JP3424875B2 - Slewing bearing spacer retainer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary bearing and a joint for an industrial robot, a rotary table for a rotary center of a machining center, and the like. The present invention relates to a spacer retainer that holds rollers arranged between these inner and outer rings in a predetermined posture. 2. Description of the Related Art Heretofore, as this kind of spacer retainer, there has been known a spacer retainer used for a so-called cross roller type slewing bearing (Japanese Utility Model Laid-Open No. 59-1928, Japanese Utility Model Publication No. 6-25704). No.). In this type of slewing bearing, the perpendicular V of two roller rolling surfaces
A letter-shaped groove is formed on each of the inner ring and the outer ring, and the rollers are arranged between the V-shaped grooves so that their inclination directions intersect alternately. The spacer retainers are inserted between the rollers adjacent to each other, and hold the right and left adjacent rollers in a predetermined posture such that the rotation center of each roller always faces the rotation axis of the inner ring and the outer ring. . Therefore, the conventional spacer retainer is formed in a substantially rectangular shape, and two opposing surfaces facing the roller are formed in an arc shape corresponding to the outer peripheral surface of the roller. It is configured to hold the roller in a predetermined posture while holding the outer peripheral surface of the roller. Further, a conventional spacer retainer is formed with a through hole for grease so as to communicate the above-mentioned pair of holding contact surfaces, and grease supplied to the through hole for grease periodically is used. Care is taken to ensure lubrication between the rollers and the inner and outer rings. However, in the conventional spacer retainer configured as described above, when the spacer is arranged together with the roller, the through hole for the oil reservoir formed in the holding contact surface is formed by the roller. Even if the grease is regularly supplied between the inner and outer rings using a grease gun or the like, the grease cannot be sufficiently retained in the grease reservoir through-holes. Therefore, in a slewing bearing using such a spacer retainer, there has been a problem that short-time use causes insufficient lubrication between the roller and the inner and outer rings, causing galling of the roller and the inner and outer rings. Also, due to dimensional errors during molding of the spacer retainer, when the rollers and the spacer retainers are arranged all around the inner and outer rings, a gap is easily generated between the spacer retainers and the rollers. There is also a problem that the orientation of the roller during rotation of the slewing bearing tends to become unstable due to the occurrence. SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a roller which can sufficiently retain grease against external grease supply to a slewing bearing for a long time. To provide a slewing bearing spacer retainer that can sufficiently lubricate the bearing. Another object of the present invention is to prevent a gap from being formed between rollers and inner and outer races of a slewing bearing, and to stably hold the rollers in a predetermined posture at all times. To provide a slewing bearing spacer retainer that is capable of performing the following. [0009] That is, the spacer retainer of the present invention that achieves the above-mentioned object has a plurality of rollers alternately arranged between an inner ring and an outer ring of a slewing bearing, and a roller adjacent to the right and left is provided. A spacer retainer for holding a predetermined posture, wherein a pair of side plate portions are connected by a substrate portion to form a substantially U-shaped cross section, and a space sandwiched between the pair of side plate portions is used as a grease storage portion, The holding contact surfaces of the rollers adjacent to the left and right are provided on each of the side plates, or the holding contact surfaces are provided on the open ends of the substrate and the side plates. [0010] In the spacer retainer of the present invention in which the pair of side plates are connected by the substrate as described above, the space between the pair of side plates is open toward three sides of the peripheral edge of the side plate. Can be used as a grease reservoir. However, in order to make the grease in and out of the grease reservoir smoothly, at least two of the three opening directions are not blocked by the adjacent rollers, and the roller rolling of the slewing bearing is performed. It must be open to the running surface. Therefore, from such a viewpoint, the holding contact surface of the roller provided in the spacer retainer of the present invention is provided on each of the side plate portions, or is provided on the open ends of the substrate portion and each of the side plate portions. That is, by providing the holding contact surface of the roller in this way, the grease reservoir portion opened in three directions is opened at least in two opposite directions toward the roller rolling surfaces of the inner ring and the outer ring. Further, in order to directly supply the grease held in the grease reservoir to the peripheral surface of the roller, a holding contact surface of the roller is provided at the open end of each side plate as in the latter case, and the pair of side plate portions is provided. Preferably, the roller is held so as to straddle the open end. In this case, the peripheral surface of the roller always faces the grease reservoir. Further, in the case where the holding contact surface of the roller is provided at the open end of each side plate portion, in order to enhance the stability of the contact between the roller and the spacer retainer, the open end is directed toward the side of the side plate portion. It is preferable to provide an overhang projecting from the projection. The spacer retainer of the present invention can be manufactured by injection molding of a synthetic resin or pressing of a sheet metal. Since the roller rotates while rubbing against the holding contact surface of the spacer retainer, the former uses an oil-containing resin as the injection molding material, while the latter uses a coating process such as a resin film after molding (for example, Teflon coating or the like). ) Is preferred. By doing so, the frictional resistance acting on the roller from the spacer retainer can be reduced. When such a spacer retainer is manufactured from sheet metal, it is preferable to perform a surface hardening treatment such as a molybdenum disulfide treatment or a plating treatment after the molding in order to enhance abrasion resistance. According to the present invention, the spacer retainer is formed in a substantially U-shaped cross-section by connecting the pair of side plates with the substrate, and the space between the pair of side plates is a grease reservoir. The grease reservoir is closed by the arrangement of the rollers because the holding contact surfaces of the rollers adjacent to the left and right are formed at the open ends of the pair of side plates or the substrate and the side plates. The roller is always open in the direction of the inner and outer races where the rollers roll. Therefore, the grease supplied to the slewing bearing can be sufficiently held in the grease reservoir. Further, in the spacer retainer having such a structure, one side plate portion is slightly displaced relative to the other side plate portion, so that the distance between a pair of right and left adjacent rollers is reduced accordingly. The adjustment can be performed by the spacer retainer, and the generation of a gap between the roller and the spacer retainer can be prevented as much as possible. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a spacer retainer according to the present invention will be described in detail with reference to the accompanying drawings. FIGS. 1 and 2 show an example of a cross roller type slewing bearing B using the spacer retainer of the present invention. In the figure, reference numeral 1 denotes an outer ring having two roller rolling surfaces 11 along the circumferential direction of the inner peripheral surface, and reference numeral 2 denotes an inner ring having two rolling surfaces 21 facing the outer ring-side rolling surface 11. Reference numeral 3 denotes rollers arranged between the outer race side rolling surface 11 and the inner race side rolling surface 21 facing each other. The outer race 1 is divided into two parts along the circumferential direction and is connected to each other by bolts (not shown). The rolling surfaces 11 and 11 are formed on each of the pair of divided annular members 1a and 1b.
They meet at an angle of 0 °. In addition, the outer race side rolling surface 11,
11 are also at 90 ° to each other.
, And together with the outer race side rolling surfaces 11, 11, form an annular orbit on which the roller 3 rolls. In this annular track, the rollers 3 are alternately arranged with the spacer retainers 4, and a pair of rollers 3 adjacent to the left and right of the spacer retainers 4 have their axial directions orthogonal to each other. The rotation axis of the pair of rollers 3 adjacent to the left and right of the spacer retainer 4 is always the rotation center P on the rotation axis O of the outer ring 1 and the inner ring 2.
To face _one or P _2, it holds the roller adjacent to the right and left in a predetermined posture. FIGS. 3 and 4 show a first embodiment of the spacer retainer 4 of the present invention. The spacer retainer 4 is formed by connecting a pair of side plate portions 41 parallel to each other by a substrate portion 42 and has a substantially U-shaped cross section. The open end 41 a of each side plate portion is formed in an arc shape as a holding contact surface of the roller 3. On the other hand, the substrate portion 42 is formed in a curved shape as a holding contact surface of the roller 3. In this case, the substrate section 42
Since the rotation axis of the roller 3 contacting with the roller 3 is orthogonal to the roller 3 contacting the open end 41a of the side plate portion 41,
The substrate part 42 has a circular arc connecting the pair of side plate parts 41,41. In the spacer retainer according to the present embodiment having the above-described structure, a space 43 is formed between the pair of side plate portions 41, 41. This space 43 functions as a grease reservoir. In addition, even if rollers are disposed adjacent to the left and right of the spacer retainer 4, the grease reservoir 43 is not closed by the rollers 3, and always faces the outer race side rolling surface 11 and the inner race side rolling surface 21. It is open. Therefore, when grease is supplied between the outer ring 1 and the inner ring 2 using a grease gun or the like, the grease easily flows into the grease reservoir 43 of the spacer retainer 4,
Since the grease can be sufficiently held in the grease reservoir 43, a good lubrication state can be maintained for a long period of time. If the spacer retainers 4 are arranged so that the open ends of the side plate portions 41 are directed in the same circumferential direction (for example, the direction of the arrow A shown in FIG. 3) over the entire circumference of the slewing bearing, the individual rollers Thus, the grease reservoir 43 faces the roller 3, and all the rollers 3 arranged on the annular track can be lubricated satisfactorily. FIGS. 5 and 6 show a second embodiment of the spacer retainer of the present invention. The spacer retainer 5 of this embodiment has substantially the same configuration as that of the first embodiment described above, and a pair of side plate portions 51 which are also parallel to each other are connected by a substrate portion 52 to form a substantially U-shaped cross section. Is formed. Further, the open end 51a of the side plate portion 51 is cut out in an arc shape, and the substrate portion 52 is formed in a curved shape. However, in this embodiment, each side plate portion 51,5
A projecting portion 54 is formed at the open end of the projection 1 so as to project orthogonally to the side plate portion 51. Accordingly, since the contact area between the open end 51a of the side plate portion 51 and the roller is wider than in the first embodiment, the stabilization of the posture of the roller 3 during rolling can be expected. FIGS. 7 and 8 show a third embodiment of the spacer retainer of the present invention. Also in this embodiment, the spacer retainer 6 is formed in a substantially U-shaped cross-section by connecting a pair of side plate portions 61 parallel to each other by the substrate portion 62, and a projecting portion 64 is formed at the open end 61 a of the side plate portion 61. 5 and FIG. 7, as apparent from the comparison between FIGS. 5 and 7, the roller 3 contacting the open end 61a of the side plate portion 61.
Is in a relationship orthogonal to that in the second embodiment. That is, the rotation axis of the roller 3 contacting the open end 61a of the side plate 61 is parallel to the side plate 61, while the rotation axis of the roller 3 contacting the substrate 62 is orthogonal to the side plate 61. ing. Therefore, as shown in FIG. 8, in this embodiment, the projecting portion 64 formed on each side plate portion 61 has a shape along the peripheral surface of the roller 3. FIGS. 9 and 10 show a fourth embodiment of the spacer retainer according to the present invention. Also in this embodiment, the spacer retainer 7 is formed in a substantially U-shaped cross section by connecting a pair of side plate portions 71 parallel to each other by the substrate portion 72, but the holding contact surfaces of the rollers 3 adjacent to the right and left are It is formed on each side plate portion 71, 71. That is, in this embodiment, each of the side plate portions 71 is formed in a curved shape corresponding to the peripheral shape of the roller 3, and the substrate portion 72 is formed in a planar shape. Therefore, in the spacer retainer 7, the grease reservoir 73 sandwiched between the pair of side plates 71, 71
It is opened in three directions without being closed by the roller 3 adjacent to the spacer retainer 7, so that grease flows into the grease reservoir 73 more easily than in the previous embodiment. In this embodiment, when the pair of side plate portions 71 is pressed from the outside, the distance between the adjacent rollers slightly changes due to the displacement of each side plate portion 71 inward. If the pressing force applied to all the spacer retainers is acting in a state where the rollers are arranged in a row, each roller 3 and the side plate portion 71 of the spacer retainer 7 come into close contact with no gap. Therefore, if the side plate 71 is slightly pressed and inserted between the rollers 3 adjacent to each other, and this is performed over the entire circumference of the annular track, a gap is generated between each roller 3 and the spacer retainer 7. Therefore, the posture of the roller 3 during rolling can be stabilized. As described above, the spacer retainer of the slewing bearing according to the present invention has a structure in which the grease reservoir portion sandwiched between the pair of side plates always moves in the direction of the inner and outer races where the rollers roll. The grease reservoir is not closed by the right and left adjacent rollers, so that the grease supplied to the slewing bearing can be sufficiently held in the grease reservoir, and the slewing bearing Can be maintained in a good state over a long period of time. Further, in the spacer retainer of the slewing bearing according to the present invention, the distance between the pair of side plates is slightly changed by being pressed by the right and left adjacent rollers,
The distance between the adjacent rollers on the left and right can be adjusted by this spacer retainer, so that the generation of a gap between the roller and the spacer retainer is prevented as much as possible, and the roller attitude during rolling is stable. It is possible to obtain a smooth rotation of the inner ring or the outer ring.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front sectional view showing a slewing bearing in which a spacer retainer of the present invention is used. FIG. 2 is a partially cutaway plan view showing an arrangement of rollers in the slewing bearing of FIG. 1; FIG. 3 is a perspective view showing a first embodiment of the spacer retainer of the present invention. FIG. 4 is a front view of the spacer retainer according to the first embodiment. FIG. 5 is a perspective view showing a second embodiment of the spacer retainer of the present invention. FIG. 6 is a front view of a spacer retainer according to a second embodiment. FIG. 7 is a perspective view showing a third embodiment of the spacer retainer of the present invention. FIG. 8 is a front view of a spacer retainer according to a third embodiment. FIG. 9 is a perspective view showing a fourth embodiment of the spacer retainer of the present invention. FIG. 10 is a front view of a spacer retainer according to a fourth embodiment. [Description of Signs] 1 ... Outer ring, 2 ... Inner ring, 3 ... Roller, 4 ... Spacer retainer, 41 ... Side plate part, 42 ... Substrate part, 43 ... Grease reservoir part, B ... Slewing bearing

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16C 19/00-19/56 F16C 33/30-33/66

Claims (1)

(57) [Claim 1] A spacer retainer which is alternately arranged with a number of rollers between an inner ring and an outer ring of a slewing bearing, and which holds left and right adjacent rollers in a predetermined posture, A pair of side plate portions are connected to each other by a substrate portion to form a substantially U-shaped cross section, a space sandwiched between the pair of side plate portions is used as a grease reservoir, and a holding contact surface of a roller adjacent to the left and right is a substrate portion. And, provided at the open end of each side plate portion , further, at the open end of each side plate portion as a holding contact surface of the roller,
An overhang protruding from the open end toward the side of the side plate
Spacer retainer, characterized in that the provided.