阅读说明：本技术 轴承装置以及旋转装置 (Bearing device and rotating device ) 是由 长井直之 荒川卓哉 二江贵也 三浦秀一 段本洋辅 杉山晓洋 于 2019-03-22 设计创作，主要内容包括：一实施方式的轴承装置是用于将旋转轴支承为能够旋转的轴承装置,其中,所述轴承装置具备：至少一个滚动轴承,所述至少一个滚动轴承包括内圈、滚动体及外圈,所述内圈固定于所述旋转轴,在所述外圈与所述内圈之间将所述滚动体保持为能够旋转；以及壳体,所述壳体收纳所述滚动轴承,所述壳体在周向上隔开间隔地形成有用于向所述滚动轴承与所述壳体的内周面之间的第一间隙供给润滑油的多个第一供油孔,在将所述第一供油孔的出口开口的直径设为d-(1),将所述第一间隙的间隔设为δ-(1)的情况下,所述多个第一供油孔分别满足下述(a)式：π·d-(1)·δ-(1)<π·d-(1)～(2)/4 (a)。(A bearing device according to an embodiment is a bearing device for rotatably supporting a rotating shaft, the bearing device including: at least one rolling bearing including an inner ring, a rolling body, and an outer ring, the inner ring being fixed to the rotating shaft, the rolling body being held rotatably between the outer ring and the inner ring; and a housing that houses the rolling bearing, the housing having a plurality of first oil supply holes formed at intervals in a circumferential direction for supplying a lubricating oil to a first gap between the rolling bearing and an inner circumferential surface of the housing, and the diameter of an outlet opening of the first oil supply hole is defined as d 1 Setting the interval of the first gap to delta 1 In the case of (a), the plurality of first oil supply holes satisfy the following expression: pi. d 1 ·δ 1 <π·d 1 2 /4 (a)。)

1. A bearing device for rotatably supporting a rotary shaft, the bearing device comprising:

at least one rolling bearing including an inner ring, a rolling body, and an outer ring, the inner ring being fixed to the rotating shaft, the rolling body being held rotatably between the outer ring and the inner ring; and

a housing that houses the rolling bearing, the housing having a plurality of first oil supply holes formed at intervals in a circumferential direction for supplying lubricating oil to a first gap between the rolling bearing and an inner circumferential surface of the housing,

d represents a diameter of an outlet opening of the first oil supply hole₁Setting the interval of the first gap to delta₁In the case of (a) in (b),

the plurality of first oil supply holes satisfy the following expressions (a) respectively:

π·d₁·δ₁<π·d₁ ²/4 (a)。

2. the bearing device of claim 1,

the plurality of first oil supply holes are arranged symmetrically with respect to an axial center of the rotating shaft in a cross section of the rotating shaft.

3. Bearing device according to claim 1 or 2,

a first recess is formed in an opposing surface of the housing that faces the inner peripheral surface of the housing with the first gap therebetween, and a cross-sectional area of the first recess in a direction perpendicular to an axis of the rotary shaft decreases from a position where the cross-sectional area is largest toward at least one side in an axial direction.

4. The bearing device of claim 3,

the first recess is configured such that a depth thereof becomes smaller toward the one side in the axial direction.

5. Bearing device according to claim 3 or 4,

the first recess is configured such that the cross-sectional area decreases from the position where the cross-sectional area is largest toward the one side and the other side in the axial direction, and a distance from the position where the cross-sectional area is largest to an end portion on the one side in the axial direction is equal to a distance from the position where the cross-sectional area is largest to an end portion on the other side in the axial direction.

6. The bearing device according to any one of claims 3 to 5,

the first recess is configured such that the position where the cross-sectional area is largest faces the outlet opening of the first oil supply hole.

7. The bearing device according to any one of claims 3 to 6,

the at least one rolling bearing includes a plurality of rolling bearings arranged at intervals in an axial direction of the rotating shaft,

the bearing device further includes a cover member configured to cover the outer peripheries of the plurality of rolling bearings,

the facing surface is formed by an outer peripheral surface of the cover member.

8. The bearing device as claimed in claim 7,

a second oil supply hole for supplying a lubricating oil to a second gap between one end surface of the cover member in the axial direction and the inner surface of the housing, and a third oil supply hole for supplying a lubricating oil to a third gap between the other end surface of the cover member in the axial direction and the inner surface of the housing,

d represents a diameter of an outlet opening of the second oil supply hole₂Setting the interval of the second gap to delta₂，

D represents a diameter of an outlet opening of the third oil supply hole₃Setting the interval of the third gap to delta₃In the case of (a) in (b),

the first oil supply holes satisfy the following expressions (b) and (c), respectively:

π·d₂·δ₂<π·d₂ ²/4 (b)

π·d₃·δ₃<π·d₃ ²/4 (c)。

9. the bearing device of claim 8,

a second recess portion is formed in the one end surface in the axial direction facing the inner side surface of the housing with the second gap therebetween, the second recess portion being configured such that a cross-sectional area in a direction parallel to the axis of the rotary shaft decreases from a position where the cross-sectional area is largest toward at least one side in a radial direction,

a third recess is formed in the other end surface of the housing in the axial direction facing the inner surface of the housing with the third gap therebetween, and the third recess is configured such that a cross-sectional area in a direction parallel to the axis of the rotary shaft decreases from a position where the cross-sectional area is largest toward at least one side in a radial direction.

10. A bearing device for rotatably supporting a rotary shaft, the bearing device comprising:

a plurality of rolling bearings including an inner ring fixed to the rotating shaft, a rolling element, and an outer ring, the rolling element being rotatably held between the outer ring and the inner ring, the plurality of rolling bearings being arranged at intervals in an axial direction of the rotating shaft;

a cover member configured to cover outer peripheries of the plurality of rolling bearings; and

a housing that houses the plurality of rolling bearings and the cover member, the housing being formed with a second oil supply hole for supplying lubricating oil to a second gap between one end surface in the axial direction of the cover member and an inner surface of the housing, and a third oil supply hole for supplying lubricating oil to a third gap between the other end surface in the axial direction of the cover member and the inner surface of the housing,

d represents a diameter of an outlet opening of the second oil supply hole₂Setting the interval of the second gap to delta₂，

D represents a diameter of an outlet opening of the third oil supply hole₃Setting the interval of the third gap to delta₃In the case of (a) in (b),

the second oil supply hole satisfies the following expression (b), and the third oil supply hole satisfies the following expression (c):

π·d₂·δ₂<π·d₂ ²/4 (b)

π·d₃·δ₃<π·d₃ ²/4 (c)。

11. the bearing device of claim 10,

a second recess portion is formed in the one end surface in the axial direction facing the inner side surface of the housing with the second gap therebetween, the second recess portion being configured such that a cross-sectional area in a direction parallel to the axis of the rotary shaft decreases from a position where the cross-sectional area is largest toward at least one side in a radial direction,

a third recess is formed in the other end surface of the housing in the axial direction facing the inner surface of the housing with the third gap therebetween, and the third recess is configured such that a cross-sectional area in a direction parallel to the axis of the rotary shaft decreases from a position where the cross-sectional area is largest toward at least one side in a radial direction.

12. A rotating device, comprising:

a rotating shaft; and

a bearing arrangement according to any one of claims 1 to 11.

Technical Field

The present disclosure relates to a bearing device and a rotating device.

Background

In a rotating device such as a turbocharger, when a rotating shaft is supported by a rolling bearing, a contact portion between a rotating portion and a stationary portion of the rolling bearing is in metal contact, and therefore, vibration damping capability is poor. Therefore, the rolling bearing has high vibration sensitivity during high-speed rotation or due to disturbance, and is likely to cause breakage, abnormal noise, and the like. Patent document 1 discloses a vibration suppressing member including: an oil film is formed in a gap between an outer ring of a rolling bearing that supports a rotating shaft of a pump and a housing that houses the rolling bearing, and the oil film has a damping effect due to a squeezing action of the oil film.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2004-339986

Disclosure of Invention

Problems to be solved by the invention

If the oil film is not formed properly, the vibration suppressing member based on the squeezing action of the oil film cannot exhibit the vibration damping effect. Therefore, it is necessary to position the outer ring relative to the housing at a position where an oil film can be formed. The proposal disclosed in patent document 1 is a simple structure in which oil is simply injected only into the gap between the outer ring of the rolling bearing and the housing, but the vibration damping effect is considered to be small because there is no positioning mechanism for the rolling bearing for forming an oil film. When a positioning member such as an O-ring or a metal spring is used as a mechanical positioning mechanism of a rolling bearing, the mechanical positioning member needs to have rigidity lower than that of the rolling bearing by one digit or more in order to exhibit a vibration damping action by an oil film. However, the rubber O-ring is poor in durability, while the metal spring has high rigidity, and is prone to fatigue failure when used in a high-temperature environment such as a turbocharger.

An object of one embodiment of the present disclosure is to provide a bearing device capable of forming a good oil film in a gap between an outer ring of a rolling bearing and a housing without using a mechanical member when supporting a rotating shaft by the rolling bearing.

Means for solving the problems

(1) A bearing device according to an embodiment is a bearing device for rotatably supporting a rotating shaft, the bearing device including:

at least one rolling bearing including an inner ring, a rolling body, and an outer ring, the inner ring being fixed to the rotating shaft, the rolling body being held rotatably between the outer ring and the inner ring; and

a housing that houses the rolling bearing, the housing having a plurality of first oil supply holes formed at intervals in a circumferential direction for supplying lubricating oil to a first gap between the rolling bearing and an inner circumferential surface of the housing,

d represents a diameter of an outlet opening of the first oil supply hole₁Setting the interval of the first gap to delta₁In the case of (a) in (b),

the plurality of first oil supply holes satisfy the following expressions (a) respectively:

π·d₁·δ₁<π·d₁ ²/4 (a)。

according to the configuration of the above (1), since the first clearance satisfies the above expression (a), so-called self-controlled throttling (japanese patent application No. り) in which the oil film exerts a squeezing action is constituted, and therefore, a good oil film can be formed in the clearance between the outer ring of the rolling bearing and the housing without using a mechanical member. When the rotating shaft is eccentric by vibration, the pressure loss at the side where the first gap is narrowed becomes large and high pressure is generated, and therefore, a force in the direction opposite to the eccentric direction acts on the rotating shaft, and the rotating shaft returns to the stationary position before the eccentricity. Thus, the oil film can be held in the first gap, and the vibration of the rotating shaft can be damped even if the rotating shaft vibrates.

(2) In one embodiment, in the structure of the above (1),

the plurality of first oil supply holes are arranged symmetrically with respect to an axis of the rotating shaft in a cross section of the rotating shaft.

According to the configuration of the above (2), since the plurality of first oil supply holes are arranged symmetrically with respect to the axial center of the rotating shaft, the lubricating oil can be supplied uniformly to the first gap in the circumferential direction of the rotating shaft. This enables a favorable oil film to be formed in the first gap.

(3) In one embodiment, in the structure of the above (1) or (2),

a first recess is formed in an opposing surface of the housing that faces the inner peripheral surface of the housing with the first gap therebetween, and a cross-sectional area of the first recess in a direction perpendicular to an axis of the rotary shaft decreases from a position where the cross-sectional area is largest toward at least one side in an axial direction.

According to the configuration of the above (3), the lubricating oil supplied from the first oil supply hole to the first recessed portion is accelerated in the axial direction of the rotating shaft (hereinafter also simply referred to as "axial direction") along the surface of the first recessed portion, and a perpendicular component force is generated with respect to the surface of the first recessed portion by the dynamic pressure of the lubricating oil. This vertical component force acts to return the eccentric rotation shaft to a stationary position. Therefore, in the present embodiment, the self-control throttling effect on the oil film and the centering effect in the radial direction of the rotating shaft (radial direction of the rotating shaft) by the dynamic pressure of the lubricating oil can be achieved at the same time. This can keep the oil film in the first gap and suppress radial vibration of the rotating shaft.

(4) In one embodiment, in the structure of the above (3),

the first recess is configured such that a depth thereof becomes smaller toward the one side in the axial direction.

According to the configuration of the above (4), the lubricating oil supplied from the first oil supply hole to the first concave portion is accelerated in the axial direction of the rotating shaft, and therefore, the self-control throttling effect of the oil film and the centering effect in the radial direction of the rotating shaft by the dynamic pressure of the lubricating oil can be further improved.

(5) In one embodiment, in the structure of the above (3) or (4),

the first recess is configured such that the cross-sectional area decreases from the position where the cross-sectional area is largest toward the one side and the other side in the axial direction, and a distance from the position where the cross-sectional area is largest to an end portion on the one side in the axial direction is equal to a distance from the position where the cross-sectional area is largest to an end portion on the other side in the axial direction.

In the configuration of the above (5), when the lubricant is supplied to the first recess portion, the lubricant is branched on the surface of the first recess portion toward one and the other in the axial direction. Therefore, a force for moving the rotational shaft to one side or the other side can be generated depending on the position of the lubricant oil supply. For example, when the lubricant is supplied to the position where the cross-sectional area is the largest, the distribution of the vertical component force generated on the surface of the first concave portion along the axial direction is symmetrical with the position where the cross-sectional area is the largest as the center. Therefore, when the rotating shaft moves from the stationary position to the axial direction due to vibration or the like, the distribution of the vertical component force generated on the surface of the first concave portion along the axial direction becomes asymmetric. Therefore, the dynamic pressure of the lubricating oil acting on the surface of the first recess in the direction opposite to the moving direction of the rotating shaft increases, and a force for returning the rotating shaft to the original stationary position is applied. According to this embodiment, the self-aligning effect in the thrust direction (axial direction of the rotating shaft) can be exhibited in addition to the self-aligning effect of the oil film and the radial aligning effect by the dynamic pressure of the lubricating oil.

(6) In one embodiment, in any of the structures (3) to (5) above,

the first recess is configured such that the position where the cross-sectional area is largest faces the outlet opening of the first oil supply hole.

In the configuration of the above (6), when the rotary shaft is located at the stationary position, the lubricant oil discharged from the outlet opening of the first oil supply hole is supplied to the position where the cross-sectional area of the first concave portion is maximized, and therefore, the kinetic energy of the lubricant oil can be efficiently converted into the dynamic pressure acting on the surface of the first concave portion.

(7) In one embodiment, in any of the structures (3) to (6) above,

the at least one rolling bearing includes a plurality of rolling bearings arranged at intervals in an axial direction of the rotating shaft,

the bearing device further includes a cover member configured to cover the outer peripheries of the plurality of rolling bearings,

the facing surface is formed by an outer peripheral surface of the cover member.

According to the configuration of the above (7), since the cover member is provided and the first recess is formed in the outer peripheral surface of the cover member, the dynamic pressure of the lubricating oil is transmitted to the rolling bearing via the cover member. Therefore, a uniform force acts on each of the plurality of rolling bearings from the cover member, and the rolling bearings are collectively operated by the cover member, so that the centering effect with respect to the rotating shaft can be improved.

(8) In one embodiment, in the structure of the above (7),

a second oil supply hole for supplying a lubricating oil to a second gap between one end surface of the cover member in the axial direction and the inner surface of the housing, and a third oil supply hole for supplying a lubricating oil to a third gap between the other end surface of the cover member in the axial direction and the inner surface of the housing,

d represents a diameter of an outlet opening of the second oil supply hole₂Setting the interval of the second gap to delta₂，

D represents a diameter of an outlet opening of the third oil supply hole₃Setting the interval of the third gap to delta₃In the case of (a) in (b),

the first oil supply holes satisfy the following expressions (b) and (c), respectively:

π·d₂·δ₂<π·d₂ ²/4 (b)

π·d₃·δ₃<π·d₃ ²/4 (c)。

according to the configuration of the above (8), since the self-control throttle by the squeezing action of the oil film is formed when the lubricating oil supplied from the second oil supply hole and the third oil supply hole passes through the second gap and the third gap, a good oil film can be formed in the second gap and the third gap without using a mechanical member, and also when the rotating shaft moves from the static position to one or the other of the thrust directions due to vibration, the vibration in the thrust direction can be damped, and the centering effect of returning to the original static position can be exhibited. Therefore, it is possible to achieve both the radial aligning effect by the self-controlled throttling of the lubricating oil supplied from the first oil supply hole and the thrust direction aligning effect by the self-controlled throttling of the lubricating oil supplied from the second oil supply hole and the third oil supply hole.

(9) In one embodiment, in the structure of the above (8),

a second recess portion is formed in the one end surface in the axial direction facing the inner side surface of the housing with the second gap therebetween, the second recess portion being configured such that a cross-sectional area in a direction parallel to the axis of the rotary shaft decreases from a position where the cross-sectional area is largest toward at least one side in a radial direction,

a third recess is formed in the other end surface of the housing in the axial direction facing the inner surface of the housing with the third gap therebetween, and the third recess is configured such that a cross-sectional area in a direction parallel to the axis of the rotary shaft decreases from a position where the cross-sectional area is largest toward at least one side in a radial direction.

According to the structure of the above (9), the lubricating oil supplied from the second oil supply hole to the second recess portion is accelerated in the radial direction, and therefore, a vertical component force is generated on the surface of the second recess portion by the dynamic pressure of the lubricating oil. The vertical component force is a force for returning the rotating shaft moving in the thrust direction to the stationary position. The same vertical component force acts on the lubricating oil supplied from the third oil supply hole to the third recess. Therefore, in the present embodiment, the self-control throttling effect of the oil film and the centering effect in the radial direction of the rotating shaft by the dynamic pressure of the lubricating oil can be achieved at the same time. This can exhibit a vibration damping effect even when vibration occurs in the radial direction on the rotating shaft. Therefore, it is possible to achieve both the self-control throttling effect on the oil film supplied from the first oil supply hole and the radial aligning effect by the first concave portion, and the self-control throttling effect on the oil film supplied from the second oil supply hole and the third oil supply hole and the aligning effect in the thrust direction by the second concave portion and the third concave portion.

(10) A bearing device according to an embodiment is a bearing device for rotatably supporting a rotating shaft, the bearing device including:

a plurality of rolling bearings including an inner ring fixed to the rotating shaft, a rolling element, and an outer ring, the rolling element being rotatably held between the outer ring and the inner ring, the plurality of rolling bearings being arranged at intervals in an axial direction of the rotating shaft;

a cover member configured to cover outer peripheries of the plurality of rolling bearings; and

a housing that houses the plurality of rolling bearings and the cover member, the housing being formed with a second oil supply hole for supplying lubricating oil to a second gap between one end surface in the axial direction of the cover member and an inner surface of the housing, and a third oil supply hole for supplying lubricating oil to a third gap between the other end surface in the axial direction of the cover member and the inner surface of the housing,

d represents a diameter of an outlet opening of the second oil supply hole₂Setting the interval of the second gap to delta₂，

D represents a diameter of an outlet opening of the third oil supply hole₃Setting the interval of the third gap to delta₃In the case of (a) in (b),

the second oil supply hole satisfies the following expression (b), and the third oil supply hole satisfies the following expression (c):

π·d₂·δ₂<π·d₂ ²/4 (b)

π·d₃·δ₃<π·d₃ ²/4 (c)。

according to the configuration of the above (10), since the so-called self-control throttling by the squeezing action of the oil film is configured when the lubricating oil supplied from the second oil supply hole and the third oil supply hole passes through the second gap and the third gap, it is possible to form a good oil film in the second gap and the third gap without using a mechanical member, and also, when the rotating shaft moves from the static position to one or the other of the thrust directions due to vibration, it is possible to damp the vibration in the thrust direction, and it is possible to exert the centering effect of returning to the original static position.

(11) In one embodiment, in the structure of the above (10),

a second recess portion is formed in the one end surface in the axial direction facing the inner side surface of the housing with the second gap therebetween, the second recess portion being configured such that a cross-sectional area in a direction parallel to the axis of the rotary shaft decreases from a position where the cross-sectional area is largest toward at least one side in a radial direction,

a third recess is formed in the other end surface of the housing in the axial direction facing the inner surface of the housing with the third gap therebetween, and the third recess is configured such that a cross-sectional area in a direction parallel to the axis of the rotary shaft decreases from a position where the cross-sectional area is largest toward at least one side in a radial direction.

According to the structure of the above (11), the lubricating oil supplied from the second oil supply hole to the second recess portion is accelerated in the radial direction, and therefore, a vertical component force is generated on the surface of the second recess portion by the dynamic pressure of the lubricating oil. The vertical component force is a force for returning the rotating shaft moving in the thrust direction to the stationary position. When the lubricating oil is supplied from the third oil supply hole to the third recess, the same vertical component force acts. Therefore, the self-control throttling effect on the oil film and the radial aligning effect of the rotating shaft caused by the dynamic pressure of the lubricating oil can be achieved at the same time. Therefore, even if vibration occurs in the radial direction at the rotating shaft, the vibration damping effect can be exhibited. In this way, the thrust bearing provided in the rotary shaft can be eliminated, depending on the situation.

(12) A rotating device of an embodiment comprises:

a rotating shaft; and

a bearing device having any one of the configurations (1) to (11) described above.

According to the structure of the above (12), since the bearing device having the above structure is provided, the self-control throttle by the squeezing action of the lubricating oil film is formed in the gap between the housing accommodating the rolling bearing and the rolling bearing, and therefore, a good oil film can be formed in the gap between the outer ring of the rolling bearing and the housing without using a mechanical member. Therefore, even if the rotating shaft vibrates, the vibration of the rotating shaft can be damped.

ADVANTAGEOUS EFFECTS OF INVENTION

According to some embodiments, a good oil film can be formed without using a mechanical member by self-control throttling of a gap between an outer ring of a rolling bearing and a housing by using a lubricating oil. This can suppress vibration of the rotating shaft.

Drawings

Fig. 1 is a longitudinal sectional view of a rotating device including a bearing device according to an embodiment.

Fig. 2 is a longitudinal sectional view of a bearing device according to an embodiment.

Fig. 3 is a schematic diagram showing a supply system for supplying lubricating oil to the bearing device.

Fig. 4 is an explanatory diagram for explaining the restoring force of the rotating shaft by the squeezing action of the oil film.

Fig. 5 is an enlarged view of a portion a in fig. 2.

Fig. 6 is a sectional view of a bearing device according to an embodiment.

Fig. 7 is a longitudinal sectional view of a bearing device according to an embodiment.

Fig. 8 is a longitudinal sectional view of a bearing device according to an embodiment.

Fig. 9 is a longitudinal sectional view of a bearing device according to an embodiment.

Detailed Description

Hereinafter, several embodiments of the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention, and are merely illustrative examples.

For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "central", "concentric", or "coaxial" indicate relative or absolute arrangements, and indicate not only arrangements as described above but also a state of relative displacement with a tolerance or an angle or a distance to such an extent that the same function can be obtained.

For example, the expression "square or cylindrical" indicates not only a shape such as a square or cylindrical shape in a strict geometrical sense but also a shape including a concave-convex portion, a chamfered portion, and the like within a range in which the same effect can be obtained.

On the other hand, the expression "provided with", "equipped with", "provided with", "including" or "having" one structural element is not an exclusive expression excluding the presence of other structural elements.

Fig. 1 is a vertical sectional view of a rotating device 50 including a bearing device 10 relating to a bearing device, and fig. 2 is a vertical sectional view of the bearing device 10(10A) according to an embodiment. The bearing device 10(10A) is provided with a shaft axis O for supporting the rotating shaft 12₁At least one rolling bearing 14 rotatable about a center thereof, the rolling bearing 14 being housed in the case 16. The rolling bearing 14 is composed of an inner ring 18 fixed to the rotating shaft 12, rolling elements 20, and an outer ring 22 rotatably holding the rolling elements 20 with the inner ring 18. A plurality of oil supply holes 24(24a, 24b, 24C, 26d) (first oil supply holes) are formed in the housing 16 at intervals in the circumferential direction, and a gap C formed between the rolling bearing 14 and the inner surface 16a of the housing 16 is provided through the plurality of oil supply holes 24(24a to 24d)₁The (first gap) is supplied with the high-pressure lubricating oil r. D represents the diameter of the outlet opening of the oil supply hole 24₁Will be spaced apart by a distance C₁Is set to be delta₁In this case, each oil supply hole 24 satisfies the following expression (a).

π·d₁·δ₁<π·d₁ ²/4 (a)

FIG. 3 shows a lubricating oil supply system including a rotary shaft 12 and a rolling bearingFig. 14 is a schematic diagram of one structure (12+ 14). In one embodiment, the plurality of oil supply holes 24(24a to 24d) are formed in the cross section of the rotary shaft 12 with respect to the axis O of the rotary shaft 12₁Are symmetrically arranged. According to this embodiment, the plurality of oil supply holes 24(24a to 24d) are formed with respect to the axis O of the rotary shaft 12₁Are symmetrically arranged, so that the gap C can be formed in the circumferential direction of the rotating shaft 12₁The lubricating oil r is supplied uniformly. Thereby, the gap C can be formed₁A good oil film is formed. For example, when the bearing device 10(10A) is applied to a small-sized rotating device such as a turbocharger, the plurality of oil supply holes 24(24a to 24d) are formed with respect to the axis O of the rotating shaft 12₁Symmetrically arranged so as to be able to form a gap C in the circumferential direction of the rotating shaft 12₁Supplying the lubricating oil at the same pressure. Thereby, the gap C can be formed₁A uniform oil film is formed along the circumferential direction of the rotating shaft 12.

In one embodiment, as shown in fig. 3, the plurality of oil supply holes 24 are arranged at equal intervals in the circumferential direction of the casing 16, for example. The plurality of oil supply holes 24 are provided 3 at intervals of 120 ° or 4 at intervals of 90 °, so that the supply amount of the lubricating oil is uniformly distributed in the circumferential direction of the rolling bearing 14. The plurality of oil supply holes 24 are arranged in a direction perpendicular to the outer circumferential surface and the inner circumferential surface of the housing 16.

As in the above-described embodiment, in the clearance C₁In the case of the self-controlled throttling, the outlet opening of the oil supply hole 24 is formed to be the same as or smaller than the cross-sectional area of the oil supply hole 24 on the upstream side.

The bearing device 10(10B, 10C) according to the other embodiment shown in fig. 7 and 8 also has the above-described structure of the bearing device 10(10A) described above in common. Therefore, in fig. 7 and 8, the same components and the same devices as those of the bearing device 10(10A) are denoted by the same reference numerals.

FIG. 4 is a schematic view showing a clearance C formed between the rolling bearing 14 and the housing 16₁The figure (a). A clearance C satisfying the above formula (a)₁Is formed to pass through the clearance C₁The lubricating oil r of (2) exerts a so-called self-control throttling action of the squeezing action. Therefore, the gap C can be formed without using a mechanical member₁A good oil film is formed.When the rotating shaft 12 is eccentric in the radial direction by vibration or the like, the rotation speed is changed in the clearance C₁Narrowed region R₁The pressure loss becomes large and becomes high pressure. Therefore, a restoring force in a direction opposite to the eccentric direction acts on the rotary shaft 12, and the rotary shaft 12 returns to the clearance C₁A region R widened to become a low pressure₂And (3) side. Thus, the gap C can be formed₁The oil film is maintained, and vibration of the rotary shaft 12 can be damped even if the rotary shaft 12 vibrates.

In one embodiment, as shown in fig. 1, the bearing device 10 is provided to rotatably support the rotary shaft 12 of the rotating device 50. The rotary device 50 according to the embodiment illustrated in fig. 1 is a turbocharger, and the bearing device 10 is housed inside a housing 16 forming a part of a bearing housing 64. The turbocharger includes a compressor 52 and a turbine 54 at both ends of the rotary shaft 12. The compressor 52 is provided with a plurality of compressor blades 58 radially around the compressor wheel 56. The turbine 54 is provided with a plurality of turbine blades 62 radially around the turbine wheel 60. An oil passage 68 for the lubricating oil r communicating with the oil supply hole 24 is formed in the bearing housing 64. In fig. 1, a compressor housing that houses the compressor wheel 56 and the compressor blades 58, and a turbine housing that houses the turbine wheel 60 and the turbine blades 62 are not shown.

In one embodiment, as shown in fig. 1 and 2, the rotating device 50 includes a thrust bearing 66, and the thrust bearing 66 supports a thrust load applied to the rotating shaft 12. In fig. 2, the housing 16 disposed opposite the rolling bearing 14 is not necessarily limited to the main body portion of the housing 16, and includes accessories such as a bearing housing and a sleeve attached to the main body of the housing 16. In addition, as necessary, some measures (not shown) for suppressing the rotation stop of the rotary shaft 12 in the circumferential direction are applied to the rolling bearing 14.

In one embodiment, as shown in fig. 3, high-pressure lubricant r is supplied from a lubricant supply source (not shown) such as a lubricant tank (not shown) to the plurality of oil supply holes 24(24a to 24d) through a pipe 26 by a pump 28.

FIG. 5 is an enlarged view of part A of FIG. 2, and FIG. 6 is a view of another embodimentPart A in the formula corresponds to the figure. In one embodiment, as shown in fig. 5 and 6, a gap C is formed between the first and second substrates₁The facing surface 22a (32a) facing the inner surface 16a of the case 16 is formed with recesses 30(30a, 30b) (first recesses). The facing surface 22a (32a) refers to the outer peripheral surface 22a of the outer ring 22 in the embodiment shown in fig. 5, and refers to the outer peripheral surface 32a of the cover member 32 in the embodiments shown in fig. 7 and 8. The recess 30 is formed to be aligned with the axis O of the rotary shaft 12₁The cross-sectional area in the orthogonal direction decreases from the position where the cross-sectional area is largest toward at least one side in the axial direction of the rotary shaft 12.

In one embodiment, the recess 30 is formed in an elliptical shape, a rectangular shape, or the like, for example, when viewed from the housing 16 side. In the embodiment shown in fig. 5, the recess 30(30a) is configured such that the depth thereof becomes smaller toward the axial direction side, but even if the depth is constant in the axial direction, the interval between the side surfaces forming the recess (the width dimension of the recess 30) may be configured such that it becomes narrower toward the axial direction side.

According to this embodiment, the oil supply hole 24 is formed through the clearance C₁The lubricating oil r supplied to the recessed portion 30 is accelerated along the surface of the recessed portion 30 in the axial direction of the rotating shaft 12, and a vertical component force Pd is generated on the surface of the recessed portion 30 by the dynamic pressure of the lubricating oil r. The vertical component force Pd is a force for returning the eccentric rotating shaft 12 to a stationary position. Therefore, the pair of passing gaps C can be simultaneously achieved₁The self-control throttling effect of the oil film and the radial aligning effect of the rotating shaft 12 by the dynamic pressure of the lubricating oil r. This can maintain the oil film in the recess 30, and can exhibit a vibration damping effect even when the rotary shaft 12 vibrates in the radial direction.

The recess 30 is provided on the facing surface 22a (32a) facing the outlet opening of the at least one oil supply hole 36.

The plurality of oil feed holes 24(24a to 24d) may be formed in a direction orthogonal to the outer peripheral surface of the outer ring 22 at least in the vicinity of the outlet opening. This reduces the pressure loss of the lubricating oil r, and increases the vertical component force Pd acting on the surface of the recess 30.

In one embodiment, as shown in fig. 5, the recess 30(30a) is configured such that the depth thereof decreases toward one side in the axial direction. Is supplied from the oil supply hole 24The lubricating oil r reaching the recessed portion 30(30a) flows along the surface of the recessed portion 30(30a), is accelerated in the axial direction, and generates a vertical component force Pd with respect to the surface of the recessed portion 30(30a) by the dynamic pressure of the lubricating oil r. Therefore, the clearance C can be further increased₁A self-control throttling effect by the lubricating oil r, and a radial aligning effect of the rotating shaft 12 by the dynamic pressure of the lubricating oil r.

In one embodiment, as shown in fig. 6, the recess 30(30b) is configured such that the cross-sectional area decreases from the position where the cross-sectional area is largest toward one side and the other side in the axial direction, respectively. Further, the cross-sectional area is set to be the largest position P₁Distance L to one end in axial direction₁A distance L from the position with the largest cross-sectional area to the end part on the other side in the axial direction₂Are equal.

When the lubricant r is supplied to the recess 30(30b), the lubricant r is branched on the surface of the recess 30(30b) toward one or the other of the axial directions. Therefore, a force for moving the rotary shaft 12 to one side or the other side can be generated depending on the position of the lubricant r to be supplied. For example, when the lubricant oil is supplied to the position where the cross-sectional area is the largest, the distribution of the vertical component force Pd generated on the surface of the recess 30(30b) along the axial direction is symmetrical about the position where the cross-sectional area is the largest. Therefore, when the rotary shaft 12 moves from the stationary position to the axial direction due to vibration or the like, the distribution of the vertical component force Pd generated on the surface of the recess 30(30b) along the axial direction becomes asymmetric. Therefore, the dynamic pressure of the lubricating oil r acting on the surface of the recess 30(30b) in the direction opposite to the moving direction of the rotary shaft 12 increases, and a force for returning the rotary shaft 12 to the original statically fixed position is applied. Therefore, the self-control throttling effect of the oil film and the radial aligning effect by the dynamic pressure of the lubricating oil r can be exerted, and the aligning effect in the thrust direction can be exerted.

In one embodiment, as shown in fig. 5 and 6, the recess 30(30a, 30b) is configured such that the position having the largest cross-sectional area faces the outlet opening of the oil supply hole 24. In addition to the operational effects of the above-described embodiment, when the rotary shaft 12 is at the stationary position, the lubricant r discharged from the outlet opening of the oil supply hole 24 is supplied to the position where the cross-sectional area of the recess 30 is maximized, and therefore, the kinetic energy of the lubricant r can be efficiently converted into the dynamic pressure acting on the surface of the recess 30.

In one embodiment, the position P where the cross-sectional area of the recess 30(30a, 30b) is the largest₁Is configured to be in contact with the center point P of the outlet opening of the oil supply hole 24₂In opposite directions. I.e. point P₁And a central point P₂Is configured to be positioned at a perpendicular line O₂The above. Accordingly, when the rotary shaft 12 is at the stationary position, the lubricant oil r discharged from the outlet opening of the oil supply hole 24 is accurately supplied to the position where the cross-sectional area of the recess 30 is maximized, and therefore, the kinetic energy of the lubricant oil r can be efficiently converted into the dynamic pressure acting on the surface of the recess 30.

Fig. 6 shows that vibration of the rotary shaft 12 is generated and the rolling bearing 14 moves from the stationary position in the arrow direction (right side of the drawing) together with the rotary shaft 12. When the rotary shaft 12 moves from the stationary position to one of the axial directions, the distribution of the vertical component force Pd formed on the surface of the recess 30(30b) along the axial direction becomes asymmetric as shown in the drawing. That is, the vertical component force Pd generated on the surface of the recess 30(30b) in the direction opposite to the moving direction of the rotary shaft 12 increases. By the difference in the asymmetric vertical component force Pd, a force is applied to return the rotary shaft 12 to the original statically fixed position in the thrust direction. Thus except by the clearance C₁The self-control throttling action of the oil film and the radial aligning effect by the dynamic pressure of the concave portion 30(30b) can exert the aligning effect in the thrust direction.

In one embodiment, the cross-section of the recess 30(30b) has a circular arc shape. In addition, in one embodiment, there is a point P of relative passing in a static position₁Perpendicular line O perpendicular to the outer peripheral surface of the outer ring 22₂Left-right symmetrical shape. Thus, when the rotation axis 12 is at the stationary position, the distribution of the vertical component force Pd with respect to the vertical line O₂Left-right symmetry, and vertical component force Pd balance in the axial direction. Thus, when the rotary shaft 12 moves from the stationary position to the axial direction due to vibration or the like, the asymmetric distribution of the vertical component force Pd can be developed with good sensitivity, and therefore, the force for returning the rotary shaft 12 can be developed with good sensitivity.

In one embodiment, the bearing device 10(10B) shown in fig. 7 includes a plurality of rolling bearings 14(14a, 14B) provided at intervals in the axial direction of the rotary shaft 12, and a cover member 32 is provided so as to cover the outer peripheries of the plurality of rolling bearings 14. The concave portion 30 is provided on the outer peripheral surface 32a (facing surface) of the cover member 32. The recess 30 may be the recess 30(30a) shown in fig. 5, or may be the recess 30(30b) shown in fig. 6. Since the recesses 30 are formed in the outer peripheral surface 32a of the cover member 32, the dynamic pressure of the lubricating oil r is transmitted to the plurality of rolling bearings 14(14a, 14b) via the cover member 32. Therefore, since uniform force acts on each rolling bearing 14 from the cover member 32 and each rolling bearing 14 is operated in unison by the cover member 32, the centering effect with respect to the rotary shaft 12 can be improved.

In one embodiment, when the recesses 30(30a) are formed in the outer peripheral surface 32a of the cover member 32, the two recesses 30(30a) are formed so that the directions of gradually decreasing cross-sectional areas are opposite to each other. Thus, the vertical component forces Pd other than the radial direction are generated in opposite directions in the two recesses 30(30a), and cancel each other out. Therefore, no excessive force is applied in the thrust direction.

In one embodiment, the cover member 32 has a substantially cylindrical shape, but the partition wall forming the outer peripheral surface 32a may be present at least at a position facing the oil supply hole 24. The cover member 32 has a regulating portion 34 on the inner side for regulating the axial movement of the rolling bearing 14. The restricting portion 34 has an annular recess into which the outer ring 22 of the rolling bearing 14 is fitted, and the outer ring 22 is fitted into the recess to restrict axial movement.

In one embodiment, in the bearing device 10(10C) shown in fig. 8, an oil supply hole 36 (second oil supply hole) and an oil supply hole 38 (third oil supply hole) are formed in the housing 16. The oil supply hole 36 is formed in the gap C between the axial end surface 32b of the cover member 32 and the inner surface 16a of the housing 16₂(second gap) is supplied with the lubricating oil r. The oil supply hole 38 is formed to extend to a clearance C between the axial end surface 32C of the cover member 32 and the inner surface 16b of the housing 16₃(third gap) is supplied with the lubricating oil r. D represents the diameter of the outlet opening of the oil supply hole 36₂Will be spaced apart by a distance C₂Is set to be delta₂D represents the diameter of the outlet opening of the oil supply hole 38₃Will be spaced apart by a distance C₃Is set to be delta₃The oil supply hole 36 satisfies the following expression (b), and the oil supply hole 38 satisfies the following expression (c).

π·d₂·δ₂<π·d₂ ²/4 (b)

π·d₃·δ₃<π·d₃ ²/4 (c)

According to this embodiment, the lubricating oil r supplied from the oil supply hole 36 and the oil supply hole 38 passes through the clearance C₂And a gap C₃Since the self-control throttle by the squeezing action of the oil film is formed, the clearance C can be formed without using a mechanical member₂And a gap C₃A good oil film is formed. Further, even when the rotary shaft 12 moves from the stationary position to one or the other in the thrust direction due to vibration, the vibration in the thrust direction can be attenuated, and the centering effect of returning to the original stationary position can be exhibited. Therefore, the bearing device 10(10C) can achieve both the radial aligning effect by the self-controlled throttling of the lubricating oil r supplied from the oil supply hole 24 and the thrust direction aligning effect by the self-controlled throttling of the lubricating oil r supplied from the oil supply holes 36 and 38.

In one embodiment, the oil supply holes 36 and 38 are formed in plurality at equal intervals in the circumferential direction of the rotary shaft 12. The oil supply holes 36 and 38 are formed in a direction orthogonal to the inner peripheral surface of the housing 16 at least in the vicinity of the outlet opening. This reduces the pressure loss of the lubricating oil, and increases the vertical component force Pd generated on the surfaces of the recesses 40 and 42.

In one embodiment, as shown in FIG. 9, a gap C is provided between the first and second substrates₂A recess 40 is formed in an axial end face 32b of the cover member 32 facing the inner side face 16a of the housing 16. In addition, a gap C is arranged between the two₃A recess 42 is formed in an axial end face 32c of the cover member 32 facing the inner side face 16b of the housing 16. The recesses 40 and 42 are formed to be aligned with the axis O of the rotary shaft 12₁The cross-sectional area in the parallel direction decreases from the position where the cross-sectional area is largest toward at least one side in the radial direction of the rotary shaft 12.

According to this embodiment, since the lubricating oil r supplied from the oil supply hole 36 to the recess 40 is accelerated in the radial direction, a vertical component force Pd is generated on the surface of the recess 40 by the dynamic pressure of the lubricating oil r. The vertical component force Pd is a force that returns the rotating shaft 12 moving in the thrust direction to the stationary position. The same vertical component force also acts on the lubricating oil r supplied from the oil supply hole 38 to the recess 42. Therefore, in the present embodiment, the self-control throttling effect of the oil film and the centering effect of the radial direction of the rotating shaft 12 by the dynamic pressure of the lubricating oil r can be achieved at the same time. This can exhibit a vibration damping effect even when vibration occurs in the radial direction in the rotary shaft 12. Therefore, the bearing device 10(10C) can achieve both the self-control throttling effect on the oil film supplied from the oil supply hole 24 and the radial alignment effect by the concave portion 30, and the self-control throttling effect on the oil film supplied from the oil supply holes 36 and 38 and the thrust direction alignment effect by the concave portions 40 and 42.

In one embodiment, recesses 40 and 42 have the same shape as recess 30(30a) or recess 30(30 b). This can exert a centering effect in the radial direction due to the vertical component force Pd generated on the surface of the recess 30(30a, 30 b).

In one embodiment, in the bearing device 10(10C) shown in fig. 8, only the oil supply holes 36 and 38 may be provided without providing the oil supply hole 24 and the recess 30. Thus, the lubricating oil r supplied from the oil supply holes 36 and 38 passes through the clearance C₂And C₃And when the oil film is used, self-control throttling based on the squeezing action of the oil film is formed. Thus, the gap C can be formed without using a mechanical member₂And C₃A good oil film is formed, and when the rotary shaft 12 moves from the stationary position to one or the other in the thrust direction due to vibration, vibration in the thrust direction can be attenuated, and the centering effect of returning to the original stationary position can be exhibited.

In one embodiment, as shown in fig. 9, only the oil supply holes 36 and 38 and the recesses 40 and 42 may be provided without providing the oil supply hole 24 and the recess 30. Thereby, the gap C can be used₂And C₃A self-control throttling effect on an oil film and a radial aligning effect of the rotating shaft 12 by dynamic pressure of the lubricating oil r. Therefore, even if a radial direction is generated at the rotating shaft 12The vibration of (2) can also exhibit a vibration damping effect. Therefore, the thrust bearing provided in the rotary shaft can be eliminated depending on the situation.

Since the rotating device 50 shown in fig. 1 includes the bearing device 10 according to each of the embodiments described above, a self-controlled throttle by a squeezing action of a lubricating oil film can be formed in a gap between the rolling bearing 14 and the housing 16 that houses the rolling bearing 14. Therefore, the radial eccentricity of the rotary shaft 12 due to vibration can be suppressed, and the vibration damping effect of the rotary shaft 12 can be exhibited.

The rotary device shown in fig. 1 is exemplified by a turbocharger, but the above embodiments can be applied to other rotary devices having a rotary shaft.

Industrial applicability

According to some embodiments, in a rotating device including a rotating shaft, when the rotating shaft is supported by a rolling bearing, vibration can be effectively suppressed without using a mechanical member.

Description of the reference numerals

10(10A, 10B, 10C) bearing device

12 rotating shaft

14(14a, 14b) rolling bearing

16 casing

16a, 16b inner side

18 inner ring

20 rolling element

22 outer ring

22a peripheral surface (opposite surface)

24(24a, 24b, 24c, 24d) oil supply hole (first oil supply hole)

26 pipeline

28 Pump

30(30a, 30b) concave portion (first concave portion)

32 cover component

32a peripheral surface (opposite surface)

32b, 32c axial end faces

34 restriction part

36 oil supply hole (second oil supply hole)

38 oil supply hole (third oil supply hole)

40 recess (second recess)

42 recess (third recess)

50 rotating device

52 compressor

54 turbine

56 compressor impeller

58 compressor blade

60 turbine wheel

62 turbine blade

64 bearing shell

66 thrust bearing

68 oil circuit

C₁Gap (first gap)

C₂Clearance (second clearance)

C₃Clearance (second clearance)

O₁Axial line

O₂Center line

P₂Center point

Vertical component force of Pd

Lubricating oil