Bearing and rotating machine equipped therewith

Abstract

To provide: a bearing capable of preventing occurrence of creep in an outer ring and thereby appropriately maintaining a preload; and a rotating machine employing the bearing to allow the axial external dimension of a housing to be configured compactly.SOLUTION: A bearing 5 comprises: an inner ring 11 formed in an annular shape and an outer ring 12 provided on an outer peripheral side of the inner ring 11 and rotatable relative to the inner ring 11. The outer ring 12 includes an outer ring main body 21 formed in an annular shape, and an outer ring fixing portion 22 provided to protrude radially outward from the outer ring main body 21 and configured to fix the outer ring 12 to a bearing installation portion 6a at which the bearing 5 is installed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a bearing that is applicable to various devices having a rotating shaft and rotatably supports the rotating shaft, and to a rotating machine equipped with the bearing. [Background technology]

[0002] A known bearing used in a motor for rotatably supporting a shaft is described in, for example, Patent Document 1. This motor includes a pair of ball bearings (hereinafter referred to as "bearings" in this section) spaced a predetermined distance apart in the axial direction of the shaft, with a rotor through which the shaft passes between them. Each bearing is fitted into a pair of end brackets at both ends of the motor housing. A ring-shaped retaining metal fitting is attached to each end bracket's fitting hole with the bearing fitted therein. This retaining metal fitting has a ring portion with an outer diameter and an inner diameter substantially equal to the outer diameter of the bearing's outer ring and multiple locking pieces that protrude radially outward along the outer periphery of the ring portion. When the retaining metal fitting is attached to the end bracket's fitting hole, the ring portion abuts against the side of the outer ring, and the locking pieces are secured in place by engaging with the inner periphery of the fitting hole.

[0003] Another method of mounting a bearing uses an inner cover. This inner cover is formed in a ring shape with an outer diameter larger than the bearing and has multiple mounting holes on its outer periphery. When the bearing is fitted into the fitting hole, the inner cover abuts against the side of the bearing's outer ring while covering it, and is fastened to the end bracket with multiple screws inserted into each mounting hole.

[0004] In the motor using the anti-slip fittings and inner cover of Patent Document 1, the bearing is fitted into the fitting hole, and both sides of the outer ring of the bearing are clamped between the wall of the end bracket and the anti-slip fittings or inner cover, so that the bearing is firmly attached to the fitting hole of the end bracket. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-57356 Summary of the Invention [Problem to be solved by the invention]

[0006] However, if the materials used for the bearing's outer ring and the motor's housing (end bracket) are different, resulting in different linear expansion coefficients, a gap may form between the bearing's outer ring and the inner surface of the housing's fitting hole due to temperature rise during motor rotation. In this case, creep, in which the bearing's outer ring rotates circumferentially during motor rotation, may occur. If this creep occurs, the inner surface of the housing's fitting hole and the wall where the outer ring abuts wear, which could make it impossible to properly maintain the axial preload on the bearing.

[0007] Furthermore, when using the above-mentioned retaining metal fittings, the retaining metal fittings themselves must be press-fitted into the fitting holes, which requires the bearing fitting holes to be longer. On the other hand, when using a cover, space equivalent to the thickness of the cover itself is required inside the housing to accommodate the cover. Therefore, when using a retaining metal fitting or cover, the external dimensions of the motor housing in the axial direction become larger.

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a bearing that can prevent creep of the outer ring and thereby properly maintain preload, and a rotating machine that can use this bearing to enable the axial external dimensions of the housing to be configured compactly. [Means for solving the problem]

[0009] In order to achieve the above object, the invention of claim 1 is a bearing comprising an inner ring formed in a ring shape and an outer ring provided on the outer peripheral side of the inner ring and rotatable relative to the inner ring, wherein the outer ring has an outer ring main body portion formed in a ring shape and an outer ring fixing portion that protrudes radially outward from the outer ring main body portion and fixes the outer ring to a bearing installation portion on which the bearing is installed.

[0010] According to this configuration, the bearing includes the inner ring and outer ring described above, and the outer ring has a ring-shaped outer ring main body portion and an outer ring fixing portion for fixing the outer ring. The outer ring fixing portion is provided so as to protrude radially outward from the outer ring main body portion, and therefore the outer ring is fixed to the bearing installation portion via the outer ring fixing portion, allowing the bearing to be installed in the bearing installation portion with the outer ring immobile in the circumferential direction. This prevents creep, in which the outer ring rotates in the circumferential direction, even when a rotating shaft supported by a bearing of the above configuration rotates integrally with the inner ring, thereby allowing the preload on the bearing to be appropriately maintained.

[0011] The invention according to claim 2 is the bearing according to claim 1, characterized in that the outer ring fixing portion is molded integrally with the outer ring main body portion.

[0012] According to this configuration, the outer ring fixing portion is molded integrally with the outer ring main body portion, which makes it possible to manufacture the outer ring relatively easily compared to when the two are constructed as separate parts, and also makes it possible to reliably prevent creep of the outer ring.

[0013] The invention of claim 3 is characterized in that, in the bearing described in claim 2, the outer ring fixing portion is composed of multiple outer ring fixing portions arranged along the circumferential direction of the outer ring main body portion.

[0014] According to this configuration, multiple outer ring fixing portions are arranged along the circumferential direction of the outer ring main body portion, so that the outer ring can be fixed to the bearing installation portion more firmly and stably via these outer ring fixing portions.

[0015] The invention of claim 4 is characterized in that, in the bearing described in claim 3, each of the multiple outer ring fixing portions is configured to have the same thickness as the outer ring main body portion or a thickness thinner than the outer ring main body portion.

[0016] According to this configuration, when each outer ring fixing portion has the same thickness as the outer ring main body portion, the outer ring itself can be configured to be strong. On the other hand, when each outer ring fixing portion has a thickness thinner than the outer ring main body portion, less material can be used to manufacture the outer ring than when each outer ring fixing portion has the same thickness as the outer ring main body portion, thereby enabling the outer ring to be made lighter and at lower manufacturing costs.

[0017] The invention of claim 5 is characterized in that, in the bearing according to claim 4, each outer ring fixing portion is provided with a bolt hole that penetrates through the thickness direction and through which a bolt is inserted to fix the outer ring to the bearing installation portion when the bearing is installed on the bearing installation portion.

[0018] According to this configuration, each outer ring fixing portion has a bolt hole that penetrates through the thickness direction, so that by inserting a bolt into each bolt hole and screwing it into the bearing mounting portion, the bearing can be easily fixed to the bearing mounting portion via each outer ring fixing portion.

[0019] The invention of claim 6 is characterized in that, in the bearing described in claim 5, each outer ring fixing portion has a thickness thinner than the outer ring main body portion, and is provided at one end in the thickness direction of the outer ring main body portion or at the center in the thickness direction.

[0020] According to this configuration, each outer ring fixing portion, which has a thickness thinner than the outer ring main body portion, is provided at one end in the thickness direction of the outer ring main body portion or at the center in the thickness direction, so that a bearing having an outer ring that is suitable for the shape and structure of the bearing installation portion can be selected and that bearing can be properly installed in the bearing installation portion.

[0021] The invention according to claim 7 is a rotating machine having a rotating shaft, characterized in that the rotating shaft is rotatably supported by the bearing according to any one of claims 1 to 6.

[0022] According to this configuration, the rotating shaft of the rotating machine is rotatably supported by the bearings described above in claims 1 to 6, so that even when the rotating shaft rotates integrally with the inner ring of the bearing during operation of the rotating machine, creep in which the outer ring rotates in the circumferential direction can be prevented, and a rotating machine can be obtained that can appropriately maintain preload on the bearing.

[0023] An eighth aspect of the present invention is the rotating machine according to the seventh aspect, wherein the bearing is fixed to the housing of the rotating machine via an outer ring fixing portion.

[0024] This configuration allows the bearing to be easily and firmly fixed to the housing of the rotating machine via the outer ring fixing part of the bearing. Furthermore, unlike conventional rotating machines, rotating machines using this bearing do not require locking fittings or cover covers to fix the bearing, so the outer dimensions of the housing in the axial direction can be made compact. [Brief explanation of the drawings]

[0025] [Figure 1] 1A and 1B are diagrams for explaining a motor to which a bearing according to an embodiment of the present invention is applied, in which (a) is a cross-sectional view of the motor and (b) is a perspective view of the bearing. [Figure 2] 1(b), where (a) is a side view, (b) is a plan view, and (c) is a cross-sectional view taken along line cc shown in (b). [Figure 3]10A and 10B are diagrams for explaining modified examples of bearings, where (a) shows a bearing of a first modified example, and (b) shows a bearing of a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0026] A preferred embodiment of the present invention will be described in detail below with reference to the drawings. Fig. 1(a) shows a motor incorporating a bearing according to one embodiment of the present invention, cut along the rotating shaft. As shown in the figure, this motor 1 (rotating machine) includes a rotating shaft 2 having a predetermined diameter and length, a rotor 3 through which the rotating shaft 2 passes and is fixed, a stator 4 disposed radially outside the rotor 3, two bearings 5, 5 disposed on both sides of the rotor 3 and rotatably supporting the rotating shaft 2, and a housing 6 that covers the rotor 3 and stator 4 and to which the bearings 5, 5 are fixed. Note that the two bearings 5, 5 are identical, and therefore the following description will focus on the bearing 5 located on the left side of Fig. 1(a).

[0027] 1(b) and 2(a)-(c) show bearing 5, with Fig. 1(b) being a perspective view and Fig. 2(a), 2(b), and 2(c) being a side view, a plan view, and a cross-sectional view, respectively. As shown in these figures, bearing 5 comprises an inner ring 11 formed in a ring shape when viewed from above, an outer ring 12 provided radially outward of this inner ring 11 at a predetermined distance, a plurality of rolling elements 13 (only two are shown in Fig. 2(c)) arranged circumferentially between the inner ring 11 and the outer ring 12, a cage 14 that holds these rolling elements 13, and two seals 15, 15 arranged on both side surfaces (upper and lower surfaces in Fig. 2(c)) between the inner ring 11 and the outer ring 12 so as to cover all of the rolling elements 13 and cage 14. The inner ring 11, outer ring 12, rolling elements 13 and cage 14 are made of a predetermined metal, and each seal 15 is made of a predetermined metal or synthetic resin.

[0028] 2(b) and 2(c), the inner ring 11 is formed in a cylindrical shape with a predetermined inner diameter, outer diameter, and length. In addition, a raceway groove 11a of a predetermined shape is formed on the outer peripheral surface of the inner ring 11, extending over the entire circumferential direction and opening outward.

[0029] 2(a) to 2(c), the outer ring 12 has a cylindrical outer ring main body portion 21 arranged at a predetermined interval on the outer peripheral side of the inner ring 11, and multiple (three in this embodiment) outer ring fastening portions 22 protruding radially outward from one longitudinal end (the upper end portion in FIG. 2(c)) of the outer ring main body portion 21. The outer ring main body portion 21 and the multiple outer ring fastening portions 22 are molded integrally.

[0030] The outer ring main body 21 has inner and outer diameters larger than the outer diameter of the inner ring 11, and is formed in a cylindrical shape having approximately the same length as the inner ring 11. In addition, the inner peripheral surface of the outer ring main body 21 is formed with a raceway groove 21a of a predetermined shape that extends over the entire circumferential direction and opens inward.

[0031] Meanwhile, each outer ring fixing portion 22 has a predetermined thickness that is shorter than the length of the outer ring main body portion 21, is arranged at equal angles to one another along the circumferential direction of the outer ring main body portion 21, and has a planar shape that tapers radially outward and an arc-shaped tip. A bolt hole 22a through which a fixing bolt 20 (see FIG. 1(a)) is inserted is provided at the tip of each outer ring fixing portion 22. These outer ring fixing portions 22 are formed flush with one side surface of the bearing 5 (the upper surface in FIG. 2(c)), and as shown in FIG. 2(b), have a planar shape that is generally a regular triangle.

[0032] Each rolling element 13 is formed in a spherical shape having a predetermined diameter, and is configured to roll between the raceway grooves 11 a and 21 a of the inner ring 11 and the outer ring 12 .

[0033] The cage 14 is configured to engage with the rolling elements 13 and hold them between the inner ring 11 and the outer ring 12 at predetermined intervals in the circumferential direction.

[0034] The seals 15, 15 are composed of a first seal 15A arranged on one side (the upper surface in FIG. 2(c)) of the bearing 5 and a second seal 15B arranged on the other side (the lower surface in FIG. 2(c)). These first and second seals 15A and 15B can prevent foreign matter (such as dirt or moisture) from entering the gap between the inner ring 11 and the outer ring 12 from the outside, and can prevent lubricant such as grease applied to the rolling elements 13 from leaking to the outside.

[0035] As shown in FIG. 1(a), the bearings 5 ​​configured as described above are fixed to left and right bearing installation portions 6a, 6a provided on the housing 6. Each bearing installation portion 6a opens toward the inside of the housing 6 and has a predetermined shape into which the bearing 5, through which the rotating shaft 2 is inserted, fits. Therefore, while the bearing 5 installed in each bearing installation portion 6a is fitted into the bearing installation portion 6a, bolts 20 are inserted into the bolt holes 22a of the outer ring fixing portions 22 and screwed into the wall of the bearing installation portion 6a in the housing 6, thereby fixing the bearing 5 to the housing 6. At least one of the two ends of the housing 6 having the bearing installation portion 6a is configured to be detachable from the main body of the housing 6.

[0036] As described above in detail, according to this embodiment, the outer ring 12 of the bearing 5 is provided with multiple outer ring fixing portions 22 that protrude radially outward from the ring-shaped outer ring main body 21, and the bearing 5 is fixed to the bearing installation portion 6a of the housing 6 via these outer ring fixing portions 22. This allows the bearing 5 to be installed in the bearing installation portion 6a while the outer ring 12 is immobile in the circumferential direction. Therefore, even when the rotating shaft 2 rotates integrally with the inner ring 11 during operation of the motor 1, creep, in which the outer ring 12 rotates in the circumferential direction, can be prevented, and the preload on the bearing 5 can be appropriately maintained. In addition, unlike conventional motors, the motor 1 using the above-described bearing 5 does not require a retaining metal fitting or a cover to secure the bearing, and therefore the external dimensions of the housing 6 of the motor 1 in the axial direction (the left-right direction in FIG. 1(a)) can be made compact.

[0037] Furthermore, in the outer ring 12 of the bearing 5, the outer ring fixing portion 22 is molded integrally with the outer ring main body portion 21, which makes it relatively easy to manufacture the outer ring 5 compared to when the two are constructed from separate parts, and it is possible to reliably prevent creep of the outer ring 5. In addition, in the outer ring 12 of the bearing 5, multiple outer ring fixing portions 22 are arranged along the circumferential direction of the outer ring main body portion 21, so that the outer ring 5 can be fixed to the bearing installation portion 6a via these outer ring fixing portions 22 even more firmly and stably.

[0038] Furthermore, each outer ring fixing portion 22 is provided with a bolt hole 22a that penetrates in the thickness direction, so that by inserting a bolt 20 into each bolt hole 22a and screwing it into the wall of the bearing installation portion 6a in the housing 6, the bearing 5 can be easily fixed to the bearing installation portion 6a via each outer ring fixing portion 22.

[0039] 3(a) and 3(b) show first and second modified examples of the above-described bearing 5. These first and second modified bearings 5A and 5B have the same cross-sectional view as FIG. 2(c), and differ from the above-described bearing 5 only in the thickness and position of the outer ring fixing portion 22.

[0040] 3(a), the outer ring fixing portion 22 is configured to have the same thickness as the outer ring main body portion 21. In the bearing 5A of this modification, the outer ring fixing portion 22 is thicker than in the bearing 5 of the embodiment, which increases the strength of the outer ring fixing portion 22 itself and allows the bearing 5A to be firmly installed in the bearing installation portion 6a of the housing 6.

[0041] In bearing 5B of a second modified example shown in Figure 3(b), outer ring fixing portion 22 has approximately the same thickness as that of bearing 5 of the embodiment, and is located in the center in the longitudinal direction (vertical direction in Figure 3(b)) of outer ring 12. In bearing 5B of this modified example, a space is created between outer ring fixing portion 22 and the side surface of outer ring main body portion 21 (upper surface in Figure 3(b)), so that the heads of the bolts used to fix outer ring fixing portion 22 can be prevented from protruding outward beyond the side surface of outer ring main body portion 21.

[0042] As described above, by preparing multiple types of bearings 5, 5A, 5B with different thicknesses and positions of the outer ring fixing portion 22, it is possible to select a bearing having an outer ring that is suitable for the shape and structure of the bearing installation portion in the motor housing, and to properly install that bearing in the bearing installation portion.

[0043] The present invention is not limited to the above-described embodiment, and can be embodied in various forms. For example, in the embodiment, the outer ring 12 of the bearing 5 has three outer ring fixing portions 22 formed integrally with the outer ring main body portion 21. However, the number and molding method of the outer ring fixing portions 22 are not limited to those described above. As long as creep of the outer ring 12 does not occur when the motor 1 is operating, the number of outer ring fixing portions 22 can be one, two, four or more, or the outer ring fixing portions 22 can be formed separately from the outer ring main body portion 21.

[0044] Furthermore, in the embodiment, the bearing 5 of the present invention is described as being applied to a motor 1, but the present invention is not limited to this and can also be applied to rotating machines other than motors and various devices having a rotating shaft.

[0045] Furthermore, in the embodiment, the rotating shaft 2 of the motor 1 is rotatably supported by two bearings 5, 5 of the present invention, but depending on the characteristics of the motor and the usage conditions, it is also possible to use a bearing of the present invention for one of the two bearings 5, 5 on the left and right in Figure 1(a) and a general bearing for the other.

[0046] Furthermore, the detailed configurations of the motor 1, bearing 5, inner ring 11 and outer ring 12 shown in the embodiment are merely examples and can be changed as appropriate within the scope of the spirit of the present invention. [Explanation of symbols]

[0047] 1. Motor (rotating machine) 2 rotation axes 3 rotors 4 Stator 5. Bearings 5A Bearing of First Modification 5B Second modified bearing 6. Housing 6a Bearing installation section 11 Inner Circle 12 outer ring 13 Rolling elements 14 Cage 15 Seals 15A 1st seal 15B Second Seal 20 volts 21 Outer ring body 22 Outer ring fixing part 22a Bolt hole

Claims

1. A bearing comprising an inner ring formed in a ring shape and an outer ring provided on the outer periphery of the inner ring and rotatable relative to the inner ring, The outer ring includes an outer ring main body formed in a ring shape, an outer ring fixing portion that protrudes radially outward from the outer ring main body portion and fixes the outer ring to a bearing installation portion on which the bearing is installed; and A bearing comprising:

2. 2. The bearing according to claim 1, wherein the outer ring fixing portion is molded integrally with the outer ring main body portion.

3. 3. The bearing according to claim 2, wherein the outer ring fixing portion is made up of a plurality of outer ring fixing portions arranged along the circumferential direction of the outer ring main body portion.

4. 4. The bearing according to claim 3, wherein each of the plurality of outer ring fixing portions is configured to have the same thickness as the outer ring main body portion or a thickness thinner than the outer ring main body portion.

5. 5. The bearing according to claim 4, characterized in that each outer ring fixing portion is provided with a bolt hole that penetrates the outer ring fixing portion in the thickness direction and through which a bolt is inserted for fixing the outer ring to the bearing installation portion when the bearing is installed on the bearing installation portion.

6. 6. The bearing according to claim 5, wherein each of the outer ring fixing portions has a thickness thinner than that of the outer ring main body portion, and is provided at one end portion in the thickness direction of the outer ring main body portion, or at the center portion in the thickness direction.

7. A rotating machine having a rotating shaft, A rotating machine, characterized in that the rotating shaft is rotatably supported by the bearing according to any one of claims 1 to 6.

8. 8. The rotating machine according to claim 7, wherein the bearing is fixed to a housing of the rotating machine via the outer ring fixing portion.

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