JP2002130261A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing capable of receiving radial load, axial load in both directions, and moment load and satisfying high moment rigidity. SOLUTION: The rolling bearing is comprised of an outer ring and inner ring respectively, having a raceway groove consisted of two raceway surfaces that have a radius greater than the radius of a rolling body, and a plurality of the rolling body, in which the outer diameter to be turned to a rolling contact face is given a curvature in the axial direction. The rolling bodies are alternately assembled in a crossed state, and the outer diameter of each rolling body is also brought into contact with one of the raceway surfaces of the outer ring and one of the raceway surfaces of the inner ring always facing each other in a two-point contact state. The rolling bearing has both a low torque for a four-point contact ball bearing and high moment rigidity of a crossed roller bearing, by setting negative the bearing with the internal clearance in a pre-loaded state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing capable of receiving a radial load, an axial load in both directions, and a moment load.
Used in medical equipment, food machinery, semiconductor / liquid crystal manufacturing equipment, optical and optoelectronic equipment, etc.

[0002]

2. Description of the Related Art As a rolling bearing capable of receiving a radial load, an axial load in both directions, and a moment load with one bearing, a cross roller bearing and a four-point contact ball bearing are conventionally known. In the cross roller bearing, the rolling element is a roller, and the rolling element and the bearing ring make line contact at two places. In a four-point contact ball bearing, the rolling element is a ball, and the rolling element and the bearing ring make point contact at four places. Also, since there is spin sliding, the bearing clearance is generally set to be positive.

[0003]

However, cross roller bearings have the advantage of high moment rigidity, but also have the disadvantage of high torque. Four-point contact ball bearings have the advantage of low torque, but also have the disadvantage of low moment stiffness. With the downsizing of mechanical equipment, the demand for low torque and high moment stiffness for the performance of bearings capable of receiving radial loads, axial loads in both directions, and moment loads has become stronger.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to receive a radial load, an axial load in both directions, and a moment load. An object of the present invention is to provide a rolling bearing that satisfies rigidity requirements.

[0005]

In order to achieve the above object, the present invention provides a technical means in which a plurality of rolling elements are incorporated between a pair of races, and each of the races has a radius of the rolling race. Each of the rolling elements has a raceway groove composed of two larger-diameter raceway surfaces, and each of the rolling elements has an outer diameter serving as a rolling contact surface also having a curvature in the axial direction, and continuous rolling elements alternately cross each other. And the outer diameter of each rolling element is always in two-point contact with the raceway surface of one facing raceway and the raceway surface of the other raceway. This is to set the clearance to minus.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a rolling bearing according to an embodiment of the present invention. Note that this embodiment is merely an embodiment of the present invention, and is not to be construed as limiting in any way. Settings can be appropriately changed within the scope of the present invention.

The rolling bearing shown in this embodiment has a plurality of rolling elements 5, 5 between raceway grooves 3, 3 formed in the inner diameter of a raceway (outer ring) 1 and the outer diameter of a raceway (inner race) 2, respectively. ... is set and the clearance inside the bearing is set to minus (negative). The rolling elements are guided by a cage 6, and
A sealing plate 10 is arranged between the two.

The races 1 and 2 have one race (outer race) 1.
The raceway surfaces 1a and 1b and the raceway surfaces 2a and 2b formed on the inner diameter of the inner race and the outer race of the other raceway (inner race) 2 respectively form raceway grooves 3 and 3 having a desired shape. In this embodiment, The outer ring 1 is divided into two parts in the axial direction at the center in the width direction, and the inner ring 2 is not divided. In the drawing, reference numeral 4 denotes an inner ring seal groove, and 4a denotes an inner bottom of the seal groove. It should be noted that neither the bearing rings 1 and 2 are divided,
A type in which either one or both are divided into two is used.

The raceway groove 3 is formed by two raceway surfaces 1a, 1b, 2a, 2b having a radius larger than the radius of the rolling element 5. The shape of each raceway surface 1a, 1b, 2a, 2b is arbitrary, such as a cross-section arch shape or a V-shape, as long as it has a shape suitable for rolling of the rolling element 5, and a curved shape or a straight shape. Any of these may be used, and there is no particular limitation. For example, a Gothic arch or the like is applied.

The rolling element 5 has an outer diameter 5a serving as a rolling contact surface.
Has a curvature also in the axial direction, and the raceway surfaces 1a, 1b, 2a
2b is an arbitrary shape having a radius smaller than each radius, and the rolling elements 5 are arranged such that adjacent rolling elements 5 are alternately arranged in an intersecting manner, and the outer diameter 5a of each rolling element 5 is The raceway surface 1a of one raceway 1 and the raceway surface 2 of the other raceway 2 always
b or the raceway surface 1b of one raceway 1 and the raceway surface 2a of the other raceway 2 make two-point contact.

For example, as shown in FIG.
A vertically cut ball having a pair of relative surfaces 5b, 5b (a structure in which the upper and lower portions of the ball are cut to form the relative surfaces 5b, 5b; the same applies hereinafter) is applied to the relative surfaces 5b, 5b. Each of the rolling elements 5, 5... Is assembled so that the vertical rotation center axes 5c intersect with each other, and the outer diameter 5 of each of the rolling elements 5 is adjusted.
a is always the raceway surface 1a of one raceway 1 and the raceway surface 2b of the other raceway 2, or the raceway surface 1b of one raceway 1
And two contact points on the raceway surface 2a of the other raceway 2 (see FIG. 1). The contact points where the outer diameter 5a of the rolling element 5 is in point contact with the raceway surface 1a of the outer race 1 and the raceway surface 2b of the inner race 2 are indicated by reference numerals 11 and 11, and the outer diameter 5 of the cross-shaped rolling element 5 is shown.
a is the raceway surface 1b of the outer race 1 and the raceway surface 2a of the inner race 2
Reference numerals 12 and 12 denote contact points at which point contact is made.

The upper and lower cutting widths of the rolling element 5 are not particularly limited, and the upper and lower cutting ratios may be equal or not uniform, and can be arbitrarily selected within the scope of the present invention. That is, the relative surfaces 5b, 5b of the rolling elements 5
Both symmetric and asymmetric may be within the scope of the present invention.

Incidentally, the overall shape of the rolling element 5 and the relative surfaces 5b, 5
The presence or absence of b and the magnitude of the curvature in the axial direction at the outer diameter 5a are not limited to the above specific shape at all, and can be arbitrarily changed within the scope of the present invention. That is, for example, instead of the relative surfaces 5b, 5b, non-parallel surfaces may be provided, and a rotation center axis 5c perpendicular to the both surfaces may be provided. The use of a rolling element 5 'as shown in FIG. 3 is also within the scope of the present invention. That is, a rolling element 5 '(vertical cut ball) having asymmetrical relative surfaces 5b' and 5d 'is used, and the larger end 5 of the relative surfaces 5b' and 5d 'is used.
By arranging d 'so as to face the inner ring 2 of the bearing, the rotation of the rolling element 5' becomes more stable and lower torque can be realized. 5a 'indicates an outer diameter and 5c' indicates a rotation center axis. This embodiment is mainly used for high-speed rotation.

The rolling elements 5, 5,... Are assembled by the relative surfaces 5b, 5b, 5b, 5 of the adjacent rolling elements 5, 5.
The rotation center axes 5c, 5c perpendicular to b are alternately crossed, and the crossing state may be either orthogonal or non-orthogonal.

The method of arranging the rolling elements 5 in an intersecting manner is not particularly limited as long as the numbers are the same in both cases, that is, the rolling elements 5 may intersect one by one, or may intersect one by one. If the number is the same in both cases even if they do not intersect, they may intersect two by two or intersect each other, such as one by one, and both are within the scope of the present invention.

The movement of each rolling element 5, 5 is guided by a retainer 6. The retainer 6 shown in this embodiment is an annular retainer as shown in FIG. 4, and the posture of each rolling element 5 is maintained by the retainer 6.

The cage 6 is provided with a rotation center axis 5 perpendicular to the relative surfaces 5b, 5b, 5b, 5b.
The pockets 6b which can be incorporated alternately so that c and 5c cross each other are formed on the circumference of the annular body 6a.
They are arranged at equal intervals and alternately in an intersecting manner with the same quantity as the quantity. The axial side surfaces 6c and 6d of the pockets 6b are alternately parallel to each other, neither perpendicular nor parallel to the rotation axis of the bearing, and have a constant angle (inclined) at the same level as the contact angle of the rolling element 5. ing. Each pocket 6b ...
The distance between the side surfaces 6c and 6d in the axial direction is slightly larger than the width of the rolling element 5.

The shape of the pocket 6b has inclined side surfaces 6c and 6d, and both side surfaces 6c and 6d.
As long as the distance between them is slightly larger than the width of the rolling element 5, the overall shape of the pocket is not particularly limited and can be changed within the scope of the present invention.
In the present embodiment, the same number of the rolling elements 5 as the number of the pockets 6b are arranged at equal intervals and alternately in an intersecting manner on the circumference. If they are the same, they may intersect two by two or intersect two by one, which is within the scope of the present invention. The method of guiding the retainer 6 is not particularly limited, and may be inner ring guide, outer ring guide, or rolling element guide. In addition, the configuration of the retainer 6 is not particularly limited, and may be an integrated type or formed from several parts.

Spinning or skew may occur in the rotating rolling element due to the influence of various factors. If the attitude of the rolling element cannot be controlled well, the rotational resistance of the bearing may increase, or the rolling element may rotate smoothly. May not be possible. Therefore, according to this embodiment, the pocket 6b of the retainer 6 is provided with the parallel side surfaces 6c and 6d which are substantially the same as a fixed angle of the same level as the contact angle of the rolling element 5, and
By the pocket side surfaces 6c and 6d, a change in the attitude of the rolling element 5 due to spin, skew, and the like of the rolling element 5 is suppressed, and the attitude of the bearing can be maintained, so that a lower torque of the bearing can be realized.

The retainer 6 is not particularly limited as long as it has a portion for holding and guiding the rolling element 5, and can be arbitrarily selected and changed within the scope of the present invention. As the material of the retainer 6, an extruded retainer, a press retainer, a resin retainer, and the like are appropriately selected. For example, metals such as brass and iron, and polyamide 66 (nylon 66) and polyphenylene sulfide (PPS) are used. ) Are selected within the scope of the present invention.

Further, concave arc grooves 9, 9 as shown in FIG.
Even if a separator (spacer) 7 having the following is arranged, it is also within the scope of the present invention. The separator 7 includes the rolling element 5
Each rolling element 5, which is smaller in diameter than the diameter of
As described above, concave arc grooves 9, 9 holding the rotation center axes 5 c, 5 c perpendicular to the relative surfaces 5 b, 5 b, 5 b, 5 c as described above, are formed in the form of crosses with the relative surfaces 8, 8. Has formed. The curvature of the arc groove 9 may be substantially the same as or larger than the curvature of the rolling element outer diameter 5a, and may be arbitrary. By using the separator 7 in this way, the entire bearing can be made compact.

As the material of the bearing rings 1 and 2 and the rolling elements 5 of these bearings, bearing steel is usually used. However, in order to improve the corrosion resistance and heat resistance according to the use environment, a corrosion-resistant coating,
Stainless steel, heat-resistant steel (for example, M50, etc.), ceramic, and the like are appropriately selected.

The sealing plate 10 corresponds to any one of a contact type seal, a non-contact type seal, and a non-contact type shield, and the shape thereof is not particularly limited, and may have a known shape within the scope of the present invention. Are appropriately selected. In the figure, 1
Reference numeral 0a denotes a sealing surface of the sealing plate 10 which is in close contact with the inner bottom 4a of the inner ring sealing groove 4 and serves as a sealing surface.

The arrangement of the sealing plate 10 is not particularly limited, and may be arranged on both sides or on one side, if necessary, and both are within the scope of the present invention. Both the outer ring side and the inner ring side of the sealing surface are within the scope of the present invention. The shape of the seal, for example, the lip shape is not particularly limited, and even in line contact with the sealing surface, even in surface contact,
Either is within the scope of the present invention. Also, the presence or absence of the core is optional, and the type having the core and the type without the core may be properly used as needed, and there is no particular limitation. Also, the seal groove structure of the outer ring 1 and the inner ring 2 is not particularly limited, and can be appropriately changed within the scope of the present invention.
The presence or absence of the sealing plate 10 is not particularly limited, and it is within the scope of the present invention whether or not it is installed as necessary.

Example A comparative test was conducted on the torque and moment stiffness of the rolling bearing (FIG. 1), the four-point contact ball bearing, and the cross roller bearing of the above embodiment in which the internal clearance of the bearing was set to minus, respectively. .

FIGS. 6 and 7 show the results of a comparison test of the four-point contact ball bearing, the cross roller bearing, and the rolling bearing (minus clearance bearing) of the present embodiment with respect to torque and moment rigidity. According to the test results, the rolling bearing according to the present embodiment set to a minus clearance has a smaller torque than a cross roller bearing like a four-point contact ball bearing, and has a higher moment rigidity than a four-point contact ball bearing like a cross roller bearing. You can see that. That is, the rolling bearing according to the present embodiment in which the negative clearance is set has both low torque of the four-point contact ball bearing and high moment rigidity of the cross roller bearing.

[0027]

Since the present invention is constructed as described above, a bearing set with a minus clearance is a point contact type between a rolling element and a bearing ring like a four-point contact ball bearing, and a line contact type. Since the rolling resistance is smaller than that of the cross roller, the torque is reduced. Further, since a preload is applied to the inside of the bearing, a decrease in rigidity due to the internal clearance of the bearing when receiving a load can be avoided, and high moment rigidity can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view partially showing an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing one embodiment of a rolling element.

FIG. 3 is an enlarged perspective view showing another embodiment of a rolling element.

FIG. 4 is a perspective view showing one embodiment of a retainer.

FIG. 5 is a perspective view showing one embodiment of a separator.

FIG. 6 is a diagram showing a comparison test result regarding torque.

FIG. 7 is a view showing a comparison test result regarding moment rigidity.

[Explanation of symbols]

 1: Outer ring 1a, 1b: Outer ring raceway surface 2: Inner ring 2a, 2b: Inner ring raceway surface 3: Track groove 5: Rolling element 5a: Outer diameter

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J101 AA15 AA25 AA32 AA33 AA43 AA54 AA62 BA13 BA15 BA34 BA44 BA53 BA54 BA55 BA57 BA64 FA01 FA41 GA53 GA55

Claims (1)

[Claims] A plurality of rolling elements are incorporated between a pair of races, each of the races has a raceway groove composed of two raceway surfaces having a diameter larger than the radius of the rolling body. The moving body has an outer diameter that is the rolling contact surface also has a curvature in the axial direction,
Consecutive rolling elements are alternately arranged in an intersecting manner, and the outer diameter of each rolling element is always in two-point contact with the facing raceway surface of one raceway and the raceway surface of the other raceway. A rolling bearing characterized in that the internal clearance of the bearing is set to a negative value.