JP5092383B2 - Ball bearing for machine tool main spindle - Google Patents

Description

The present invention, milling, turning, grinding machines, in a machine tool represented by lapping, turning, grinding, about the spindle body swivel unit for ball bearings of a machine tool or the like is performed lapping.

When a spindle turning device for turning the spindle is incorporated in a machine tool such as a milling machine, a lathe, or a grinding machine, the work piece (workpiece (workpiece) is attached to the bearing that is used in the rotation support portion of the spindle turning device. ) Processing accuracy (for example, roundness, cylindricity, inner and outer diameter dimensional accuracy), processing surface quality (for example, processing surface glossiness, texture, etc.), processing surface roughness, etc. The following functions are required.
(1) High accuracy (high rotation accuracy)
(2) High rigidity (3) Low torque, low heat generation In particular, machine tools with a numerical control function (so-called NC machine tools) have been occupying most recently, and various machining conditions can be achieved with a single machine tool. In addition to NC machine tools such as NC lathes, NC milling machines, and machining centers, complex NC machine tools with machining center functions added to NC lathes have also appeared. Multi-function machine tools such as machining centers and complex NC machine tools have more machine components than single-function machine tools, and the floor space and height space required by one machine is large. . Therefore, in addition to satisfying the functions (1) to (3) described above, components such as bearings are further required to save space.

In such a multi-function machine tool, it is considered to achieve multi-functionality by turning a spindle on which a tool is mounted, and as a bearing used for such a spindle turning device of a machine tool, The following formats are used.
(1) Cross roller bearing (see Fig. 31)
As shown in FIG. 31, the cross roller bearing has a structure in which a large number of cylindrical rollers 3 are arranged between an inner ring 1 and an outer ring 2 so as to be able to roll. It can receive axial load and moment load in both directions and save space.

However, in the cross roller bearing, the rolling element is a roller, and the rolling contact surface of the roller 3 is in line contact with the raceway grooves 1a and 2a, so that the torque is large, and when the roller is incorporated in a shaft or housing. Due to slight deformation, the contact state of the line contact portion becomes unstable, and torque unevenness is likely to occur. In addition, for a spindle turning part of a machine tool, a preload is often applied to the bearing in order to achieve high accuracy and high rigidity, but in this case, the torque unevenness due to the above-described deformation is further increased.
(2) Four-point contact ball bearing (see Fig. 32)
As shown in FIG. 32, the four-point contact ball bearing has a configuration in which a large number of balls 6 are arranged between the inner ring 4 and the outer ring 5 so as to be able to roll. It can receive axial load and moment load in both directions, and can save space.

In the case of a four-point contact ball bearing, the rolling element is a ball, so when receiving a pure axial load, or when the axial load is superior to the radial load, the torque is smaller than the cross roller bearing of the same dimension, but against the axial load. When the radial load is dominant, or when receiving a pure radial load, each ball 6 contacts the raceway grooves 4a and 5a at four points, so that the spin slip between the ball 6 and each raceway groove 4a and 5a is large, and the torque is still large. large. In addition, as with the cross roller bearing, for the spindle turning part of a machine tool, a preload is often applied to the bearing in order to achieve high accuracy and high rigidity. In this case, the ball 6 always has inner and outer ring raceway grooves. Since it contacts 4a and 5a at four points, the torque further increases.
(3) Two-row combination ball bearing (see Fig. 33)
As shown in FIG. 33, the two-row combination ball bearing has a configuration in which an angular ball bearing or the like in which a plurality of balls 9 are arranged between the inner ring 7 and the outer ring 8 so as to be able to roll is combined in two rows. In the case of two-row combination ball bearings, the ball 9 and the raceway grooves of the inner and outer rings 7 and 8 are in two-point contact in each single-row bearing, so although torque can be reduced, the shaft is twice that of the single-row bearing. Directional space is required, which is inferior to cross roller bearings and 4-point contact ball bearings in terms of compactness.

  Furthermore, there is a two-row combination ball bearing having a configuration in which an extremely thin deep groove ball bearing or an angular ball bearing (see FIG. 34) is combined for the purpose of space saving. When a two-row combination bearing combined with an extremely thin ball bearing as described above is used to rotatably support the rotating shaft on the housing, it is usually formed at the end of the shaft 11 as shown in FIG. The inner ring 7 of the two-row combination bearing is fitted to the stepped portion 12 and the free end of the inner ring 7 is pressed by the inner ring presser 14 fastened to the end portion of the shaft 11 by the bolt 13, whereby the rotating shaft 11 has two rows. The inner ring 7 of the combined bearing is fixed, and the outer ring 8 of the two-row combined bearing is fitted into a step 16 formed at the end of the housing 15 covering the rotating shaft 11, and the free end of the outer ring is connected to the end of the housing 15. The outer ring 8 of the two-row combination bearing is fixed to the housing 15 by being pressed by the outer ring presser 18 fastened by the bolt 17.

For this reason, when an ultra-thin deep groove ball bearing or an angular ball bearing shown in FIG. 34 is applied as a two-row combination bearing inserted between the rotary shaft 11 and the housing 15, it is advantageous in terms of space saving. The ring thickness of the inner ring 7 and the outer ring 8 is very thin, and the rigidity of the inner ring 7 and the outer ring 8 is low, so that the processing accuracy is difficult (particularly roundness), and as described above, the inner ring 7 and the outer ring 8 are The rotary shaft 11 and the housing 15 are fitted together, and are pressed by the inner ring retainer 14 and the outer ring retainer 18 to be fixed to the rotational shaft 11 and the housing 15. Therefore, when the two-row combination bearing is assembled, that is, to the rotational shaft 11 and the housing 15. And is easily deformed when pressed by the inner ring presser 14 and the outer ring presser 18, and there is a problem that it takes time and effort to secure the assembly accuracy. Also, depending on the case, the raceway grooves of the inner ring 7 and the outer ring 8 may be distorted due to deformation at the time of assembling, and an uneven load may be applied between the contact portions between the balls 9 and the raceway grooves, or the smooth rolling motion of the balls 9 may be hindered. As a result, there may be a problem that it is damaged by a short-term operation.
(4) Two-row combination tapered roller bearing (see Fig. 36)
As shown in FIG. 36, the two-row combined tapered roller bearing has a tapered roller bearing 20 in which a plurality of tapered rollers 24 are disposed between an inner ring 21 and an outer ring 22 via a cage 23 so as to be able to roll. Are combined in two rows via an inner ring spacer 25 and an outer ring spacer 26. In the tapered roller bearing, like the cross roller bearing, the rolling element is a roller, the rolling contact surface of the roller 24 is in line contact with the raceway groove, and the end portion of the roller 24 and the collar portion 27 of the inner ring 21. Because of the sliding contact, the torque increases, and more than twice the axial space of the single row bearing is required. In addition, in order to achieve high accuracy and high rigidity for the spindle turning part of a machine tool, a preload is often applied to the bearing, but in this case, the torque is further increased.

  As a conventional spindle turning device of a machine tool, for example, a first half head that turns with respect to a machine structure about a vertical first axis, and an inclined plane that is inclined by 35 ° with respect to a horizontal plane to support a tool spindle A second half head coupled to the first half head via a guide bearing and pivoting relative to the first half head about a second axis perpendicular to the inclined plane; a first half head; 2 A direct motor for individually turning the half head, and a tool spindle in a state in which the center axis is at an elevation angle with respect to a horizontal plane by turning the second half head from a state in which the center axis is vertical. A spindle head that can rotate between two axes is known (for example, see Patent Document 1).

As an example of the rotary table, a table is fitted and inserted into a support shaft standing at the center of the base via a distributor, and this table is rotatably supported on the base via a cross roller bearing. A rotary indexing device in which a table is rotationally driven by a worm gear or a direct motor to perform rotational indexing is known (for example, see Patent Document 2).
JP-T-2004-520944 (first page, FIGS. 1 to 4) JP-A-10-29125 (second page, FIG. 1)

  As described above, by adopting the configuration described in Patent Document 1 and Patent Document 2, 5-axis machining (holding the work material (workpiece)) that enables various machining of the upper surface in addition to the four side surfaces is possible. Although it is possible to manufacture machining centers with the same function as machining centers and NC lathes and machining centers, the number of machine tools of this type is increasing. Whichever configuration is adopted, the performance of the support bearing that supports the rotation has the most influence on the characteristics such as the rotation accuracy and rigidity of the rotation mechanism section.

Further, in order to achieve the above-described configuration, the space for the components around the swivel mechanism must be increased, and thus further space saving is required. Furthermore, in order to reduce the power for swinging the entire main shaft as much as possible and to save energy, it is necessary to reduce the weight and reduce the inertia by making the turning mechanism portion compact.
However, as described above, when a cross roller bearing, a four-point contact ball bearing, a two-row combination ball bearing, a two-row combination tapered roller bearing or the like is applied as a support bearing, various problems are caused. There is an unsolved problem that it is not possible to configure a ball bearing for a main spindle turning part corresponding to a recent machine tool with a complex tendency while maintaining or improving the functions (1) to (3).

Therefore, the present invention has been made by paying attention to the unsolved problems of the above-described conventional example, and it is possible to provide a machine tool having a recent trend toward compounding while maintaining or improving the functions (1) to (3). and its object is to provide a corresponding spindle body turning unit for ball bearings.

In order to achieve the above object, a main spindle main body turning part ball bearing of a machine tool according to claim 1 is provided with a base and a main spindle main body to which a main shaft that is rotatable with respect to the base and rotates a tool is attached. If, have a drive source for driving the main shaft body, the pivot axis is different machine tools of the spindle body and the rotation axis of the spindle, it is provided between the base and the spindle body, the outer ring A ball bearing for a main spindle body turning part of a machine tool in which a large number of balls are rotatably arranged between a raceway groove and a raceway groove of an inner ring, the ball bearing comprising at least two single row ball bearings The cross-sectional dimension ratio (B / H) between the axial cross-sectional width B and the radial cross-sectional height H of the single row ball bearing is (B / H) <0.63, and the ball bearing is Any one of the outer ring and the inner ring is fastened and fixed to the base, and the spindle main body is Preload by wheel and the inner ring of the other is fastened is characterized by being granted.

In addition, a ball bearing for a main spindle body turning portion of a machine tool according to claim 2 includes a base, a main spindle body attached to a main spindle that is rotatable with respect to the base and rotates a tool, and the main spindle body. It has a drive source to be driven, at a pivot axis and is different from the machine tool of the spindle body and the rotation axis of the spindle, provided, raceway groove and the inner ring raceway of the outer ring between the base and the main shaft body A ball bearing for a main spindle body turning part of a machine tool in which a large number of balls are rotatably arranged between grooves, wherein the ball bearing has a double row ball bearing, and the double row ball bearing axial cross-sectional width B 2 and the radial section sectional size ratio between the height of H 2 (B2 / H2) is the (B2 / H2) <1.2, wherein the ball bearing, the relative to the base One of the outer ring and the inner ring is fastened and fixed, and the other of the outer ring and the inner ring is fixed to the main spindle body. It is characterized in that the preload is applied by being fit with fixed.

Et al of the spindle body turning ball bearing of a machine tool according to claim 3 is the invention according to claim 1 or 2, relates to the axial direction of the ball bearing, the drive source and the main shaft body of the ball bearing It is as wherein the ball bearing is arranged so as to be positioned on both sides.
In the invention according to claim 1, for example, referring to FIG. 3, a single row in which a large number of balls 103 are rotatably arranged between a rolling groove 101 a of the outer ring 101 and a rolling groove 102 a of the inner ring 102. In the ball bearing 100, the axial sectional width B and the radial sectional height H (= (outer ring outer diameter D−inner ring inner diameter d) / 2) have a sectional dimension ratio (B / H) of (B / H) <0. .63.

Here, the reason why the cross-sectional dimension ratio (B / H) in the invention according to claim 1 is set to (B / H) <0.63 is as follows.
27 and FIG. 28 show the standard thin ball bearings (bearing inner diameter: Φ203.2 mm, bearing outer diameter: Φ254 mm, bearing width: 25.4 mm, the cross-sectional dimension ratio (B / H ) = 1) as a reference, when the bearing inner diameter is changed without changing the bearing outer diameter and bearing width (that is, when the value of (B / H) is changed) deformation characteristics (see FIG. 25: illustrates the inner ring) and radial cross-sectional secondary moment I (see Figure 26): shows the I = bh ^3/12) result of comparison.

According to FIGS. 27 and 28, when (B / H) = 0.63, the change in the stiffness increase rate gradient is noticeable. That is, the increase in the cross-sectional secondary moment I becomes remarkable, and the decrease in the deformation amount of the inner and outer ring in the radial direction is saturated.
Therefore, in the present invention, bearing deformation such as roundness and uneven thickness can be prevented, which can be prevented by lathe processing during inner and outer ring production and processing force during polishing, which is a problem with conventional ultra-thin bearings. Can be improved.

In addition, when assembled in a shaft or housing (especially when assembled by clearance fitting with the shaft or housing), deformation of the inner and outer rings when the bearing is fixed with inner ring retainers or outer ring retainers (especially with roundness) In addition to torque failure and rotation accuracy failure caused by deformation, problems such as increased heat generation, wear, and seizure can be prevented.
That is, as compared with the conventionally used ultra-thin ball bearings, it is possible to achieve both space saving and high accuracy.

FIG. 29 is a comparison data of the relative inclination angles of the inner and outer rings when a moment load is applied to each of the single row product of the present invention and the cross roller bearing.
Here, the main dimensions of the measuring bearing are
Invention product:
Inner ring inner diameter: Φ170
Outer ring outer diameter: Φ215
Single unit width: 13.5mm
Rolling element pitch circle diameter: Φ192.5
Contact angle 35 °
(B / H = 0.60)
Cross roller bearing:
Inner ring inner diameter: 130
Outer ring outer diameter: 230
Assembly width: 30mm
Rolling element pitch circle diameter: Φ189.7
It is.

As is clear from FIG. 29, the moment rigidity comparison data for both the present invention product and the cross roller bearing in which the pitch circle diameters of the rolling elements are substantially the same are about It was confirmed that the moment rigidity was maintained 1.3 times.
In addition to the above experiments, the product of the present invention and the cross roller bearing were assembled into the shaft and housing, and then rotated at a low speed by a motor (belt drive). In the case of the cross roller bearing, rotation irregularity due to torque fluctuation was actually confirmed.

On the other hand, in the standard ball bearings whose dimension series prescribed by the International Organization for Standardization (ISO) are 18 (for example, 6820), 19 (for example, 6924), 10 (for example, 6028), 02 (for example, 7224A), 03 (for example, 7322A) When the inner diameter of the bearing is φ5 mm to φ500 mm, the cross-sectional dimension ratio (B / H) is set to 0.63 to 1.17.
Therefore, the width of the cross-sectional dimension ratio (B / H) of these ball bearings is set to about ½ times the maximum value of 1.17, that is, less than 0.63, which is the narrowest in conventional standard single row ball bearings. The ball bearings according to claim 1 can be arranged in combination with each other within a space narrower than that of the conventional ball bearing and within the axial space of the conventional standard single row ball bearing.

For example, if the sectional dimension ratio (B / H) of a conventional ball bearing is (B / H) = 0.9, the sectional dimension ratio (B / H) of the bearing of the present invention is (B / H) = 0. .45. In the case of this example, it is not necessary for the two ball bearings to be combined to have the same cross-sectional dimension ratio (B / H). For example, one may be 0.50 and the other may be 0.40.
Single-row ball bearings are difficult to apply preload or moment load in one row, but with multiple rows of two or more rows, radial load, axial load and moment load can be applied. It becomes possible to do.

Further, since each ball always contacts the inner and outer raceway grooves at two points, an increase in torque due to a large spin of the ball can be suppressed as in a four-point contact ball bearing. Compared to a bearing or a two-row combined tapered roller bearing, the rolling resistance is reduced, so a reduction in torque can be realized.
Furthermore, when the width dimension is about half that of the conventional standard single-row ball bearing, the ball diameter is also about half that of the conventional ball bearing. Increased against ball bearings. Also, when used for the spindle turning part of a machine tool, since it is a swinging rotation condition, rolling fatigue life time becomes a problem in practice even if the load capacity of the bearing is reduced by reducing the ball diameter. There is no.

In the invention according to claim 2 , for example, referring to FIG. 21, a large number of balls 203 roll between the double row raceway grooves 201 a and 201 b of the outer ring 201 and the double row raceway grooves 202 a and 202 b of the inner ring 202. In the double-row ball bearing 200 disposed freely, the sectional dimension ratio (B2 / H2) between the axial sectional width B2 and the radial sectional height H2 (= (outer ring outer diameter D2-inner ring inner diameter d2) / 2). ) For (B2 / H2) <1.2.

  In the double row ball bearing, by setting the cross-sectional dimension ratio (B2 / H2) as described above, the conventional standard is the same as when the single row narrow ball bearing according to claim 1 is combined in two rows. It becomes possible to arrange the double row ball bearing according to claim 3 in the axial width space of the single row ball bearing, and it is also possible to apply a preload or apply a moment load. Other functions and effects are the same as in the case where the single row narrow ball bearings according to claim 1 are combined in two rows.

  FIG. 30 is a comparison of calculated moment stiffness of various bearings. For the same size (calculation example is equivalent to bearing name No. 7906A (contact angle 30 °) and the inner and outer diameter dimensions are the same: inner ring inner diameter φ30 mm, outer ring outer diameter φ47 mm), the single row narrow angular contact ball according to claim 1 The present invention examples A to E in which the bearings (contact angle 30 °: calculation example of the total ball bearing) are combined in two rows and the raceway radius of curvature of the inner and outer rings are changed are all cross roller bearings, standard double row angular combinations The moment rigidity is larger than that of the ball bearing and the four-point contact ball bearing. For example, the present invention example B can maintain moment rigidity 2.4 times that of a cross roller bearing, 1.9 times that of a standard two-row combination angular ball bearing, and 3.3 times that of a four-point contact ball bearing. is there.

The design preload clearances are -0.010 mm for the invention examples A to E, standard two-row combination angular contact ball bearings and 4-point contact ball bearings, and -0.001 mm for the cross roller bearings. (If the pre-load setting is less than -0.001 mm with a cross roller bearing, the torque may be excessive and may be unusable for practical use).
The appropriate ball diameter of the narrow ball bearing according to the present invention varies depending on whether or not a seal or the like is attached, but in order to increase rigidity, if the ball diameter is extremely reduced, the ball and the inner and outer ring raceway grooves Since the surface pressure between the contact portions increases and the pressure scar resistance decreases, the bearing width (B) or (B2 / 2) is preferably approximately 30% to 90%.

Furthermore, when the present invention is applied to an angular ball bearing, the contact angle of the bearing is selected depending on the required rigidity (for example, moment rigidity) and the required torque, but is preferably in the range of approximately 10 to 60 °.
Furthermore, the contact angle of each combined single row bearing or the contact angle between each row in the case of a double row bearing may be changed as necessary in accordance with the direction and magnitude of the load.

  Further, the radius of curvature of the inner and outer ring raceway grooves is 51 to 60% Da (Da: ball diameter), preferably 52 to 56% Da, more preferably 52 to 54%, depending on the required rigidity and torque characteristics. It is about Da. Further, the radius of curvature of each raceway groove of the inner and outer rings may not be the same, or may be different between single row bearings to be combined or between rows of double row bearings.

According to the present invention, in the spindle main body turning part ball bearing provided between the base of the machine tool and the main spindle main body, in the case of a single row ball bearing, the axial sectional width B and the radial sectional height H In the case of a double row ball bearing, the sectional ratio (B2 / H2) between the axial sectional width B2 and the radial sectional height H2 is (B / H) <0.63. By setting (B2 / H2) <1.2, it is possible to receive radial load, axial load in both directions, and moment load, as well as higher accuracy (higher rotation accuracy), higher rigidity, and lower torque. In addition, it is possible to reduce the heat generation, and to obtain an effect that further space saving can be achieved. Then, the spindle turning device itself can be saved in space by applying the spindle main body turning portion ball bearing having the above effects to the spindle turning portion to constitute the spindle turning device.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
FIG. 1 is a side view in cross section of a main portion showing a first embodiment (corresponding to claim 1 or 3) when the spindle turning device of a machine tool according to the present invention is applied to, for example, a 5-axis machining center. is there.
In the figure, reference numeral 30 denotes a spindle turning device for a machine tool, which is a base 31 fixed to a fixed portion of a machining center, a turning base 32 rotatably supported by the base 31, and a rotating base 32 attached to the base 31. The main shaft body 33 is provided.

The base 31 has a housing recess 34 that houses a swivel base 32 that is recessed from the center of the left end surface to the right side. The swivel base 32 has a main shaft body swivel ball bearing 35 according to the present invention in the housing recess 34. It is rotatably supported via.
Here, the swivel pedestal 32 has a disc portion 37 which is opposed to the left end surface of the base 31 and has a flat mounting surface 36 formed at the left end, and protrudes from the right end of the disc portion 37 and protrudes from the right end of the disc main body swivel portion A step portion 38 that holds the inner ring of the bearing 35 and a step portion 40 that fits and holds the worm wheel 39 are formed, and a protruding portion 42 that is formed with a recess 41 for reducing the weight from the right end of the central portion to the left. Have.

Then, the inner ring presser 43 formed integrally with the worm wheel 39 is tightened with a bolt 44 in a state where the inner ring of the spindle main body turning part ball bearing 35 is engaged with the stepped part 38, whereby the main spindle body is fixed to the stepped part 38. The inner ring of the turning ball bearing 35 is fixed.
On the other hand, the outer ring of the ball bearing 35 for the main spindle main body turning part is fitted into a step 45 formed in the receiving recess 34 of the base 31, and the outer ring presser 46 disposed on the left end surface side of the base 31 is turned, for example. It is fixed to the base 31 by bolting with a bolt 47 inserted through a through hole (not shown) formed in the disc portion 37 of the base 32.

Further, the worm wheel 39 is engaged with a worm 48 connected to a rotational drive source such as a motor. By rotating the worm 48, the swivel pedestal 32 is vertically aligned with, for example, a tool mounting surface of a main spindle body 33 described later. When the downward angle is 0 °, the main spindle body 33 is swung (oscillated) about ± 100 ° in the front-rear direction.
Further, the main spindle body 33 is integrally formed with a main spindle 52 equipped with a rotation drive source for rotating a tool with a tool mounting surface 51 for attaching a tool (not shown) such as an end mill or a drill as a lower side, and a side surface of the main spindle 52. And a mounting plate portion 53 bolted to the mounting surface 36 of the disc portion 37 of the swivel base 32 formed.

Next, the operation of the first embodiment will be described.
Now, for example, as shown in FIG. 1, with the main spindle body 33 positioning the tool mounting surface 51 at 0 ° vertically downward, a tool such as an end mill or a drill is mounted on the tool mounting surface 51 of the main spindle 52 and built-in. The tool can be cut as a vertical machining center by moving the jig and the work material (workpiece) relative to each other while being driven to rotate at a high speed by the rotating drive source.

  After this cutting process is completed, the spindle body 33 is rotated + 90 ° in the forward direction by rotating the pedestal 32 by + 90 ° in the forward direction, for example, by rotating the worm 48 forward by a rotational drive source (not shown). The tool turns to the front side, and in this state, the jig and the work material (workpiece) are moved relative to each other, whereby cutting can be performed as a horizontal machining center.

Similarly, the worm 48 is reversely driven by a rotational drive source, and the swivel base, for example, the swivel base 32 and the main spindle body 33 are swung back by −90 °, and then the jig and the work material are moved relative to each other. Thus, cutting can be performed as a horizontal machining center.
In this way, by applying the main spindle main body turning section ball bearing 35 according to the present invention to the main spindle turning section of the main spindle turning device 30, the main spindle main body turning section ball bearing 35 has a radial load and an axial axial direction as will be described later. In addition to being able to receive loads and moment loads, it is possible to achieve high accuracy (high rotational accuracy), high rigidity, low torque and low heat generation, as well as further space saving. Therefore, the spindle turning device 30 itself can also save space.

In the first embodiment, the case where the swivel base 32 is rotationally driven by the worm gear has been described. However, the present invention is not limited to this, and the rotational base 32 is rotationally driven by applying a bevel gear mechanism or another gear mechanism. Further, as shown in FIG. 2, the worm wheel 39 and the worm 48 are omitted, the stator 61 disposed on the inner peripheral surface of the housing recess 34 of the base 31, and the swivel base 32 facing the stator 61. Alternatively, the swivel base 32 may be directly driven to turn by a direct motor 63 including a rotor 62 disposed on the outer peripheral surface of the protrusion 42. In the case of this Figure 2 is preferably applied to one side seal and retainer with ball bearings illustrated in Figure 12 to be described later as a spindle body turning unit for ball bearings 35. Further, the swivel base 32 has a base 64 that holds the main spindle body swivel ball bearing 35 and the rotor 62, and a mounting plate 65 that also serves as an inner ring presser of the main spindle main body swivel ball bearing 35 that is bolted to the base 64. It consists of and.

Here, the direct motor 63 is not limited to the outer rotor type shown in FIG. 2, but an inner rotor type in which a rotor is provided on the inner peripheral surface of the recess 41 of the protrusion 42 and a stator is provided inside the rotor. You may make it comprise.
Moreover, in 1st Embodiment, although the case where the rotation base 32 was rotatably supported in the accommodation recessed part 34 formed in the base 31 was demonstrated, it is not limited to this, The outer side of the base 31 In addition, the swivel base 32 may be rotatably supported through the spindle main body swivel ball bearing 35 according to the present invention.

Furthermore, in the first embodiment, the case where the present invention is applied to a machining center has been described. However, the present invention is not limited to this, and in order to add a machining center function to a lathe, a milling machine, a grinding machine, a lapping machine, or the like. The present invention can be applied to any composite type machine tool provided with a spindle turning device for turning the spindle.
Furthermore, the main spindle turning device 30 is not limited to the above-described configuration, and any configuration may be adopted as long as the main spindle body 33 is supported via the main spindle main body turning portion ball bearing. Can do.

Next, a specific example of the main shaft main body turning portion ball bearing 35 according to the present invention applied to the main shaft turning portion of the main spindle turning device 30 will be described.
The main spindle body swivel ball bearing 35 includes: (a) rotating the main spindle body 33 installed on the turning pedestal 32 of the main spindle turning device 30 with high accuracy (runout accuracy); and (b) reducing the main spindle body 33 to a low level. It is required to smoothly swing and rotate with torque, and (c) to reduce the displacement of the entire main spindle body with respect to the load during workpiece processing (high rigidity). In addition to the moment load due to the weight of the spindle related parts and the inertia load that occurs during turning acceleration / deceleration, the radial bearing, axial load, and moment load that occur according to the processing conditions are independent on the spindle body swivel ball bearing 35. Or these loads may act in combination.

FIG. 3 shows a first embodiment (corresponding to claim 1) of the main ball main body turning part ball bearing according to the present invention. In the spindle main body swivel ball bearing (single row ball bearing) 100 shown in the same figure, a large number of balls 103 are rotatably arranged between a raceway groove 101a of an outer ring 101 and a raceway groove 102a of an inner ring 102. In the single ball angular contact ball bearing 100, the sectional dimension ratio (B / H) between the axial sectional width B and the radial sectional height H (= (outer ring outer diameter D−inner ring inner diameter d) / 2) is set. (B / H) <0.63. The reason for this has been described in detail with reference to FIG. 29 in the section of means for solving the above-described problem, and therefore description thereof is omitted here.

Here, in this embodiment, as shown in FIG. 4, a case where the angular ball bearing 100 is replaced with a double row combination angular ball bearing of 7940A (contact angle 30 °) is taken as an example.
Since the 7940A angular contact ball bearing has an inner ring inner diameter d: Φ200 mm, an outer ring outer diameter D: Φ280 mm, and an axial sectional width (bearing single body width) B is 38 mm, the sectional dimension ratio (B / H) = 0.95. . Therefore, in the angular ball bearing 100 of the present embodiment, the cross-sectional dimension ratio (B / H) = 0.475 (the inner ring inner diameter and the outer ring outer diameter remain the same, and the axial sectional width (bearing unit width) B is 19 mm). It is said. As a result, radial load, axial load in both directions, and moment load can be received, as well as high accuracy (high rotational accuracy), high rigidity, low torque and low heat generation can be achieved. Space saving of 1/2 in the axial dimension can be achieved.

Of course, the cross sectional dimension ratio (B / H) of the angular ball bearing 100 may be set to be less than 0.475 or more than 0.475 (provided that (B / H) <0.63) as necessary. Absent. Incidentally, the contact angle of the angular ball bearing 100 is, for example, 30 °.
In this embodiment, the pitch circle diameter of the balls 103 is as shown in the following equation (1). However, when it is desired to increase the moment rigidity by increasing the number of balls per row of the bearing, the following equation (2) And the pitch circle diameter of the ball 103 may be shifted to the outer ring side as shown in FIG. 5, or the following formula (3) may be adopted as necessary to change the pitch circle diameter of the ball 103 to the inner ring. You may shift to 102 side (not shown).
Ball pitch circle diameter = (inner ring inner diameter + outer ring outer diameter) / 2 (1)
Ball pitch circle diameter> (inner ring inner diameter + outer ring outer diameter) / 2 (2)
Ball pitch circle diameter <(inner ring inner diameter + outer ring outer diameter) / 2 (3)
Further, as shown in FIG. 6, the ball pitch circle diameters of the combined left and right ball bearings may not be the same value as shown in FIG. 6, and the diameters of the balls 103 in the combined left and right ball bearings are set to the same value. It does not have to be. In addition, the sectional dimension ratio (B / H) of the two ball bearings to be combined is not the same. For example, the smaller ball diameter is (B / H) = 0.35, and the larger ball diameter is (B / H). ) = 0.60. Furthermore, the axial pitch of the balls 103 does not have to be the center in the axial direction, and the axial pitch of the balls 103 may be shifted in the axial direction in order to secure the distance between the action points of the moment and the installation of seals and cages. Good.

FIG. 7 shows a combination of two rows of angular ball bearings 100 with an annular seal body 104 mounted on one end in the axial direction.
After the angular ball bearings 100 having the annular seal body 104 mounted on one end in the axial direction are combined in two rows and mounted on a machine or the like (combined with the seal mounting surface facing outward), the external ball bearing 100 is used from outside during use of the bearing. It is possible to prevent entry of foreign matter, dust, etc. and leakage of the enclosed grease to the outside. In this embodiment, the annular seal body 104 is a non-contact type (non-contact with the inner ring 102) inserted into the seal groove 104a of the outer ring 101 and a reinforcing rubber seal (for example, nitrile rubber / acrylic rubber) of the metal core 105. Or fluorine rubber) 106, and an annular seal body 104 is attached only on the side opposite to the combined end face to save space.

FIG. 8 shows an angular ball bearing 100 in which annular seal bodies 104 are mounted at both ends in the axial direction.
After the angular ball bearing 100 having the annular seal body 104 mounted on both ends in the axial direction is attached to a machine or the like, it prevents foreign matter or dust from entering from outside during use of the bearing, Even when it is assembled into the housing, it is possible to prevent intrusion of foreign matter, dust, etc. and leakage of the enclosed grease to the outside. As for the combination, in order to increase the moment stiffness in two rows, it is desirable to adopt a backside combination (the contact angle is in the direction of the letter C in FIG. 4 etc.) that allows the moment action point distance to be increased. .

  If further rigidity is required, as shown in FIG. 9 and FIG. 10, a multi-row combination of three or more rows may be used. For some reason (for example, misalignment is unavoidable when the bearing is installed, the internal load of the bearing is For example, when it is desired to suppress the load as much as possible and to reduce the moment rigidity, as shown in FIG. 11, an arrangement such as a front combination (a contact angle direction is a reverse C) may be used.

Furthermore, in order to apply a moment load or both axial loads, it is necessary to use two or more rows of combined bearings. You can use it.
In this embodiment, the angular ball bearing is used, but other ball bearings such as a deep groove ball bearing may be used. The annular seal body is not the non-contact type shown in FIGS. 7 and 8, but may be a contact type metal core reinforcing type rubber seal (the rubber material is, for example, nitrile rubber, acrylic rubber, or fluorine rubber), or the outer ring 101. A metal shield plate that is swaged into the seal groove may be used. Further, the annular seal body may be inserted by being pushed into the seal groove on the inner ring 102 side, or may be attached by caulking (a structure in contact with or non-contact with the outer ring).

The material of the inner ring 102, the outer ring 101, and the ball 103 is a bearing steel (eg, SUJ2, SUJ3, etc.) under standard usage conditions, but depending on the usage environment, a stainless steel material (eg, SUS440C, etc.) that is a corrosion resistant material. Martensitic stainless steel materials, austenitic stainless steel materials such as SUS304, precipitation hardening stainless steel materials such as SUS630, etc., titanium alloys and ceramic materials (for example, Si ₃ N ₄ , SiC, Al ₂ O ₃ , ZrO _2, etc.) ) May be adopted.

The lubrication method is not particularly limited, and mineral oil-based grease or synthetic oil-based grease (for example, lithium-based or urea-based grease) or oil can be used in a general use environment, and fluorine-based grease or fluorine in high-temperature environment applications. Series lubricants or solid lubricants such as fluororesin and MoS ₂ can be used.
FIG. 12 shows an angular contact ball bearing equipped with a retainer 110 that is mounted with an annular seal body 104 at one end in the axial direction (end opposite to the end face on the combination side) and holds the ball 103 in a rollable manner. 100 is a combination of two rows on the back.

  As the retainer 110, for example, as shown in FIGS. 13 to 16A, an annular portion 111 and one end portion of the annular portion 111 project in the axial direction at a plurality of locations at substantially equal intervals in the circumferential direction. A flexible crown-shaped cage including the pillars 112 and pockets 113 formed between the pillars 112 to hold the balls 103 so as to roll in the circumferential direction is employed. The material of the cage 110 is, for example, a synthetic resin material such as polyamide, polyacetal, or polyphenylene sulfide, and a material in which a reinforcing material such as glass fiber or carbon fiber is mixed into the synthetic resin material is used as necessary.

In this embodiment, in order to increase the load capacity and rigidity of the bearing, the circumferential pitch between adjacent balls 103 is made as small as possible, and the number of balls is increased as much as possible. Furthermore, the axial pitch of the balls 103 is shifted as much as possible to the opposite side of the combination side end surface (FIG. 12: X ₁ > X ₂ ), and the ring portion 111 of the cage 110 is arranged to be on the bearing combination end surface side. In order to increase the moment rigidity, the distance between the operating points can be increased.

In the case of a full-ball bearing, the axial pitch of the balls is not the center of the width but the axial direction of the ball in the left or right direction (bearing alignment end surface side or It can be shifted to the opposite side.
When a ball bearing with a cage is used as a full ball bearing under conditions where the rotation speed tends to vary due to changes in the contact angle of each ball, such as continuous rotation in one direction or a large moment load. It is more effective in terms of low torque, low heat generation, etc.

Furthermore, in this embodiment, if the entrance portion of the pocket portion 113 is slightly smaller than the ball diameter and is provided with a catch (pachin allowance), the ball 103 can be assembled without being dropped when the inner ring 102 and the outer ring 101 are assembled. Easy.
The shape of the cage is not limited to this embodiment, and any type other than the separator type cage disposed between the balls 103 may be used. Also, the material may be a metal material instead of a synthetic resin material.

16 (b) is a crown-shaped cage having the same basic structure as FIG. 16 (a), but the pocket portions 113 adjacent to each other at least at one place in the circumferential direction of the annular portion 111 are cut in advance. And it is set as the structure which gave the predetermined clearance gap between each cut surface.
By adopting such a structure, the rotation is caused by the difference in the thermal expansion coefficient between the cage and the inner and outer rings and the variation in the dimensional accuracy and roundness of the cage (particularly in the case of an embodiment with a large bearing size). Even if the pitch diameter of the moving body and the pitch diameter of the cage deviate from each other, the flexibility in the radial direction due to the cantilever shape and the elastic deformation in the circumferential direction due to the gaps between the cut surfaces (in the circumferential direction) Flexibility), the tension force between the ball 103 and the pocket portion 113 is buffered to prevent the cage from being damaged or worn, and the torque due to the sliding contact resistance between the ball 103 and the pocket portion 113 inner surface. Unevenness and heat generation can be further reduced.

In addition, since the ball bearing for the main spindle body turning part of the present invention has a structurally small ball diameter, the radial thickness of the annular part 111 of the cage cannot be increased (as can be understood from FIG. 12). The cage needs to be positioned by providing an appropriate gap in the gap between the outer diameter of the inner ring and the inner diameter of the outer ring, and the gap between the outer diameter of the inner ring and the inner diameter of the outer ring is approximately proportional to the ball diameter. Furthermore, due to the narrow structure, the gap in the axial direction is also narrow and the thickness in the axial direction must be reduced. For this reason, since the annular portion of the cage is extremely smaller than a standard size bearing and it is difficult to obtain dimensional accuracy such as roundness, the cage structure with the annular portion 111 as shown in FIG. In particular, the effects described above can be obtained with respect to the above-described cage damage and wear prevention effect, and torque unevenness and heat generation reduction.

  Moreover, the intended use is turning rotation, and the centrifugal force is not continuously applied to the cage. Therefore, when the present invention is applied to these uses, even if the cage structure is as shown in FIG. If necessary, the circular portion 111 may have two or more cut portions in the circumferential direction. In this case, it is desirable that the cut portions are equally divided in the circumferential direction as much as possible. In addition, when these ball bearings are applied to the spindle turning device of a machine tool, they are usually used with a preload to increase the rigidity. However, depending on the conditions or for other purposes, allow clearance. May be used.

Further, a modification (corresponding to claim 2) of the above-described first embodiment will be described with reference to FIG.
In this modification, an annular seal body 120 is provided on one side of a single row ball bearing 100 constituted by a single row full-ball angular ball bearing shown in FIG. 1, and a plurality of balls 103 are positioned in the circumferential direction. A container 130 is provided.

That is, as shown in FIG. 17, seal housing grooves 121 and 122 for housing the annular seal body 120 are arranged on one end face on the right side of the outer ring 101 and the inner ring 102, for example.
The annular seal body 120 is composed of a reinforced rubber seal (for example, nitrile rubber / acrylic rubber or fluororubber) 126 reinforced by a metal core 125 formed in an inverted L shape. The rubber seal 126 has a fitting portion 126 a that fits the outer ring 101 on the outer peripheral portion, and a lip portion 126 b that contacts the inner ring 102 on the inner peripheral portion.

  The seal housing groove 121 of the outer ring 101 has a relatively shallow step portion 121a on the right end side of the inclined inner peripheral surface 101b connected to the raceway groove 101a of the outer ring 101, and an annular shape formed in the circumferential direction at the bottom portion of the step portion 121a. It is set as the structure which has the shallow fitting recessed part 121b which pushes in and inserts the fitting part 126a of the seal body 120. FIG. Further, the seal housing groove 122 of the inner ring 102 includes a relatively deep step portion 122a on the right end side on the right side of the raceway groove 102a on the cylindrical outer peripheral surface 102b connected to the left and right ends of the raceway groove 102a of the inner ring, and a bottom surface of the step portion 122a. And a shallow housing recess 122b with which the lip 126b formed on the inner peripheral surface of the annular seal body 120 formed in the circumferential direction contacts.

Furthermore, the retainer 130 has a pair of annular portions 132 a and 132 b extending in the axial direction across the pocket portion 131 that accommodates the ball 103, and these annular portions 132 a and 132 b are the cylindrical outer peripheral surface 102 b of the inner ring 102. Is installed as a guide surface.
The annular portion 132b on the annular seal body 120 side is connected to the intersection edge portion 123 on the inner circumferential surface facing the intersection edge portion 123 formed at the intersection between the cylindrical outer circumferential surface 102b of the inner ring 102 and the seal housing groove 122. A concave groove 133 having a semicircular cross section that avoids contact is formed in the circumferential direction.

  The cage 130 is made of a metal material such as a copper alloy manufactured by cutting, a synthetic resin material such as polyamide, polyacetal, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), or glass fiber or carbon fiber. It is made of a synthetic resin material containing a reinforcing material with a reinforcing material added. When the cage 130 is formed of a resin material, either cutting molding or injection molding can be applied.

  As described above, since the concave groove 133 is formed in the circumferential direction on the inner peripheral surface facing the intersection edge portion 123 formed on the right end side of the guide surface of the cage 130, the intersection edge portion 123 is formed in the cage. The retainer 130 can be reliably prevented from coming into contact with the inner peripheral surface of the ring 130, while ensuring the strength by increasing the width of the annular portion 132b on the annular seal body 120 side to increase the cross-sectional area. Can be reliably prevented.

  In addition, in the case of grease lubrication, the concave groove 133 provided in a part of the guide surface can serve as a reservoir for holding grease, and in addition, since it is located in the vicinity of the guide surface, There is also an effect of appropriately supplying the lubricating oil, and the wear resistance can be maintained for a long time from the viewpoint of the lubrication characteristics. This effect becomes more remarkable when concave grooves 133 and 134 are formed in both annular portions 132a and 132b as shown in FIG.

  Normally, when the annular seal body 120 is disposed on at least one side of the ball bearing 100, the inner diameter surface of the outer ring 101 and the outer diameter surface of the inner ring 102 are used as the guide surfaces of the cage 130. Since the intersection edge portion 123 is formed at a position where the groove 122 is in contact with the groove 122, the cage 130 is worn due to the contact between the intersection edge portion 123 and the annular portion 132b of the cage 130.

In order to prevent the wear of the cage 130, conventionally, when the inner ring guide is used, as shown in FIG. 18, the axial length or width of the annular portion 132b on the intersection edge portion 123 side of the cage 130 is shown. It is considered that the annular portion 132b and the intersection edge portion 123 do not come into contact with each other.
However, in the case of the narrow ball bearing 100 as in this embodiment, there is a problem that the width of the annular portion 132b becomes very thin and sufficient strength cannot be ensured.

  For this purpose, as shown in FIG. 19, it is necessary to increase the width of the annular portion 132b to ensure strength, but in this case, as described above, the intersection with the inner peripheral surface of the annular portion 132b. Since the edge portion 123 is opposed, when the cage 130 is inclined with respect to the guide-side raceway during rotation of the ball bearing 100, the inner peripheral surface of the annular portion 132b is edged to the intersection edge portion 123. As a result, the cage 130 is worn.

In particular, since the seal receiving grooves 121 and 122 are often heat-treated surfaces after cutting, the surface roughness is poor, and burrs are likely to be formed at the intersecting portions that come into contact with the cage 130, so that wear occurs. It's easy to do.
Furthermore, since the ball bearing 100 according to the present invention has a structurally very small ball diameter with respect to the ball pitch circle diameter of the bearing, the cross section of the annular portion 132b of the cage 130 is correspondingly reduced. The radial strength of the cage 130 (the radial strength of the annular portion 132b) is also reduced. In addition to this, the application of the ball bearing 100 according to the present invention is likely to cause a large moment load to be applied during rotation of the bearing, and the bearing is liable to tilt due to its usage conditions. Therefore, due to the change in the contact angle of each ball 103, the revolution speed of each ball 103 varies, and the deformation of the cage 130 due to the tension force between the ball 103 and the pocket portion 131 also increases, so it is easier to hit the edge. Further, the surface pressure of the contact portion also increases and wear tends to proceed.

  However, as described above, in this embodiment, as shown in FIG. 17, the width of the annular portion 132b on the annular seal body 120 side of the cage 130 is increased to increase the cross-sectional area, Since the concave groove 133 is formed in a portion that may contact the intersection edge portion 123 at the boundary with the cylindrical surface 102b serving as the guide surface, even if the cage 130 is inclined, the intersection edge portion 123 and the concave shape are formed. Since a sufficient space can be ensured between the groove 133 and the contact between the concave groove 133 and the intersection edge portion 123 can be surely prevented, and wear of the cage 130 can be surely prevented. .

In the above modification, the case where the annular seal body 120 is disposed on the right side of the ball bearing 100 has been described. However, the present invention is not limited to this, and the annular seal body 120 is disposed on the left side of the ball bearing 100. Alternatively, the annular seal body 120 may be disposed on both sides.
Moreover, although the case where the concave groove 133 formed in the annular portion 132b is formed in a semicircular cross section has been described in the above modification, the present invention is not limited to this, and is not limited to this. Any shape can be used as long as contact with the intersection edge portion 123 such as a shape can be avoided.

Furthermore, although the case where the annular seal body 120 is in contact with the inner ring seal housing groove 122 has been described in the above modification, the present invention is not limited to this, and the non-contact rubber seal that does not contact the inner ring seal housing groove 122 shown in FIG. A metal seal that is caulked in a mold (attached to a metal core) or an outer ring seal groove can be applied.
Furthermore, in the above-described modification, the case where the guide surface of the cage 130 is the outer peripheral surface of the inner ring 102 has been described, but the present invention is not limited to this, and the inner peripheral surface of the outer ring 101 is used as the guide surface. May be.

  Furthermore, in the above-described modification, the case where the concave groove 133 is formed in the annular portion 132b on the annular seal body 120 side of the annular portions 132a and 132b of the cage 130 has been described. However, the present invention is not limited to this. As shown in FIG. 20, as shown in FIG. 20, the annular groove 132 a on the opposite side of the annular seal body 120 also has a concave groove portion in a plane-symmetric position sandwiching the concave groove 133 of the annular portion 132 b and the vertical plane passing through the center of each ball 103. 134 may be provided. As described above, when the concave groove portions are formed in the left and right annular portions 132a and 132b, it is possible to assemble from any direction without confirming the formation position of the concave groove portions of the retainer 130 during the assembly, thereby improving the assembling work. be able to.

Next, a double-row ball bearing for a spindle main body turning portion of a machine tool, which is an example of an embodiment of a second aspect of the present invention (corresponding to claim 4 or 5), will be described with reference to FIG.
In this double row full ball angular contact ball bearing 200, a large number of balls 203 are arranged between the double row raceway grooves 201a and 201b of the outer ring 201 and the double row raceway grooves 202a and 202b of the inner ring 202 so as to roll freely. The cross-sectional dimension ratio (B2 / H2) between the cross-sectional width B2 and the radial cross-sectional height H2 (= (outer ring outer diameter D2—inner ring inner diameter d2) / 2) is (B2 / H2) <1.2. The ball pitch circle diameter is set at the center of the radial section height. The reason for this has been described in detail with reference to FIG. 30 in the section of means for solving the above-described problem, so description thereof is omitted here.

Here, in this embodiment, a case where the double row ball bearing 200 is replaced with a 7940A (contact angle 30 °) double row angular contact ball bearing is taken as an example.
7940A has an inner ring inner diameter d: Φ200 mm, an outer ring outer diameter D: Φ280 mm, an axial sectional width (bearing single body width): B is 38 mm, and thus the sectional dimension ratio (B / H) = 0.95. Therefore, in the angular ball bearing 200 of the present embodiment, the sectional dimension ratio (B2 / H2) = 0.95 (the inner ring outer diameter and the outer ring outer diameter remain the same, and the axial sectional width (bearing unit width): B2 is 38 mm. ) As a result, radial load, axial load in both directions, and moment load can be received, as well as high accuracy (high rotational accuracy), high rigidity, low torque and low heat generation can be achieved. Space saving of 1/2 in the axial dimension can be achieved.

Of course, if necessary, the cross-sectional dimension ratio (B2 / H2) may be set to be less than 0.95 or more than 0.95 (provided that (B2 / H2) <1.2). Incidentally, the contact angle of the angular ball bearing 200 is, for example, 30 °.
FIG. 22 is an example in which the ball pitch circle diameter is shifted to the outer diameter side in the double row full ball angular contact ball bearing 200 in order to increase the moment rigidity, and FIG. FIG. 24 shows an example in which the ball diameter and ball pitch circle diameter of the row are changed. FIG. 24 shows a double row full ball angular contact ball bearing 200 having annular seal bodies 104 mounted on both ends in the axial direction. This is an example in which the pitch circle diameter is shifted to the outer diameter side.

  In any case, in addition to the structure of the annular seal body, the cage, etc. and whether or not it is mounted, the application example related to the structure is the same as the single row ball bearing described in the first embodiment. Moreover, you may use on any conditions of a preload and clearance similarly to the said 1st aspect implementation.

It is the side view which made the principal part the cross section which shows the spindle turning apparatus of the machine tool which is the 1st Embodiment (corresponding to Claim 1 or 3) of the present invention. It is the side view which made the principal part the cross section which shows the modification of the spindle turning apparatus of the machine tool which is the 1st Embodiment (corresponding to Claim 1 or 3) of this invention. 1 is a cross-sectional view of a single-row angular contact ball bearing showing a first embodiment of a main shaft main body turning portion ball bearing according to the present invention. It is principal part sectional drawing which shows the state which combined the single row ball bearing of FIG. 3 with 2 rows. It is principal part sectional drawing which shows the state which combined the single row ball bearing which is other embodiment of the 1st aspect of this invention in two rows. It is principal part sectional drawing which shows the state which combined the single row ball bearing of FIG. 3 and the single row ball bearing which is other embodiment in two rows. It is principal part sectional drawing which shows the state which combined the single row ball bearing which is other embodiment of the 1st aspect of this invention in two rows. It is principal part sectional drawing for demonstrating the single row ball bearing which is other embodiment of the 1st aspect of this invention. It is principal part sectional drawing which shows the state which combined the single row ball bearing of FIG. 3 with 3 rows. It is principal part sectional drawing which shows the state which combined the single row ball bearing of FIG. 3 with 4 rows. It is principal part sectional drawing which shows the state which combined the single row ball bearing of FIG. 3 by 2 row front combination. It is principal part sectional drawing which shows the state which combined the single row ball bearing which is other embodiment of the 1st aspect of this invention in two rows. It is sectional drawing in alignment with the radial direction of a holder | retainer. It is the fragmentary perspective view which looked at the holder | retainer from radial direction inner side. It is the figure seen from the arrow B direction of FIG. (A) is the figure seen from the arrow A direction of FIG. 13, (b) is a figure which shows the modification of (a). It is principal part sectional drawing for demonstrating the single row ball bearing for spindle main body turning parts of the machine tool which is an example of the modification (corresponding to Claim 2) of the 1st aspect of this invention. It is principal part sectional drawing for demonstrating the single row ball bearing for the spindle main body turning parts of a machine tool. It is principal part sectional drawing for demonstrating the modification of the single row ball bearing for the spindle main body turning parts of a machine tool. It is principal part sectional drawing for demonstrating the spindle main body turning part single row ball bearing of the machine tool which is an example of the other modification of the 1st aspect of this invention. It is principal part sectional drawing for demonstrating the double row ball bearing for main axis | shaft main body turning parts of the machine tool which is an example of embodiment of the 2nd aspect (corresponding to Claim 4 or 5) of this invention. It is principal part sectional drawing for demonstrating the double row ball bearing which is other embodiment of the 2nd aspect of this invention. It is principal part sectional drawing for demonstrating the double row ball bearing which is other embodiment of the 2nd aspect of this invention. It is principal part sectional drawing for demonstrating the double row ball bearing which is other embodiment of the 2nd aspect of this invention. It is explanatory drawing for demonstrating the deformation amount of the radial direction of an inner ring | wheel. It is explanatory drawing for demonstrating the calculation method of the cross-sectional secondary moment of an inner ring | wheel. It is a graph which shows the relationship between a cross-sectional dimension ratio (B / H) and the deformation amount of the inner and outer ring | wheels of radial direction. It is a graph which shows the relationship between a cross-sectional dimension ratio (B / H) and a cross-sectional secondary moment I. It is a graph which shows the comparison of the moment rigidity in a single row bearing. It is a graph which shows the comparison of the calculated moment rigidity in various bearings. It is principal part sectional drawing of a cross-roller bearing. It is principal part sectional drawing of a 4-point contact ball bearing. It is principal part sectional drawing of the conventional 2 row combination angular contact ball bearing. It is principal part sectional drawing of the conventional 2 row combination angular contact ball bearing of an ultra-thin wall section. It is sectional drawing which shows the state which attached the conventional 2 rows combination angular contact ball bearing of the ultra-thin wall section to the axis | shaft. It is principal part sectional drawing of the conventional 2 row combination tapered roller bearing.

Explanation of symbols

30 Spindle 31 for machine tool 31 Base 32 Swivel base 33 Spindle main body 35 Spindle body ball bearing 39 Spindle body worm wheel 48 Worm 61 Stator 62 Rotor 63 Direct motor 100 Single row ball bearing 101 Outer ring 101a Outer ring raceway groove 102 Inner ring 102a Inner ring raceway groove 103 Ball 120 Annular seal body 121, 122 Seal receiving groove 123 Intersection edge part 130 Retainer 131 Pocket part 132a, 132b Annular part 133 Concave groove part 200 Double row ball bearing 201 Outer ring 201a, 201b Outer ring raceway groove 202 Inner ring 202a 202b Inner ring raceway groove 203 ball

Claims (3)

A base, a spindle body spindle is mounted for rotating the tool is pivotable relative to the base platform, have a drive source for driving the main shaft body, said spindle body and the rotation axis of the spindle In a machine tool having a different rotation axis, a machine tool is provided between the base and the main spindle body, and a large number of balls are rotatably disposed between the outer raceway groove and the inner raceway groove. A ball bearing for the main spindle body swivel part,
The ball bearing has at least two single row ball bearings;
The cross-sectional dimension ratio (B / H) between the axial cross-sectional width B and the radial cross-sectional height H of the single row ball bearing is (B / H) <0.63,
In the ball bearing, either one of the outer ring and the inner ring is fastened and fixed to the base, and the other of the outer ring and the inner ring is fastened and fixed to the main spindle body, so that a preload is applied. A ball bearing for a turning part of a main spindle body of a machine tool. A base, a spindle body spindle is mounted for rotating the tool is pivotable relative to the base platform, have a drive source for driving the main shaft body, said spindle body and the rotation axis of the spindle In a machine tool having a different rotation axis, a machine tool is provided between the base and the main spindle body, and a large number of balls are rotatably disposed between the outer raceway groove and the inner raceway groove. A ball bearing for the main spindle body swivel part,
The ball bearing has a double row ball bearing,
Is an axial cross-sectional width B 2 and the radial section sectional size ratio between the height H 2 (B2 / H2) is (B2 / H2) <1.2 for the ball bearing of the plurality rows,
In the ball bearing, either one of the outer ring and the inner ring is fastened and fixed to the base, and the other of the outer ring and the inner ring is fastened and fixed to the main spindle body, so that a preload is applied. A ball bearing for a turning part of a main spindle body of a machine tool.   3. The machine tool according to claim 1, wherein the ball bearing is disposed so that the main spindle body and the drive source are located on both sides of the ball bearing with respect to an axial direction of the ball bearing. Ball bearings for the main spindle body turning part.

Images