JP2005172099A - Turbocharger bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbocharger bearing device keeping its manufacturing cost down by reducing the number of parts while simplifying construction. <P>SOLUTION: The turbocharger bearing device 1 for rotatably supporting a rotating shaft 31 of a turbocharger T in a housing H comprises a pair of outer rings 3, 4 with outer ring raceways 3a, 4a provided at both ends of an almost cylindrical inner ring 2 with an inner ring raceway 2a to form two bearings A, A. A spring is mounted only on the outside of one outer ring 3 for imparting preload to the bearings. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a bearing device that rotatably supports a rotating shaft of a turbocharger of an automobile.

Recently, there has been a demand for fuel-saving and low-emission vehicles, and the number of vehicles equipped with turbochargers is increasing. Rolling bearings (hereinafter referred to as bearings) are used to rotatably support the turbocharger within the housing. The usage environment of such a bearing is extremely severe, such as ultra-high rotation, ultra-high acceleration / deceleration, and ultra-high temperature, and high rotational accuracy is required. For that purpose, it is indispensable to give an appropriate preload to the bearing. Therefore, it is suitable to apply a constant pressure preload to the bearing. In order to apply the constant pressure preload, there has already been proposed a structure in which a spring for applying a preload between two bearings each having an outer ring and an inner ring and two kinds of sleeves required for this are incorporated (for example, a patent) Reference 1).
Japanese Patent Laid-Open No. 10-19045 (FIG. 3)

However, the above-described turbocharger bearing device has a complicated structure and a large number of parts, which increases the number of assembly steps and the cost of parts, and thus increases the manufacturing cost.
In view of such circumstances, an object of the present invention is to provide a turbocharger bearing device in which the structure is simplified, the number of parts is reduced, and the manufacturing cost is suppressed.

In order to achieve the above object, the present invention takes the following technical means.
That is, the present invention is a turbocharger bearing device that rotatably supports a rotating shaft of a turbocharger in a housing, and is fitted to an outer peripheral surface of the rotating shaft, and an inner ring raceway is formed on an outer peripheral surface near both ends. A substantially cylindrical inner ring formed, and a pair of outer rings attached to the housing and having an outer ring raceway facing the inner ring raceway formed on an inner circumferential surface and arranged with their axially inner ends facing each other; A plurality of rolling elements that are freely rollable between the inner ring raceways of the inner rings and the outer ring raceways of the outer rings, and a stopper portion of the housing that restricts one outer ring from moving outward in the axial direction. And a spring that is mounted between an axially outer end portion of the other outer ring and a spring receiving portion of the housing facing the outer ring, and biases the outer ring to apply a preload to the bearing. Features that It is intended to.

According to the turbocharger bearing device, two outer rings and the like are attached to one inner ring, and a spring that applies preload only to the outer side of one outer ring is attached to the other outer ring via the rolling element and the inner ring. Can also apply preload. In this way, the spring is eliminated from the space between the outer rings and the spacer can be omitted, so that the structure is simplified and the number of parts is small.
Further, in the turbocharger bearing device, it is preferable that a stepped portion notched in an annular shape is formed on the outer peripheral side of the axially outer end portion of the outer ring, and one end of the spring is fixed to the stepped portion. . As a result, it is possible to prevent the spring attached to the outer side of the outer ring from falling off the outer ring.
Furthermore, in the turbocharger bearing device, it is preferable that a concave portion forming a gap is formed on the inner peripheral surface of the inner ring with the rotary shaft within a required range in the axial direction. In this case, the contact area between the rotating shaft and the inner ring can be reduced, so that the pressure input of the inner ring to the rotating shaft can be reduced, and the impression of the rotating shaft during press fitting can be prevented. At this time, the inner diameter of the inner ring and the outer diameter of the rotating shaft are adjusted so that the pressure input becomes smaller than the indentation generation load.

  According to the present invention, the inner ring of the two bearings is made as one member, and the spring is extended outside to apply the preload from the outside of one of the bearings, so the number of parts is reduced while simplifying the structure. , Manufacturing costs can be suppressed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing an embodiment of a turbocharger bearing device 1 according to the present invention. FIG. 2 is a plan view thereof. FIG. 3 shows a schematic configuration of a turbocharger T in which the turbocharger bearing device 1 is incorporated in the housing H. The turbocharger T rotates the turbine 32 fixed to one end (the right side in FIG. 3) of the rotating shaft 31 by the exhaust flowing through the exhaust passage 30. The rotation of the rotating shaft 31 is transmitted to the impeller 33 fixed to the other end (left side in FIG. 3) of the rotating shaft 31, and the air sucked in the intake passage 34 is compressed by the impeller 33. Thereby, the compressed air together with fuel such as gasoline and light oil is sent into the cylinder chamber of the engine. The rotating shaft 31 of such a turbocharger T rotates at a high speed of several tens of thousands to several tens of thousands of times / minute, and the rotation speed frequently changes according to the operating state of the engine. Therefore, the rotating shaft 31 is supported with respect to the housing H with a small rotational resistance by the turbocharger bearing device 1 incorporated in the housing H in order to reduce the rotation loss.

  The turbocharger bearing device 1 supports a rotating shaft 31 having a turbine 32 attached to one end and an impeller 33 attached to the other end so as to be rotatable with respect to a housing H. As shown in FIGS. 1 and 2, the turbocharger bearing device 1 is transferred to an inner ring 2, a pair of outer rings 3, 4 (first outer ring 3, second outer ring 4), and an annular space between them. Angular bearings (hereinafter referred to as “bearings”) A and A each composed of a plurality of rolling elements 5 that are movably disposed and a cage 11 that holds the rolling elements 5, and a preload is applied to the bearings A and A. And a spring 6 to be applied. As shown in FIG. 1, the turbocharger bearing device 1 has a plate member 35 as a stopper member attached to a housing H with a right end (hereinafter, the right side in FIG. 1, the opposite side is called the left side) of the second outer ring 4. Further, the cylindrical spacer 36 is brought into contact with the left end portion of the inner ring 2, the axially outer (left side) end portion 3 e of the first outer ring 3, and the spring receiver of the housing H opposed thereto. A space 37 formed between the portion H1 is provided with a spring 6 for applying a preload to the bearing.

The constituent members of the turbocharger bearing device 1 will be described in more detail. The turbocharger bearing device 1 is configured as a bearing unit including two bearings A and A by attaching two outer rings 3 and 4 to one cylindrical inner ring 2.
The inner ring 2 is formed in a substantially cylindrical shape whose longitudinal direction is the axial direction of the rotating shaft 31 (hereinafter referred to as the axial direction), and an angular inner ring raceway 2a having a predetermined radius of curvature is formed on the outer peripheral surfaces of both ends thereof. Is formed. The inner ring 2 has inner ring extending portions 2b extending outward in the axial direction from the inner ring raceways 2a and cylindrical portions 2c extending inward from the inner ring raceways 2a. The axis of each inner ring raceway 2a is directed outward. The cylindrical portion 2c is slightly thicker than each inner ring extending portion 2b. On the inner peripheral surface of the inner ring 2, a recess 7 is formed that forms a gap with the rotary shaft in a range that covers approximately three-fifths of the axial length.

The inner ring 2 is manufactured, for example, by deep drawing a steel sheet such as a cold-rolled steel sheet to form the inner ring raceway 2a so as to have a predetermined curvature radius, and then performing heat treatment including carburizing quenching and induction quenching. can do.
The pair of outer rings 3 and 4 are provided with axially inner end portions 3f and 4f facing each other. Among these, the left first outer ring 3 is formed with a width extending from a position slightly shifted outward in the axial direction from the left end of the inner ring 2 to the axial central portion of the inner ring 2, and the second outer ring 4 is The inner ring 2 is formed with a width extending from the axial center portion of the inner ring 2 to the right end of the inner ring 2. The first outer ring 3 and the second outer ring 4 are angular-type outer ring raceways 3a and 4a that face the inner ring raceway 2a of the inner ring 2 and have a predetermined radius of curvature, and extend outwardly in the axial direction from the outer ring raceways 3a and 4a. The outer ring extending portions 3b and 4b are provided, and the outer ring cylindrical portions 3c and 4c are extended from the outer ring raceways 3a and 4a to the inside. The outer ring cylindrical portions 3c and 4c are slightly thinner than the outer ring extending portions 3b and 4b. Further, notched engaging portions 8 and 8 are formed at portions where the first outer ring 3 and the second outer ring 4 face each other and face each other. The engaging portions 8 and 8 are formed with dimensions that can be engaged with a pin member 38 to be described later, and a portion where the engaging portion 8 of the first outer ring 3 and the engaging portion 8 of the second outer ring 4 are combined, A pin member 38 provided in the housing H is engaged. Note that the shape of the engaging portion 8 is not limited to an angular shape, and may be a semi-cylindrical shape. In short, any shape that can engage with the pin member 38 may be used.

A tapered surface 9 is formed in the axial center portion of the outer rings 3 and 4, and an oil hole 10 having a required diameter passes through the inner peripheral surface of the outer rings 3 and 4 diagonally outward from a midway portion of the tapered surface 9. Is formed. And the penetration exit to the internal peripheral surface of the oil hole 10 is the vicinity of the inner ring track 2a.
On the left side of the first outer ring 3, a step part 3d that is cut out in an annular shape is formed. By attaching the spring 6 to this part so as to slightly expand the diameter, the right end of the spring 6 becomes the first end. It is fixed to the outer ring 3 and cannot be removed naturally. The step portion 3d is formed so as to slightly enter the radially inner side from the outer peripheral surface in the vicinity of the end portion of the first outer ring 3 and to be bent at a right angle from there. The outer rings 3 and 4 are subjected to heat treatment including carburizing quenching and induction quenching after forming outer ring raceways 3a and 4a so as to have a predetermined curvature radius by deep drawing a steel plate such as a cold rolled steel plate, for example. Can be manufactured.

The plurality of rolling elements 5 have a predetermined spherical diameter by a retainer 11 such that they can roll into an annular space formed between the outer ring raceways 3 a, 4 a of the outer rings 3, 4 and the inner ring raceway 2 a of the inner ring 2. Is arranged. These rolling elements 5 are manufactured from various steel materials such as stainless steel. The cage 11 partially surrounds the plurality of rolling elements 5. In addition, although this holder | retainer 11 changes with usages, various resin, such as polyamide other than steel materials, is manufactured. The form of the cage 11 is arbitrary such as a corrugated shape or a machined shape.
The spring 6 mounted in the above-described space 37 is a coil spring having a predetermined spring constant, and biases the first outer ring 3 to the right side, thereby applying a preload to the bearing. In addition, this urging force is transmitted to the second outer ring 4 via the inner ring 2 and the right rolling element 5 and pushes it to the right side, but the movement is restricted by the plate member 35 fixed to the housing H, As a result of receiving the reaction force, the same preload as that of the left bearing is applied to the right bearing.

  As a procedure for assembling the turbocharger bearing device 1, first, the inner ring 2 is prepared, and the first outer ring 3 and the second outer ring 4 are assembled to the inner ring 2. Then, a spring 6 is mounted on the left side of the first outer ring 3. In the turbocharger bearing device 1 disposed at a predetermined location in the housing H, the spacer 36 is brought into contact with the left end portion of the inner ring 2, and the plate member 35 is brought into contact with the right end portion of the second outer ring 4. . Thereafter, a pin member 38 having a required dimension provided at a substantially central portion of the housing H is engaged with a space formed by the engaging portions 8 of the outer rings 3 and 4. When the pin member 38 engages with the engaging portion 8, the turbocharger bearing device 1 is fixed and positioned on the housing H, and at the same time, rotation and movement in the left-right direction are restricted.

  Such a turbocharger bearing device 1 has a simplified structure in which two outer rings 3, 4, etc. are attached to one inner ring 2 and a spring 6 that applies preload only to the outer side of one outer ring 3 is mounted. The bearing unit includes two bearings A and A having a small number of parts. Therefore, the turbocharger bearing device 1 can be manufactured at low cost. Furthermore, since the integrated bearings A and A are inserted into the housing H and only one spring 6 is mounted in the space 37, the manufacturing cost of the turbocharger T can be easily and quickly assembled. Can also be suppressed. Further, the relative rotation of the outer rings 3 and 4 with respect to the housing H is restricted by the engagement of the engaging portion 8 and the pin member 38. Further, since the end portion of the spring 6 is fitted into the stepped portion 3d that is annularly cut out on the outer side of the first outer ring 3, it is possible to prevent the spring 6 from dropping off from the first outer ring 3.

Further, since the concave portion 7 that forms a gap with the rotary shaft 31 is formed on the inner peripheral surface of the inner ring 2, the pressure input to the rotary shaft 31 can be reduced. Therefore, indentation of the rotating shaft 31 during press-fitting can be prevented, and the rotating shaft 31 is not damaged. At this time, the inner diameter of the inner ring 2 and the outer diameter of the rotary shaft 31 are adjusted so that the pressure input is smaller than the indentation generation load.
Further, since the oil hole 10 is disposed in the vicinity of the inner ring raceway 2a, a good lubricating effect can be obtained. Further, since the outer rings 3 and 4 and the housing H are positioned by the engaging portion 8, the positions of the oil supply passage 39 of the housing H and the oil holes 10 of the outer rings 3 and 4 do not shift. The housing H is provided with an oil supply passage 39 so that the bearings A and A can be cooled and lubricated. That is, during operation of the engine equipped with the turbocharger T, the lubricating oil is removed of foreign matters by a filter provided at the upstream end of the oil supply passage 39, so that the inner peripheral surface of the housing H and the outer peripheral surfaces of the outer rings 3, 4 It is fed into an annular gap space provided between them. The gap space is provided by fitting the housing H and the outer rings 3 and 4 with a gap. Then, by filling this gap space with lubricating oil, an oil film (oil film) is formed over the entire circumference between the outer peripheral surfaces of the outer rings 3 and 4 and the inner peripheral surface of the housing H. An oil film damper is configured that cools the angular bearings A and A and attenuates vibrations based on the rotation of the rotating shaft 31. A part of the lubricating oil fed into the gap space passes through the oil hole 10 and is ejected obliquely from the outside in the radial direction toward the outer peripheral surface of the inner ring 2 to cool and lubricate the angular bearings A, A (oil jet Lubricate).

In addition, this invention is not limited to the form of each above-mentioned Example.
For example, the shapes of the outer rings 3 and 4 and the dimensions of the engaging portion 8 and the stepped portion 3d may be changed, and the recess 7 formed on the inner peripheral surface of the inner ring 2 may be narrowed or separated.

It is sectional drawing which shows 1st embodiment of the turbocharger bearing apparatus concerning this invention. It is the same top view. It is sectional drawing which shows schematic structure of the turbocharger in which the turbocharger bearing device was incorporated.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbocharger bearing apparatus 2 Inner ring 3 1st outer ring 3d Step part 4 Second outer ring 6 Spring 7 Recess 8 Engagement part 9 Oil hole 31 Rotating shaft 32 Turbine 33 Impeller 35 Plate material 36 Spacer 37 Space 38 Pin member

Claims (3)

A turbocharger bearing device for rotatably supporting a rotating shaft of a turbocharger in a housing,
A substantially cylindrical inner ring that is fitted to the outer peripheral surface of the rotating shaft and has an inner ring raceway formed on the outer peripheral surface in the vicinity of both ends.
A pair of outer rings attached to the housing, wherein an outer ring raceway facing the inner ring raceway is formed on an inner peripheral surface, and arranged with the axially inner ends facing each other;
A plurality of rolling elements arranged in a freely rollable manner between each inner ring raceway of the inner ring and an outer ring raceway of each outer ring;
A stopper portion of the housing for restricting one outer ring from moving outward in the axial direction;
A spring that is mounted between an axially outer end of the other outer ring and a spring receiving part of the housing facing the outer ring and biases the outer ring to apply a preload to the bearing; A turbocharger bearing device.   2. The turbocharger bearing device according to claim 1, wherein a stepped portion that is cut out in an annular shape is formed on an outer peripheral side of an axially outer end portion of the outer ring, and one end of the spring is fixed to the stepped portion.   The turbocharger bearing device according to claim 1 or 2, wherein a concave portion that forms a gap with a rotation shaft in a required range in the axial direction is formed on an inner peripheral surface of the inner ring.

Images