JP5517680B2 - Rolling bearings and machine tool spindle devices - Google Patents

Description

  The present invention relates to a rolling bearing used for supporting a spindle of a machine tool and a spindle device of a machine tool.

  In a spindle device having a high-speed main shaft in a machine tool such as a machining center, for example, a combination bearing in which angular ball bearings are arranged back to back is used as a bearing for supporting the main shaft. In such a use example, when the combination bearing is assembled to the main shaft, it is necessary to confirm the direction of the contact angle of each bearing, but it cannot be easily confirmed only by looking at the appearance.

  Therefore, in such a use example, as a measure for visually recognizing the contact angle direction of the bearing from the outside during assembly, a mark 32 indicating the direction of the contact angle α on the outer peripheral surface of the bearing outer ring 31 as shown in FIG. Have been proposed, and those in which the colors of the seals 33 provided at both ends of the bearing are different from each other (for example, Patent Document 1).

JP 2006-125433 A

However, in the case of a visual measure that displays a mark indicating the direction of the contact angle on the outer peripheral surface of the outer ring, a mark is added to the outer ring of the steel bearing, so a separate process for adding the mark is required in the machining process. There is a problem that it leads to an increase in man-hours and costs.
Also, in the case of a visual measure to make the seal colors at both ends of the bearing different from each other, when assembling the bearing to the main shaft, the direction of the contact angle can be visually confirmed from the color of the seal, but I want to confirm the directionality of the assembled bearing later In particular, in the case of three or more rows of combined bearings, the color of the seal cannot be visually recognized from the outside except for the bearings located at both ends.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a rolling bearing and a spindle device for a machine tool in which the directionality of the bearing can be easily visually recognized from the outside regardless of before and after the assembling work, and the man-hour and cost are not increased. .

The rolling bearing according to the present invention includes an inner ring, an outer ring, and a plurality of rolling elements interposed between the raceways of the inner and outer rings, and the internal structure or function has directionality on the front side and the back side, and two or more are provided. in the rolling bearing to be used as a combined bearing arranged in the axial direction, characterized in that different for each other physicians for the surface roughness of the finish-shaped state of the chamfered portion of the front side and the rear side of the outer peripheral surface of the outer ring .
According to this configuration, the front and back chamfered finishes on the outer peripheral surface of the outer ring are different from each other, so when used as a combined bearing, the directionality of the bearing can be adjusted regardless of before and after the assembly work. It can be easily visually recognized from the outside. Moreover, since the difference in the finishing form of the chamfered portion can be applied as a part of the finishing process of the outer peripheral surface of the outer ring, it does not lead to an increase in man-hours and costs.

As a reference proposal example , the shapes of the finished forms of the chamfered portions on the front side and the back side of the outer peripheral surface of the outer ring may be different from each other. The term “shape” in this specification means a shape in a broad sense that includes the concept of dimensions in addition to a shape in a narrow sense that does not include the concept of dimensions. Suppose there is.
In the case of this configuration, the directionality of the bearing can be easily visually recognized from the outside due to the difference in the shape of the chamfered portions on the front side and the back side.

In this case, the difference in shape between the chamfered portions on the front side and the back side may be that the at least axial dimensions of the chamfered portions are different from each other. When the axial dimensions are different from each other, visual recognition is much easier.
If the shape of the finished form is made different from each other only by changing the axial dimension of the double-sided chamfered part, the radial dimension for securing the contact surface pressure on both end faces of the outer ring will not be insufficient, and the radial direction will be sufficient. Dimensions can be secured.

In addition, the chamfered portion has a shape in which the cross section forms an arcuate curve, and the difference in shape between the chamfered portions on the front side and the back side is determined by the corner R dimension and the axis that are the radius of curvature of the arcuate curve. Both of the directional dimensions may be different from each other.
In the case of this configuration, not only the axial dimension of the double-sided chamfered part but also the corner R dimension are different from each other, so that the difference in the finished shape of the double-sided chamfered part is conspicuous, and the directionality of the bearing from the outside can be visually confirmed. Is even easier.

Furthermore, the difference in the shape of the chamfered portions on the front side and the back side may be that both the axial dimension and the radial dimension of the double-sided chamfered part are different from each other.
In this configuration, not only the axial dimension of the double-sided chamfered part but also the radial dimension are different from each other, so the difference in the finished shape of the double-sided chamfered part becomes even more conspicuous, and the directionality of the bearing from the outside Visual recognition becomes easier.

As a reference proposal example , when the axial dimension of the chamfered part on the front side is XF and the axial dimension of the chamfered part on the back side is XB among the chamfered parts on the front side and the back side in the case of each configuration described above. These two axial dimensions XF and XB are
XF x 2 ≤ XB ≤ XF x 5
It is desirable to set so as to satisfy this relationship.
The reason why XF × 2 ≦ XB is that it is difficult to visually distinguish the double-sided chamfered portion at a glance unless there is a difference of about 2 times between the axial dimensions of the double-sided chamfered portion. The reason why XB ≦ XF × 5 is that when the axial dimension XB of the chamfered portion on the back side is more than five times the axial dimension XF of the chamfered portion on the front side, the fitting portion of the outer peripheral surface of the outer ring becomes small. This is because there are concerns about problems such as creep.

The surface roughness of the finished form of the chamfered portion of the front side back side of the outer peripheral surface of the upper Kigairin different from each other.
In this way, when the surface roughness in the finished form of the chamfered portion on the front side and the backside on the outer peripheral surface of the outer ring is made different, the color tone of the chamfered portions on the front side and the backside looks different. As a result, when used as a combination bearing, the directionality of the bearing can be easily visually recognized from the outside regardless of before and after the assembly work due to the difference in color tone of the double-sided chamfered portion. Further, the difference in the surface roughness of the double-sided portion can be applied as part of the finishing process of the outer peripheral surface of the outer ring, so that it does not lead to an increase in man-hours and cost.

In this case, when the surface roughness of the chamfered portion on the front side among the chamfered portions on the front side and the rear side is SRF and the surface roughness of the chamfered portion on the back side is SRB, both the surface roughness SRF, SRB
SRF ≦ Ra0.8
And Ra1.6 ≦ SRB ≦ Ra25
Or SRB ≦ Ra0.8
And Ra1.6 ≦ SRF ≦ Ra25
It may be set so as to satisfy the relationship.

  In addition, the difference in surface roughness between the chamfered portion on the front side and the backside is that one of the chamfered portions is heat-treated in a cutting finish, and the outer chamfered portion of the other chamfered portion is heat treated after heat treatment. It may be different from each other by performing the same grinding finish as the part. This configuration also does not lead to an increase in man-hours or costs.

In the case of each of the above configurations of the present invention, there is a step which enters and exits from each other in the axial direction between the end face of the inner ring and the end face of the outer ring, and the step between the end faces between the inner and outer rings on the front side and the inner and outer rings on the back side. The step on the end face may be set to be the same.
In this way, even when there are steps on the end faces of the inner ring and the outer ring, by setting the step on the front side and the step on the back side to be the same, the arrangement order of the rolling bearings can be clearly understood when used as a combined bearing. Instead, only by distinguishing the directionality of the bearing, it is possible to easily assemble the combination bearing that is pre-set by fitting with the shaft and fitting with the housing.

  The combination bearing of the present invention is a combination of a plurality of rolling bearings of any one of the above configurations of the present invention arranged in contact with each other in the axial direction.

The spindle device for a machine tool according to the present invention is characterized in that a plurality of the rolling bearings according to the present invention are installed as a combination bearing for supporting the main shaft.
Thus, in the spindle apparatus using the rolling bearing of the present invention as a combined bearing for supporting the main shaft, the directionality of the bearing can be easily visually recognized from the outside regardless of before and after the assembly work of the bearing.

A rolling bearing according to the present invention includes an inner ring, an outer ring, and a plurality of rolling elements interposed between the raceways of the inner and outer rings, and the rolling bearing used as a combined bearing in which two or more are arranged in the axial direction. since having different to each other physicians for the surface roughness of the finish-shaped state of the chamfered portion of the front and rear side of the outer peripheral surface, it can be easily viewed from outside the direction of the bearing either before or after the assembling work, steps It does not lead to increase or cost increase.
The spindle device for a machine tool according to the present invention uses the rolling bearing according to the above invention as a combined bearing that supports the main shaft, so that the directionality of the bearing can be easily visually recognized from the outside regardless of whether the bearing is assembled or not. Can do.

It is sectional drawing of the rolling bearing concerning a reference proposal example . It is a sectional view showing an example of a combined bearing using the rolling rising bearing of FIG. It is a cross-sectional view showing another example of a combined bearing using the rolling rising bearing of FIG. It is sectional drawing of the rolling bearing concerning the other reference proposal example . It is a cross-sectional view of a rolling bearing to other references proposed examples et of. It is a cross-sectional view of a rolling bearing according to the implementation embodiments of the present invention. It is sectional drawing of the rolling bearing concerning other embodiment of this invention. It is sectional drawing of the spindle apparatus using the combination bearing of FIG. 2 and FIG. It is sectional drawing which fractures | ruptures and shows a part of prior art example.

A reference proposal example will be described with reference to FIGS. FIG. 1 shows a half sectional view of the rolling bearing of this reference proposal example . The rolling bearing 1 is a bearing that has a front side and a back side direction in internal structure or function, and is used as a combined bearing by arranging two or more in the axial direction. Here, an angular contact ball having a contact angle α is used. It consists of a bearing. The rolling bearing 1 includes an inner ring 2, an outer ring 3, a plurality of rolling elements 4 interposed between the raceway surfaces 2 a and 3 a of the inner and outer rings 2 and 3, and a holding for holding these rolling elements 4 equally distributed in the circumferential direction. A vessel 5 is provided. In the rolling bearing 1 in the figure, the right side of the figure is the front side and the left side is the back side. The rolling element 4 consists of a ball.

In this rolling bearing 1, chamfered portions 3 bB and 3 bF having a cross-sectionally curved curve are provided at the front and back end portions of the outer peripheral surface of the outer ring 3. The chamfered portions 3bB and 3bF on both sides have different finishing forms. Here, the shapes of the finishing forms are different from each other. Specifically, the axial dimension XB of the chamfered portion 3bB on the back side (left side in the drawing) and the axial dimension XF of the chamfered portion 3bF on the front side (right side) are different from each other. That is, in FIG. 1, between these axial dimensions XB and XF,
XB> XF (1)
The size relationship is set.

  FIG. 2 shows an example of a combined bearing 10 that uses two rolling bearings 1 of FIG. 1 and has these rolling bearings 1E and 1F in a DB array that are back to back. FIG. 3 shows an example of another combination bearing 11 in which the four rolling bearings 1 of FIG. 1 are used and these rolling bearings 1A, 1B, 1C, 1D are arranged in the axial direction. In this combination bearing 11, two rows and one set of rolling bearings 1 </ b> A and 1 </ b> B and another two rows and one set of rolling bearings 1 </ b> C and 1 </ b> D are arranged in a DTBT arrangement that are back to back.

  In this way, in this rolling bearing 1, the front and back side chamfered portions 3bB and 3bF on the outer peripheral surface of the outer ring 3 are different from each other in the finished form. When used as 11, the directionality of the bearing (specifically, the direction of the contact angle) can be easily visually recognized from the outside regardless of before and after the assembling work. Further, since the difference in the finishing form of the chamfered portions 3bB and 3bF can be applied as a part of the finishing process of the outer peripheral surface of the outer ring 3, it does not lead to increase in man-hours and cost.

Further, in this reference proposal example , only the axial dimensions XB and XF of the front and rear chamfered portions 3bB and 3bF on the outer peripheral surface of the outer ring 3 are made different so that the shapes of the finished forms of the double-sided chamfered portions 3bB and 3bF are mutually different. Since they are different, the direction of the contact angle can be easily visually recognized from the outside due to the difference in shape. Further, the radial dimension for securing the contact surface pressure at both end faces of the outer ring 3 is not insufficient, and the radial dimension can be sufficiently secured.

FIG. 4 shows another reference proposal example . In the rolling bearing 1 of this reference proposed example, in Reference proposed example of FIG. 1, the outer peripheral surface of the front side and back side of the chamfer 3bB of the outer ring 3, the axial dimension XB of 3bF, well XF, chamfer 3bB, The corner R dimensions RB and RF, which are the radii of curvature, in the arc-shaped curve of the cross section of 3bF are also made different from each other, thereby making the shapes of the finished forms of the double-sided chamfers 3bB and 3bF different from each other. That is, in FIG. 4, the magnitude relationship (XB> XF) of the above equation (1) is set between the axial dimensions XB and XF, and the corner R dimension RB of the chamfered portion 3bB on the back side (left side) Between the front side (right side) 3bF corner radius R dimension,
RB> RF ......... (2)
The size relationship is set. Other configurations are the same as those of the reference proposal example of FIG.

Also in the case of this reference proposal example , the shape of the finished form of the chamfered portions 3bB and 3bF on the front side and the back side on the outer peripheral surface of the outer ring 3 is different from each other. When used as the bearings 10 and 11, the direction of the contact angle can be easily visually recognized from the outside regardless of before and after the assembling work. It is also the same that the man-hours and costs are not increased by making the finished shapes of the double-sided chamfers 3bB and 3bF different. In the case of this embodiment, not only the axial dimensions XB and XF of the double-sided chamfers 3bB and 3bF but also the corner R dimensions RB and RF are different from each other, so the difference in the finished shape of the double-sided chamfers 3bB and 3bF is different. It will stand out that much, and it will be easier to visually recognize the direction of the contact angle from the outside.

Figure 5 Hasa et al shows the other references proposed example. In the rolling bearing 1 of this reference proposal example , in the embodiment of FIG. 1, the axial dimensions XB and XF and the radial dimensions YB and YF of the chamfered portions 3bB and 3bF on the front side and the back side of the outer peripheral surface of the outer ring 3 are set to each other. By making them different, the shapes of the finished forms of the double-sided chamfers 3bB and 3bF are made different from each other. That is, in FIG. 5, the magnitude relationship (XB> XF) of the above equation (1) is set between the axial dimensions XB and XF, and the radial dimension YB of the chamfered portion 3bB on the back side (left side) Also between the front side (right side) 3bF radial dimension YF,
YB> YF (3)
The size relationship is set. Other configurations are the same as those of the reference proposal example of FIG.

  Also in the case of this embodiment, since the shapes of the finished forms of the chamfered portions 3bB and 3bF on the outer peripheral surface of the outer ring 3 are different from each other, the combination bearing as shown in FIGS. When used as 10, 11, the direction of the contact angle can be easily visually recognized from the outside regardless of before and after the assembling work. It is also the same that the man-hours and costs are not increased by making the finished shapes of the double-sided chamfers 3bB and 3bF different. In the case of this embodiment, not only the axial dimensions XB and XF of the double-sided chamfers 3bB and 3bF but also the radial dimensions YB and YF are different from each other, so the difference in the finished shape of the double-sided chamfers 3bB and 3bF is different. It will stand out even more, making it easier to visually recognize the direction of the contact angle from the outside.

In each of the above reference proposal examples , the size relationship between the axial dimensions XB and XF of the chamfered portions 3bB and 3bF on the front side and the back side of the outer peripheral surface of the outer ring 3 is as follows.
XF x2≤XB≤XF x5 (4)
It is desirable to set so as to satisfy this relationship. The reason why XF × 2 ≦ XB is that the double-sided portions 3bB and 3bF are visually distinguished at a glance unless there is a difference of about 2 times between the axial dimensions XB and XF of the double-sided portions 3bB and 3bF. Because it is difficult. The reason why XB ≦ XF × 5 is that when the axial dimension XB of the chamfered portion 3bB on the back side is more than five times the axial dimension XF of the chamfered portion 3bF on the front side, the outer circumferential surface of the outer ring 3 is fitted. This is because the portion becomes smaller and there are concerns about problems such as creep.

Figure 6 shows an implementation form of the present invention. In the rolling bearing 1 of this embodiment, in the embodiment of FIG. 1, the surface roughness in the finished form of the chamfered portions 3bB and 3bF on the front side and the back side of the outer peripheral surface of the outer ring 3 is different. Specifically, when the surface roughness of the chamfered portion 3bF on the front side (right side) is SRF and the surface roughness of the chamfered portion 3bB on the back side (left side) is SRB, both surface roughnesses SRF, SRB are:
SRF ≦ Ra0.8 (5)
And Ra1.6 ≦ SRB ≦ Ra25 (6)
Or SRB ≦ Ra0.8 (7)
And Ra1.6 ≦ SRF ≦ Ra25 (8)
It is set to satisfy the relationship. In this case, the size and shape of the double-sided portions 3bB and 3bF may be the same.

  In order to obtain such a difference in surface roughness, for example, when the relational expressions (5) and (6) are satisfied, here, the chamfered portion 3bB on the back side is heat-treated for cutting finish (black skin state). In the chamfered portion 3bF on the front side, the surface roughness SRF, SRB of the double-sided chamfered portions 3bB, 3bF is obtained by performing the same grinding finish as the outer peripheral portion of the outer ring after heat treatment (the finished state having the same metallic luster as the outer peripheral portion of the outer ring). Are different from each other. When the relational expressions (7) and (8) are satisfied, the reverse process is performed.

  As described above, in the rolling bearing 1 of this embodiment, the surface roughness in the finished form of the chamfered portions 3bB and 3bF on the outer peripheral surface of the outer ring 3 is different from each other. The back side chamfers 3bB and 3bF appear to have different colors. As a result, when used as a combination bearing 10 or 11 as shown in FIG. 2 or FIG. It can be visually recognized. Further, since the difference in surface roughness between the double-sided chamfered portions 3bB and 3bF can be applied as part of the finishing process on the outer peripheral surface of the outer ring 3, it does not lead to an increase in man-hours or cost. In particular, in this example, only one of the two-sided chamfered portions 3bB and 3bF is ground simultaneously with the outer peripheral surface of the outer ring after the heat treatment, so that the surface roughness is made different. Absent.

Figure 7 Hasa et al shows the other references proposed example. In the rolling bearing 1 of this reference proposal example , the axial dimensions XB and XF of the chamfered portions 3bB and 3bF on the outer peripheral surface of the outer ring 3 on the outer peripheral surface of the outer ring 3 are made different (XB> XF). Thus, the shapes of the finished forms of the double-sided chamfers 3bB and 3bF are different from each other, and the step HF between the end faces between the inner and outer rings 2 and 3 on the front side and the end face between the inner and outer rings 2 and 3 on the back side The step HB is set to be the same. Other configurations are the same as those of the reference proposal example of FIG.

  Thus, by setting the step HF on the end surface between the inner and outer rings 2 and 3 on the front side and the step HB on the end surface between the inner and outer rings 2 and 3 on the back side as shown in FIG. When used as such combination bearings 10 and 11, preloading is performed by fitting with the shaft and fitting with the housing only by distinguishing the direction of the contact angle without worrying about the arrangement order of the rolling bearings 1. The set combination bearing can be easily assembled. However, even in this case, the condition that the rolling bearing 1 is a bearing whose outer diameter / inner diameter dimension tolerance is controlled is the same as that of the conventional rolling bearing.

Incidentally, the upper you施形status and the references proposed example is a rolling bearing 1 has been explained the case of angular contact ball bearing, the invention is not limited to angular contact ball bearings, seals and, cage, for lubrication The structure and the like can also be applied to a bearing having axial (front and back) directionality.

  FIG. 8 is a sectional view of a spindle device for machine tools using the combined bearings 10 and 11 of FIGS. The spindle device 21 is for high-speed rotation, and in the housing 22, the front side of the main shaft 23 (left side in the figure) is supported by the combination bearing 11 in FIG. 3, and the rear side of the main shaft 23 (right side in the figure). Is supported by the combination bearing 10 of FIG. A tool is attached to the front side end of the main shaft 23, or a chuck for gripping a workpiece is attached. A motor 24 that is a built-in motor is provided at an intermediate portion of the main shaft 23, and the main shaft 23 is rotationally driven by the motor 24. The motor 24 includes a rotor 25 fixed to the main shaft 23 and a stator 26 provided on the inner periphery of the housing 22 with respect to the rotor 25. The front combination bearing 11 is assembled with a preload applied in order to ensure rigidity. The housing 22 has a double structure having an inner peripheral housing 22A and an outer peripheral housing 22B in which oil grooves 27 are formed on the outer periphery. The combined bearing 10 serving as a rear side bearing has an inner ring fastened and fixed to the main shaft 23 by an inner ring fixing nut 28, and an outer ring is fixed in a rear side member 22 </ b> C of the housing 22.

  As described above, the spindle device 21 includes the combined bearings 10 and 11 in which the rolling bearings 1 in which the front and back chamfered portions 3bB and 3bF on the outer peripheral surface of the outer ring 3 are different from each other are arranged in the axial direction. Since the main shaft 23 is supported, the direction of the contact angle of the rolling bearing 1 can be easily visually recognized from the outside regardless of before and after the assembly work of the rolling bearing 1.

DESCRIPTION OF SYMBOLS 1,1A-1F ... Rolling bearing 2 ... Inner ring 3 ... Outer ring 2a, 3a ... Raceway surface 3bB, 3bF ... Chamfer part 10 of outer ring ... Combination bearing 21 ... Spindle device 23 ... Main shaft XB, XF ... Axial direction of chamfer part Dimensions RB, RF ... Corner radius R of chamfered portion YB, YF ... Radial dimension of chamfered portion SRB, SRF ... Surface roughness of chamfered portion HB, HF ... End surface step between inner and outer rings

Claims (6)

Inner ring, outer ring, and a plurality of rolling elements interposed between the raceway surfaces of these inner and outer rings, and the internal structure or function has directionality on the front side and back side, and two or more are arranged in the axial direction as a combined bearing In the rolling bearing used,
Rolling bearing is characterized in that different for each other physicians for the surface roughness of the finish-shaped state of the chamfered portion of the front side and the rear side of the outer peripheral surface of the outer ring. In claim 1 , when the surface roughness of the chamfered portion on the front side among the chamfered portions on the front side and the backside is SRF and the surface roughness of the chamfered portion on the back side is SRB, these both surface roughness SRF , SRB,
SRF ≦ Ra0.8
And Ra1.6 ≦ SRB ≦ Ra25
Or SRB ≦ Ra0.8
And Ra1.6 ≦ SRF ≦ Ra25
Rolling bearing set to satisfy the above relationship. In claim 1 , the difference in surface roughness between the chamfered portion on the front side and the backside is that one of the chamfered portions is heat-treated for cutting finish, and the other chamfered portion is outside the outer ring after heat treatment. Rolling bearings that differ from each other by having the same grinding finish as the diameter part. In any one of Claims 1 thru | or 3 , there is a level | step difference which goes into / out of an axial direction mutually in the end surface of an inner ring | wheel and the end surface of an outer ring | wheel, the level | step difference of the end surface between the inner and outer ring | wheels in a front side, Rolling bearings with the same step on the end face between the inner and outer rings. A combination bearing comprising a plurality of rolling bearings according to any one of claims 1 to 4 arranged in contact with each other in an axial direction. A spindle device for a machine tool, wherein a plurality of the rolling bearings according to any one of claims 1 to 4 are installed as a combination bearing for supporting a main shaft.

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