WO2022154040A1

WO2022154040A1 - Main spindle device and method for assembling same

Info

Publication number: WO2022154040A1
Application number: PCT/JP2022/000867
Authority: WO
Inventors: 仁小山内; 真柏原; 剛生有壁
Original assignee: 株式会社小松製作所
Priority date: 2021-01-15
Filing date: 2022-01-13
Publication date: 2022-07-21
Also published as: JP2022109765A

Abstract

This main spindle device comprises a squeeze film damper having: a plurality of seal members spaced apart from one another in the axial direction of a main spindle and compressed and deformed between a bearing unit and a housing; and a viscous fluid between the plurality of seal members, the inner circumferential surface of the housing, and the outer circumferential surface of the bearing unit. The main spindle device further comprises a support member attached to the bearing unit. When elastically deformed, the support member makes contact with the inner circumferential surface of the housing. When not elastically deformed, the support member separates from the inner circumferential surface of the housing.

Description

Main shaft device and its assembly method

The present invention relates to a spindle device and a method for assembling the spindle device.
The present application claims priority with respect to Japanese Patent Application No. 2021-005263 filed in Japan on January 15, 2021, and the contents thereof are incorporated herein by reference.

In spindle devices used in rotating machines such as machine tools, vibration may occur in the spindle due to the inertial force of the spindle. In Patent Document 1, an O-ring is provided between the housing and the spindle unit so as to be separated in the axial direction in order to suppress vibration of the spindle of the cantilever support, and a viscous fluid is filled between the O-rings. A technique for providing a so-called squeeze film damper is disclosed.

Japanese Unexamined Patent Publication No. 5-277806

When a squeeze film damper is provided as in Patent Document 1, it is necessary to support the spindle unit flexibly with respect to the housing and support the spindle unit with respect to the housing so as not to create a gap. On the other hand, if there is no gap between the spindle unit and the housing, it may be difficult to assemble the spindle unit, for example, the spindle unit cannot be inserted into the housing when the spindle unit is assembled to the housing.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a spindle device that can be easily assembled while being able to squeeze the vibration damping well by a squeeze film damper, and an assembling method thereof.

The spindle device according to one aspect of the present invention is a bearing unit provided between a spindle driven to rotate, a housing covering the spindle from the outer peripheral side, and the spindle and the housing, and rotatably supporting the spindle. A plurality of sealing members arranged apart from each other in the axial direction of the main shaft and provided in a state of being compressed and deformed between the bearing unit and the housing, and the inner circumferences of the plurality of sealing members and the housing. A squeeze film damper having a viscous fluid filled between the surface and the outer peripheral surface of the bearing unit, while being attached to the bearing unit and in contact with the inner peripheral surface of the housing when elastically deformed. A support member that is separated from the inner peripheral surface of the housing when it is not elastically deformed is provided.

According to the spindle device of the above aspect, the squeeze film damper enables good vibration damping and can be easily assembled.

It is a perspective view which shows the schematic structure of the machining center in embodiment of this invention. It is sectional drawing of the spindle device in embodiment of this invention. It is sectional drawing of the spindle device which includes a tightening bolt in embodiment of this invention. It is a top view of the support member in embodiment of this invention. It is sectional drawing of the support member along the IV-IV line of FIG. It is a flowchart of the assembly method of the spindle device in embodiment of this invention. It is an exploded sectional view of the spindle device in embodiment of this invention. It is a top view corresponding to FIG. 4 of the support member in the 1st modification of the Embodiment of this invention. It is sectional drawing corresponding to FIG. 5 of the support member in the 1st modification of the Embodiment of this invention. It is a top view corresponding to FIG. 4 of the support member in the 2nd modification of the embodiment of this invention. FIG. 5 is a cross-sectional view corresponding to FIG. 5 of a support member in a second modification of the embodiment of the present invention. It is a top view corresponding to FIG. 4 of the support member in the 3rd modification of the embodiment of this invention. FIG. 5 is a cross-sectional view corresponding to FIG. 5 of a support member in a third modification of the embodiment of the present invention. It is a top view corresponding to FIG. 4 of the support member in the 4th modification of the embodiment of this invention. FIG. 5 is a cross-sectional view corresponding to FIG. 5 of a support member in a fourth modification of the embodiment of the present invention.

<Embodiment>
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 6.
<Machining center>
FIG. 1 is a perspective view showing a schematic configuration of a machining center according to an embodiment of the present invention.
The machining center 80 of the present embodiment includes a base 81, a column 82, a table 83, and a control device 90. The column 82 and the table 83 are provided on the upper surface of the base 81.

The column 82 is provided so as to be movable in the X-axis direction set parallel to the upper surface of the base 81. The base 81 is provided with an X-axis motor 82M and an X-axis encoder 82E. The X-axis motor 82M is an actuator for moving the column 82 along the X-axis. The rotation of the X-axis motor 82M is converted into a linear motion by a ball screw mechanism (not shown). The X-axis encoder 82E measures the amount of movement of the column 82.

A slider 84 is attached to the column 82. The slider 84 is arranged on the side of the column 82 on the table 83 side, and is provided so as to be movable in the Y-axis direction both orthogonal to the X-axis and the Z-axis. The column 82 is provided with a Y-axis motor 84M and a Y-axis encoder 84E. The Y-axis motor 84M is an actuator for moving the slider 84 along the Y-axis. The rotation of the Y-axis motor 84M is converted into a linear motion by a ball screw mechanism (not shown). The Y-axis encoder 84E measures the amount of movement of the slider 84.

The spindle device 1 is attached to the surface of the slider 84 on the table 83 side. The spindle device 1 rotatably supports the spindle 11 around a rotation axis parallel to the Z axis. Tool A is mounted on the spindle 11. Examples of the tool A include a milling cutter and the like. The spindle 11 is provided with a spindle motor 11M for rotating the spindle 11. The tool A is attached to the spindle 11 by the user and can be replaced.

The table 83 is provided so as to be movable in the Z-axis direction parallel to the upper surface of the base 81 and orthogonal to the X-axis. A work table 87 is attached to the upper part of the table 83. The work table 87 is a jig that supports the work W, which is an object to be machined. The base 81 is provided with a Z-axis motor 83M and a Z-axis encoder 83E. The Z-axis motor 83M is an actuator for moving the table 83 along the Z-axis. The rotation of the Z-axis motor 83M is converted into a linear motion by a ball screw mechanism (not shown). The Z-axis encoder 83E measures the amount of movement of the table 83.
The control device 90 controls various actuators of the machining center 80 based on measurement data from various sensors of the machining center 80.

<Spindle device>
FIG. 2 is a cross-sectional view of the spindle device according to the embodiment of the present invention. FIG. 3 is a cross-sectional view of a spindle device including a tightening bolt according to an embodiment of the present invention.
As shown in FIG. 2, the spindle device 1 of the present embodiment includes a housing 12, a bearing unit 13, a squeeze film damper 14, a support member 15, and a tightening mechanism 16. The spindle device 1 of the present embodiment is a cartridge type so that the spindle 11 housed in the housing 12 can be easily replaced. A tool A is attached to and detachable from the spindle 11 of the present embodiment on the left side of FIG. 2, and a spindle motor 11M is linked to the spindle 11 of FIG. In the following description, the direction in which the axis a of the main shaft 11 extends is referred to as the axis direction Da. Further, the radial direction centered on the axis a is referred to as a radial direction Dr, and the circumferential direction centered on the axis a is referred to as a circumferential direction Dc. Further, the left side in FIG. 2 is referred to as an axial one-sided Daf, and the right side in FIG. 2 is referred to as an axially opposite side Dab.

<Housing>
The housing 12 covers the main shaft 11 from the outer peripheral side. Specifically, in the housing 12 of the present embodiment, an opening 21 is formed in Daf on one side in the axial direction, and at least the bearing unit 13 can be taken in and out from the opening 21. The housing 12 of the present embodiment is made of metal and has an inner peripheral surface 22 having a circular cross-sectional shape orthogonal to the axis a at a portion accommodating the bearing unit 13. Further, the housing 12 of the present embodiment includes a flange 24 that closes the opening 21. The flange 24 is formed in a disk shape and has a through hole 23 through which the main shaft 11 penetrates. The flange 24 is connected to the surface 25 on the periphery of the opening 21 facing the Daf on one side in the axial direction by a bolt 26. Further, on the inner peripheral surface 22 of the housing 12, ring grooves 27 continuous in the circumferential direction Dc are formed at intervals in the axial direction Da. An O-ring 43, which will be described later, which is a sealing member, is mounted in the ring groove 27.

<Bearing unit>
The bearing unit 13 is provided between the main shaft 11 and the housing 12 in the radial direction Dr, and rotatably supports the main shaft 11. The bearing unit 13 includes a bearing portion 28 and a holder portion 29.
The bearing portion 28 includes a plurality of ball bearings 31 and a sleeve 32 that positions the plurality of ball bearings 31 in the axial direction Da. The inner ring 33 of the ball bearing 31 rotates together with the main shaft 11, and the outer ring 34 of the ball bearing 31 is in a stationary state. A plurality of balls 35 are held between the inner ring 33 and the outer ring 34. The plurality of ball bearings 31 are arranged at intervals in the axial direction Da, and are integrated by the sleeve 32. In the present embodiment, the case where four ball bearings 31 are provided is shown, but the number of ball bearings 31 provided may be a plurality and is not limited to four.

The holder portion 29 is formed in a cylindrical shape that covers the bearing portion 28 from the outer peripheral side. The holder portion 29 illustrated in this embodiment is formed in a cylindrical shape extending in the axial direction Da. A stationary side portion such as an outer ring 34 constituting the bearing portion 28 described above is fixed to the inner peripheral surface 36 of the holder portion 29 by press fitting or the like. The holder portion 29 is a first end surface 38 which is an outer peripheral surface 37 facing the inner peripheral surface 22 of the housing 12 and two end surfaces 38 extending inward in the radial direction Dr from both outer sides of the outer peripheral surface 37 in the axial direction Da. It has 38A and a second end surface 38B. The outer peripheral surface 37 of the present embodiment has a circular shape in a cross-sectional view orthogonal to the axis a, and extends in the axial direction Da with a constant diameter. The outer peripheral surface 37 forms a predetermined gap S with the inner peripheral surface 22 of the housing 12, except for the portion where the O-ring 43 is arranged. Further, in the holder portion 29 of the present embodiment, a through hole 39 (see FIG. 3) extends over the first end surface 38A of the axial opposite side Dab and the second end surface 38B of the axial direction one side Daf (left side in FIG. 3). Is formed, and a tightening bolt 52, which will be described later, which is a pressing force applying member, is inserted.

The holder portion 29 of the present embodiment has a cylindrical first reduced diameter portion 41 extending from the inside of the radial Dr of the first end surface 38A to the other side Dab in the axial direction. Further, the holder portion 29 has a cylindrical second reduced diameter portion 42 extending from the inside of the second end surface 38B in the radial direction Dr to one side Daf in the axial direction. A support member 15 and a tightening member 51, which will be described later, are arranged on the outer peripheral side of the first reduced diameter portion 41 and the second reduced diameter portion 42.

<Squeeze film damper>
The squeeze film damper 14 attenuates the vibration of the spindle 11 in the radial direction by the so-called squeeze film effect. The squeeze film damper 14 includes a plurality of O-rings 43 and a viscous fluid 44. The squeeze film damper 14 illustrated in the present embodiment includes two O-rings 43, and a damper oil or the like is provided between the two O-rings 43, the inner peripheral surface 22 of the housing 12, and the outer peripheral surface 37 of the bearing unit 13. The viscous fluid 44 is filled. In the housing 12 of the present embodiment described above, in order to inject the viscous fluid 44 into the space between the two O-rings 43, the inner peripheral surface 22 of the housing 12, and the outer peripheral surface 37 of the bearing unit 13, in the radial direction Dr. An injection passage 45 that penetrates is formed. The injection passage 45 is sealed, for example, after the viscous fluid 44 has been injected. The position of the squeeze film damper 14 in the present embodiment is provided in the spindle device 1 at a position where the amplitude due to the vibration of the spindle 11 is large and as wide as possible.

The O-ring 43 is housed in a ring groove 27 formed on the inner peripheral surface 22 of the housing 12. The ring groove 27 is formed in an annular shape centered on the axis a. The O-ring 43 housed in the ring groove 27 is in a state of being compressed and deformed in the radial direction, and seals a gap between the inner peripheral surface 22 of the housing 12 and the holder portion 29 of the bearing unit 13. The two O-rings 43 in the present embodiment are made of rubber or the like, and are arranged at a position close to the first end surface 38A and a position close to the second end surface 38B of the outer peripheral surface 37 of the holder portion 29 in the axial direction Da, respectively. ing. Although the case where the ring groove 27 is provided in the housing 12 has been described, for example, the ring groove 27 may be provided in the holder portion 29.

<Support member>
The support member 15 is attached to the bearing unit 13. The support member 15 comes into contact with the inner peripheral surface 22 of the housing 12 when it is compressed in the axial direction Da by a pressing force equal to or higher than the first pressing force and elastically deformed. On the other hand, the support member 15 is separated from the inner peripheral surface 22 of the housing 12 when the pressing force for compressing in the axial direction Da is less than the first pressing force. In other words, when the support member 15 is crushed in the axial direction Da by the tightening mechanism 16 described later, the support member 15 is elastically deformed so as to expand the diameter at least outward in the radial direction Dr, and comes into contact with the inner peripheral surface 22 of the housing 12. It becomes a state.

The support member 15 of this embodiment is made of synthetic resin. As the synthetic resin, for example, polyamide, polyacetal, or the like can be used. The support member 15 is not limited to synthetic resin, but is a material softer than the holder portion 29 and the tightening ring of the tightening mechanism 16 described later (in other words, a material having a low Young's modulus and easily deformed elastically) and an O-ring. Any material harder than 43 (in other words, a material having a high Young's modulus and not easily elastically deformed) may be used. That is, the first pressing force can be set according to the size of the gap between the support member 15 and the housing 12 in the radial direction, the Young's modulus of the material forming the support member 15, and the like.

FIG. 4 is a plan view of the support member according to the embodiment of the present invention. FIG. 5 is a cross-sectional view of the support member taken along the line IV-IV of FIG.
As shown in FIGS. 4 and 5, the support member 15 is formed in a ring shape centered on the axis a. The support member 15 has a main body 47 formed in an annular shape having a rectangular cross section, a plurality of radial protrusions 48 protruding outward from the main body 47 in the radial direction, and an axial Da from the main body 47. It includes a plurality of axially projecting portions 49 that project toward the direction. A plurality of support members 15 of the present embodiment are provided at intervals in the axial direction Da.

Four radial protrusions 48 in the present embodiment are provided around the axis a at intervals of 90 °. The rigidity of the support member 15 increases as the number of these radial protrusions 48 increases. In the present embodiment, the case where the dimension of the radial protrusion 48 in the axial Da is equivalent to the dimension of the main body 47 in the axial Da is illustrated.
Each of the axially projecting portions 49 is formed at the position of the root of the radially projecting portion 48, and extends in the circumferential direction Dc when viewed from the axial direction Da. The dimension of the axial protrusion 49 in the axial Da is smaller than the dimension of the main body 47 in the axial Da, and the dimension of the axial protrusion 49 in the circumferential Dc is the dimension of the radial protrusion 48 in the circumferential Dc. It is formed larger than the dimensions. Further, in the circumferential direction Dc, the positions of the center O1 of the radial protrusion 48 and the center O2 of the axial protrusion 49 are the same. By providing these axial protrusions 49, the radial protrusion 48 comes into contact with the tightening member 51 before the main body 47 when pressed in the axial direction Da by the tightening member 51 described later. Therefore, a pressing force is preferentially applied to the position of the root of the radial protrusion 48 to elastically deform, and the radial protrusion 48 is displaced to the outside of the radial Dr and brought into contact with the inner peripheral surface 22 of the housing 12. Is possible.

As shown in FIGS. 2 and 3, the spindle device 1 has, as a plurality of support members 15, a first support member 15A in contact with the first end surface 38A of the holder portion 29 and a second support member 15B in contact with the second end surface 38B. And, including. In this embodiment, the case where the outer diameter of the main body 47 of the first support member 15A and the outer diameter of the main body 47 of the second support member 15B are the same is illustrated. However, the outer diameter of the main body 47 of the first support member 15A and the outer diameter of the main body 47 of the second support member 15B are not limited to the same. For example, each main body 47 may have a different outer diameter, such as making the outer diameter of the main body 47 of the second support member larger than the outer diameter of the main body 47 of the first support member 15A.

<Tightening mechanism>
The tightening mechanism 16 presses the support member 15 in the axial direction Da. The tightening mechanism 16 includes a tightening member 51 and a tightening bolt 52.
As shown in FIG. 3, the tightening member 51 is provided so as to sandwich the support member 15 with the bearing unit 13 in the axial direction Da. A plurality of tightening members 51 of the present embodiment are provided at intervals in the axial direction Da. The tightening member 51 of the present embodiment is formed in a ring shape centered on the axis a. The tightening member 51 illustrated in the present embodiment has a rectangular shape in a cross section including the axis a, and has a plane 53 facing the end surface 38 on the side close to the end surface 38 of the holder portion 29 in the axis direction Da. The tightening member 51 in the present embodiment has a flat surface 53, and exemplifies a case where the flat surface 53 has an area equivalent to that of the end face 38. However, the shape of the support member 15 is not limited to a flat surface as long as it can be compressed and deformed, and the area of the flat surface 53 is not limited to the same as the area of the end face 38.

In the present embodiment, the plurality of tightening members 51 include a first tightening member 51A arranged on the other side Dab in the axial direction and a second tightening member 51B arranged on the one side Daf in the axial direction. The first tightening member 51A sandwiches the first support member 15A between the first end surface 38A, and the second tightening member 51B sandwiches the second support member 15B between the second end surface 38B. The first tightening member 51A is arranged on the other side Dab in the axial direction from the first end surface 38A, and has a screw hole 54 extending in the axial direction Da. The screw hole 54 is opened at least on one side Daf in the axial direction. The second tightening member 51B is arranged on one side Daf in the axial direction with respect to the second end surface 38B, and has a through hole 55 penetrating in the axial direction Da.

The tightening bolt 52 extends in the axial direction Da and applies a pressing force for pressing the support member 15 to the tightening member 51. The tightening bolt 52 of the present embodiment applies a pressing force for pressing the first supporting member 15A to the first tightening member 51A and a pressing force for pressing the second supporting member 15B to the second tightening member 51B. Give. The tightening bolt 52 has a head portion 56 provided on one side Daf in the axial direction, and a shaft portion 57 extending from the head head 56 toward the other side Dab in the axial direction. The shaft portion 57 in the present embodiment extends outside the radial direction Dr from the main body portion 47 of the support member 15 described above in the axial direction Da.

A male screw 58 that can be screwed into the screw hole 54 of the first tightening member 51A is formed at least at the tip of the shaft portion 57 located on the other side Dab in the axial direction. The first tightening member 51A is screwed to the shaft portion 57 of the tightening bolt 52.
On the other hand, the shaft portion 57 of the tightening bolt 52 is inserted into the through hole 55 of the second tightening member 51B on the side close to the head portion 56. The through hole 55 is formed to have a diameter larger than that of the shaft portion 57 of the tightening bolt 52. In the present embodiment, the surface 60 of the second tightening member 51B facing the axial one-side Daf is in contact with the surface 59 of the head 56 facing the axial other-side Dab, and the second tightening is performed by the head 56. The member 51B can be pressed against the other Dab in the axial direction.

<Other configurations of bearing unit>
In addition to the above configuration, the bearing unit 13 in the present embodiment further includes a lid member 61 and a seat member 63.
The lid member 61 is formed in a disk shape that covers the above-mentioned second tightening member 51B from one side Daf in the axial direction. The lid member 61 is fixed to the holder portion 29 by a plurality of fixing bolts 64 (see FIG. 2) provided at intervals in the circumferential direction Dc. These fixing bolts 64 are arranged at positions deviated from the above-mentioned tightening bolts 52 in the circumferential direction Dc. The lid member 61 is formed with a tool insertion hole into which a tool such as a hexagon wrench for rotating the head 56 of the tightening bolt 52 can be inserted in the axial direction Da. The lid member 61 is formed so as not to come into contact with the tightening bolt 52 in a state of being connected to the holder portion 29 by the fixing bolt 64. The flange 24 of the present embodiment described above has a similar tool insertion hole 66 on an extension line of the tool insertion hole 65 of the lid member 61, and the flange 24 is attached to the housing 12. Also, the tightening bolt 52 can be rotated through the tool insertion hole 66 of the flange 24 and the tool insertion hole 65 of the lid member 61.

The sheet member 63 is formed in the shape of a sheet made of rubber or the like. The seat member 63 is provided between the end portion 67 of the tab on the other side in the most axial direction of the holder portion 29 and the bottom portion 68 of the housing 12. The seat member 63 is provided between the lid member 61 and the flange 24 in addition to the space between the end portion 67 and the bottom portion 68. These seat members 63 prevent a space from being formed between the flange 24 and the bearing unit 13 and between the bearing unit 13 and the bottom portion 68 of the housing 12, and prevent the bearing unit 13 from being displaced in the axial direction Da. is doing. Further, since the sheet member 63 is formed of rubber or the like and can be elastically deformed in the radial direction, it does not hinder the elastic deformation of the support member 15.

<How to assemble the spindle device>
Next, a method of assembling the spindle device 1 having the above-described configuration will be described with reference to the drawings. FIG. 6 is a flowchart of a method of assembling the spindle device according to the embodiment of the present invention. FIG. 7 is an exploded cross-sectional view of the spindle device according to the embodiment of the present invention.
As shown in FIG. 6, the method of assembling the spindle device 1 in the present embodiment includes at least an O-ring mounting step S01, a bearing unit insertion step S02, and a support member compression step S03. In the description of the method of assembling the spindle device 1 of the present embodiment, the support member 15 and the tightening mechanism 16 are attached to the bearing unit 13 in advance.

As shown in FIGS. 6 and 7, in the O-ring mounting step S01, the O-ring 43 is mounted on the inner peripheral surface 22 of the housing 12 or the outer peripheral surface 37 of the bearing unit 13. In the present embodiment, since the ring groove 27 is formed in the housing 12, the case where the O-ring 43 is mounted on the inner peripheral surface 22 of the housing 12 is illustrated. In the present embodiment, as described above, the two O-rings 43 are mounted on the housing 12 at intervals in the axial direction Da.

In the bearing unit insertion step S02, the bearing unit 13 is inserted into the housing 12 in a state where the pressing force in the axial direction Da acting on the support member 15 is less than the first pressing force. More specifically, the bearing unit 13 is inserted through the opening 21 of the housing 12 facing the Daf on one side in the axial direction. At the time of this insertion, the bearing unit 13 is inserted into the housing 12 from one side Daf in the axial direction in a posture in which the center line of the housing 12 and the center line of the bearing unit 13 are arranged on the same straight line including the axis a. do. Further, in the bearing unit insertion step S02 of the present embodiment, the opening 21 of the housing 12 into which the bearing unit 13 is inserted is closed by the flange 24. In this embodiment, the case where the spindle 11 is inserted together with the bearing unit 13 is illustrated, but the insertion of the bearing unit 13 into the housing 12 does not have to be performed together with the spindle 11.

In the support member compression step S03, with the bearing unit 13 inserted in the housing 12, the pressing force in the axial direction Da acting on the support member 15 is set to be equal to or higher than the first pressing force. Specifically, a tool (not shown) is inserted through the tool insertion hole 66 of the flange 24 and the tool insertion hole 65 of the lid member 61, and the head 56 of the tightening bolt 52 is rotated to support the support member 15. (More specifically, the first support member 15A and the second support member 15B) are subjected to a pressing force equal to or higher than the first pressing force. As a result, the pressing force equal to or higher than the first pressing force can be applied evenly to the first supporting member 15A and the second supporting member 15B, which are the two supporting members 15. Then, the first support member 15A and the second support member 15B are elastically deformed, and the radial protrusions 48 of the first support member 15A and the second support member 15B are in contact with the inner peripheral surface 22 of the housing 12. become.
After that, the viscous fluid 44 is injected through the injection passage 45 of the housing 12 and the injection passage 45 is sealed to complete the assembly of the spindle device 1.

Here, when the radial protrusions 48 of the first support member 15A and the second support member 15B come into contact with the inner peripheral surface 22 of the housing 12, the inner peripheral surface 22 causes the first support member 15A and the second support member 15B to come into contact with each other. Deformation to the outside of Dr in the radial direction is hindered. Therefore, in a state where such deformation to the outside of Dr in the radial direction is hindered, the torque required to rotate the tightening bolt 52 in the tightening direction rapidly increases. The operator can recognize that the pressure is equal to or higher than the first pressing force due to the rapid increase in torque. Therefore, for example, the operator may stop the rotation of the tightening bolt 52 in the tightening direction when he / she recognizes the sudden increase in torque.
Further, in the rotation region after the torque suddenly increases, the inner peripheral surface 22 of the housing 12 is pressed by the first support member 15A and the second support member 15B by increasing or decreasing the amount of rotation for tightening the tightening bolt 52. The pressing force can be changed. Therefore, the damping force of the squeeze film damper 14 can be adjusted by adjusting the amount of rotation of the tightening bolt 52.

<Effect>
As described above, the spindle device 1 of the present embodiment includes a spindle 11, a housing 12, a bearing unit 13, a squeeze film damper 14, and a support member 15. The support member 15 is attached to the bearing unit 13 and comes into contact with the inner peripheral surface 22 of the housing 12 when it is compressed in the axial direction Da by a pressing force equal to or higher than the first pressing force and elastically deformed. On the other hand, the support member 15 is separated from the inner peripheral surface 22 of the housing 12 when the pressing force for compressing in the axial direction Da is less than the first pressing force.
Therefore, when the bearing unit 13 is inserted into the housing 12, a gap is formed between the housing 12 and the support member 15 by making the pressing force of the axial Da on the support member 15 less than the first pressing force. be able to. Therefore, the bearing unit 13 can be smoothly inserted into the housing 12. Further, after the bearing unit 13 is inserted into the housing 12, the support member 15 is brought into contact with the inner peripheral surface 22 of the housing 12 by setting the pressing force of the axial Da on the support member 15 to be equal to or higher than the first pressing force. be able to. Therefore, it is possible to prevent the bearing unit 13 from being displaced more than necessary in the radial direction with respect to the housing 12. As a result, the squeeze film damper 14 enables good vibration damping and can be easily assembled.

In the present embodiment, the support member 15 is further formed of synthetic resin. Therefore, it can be supported softer than the housing 12 made of metal or the like, and can be supported harder than the rubber O-ring 43. Therefore, while stabilizing the posture of the bearing unit 13, it is possible to prevent the support member 15 from becoming too rigid and hindering the vibration damping by the squeeze film damper 14, as in the case where the support member 15 is made of metal.

In the present embodiment, a tightening mechanism 16 for pressing the support member 15 in the axial direction Da is further provided. The tightening mechanism 16 has a tightening member 51 provided so as to sandwich the support member 15 with the bearing unit 13 in the axial direction Da, and presses the support member 15 against the tightening member 51 extending in the axial direction Da. It is provided with a tightening bolt 52 for applying a pressing force. As a result, by simply turning the tightening bolt 52, a pressing force is applied to the tightening member 51 provided so as to be sandwiched between the tightening member 51 and the bearing unit 13, and compression deformation can be performed. Therefore, it is possible to easily apply a pressing force equal to or higher than the first pressing force to the support member 15.

In the present embodiment, the bearing unit 13 further includes a holder portion 29 and a bearing portion 28. The holder portion 29 has an outer peripheral surface 37 that is in contact with the O-ring 43 and extends in the axial direction Da, and an end surface 38 that is located outside the axial direction Da from the position of the O-ring 43 and extends in a direction intersecting the axial line a. It is formed in a cylindrical shape. The support member 15 is sandwiched between the end surface 38 of the holder portion 29 and the tightening member 51. Therefore, by pressing the support member 15 toward the end face 38 side by the tightening member 51, the support member 15 can be elastically deformed and the support member 15 can be projected outward in the radial direction. Therefore, since the end surface 38 of the holder portion 29 can be effectively used as the support surface for sandwiching the support member 15, it is possible to suppress an increase in the number of parts as compared with the case where a new support surface is provided.

In the present embodiment, the housing 12 further has an opening 21 on one side Daf in the axial direction in which the bearing unit 13 can be taken in and out. The tightening bolt 52 has a head portion 56 provided on one side Daf in the axial direction, and a shaft portion 57 extending from the head head 56 toward the other side Dab in the axial direction. The holder portion 29 has a through hole 39 through which the tightening bolt 52 is passed, a first end surface 38A that faces the other side Dab in the axial direction as an end surface 38, and a second end surface 38B that faces the one side Daf in the axial direction. There is. A plurality of tightening members 51 and support members 15 are provided at intervals in the axial direction Da, and the plurality of tightening members 51 are arranged on the other side Dab in the axial direction from the first end surface 38A, and the tightening bolts 52 The first tightening member 51A having a screw hole 54 that is screwed to the shaft portion 57 of the above, and the first tightening member 51A that is arranged on one side Daf in the axial direction from the second end surface 38B and more than the shaft portion 57 of the tightening bolt 52. It includes a second tightening member 51B which is formed to have a large diameter and has a through hole 55 through which the shaft portion 57 penetrates. The plurality of support members 15 are sandwiched between the first support member 15A sandwiched between the first tightening member 51A and the first end surface 38A, and between the second tightening member 51B and the second end surface 38B. The second support member 15B and the like are included. Therefore, by rotating one tightening bolt 52, the first tightening member 51A and the second tightening member 51B are simultaneously displaced, and the first support member 15A and the second support member 15B are evenly compressed. Can be done. Further, by simply rotating the head 56 of the tightening bolt 52, not only the first support member 15A on the one side Daf in the axial direction but also the second support member 15B arranged on the other side Dab in the axial direction is compressed and deformed. Can be done. Therefore, the first support member 15A and the second support member 15B can be easily brought into contact with the housing 12.

The method of assembling the spindle device 1 of the present embodiment includes an O-ring mounting step S01, a bearing unit insertion step S02, and a support member compression step S03. Therefore, the bearing unit 13 can be inserted into the housing 12 with a gap formed between the support member 15 attached to the bearing unit 13 and the housing 12. Further, after the bearing unit 13 is inserted into the housing 12, the support member 15 can be compressed and deformed in the axial direction Da to bring the support member 15 into contact with the housing 12. Therefore, it is possible to reduce the burden on the operator when inserting the bearing unit 13 into the housing 12, and it is also possible to prevent damage to the parts due to an excessive external force at the time of insertion. Further, after the bearing unit 13 is inserted into the housing 12, the posture of the bearing unit 13 can be stabilized and the squeeze film damper 14 can satisfactorily dampen the vibration.

<Other Embodiments>
For example, the shape of the support member 15 is not limited to that described in the above-described embodiment. Hereinafter, first to fourth deformation examples of the support member 15 in the present embodiment will be described with reference to the drawings. In these first to fourth modified examples, the same components as those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

<First modification>
FIG. 8 is a plan view corresponding to FIG. 4 of the support member in the first modification of the embodiment of the present invention. FIG. 9 is a cross-sectional view corresponding to FIG. 5 of the support member in the first modification of the embodiment of the present invention.
As shown in FIGS. 8 and 9, the support member 115 in the first modification is made of a material softer than the holder portion 29 and the tightening ring of the tightening mechanism 16 as in the support member 15 of the above-described embodiment. In other words, it is made of a material that has a low Young's modulus and is easily elastically deformed) and that is harder than the O-ring 43 (in other words, a material that has a high Young's modulus and is not easily elastically deformed). That is, the support member 115 in the first modified example can also be formed of synthetic resin (hereinafter, the same applies to the second modified example to the fourth modified example).

The support member 115 is formed in a ring shape centered on the axis a. The support member 115 includes a main body 47 formed in an annular shape having a rectangular cross section, and a plurality of radial protrusions 148 protruding inward from the main body 47 in the radial direction. The end portion inside the radial direction Dr of the radial direction protrusion 148 is formed so as to face the peripheral surface of the holder portion 29 located inside the radial direction of the support member 115 with a slight gap. Similar to the above-described embodiment, a plurality of support members 115 of this first modification are provided at intervals in the axial direction Da. The support member 115 of this first modification does not have a configuration corresponding to the axially protruding portion 49 of the above-described embodiment.

According to the support member 115 of the first deformation example, when the main body portion 47 is elastically deformed by being compressed by a pressing force equal to or higher than the first pressing force in the axial direction Da, the main body portion 47 comes into contact with the inner peripheral surface 22 of the housing 12 all around. Can be made to. Since the main body 47 can be arranged outside the radial Dr from the radial protrusion 148, it can be applied even when the tightening bolt 52 is located inside the radial Dr from the above-described embodiment. Become. The support member 115 of the first modification has the same support rigidity as the support member 15 of the above-described embodiment. Further, depending on the required characteristics, an axial protrusion 49 may be provided at the base of the radial protrusion 148, similarly to the support member 15 described above.

<Second modification>
FIG. 10 is a plan view corresponding to FIG. 4 of the support member in the second modification of the embodiment of the present invention. FIG. 11 is a cross-sectional view corresponding to FIG. 5 of the support member in the second modification of the embodiment of the present invention. The support member 215 in this second modification has higher support rigidity than the support member 15 of the above-described embodiment.

As shown in FIGS. 10 and 11, the support member 215 in the second modification is formed in a ring shape centered on the axis a, similarly to the support member 15 of the above-described embodiment. The support member 215 has a main body 47 formed in an annular shape having a rectangular cross section, a plurality of radial protrusions 248 protruding outward from the main body 47 in the radial direction, and an axial Da from the main body 47. It includes a plurality of axially projecting portions 249 that project toward the direction. Similar to the above-described embodiment, a plurality of support members 215 of this second modification are also provided at intervals in the axial direction Da.

The basic configuration of the radial protrusion 248 and the axial protrusion 249 in this second modification is the same as that of the radial protrusion 48 and the axial protrusion 49 of the above-described embodiment. The radial Dc of the radial protrusion 248 of the second modification is enlarged in the circumferential direction Dc in order to increase the support rigidity as compared with the radial protrusion 48 of the above-described embodiment. Further, the dimension of the circumferential Dc of the axial protrusion 249 is also expanded according to the dimension of the circumferential Dc of the radial protrusion 248.
According to the support member 215 of the second modification, the support rigidity can be increased as compared with the support member 15 of the above-described embodiment without providing five or more radial protrusions 248 and five or more axial protrusions 249.

<Third modification example>
FIG. 12 is a plan view corresponding to FIG. 4 of the support member in the third modification of the embodiment of the present invention. FIG. 13 is a cross-sectional view corresponding to FIG. 5 of the support member in the third modification of the embodiment of the present invention. The support member 315 in the third modification increases the support rigidity when the shaft portion 57 of the tightening bolt 52 passes inside Dr in the radial direction as in the support member 115 in the first modification described above. It is a thing.
As shown in FIGS. 12 and 13, the support member 15 in the third modification is formed in a ring shape centered on the axis a, similarly to the support member 115 in the first modification described above. The support member 315 includes a main body portion 347 formed in an annular shape having a rectangular cross section, and a plurality of axially projecting portions 349 protruding from the main body portion 347 in the axial direction Da. Similar to the above-described embodiment, a plurality of support members 315 of this third modification are also provided at intervals in the axial direction Da. The support member 315 of this third modification does not have a configuration corresponding to the axially protruding portion 49 of the above-described embodiment.

The main body 347 of the support member 315 of the third modification has the same outer diameter as the main body 47 of the first modification, but has an inner diameter smaller than that of the main body 47 of the first modification. Have. The inner peripheral surface 347a of the main body 347 is located inside the radial Dr from the innermost end of the shaft portion 57 of the tightening bolt 52 in the radial direction, and is a holder located inside the support member 315 in the radial direction. It is formed so as to face the peripheral surface of the portion 29 with a slight gap. The main body portion 347 further has a plurality of recesses 347b for avoiding the shaft portion 57. The recess 347b is recessed from the inner peripheral surface 347a toward the outside in the radial direction. The shaft portion 57 of the tightening bolt 52 passes through the recess 347b in the axial direction Da. The shaft portion 57 and the recessed portion 347b of the tightening bolt 52 are arranged around the axis line a at intervals of 90 °.

Axial protrusions 349 are formed between adjacent recesses 347b in the circumferential direction Dc. The axially projecting portion 349 extends in the circumferential direction Dc when viewed from the axial direction Da, similarly to the axially projecting portion 49 of the embodiment. The dimension of the axial protrusion 349 in the axial direction Da is smaller than the dimension of the main body portion 347 in the axial direction Da. Further, the dimension of the axial protrusion 349 in the circumferential direction Dc is smaller than the distance between the recesses 347b adjacent to each other in the circumferential direction Dc. The axially projecting portion 349 illustrated in the third modification is formed so as to be separated from the recess 347b by a distance equivalent to the width dimension of the recess 347b in the circumferential direction Dc. Further, the axially protruding portion 349 is located on the side of the main body portion 347 close to the inner peripheral surface 347a.

According to the support member 315 of the third modification, the tightening bolt 52 can be applied even when the tightening bolt 52 is located inside the radial Dr as compared with the above-described embodiment, as in the first modification. Further, the main body portion 347 can be made thicker than the main body portion 47 of the first modification. Therefore, the support rigidity can be increased as compared with the support member 115 of the first modification. Further, since the axially protruding portion 349 is provided between the plurality of shaft portions 57 in the circumferential direction Dc, the portion of the main body portion 347 between the plurality of shaft portions 57 in the circumferential direction Dc is tightened by the tightening mechanism. 16 makes it possible to preferentially elastically deform.

<Fourth modification>
FIG. 14 is a plan view corresponding to FIG. 4 of the support member in the fourth modification of the embodiment of the present invention. FIG. 15 is a cross-sectional view corresponding to FIG. 5 of the support member in the fourth modification of the embodiment of the present invention. The support member 415 in the fourth modification has a configuration in which the shaft portion 57 of the tightening bolt 52 is arranged inside the main body portion 447 in the radial direction Dr, and is similar to the support member 15 in the first modification described above. In addition, the radial projecting portion 448 is formed so as to project outward of the radial Dr.

As shown in FIGS. 14 and 15, the support member 415 in the fourth modification is formed in a ring shape centered on the axis a, similarly to the support member 115 in the first modification described above. The support member 415 has a main body 447 formed in an annular shape having a rectangular cross section, a plurality of radial protrusions 448 protruding outward from the main body 447 in the radial direction, and an axial Da from the main body 447. It is provided with a plurality of axially projecting portions 449 that project vertically. The inner peripheral surface 447a inside the radial Dr of the main body 447 of the support member 415 is formed in an arc shape facing the peripheral surface of the holder portion 29 arranged inside the radial Dr of the support member 415. The main body portion 447 has a recess 347b that is recessed from the inner peripheral surface 447a toward the outside of the radial direction Dr, similarly to the main body portion 347 of the third modification. The shaft portion 57 of the tightening bolt 52 passes through the recess 347b in the axial direction Da. The shaft portion 57 and the recessed portion 347b of the tightening bolt 52 are arranged around the axis line a at intervals of 90 °.

The radial protrusion 448 is formed at an intermediate position between the shaft portions 57 of the two tightening bolts 52 adjacent to each other in the circumferential direction Dc. Four radial protrusions 448 in this fourth modification are formed, and each is formed at a position deviated by 45 ° in the circumferential direction Dc with respect to the shaft portion 57 of the tightening bolt 52. Here, the outer peripheral surface 447b of the main body portion 447 is formed by four arc-shaped portions 447 bc formed in an arc shape that is convex toward the outside of the radial direction Dr when viewed from the axial direction Da, and these four arc-shaped portions 447 bc. It is provided with a notch portion 447 bs formed between them and extending linearly.

The arc-shaped portions 447bc are formed with the same arc length, and extend to both sides of the circumferential direction Dc with reference to the position of the shaft portion 57 in the circumferential direction Dc. The radius of curvature of the arcuate portion 447bc is formed to be smaller than the radius of curvature of the inner peripheral surface 22 of the housing 12. That is, the arcuate portion 447bc is formed so as not to come into contact with the inner peripheral surface 22 of the housing 12.

The notch portion 447bs is formed so as to connect the ends of two arcuate portions 447bc adjacent to each other in the circumferential direction Dc with a straight line. The radial protrusion 448 is located at the center of the notch 447bs in the length direction. The radial Dr outer end of the radial protrusion 448 is formed in an arc shape facing the inner peripheral surface 22 of the housing 12 as in the first modification described above, and the support member 415 is axially aligned by the tightening mechanism 16. When compressed in the direction Da, it comes into contact with the inner peripheral surface 22 of the housing 12.

The axial protrusion 449 has the same configuration as the axial protrusion 49 of the above-described embodiment, and is formed at the root position of each of the radial protrusions 448. The axially protruding portion 449 extends in the circumferential direction Dc when viewed from the axial direction Da. The dimension of the axial protrusion 449 in the axial direction Da is smaller than the dimension of the main body portion 447 in the axial direction Da. Further, the dimension of the axial protrusion 449 in the circumferential direction Dc is formed to be larger than the dimension of the radial protrusion 448 in the circumferential direction Dc. Further, in the circumferential direction Dc, the positions of the center O1 of the radial protrusion 448 and the center O2 of the axial protrusion 449 are the same.

According to the support member 415 of the fourth modification, the support rigidity unlike the second modification and the third modification is not required, but the shaft portion 57 of the tightening bolt 52 is formed inside the main body portion 447. In this case, similarly to the support member 15 of the above-described embodiment, the radial protrusion 448 can be elastically deformed so that the radial protrusion 448 comes into contact with the inner peripheral surface 22 of the housing 12.

<Other modifications>
The present invention is not limited to the configuration of the above-described embodiment, and the design can be changed without departing from the gist thereof.
For example,

support members

15, 115, 215, 315, 415,

radial protrusions

48, 148, 248, 448,

axial protrusions

49, 249, 349, 449, tightening members 51, tightening bolts 52, etc. The number of is not limited to the number illustrated in the above-described embodiment and each modification. Further, when a plurality of support members are provided, the

support members

15, 115, 215, 315, 415 of the above-described embodiment and the first to fourth modifications may be used in appropriate combinations.

The case where the axially projecting portion 49 protrudes from the main body portion 47 to one side Daf in the axial direction or the other side in the axial direction has been described, but both sides of the axial direction Da, that is, one side Daf in the axial direction and the other side in the axial direction have been described. It may be made to protrude into each Dab.
Further, in the above-described embodiment, the spindle device 1 used for a machine tool such as a machining center has been described as an example, but it can also be applied to a spindle device used other than a machine tool such as a spindle device used for a construction machine. ..

1 ... Main shaft device 11 ... Main shaft 11M ... Main shaft motor 12 ... Housing 13 ... Bearing unit 14 ... Squeeze film damper 15, 115.215, 315, 415 ... Support member 15A ... First support member 15B ... Second support member 16 ... Tightening Attached mechanism 21 ... Opening 22 ... Inner peripheral surface 23 ... Through hole 24 ... Flange 25 ... Surface 26 ... Bolt 27 ... Ring groove 28 ... Bearing part 29 ... Holder part 31 ... Ball bearing 32 ... Sleeve 33 ... Inner ring 34 ... Outer ring 35 ... ball 36 ... inner peripheral surface 37 ... outer peripheral surface 38 ... end surface 38A ... first end surface 38B ... second end surface 39 ... through hole 41 ... first diameter reduction part 42 ... second diameter reduction part 43 ... O ring 44 ... viscous fluid 45 ... Injection passage 47,347,447 ... Main body 48,148,248,448 ... Radial protrusion 49,249,349,449 ... Axial protrusion 51 ... Tightening member 51A ... First tightening member 51B ... Second tightening member 52 ... Tightening bolt 53 ... Flat surface 54 ... Screw hole 55 ... Through hole 56 ... Head 57 ... Shaft 58 ...

Male screw

59, 60 ... Surface 61 ... Lid member 63 ... Seat member 64 ... Fixing

bolt

65, 66 ... Tool insertion hole 67 ... End 68 ... Bottom 80 ... Machining center 81 ... Base 82 ... Column 82M ... X-axis motor 82E ... X-axis encoder 83 ... Table 83M ... Z-axis motor 83E ... Z-axis encoder 84 ... Slider 84M ... Y-axis motor 84E ... Y-axis encoder 87 ... Work table A ... Tool W ... Work

Claims

Rotationally driven spindle and
A housing that covers the main shaft from the outer peripheral side,
A bearing unit provided between the spindle and the housing and rotatably supporting the spindle,
A plurality of sealing members arranged apart from each other in the axial direction in which the axes of the main shaft extend and provided in a state of being compressively deformed between the bearing unit and the housing, and a plurality of the sealing members and the housing. A squeeze film damper having a viscous fluid between the inner peripheral surface and the outer peripheral surface of the bearing unit, and
A spindle device that is attached to the bearing unit and includes a support member that comes into contact with the inner peripheral surface of the housing when elastically deformed, while being separated from the inner peripheral surface of the housing when not elastically deformed.
Further provided with a tightening mechanism for pressing the support member in the axial direction,
The tightening mechanism
A tightening member provided so as to sandwich the support member between the bearing unit and the bearing unit in the axial direction.
The spindle device according to claim 1, further comprising a pressing force applying member extending in the axial direction to apply a pressing force to press the supporting member to the tightening member.
The bearing unit is
A cylindrical holder portion having an outer peripheral surface that is in contact with the seal member and extends in the axial direction, and an end surface that is located outside the position of the seal member in the axial direction and extends in a direction that intersects the axis. ,
A bearing portion in which an outer ring is fixed to the inner peripheral surface of the holder portion is provided.
The spindle device according to claim 2, wherein the support member is sandwiched between an end face of the holder portion and the tightening member.
The spindle device according to claim 3, wherein the support member is made of a material softer than the holder portion and the tightening member.
The spindle device according to any one of claims 1 to 4, wherein the support member is made of a synthetic resin.
The housing has an opening on one side in the axial direction in which the bearing unit can be taken in and out.
The pressing force applying member has a head provided on one side in the axial direction and a shaft portion extending from the head toward the other side in the axial direction.
The holder portion has a penetrating portion that penetrates the pressing force applying member, a first end surface that faces the other side in the axial direction as the end surface, and a second end surface that faces one side in the axial direction.
A plurality of the tightening member and the support member are provided at intervals in the axial direction.
The plurality of the tightening members
A first tightening member which is arranged on the other side in the axial direction from the first end surface and has a screw hole which is connected to the shaft portion of the pressing force applying member by a screw action.
A second tightening member arranged on one side in the axial direction from the second end surface, formed having a diameter larger than that of the shaft portion of the pressing force applying member, and having a through hole through which the shaft portion penetrates. And, including
The plurality of the support members
A first support member sandwiched between the first tightening member and the first end surface,
The spindle device according to claim 4, further comprising a second support member sandwiched between the second tightening member and the second end surface.
Rotationally driven spindle and
A housing that covers the main shaft from the outer peripheral side,
A bearing unit provided between the spindle and the housing and rotatably supporting the spindle,
A plurality of sealing members arranged apart from each other in the axial direction of the main shaft and provided in a state of being compressively deformed between the bearing unit and the housing, and a plurality of sealing members and the inner peripheral surface of the housing. A squeeze film damper having a viscous fluid between the bearing unit and the outer peripheral surface of the bearing unit.
A support member attached to the bearing unit and in contact with the inner peripheral surface of the housing when elastically deformed in the axial direction, while being separated from the inner peripheral surface of the housing when not elastically deformed.
It is a method of assembling a spindle device equipped with
A seal member mounting step of mounting the seal member on the inner peripheral surface of the housing or the outer peripheral surface of the bearing unit.
A bearing unit insertion step of inserting a bearing unit into the housing in a state where the pressing force acting on the support member in the axial direction is less than the first pressing force.
A method for assembling a spindle device, comprising a support member compression step of making the pressing force in the axial direction acting on the supporting member equal to or higher than the first pressing force in a state where the bearing unit is inserted into the housing.
In the support member compression step,
The method for assembling a spindle device according to claim 7, wherein a pressing force equal to or higher than the first pressing force is applied to the supporting member by rotating the pressing force applying member extending in the axial direction.
In the support member compression step,
By increasing or decreasing the amount of rotation of the pressing force applying member in the rotation region of the pressing force applying member that applies a pressing force equal to or higher than the first pressing force to the supporting member, the damping force by the squeeze film damper can be adjusted. The method for assembling a spindle device according to claim 8.