JP2006083779A - Sealing structure of turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing structure of a turbocharger capable of obtaining excellent sealing property by a simple configuration. <P>SOLUTION: This sealing structure of the turbocharger is provided with a turbine shaft 21 having an outer peripheral face 21a extending along a central axis 101 and forming a seal ring channel 45 on the outer peripheral face 21a, a bearing housing 31 having an inner peripheral face 31a extending at a position where it faces the seal ring channel 45, and a seal ring 41 stored in the seal ring channel 45 by providing a clearance in the direction in which the central axis 101 is extended and having elastic force for energizing the inner peripheral face 31a. The inner peripheral face 31a is formed by inclining for the central axis 101 so that distance A from the central axis 101 to the inner peripheral face 31a is increased from one side toward the other side in the direction in which the central axis 101 is extended. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention generally relates to a seal structure for a turbocharger, and more particularly to a seal structure for a turbocharger for a vehicle.

  Regarding a conventional turbocharger seal structure, for example, Japanese Patent Application Laid-Open No. 8-28291 discloses a shaft seal structure for a turbocharger for the purpose of reducing lubricating oil leaking through a joint gap in a seal ring. (Patent Document 1). The shaft seal structure disclosed in Patent Document 1 includes a seal ring that is attached to a ring groove formed on the outer periphery of a shaft body and has a joint. The joint is formed so as to extend in the direction opposite to the rotation direction of the shaft body from the side where the bearing is disposed toward the opposite side.

  Japanese Utility Model Laid-Open No. 61-10936 discloses an oil seal device for a turbocharger for the purpose of preventing a significant increase in the consumption of lubricating oil (Patent Document 2). The oil seal device disclosed in Patent Document 2 includes two seal rings arranged side by side in a seal ring groove. In these seal rings, recesses are formed at positions facing each other, and O-rings are arranged in the recesses. By the O-ring, the side surface of the seal ring is elastically pressed against the side wall of the opposing seal ring groove.

Japanese Patent Laid-Open No. 2000-204942 discloses an exhaust pipe sealing device that aims to seal a joint portion of a pair of split exhaust pipes with good sealing properties (Patent Document 3). Further, Japanese Utility Model Laid-Open No. 5-73223 discloses a split-type exhaust manifold joint seal structure for the purpose of preventing gas leakage from the split-type exhaust manifold joint (Patent Document 4). ).
JP-A-8-28291 Japanese Utility Model Publication No. 61-10936 JP 2000-204942 A Japanese Utility Model Publication No. 5-73223

  In the turbo seal shaft sealing structure disclosed in Patent Document 1 described above, in order to prevent the lubricating oil discharged from the bearing from leaking from the joint of the seal ring, the extending direction of the joint is defined as a predetermined direction. ing. However, the lubricating oil leaks from the gap between the seal ring and the side wall of the ring groove in addition to the joint. Under an operating condition in which the shaft rotates at high speed, the seal ring is urged against the side wall of the ring groove by the gas pressure, but under a low load operating condition, the lubricating oil leaking from such a gap increases.

  On the other hand, in the turbocharger oil seal device disclosed in Patent Document 2, an O-ring having an elastic force is provided separately from the seal ring in order to bias the seal ring toward the side wall of the seal ring groove. However, in this case, the problem that the number of parts increases and the problem that the seal structure becomes complicated occur.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems, and to provide a turbocharger seal structure capable of obtaining excellent sealing performance with a simple configuration.

  The turbocharger seal structure according to the present invention has a first peripheral surface extending along a predetermined axis, and a seal ring groove is formed in the first peripheral surface along the circumferential direction. 1 member, a second member having a second peripheral surface extending at a position facing the seal ring groove, a second member rotating relative to the first member, and a predetermined axis extending in the seal ring groove And a seal ring that is accommodated in a direction (hereinafter also referred to as an axial direction) with a gap and has an elastic force that biases the second peripheral surface. The second peripheral surface is formed to be inclined with respect to the predetermined axis so that the distance from the predetermined axis to the second peripheral surface increases from one side to the other in the extending direction of the predetermined axis. ing.

  According to the turbocharger seal structure thus configured, the second peripheral surface is formed to be inclined with respect to a predetermined axis. For this reason, when the seal ring urges the second peripheral surface by its own elastic force, the seal ring has an axial force (more specifically, as a component of the reaction force received from the second peripheral surface). , A force in a direction in which the distance from the predetermined axis to the second peripheral surface moves from a relatively small side to a relatively large side) acts. As a result, the seal ring moves within the seal ring groove so as to close the gap in the axial direction with the seal ring groove, and a state where the seal ring and the side wall of the seal ring groove are in close contact with each other is obtained. Therefore, according to the present invention, the sealing performance between the first member and the second member by the seal ring can be improved without providing a complicated structure.

  Preferably, the seal ring is inclined with respect to a predetermined axis, and has a contact surface in surface contact with the second peripheral surface. According to the turbocharger sealing structure configured in this way, the contact surface of the seal ring is in surface contact with the second peripheral surface, and thus the sealing performance between the first member and the second member. Can be further improved.

  Also, on both sides of the seal ring, the first space located on the side where the distance from the predetermined axis to the second peripheral surface is relatively small, and the distance from the predetermined axis to the second peripheral surface And a second space located on the relatively large side. When the first member and the second member rotate relatively, the pressure in the first space becomes larger than the pressure in the second space. According to the turbocharger seal structure thus configured, the axial force acting on the seal ring can be increased by utilizing the pressure difference between the first space and the second space. Thereby, the sealing performance between the first member and the second member can be further improved.

  Preferably, when the first member rotates about a predetermined axis, a blade member is formed adjacent to the seal ring groove on the first peripheral surface located in the first space. . According to the turbocharger sealing structure thus configured, the blade member rotates when the first member rotates, thereby generating a flow of wind toward the seal ring in the first space. Thereby, since wind pressure is applied to the seal ring, the axial force acting on the seal ring can be increased. For this reason, the sealing performance between the first member and the second member can be further improved.

  Preferably, the seal ring has both ends overlapped with each other when received in the seal ring groove. The seal ring is accommodated in the seal ring groove so that the overlapping stitches at both ends are in contact with the side wall of the seal ring groove. According to the seal structure of the turbocharger configured as described above, it is possible to prevent the sealing performance of the seal ring from being impaired at the overlap of both ends of the seal ring.

  As described above, according to the present invention, it is possible to provide a turbocharger seal structure that provides excellent sealing performance with a simple configuration.

  Embodiments of the present invention will be described with reference to the drawings. In the drawings described below, the same or equivalent members are denoted by the same reference numerals.

(Embodiment 1)
1 is a cross-sectional view showing a turbocharger seal structure according to Embodiment 1 of the present invention. Referring to FIG. 1, a turbocharger 10 is mounted on a vehicle such as an automobile, and includes a turbine 11 provided on an engine exhaust path, a compressor 12 provided on an engine intake path, and a turbine 11. A turbine shaft 21 extending along the central axis 101. At both ends of the turbine shaft 21, turbine blades 22 are provided on the turbine 11 side, and compressor blades 23 are provided on the compressor 12 side.

  Between the turbine 11 and the compressor 12, a bearing housing 31 extending in a cylindrical shape around the turbine shaft 21 is provided. The turbine shaft 21 is rotatably provided around the central axis 101 by a journal bearing 14 fixed to the bearing housing 31. The journal bearing 14 is formed with a lubricating oil passage, and the lubricating oil is supplied between the journal bearing 14 and the turbine shaft 21 via the lubricating oil path.

  The turbocharger 10 is further provided with a thrust bearing 13 at a position between the thrust collars 17 and 18 fixed to the turbine shaft 21. A minute gap is formed between the thrust bearing 13 and the thrust collars 17 and 18. By supplying lubricating oil from the thrust bearing 13 to the gap, the turbine shaft 21 is held in the direction in which the central shaft 101 extends (hereinafter also referred to as the central shaft 101 direction).

  The operation of the turbocharger 10 will be briefly described. Air, which is mixed with fuel and burned in the engine, that is, exhaust gas, is introduced into the turbine 11 from an exhaust manifold connected to each cylinder of the engine. The exhaust gas then rotates the turbine blade 22, and the rotational force is transmitted to the turbine shaft 21. Thereafter, the exhaust gas is guided to the catalyst and discharged outside the vehicle in a purified state. On the other hand, the air taken from outside the vehicle to be supplied to the engine is filtered by an air cleaner (not shown) and then guided to the compressor 12. The air is then pressurized by a compressor blade 23 that rotates integrally with the turbine shaft 21. The pressurized air is guided to the intercooler, and is sucked into the intake manifold of the engine in a cooled state.

  2 is an enlarged cross-sectional view of a range surrounded by a two-dot chain line II in FIG. Referring to FIGS. 1 and 2, turbine shaft 21 has an outer peripheral surface 21 a extending along central axis 101. A seal ring groove 45 extending annularly around the central axis 101 is formed at a position adjacent to the turbine blade 22 on the outer peripheral surface 21a.

  The seal ring groove 45 is formed by side walls 45m and 45n facing each other at a distance in the direction of the central axis 101. The side wall 45m continues to the outer peripheral surface 21a located on the turbine blade 22 side with the seal ring groove 45 interposed therebetween, and the side wall 45n continues to the outer peripheral surface 21a located on the journal bearing 14 side. The distance between the central axis 101 and the outer peripheral surface 21a connected with the side wall 45n is larger than the distance between the central axis 101 and the outer peripheral surface 21a connected with the side wall 45m. On both sides of the seal ring groove 45, a turbine chamber 50 provided with the turbine blade 22 and a bearing chamber 55 provided with the journal bearing 14 are formed.

  The bearing housing 31 has an inner peripheral surface 31 a that faces the seal ring groove 45 and extends in an annular shape. The inner peripheral surface 31a is formed such that the distance A between the inner peripheral surface 31a and the central shaft 101 increases monotonously as it goes from the turbine chamber 50 side to the bearing chamber 55 side. That is, the inner peripheral surface 31 a is formed to be inclined with respect to the central axis 101, and is constituted by a side surface of a truncated cone that exists along the central axis 101. The inner peripheral surface 31 a may be formed such that the distance A between the inner peripheral surface 31 a and the central axis 101 increases while changing the inclination along the central axis 101.

  FIG. 3 is a perspective view showing the seal ring in FIG. 2. 2 and 3, seal ring 41 made of, for example, spring steel is arranged in seal ring groove 45. The seal ring 41 is formed in a ring shape, and has a ring tension for expanding the diameter in the direction indicated by the arrow 110 while being accommodated in the seal ring groove 45. The seal ring 41 extends in an annular shape and has a contact surface 41a that makes surface contact with the inner peripheral surface 31a. The contact surface 41a is inclined with respect to the central axis 101 with the same inclination as the inner peripheral surface 31a. The seal ring 41 is formed such that the area of the contact surface 41a is smaller than the area of the inner peripheral surface 31a. The inner peripheral surface 31 a is in pressure contact with the contact surface 41 a of the seal ring 41 due to the ring tension of the seal ring 41.

  The seal ring 41 further includes a side surface 41c that is continuous with both ends of the contact surface 41a and faces the side wall 45m of the seal ring groove 45, and a side surface 41b that faces the side wall 45n. The thickness of the seal ring 41 that is the distance from the side surface 41c to the side surface 41b is smaller than the width of the seal ring groove 45 that is the distance from the side wall 45m to the side wall 45n. That is, the seal ring 41 is arranged in the seal ring groove 45 with a gap in the direction of the central axis 101. Further, a gap is also provided between the seal ring 41 and the bottom surface of the seal ring groove 45 connected to the side wall 45m and the side wall 45n. By providing such a gap, the seal ring 41 is prevented from being seized in the seal ring groove 45.

  When the seal ring 41 urges the inner peripheral surface 31a by ring tension, the reaction force is received from the inner peripheral surface 31a. At this time, since the inner peripheral surface 31a is formed to be inclined with respect to the central axis 101, the seal ring 41 has a central axis 101 directed from the turbine chamber 50 side to the bearing chamber 55 side as a component force of the reaction force. Directional force acts. Thereby, the seal ring 41 moves to the bearing chamber 55 side, and a state in which the side surface 41b of the seal ring 41 and the side wall 45n of the seal ring groove 45 are in close contact with each other is obtained.

  When the inclination of the inner peripheral surface 31a with respect to the central axis 101 is θ, the inner peripheral surface 31a is preferably formed so as to satisfy the relationship of 15 ° ≦ θ ≦ 45 °. Since the side surface 41b of the seal ring 41 is in close contact with and rubbed with the side wall 45n of the seal ring groove 45 when the turbine shaft 21 rotates, it wears with time. As the wear of the side surface 41b proceeds, the seal ring 41 is displaced from the turbine chamber 50 side toward the bearing chamber 55 side, and at the same time, the diameter increases in the direction indicated by the arrow 110. In this case, the ratio of the diameter of the seal ring 41 to the wear of the side surface 41b increases in proportion to the inclination of the inner peripheral surface 31a. For this reason, when the inclination θ is larger than 45 °, the contact area between the side surface 41b and the side wall 45n of the seal ring groove 45 is reduced early, and the sealing performance by the seal ring 41 may be impaired. On the other hand, when the inclination θ is smaller than 15 °, the force in the direction of the central axis 101 obtained from the ring tension of the seal ring 41 becomes too small, and there is a possibility that the side surface 41b and the side wall 45n cannot be sufficiently adhered.

  Further, when the turbine shaft 21 rotates, exhaust gas continuously flows from the engine into the turbine chamber 50, so that the pressure in the turbine chamber 50 becomes larger than the pressure in the bearing chamber 55. Therefore, a force in the direction of the central axis 101 from the turbine chamber 50 side toward the bearing chamber 55 side acts on the seal ring 41, and the side surface 41b and the side wall 45b can be further adhered to each other.

  4 is a cross-sectional view of the seal ring taken along line IV-IV in FIG. The shape of the seal ring 41 will be described in more detail with reference to FIGS. 3 and 4. The seal ring 41 has end portions 41 p and 41 q that are overlapped with each other while being accommodated in the seal ring groove 45. The end portion 41q has a cross-sectional shape in which one corner of the quadrangle is cut out, and the end portion 41p has a cross-sectional shape that is fitted into the notch in the end portion 41q. When the end portion 41p and the end portion 41q are overlapped to form a joint, the side surface 41b is formed with an overlapping stitch 42 that extends a predetermined length along the circumferential direction of the seal ring 41.

  FIG. 5 is a cross-sectional view showing the turbocharger seal structure in FIG. 2 in a further enlarged manner. In the drawing, the cross-sectional position of the seal ring shown in FIG. 4 is shown. Referring to FIG. 5, the seal ring 41 is accommodated in the seal ring groove 45 so that the overlapping stitch 42 contacts the side wall 45n. With such a configuration, it is possible to prevent the sealing performance of the seal ring 41 from being impaired at the joint where the end portion 41p and the end portion 41q are overlapped.

  FIG. 6 is a perspective view showing a modified example of the seal ring in FIG. 3. FIG. 7 is a cross-sectional view showing a state in which the seal ring in FIG. 6 is accommodated in the seal ring groove. FIG. 7 shows the cross-sectional position of the seal ring along the line VII-VII in FIG. With reference to FIGS. 6 and 7, in this modification, a double seal ring structure is adopted in which seal rings 61 and 66 are combined to form one seal ring 60. The seal ring 61 has a side surface 61 b that faces the side wall 45 n of the seal ring groove 45. The seal ring 61 further has end portions 61p and 61q. Each of the end portions 61p and 61q has a cross-sectional shape obtained by dividing the cross section of the seal ring 61 into two parts. When the end portion 61p and the end portion 61q are overlapped to form a joint, the side surface 61b is formed with an overlapping stitch 62 that extends a predetermined length along the circumferential direction of the seal ring 61.

  The seal ring 66 has end portions 66p and 66q. The end surface of the end portion 66p and the end surface of the end portion 66q are brought into contact with each other to form a seal ring 66 joint. The seal ring 60 is configured by combining the seal ring 66 with the seal ring 61 from the side surface opposite to the side surface 61b. At this time, both are combined so that the joint of the seal ring 66 and the joint of the seal ring 61 are positioned at different phase positions, that is, 180 ° shifted in this embodiment.

  The seal ring 60 is accommodated in the seal ring groove 45 so that the seal rings 61 and 66 are aligned in the direction of the central axis 101. At this time, the overlapping stitch 62 of the seal ring 61 contacts the side wall 45n. With such a configuration, it is possible to obtain the same effect as when the seal ring 41 in FIG. 3 is used. In addition, in this modification, since the shapes of the end portions of the seal rings 61 and 66 constituting the joint are simple, the seal ring 60 can be manufactured more easily. Further, the joint of the seal rings 61 and 66 is positioned at a phase position shifted from each other. For this reason, the joint of one seal ring can be covered with the other seal ring, and the sealing performance can be improved.

  The seal structure of the turbocharger 10 according to Embodiment 1 of the present invention has an outer peripheral surface 21a as a first peripheral surface extending along a central axis 101 as a predetermined axis, and the outer peripheral surface 21a has its peripheral surface. A turbine shaft 21 as a first member in which a seal ring groove 45 is formed along the direction, and an inner peripheral surface 31a as a second peripheral surface extending at a position facing the seal ring groove 45; Bearing housing 31 as a second member that rotates relative to turbine shaft 21 (in the present embodiment, bearing housing 31 rotates relative to turbine shaft 21 as turbine shaft 21 rotates). And a seal ring that is accommodated in the seal ring groove 45 with a gap in the direction in which the central shaft 101 extends and has an elastic force that biases the inner peripheral surface 31a And a 41. The inner peripheral surface 31a is formed to be inclined with respect to the central axis 101 so that the distance A from the central axis 101 to the inner peripheral surface 31a increases from one to the other in the direction in which the central axis 101 extends. Yes.

  The first member is a turbine shaft 21 as a shaft member that rotates about the central axis 101, and the second member is a cylindrical member that extends along the central axis 101 around the turbine shaft 21. This is a bearing housing 31.

  The seal ring 41 is formed to be inclined with respect to the central axis 101, and has a contact surface 41a that is in surface contact with the inner peripheral surface 31a. The seal ring 41 is not limited to the shape described in the present embodiment, and may have, for example, a circular cross-sectional shape. Also in this case, the effects described below can be obtained similarly.

  Further, the seal structure of the turbocharger 10 according to the present embodiment is a seal between the bearing chamber 55 and the compressor chamber provided with the compressor blade 23 (position surrounded by a two-dot chain line 120 in FIG. 1). It can also be used. In this case, the inner peripheral surface of the housing urged by the seal ring is in relation to the central shaft 101 so that the distance from the central shaft 101 to the inner peripheral surface increases from the compressor chamber side toward the bearing chamber 55 side. It is formed to be inclined.

  According to the seal structure of the turbocharger 10 according to Embodiment 1 of the present invention configured as described above, the seal ring 41 is moved in the direction of the central axis 101 by inclining the inner peripheral surface 31a with respect to the central axis 101. The side surface 41b of the seal ring 41 and the side wall 45n of the seal ring groove 45 can be brought into close contact with each other.

  In the present embodiment, the force in the direction of the central axis 101 acting on the seal ring 41 has a magnitude corresponding to the ring tension of the seal ring 41. For this reason, unlike the case where only the pressure difference between the turbine chamber 50 and the bearing chamber 55 is relied upon, the seal ring 41 is reliably moved in the direction of the central axis 101 even when the ring tension of the seal ring 41 is large. Can be made. Further, since this force is a reaction force of the ring tension of the seal ring 41, it always acts on the seal ring 41 regardless of the operation state of the turbocharger 10. For this reason, in the present embodiment, the sealing performance by the seal ring 41 can be improved, and the lubricating oil supplied from the journal bearing 14 can be effectively prevented from leaking from the bearing chamber 55 to the turbine chamber 50.

  Further, the seal structure of the turbocharger 10 according to the present embodiment is more effectively used for vehicles such as automobiles whose operating conditions change over a wide range, compared to power generation that is operated at a substantially constant load. The The reason is as described below.

  FIG. 8 is a diagram schematically showing the gas flow in the turbocharger in FIG. Referring to FIG. 8, the pressure of the exhaust gas introduced from the engine into the turbine 11 is P1, the pressure of the exhaust gas discharged from the turbine 11 is P2, the pressure of the air introduced from the air cleaner to the compressor 12 is P3, The pressure of the air discharged from the compressor 12 is assumed to be P4. In this case, P2 and P3 are about the atmospheric pressure. Further, since the energy of the exhaust gas introduced into the turbine 11 is replaced with the rotational force of the turbine blade 22, P2 is smaller than P1 (P2 <P1). Furthermore, since the air introduced into the compressor 12 is pressurized by the rotating compressor blade 23, P4 becomes larger than P3 (P4> P3).

  The magnitude relationship between P1 and P4 varies depending on the traveling state of the vehicle on which the turbocharger 10 is mounted. That is, when the engine rotates at a high speed, the amount of exhaust gas increases, so P1 becomes larger than P4. Further, when the load is low and the engine rotates at a low speed, the amount of exhaust gas decreases, so that P4 becomes larger than P1. The pressures P1 and P4 act on the back surface 22b of the turbine blade 22 and the back surface 23b of the compressor blade 23 with almost the same magnitude, respectively.

  On the other hand, the turbine shaft 21 held in the direction of the central axis 101 by the thrust bearing 13 in FIG. 1 is provided so that a minute displacement is possible in the direction of the central axis 101. Therefore, when the engine rotates at a high speed and P1 becomes larger than P4, the turbine shaft 21 moves in the direction indicated by the arrow 141, and when the engine rotates at a low speed and P4 becomes larger than P1. The turbine shaft 21 moves in the direction indicated by the arrow 142. In other words, in the turbocharger 10 for automobiles over a wide range of operating conditions, the rotational speed of the engine constantly changes, so that the turbine shaft 21 rotates while being displaced in the direction of the central axis 101.

  However, in the seal structure of the turbocharger 10 in the present embodiment, the force in the direction of the central axis 101 continues to act on the seal ring 41 due to the ring tension of the seal ring 41. For this reason, the seal ring 41 can be made to follow the displacement of the turbine shaft 21 in the direction of the central axis 101, and the state where the side surface 41b of the seal ring 41 and the side wall 45n of the seal ring groove 45 are in close contact with each other can always be maintained. Thereby, although the turbine shaft 21 continues to be displaced in the direction of the central axis 101, excellent sealing performance by the seal ring 41 can be realized.

(Embodiment 2)
FIG. 9 is a cross-sectional view showing a turbocharger seal structure according to Embodiment 2 of the present invention. The seal structure of the turbocharger in the present embodiment is basically the same as that of the turbocharger 10 in the first embodiment. Hereinafter, the description of the overlapping structure will not be repeated.

  Referring to FIG. 9, in the present embodiment, blade member 71 is provided on outer peripheral surface 21 a of turbine shaft 21, located in turbine chamber 50. A plurality of blade members 71 are provided adjacent to the seal ring groove 45 along the circumferential direction of the outer peripheral surface 21a. The blade member 71 is formed such that wind flows from the turbine chamber 50 toward the seal ring 41 when the turbine shaft 21 rotates.

  According to the turbocharger seal structure according to the second embodiment of the present invention configured as described above, the same effects as those described in the first embodiment can be obtained. In addition, by providing the blade member 71, wind pressure applied in the direction of the central axis 101 acts on the seal ring 41. For this reason, the seal ring 41 can be moved in the direction of the central axis 101 more easily, and the sealing performance by the seal ring 41 can be further improved.

(Embodiment 3)
FIG. 10 is a cross-sectional view showing a turbocharger seal structure according to Embodiment 3 of the present invention. The seal structure of the turbocharger in the present embodiment is basically the same as that of the turbocharger 10 in the first embodiment. Hereinafter, the description of the overlapping structure will not be repeated.

  Referring to FIG. 10, in the present embodiment, a leaf spring 81 is fixed to the side surface 41 c of the seal ring 41. When the seal ring 41 is accommodated in the seal ring groove 45, the leaf spring 81 is bent between the side surface 41c and the side wall 45m of the seal ring groove. In this state, a force in the direction of the central axis 101 from the turbine chamber 50 side toward the bearing chamber 55 side acts on the seal ring 41 by the elastic force of the leaf spring 81.

  The turbocharger sealing structure according to the third embodiment of the present invention further includes a leaf spring 81 as a spring member that biases the seal ring 41 toward the side wall 45n of the seal ring groove 45.

  FIG. 11 is a cross-sectional view showing a modification of the seal structure of the turbocharger shown in FIG. Referring to FIG. 11, in this modification, a coil spring 91 is provided instead of the leaf spring 81 in FIG. In this case, a force in the direction of the central axis 101 from the turbine chamber 50 side toward the bearing chamber 55 side can also be applied to the seal ring 41 by the elastic force of the coil spring 91.

  According to the turbocharger seal structure according to the third embodiment of the present invention configured as described above, the same effects as those described in the first embodiment can be obtained. In addition, by providing the leaf spring 81 and the coil spring 91, the elastic force of these springs can be applied to the seal ring 41. Thereby, the seal ring 41 can be moved more easily in the direction of the central axis 101, and the sealing performance by the seal ring 41 can be further improved.

  In the turbocharger seal structure according to the first to third embodiments, the case where the seal ring groove 45 is formed in the turbine shaft 21 has been described. However, the seal ring groove 45 is formed on the inner peripheral surface of the bearing housing 31. It may be formed. In this case, the outer peripheral surface of the turbine shaft 21 extending at a position facing the inner peripheral surface is such that the distance from the central axis 101 to the outer peripheral surface increases from one to the other in the direction in which the central axis 101 extends. Further, it is formed to be inclined with respect to the central axis 101. A seal ring having an elastic force that biases the outer peripheral surface of the turbine shaft 21 is disposed in a seal ring groove formed on the inner peripheral surface of the bearing housing 31.

  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.

It is sectional drawing which shows the seal structure of the turbocharger in Embodiment 1 of this invention. It is sectional drawing which expands and shows the range enclosed by the dashed-two dotted line II in FIG. It is a perspective view which shows the seal ring in FIG. It is sectional drawing of the seal ring along the IV-IV line in FIG. FIG. 3 is a cross-sectional view further enlarging the seal structure of the turbocharger in FIG. 2. It is a perspective view which shows the modification of the seal ring in FIG. It is sectional drawing which shows the state in which the seal ring in FIG. 6 was accommodated in the seal ring groove. It is the figure which represented typically the gas flow in the turbocharger in FIG. It is sectional drawing which shows the seal structure of the turbocharger in Embodiment 2 of this invention. It is sectional drawing which shows the seal structure of the turbocharger in Embodiment 3 of this invention. It is sectional drawing which shows the modification of the seal structure of the turbocharger shown in FIG.

Explanation of symbols

  10 turbocharger, 21 turbine shaft, 21a outer peripheral surface, 31 bearing housing, 31a inner peripheral surface, 41 seal ring, 41a contact surface, 45 seal ring groove, 45n side wall, 50 turbine chamber, 55 bearing chamber, 71 blade member, 101 Central axis.

Claims (5)

A first member having a first peripheral surface extending along a predetermined axis and having a seal ring groove formed along the circumferential direction on the first peripheral surface;
A second member having a second peripheral surface extending at a position facing the seal ring groove, and rotating relative to the first member;
A seal ring that is accommodated in the seal ring groove with a gap in a direction in which the predetermined axis extends and has an elastic force that biases the second peripheral surface;
The second peripheral surface with respect to the predetermined axis so that a distance from the predetermined axis to the second peripheral surface increases from one side to the other in the extending direction of the predetermined axis. The turbocharger seal structure is inclined.   2. The turbocharger sealing structure according to claim 1, wherein the seal ring is formed to be inclined with respect to the predetermined axis and has a contact surface in surface contact with the second peripheral surface. On both sides of the seal ring, a first space located on the side where the distance from the predetermined axis to the second peripheral surface is relatively small, and the second peripheral surface from the predetermined axis And a second space located on the side where the distance to is relatively large,
The pressure in the first space is larger than the pressure in the second space when the first member and the second member are relatively rotated. Turbocharger seal structure.   When the first member rotates about the predetermined axis, a blade member is formed adjacent to the seal ring groove on the first peripheral surface located in the first space. The turbocharger seal structure according to claim 3. The seal ring has both ends overlapped with each other when accommodated in the seal ring groove;
The turbocharger according to any one of claims 1 to 4, wherein the seal ring is accommodated in the seal ring groove so that a lap of the both ends contacts a side wall of the seal ring groove. Seal structure.

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