JP2007046642A - Supercharger and fully floating bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbocharger capable of suppressing self-excited vibration. <P>SOLUTION: The turbocharger 1 is equipped with a turbine shaft 21, a compressor 11 and a turbine 31 provided at both ends of the turbine shaft 21, a center housing 20 with a holding part 46 for holding the turbine shaft 21, an inner circumference face 420 and an outer circumference face 430, wherein the inner circumference face 420 faces against the turbine shaft 21 with oil 100 intervened and the outer circumference face 430 faces against the holding part 46 with the oil 100 intervened. In addition, the turbocharger 1 is equipped with the cylindrical fully floating bearing 40. An inner circumference spiral groove 42 and an outer circumference spiral groove 43 are provided in at least one of the inner circumference face 420 and the outer circumference face 430. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a supercharger and a full float bearing, and more particularly to a supercharger having a compressor and a turbine and a full float bearing used therein.

Conventionally, the structure of a supercharger is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-88318 (Patent Document 1), Japanese Patent Application Laid-Open No. 1-193409 (Patent Document 2) and Japanese Patent Application Laid-Open No. 2002-213248 (Patent Document 3) It is disclosed in Japanese Society for Invention and Innovation Technique 88-10595 (Non-Patent Document 1).
JP-A-63-88318 JP-A-1-193409 JP 2002-213248 A Invention Association Open Technique 88-10595

  In Patent Document 1, a single circumferential groove is shown on the outer periphery of a full float bearing of a turbocharger.

  Patent Document 2 discloses a structure in which the clearance between the sliding surfaces of the bearing is gradually increased and decreased at a plurality of locations to suppress self-excited vibration of the turbocharger.

  Patent Document 3 discloses a technique for reducing the ratio of the width of the inner and outer peripheral sliding surfaces of the bearing to a predetermined value or less in order to suppress self-excited vibration of the turbocharger.

  Non-Patent Document 1 discloses that a single circumferential groove is provided on the inner periphery of a full float bearing of a turbocharger.

  However, in the above-described conventional technology, the effect of suppressing the self-excited vibration of the turbocharger (supercharger) has not been sufficient.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to suppress the self-excited vibration of the supercharger.

  A full float bearing according to the present invention is a cylindrical full float bearing having an inner peripheral surface and an outer peripheral surface, the inner peripheral surface is opposed to the turbine shaft with a fluid interposed therebetween, and the outer peripheral surface is interposed with a fluid interposed therebetween. Opposite to the holding portion, a spiral groove is provided on at least one of the inner peripheral surface and the outer peripheral surface.

  In the full float bearing configured as described above, the spiral groove is provided on at least one of the inner peripheral surface and the outer peripheral surface. Therefore, when the full float bearing rotates, the spiral groove provided on at least one of the inner peripheral surface and the outer peripheral surface The distribution of pressure that the inner peripheral surface and the outer peripheral surface receive from the fluid changes along the axial direction. For this reason, the full float bearing is unlikely to be in a stable state, and self-excited vibration can be suppressed.

Preferably, spiral grooves are provided on both the inner peripheral surface and the outer peripheral surface.
A turbocharger according to the present invention includes a turbine shaft, compressors and turbines provided at both ends of the turbine shaft, a housing having a holding portion for holding the turbine shaft, an inner peripheral surface and an outer peripheral surface, The peripheral surface is opposed to the turbine shaft with a fluid interposed therebetween, and the outer peripheral surface is opposed to the holding portion with a fluid interposed therebetween and includes a cylindrical full float bearing. A spiral groove is provided on one of the inner peripheral surface and the outer peripheral surface.

  In the turbocharger configured as described above, since the spiral groove is provided on at least one of the inner peripheral surface and the outer peripheral surface, the surface pressure distribution received from the fluid by at least one of the inner peripheral surface and the outer peripheral surface is determined by the full float bearing. It fluctuates by rotating. As a result, the full float bearing can be prevented from entering a stable state, and the occurrence of self-excited vibration can be suppressed.

  Preferably, spiral grooves are provided on both the inner peripheral surface and the outer peripheral surface.

  According to the present invention, a supercharger capable of suppressing self-excited vibration and a full float bearing used therefor can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a turbocharger according to Embodiment 1 of the present invention. Referring to FIG. 1, turbocharger 1 as a supercharger according to the first embodiment of the present invention rotates a turbine using the energy of exhaust gas, and rotates a compressor coaxial with the turbine. This is a device that compresses intake air (or air-fuel mixture) and sends high-density air-fuel mixture or air into the combustion chamber to increase the output. The turbocharger 1 includes a turbine shaft 21, a compressor 11 and a turbine 31 provided at both ends of the turbine shaft 21, a center housing 20 for holding the turbine shaft 21, a compressor housing 10 for housing the compressor 11, and a turbine 31. And a turbine housing 30 for housing.

  The turbine 31 and the compressor 11 are attached to a common turbine shaft 21. The turbine housing 30 is provided with a turbine housing vortex chamber 32. Exhaust gas flows from the exhaust manifold into the turbine housing vortex chamber 32, and the turbine 31 is rotated by the pressure of the exhaust gas. The exhaust gas that has rotated the turbine 31 is discharged from the vicinity of the center of the turbine housing 30 in the axial direction. The turbine housing 30 is in direct contact with the center housing 20.

  The compressor housing 10 has a compressor housing vortex chamber 12. Air or air-fuel mixture supplied in the axial direction from near the center of the compressor housing 10 is compressed by the compressor 11 and sent to the compressor housing vortex chamber 12. As a result, the sucked air or air-fuel mixture is compressed and its density increases.

  The turbocharger 1 according to the present invention is used as a supercharger for an internal combustion engine such as a gasoline engine or a diesel engine. Furthermore, the turbocharger 1 of the present invention can be used as a supercharger for a rotary engine as well as a reciprocating engine. The turbine shaft 21 that connects the compressor 11 and the turbine 31 is held by a holding portion 46 of the center housing 20. The center housing 20 has a hollow shape, and oil 100 is supplied into the center housing 20 as indicated by an arrow 22. The oil 100 functions to cool the rotating portion of the turbine shaft 21 and lubricate the turbine shaft 21. The full float bearing 40 is held by the holding portion 46. The supplied oil 100 is discharged in the direction indicated by the arrow 23.

  The full float bearing 40 has a cylindrical shape and does not directly contact the holding portion 46 but faces the holding portion 46 with the oil 100 interposed therebetween. The turbine shaft 21 is positioned on the inner peripheral surface side of the cylindrical shape. Oil 100 is interposed between the turbine shaft 21 and the full float bearing 40, and the turbine shaft 21 is not in direct contact with the full float bearing 40. The full float bearing 40 is restricted from moving in the axial direction by a ring member 49. An inner peripheral spiral groove 42 and an outer peripheral spiral groove 43 are provided on the inner peripheral surface 420 and the outer peripheral surface 430 of the full float bearing 40.

  That is, the turbocharger 1 according to the first embodiment is a center as a housing having the turbine shaft 21, the compressor 11 and the turbine 31 provided at both ends of the turbine shaft 21, and a holding portion 46 that holds the turbine shaft 21. The housing 20 includes an inner peripheral surface 420 and an outer peripheral surface 430. The inner peripheral surface 420 faces the turbine shaft 21 with the oil 100 interposed therebetween, and the outer peripheral surface 430 faces the holding portion 46 with the oil 100 interposed therebetween. And a full float bearing 40 having a cylindrical shape. A spiral groove is provided on at least one of the inner peripheral surface 420 and the outer peripheral surface 430. In this embodiment, the inner peripheral spiral groove 42 is provided on the inner peripheral surface 420, and the outer peripheral spiral groove 43 is provided on the outer peripheral surface 430. In addition, it is not necessary to provide a groove in both, and the inner peripheral spiral groove 42 may be provided only in the inner peripheral surface 420. Furthermore, the outer peripheral spiral groove 43 may be provided only on the outer peripheral surface 430.

  FIG. 2 is a perspective view of the full float bearing in FIG. Referring to FIG. 2, the full float bearing 40 has a cylindrical shape, and a plurality of oil feeding holes 41 are provided near the center thereof. The number of the plurality of oil feeding holes 41 is not particularly limited. Further, a plurality of oil feeding holes 41 may be provided at the same pitch, or a plurality of oil feeding holes 41 may be provided at different pitches. In FIG. 2, only two oil feeding holes 41 are illustrated, but four oil feeding holes 41 are provided along the outer periphery of the full float bearing 40.

  The inner peripheral surface 420 is provided with an inner peripheral spiral groove 42. Although the inner circumferential spiral groove 42 is configured to draw a spiral at a constant pitch in FIG. 2, the inner circumferential spiral groove 42 is not limited to this, and the inner circumferential spiral groove 42 may be provided at a non-uniform pitch. In this case, the pitch of the inner circumferential spiral groove 42 is reduced in a part, and the pitch of the inner circumferential spiral groove 42 is increased in another part. In FIG. 2, the inner circumferential spiral groove 42 that rotates approximately once between both ends of the full float bearing 40 is shown. However, the number of rotations is not limited, and one or more turns between both ends of the full float bearing 40. That is, the inner peripheral spiral groove 42 having a smaller pitch than that in FIG. 2 may be provided.

  An outer peripheral spiral groove 43 is provided on the outer peripheral surface 430. In FIG. 2, the pitches of the inner circumferential spiral groove 42 and the outer circumferential spiral groove 43 are substantially equal. However, the pitch is not limited to this, and the pitch between the inner circumferential spiral groove 42 and the outer circumferential spiral groove 43 may be different.

  Next, the operation of the full float bearing according to the present invention will be described. 3 to 5 are views for explaining the operation of the full float bearing according to the first embodiment of the present invention, and are sectional views showing an enlarged portion surrounded by III in FIG. .

  Referring to FIG. 3, the outer peripheral surface 430 of the full float bearing 40 faces the holding portion 46. Oil 100 is interposed between outer peripheral surface 430 and holding portion 46, and pressure is applied to outer peripheral surface 430 from oil 100 in the direction indicated by arrow 101. However, the portion where the outer peripheral spiral groove 43 is provided is the low pressure region 102, and the pressure applied from the oil 100 to the outer peripheral surface 430 is reduced in this portion.

  Referring to FIG. 4, when full float bearing 40 rotates from the state shown in FIG. 3, outer peripheral spiral groove 43 moves in the axial direction (right direction in FIG. 4). As a result, the low pressure region 102 also moves to the right from FIG. That is, as the full float bearing 40 rotates, the low pressure region 102 moves to the right, and the distribution of the surface pressure from the oil 100 on the outer peripheral surface 430 differs.

  Referring to FIG. 5, when the full float bearing 40 further rotates, the outer circumferential spiral groove 43 moves in the axial direction (right direction in FIG. 5). Along with this, the low pressure region 102 also moves to the right, and the surface pressure distribution of the oil 100 on the outer peripheral surface 430 sequentially changes.

  In FIG. 1, since the inner peripheral surface 420 is also provided with the inner peripheral spiral groove 42, the same change in the surface pressure distribution also occurs on the inner peripheral surface 420. That is, the portion where the inner circumferential spiral groove 42 is provided becomes a low pressure region, and the low pressure region moves as the full float bearing 40 rotates, so that the surface pressure distribution also changes on the inner circumferential surface 420. If the spiral groove is provided in at least one of the inner peripheral surface and the outer peripheral surface of the full float bearing 40 in this way, the surface pressure distribution that the full float bearing receives from the oil changes as the full float bearing 40 rotates. Therefore, the full float bearing is less likely to enter a stable state, and self-excited vibration can be suppressed.

  In the conventional turbocharger, when no groove is formed in the full float bearing 40, or even if the groove is formed, if the groove is not spiral and the axial displacement does not change, the oil is in the full float bearing. The distribution of the surface pressure applied to 40 is constant, and the full float bearing 40 rotates stably. At this time, self-excited vibration occurs due to some external input, and the turbo main body and the intake / exhaust system may also vibrate and generate abnormal noise. However, in the present invention, since the inner peripheral spiral groove 42 and the outer peripheral spiral groove 43 are provided, a difference occurs in the load capacity applied to the full float bearing 40, and the balance is slightly lost to make it difficult to enter the stable region. As a result, it is difficult for self-excited vibration to occur, and generation of abnormal noise can be suppressed.

(Embodiment 2)
6 to 9 are perspective views of a full float bearing used in the turbocharger according to the second embodiment of the present invention. With reference to FIG. 6, the inner circumferential spiral groove 42 and the outer circumferential spiral groove 43 may be provided in opposite directions. That is, in FIG. 2 of the first embodiment, the inner peripheral spiral groove 42 and the outer peripheral spiral groove 43 that rotate in the same direction are shown, but in FIG. 6, the rotation directions of the inner peripheral spiral groove 42 and the outer peripheral spiral groove 43 are different. . In FIG. 6, the outer circumferential spiral groove 43 rotates to the right while the inner circumferential spiral groove 42 rotates to the left as it approaches the upper right of the figure.

  Referring to FIG. 7, it is not necessary to provide only the outer peripheral spiral groove 43 and to provide the inner peripheral spiral groove. In this case, the rotation direction of the outer circumferential spiral groove 43 is not particularly limited.

  Referring to FIG. 8, only the inner peripheral spiral groove 42 may be provided. The rotation direction of the inner circumferential spiral groove 42 in this case is not particularly limited.

  Referring to FIG. 9, a plurality of outer peripheral spiral grooves 43 may be provided. A plurality of inner peripheral spiral grooves may be provided. A plurality of inner peripheral spiral grooves and outer peripheral spiral grooves may be provided. In FIG. 9, the two outer circumferential spiral grooves 43 are provided at a constant interval. However, when a plurality of spiral grooves are provided, these intervals may vary unevenly.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be used, for example, in the field of turbochargers mounted on vehicles.

It is sectional drawing of the turbocharger according to Embodiment 1 of this invention. It is a perspective view of the full float bearing 40 in FIG. It is a figure for demonstrating the effect | action of the full float bearing according to Embodiment 1 of this invention, Comprising: It is sectional drawing which expands and shows the part enclosed by III in FIG. It is a figure for demonstrating the effect | action of the full float bearing according to Embodiment 1 of this invention, Comprising: It is sectional drawing which expands and shows the part enclosed by III in FIG. It is a figure for demonstrating the effect | action of the full float bearing according to Embodiment 1 of this invention, Comprising: It is sectional drawing which expands and shows the part enclosed by III in FIG. It is a perspective view of the full float bearing used with the turbocharger according to Embodiment 2 of this invention. It is a perspective view of the full float bearing used with the turbocharger according to Embodiment 2 of this invention. It is a perspective view of the full float bearing used with the turbocharger according to Embodiment 2 of this invention. It is a perspective view of the full float bearing used with the turbocharger according to Embodiment 2 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Turbocharger, 10 Compressor housing, 11 Compressor, 12 Compressor housing vortex chamber, 20 Center housing, 30 Turbine housing, 31 Turbine, 32 Turbine housing vortex chamber, 40 Full float bearing, 41 Oil feed hole, 42 Inner peripheral spiral groove, 43 outer peripheral spiral groove, 46 holding portion, 49 ring member, 100 oil, 420 inner peripheral surface, 430 outer peripheral surface.

Claims (4)

A cylindrical full float bearing having an inner peripheral surface and an outer peripheral surface,
The inner peripheral surface faces the turbine shaft with fluid interposed therebetween,
The outer peripheral surface faces the holding portion with fluid interposed therebetween,
A full float bearing in which a spiral groove is provided on at least one of the inner peripheral surface and the outer peripheral surface.   The full float bearing according to claim 1, wherein the spiral groove is provided on both the inner peripheral surface and the outer peripheral surface. A turbine shaft;
A compressor and a turbine provided at both ends of the turbine shaft;
A housing having a holding portion for holding the turbine shaft;
An inner peripheral surface and an outer peripheral surface, the inner peripheral surface is opposed to the turbine shaft with fluid interposed therebetween, and the outer peripheral surface is opposed to the holding portion with fluid interposed therebetween, and a cylindrical full float bearing is provided. A supercharger with which
The supercharger provided with a spiral groove in at least one of the inner peripheral surface and the outer peripheral surface.   The supercharger according to claim 3, wherein the spiral groove is provided on both the inner peripheral surface and the outer peripheral surface.

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