JP2024051237A - Bearing Structure - Google Patents

Abstract

To provide a bearing that reduces an increase in manufacturing cost without increasing the number of components of the bearing.SOLUTION: A bearing 12 of a bearing structure 10 comprises rotation restraining protrusions 24 protruding in an axial direction from at least one side surface out of a first side surface 26 and a second side surface 28. First and second protrusions 46 and 48 of the rotation restraining protrusions 24 each has a V-shape comprising a vertex facing in a circumferential direction of the bearing 12. A supporting member 14 comprises first and second wall surfaces 52 and 54 facing the rotation restraining protrusions 24. When an inner ring 20 rotates, fluid L is supplied between first and second outer ring side surfaces 32 and 34 comprising the first and second protrusions 46 and 48 and the first and second wall surfaces 52 and 54 respectively.SELECTED DRAWING: Figure 4

Description

The present invention relates to a bearing structure having a bearing with an inner ring and an outer ring, and a support member that fixes the outer ring.

When a ferrous metal bearing is mounted in a housing made of a non-ferrous metal material, the heat generated as the bearing rotates causes both the bearing and the housing to thermally expand. At this time, the housing, which has a large coefficient of thermal expansion, thermally expands more than the bearing, and the gap between the bearing and the housing may widen. This gap causes the bearing to rotate relative to the housing, raising concerns that the durability of the bearing may decrease.

In the bearing structure of Patent Document 1, a bearing is mounted in a housing. The side of the outer ring has a ring-shaped recess. A high thermal expansion member made of a non-ferrous metal is mounted in the recess. The high thermal expansion member is positioned to face the inner surface of the housing. When the bearing heats up, the high thermal expansion member expands and comes into contact with the housing. This prevents the bearing from rotating relative to the housing.

Japanese Utility Model Application Publication No. 3-2921

However, the bearing structure of Patent Document 1 requires processing to form a recess on the side of the outer ring, which increases manufacturing costs and manufacturing man-hours. The need for a high thermal expansion material increases the number of parts in the bearing and manufacturing costs.

The present invention aims to solve the above-mentioned problems.

The present invention relates to a bearing structure comprising an outer ring, an inner ring arranged inside the outer ring and capable of rotating relative to the outer ring, a plurality of rolling elements arranged between the inner ring and the outer ring, and a support member formed of a material having a thermal expansion coefficient larger than that of the outer ring and to which the outer ring is fixed, the bearing having an annular first side surface facing one axial side of the bearing and an annular second side surface facing the other axial side, the bearing having a rotation suppressing protrusion protruding in the axial direction from at least one of the first side surface and the second side surface, the rotation suppressing protrusion being formed in a V-shape having an apex facing the circumferential direction of the bearing, the support member having a wall surface facing the rotation suppressing protrusion in the axial direction, and a fluid being supplied between the wall surface and the side surface on which the rotation suppressing protrusion is arranged when the inner ring rotates.

According to the present invention, when the inner ring of the bearing rotates, a fluid (liquid lubricant or coolant) is supplied between the side of the bearing and the wall surface of the support member, and the rotation suppression protrusion generates dynamic pressure in the gap between the side of the bearing and the wall surface of the support member. This makes it possible to generate a load in the thrust direction (axial direction) on the bearing and suppress the relative rotation of the outer ring supported by the support member with a simple configuration of providing a rotation suppression protrusion. As a result, it is possible to improve the durability of the bearing while reducing the number of parts, manufacturing costs, and manufacturing labor, compared to a configuration in which the bearing has a recess and a high thermal expansion member.

FIG. 1 is an overall cross-sectional view showing a bearing structure according to a first embodiment of the present invention. FIG. 2 is an overall front view of the bearing shown in FIG. 1 as seen from a first side surface side. FIG. 3 is an overall front view of the bearing shown in FIG. 1 as seen from the second side surface side. FIG. 4 is an enlarged cross-sectional view of the bearing structure of FIG. 5 is an enlarged front view showing the vicinity of the first projection of the outer ring in FIG. 2 . 6 is an enlarged front view showing the vicinity of the second projection of the outer ring of FIG. 3. FIG. FIG. 7 is an enlarged cross-sectional view showing a state in which the bearing has moved axially due to dynamic pressure generated by the rotation suppressing protrusion. FIG. 8 is an overall cross-sectional view of a bearing structure according to a second embodiment of the present invention. FIG. 9 is an enlarged cross-sectional view of the bearing structure of FIG. FIG. 10 is an overall front view of the bearing shown in FIG. 8 as viewed from the first side surface side. FIG. 11 is an overall front view of the bearing shown in FIG. 8 as viewed from the second side surface side. 12 is an enlarged front view showing the vicinity of the second projection of the inner ring shown in FIG. 11. FIG. FIG. 13 is an enlarged cross-sectional view showing a state in which the bearing has moved axially due to dynamic pressure generated by the rotation suppressing projection.

As shown in FIG. 1, the bearing structure 10 according to the first embodiment includes a bearing 12 and a support member 14 to which the bearing 12 is fixed. The bearing 12 is fixed in a mounting groove 16 of the support member 14.

The bearing 12 includes an outer ring 18, an inner ring 20, a plurality of rolling elements 22, and a rotation suppression protrusion 24. The outer ring 18 is fixed to the mounting groove 16 of the support member 14, and the inner ring 20 is supported so as to be rotatable relative to the outer ring 18. Below, we will explain the case where the rotation direction R of the inner ring 20 is counterclockwise when the bearing 12 is viewed in the axial direction from the first side surface 26 side shown in Figure 2.

The bearing 12 has a first side 26 and a second side 28. The first side 26 is an annular side that faces one side in the axial direction of the bearing 12. The second side 28 is an annular side that faces the other side in the axial direction of the bearing 12.

As shown in FIG. 2, the outer ring 18 is made of a metal material and has a circular ring shape with a central axis. The outer ring 18 is accommodated and fixed in the mounting groove 16 of the support member 14 (see FIG. 1). The outer peripheral surface of the outer ring 18 is annular. The inner circumference of the outer ring 18 has an annular first rolling groove 30. The first rolling groove 30 is a groove in which multiple rolling elements 22 can roll. The first rolling groove 30 is recessed radially outward from the inner peripheral surface of the outer ring 18.

The outer ring 18 has a first outer ring side surface 32 and a second outer ring side surface 34. The first outer ring side surface 32 is formed in an annular shape and constitutes a part of the first side surface 26. As shown in FIG. 3, the second outer ring side surface 34 is formed in an annular shape and constitutes a part of the second side surface 28.

As shown in FIG. 4, the first outer ring side surface 32 and the second outer ring side surface 34 are spaced apart in the axial direction of the outer ring 18. The first and second outer ring side surfaces 32, 34 are flat surfaces perpendicular to the axial direction of the outer ring 18. The first outer ring side surface 32 and the second outer ring side surface 34 are parallel.

As shown in FIG. 2, the inner ring 20 is made of a metal material and has a circular shape with a central axis. The inner ring 20 is disposed inside the outer ring 18. The inner ring 20 is disposed so as to be rotatable relative to the outer ring 18. The center of the inner ring 20 has a shaft hole 36. The shaft hole 36 passes through the inner ring 20 in the axial direction. A rotating shaft 38 is inserted and supported in the shaft hole 36 (see FIG. 1). The inner ring 20 and the rotating shaft 38 rotate together.

As shown in FIG. 4, the outer periphery of the inner ring 20 has an annular second rolling groove 40. The second rolling groove 40 is a groove in which multiple rolling elements 22 can roll. The second rolling groove 40 is recessed radially inward from the outer periphery of the inner ring 20. The first rolling groove 30 and the second rolling groove 40 face each other. Multiple rolling elements 22 are arranged between the first rolling groove 30 and the second rolling groove 40.

The inner ring 20 has a first inner ring side surface 42 and a second inner ring side surface 44. As shown in FIG. 2, the first inner ring side surface 42 is formed in an annular shape and constitutes a part of the first side surface 26. As shown in FIG. 3, the second inner ring side surface 44 is formed in an annular shape and constitutes a part of the second side surface 28.

As shown in FIG. 4, the first inner ring side surface 42 and the second inner ring side surface 44 are spaced apart in the axial direction of the inner ring 20. The first and second inner ring side surfaces 42, 44 are flat surfaces perpendicular to the axial direction of the inner ring 20. The first inner ring side surface 42 and the second inner ring side surface 44 are parallel. In the axial direction of the bearing 12, the first inner ring side surface 42 and the first outer ring side surface 32 are disposed at approximately the same position, and the second inner ring side surface 44 and the second outer ring side surface 34 are disposed at approximately the same position.

The multiple rolling elements 22 are disposed between the outer periphery of the inner ring 20 and the inner periphery of the outer ring 18. The rolling elements 22 are, for example, spherical balls. Each rolling element 22 is inserted between the first rolling groove 30 of the outer ring 18 and the second rolling groove 40 of the inner ring 20. The multiple rolling elements 22 are movable in the circumferential direction along the first and second rolling grooves 30, 40. The multiple rolling elements 22 allow the inner ring 20 to rotate relative to the outer ring 18.

The rotation suppressing protrusion 24 can suppress the relative rotation of the outer ring 18 with respect to the support member 14. The rotation suppressing protrusion 24 protrudes in the axial direction from at least one of the first side surface 26 and the second side surface 28. The rotation suppressing protrusion 24 is disposed on the outer ring 18. The rotation suppressing protrusion 24 has a first protrusion 46 and a second protrusion 48.

As shown in FIG. 2, the first protrusion 46 is disposed on the first outer ring side surface 32, which is part of the first side surface 26. As shown in FIG. 3, the second protrusion 48 is disposed on the second outer ring side surface 34, which is part of the second side surface 28.

As shown in FIG. 4, the first protrusion 46 protrudes in the axial direction from the first outer race side surface 32. The first protrusion 46 is, for example, a printed body printed on the first outer race side surface 32 by a printer. The first protrusion 46 protrudes from the first outer race side surface 32 by the ink of the printer.

As shown in FIG. 5, the first projection 46 is V-shaped. The first projection 46 has an apex 46a and a hem 46b. The apex 46a is located at the tip of the first projection 46. The apex 46a is tapered toward the tip. The hem 46b is located at the base end of the first projection 46. The hem 46b gradually expands in a bifurcated shape in the direction away from the apex 46a. The ends of the hem 46b extend to the vicinity of the outer edge and inner edge of the first outer ring side surface 32.

When the first outer ring side surface 32 is viewed from the axial direction of the outer ring 18 shown in FIG. 2, the apex 46a of the first projection 46 is disposed in a counterclockwise circumferential direction. In other words, the apex 46a is disposed in the rotational direction R of the inner ring 20. The bottom portion 46b of the first projection 46 is disposed in a position clockwise (counter-rotational direction) from the apex 46a in the circumferential direction.

As shown in FIG. 2, the first protrusions 46 are arranged in a plurality of positions along the circumferential direction of the outer ring 18. The plurality of first protrusions 46 are arranged at equal intervals in the circumferential direction of the outer ring 18. The plurality of first protrusions 46 constitute a first protrusion portion 461. The plurality of first protrusion portions 461 are arranged. The plurality of first protrusion portions 461 are arranged at equal intervals in the circumferential direction of the outer ring 18. Here, as shown in FIG. 2, a case where three first protrusion portions 461 are provided will be described. The first protrusions 46 (first protrusion portions 461) may be arranged on a portion of the first outer ring side surface 32, or may be arranged over the entire circumferential direction of the first outer ring side surface 32.

As shown in FIG. 4, the second protrusion 48 protrudes in the axial direction from the second outer ring side surface 34. The second protrusion 48 is, for example, a printed body printed on the second outer ring side surface 34 by a printer. The second protrusion 48 protrudes from the second outer ring side surface 34 by ink from the printer. The first protrusion 46 and the second protrusion 48 protrude in opposite directions from each other in the axial direction of the central axis of the outer ring 18.

As shown in FIG. 6, the second protrusion 48 is V-shaped. The second protrusion 48 has the same shape as the first protrusion 46. Therefore, the same reference numerals are used for the same configuration as the first protrusion 46, and detailed description is omitted.

When the second outer ring side surface 34 is viewed from the axial direction of the outer ring 18 shown in FIG. 3, the apex 48a of the second projection 48 is disposed in a counterclockwise circumferential direction. The bottom portion 48b of the second projection 48 is disposed in a clockwise position relative to the apex 48a in the circumferential direction. The rotation direction R of the inner ring 20 in FIG. 3 is clockwise.

That is, the apex 46a of the first protrusion 46 is arranged facing the rotation direction R of the inner ring 20, and the apex 48a of the second protrusion 48 is arranged facing the opposite direction (reverse direction) to the rotation direction R of the inner ring 20. In the circumferential direction of the outer ring 18, the apex 46a of the first protrusion 46 and the apex 48a of the second protrusion 48 are arranged facing in opposite directions to each other.

As shown in FIG. 3, multiple second protrusions 48 are arranged in the circumferential direction of the outer ring 18. The multiple second protrusions 48 are arranged at equal intervals in the circumferential direction of the outer ring 18. The multiple second protrusions 48 constitute a second protrusion portion 481. Multiple second protrusion portions 481 are arranged. The multiple second protrusion portions 481 are arranged at equal intervals in the circumferential direction of the outer ring 18. Here, a case where three second protrusions 481 are provided as shown in FIG. 3 will be described.

The second protrusion 48 (second protrusion portion 481) may be disposed on a portion of the second outer ring side surface 34, or may be disposed over the entire circumferential direction of the second outer ring side surface 34.

As shown in FIG. 1, the support member 14 is made of a metal material such as aluminum. The material of the support member 14 has a higher thermal expansion coefficient than the material of the outer ring 18. In other words, the support member 14 is made of a material that has a higher thermal expansion coefficient than the outer ring 18.

The support member 14 has an annular mounting groove 16. The mounting groove 16 faces the outer ring 18 of the bearing 12, into which the outer ring 18 is inserted and fixed. The mounting groove 16 is recessed in a direction radially away from the central axis of the bearing 12. When viewed from a direction perpendicular to the axial direction of the central axis of the bearing 12 shown in Figure 1, the cross section of the mounting groove 16 is rectangular.

As shown in FIG. 4, the mounting groove 16 has a peripheral wall 50 and a pair of first and second wall surfaces 52, 54. The peripheral wall 50 is disposed radially outward of the mounting groove 16. The peripheral wall 50 is parallel to the central axis of the bearing 12. The peripheral wall 50 faces the outer peripheral surface of the outer ring 18.

The first wall surface 52 and the second wall surface 54 are spaced apart from each other in the extension direction of the peripheral wall 50 with the peripheral wall 50 therebetween. The first and second wall surfaces 52, 54 are each approximately perpendicular to the peripheral wall 50. The first wall surface 52 and the second wall surface 54 are parallel to each other.

When the outer ring 18 is mounted in the mounting groove 16, the first outer ring side surface 32 of the outer ring 18 faces the first wall surface 52. The peripheral wall 50 and the outer peripheral surface of the outer ring 18 come into contact with each other.
The multiple first protrusions 46 face the first wall surface 52. The first wall surface 52 is capable of contacting the first outer race side surface 32 of the outer race 18. When the outer race 18 is mounted in the mounting groove 16, the second outer race side surface 34 of the outer race 18 faces the second wall surface 54. The second protrusions 48 face the second wall surface 54. The second wall surface 54 is capable of contacting the second outer race side surface 34 of the outer race 18. The first wall surface 52 and the second wall surface 54 are spaced apart from each other in the axial direction of the central axis of the bearing 12.

The first outer ring side surface 32 contacts the first wall surface 52, the second outer ring side surface 34 contacts the second wall surface 54, and the peripheral wall 50 contacts the outer peripheral surface of the outer ring 18. As a result, the outer ring 18 is held in the mounting groove 16 of the support member 14. Between the first outer ring side surface 32 and the first wall surface 52, there is a first fluid supply section 56 to which the fluid L is supplied. Between the second outer ring side surface 34 and the second wall surface 54, there is a second fluid supply section 58 to which the fluid L is supplied. The fluid L is supplied to the bearing 12 from a fluid supply source (not shown). The fluid L is, for example, a lubricant or coolant such as oil. The fluid L lubricates the inner ring 20 of the bearing 12 when it rotates. At this time, a portion of the fluid L is supplied to the first and second fluid supply sections 56 and 58, respectively.

Next, the operation of the bearing 12 will be explained.

When the rotating shaft 38 rotates due to a driving force from a driving source (not shown), the inner ring 20 of the bearing 12 rotates together with the rotating shaft 38. The rotating direction R of the rotating shaft 38 and the inner ring 20 is the same direction (counterclockwise in FIG. 2, clockwise in FIG. 3). At this time, since the outer ring 18 is fixed to the mounting groove 16 of the support member 14, the outer ring 18 does not rotate with respect to the support member 14. The inner ring 20 rotates relative to the outer ring 18 via the multiple rolling elements 22. In other words, the rotating shaft 38 is rotatably supported by the bearing 12. At this time, a portion of the fluid L is supplied to the first and second fluid supply parts 56, 58 from a fluid supply source (not shown).

As the inner ring 20 rotates, the inner ring 20, the multiple rolling elements 22, and the outer ring 18 heat up, generating heat. The heat generated in the bearing 12 is transferred to the mounting groove 16 of the support member 14 via the first and second outer ring side surfaces 32, 34 and the outer peripheral surface of the outer ring 18. This causes the outer ring 18 of the bearing 12 to thermally expand. The heat transferred from the outer ring 18 causes thermal expansion in the vicinity of the mounting groove 16 of the support member 14.

At this time, the thermal expansion coefficient of the support member 14 is larger than that of the outer ring 18. Therefore, the support member 14 is thermally deformed to a greater extent than the outer ring 18, and as a result, as shown by the two-dot chain line shape in FIG. 4, first and second gaps S1 and S2 are generated between the first and second wall surfaces 52 and 54 of the support member 14 and the first and second outer ring side surfaces 32 and 34 of the outer ring 18, respectively. The first and second gaps S1 and S2 have a predetermined distance in the axial direction of the bearing 12. The first gap S1 is generated in the first fluid supply section 56 to which the fluid L is supplied. The second gap S2 is generated in the second fluid supply section 58 to which the fluid L is supplied. The fitting force between the outer peripheral surface of the outer ring 18 and the peripheral wall 50 is weakened.

The engagement force between the outer peripheral surface of the outer ring 18 and the peripheral wall 50 weakens, and the first and second gaps S1 and S2 are generated, causing the outer ring 18 to be released from the mounting groove 16 of the support member 14 and enter an unfixed state. As a result, the outer ring 18 becomes rotatable together with the inner ring 20 in the rotation direction R (counterclockwise in FIG. 2) as the inner ring 20 rotates. The outer ring 18 rotates while sliding against the mounting groove 16.

When the outer ring 18 starts to rotate in the rotation direction R with the rotation of the inner ring 20, as shown in FIG. 5, in the first fluid supply section 56, the first protrusion 46 moves toward the rotation direction R with the apex 46a at the leading edge. When the first protrusion 46 (first protrusion portion 461) moves in the rotation direction R, the apex 46a pushes the fluid L of the first fluid supply section 56 toward the radial inward and radial outward of the outer ring 18. The fluid L moves from the apex 46a to the bottom portion 46b along each first protrusion 46 of the first protrusion portion 461, so that the fluid L is pushed outward from the first fluid supply section 56. That is, as shown in FIG. 7, the first protrusion 46 pushes the fluid L outward from the first gap S1 between the first outer ring side surface 32 and the first wall surface 52. As a result, the amount of fluid L in the first fluid supply section 56 decreases. That is, the film thickness of the fluid L in the first fluid supply section 56 becomes thinner. The thickness direction of the fluid L in the first gap S1 is the axial direction of the bearing 12.

At this time, the first protrusions 46 move in the rotational direction R of the first fluid supply section 56 shown in FIG. 5, and the movement of the outer ring 18 in the rotational direction R is suppressed by the contact resistance between each of the first protrusions 46 and the fluid L.

As shown in FIG. 6, when the outer ring 18 starts to rotate in the rotation direction R of the inner ring 20 (clockwise in FIG. 6), the second protrusions 48 move in the rotation direction R with the hem 48b at the front in the second fluid supply section 58. When the second protrusions 48 (second protrusions 481) move in the rotation direction R, the hem 48b collects the fluid L of the second fluid supply section 58 along the second protrusions 48 toward the inside of the second protrusions 48. As the fluid L moves from the hem 48b to the apex 48a on the inside of the second protrusions 48, the fluid L around the second protrusions 48 is collected in the second fluid supply section 58 by each second protrusion 48. At this time, as the multiple second protrusions 48 move in the second fluid supply section 58, the movement of the outer ring 18 in the rotation direction R is suppressed by the contact resistance between each second protrusion 48 and the fluid L.

As a result, as shown in FIG. 7, the amount of fluid L in the second fluid supply section 58 increases, generating a dynamic pressure (pressing force) that axially urges the second outer race side surface 34 of the outer race 18 toward the first outer race side surface 32. The pressing force (load) by the fluid L generated in the second fluid supply section 58 causes the second outer race side surface 34 of the outer race 18 to move by being pressed toward the first outer race side surface 32. The first protrusion 46 of the outer race 18 approaches the first wall surface 52 of the support member 14.

That is, when first and second gaps S1, S2 are generated between the mounting groove 16 of the support member 14 and the outer ring 18 due to thermal expansion as the bearing 12 rotates, the multiple second protrusions 48 generate a pressing force in the second fluid supply section 58 (second gap S2) to move the outer ring 18 in the axial direction. This generates a load in the axial direction on the outer ring 18, and by bringing the first outer ring side surface 32 of the outer ring 18 closer to the first wall surface 52 of the mounting groove 16, movement of the outer ring 18 in the rotational direction R relative to the support member 14 is suppressed. Sliding of the outer ring 18 relative to the support member 14 is suppressed.

Next, a bearing structure 80 according to the second embodiment will be described. Note that the same components as those in the bearing structure 10 according to the first embodiment will be given the same reference numerals, and detailed descriptions thereof will be omitted.

As shown in FIG. 8, the bearing structure 80 includes a bearing 82 and a support member 84.

As shown in FIG. 9, the bearing 82 has a rotation suppression protrusion 86 that can suppress the relative rotation of the outer ring 18 with respect to the support member 84. The rotation suppression protrusion 86 has a first protrusion 88 and a second protrusion 90.

As shown in FIG. 10, the first protrusion 88 is disposed on the first outer ring side surface 32 of the outer ring 18 that constitutes the first side surface 26. The apex 46a of the first protrusion 88 is disposed facing counterclockwise in the circumferential direction. The apex 46a of the first protrusion 88 is disposed facing the rotational direction R of the inner ring 20. The bottom portion 46b of the first protrusion 88 is disposed in a position clockwise from the apex 46a in the circumferential direction.

As shown in FIG. 11, the second projection 90 is disposed on the second inner ring side surface 44 of the inner ring 20 that constitutes the second side surface 28. The first projection 88 and the second projection 90 are disposed on opposite sides of each other in the axial direction of the bearing 82. The apex 48a of the second projection 90 is disposed facing in the circumferential direction in a counterclockwise direction. The apex 48a of the second projection 90 is disposed facing in the opposite direction (reverse direction) to the rotational direction R of the inner ring 20.

As shown in FIG. 9, the support member 84 is made of a metal material such as aluminum. The material of the support member 84 has a higher thermal expansion coefficient than the material of the outer ring 18. In other words, the support member 84 is made of a material that has a higher thermal expansion coefficient than the outer ring 18.

The support member 84 has an annular mounting groove 92. The mounting groove 92 faces the outer ring 18 and the inner ring 20 of the bearing 82. The outer ring 18 is fixed to the mounting groove 92. The mounting groove 92 of the support member 84 surrounds the outer ring 18 and the inner ring 20.

The mounting groove 92 has a peripheral wall 50 and a pair of first and second wall surfaces 94, 96. When the bearing 82 is mounted in the mounting groove 92, the first outer race side surface 32 of the outer race 18 and the first inner race side surface 42 of the inner race 20 face the first wall surface 94, respectively. The first protrusion 88 of the first outer race side surface 32 faces the first wall surface 94. The first wall surface 94 can come into contact with the first outer race side surface 32 of the outer race 18.

When the bearing 82 is mounted in the mounting groove 92, the second outer race side surface 34 of the outer race 18 and the second inner race side surface 44 of the inner race 20 face the second wall surface 96, respectively. The second protrusion 90 of the second inner race side surface 44 faces the second wall surface 96. The first outer race side surface 32 contacts the first wall surface 94, the second outer race side surface 34 contacts the second wall surface 96, and the outer peripheral surface of the outer race 18 fits into the peripheral wall 50 of the mounting groove 92, thereby holding the outer race 18 in the mounting groove 92 of the support member 84.

Next, we will explain what happens when the inner ring 20 of the bearing 82 rotates.

When the inner ring 20 rotates together with the rotating shaft 38, the bearing 82 generates heat, causing the inner ring 20 and the outer ring 18 to thermally expand, and the heat transferred from the bearing 82 causes thermal expansion in the vicinity of the mounting groove 92 of the support member 84 (see the two-dot chain line in FIG. 9). As shown in FIG. 9, first and second gaps S1, S2 are generated between the first and second wall surfaces 94, 96 of the support member 84 and the first and second outer ring side surfaces 32, 34 of the outer ring 18. The fitting force between the outer peripheral surface of the outer ring 18 and the peripheral wall 50 of the mounting groove 92 is weakened.

The engagement force between the outer ring 18 and the peripheral wall 50 of the mounting groove 92 weakens, and the first and second gaps S1 and S2 are generated, so that the outer ring 18 is released from the fixed state to the mounting groove 92 of the support member 84 and is in an unfixed state. As a result, the outer ring 18 becomes rotatable together with the inner ring 20 in the rotation direction R (counterclockwise in FIG. 10) as the inner ring 20 rotates.

When the outer ring 18 starts to rotate in the rotation direction R of the inner ring 20, in the first fluid supply section 56, as shown in FIG. 10, the first protrusion 88 moves in the rotation direction R with the apex 46a at the front. When the first protrusion 88 moves in the rotation direction R, the apex 46a pushes the fluid L in the first gap S1 between the first outer ring side surface 32 and the first wall surface 94 radially inward and radially outward of the outer ring 18. The fluid L is pushed outward from the first fluid supply section 56. This reduces the amount of fluid L in the first gap S1.

As the inner ring 20 rotates in the rotational direction R, as shown in FIG. 12, the second protrusion 90 arranged on the inner ring 20 moves in the rotational direction R with the bottom 48b at the front. When the second protrusion 90 moves in the rotational direction R, the bottom 48b collects the fluid L between the second inner ring side surface 44 and the second wall surface 96 along the second protrusion 90 toward the inside of the second protrusion 90. The amount of fluid L between the second inner ring side surface 44 and the second wall surface 96 shown in FIG. 13 increases, and a dynamic pressure (pressing force) is generated that urges the second inner ring side surface 44 of the inner ring 20 in the axial direction toward the first inner ring side surface 42. The pressing force of the fluid L presses the second inner ring side surface 44 of the inner ring 20 toward the first inner ring side surface 42, and the inner ring 20 moves.

When the second inner ring side surface 44 of the inner ring 20 moves axially toward the first inner ring side surface 42 (first wall surface 52), the multiple rolling elements 22 move axially toward the first wall surface 94 together with the inner ring 20. As the multiple rolling elements 22 move, the outer ring 18 moves axially toward the first wall surface 94 together with the rolling elements 22. As shown in FIG. 13, the first protrusion 88 of the outer ring 18 approaches the first wall surface 94 of the support member 84.

As a result, when the first and second gaps S1, S2 are generated between the mounting groove 92 of the support member 84 and the outer ring 18 due to thermal expansion as the bearing 82 rotates, the second protrusion 90 (rotation suppression protrusion 86) of the inner ring 20 generates a pressing force between the second wall surface 96 and the second inner ring side surface 44, moving the inner ring 20 toward the first wall surface 52 of the support member 84, and pressing the outer ring 18 toward the first wall surface 52 via the inner ring 20 and the rolling elements 22. This generates a load in the axial direction on the outer ring 18, and by bringing the first outer ring side surface 32 closer to the first wall surface 94 of the mounting groove 92, movement of the outer ring 18 in the rotation direction R relative to the support member 84 is suppressed. Sliding of the outer ring 18 against the support member 84 is suppressed.

Alternatively, the first protrusion 88 may be disposed on the first inner ring side surface 42 of the inner ring 20, and the second protrusion 90 may be disposed on the second outer ring side surface 34 of the outer ring 18.

As described above, in the embodiment of the present invention, when the bearings 12, 82 and the support members 14, 84 thermally expand due to the rotation of the inner ring 20 to generate the first and second gaps S1, S2, the fluid L of the first and second fluid supply units 56, 58 can be used to generate dynamic pressure in the axial direction of the bearings 12, 82 by the rotation suppression protrusions 24, 86. This allows a load to be generated in the thrust direction (axial direction) on the bearings 12, 82 and the relative rotation of the outer ring 18 supported by the support members 14, 84 to be suppressed with a simple configuration in which the rotation suppression protrusions 24, 86 are provided on at least one of the first and second side surfaces 26, 28 of the bearings 12, 82. As a result, compared to a configuration in which a recess and a high thermal expansion member are provided in the bearings, it is possible to reduce the number of parts, manufacturing costs, and manufacturing man-hours of the bearings 12, 82, while suppressing the relative rotation of the bearings 12, 82, thereby improving the durability of the bearings 12, 82 and the support members 14, 84.

By arranging the rotation suppression protrusions 24 on the first outer ring side surface 32 and the second outer ring side surface 34 of the outer ring 18, dynamic pressure can be generated between the first and second outer ring side surfaces 32, 34 of the outer ring 18 and the first and second wall surfaces 52, 54 of the support member 14, respectively. This makes it possible to effectively suppress the relative rotation of the outer ring 18 with respect to the support member 14 by moving the outer ring 18 axially using dynamic pressure.

By arranging the apex 46a of the rotation suppression protrusion 24 facing the rotation direction R of the inner ring 20, the fluid L in the first gap S1 (first fluid supply section 56) can be pushed aside by the rotation suppression protrusion 24. This makes it possible to reduce the pressure of the fluid L in the first gap S1.

The rotation suppression protrusion 24 has a first protrusion 46 arranged on the first outer ring side surface 32 of the outer ring 18 and a second protrusion 48 arranged on the second outer ring side surface 34, so that the first and second protrusions 46, 48 can generate dynamic pressure on the first and second outer ring side surfaces 32, 34 sides of the outer ring 18, respectively. This makes it possible to more effectively suppress the relative rotation of the outer ring 18 with respect to the support member 14.

In the bearing 12, the apex 46a of the first protrusion 46 is arranged to face the rotation direction R of the inner ring 20, and the apex 48a of the second protrusion 48 is arranged to face the opposite direction to the rotation direction R of the inner ring 20. Therefore, the first protrusion 46 reduces the pressure in the first gap S1 facing the first outer ring side surface 32, and the second protrusion 48 collects the fluid L in the second gap S2 toward the apex 48a, thereby increasing the pressure in the second gap S2. As a result, a pressing force acts on the bearing 12 in the direction from the second outer ring side surface 34 to the first outer ring side surface 32, effectively suppressing the relative rotation of the outer ring 18 with respect to the support member 14.

The rotation suppression protrusion 24 has a first protrusion 46 arranged on the first outer ring side surface 32 of the outer ring 18 and a second protrusion 48 arranged on the second inner ring side surface 44 of the inner ring 20, so that dynamic pressure can be generated on both sides in the axial direction of the bearing 12 via the inner ring 20 and the outer ring 18. This makes it possible to effectively suppress the relative rotation of the outer ring 18 with respect to the support member 14.

In the bearing 82, the apex 46a of the first protrusion 88 arranged on the outer ring 18 is arranged to face the rotation direction R of the inner ring 20, and the apex 48a of the second protrusion 90 arranged on the inner ring 20 is arranged to face the opposite direction to the rotation direction R of the inner ring 20. As a result, the first protrusion 88 reduces the pressure in the first gap S1 of the bearing 82, and the second protrusion 90 increases the pressure in the second gap S2 of the bearing 82. As a result, a pressing force acts on the bearing 82 in the direction from the second outer ring side surface 34 to the first outer ring side surface 32, effectively suppressing the relative rotation of the outer ring 18 with respect to the support member 84.

The first protrusions 46, 88 and the second protrusions 48, 90 of the rotation suppression protrusions 24, 86 are printed on the first and second side surfaces 26, 28, respectively, so that the first protrusions 46, 88 and the second protrusions 48, 90 can be easily formed on the first and second side surfaces 26, 28 of the bearings 12, 82.

The above embodiments can be summarized as follows:

The above embodiment includes a bearing (12, 82) having an outer ring (18), an inner ring (20) arranged inside the outer ring and rotatable relative to the outer ring, and a plurality of rolling elements (22) arranged between the inner ring and the outer ring;
a support member (14, 84) formed of a material having a thermal expansion coefficient larger than that of the outer ring and to which the outer ring is fixed, the bearing having an annular first side surface (26) facing one side in the axial direction of the bearing and an annular second side surface (28) facing the other side in the axial direction,
The bearing has a rotation suppression projection (24, 86) projecting in the axial direction from at least one of the first side surface and the second side surface,
The rotation suppression projection is formed in a V-shape having vertices (46a, 48a) facing in the circumferential direction of the bearing,
The support member has a wall surface (52, 54, 94, 96) that faces the rotation inhibiting protrusion in the axial direction, and when the inner ring rotates, a fluid (L) is supplied between the side surface on which the rotation inhibiting protrusion is located and the wall surface.

The outer ring has an annular first outer ring side surface (32) that is a part of the first side surface and an annular second outer ring side surface (34) that is a part of the second side surface,
The rotation inhibiting projection is disposed on at least one of the first outer ring side surface and the second outer ring side surface.

The apex (46a) of the rotation suppression protrusion faces the rotation direction (R) of the inner ring.

The rotation suppression protrusion has a first protrusion (46) arranged on the first outer ring side surface and a second protrusion (48) arranged on the second outer ring side surface.

The apex of the first projection faces a rotation direction of the inner ring,
The apex of the second projection faces in a direction opposite to a rotation direction of the inner ring.

the outer ring has an annular first outer ring side surface that is a part of the first side surface and an annular second outer ring side surface that is a part of the second side surface,
The inner ring has an annular first inner ring side surface (42) which is another part of the first side surface, and an annular second inner ring side surface (44) which is another part of the second side surface,
The rotation suppressing projection has a first projection (88) disposed on the first outer ring side surface and a second projection (90) disposed on the second inner ring side surface.

The apex of the first projection faces a rotation direction of the inner ring,
The apex of the second projection faces in a direction opposite to a rotation direction of the inner ring.

The rotation suppression protrusion is a printed material printed on the side surface.

The present invention is not limited to the above disclosure, and various configurations may be adopted without departing from the gist of the present invention.

10, 80... Bearing structure 12, 82... Bearing 14, 84... Support member 18... Outer ring 20... Inner ring 22... Rolling element 24, 86... Rotation suppressing protrusion 26... First side surface 28... Second side surface 46a, 48a... Apex 52, 94... First wall surface 54, 96... Second wall surface

Claims (8)

a bearing including an outer ring, an inner ring disposed inside the outer ring and rotatable relative to the outer ring, and a plurality of rolling elements disposed between the inner ring and the outer ring;
a support member to which the outer ring is fixed, the support member being formed of a material having a larger thermal expansion coefficient than the outer ring, the bearing having an annular first side surface facing one side in an axial direction of the bearing and an annular second side surface facing the other side in the axial direction,
The bearing has a rotation suppression protrusion protruding in the axial direction from at least one of the first side surface and the second side surface,
The rotation suppression projection is formed in a V-shape having an apex facing in a circumferential direction of the bearing,
A bearing structure wherein the support member has a wall surface facing the rotation inhibiting protrusion in the axial direction, and when the inner ring rotates, a fluid is supplied between the side surface on which the rotation inhibiting protrusion is arranged and the wall surface. 2. The bearing structure according to claim 1,
the outer ring has an annular first outer ring side surface that is a part of the first side surface and an annular second outer ring side surface that is a part of the second side surface,
A bearing structure, wherein the rotation suppression protrusion is disposed on at least one of the first outer ring side surface and the second outer ring side surface. 3. The bearing structure according to claim 2,
A bearing structure, wherein the apex of the rotation suppressing protrusion faces in a rotation direction of the inner ring. 3. The bearing structure according to claim 2,
A bearing structure, wherein the rotation suppressing protrusion has a first protrusion arranged on the first outer ring side surface and a second protrusion arranged on the second outer ring side surface. 5. The bearing structure according to claim 4,
The apex of the first projection faces a rotation direction of the inner ring,
a bearing structure, wherein the apex of the second protrusion faces in a direction opposite to a rotation direction of the inner ring. 2. The bearing structure according to claim 1,
the outer ring has an annular first outer ring side surface that is a part of the first side surface and an annular second outer ring side surface that is a part of the second side surface,
the inner ring has an annular first inner ring side surface that is another part of the first side surface and an annular second inner ring side surface that is another part of the second side surface,
A bearing structure, wherein the rotation inhibiting protrusion has a first protrusion arranged on the first outer ring side surface and a second protrusion arranged on the second inner ring side surface. 7. The bearing structure according to claim 6,
The apex of the first projection faces a rotation direction of the inner ring,
a bearing structure, wherein the apex of the second protrusion faces in a direction opposite to a rotation direction of the inner ring. The bearing structure according to any one of claims 1 to 7,
A bearing structure, wherein the rotation suppressing protrusion is a printed body printed on the side surface.

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