JP4816562B2 - Oil seal structure - Google Patents

Description

  The present invention relates to an oil seal structure, and more particularly to an oil seal structure for a supercharger.

  A turbocharger used in an internal combustion engine has a structure in which a turbine and a compressor are connected by a rotating shaft and rotate integrally. As a bearing system for supporting the rotating shaft used in such a supercharger, for example, a bearing system that requires lubricating oil is used. This lubricating oil is sealed by a seal ring provided between the bearing housing and the rotating shaft.

  Since such a seal ring seals the lubricating oil while sliding with the cylindrical portion of the rotating shaft, it wears with the rotation of the rotating shaft. When the seal ring is worn, the seal ring moves in the axial direction of the rotating shaft by an external force such as exhaust gas. In Patent Document 1, in an oil seal structure using one seal ring, a seal structure in which a stopper member for restricting movement of the seal ring in the axial center direction is attached to the inner peripheral surface of the bearing housing by press-fitting. It is disclosed.

JP 2006-22791 A

  In recent years, as the output of an internal combustion engine increases, the exhaust gas pressure supplied to the turbine side inlet tends to increase. However, the seal ring has a joint for insertion into the rotating shaft. Therefore, it is difficult to completely prevent fluid leakage from the joint by only arranging one seal ring. Thus, a technique is used in which two seal rings are arranged on the inner peripheral surface of the bearing housing on the turbine side.

  Fig.1 (a) is typical sectional drawing which shows the prior art example of the oil seal structure used for the turbine side. As shown in FIG. 1A, a supercharger 100 includes a turbine 10, a rotating shaft 20 connected to the turbine 10, and a compressor (not shown) connected to an end surface of the rotating shaft 20 opposite to the turbine 10. And a bearing 40 that supports the rotating shaft 20, a bearing housing 50, a first seal ring 60, and a second seal ring 70. Lubricating oil for the bearing 40 is supplied to the bearing 40 through an oil passage 51 formed in the bearing housing 50. In order to seal the lubricating oil, the first seal ring 60 and the second seal ring 70 are disposed on the cylindrical inner surface portion 57 of the inner peripheral surface of the bearing housing 50 on the turbine 10 side.

  Each of the first seal ring 60 and the second seal ring 70 is made of a ring-shaped elastic member, and is inserted into the first seal ring groove 24 and the second seal ring groove 26 formed on the rotating shaft. It is in pressure contact with the cylindrical inner surface 57 of the bearing housing 50. Further, the first seal ring 60 and the second seal ring 70 are respectively provided on the side surface 23a of the first cylindrical portion 23 formed on the rotary shaft 20 by the pressure of the exhaust gas flowing from the gap between the rotary shaft 20 and the bearing housing 50. And it is press-contacted to the side surface 25a of the 2nd cylindrical part 25. FIG. Thereby, the lubricating oil supplied to the bearing 40 is sealed.

  However, since the rotating shaft 20 rotates at high speed, the first cylindrical portion 23 and the second cylindrical portion 25 also rotate at high speed. Thereby, the first seal ring 60 and the second seal ring 70 are worn. FIG. 1B is a schematic cross-sectional view showing a state where the first seal ring 60 and the second seal ring 70 are worn. As shown in FIG. 1B, the first seal ring 60 and the second seal ring 70 move in the direction opposite to the turbine 10 while the contact surfaces with the side surface 23a and the side surface 25a wear. Here, in the conventional example, a protruding portion 54 is provided in the vicinity of the cylindrical inner surface portion 57 facing the first cylindrical portion 23. Thereby, the wear of the first seal ring 60 is stopped when the first seal ring 60 comes into contact with the side surface 54a of the protrusion 54. On the other hand, the wear of the second seal ring 70 proceeds without stopping because the portion corresponding to the protrusion 54 is not provided. In this case, the oil seal performance of the second seal ring 70 is degraded.

  When the oil seal performance of the second seal ring 70 is deteriorated, the exhaust gas supplied to the turbine 10 side may flow into the vicinity of the bearing 40. If the exhaust gas flows into the vicinity of the bearing 40, the lubricating oil in the vicinity of the bearing 40 may leak into an oil pan (not shown) of the internal combustion engine. In this case, the blow-by gas amount of the internal combustion engine may increase. Further, in the technique according to Patent Document 1, a technique related to an oil seal structure when one seal ring is used is disclosed, but a technique related to an oil seal structure when two seal rings are used is not disclosed. .

  An object of the present invention is to provide an oil seal structure capable of suppressing wear of a seal ring.

An oil seal structure according to the present invention is an oil seal structure used in a supercharger that includes a turbine that is rotated by exhaust pressure of an internal combustion engine, a rotating shaft that is connected to the turbine, and a bearing housing through which the rotating shaft is inserted. The rotating shaft has a cylindrical portion that protrudes toward the bearing housing, and is disposed on the opposite side of the cylindrical portion from the turbine side of the inner peripheral surface of the bearing housing near the turbine. A first seal ring that seals between the rotating shaft and the bearing housing, and a second seal ring that is disposed closer to the turbine side than the first seal ring and the cylindrical portion on the inner peripheral surface of the bearing housing, and seals between the rotating shaft and the bearing housing , Formed on the inner peripheral surface of the bearing housing and restricting the movement of the first seal ring to the opposite side of the turbine And a stopper member that is disposed between the first seal ring and the second seal ring on the inner peripheral surface of the bearing housing and restricts the movement of the second seal ring toward the first seal ring. The first seal ring has a first joint portion at one circumferential position, the second seal ring has a second joint portion at one circumferential direction, and the stopper member has a ring shape. and, wherein the first sealing ring side of the both end faces in the central axis direction of the stopper member first mating portion projecting to fit the first abutment portion is formed, the second seal ring A second fitting portion protruding so as to be fitted to the second joint portion is formed on the side. According to the oil seal structure of the present invention, the movement of the first seal ring to the side opposite to the turbine is restricted by the protrusion. Thereby, wear of the first seal ring is suppressed. Moreover, the movement of the second seal ring toward the first seal ring is restricted by the stopper member. Thereby, wear of the second seal ring is suppressed. In addition, since the first joint portion of the first seal ring and the second joint portion of the second seal ring are respectively fitted by the first fitting portion and the second fitting portion of the stopper member, the first joint portion It is possible to suppress the leakage of lubricating oil by the part and the second joint part.

In the above configuration, an angle formed by a line connecting the central axis of the stopper member and the first fitting part and a line connecting the central axis and the second fitting part may be 90 degrees or 180 degrees. preferable. According to this configuration, the angle formed by the first joint part and the second joint part is 0 degree, that is, compared to the case where the first joint part and the second joint part are arranged at the same position in the circumferential direction. Lubricant leakage can be further suppressed. In the above configuration, it is preferable that the stopper member is disposed on the inner peripheral surface of the bearing housing by a clearance fit. According to this configuration, the stopper member can be easily arranged on the inner peripheral surface of the bearing housing.

  ADVANTAGE OF THE INVENTION According to this invention, the oil seal structure which can suppress wear of a seal ring can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 2 is a schematic cross-sectional view showing the overall configuration of the turbine side oil seal structure of the supercharger 110 according to the first embodiment. First, the overall configuration of the supercharger 110 will be described, and then the configuration of the oil seal structure will be described. First, as shown in FIG. 2, the supercharger 110 is provided on the turbine 10 that is rotated by the exhaust pressure of the internal combustion engine, the rotating shaft 20 that is connected to the turbine 10, and the end surface of the rotating shaft 20 opposite to the turbine 10. The compressor (not shown) connected, the bearing 40 which supports the rotating shaft 20, the snap rings 42 and 44 holding the bearing 40, and the bearing housing 50 through which the rotating shaft 20 is inserted are provided.

  Since the turbine 10 is exposed to the high temperature of the exhaust gas, the turbine 10 is formed of, for example, a heat-resistant nickel alloy or ceramic. In order to suppress the turbo lag, the compressor is formed of, for example, a lightweight aluminum alloy. The turbine 10 and the compressor are rotatably connected by a metal rotating shaft 20. Thereby, the rotating shaft 20 and the compressor rotate as the turbine 10 rotates.

  The rotary shaft 20 is inserted through a metal bearing housing 50. More specifically, the bearing 40 is inserted in the bearing housing 50. As the bearing 40, for example, a floating bearing can be used. In this case, the bearing 40 is held at a predetermined position of the bearing housing 50 by the snap rings 42 and 44. The bearing 40 is formed with an oil supply hole 40 a penetrating from the outer peripheral surface of the bearing 40 to the inner peripheral surface. Lubricating oil is supplied to the outer peripheral surface of the bearing 40 from an oil passage 51 formed in the bearing housing 50. The lubricating oil supplied to the outer peripheral surface of the bearing 40 is also supplied to the inner peripheral surface of the bearing 40 through the oil supply hole 40 a of the bearing 40. In this case, an oil film is formed between the inner peripheral surface of the bearing 40 and the outer peripheral surface of the rotary shaft 20. Thereby, the rotating shaft 20 is rotatably supported by the bearing 40. The bearings 40 are provided at both ends in the longitudinal direction of the rotating shaft 20, that is, near the turbine 10 and near the compressor.

  The oil passage 51 formed in the bearing housing 50 is supplied with oil for piston lubrication of the internal combustion engine. An oil drain (not shown) for discharging the lubricating oil supplied to the bearing 40 from the inside of the bearing housing 50 is provided below the bearing housing 50 in the gravity direction. The lubricating oil discharged from the oil drain is collected by an oil pan (not shown).

  Next, the structure of the oil seal structure which is a characteristic part of the present embodiment will be described. As shown in FIG. 2, the slinger 21, the slinger groove 22, the first cylindrical portion 23, and the first seal ring groove are formed on the outer peripheral surface of the rotary shaft 20 near the turbine 10 from the vicinity of the bearing 40 to the vicinity of the turbine 10. 24, a second cylindrical portion 25, and a second seal ring groove 26 are formed.

  The slinger 21 is formed closer to the turbine 10 than the portion of the rotating shaft 20 that is supported by the bearing 40. The outer shape of the slinger 21 is larger than the outer shape of the portion supported by the bearing 40 of the rotating shaft 20. The slinger 21 mainly has a function of suppressing foreign matter from entering the bearing 40 by rotating together with the rotary shaft 20.

  The slinger groove 22 is constituted by a recessed portion formed over the circumferential direction of the rotary shaft 20. The first seal ring groove 24 and the second seal ring groove 26 are configured by recessed portions formed over the circumferential direction of the rotary shaft 20. A first cylindrical portion 23 having a predetermined outer dimension is formed between the slinger groove 22 and the first seal ring groove 24. In addition, a second cylindrical portion 25 having a predetermined outer dimension is formed between the first seal ring groove 24 and the second seal ring groove 26.

  On the other hand, a recess 52, a protrusion 54, an annular groove 56, and a cylindrical inner surface 57 are formed on the inner peripheral surface of the bearing housing 50 near the turbine 10 from the vicinity of the bearing 40 to the vicinity of the turbine 10. Yes. The recessed portion 52 is formed on the inner peripheral surface of the bearing housing 50 facing the slinger 21, and is formed by a recessed portion formed along the circumferential direction of the inner peripheral surface of the bearing housing 50.

  The protrusion 54 is formed on the inner peripheral surface of the bearing housing 50 that faces the first cylindrical portion 23. Specifically, the protrusion 54 is formed such that the side surface 54 a on the turbine 10 side of the protrusion 54 is located on the compressor side (the opposite side to the turbine 10 side) than the side surface 23 a on the turbine 10 side of the first cylindrical portion 23. Has been. Further, the inner diameter of the inner peripheral surface of the protruding portion 54 is smaller than the inner diameter of the cylindrical inner surface portion 57. The protrusion 54 has a function of restricting movement of the first seal ring 60 described later to the opposite side of the turbine 10.

  The annular groove 56 is formed between the protrusion 54 and the cylindrical inner surface 57. The annular groove 56 is constituted by a recessed portion formed over the circumferential direction of the inner peripheral surface of the bearing housing 50. The annular groove 56 is formed so that a first seal ring 60 to be described later abuts on the side surface 54a of the protrusion 54 stably. Specifically, when the annular groove 56 is not formed, the corner portion between the projection 54 and the cylindrical inner surface portion 57 is difficult to cut into a right-angle shape by cutting, and therefore a curved surface (hereinafter referred to as a corner). It will be formed as a curved surface portion). In this case, the first seal ring 60 may ride on the corner curved surface portion when receiving the pressure of the exhaust gas. In this case, the first seal ring 60 cannot stably contact the side surface 54a. Therefore, the provision of the annular groove 56 prevents the first seal ring 60 from climbing onto the corner curved surface portion. The width and depth of the annular groove 56 are not particularly limited.

  The cylindrical inner surface portion 57 is formed on the inner peripheral surface of the bearing housing 50 that opposes the first seal ring groove 24, the second cylindrical portion 25, the second seal ring groove 26, and the turbine 10. Has been. A tapered portion 58 is formed at the end of the cylindrical inner surface portion 57 on the turbine 10 side. Thereby, interference with the bearing housing 50 at the end of the cylindrical inner surface portion 57 is prevented.

  A first seal ring 60, a stopper member 80, and a second seal ring 70 are sequentially arranged on the cylindrical inner surface portion 57 of the bearing housing 50 from the protruding portion 54 side to the tapered portion 58 side. Specifically, the first seal ring 60 is disposed in the cylindrical inner surface portion 57 at a position facing the first seal ring groove 24. Further, the second seal ring 70 is disposed at a position facing the second seal ring groove 26 in the cylindrical inner surface portion 57. The stopper member 80 is disposed at a position facing the second cylindrical portion 25 in the cylindrical inner surface portion 57.

  FIG. 3 is a schematic three-dimensional view showing the shapes of the first seal ring 60, the stopper member 80, and the second seal ring 70. As shown in FIG. 3, the first seal ring 60 has a ring shape in which a first joint portion 60 a is formed at one place in the circumferential direction. The second seal ring 70 has a ring shape in which a second joint portion 70a is formed at one place in the circumferential direction. The stopper member 80 has a ring shape. Further, a first fitting portion 80a protruding so as to be fitted to the first joint portion 60a is formed on the first seal ring 60 side of both end faces in the central axis direction of the stopper member 80, and the second seal ring is formed. A second fitting portion 80b is formed on the 70 side so as to protrude so as to fit into the second joint portion 70a. The angle formed between the line connecting the central axis of the stopper member 80 and the first fitting portion 80a and the line connecting the central axis of the stopper member 80 and the second fitting portion 80b is 180 degrees.

  2 and 3, the first seal ring 60, the stopper member 80, and the second seal ring 70 are arranged on the rotating shaft 20 in the order of the second seal ring 70, the stopper member 80, and the first seal ring 60. It is inserted from the side opposite to the turbine 10 (compressor side). Next, the first fitting portion 80a is fitted to the first fitting portion 60a, and the second fitting portion 80b is fitted to the second fitting portion 70a. Next, the rotary shaft 20 is inserted into the bearing housing 50. Thereby, as shown in FIG. 2, the first seal ring 60, the stopper member 80, and the second seal ring 70 can be arranged at predetermined positions on the cylindrical inner surface portion 57 of the bearing housing 50. In addition, after the rotating shaft 20 is inserted into the bearing housing 50, the turbocharger 110 is completed by assembling the turbine 10 and the compressor to the rotating shaft 20.

  In addition, as the 1st seal ring 60 and the 2nd seal ring 70, steel, stainless steel, etc. can be used, for example. The stopper member 80 is preferably made of a material having a lower hardness than the first seal ring 60 and the second seal ring 70. This is because wear of the stopper member 80 due to sliding with the first seal ring 60 and the second seal ring 70 can be suppressed. As the stopper member 80, for example, steel, stainless steel, heat resistant resin, or the like having a lower hardness than the first seal ring 60 and the second seal ring 70 can be used.

  Further, as shown in FIG. 2, the first seal ring 60 is disposed on the cylindrical inner surface portion 57 of the bearing housing 50 in a reduced diameter state. Thereby, the first seal ring 60 is expanded in diameter by its own external tension after being arranged on the cylindrical inner surface portion 57. In this case, the outer peripheral surface of the first seal ring 60 is in close contact with the cylindrical inner surface portion 57. Further, the inner diameter of the first seal ring 60 in a state where the first seal ring 60 is disposed on the cylindrical inner surface portion 57 is smaller than the outer shape of the first cylindrical portion 23, and the inner peripheral surface of the first seal ring 60 is There is a gap between the seal ring groove 24 and the seal ring groove 24. Further, the width of the first seal ring 60 in the central axis direction is smaller than the width of the first seal ring groove 24 in the central axis direction.

  Further, the second seal ring 70 is disposed on the cylindrical inner surface portion 57 of the bearing housing 50 in a reduced diameter state. Thereby, after the second seal ring 70 is arranged on the cylindrical inner surface portion 57, the diameter of the second seal ring 70 is expanded by its own external tension. In this case, the outer peripheral surface of the second seal ring 70 is in close contact with the inner surface of the cylindrical inner surface portion 57. In addition, the inner diameter of the second seal ring 70 in a state where the second seal ring 70 is disposed on the cylindrical inner surface portion 57 is smaller than the outer shape of the second cylindrical portion 25, and the inner peripheral surface of the second seal ring 70 and the second inner surface. There is a gap between the two seal ring grooves 26. Further, the width of the second seal ring 70 in the central axis direction is smaller than the width of the second seal ring groove 26 in the central axis direction.

  The stopper member 80 is preferably set to have an outer dimension slightly smaller than an inner diameter dimension of the cylindrical inner surface portion 57 of the bearing housing 50. That is, the stopper member 80 is preferably disposed on the cylindrical inner surface portion 57 by a clearance fit. This is because the stopper member 80 can be easily disposed on the cylindrical inner surface portion 57. Further, the inner diameter of the inner peripheral surface of the stopper member 80 is larger than the outer dimension of the second cylindrical portion 25. The width of the stopper member 80 in the central axis direction is approximately the same as the width of the second cylindrical portion 25 in the central axis direction.

  With the above configuration, for example, when receiving the pressure of exhaust gas from an internal combustion engine, the first seal ring 60 and the second seal ring 70 try to move in the direction of the central axis opposite to the turbine 10. Thereby, the first seal ring 60 is pressed against the side surface 23 a of the first cylindrical portion 23 on the turbine 10 side. The second seal ring 70 is pressed against the side surface 25a of the second cylindrical portion 25 on the turbine 10 side. The outer peripheral surface of the first seal ring 60 and the cylindrical inner surface portion 57 are in close contact with each other, and the outer peripheral surface of the second seal ring 70 and the cylindrical inner surface portion 57 are in close contact with each other. Thereby, the space between the rotating shaft 20 and the bearing housing 50 can be sealed.

  In addition, as shown in FIG. 3, the first joint portion 60 a of the first seal ring 60 is fitted by the first fitting portion 80 a of the stopper member 80. Further, the second joint portion 70 a of the second seal ring 70 is fitted by the second fitting portion 80 b of the stopper member 80. Thereby, the lubricating oil leakage by the 1st joint part 60a and the 2nd joint part 70a can be suppressed.

  Further, the angle formed by the line connecting the central axis of the stopper member 80 and the first fitting portion 80a and the line connecting the central axis of the stopper member 80 and the second fitting portion 80b is 180 degrees. In this case, the angle formed is 0 degree, that is, the first joint portion 60a and the second joint portion 70a are compared with the case where the first joint portion 60a and the second joint portion 70a are arranged at the same position in the circumferential direction. It is possible to further suppress the leakage of the lubricating oil.

  Further, when the rotary shaft 20 rotates, the contact portion between the first seal ring 60 and the side surface 23a of the first cylindrical portion 23 and the contact portion between the second seal ring 70 and the side surface 25a of the second cylindrical portion 25 are Wear out. FIG. 4 is a schematic cross-sectional view showing a state where the wear of the first seal ring 60 and the second seal ring 70 has progressed slightly. As shown in FIG. 4, each of the first seal ring 60 and the second seal ring 70 moves in the direction opposite to the turbine 10 while being slightly worn by being pressed by the exhaust gas pressure.

  However, a protrusion 54 is formed on the bearing housing 50. In this case, the movement of the first seal ring 60 to the side opposite to the turbine 10 is restricted by the first seal ring 60 coming into contact with the side surface 54 a of the protrusion 54. Thereby, the wear of the first seal ring 60 is suppressed. A stopper member 80 is disposed on the cylindrical inner surface portion 57 of the bearing housing 50. In this case, when the stopper member 80 is sandwiched between the first seal ring 60 and the second seal ring 70, the movement of the second seal ring 70 to the side opposite to the turbine 10 is restricted. That is, the stopper member 80 has a function of restricting the movement of the second seal ring 70 toward the first seal ring 60 side. Thereby, the wear of the second seal ring 70 is suppressed.

  In FIG. 3, the angle between the line connecting the central axis of the stopper member 80 and the first fitting portion 80a and the line connecting the central axis of the stopper member 80 and the second fitting portion 80b is 90 degrees. May be.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

It is typical sectional drawing which shows the oil seal structure by the side of the turbine of the supercharger which concerns on the prior art example of this invention. It is a typical sectional view showing the whole oil seal structure of the turbine side of the supercharger concerning the 1st example. It is a typical solid figure which shows the structure of the 1st seal ring which concerns on 1st Example, a stopper member, and a 2nd seal ring. It is a typical sectional view showing the state where abrasion of the 1st seal ring and the 2nd seal ring concerning a 1st example advanced a little.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Turbine 20 Rotating shaft 40 Bearing 50 Bearing housing 54 Protrusion part 60 1st seal ring 70 2nd seal ring 80 Stopper member 100,110 Supercharger

Claims (3)

An oil seal structure used in a turbocharger comprising a turbine that is rotated by exhaust pressure of an internal combustion engine, a rotating shaft connected to the turbine, and a bearing housing through which the rotating shaft is inserted,
The rotating shaft is formed with a cylindrical portion protruding toward the bearing housing,
A first seal ring that is disposed on the opposite side of the cylindrical portion from the turbine side of the inner peripheral surface of the bearing housing near the turbine, and seals between the rotating shaft and the bearing housing;
A second seal ring that is disposed on the turbine side of the inner peripheral surface of the bearing housing relative to the first seal ring and the cylindrical portion, and seals between the rotating shaft and the bearing housing;
A protrusion formed on the inner peripheral surface of the bearing housing for restricting the movement of the first seal ring to the opposite side of the turbine;
A stopper member disposed between the first seal ring and the second seal ring on the inner peripheral surface of the bearing housing and restricting the movement of the second seal ring toward the first seal ring; Prepared,
The first seal ring has a first joint part at one place in the circumferential direction, and the second seal ring has a second joint part at one place in the circumferential direction,
The stopper member has a ring shape, and a first fitting portion protruding so as to be fitted to the first abutment portion is provided on the first seal ring side of both end faces in the central axis direction of the stopper member. An oil seal structure, characterized in that a second fitting portion is formed and formed on the second seal ring side so as to protrude into the second joint portion.   An angle formed between a line connecting the central axis of the stopper member and the first fitting portion and a line connecting the central axis and the second fitting portion is 90 degrees or 180 degrees. The oil seal structure according to claim 1. 3. The oil seal structure according to claim 1, wherein the stopper member is disposed by clearance fitting on the inner peripheral surface of the bearing housing.

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