Machine tool

Abstract

To provide a machine tool capable of preventing a coolant liquid from entering the inside of a spindle housing when machining a workpiece while reducing a load on the environment.SOLUTION: A machine tool capable of machining a workpiece includes a spindle device configured to rotatably hold a spindle, to which a chuck device is attached, in a spindle housing via a bearing, a blower configured to rotate an impeller to pump seal air, and an intermediate flow path configured to supply the seal air pumped from the blower to an air flow path formed inside the spindle device and including a gap between the spindle and the spindle housing.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a machine tool that uses air to seal a flow path including a gap between a spindle and a spindle housing. [Background technology]

[0002] When machining a workpiece in a machine tool, coolant is sprayed onto the workpiece to remove chips and dissipate heat during machining. Meanwhile, in the spindle device of a machine tool that rotates and processes the workpiece, the spindle is rotatably held by a spindle housing via a bearing, but a gap always exists between the spindle and the spindle housing. Therefore, splashed coolant may infiltrate through the gap between the spindle and the spindle housing. If the infiltrated coolant adheres to the bearing in the spindle housing, it can cause bearing deterioration. Patent Document 1 describes a machine tool that uses an air purge that sends compressed air from an external device into a flow path that includes the gap between the spindle and the spindle housing to prevent coolant from infiltrating into the gap between the spindle and the spindle housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-76046 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a trend in factories to reduce the use of energy-intensive equipment such as compressors in order to reduce the burden on the environment. As a result, there is a demand for machine tools that do not use compressed air from external compressors.

[0005] In order to solve this problem, the present invention aims to provide a machine tool that can prevent coolant liquid from entering the inside of the spindle housing when machining a workpiece while reducing the burden on the environment. [Means for solving the problem]

[0006] In order to solve the above problems, the machine tool according to the present invention has a spindle device that rotatably holds a spindle, to which a chuck device is attached, in a spindle housing via a bearing, a blower that rotates an impeller to pressurize and send seal air, and an intermediate flow path that supplies the pressurized seal air from the blower to an air flow path that is formed inside the spindle device and includes a gap between the spindle and the spindle housing. [Effects of the Invention]

[0007] The machine tool having the above configuration is provided with a blower that pressurizes and sends seal air, and the seal air sent from the blower is supplied to an air flow path formed inside the spindle device via an intermediate flow path. This makes it possible to supply seal air to the air flow path and seal the gap between the spindle and the spindle housing without using an external device such as a compressor. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram illustrating the inside of a machine tool. [Figure 2] FIG. [Figure 3] FIG. 2 is a diagram illustrating the shape of a blade in an impeller. [Figure 4] FIG. 10 is a cross-sectional view of a spindle device according to a second embodiment. [Figure 5] FIG. 10 is a cross-sectional view of a spindle device according to a third embodiment. [Figure 6] FIG. 10 is a cross-sectional view of a spindle device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) An embodiment of a machine tool according to the present invention will be described below with reference to the drawings. Figure 1 is a diagram illustrating the interior of a machine tool 1. In the machine tool 1, a spindle unit 10 and a turret unit 11, which are machining devices, are covered by a machine body cover (not shown), and a machining chamber in which a workpiece is machined is configured inside.

[0010] The turret unit 11 has a tool post 12 to which a plurality of tools are attached, and a carriage 13. Tools are attached to the tool mounting surface of the tool post 12 via tool holders such as cutting holders and rotary tools. The turret unit 11 is designed to select a specific tool attached to the tool post 12 by rotating and indexing according to the machining content. The carriage 13 of the turret unit 11 is attached to a slider device that can change the position of the tool post 12 on the bed 19.

[0011] The spindle device 10 has a spindle 15 to which a chuck device 16 for gripping a workpiece is attached, and a spindle housing 14 that rotatably holds the spindle 15. The width direction of the machine body parallel to the spindle 15 is defined as the Z axis, and the vertical direction perpendicular to the Z axis is defined as the X axis. A spindle-side pulley 17 is attached to the side of the spindle 15 opposite to the end of the spindle to which the chuck device 16 is attached.

[0012] Below the spindle device 10, a spindle motor 20, which serves as a power source for rotating the spindle 15, is fixed to the bed 19. A motor-side pulley 21 is fixed to the output shaft of the spindle motor 20. A belt 18 is stretched between the motor-side pulley 21 and the spindle-side pulley 17, and the rotation of the spindle motor 20 is transmitted to the spindle-side pulley 17 by the belt 18, thereby rotating the spindle 15.

[0013] 2 is a vertical cross-sectional view of the spindle device 10 taken along a plane along the up-down direction, and for ease of explanation, the chuck device 16 is not attached to the spindle 15. Hereinafter, in the Z-axis direction in which the spindle 15 extends, the spindle end side to which the chuck device 16 of the spindle 15 is attached will be referred to as the front Z1, and the side opposite to the spindle end will also be referred to as the rear Z2.

[0014] The spindle housing 14 has a generally cylindrical main body 30 having a hollow portion through which the spindle 15 passes. Inside the main body 30, bearings 35 are attached on both the front Z1 side and the rear Z2 side, and these bearings 35 rotatably hold the spindle 15. On the front Z1 side of the main body 30, a ring-shaped ring portion 31 is provided which forms the opening edge of the hollow portion.

[0015] The main shaft 15 has a flange portion 32 on the front Z1 side, the diameter of which expands concentrically from the center line. The flange portion 32 is housed in a hollow portion formed by the ring portion 31. In addition, a cover member 33 that covers the ring portion 31 is provided on the front Z1 side of the ring portion 31.

[0016] When machining a workpiece in machine tool 1, coolant is sprayed onto the workpiece for the purposes of removing chips and dissipating heat during machining. In spindle unit 10, a gap exists between spindle 15 and spindle housing 14, and scattered coolant may enter spindle housing 14 through the gap. Therefore, spindle unit 10 has an air purge structure that prevents coolant from entering spindle housing 14 by supplying seal air to air flow path 40, which includes the gap between spindle 15 and spindle housing 14. In this embodiment, spindle unit 10 has an inlet passage 41 formed inside ring portion 31, which is part of air flow path 40. This inlet passage 41, a gap 42 between ring portion 31 and flange portion 32, and a gap 43 between ring portion 31 and cover member 33 form a labyrinth-shaped air flow path 40 through which seal air flows.

[0017] In the machine tool 1 configured as described above, compressed air has conventionally been supplied to the air flow path 40 of the spindle unit 10 from an external device such as a compressor installed in a factory. However, to reduce the burden on the environment, it is becoming desirable not to use compressor devices, which consume a lot of energy, in factories. Therefore, the machine tool 1 according to this embodiment is provided with a blower unit 50, and by supplying pressurized seal air from this blower unit 50 to the air flow path 40, a configuration is achieved in which a compressor unit is not used.

[0018] Returning to Fig. 2, blower 50 is provided on the rear Z2 side of spindle housing 14, and has impeller 51 and case 52 that rotatably holds impeller 51. Impeller 51 is fixed to spindle-side pulley 17 so that its center of rotation coincides with the center line of spindle 15. As a result, impeller 51 is configured to be rotatable together with spindle-side pulley 17 based on the rotation of spindle 15.

[0019] 3(a) and 3(b) are views of the impeller 51 as viewed from the side indicated by the arrow A in FIG. 2. A forward-rotation-side blade 53 is provided on the front Z1 side of the impeller 51, and a reverse-rotation-side blade 54 is provided on the rear Z2 side. When viewed from the direction of the arrow A in FIG. 2, the inclination directions of the blades 53 and 54 differ by approximately 180 degrees. When the main shaft 15 rotates forward, the impeller 51 pumps out seal air at exhaust pressure (i.e., positive pressure) on the side of the forward-rotation-side blade 53. On the other hand, when the main shaft 15 rotates reversely, the impeller 51 pumps out seal air at exhaust pressure on the side of the reverse-rotation-side blade 54.

[0020] The case 52 has a pumping chamber therein, which is a hollow space capable of accommodating the impeller 51. The impeller 51 divides the pumping chamber into a pumping space 52A on the front Z1 side where the forward-rotation-side blades 53 of the impeller 51 are disposed, and a pumping space 52B on the rear Z2 side where the reverse-rotation-side blades 54 are disposed. The pumping space 52A of the case 52 is connected to a forward-rotation-side intermediate flow path 55 for supplying the seal air pumped by the forward-rotation-side blades 53 to the air flow path 40. The pumping space 52B side of the case 52 is connected to a reverse-rotation-side intermediate flow path 56 for supplying the seal air pumped by the reverse-rotation-side blades 54 to the air flow path 40. In this embodiment, the intermediate flow paths 55, 56 are, for example, flexible pipes and are connected to the case 52 outside the spindle housing 14.

[0021] The intermediate flow paths 55, 56 are connected to a junction chamber 57 provided on the front Z1 side of the spindle housing 14 via pressure valves 58A, 58B. The junction chamber 57 is a space formed in the main body 30 and connected to the inlet passage 41 of the ring portion 31. The pressure valve 58A is interposed between the forward rotation side intermediate flow path 55 and the junction chamber 57. When seal air at exhaust pressure flows into the forward rotation side intermediate flow path 55, the valve opens, allowing the seal air to flow into the junction chamber 57. The pressure valve 58B is interposed between the reverse rotation side intermediate flow path 56 and the junction chamber 57. When seal air at exhaust pressure flows into the reverse rotation side intermediate flow path 56, the valve opens, allowing the seal air to flow into the junction chamber 57.

[0022] In the spindle unit 10 configured as described above, as the impeller 51 rotates in the forward direction in response to the rotation of the spindle 15, the forward-rotation blades 53 create exhaust pressure in the pumping space 52A of the case 52, and the seal air flowing into the forward-rotation-side intermediate flow path 55 opens the pressure valve 58A, causing the seal air to flow into the junction chamber 57. Note that as the impeller 51 rotates in the forward direction, the pumping space 52B is under intake pressure, so the pressure valve 58B connected to the reverse-rotation-side intermediate flow path 56 does not open. The seal air that has flowed into the junction chamber 57 flows into the inlet path 41 of the air flow path 40, whereby the seal air seals the gap between the spindle 15 and the spindle housing 14. The seal air is then discharged to the outside of the spindle housing 14 through the gap 43 in the air flow path 40 between the ring portion 31 and the cover member 33.

[0023] Meanwhile, as impeller 51 rotates in the reverse direction in accordance with the rotation of spindle 15, reverse-side blades 54 create exhaust pressure in pumping space 52B of case 52, and seal air flowing through reverse-side intermediate flow path 56 opens pressure valve 58B, causing the seal air to flow into junction chamber 57. Note that, as pumping space 52A becomes under intake pressure due to the rotation of impeller 51, pressure valve 58A connected to forward-side intermediate flow path 55 does not open. The seal air that has flowed into junction chamber 57 then flows into air flow path 40. The seal air supplied to air flow path 40 flows through air flow path 40, sealing the gap between spindle 15 and spindle housing 14, and is then discharged from air flow path 40 to the outside of spindle housing 14.

[0024] The present embodiment described above can achieve the following effects. Machine tool 1 has blower 50 that rotates impeller 51 to pressurize and send seal air, and intermediate flow paths 55, 56 that supply the seal air sent under pressure from blower 50 to air flow path 40 in spindle unit 10. This allows machine tool 1 to seal the gap between spindle 15 and spindle housing 14 with seal air without receiving a supply of compressed air from an external device such as a compressor. As a result, the sealing effect of spindle unit 10 can be maintained while reducing the environmental load.

[0025] In blower device 50, impeller 51 is fixed to main shaft 15 via main shaft-side pulley 17, and impeller 51 is rotated based on the rotation of main shaft 15. This allows the power required to rotate impeller 51 to be shared with the power required to rotate main shaft 15, eliminating the need for additional power and further reducing the burden on the environment.

[0026] The intermediate flow paths include a forward rotation side intermediate flow path 55 that supplies seal air to the air flow path 40 when the impeller 51 rotates in the forward direction, and a reverse rotation side intermediate flow path 56 that supplies seal air to the air flow path 40 when the impeller 51 rotates in the reverse direction. This makes it possible to continue supplying seal air to the air flow path 40 even when the rotation direction of the impeller 51 changes with the rotation of the main shaft 15 and the direction in which the seal air is compressed changes.

[0027] (Second embodiment) In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will not be repeated. Fig. 4 is a vertical cross-sectional view of a spindle device 10 according to a modified example. The blower device 60 is provided in the main body portion 30 of the spindle housing 14, and has an impeller 61 and an operating chamber 62 that houses the impeller 61. The impeller 61 is fixed to the spindle 15, and its center of rotation coincides with the center line (center of rotation) of the spindle 15. In the present embodiment as well, the impeller 61 has a forward-rotation-side blade 63 on the front Z1 side and a reverse-rotation-side blade 64 on the rear Z2 side.

[0028] The working chamber 62 is a hollow space capable of accommodating the impeller 61, and is partitioned by the impeller 61 into a pumping space 62A on the front Z1 side where the forward-rotation blades 63 of the impeller 61 are disposed, and a pumping space 62B on the rear Z2 side where the reverse-rotation blades 64 are disposed. In this embodiment, the pumping space 62A in the working chamber 62 has a discharge port provided on the front Z1 side of the impeller 61, and this discharge port is connected to the forward-rotation intermediate flow path 55 via a pressure valve 65. The pumping space 62B in the working chamber 62 has a discharge port provided on the rear Z2 side of the impeller 61, and this discharge port is connected to the reverse-rotation intermediate flow path 56 via a pressure valve 66.

[0029] The forward rotation side intermediate flow passage 55 and the reverse rotation side intermediate flow passage 56 are directly connected to the inlet passage 41 of the ring portion 31. Therefore, the forward rotation side intermediate flow passage 55 and the reverse rotation side intermediate flow passage 56 are connected via the air flow passage 40.

[0030] In the above configuration, impeller 61 rotates in the normal direction in accordance with the rotation of spindle 15, causing exhaust pressure in pumping space 62A of working chamber 62. This opens pressure valve 65 provided at the discharge port of pumping space 62A, and seal air flows into air flow path 40 via normal-rotation-side intermediate flow path 55. The seal air flows through air flow path 40, sealing the gap between spindle 15 and spindle housing 14, and is then discharged from air flow path 40 to the outside of spindle housing 14.

[0031] Meanwhile, impeller 61 rotates in the reverse direction in accordance with the rotation of spindle 15, causing exhaust pressure in pumping space 62B of working chamber 62. This opens pressure valve 66, and seal air flows into air flow path 40 via reverse-rotation-side intermediate flow path 56. The seal air supplied to air flow path 40 seals the gap between spindle 15 and spindle housing 14 by flowing through air flow path 40, and is then discharged from air flow path 40 to the outside of spindle housing 14.

[0032] In the present embodiment described above, the blower device 60 has the impeller 61 fixed to the main shaft, and pressurizes and sends seal air by rotating the impeller 61 based on the rotation of the main shaft 15. This allows the power required to rotate the impeller 61 to be shared with the power required to rotate the main shaft 15, so there is no need to add new power, and the burden on the environment can be further reduced.

[0033] Since each intermediate flow path 55, 56 is formed inside the spindle housing 14, the increase in the size of the spindle device 10 can be suppressed compared to when each intermediate flow path 55, 56 is provided outside the spindle housing 14.

[0034] (Third embodiment) In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated. In this embodiment, the blower device 70 is connected to the output shaft of the spindle motor 20 via the motor-side pulley 21, which is a transmission member, and rotates the impeller based on the force transmitted by the motor-side pulley 21.

[0035] 5, the spindle device 10 has a blower 70, similar to the first embodiment, and this blower 70 has an impeller 71 and a case 72 that rotatably holds the impeller 71. Similar to the first embodiment, the impeller 71 has a forward-rotating blade on the front Z1 side and a reverse-rotating blade on the rear Z2 side.

[0036] A rotating shaft 71A of an impeller 71 in the blower 70 is connected to the motor-side pulley 21 attached to the output shaft of the spindle motor 20, and the impeller 71 can be rotated by the rotation of the motor-side pulley 21. In this embodiment, the motor-side pulley 21 is used as a transmission member, but alternatively, a transmission pulley may be attached to the output shaft of the spindle motor 20 in addition to the motor-side pulley 21, and the rotation of the spindle motor 20 may be transmitted to the impeller 71 by this transmission pulley. Alternatively, the rotation of the output shaft of the spindle motor 20 may be transmitted to the rotating shaft 71A of the impeller 71 by a transmission gear, as long as the rotation of the output shaft of the spindle motor 20 is transmitted to the main shaft 15 via a transmission gear.

[0037] In spindle unit 10 having the above configuration, as in the first embodiment, either pressure valve 58A or 58B is opened by seal air that is pressurized and fed in accordance with the rotation direction of impeller 71, and the seal air flows into junction chamber 57. Then, the seal air flows from junction chamber 57 into air flow path 40, thereby sealing the gap between spindle 15 and spindle housing 14.

[0038] In the embodiment described above, in blower device 70, impeller 71 is connected to the output shaft of spindle motor 20, which is the power source that rotates main shaft 15, via motor-side pulley 21, which is a transmission member, and impeller 71 is rotated based on the transmitted rotation of spindle motor 20. This allows the power required to rotate impeller 71 to be shared with the power required to rotate main shaft 15, so there is no need to add new power, and the burden on the environment can be further reduced.

[0039] (Fourth embodiment) In the fourth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated. In this embodiment, as shown in Fig. 6, the air blower 80 is an electric fan, and an impeller 81 can be rotated by the power of a motor (not shown).

[0040] The case 82 of the blower 80 has an operating chamber in which the impeller 81 is rotatably held, and an air collection chamber that collects the seal air compressed and sent by the impeller 81. The air collection chamber has a discharge port that is connected to the inlet passage 41 of the ring portion 31 via an intermediate flow path 83.

[0041] In the spindle unit 10 having the above configuration, the seal air compressed and fed by the rotation of the impeller 81 is collected in the air collection chamber and flows from this air collection chamber into the air flow path 40 via the intermediate flow path 83. In this embodiment, the impeller 81 is electrically driven by a motor (not shown), so the direction in which the seal air is compressed and fed can be kept constant regardless of the rotation direction of the spindle 15.

[0042] In the present embodiment described above, the blower 80 electrically drives the impeller 81, so it is possible to freely design the location of the blower 80. This makes it possible to shorten the intermediate flow path 83 connecting the blower 80 and the air flow path 40, reducing the loss of seal air within the flow path and ensuring that the air flow path 40 is sealed with seal air.

[0043] Although one embodiment of the present invention has been described above, the present invention is not limited to this and various modifications are possible without departing from the spirit of the present invention. In machine tool 1, by using a rotary tool on the turret device 11 side, a workpiece may be machined while the rotation of the spindle 15 on the spindle device 10 is stopped. Therefore, a thin-film pressure valve may be provided in each gap in air flow path 40. As a result, when the spindle 15 is not rotating during workpiece machining, no seal air pressure is applied to the air flow path 40, and the thin-film pressure valve provided in the air flow path 40 closes, preventing coolant from entering the inside of the spindle housing 14 through the air flow path 40. On the other hand, when the spindle 15 is rotating during workpiece machining, seal air is supplied to the air flow path 40 from the blower, opening the thin-film pressure valve in the air flow path 40 and supplying seal air to the air flow path.

[0044] In the first to third embodiments described above, when the machine tool 1 is configured to rotate the spindle 15 in only one direction, the spindle device 10 only needs to have the normal rotation side intermediate flow passage as the intermediate flow passage. [Explanation of symbols]

[0045] 1...machine tool, 10...spindle device, 14...spindle housing, 15...spindle, 17...spindle side pulley, 35...bearing, 40...air flow path, 50, 60, 70, 80...blower device, 51, 61, 71, 81...impeller, 55, 56, 83...intermediate flow path

Claims

1. a spindle device that rotatably holds a spindle to which a chuck device is attached in a spindle housing via a bearing; a blower that rotates an impeller to pressurize and send seal air; an intermediate flow path that supplies the seal air pressurized and fed from the blower device to an air flow path that is formed inside the spindle device and includes a gap between the spindle and the spindle housing.

2. The air blower device is The machine tool according to claim 1 , wherein the impeller is fixed to the main shaft, and the impeller is rotated based on the rotation of the main shaft.

3. The air blower device is 2. The machine tool according to claim 1, wherein the impeller is connected via a transmission member to an output shaft of a motor that is a power source that rotates the main shaft, and the impeller is rotated based on rotation of the motor transmitted by the transmission member.

4. The intermediate flow path is a forward rotation side intermediate flow passage that supplies the seal air to the air flow passage when the impeller rotates forward; 4. The machine tool according to claim 2, further comprising a reverse rotation side intermediate flow passage that supplies the seal air to the air flow passage when the impeller rotates in a reverse direction.

5. The machine tool according to claim 1 , wherein the intermediate flow passage is formed in the spindle housing.

6. 2. The machine tool according to claim 1, further comprising a pressure valve that is provided in the air flow path, the valve opening due to the pressure of the seal air to open the air flow path, and the valve closing when the pressure of the seal air is not applied to the air flow path to close the air flow path.

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