JP2006097872A - Bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing unit capable of not only receiving radial load, axial load in both directions and moment load, but also miniaturizing an axial space, reducing torque, improving rigidity, and being easily handled. <P>SOLUTION: In this bearing unit comprising a rolling bearing 100, a housing 18 for supporting an end part of a shaft 17 through the rolling bearing 100, and an outer ring pressor 15 for pressing and fixing the rolling bearing to the housing 18, the rolling bearing 100 is a single row ball bearing having a cross-sectional dimension ratio (B/H) of axial cross-sectional width B and radial cross-sectional height H satisfying (B/H)<0.63. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bearing unit used in, for example, industrial machines, robots, medical equipment, semiconductor / liquid crystal manufacturing apparatuses, optical and optoelectronic apparatuses, and the like.

A single roller bearing that can receive a radial load, an axial load in both directions, and a moment load includes a cross roller bearing (see, for example, Patent Document 1 and Patent Document 2), and a four-point contact ball bearing (for example, Patent Document 3 and Patent Document). 4) is known.
In the cross roller bearing, as shown in FIG. 30, a large number of cylindrical rollers 3 are rotatably arranged between the inner ring 1 and the outer ring 2, and the four-point contact ball bearing is as shown in FIG. In addition, a large number of balls 6 are arranged between the inner ring 4 and the outer ring 5 so as to freely roll. In addition, the combination of rolling bearings that can receive radial load, axial load in both directions, and moment load includes two-row combination deep groove ball bearings, or between inner ring 7 and outer ring 8 as shown in FIG. There are two-row combination angular contact ball bearings in which angular contact ball bearings in which a plurality of balls 9 are arranged so as to be able to roll (see, for example, Patent Document 5 and Patent Document 6).

However, in the case of a cross roller bearing, since the rolling element is a cylindrical roller 3 and the rolling contact surface of the roller 3 is in line contact with the raceway grooves 1a and 2a, the torque is large, and the shaft and Due to slight deformation when assembled in the housing, the contact state of the line contact portion becomes non-uniform and torque unevenness is likely to occur.
In a four-point contact ball bearing, since the rolling element is a ball 6, when receiving a pure axial load or when an axial load is dominant over a radial load, the torque is smaller than that of a cross roller bearing of the same size, but the radial load is smaller than the axial load. When the 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 the raceway grooves 4a and 5a is large and the torque is large.

  In addition, when using a cross roller bearing or a four-point contact ball bearing for the swivel joint of an arm-type robot, etc., in order to minimize the deflection of the arm tip due to an overhang load etc. when holding parts at the arm tip, Measures to increase the moment rigidity by applying preload to the bearings in advance are taken, but if preload is applied with these bearings, the torque will increase extremely, and the drive motor will have high horsepower and rotation failure including torque unevenness etc. The problem is likely to occur.

  In the case of a double row ball bearing, each single row bearing has a two-point contact between the balls and the raceway grooves of the inner and outer rings, so the torque can be reduced, but the axial width space is twice that of the single row bearing. Necessary and inferior to cross roller bearings and 4-point contact ball bearings in terms of compactness. In addition, standard angular contact ball bearings also have problems such as preventing grease from leaking to the outside and not having a seal to prevent foreign matter and dust from entering the bearing. As a result, the axial width increases.

FIG. 34 shows an example of a conventional bearing unit in which a two-row combination angular ball bearing is mounted on the end of the rotating shaft.
This bearing unit is combined in two rows to apply radial load, axial load in both directions, and moment load. The outer ring 8 and the inner ring 7 are respectively connected to a shaft 17 via an outer ring retainer 15, an inner ring spacer 16a and a bearing nut 16b. Although the seal is not attached to the bearing 18, it is necessary to attach an oil seal 19 for preventing foreign matter and oil from entering from the inside diameter of the housing 18 on both ends of the bearing. The axial space is quite long.

  Furthermore, there are two-row combination ball bearings that combine ultra-thin deep groove ball bearings and angular contact ball bearings (see FIG. 33) for the purpose of space saving. As an example, as shown in FIG. 7 and the outer ring 8 are fastened to the shaft 12 and the housing 13 with bolts 14 via the inner ring presser 10 and the outer ring presser 11, respectively. The outer ring presser 11 is a part of the outer diameter surface of the outer ring 8, and the inner ring presser 10 is a shaft. 12 is fitted to a part of the outer diameter surface of 12 and positioned so that the bearing and the core are not displaced via the shaft 12.

  Bearing units incorporating these ultra-thin two-row combination ball bearings are advantageous in terms of space saving, but the inner and outer rings 7, 8 have a very thin ring wall and the inner and outer rings 7, 8 have low rigidity. Therefore, there is a problem that machining accuracy is difficult to be obtained, and when incorporated in the shaft 12 or the housing 13, the inner ring presser 10 or the outer ring presser 11 is easily deformed by a pressing force, and it takes time to secure the assembly accuracy.

Further, depending on the case, the raceway grooves of the inner and outer rings 7 and 8 are distorted due to deformation at the time of incorporation, and an uneven load is applied between the contact portions between the balls 9 and the raceway grooves, or the smooth rolling motion of the balls 9 is hindered. Sometimes.
Japanese Utility Model Publication No. 1-444806 Japanese Unexamined Patent Publication No. 63-213457 Japanese Patent Laid-Open No. 11-62990 JP 2003-139145 A Japanese Utility Model Publication No. 5-66327 JP 2003-278765 A

  The present invention has been made to eliminate such inconveniences, and of course can receive a radial load, an axial load in both directions, and a moment load, and can save space and reduce torque in the axial direction. An object of the present invention is to provide a bearing unit that can achieve higher rigidity and can be easily assembled and simplified in design.

In order to achieve the above object, an invention according to claim 1 includes a rolling bearing, a housing that supports an end portion of the shaft via the rolling bearing, and an outer ring presser that presses and fixes the rolling bearing to the housing. A bearing unit comprising:
The rolling bearing is a single row ball bearing in which a sectional dimension ratio (B / H) between an axial sectional width B and a radial sectional height H is (B / H) <0.63. To do.

The invention according to claim 2 is a bearing unit comprising a rolling bearing, a housing that supports the end of the shaft via the rolling bearing, and an outer ring presser that presses and fixes the rolling bearing to the housing.
The rolling bearing is a double row ball bearing in which a cross-sectional dimension ratio (B2 / H2) between an axial cross-sectional width B2 and a radial cross-sectional height H2 is (B2 / H2) <1.2. To do.
The invention according to claim 3 is characterized in that, in claim 1 or 2, an annular seal body is provided at an axial end of at least one of the outer ring and the inner ring of the rolling bearing.

  In the invention according to claim 1, for example, with reference to FIGS. 4 and 22, the rolling bearing incorporated in the bearing unit has a large number of balls 103 between the raceway groove 101 a of the outer ring 101 and the raceway groove 102 a of the inner ring 102. This is a single-row ball bearing 100 that is arranged so as to be freely rollable, and has a cross-sectional dimension ratio of an axial cross-sectional width B and a radial cross-sectional height H (= (outer ring outer diameter D−inner ring inner diameter d) / 2) ( B / H) is (B / H) <0.63.

  Then, as shown in FIG. 5, the single row ball bearing 100 is inserted into the housing 18 as a two-row combination, and the inner ring 102 is fixed to the shaft 17 via the inner ring spacer 16a and the bearing nut 16b. 15 is inserted from the flange portion 18a side of the housing 18, the outer ring 101 is pressed and fixed in the axial direction, and an oil seal 19 for preventing foreign matter and oil from entering the housing 18 inner diameter portions on both ends of the bearing is provided. Wearing.

Here, standard ball bearings whose dimension series prescribed by the International Organization for Standardization (ISO) are 18 (for example, 6800), 19 (for example, 6901), 10 (for example, 6003), 02 (for example, 7205A), 03 (for example, 7307A) Then, when the bearing inner diameter is φ5 mm to φ100 mm, the above-mentioned cross-sectional dimension ratio (B / H) is set to 0.82 to 1.17.
Further, when the bearing inner diameter is φ5 mm to φ500 mm, the above-mentioned cross-sectional dimension ratio (B / H) is set to 0.63 to 1.17.

Therefore, the width of the conventional standard single-row ball bearing is the largest in width by setting it to about 1/2 times the maximum value 1.17 of the sectional dimension ratio (B / H) of these ball bearings, that is, less than 0.63. The ball bearings according to claim 1 can be arranged in combination of two rows within a narrower width than the narrow ball bearing and within the axial width space of the conventional standard single row ball bearing.
Moreover, 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 0.62 and the other may be 0.58. When both combined bearings have the same width, it is desirable that the cross-sectional dimension ratio (B / H) is 0.60 or less.

Here, FIG. 25 and FIG. 26 are each a standard thin ball bearing (bearing inner diameter: φ38.1 mm, bearing outer diameter: φ47.625 mm, bearing width: 4.762 mm, cross-sectional dimension ratio (B / H) = 1) as a reference, the radius of the inner and outer ring rings 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) direction of deformation characteristics (Figure 23 see the inner ring of illustration) and radial cross-sectional secondary moment I: shows the result of comparison (see FIG. 24 calculated as I = bh ^3/12).

  27 and 28 are also used as standard thin ball bearings (bearing inner diameter: φ63.5 mm, bearing outer diameter: φ76.2 mm, bearing width: 6.35 mm, cross-sectional dimension ratio (B / H) = 1) as a reference, the radius of the inner and outer ring rings 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) The result of having compared the deformation characteristic of a direction and the cross-sectional secondary moment I of the radial direction is shown.

In any of the bearings, (B / H) = 0.63, and the change in the rigidity increase rate gradient is noticeable. That is, the increase in the secondary moment I of the cross section becomes significant, and the decrease in the deformation amount of the inner and outer ring in the radial direction becomes saturated.
Therefore, in the invention according to claim 1, it is possible to prevent the bearing from being deformed due to the lathe machining during inner and outer ring production and the machining force during polishing, which is a problem with the conventional ultra-thin bearing, and the roundness, uneven thickness, etc. The bearing accuracy can be improved.

Deformation of inner and outer rings when bearings are fixed with inner ring retainers and outer ring retainers (especially when they are assembled with a clearance fit with the shaft or housing). In addition, it is possible to prevent torque defects and rotational accuracy defects caused by deformation, or problems such as increased heat generation, wear and seizure.
Single-row ball bearings are difficult to apply preload or moment load in one row, but by combining 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 ring raceway grooves at two points, an increase in torque due to a large spin of the ball such as a four-point contact ball bearing can be suppressed. Since the rolling resistance is lower than that, torque can be reduced.
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, but conversely, the number of balls per row is increased, and the bearing rigidity is conventional. Increased against ball bearings.

In addition, when applied to the arm joint of a turning robot, etc., low-speed oscillating rotation is almost the case, so even if the bearing load capacity is reduced by reducing the ball diameter, the rolling fatigue life time is practical. There is no problem.
Other industrial machines, robots, medical equipment, semiconductor / liquid crystal manufacturing equipment, optical and optoelectronic equipment, etc. have many applications with low rotational speed and rocking rotation, so rolling fatigue life time is rarely a problem. .
As described above, by using the narrow single-row ball bearing according to claim 1 and further forming a bearing unit together with parts such as a housing and an outer ring presser, space can be saved as compared with a conventional bearing unit. In addition, it is possible to facilitate the incorporation into a machine or the like and to simplify the design.

  When the invention according to claim 2 is described with reference to FIGS. 17 and 18, for example, the rolling bearing is provided 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. This is a double row ball bearing 200 in which a large number of balls 203 are arranged so as to be able to roll, and an axial sectional width B2 and a radial sectional height H2 (= (outer ring outer diameter D2-inner ring inner diameter d2) / 2) and The cross-sectional dimension ratio (B2 / H2) is (B2 / H2) <1.2.

  The double-row ball bearing 200 is inserted into the housing 18, the inner ring 202 is fixed to the shaft 17 via the inner ring spacer 16 a and the bearing nut 16 b, and the outer ring presser 15 is inserted from the flange portion 18 a side of the housing 18. Thus, the outer ring 201 is pressed and fixed in the axial direction, and an oil seal 19 is attached to the inner diameter portion of the housing 18 at both ends of the bearing to prevent entry of foreign matter and oil from the outside.

  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. The double-row ball bearing according to claim 2 can be disposed 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. 29 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), single row narrow angular balls according to claim 1 The 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 groove curvature of the inner and outer rings are changed are all cross roller bearings, standard double row angular contact balls The moment rigidity is higher than that of the bearing and the four-point contact ball bearing. For example, the present invention example B is 2.4 times that of the cross roller bearing, 1.9 times that of the conventional standard two-row combination angular ball bearing, 4 times It is possible to maintain a moment rigidity 3.3 times that of a point contact ball bearing.

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, which are standard in practical use. Calculated as a value.
In addition, the appropriate ball diameter of the narrow ball bearing used in the bearing unit of the present invention varies depending on whether or not a seal or the like is mounted. However, in order to increase rigidity, if the ball diameter is extremely reduced, the ball and the inner and outer rings Since the surface pressure between the contact portions with the raceway grooves increases and the pressure scar resistance may be lowered, generally 30 to 90% of the bearing width (B) or (B2 / 2) is desirable.

Furthermore, when applied to an angular ball bearing as a rolling bearing used in the bearing unit of the present invention, the contact angle of the bearing is selected depending on the required rigidity (for example, moment rigidity) and the required torque, but is generally 10 to 60 °. A range is desirable.
Furthermore, the contact angle of the combined bearings may be changed as necessary according to the direction and size of the load.
Furthermore, the radius of curvature of the raceway grooves of the inner and outer rings is 51 to 60% Da (Da: ball diameter), preferably 52 to 56% Da, more preferably 52 to 54, depending on required rigidity and torque characteristics. About% Da. Further, the radius of curvature of the raceway grooves of the inner and outer rings may not be the same, or may be different between the combined bearings or between the rows of the double row ball bearings.

  According to the present invention, when the rolling bearing incorporated in the bearing unit is a single row ball bearing, the sectional dimension ratio (B / H) between the axial sectional width B and the radial sectional height H is (B / H). ) <0.63, and in the case of a double row ball bearing, the sectional dimension ratio (B2 / H2) between the axial sectional width B2 and the radial sectional height H2 should be (B2 / H2) <1.2. Can receive radial load, axial load in both directions, and moment load, and can save space in the axial direction, reduce torque and increase rigidity, and simplify peripheral structure design. In addition, ease of incorporation can be achieved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially broken view for explaining a bearing unit as an example of an embodiment of the first aspect of the present invention, FIG. 2 is a left side view of FIG. 1, and FIG. 4 is a cross-sectional view of a main part for explaining a single row ball bearing incorporated in the bearing unit of FIG. 1, FIGS. 5 to 16 are views showing modifications of the single row ball bearing, and FIG. FIG. 18 is a partially broken view for explaining a bearing unit which is an example of an embodiment of the embodiment of FIG. 2, FIG. 18 is a cross-sectional view of the main part of a double row ball bearing incorporated in the bearing unit of FIG. 21 is a sectional view of an essential part for explaining a modification of the double row ball bearing.

  As shown in FIGS. 1 and 4, the bearing unit 20, which is an example of an embodiment of the first aspect of the present invention, has a rolling bearing between the raceway groove 101 a of the outer ring 101 and the raceway groove 102 a of the inner ring 102. A single row of angular contact ball bearings 100, in which a large number of balls 103 are rotatably arranged, have an axial sectional width B and a radial sectional height H (= (outer ring outer diameter D−inner ring inner diameter d). ) / 2) and the cross-sectional dimension ratio (B / H) is (B / H) <0.63.

  Then, as shown in FIGS. 1 and 5, the single row ball bearing 100 is inserted into the housing 18 as a two-row front combination (contact angle is a reverse C shape), and the inner ring 102 is inserted into the inner ring spacer 16a and the bearing nut. The outer ring retainer 15 is inserted from the flange portion 18a side of the housing 18 and is fixed by pressing the outer ring 101 in the axial direction. And an oil seal 19 for preventing intrusion of oil.

Further, the flange portion 18 a of the housing 18 is fixed to the machine base 24 or the like by bolts 21, and the flange portion 15 a of the outer ring retainer 15 is fixed to the flange portion 18 a of the housing 18 by bolts 23. 1 and 2, reference numeral 22 denotes an insertion hole provided in the flange portion 15 a of the outer ring presser 15 for inserting the head of the bolt 21.
Further, in this embodiment, a clearance Δa is provided in advance between the adjacent outer rings 101, and the gap between the flange portion 18a of the housing 18 and the flange portion 15a of the outer ring retainer 15 is too appropriate ΔS (ΔS> Δa). ) Is provided.

Then, by tightening the bolt 23 until the clearance Δa disappears, an appropriate preload is applied to the bearing, and low vibration and high rotation accuracy can be ensured. The increase / decrease of the preload amount can be adjusted by the magnitude of the clearance Δa.
In the case where high rigidity is not required, a bearing having a clearance set without applying preload may be used. Further, the shape of the flange portion 18a of the housing 18 is not particularly limited, and for example, a square shape as shown in FIG. Furthermore, in the case where an annular seal body is used for the bearing or in the case where there is little invasion of foreign matter or oil from the outside, one or both of the oil seals 19 attached to both ends of the bearing are removed. It doesn't matter. In this case, the axial space of the bearing unit can be further shortened.

Here, in this embodiment, a case where the angular ball bearing 100 is a two-row front combination and replaced with a double-row angular contact ball bearing of 7208A (contact angle 30 °) shown in FIG. 34 is taken as an example.
The 7208A angular contact ball bearing has an inner ring inner diameter φ40 mm, an outer ring outer diameter φ80 mm, and an axial sectional width (bearing single body width) B of 18 mm, so the sectional dimension ratio (B / H) = 0.9. Therefore, in the angular ball bearing 100 of the present embodiment, the sectional dimension ratio (B / H) = 0.45 (the inner ring inner diameter and the outer ring outer diameter remain the same, and the axial sectional width (bearing single body width) is 9 mm). Yes.

As a result, radial load, axial load in both directions, and moment load can be received, as well as 1/2 space saving in axial dimension, lower torque, and higher rigidity can be achieved. Furthermore, it is possible to simplify the peripheral structure design and facilitate the incorporation.
Of course, as necessary, as a rolling bearing used in the bearing unit, the cross-sectional dimension ratio (B / H) of the angular ball bearing 100 is less than 0.45 or more than 0.45 (provided that (B / H) <0. 63) It may be set as follows. 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 formula (1). However, when it is desired to increase the moment rigidity by increasing the number of balls per row of the bearing, the following formula (2) is used. The pitch circle diameter of the ball 103 may be shifted to the outer ring side and the structure shown in FIG. 6 may be adopted, or the following equation (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)

  If necessary, as shown in FIG. 7, the ball pitch circle diameters of the left and right ball bearings to be combined may not be the same value, and the diameters of the balls 103 of the left and right ball bearings to be combined should be 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) = 0.28, and the larger ball diameter is (B / H). ) = 0.62. Further, the axial pitch of the balls 103 may not be the center of 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 application points of the moment and the moment of attachment of the seal and the cage. Good.

FIG. 8 shows a two-row front combination of angular ball bearings 100 having an annular seal body 104 mounted at 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 attached to a machine or the like (combined with the seal mounting surface facing outward), the external ball bearing 100 is used while the bearing is in use. 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. 9 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 with 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 and 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.

When further rigidity is required, as shown in FIGS. 10 and 11, a rolling bearing used for the bearing unit may be a multi-row combination of three or more rows.
Furthermore, in order to apply 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 rolling bearing used in the bearing unit is an angular ball bearing, 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. 8 and 9, but may be a contact type metal core reinforced rubber seal (the rubber material is, for example, nitrile rubber, acrylic rubber or fluororubber), 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 inserted 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 use conditions, but depending on the use environment, for example, a stainless steel that is a corrosion-resistant material in vacuum applications. Materials (for example, martensitic stainless steel materials such as SUS440C, austenitic stainless steel materials such as SUS304, precipitation hardening stainless steel materials such as SUS630), titanium alloys and ceramic materials (for example, Si ₃ N ₄ , SiC, Al ₂₎ O ₃ , ZrO _2, etc.) may be employed.
The lubrication method is not particularly limited, and mineral oil grease or synthetic oil grease (for example, lithium or urea) or oil can be used in general usage environments, and fluorine grease or fluorine grease for vacuum applications. Or a solid lubricant such as fluorine resin or 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 two-row front combination.
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. Further, the pitch in the axial direction of the balls 103 is shifted as much as possible to the opposite side of the end face on the combination side (FIG. 12: X ₁ > X ₂ ), and the ring portion 111 of the cage 110 is arranged so as to be on the end face side of the bearing combination. .
In the case of a full ball bearing, the axial pitch of the balls is not the center of the width in the same way as necessary, such as whether or not an annular seal body is mounted. 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.
Further, as in this embodiment, if the entrance portion of the pocket portion 113 is slightly smaller than the diameter of the ball and is provided with a catch (pachin allowance), the ball 103 will not drop off when assembled into the inner ring 102 and the outer ring 101. Easy to assemble.

The shape of the cage is not limited to this embodiment, and any system 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 rolling element pitch circle diameter deviates from the pocket pitch circle diameter of the cage due to differences in the thermal expansion coefficient between the cage and the inner and outer rings and variations in the dimensional accuracy and roundness of the cage. Even in this case, the ball 103 has both the flexibility in the radial direction due to the cantilever shape and the elastic deformation in the circumferential direction (the flexibility in the circumferential direction) due to the gaps between the cut surfaces. The tension force between the pocket portions 113 can be buffered to prevent the cage from being damaged or worn, and the torque unevenness and heat generation due to the sliding contact resistance between the balls 103 and the inner surfaces of the pocket portions 113 can be further reduced.

  In addition, since the ball bearing of the present invention has a structurally small ball diameter, the radial direction thickness of the annular portion 111 of the cage cannot be increased (as can be understood from FIG. 12, the cage is an inner ring). It is necessary to position the gap between the outer diameter and the inner diameter of the outer ring by providing an appropriate gap, and the gap between the outer diameter of the inner ring and the inner diameter of the outer ring is substantially proportional to the ball diameter and is narrow) Furthermore, due to the narrow structure, the gap in the axial direction is narrow and the axial thickness is inevitably 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 above-described cage damage and wear prevention effect and torque unevenness and heat generation reduction effect can be obtained.
Also, the intended application is when the dmn value of the bearing (dm: product of rolling element pitch circle diameter (mm) of rolling bearing and n: rotational speed (min ^-1 )) is 200,000 to 300,000 or less at most In many cases, when the present invention is applied to these uses, even if the cage structure 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.

Next, with reference to FIG.17 and FIG.18, the bearing unit which is an example of embodiment of the 2nd aspect of this invention is demonstrated.
As shown in FIGS. 17 and 18, the bearing unit 30, which is an example of an embodiment of the second aspect of the present invention, has rolling bearings with double row raceway grooves 201 a and 201 b of the outer ring 201 and double rows of the inner ring 202. A double row full ball angular contact ball bearing 200 in which a large number of balls 203 are movably disposed between the raceway grooves 202a and 202b is provided. The axial sectional width B2 and the radial sectional height H2 (= ( The cross-sectional dimension ratio (B2 / H2) to the outer ring outer diameter D2—the inner ring inner diameter d2) / 2) is set to (B2 / H2) <1.2, and the ball pitch circle diameter is set at the center of the radial cross-sectional height. ing.

  The double-row ball bearing 200 is inserted into the housing 18, the inner ring 202 is fixed to the shaft 17 via the inner ring spacer 16 a and the bearing nut 16 b, and the outer ring presser 15 is inserted from the flange portion 18 a side of the housing 18. Thus, the outer ring 201 is pressed and fixed in the axial direction, and an oil seal 19 is attached to the inner diameter portion of the housing 18 at both ends of the bearing to prevent entry of foreign matter and oil from the outside.

Further, an appropriate gap (not shown) is provided between the flange portion 18a of the housing 18 and the flange portion 15a of the outer ring retainer 15, and the bearing is deformed by tightening the bolt 23 with an appropriate torque. It is fixed without. Note that a preload may be set for the bearing in advance, or a clearance may be set.
Here, in this embodiment, the double-row ball bearing 200 is replaced with a double-row combination angular ball bearing of 7208A (contact angle 30 °).

  7208A has an inner ring inner diameter φ40 mm, an outer ring outer diameter φ80 mm, and an axial cross-sectional width (bearing single body width): B is 18 mm, so the cross-sectional dimension ratio (B / H) = 0.9. Therefore, in the angular ball bearing 200 used for the bearing unit 30 of the present embodiment, the cross-sectional dimension ratio (B2 / H2) = 0.90 (the inner ring outer diameter and the outer ring outer diameter remain the same, and the axial sectional width (the bearing unit) Width): B2 is 18 mm).

As a result, radial load, axial load in both directions, and moment load can be received, as well as 1/2 space saving in axial dimension, lower torque, and higher rigidity can be achieved. Furthermore, it is possible to simplify the peripheral structure design and facilitate the incorporation.
Of course, if necessary, the cross-sectional dimension ratio (B2 / H2) may be set to be less than 0.90 or more than 0.90 (however, (B2 / H2) <1.2). Incidentally, the contact angle of the angular ball bearing 200 is, for example, 30 °.

FIG. 19 shows 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. 20 shows each row in the double row full ball angular contact ball bearing 200. FIG. 21 shows an example in which the ball diameter and the ball pitch circle diameter are changed. FIG. 21 shows a ball pitch circle in order to increase the moment rigidity in the double-row all-ball angular ball bearing 200 in which the annular seal bodies 104 are mounted at both ends in the axial direction. This is an example in which the diameter is shifted to the outer diameter side.
In any case of the embodiment of the second aspect, in addition to the structure of the annular seal body, the cage, etc. and whether or not it is mounted, application examples relating to the structure, bearing material, lubrication method, etc. According to the single row ball bearing described in the embodiment of the aspect.

It is the figure which fractured | ruptured one part for demonstrating the bearing unit which is an example of embodiment of the 1st aspect of this invention. It is a left view of FIG. It is a modification of a flange part. It is principal part sectional drawing for demonstrating the single row ball bearing integrated in the bearing unit of FIG. It is principal part sectional drawing which shows the state which combined the single row ball bearing of FIG. 4 with 2 rows. It is principal part sectional drawing which shows the state which combined the 2nd modification of the single row ball bearing. It is principal part sectional drawing which shows the state which combined the modification of the single row ball bearing, and the single row ball bearing of FIG. It is principal part sectional drawing which shows the state which combined the 2nd modification of the single row ball bearing. It is principal part sectional drawing for demonstrating the modification of a single row ball bearing. It is principal part sectional drawing which shows the state which combined the single row ball bearing of FIG. 4 with 3 rows. It is principal part sectional drawing which shows the state which combined the single row ball bearing of FIG. 4 with 4 rows. It is principal part sectional drawing which shows the state which combined the 2nd modification of the single row ball bearing. 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 the figure which fractured | ruptured part for demonstrating the bearing unit which is an example of embodiment of the 2nd aspect of this invention. It is principal part sectional drawing of the double row ball bearing integrated in the bearing unit of FIG. It is principal part sectional drawing for demonstrating the modification of a double row ball bearing. It is principal part sectional drawing for demonstrating the modification of a double row ball bearing. It is principal part sectional drawing for demonstrating the modification of a double row ball bearing. It is the figure which fractured | ruptured one part for demonstrating the bearing unit of the invention which concerns on Claim 1. FIG. 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 a 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 relationship between a cross-sectional dimension ratio (B / H) and the deformation amount of the inner and outer ring | wheels of a 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 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 the figure which fractured | ruptured one part for demonstrating the conventional bearing unit. 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.

Explanation of symbols

15 Outer ring presser 17 Shaft 18 Housing 20, 30 Bearing unit 100 Single row ball bearing (rolling bearing)
101 outer ring 102 inner ring 104 annular seal body 200 double row ball bearing (rolling bearing)
201 outer ring 202 inner ring

Claims (3)

A bearing unit comprising: a rolling bearing; a housing that supports an end of the shaft via the rolling bearing; and an outer ring presser that presses and fixes the rolling bearing to the housing.
The rolling bearing is a single row ball bearing in which a sectional dimension ratio (B / H) between an axial sectional width B and a radial sectional height H is (B / H) <0.63. Bearing unit. A bearing unit comprising: a rolling bearing; a housing that supports an end of the shaft via the rolling bearing; and an outer ring presser that presses and fixes the rolling bearing to the housing.
The rolling bearing is a double row ball bearing in which a cross-sectional dimension ratio (B2 / H2) between an axial cross-sectional width B2 and a radial cross-sectional height H2 is (B2 / H2) <1.2. Bearing unit.   The bearing unit according to claim 1, wherein an annular seal body is provided at at least one axial end of the outer ring and the inner ring of the rolling bearing.

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