protrudes radially outward from the chuck body with an amount of protrusion less than or equal to the aforementioned wall thickness portion.

3. In the workpiece holding chuck described in claim 1 or claim 2, The aforementioned thin-walled portion is, A workpiece holding chuck characterized by having a curved surface that rises relative to the thin-walled portion.

4. In a workpiece holding chuck according to any one of claims 1 to 3, The aforementioned thin-walled portion is, A workpiece holding chuck characterized by being formed in the central portion between two adjacent thickened portions.

5. In a workpiece holding chuck according to any one of claims 1 to 4, The aforementioned thin-walled portion is, A workpiece holding chuck characterized in that the amount of overhang is 1 / 10 or less of the amount of overhang of the thickened portion.

6. In a workpiece holding chuck according to any one of claims 1 to 5, The aforementioned thin-walled portion is, A workpiece holding chuck characterized by having a concave relief portion on the side opposite to the aforementioned thick portion.

7. In a workpiece holding chuck according to any one of claims 1 to 6, A workpiece holding chuck characterized in that the thick portion and the thin portion are connected by a curved surface.

8. In a workpiece holding chuck according to any one of claims 1 to 7, The chuck body is, A workpiece holding chuck characterized by being formed in a C-shape when viewed from the same axial direction by a notch that extends through in the axial direction.

9. A workpiece holder for holding a workpiece holding chuck as described in any one of claims 1 to 8, A tapered portion on the device side that is formed in a tapered shape and fits into the tapered portion of the workpiece holding chuck, A workpiece processing apparatus characterized by comprising a chuck displacement means for displacing the workpiece holding chuck relative to the tapered portion on the apparatus side.

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