Patent ID: 12203378

DETAILED DESCRIPTION

An example turbocharger may include a turbine housing accommodating a turbine wheel, a bearing housing rotatably supporting a rotating shaft to which the turbine wheel is fixed, a variable geometry mechanism accommodated in the turbine housing, surrounding the turbine wheel, and configured to guide a fluid to the turbine wheel, and a spring member held by the variable geometry mechanism and the bearing housing in an axial direction along the rotating shaft. The variable geometry mechanism has an inner circumferential portion surrounding a through hole in which the turbine wheel or the rotating shaft is disposed, and an outer circumferential portion distanced further away from an axis of the rotating shaft than the inner circumferential portion. The outer circumferential portion includes a first end face contacting the spring member, and a second end face disposed on a back side of the first end face and contacting the turbine housing.

In some examples, the spring member presses the first end face of the outer circumferential portion of the variable geometry mechanism. In the variable geometry mechanism, the second end face disposed on the back side of the first end face is pressed against the turbine housing. A pressing force of the spring member is applied to the first end face, so that a reaction force is applied to the second end face disposed on the back side of the first end face. The turbocharger is thus configured to suppress the generation of bending stress in the variable geometry mechanism. Consequently, the reliability of the turbocharger improves.

In some examples, the outer circumferential portion may further include an outer circumferential face portion connecting the first end face to the second end face. The turbine housing may have an inner circumferential face portion facing the outer circumferential face portion. An inner diameter of the inner circumferential face portion may be greater than an outer diameter of the outer circumferential face portion. When the variable geometry mechanism linearly expands due to high temperature, the gap between the outer diameter of the outer circumferential face portion and the inner diameter of the inner circumferential face portion allows deformation due to linear expansion along a radial direction intersecting the rotating shaft of the variable geometry mechanism. The reliability of the turbocharger thus improves.

In some examples, the turbocharger may include an auxiliary spring member disposed between the variable geometry mechanism and the bearing housing in the axial direction along the rotating shaft. The turbocharger is configured to distribute the force applied to the variable geometry mechanism. The reliability of the turbocharger thus improves.

In some examples, the bearing housing may have a first abutting face facing the axial direction along the rotating shaft. The turbine housing may have a second abutting face abutting against the first abutting face of the bearing housing. The position at which the second abutting face abuts against the first abutting face may be outward of the spring member in the radial direction intersecting the rotating shaft. The compression of the spring member is determined on the basis of the position of the first abutting face along the axial direction along the rotating shaft and the position of the second abutting face. The spring member is thus configured to apply a pressing force to the variable geometry mechanism. Consequently, the deformation of the variable geometry mechanism of the turbocharger can be suppressed.

In some examples, the spring member may be held by the first end face and the first abutting face. The position of the first abutting face is configured to be flush with the position of a surface that holds the spring member in the axial direction along the rotating shaft. The compression of the spring member of the turbocharger can thus be managed. Consequently, the deformation of the variable geometry mechanism of the turbocharger can be suppressed.

In some examples, the variable geometry mechanism may have a nozzle ring facing the bearing housing in the axial direction along the rotating shaft. The nozzle ring may have an inner circumferential portion and an outer circumferential portion.

The example turbocharger will be described in detail below with reference to the accompanying drawings. Hereinafter, with reference to the drawings, the same elements or similar elements having the same function are denoted by the same reference numerals, and redundant description will be omitted.

An example turbocharger1illustrated inFIG.1is a variable geometry turbocharger. The turbocharger1is applied, for example, to an internal combustion engine of a ship or a vehicle. The turbocharger1has a turbine10and a compressor20. The turbine10has a turbine housing11, a turbine wheel12, and a variable geometry mechanism30. The turbine housing11has a scroll channel13. The scroll channel13is disposed around the turbine wheel12. The scroll channel13extends in a circumferential direction about a rotational axis AX. In the description below, the circumferential direction about the rotational axis AX is referred to simply as the “circumferential direction.” The compressor20has a compressor housing21and a compressor wheel22. The compressor wheel22is accommodated in the compressor housing21. The compressor housing21has a scroll channel23. The scroll channel23is disposed around the compressor wheel22. The scroll channel23extends in the circumferential direction.

The turbine wheel12is fixed to a first end of a rotating shaft2. The turbine housing11accommodates the turbine wheel12. The compressor wheel22is fixed to a second end of the rotating shaft2. A bearing housing3is provided between the turbine housing11and the compressor housing21. The rotating shaft2is rotatably supported by the bearing housing3via a bearing4. The rotating shaft2, the turbine wheel12, and the compressor wheel22constitute a unitary rotor. The rotor rotates about the rotational axis AX of the rotating shaft2.

The turbine housing11has an inlet and an outlet14. The exhaust gas discharged from the internal combustion engine enters the turbine housing11after passing through the inlet. The exhaust gas enters the turbine wheel12after passing through the scroll channel13. The exhaust gas entering the turbine wheel12rotates the turbine wheel12. After rotating the turbine wheel12, the exhaust gas flows outside the turbine housing11after passing through the outlet14.

The compressor housing21has an inlet port24and an outlet port. The compressor wheel22rotates along with the rotation of the turbine wheel12via the rotating shaft2. The rotating compressor wheel22sucks in outside air that has passed through the inlet port24. The air sucked in is compressed while passing through the compressor wheel22and the scroll channel23. The compressed air is discharged from the outlet port. The compressed air is supplied to the internal combustion engine.

The turbine10has a connection channel S. The connection channel S guides the exhaust gas from the scroll channel13to the turbine wheel12. The turbine10has the variable geometry mechanism30. The variable geometry mechanism30adjusts a cross-sectional area of the connection channel S. The variable geometry mechanism30adjusts a cross-sectional area of the connection channel S. The flow rate of the exhaust gas supplied to the turbine wheel12from the scroll channel13is controlled by adjusting the cross-sectional area of the connection channel S. The variable geometry mechanism30is thus configured to control the number of revolutions of the turbine wheel12to a predetermined or set value.

The variable geometry mechanism30is accommodated in the turbine housing11. The variable geometry mechanism30surrounds the turbine wheel12. The variable geometry mechanism30guides the exhaust gas (fluid) to the turbine wheel12. The variable geometry mechanism30has a ring-like shape about the rotational axis AX. The variable geometry mechanism30has a through hole30h. The variable geometry mechanism30surrounds the turbine wheel12disposed in the through hole30hin the circumferential direction. The variable geometry mechanism30is disposed between the scroll channel13and the outlet14.

As illustrated inFIG.2, the variable geometry mechanism30has a clearance control (CC) plate31, a nozzle ring32, a plurality of nozzle vanes33, and a drive mechanism34. The CC plate31and the nozzle ring32also have a ring-like shape about the rotational axis AX similarly to the variable geometry mechanism30. The CC plate31and the nozzle ring32constitute a part of the external shape of the variable geometry mechanism30. The CC plate31is disposed parallel to the nozzle ring32in an axial direction along the rotational axis AX. In the description below, the axial direction along the rotational axis AX is referred to simply as the “axial direction.” The distance between the CC plate31and the nozzle ring32is maintained by a CC pin. The CC plate31faces the nozzle ring32. The nozzle ring32is located closer to the bearing housing3than the CC plate31in the axial direction. The connection channel S is formed between the CC plate31and the nozzle ring32.

The nozzle ring32has an inner circumferential portion35and an outer circumferential portion36. The inner circumferential portion35surrounds a through hole32hin the nozzle ring32. The turbine wheel12and the rotating shaft2are disposed in the through hole32h. The inner circumferential portion35is an inner circumferential part of the nozzle ring32. For example, shafts of the nozzle vanes33are disposed in the through hole. Additionally, the inner circumferential portion35may be defined as an inner side of a reference circle in which the through hole is disposed. The distance of the outer circumferential portion36from the rotational axis AX is greater than that of the inner circumferential portion35. The outer circumferential portion36is an outer circumferential part of the nozzle ring32. For example, the shafts of the nozzle vanes33are disposed in the through hole. Additionally, the outer circumferential portion36may be defined as an outer side of a reference circle in which the through hole is disposed. An outer diameter of the nozzle ring32is defined by an outer diameter of the outer circumferential portion36.

The plurality of nozzle vanes33is disposed between the CC plate31and the nozzle ring32. The nozzle vanes33are disposed equidistant from each other on a reference circle about the rotational axis AX. Adjacent nozzle vanes33constitute a nozzle. Each of the nozzle vanes33rotate about an axis parallel to the rotational axis AX. The rotations of the nozzle vanes33are synchronized. The rotations of the nozzle vanes33cause the distance between adjacent nozzle vanes33to change. The distance between the adjacent nozzle vanes33correspond to the cross-sectional area of the connection channel S. In some examples, the cross-sectional area of the connection channel S is adjusted by the change in the distance between the adjacent nozzle vanes33.

The drive mechanism34is disposed between the nozzle ring32and the bearing housing3. The drive mechanism34has a drive ring34aand a nozzle link plate34b. The drive ring34ahas a ring-like shape about the rotational axis AX. The nozzle link plate34bis disposed more toward the bearing housing3than the drive ring34ain the axial direction. The drive ring34asurrounds a part of the nozzle ring32in the circumferential direction. The drive ring34ais rotatable relative to the nozzle ring32about the rotational axis AX. The nozzle link plate34bhas a bar-like shape. A first end of the nozzle link plate34bis connected to shaft end portions of the nozzle vanes33. A second end of the nozzle link plate34bis connected to the drive ring34a. The second end of the nozzle link plate34bmoves along the circumferential direction with the rotation of the drive ring34a. The plurality of nozzle vanes33connected to the first end of the nozzle link plate34brotates due to the movement of the second end of the nozzle link plate34b.

The turbocharger1further includes a spring member5. The spring member5is held by the variable geometry mechanism30and the bearing housing3. The spring member5is compressively deformed along the axial direction. The outer circumferential portion36of the nozzle ring32includes a first end face36athat contacts the spring member5. The distance in the axial direction between the first end face36aand an end face3aof the bearing housing3is smaller than the equilibrium length of the spring member5. The spring member5thus compressively deforms along the axial direction. The deformation of the spring member5is elastic deformation. The compressed spring member5thus exerts an elastic force.

In some examples, the spring member5is a disc spring. The disc spring has a disc shape having a through hole in the center, and is conically curved. The disc spring is used so as to compressively deform along a thickness direction. The end face3aof the bearing housing3contacts a bottom face of the spring member5. The end face3aof the bearing housing3contacts an outer diameter part of the disc spring. The first end face36aof the nozzle ring32contacts a top face of the spring member5. The first end face36aof the nozzle ring32contacts an inner diameter part of the disc spring. The first end face36aof the nozzle ring32is a plane extending in a radial direction intersecting the rotational axis AX. In the description below, the radial direction intersecting the rotational axis AX is referred to simply as the “radial direction.” The end face3aof the bearing housing3is also a plane extending in the radial direction. The first end face36aof the nozzle ring32is a ring-shaped surface extending in the circumferential direction. The end face3aof the bearing housing3is also a ring-shaped surface extending in the circumferential direction.

The spring member5may be a wave washer.

The nozzle ring32includes a second end face36b. The second end face36bis disposed on a back side of the first end face36a. The second end face36bcontacts an end face11aof the turbine housing11. The second end face36bis parallel to the first end face36a. The second end face36bhas a ring-like shape extending in the circumferential direction.

The turbine housing11contacts the second end face36bof the nozzle ring32. A region of the end face11aof the turbine housing11that contacts the second end face36bof the nozzle ring32has a ring-like shape extending in the circumferential direction. When viewed in the axial direction, the position in the radial direction at which the first end face36aof the nozzle ring32contacts the spring member5overlaps with the position in the radial direction of a surface at which the second end face36bof the nozzle ring32contacts the end face11aof the turbine housing11. In some examples, the elastic force exerted by the spring member5acts on the position at which the first end face36aof the nozzle ring32contacts the spring member5. When viewed in the axial direction, the position on which the elastic force acts overlaps with the surface at which the second end face36bof the nozzle ring32contacts the end face11aof the turbine housing11.

The outer circumferential portion36of the nozzle ring32includes a first outer circumferential face portion36cand a second outer circumferential face portion36d. The first outer circumferential face portion36c, which is a circumferential face, connects the first end face36ato the second end face36b. The second outer circumferential face portion36d, which is a circumferential face, extends toward the turbine housing11from the second end face36b. The first outer circumferential face portion36cand the second outer circumferential face portion36dare outer faces of cylinders about the rotational axis AX. The first outer circumferential face portion36cdefines an outer diameter of the variable geometry mechanism30in the radial direction. An outer diameter of the second outer circumferential face portion36dis smaller than an outer diameter of the first outer circumferential face portion36c. For example, the outer diameter of the second outer circumferential face portion36dmay be equal to an outer diameter of the CC plate31.

The turbine housing11has a first inner circumferential face portion11band a second inner circumferential face portion11c. The first inner circumferential face portion11bis an inner face of a cylinder about the rotational axis AX. The second inner circumferential face portion11cis also an inner face of a cylinder about the rotational axis AX. The first inner circumferential face portion11b, which is an inner circumferential face, extends toward the bearing housing3from the end face11aof the turbine housing11. The second inner circumferential face portion11c, which is an inner circumferential face, extends toward an opposite side of the first inner circumferential face portion11bfrom the end face11aof the turbine housing11. The end face11aof the turbine housing connects the first inner circumferential face portion11bto the second inner circumferential face portion11c. The first inner circumferential face portion11bfaces the rotational axis AX, and faces the first outer circumferential face portion36cof the nozzle ring32along the radial direction. The second inner circumferential face portion11cfaces the rotational axis AX, and faces the second outer circumferential face portion36dof the nozzle ring32along the radial direction.

An inner diameter of the first inner circumferential face portion11bof the turbine housing11is greater than the outer diameter of the first outer circumferential face portion36cof the nozzle ring32. There is a gap between the first inner circumferential face portion11band the first outer circumferential face portion36cin the radial direction. An inner diameter of the second inner circumferential face portion11cof the turbine housing11is greater than the outer diameter of the second outer circumferential face portion36dof the nozzle ring32. There is also a gap between the second inner circumferential face portion11cand the second outer circumferential face portion36din the radial direction.

The turbocharger1has a seal member37. The seal member37is disposed in the inner circumferential portion35. The seal member37has the shape of a ring-like plate member about the rotational axis AX. The seal member37may, for example, have a conically curved shape. The seal member37is disposed between the nozzle ring32and the bearing housing3. The seal member37is held by the nozzle ring32and the bearing housing3. The seal member37avoids exhaust gas on the turbine housing11side from flowing into the bearing housing3side.

The bearing housing3has a first abutting face3bfacing the axial direction such that the first abutting face3bis perpendicular to the axial direction. The first abutting face3bhas a ring-like shape extending in the circumferential direction. The position of the first abutting face3bis outward of the end face3aof the turbine housing11in the radial direction. The first abutting face3bprojects toward the turbine housing11from the end face3aof the bearing housing3in the axial direction. The turbine housing11has a second abutting face11d. The second abutting face11dabuts against the first abutting face3b. The second abutting face11dis parallel to the first abutting face3b. The second abutting face11dhas a ring-like shape extending in the circumferential direction. The second abutting face11dis an end face extending perpendicularly outward in the radial direction from the first inner circumferential face portion11b. The position at which the first abutting face3babuts against the second abutting face11dis outward of the spring member5in the radial direction.

In some examples, the turbocharger1, the spring member5presses the variable geometry mechanism30toward the turbine housing11. The variable geometry mechanism30has the nozzle ring32. The spring member5presses the first end face36aincluded in the outer circumferential portion36of the nozzle ring32. The force generated in the spring member5acts on the first end face36a. The second end face36bof the nozzle ring32is pressed against the turbine housing11. The second end face36bis disposed on the back side of the first end face36a. The reaction force of this force acts on the second end face36bdisposed on the back side of the first end face36a. The force of the spring member5and the reaction force may be coupled or interrelated. For example, the forces may have the same magnitude, but have opposite directions. Thus, the greater the distance between the force of the spring member5and the reaction force, the greater the force for bending a member. However, in the example turbocharger1, the distance from the position against which the spring member5is pressed to the position on which the reaction force of the pressing force acts is small. The variable geometry mechanism30can thus reduce the magnitude of the bending stress that is generated. The amount of deformation of the variable geometry mechanism30along the axial direction is reduced due to the reduction in the magnitude of the bending stress generated in the variable geometry mechanism30. Deformation of the variable geometry mechanism30at high temperatures due to the so-called creep phenomenon is also suppressed. The temperature of the components constituting the variable geometry mechanism30rises due to the high temperature gas supplied to the variable geometry mechanism30. The Young's modulus of the components constituting the variable geometry mechanism30decreases with the rise in the temperature. The components constituting the variable geometry mechanism30thus tend to deform. However, the deformation of the components constituting the variable geometry mechanism30is suppressed by the reduction in the bending stress generated in the variable geometry mechanism30.

In some examples, the deformation of the inner circumferential portion35curving toward the turbine housing11is suppressed. The distance between the CC plate31and the nozzle ring32can thus be maintained at a predetermined state. As a result, a state in which the nozzle vanes33can normally rotate can be maintained. A contact between the nozzle vanes33and the CC plate31is suppressed. Contact between the nozzle vanes33and the nozzle ring32is also suppressed. Normal rotary motion of the nozzle vanes33is thus maintained. The rotary motion of the nozzle vanes33influences the motion of the variable geometry mechanism30. The variable geometry mechanism30reliably moves by maintaining the rotary motion of the nozzle vanes33. Consequently, the reliability of the turbocharger1improves.

In some examples, the distance between the end face3aof the bearing housing3and the first end face36aof the nozzle ring32is determined on the basis of the position of the first abutting face3bin the axial direction. The compression of the spring member5is determined on the basis of the positions of the first abutting face3band the second abutting face11din the axial direction. As a result, the spring member5presses the variable geometry mechanism30. The deformation of the variable geometry mechanism30of the turbocharger1is thus suppressed.

When the temperature of the example turbocharger1rises, the variable geometry mechanism30can linearly expand in the radial direction, with the gap between the outer diameter of the first outer circumferential face portion36cand the inner diameter of the first inner circumferential face portion11bbeing the acceptable range. This deformation by expansion does not affect the motion of the variable geometry mechanism30. Deformation that interferes with the motion of the variable geometry mechanism30caused by the variable geometry mechanism30not being able to linearly expand in the radial direction can be suppressed. The reliability of the turbocharger1can thus be further improved.

In some examples, the variable geometry mechanism30is pressed against the turbine housing11by the spring member5. The pressing force of the spring member5in the axial direction is smaller than the axial force generated by the fastening of bolts and the like. Thus, linear expansion of the variable geometry mechanism30in the radial direction is facilitated.

A turbocharger1A illustrated inFIG.3is a variable geometry turbocharger. The turbocharger1A is different from the turbocharger1in that the turbocharger1A has an auxiliary spring member6and a heat shield38.

The turbocharger1A includes the auxiliary spring member6. The auxiliary spring member6is disposed between a variable geometry mechanism30A and the bearing housing3in the axial direction via the heat shield38.

The turbocharger1A includes the heat shield38instead of the seal member37. The heat shield38is disposed on an inner side of the inner circumferential portion35. The heat shield38has a ring-like shape about the rotational axis AX. The heat shield38inhibits heat transfer from the turbine housing11to the bearing housing3. As a result, the rise in the temperature of the components disposed on the bearing housing3side is suppressed. The auxiliary spring member6compressively deforms in the axial direction by being disposed between the heat shield38and the bearing housing3. The auxiliary spring member6exerts an elastic force opposing the compressive deformation. The auxiliary spring member6presses the heat shield38against the nozzle ring32.

In some examples, the force applied to the variable geometry mechanism30A can be distributed among the spring member5and the auxiliary spring member6. The deformation of the variable geometry mechanism30A of the turbocharger1A can be suppressed by distributing the force applied to the variable geometry mechanism30A. The heat shield38of the turbocharger1A is configured to press against the nozzle ring32.

A turbocharger1B illustrated inFIG.4is a variable geometry turbocharger. The turbocharger1B is different from the turbocharger1in the shape and the like of a bearing housing3B and a turbine housing11B.

The first abutting face3bof the bearing housing3B does not project from the end face3aof the bearing housing3B. The end face3aof the bearing housing3B is flush with the first abutting face3b. The position of the second abutting face11dof the turbine housing11B is adjusted along the axial direction such that the compression of the spring member5is smaller than that of the turbocharger1.

In some examples, the position of the first abutting face3band the position of the end face3athat holds the spring member5are defined to be on the sample plane. The compression of the spring member5of the turbocharger1B can thus be managed. The reliability of the turbocharger1B can be improved similarly to the turbocharger1.

Another example turbocharger1C is illustrated inFIG.5. The turbocharger1C is different from the turbocharger1in the shape and the like of a bearing housing3C and a variable geometry mechanism30C.

The bearing housing3C has a third inner circumferential face3cfacing the radial direction. The third inner circumferential face3cis an inner face of a cylinder about the rotational axis AX. In the bearing housing3C, the third inner circumferential face3cextends perpendicularly toward a turbine housing11C from the end face3aof the bearing housing3C that holds the spring member5. The third inner circumferential face3cfaces inward in the radial direction and contacts the spring member5.

A nozzle ring32C has a third outer circumferential face36ethat faces outward in the radial direction. The third outer circumferential face36eis an outer face of a cylinder about the rotational axis AX. In the nozzle ring32C, the third outer circumferential face36eextends perpendicularly toward the bearing housing3C from the first end face36athat holds the spring member5. An outer diameter of the third outer circumferential face36eis smaller than the outer diameter of the first outer circumferential face portion36c. The third outer circumferential face36efaces outward in the radial direction and contacts the spring member5.

The spring member5of the turbocharger1C is disposed between the first end face36aof the nozzle ring32C and the end face3aof the bearing housing3C in the axial direction. The spring member5is held by the nozzle ring32C and the bearing housing3C. Additionally, the spring member5is disposed between the third outer circumferential face36eof the nozzle ring32C and the third inner circumferential face3cof the bearing housing3C in the radial direction. The spring member5is held by the nozzle ring32C and the bearing housing3C. Accordingly, reliability can be improved similarly to the turbocharger1.

It is to be understood that not all aspects, advantages and features described herein may necessarily be achieved by, or included in, any one particular example. Indeed, having described and illustrated various examples herein, it may be apparent that other examples may be modified in arrangement and detail. For example, the above configuration described with respect to the example turbocharger1C may also be applied to other turbocharges disclosed herein, including the turbocharger1A and the turbocharger1B.