JP2001330037A - Cylindrical roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the retaining performance of grease contributing to the lubrication of the inner surfaces of a bearing. SOLUTION: A pair of tandem retainers 4 are assembled in such an attitude that an annular part 4a is faced downward and a column part 4b is faced upward to hold rollers 3 at each row. When an inner ring 1 is rotated about a vertical axis X together with a spindle, grease G inside a bearing is allowed to flow upward by the protruding action of each retainer 4, and the amount of grease on the upper end B side and the lower side C1 at the center part C is increased and the amount of grease on the lower end A side and the upper side C2 at the center part C is reduced. The grease accumulated on the upper end B side and the lower side C1 and upper side C2 at the center part C is allowed to gradually flow down by the effect of the gravity to contribute to the lubrication of the rollers 3 at each row.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical roller bearing used for supporting a machine tool main shaft and the like.

[0002]

2. Description of the Related Art In a machine tool such as a machining center, a CNC lathe, and a milling machine, a main shaft is rotatably supported by a housing with a bearing. The main shaft has a vertical axis (the axis X is oriented in the vertical direction) and a horizontal axis (the axis X is oriented in the horizontal direction) depending on the machine type. In addition, grease lubrication or oil lubrication is adopted as a bearing lubrication method according to the use conditions and the like.

FIG. 10 shows a conventional double-row cylindrical roller bearing used for supporting a main shaft of a machine tool. Double row roller 1 between inner ring 15 of double row track and outer ring 16 of double row track
7 are interposed and are rotatably held by a pair of holders 18. The inner race 15 is fitted around the outer periphery of a main shaft (vertical axis: not shown) rotating around a vertical axis X, and
Is fitted on the inner periphery of a housing (not shown). Each of the pair of retainers 18 is a comb-shaped retainer formed of a metal material such as a high-strength brass casting (a so-called “comb retainer”).
An annular portion 18a, a plurality of pillar portions 18b extending from the annular portion 18a on both sides in the axial direction, and pillar portions 18b circumferentially adjacent to each other.
And a pocket 18c formed therebetween. The upper retainer 18 holds the rollers 17 with the annular portion 18a on the lower side and the column portion 18b on the upper side, and the lower retainer 18 has the annular portion 18a on the upper side and the column portion 18b on the lower side. Roller 1 with posture
Hold 7.

[0004]

Generally, a comb-shaped retainer has an action of pushing grease in a pocket from a ring-shaped portion toward a tip end of a pillar portion with rotation due to its shape characteristics. Therefore, when the conventional cylindrical roller bearing shown in FIG. 10 is operated with grease lubrication, grease G in the bearing is discharged to both ends A and B by the pushing action of the retainer 18, and depending on the use conditions, lubrication may be insufficient. May fall. In particular, when a conventional cylindrical roller bearing is used for supporting the longitudinal axis, the grease G in the bearing is discharged to the lower end portion A side largely due to the influence of gravity (the grease discharged to the lower end portion A side is Does not contribute to the lubrication of the bearing), and the amount of grease on the upper end portion B side and the central portion C side which contributes to the lubrication inside the bearing is reduced, and problems such as insufficient lubrication and an increase in bearing temperature are likely to occur. On the other hand, if the amount of grease on the upper end B side and the center C side contributing to lubrication in the bearing is to be maintained at an appropriate amount, the initial filling of grease including the amount of grease discharged to the lower end A in the initial operation is performed. You need to set the amount. Therefore, the amount of grease initially charged increases, which leads to an increase in bearing temperature due to the stirring resistance of the grease.

In this type of bearing, the width W1 of both ends A and B and the width W2 of the center C are usually (W2
/ 2) <W1. Therefore, in the configuration in which the annular portions 18a of the pair of retainers 18 are arranged in abutting manner at the central portion C, it is necessary to limit the width dimension of the annular portions 18a to less than (W2 / 2). In such a case, it is expected that the rigidity of the annular portion is insufficient depending on the use conditions.

[0006] It is an object of the present invention to improve the retention of grease contributing to lubrication in a bearing and to reduce the initial amount of grease to be filled, whereby the lack of lubrication in this kind of cylindrical roller bearing is achieved. An object of the present invention is to solve the problem and to suppress a rise in bearing temperature.

Another object of the present invention is to make it possible to increase the rigidity of the annular portion in the resin cage,
An object of the present invention is to cope with a further increase in speed by suppressing deformation of the cage during high-speed rotation.

[0008]

To achieve the above object, the present invention provides an inner ring, an outer ring, a plurality of rollers interposed between the inner ring and the outer ring, and a resin retainer for holding the rollers. A cylindrical roller bearing having an axial line oriented in the vertical direction, wherein the retainer has an annular portion, a plurality of pillar portions extending in one of the axial directions from the annular portion, and circumferentially adjacent to each other. Having a pocket formed between the pillars, and the annular portion on the lower side,
Provided is a configuration in which rollers are held in a posture in which a pillar portion faces upward. This configuration includes a single-row cylindrical roller bearing having a single-row track and row, a double-row cylindrical roller bearing having a double-row track and row, and a multi-row cylindrical roller having a multi-row (three or more) track and row. Bearings are included. In the case of a single row cylindrical roller bearing, a plurality of bearings may be arranged adjacent to each other in the axial direction. In either case,
The rollers in each row are individually held by the retainers, and the posture of each retainer is such that the annular portion is on the lower side and the pillar portion is on the upper side.

Further, the present invention provides an inner ring of a double-row track, an outer ring of a double-row track, double-row rollers interposed between the inner and outer rings, and a pair of resin-made holding rollers of each row. A cylindrical roller bearing having an axis oriented in the horizontal direction, wherein each of the pair of retainers has an annular portion, and a plurality of pillar portions extending from the annular portion in one of the axial directions. And a pocket formed between the pillars adjacent to each other in the circumferential direction, and the rollers of each row are held in a posture in which the annular portion is on the outside and the pillar is on the inside.

The cylindrical roller bearing of the present invention produces favorable results when operated with grease lubrication, and is particularly suitable as a main shaft bearing for machine tools.

According to another aspect of the present invention, there is provided a machine tool main spindle which is inserted into a housing and rotatably supports a main spindle rotating about a vertical axis with a plurality of rolling bearings relative to the housing. A support structure, wherein at least one rolling bearing includes an inner ring having a double-row track, an outer ring having a double-row track, a double-row roller interposed between the inner ring and the outer ring, and a roller in each row. A pair of resin retainers for holding, the pair of retainers respectively having an annular portion, a plurality of column portions extending in one axial direction from the annular portion, and a column portion adjacent in the circumferential direction. The cylindrical roller bearing has a pocket formed in the cylindrical roller bearing and holds the rollers in each row in a posture in which the annular portion is on the lower side and the column portion is on the upper side.

[0012] The present invention is also provided,
A main shaft rotating about a horizontal axis, a support structure of a machine tool main shaft rotatably supported by a plurality of rolling bearings with respect to the housing, at least one rolling bearing, an inner ring having a double row track, An outer ring having a double-row raceway, a double-row roller interposed between the inner ring and the outer ring, and a pair of resin-made retainers respectively holding the rollers of each row, a pair of retainers, An annular portion, a plurality of pillars extending in one axial direction from the annular portion, and a pocket formed between the pillars adjacent in the circumferential direction, and the annular portion is outside, and the pillar is inside. The present invention provides a structure that is a cylindrical roller bearing that holds the rollers in each row in an inclined position.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a machining center, a CNC lathe,
2 shows a support structure of a main spindle in a machine tool such as a milling machine. In this embodiment, the main shaft 10 rotates at high speed about a vertical axis X (vertical axis), and a double-row cylindrical roller bearing 12, a combined angular ball bearing (a pair of angular ball bearings) 13 and a single It is rotatably supported by a row cylindrical roller bearing 14.

FIG. 2 shows a double-row cylindrical roller bearing 1 shown in FIG.
2 is enlarged. The cylindrical roller bearing 12 includes an inner ring 1 having a double row track, an outer ring 2 having a double row track,
The vehicle includes a plurality of rows of rollers 3 interposed between the inner ring 1 and the outer ring 2, and a pair of resin retainers 4 for holding the respective rows of rollers 3. The inner race 1 is fitted on the outer periphery of the main shaft (10), and the outer race 2 is fitted on the inner periphery of the housing (11).
In this embodiment, the inner ring 1 has a tapered inner diameter surface 1a.
The inner diameter surface 1a is taperedly fitted to the tapered outer peripheral surface of the main shaft (10). Each retainer 4 is made of polyamide,
An annular portion 4a, a plurality of pillars 4b extending in one axial direction from the annular portion 4a, and pillars adjacent in the circumferential direction, which are formed of a resin material such as PPS (for example, formed by injection molding). There is a pocket 4c formed between 4b. The rollers 3 in each row are rotatably accommodated in pockets 4c of the retainers 4, respectively. Grease is sealed in the bearing (applied to the raceway surface, the rollers and the surface of the cage).

As shown in FIG. 3 to FIG.
Inner end surface 4a1 of the annular portion 4a (wall surface on the pocket 4c side)
Is provided with a contact surface 4a2 that comes into contact with the end surface 3a of the roller 3. The contact surface 4a2 is provided in a partial area of the inner end surface 4a1, and protrudes from the inner end surface 4a1 toward the pocket 4c in a stepped manner. In this embodiment, the contact surface 4a
Reference numeral 2 is provided in a region on the inner diameter side of the inner end face 4a1 and on the center side in the circumferential direction. Contact surface 4a of inner end surface 4a1
When only 2 comes into contact with the end face 3a of the roller 3, the sliding friction of the contact portion between them is reduced. Also, the inner end face 4a
A small space is formed between the area excluding the contact surface 4a2 (the area on the outer diameter side and both sides in the circumferential direction) and the end face 3a of the roller 3, and this serves as a grease reservoir, so that the roller 3 Lubrication at the end face 3a of the substrate is promoted.

An engagement portion 4b1 is provided on the inner diameter side of the pillar portion 4b of the retainer 4 so as to project more inwardly than the inner diameter surface of the annular portion 4a. When the retainer 4 is incorporated in the bearing, the engaging portion 4b1 comes into contact with the flange surface of the inner ring 1 so that the retainer 4 can be removed in the axial direction (downward in FIGS. 1 and 2). Is prevented. In FIG. 4, the circumferential dimension between the column portions 4 b adjacent in the circumferential direction is smallest on the outer diameter side, and the minimum dimension W is smaller than the diameter D of the roller 3. Therefore, when the roller 3 accommodated in the pocket 4c relatively moves to the outer diameter side with respect to the retainer 4, the roller 3 engages with the outer diameter side portion of the pillar portion 4b, whereby the roller 3 is prevented from falling off to the outer diameter side. Is prevented.

As shown in FIG. 2, each of the retainers 4 is assembled with the annular portion 4a on the lower side and the column portion 4b on the upper side to hold the rollers 3 in each row. When the inner ring 1 rotates around the vertical axis X together with the main shaft (10), the grease G in the bearing flows upward by the pushing action of each retainer 4, and the upper end B side (the upper roller row). Upper end side), lower part C1 of central part C (upper end side of lower roller row)
And the amount of grease on the lower end portion A side (the lower end surface side of the lower roller row) and the upper portion C2 of the central portion C (the lower end surface side of the lower roller row) are reduced. Upper end B side, central part C
The grease accumulated on the lower side C1 and the upper side C2 gradually flows down under the influence of gravity and contributes to the lubrication of the rollers 3 in each row. Therefore, in the cylindrical roller bearing of this embodiment, insufficient lubrication is unlikely to occur, and a stable operating state can be maintained for a long period of time. Further, the lower end portion A which does not contribute to lubrication in the bearing.
Since the amount of grease on the side is reduced, the amount of grease initially charged can be reduced as compared with the conventional case, whereby the stirring resistance of the grease can be reduced and the bearing temperature rise can be suppressed.

Since the width of the annular portion 4a of the retainer 4 is not restricted as in the conventional bearing shown in FIG. 10, the width of the annular portion 4a should be (W2 / 2) or more, preferably (W2 / 2). / 2) and increase to W1 or less to reduce the annular portion 4
It is possible to increase the rigidity of a. Thereby, deformation of the retainer 4 during high-speed rotation can be suppressed, and it is possible to cope with a further increase in the speed of main shaft rotation. In addition, W1 is both ends A,
The width dimension of B and W2 is the width dimension of the central portion C (see FIG. 10).

The embodiment shown in FIG.
a is a cylindrical surface parallel to the axis X. Inner ring 1
Is fitted to the cylindrical outer peripheral surface of the main shaft.
Other items are the same as those in the above-described embodiment, and a duplicate description will be omitted.

FIG. 7 shows a single-row cylindrical roller bearing 1 shown in FIG.
4 is enlarged. The cylindrical roller bearing 14 includes an inner ring 21 having a single-row track and an outer ring 22 having a single-row track.
And a single row roller 2 interposed between the inner race 21 and the outer race 22
3 and a resin holder 24 for holding the rollers 23. The inner race 21 is fitted on the outer periphery of the main shaft (10), and the outer race 22 is fitted on the inner periphery of the housing (11). In this embodiment, the inner race 21 has a tapered inner diameter surface 21a.
The inner diameter surface 21a is taperedly fitted to the tapered outer peripheral surface of the main shaft (10). The retainer 24 is formed of a resin material such as polyamide or PPS (for example, formed by injection molding), and has an annular portion 24a, a plurality of column portions 24b extending in the axial direction from the annular portion 24a, and a circle. A pocket 24c is formed between the pillars 24b adjacent in the circumferential direction. Rollers 23 are pockets 24c of cage 24.
Are respectively rotatably accommodated. Grease is sealed in the bearing (applied to the raceway surface, the rollers and the surface of the cage).

The retainer 24 is installed with the annular portion 24a on the lower side and the column portion 24b on the upper side to hold the rollers 23. When the inner ring 21 rotates around the vertical axis X together with the main shaft (10), the grease G in the bearing is transferred to the cage 24.
Of the grease at the upper end portion B side, and the grease amount at the lower end portion A side decreases. The grease accumulated on the upper end B side gradually flows down under the influence of gravity and contributes to the lubrication of the rollers 23. Therefore, in the cylindrical roller bearing of this embodiment, insufficient lubrication is unlikely to occur, and a stable operating state can be maintained for a long period of time. In addition, the amount of grease on the lower end portion A side that does not contribute to lubrication in the bearing is reduced, so that the initial amount of grease can be reduced as compared with the conventional case, thereby reducing the stirring resistance of the grease and increasing the bearing temperature. Can be suppressed. Other items are the same as those in the above-described embodiment, and a duplicate description will be omitted.

FIG. 8 shows another embodiment of a main shaft support structure in a machine tool. In this embodiment,
The main shaft 10 'rotates at a high speed about a horizontal axis X (horizontal axis), and the double row cylindrical roller bearing 12
, Are rotatably supported by a combination angular contact ball bearing (a pair of angular contact ball bearings) 13 'and a single-row cylindrical roller bearing 14'.

FIG. 9 shows a double-row cylindrical roller bearing 1 shown in FIG.
2 'is shown enlarged. When the main shaft (10 ') that rotates around the horizontal axis X is rotatably supported with respect to the housing (11') as in this embodiment, each of the retainers 4 is attached to the annular portion 4a. It is incorporated in a posture in which the outside (the outside of the bearing) and the column portion 4b are inside (the inside of the bearing). The inner ring 1 has a horizontal axis X along with the main shaft (10 ').
When the grease G rotates around, the grease G in the bearing flows toward the inside of the bearing due to the pushing action of each cage 4, so that the amount of grease at the central portion C is large, and the amount of grease at both ends A and B is small. Since the grease accumulated on the central portion C side contributes to lubrication of the rollers 3 in each row, insufficient lubrication hardly occurs, and a stable operation state can be maintained for a long period of time.
In addition, the amount of grease at both ends A and B that do not contribute to lubrication in the bearing is reduced, so that the initial amount of grease can be reduced as compared with the conventional case. Temperature rise can be suppressed. Other items are the same as those in the above-described embodiment, and a duplicate description will be omitted.

[0025]

The cylindrical roller bearing of the present invention has a high retention of grease contributing to lubrication in the bearing and is unlikely to cause insufficient lubrication, so that a stable operating state can be maintained for a long period of time. In addition, since the initial amount of grease can be made smaller than before, the stirring resistance of the grease is reduced, and the rise in bearing temperature is suppressed. Furthermore, by increasing the width of the annular portion of the cage, it is possible to increase the rigidity of the annular portion, thereby suppressing deformation of the cage during high-speed rotation and responding to higher speed spindle rotation. can do.

The support structure for a machine tool spindle according to the present invention has a small bearing temperature rise and is excellent in high-speed rotation.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a spindle support structure of a machine tool according to an embodiment.

FIG. 2 is an enlarged sectional view of the double-row cylindrical roller bearing in FIG.

FIG. 3 is a longitudinal sectional view of the retainer.

FIG. 4 is a front view of the retainer (a view as viewed from the front end side of the pillar).

FIG. 5 is a plan view (a view as viewed from the outside diameter side) of the cage.

FIG. 6 is a sectional view of a double-row cylindrical roller bearing according to another embodiment.

FIG. 7 is a sectional view of the single-row cylindrical roller bearing in FIG. 1;

FIG. 8 is a cross-sectional view illustrating a spindle support structure of a machine tool according to another embodiment.

9 is an enlarged sectional view of the double row cylindrical roller bearing in FIG.

FIG. 10 is a sectional view showing a conventional double-row cylindrical roller bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Roller 4 Cage 4a Annular part 4b Column part 4c Pocket 10 Main shaft 11 Housing X axis

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi TAKO Municipal Kuwana-shi Mie Prefecture Ogata Oyumida 3066 Inside NTN Co., Ltd. F term in the company (reference) 3J101 AA13 AA42 AA43 AA52 AA62 BA25 CA13 GA31

Claims (8)

[Claims] 1. A cylindrical roller having an inner ring, an outer ring, a plurality of rollers interposed between the inner ring and the outer ring, and a resin retainer for holding the rollers, the cylindrical rollers being arranged with their axes directed vertically. A bearing, wherein the retainer has an annular portion, a plurality of pillar portions extending in one axial direction from the annular portion, and a pocket formed between circumferentially adjacent pillar portions, and A cylindrical roller bearing, wherein the rollers are held in a posture in which the annular portion is on the lower side and the column portion is on the upper side. 2. The inner ring has a double-row raceway, the outer race has a double-row raceway, and double-row rollers are interposed between the inner race and the outer race to hold the rollers in each row. 2. The cylindrical roller bearing according to claim 1, wherein the pair of retainers respectively hold the rollers in each row in a posture in which the annular portion is on the lower side and the pillar portion is on the upper side. 3. Characteristic cylindrical roller bearing. 3. An inner ring of a double-row track, an outer ring of a double-row track,
A cylindrical roller bearing comprising a double row of rollers interposed between an inner ring and an outer ring, and a pair of resin cages respectively holding the rollers of each row, wherein an axial line is arranged in a horizontal direction. The pair of retainers each include an annular portion, a plurality of pillars extending in the axial direction from the annular portion, and a pocket formed between pillars adjacent in the circumferential direction, and A cylindrical roller bearing, wherein the rollers in each row are held in a posture in which the annular portion is on the outside and the column portion is on the inside. 4. The cylindrical roller bearing according to claim 1, which is operated with grease lubrication. 5. The cylindrical roller bearing according to claim 1, which is used for supporting a main shaft of a machine tool. 6. A support structure for a machine tool spindle, wherein the spindle inserted into the housing and rotated about a vertical axis is rotatably supported on the housing by a plurality of rolling bearings, wherein at least one of the rolling elements is provided. Bearing, an inner ring having a double-row raceway, an outer ring having a double-row raceway, double-row rollers interposed between the inner ring and the outer ring, and a pair of resin cages respectively holding the rollers of each row. The pair of retainers each have an annular portion, a plurality of pillar portions extending in the axial direction from the annular portion, and pockets formed between circumferentially adjacent pillar portions. And a cylindrical roller bearing for holding the rollers in each row with the annular portion facing downward and the column facing upward. 7. A support structure for a machine tool spindle, wherein the spindle inserted into the housing and rotated about a horizontal axis is rotatably supported with respect to the housing by a plurality of rolling bearings, wherein at least one of the rolling elements is provided. Bearing, an inner ring having a double-row raceway, an outer ring having a double-row raceway, double-row rollers interposed between the inner ring and the outer ring, and a pair of resin cages respectively holding the rollers of each row. The pair of retainers each have an annular portion, a plurality of pillar portions extending in the axial direction from the annular portion, and pockets formed between circumferentially adjacent pillar portions. And a cylindrical roller bearing for holding the rollers in each row with the annular portion on the outside and the pillars on the inside. 8. The support structure for a machine tool spindle according to claim 6, wherein said cylindrical roller bearing is operated by grease lubrication.