JP2018108609A - Machine Tools - Google Patents

Abstract

A machine tool that suppresses vibrations of a spindle and prevents a decrease in machining accuracy of a workpiece is provided.
In a machine tool comprising a main shaft for mounting a tool, a motor for driving the main shaft, and a coupling for connecting the rotation shaft of the motor and the main shaft, the coupling is an elastic member for coupling to the rotation shaft. A machine tool comprising: a connecting portion that connects the elastic portion and the main shaft; and a storage box that stores the elastic portion and the connecting portion, and a viscous fluid is injected into the storage box.
[Selection] Figure 3

Description

  The present invention relates to a machine tool that processes a workpiece with a tool mounted on a spindle.

  The machine tool includes a main shaft on which a tool is mounted and a motor that drives the main shaft. The rotating shaft of the motor and the main shaft are connected via a coupling. Since the coupling includes a leaf spring, the connection can be maintained even if eccentricity occurs between the main shaft and the rotation shaft of the motor (see, for example, Patent Document 1).

Japanese Patent No. 4582001

  When a workpiece is machined with a tool, the vibration of the tool is transmitted to the coupling via the main shaft. The leaf spring of the coupling is elastically deformed, and the main shaft vibrates greatly in the vicinity of the coupling. The machining accuracy of the workpiece is reduced by the vibration of the spindle.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a machine tool that suppresses vibration of a main shaft and prevents a reduction in machining accuracy of a workpiece.

  A machine tool according to the present invention is a machine tool including a main shaft on which a tool is mounted, a motor that drives the main shaft, and a rotation shaft of the motor and a coupling that connects the main shaft, and the coupling includes the rotation shaft. An elastic portion connected to the elastic portion, a connecting portion connecting the elastic portion and the main shaft, and a storage box for storing the elastic portion and the connection portion, and a viscous fluid is injected into the storage box. To do.

  In the present invention, since the viscous fluid is injected into the storage box, the viscous fluid prevents the vibration of the main shaft, and the vibration of the main shaft is attenuated.

  The machine tool according to the present invention is characterized in that a resistance portion against a viscous fluid is provided in the connecting portion.

  In the present invention, the resistance portion comes into contact with the viscous fluid and the contact area with the viscous fluid is increased, so that the resistance of the main shaft to the viscous fluid is further increased.

  The machine tool according to the present invention is characterized in that the resistance portion has a plate shape perpendicular to the main axis, and a protrusion is provided on one surface of the resistance portion.

  In the present invention, the provision of the protrusions increases the contact area with the viscous fluid, so that the resistance of the main shaft to the viscous fluid is further increased.

  The machine tool according to the present invention includes a plurality of the resistance portions, the plurality of resistance portions are arranged in parallel in the axial direction of the main shaft, and protrudes in the radial direction of the main shaft from the inner surface of the housing box, A protruding plate disposed between the resistance portions is provided.

  In the present invention, by providing the protruding plate between the plurality of resistance portions, the resistance portion vibrates when the main shaft vibrates, and the pressure of the viscous fluid between the resistance portion and the protruding plate increases. That is, the vibration energy of the main shaft is converted into thermal energy of a viscous fluid by friction inside the fluid, and the vibration of the main shaft is attenuated.

  The machine tool according to the present invention is characterized in that a heat radiating portion is provided on the outer surface of the housing box.

  In the present invention, when the main shaft vibrates, the temperature of the viscous fluid that has absorbed the vibration energy of the main shaft rises. The heat radiating part releases the heat of the viscous fluid to the outside and prevents the spindle and the coupling from being overheated.

  In the machine tool according to the present invention, since the viscous fluid is injected into the storage box, the viscous fluid prevents the vibration of the main shaft, and the vibration of the main shaft is attenuated. As a result, it is possible to prevent a decrease in workpiece machining accuracy.

1 is a perspective view schematically showing a machine tool. It is a longitudinal cross-sectional view which shows a spindle and a spindle motor schematically. It is an enlarged vertical sectional view of the vicinity of the coupling. It is a disassembled perspective view which briefly shows a storage box. It is a disassembled perspective view which briefly shows an elastic part and a connection part. It is a partial expansion longitudinal cross-sectional view which shows the structure of a connection part vicinity schematically.

  Hereinafter, the present invention will be described based on the drawings showing a machine tool according to an embodiment. In the following description, up and down, left and right, and front and rear indicated by arrows in the figure are used. FIG. 1 is a perspective view schematically showing a machine tool.

  The machine tool includes a rectangular base 1 extending forward and backward. A work holding unit 3 that holds a work is provided on the front side of the upper portion of the base 1. The work holding unit 3 can rotate around the A axis with the left-right direction as the axial direction and the C axis with the up-down direction as the axial direction.

  A support base 2 for supporting a column 4 described later is provided on the rear side of the upper part of the base 1. A Y-axis direction moving mechanism 10 that moves in the front-rear direction is provided on the upper portion of the support base 2. The Y-axis direction moving mechanism 10 includes two rails 11 extending in the front-rear direction, a Y-axis screw shaft 12, a Y-axis motor 13, and a bearing 14.

  The rails 11 are provided on the left and right of the upper part of the support base 2, respectively. The Y-axis screw shaft 12 extends in the front-rear direction and is provided between the two rails 11. A bearing 14 is provided at each of the front end portion and the middle portion (not shown) of the Y-axis screw shaft 12. The Y-axis motor 13 is connected to the rear end portion of the Y-axis screw shaft 12.

  A nut (not shown) is screwed onto the Y-axis screw shaft 12 via a rolling element (not shown). The rolling element is, for example, a ball. A plurality of sliders 15 are slidably provided on each rail 11. A moving plate 16 is connected to the upper part of the nut and the slider 15. The moving plate 16 extends in the horizontal direction. As the Y-axis motor 13 rotates, the Y-axis screw shaft 12 rotates, the nut moves in the front-rear direction, and the moving plate 16 moves in the front-rear direction.

  An X-axis direction moving mechanism 20 that moves in the left-right direction is provided on the upper surface of the moving plate 16. The X-axis direction moving mechanism 20 includes two rails 21 extending left and right, an X-axis screw shaft 22, an X-axis motor (not shown), and a bearing 24.

  The rails 21 are provided at the front and rear sides of the upper surface of the movable plate 16. The X-axis screw shaft 22 extends left and right and is provided between the two rails 21. A bearing 24 is provided at each of the left end portion and midway portion (not shown) of the X-axis screw shaft 22. The X-axis motor is connected to the right end portion of the X-axis screw shaft 22.

  A nut (not shown) is screwed onto the X-axis screw shaft 22 via a rolling element (not shown). A plurality of sliders 26 are slidably provided on each rail 21. The column 4 is connected to the upper part of the nut and the slider 26. Column 4 is columnar. As the X-axis motor rotates, the X-axis screw shaft 22 rotates, the nut moves in the left-right direction, and the column 4 moves in the left-right direction.

  A Z-axis direction moving mechanism 30 that moves in the vertical direction is provided on the front surface of the column 4. The Z-axis direction moving mechanism 30 includes two rails 31 extending vertically, a Z-axis screw shaft 32, a Z-axis motor 33, and a bearing 34.

  The rails 31 are provided on the left and right sides of the front surface of the column 4, respectively. The Z-axis screw shaft 32 extends vertically and is provided between the two rails 31. A bearing 34 is provided at each of a lower end portion and a midway portion of the Z-axis screw shaft 32. In addition, illustration of the bearing provided in the middle part is abbreviate | omitted. The Z-axis motor 33 is connected to the upper end portion of the Z-axis screw shaft 32.

  A nut (not shown) is screwed onto the Z-axis screw shaft 32 via a rolling element (not shown). A plurality of sliders 35 are slidably provided on each rail 31. The spindle head 5 is connected to the front part of the nut and the slider 35. The Z-axis screw shaft 32 is rotated by the rotation of the Z-axis motor 33, the nut moves in the vertical direction, and the spindle head 5 moves in the vertical direction. The Z-axis motor 33, the Z-axis screw shaft 32, the nut and the rolling element constitute a ball screw mechanism.

  A main shaft 5 a extending vertically is provided in the main shaft head 5. The main shaft 5a rotates around the axis. A spindle motor 6 is provided at the upper end of the spindle head 5. A tool is attached to the lower end of the main shaft 5a. The spindle 5a is rotated by the rotation of the spindle motor 6, and the tool is rotated. The rotated tool processes the workpiece held in the workpiece holding unit 3.

  The machine tool includes a tool changer (not shown) for changing tools. The tool changer exchanges a tool housed in a tool magazine (not shown) and a tool mounted on the spindle 5a.

  FIG. 2 is a longitudinal sectional view schematically showing the main shaft 5 a and the main shaft motor 6. The main shaft motor 6 has a rotating shaft 6a protruding downward. The upper end portion of the main shaft 5 a and the rotating shaft 6 a are connected via a coupling 7. A bearing 5b and a spacer 5c are provided around the lower portion of the main shaft 5a. The bearing 5b and the spacer 5c are disposed between the spindle head 5 and the spindle 5a.

  FIG. 3 is an enlarged longitudinal sectional view in the vicinity of the coupling 7. The coupling 7 includes an elastic part 76 connected to the rotating shaft 6 a, a connecting part 80 connecting the elastic part 76 and the main shaft 5 a, and a storage box 70 for storing the connecting part 80 and the elastic part 76.

  FIG. 4 is an exploded perspective view schematically showing the storage box 70. The storage box 70 includes a top surface portion 74, a first body portion 71, a second body portion 72, a third body portion 73, and a bottom portion 75. The top surface portion 74 has a bottomed cylindrical shape with the bottom disposed on the upper side. A flange 74 b is provided at the lower edge portion of the top surface portion 74. A cylindrical first body portion 71 is coaxially disposed below the top surface portion 74. A flange 71 b is provided on the upper edge of the first body 71. The two flanges 71b and 74b face each other. An annular groove 71a is formed on the upper end surface of the first body 71, and a sealing ring 71d is provided in the groove 71a. 71 d of sealing rings are packing, for example, and seal the clearance gap between the top | upper surface part 74 and the 1st trunk | drum 71 watertightly.

  A cylindrical second body 72 is coaxially disposed below the first body 71. An annular spacer 72 b protruding upward is provided on the upper surface of the second body portion 72. An annular groove 72a is provided on the upper surface of the spacer 72b, and a sealing ring 72d is provided in the groove 72a. The sealing ring 72d is packing, for example, and seals the gap between the first body 71 and the second body 72 in a watertight manner. An annular radiating fin 71 c is provided at the lower edge of the first body 71.

  A cylindrical third barrel portion 73 is coaxially disposed below the second barrel portion 72. An annular spacer 73 b protruding upward is provided on the upper surface of the third body portion 73. An annular groove 73a is provided on the upper surface of the spacer 73b, and a sealing ring 73d is provided in the groove 73a. The sealing ring 73d is, for example, a packing, and seals the gap between the second barrel portion 72 and the third barrel portion 73 in a watertight manner. An annular radiating fin 72 c is provided on the lower edge of the second body 72. An annular radiating fin 73 c is provided at the lower edge of the third body portion 73.

  A bottomed cylindrical bottom portion 75 is coaxially disposed below the third body portion 73. An annular spacer 75b protruding upward is provided on the upper surface of the bottom 75. An annular groove 75a is provided on the upper surface of the spacer 75b, and a sealing ring 75d is provided in the groove 75a. The sealing ring 75d is a packing, for example, and seals the gap between the third body portion 73 and the bottom portion 75 in a watertight manner. An annular radiating fin 75 c is provided on the outer peripheral surface of the bottom portion 75. Each radiation fin 71c, 72c, 73c, 75c comprises a thermal radiation part.

  The spacer 72 b forms a gap between the first body 71 and the second body 72. A first disk 91 is provided in this gap. A through hole 91 b is provided in the radial center of the first disk 91. The diameter of the through hole 91b is larger than a second connecting plate 82 (see FIG. 5) described later. As shown in FIG. 4, a plurality of protrusions 91 a extending in the radial direction are formed on the upper surface of the first disk 91. The plurality of protrusions 91a are arranged radially.

  The spacer 73 b forms a gap between the second barrel portion 72 and the third barrel portion 73. A second disk 92 is provided in this gap. A through hole 92 b is provided at the radial center of the second disk 92. The diameter of the through hole 92b is larger than a third connecting plate 83 (see FIG. 5) described later. As shown in FIG. 4, a plurality of protrusions 92 a extending in the radial direction are formed on the upper surface of the second disk 92. The plurality of protrusions 92a are arranged radially.

  The spacer 75 b forms a gap between the third body portion 73 and the bottom portion 75. A third disk 93 is provided in this gap. A through hole 93 b is provided in the radial center of the third disk 93. The diameter of the through hole 93b is larger than that of a fourth connecting plate 84 (see FIG. 5) described later. As shown in FIG. 4, a plurality of protrusions 93 a extending in the radial direction are formed on the upper surface of the third disk 93. The plurality of protrusions 93a are arranged radially.

  A fitting cylinder 74 a is provided on the outer upper surface of the top surface portion 74. The rotating shaft 6a is fitted in the fitting cylinder 74a. An elastic portion 76 is fixed to the upper inner surface of the top surface portion 74 with screws 50. The rotating shaft 6 a is connected to the elastic portion 76 via the fitting cylinder 74 a and the top surface portion 74.

  The elastic portion 76 includes a first hub 76a disposed on the upper side, a second hub 76b disposed on the lower side, and a leaf spring 76c disposed between the first hub 76a and the second hub 76b. The first hub 76a and the second hub 76b have a disk shape and are arranged coaxially. The first hub 76a is connected to the top surface portion 74 by a screw 50, and is connected to a leaf spring 76c by a bolt (not shown). The second hub 76b is connected to the leaf spring 76c with a bolt (not shown). The lower surface of the second hub 76 b is connected to the upper portion of the elastic portion 76.

  A through-hole 75d penetrating vertically is provided at the center in the radial direction of the bottom 75. An insertion shaft 78 is inserted into the through hole 75d. The upper part of the insertion shaft 78 is connected to the lower part of the elastic part 76. A recess 78b for inserting the main shaft 5a is formed in the lower portion of the insertion shaft 78. A collet 79a is provided at the lower end of the recess 78b.

  A screw groove 78 a is formed on the lower outer peripheral surface of the insertion shaft 78. The main shaft 5a is inserted into the collet 79a and the recess 78b. The collet 79a holds the main shaft 5a. A tightening nut 79b is provided below the insertion shaft 78 and outside the collet 79a. The tightening nut 79 b engages with the screw groove 78 a and fixes the main shaft 5 a to the insertion shaft 78.

  FIG. 5 is an exploded perspective view schematically showing the elastic portion 76 and the connecting portion 80, and FIG. 6 is a partially enlarged longitudinal sectional view schematically showing the configuration in the vicinity of the connecting portion 80. The connecting portion 80 includes a first connecting board 81, a second connecting board 82, a third connecting board 83, and a fourth connecting board 84. The first connection board 81 to the fourth connection board 84 have a circular shape and are arranged vertically coaxially. The second connection board 82 is located below the first connection board 81, the third connection board 83 is located below the second connection board 82, and the fourth connection board 84 is located below the third connection board 83. Is located. The second connecting board 82 is located inside the through hole 91 b of the first disk 91, the third connecting board 83 is located inside the through hole 92 b of the second disk 92, and the third connecting board 83 is located on the third disk 93. It is located inside the through hole 93b.

  A male screw 81a projecting downward is provided at the radial center of the lower surface of the first connecting board 81. A circular spacer 82a that protrudes upward is provided at a central portion in the upper surface radial direction of the second connecting plate 82. A female screw 82b is provided at the center of the spacer 82a. A male screw 82c projecting downward is provided at the radial center of the lower surface of the second connecting plate 82.

  A circular spacer 83 a that protrudes upward is provided at the central portion in the upper surface radial direction of the third connecting plate 83. A female screw 83b is provided at the center of the spacer 83a. A male screw 83c projecting downward is provided at the radial center of the lower surface of the third connecting plate 83.

  A circular spacer 84 a that protrudes upward is provided at the central portion in the upper surface radial direction of the fourth connecting panel 84. A female screw 84b is provided at the center of the spacer 84a. A male screw 84c projecting downward is provided at the radial center of the lower surface of the fourth connecting board 84.

  The upper surface of the first connection board 81 is connected to the second hub 76b. The male screw 81 a of the first connecting plate 81 engages with the female screw 82 b of the second connecting plate 82. The male screw 82 c of the second connecting plate 82 engages with the female screw 83 b of the third connecting plate 83. The male screw 83 c of the third connection board 83 engages with the female screw 84 b of the fourth connection board 84.

  A cylindrical protrusion 78e is provided at the center of the upper end surface of the insertion shaft 78. A circular spacer 78g that protrudes upward is provided at the central portion in the radial direction of the protrusion 78e. A female screw 78f is provided at the center of the spacer 78g. The protrusion 78e is inserted into the storage box 70 through the through hole 75d.

  The male screw 84c of the fourth connecting plate 84 engages with the female screw 78f of the spacer 78g. On the upper end surface of the insertion shaft 78, an annular groove 78c is formed around the protrusion 78e. A sealing ring 78d is provided in the groove 78c. The sealing ring 78d is a packing, for example. The sealing ring 78d seals the gap between the insertion shaft 78 and the bottom 75 in a watertight manner.

  The spacer 82 a forms a gap between the first connecting board 81 and the second connecting board 82. A fourth disk 94 perpendicular to the main shaft 5a is provided in this gap. A through hole 94 b is provided at the radial center of the fourth disk 94. The spacer 82a is inserted into the through hole 94b. As shown in FIG. 5, a plurality of protrusions 94 a extending in the radial direction are formed on the upper surface of the fourth disk 94. The plurality of protrusions 94a are arranged radially. The fourth disk 94 is located between the first disk 91 and the first connecting board 81.

  The spacer 83 a forms a gap between the second connecting plate 82 and the third connecting plate 83. A fifth disk 95 perpendicular to the main shaft 5a is provided in this gap. A through hole 95 b is provided at the radial center of the fifth disk 95. The spacer 83a is inserted into the through hole 95b. As shown in FIG. 5, a plurality of protrusions 95 a extending in the radial direction are formed on the upper surface of the fifth disk 95. The plurality of protrusions 95a are arranged radially. The fifth disk 95 is located between the first disk 91 and the second disk 92.

  The spacer 84 a forms a gap between the third connection board 83 and the fourth connection board 84. A sixth disk 96 perpendicular to the main shaft 5a is provided in this gap. A through hole 96 b is provided in the radial center of the sixth disk 96. The spacer 84a is inserted into the through hole 96b. As shown in FIG. 5, a plurality of protrusions 96 a extending in the radial direction are formed on the upper surface of the sixth disk 96. The plurality of protrusions 96a are arranged radially. The sixth disk 96 is located between the second disk 92 and the third disk 93.

  The spacer 78g forms a gap between the fourth connecting plate 84 and the protruding portion 78e. A seventh disk 97 perpendicular to the main shaft 5a is provided in this gap. A through hole 97 b is provided in the radial center of the seventh disk 97. The spacer 78g is inserted into the through hole 97b. As shown in FIG. 5, a plurality of protrusions 97 a extending in the radial direction are formed on the upper surface of the seventh disk 97. The plurality of protrusions 97a are arranged radially. The seventh disk 97 is located between the third disk 93 and the bottom 75.

  The fourth disk 94 to the seventh disk 97 are arranged in the axial direction of the main shaft 5a. The first disk 91 is located between the fourth disk 94 and the fifth disk 95. The second disk 92 is located between the fifth disk 95 and the sixth disk 96. The seventh disk 97 is located between the sixth disk 96 and the seventh disk 97. The first disk 91 to the third disk 93 constitute a protruding plate. The fourth disk 94 to the seventh disk 97 constitute a resistance part. The shape of the protruding plate is not limited to the disk shape. For example, one or a plurality of rectangular plates protruding inward from the storage box 70 may be used as the protruding plate. The shape of the resistance portion is not limited to the disk shape. For example, one or a plurality of rectangular plates protruding radially outward from the connecting portion 80 may be used as the resistance portion.

  The container box 70 is filled with a liquid viscous fluid 60, for example, silicon oil, and the viscous fluid 60 fills the container box 70. The viscosity of the viscous fluid 60 is relatively high, and the range of the viscosity coefficient of the viscous fluid 60 is, for example, 20 to 50 [Pa · s]. Each sealing ring 71d, 72d, 73d, 75d, 78d is provided between the top surface 74 and the first body 71, between the first body 71 and the second body 72, and between the second body 72 and the third body. The gaps between the portions 73, between the third body portion 73 and the bottom portion 75, and between the insertion shaft 78 and the bottom portion 75 are sealed in a watertight manner to prevent the viscous fluid 60 from leaking out.

  The tool vibrates during workpiece machining. The main shaft 5a vibrates greatly in the vicinity of the coupling 7. Since the machine tool injects the highly viscous viscous fluid 60 into the storage box 70, the viscous fluid 60 prevents the vibration of the main shaft 5a, and the vibration of the main shaft 5a is attenuated. As a result, it is possible to prevent a decrease in workpiece machining accuracy.

  Further, since the fourth disk 94 to the seventh disk 97 are in contact with the viscous fluid 60 and the contact area with the viscous fluid 60 is increased, when the main shaft 5a vibrates, the resistance of the main shaft 5a with respect to the viscous fluid 60 is increased and the shortness is shortened. Vibration attenuates over time.

  Further, by providing the protrusions 91a, 92a, 93a, the contact area with the viscous fluid 60 is increased, so that the resistance of the main shaft 5a to the viscous fluid 60 is further increased, and the vibration is attenuated in a shorter time.

  Further, by providing the first disk 91 to the third disk 93 between the fourth disk 94 to the seventh disk 97, the fourth disk 94 to the seventh disk 97 vibrate when the main shaft 5a vibrates. The pressure of the viscous fluid 60 between the seventh disk 97 and the first disk 91 to the third disk 93 is increased. That is, since the vibration energy of the main shaft 5a is converted into the pressure energy of the viscous fluid 60, the vibration of the main shaft 5a is easily attenuated.

  When the main shaft 5a vibrates, the temperature of the viscous fluid 60 that has absorbed the vibration energy of the main shaft 5a rises. The radiation fins 71c, 72c, and 75c release the heat of the viscous fluid 60 to the outside, and prevent the spindle 5a and the coupling 7 from overheating.

  Further, by providing the protrusions 94a to 97a on the fourth disk 94 to the seventh disk 97, the viscous fluid 60 is difficult to flow, so that the resistance of the main shaft 5a to the viscous fluid 60 is further increased.

5a Main shaft 6 Motor 6a Rotating shaft 60 Viscous fluid 7 Coupling 70 Storage box 71c, 72c, 73c Radiation fin (heat radiation part)
76 elastic part 80 connecting part 81 first connecting board 82 second connecting board 83 third connecting board 84 fourth connecting board 91-93 first disk to third disk (protruding plate)
94-97 4th disk-7th disk (resistance part)

Claims (5)

In a machine tool comprising a main shaft for mounting a tool, a motor for driving the main shaft, and a coupling for connecting the rotation shaft and the main shaft of the motor.
The coupling is
An elastic portion coupled to the rotating shaft;
A connecting part for connecting the elastic part and the main shaft;
A storage box for storing the elastic portion and the connecting portion;
A machine tool, wherein a viscous fluid is injected into the storage box. The machine tool according to claim 1, wherein a resistance portion against the viscous fluid is provided in the connection portion. The resistance portion has a plate shape perpendicular to the main axis,
The machine tool according to claim 2, wherein a protrusion is provided on one surface of the resistance portion. A plurality of the resistance portions are provided,
A plurality of the resistance portions are juxtaposed in the axial direction of the main shaft,
The machine tool according to claim 2, further comprising a protruding plate that protrudes from an inner surface of the housing box in a radial direction of the main shaft and is disposed between the resistance portions. The machine tool according to any one of claims 1 to 4, wherein a heat radiating portion is provided on an outer surface of the storage box.

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