Machine tool, filter and filter holder

Abstract

To enable a filter to be held in a tool holder, even when using the tool holder with versatility.SOLUTION: A tool is attached to a machine tool through a tool attachment tool, using a tool holder with versatility having a coolant space into which high-pressure coolant flows therein. A filter is attached to the tool through a filter holder and rotates in the coolant space of the tool holder together with the tool. For the tool, a tool with versatility can be utilized. It is enough that the filter can be arranged in the coolant space of the tool holder, which makes it unnecessary to specially design the filter so that the filter fits to the tool holder. The filter may be constituted of a cylindrical sintered metal comprising a coolant outflow passage at a center part thereof. The filter holder may be threadably-jointed to the filter and also may be connected to the tool thorough an O ring.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a machine tool including a tool holder, a tool, and a filter. The present disclosure relates to a tool holder for assembling the tool and filter to the machine tool. The present disclosure also relates to a filter for use with the tool holder and the tool. The present disclosure further relates to a tool for use with the tool holder and the filter. Additionally, the present disclosure also relates to a filter holder for assembling the filter and the tool. [Background technology]

[0002] It is known that a machine tool uses a tool holder that rotates a tool in response to the rotation of a machining center. It is also known that a coolant passage is formed in the tool and coolant is supplied to the coolant passage. It is also known that a filter is used to remove foreign matter from the coolant supplied to the coolant passage of the tool.

[0003] The tool holder described in Patent Document 1 transmits the rotation of the machining center to the tool to rotate it. A coolant space through which coolant passes is provided inside the tool holder, and a filter is disposed in this coolant space. Patent Document 2 also describes a filter disposed on the tool fixed to the tool holder.

[0004] However, the tool holder of Patent Document 1 has a special structure for fixing and holding the filter inside the tool holder. Therefore, the tool holder needs to be specially designed to fit the filter. Furthermore, the tool holder needs to be disassembled to inspect or clean the filter fixed inside, making filter maintenance cumbersome. Similarly, the tool of Patent Document 2 also has a special structure for fixing and holding the filter. Therefore, the tool needs to be specially designed to fit the filter. Furthermore, because the filter is attached to the tool, it is difficult to create a structure for fixing the filter, especially for small-diameter tools. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2017-030110 [Patent Document 2] Utility Model Application Publication No. 5-37442 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a machine tool that can hold a filter in a tool holder using a general-purpose tool holder, without using a tool holder with a special structure for fixing and holding a filter as a machine tool. Another object of the present disclosure is to provide a tool holder that fixes a general-purpose tool and holds a filter in the internal coolant space. Yet another object of the present disclosure is to provide a filter that can be used with a general-purpose tool holder and a general-purpose tool and removes foreign matter from the coolant space within the tool holder. Another object of the present disclosure is to provide a tool that can be attached to the general-purpose tool holder and that can hold a filter in the coolant space within the tool holder. Yet another object of the present disclosure is to provide a filter holder that assembles a filter and a tool so that the filter can be held in the coolant space of the tool holder. [Means for solving the problem]

[0007] A machine tool (100) of the present disclosure includes a tool holder (120) that is assembled to a machining center (110), rotates about the tool holder central axis in response to the rotation of the machining center, and has a coolant space (127) therein into which high-pressure coolant flows; a tool (130) that is attached to the tool holder via a tool mounting fixture (140), rotates integrally with the tool holder about the tool central axis, and has a coolant passage (134) therein, the coolant inlet of which opens into the coolant space of the tool holder and the coolant outlet of which opens at a machining site; and a filter (180) that is arranged in the coolant space of the tool holder, is assembled to the tool via a filter holder (170), rotates together with the tool about the filter central axis, and removes foreign matter from the coolant flowing from the coolant space toward the coolant inlet.

[0008] In the machine tool of the present disclosure, the tool holder central axis, the tool central axis, and the filter central axis are coaxially arranged. In the machine tool of the present disclosure, the rotation of the tool holder is transmitted to the tool via the tool fixture, and the rotation of the tool is transmitted to the filter via the filter holder. Therefore, the filter is simply attached to the tool by the filter holder, is held in the coolant space of the tool holder, and rotates at the same rotation speed as the coolant space. Even if a versatile tool holder or tool is used, the filter can be held in the coolant space of the tool holder.

[0009] The tool holder disclosed herein is a tool holder that is assembled to a machining center, rotates about its central axis in response to the rotation of the machining center, and has a coolant space into which high-pressure coolant flows. A tool having an internal coolant passage, the coolant inlet of which opens into the coolant space of the tool holder and the coolant outlet of which opens into the machining site, is attached to the tool holder via a tool fixture, and the tool is rotated integrally with the tool holder about its central axis. The tool holder disclosed herein also has a filter that removes foreign matter from the coolant flowing from the coolant space toward the coolant inlet, assembled to the tool via a filter holder, and the filter is rotated about its central axis to hold it in the coolant space of the tool holder. The tool holder disclosed herein has a central axis that is coaxial with the tool and filter central axes.

[0010] The tool holder of the present disclosure has an internal coolant space and only transmits rotation to the tool, eliminating the need for a special configuration for holding a filter. In other words, a general-purpose tool holder can be used without a special design for holding a filter. Furthermore, the tool attached to the tool holder via the tool fixture can also be a general-purpose tool. Furthermore, the filter is assembled to the tool using a filter holder, allowing the tool to hold the filter. Furthermore, the filter need not be specially designed to fit the tool holder, as long as it is placed within the coolant space of the tool holder. In this way, assembling the filter to the tool using the filter holder allows the tool holder to be general-purpose, and the filter does not need to be specially designed to fit the tool holder.

[0011] The filter disclosed herein has a coolant space therein through which high-pressure coolant flows, and is used with a tool holder that rotates about its central axis in response to the rotation of a machining center, and a tool that rotates about its central axis in response to the rotation of the tool holder and has a coolant passage therein. The filter disclosed herein is disposed in the coolant space of the tool holder and removes foreign matter from the coolant that flows from the coolant space toward the coolant passage of the tool. The filter disclosed herein is also assembled to the tool via a filter holder, and rotates about its central axis within the coolant space of the tool holder in response to the rotation of the tool. The filter central axis of the filter disclosed herein is positioned coaxially with the central axes of the tool holder and the tool.

[0012] The filter of the present disclosure simply needs to be able to be placed within the coolant space of the tool holder. That is, it does not need to be specially designed for the tool holder. Furthermore, the filter of the present disclosure only needs to be assembled to the tool using a filter holder. Once assembled to the tool, the filter can rotate with the tool within the coolant space.

[0013] The tool disclosed herein is used with a tool holder having a coolant space therein into which high-pressure coolant flows and which rotates about the tool holder central axis in response to the rotation of a machining center, and a filter disposed in the coolant space of the tool holder to remove foreign matter from the coolant. The tool also includes a coolant passage formed therein with a coolant inlet and a coolant outlet at both ends. The tool is attached to the tool holder via a tool fixture and rotates about the tool central axis in response to the rotation of the tool holder. The tool is connected to a filter via a filter holder, and the rotation of the tool is transmitted to the filter, causing the filter to rotate about the filter central axis, and coolant that has passed through the filter flows into the coolant passage through the coolant inlet. The tool has a tool central axis that is coaxial with the tool holder central axis and the filter central axis.

[0014] The tool of the present disclosure can be attached to a tool holder via a tool fixture, allowing the use of a general-purpose tool. Furthermore, the tool of the present disclosure connects to a filter using a filter holder, and holds the filter within the coolant space of the tool holder. That is, even when used with a general-purpose tool holder that only has a coolant space, the tool of the present disclosure can hold the filter within the coolant space. Furthermore, the tool of the present disclosure allows the filter to rotate within the coolant space via the filter holder.

[0015] The filter holder disclosed herein is used with a tool holder having a coolant space therein into which high-pressure coolant flows and which rotates about the tool holder central axis in response to the rotation of a machining center, a tool that rotates about the tool central axis in response to the rotation of the tool holder and has a coolant passage therein, and a filter disposed in the coolant space of the tool holder to remove foreign matter from the coolant supplied to the tool, and assembles the tool and the filter. The filter holder disclosed herein is assembled to the tool so that the coolant outlet portion of the filter faces the coolant inlet portion of the tool, allowing the coolant to flow from the filter outlet portion to the tool inlet portion, holding the filter within the coolant space of the tool holder, and transmitting the rotation of the tool to the filter to rotate the filter about the filter central axis. The filter holder disclosed herein is arranged so that the tool central axis and the filter central axis are coaxial with the tool holder central axis.

[0016] In the filter holder of the present disclosure, the filter is attached to the tool so that the coolant outlet of the filter faces the coolant inlet of the tool, and the coolant flows from the outlet of the filter to the inlet of the tool. By using the filter holder of the present disclosure, the filter can be held in the coolant space of the tool holder, and the rotation of the tool can be transmitted to the filter. [Brief explanation of the drawings]

[0017] [Figure 1]FIG. 1 is a front view showing a machine tool, with a part in cross section. [Figure 2] FIG. 2 is a front view, partly in section, showing a tool attached to a tool holder via a tool attachment fixture. [Figure 3] FIG. 3 is a front view showing the tool fixture, the tool, the filter holder, and the filter. [Figure 4] FIG. 4 is a cross-sectional view showing the tool fixture and the tool. [Figure 5] FIG. 5 is a cross-sectional view showing the position of the tool, the filter holder and the filter. [Figure 6] Figure 6 is a circuit diagram of the coolant. [Figure 7] FIG. 7 is a front view of the tool. [Figure 8] 8 is a cross-sectional view of the tool holder and tool shown in FIG. 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] The machine tool 100, filter 180, tool 130, and filter holder 170 of the present disclosure will be described below with reference to the drawings. FIG. 1 is a front view of the machine tool 100, showing a portion of a machining center 110. A tool holder 120 is attached to the machining center 110. Specifically, the pull stud 121 of the tool holder 120 is retracted into the machining center 110, thereby engaging the tapered shank portion 122 with a similarly tapered engaging portion of the machining center 110. More specifically, the pull stud 121 is maintained in a retracted state by a leaf spring (not shown). When the tool holder 120 is to be removed from the machining center 110, the pull stud 121 is removed against the biasing force of the leaf spring.

[0019] As shown in Figures 2 and 8, the pull stud 121 is formed at the end of the tool holder 120 by threading a pull stud bolt 1210 into the shank portion 122. Figure 2 is a front view, partially in cross section, of the tool holder 120, the tool fixture 140, and the tool 130. Figure 8 is a cross-sectional view of Figure 2, illustrating the internal structure of the tool fixture 140, the filter 180 disposed within the tool holder 120, and the filter holder 170.

[0020] The tool holder 120 has a pull stud 121 and a tapered shank portion 122 formed from the inside of the machining center 110. Next, an annular flange portion 124 is formed, followed by a cylindrical protrusion portion 125. A threaded portion 126 into which a tool fixture 140 screws is formed on the outer periphery of the tool holder 120 at the position farthest from the machining center 110.

[0021] Inside tool holder 120, a coolant passage is formed coaxially with tool holder central axis 123, from pull stud 121 to threaded portion 126. A coolant space into which coolant flows is formed around tool holder central axis 123 of tool holder 120. This coolant space 127 is also formed by cylindrical protrusion 125.

[0022] The coolant space 127 has a circular cross section. The inner diameter of the coolant space 127 varies depending on the tool 130 to be attached to the tool holder 120. Specifically, it varies depending on the size of the tool fixture 140 that holds the tool 130. For a small-diameter tool 130, the inner diameter of the coolant space 127 is approximately 10 millimeters. The tool holder 120 rotates around the tool holder central axis 123 in response to the rotation of the machining center 110. The rotation speed of the tool holder 120 depends on the material that the tool 130 is machining, but is approximately 10,000 to 20,000 revolutions per minute.

[0023] A threaded portion 126 is formed on the end of the tool holder 120 opposite the pull stud 121. A tool fixture 140 is attached to this threaded portion 126. A tool 130 is fixed to the tool holder 120 by the tool fixture 140. Therefore, the tool 130 rotates at the same rotation speed as the tool holder 120. Figure 3 is a front view of the tool holder 120 with the tool fixture 140 removed. The tool 130 is held by the tool fixture 140, and a filter 180 is attached to the tool 130 by a filter holder 170.

[0024] As shown in Figures 4 and 8, the tool fixture 140 includes a nut 150 and a collet 160. A nut thread 151 is formed on the inner periphery of the nut 150, on the side facing the tool holder 120. This nut thread 151 is threadedly engaged with the threaded portion 126 of the tool holder 120. A nut engagement portion 152 is formed on the inner periphery of the nut 150, on the side opposite the tool holder 120. A collet engagement groove 162 is formed in the collet 160 at a position corresponding to this nut engagement portion 152. The collet 160 is engaged with the nut 150 via the nut engagement portion 152 and the collet engagement groove 162.

[0025] As shown in FIG. 7, the tool 130 is formed with a cylindrical holding portion 131. A holding hole 161 into which the holding portion 131 of the tool 130 is inserted is formed in the center of the collet 160. The collet 160 has six notches formed on each of its two axial ends, each extending over approximately 80% of its axial length. The axial direction refers to the direction along the tool holder central axis 123 and also the direction along the tool central axis 132 of the tool 130. The collet 160 also has a tapered reduced diameter portion 163 formed on its outer periphery. The inclination angle of the reduced diameter portion 163 corresponds to the collet fixing portion 128 of the tool holder 120 (shown in FIG. 8). In other words, the reduced diameter portion 163 of the collet 160 and the collet fixing portion 128 of the tool holder 120 have the same tapered shape.

[0026] 2 and 8, when the threaded portion 126 of the tool holder 120 is threadedly engaged with the nut thread 151 of the nut 150, the nut 150 and the collet 160 are displaced in the axial direction toward the tool holder 120. In response to this axial displacement of the collet 160, the diameter of the collet 160 is reduced. That is, the spacing between the notches formed on both sides of the collet 160 becomes narrower. This reduction in diameter tightens the holding portion 131 of the tool 130 held in the holding hole 161. As a result, the tool 130 is fixed to the tool holder 120, and the two rotate together.

[0027] A drill 133 is formed at the tip of the tool 130. The tip of the tool 130 is the part on the opposite side of the tool holder 120 from the machining center 110. The drill 133 is an example of the tool 130, and the tool 130 is not limited to the drill 133. For example, an end mill can also be used as the tool 130. The tool 130 may be any tool that rotates around a tool center axis 132 to perform machining.

[0028] The tool 130 has a coolant passage 134 formed along the tool center axis 132. The diameter of this coolant passage 134 is preferably about 10% of the size of the tool 130. For example, if the outer diameter of the drill 133 of the tool 130 is about 8 millimeters, the inner diameter of the coolant passage 134 is preferably about 1 millimeter. In particular, if the tool 130 has a small diameter and the outer diameter of the drill 133 is about 1 millimeter, the inner diameter of the coolant passage 134 is preferably about 0.1 millimeters.

[0029] In the case of a drill 133 of about 8 millimeters, the diameter of the holding portion 131 is about 8 millimeters, which is roughly the same as the diameter of the drill 133. In the case of a drill 133 of about 1 millimeter, the diameter of the holding portion 131 is larger than the diameter of the drill 133, at about 3 to 4 millimeters. Here, even if the diameter of the holding portion 131 of the tool 130 changes slightly, the difference can be absorbed by the holding hole 161 of the collet 160. In other words, the same collet 160 can be used.

[0030] However, as in the above example, when tool 130 having holding portion 131 with a diameter of approximately 8 mm is replaced with tool 130 having holding portion 131 with a diameter of approximately 3 mm, collet 160 is replaced to match the diameter of holding hole 161 to the diameter of holding portion 131. However, the same nut 150 can be used for both collet 160 with holding hole 161 corresponding to approximately 8 mm and collet 160 with holding hole 161 corresponding to approximately 3 mm.

[0031] Therefore, for small diameter tools 130 of about 1 mm to 10 mm, the same nut 150 can be used regardless of the diameter of the drill 133. This means that the same tool holder 120 can be used for small diameter drills 133. However, if the tool 130 becomes larger, both the tool holder 120 and the tool fixture 140 must be replaced to match the tool 130.

[0032] 4 and 8, the coolant passage 134 formed in the tool 130 is separated into two paths and formed in a spiral shape to match the shape of the drill 133. However, the two spiral coolant passages 134 are also formed along the tool central axis 132. However, the coolant passages 134 do not need to be spiral over the entire axial length of the tool 130. For example, it is possible to use a single coolant passage 134 coaxial with the tool central axis 132 in the holding portion 131 of the tool 130, and to arrange two coolant passages 134 spirally only in the area of ​​the drill 133.

[0033] 4, a coolant inlet 135 of the coolant passage 134 opens at one axial end of the holder 131. A coolant outlet 136 of the coolant passage 134 opens at the other axial end of the drill 133. This allows coolant to be supplied directly to the part being machined by the tool 130.

[0034] As shown in Fig. 4, the rear end of the tool 130 has a holding portion 131 that protrudes toward the tool holder 120 from the tool fixture 140. The rear end of the tool 130 is the portion opposite the front end, closer to the machining center 110. The rear end of the tool 130 is inserted into the coolant space 127 of the tool holder 120. The amount of protrusion of the rear end of the tool 130 varies depending on the size of the tool 130. For example, in the case of a tool 130 in which the diameter of the drill 133 is about 1 mm and the diameter of the holding portion 131 is about 3 mm, the amount of protrusion is about 6 mm.

[0035] As shown in Fig. 5, a filter holder 170 is attached to the rear end of the tool 130. Both the filter holder 170 and the filter 180 are cylindrical, and their outer diameters are smaller than the inner diameter of the coolant space 127 of the tool holder 120. Therefore, the filter holder 170 and the filter 180 are arranged without any interference inside the coolant space 127. The outer diameters of the filter holder 170 and the filter 180 are determined according to the diameter of the holding portion 131 of the tool 130. When the diameter of the above-mentioned holding portion 131 is about 3 mm, the outer diameters are about 8 mm.

[0036] The filter holder 170 has a tool holding hole 171 formed therein, the diameter of which is approximately 0.1 to 0.2 millimeters larger than the outer diameter of the holding portion 131 of the tool 130. The tool holding hole 171 is formed in the center of the filter holder 170, giving the filter holder 170 a cylindrical shape. The holding portion 131 is then placed in the tool holding hole 171. An O-ring groove 172 is formed in the tool holding hole 171, and an O-ring 173 is placed in the O-ring groove 172. When the holding portion 131 is placed in the tool holding hole 171, the O-ring 173 undergoes compressive deformation. The O-ring 173 prevents coolant that does not pass through the filter 180 from flowing into the coolant passage 134 of the tool 130. The O-ring 173 is subjected to a differential pressure between the coolant that does not pass through the filter 180 on the right side of the O-ring 173 and the coolant that has passed through the filter on the left side, as shown in FIG. 5 . Since the pressure difference is equal to the pressure loss of the filter 180, sealing is sufficient with the O-ring 173. In addition, the O-ring 173 maintains the state in which the holding portion 131 is held in the tool holding hole 171.

[0037] As described above, the filter 180 has a cylindrical shape and is made of sintered metal. As the coolant passes through the microscopic spaces in the sintered metal, foreign matter contained in the coolant is removed. The diameter of the microscopic spaces is selected depending on the foreign matter to be removed. For example, filters with a diameter of 2 micrometers and 5 micrometers are used. A coolant outlet passage 181 through which the coolant flows out is formed in the center of the filter 180. That is, the coolant outlet passage 181 coincides with the filter central axis 185. The coolant in the coolant space 127 flows in from the outer periphery of the filter 180 and flows toward the coolant outlet passage 181 in the center. The filter 180 has a cylindrical shape due to the coolant outlet passage 181 formed in the center.

[0038] A mounting bracket 182 is fixed to the filter holder 170 side of the filter 180. The mounting bracket 182 includes a filter flange 183 having the same diameter as the outer diameter of the filter 180, and a filter thread portion 184 having a diameter slightly larger than that of the holding portion 131 of the tool 130. The filter thread portion 184 is threadedly engaged with the holder thread portion 174 of the filter holder 170. The filter 180 is fixed to the filter holder 170 by this engagement between the filter thread portion 184 and the holder thread portion 174.

[0039] As described above, the sizes of filter 180 and filter holder 170 are appropriately selected depending on tool 130. More specifically, the sizes of filter 180 and filter holder 170 are determined depending on the size of holding portion 131 of tool 130. Again, in the above example, if the diameter of holding portion 131 of tool 130 is about 3 millimeters and the diameters of filter holder 170 and filter 180 are about 8 millimeters, the axial length of filter 180 is about 10 millimeters. The axial length of filter 180 is about 17 millimeters, of which the length of mounting bracket 182 is about 7 millimeters.

[0040] Machine tool 100 configured as described above is assembled as follows: First, holding portion 131 of tool 130 is inserted into holding hole 161 of collet 160. During this insertion, the rear end of tool 130 is set to protrude a predetermined amount according to holding portion 131 of tool 130. Thereafter, nut engaging portion 152 is engaged with collet engaging groove 162, locking nut 150 and collet 160 in the axial direction.

[0041] Furthermore, filter thread portion 184 formed on the outer periphery of mounting bracket 182 of filter 180 is screwed into holder thread portion 174 formed on the inner periphery of filter holder 170. This screwing unites filter 180 and filter holder 170 together. In this state, the rear end of holding portion 131 of tool 130 protruding from tool fixture 140 is inserted into tool holding hole 171 of filter holder 170. During this fitting, O-ring 173 is compressively deformed.

[0042] The filter 180, filter holder 170, tool fixture 140, and tool 130, which are assembled together as described above, are in the state shown in Figure 3. The filter central axis 185 and the tool central axis 132 are aligned. In this state, the filter holder 170 holds the coolant outlet passage 181 of the filter 180 and the coolant inlet 135 of the tool 130 so that they face each other (see Figure 5).

[0043] Next, nut thread 151 formed on the inner periphery of nut 150 is threadedly engaged with threaded portion 126 formed on the outer periphery of tool holder 120. This threading causes the tapered shape of collet fixing portion 128 of tool holder 120 to press against reduced diameter portion 163 of collet 160, which also has a tapered shape. This pressing narrows the notch in collet 160, and fixes holding portion 131 of tool 130 in holding hole 161 of collet 160. In this way, tool 130 and tool fixture 140 are integrated together.

[0044] The state in which this tool fixture 140 is screwed onto the tool holder 120 is shown in Figure 2. The filter central axis 185 and the tool holder central axis 123 are aligned. In the state shown in Figure 2, the filter 180 and filter holder 170 are disposed within the coolant space 127 of the tool holder 120. As described above, neither the filter 180 nor the filter holder 170 interfere with the tool holder 120. Next, the tool holder 120 in the state shown in Figure 2 is assembled into the machining center 110 to achieve the state shown in Figure 1. The center of rotation of the machining center 110 is aligned with the tool holder central axis 123, the filter central axis 185, and the tool central axis 132.

[0045] Next, the flow of coolant will be explained using Figure 6. Coolant is supplied to the machining area of ​​the tool 130, i.e., the machining area of ​​the workpiece 200, from two locations. One is a first supply from coolant passage 134 of the tool 130, which is supplied directly to the machining area from coolant outlet 136. The other is a second supply from outside the tool 130, which is supplied to the periphery of the machining area. The coolant supplied to the machining area via these two systems is received by machining area tank 201.

[0046] The coolant accumulated in the machining section tank 201 is transported to the intermediate tank 202 by the first pump 210. Specifically, it is transported to a first filter 220 arranged in the intermediate tank 202. The first filter 220 removes foreign matter contained in the coolant. The foreign matter is chips generated during cutting, etc. If the amount of coolant transported by the first pump 210 exceeds the filtering capacity of the first filter 220, the coolant is returned to the machining section tank 201 via a first drain passage 230. A coolant cooler (not shown) is arranged in the intermediate tank 202. The coolant, which has risen in temperature due to the heat during cutting, is cooled by this coolant cooler.

[0047] The coolant cooled by the coolant cooler is transported to the clean tank 203 by the second pump 211. Specifically, this coolant is also transported to the second filter 221 disposed in the clean tank 203. The second filter 221 removes foreign matter that could not be removed by the first filter 220. That is, the first filter 220 removes large foreign matter, and the second filter 221 removes small foreign matter.

[0048] The transport volume of the second pump 211 is constant, but that of the first pump 210 varies depending on the amount of coolant supplied to the machining tank 201. When the transport volume of the first pump 210 exceeds the transport volume of the second pump 211, the coolant that cannot be stored in the intermediate tank 202 is returned to the machining tank 201 through the second drain passage 231. The same is true for the clean tank 203; the coolant that cannot be stored in the clean tank 203 is returned to the intermediate tank 202 through the third drain passage 232. By returning the coolant to the intermediate tank 202 through the third drain passage 232, it is possible to recirculate the coolant through the second filter 221. This increases the rate at which foreign matter is removed from the coolant.

[0049] A third pump 212 is arranged in the clean tank 203, and supplies the coolant in the clean tank 203 to the machine tool 100 via the tool passage 235. This is the first supply mentioned above. The second supply mentioned above uses a fourth pump 213. That is, the coolant in the clean tank 203 is supplied by the fourth pump 213 to the machining site via the external passage 236. A fifth pump 214 is also arranged in the clean tank 203. The fifth pump 214 has the opposite function to the third pump 212, and is used to suck back the coolant remaining in the machine tool 100 into the clean tank 203.

[0050] The second filter 221 described above can remove most foreign matter. For example, if the tool 130 is a drill 133 with a diameter of approximately 8 millimeters and the inner diameter of the coolant passage 134 is approximately 1 millimeter, using only the second filter 221 will hardly cause clogging of the coolant passage 134. However, if the tool 130 has a particularly small diameter, the filtering capacity of the second filter 221 alone may be insufficient. In the case of the tool 130 with a diameter of approximately 1 millimeter and an inner diameter of the coolant passage 134 of approximately 0.1 millimeters described above, clogging of the coolant passage 134 may occur.

[0051] For this reason, in the present disclosure, in addition to the second filter 221, a filter 180 is further arranged in the machine tool 100. As described above, in this example, filters 180 with diameters of 2 micrometers and 5 micrometers are used. Therefore, the filter 180 can also remove fine foreign matter that has passed through the second filter 221.

[0052] Next, the operation of the filter 180 of the present disclosure will be described. The coolant from the third pump 212 is at a high pressure of, for example, about 7 megapascals. The flow rate of the coolant varies depending on the size of the tool 130. If the tool 130 is large and the inner diameter of the coolant passage 134 is large, the amount of coolant increases accordingly. The filter 180 of the present disclosure is particularly useful when the inner diameter of the coolant passage 134 is about 0.1 millimeters, and when the diameter of the microscopic space in the filter 180 is 2 micrometers or 5 micrometers, the flow rate is about 0.1 liters per minute.

[0053] This high-pressure coolant is supplied to machine tool 100. Although machine tool 100 is rotated by machining center 110 at a high speed of over 10,000 revolutions per minute, the effect of centrifugal force on the coolant is limited because the coolant passage is arranged along the rotation axis of machine tool 100. That is, filter 180 rotates around filter central axis 185, which is arranged coaxially with tool holder central axis 123 and tool central axis 132. Around filter 180, tool holder 120, tool fixture 140, tool 130, and filter holder 170 rotate at the same speed as filter 180. Therefore, the flow of coolant from coolant space 127 of tool holder 120 into filter 180 is relatively axial.

[0054] Coolant flowing relatively in the axial direction flows from the outer periphery of the filter 180 toward the inner periphery, and then flows into the coolant outlet passage 181 in the center. As described above, the effect of centrifugal force is limited, so the coolant flows toward the coolant outlet passage 181. As the coolant passes through the filter 180, even fine foreign matter that could not be filtered by the second filter 221 is removed from the coolant. The coolant that has passed through the filter 180 then enters the filter holder 170. Inside the filter holder 170, the coolant then flows into the coolant passage 134 from the coolant inlet 135 that opens at the rear end of the tool 130. The coolant is then supplied to the machining site from the coolant outlet 136 that opens at the tip of the drill 133. This is the first supply described above.

[0055] At this time, the pressure of the coolant applied to the filter 180 acts in a direction pressing the filter holder 170 toward the tool 130. Therefore, the tool 130 is simply inserted into the filter holder 170 via the O-ring 173, and the filter 180 does not come out of the tool 130. Furthermore, the rotation of the filter 180 is transmitted from the tool 130 via the filter holder 170, and this rotation transmission is also sufficient with only the O-ring 173. This is because the rotation of the tool 130 is achieved by the rotation of the tool holder 120 via the tool fixture 140. Therefore, the coolant space 127 around the filter 180 rotates at the same speed as the tool 130. Therefore, no force that causes a relative rotational difference is generated between the tool 130 and the filter 180.

[0056] As described above, in this example, the filter 180 can be held in the tool holder 120 by the simple method of simply inserting the tool 130 into the filter holder 170 using the O-ring 173. Moreover, the filter 180 does not need to have a special shape as long as it can be placed in the coolant space 127 of the tool holder 120. In other words, there is no need to individually design the shape of the filter 180 to match the tool holder 120 or the tool 130.

[0057] Furthermore, because the coolant space 127 is a space that is normally provided in the tool holder 120, a general-purpose tool holder 120 can be used as the tool holder 120. In other words, there is no need to form a special shape on the tool holder 120 for attaching and fixing the filter 180. Furthermore, the tool 130 simply needs to have its rear end protruding from the tool fixture 140, so a general-purpose tool 130 can be used. From the perspective of the tool 130 as well, there is no need to provide a special shape for attaching and fixing the filter 180.

[0058] Furthermore, the filter 180 can be replaced when the tool 130 is replaced. Furthermore, the replacement method simply involves pulling the filter 180 and filter holder 170 out of the tool 130. No special tools are required, and the filter 180 can be replaced with a simple operation. The filter 180 can be replaced when the tool 130 is replaced, but the flow rate of the coolant passing through the tool passage 235 can also be measured. That is, if the amount of coolant flowing through the tool passage 235 decreases below a predetermined amount, it is assumed that the cause is clogged filter 180. Then, when the coolant flow rate falls below the predetermined amount, the filter 180 is replaced. A clogged filter 180 can be reused by removing foreign matter through ultrasonic cleaning.

[0059] In the above example, the filter 180 and the filter holder 170 are cylindrical and have the same diameter. This is a good example because it is easy to manufacture. However, it is sufficient that the filter 180 and the filter holder 170 can be placed in the coolant space 127 of the tool holder 120. It is possible for the filter 180 and the filter holder 170 to have different diameters. Furthermore, the shape is not limited to a cylindrical shape.

[0060] In the above example, the coolant flowing through the filter 180 is from the outer periphery to the inner periphery of the filter 180. This is a desirable example, as it allows the area of ​​the filter 180 to be used effectively. However, the shape of the filter 180 is not limited to a cylindrical shape, and the flow of the coolant flowing through the filter 180 is not limited to a flow from the outer periphery to the inside. It is also possible for the coolant to flow through the filter 180 in the axial direction.

[0061] Furthermore, in the above example, an O-ring 173 is used to assemble the tool 130 and the filter holder 170. This is a desirable example because it allows for easy assembly and provides sufficient assembly force. However, it is also possible to eliminate this O-ring 173. If necessary, the tool 130 and the filter holder 170 may be press-fitted, fastened with a circlip, or fastened with screws. [Explanation of symbols]

[0062] 100 Machine tools 120 Tool Holder 127 Coolant space 130 Tools 134 Coolant passage 140 Tool Fixture 170 Filter Holder 180 filters

Claims

1. a tool holder (120) that is assembled to a machining center (110), rotates around a tool holder central axis in response to the rotation of the machining center, and has a coolant space (127) into which high-pressure coolant flows; a tool (130) attached to the tool holder via a tool attachment (140) and rotating integrally with the tool holder about the tool central axis, the tool having a coolant passage (134) therein, the coolant inlet of which opens into the coolant space of the tool holder and the coolant outlet of which opens into a machining site; a filter (180) disposed in the coolant space of the tool holder, assembled to the tool via a filter holder (170), and rotated together with the tool about a filter central axis, for removing foreign matter from the coolant flowing from the coolant space to the coolant inlet; Equipped with The tool holder central axis, the tool central axis, and the filter central axis are arranged coaxially. Machine tools (100).

2. The filter is made of sintered metal and has a cylindrical shape with a coolant outflow passage (181) in the center. the filter holder is attached to the tool so that the coolant outlet passage of the filter faces the coolant inlet of the tool; The coolant flows in from the outer periphery of the filter, passes through the coolant outflow passage in the center, and flows from the coolant inlet of the tool to the coolant passage. The machine tool according to claim 1.

3. The filter holder is screwed to the filter and is connected to the tool via an O-ring (173). The machine tool according to claim 1.

4. A tool holder that is assembled to a machining center, rotates around a central axis of the tool holder in response to the rotation of the machining center, and has a coolant space into which high-pressure coolant flows, a tool having a coolant passage therein, the coolant inlet of which opens into the coolant space of the tool holder and the coolant outlet of which opens into a machining portion, is attached to the tool holder via a tool attachment fixture, and the tool is rotated around a tool central axis integrally with the tool holder; a filter that removes foreign matter from the coolant flowing from the coolant space toward the coolant inlet is attached to the tool via a filter holder, and the filter is rotated around a filter center axis to be held in the coolant space of the tool holder; The tool holder has a central axis that is coaxial with the tool central axis and the filter central axis.

5. A filter used with a tool holder having a coolant space therein into which high-pressure coolant flows, the tool holder rotating about a tool holder central axis in response to the rotation of a machining center, and a tool having a coolant passage therein, the filter comprising: the filter is disposed in the coolant space of the tool holder and removes foreign matter from the coolant that flows from the coolant space toward the coolant passage of the tool; the filter is attached to the tool via a filter holder, and rotates around a filter central axis within the coolant space of the tool holder in response to rotation of the tool; The filter has a central axis that is coaxial with the central axis of the tool holder and the central axis of the tool.

6. A tool used together with a tool holder having a coolant space therein into which high-pressure coolant flows and which rotates about a central axis of the tool holder in response to rotation of a machining center, and a filter disposed in the coolant space of the tool holder to remove foreign matter from the coolant, The tool has a coolant passage formed therein, the coolant passage having a coolant inlet and a coolant outlet at both ends thereof; the tool is attached to the tool holder via a tool attachment and rotates around the tool central axis in response to the rotation of the tool holder; the tool is connected to the filter via a filter holder, and rotation of the tool is transmitted to the filter to rotate the filter about a filter center axis, and the coolant that has passed through the filter flows into the coolant passage from the coolant inlet; A tool in which the tool central axis is arranged coaxially with the tool holder central axis and the filter central axis.

7. a tool holder having a coolant space therein into which high-pressure coolant flows, the tool holder rotating about a tool holder central axis in response to rotation of a machining center; a tool having a coolant passage therein, the tool rotating about a tool central axis in response to rotation of the tool holder; and a filter holder that is disposed in the coolant space of the tool holder and is used together with a filter that removes foreign matter from the coolant supplied to the tool, and that assembles the tool and the filter, the filter holder is configured to assemble the filter to the tool so that a coolant outlet portion of the filter faces a coolant inlet portion of the tool, to allow the coolant to flow from the outlet portion of the filter to the inlet portion of the tool, to hold the filter in the coolant space of the tool holder, and to transmit rotation of the tool to the filter to rotate the filter about a filter central axis; a filter holder in which the tool central axis and the filter central axis are arranged coaxially with the tool holder central axis;

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