Tool unit and machine tool

Abstract

To provide a tool unit that enables fluid to reach a processing point, and a machine tool.SOLUTION: Tool units 10 comprise: a screw-like grind stone 11; a tool holder 12 which holds the screw-like grind stone 11 and comprises flow passages 20, 21, 30 and 31 through which fluid flows; a pump 13 that supplies fluid to the flow passages 20, 21, 30 and 31; a pressure adjusting part 14 that adjusts the pressure of the fluid; an information obtaining part 16 that obtains information concerning the screw-like grind stone 11; and a control part 15 that controls the pressure adjusting part 14 on the basis of the information obtained by the information obtaining part 16. The flow passages 20, 21, 30 and 31 comprise the principal flow passages 20 and 30 extending along a rotary shaft and the branching flow passages 21 and 31 branching and extending from the principal flow passages. Blowout ports 22 and 32 for blowing out fluid are formed in the branching flow passages 21 and 31. The control part 15 controls the pressure adjusting part 14 on the basis of information obtained from the information obtaining part 16, so that the pressure of the fluid is varied.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a tool unit and a machine tool. [Background technology]

[0002] Conventionally, in a machine tool that machines a workpiece with a rotating tool that rotates around a rotation axis, a technology has been described in which a flow passage extending along the direction of the rotation axis is formed, a fluid is circulated within this flow passage, and the fluid is supplied directly to the machining point of the rotating tool (see Patent Documents 1, 2, 3, 4, and 5).

[0003] Patent document 1 describes a technology in which a flow passage is formed within a shaft along its axial direction, an outlet is formed in the tip surface of the shaft connected to the flow passage, and cutting fluid is supplied to the flow passage during machining and ejected from the outlet toward the workpiece.

[0004] Patent Document 2 describes a skiving machine in which a gear-shaped skiving cutter is held at the tip of a holder. The holder has a central flow path for flowing a fluid inside the holder, branch flow paths for flowing the fluid radially outward from the central flow path, an annular flow path for flowing the fluid from the branch flow paths in the circumferential direction, and a plurality of discharge holes for discharging the fluid from the annular flow path toward the teeth of the skiving cutter.

[0005] Patent Document 3 describes a skiving cutter that includes a base that rotates around an axis and a plurality of cutting blades formed on the outer periphery of the base for cutting a workpiece. Each cutting blade includes two or more cutting blades that are configured to be able to share the cutting process for cutting the workpiece, and the skiving cutter includes a branch passage that supplies cutting fluid introduced by a main passage inside the base to the cutting blades.

[0006] Patent Document 4 describes a machine tool that includes a rotating shaft and a tool holder that is detachably engaged with the rotating shaft and has a grinding fluid supply hole, and that performs internal grinding of a workpiece with a grinding wheel that is rotated by the rotating shaft while being held by the tool holder. The tool holder has a main supply hole formed in the axial center and a plurality of branch supply holes that branch off obliquely from the main supply hole toward the circumferential surface of the grinding wheel, and the grinding fluid is sprayed from the plurality of branch supply holes toward the circumferential surface of the grinding wheel.

[0007] Patent Document 5 describes a machine tool including a tool rotating shaft in which a flow passage is formed penetrating the inside of the rotating shaft, and a tool holder provided with a flow passage continuous with the flow passage of the tool rotating shaft. The flow passage of the tool holder is connected to the inner peripheral surface of the attached grinding wheel, and the attached grinding wheel is configured to have holes that communicate from the inner peripheral surface to the outer peripheral surface, and coolant is injected from one end of the tool rotating shaft, passes through the tool holder, then flows from the inner peripheral surface to the outer peripheral surface of the grinding wheel, and is finally released from the outer peripheral surface, whereby the coolant is sprayed from the grinding wheel, which is the tool. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 5-318326 [Patent Document 2] JP 2019-42833 A [Patent Document 3] JP 2020-131325 A [Patent Document 4] Patent No. 6437255 [Patent Document 5] International Publication No. 2012 / 073638 Summary of the Invention [Problem to be solved by the invention]

[0009] However, as described in Patent Documents 1 to 5, when a flow passage extending in the axial direction of a rotating tool is formed and a fluid is ejected from the flow passage to a processing point, the ejection direction of the fluid is affected by, for example, the inertial force accompanying the rotation of the rotating tool. Therefore, when the processing conditions (for example, the rotation speed of the rotating tool) change, the ejection direction of the fluid may also change. In order to make the fluid reach a desired processing point, it is conceivable to design the shape of the flow passage for each set processing condition, but this is not realistic.

[0010] In addition, the relative positions of the fluid outlet and the processing point vary depending on the shape of the rotating tool, such as the diameter of the rotating tool, the length of the rotating tool in the direction of the rotation axis, etc. In this case, in order to make the fluid reach the desired processing point, it is conceivable to design the shape of the flow passage for each shape of the rotating tool, but this is also unrealistic.

[0011] In addition, as the rotary tool is used and wears, the relative position between the fluid outlet and the processing point may change, making it difficult to make the fluid reach the desired processing point in accordance with the relative position between the fluid outlet and the processing point, which changes over time.

[0012] Furthermore, as described in Patent Documents 4 and 5, in the case of a configuration in which a fluid is discharged from the outer surface of the grindstone, depending on the shape of the grindstone, the strength of the grindstone may decrease.

[0013] The present invention has been made in consideration of the above problems, and aims to provide a tool unit and a machine tool that can solve at least one of the above problems and can make a fluid reach a machining point. [Means for solving the problem]

[0014] One aspect of the present invention is A rotating tool that rotates about a rotation axis to machine a workpiece at a machining point; a tool holder for holding the rotary tool and including a flow passage through which a fluid flows; a pump connected to the flow passage and configured to supply the fluid to the flow passage; a pressure adjusting section disposed between the pump and the flow passage and configured to adjust a pressure of the fluid flowing through the flow passage; an information acquisition unit that acquires at least one of shape information related to a shape of the rotating tool or the workpiece, machining condition information related to a machining condition of the rotating tool, and wear information related to a wear amount of the rotating tool; A control unit that controls the pressure adjustment unit based on the information acquired from the information acquisition unit, The flow passage is an axial flow passage extending along the rotation shaft; a branch flow passage branching from the axial flow passage and extending along a direction inclined toward a machining point of the rotary tool with respect to the rotary shaft, an outlet for ejecting the fluid onto the rotary tool or the tool is formed at an end of the branch flow passage opposite to the axial flow passage, The control unit is A tool unit that supplies the fluid ejected from the nozzle to the rotating tool or the workpiece by controlling the pressure adjustment unit to change the pressure of the fluid based on the information acquired from the information acquisition unit. Effect of the Invention

[0015] According to one aspect of the present invention, even if the shape of the rotating tool or the workpiece, the machining conditions of the rotating tool, or the wear amount of the rotating tool changes, the fluid can be supplied to the machining point. Therefore, it is possible to provide a tool unit and a machine tool capable of making the fluid reach the machining point. [Brief description of the drawings]

[0016] [Figure 1] 1 is a conceptual diagram showing the configuration of a threaded grinding wheel and a workpiece according to a first embodiment. FIG. [Diagram 2] 1 is a schematic cross-sectional view showing a configuration of a machine tool according to a first embodiment. [Diagram 3]1 is an axial cross-sectional view of a threaded grinding wheel according to a first embodiment. [Figure 4] 1 is a partially enlarged cross-sectional view showing a threaded grinding wheel, a tool holder, a flow passage, and a nozzle according to a first embodiment. [Diagram 5] FIG. 2 is a front view showing a threaded grinding wheel, a tool holder, a bolt-side branch flow passage, and a nozzle according to the first and second embodiments. [Figure 6] 4 is a graph showing the relationship between the rotation speed of the threaded grinding wheel and the pressure of a fluid in the first embodiment. [Figure 7] 3 is a main flow of the machine tool according to the first embodiment. [Figure 8] FIG. 11 is a front view showing a threaded grinding wheel, a tool holder, a tool holder-side branch flow passage, and a nozzle according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] (Embodiment 1) 1. Processing target The workpiece W to be machined by the machine tool 1 according to this embodiment is any workpiece W machined by a rotary tool, and is not particularly limited to an internal gear, an external gear, a cylindrical member, etc. In this embodiment, an internal gear having a tooth surface on the inner peripheral surface of the workpiece W is adopted as shown in Fig. 1. In the following description, for multiple identical members, only some of the members may be given reference numerals, and the reference numerals may be omitted for the other members.

[0018] 2. Configuration of machine tool 1 The machine tool 1 in this embodiment is appropriately selected depending on the workpiece W to be machined. Furthermore, the machining method executed by the machine tool 1 is not particularly limited, and any machining method such as grinding or cutting can be appropriately selected. In this embodiment, since the workpiece W is an internal gear, an internal gear generating grinding machine is used as the machine tool 1.

[0019] As shown in Fig. 2, the machine tool 1 includes a spindle 2, a motor 3, and a tool unit 10. The tool unit 10 includes a threaded grinding wheel 11 (an example of a rotary tool), a tool holder 12, a pump 13, a pressure adjustment unit 14, a control unit 15, and an information acquisition unit 16. However, the detailed structure and shape of the threaded grinding wheel 11 are omitted from Fig. 2.

[0020] 1, a workpiece W is attached to a machine tool 1 so as to be rotatable about a workpiece rotation axis C1 R1 parallel to the vertical direction (Z-axis direction). A predetermined tooth shape is formed in advance on this workpiece W, and the axial direction of the workpiece W is parallel to the Z-axis direction.

[0021] In addition, the machine tool 1 supports a tool holder 12 rotatably around a grindstone rotation axis B1 R2, which is an example of a rotation axis. The tool holder 12 is movable in a direction in which the distance between the workpiece rotation axis C1 and the grindstone rotation axis B1 is adjusted (hereinafter referred to as the X-axis direction), in a direction perpendicular to the grindstone rotation axis B1 (hereinafter referred to as the Y-axis direction), and in a Z-axis direction. A threaded grindstone 11 for grinding the workpiece W is attached to the tip of the tool holder 12. Therefore, by moving the tool holder 12 in the X-axis, Y-axis, and Z-axis directions and rotating it around the grindstone rotation axis B1 R2, the threaded grindstone 11 moves and rotates together with the tool holder 12. However, a detailed shape of the tool holder 12 is omitted in FIG. 1.

[0022] The grinding wheel rotation axis B1 of the tool holder 12 is inclined with respect to the workpiece rotation axis C1, and the two intersect at a shaft angle Σ. In the present embodiment 1, the shaft angle Σ is adjustable, and the threaded grinding wheel 11 during grinding rotates around the grinding wheel rotation axis B1 that intersects with the workpiece rotation axis C1 of the workpiece W at a shaft angle Σ.

[0023] When the object to be machined is an external gear, it is possible to grind the external gear by mounting a grinding wheel gear for grinding external teeth on the tip of the tool holder 12 instead of the threaded grinding wheel 11. When the object to be machined is a cylindrical member, it is possible to grind the cylindrical member by mounting a grinding wheel for grinding cylindrical members on the tip of the tool holder 12 instead of the threaded grinding wheel 11. It is also possible to use a skiving cutter as the rotating tool to machine an internal gear or an external gear.

[0024] The threaded grinding wheel 11 rotates around the grinding wheel rotation axis B1 and the workpiece W rotates around the workpiece rotation axis C1 so that the blade of the threaded grinding wheel 11 meshes with the teeth of the workpiece W. As a result, the threaded grinding wheel 11 grinds the workpiece W at the processing point P. The processing point P is not limited to a so-called point, but is defined as a portion where the threaded grinding wheel 11 and the workpiece W contact each other. For example, the processing point P is a point when the threaded grinding wheel 11 and the workpiece W contact each other at a point, a line when the threaded grinding wheel 11 and the workpiece W contact each other in a linear region, and a surface when the threaded grinding wheel 11 and the workpiece W contact each other on a flat or curved surface.

[0025] When a threaded grinding wheel 11 having the cross-sectional shape shown in Fig. 3 is rotated around a grinding wheel rotation axis B1, the outer peripheral surface of the threaded grinding wheel 11 describes a rotation locus 11a. A diameter D1 of the rotation locus 11a of the outer peripheral surface of a first end 111, which is one axial end of the threaded grinding wheel 11, is smaller than a diameter D2 of the rotation locus 11a of the outer peripheral surface of a second end 112, which is the other axial end. In the rotation locus 11a of the outer peripheral surface of the threaded grinding wheel 11, at least the rotation locus 11a of the outer peripheral surface of the second end 112 has a maximum diameter D2.

[0026] The threaded grinding wheel 11 according to this embodiment has a diameter that decreases from the second end 112 to the first end 111. This causes the threaded grinding wheel 11 to be formed in a cup shape. The threaded grinding wheel 11 may have a region in which the diameter of the rotation locus does not change from the first end 111 to the second end 112. Alternatively, the rotation locus of the outer circumferential surface of the threaded grinding wheel 11 may be cylindrical in shape, in which the diameter of the rotation locus does not change from the first end 111 to the second end 112.

[0027] As shown in FIG. 2, the tool holder 12 has a mounting portion 12a to be attached to the spindle 2 of the machine tool 1, a flange portion 12b provided at one end of the mounting portion 12a with its axis coinciding, a cylindrical portion 12c provided on the opposite side of the flange portion 12b to the mounting portion 12a with its axis coinciding, a grinding wheel mounting portion 12d provided at the tip of the cylindrical portion 12c with its axis coinciding and having a diameter slightly larger than that of the cylindrical portion 12c, and a grinding wheel bolt 12f screwed into the tip of the grinding wheel mounting portion 12d to fix the threaded grinding wheel 11 to the grinding wheel mounting portion 12d.

[0028] The threaded grinding wheel 11 is fitted to the tip side of the grinding wheel mounting portion 12d in the direction of the grinding wheel rotation axis B1, and the threaded grinding wheel 11 can be attached to the grinding wheel mounting portion 12d by screwing a grinding wheel bolt 12f into a female threaded hole 12e formed in the axis of the grinding wheel mounting portion 12d.

[0029] A tool holder-side axial flow passage 20 (one example of an axial flow passage) is formed in the axial center of the tool holder 12, penetrating the tool holder 12 in the direction of the grinding wheel rotation axis B1. Furthermore, a bolt-side axial flow passage 30 (one example of an axial flow passage) is formed in the axial center of the grinding wheel bolt 12f, with a length from the end screwed into the grinding wheel attachment part 12d to the head part 12g. The end of the bolt-side axial flow passage 30 screwed into the grinding wheel attachment part 12d communicates with the tool holder-side axial flow passage 20. A fluid such as a coolant flows through the tool holder-side axial flow passage 20 and the bolt-side axial flow passage 30. The fluid has the function of cooling the threaded grinding wheel 11 and the workpiece W, and also has the function of washing away shavings from the workpiece W ground by the threaded grinding wheel 11.

[0030] A plurality of tool holder side branch flow passages 21 (an example of a branch flow passage) branching off from the tool holder side axial flow passage 20 and extending in a direction inclined toward the machining point P of the threaded grinding wheel 11 with respect to the grinding wheel rotation axis B1 are formed in the grinding wheel attachment portion 12d on the side of the cylindrical portion 12c in the direction of the grinding wheel rotation axis B1. A tool holder side outlet 22 (an example of an outlet) for ejecting fluid onto the threaded grinding wheel 11 or the workpiece W is opened at the end of the tool holder side branch flow passage 21 opposite to the tool holder side axial flow passage 20.

[0031] A plurality of bolt-side branched flow passages 31 (an example of a branched flow passage) are formed in the head 12g of the grinding wheel bolt 12f, branching off from the bolt-side axial flow passage 30 and extending in a direction inclined toward the processing point P of the threaded grinding wheel 11 with respect to the grinding wheel rotation axis B1. A bolt-side ejection port 32 (an example of an ejection port) for ejecting fluid onto the threaded grinding wheel 11 or the workpiece W is opened at the end of the bolt-side branched flow passage 31 opposite the bolt-side axial flow passage 30.

[0032] 4, the acute angle θ of the angle between the grindstone rotation axis B1 direction and the tool holder side branch flow passage 21 is set to be the same as the acute angle φ of the angle between the grindstone rotation axis B1 direction and the bolt side branch flow passage 31. However, the term "same" includes the case where they are the same, and also includes the case where they are not the same but can be recognized as being substantially the same. However, the acute angle θ and the acute angle φ may be different.

[0033] In the direction of the grinding wheel rotation axis B1, it is preferable that the distance L from the branch point of the tool holder side branch flow passage 21, located on one side of the threaded grinding wheel 11 (the right side in FIG. 4), with the tool holder side axial flow passage 20 to the threaded grinding wheel 11 and the distance M from the branch point of the bolt side branch flow passage 31, located on the other side of the threaded grinding wheel 11 (the left side in FIG. 4), with the bolt side axial flow passage 30 to the threaded grinding wheel 11 be set to be the same. This is because the fluid can be supplied evenly to the threaded grinding wheel 11 or the workpiece W in the direction of the grinding wheel rotation axis B1.

[0034] 5, the bolt side branch flow passages 31 are formed radially from the bolt side shaft flow passage 30. In this embodiment, six bolt side branch flow passages 31 are formed, but the number of bolt side branch flow passages 31 is arbitrary and may be one to five, or seven or more. In this embodiment, the multiple bolt side branch flow passages 31 are arranged at equal intervals in the circumferential direction of the tool holder 12, but this is not limited thereto, and the intervals between adjacent bolt side branch flow passages 31 may be different from each other.

[0035] In this embodiment, the bolt side branch flow passage 31 and the tool holder side branch flow passage 21 are arranged at positions where they overlap when viewed from the direction of the grindstone rotation axis B1.

[0036] 4, the tool holder side branch flow passage 21 includes a small diameter portion 21a located on the tool holder side shaft flow passage 20 side, a large diameter portion 21b located on the opposite side to the tool holder side shaft flow passage 20 and having an inner diameter dimension larger than that of the small diameter portion 21a, and a nozzle fixing portion 21c formed between the small diameter portion 21a and the large diameter portion 21b to fix a nozzle 40 described later. An end of the large diameter portion 21b opposite to the small diameter portion 21a is used as the tool holder side ejection port 22. The inner diameter dimension of the nozzle fixing portion 21c is larger than that of the small diameter portion 21a and smaller than that of the large diameter portion 21b.

[0037] A nozzle 40 is disposed in the tool holder side branch flow passage 21, straddling the nozzle fixing portion 21c and the large diameter portion 21b. The nozzle 40 includes a constricted portion 41 located within the nozzle fixing portion 21c, and an expanded diameter portion 42 located within the large diameter portion 21b. The inner diameter dimension of the constricted portion 41 is set smaller than the inner diameter dimension of the small diameter portion 21a. Moreover, the inner diameter dimension of the expanded diameter portion 42 is set smaller than the inner diameter dimension of the large diameter portion 21b.

[0038] 4, the bolt-side branch flow passage 31 includes a small diameter portion 31a located on the bolt-side shaft flow passage 30 side, a large diameter portion 31b located on the opposite side to the bolt-side shaft flow passage 30 and having an inner diameter dimension larger than that of the small diameter portion 31a, and a nozzle fixing portion 31c formed between the small diameter portion 31a and the large diameter portion 31b to fix the nozzle 40. The end of the large diameter portion 31b opposite to the small diameter portion 31a is the bolt-side ejection port 32. The inner diameter dimension of the nozzle fixing portion 31c is larger than that of the small diameter portion 31a and smaller than that of the large diameter portion 31b.

[0039] 4, in the bolt-side branch flow passage 31, a nozzle 40 is disposed across the nozzle fixing portion 31c and the large diameter portion 31b. The nozzle 40 is disposed across the inside of the small diameter portion 31a and the inside of the large diameter portion 31b. The inner diameter dimension of the narrowed portion 41 of the nozzle 40 is set smaller than the inner diameter dimension of the small diameter portion 31a. Moreover, the inner diameter dimension of the expanded diameter portion 42 is set smaller than the inner diameter dimension of the large diameter portion 31b.

[0040] The inner diameter dimension of the throttle portion 41 of the nozzle 40 arranged in the tool holder side branch flow passage 21 may be the same as the inner diameter dimension of the throttle portion 41 of the nozzle 40 arranged in the bolt side branch flow passage 31. In this case, the fluid can be supplied to the threaded grinding wheel 11 evenly in the direction of the grinding wheel rotation axis B1.

[0041] Furthermore, the inner diameter dimension of the throttle portion 41 of the nozzle 40 arranged in the tool holder side branch flow passage 21 may be different from the inner diameter dimension of the throttle portion 41 of the nozzle 40 arranged in the bolt side branch flow passage 31. In this case, it is possible to appropriately supply fluid to the threaded grinding wheel 11, the diameter of the rotation locus of which changes in the direction of the grinding wheel rotation axis B1.

[0042] The inner diameter dimension of the throttle portion 41 of the plurality of nozzles 40 arranged in the tool holder side branch flow passage 21 may have a plurality of set values. Also, the inner diameter dimension of the throttle portion 41 of the plurality of nozzles 40 arranged in the bolt side branch flow passage 31 may have a plurality of set values. The position where the fluid reaches at the machining point P of the threaded grinding wheel 11 can be made different for each nozzle 40. This makes it possible to respond to, for example, slight changes in the dimensions of the threaded grinding wheel 11 or slight changes in the rotational speed of the threaded grinding wheel 11.

[0043] As shown in Fig. 2, a connecting flow passage 50 is arranged in the machine tool 1. The connecting flow passage 50 communicates with the tool holder side shaft flow passage 20. A pump 13 is connected to the connecting flow passage 50. The pump 13 is not particularly limited, and a pump 13 having a known configuration can be appropriately selected. The pump 13 supplies a fluid to the connecting flow passage 50. A pressure adjustment unit 14 that adjusts the pressure of the fluid is arranged in the connecting flow passage 50 between the pump 13 and the tool holder side shaft flow passage 20. The pressure adjustment unit 14 can be, for example, a known pressure adjustment valve or any other configuration that can adjust the pressure of the fluid.

[0044] The machine tool 1 includes a spindle 2, a tool holder 12, and a motor 3 that rotates the threaded grinding wheel 11 around a grinding wheel rotation axis B1 R2. The structure of the motor 3 is not particularly limited, and any known motor 3 can be appropriately selected.

[0045] The control unit 15 is configured with a well-known microcomputer having a processor, memory, etc., and its peripheral circuits, and may be, for example, a CNC (Computer Numerical Controller) or a PLC (Programmable Logic Controller).

[0046] The information acquiring unit 16 acquires at least one of the following information: shape information relating to the shape of the threaded grinding wheel 11 or the workpiece W, machining condition information relating to the machining conditions of the threaded grinding wheel 11, and wear information relating to the amount of wear of the threaded grinding wheel 11. However, the shape information may include only information relating to the shape of the threaded grinding wheel 11, may include only information relating to the workpiece W, or may include information relating to the shapes of both the threaded grinding wheel 11 and the workpiece W.

[0047] The shape information includes the number of teeth, helix angle, diameter dimensions D1, D2, length dimension of the threaded grinding wheel 11 in the direction of the grinding wheel rotation axis B1, dimensions related to the shape of the blade formed on the threaded grinding wheel 11, number of teeth of the tooth groove of the workpiece W, helix angle, pitch circle diameter, tip circle diameter, root circle diameter, etc. The shape information may be configured to be input by an operator via an input device such as a keyboard or touch panel (not shown). Also, the shape information may be configured to be received from a network (not shown) or a server (not shown).

[0048] The machining condition information is information on the machining conditions of the workpiece W, and includes rotational speed information on the rotational speed of the threaded grinding wheel 11, movement speed information on the movement speed of the threaded grinding wheel 11 in the direction of the grinding wheel rotation axis B1, the cutting depth at the machining point P, etc. The machining condition information may be configured to be input by an operator via an input device such as a keyboard or touch panel (not shown). The machining condition information may also be configured to be received from a network (not shown) or a server (not shown). The information acquisition unit 16 may acquire the rotational speed of the motor 3 from a sensor (not shown) arranged on the motor 3.

[0049] The wear information is information about the amount of wear of the threaded grinding wheel 11, and includes information about the outer dimensions of the threaded grinding wheel 11 and the accumulated use time of the threaded grinding wheel 11. The information acquiring unit 16 may be configured to acquire the outer dimensions of the threaded grinding wheel 11 measured by a sizing device (not shown).

[0050] The control unit 15 controls the pressure adjustment unit 14 based on the information acquired from the information acquisition unit 16, thereby adjusting the pressure of the fluid flowing through the connecting flow passage 50, the tool holder side axial flow passage 20, the bolt side axial flow passage 30, the tool holder side branch flow passage 21, and the bolt side branch flow passage 31.

[0051] 3. Pressure adjustment by the control unit 15 3.1.Rotational Speed ​​of the Threaded Grinding Wheel 11 4 and 5, the fluid ejected from tool holder-side ejection port 22 is ejected in the direction of a resultant vector FC of an ejection vector FA along the extension direction of tool holder-side ejection port 22 and an inertia vector FB generated by the rotation of threaded grinding wheel 11. In order to supply the fluid to machining point P of threaded grinding wheel 11, it is preferable that the resultant vector FC extends in a direction toward the vicinity of machining point P of threaded grinding wheel 11, and it is even more preferable that the resultant vector FC extends accurately toward machining point P of threaded grinding wheel 11.

[0052] When the rotational speed of the threaded grinding wheel 11 changes, the magnitude of the inertia vector FB changes, and this changes the direction of the resultant vector FC. In other words, when the rotational speed of the threaded grinding wheel 11 changes, the ejection direction of the fluid changes, and there is a concern that the fluid may not be able to reach the processing point P of the threaded grinding wheel 11.

[0053] Therefore, in this embodiment, the control unit 15 controls the pressure adjustment unit 14 to change the pressure of the fluid, thereby changing the magnitude of the fluid ejection vector FA in response to changes in the rotational speed of the threaded grinding wheel 11. This makes it possible to suppress changes in the direction of the resultant vector FC. As a result, the fluid can be supplied to the processing point P of the threaded grinding wheel 11.

[0054] When the rotation speed of the threaded grinding wheel 11 increases, the inertia vector FB increases, and the direction of the resultant vector FC changes to approach a direction perpendicular to the grinding wheel rotation axis B1. Therefore, when the rotation speed of the threaded grinding wheel 11 increases, the control unit 15 controls the pressure adjustment unit 14 to reduce the pressure of the fluid. This makes it possible to reduce the pressure of the fluid ejected from the tool holder side nozzle 22 and the bolt side nozzle 32. As a result, even when the rotation speed of the threaded grinding wheel 11 increases, the momentum of the fluid ejected from the tool holder side nozzle 22 and the bolt side nozzle 32 can be prevented from increasing, and therefore the fluid supply position can be prevented from shifting.

[0055] Fig. 6 shows the relationship between the rotational speed (revolutions per minute) of the threaded grinding wheel 11 and the pressure of the fluid. As shown in Fig. 6, the control unit 15 in this embodiment controls the pressure adjustment unit 14 so that the fluid pressure decreases in a curved manner as the rotational speed of the threaded grinding wheel 11 increases. However, the relationship between the rotational speed (revolutions per minute) of the threaded grinding wheel 11 and the pressure of the fluid is not limited to the relationship shown in Fig. 6, and may be configured to change linearly or stepwise, for example, and the pressure of the fluid can be changed according to the change in the rotational speed of the threaded grinding wheel 11 with any relationship.

[0056] On the other hand, when the rotation speed of the threaded grinding wheel 11 decreases, the control unit 15 increases the pressure of the fluid by controlling the pressure adjustment unit 14. This makes it possible to prevent the supply positions of the fluid ejected from the tool holder side ejection port 22 and the bolt side ejection port 32 from shifting.

[0057] 3.2. Shape of the Threaded Grinding Wheel 11 For example, when a threaded grinding wheel 11 with a relatively small diameter is attached to the grinding wheel attachment portion 12d of the tool holder 12, the position of the processing point P of the threaded grinding wheel 11 differs in the radial direction of the threaded grinding wheel 11 from the position when a threaded grinding wheel 11 with a relatively large diameter is attached. In this embodiment, the control unit 15 controls the pressure adjustment unit 14 based on shape information on the shape of the threaded grinding wheel 11 to change the pressure of the fluid, thereby changing the magnitude of the fluid ejection vector FA according to the shape of the threaded grinding wheel 11. This makes it possible to suppress changes in the direction of the resultant vector FC. As a result, the fluid can be supplied to the processing point P of the threaded grinding wheel 11.

[0058] When a threaded grinding wheel 11 with a large diameter is used, the distance between the processing point P of the threaded grinding wheel 11 and the tool holder side outlet 22 and the bolt side outlet 32 ​​becomes large. This may cause the fluid ejected from the tool holder side outlet 22 and the bolt side outlet 32 ​​to be unable to reach the processing point P of the threaded grinding wheel 11. Therefore, when a threaded grinding wheel 11 with a large diameter is used, the control unit 15 according to this embodiment controls the pressure adjustment unit 14 to increase the pressure of the fluid. This makes it possible to increase the reach of the fluid ejected from the tool holder side outlet 22 and the bolt side outlet 32. As a result, even when a threaded grinding wheel 11 with a large diameter is used, the fluid can be made to reach the processing point P of the threaded grinding wheel 11.

[0059] On the other hand, when a threaded grinding wheel 11 with a small diameter is used, the control unit 15 reduces the pressure of the fluid by controlling the pressure adjustment unit 14. This makes it possible to reduce the reach of the fluid ejected from the tool holder side nozzle 22 and the bolt side nozzle 32. As a result, even when a threaded grinding wheel 11 with a small diameter is used, the fluid can be made to reach the processing point P of the threaded grinding wheel 11.

[0060] Furthermore, when a threaded grinding wheel 11 having a large length dimension in the direction of the grinding wheel rotation axis B1 is used, the distance between the processing point P of the threaded grinding wheel 11 and the tool holder side outlet 22 and the bolt side outlet 32 ​​becomes large. This may cause the fluid ejected from the tool holder side outlet 22 and the bolt side outlet 32 ​​to be unable to reach the processing point P of the threaded grinding wheel 11. Therefore, when a threaded grinding wheel 11 having a large diameter is used, the control unit 15 according to this embodiment controls the pressure adjustment unit 14 to increase the pressure of the fluid. This makes it possible to increase the reach of the fluid ejected from the tool holder side outlet 22 and the bolt side outlet 32. As a result, even when a threaded grinding wheel 11 having a large diameter is used, the fluid can be made to reach the processing point P of the threaded grinding wheel 11.

[0061] On the other hand, when a threaded grinding wheel 11 having a small length dimension in the direction of the grinding wheel rotation axis B1 is used, the control unit 15 controls the pressure adjustment unit 14 to reduce the pressure of the fluid. This makes it possible to reduce the reach of the fluid ejected from the tool holder side nozzle 22 and the bolt side nozzle 32. As a result, even when a threaded grinding wheel 11 having a small length dimension in the direction of the grinding wheel rotation axis B1 is used, the fluid can be made to reach the processing point P of the threaded grinding wheel 11.

[0062] 3.3. Wear amount of the threaded grinding wheel 11 When the threaded grinding wheel 11 wears due to continuous use, the diameter dimension of the threaded grinding wheel 11 decreases over time. In this embodiment, the control unit 15 controls the pressure adjustment unit 14 based on wear information related to the amount of wear of the threaded grinding wheel 11 to change the pressure of the fluid, thereby changing the magnitude of the fluid ejection vector FA according to the amount of wear of the threaded grinding wheel 11. This makes it possible to suppress changes in the direction of the resultant vector FC, and as a result, the fluid can be supplied to the processing point P of the threaded grinding wheel 11.

[0063] More specifically, as the wear amount of the threaded grinding wheel 11 increases, the diameter of the threaded grinding wheel 11 decreases. In this case, the control unit 15 controls the pressure adjustment unit 14 to reduce the fluid pressure. This makes it possible to reduce the reach of the fluid ejected from the tool holder side nozzle 22 and the bolt side nozzle 32. As a result, even when the wear amount of the threaded grinding wheel increases, the fluid can be made to reach the processing point P of the threaded grinding wheel 11.

[0064] 4. Operation of this mode The operation of the machine tool 1 according to this embodiment will be described with reference to Fig. 7. Fig. 7 shows a main flow relating to the operation of the machine tool 1 according to this embodiment. When the machine tool 1 is started and a machining program is started (S1), the information acquisition unit 16 acquires shape information relating to the shape of the threaded grinding wheel 11 or the workpiece W (S2), and acquires machining condition information (S3). However, the order of S2 and S3 is not particularly limited. The control unit 15 acquires the shape information and the machining condition information, and sets the supply pressure of the fluid by controlling the pressure adjustment unit 14 based on the shape information and the machining condition information (S4).

[0065] Next, machining is performed on the workpiece W (S5). The information acquisition unit 16 acquires wear information on the amount of wear of the threaded grinding wheel 11 from a sizing device (not shown) or the like (S6). The control unit 15 acquires the wear information and corrects the supply pressure of the fluid by controlling the pressure adjustment unit 14 based on the wear information (S7).

[0066] Control unit 15 determines whether or not an instruction to stop machining has been acquired for machine tool 1 (S8). If an instruction to stop machining has not been acquired (S8: N), the processes of S6 to S8 are repeated.

[0067] When an instruction to stop machining is acquired (S8: Y), the machining program is stopped (S9). With the above, the operation of the machine tool 1 is terminated.

[0068] 5. Effects of this Form Next, the operation and effect of this embodiment will be described. According to this embodiment, the information acquisition unit 16 acquires at least one of shape information related to the shape of the threaded grinding wheel 11 or the workpiece W, processing condition information related to the processing conditions of the threaded grinding wheel 11, and wear information related to the amount of wear of the threaded grinding wheel 11. The control unit 15 controls the pressure adjustment unit 14 based on the information acquired from the information acquisition unit 16 to change the pressure of the fluid, thereby supplying the fluid ejected from the tool holder side ejection port 22 and the bolt side ejection port 32 to the threaded grinding wheel 11 or the workpiece W. This makes it possible to supply the fluid to the processing point P of the threaded grinding wheel 11 even if the shape of the threaded grinding wheel 11, the processing conditions of the threaded grinding wheel 11, or the amount of wear of the threaded grinding wheel 11 changes.

[0069] Furthermore, in the machine tool 1 according to this embodiment, in the direction of the grinding wheel rotation axis B1, the bolt-side branched flow passage 31 and the bolt-side outlet 32 ​​are arranged on the grinding wheel bolt 12f side of the threaded grinding wheel 11, and the tool holder-side branched flow passage 21 and the tool holder-side outlet 22 are arranged on the tool holder 12 side of the threaded grinding wheel 11. This allows fluid to be supplied to the threaded grinding wheel 11 or the workpiece W from both sides in the direction of the grinding wheel rotation axis B1, making it easier for the fluid to reach the processing point P of the threaded grinding wheel 11.

[0070] According to this embodiment, the acute angle φ between the extension direction of the bolt side branch flow passage 31 and the direction of the grindstone rotation axis B1 is set to be the same as the acute angle θ between the extension direction of the tool holder side branch flow passage 21 and the direction of the grindstone rotation axis B1. This allows the fluid to be supplied to the threaded grindstone 11 or the workpiece W evenly in the direction of the grindstone rotation axis B1.

[0071] According to this embodiment, a nozzle 40 is disposed in the tool holder side branch flow passage 21 and the bolt side branch flow passage 31, and the nozzle 40 has a throttle portion 41 with an inner diameter dimension smaller than the inner diameter dimensions of the tool holder side branch flow passage 21 and the bolt side branch flow passage 31. According to this embodiment, by changing the inner diameter dimension of the throttle portion 41, the amount of fluid supplied to the threaded grinding wheel 11 can be easily changed.

[0072] When machining the inner surface of a workpiece W with a threaded grinding wheel 11 as in this embodiment, there is a concern that the workpiece W located outside the threaded grinding wheel 11 may become an obstacle, making it difficult for the fluid to reach the machining point P of the threaded grinding wheel 11. According to this embodiment, the fluid is ejected from the tool holder 12 that holds the threaded grinding wheel 11 located on the inner peripheral side of the workpiece W, so that it is possible to prevent the workpiece W from becoming an obstacle to the fluid. As a result, the fluid can be easily made to reach the machining point P of the threaded grinding wheel 11.

[0073] Furthermore, in the case of grinding using the threaded grinding wheel 11, the contact area between the rotating tool and the workpiece W is larger than in cutting, and therefore a larger amount of fluid is required. Therefore, it is highly necessary to ensure that the fluid reaches the processing point P. This embodiment is particularly effective when the rotating tool is applied to the threaded grinding wheel 11.

[0074] According to this embodiment, the machining condition information includes rotational speed information regarding the rotational speed of the threaded grinding wheel 11, and the control unit 15 acquires the machining condition information regarding the machining conditions of the threaded grinding wheel 11, and based on the rotational speed information of the machining condition information, controls the pressure adjustment unit 14 to reduce the fluid pressure as the rotational speed increases.

[0075] When the rotation speed of the threaded grinding wheel 11 increases, the inertial force acting on the fluid ejected from the tool holder side nozzle 22 and the bolt side nozzle 32 also increases. As a result, the reach of the fluid ejected from the tool holder side nozzle 22 and the bolt side nozzle 32 may become longer than when the rotation speed of the threaded grinding wheel 11 is low. According to this embodiment, the pressure of the fluid decreases as the rotation speed of the threaded grinding wheel 11 increases. This makes it possible to suppress changes in the reach of the fluid ejected from the tool holder side nozzle 22 and the bolt side nozzle 32 even when the rotation speed of the threaded grinding wheel 11 increases. As a result, the fluid can reach the processing point P.

[0076] According to this embodiment, the control unit 15 acquires wear information, and based on the wear information, controls the pressure adjusting unit 14 to reduce the fluid pressure as the amount of wear increases.

[0077] As the wear amount of the threaded grinding wheel 11 increases, the outer dimensions of the threaded grinding wheel 11 decrease. As a result, the processing point P of the threaded grinding wheel 11 becomes relatively closer to the tool holder side outlet 22 and the bolt side outlet 32. In this embodiment, the greater the wear amount of the threaded grinding wheel 11, the smaller the fluid pressure becomes. This makes it possible to reduce the reach of the fluid ejected from the tool holder side outlet 22 and the bolt side outlet 32, allowing the fluid to reach the processing point P of the threaded grinding wheel 11.

[0078] (Embodiment 2) Next, the second embodiment will be described with reference to Fig. 5 and Fig. 8. Fig. 8 shows the tool holder side branch flow passage 21 and the nozzle 40 arranged in the tool holder side branch flow passage 21. With reference to Fig. 5 and Fig. 8 together, it can be seen that the bolt side branch flow passage 31 and the tool holder side branch flow passage 21 are arranged at positions shifted in the grindstone rotation axis B1 direction. In other words, the tool holder side branch flow passage 21 is arranged at a position between the adjacent bolt side branch flow passages 31 as viewed from the grindstone rotation axis B1 direction. In this embodiment, the tool holder side branch flow passage 21 is arranged at a midpoint between the adjacent bolt side branch flow passages 31 as viewed from the grindstone rotation axis direction. However, the tool holder side branch flow passage 21 may be arranged at a position shifted from the midpoint between the adjacent bolt side branch flow passages 31 as viewed from the grindstone rotation axis B1 direction.

[0079] When viewed from the direction of the grinding wheel rotation axis B1, if the bolt-side outlet 32 ​​arranged on one side of the processing point P of the threaded grinding wheel 11 and the tool holder outlet arranged on the other side are arranged at positions overlapping with each other in the direction of the grinding wheel rotation axis B1, there is a risk that chips generated at the processing point P during processing will be retained at the processing point P due to the fluid simultaneously ejected from both sides of the processing point P. According to this embodiment, the timing at which the fluid reaches the processing point P can be shifted on both sides of the processing point P. This allows the chips generated during processing to be efficiently removed from the processing point P. In addition, the fluid is supplied intensively to the grooves of the same threaded grinding wheel 11, and the amount of wear can be prevented from varying for each groove.

[0080] In addition, among the symbols used in the second and subsequent embodiments, the same symbols as those used in the previous embodiments represent the same components, etc. as those in the previous embodiments, unless otherwise specified.

[0081] The present invention is not limited to the above-described embodiments, and can be applied to various embodiments without departing from the gist of the present invention.

[0082] (1) The rotating tool that rotates around the rotation axis to machine the workpiece W at the machining point P is not limited to the threaded grinding wheel 11, and any rotating tool can be appropriately selected, such as a gear-shaped grinding wheel, a cylindrical grinding wheel, a skiving cutter, etc. In addition, the rotating tool is not limited to inner peripheral machining, and can also be applied to outer peripheral machining.

[0083] (2) The nozzle 40 may be omitted, and the fluid may be ejected from the tool holder side ejection port 22 or the bolt side ejection port 32.

[0084] (3) The tool holder 12 according to this embodiment has a structure adapted to the ATC mechanism of a machining center, but is not limited to this and may have a structure adapted to the wheel spindle of a grinding machine.

[0085] (4) The pressure adjusting unit 14 according to this embodiment may be configured so that the opening amount of the throttling portion 41 of the nozzle 40 can be adjusted by an actuator or the like, and the pressure is adjusted by the control unit 15. [Explanation of symbols]

[0086] 1: machine tool, 3: motor, 10: tool unit, 11: threaded grinding wheel, 11a: rotation trajectory, 12: tool holder, 13: pump, 14: pressure adjustment section, 15: control section, 16: information acquisition section, 20: tool holder side axial flow passage, 21: tool holder side branch flow passage, 22: tool holder side nozzle, 30: bolt side axial flow passage, 31: bolt side branch flow passage, 32: bolt side nozzle, 40: nozzle, 41: throttle section, 50: connection flow passage, B1: grinding wheel rotation axis, P: machining point, W: workpiece

Claims

1. A rotating tool that rotates about a rotation axis to machine a workpiece at a machining point; a tool holder for holding the rotary tool and including a flow passage through which a fluid flows; a pump connected to the flow passage and configured to supply the fluid to the flow passage; a pressure adjusting section disposed between the pump and the flow passage and configured to adjust a pressure of the fluid flowing through the flow passage; an information acquisition unit that acquires at least one of shape information related to a shape of the rotating tool or the workpiece, machining condition information related to a machining condition of the rotating tool, and wear information related to a wear amount of the rotating tool; A control unit that controls the pressure adjustment unit based on the information acquired from the information acquisition unit, The flow passage is an axial flow passage extending along the rotation shaft; a branch flow passage branching from the axial flow passage and extending along a direction inclined toward a machining point of the rotary tool with respect to the rotary shaft, an ejection port for ejecting the fluid onto the rotating tool or the workpiece is formed at an end of the branch flow passage opposite to the axial flow passage, The control unit is A tool unit that supplies the fluid ejected from the nozzle to the rotating tool or the workpiece by controlling the pressure adjustment unit to change the pressure of the fluid based on the information acquired from the information acquisition unit.

2. The tool unit according to claim 1 , wherein the branch flow passage and the ejection port are disposed on both sides of the machining point of the rotating tool in the rotation axis direction.

3. 3. The tool unit according to claim 2, wherein, in the rotation axis direction, an acute angle of an angle of the branch flow passage arranged on one side of the processing point of the rotating tool with respect to the rotation axis is equal to an acute angle of an angle of the branch flow passage arranged on the other side of the processing point of the rotating tool with respect to the rotation axis.

4. 4. The tool unit according to claim 3, wherein, in the rotation axis direction, a distance from a branch point of the branch flow passage, arranged on one side of the rotating tool, with the axial flow passage, to the rotating tool is the same as a distance from a branch point of the branch flow passage, arranged on the other side of the rotating tool, with the axial flow passage, to the rotating tool.

5. 3. The tool unit according to claim 2, wherein an acute angle of an angle of the branch flow passage arranged on one side of the processing point of the rotating tool with respect to the rotation axis is different from an acute angle of an angle of the branch flow passage arranged on the other side of the processing point of the rotating tool with respect to the rotation axis in the rotation axis direction.

6. the tool holder includes a plurality of branch flow passages and a plurality of ejection ports arranged at predetermined intervals along a circumferential direction, 3. The tool unit according to claim 2, wherein, as viewed from the rotation axis direction, the nozzle arranged on one side of the machining point of the rotating tool and the nozzle arranged on the other side are positioned at positions offset from each other in the rotation axis direction.

7. A nozzle is disposed in the branch flow passage, The tool unit according to claim 1 , wherein the nozzle has a restriction having an inner diameter smaller than an inner diameter of the branch flow passage.

8. the tool holder includes a plurality of the branch flow passages and the ejection ports arranged at predetermined intervals in a circumferential direction, The tool unit according to claim 7 , wherein the inner diameter dimensions of the throttle portions of the plurality of nozzles arranged in the plurality of branch flow passages are different from each other.

9. The tool unit according to claim 1 , wherein the rotating tool is used to machine an inner peripheral surface of the workpiece.

10. 2. The tool unit according to claim 1, wherein the rotating tool is a threaded grinding wheel that rotates synchronously with the workpiece, which is a gear, to grind the workpiece.

11. the machining condition information includes rotational speed information regarding a rotational speed of the rotating tool, The control unit is Acquire the machining condition information regarding the machining conditions of the rotary tool; The tool unit according to claim 1 , further comprising: a control for controlling the pressure adjusting unit to reduce the pressure of the fluid as the rotational speed increases based on the rotational speed information of the machining condition information.

12. The control unit is Acquire the wear information; The tool unit according to claim 1 , further comprising: a pressure adjusting unit configured to adjust the pressure of the fluid so as to decrease the pressure of the fluid as the amount of wear increases based on the wear information.

13. A machine tool comprising the tool unit according to any one of claims 1 to 12.

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