Outer ring spacer and bearing device equipped therewith

Abstract

The present invention provides an outer ring spacer and a bearing device equipped therewith, which can easily expand and contract in the axial direction due to the relative circumferential displacement of the two ring-shaped members when an axial force is applied, and which can expand and contract in the axial direction with a uniform axial thickness over its entire circumference. [Solution] The outer ring spacer 10 comprises first and second ring-shaped members 11 and 21, each having a plurality of first and second projections 13 and 23 arranged alternately in the circumferential direction, with one circumferential side surface of each first and second projection 13 and 23 contacting each other as inclined surfaces 14 and 24, and a plurality of elastic members 30 positioned between the other circumferential side surfaces of each first and second projection 13 and 23. The outer ring spacer 10 is expandable and contractible in the axial direction by changing the relative circumferential positions of the first ring-shaped member 11 and the second ring-shaped member 12, thereby changing the contact position of the inclined surfaces 14 and 24 of the plurality of first projections 13 and the plurality of second projections 23. At least one of the inclined surface 14 of the first projection 13 and the inclined surface 24 of the second projection 23 is spherical, and the inclined surfaces 14 and 24 make point contact with each other.

Description

Technical Field

[0001] The present invention relates to an outer ring spacer and a bearing device provided with the same, and particularly to an outer ring spacer capable of expanding and contracting in the axial direction and a bearing device provided with the same.

Background Art

[0002] In a high-speed rotating bearing device having a structure that supports both ends of a shaft with a cylindrical roller bearing and a ball bearing, one of the damages that occur in the cylindrical roller bearing on the free side is skidding wear damage caused by公转sliding. As a measure to avoid skidding damage, a method of adopting a ball bearing on the free side is known. However, in this method, when there is a heat source (mainly gears, etc.) between the free side and the fixed side, the axial elongation becomes remarkable, and an excessive load due to axial displacement is generated on the ball bearing on the shaft end side, which may lead to early damage.

[0003] To address this problem, as shown in FIG. 6, in a bearing device that supports both ends of a shaft 101 with a fixed-side bearing 102 and a free-side bearing 103 that are back-to-back combined, respectively, the fixed-side bearing 102 and the free-side bearing 103 each include a plurality of ball bearings, and an axial gap C is provided between the end face 104a of the outer ring 104 of the free-side bearing 103 and the housing 105. By not restraining the end face 104a of the outer ring 104 of the free-side bearing 103, a method of pseudo-allowing sliding is known.

[0004] Further, Patent Document 1 describes a spacer that is disposed between the fixed ring of a rolling bearing and the housing in the axial direction and can prevent loss of preload due to temperature rise. This spacer has a first member and a second member that are axially overlapped through a helically inclined overlapping surface, and a spacer body whose axial thickness varies by relatively moving the first member and the second member in the circumferential direction, and an operating member that relatively moves the first member and the second member in a direction to increase the axial thickness of the spacer body.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-10697 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, in the bearing device shown in Figure 6, if the sliding of the outer ring 104 of the free-side bearing 103 is allowed, the runout accuracy will decrease due to the outer ring 104 not being restrained. Furthermore, since the axial position depends on the expansion and contraction of the shaft 101, there remains a concern that it may catch on slight irregularities (including poor roundness) on the inner surface of the housing 105, causing unexpected internal loads due to the expansion and contraction of the shaft 101.

[0007] Furthermore, the spacer described in Patent Document 1 has overlapping surfaces that are spirally inclined and formed over almost the entire circumference, and achieving a uniform axial thickness over the entire circumference requires extremely high precision machining. Also, since the overlapping surfaces that extend over almost the entire circumference are in surface contact, the frictional force is large, and once galling occurs, there is a risk that relative movement between the first and second members will become difficult.

[0008] The present invention has been made in view of the aforementioned problems, and its objective is to provide an outer ring spacer and a bearing device equipped therewith that can be easily expanded and contracted (especially contracted) in the axial direction by the relative circumferential displacement of two ring-shaped members even when an axial force is applied, and that can expand and contract in the axial direction with a uniform axial thickness over its entire circumference. [Means for solving the problem]

[0009] The above objectives of the present invention are achieved by the configuration of the outer ring spacer described in [1] below, and the configuration of the bearing device described in [2] or [3] below. [1] A first ring-shaped member comprising a first annular portion and a plurality of arc-shaped first projections that are spaced apart in the circumferential direction from the axial end face of the first annular portion and project in the axial direction, with one circumferential side surface being an inclined surface, A second ring-shaped member comprising: a second annular portion facing the first annular portion in the axial direction; and a plurality of arc-shaped second protrusions that project axially from the axial end face of the second annular portion, spaced apart in the circumferential direction so as to be located between the plurality of first protrusions, with one circumferential side surface being an inclined surface facing the inclined surface of the first protrusion; Multiple elastic members are arranged to be expandable and contractible between the circumferential other side surfaces of the multiple first protrusions and the circumferential other side surfaces of the multiple second protrusions, and bias the multiple first protrusions and the multiple second protrusions respectively so as to bring the inclined surfaces of the multiple first protrusions and the multiple second protrusions into contact with each other. Equipped with, The first ring-shaped member and the second ring-shaped member are made expandable and contractible in the axial direction by changing their relative circumferential positions and thereby changing the contact positions between the inclined surfaces of the plurality of first protrusions and the plurality of second protrusions. At least one of the inclined surface of the first projection and the inclined surface of the second projection is spherical, and the inclined surfaces are in point contact with each other. Outer wheel spacer. [2] A bearing device in which a rotating shaft is rotatably mounted in a housing via a fixed bearing and a free bearing, The free-side bearing is an angular contact ball bearing. The outer ring spacer described in [1] is provided adjacent to the outer ring of the free-side bearing, The bearing device wherein the outer ring spacer is capable of changing its axial thickness in accordance with the axial displacement of the outer ring. [3] A bearing device in which a rotating shaft is rotatably mounted in a housing via two ball bearings arranged spaced apart in the axial direction, A bearing device comprising an outer ring spacer as described in [1], which is positioned adjacent to the outer ring of one of the two ball bearings and applies a constant pressure preload to the ball bearing. [Effects of the Invention]

[0010] According to the outer ring spacer of the present invention, at least one of the inclined surface of the first projection of the first ring-shaped member and the inclined surface of the second projection of the second ring-shaped member is spherical, and the inclined surfaces make point contact with each other. Therefore, even when an axial force is applied, the two ring-shaped members can easily expand and contract in the axial direction due to the relative circumferential displacement, and can expand and contract in the axial direction with a uniform axial thickness over the entire circumference.

[0011] Furthermore, according to the bearing device of the present invention, in which the rotating shaft is rotatably mounted in the housing via a fixed bearing and a free bearing, by using the outer ring spacer, the outer ring spacer follows the axial displacement of the outer ring of the free bearing due to shaft elongation, thereby suppressing an increase in the internal load of the rolling bearing, and the constant contact between the outer ring spacer and the outer ring prevents a decrease in runout accuracy.

[0012] Furthermore, according to the bearing device of the present invention, in which the rotating shaft is rotatably mounted in the housing via two ball bearings spaced apart in the axial direction, by using the outer ring spacer, a constant pressure preload can be applied to the ball bearings over a narrow range in the axial direction. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a cross-sectional view of a bearing device equipped with an outer ring spacer according to a first embodiment of the present invention. [Figure 2] Figure 2 is a perspective view of the outer ring spacer shown in Figure 1. [Figure 3] Figure 3 is a side view of the main part of the outer ring spacer shown in Figure 1. [Figure 4] Figure 4 is a perspective view of the main part of the outer ring spacer shown in Figure 1. [Figure 5] Figure 5 is a cross-sectional view of a bearing device equipped with an outer ring spacer according to a second embodiment of the present invention. [Figure 6] Figure 6 is a cross-sectional view of a conventional bearing device. [Modes for carrying out the invention]

[0014] Hereinafter, the outer raceway spacer of the present invention and the bearing device using the same will be described with reference to the drawings.

[0015] (First Embodiment) As shown in FIG. 1, in the bearing device 1 of the first embodiment, a rotating shaft 3 having a gear 2 is rotatably supported by a housing 6 via a fixed-side bearing 4 and a free-side bearing 5.

[0016] The fixed-side bearing 4 is composed of a plurality (three in this embodiment) of angular ball bearings that are assembled back-to-back. Each inner ring 4a is externally fitted and fixed to the rotating shaft 3, and each outer ring 4b is internally fitted and fixed to the housing body 6a of the housing 6, and is axially positioned by the stepped portions 6b and 6c of the housing 6.

[0017] On the other hand, the free-side bearing 5 is composed of a plurality (two in this embodiment) of angular ball bearings that are assembled back-to-back. Each inner ring 5a is externally fitted and fixed to the rotating shaft 3, and each outer ring 5b is internally fitted and fixed to the housing body 6d of the housing 6, and is disposed between the stepped portions 6e and 6f of the housing 6 via the outer raceway spacer 10.

[0018] Therefore, the outer raceway spacer 10 is disposed adjacent to both the end face 5b1 of one outer ring 5b of the free-side bearing 5 and the stepped portion 6e of the housing 6. Further, as will be described later, since the outer raceway spacer 10 is formed to be axially expandable and contractible, the axial thickness can be changed following the axial displacement of the outer ring 5b.

[0019] Note that the stepped portions 6b, 6c and the stepped portions 6e, 6f of the housing 6 are formed separately from the housing bodies 6a, 6d, but one of the stepped portions 6b, 6c and one of the stepped portions 6e, 6f may be integrally formed by the housing bodies 6a, 6d.

[0020] Here, as shown in FIGS. 2 to 4, the outer raceway spacer 10 includes a first ring-shaped member 11 and a second ring-shaped member 21 having substantially the same shape and dimensions as each other, and a plurality of coil springs 30 that are elastic members.

[0021] The first ring-shaped member 11 comprises a first annular portion 12 and a plurality (four in this embodiment) of arc-shaped first projections 13 that are spaced circumferentially apart from the axial end face of the first annular portion 12 and project in the axial direction. In Figure 2, a step is formed on the upper surface of the first annular portion 12 to prevent interference with the retainer.

[0022] Similarly, the second ring-shaped member 21 includes a second annular portion 22 that faces the first annular portion 12 in the axial direction, and a plurality of arc-shaped second projections 23 (four in this embodiment) that project in the axial direction from the axial end face of the second annular portion 22, spaced apart in the circumferential direction so as to be located between a plurality of first projections 13.

[0023] Furthermore, each of the multiple first projections 13 has an inclined surface 14 on one side in the circumferential direction, and each of the multiple second projections 23 also has an inclined surface 24 on one side in the circumferential direction that is opposite to the inclined surface 14 of the first projection 13. The inclined surfaces 14 and 24 are inclined in the circumferential direction so that they move toward the other side in the circumferential direction as they move away from the first annular portion 12 and the second annular portion 22 in the axial direction. Also, as shown in Figure 3, both the inclined surfaces 14 and 24 are spherical, and the inclined surfaces 14 and 24 make point contact with each other.

[0024] The multiple first protrusions 13 and the multiple second protrusions 23 are arranged alternately in the circumferential direction, and when the inclined surfaces 14 and 24 are in point contact with each other, circumferential gaps are formed between the other circumferential sides 15 of the multiple first protrusions 13 and the other circumferential sides 25 of the multiple second protrusions 23, and multiple coil springs 30 are arranged in these circumferential gaps.

[0025] In other words, the multiple coil springs 30 are each arranged to expand and contract between the circumferential other side surfaces 15 of the multiple first protrusions 13 and the circumferential other side surfaces 25 of the multiple second protrusions 23, and bias the multiple first protrusions 13 and the multiple second protrusions 23 respectively so that their inclined surfaces 14.24 come into contact with each other.

[0026] Furthermore, as shown in Figure 4, both ends of the coil spring 30 have a pair of hemispherical ball-shaped members (ball points) 31, 31 that are guided by spherical seats 16, 26 formed on the circumferential opposite side surfaces 15 of the plurality of first projections 13 and the circumferential opposite side surfaces 25 of the plurality of second projections 23.

[0027] The circumferential other side surfaces 15 of the multiple first projections 13 and the circumferential other side surfaces 25 of the multiple second projections 23 may be formed radially along a plane passing through the central axis of the outer ring spacer 10, but depending on the size of the circumferential gap, the circumferential other side surfaces 15 and 25 may be formed to be parallel to each other.

[0028] The outer ring spacer 10, configured in this way, is expandable and contractible in the axial direction by changing the relative circumferential positions of the first ring-shaped member 11 and the second ring-shaped member 21, thereby changing the contact positions of the inclined surfaces 14, 24 of the multiple first projections 13 and the multiple second projections 23.

[0029] In this configuration, the first ring-shaped member 11 and the second ring-shaped member 21 each comprise a first annular portion 12 and a second annular portion 22, and a plurality of first projections 13 and second projections 23 arranged at equal intervals in the circumferential direction. At least one of the inclined surfaces 14 of the first projection 13 and the inclined surfaces 24 of the second projection 23 is spherical, and the inclined surfaces 14 and 24 make point contact with each other. Therefore, even when an axial force is applied, the two ring-shaped members 11 and 21 can easily expand and contract in the axial direction due to the relative circumferential displacement, and can expand and contract in the axial direction with a uniform axial thickness over the entire circumference.

[0030] In the outer ring spacer 10 configured in this way, the first annular portion 12 of the first ring-shaped member 11 and the second annular portion 22 of the second ring-shaped member 12 contact the stepped portion 6e of the housing 6 and the end face 5b1 of the outer ring 5b of the free-side bearing 5, respectively. The outer ring spacer 10 follows the axial displacement of the outer ring 5b of the free-side bearing 5 due to axial elongation, thereby suppressing an increase in the internal load of the free-side bearing 5. Furthermore, the constant contact between the outer ring spacer 10 and the outer ring 5b prevents a decrease in the runout accuracy of the outer ring 5b.

[0031] Furthermore, since both ends of the coil spring 30 have a pair of hemispherical ball points 31, 31 that are guided by spherical seats 15, 25 formed on the circumferential opposite sides of the plurality of first protrusions 13 and the plurality of second protrusions 23, the coil spring 30 can be centered and stably biased regardless of the axial misalignment between the spherical seats 15 of the plurality of first protrusions 13 and the spherical seats 25 of the plurality of second protrusions 23.

[0032] (Second Embodiment) Next, a bearing device 1A of a second embodiment to which the outer ring spacer of the present invention is applied will be described with reference to Figure 5. Note that components similar to those in the first embodiment, including the outer ring spacer, are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0033] As shown in Figure 5, in the bearing device 1A of the second embodiment, the rotating shaft 3A is rotatably mounted in the housing 6 via two single-row ball bearings 7 and 8 that are spaced apart in the axial direction. The two single-row ball bearings 7 and 8 are arranged in a face-to-face configuration.

[0034] In the single-row ball bearing 7, the inner ring 7a is externally fitted and fixed to the rotating shaft 3A, and the outer ring 7b is internally fitted and fixed to the housing body 6a of the housing 6, and is positioned axially by the stepped portions 6b and 6c of the housing 6.

[0035] In the other single-row ball bearing 8, the inner ring 8a is externally fitted and fixed to the rotating shaft 3A, and the outer ring 8b is internally fitted and fixed to the housing body 6d of the housing 6, and is positioned between the outer ring spacer 10 and the stepped portions 6e and 6f of the housing 6.

[0036] In other words, the outer ring spacer 10 is positioned adjacent to the outer ring 8b of the single-row ball bearing 8 and the stepped portion 6e of the housing 6, thereby enabling constant pressure preload to be applied to the two single-row ball bearings 7 and 8.

[0037] Therefore, according to the bearing device 1A of the second embodiment, by using the outer ring spacer 10, a constant pressure preload can be applied to the ball bearings 7 and 8 over a narrower axial range compared to a general constant pressure preload structure in which a coil spring is provided between the stepped portion 6e of the housing 6 and the outer ring 8b of the single-row ball bearing 8.

[0038] It should be noted that the present invention is not limited to the embodiments described above, and can be modified or improved as appropriate. For example, in the outer ring spacer 10, both the inclined surface 14 and the inclined surface 24 are spherical, but it is sufficient that at least one of the inclined surface 14 and the inclined surface 24 is spherical, and that the inclined surfaces 14 and 24 make point contact with each other.

[0039] As described above, the following matters are disclosed in this specification: (1) A first ring-shaped member comprising a first annular portion and a plurality of arc-shaped first projections that are spaced apart in the axial direction from the axial end face of the first annular portion and project in the axial direction, with one circumferential side surface being an inclined surface, A second ring-shaped member comprising: a second annular portion facing the first annular portion in the axial direction; and a plurality of arc-shaped second protrusions that project axially from the axial end face of the second annular portion, spaced apart in the circumferential direction so as to be located between the plurality of first protrusions, with one circumferential side surface being an inclined surface facing the inclined surface of the first protrusion; Multiple elastic members are arranged to be expandable and contractible between the circumferential other side surfaces of the multiple first protrusions and the circumferential other side surfaces of the multiple second protrusions, and bias the multiple first protrusions and the multiple second protrusions respectively so as to bring the inclined surfaces of the multiple first protrusions and the multiple second protrusions into contact with each other. Equipped with, The first ring-shaped member and the second ring-shaped member are made expandable and contractible in the axial direction by changing their relative circumferential positions and thereby changing the contact positions between the inclined surfaces of the plurality of first protrusions and the plurality of second protrusions. At least one of the inclined surface of the first projection and the inclined surface of the second projection is spherical, and the inclined surfaces are in point contact with each other. Outer wheel spacer. In this configuration, at least one of the inclined surface of the first projection of the first ring-shaped member and the inclined surface of the second projection of the second ring-shaped member is spherical, and the inclined surfaces make point contact with each other. Therefore, even when an axial force is applied, the two ring-shaped members can easily expand and contract in the axial direction due to the relative circumferential displacement of the two ring-shaped members, and can expand and contract in the axial direction with a uniform axial thickness over the entire circumference.

[0040] (2) The elastic member is a coil spring, The outer ring spacer according to (1), wherein both ends of the coil spring have a pair of ball-shaped members that are guided by spherical seats formed on the circumferential other side surfaces of the plurality of first protrusions and the plurality of second protrusions. With this configuration, regardless of the axial misalignment between the spherical seats of the multiple first protrusions and the multiple spherical seats of the multiple second protrusions, the coil spring can be centered and the multiple first protrusions and the multiple second protrusions can be stably biased.

[0041] (3) A bearing device in which a rotating shaft is rotatably mounted in a housing via a fixed bearing and a free bearing, The free-side bearing is an angular contact ball bearing. The outer ring spacer described in (1) or (2) is provided adjacent to the outer ring of the free-side bearing, The bearing device wherein the outer ring spacer is capable of changing its axial thickness in accordance with the axial displacement of the outer ring. With this configuration, by using the outer ring spacer described above, the outer ring spacer follows the axial displacement of the outer ring of the free-side bearing due to axial elongation, thereby suppressing an increase in the internal load of the rolling bearing, and the constant contact between the outer ring spacer and the outer ring prevents a decrease in runout accuracy.

[0042] (4) A bearing device in which a rotating shaft is rotatably mounted in a housing via two ball bearings arranged spaced apart in the axial direction, A bearing device comprising an outer ring spacer as described in (1) or (2), which is positioned adjacent to the outer ring of one of the two ball bearings and applies a constant pressure preload to the ball bearing. With this configuration, by using the outer ring spacer described above, a constant preload can be applied to the ball bearing in a narrow range in the axial direction. [Explanation of Symbols]

[0043] 1. Bearing device 3 rotation axes 4 Fixed side bearing 5 Free side bearing 6 Housing 7,8 Single-row ball bearings 10 Outer wheel spacer 11 First ring-shaped member 12. First annular section 13 1st protrusion 14 Slope 16 Spherical seat 21 Second ring-shaped member 22 Second Ring Section 23 Second protrusion 24 Slope 26 Spherical seat 30. Coil spring (elastic component) 31. Ball Point (Ball-shaped component)

Claims

1. A first ring-shaped member comprising a first annular portion and a plurality of arc-shaped first projections that are spaced apart in the circumferential direction from the axial end face of the first annular portion and project in the axial direction, with one circumferential side surface being an inclined surface, A second ring-shaped member comprising: a second annular portion facing the first annular portion in the axial direction; and a plurality of arc-shaped second protrusions that project axially from the axial end face of the second annular portion, spaced apart in the circumferential direction so as to be located between the plurality of first protrusions, with one circumferential side surface being an inclined surface facing the inclined surface of the first protrusion; A plurality of elastic members are arranged to be expandable and contractible between the circumferential other side surfaces of the plurality of first protrusions and the circumferential other side surfaces of the plurality of second protrusions, and bias the plurality of first protrusions and the plurality of second protrusions respectively so as to bring the inclined surfaces of the plurality of first protrusions and the plurality of second protrusions into contact with each other. Equipped with, The first ring-shaped member and the second ring-shaped member are made expandable and contractible in the axial direction by changing their relative circumferential positions to each other, thereby changing the contact positions between the inclined surfaces of the plurality of first protrusions and the plurality of second protrusions. At least one of the inclined surface of the first projection and the inclined surface of the second projection is spherical, and the inclined surfaces make point contact with each other. Outer wheel spacer.

2. The elastic member is a coil spring, Both ends of the coil spring have a pair of ball-shaped members that are guided by spherical seats formed on the circumferential opposite side surfaces of the plurality of first protrusions and the plurality of second protrusions. The outer ring spacer according to claim 1.

3. A bearing device in which a rotating shaft is rotatably mounted in a housing via a fixed bearing and a free bearing, The free-side bearing is an angular contact ball bearing. The outer ring spacer according to claim 1 or 2 is provided adjacent to the outer ring of the free-side bearing, The bearing device wherein the outer ring spacer is capable of changing its axial thickness in accordance with the axial displacement of the outer ring.

4. A bearing device in which a rotating shaft is rotatably mounted in a housing via two ball bearings arranged spaced apart in the axial direction, A bearing device comprising an outer ring spacer according to claim 1 or 2, which is positioned adjacent to the outer ring of one of the two ball bearings and applies a constant pressure preload to the ball bearing.

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