Rolling bearing

Abstract

A rolling bearing includes an outer ring supported by a fixed body, an inner ring which supports a rotating shaft, and rolling elements between an inner groove of the outer ring and an outer groove of the inner ring, wherein a curvature radius R of at least the inner groove of the outer ring is in a range of 2r0.53R2r0.55 in relation to a radius r of one of the rolling elements.

Claims

1. A rolling bearing, comprising: an outer ring supported by a fixed body; an inner ring which supports a rotation shaft; and rolling elements between an inner groove of the outer ring and an outer groove of the inner ring, wherein: a curvature radius R of the inner groove of the outer ring is in a range of 2r0.53R2r0.55 in relation to a radius r of a first of the rolling elements of the rolling bearing; and the inner ring is configured to be inclined around a contact portion at which a second of the rolling elements is in contact with the inner groove of the outer ring at a load side as a fulcrum.

2. The rolling bearing according to claim 1, wherein the first of the rolling elements is at an anti-load side.

3. A rolling bearing, comprising: an outer ring supported by a fixed body; an inner ring which supports a rotation shaft; and spherical rolling elements, in a row, between an inner groove of the outer ring and an outer groove of the inner ring, wherein: a curvature radius R of the inner groove of the outer ring is along a circumference of a circle with a radius corresponding to a pitch radius of the spherical rolling elements; and the inner ring is configured to be inclined around a contact portion at which one of the spherical rolling elements is in contact with the inner groove of the outer ring at a load side as a fulcrum.

4. A ball bearing, comprising: an outer ring supported by a fixed body; an inner ring which supports a rotation shaft; and spherical rolling elements that are arranged along the outer ring at predetermined intervals in a whole circumference and between an inner groove of the outer ring and an outer groove of the inner ring, wherein: a rotation angle range of the rotation shaft is from 30 degrees to 30 degrees, and the spherical rolling elements only at an anti-load side are each formed of an elastic member.

5. A rolling bearing, comprising: an outer ring supported by a fixed body; an inner ring which supports a rotation shaft; and spherical rolling elements, in a row, between an inner groove of the outer ring and an outer groove of the inner ring, wherein: a rotation angle range of the rotation shaft is from 30 degrees to 30 degrees, and the spherical rolling elements only at an anti-load side are removed; and the inner ring is configured to be inclined around a contact portion at which one of the spherical rolling elements is in contact with the inner groove of the outer ring at a load side as a fulcrum.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of a rolling bearing according to a first embodiment of the present application.

(2) FIG. 2 is a schematic diagram of a rolling bearing according to a second embodiment of the present application.

(3) FIG. 3 is a schematic diagram of a rolling bearing according to a third embodiment of the present application.

(4) FIG. 4 is a schematic diagram of a rolling bearing according to a fourth embodiment of the present application.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) Hereinafter, embodiments according to the present application will be described in detail, based on the drawings. The application is not limited by these embodiments. Further, components in the following embodiments include any component that is easily substitutable by those skilled in the art or any component that is substantially the same.

First Embodiment

(6) FIG. 1 is a schematic diagram of a rolling bearing according to a first embodiment of the present application. As illustrated in FIG. 1, a rolling bearing 1 includes an outer ring 2 which is ring-shaped and supported by a fixed body 11, an inner ring 3 which is ring-shaped and supports a rotating shaft 12, and plural rolling elements 4 which are spherical and arranged along the ring-shaped outer ring 2 and the ring-shaped inner ring 3 between an inner groove 2a provided on an inner peripheral surface of the outer ring 2 and an outer groove 3a provided on an outer peripheral surface of the inner ring 3. That is, the rolling bearing 1 illustrated in FIG. 1 is configured as a ball bearing. Further, although not clearly illustrated in the drawings, the rolling bearing 1 has a holder provided therein, which holds the respective rolling elements 4 at a predetermined interval. Furthermore, although not clearly illustrated in the drawings, the rotating shaft 12 is connected to a driving unit such as a motor.

(7) In this rolling bearing 1, a curvature radius R of the inner groove 2a of the outer ring 2 and that of the outer groove 3a of the inner ring 3 are set to be in a range of 2r0.53R2r0.55 for a radius r of the rolling elements 4. In a general rolling bearing, a relation between a curvature radius R and a radius r is approximately in a range of 2r0.51R2r0.52. However, the curvature radii R in the rolling bearing 1 according to this embodiment are set more largely than the general. In order to make the curvature radii R and the radius r satisfy the relation 2r0.53R2r0.55, the curvature radii R are set more largely or the radius r is set smaller than the general.

(8) Normally, as illustrated in FIG. 1(a), a shaft center C of the rotating shaft 12 is in a relation of being orthogonal to an axis S in a radial direction of the rolling bearing 1. From this state, as illustrated in FIG. 1(b), the rotating shaft 12 is inclined in a direction of an arrow D due to a weight of the rotating shaft 12, a weight of a structure rotated by the rotating shaft 12, an external force acting on the rotating shaft 12, and the like. This tends to occur when the rotating shaft 12 is supported in a cantilevered manner. In association with the inclination of the rotating shaft 12, the inner ring 3 is then inclined around a contact portion at which the rolling element 4 is in contact with the inner groove 2a at a load side as a fulcrum, and the rolling elements 4 are caught and restrained between a shoulder portion of the inner groove 2a of the outer ring 2 and a shoulder portion of the outer groove 3a of the inner ring 3 at an anti-load side, and thereby rotational torque (friction torque) is increased.

(9) As described above, in the rolling bearing 1 according to this embodiment, the curvature radius R of the inner groove 2a of the outer ring 2 and that of the outer groove 3a of the inner ring 3 are set more largely than the general. Accordingly, an area of a contact ellipse in which the inner groove 2a of the outer ring 2 is in contact with the rolling element 4 and an area of a contact ellipse in which the outer groove 3a of the inner ring 3 is in contact with the rolling element 4 are smaller than the general. Therefore, the contact with the inner groove 2a and the rolling elements 4 and the contact with the outer groove 3a and the rolling elements 4 in a state where the rolling elements 4 are restrained are mitigated. As a result, increase in the rotational torque is able to be solved.

(10) In particular, the rolling bearing 1 according to this embodiment provides a prominent effect in a case where an installation space for the rolling bearing is limited and increase in the rotational torque is unable to be solved by increase in size of the rolling bearing.

(11) When the areas of the contact ellipses are decreased, a contact pressure by which the inner groove 2a of the outer ring 2 contacts the rolling element 4 and a contact pressure by which the outer groove 3a of the inner ring 3 contacts the rolling element 4 are increased. A rolling bearing having a maximum contact pressure equal to or larger than 4 [GPa] or 5 [GPa] is supposed as the rolling bearing 1 according to this embodiment. Further, a rolling bearing in which an inclination angle of the inner ring 3 is equal to or larger than 110.sup.2 [rad] is supposed as the rolling bearing 1 according to this embodiment.

(12) In the above described embodiment, both of the curvature radius R of the inner groove 2a of the outer ring 2 and that of the outer groove 3a of the inner ring 3 are set as the above. However, increase in the rotational torque is able to be solved even if the curvature radius R of at least the inner groove 2a among the inner groove 2a of the outer ring 2 and the outer groove 3a of the inner ring 3 may be set as the above, since the area of the contact ellipse in which the rolling element 4 is in contact with the inner groove 2a is decreased, and the contact with the inner groove 2a and the rolling elements 4 in a state where the rolling elements 4 are restrained is able to be mitigated.

(13) Further, in the above described embodiment, the curvature radius R of the inner groove 2a and that of the outer groove 3a are set as the above over the entire circumferences thereof. However, since the rolling elements 4 are restrained at the anti-load side, the curvature radius R of at least the inner groove 2a among the inner groove 2a and the outer groove 3a at the anti-load side may be set as the above.

(14) Further, in the above described embodiment, the relation between the curvature radius R and the radius r is in a range of 2r0.53R2r0.55. However, the relation may be in a range of 2r0.53R in terms of decreasing the area of the contact ellipse in which the rolling element 4 is in contact with the inner groove 2a as much as possible. However, the shapes of the inner groove 2a and the outer groove 3a may be formed with the shoulder portions with small curvature radius R such that the rolling elements 4 do not come off from the shoulder portions. That is, by the relation between the curvature radius R and the radius r being in the range 2r0.53R2r0.55, the rolling elements 4 are prevented from coming off from the shoulder portions of the inner groove 2a and the outer groove 3a.

Second Embodiment

(15) FIG. 2 is a schematic diagram of a rolling bearing according to a second embodiment of the present application. As illustrated in FIG. 2, a rolling bearing 1 includes an outer ring 2 which is ring-shaped and supported by a fixed body 11, an inner ring 3 which is ring-shaped and supports a rotating shaft 12, and plural rolling elements 4 which are spherical and arranged along the ring-shaped outer ring 2 and the ring-shaped inner ring 3 between an inner groove 2a provided on an inner peripheral surface of the outer ring 2 and an outer groove 3a provided on an outer peripheral surface of the inner ring 3. That is, the rolling bearing 1 illustrated in FIG. 2 is configured as a ball bearing. Further, although not clearly illustrated in the drawings, the rolling bearing 1 has a holder provided therein, which holds the respective rolling elements 4 at a predetermined interval. Furthermore, although not clearly illustrated in the drawings, the rotating shaft 12 is connected to a driving unit such as a motor.

(16) In this rolling bearing 1, a curvature radius R of the inner groove 2a of the outer ring 2 and that of the outer groove 3a of the inner ring 3 are set along a circumference of a circle with a radius corresponding to a first diameter of the rolling elements 4. The pitch radius L of the rolling elements 4 is, as illustrated in FIG. 2(a), a diameter dimension in a radial direction of plural rolling elements 4 assembled in the outer ring 2 and the inner ring 3.

(17) Normally, as illustrated in FIG. 2(a), a shaft center C of the rotating shaft 12 is in a relation of being orthogonal to an axis S in a radial direction of the rolling bearing 1. From this state, as illustrated in FIG. 2(b), the rotating shaft 12 is inclined in a direction of an arrow D due to a weight of the rotating shaft 12, a weight of a structure rotated by the rotating shaft 12, an external force acting on the rotating shaft 12, and the like. This tends to occur when the rotating shaft 12 is supported in a cantilevered manner. Conventionally, in association with the inclination of the rotating shaft 12, the inner ring 3 is then inclined around a contact portion at which the rolling element 4 is in contact with the inner groove 2a at a load side as a fulcrum, and the rolling elements 4 are caught and restrained between a shoulder portion of the inner groove 2a of the outer ring 2 and a shoulder portion of the outer groove 3a of the inner ring 3 at an anti-load side, and thereby rotational torque (friction torque) is increased.

(18) Thus, in the rolling bearing 1 according to this embodiment, as described above, the curvature radius R of the inner groove 2a of the outer ring 2 and that of the outer groove 3a of the inner ring 3 are set along the circumference of the circle with the radius corresponding to the first diameter of the rolling elements 4. That is, the curvature radius R of at least the inner groove of the outer ring is equivalent to a radius of a circle around a portion at which the rolling element is in contact with the inner groove at the load side as a center, and the inner ring is inclined around the center as a fulcrum. Therefore, the rolling elements 4 move along the inner groove 2a, and the rolling elements 4 are not restrained. As a result, increase in the rotational torque is able to be solved.

(19) In particular, the rolling bearing 1 according to this embodiment provides a prominent effect in a case where an installation space for the rolling bearing is limited and increase in the rotational torque is unable to be solved by increase in size of the rolling bearing.

(20) When the curvature radius R of the inner groove 2a of the outer ring 2 and that of the outer groove 3a of the inner ring 3 are set along the circumference of the circle with the radius corresponding to the first diameter of the rolling elements 4, an area of the contact ellipse in which the inner groove 2a of the outer ring 2 is in contact with the rolling element 4 and an area of the contact ellipse in which the outer groove 3a of the inner ring 3 is in contact with the rolling element 4 become smaller than the general. When the areas of the contact ellipses are decreased, a contact pressure by which the inner groove 2a of the outer ring 2 contacts the rolling element 4 and a contact pressure by which the outer groove 3a of the inner ring 3 contacts the rolling element 4 are increased. A rolling bearing having a maximum contact pressure equal to or larger than 4 [GPa] and less than 6 [GPa] is supposed as the rolling bearing 1 according to this embodiment. Further, a rolling bearing in which an inclination angle of the inner ring 3 is equal to or larger than 110.sup.2 [rad] is supposed as the rolling bearing 1 according to this embodiment.

(21) In the above described embodiment, since the curvature radius R of the inner groove 2a of the outer ring 2 and that of the outer groove 3a of the inner ring 3 are set along the circumference of the circle with the radius corresponding to the first diameter of the rolling elements 4, the shapes of the inner groove 2a and the outer groove 3a may be formed with the shoulder portions with small curvature radius R such that the rolling elements 4 do not come off from the shoulder portions.

(22) In the above described embodiment, both of the curvature radius R of the inner groove 2a of the outer ring 2 and that of the outer groove 3a of the inner ring 3 are set as the above. However, increase in the rotational torque is able to be solved even if the curvature radius R of at least the inner groove 2a among the inner groove 2a of the outer ring 2 and the outer groove 3a of the inner ring 3 may be set as the above, since the rolling elements 4 move along the inner groove 2a.

(23) Further, in the above described embodiment, the curvature radius R of the inner groove 2a and that of the outer groove 3a are set as the above over the entire circumferences thereof. However, since the rolling elements 4 are restrained at the anti-load side, the curvature radius R of at least the inner groove 2a among the inner groove 2a and the outer groove 3a at the anti-load side may be set as the above.

Third Embodiment

(24) FIG. 3 is a schematic diagram of a rolling bearing according to a third embodiment of the present application. As illustrated in FIG. 3, a rolling bearing 1 includes an outer ring 2 which is rig-shaped and supported by a fixed body 11, an inner ring 3 which is ring-shaped and supports a rotating shaft 12, and plural rolling elements 4 which are spherical and arranged along the ring-shaped outer ring 2 and the ring-shaped inner ring 3 between an inner groove 2a provided on an inner peripheral surface of the outer ring 2 and an outer groove 3a provided on an outer peripheral surface of the inner ring 3. That is, the rolling bearing 1 illustrated in FIG. 3 is configured as a ball bearing. Further, although not clearly illustrated in the drawings, the rolling bearing 1 has a holder provided therein, which holds the respective rolling elements 4 at a predetermined interval. Furthermore, although not clearly illustrated in the drawings, the rotating shaft 12 is connected to a driving unit such as a motor.

(25) In this rolling bearing 1, a swing angle of the inner ring 3 is set. That is, the rotating shaft 12 is configured to swing in a predetermined range (for example, from 30 to 30). In this configuration, the rolling bearing 1 has rolling elements 5 formed of an elastic member and arranged at an anti-load side away from a load region.

(26) Normally, as illustrated in FIG. 3(a), a shaft center C of the rotating shaft 12 is in a relation of being orthogonal to an axis S in a radial direction of the rolling bearing 1. From this state, as illustrated in FIG. 3(b), the rotating shaft 12 is inclined in a direction of an arrow D due to a weight of the rotating shaft 12, a weight of a structure rotated by the rotating shaft 12, an external force acting on the rotating shaft 12, and the like. This tends to occur when the rotating shaft 12 is supported in a cantilevered manner. Conventionally, in association with the inclination of the rotating shaft 12, the inner ring 3 is then inclined around a contact portion at which the rolling element 4 is in contact with the inner groove 2a at a load side as a fulcrum, and the rolling elements 4 are caught and restrained between a shoulder portion of the inner groove 2a of the outer ring 2 and a shoulder portion of the outer groove 3a of the inner ring 3 at an anti-load side, and thereby rotational torque (friction torque) is increased.

(27) Thus, as described above, the rolling bearing 1 according to this embodiment has the rolling elements 5 formed of the elastic member and arranged at the anti-load side. Therefore, by elastic deformation of the rolling elements 5, load due to restraint of the rolling elements 5 is mitigated. As a result, increase in the rotational torque is able to be solved.

(28) In particular, the rolling bearing 1 according to this embodiment provides a prominent effect in a case where an installation space for the rolling bearing is limited and increase in the rotational torque is unable to be solved by increase in size of the rolling bearing.

(29) A rolling bearing having a maximum contact pressure equal to or larger than 4 [GPa] by which the inner groove 2a of the outer ring 2 and the outer groove 3a of the inner ring 3 contact the rolling elements 4 is supposed as the rolling bearing 1 according to this embodiment. Further, a rolling bearing in which an inclination angle of the inner ring 3 is equal to or larger than 110.sup.2 [rad] is supposed as the rolling bearing 1 according to this embodiment.

Fourth Embodiment

(30) FIG. 4 is a schematic diagram of a rolling bearing according to a fourth embodiment of the present application. As illustrated in FIG. 4, a rolling bearing 1 includes an outer ring 2 which is ring-shaped and supported by a fixed body 11, an inner ring 3 which is ring-shaped and supports a rotating shaft 12, and plural rolling elements 4 which are spherical and arranged along the ring-shaped outer ring 2 and the ring-shaped inner ring 3 between an inner groove 2a provided on an inner peripheral surface of the outer ring 2 and an outer groove 3a provided on an outer peripheral surface of the inner ring 3. That is, the rolling bearing 1 illustrated in FIG. 4 is configured as a ball bearing. Further, although not clearly illustrated in the drawings, the rolling bearing 1 has a holder provided therein, which holds the respective rolling elements 4 at a predetermined interval. Furthermore, although not clearly illustrated in the drawings, the rotating shaft 12 is connected to a driving unit such as a motor.

(31) In this rolling bearing 1, a swing angle of the inner ring 3 is set. That is, the rotating shaft 12 is configured to swing in a predetermined range (for example, from 30 to 30). In this configuration, the rolling elements 4 at an anti-load side away from a load region are removed from the rolling bearing 1. In a portion where the rolling elements 4 are removed in the rolling bearing 1 of this embodiment, spacers 6 which do not contact with the outer ring 2 and the inner ring 3 are arranged. This spacer 6 corresponds, for example, to the above mentioned holder.

(32) Normally, as illustrated in FIG. 1(a), a shaft center C of the rotating shaft 12 is in a relation of being orthogonal to an axis S in a radial direction of the rolling bearing 1. From this state, as illustrated in FIG. 1(b), the rotating shaft 12 is inclined in a direction of an arrow D due to a weight of the rotating shaft 12, a weight of a structure rotated by the rotating shaft 12, an external force acting on the rotating shaft 12, and the like. This tends to occur when the rotating shaft 12 is supported in a cantilevered manner. Conventionally, in association with the inclination of the rotating shaft 12, the inner ring 3 is then inclined around a contact portion at which the rolling element 4 is in contact with the inner groove 2a at a load side as a fulcrum, and the rolling elements 4 are caught and restrained between a shoulder portion of the inner groove 2a of the outer ring 2 and a shoulder portion of the outer groove 3a of the inner ring 3 at an anti-load side, and thereby rotational torque (friction torque) is increased.

(33) Thus, as described above, since the rolling elements 4 at the anti-load side have been removed from the rolling bearing 1 according to this embodiment, the rolling elements 4 will not be restrained. As a result, increase in the rotational torque is able to be solved.

(34) In particular, the rolling bearing 1 according to this embodiment provides a prominent effect in a case where an installation space for the rolling bearing is limited and increase in the rotational torque is unable to be solved by increase in size of the rolling bearing.

(35) A rolling bearing having a maximum contact pressure equal to or larger than 4 [GPa] by which the inner groove 2a of the outer ring 2 and the outer groove 3a of the inner ring 3 contact the rolling elements 4 is supposed as the rolling bearing 1 according to this embodiment.

(36) Further, a rolling bearing in which an inclination angle of the inner ring 3 is equal to or larger than 110.sup.2 [rad] is supposed as the rolling bearing 1 according to this embodiment.

(37) According to the present application, increase in rotational torque in a case where a shaft center of a rotating shaft is inclined is able to be solved.

(38) Although this application has been described with respect to specific embodiments for a complete and clear application, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.