JP2015094382A - Bearing device, attachment, and machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device in which performance degradation is restrained.SOLUTION: A bearing device comprises: a first race; a second race that can move relatively to the first race; rolling elements arranged between the first race and the second race; and an adjusting device that includes driving devices for applying force to the rolling elements via at least one of the first race and the second race and adjusts bearing rigidity by adjusting the force applied to the rolling elements.

Description

  The present invention relates to a bearing device, an attachment, and a machine tool.

  2. Description of the Related Art A machine tool for machining an object to be machined is known in which an attachment including a tool is detachably attached. The attachment needs to turn, for example, to change the orientation of the tool. Therefore, the attachment includes a bearing device as disclosed in Patent Document 1 and Patent Document 2.

JP 05-212646 A JP-A-11-090782

  If the bearing device has insufficient bearing rigidity, for example, there is a possibility that the positioning accuracy of the tool due to the attachment may be reduced or vibration may occur. For example, when machining a workpiece using a tool, if the bearing rigidity of the bearing device is not sufficient, the positioning accuracy of the tool may be lowered, and the machining accuracy may be lowered. In order to increase the bearing rigidity, a load is applied (preloaded) to the rolling elements of the bearing device in advance. However, when the rolling element is preloaded, the rolling element is always subjected to a force, so that the performance of the bearing device may decrease.

  An object of the present invention is to provide a bearing device, an attachment, and a machine tool in which deterioration in performance is suppressed.

  A bearing device according to the present invention is disposed between a first race ring, a second race ring that can move relative to the first race ring, and the first race ring and the second race ring. An adjusting device that includes a rolling element and a driving device that applies force to the rolling element via at least one of the first raceway and the second raceway, and that adjusts the force applied to the rolling element to adjust bearing rigidity. And comprising.

  According to the present invention, since the adjusting device having the drive device that can apply a force to the rolling element via at least one of the first raceway and the second raceway is provided, the force applied to the rolling element is increased. Thus, the bearing rigidity can be increased, and the bearing rigidity can be decreased by reducing the force applied to the rolling elements. Increased bearing rigidity improves rotational accuracy and positioning accuracy. Further, since the bearing rigidity is increased, smearing caused by the sliding of the rolling elements is reduced, and fretting caused by external vibration is prevented. In addition, since the bearing rigidity is increased, the shake of the rotation center is suppressed. On the other hand, when the bearing rigidity is reduced (the load applied to the rolling elements of the bearing device is reduced), the performance of the bearing device is prevented from being deteriorated. Only in scenes where high bearing rigidity is required, such as when high positioning accuracy is required during machining, in situations where high bearing rigidity is not required (when moving the attachment position), the rolling element is applied with force. By reducing the force applied to the rolling elements, it is possible to suppress a decrease in the performance of the bearing device.

  In the bearing device according to the present invention, the adjusting device applies a first force during relative movement between the first raceway ring and the second raceway ring, and is larger than the first force when the relative movement is stopped. A second force may be applied. For example, a decrease in the performance of the bearing device can be suppressed by reducing the force applied to the rolling elements during the relative movement between the first race ring and the second race ring. On the other hand, the bearing rigidity can be increased by increasing the force applied to the rolling elements when the relative movement between the first raceway and the second raceway is stopped.

  In the bearing device according to the present invention, the bearing device includes a spacer member disposed between the rolling element, the first raceway ring, and the second raceway ring so as to contact the surface of the rolling element, The first raceway and the second raceway are changed from one of a state where a gap is formed between the first raceway and the second raceway and the spacer member and a state where no gap is formed to the other. A force may be applied to at least one of the rings. For example, in a scene where high bearing rigidity is not required, it is added to at least one of the first track ring and the second track ring so that a gap is formed between the first track ring and the second track ring and the spacer member. By reducing the force, it is possible to suppress a decrease in the performance of the bearing device. On the other hand, in a scene where high bearing rigidity is required, the force applied to at least one of the first and second race rings is increased so that the first and second race rings and the spacer member come into contact with each other. As a result, the bearing rigidity can be increased. Further, since the contact area between the first and second race rings and the spacer member is large and the contact area between the spacer member and the rolling element is large, high bearing rigidity can be obtained.

  In the bearing device according to the present invention, the first track ring is disposed around a first shaft, the second track ring is disposed around the first track ring, the first track ring and the first track ring. At least one of the two race rings is divided into a first portion and a second portion with respect to a direction parallel to the first axis, and the drive device is parallel to the first axis in the first portion and the second portion. A force can be applied in any direction, and the adjusting device may adjust the bearing rigidity by adjusting the force applied to the first part and the second part. At least one of the first track ring and the second track ring is divided into a first portion and a second portion, and the force applied to the rolling element is smoothly adjusted by applying a force to the first portion and the second portion. be able to.

  In the bearing device according to the present invention, the rolling element is disposed outside the first rolling element with respect to a first rolling element that supports a load in a direction parallel to the first axis and a radial direction with respect to the first axis. And a second rolling element that supports a load in a direction orthogonal to the first axis. By providing the first rolling element that supports the axial load and the second rolling element that supports the radial load, it is possible to maintain high bearing rigidity with little deterioration in accuracy over time. That is, by providing the bearing device with only the rolling element without providing the sliding element in the bearing device, it is possible to increase the life while increasing the bearing rigidity.

  An attachment according to the present invention is an attachment that is detachably attached to a ram of a machine tool, and includes the above-described bearing device.

  According to the present invention, since the performance degradation of the bearing device is suppressed, the performance degradation of the attachment is also suppressed.

  The above-mentioned attachment is attached to the machine tool according to the present invention.

  According to the present invention, since the degradation of the performance of the attachment is suppressed, the degradation of the performance of the machine tool is also suppressed.

  According to the present invention, a decrease in performance is suppressed.

FIG. 1 is a diagram illustrating an example of a machine tool according to the first embodiment. FIG. 2 is a cross-sectional view illustrating an example of the attachment according to the first embodiment. FIG. 3 is a perspective view in which a part of the bearing device according to the first embodiment is broken. FIG. 4 is a side sectional view showing a part of the bearing device according to the first embodiment. FIG. 5 is a schematic diagram illustrating an example of the operation of the drive device according to the first embodiment. FIG. 6 is a diagram showing the relationship between the force applied by the driving device to the first part and the second part, the surface pressure of the rolling element, and the bearing rigidity. FIG. 7 is a view schematically showing a part of the bearing device according to the second embodiment. FIG. 8 is a diagram schematically showing a part of the bearing device according to the second embodiment. FIG. 9 is a side sectional view showing a part of the bearing device according to the second embodiment. FIG. 10 is a schematic diagram illustrating an example of the operation of the drive device according to the second embodiment. FIG. 11 is a diagram illustrating the relationship between the force applied by the driving device to the first part and the second part, the surface pressure of the rolling element, and the bearing rigidity. FIG. 12 is a side sectional view showing a part of the bearing device according to the third embodiment. FIG. 13 is a diagram illustrating an example of the first rolling element according to the third embodiment. FIG. 14 is a diagram illustrating an example of a second rolling element according to the third embodiment.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, the constituent elements in the embodiments described below can be combined as appropriate. Some components may not be used.

  In the following description, an XYZ orthogonal coordinate system is set, and the positional relationship of each part will be described with reference to this XYZ orthogonal coordinate system. One direction in the horizontal plane is defined as the X-axis direction, a direction orthogonal to the X-axis direction in the horizontal plane is defined as the Y-axis direction, and a direction orthogonal to each of the X-axis direction and the Y-axis direction is defined as the Z-axis direction. Further, the rotation (inclination) directions around the X axis, Y axis, and Z axis are the θX, θY, and θZ directions, respectively.

<First Embodiment>
A first embodiment will be described. FIG. 1 is a diagram illustrating an example of a machine tool 1 according to the present embodiment. The machine tool 1 processes a processing object using a tool. The machine tool 1 is a numerically controlled machine tool (machining center) having a function of automatically changing tools and capable of performing different types of machining by one machine according to the purpose.

  The machine tool 1 includes a bed 2, a table 3 supported by the bed 2 so as to be movable in the X-axis direction, a column 4, a saddle 5 supported by the column 4 so as to be movable in the Y-axis direction, and a saddle 5 And a ram 6 supported so as to be movable in the Z-axis direction. An attachment 7 is detachably attached to the tip of the ram 6 of the machine tool 1. The column 4 is a portal column arranged so as to straddle the table 3. In the present embodiment, the machine tool 1 is a so-called portal machine tool. The machine tool 1 is controlled by the control device 10.

  The table 3 is movable while supporting the workpiece. The table 3 is moved by the operation of a driving device including a ball screw mechanism. The ball screw mechanism includes a nut provided on the table 3, a screw shaft disposed in the X-axis direction, and a ball disposed between the screw shaft and the nut. The drive device has a servo motor that rotates the screw shaft of the ball screw mechanism. The table 3 moves in the X-axis direction by the operation of the servo motor.

  The column 4 has a cross rail 8 arranged in the Y-axis direction. The saddle 5 moves in the Y-axis direction while being supported by the cross rail 8. The ram 6 is supported by the saddle 5 so as to be movable in the Z-axis direction. An attachment 7 including a tool 9 is attached to the tip of the ram 6.

  FIG. 2 is a cross-sectional view showing an example of the attachment 7 according to this embodiment. As shown in FIG. 2, the attachment 7 includes a first member 11 that is rotatably supported by the ram 6 (machine tool 1), and a second member 12 that is rotatably supported by the first member 11. The tool 9 is rotatably supported by the second member 12.

  The attachment 7 includes a bearing device 13 disposed between the ram 6 and the first member 11 and a bearing device 14 disposed between the first member 11 and the second member 12. At least a part of the bearing device 13 is supported by the ram 6. At least a part of the bearing device 14 is supported by the first member 11. The first member 11 is rotatable about the C axis while being supported by at least a part of the bearing device 13. The second member 12 is rotatable about the U axis while being supported by at least a part of the bearing device 14. The tool 9 is rotatable around the F axis. In the present embodiment, the C axis and the F axis are substantially parallel. The U axis and the F axis are non-parallel. Note that the C-axis and the F-axis may be non-parallel. The attachment 7 includes a first driving device (not shown) that rotates the first member 11 around the C axis, and a second driving device (not shown) that rotates the second member 12 around the U axis.

  The C axis and the U axis are non-parallel. In the present embodiment, the C axis is parallel to the Z axis. The U axis is non-parallel to each of the X axis, the Y axis, and the Z axis. As described above, the ram 6 is movable in the X-axis direction, the Y-axis direction, and the Z-axis direction. The first member 11 is movable (rotatable) in the θC direction (θZ direction). The second member 12 is movable (rotatable) in the θU direction. The tool 9 is movable (rotatable) in the θF direction. In the present embodiment, the second member 12 and the tool 9 attached to the second member 12 are movable in five directions of X axis, Y axis, Z axis, θC, and θU.

  In the present embodiment, the bearing device 13 and the bearing device 14 have an equivalent structure. Hereinafter, the bearing device 13 will be mainly described.

  FIG. 3 is a perspective view in which a part of the bearing device 13 according to the present embodiment is broken. FIG. 4 is a side sectional view showing a part of the bearing device 13 according to the present embodiment. FIG. 4 corresponds to the AA arrow view of FIG.

  As shown in FIGS. 3 and 4, the bearing device 13 includes a first race ring 21, a second race ring 22 that can move relative to the first race ring 21, and the first race ring 21 and the second race track. A rolling element 23 disposed between the wheel 22 and a driving device 24 that applies a force to the rolling element 23 via at least one of the first raceway ring 21 and the second raceway ring 22, and a force applied to the rolling element 23 And an adjusting device 25 for adjusting the bearing rigidity. The adjusting device 25 is controlled by the control device 10.

  The first track ring 21 is disposed around the C axis. The second track ring 22 is disposed around the first track ring 21. In the following description, the first track ring 21 is appropriately referred to as an inner ring 21, and the second track ring 22 is appropriately referred to as an outer ring 22. The inner ring 21 and the outer ring 22 are relatively rotatable.

  In the present embodiment, the bearing device 13 is a rolling bearing. The rolling element 23 is a roller. A plurality of rolling elements 23 are arranged around the C axis. In the present embodiment, the bearing device 13 is a cross roller bearing. The rotation axis J1 of some of the rolling elements 23 among the plurality of rolling elements 23 is inclined so as to approach the C axis from the + C side toward the −C side. The rotation axis J2 of some of the rolling elements 23 among the plurality of rolling elements 23 is inclined from the C axis toward the −C side from the + C side. The rolling elements 23 of the rotation axis J1 and the rolling elements 23 of the rotation axis J2 are alternately arranged around the C axis.

  The outer ring 22 is divided into a first portion 26 and a second portion 27 with respect to a direction parallel to the C-axis (Z-axis direction). Each of the first portion 26 and the second portion 27 is an annular member disposed around the C axis. The first portion 26 is disposed on the + Z side (+ C side) of the second portion 27.

  The driving device 24 can apply a force to the first portion 26 and the second portion 27 in the Z-axis direction. As shown in FIG. 3, a plurality of driving devices 24 are arranged around the C axis. In the present embodiment, the driving device 24 includes a hydraulic cylinder. As shown in FIG. 4, the drive device 24 includes a cylinder 28, a flange portion 29 </ b> E, and a flange portion 29 </ b> F. At least the flange portion 29 </ b> E is disposed inside the cylinder 28, and the cylinder 28 and the piston 29. A hydraulic pressure adjusting device 31 capable of adjusting the pressure of each of the space 30A and the space 30B by supplying oil (liquid) to each of the space 30A and the space 30B and recovering oil from the space 30A and the space 30B. I have.

  The flange portion 29E is disposed at the upper end portion of the piston 29. The flange portion 29 </ b> F is disposed at the lower end portion of the piston 29.

  The upper end portions of the cylinder 28 and the piston 29 are arranged above the first portion 26 (+ Z direction). The lower end portion of the piston 29 is disposed below the second portion 27 (−Z direction). The lower surface 28F of the cylinder 28 faces the upper surface of the first portion 26. Each of the first portion 26 and the second portion 27 has a through hole in which the piston 29 is disposed. The flange 29 </ b> F is in contact with the lower surface of the second portion 27. The first portion 26 and the second portion 27 are disposed between the lower surface 28F of the cylinder 28 and the flange 29F of the piston 29 with respect to the Z-axis direction.

  The space 30A is a space above the flange portion 29E in the internal space of the cylinder 28. The space 30B is a space below the flange portion 29E in the internal space of the cylinder 28.

  The space 30A is connected to the hydraulic pressure adjusting device 31 via the piping 40A and the piping 41. The space 30B is connected to the hydraulic pressure adjusting device 31 via the pipe 40B and the pipe 41. A valve mechanism (flow path switching mechanism) 42 is disposed in the pipe 41. When the hydraulic pressure adjusting device 31 and the space 30A are connected by the valve mechanism 42 via the piping 41 and the piping 40A, the flow path connecting the hydraulic pressure adjusting device 31 and the space 30B is closed. On the other hand, when the hydraulic adjustment device 31 and the space 30B are connected by the valve mechanism 42 via the piping 41 and the piping 40B, the flow path connecting the hydraulic adjustment device 31 and the space 30A is closed.

  For example, when the flow path connecting the hydraulic pressure adjusting device 31 and the space 30A is closed, the piston 29 moves upward by supplying oil from the hydraulic pressure adjusting device 31 to the space 30B to increase the pressure in the space 30B. To do. On the other hand, when the flow path connecting the hydraulic pressure adjusting device 31 and the space 30B is closed, the piston 29 moves downward by supplying oil from the hydraulic pressure adjusting device 31 to the space 30A and increasing the pressure in the space 30A. To do. The piston 29 may be moved upward by collecting oil from the space 30A and reducing the pressure in the space 30A. The piston 29 may be moved downward by collecting oil from the space 30B and reducing the pressure in the space 30B.

  FIG. 5 is a schematic diagram illustrating an example of the operation of the driving device 24. For example, when the pressure of at least one of the space 30A and the space 30B is adjusted by the operation of the hydraulic pressure adjusting device 31 and the piston 29 moves upward, the lower surface 28F of the cylinder 28 and the flange 29F of the piston 29 are connected to the first portion 26 and the first portion 26. The force sandwiching the two portions 27 is increased. That is, when the piston 29 moves upward, the force in the Z-axis direction applied to the first portion 26 and the second portion 27 disposed between the lower surface 28F and the flange 29F increases. When a force in the Z-axis direction is applied to the first portion 26 and the second portion 27 by the driving device 24 and the first portion 26 and the second portion 27 move so as to approach each other, the force applied to the surface of the rolling element 23 (Pressure) increases. Since the surface of the rolling element 23 is in contact with each of the inner surface (track surface) of the inner ring 21 and the inner surface (track surface) of the outer ring 22, the driving device 24 contacts the first portion 26 and the second portion 27 in the Z-axis direction. When force is applied to, the force (surface pressure) applied to the surface of the rolling element 23 increases. Thereby, bearing rigidity becomes high.

  On the other hand, when the pressure of at least one of the space 30 </ b> A and the space 30 </ b> B is adjusted by the operation of the hydraulic pressure adjusting device 31 and the piston 29 moves downward, the lower surface 28 </ b> F and the cylinder 29 </ b> F sandwich the first portion 26 and the second portion 27. Becomes smaller and the force (surface pressure) applied to the surface of the rolling element 23 becomes smaller. Thus, the control device 10 (adjustment device 25) controls the hydraulic pressure adjustment device 31 to adjust the pressure of at least one of the space 30A and the space 30B, thereby applying Z to the first portion 26 and the second portion 27. The axial force can be adjusted. By adjusting the force in the Z-axis direction applied to the first portion 26 and the second portion 27, the surface pressure of the rolling element 23 is adjusted, and the bearing rigidity is adjusted.

  FIG. 6 shows the relationship between the force applied by the driving device 24 to the first portion 26 and the second portion 27 (the force sandwiching the first portion 26 and the second portion 27), the surface pressure of the rolling element 23, and the bearing rigidity. FIG. In the graph shown in FIG. 6, the horizontal axis is the force applied to the first portion 26 and the second portion 27, and the vertical axis is the surface pressure and the bearing rigidity of the rolling element 23. In the present embodiment, the force applied to the first portion 26 and the second portion 27 correlates with the pressure (hydraulic pressure) in the space 30A and the space 30B.

  As described above, when the force applied to the first portion 26 and the second portion 27 increases and the surface pressure of the rolling element 23 increases, the bearing rigidity increases. On the other hand, when the force applied to the first portion 26 and the second portion 27 is reduced and the surface pressure of the rolling element 23 is reduced, the bearing rigidity is lowered.

  In the present embodiment, the adjusting device 25 applies the first force F1 to the first portion 26 and the second portion 27 during the relative movement between the inner ring 21 and the outer ring 22, and stops the relative movement between the inner ring 21 and the outer ring 22. Sometimes a second force F2 greater than the first force F1 is applied to the first portion 26 and the second portion 27. That is, the controller 10 causes the surface pressure of the rolling element 23 when the relative movement between the inner ring 21 and the outer ring 22 is stopped to be larger than the surface pressure of the rolling element 23 when the inner ring 21 and the outer ring 22 are moved relative to each other. Next, the adjusting device 25 is controlled.

  In the present embodiment, the relative movement between the inner ring 21 and the outer ring 22 is the relative rotation between the inner ring 21 and the outer ring 22 with the C axis as the rotation center, and includes the turning of the first member 11.

  In the present embodiment, when the relative movement between the inner ring 21 and the outer ring 22 is stopped, the relative rotation between the inner ring 21 and the outer ring 22 about the C axis is stopped, and when the turning of the first member 11 is stopped. including. In addition, when machining using the tool 9 is performed when the turning of the first member 11 is stopped, the process of using the tool 9 is included when the relative movement between the inner ring 21 and the outer ring 22 is stopped.

  In addition, the process using the tool 9 may be performed while the 1st member 11 turns (while the inner ring | wheel 21 and the outer ring | wheel 22 rotate relatively). In that case, the adjusting device 25 applies a second force F2 that is larger than the first force F1 when the inner ring 21 and the outer ring 22 move relative to each other.

  By reducing the force applied to the rolling element 23 during the turning of the first member 11, for example, damage to the surface of the rolling element 23 or an increase in the temperature of the rolling element 23 is suppressed. That is, by reducing the surface pressure of the rolling element 23 during the turning of the first member 11, a decrease in performance of the bearing device 13 including the rolling element 23 is suppressed. Further, by reducing the surface pressure of the rolling element 23 during the turning of the first member 11, the inner ring 21 rotates smoothly with respect to the outer ring 22, and the first member 11 can turn smoothly with a small torque. . On the other hand, when the first member 11 is stopped or when machining using the tool 9, the force applied to the rolling elements 23 is increased to increase the bearing rigidity, thereby increasing the positioning accuracy of the tool 9, for example. Become.

  As described above, according to the present embodiment, the bearing rigidity can be adjusted by adjusting the force applied to the rolling elements 23 via the inner ring 21 and the outer ring 22. By increasing the force applied to the rolling elements 23 to increase the bearing rigidity, the rotation accuracy and positioning accuracy of the first member 11 are improved, and vibration and noise are suppressed. Further, by increasing the bearing rigidity, smearing due to the sliding of the rolling elements 23 is reduced, and fretting caused by external vibration is prevented. Further, by reducing the force applied to the rolling elements 23, the bearing device 13 can rotate smoothly. Thus, only in a scene where high bearing rigidity is required, the force applied to the rolling element 23 is increased, and in a scene where high bearing rigidity is not required, the force applied to the rolling element 23 is reduced to achieve high rotational accuracy. Can be obtained. Accordingly, a decrease in performance of the bearing device 13 is suppressed.

  Moreover, in this embodiment, since the 1st force F1 was applied at the time of turning of the 1st member 11, the 1st member 11 can be turned smoothly. Since the second force F2 larger than the first force F1 is applied when the first member 11 is stopped or processed, the bearing rigidity can be increased and the positioning accuracy and processing accuracy can be improved.

  In the present embodiment, the outer ring 22 is divided into the first portion 26 and the second portion 27, and the bearing rigidity is increased by adjusting the force in the Z-axis direction applied to the first portion 26 and the second portion 27. It can be adjusted smoothly.

Second Embodiment
A second embodiment will be described. In the following embodiments, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  7 and 8 are diagrams schematically showing a part of the bearing device 13 according to the present embodiment. In the present embodiment, the bearing device 13 is a ball bearing. That is, in this embodiment, the rolling element 23 is a ball (ball). As in the first embodiment, the rolling element 23 may be a roll.

  In the present embodiment, the bearing device 13 includes a spacer member 32 disposed between the rolling element 23 and the inner ring 21 and the outer ring 22 so as to be in contact with the surface of the rolling element 23. The spacer member 32 is made of metal. As shown in FIG. 7, the spacer member 32 has an inner surface (support surface) 33 that can contact the surface of the rolling element 23. The inner surface 33 is formed along the shape of the surface of the rolling element 23. Thereby, the inner surface 33 can contact the surface of the rolling element 23. In this embodiment, the rolling element 23 is a ball, and the inner surface 33 is formed in a spherical shape so as to follow the shape of the surface of the ball. In addition, when the rolling element 23 is a roll, the inner surface 33 is formed along the shape of the surface of the roll.

  As shown in FIG. 8, the spacer member 32 is disposed between the adjacent rolling elements 23. In the present embodiment, the spacer member 32 has two inner surfaces 33 that can come into contact with the rolling elements 23 on both sides.

  FIG. 9 is a side sectional view showing a part of the bearing device 13 according to the present embodiment. As shown in FIG. 9, the rolling element 23 that is in contact with the spacer member 32 is disposed between the inner ring 21 and the outer ring 22. In a state where the force applied to the first member 26 and the second member 27 is small, a gap G is formed between the spacer member 32 and the inner ring 21 and the outer ring 22 as shown in FIG.

  FIG. 10 is a schematic diagram illustrating an example of the operation of the driving device 24. When the piston 29 moves upward and the force applied to the first portion 26 and the second portion 27 increases, the rolling element 23 is slightly elastically deformed. Thereby, the inner ring | wheel 21 and the outer ring | wheel 22 approach the spacer member 32, and the dimension of the clearance gap G becomes small. When the force applied to the first portion 26 and the second portion 27 is further increased, the inner ring 21 and the outer ring 22 are brought into contact with the side surfaces of the spacer member 32, and the gap G disappears (the size of the gap G becomes zero). On the other hand, when the piston 29 moves downward and the force applied to the first portion 26 and the second portion 27 decreases, the inner ring 21 and the outer ring 22 are separated from the spacer member 32, and a gap G is formed. Thus, in the present embodiment, the driving device 24 changes from one of the state where the gap G is formed between the inner ring 21 and the outer ring 22 and the spacer member 32 and the state where the gap G is not formed to the other. In addition, a force can be applied to at least one of the inner ring 21 and the outer ring 22.

  FIG. 11 is a diagram illustrating the relationship between the force applied by the driving device 24 to the first portion 26 and the second portion 27, the surface pressure of the rolling element 23, and the bearing rigidity. In the graph shown in FIG. 11, the horizontal axis represents the force applied to the first portion 26 and the second portion 27, and the vertical axis represents the surface pressure of the rolling element 23 and the bearing rigidity. In FIG. 11, line L1 is the surface pressure of the rolling element 23, and line L2 is bearing rigidity.

  Similar to the above-described embodiment, also in this embodiment, the first force F1 is applied when the first member 11 turns, and the second force that is greater than the first force F1 when the first member 11 is stopped or processed. A force F2 is applied. In the present embodiment, a force is applied to the first portion 26 and the second portion 27 so that the gap G is formed when the first member 11 is turned. On the other hand, when the first member 11 is stopped or processed, a force is applied to the first portion 26 and the second portion 27 so that the gap G is not formed.

  As shown in FIG. 11, when the force applied to the first portion 26 and the second portion 27 is gradually increased in a state where the gap G is formed, the surface pressure and the bearing rigidity of the rolling element 23 are also gradually increased. growing.

  When the force applied to the first portion 26 and the second portion 27 gradually increases and reaches the force Fg, the inner ring 21 and the outer ring 22 come into contact with the side surfaces of the spacer member 32, and the gap G is eliminated.

  If the force applied to the first portion 26 and the second portion 27 is further increased after the gap G is eliminated, the bearing rigidity is further increased. The surface pressure of the rolling element 23 is only slightly increased because the load is shared by the spacer member 32 and the rolling element 23. In the present embodiment, the contact area between the inner ring 21 and the outer ring 22 and the spacer member 32 is large. Moreover, the contact area of the spacer member 32 and the rolling element 23 is also large. Therefore, high bearing rigidity can be obtained by further increasing the force applied to the first portion 26 and the second portion 27 while the inner ring 21 and the outer ring 22 are in contact with the spacer member 32.

  In the present embodiment, in a scene where the bearing device 13 does not require high bearing rigidity, the driving device 24 operates so that a gap G is formed between the inner ring 21 and the outer ring 22 and the spacer member 32, thereby The bearing device 13 can be smoothly rotated while suppressing a decrease in the performance of the device 13. On the other hand, in a scene where high bearing rigidity is required for the bearing device 13, high bearing rigidity can be obtained by operating the driving device 24 so that the inner ring 21 and the outer ring 22 and the spacer member 32 are in contact with each other.

<Third Embodiment>
A third embodiment will be described. In the following embodiments, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 12 is a side sectional view showing a part of the bearing device 13 according to the present embodiment. In this embodiment, the bearing device 13 is disposed outside the first rolling element 231 with respect to the first rolling element 231 that supports a load in a direction parallel to the C axis (Z axis) and the radial direction with respect to the C axis. And a second rolling element 232 that supports a load in a direction orthogonal to the axis.

  The first rolling element 231 is a roll. In FIG. 12, the rotation axis of the first rolling element 231 and the Y axis are parallel. In the present embodiment, two first rolling elements 231 are arranged in the C-axis direction (Z-axis direction). The inner ring 21 includes a support portion 21 </ b> S that supports the two first rolling elements 231. The support portion 21S functions as a raceway. Of the two first rolling elements 231 arranged in the C-axis direction, the first rolling element 231 on the + Z side is arranged between the support portion 21S and the first portion 26, and is the first rolling element on the −Z side. 231 is disposed between the support portion 21 </ b> S and the second portion 27. The rotation axis of the first rolling element 231 is orthogonal to the C axis.

  The second rolling element 232 includes a roller (roller) of a cross roller bearing. That is, the rotation axis of the second rolling element 232 is inclined with respect to the C axis. The second rolling element 232 is disposed between the support portion 21 </ b> S of the inner ring 21 and the outer ring 22. Similar to the above-described embodiment, the outer ring 22 is divided into a first portion 26 and a second portion 27. The second rolling element 232 is disposed between the support portion 21 </ b> S, the first portion 26, and the second portion 27.

  In this embodiment, the dimension (the length of the roller) of the first rolling element 231 in the direction parallel to the rotation axis of the first rolling element 231 is the second rolling element in the direction parallel to the rotation axis of the second rolling element 232. It is larger than the dimension of 232 (the length of the roller). When the rolling element is a roller, the bearing rigidity depends on the length of the roller.

  The driving device 24 can adjust the surface pressure of the first rolling element 231 and the surface pressure of the second rolling element 232 by applying a force to the first part 26 and the second part 27. The first rolling element 231 receives a force from the driving device 24 acting in the Z-axis direction. The second rolling element 232 maintains the rotation center of the bearing device 13. The bearing rigidity is adjusted by adjusting the surface pressure of the first rolling element 231 and the surface pressure of the second rolling element 232, respectively.

  As described above, according to the present embodiment, the bearing device 13 includes the first rolling element 231 that supports the load in the direction parallel to the C axis and the outside of the first rolling element 231 in the radial direction with respect to the C axis. And a second rolling element 232 that supports a load in a direction orthogonal to the C axis. By providing the first rolling element 231 that supports the axial load and the second rolling element 232 that supports the radial load, it is possible to maintain high bearing rigidity with little deterioration in accuracy over time. That is, by providing the bearing device 13 with only rolling elements without providing the sliding device in the bearing device 13, it is possible to increase the life while increasing the bearing rigidity.

  FIG. 13 is a diagram illustrating an example of the first rolling element 231. As shown in FIG. 13, the first rolling element 231 may be a tapered roller (conical roller).

  FIG. 14 is a diagram illustrating an example of the second rolling element 232. As shown in FIG. 14, the second rolling element 232 may be a roller (roller) whose rotation axis is parallel to the C axis.

  In the first to third embodiments described above, the outer ring 22 is divided into the first portion 26 and the second portion 27, and the driving device 24 applies force to the outer ring 22. The inner ring 21 may be divided into a first part and a second part, and the driving device 24 may apply a force to the inner ring 21.

  In the first to third embodiments described above, the bearing device 13 has been mainly described. The bearing device 14 has the same configuration. The inner ring 21 of the bearing device 14 is disposed around the U-axis, and the outer ring 22 of the bearing device 14 is disposed around the inner ring 21 of the bearing device 14. At least one of the inner ring 21 and the outer ring 22 of the bearing device 14 is divided into a first portion 26 and a second portion 27 in a direction parallel to the U axis. The driving device 24 can apply a force to the first portion 26 and the second portion 27 of the bearing device 14 in a direction parallel to the U axis. When the second member 12 is turned, a first force F1 is applied to the rolling element 23 of the bearing device 14, and when the second member 12 is stopped or processed, the first force F1 is applied to the rolling element 23 of the bearing device 14. A second force F2 that is greater than

DESCRIPTION OF SYMBOLS 1 Machine tool 7 Attachment 9 Tool 10 Control apparatus 13 Bearing apparatus 14 Bearing apparatus 21 1st ring (inner ring)
22 Second race (outer ring)
DESCRIPTION OF SYMBOLS 23 Rolling body 24 Drive apparatus 25 Adjustment apparatus 26 1st part 27 2nd part 32 Spacer member 231 1st rolling element 232 2nd rolling element

Claims (7)

A first track ring;
A second bearing ring movable relative to the first bearing ring;
A rolling element disposed between the first raceway and the second raceway;
A driving device that applies a force to the rolling element via at least one of the first raceway and the second raceway, and an adjustment device that adjusts the force applied to the rolling member to adjust bearing rigidity. Bearing device.   The adjusting device applies a first force during relative movement between the first track ring and the second track ring, and applies a second force larger than the first force when the relative movement is stopped. The bearing device according to 1. A spacer member disposed between the rolling element and the first and second race rings so as to come into contact with the surface of the rolling element;
The drive device is configured to change the first track ring from one of a state in which a gap is formed between the first track ring and the second track ring and the spacer member and a state in which no gap is formed to the other. The bearing device according to claim 1 or 2, wherein a force is applied to at least one of the second race. The first track ring is disposed around a first axis;
The second race is disposed around the first race,
At least one of the first raceway and the second raceway is divided into a first portion and a second portion with respect to a direction parallel to the first axis;
The driving device can apply a force to the first part and the second part in a direction parallel to the first axis,
The said adjustment apparatus is a bearing apparatus as described in any one of Claims 1-3 which adjusts the force added to the said 1st part and the said 2nd part, and adjusts the said bearing rigidity.   The rolling element is disposed outside the first rolling element with respect to a radial direction with respect to the first axis and supports the load in a direction parallel to the first axis, and is orthogonal to the first axis. The bearing device according to claim 4, further comprising a second rolling element that supports a load in a direction. An attachment that is detachably attached to a ram of a machine tool,
An attachment provided with the bearing apparatus as described in any one of Claims 1-5.   A machine tool to which the attachment according to claim 6 is attached.

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