JP3965252B2 - Bearing device and spindle device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bearing device and a spindle device, and more particularly to a bearing technology that rotatably supports a rotating shaft while allowing movement in the axial direction thereof.
[0002]
[Prior art]
For example, in a spindle device for a rotary tool of a machine tool, as shown in FIG. 7 (a), a rotary spindle b on which a rotary tool (not shown) is attached to a tip end a can be rotated by a pair of front and rear bearings c and d. The drive motor e for rotating the rotary main shaft b is integrally incorporated between the bearings c and d.
[0003]
By the way, of the pair of front and rear bearings c and d that rotatably support the rotation main shaft b, the rear bearing d is called a so-called support bearing and can mainly absorb the axial extension of the rotation main shaft b. It has.
[0004]
That is, in a motor built-in spindle device, due to its complicated structure, a dimensional error of 1 mm or more from a predetermined axial dimension is caused by accumulated errors due to assembly or thermal expansion of the rotating spindle b due to heat generated during high-speed rotation. May occur. For this reason, this type of spindle device must have a structure that absorbs changes in the support position of the rotation main shaft b and changes in the axial dimension of the rotation main shaft b, and this rear bearing or support is responsible for this role. Bearing d.
[0005]
For this purpose, a cylindrical roller bearing having a structure as shown in FIG. 7B is conventionally used as the support bearing d.
[0006]
In this cylindrical roller bearing d, the outer race of the inner ring (inner race ring) f includes two rows of race grooves g and g, and the inner race i of the outer race (outer race ring) h has a linear cross section. A plurality of cylindrical rollers j, j,... Are double row cylindrical roller bearings configured to roll on both the tracks g, i. k denotes a retainer for rotatably holding the cylindrical rollers j, j,... at a predetermined interval in the circumferential direction, and l denotes an injection hole for a lubricant provided in the outer ring h.
[0007]
When thermal expansion due to heat generation or the like occurs in the rotary spindle b that is driven to rotate by the drive motor e, axial movement of the cylindrical rollers j, j,. As a result, the relative axial positions of the inner and outer rings f and h change following the change (elongation) in the axial dimension of the rotary spindle b, thereby effectively absorbing the extension of the rotary spindle b. Become.
[0008]
[Problems to be solved by the invention]
However, such a structure of the conventional support bearing d has the following problems, and an improvement thereof has been demanded.
[0009]
In other words, the rotational speed of the bearing is restricted mainly by the temperature rise caused by frictional heat generated inside, and when the rotational speed reaches a certain limit or more, the continuous operation cannot be performed due to bearing seizure or the like. . The rotational speed at which operation can be performed without causing heat generation such as seizure is called the allowable rotational speed of the bearing, and the allowable value is allowable d_mThe n value is generally used. This d_mThe n value is expressed by the following equation for radial bearings.
[0010]
d_mn ≦ f₁・ F₂・ F_Three・ A
Where d_m: Arithmetic average value of inner and outer diameter of bearing (mm)
n: Rotational speed (rpm)
f₁: Correction factor according to bearing dimensions
f₂: Correction factor depending on the magnitude of load
f_Three: Correction coefficient by composite load
A: Value that determines the allowable rotational speed
[0011]
This allowable rotational speed (allowable d_mThe (n value) varies depending on the bearing standard, the specific structure type, and the like, but is largely dependent on the lubrication method.
[0012]
In particular, in the structure of the support bearing d described above, when the cylindrical roller j is used as the rolling element, the contact between the cylindrical rollers j, j,... And the raceways of the inner and outer rings f, h is a line contact. Compared with a ball bearing that makes point contact, such as the front bearing c, the contact area is large. Therefore, frictional heat is likely to be generated due to rolling of the rolling element j, and lubrication is supplied from the injection hole l of the outer ring h. The area around the agent is also inferior. As a result, the allowable rotational speed of the bearing is relatively low, and there has been a possibility that seizure may occur as a support bearing for the recently-rotated main spindle b, which has been difficult to adopt.
[0013]
In addition, since a metal cage is generally used for this type of cylindrical roller bearing, there is a risk that seizure may occur and seizure may occur. From this point as well, high-speed rotation of the rotating spindle b is possible. It was difficult.
[0014]
Regarding these points, it is conceivable to use an angular ball bearing with excellent lubricity as the support bearing d on the rear side. However, the angular ball bearing bears both a radial load and an axial load. Since the degree of freedom in the axial direction cannot be obtained, it is necessary to devise a structure that gives the degree of freedom in the axial direction outside the bearing, and the structure becomes complicated, leading to an increase in manufacturing costs and product costs. It will cause problems.
[0015]
The present invention has been made in view of such conventional problems, and its object is to use a spherical rolling element to rotate a rotating shaft that rotates at high speed while allowing movement in the axial direction. An object of the present invention is to provide a bearing device having a structure that can be pivotally supported.
[0016]
[Means for Solving the Problems]
  In order to achieve the above object, the bearing device of the present invention has a plurality of rolling elements arranged between the inner and outer races so as to be able to roll, and the shaft is rotatably supported while allowing the rotation shaft to move in the axial direction. The plurality of rolling elements arranged between the inner and outer races are in the form of spherical rolling elements, and are held rotatably by a cage at a predetermined interval in the circumferential direction. Among the tracks of the inner and outer races on which the rolling elements roll, at leastInner ringIs in the form of a straight track with a straight cross sectionThe inner raceway is fastened to the rotary shaft by a nut, the inner peripheral surface of the inner raceway has a tapered surface, and the raceway mounting surface of the rotary shaft is the inner raceway. It is a tapered surface corresponding to the peripheral surface, and the outer diameter of the linear track of the inner race can be finely adjusted by tightening the nut.It is characterized by.
[0017]
As a preferred embodiment, one of the tracks of the inner and outer races is in the form of a linear track having a linear cross section, and the other track is in the form of a track groove having an arc-shaped cross section. Alternatively, the raceway of both the inner and outer races is in the form of a linear race having a linear cross section, and the movement of the spherical rolling element in the axial direction is restricted to either the inner race or the outer race. Regulatory means are provided.
[0018]
The spherical rolling element is formed from a ceramic material, and the cage is formed from an oil-containing phenol resin.
[0019]
The spindle device according to the present invention is characterized in that, among the pair of front and rear bearings that rotatably support the rotating main shaft, the rear support bearing is constituted by the bearing device, and is preferably driven inside the device. This is a spindle device with a built-in motor in which a motor is integrated.
[0020]
In a bearing device according to the present invention, for example, a bearing device used as a support bearing on the rear side of the spindle device with a built-in motor as described above, when the rotary main shaft is rotationally driven by a drive motor, the bearing Due to thermal expansion due to heat generation of the part, the rotational main shaft undergoes a dimensional change in the axial direction, that is, elongation, and the plurality of rolling elements arranged between the inner and outer races of the bearing device are in the form of spherical rolling elements. In addition, at least one of the tracks of the inner and outer races is in the form of a linear race having a linear cross section, so that the inner and outer races move relatively in the axial direction following the extension of the rotating main shaft. As a result, the elongation of the rotating main shaft is effectively absorbed inside the bearing device.
[0021]
In this case, since the rolling elements arranged between the inner and outer races are spherical rolling elements, the contact between the spherical rolling elements and the raceway of the inner and outer races is a point contact, and frictional heat is generated by the rolling of the rolling elements. However, the amount of lubricant injected by the oil-air lubrication method is good as compared with the cylindrical roller, and the allowable rotational speed of the bearing device can be improved.
[0022]
In addition, if ceramics with low specific gravity and high heat resistance are used as the constituent material of rolling elements, seizure during high-speed rotation can be effectively prevented, or the specific gravity is low and oil-impregnating as a constituent material of the cage. By using a phenolic resin having high heat resistance, it is superior in lubricity and more suitable for high-speed rotation than when a metal cage is used.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0024]
Embodiment 1
A spindle apparatus according to the present invention is shown in FIG. 1, and specifically, this spindle apparatus is installed in a headstock of a machine tool such as a grinding machine, and a rotary tool having a rotary tool attached to a tip portion thereof. This is a spindle device with a built-in motor that includes a main shaft 1 and a drive motor 2 integrally incorporated in the device as main parts.
[0025]
The rotary main shaft 1 is rotatably accommodated and held in a housing 5 by a pair of front and rear bearings 3 and 4 that support the front and rear positions thereof, and a tool attachment for removably attaching a rotary tool (not shown) to the tip portion thereof. While having the part 1a, the center part is drive-coupled to the drive motor 2.
[0026]
The front bearing 3 is located close to the rotary tool and rotatably supports the rotary main shaft 1. The front bearing 3 is composed of two angular ball bearings 31 and 32, and both a radial load and an axial load acting on the rotary main shaft 1. To bear. The specific structures of the angular ball bearings 31 and 32 are well known in the art and will not be described in detail.
[0027]
The rear bearing 4 is a so-called support bearing that is located far from the rotary tool and rotatably supports the rotary main shaft 1 while allowing movement in the axial direction thereof, and has a structure as shown in FIG. It becomes.
[0028]
The support bearing 4 is in the form of a ball bearing using a spherical rolling element, that is, a rolling ball, as the rolling elements 10, 10,..., And an inner ring that is fixedly attached to the rotating main shaft 1 on the rotating side. (Inner race ring) 11 and outer ring (outer race ring) 12 attached and fixed to the housing 5 on the fixed side are relatively movable in the axial direction.
[0029]
  Specifically, the track 11a formed on the outer peripheral surface of the inner ring 11 is in the form of a linear track having a linear cross section as shown, and the track 12a formed on the inner peripheral surface of the outer ring 12 MovementballCurvature corresponding to 10 curvature, that is, rollingballIt is in the form of a deep groove-like raceway groove having an arc-shaped cross section with a curvature slightly larger than 10 curvatures. These inner and outer rings 11 and 12 are made of bearing steel.
[0030]
The rolling balls 10 interposed between the inner and outer rings 11 and 12 so as to be able to roll are rotatably held in the respective ball pockets 13a of the cage 13, and are arranged at predetermined intervals in the circumferential direction. The rolling ball 10 is formed of a ceramic material having a small specific gravity and high heat resistance, and the cage 13 is formed of an oil-containing phenol resin having a small specific gravity, oil-impregnating property, and high heat resistance.
[0031]
Further, the ball pocket 13a of the cage 13 has a small tapered cross section tapered downward as shown in the drawing, and its lower end opening is slightly smaller than the outer diameter of the rolling ball 10. Yes. Then, the rolling ball 10 is fitted into the ball pocket 13a from the inner diameter side by one-touch by elastic deformation of the lower end opening, and the once inserted rolling ball 10 is prevented from dropping out to the inner diameter side. It is configured. Thereby, the rolling balls 10, 10,... And the outer ring 12 have a unit structure that is integrally assembled via the cage 13.
[0032]
.., Outer ring 12 and retainer 13 having the unit structure as described above are inserted into the mounting recess 5a of the housing 5 and pressed and fixed by the outer ring presser 14 to the housing. 5 is attached.
[0033]
On the other hand, the inner ring 11 is fitted and inserted into the rear end 1 b of the rotary spindle 1 and is fastened and fixed by an inner ring nut 15. Specifically, the inner peripheral surface 11b of the inner ring 11 is formed in a taper surface tapered toward the rear, and the outer peripheral surface (the bearing ring mounting surface) of the rear end portion 1b of the rotary main shaft 1 is the inner ring 11 inside the inner ring 11. The taper surface corresponds to the peripheral surface 11b. As a result, the inner ring 11 is tightened to finely adjust the expansion of the inner ring 11 and the outer diameter of the linear track 11a, and the clearance between the rolling balls 10, 10,... Adjustment is possible (fine adjustment on the order of μm is possible) and rigidity is increased.
[0034]
In the support bearing 4 having such a structure, the track of the inner ring 11 is a straight track 11a, so that the inner and outer rings 11, 12 can relatively move in the axial direction.
[0035]
As a result, even if there is a cumulative error between components due to the assembly of the spindle device, or even if the rotational main shaft 1 expands in the axial direction due to heat generated during high-speed rotation, a dimensional displacement occurs. The four inner rings 11 can move in the axial direction with respect to the rolling balls 10, 10,..., And further the outer ring 12, so that an axial assembly dimension error and a dimensional displacement with respect to the rotating spindle 1 can be effectively absorbed. It is configured.
[0036]
The drive motor 2 is disposed between the pair of front and rear bearings 3, 4. Specifically, the stator 15 is fixed to the inner peripheral cylindrical portion of the housing 5, and the rotor 16 corresponds to this. Is fixed at a predetermined position of the rotary main shaft 1, whereby the inner diameter surface of the stator 15 and the inner diameter surface of the rotor 16 are arranged to face each other with a predetermined gap 17.
[0037]
Further, the housing 5 is provided with a lubricating oil supply passage 20 for effectively lubricating and cooling the inside of the front and rear bearings 3 and 4. The supply passage 20 is provided so as to penetrate through the housing 5, and the tip 20 a of the injection passage faces the inside of the bearings 3 and 4 (the portion between the cage 13 and the inner ring 11 in the illustrated example). The base end 20b communicates with a lubricating oil supply source (not shown). As a result, the lubricating oil supplied from the lubricating oil supply source is injected and supplied into the front and rear bearings 3 and 4 through the lubricating oil supply passage 20 to ensure smooth rotation of the bearings 3 and 4. In addition, heat generation is prevented.
[0038]
Thus, in the spindle apparatus configured as described above, the rotary spindle 1 is driven to rotate at a high speed by the drive motor 2, and the rotary tool (not shown) attached to the tool attachment part 1a at the tip part rotates at a high speed. Then, the workpiece is processed.
[0039]
In this case, the drive motor 2 and the front and rear bearings 3 and 4 generate heat as the rotation main shaft 1 is rotated at a high speed by the drive motor 2, whereby the rotation main shaft 1 is thermally expanded and changes in dimensions in the axial direction. That is, although elongation occurs, this elongation is effectively absorbed and removed by the rear support bearing 4.
[0040]
That is, as described above, since the race of the inner ring 11 on which the rolling balls 10, 10,... Roll is the linear race 11a, the support bearing 4 has the inner and outer rings even if the rotation main shaft 1 is elongated. 11 and 12 can move relatively in the axial direction following the elongation, and as a result, the elongation of the rotating main shaft 1 is effectively absorbed inside the support bearing 4. On the other hand, when the rotation main shaft 1 stops rotating, it gradually cools, and the dimensional change in the axial direction becomes the dimensional change in the shrinking direction contrary to the above, but this shrinkage is also effective by the reverse operation of the support bearing 4. Will be absorbed and removed.
[0041]
Further, since the rolling elements 10, 10,... Of the support bearing 4 are the same rolling balls as the front bearing 3, the rolling balls 10, 10,... And the raceways 11a, 12a of the inner and outer rings 11, 12 are connected. The contact is a point contact, the frictional heat generated by the rolling of the rolling balls 10, 10,... Is relatively small, and the lubricant injected into the bearing through the lubricating oil supply passage 20 by the oil-air lubrication method enters the bearing. The rotation is also good, and the allowable rotational speed of the support bearing 4 (the above-mentioned allowable d_m(represented by the n value).
[0042]
Further, when the centrifugal force acts on the rolling balls 10, 10,... By the high-speed rotation of the rotation main shaft 1, if the raceway 12a of the outer ring 12 is in the form of a raceway groove, it is effective in terms of wear resistance. .
[0043]
In addition, the rolling ball 10 is made of ceramic with high heat resistance, and in addition to being hard to seize even at high speed rotation, the cage 13 is also made of a phenolic resin that is oil-impregnated and excellent in heat resistance. From this point, the structure is suitable for high-speed rotation.
[0044]
Embodiment 2
This embodiment is shown in FIG. 3, in which the structure of the rear support bearing 4 is modified. Specifically, the inner and outer rings 11 and 12 have a structure opposite to that of the first embodiment.
[0045]
That is, the raceway 11a of the inner ring 11 is in the form of a raceway groove having an arcuate cross section corresponding to the rolling balls 10, 10,..., And the raceway 12a of the outer ring 12 is in the form of a linear raceway having a linear cross section. ing.
[0046]
Further, the ball pocket 13a of the cage 13 is formed into a spherical surface corresponding to the outer diameter of the rolling ball 10 as shown in the drawing, and the upper end opening thereof is smaller than the outer diameter of the rolling ball 10, The rolling ball 10 is configured so as not to drop upward. Thereby, the rolling balls 10, 10,... And the inner ring 11 have a unit structure that is integrally assembled via the cage 13.
[0047]
Further, the inner peripheral surface 11b of the inner ring 11 is formed as a cylindrical surface having the same diameter, and the outer peripheral surface (the bearing ring mounting surface) of the rear end portion 1b of the rotary main shaft 1 also corresponds to the inner peripheral surface 11b of the inner ring 11. It is a cylindrical surface.
[0048]
Therefore, even if an axial assembly dimensional error or dimensional displacement occurs with respect to the rotating main shaft 1, the inner ring 11 and the rolling balls 10, 10,... Of the support bearing 4 move in the axial direction with respect to the outer ring 12. These assembly dimensional errors and dimensional displacements can be effectively absorbed.
Other configurations and operations are the same as those of the first embodiment.
[0049]
Embodiment 3
This embodiment is shown in FIG. 4, and the structure of the rear support bearing 4 is modified. Specifically, a double row in which rolling balls 10, 10,... It is in the form of a ball bearing.
[0050]
That is, two rows of raceway grooves 12a, 12a are arranged in parallel on the inner circumferential surface of the outer ring 12, and the rolling balls 10, 10,... Roll along the raceway grooves 12a, 12a. It is supposed to be a structure. The rolling balls 10, 10,... In each row are rotatably held in the ball pockets 13a, 13a,.
[0051]
Further, the specific structure of the ball pocket 13a of the cage 13 is the same as that of the second embodiment.
[0052]
The number of arrangement of the raceway grooves 12a is not limited to two as shown in the figure, and is appropriately set in relation to the shape and size of other components in consideration of the load to be borne.
[0053]
The tip 20a of the lubricating oil supply passage 20 is communicated with the injection port 21 facing the inside of the bearing from between the two rows of raceway grooves 12a, 12a in the outer ring 12.
Other configurations and operations are the same as those of the first embodiment.
[0054]
Embodiment 4
This embodiment is shown in FIG. 5, and the structure of the rear support bearing 4 is modified. Specifically, the outer ring 12 is divided.
[0055]
That is, the outer ring 12 has a two-part structure composed of a pair of outer ring members 22 and 23, and raceway grooves 22 a and 23 a are provided at opposite positions of the outer ring members 22 and 23. The both raceway grooves 22a and 23a form a deep groove-like raceway groove having a substantially arc-shaped cross section corresponding to the rolling ball 10, and the rolling ball 10 contacts the raceway grooves 22a and 23a in a two-point contact state. Rollable.
[0056]
By adopting such a structure, the clearance between the rolling balls 10, 10,... And the track 11a of the inner ring 11 is adjusted by appropriately adjusting the relative axial positions of the outer ring members 22, 23. It is possible to adjust.
[0057]
Correspondingly, as in the second embodiment, the inner peripheral surface 11b of the inner ring 11 is formed in a cylindrical surface having the same diameter, and the outer peripheral surface (the bearing ring mounting surface) of the rear end portion 1b of the rotary main shaft 1 is also described above. A cylindrical surface corresponding to the inner peripheral surface 11 b of the inner ring 11 is used.
[0058]
The tip 20a of the lubricating oil supply passage 20 is communicated with a gap 24 between the outer ring members 22 and 23 so that the lubricating oil is injected and supplied from the gap 24 into the bearing.
Other configurations and operations are the same as those of the first embodiment.
[0059]
Embodiment 5
This embodiment is shown in FIG. 6, and the structure of the rear support bearing 4 is modified. Specifically, the tracks 11a, 12a of both the inner and outer rings 11, 12 are linear tracks.
[0060]
That is, both the tracks 11a and 12a of the inner and outer rings 11 and 12 are in the form of a linear track having a linear cross section, and both the tracks 11a and 12a allow the axial movement of the rolling balls 10, 10,. It is structured.
[0061]
Correspondingly, restricting lids (regulating means) 25 and 25 for defining the maximum axial movement range of the retainer 13 are provided on both end surfaces of the outer ring 12 in the axial direction. The movement of 10, 10,... In the axial direction is restricted, so that the rolling balls 10, 10,.
The restriction lids 25 and 25 may be provided on the inner ring 11 side.
[0062]
Further, the tip 20a of the lubricating oil supply passage 20 is connected to an injection port 26 provided at the axial end of the outer ring 12, and the lubricating oil is supplied from the injection port 26 into the bearing. Has been.
[0063]
Thus, even if an axial assembly dimensional error or dimensional displacement with respect to the rotating main shaft 1 occurs, the inner ring 11 of the support bearing 4 moves in the axial direction with respect to the rolling balls 10, 10,. These assembly dimensional errors and dimensional displacements can be effectively absorbed.
Other configurations and operations are the same as those of the first embodiment.
[0064]
In addition, Embodiment 1-5 mentioned above shows the suitable embodiment of this invention to the last, Comprising: This invention is not limited to these, A design can be changed suitably within the range.
[0065]
For example, in the illustrated embodiment, the rolling ball 10 and the cage 13 are made of a ceramic material and an oil-containing phenol resin material, respectively, so that the weight of the bearing device and the wear resistance can be improved. However, the present invention is not limited to this, and other materials may be used.
[0066]
Further, the present invention is applicable not only to a spindle device with a built-in motor that is mounted on a head stock of a machine tool such as a grinding machine as shown in the illustrated embodiment, but also to a bearing of another spindle device or a rotating device.
[0067]
【The invention's effect】
  As described above in detail, according to the bearing device of the present invention, the plurality of rolling elements arranged between the inner and outer races are in the form of a spherical rolling element, and at a predetermined interval in the circumferential direction by the cage. Of the races of the inner and outer races, which are held rotatably and the spherical rolling elements roll, at least the inner race is in the form of a linear race having a linear cross section.The inner raceway is fastened to the rotary shaft by a nut, the inner peripheral surface of the inner raceway has a tapered surface, and the raceway mounting surface of the rotary shaft is the inner raceway. It is a tapered surface corresponding to the peripheral surface, and the outer diameter of the linear track of the inner race can be finely adjusted by tightening the nut.Therefore, various excellent effects as listed below are exhibited, and a bearing device having a structure capable of rotatably supporting a rotating shaft that rotates at high speed while allowing movement in the axial direction thereof is allowed. Can be provided.
[0068]
(1) For example, in a bearing device that is used as a support bearing on the rear side of a rotation spindle of a spindle device with a built-in motor, when the rotation spindle is driven to rotate by a drive motor, thermal expansion due to heat generation of the bearing portion, etc. As a result, the rotation main shaft causes a dimensional change in the axial direction, that is, elongation, but the inner and outer races follow the elongation of the rotation main shaft and move relatively in the axial direction. Will be absorbed effectively.
[0069]
(2) Since the rolling elements arranged between the inner and outer races are spherical rolling elements, the contact between the spherical rolling elements and the raceway of the inner and outer races is a point contact, and frictional heat due to rolling of the rolling elements Is less than that of cylindrical rollers, and the lubricant sprayed by the oil-air lubrication method, etc. is good, the temperature rise is reduced, and the allowable rotational speed of the bearing device can be improved. It is possible to effectively cope with the recent increase in the speed of the spindle device (from the result of the characteristic test of the allowable rotational speed, the allowable d_mAlthough it was found that the n value was about 20,000, the bearing device of the present invention is capable of high-speed rotation of 1,500,000 or more).
[0070]
(3)In addition, the inner raceway is fastened to the rotary shaft with a nut, the inner peripheral surface of the inner raceway is formed into a tapered surface, and the raceway mounting surface of the rotary shaft is the inner raceway of the inner raceway. Since the outer diameter of the linear raceway of the inner raceway can be finely adjusted by tightening the nut, the clearance between the rolling element and the raceway of the inner raceway can be finely adjusted. Adjustment is possible (fine adjustment on the order of μm is possible) and rigidity is increased.
(Four) Furthermore, if a ceramic having a small specific gravity and excellent heat resistance is used as the constituent material of the rolling elements, the heat resistance of the bearing can be improved and seizure during high-speed rotation can be effectively prevented.
[0071]
(Five) Similarly, as a constituent material of the cage, by using a high phenol resin having a small specific gravity, oil-impregnating properties and excellent heat resistance, it is superior in lubricity than when a metal cage is used, Troubles due to poor lubrication and wear of sliding parts can be effectively prevented, and the allowable number of rotations of the bearing can be greatly improved. As a result, it is suitable for high-speed spindle devices, and the life of the spindle device is greatly increased. It contributes to the improvement.
[0072]
(6) The structure is simple and the manufacturing cost and product cost can be reduced. In particular, it is possible to use commercially available components other than the bearing ring having a straight track, and by adopting such a configuration, a significant cost reduction is realized.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing a spindle apparatus according to a first embodiment of the present invention.
2 is an enlarged side cross-sectional view of a rear support bearing in the spindle device, FIG. 2 (a) shows a support bearing alone, and FIG. 2 (b) shows a state where it is incorporated in a spindle device. Show.
FIG. 3 is a side cross-sectional view corresponding to FIG. 2, showing a rear support bearing in a spindle device according to a second embodiment of the present invention.
4 is a side cross-sectional view corresponding to FIG. 2, showing a rear support bearing in a spindle device according to a third embodiment of the present invention.
FIG. 5 is a side cross-sectional view corresponding to FIG. 2, illustrating a rear support bearing in a spindle device according to a fourth embodiment of the present invention.
6 is a side cross-sectional view corresponding to FIG. 2, showing a rear support bearing in a spindle device according to a fifth embodiment of the present invention.
7 shows a conventional spindle device, FIG. 7 (a) is a side sectional view corresponding to FIG. 1, and FIG. 7 (b) is a side sectional view corresponding to FIG. 2 showing an enlarged view of a rear support bearing. It is.
[Explanation of symbols]
1 Spindle
2 Drive motor
3 Front bearing
4 Support bearing (rear bearing)
5 Housing
10 Rolling balls (rolling elements)
11 Inner ring (inner race)
12 Outer ring (outer raceway)
13 Cage
22 Outer ring member
25         Regulatory lid (regulatory means)

Claims (8)

A bearing device in which a plurality of rolling elements are arranged so as to be able to roll between inner and outer races, and rotatably supports the rotating shaft while allowing movement in the axial direction thereof,
The plurality of rolling elements disposed between the inner and outer races are in the form of spherical rolling elements, and are held rotatably by the cage at a predetermined interval in the circumferential direction.
Of the races of the inner and outer races on which these spherical rolling elements roll, at least the inner race is in the form of a linear race having a linear cross section ,
The inner race ring is fastened to the rotating shaft by a nut;
The inner circumferential surface of the inner race is in the form of a tapered surface, and the bearing ring mounting surface of the rotating shaft is a tapered surface corresponding to the inner circumferential surface of the inner race,
The bearing device , wherein the outer diameter of the linear raceway of the inner raceway can be finely adjusted by tightening the nut . 2. The bearing device according to claim 1 , wherein the bearing ring on the side having a raceway groove of the inner and outer raceways is divided into two parts in the axial direction.  The track of the inner and outer races is in the form of a linear race having a linear cross section, and the regulation means for regulating the movement of the spherical rolling element in the axial direction on either the inner race or the outer race The bearing device according to claim 1, wherein the bearing device is provided. The bearing device according to any one of claims 1 to 3 , wherein the raceway grooves are arranged in a plurality of rows in parallel. The spherical rolling element bearing device according it to any one of claims 1 4, characterized in being formed from a ceramic material. The bearing device according to any one of claims 1 to 5 , wherein the cage is formed of an oil-containing phenol resin. 7. A spindle device that is mounted on a machine tool and includes a rotation main shaft, wherein a support bearing on the rear side of a pair of front and rear bearings that rotatably support the rotation main shaft is any one of claims 1 to 6. A spindle device comprising the bearing device according to claim 1. The spindle apparatus according to claim 7 , wherein a built-in motor is integrally incorporated in the apparatus.

Images