Tool holder

Abstract

To provide a technique capable of easily rotating a pressure adjustment screw for adjusting a pressure of a fluid filled into a pressurization space.SOLUTION: Pressure adjustment means 300 for adjusting a pressure of fluid filled into pressurization spaces 205a and 205b includes a pressurization chamber 113S, a piston 310, an adapter 330, and a pressure adjustment screw 340. An adapter outer peripheral surface 332 of the adapter 330 and a cylinder wall surface part 113d are formed so as to be capable of being threadably engageable. The outer peripheral surface of a screw part 340a of the pressure adjustment screw 340 and an adapter inner peripheral surface 331 of the adapter 330 are formed so as to be capable of being threadably engageable. Movement of the piston 310 for regulating the pressurization chamber 113S is regulated to a side where the pressure of the fluid in the pressurization chamber 113S is lowered, by the pressure adjustment screw 340. The maximum outer diameter of the screw part 340a of the pressure adjustment screw 340 is set to be equal to or less than the maximum outer diameter of the piston 310.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a tool holder that uses fluid pressure to hold a tool, and more particularly to a tool holder that adjusts the fluid pressure using a pressure adjustment screw. [Background technology]

[0002] Tool holders that use the pressure of a fluid (e.g., oil) (sometimes called "hydro holders") are used as tool holders for holding tools. A tool holder that uses the pressure of a fluid is disclosed in, for example, Patent Document 1 (JP 2015-39753 A). Figures 6 to 8 show a tool holder 500 disclosed in Patent Document 1. Figure 6 is a cross-sectional view of the tool holder 500, Figure 7 is an enlarged view of a main part of Figure 6, and Figure 8 is a cross-sectional view of Figure 6 taken along line VIII-VIII. The tool holder 500 includes a main body member 510, a sleeve 600, and pressure adjustment devices 700 and 800. The sleeve 600 is fixed to the main body member 510 while inserted into a main body member inner space (more specifically, main body member inner space portions 510a and 510b) defined by the main body member inner circumferential surface 511. This forms pressurized spaces 605a and 605b between the sleeve outer circumferential surface 602 and the main body member inner circumferential surface 511 at locations corresponding to the gripping portions 604a and 604b, which are elastically deformable along the radial direction. The pressurized spaces 605a and 605b are filled with a fluid (e.g., oil). When the pressure of the fluid filling the pressurized spaces 605a and 605b increases, the gripping portions 604a and 604b elastically deform radially inward, thereby clamping a tool inserted in the sleeve inner space 600a. The pressure adjustment means 700 (800) adjusts the pressure of the fluid filled in the pressurized spaces 605a, 605b. The pressure adjustment means 700 (800) includes a piston 710 (810) and a pressure adjustment screw 740 (840) disposed in the cylinder chamber 513 (516), and a pressurized chamber 513S (516S) formed in the cylinder chamber 513 (516). The pressurized chamber 513S (516S) communicates with the pressurized spaces 605a, 605b via a communication passage 514A (517A) and a main body member passage 515 (518). The pressurizing chamber 513S (516S) is defined by the cylinder wall surface that forms the cylinder chamber 513 (516) and the piston 710 (810). The pressure adjusting screw 740 (840) is disposed on the opposite side of the piston 710 (810) from the pressurizing chamber 513S (516S).

[0003] The pressure of the fluid filling the pressurizing chamber 513S (516S) acts as a force to move the piston 710 (810) toward the pressure adjustment screw 740 (840). The movement of the piston 710 (810) toward the pressure adjustment screw 740 (840) is regulated by the position of the pressure adjustment screw 740 (840). In other words, the pressure of the fluid filling the pressurizing chamber 513S (516S) is adjusted by the position of the pressure adjustment screw 740 (840). The position of the pressure adjustment screw 740 (840) is adjusted by rotating the pressure adjustment screw 740 (840) using, for example, a screwdriver or a wrench. For example, when the pressure adjustment screw 740 (840) is rotated in a first direction, the pressure adjustment screw 740 (840) moves toward the pressurizing chamber 513S (516S). This increases the pressure of the fluid filling the pressurizing chamber 513S (516S), i.e., the pressurizing spaces 605a, 605b. In this case, the gripping portions 604a, 604b elastically deform radially inward, and a tool inserted in the sleeve inner space 600a is clamped. On the other hand, when the pressure adjustment screw 740 (840) is rotated in a second direction opposite to the first direction, the pressure adjustment screw 740 (840) moves away from the pressurizing chamber 513S (516S). This reduces the pressure of the fluid filling the pressurizing chamber 513S (516S), i.e., the pressurizing spaces 605a, 605b. In this case, the gripping portions 604a, 604b elastically recover radially outward, allowing a tool to be inserted into the sleeve inner space 600a or a tool inserted in the sleeve inner space 600a to be removed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-39753 Summary of the Invention [Problem to be solved by the invention]

[0005] 7 and 8, the cylinder chamber 513 (516) has a cylinder chamber portion 513A (516A) formed on the rear side by a cylinder wall surface portion 513d (516d), and a cylinder chamber portion 513B (516B) formed on the opening side by a cylinder wall surface portion 513b (516b). The cylinder chamber portion 513B (516B) on the opening side has an inner diameter larger than the inner diameter of the cylinder chamber portion 513A (516A) on the rear side. In the conventional tool holder 500, a male thread that can be threadably coupled to a female thread formed on the cylinder wall surface portion 513B (516B) is formed on the outer peripheral surface 742 (842) of the pressure adjusting screw 740 (840). Therefore, the maximum outer diameter n of the threaded portion of the pressure adjusting screw 740 (840) is larger than the maximum outer diameter m of the piston 710 (810) (n>m). In the conventional tool holder 500, the pressure of the fluid can be adjusted without significantly rotating the pressure adjustment screw 740 (840). However, when rotating the pressure adjustment screw 740 (840), particularly when rotating in a direction that increases the pressure of the fluid, a large force is required to rotate the pressure adjustment screw 740 (840). The present invention has been devised in view of the above points, and has as its object to provide a tool holder that allows easy rotation of a pressure adjustment screw for adjusting the pressure of a fluid. [Means for solving the problem]

[0006] The tool holder of the present invention comprises a main body and a pressure adjusting means. The main body has a tool insertion space, a pressure space, and a gripping portion. The tool insertion space is defined by a tool insertion space defining surface and extends along the axial direction. The pressurizing space is provided radially outward from the tool insertion space defining surface and is filled with a fluid. The gripping portion is formed between the pressurizing space and the tool insertion space defining surface. The gripping portion is configured to be elastically deformable along a radial direction intersecting the axial direction. The pressure adjusting means is configured to adjust the pressure of the fluid filled in the pressurized space. When the pressure adjusting means increases the pressure of the fluid filled in the pressurized space, the gripping portion elastically deforms radially inward (toward the tool insertion space) along the radial direction. The pressure adjusting means includes a cylinder chamber defined by a cylinder wall, a pressure adjusting screw and a piston disposed within the cylinder chamber, and a pressurizing chamber formed within the cylinder chamber. The cylinder chamber extends in a predetermined direction. Preferably, the cylinder chamber is formed in the main body. The pressure adjusting screw has a threaded portion extending in a predetermined direction. A male thread is formed on the outer peripheral surface of the threaded portion so as to be threadably coupled to a female thread provided on the cylinder wall surface. The female thread provided on the cylinder wall surface includes a female thread formed on the cylinder wall surface or a female thread provided on a member connected to the cylinder wall surface. Preferably, the pressure adjusting screw has a head portion formed with a hole into which a screwdriver or wrench is inserted to rotate the pressure adjusting screw. The piston is disposed on a first side of the pressure adjustment screw in a predetermined direction. The pressure adjustment screw is configured to restrict movement of the piston along the predetermined direction toward a second side opposite the first side. Movement of the piston along the predetermined direction toward the second side may be configured to be restricted directly by the pressure adjustment screw, or may be configured to be restricted indirectly via another member. The pressurizing chamber is formed on a first side of the piston along a predetermined direction, and communicates with the pressurizing space. In the present invention, the maximum outer diameter of the threaded portion of the pressure adjusting screw is set to be equal to or smaller than the maximum outer diameter of the piston, which allows the pressure adjusting screw to be turned with less force than in conventional tool holders. In the present invention, the pressure adjusting screw can be easily rotated. In another aspect of the present invention, the pressure adjusting means includes an adapter disposed in the cylinder chamber, the adapter being disposed on a second side of the piston along the predetermined direction. Furthermore, a female screw is formed on the wall surface of the cylinder. The adapter is formed in a cylindrical shape extending in a predetermined direction and has an inner peripheral surface and an outer peripheral surface. The inner peripheral surface of the adapter is formed with a female thread that can be threadedly coupled with a male thread formed on the outer peripheral surface of the threaded portion of the pressure adjusting screw. The outer peripheral surface of the adapter is formed with a male thread that can be threadedly coupled with a female thread formed on the wall surface of the cylinder. In this embodiment, the maximum outer diameter of the threaded portion of the pressure adjusting screw can be easily set to be equal to or smaller than the maximum outer diameter of the piston. In another embodiment of the present invention, the cylinder wall includes first to third cylinder wall portions, the first cylinder wall portion forming a first cylinder chamber portion having a first inner diameter, the second cylinder wall portion forming a second cylinder chamber portion having a second inner diameter larger than the first inner diameter, the second cylinder chamber portion being disposed on a second side in a predetermined direction from the first cylinder chamber portion, and the second cylinder wall portion connecting the first cylinder wall portion and the second cylinder wall portion. A female screw is formed on the wall surface of the second cylinder, and can be threadedly coupled to a male screw formed on the outer peripheral surface of the adapter. In this embodiment, the pressure adjusting screw having a threaded portion whose maximum outer diameter is set to be equal to or smaller than the maximum outer diameter of the piston can be reliably held. In a different aspect of the invention, the pressure regulating means includes a first pressure regulating means and a second pressure regulating means. The first pressure adjustment means includes a first cylinder chamber formed by a first cylinder wall surface, a first pressure adjustment screw and a first piston arranged in the first cylinder chamber, and a first pressurizing chamber formed in the first cylinder chamber. The first pressure adjusting screw has a first threaded portion extending in a first direction, and a male thread is formed on the outer circumferential surface of the first threaded portion so as to be threadably coupled to a female thread provided on the wall surface of the first cylinder. The first piston is disposed on a first side of the first pressure adjustment screw in the first direction, and the first pressure adjustment screw is configured to restrict movement of the first piston along the first direction to a second side opposite the first side. The first pressurizing chamber is formed on a first side of the first piston along a first direction, and communicates with the pressurizing space. The second pressure adjustment means includes a second cylinder chamber formed by the second cylinder wall surface, a second pressure adjustment screw and a second piston arranged in the second cylinder chamber, and a second pressurizing chamber formed in the second cylinder chamber. The second pressure adjusting screw has a second threaded portion extending in a second direction, and the outer circumferential surface of the second threaded portion is formed with a male thread that can be threadably coupled to a female thread provided on the wall surface of the second cylinder. The second piston is disposed on the first side of the second pressure adjustment screw along the second direction, and the second pressure adjustment screw is configured to restrict movement of the second piston along the second direction toward the second side opposite the first side. The second pressurizing chamber is formed on the first side of the second piston along the second direction, and communicates with the pressurizing space. The maximum outer diameter of the first threaded portion of the first pressure adjusting screw is set to be equal to or smaller than the maximum outer diameter of the first piston, and the maximum outer diameter of the second threaded portion of the second pressure adjusting screw is set to be equal to or smaller than the maximum outer diameter of the second piston. In this embodiment, the pressure of the fluid filled in the pressurized space can be easily adjusted. In a different embodiment of the present invention, the first cylinder chamber and the second cylinder chamber are formed at positions opposite each other across the center line of the main body of the main body, so that the first direction and the second direction are parallel (including "approximately parallel"). In this embodiment, the first pressure adjusting means and the second pressure adjusting means can be arranged in a well-balanced manner. [Effects of the Invention]

[0007] In the tool holder of the present invention, the pressure adjusting screw for adjusting the pressure of the fluid filled in the pressurized space can be easily rotated. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of a tool holder according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of FIG. 1 taken along line II-II. [Figure 3] FIG. 2 is an enlarged view of a main part of FIG. [Figure 4] FIG. 1 is an assembly view of an embodiment of a tool holder. [Figure 5]FIG. 2 is a cross-sectional view of FIG. 1 taken along line VV. [Figure 6] FIG. 1 is a cross-sectional view of a conventional tool holder. [Figure 7] FIG. 1 is an assembly diagram of a conventional tool holder. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a tool holder according to the present invention will be described with reference to the drawings. 1 to 4 show a tool holder 100 according to one embodiment. FIG. 1 is a cross-sectional view of the tool holder 100. FIG. 2 is a cross-sectional view of FIG. 1 taken along line II-II. FIG. 3 is an enlarged view of a main part of FIG. 1. FIG. 4 is an assembly diagram of the tool holder 100. FIG. 5 is a cross-sectional view of FIG. 1 taken along line VV. In the following description, the direction in which the body member center line P of the body member 110 extends (the X direction shown in FIG. 1) will be referred to as the "axial direction." When viewed from one axial side (see FIG. 5), the direction of a line passing through the body member center line P will be referred to as the "radial direction," and the circumferential direction around the body member center line P will be referred to as the "circumferential direction." The side along the axial direction from which a tool is inserted (the side indicated by the arrow X1 in FIG. 1) will be referred to as the "first axial side," "axial tip side," or "tip side," and the side opposite to the side from which the tool is inserted (the side indicated by the arrow X2 in FIG. 1) will be referred to as the "second axial side," "axial rear end side," or "rear end side." The direction in which the first cylinder chamber 113 extends (the Y direction shown in FIG. 5) is referred to as the "first direction." One side along the first direction (the arrow Y1 side in FIG. 5) is referred to as the "first direction first side," and the other side along the first direction (the opposite side to the one side) (the arrow Y2 side in FIG. 5) is referred to as the "first direction second side." The direction in which the second cylinder chamber 116 extends (the Z direction shown in FIG. 5) is referred to as the "second direction." One side along the second direction (the arrow Z1 side in FIG. 5) is referred to as the "second direction first side," and the other side along the second direction (the opposite side to the one side) (the arrow Z2 side in FIG. 5) is referred to as the "second direction second side."

[0010] The tool holder 100 comprises a body member 110 , a sleeve 200 , a first pressure adjusting means 300 and a second pressure adjusting means 400 .

[0011] The main body member 110 is formed in a cylindrical shape and has a main body member front end surface 110A, a main body member rear end surface 110B, a main body member inner circumferential surface 111, and a main body member outer circumferential surface 112. The main body member inner circumferential surface 111 includes main body member inner circumferential surface portions 111a to 111d from the front end to the rear end. The main body member inner circumferential surface portions 111a, 111c, and 111e have circular cross sections. The main body member inner circumferential surface 111 defines a main body member internal space that extends along the axial direction and opens to the main body member front end surface 110A and the main body member rear end surface 110B. The main body member internal space includes a main body member internal space portion 110a defined by the main body member inner circumferential surface portion 111a, a main body member internal space portion 110b defined by the main body member inner circumferential surface portions 111c and 111d, and a main body member internal space portion 110c defined by the main body member inner circumferential surface portion 110e. The main body member outer peripheral surface 112 has main body member outer peripheral surface portions 112a to 112c from the front end to the rear end. The main body member outer peripheral surface portion 112c is formed as a tapered surface extending so that the outer diameter decreases from the front end to the rear end. The main body member outer peripheral surface portion 112c forms the shank portion of the tool holder 100. The shank portion formed by the main body member outer peripheral surface portion 112c is formed so as to be capable of tapered fit with the tapered inner peripheral surface (spindle inner peripheral surface portion) of the spindle of the machine tool.

[0012] The sleeve 200 is formed in a cylindrical shape and has a sleeve front end surface 200A, a sleeve rear end surface 200B, a sleeve inner peripheral surface 201, and a sleeve outer peripheral surface 202. The sleeve inner peripheral surface 201 defines a sleeve inner space 200a that extends along the axial direction and opens to a sleeve front end surface 200A and a sleeve rear end surface 200B. The sleeve inner section 200a (sleeve inner peripheral surface 201) has a circular cross section. A tool shank of a tool is inserted into the sleeve inner space 200a. The sleeve inner space 200a corresponds to the "tool insertion space" of the present invention, and the sleeve inner peripheral surface 201 corresponds to the "tool insertion space forming surface" of the present invention.

[0013] The sleeve outer peripheral surface 202 includes sleeve outer peripheral surface portions 202a to 202f from the front end side to the rear end side. Sleeve outer peripheral surface portion 202a is formed radially outward of sleeve outer peripheral surface portions 202c to 202f. Sleeve tip surface 200A and sleeve outer peripheral surface portions 202a and 202b form flange portion 200C that protrudes radially outward. Sleeve outer peripheral surface portions 202c and 202e are recessed radially inward from sleeve outer peripheral surface portions 202d and 202f in a stepped shape. Sleeve outer peripheral surface portions 202c and 202e form recesses 203a and 203b that are recessed radially inward in a stepped shape. The outer diameter (diameter) of the sleeve outer peripheral surface portion 202d is set to be larger than the outer diameters of the sleeve outer peripheral surface portions 202c and 202e, and smaller than the outer diameter of the sleeve outer peripheral surface portion 202f. The sleeve outer peripheral surface 202 (sleeve outer peripheral surface portions 202a, 202c to 202f) has a circular cross section. Between the sleeve inner peripheral surface 201 and the sleeve outer peripheral surface portions 202c and 202e, gripping portions 204a and 204b are formed which are elastically deformable along the radial direction. The gripping portions 204a and 204b are features that correspond to the "grip" of this invention.

[0014] The sleeve 200 is inserted into the body member inner space from the tip side, with the flange portion 200C of the sleeve 200 being inserted into the body member inner space portion 110a. After inserting the sleeve 200 into the space inside the main body member, the sleeve 200 is fixed to the main body member 110. For example, outer peripheral surface portions 202a, 202b, and 202f of the sleeve are fixed to inner peripheral surface portions 111a, 111b, and 111c of the main body member, respectively, using a brazing method or an electron beam welding method. The fixing method and fixing positions can be changed as appropriate. By fixing the sleeve 200 to the main body member 110, pressurized spaces 205a, 205b extending in the circumferential direction are formed between the sleeve outer peripheral surface portions 202c, 202e and the main body member inner peripheral surface 111 (main body member inner peripheral surface portion 111c). In addition, a communication passage 205c extending in the circumferential direction and the axial direction is formed between the sleeve outer peripheral surface portion 202d and the main body member inner peripheral surface 111 (main body member inner peripheral surface portion 111c) to communicate between the pressurized spaces 205a and 205b. The pressurized spaces 205a, 205b and the communication passage 205c are filled with a fluid (for example, oil). Body member 110 is provided with body member passages that communicate with pressurized spaces 205a and 205b. In this embodiment, first body member passage 115 and second body member passage 118, each having openings 115a and 118a on one side, are provided in pressurized space 205b. The other sides of first body member passage 115 and second body member passage 118 open to first communication chamber 114A and second communication chamber 117A (described below), respectively.

[0015] In this embodiment, the main body member 110 and the sleeve 200 constitute the "main body" of the present invention. The "main body portion inner space" of the present invention is formed by the main body member inner space (main body member inner space portions 110c, 110d) and the sleeve inner space 200a. The "main body portion inner peripheral surface" of the present invention is formed by the main body member inner periphery (main body member inner peripheral surface portions 111e, 111f) and the sleeve inner peripheral surface 201. The sleeve inner space 200a constitutes the "tool insertion space" of the present invention. The sleeve inner peripheral surface 201 constitutes the "tool insertion space forming surface" of the present invention. The gripping portions 204a and 204b form the "grip portion" of the present invention. The pressurized spaces 205a and 205b form the "pressurized space" of the present invention. The "body passage" of the present invention is constituted by the first body member passage 115 and the second body member passage 116. The first body member passage 115 and the second body member passage 116 correspond to the "first body member passage" and the "second body member passage" of the present invention, respectively. The center line P of the main body member corresponds to the "main body center line" of this invention.

[0016] When the pressure of the fluid filled in the pressurized spaces 205a, 205b increases, the gripping portions 204a, 204b elastically deform radially inward (toward the sleeve inner space 200a), thereby clamping the tool (more specifically, the tool shank) inserted into the sleeve inner space 200a between the gripping portions 204a, 204b. On the other hand, when the pressure of the fluid filled in the pressurized spaces 205a, 205b decreases, the gripping portions 204a, 205b elastically recover radially outward (toward the opposite side from the sleeve inner space 200a), thereby making it possible to insert a tool into the sleeve inner space 200a or to remove a tool inserted in the sleeve inner space 200a.

[0017] The first pressure control means 300 and the second pressure adjustment means 400 adjust the pressure of the fluid filled in the pressurizing chambers 205a and 205b. First, the configuration of the first pressure adjusting means 300 will be described. The first pressure adjusting means 300 includes a first cylinder chamber 113 , a first piston 310 , a first O-ring 320 , a first adapter 330 , and a first pressure adjusting screw 340 .

[0018] The first cylinder chamber 113 is formed in the main body member 110 and opens to the main body member outer circumferential surface 112 (main body member outer circumferential surface portion 112b). The first cylinder chamber 113 extends in a predetermined direction at a position radially outward from the main body member inner circumferential surface 111. In this embodiment, the first cylinder chamber 113 extends along a first direction (Y direction shown in FIG. 5) that is perpendicular (including "substantially perpendicular") to the axial direction. The first cylinder chamber 113 is formed by the first cylinder wall surface. The first cylinder wall surface includes cylinder wall surface portions 113a to 113d. The cylinder wall surface portion 113 a is disposed at the end of the first cylinder chamber 113 on the first side in the first direction, and forms the bottom surface of the first cylinder chamber 113 . Cylinder wall surface portion 113b is disposed on the first side in the first direction relative to cylinder wall surface portion 113d. Cylinder wall surface portions 113b and 113d extend along the first direction and have a circular cross section. In this embodiment, the inner diameter of cylinder wall surface portion 113d is set to be larger than the inner diameter of cylinder wall surface portion 113b. Cylinder wall surface portion 113c is a stepped surface connecting cylinder wall surface portions 113b and 113d. The cylinder wall surface portion 113b forms a first cylinder chamber portion 113A, and the cylinder wall surface portion 113d forms a second cylinder chamber portion 113B. That is, the first cylinder chamber 113 includes the first cylinder chamber portion 113A and the second cylinder chamber portion 113B, which is disposed on the second side in the first direction (opposite the first side in the first direction) of the first cylinder chamber portion 113A. A female screw that can be threadedly coupled to a male screw (described later) formed on an adapter outer peripheral surface 332 of the adapter 330 is formed on the cylinder wall surface portion 113d. Cylinder wall surface portions 113b, 113d, and 113c correspond to the "first cylinder wall surface portion," "second cylinder wall surface portion," and "third cylinder wall surface portion" of the present invention, respectively.

[0019] First piston 310 extends along a first direction and has piston end faces 310A and 310B on first and second sides in the first direction, as well as a piston outer circumferential surface 312. Piston outer circumferential surface 312 includes piston outer circumferential surface portions 312a to 312e from the first side to the second side along the first direction. Piston outer peripheral surface portions 312a, 312c, 312e extend along a first direction and have a circular cross section. Piston outer peripheral surface portions 312b to 312d form groove 313 extending in the circumferential direction. The first piston 310 is inserted into the first cylinder chamber 113 with the O-ring 320 disposed in the groove 313. As a result, a first pressurizing chamber 113S is formed on the first side in the first direction from the first piston 310. That is, the first pressurizing chamber 113S is defined by the first piston 310 and the first cylinder wall surface (cylinder wall surface portions 113a, 113b).

[0020] The main body member 110 is formed with a first communication hole 114 that opens to the main body member outer circumferential surface 112 (main body member outer circumferential surface portion 112b). The first communication hole 114 is formed by a hole wall surface. The extending direction of the first communication hole 114 is set appropriately. The hole wall surface includes hole wall surface portions 114a to 114d. Hole wall surface portions 114b and 114d are formed to have a circular cross section. The inner diameter of hole wall surface portion 114b is set smaller than the inner diameter of hole wall surface portion 114d. A sealing steel ball 350 and a screw 360 are disposed in the first communication hole 114 . The screw 360 is positioned closer to the opening of the first communicating hole 114 than the hard ball 350. An external thread is formed on the outer circumferential surface 362 of the screw 360 so that it can be threadably coupled to the internal thread formed in the hole wall surface portion 114d. By rotating the screw 360, the hard ball 350 is positioned so that it abuts against the hole wall surface portion 114c. This forms a communicating chamber 114A in the first communicating hole 114 between the hard ball 350 and the hole wall surface portion 114a. Communication chamber 114A communicates with pressurizing chamber 113S. The other end of first main body member passage 115 opens into hole wall portion 114b. That is, communication chamber 114A communicates with pressurizing spaces 205a and 205b via first main body member passage 115. A screw 370 is provided to restrict movement of the pressure adjusting screw 340 toward the opening of the first cylinder chamber 113. This prevents the pressure adjusting screw 340 from coming out of the first cylinder chamber 113 when the pressure adjusting screw 340 is rotated. In this embodiment, the pressure of the fluid is adjusted mainly by rotating the first pressure adjustment screw 340. For this reason, a screw 370 is provided only in the first cylinder chamber 113. When adjusting the pressure of the fluid by rotating the second pressure adjustment screw 440 or by rotating the first pressure adjustment screw 430 and the second pressure adjustment screw 440, a similar screw is provided in the second cylinder chamber 116.

[0021] The first adapter 330 is formed in a cylindrical (or annular) shape extending in a first direction. The first adapter 330 has adapter end faces 330A and 330b on a first side and a second side in the first direction, as well as an adapter inner circumferential surface 331 and an adapter outer circumferential surface 332. The inner peripheral surface 331 of the adapter is formed with a female thread that can be threadably coupled to the male thread formed on the outer peripheral surface of the threaded portion 340 a of the pressure adjusting screw 340 . The adapter outer circumferential surface 332 is formed with a male thread that can be threadably coupled to a female thread formed on the cylinder wall surface (cylinder wall surface portion 113d). The first adapter 330 is disposed at a predetermined position on the cylinder wall surface along the first direction by thread engagement between a male thread formed on the adapter outer peripheral surface 332 and a female thread formed on the cylinder wall surface (cylinder wall surface portion 113d). For example, the adapter end surface 330A is disposed at a position facing the cylinder wall surface portion 113c.

[0022] The first pressure adjusting screw 340 extends along a first direction and has pressure adjusting screw end faces 340A and 340B on a first side and a second side in the first direction, as well as a pressure adjusting screw outer circumferential surface 342. The pressure adjustment screw outer peripheral surface 342 has pressure adjustment screw outer peripheral surface portions 342a to 342c. The pressure adjustment screw outer peripheral surface portions 342a and 342c extend along a first direction and have a circular cross section. The outer diameter of the pressure adjustment screw outer peripheral surface portion 342a is set smaller than the outer diameter of the pressure adjustment screw outer peripheral surface portion 342c. The cross-sectional shape of the pressure adjustment screw outer peripheral surface portion 342c is not limited to a circle. The pressure adjusting screw outer peripheral surface portion 342a forms the threaded portion 340a. A male thread is formed on the outer peripheral surface of the threaded portion 340a, i.e., the pressure adjusting screw outer peripheral surface portion 342a, so as to be threadably coupled to the female thread formed on the adapter inner peripheral surface 331 of the adapter 330. The pressure adjusting screw outer peripheral surface portion 342c forms a head portion 340b, which has a hole formed therein into which a screwdriver or wrench for rotating the first pressure adjusting screw 340 is inserted. The tip surface (pressure adjustment screw end surface 340A) of the threaded portion 340a of the first pressure adjustment screw 340 is positioned within the first cylinder chamber portion 113A through the adapter inner space 330a of the adapter 330, utilizing the threaded connection between the male thread formed on the outer peripheral surface of the threaded portion 340a and the female thread formed on the adapter inner peripheral surface 331 of the adapter 330. The pressure of the fluid filled in the pressurizing chamber 113S, which is in communication with the pressurizing spaces 204a and 204b, acts as a force that moves the first piston 310 toward the second side in the first direction (toward the adapter 330). The movement of the first piston 310 toward the second side in the first direction is restricted when the piston end surface 310B of the first piston 310 abuts against the tip surface (pressure adjusting screw end surface 340A) of the threaded portion 340a of the first pressure adjusting screw 340. Therefore, by adjusting the position of the first pressure adjusting screw 340 along the first direction, the volume of the pressurizing chamber 113S, i.e., the pressure of the fluid filled in the pressurizing chamber 113S, can be adjusted.

[0023] Similar to the first pressure adjusting means 300, the second pressure adjusting means 400 has a second cylinder chamber 116, a second piston 410, a second O-ring 420, a second adapter 430, and a second pressure adjusting screw 440. The second cylinder chamber 116 extends in a predetermined direction at a position radially outward from the inner peripheral surface 111 of the main body member. In this embodiment, the second cylinder chamber 116 extends along a second direction (Z direction shown in FIG. 5) perpendicular to (including "substantially perpendicular to") the axial direction at a position opposite the first cylinder chamber 113, across the center line P of the main body member. In this embodiment, the second direction is set parallel to (including "substantially parallel to") the first direction. Note that in this embodiment, the first side and second side of the first direction correspond to the second side and first side of the second direction. The second cylinder chamber 116, second piston 410, second O-ring 420, second adapter 430, and second pressure adjustment screw 440 that constitute the second pressure adjustment means 400 have the same configuration as the first cylinder chamber 113, first piston 310, first O-ring 320, first adapter 330, and first pressure adjustment screw 340 that constitute the first pressure adjustment means 300, so their explanation will be omitted. In addition, a second communication hole 117, a hard ball 450, and a screw 460 having the same configuration as the first communication hole 114, hard ball 350, and screw 360 are provided. The communication chamber 117A communicates with the pressurizing chamber 116S. The other end of the second main body member passage 118 opens into the hole wall surface portion 117b. That is, the communication chamber 117A communicates with the pressurizing spaces 205a and 205b via the second main body member passage 118.

[0024] In this embodiment, the "pressure adjustment means" of the present invention is constituted by at least one of the first pressure adjustment means 300 (first cylinder chamber 113, first piston 310, first adapter 330, first pressure adjustment screw 340, first pressurized chamber 113S) and the second pressure adjustment means 400 (second cylinder chamber 116, second piston 410, second adapter 430, second pressure adjustment screw 440, second pressurized chamber 116S).

[0025] In the conventional tool holder 500 shown in Figures 6 to 8, the maximum outer diameter n of the threaded portion of the first pressure adjusting screw 740 (second pressure adjusting screw 840) is set larger than the maximum outer diameter m of the first piston 710 (second piston 810) (n>m). For this reason, a large force was required to rotate the first pressure adjusting screw 740 (second pressure adjusting screw 840). In other words, it was difficult to rotate the first pressure adjusting screw 740 (second pressure adjusting screw 840). In this embodiment, the first pressure adjusting screw 340 (second pressure adjusting screw 440) has a threaded portion 340a (440a) having a male thread formed on its outer circumferential surface and a head portion 340b (440b) on the second side in the first direction (first side in the second direction) of the threaded portion 340a (440a). The maximum outer diameter N of the threaded portion 340 (440a) is set to be equal to or less than the maximum outer diameter M of the first piston 310 (second piston 410) ([N≦M]). This allows the first pressure adjusting screw 340 (second pressure adjusting screw 440) to be rotated with a force smaller than that required to rotate the first pressure adjusting screw 740 (second pressure adjusting screw 840) of the conventional tool holder 700. In other words, the first pressure adjusting screw 340 (second pressure adjusting screw 440) can be rotated more easily than in the conventional tool holder 700. In particular, in this embodiment, a first adapter 330 (second adapter 440) is provided in which an outer peripheral surface 332 (432) of the adapter is formed with a male thread that can be threadably coupled to a female thread formed on the cylinder wall surface portion 113d (116d), and an inner peripheral surface 331 (431) of the adapter is formed with a female thread that can be threadably coupled to a male thread formed on the outer peripheral surface of the threaded portion 340a (440a). This makes it easy to set the maximum outer diameter N of the threaded portion 340a (440a) of the first pressure adjusting screw 340 (second pressure adjusting screw 440) to be equal to or smaller than the maximum outer diameter M of the first piston 310 (second piston 440). Furthermore, the first pressure adjusting screw 340 (second pressure adjusting screw 440) can be stably held. For example, if the outer diameter of the first piston 310 (second piston 410) is 6 mm, the outer diameter of the threaded portion 340a (440a) can be set to 6 mm (nominal diameter of the threaded portion is M6) or 5 mm (nominal diameter of the threaded portion is M5). Also, if the outer diameter of the first piston 310 (second piston 410) is 10 mm, the outer diameter of the threaded portion 340a (440a) can be set to 10 mm (nominal diameter of the threaded portion is M10), 8 mm (nominal diameter of the threaded portion is M8), or 6 mm (nominal diameter of the threaded portion is M6). The pitch of the male thread formed on the outer peripheral surface of the screw portion 340a (440a) and the female thread formed on the inner peripheral surface of the cylinder wall portion 113d (116d) is set taking into consideration the rotational operability of the first pressure adjustment screw 340 (second pressure adjustment screw 440), etc. It should be noted that since the maximum outer diameter N of the threaded portion 340a (440a) of the first pressure adjusting screw 340 (second pressure adjusting screw 440) is reduced, the amount of rotation of the first pressure adjusting screw 340 (second pressure adjusting screw 440) needs to be increased accordingly. For example, the length of the threaded portion 340a (440a) along the first direction (second direction) needs to be longer than the length of the pressure adjusting screw outer peripheral surface 742 (842) of the pressure adjusting screw 740 (840) used in the conventional tool holder 700.

[0026] The present invention is not limited to the configurations described in the embodiments, and modifications, additions, and deletions can be made as appropriate. The pressure of the fluid in the pressurized space (pressurized chamber) may be adjusted by rotating the first pressure adjustment screw and the second pressure adjustment screw, or by rotating one of the first pressure adjustment screw and the second pressure adjustment screw. In the embodiment, two pressure adjusting means, that is, a first pressure adjusting means and a second pressure adjusting means, are provided, but it is sufficient that at least one pressure adjusting means is provided. In the embodiment, the movement of the piston is restricted by abutting the tip surface of the threaded portion of the pressure adjustment screw against the end surface of the piston, but it is also possible to restrict the movement of the piston by abutting the tip surface of the threaded portion of the pressure adjustment screw against the end surface of the piston indirectly (for example, via another member). In the embodiment, an adapter is provided to reduce the maximum outer diameter of the threaded portion of the pressure adjusting screw, but other methods may also be used. Although a cylinder chamber including a plurality of cylinder chamber portions with different inner diameters is used, the shape of the cylinder chamber can be changed as appropriate. The pressure adjusting screw may have various configurations. In the embodiment, the pressurizing chamber of the pressure adjusting means is connected to the pressurized space via the communication chamber and the body member passage, but the method of connecting the pressurizing chamber to the pressurized space is not limited to this. For example, the communication chamber may be omitted, and the pressurizing chamber may be connected to the pressurized space via the body member passage. In the embodiment, the pressurized space and the communication passage are formed by the main body member and the sleeve, but the pressurized space and the communication passage may be formed in the main body member, in which case the sleeve may be omitted. Although an O-ring is used to seal the piston and the cylinder wall, a sealing member other than an O-ring can also be used. Also, if a seal is not required, the sealing member can be omitted. Each of the configurations described in the embodiments can be used alone, or a plurality of appropriately selected configurations can be used in combination. [Explanation of symbols]

[0027] 100, 500 Tool Holder 110, 510 Main body member 110A, 510A Main body part tip surface 110B, 510B Rear end surface of main body 110a to 110c, 510a to 510c: Main body member inner space portion 111, 511 Inner surface of main body member 112, 512 Outer surface of main body member 112a to 112c, 512a to 512c: outer peripheral surface portions of main body members 113, 116, 513, 516 Cylinder chamber 113A, 113B, 116A, 116B, 513A, 513B, 516A, 516B Cylinder chamber part 113S, 116S, 513S, 516S pressurized chamber 113a-113d, 116a-116d, 513a-513d, 516a-516d Cylinder wall 114, 117, 514, 517 communication hole 114a~114d, 117a~117d, 514a~514d, 517a~517d Hole wall part 115, 118, 515, 518 communication passage 200, 600 sleeves 200A, 600A Sleeve tip surface 200B, 600B sleeve rear end face 200C, 600C Tsuba 200a, 600a Sleeve inner space 201, 601 Inner surface of sleeve 202, 602 Sleeve outer surface 202a to 202f, 602a to 602f: outer peripheral surface of sleeve 203a, 203b, 603a, 603b recesses 204a, 204b, 604a, 604b gripping part 205a, 205b, 605a, 605b pressurized space 205c, 605c communication path 300, 400, 700, 800 Pressure adjustment means 310, 410, 710, 810 pistons 310A, 310B, 410A, 410B, 710A, 710B, 810A, 810B Piston end face 312, 412, 712, 812 Piston outer surface 312a~312e, 412a~412e, 712a~712g, 812a~812g Piston outer surface 313, 323, 713, 813 groove 320, 420, 720, 820 O-ring 330, 430 adapter 330A, 330B, 430A, 430B adapter end face 330a, 430a adapter inner space 331, 431 Adapter inner surface 332, 432 Adapter outer surface 340, 440, 740, 840 pressure adjustment screw 340A, 340B, 440A, 440B, 740A, 740B, 840A, 840B Pressure adjustment screw end face 340a, 440a threaded part 340b, 440b head 342, 442, 742, 842 Pressure adjustment screw outer surface 342a~342c, 442a~442c Pressure adjustment screw outer surface 350, 450, 750, 850 Hardball 360, 460, 760, 860 screws 362, 462, 762, 862 Thread outer surface 370, 770 screws

Claims

1. A main body and a pressure adjusting means are provided. the main body portion includes a tool insertion space forming surface that forms a tool insertion space extending along an axial direction, a pressurizing space, and a grip portion that is provided between the pressurizing space and the tool insertion space forming surface and is elastically deformable along a radial direction that intersects with the axial direction, the pressure adjusting means is capable of adjusting the pressure of the fluid filled in the pressurized space, a tool holder configured to elastically deform the gripping portion toward the tool insertion space along the radial direction when the pressure of the fluid filled in the pressurized space is increased by the pressure adjusting means, the pressure adjusting means includes a cylinder wall surface that forms a cylinder chamber extending along a predetermined direction, a pressure adjusting screw and a piston that are disposed in the cylinder chamber, and a pressurizing chamber that is formed in the cylinder chamber, the pressure adjusting screw has a threaded portion extending along the predetermined direction, and a male thread is formed on an outer circumferential surface of the threaded portion so as to be threadably coupled to a female thread provided on the wall surface of the cylinder, the piston is disposed on a first side of the pressure adjusting screw along the predetermined direction, the pressurizing chamber is formed on the first side of the piston along the predetermined direction so as to communicate with the pressurizing space, The pressure adjusting screw is configured to restrict movement of the piston along the predetermined direction toward a second side opposite to the first side, A tool holder characterized in that the maximum outer diameter of the threaded portion of the pressure adjusting screw is set to be equal to or smaller than the maximum outer diameter of the piston.

2. 2. The tool holder of claim 1, the pressure adjusting means includes an adapter that is disposed in the cylinder chamber at a position on the second side of the piston along the predetermined direction, A female screw is formed on the wall surface of the cylinder, the adapter is formed in a cylindrical shape extending in the predetermined direction, and has an adapter inner surface and an adapter outer surface, the adapter inner surface is formed with a female thread that can be threadedly coupled to the male thread formed on the outer surface of the threaded portion of the pressure adjusting screw, and the adapter outer surface is formed with a male thread that can be threadedly coupled to the female thread formed on the cylinder wall surface.

3. 3. The tool holder of claim 2, the cylinder wall surface includes a first cylinder wall surface portion that forms a first cylinder chamber portion having a first inner diameter, a second cylinder wall surface portion that is disposed on the second side of the first cylinder chamber along the predetermined direction and that forms a second cylinder chamber portion having a second inner diameter that is larger than the first inner diameter, and a third cylinder wall surface portion that connects the first cylinder wall surface portion and the second cylinder wall surface portion, a female thread formed on a wall surface of the second cylinder, the female thread being threadably coupled to the male thread formed on the outer peripheral surface of the adapter;

4. A tool holder according to any one of claims 1 to 3, the pressure adjusting means includes a first pressure adjusting means and a second pressure adjusting means; the first pressure adjusting means includes a first cylinder wall surface that defines a first cylinder chamber extending along a first direction, a first pressure adjusting screw and a first piston that are disposed in the first cylinder chamber, and a first pressurizing chamber that is formed in the first cylinder chamber; the first pressure adjusting screw has a first threaded portion extending along the first direction, and a male thread is formed on an outer circumferential surface of the first threaded portion so as to be threadably coupled to a female thread provided on the first cylinder wall surface side; the first piston is disposed on a first side of the first pressure adjusting screw along the first direction; the first pressurizing chamber is formed on the first side of the first piston along the first direction so as to communicate with the pressurizing space, Movement of the first piston along the first direction toward a second side opposite to the first side is restricted by the first pressure adjusting screw, a maximum outer diameter of the first thread portion of the first pressure adjusting screw is set to be equal to or smaller than a maximum outer diameter of the first piston, the second pressure adjusting means includes a second cylinder wall surface that defines a second cylinder chamber extending along a second direction, a second pressure adjusting screw and a second piston that are disposed in the second cylinder chamber, and a second pressurizing chamber that is formed in the second cylinder chamber, the second pressure adjusting screw has a second threaded portion extending along the second direction, and a male thread is formed on an outer circumferential surface of the second threaded portion so as to be threadably coupled to a female thread provided on the second cylinder wall surface side, the second piston is disposed on a first side of the second pressure adjusting screw along the second direction, the second pressurizing chamber is formed on the first side of the second piston along the second direction so as to communicate with the pressurizing space, Movement of the second piston along the second direction toward a second side opposite to the first side is restricted by the second pressure adjustment screw, a second pressure adjusting screw having a second threaded portion that is equal to or smaller than a maximum outer diameter of the second piston;

5. 5. The tool holder of claim 4, a tool holder having a first cylinder chamber and a second cylinder chamber, the first cylinder chamber and the second cylinder chamber being formed at opposing positions across a center line of the main body portion, with the first direction and the second direction being parallel to each other.

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