JP2019157912A - Supercharger - Google Patents

Abstract

To provide a supercharger capable of suppressing inclination during the rotation of a rotary shaft for a long time, and capable of preventing the rotary shaft and a thrust member from coming into contact with a thrust bearing.SOLUTION: A supercharger includes: a rotary shaft; a compressor wheel provided at one end of the rotary shaft; a thrust member fitted in the rotary shaft; a thrust bearing arranged by being adjacent to the thrust member in an axial direction of the rotary shaft, and for supporting the rotary shaft in a thrust direction; and a housing for storing the thrust member and the thrust bearing. A clearance is formed between an outer peripheral surface of the thrust member and the housing in a direction orthogonal to the axial direction, and the clearance is so constituted that an oil flows into it. When the rotary shaft and the thrust member rotate, the oil which has flowed into the clearance generates an oil film pressure for pressing the thrust member along the direction orthogonal to the axial direction.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a supercharger including a thrust bearing that supports a rotating shaft in a thrust direction.

  2. Description of the Related Art A turbocharger that includes a rotating shaft, a thrust collar attached to the outer periphery of the rotating shaft, and a thrust bearing that supports a thrust load that acts on the rotating shaft via the thrust collar is widely known (for example, Patent Document 1).

  In recent years, with the demand for engine downsizing, there has been a demand for an increase in capacity of a supercharger attached to the engine. When the supercharger has a large capacity, the thrust load acting on the rotating shaft of the supercharger increases, so that the inclination of the shaft center during rotation of the rotating shaft increases. When the inclination of the axis of the rotating shaft is increased, one-side contact occurs between the thrust collar and the thrust bearing, and there is a high possibility that the thrust bearing and the thrust collar are suddenly heated and seized.

  The turbocharger described in Patent Document 1 is provided with an elastically deformable inner peripheral pad on the thrust collar side end face of the thrust bearing, and the inner peripheral pad is separated from the thrust bearing when the rotating shaft and the thrust collar are inclined. As described above, it is described that an oil film thickness for supporting a thrust load is secured between the inner circumferential pad and the thrust collar by elastically deforming the inner circumferential pad so that the inner circumferential pad exhibits a thrust load bearing ability. .

JP 2003-232340 A

  In the turbocharger described in Patent Document 1, there is a possibility that the inner peripheral pad of the thrust bearing may be fatigued due to the repeated deformation and restoration in the elastic deformation described above. In addition, due to a decrease in elastic force due to fatigue of the inner peripheral pad, it is not possible to secure the oil film thickness between the thrust bearing and the thrust collar, causing a sudden temperature rise or seizure in the thrust bearing or thrust collar. There is a fear.

  In view of the circumstances described above, the object of at least one embodiment of the present invention is to prevent tilting of the rotating shaft during rotation over a long period of time and to prevent the rotating shaft and the thrust member from contacting the thrust bearing. It is to provide a supercharger that can do.

(1) A turbocharger according to at least one embodiment of the present invention is:
A rotation axis;
A compressor wheel provided at one end of the rotating shaft;
A thrust member fitted to the rotating shaft;
A thrust bearing disposed adjacent to the thrust member in the axial direction of the rotating shaft and supporting the rotating shaft in the thrust direction;
A housing that houses the thrust member and the thrust bearing,
A clearance is formed between the outer peripheral surface of the thrust member and the housing in a direction orthogonal to the axial direction in at least part of the axial direction and the circumferential direction of the rotating shaft, and oil flows into the clearance. Configured,
When the rotating shaft and the thrust member rotate, the oil that has flowed into the clearance generates an oil film pressure that presses the thrust member along a direction orthogonal to the axial direction.

  According to the configuration of (1) above, the supercharger is connected to the rotating shaft, the compressor wheel provided at one end of the rotating shaft, the thrust member fitted to the rotating shaft, and the thrust member in the axial direction of the rotating shaft. A thrust bearing that is disposed adjacently and supports the rotating shaft in the thrust direction, and a housing that houses the thrust member and the thrust bearing are provided. A clearance is formed between the outer peripheral surface of the thrust member and the housing in a direction perpendicular to the axial direction of the rotating shaft, and at least part of the axial direction and the circumferential direction of the rotating shaft, and oil is allowed to flow into the clearance. ing. And when a rotating shaft and a thrust member rotate, it is comprised so that the oil which flowed into clearance may generate the oil film pressure which presses a thrust member along the direction orthogonal to an axial direction.

  For this reason, the oil flowing into the clearance forms a lubricating film when the rotating shaft and the thrust member rotate, and generates an oil film pressure that presses the thrust member toward the axis along a direction orthogonal to the axial direction. In addition, it is possible to suppress the inclination of the axis line when the rotating shaft rotates. Therefore, it is possible to prevent the rotating shaft and the thrust member from coming into contact with the thrust bearing. By preventing contact between the rotating shaft or thrust member and the thrust bearing, damage due to wear of the rotating shaft, thrust member and thrust bearing can be suppressed, and the turbocharger can be used for a long period of time. .

(2) In some embodiments, in the configuration of (1) above,
When the clearance size is C and the outer dimension of the thrust member is D, at least a part of the clearance satisfies the condition that the clearance ratio C / D is 5/1000 ≦ C / D ≦ 10/1000. .

  According to the configuration of (2) above, at least a part of the clearance satisfies the above-described conditions, so that the oil flowing into the clearance can exert an appropriate oil film pressure. When the clearance ratio is C / D <5/1000, there is a possibility that the rotating shaft or the thrust member may come into contact with the thrust bearing due to the inclination of the rotating shaft during rotation. Further, when the clearance ratio is 10/1000 <C / D, there is a possibility that the oil cannot exhibit a sufficient oil film pressure.

(3) In some embodiments, in the above configuration (1) or (2),
The clearance is formed such that at least a part of the axial bearing side on the thrust bearing side is larger than a side away from the thrust bearing.

  According to the configuration of the above (3), the oil can easily flow from the clearance thrust bearing side, and the oil is difficult to flow from the clearance side of the thrust bearing. For this reason, the oil film pressure which presses the thrust member by oil along the direction orthogonal to an axial direction can be increased.

(4) In some embodiments, in the configuration of (3) above,
The inner dimension of the portion forming the clearance of the housing is formed to be larger than at least a part of the axial bearing side on the thrust bearing side away from the thrust bearing.

  According to the configuration (4), the oil can easily flow from the clearance thrust bearing side, and the oil is difficult to flow from the clearance side of the thrust bearing. For this reason, the oil film pressure which presses the thrust member by oil along the direction orthogonal to an axial direction can be increased.

(5) In some embodiments, in the above configuration (3) or (4),
The outer dimension of the thrust member is formed so that at least a part of the thrust bearing side in the axial direction is smaller than the side away from the thrust bearing.

  According to the configuration of (5), the oil can easily flow from the thrust bearing side of the clearance, and the oil is difficult to flow from the clearance side of the thrust bearing. For this reason, the oil film pressure which presses the thrust member by oil along the direction orthogonal to an axial direction can be increased.

(6) In some embodiments, in the configuration of (3) above,
The thrust member has a chamfered surface at least at a part of an end portion on the thrust bearing side in the axial direction.

  According to the configuration of (6), since the chamfered surface is provided on at least a part of the end portion on the thrust bearing side in the axial direction of the thrust member, oil can easily flow from the thrust bearing side of the clearance. And it is difficult for oil to flow out from the side of the clearance away from the thrust bearing. For this reason, the oil film pressure which presses the thrust member by oil along the direction orthogonal to an axial direction can be increased. Further, the chamfered surface can be easily formed by cutting or the like.

(7) In some embodiments, in the above configurations (1) to (6),
The housing is configured such that enlarged diameter portions where the clearance is partially enlarged in the circumferential direction of the rotating shaft are evenly arranged.

  According to the configuration of (7), the oil easily flows into the enlarged diameter portion of the clearance by providing the enlarged diameter portion where the clearance is partially enlarged by the housing and the portion where the clearance is smaller than the enlarged diameter portion. In addition, it is difficult for the oil to flow out from a portion where the clearance is smaller than the diameter-enlarged portion of the clearance. For this reason, since the peak part of an oil film pressure can be formed in several places in the circumferential direction, the oil film pressure which presses the thrust member by oil along the direction orthogonal to an axial direction can be increased.

  In particular, when at least a part of the clearance on the thrust bearing side in the axial direction is formed larger than the clearance on the side away from the thrust bearing, at the peak portion of the oil film pressure formed at a plurality of locations in the circumferential direction. The oil film pressure can be increased.

(8) In some embodiments, in the configurations of (1) to (7) above,
The housing is provided with a non-contact seal including a plurality of recesses on a surface facing the back surface of the compressor wheel.
According to the configuration of (8) above, the rotating shaft and the compressor wheel are rotated by the non-contact seal including a plurality of recesses so that the compressed gas flowing between the back surface of the compressor wheel and the surface of the housing facing the back surface rotates. In this case, a lubricating film is formed and a gas film pressure that presses the compressor wheel along the axial direction is generated, so that the inclination of the axis during rotation of the rotating shaft can be suppressed. Therefore, it is possible to prevent the compressor wheel from contacting the housing. By preventing contact between the compressor wheel and the housing, damage due to wear of the compressor wheel and the housing can be suppressed, and the supercharger can be used for a long period of time.

(9) In some embodiments, in the above configurations (1) to (8),
A turbine wheel provided at the other end of the rotating shaft is further provided.
According to the configuration of (9) above, the supercharger is a turbocharger including a compressor wheel and a turbine wheel. In the turbocharger, the pressure of a gas such as compressed air that acts on the compressor wheel is lower than the pressure of a gas such as exhaust gas that acts on the turbine wheel. Will be greatly touched. Even with such a rotary shaft of the turbocharger, the oil flowing into the clearance as described above causes the oil film pressure to act on the thrust member, so that the inclination of the rotary shaft during rotation can be suppressed.

  According to at least one embodiment of the present invention, there is provided a supercharger capable of suppressing the inclination of the rotating shaft during rotation and preventing the rotating shaft and the thrust member from contacting the thrust bearing. The

It is the schematic for demonstrating the whole structure of the supercharger concerning one Embodiment of this invention. It is a schematic sectional drawing which expands and shows a part of supercharger shown in FIG. It is a schematic sectional drawing in alignment with the axial direction of the rotating shaft which shows schematically the main components inside the housing in the supercharger concerning one embodiment of the present invention. It is a graph which shows roughly the relation between the clearance ratio and oil film pressure in the supercharger concerning one embodiment of the present invention. It is a schematic sectional drawing in alignment with the axial direction of the rotating shaft which shows schematically the main components inside the housing in the supercharger concerning other one embodiment of the present invention. It is a schematic sectional drawing in alignment with the axial direction of the rotating shaft which shows schematically the main components inside the housing in the supercharger concerning other one embodiment of the present invention. It is a schematic sectional drawing in alignment with the axial direction of the rotating shaft which shows schematically the main components inside the housing in the supercharger concerning other one embodiment of the present invention. It is a schematic sectional drawing along the circumferential direction of the rotating shaft which shows roughly the main components inside the housing in the supercharger concerning other one embodiment of the present invention. It is a schematic sectional drawing along the circumferential direction of the rotating shaft which shows roughly the main components inside the housing in the supercharger concerning other one embodiment of the present invention. It is a schematic sectional drawing in alignment with the axial direction of the rotating shaft which shows schematically the main components inside the housing in the supercharger concerning other one embodiment of the present invention. It is a figure for demonstrating the supercharger concerning other one Embodiment of this invention, Comprising: It is a schematic sectional drawing along the axial direction of the rotating shaft which shows a compressor wheel and a housing schematically.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.
For example, expressions expressing relative or absolute arrangements such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial” are strictly In addition to such an arrangement, it is also possible to represent a state of relative displacement with an angle or a distance such that tolerance or the same function can be obtained.
For example, an expression indicating that things such as “identical”, “equal”, and “homogeneous” are in an equal state not only represents an exactly equal state, but also has a tolerance or a difference that can provide the same function. It also represents the existing state.
For example, expressions representing shapes such as quadrangular shapes and cylindrical shapes represent not only geometrically strict shapes such as quadrangular shapes and cylindrical shapes, but also irregularities and chamfers as long as the same effects can be obtained. A shape including a part or the like is also expressed.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one constituent element are not exclusive expressions for excluding the existence of the other constituent elements.
In addition, about the same structure, the same code | symbol may be attached | subjected and description may be abbreviate | omitted.

  FIG. 1 is a schematic diagram for explaining the overall structure of a supercharger according to an embodiment of the present invention. FIG. 2 is a schematic sectional view showing a part of the turbocharger shown in FIG. 1 in an enlarged manner. FIG. 3 is a schematic cross-sectional view along the axial direction of the rotating shaft schematically showing main components inside the housing in the supercharger according to the embodiment of the present invention.

  A supercharger 1 according to some embodiments shown in FIGS. 1 to 11 is a turbocharger for a ship, and as shown in FIGS. 1 and 2, in the axial direction (left and right direction in FIGS. 1 and 2). A rotating shaft 2 extending along the axis, a compressor wheel 11 provided at one end of the rotating shaft 2 in the axial direction, and a turbine wheel 12 provided at the other end in the axial direction of the rotating shaft 2 are provided. 2 and 3, the supercharger 1 is disposed adjacent to the thrust member 3 in the axial direction of the rotating shaft 2 and the thrust member 3 (thrust collar) fitted to the rotating shaft 2. In addition, a thrust bearing 4 that supports the rotating shaft 2 in the thrust direction, and a housing 5 that houses the thrust member 3 and the thrust bearing 4 are further provided.

  As shown in FIG. 2, the turbocharger housing 5 includes a compressor housing 5 </ b> A that houses the compressor wheel 11, a turbine housing 5 </ b> B that houses the turbine wheel 12, and a bearing housing 5 </ b> C that houses the thrust bearing 4, Is included. As shown in FIG. 2, the bearing housing 5C is disposed between the compressor housing 5A and the turbine housing 5B in the axial direction of the rotary shaft 2, and the compressor housing 5A and the turbine are screwed using, for example, bolts. It is fixed to the housing 5B. As shown in FIG. 2, the bearing housing 5 </ b> C houses the thrust member 3 and the thrust bearing 4 inside the radial direction of the rotating shaft 2 (direction orthogonal to the axial direction of the rotating shaft 2).

  Further, as shown in FIG. 2, the supercharger 1 further includes a thrust bearing 13 on the opposite side of the thrust bearing 4 with respect to the thrust member 3 in the axial direction of the rotating shaft 2. Similar to the thrust bearing 4, the thrust bearing 13 is disposed adjacent to the thrust member 3 in the axial direction of the rotating shaft 2 and supports the rotating shaft 2 in the thrust direction.

  Further, as shown in FIG. 2, the supercharger 1 further includes a pair of journal bearings 14 and 15 that are housed inside the bearing housing 5 </ b> C in the radial direction and that rotatably support the rotary shaft 2. . As shown in FIG. 2, the journal bearing 14 is disposed on the compressor wheel 11 side in the axial direction of the rotating shaft 2, and the journal bearing 15 is disposed on the turbine wheel 12 side in the axial direction of the rotating shaft 2. Yes.

  As shown in FIG. 3, the thrust member 3 has an outer peripheral surface 31 and an inner peripheral surface 32, and is fixed to the rotary shaft 2 by fitting the inner peripheral surface 32 to the outer peripheral surface 21 of the rotary shaft 2. ing. For this reason, the thrust member 3 rotates in synchronization with the rotation of the rotating shaft 2. As shown in FIG. 3, the thrust member 3 includes a thrust member 3 </ b> A formed in a circular tube having a constant outer diameter.

  As shown in FIG. 3, the thrust bearing 4 is formed in a circular shape having an outer peripheral surface 41 and an inner peripheral surface 42, and the outer peripheral surface 41 is fitted to the housing 5 and fixed to the housing 5. The rotary shaft 2 is loosely inserted through the inner peripheral surface 42.

  As shown in FIG. 3, the housing 5 includes a thrust member storage portion 51 for storing the thrust member 3 inside the radial direction of the rotary shaft 2, and a thrust bearing fitting portion 52 for fitting the thrust bearing 4. At least. A clearance 6 is formed between the outer peripheral surface 41 of the thrust member 3 and the housing 5 in the radial direction of the rotating shaft 2 in at least part of the axial direction and the circumferential direction of the rotating shaft 2.

  The oil flows into the clearance 6 and the oil flowing into the clearance 6 moves along the direction orthogonal to the axial direction of the thrust member 3 when the rotating shaft 2 and the thrust member 3 rotate. An oil film pressure to be pressed is generated. Specifically, as shown in FIG. 3, oil is supplied between the inner peripheral surface 42 of the thrust bearing 4 and the outer peripheral surface 21 of the rotary shaft 2. The oil supplied between the inner peripheral surface 42 of the thrust bearing 4 and the outer peripheral surface 21 of the rotating shaft 2 faces the end surface 43 on the thrust member 3 side in the axial direction of the thrust bearing 4 and the end surface 43 of the thrust member 3. And the first end face 33 that flows into the clearance 6. As shown in FIG. 3, the oil flowing into the clearance 6 generates an oil film pressure that presses the thrust member 3 along the radial direction when the rotating shaft 2 and the thrust member 3 rotate.

  As described above, the supercharger 1 according to some embodiments includes the above-described rotating shaft 2, the above-described compressor wheel 11 provided at one end of the rotating shaft 2, and the above-described rotating shaft 2. The thrust member 3 is disposed adjacent to the thrust member 3 in the axial direction of the rotating shaft 2 and accommodates the above-described thrust bearing 4 that supports the rotating shaft 2 in the thrust direction, and the thrust member 3 and the thrust bearing 4. The housing 5 described above is provided. A clearance 6 is formed between the outer peripheral surface 31 of the thrust member 3 and the housing 5 in a direction orthogonal to the axial direction of the rotary shaft 2, and oil is configured to flow into the clearance 6. Furthermore, when the rotating shaft 2 and the thrust member 3 rotate, the oil flowing into the clearance 6 generates an oil film pressure that presses the thrust member 3 along a direction orthogonal to the axial direction.

  For this reason, as shown in FIG. 3, the oil flowing into the clearance 6 forms a lubricating film when the rotating shaft 2 and the thrust member 3 rotate, and moves the thrust member 3 along the direction orthogonal to the axial direction. Since the oil film pressure that presses toward the axis is generated, the inclination of the axis during rotation of the rotary shaft 2 can be suppressed. Therefore, it is possible to prevent the rotating shaft 2 and the thrust member 3 from coming into contact with the thrust bearing 4. By preventing contact between the rotating shaft 2, the thrust member 3, and the thrust bearing 4, damage due to wear of the rotating shaft 2, the thrust member 3, and the thrust bearing 4 can be suppressed. It becomes possible to use.

  In some embodiments, as shown in FIG. 3, when the size of the clearance 6 is C and the outside dimension of the thrust member 3 is D, the axial direction and the circumferential direction of the rotary shaft 2 At least a portion of the clearance 6 satisfies the condition that the clearance ratio C / D is 5/1000 ≦ C / D ≦ 10/1000. Here, FIG. 4 is a graph schematically showing the relationship between the clearance ratio and the oil film pressure in the supercharger according to the embodiment of the present invention. As shown in FIG. 4, when the clearance ratio C / D decreases, the oil film pressure exerted by the oil in the clearance 6 tends to increase. However, if the clearance ratio C / D is too small, the possibility that the rotating shaft 2 or the thrust member 3 contacts the thrust bearing 4 or seizure increases. Therefore, when the clearance ratio C / D satisfies the above-described conditions, the oil flowing into the clearance 6 can exhibit an appropriate oil film pressure. When the clearance ratio is C / D <5/1000, the rotation shaft 2 or the thrust member 3 may come into contact with the thrust bearing 4 due to the inclination of the rotation shaft 2 during rotation. Further, when the clearance ratio is 10/1000 <C / D, as shown in FIG. 4, there is a possibility that the oil cannot exert a sufficient oil film pressure.

  FIGS. 5-7 is a schematic sectional drawing along the axial direction of the rotating shaft which shows schematically the main components inside the housing in the supercharger concerning other one Embodiment of this invention. As shown in FIGS. 5 to 7, in some embodiments, the above-described clearance 6 is formed to be larger than at least a part on the thrust bearing 4 side in the axial direction on the side away from the thrust bearing 4. . In this case, the oil can easily flow from the thrust bearing 4 side of the clearance 6 and the oil is difficult to flow from the side of the clearance 6 away from the thrust bearing 4. For this reason, the oil film pressure which presses the thrust member 3 with oil along the direction orthogonal to the axial direction can be increased.

  In the embodiment shown in FIG. 5, the inner dimension of the portion that forms the clearance 6 of the housing 5 described above is formed to be larger than at least a part on the thrust bearing 4 side in the axial direction compared to the side away from the thrust bearing 4. ing. Here, the part forming the clearance 6 of the housing 5 means the clearance forming part 54 including the inner side surface 53 facing the outer peripheral surface 31 of the thrust member 3. Specifically, as shown in FIG. 5, the clearance forming portion 54 is formed with a tapered surface 55 that gradually decreases in thickness in the axial direction toward the thrust bearing 4 side in the axial direction. . For this reason, the inner dimension of the clearance forming portion 54 is formed larger on the thrust bearing 4 side in the axial direction than on the side away from the thrust bearing 4. In this case, the oil can easily flow from the thrust bearing 4 side of the clearance 6 and the oil is difficult to flow from the side of the clearance 6 away from the thrust bearing 4. For this reason, the oil film pressure which presses the thrust member 3 with oil along the direction orthogonal to the axial direction can be increased.

  In the embodiment shown in FIG. 6, the above-described outer dimension of the thrust member 3 is formed to be smaller than at least a part of the thrust bearing 4 side in the axial direction on the side away from the thrust bearing 4. Specifically, the thrust member 3 includes a thrust member 3B formed in a truncated cone shape as shown in FIG. The thrust member 3B is formed such that the outer diameter dimension of the first end face 33 described above is smaller than the outer diameter dimension of the second end face 34 opposite to the first end face 33 in the axial direction. That is, as shown in FIG. 6, the thrust member 3B is formed with a tapered surface 35 whose outer diameter dimension gradually decreases toward the thrust bearing 4 side in the axial direction. In this case, the oil can easily flow from the thrust bearing 4 side of the clearance 6 and the oil is difficult to flow from the side of the clearance 6 away from the thrust bearing 4. For this reason, the oil film pressure which presses the thrust member 3B by oil along the direction orthogonal to an axial direction can be increased. Further, the thrust member 3 </ b> B is easier to change and process than the housing 5.

  In the embodiment shown in FIG. 7, the thrust member 3 described above includes a thrust member 3 </ b> C having a chamfered surface 36 at at least a part of an end portion on the thrust bearing 4 side in the axial direction of the rotating shaft 2. As shown in FIG. 7, the thrust member 3 </ b> C is formed in a circular tube shape, and a chamfered surface 36 is formed at the outer peripheral end portion of the first end surface 33. In the embodiment shown in FIG. 7, the chamfered surface 36 is subjected to R chamfering in which an outer contour is formed in an arc shape in a cross-sectional view along the axial direction of the rotating shaft 2. C chamfering in which the outer contour is formed in a straight line shape in a cross-sectional view along the line may be performed. In this case, since the chamfered surface 36 is provided on at least a part of the end of the thrust member 3C on the thrust bearing 4 side in the axial direction, the oil can easily flow from the thrust bearing 4 side of the clearance 6. In addition, it is difficult for the oil to flow from the side of the clearance 6 away from the thrust bearing 4. For this reason, the oil film pressure which presses the thrust member 3C by oil along the direction orthogonal to the axial direction can be increased. The chamfered surface 36 can be easily formed by cutting or the like.

  8 and 9 are schematic cross-sectional views along the circumferential direction of the rotating shaft schematically showing main components inside the housing in the turbocharger according to another embodiment of the present invention. As shown in FIGS. 8 and 9, in some embodiments, the above-described housing 5 is evenly arranged with the enlarged diameter portions 62 in which the clearance 6 is partially enlarged in the circumferential direction of the above-described rotating shaft 2. It is comprised so that. Here, that the diameter-expanded portions 62 are evenly arranged means that the resultant force of the oil film pressure generated in the clearance 6 when the rotating shaft 2 rotates does not act as an eccentric load that eccentrically rotates the rotating shaft 2. I mean.

  Specifically, in the embodiment shown in FIG. 8, the inner surface 53 of the housing 5 has 180 concave portions 56 that are recessed so that the contour shape in a sectional view becomes an arc shape toward the radially outer side of the rotating shaft 2. By being provided at every angle, the contour shape in sectional view is formed in an elliptical shape. The clearance 6 formed between the inner surface 53 of the housing 5 and the outer peripheral surface 31 of the thrust member 3 is larger than the two small diameter portions 61 and the small diameter portion 61 in the circumferential direction of the rotary shaft 2. The two enlarged diameter portions 62 are alternately provided. The circles indicated by dotted lines in FIGS. 8 and 9 are provided for convenience of explanation, and the size of the clearance 6 is the same as that of the small diameter portion 61.

  In the embodiment shown in FIG. 9, the inner surface 53 of the housing 5 has a recessed portion 56 that is recessed so that the contour shape in a cross-sectional view becomes an arc shape toward the radially outer side of the rotating shaft 2 every 120 °. By being provided, the outline shape in the cross-sectional view is formed in a triangular shape with rounded corners. The clearance 6 formed between the inner surface 53 of the housing 5 and the outer peripheral surface 31 of the thrust member 3 is larger in the circumferential direction of the rotating shaft 2 than the three small diameter portions 61 and the small diameter portion 61. The two enlarged diameter portions 62 are alternately provided.

  According to the above configuration, by providing the enlarged diameter portion 62 in which the clearance 6 is partially enlarged by the housing 5 and the portion (small diameter portion 61) having a smaller clearance than the enlarged diameter portion 62, the oil is in the clearance 6. The oil can easily flow into the enlarged diameter portion 62, and the oil is difficult to flow out from the portion (small diameter portion 61) where the clearance is smaller than the enlarged diameter portion 62 of the clearance 6. For this reason, since the peak part of an oil film pressure can be formed in several places in the circumferential direction, the oil film pressure which presses the thrust member 3 by oil along the direction orthogonal to the axial direction of the rotating shaft 2 can be increased. In particular, when at least a part of the clearance 6 on the thrust bearing 4 side in the axial direction of the rotary shaft 2 is formed larger than the clearance 6 on the side away from the thrust bearing 4, it is formed at a plurality of locations in the circumferential direction. It is possible to increase the oil film pressure at the peak portion of the formed oil film pressure.

  FIG. 10 is a schematic cross-sectional view along the axial direction of the rotation shaft schematically showing main components inside the housing in the supercharger according to another embodiment of the present invention. Some embodiments mentioned above are applicable also to the supercharger 1 provided with the floating disk 7 as shown in FIG. That is, in some embodiments, the supercharger 1 described above is a floating disk 7 that is loosely inserted into the rotary shaft 2 described above, as shown in FIG. 10, and the axial direction of the rotary shaft 2 described above. The floating disk 7 is further provided between the thrust member 3 and the thrust bearing 4. In other words, the thrust bearing 4 is disposed adjacent to the thrust member 3 via the floating disk 7. As shown in FIG. 10, the floating disk 7 is formed in a circular tube shape having an outer peripheral surface 71 and an inner peripheral surface 72, and a gap through which oil flows between the outer peripheral surface 71 and the inner side surface 53 of the housing 5. Is provided, and the rotating shaft 2 is loosely inserted through the inner peripheral surface 72. Even in the supercharger 1 having such a floating disk 7, the oil flows into the clearance 6, so that the oil flowing into the clearance 6 can apply an oil film pressure to the thrust member 3.

  FIG. 11 is a diagram for explaining a supercharger according to another embodiment of the present invention, and is a schematic cross-sectional view along the axial direction of a rotating shaft schematically showing a compressor wheel and a housing. As shown in FIG. 11, in some embodiments, the housing 5 described above is provided with a non-contact seal 8 including a plurality of recesses 81 on a surface 57 facing the back surface 111 of the compressor wheel 11 described above. . The plurality of recesses 81 are arranged side by side along the circumferential direction and the radial direction of the rotating shaft 2, and are formed to be hemispherically recessed from the surface 57 along the axial direction of the rotating shaft 2.

  According to said structure, the compressed gas which flowed between the back surface 111 of the compressor wheel 11 and the surface 57 facing the back surface 111 of the housing 5 by the non-contact seal 8 containing the some recessed part 81 is the rotating shaft 2 and Since the lubricating film is formed when the compressor wheel 11 rotates and the gas film pressure that presses the compressor wheel 11 along the axial direction is generated, the inclination of the axis during rotation of the rotary shaft 2 can be suppressed. Therefore, it is possible to prevent the compressor wheel 11 from contacting the housing 5. By preventing contact between the compressor wheel 11 and the housing 5, damage due to wear of the compressor wheel 11 and the housing 5 can be suppressed, and the supercharger 1 can be used for a long period of time. In addition, this structure shown by FIG. 11 may be used independently for a supercharger, and may be used with some embodiment mentioned above.

  As described above, in some embodiments, the above-described supercharger 1 further includes a turbine wheel 12 provided at the other end in the axial direction of the rotating shaft 2 as illustrated in FIGS. . That is, the supercharger 1 described above is a turbocharger including a compressor wheel 11 and a turbine wheel 12. In this case, the pressure of the gas such as compressed air that acts on the compressor wheel 11 is lower than the pressure of the gas such as exhaust gas that acts on the turbine wheel 12. Compared with the turbine wheel 12 side, it will be greatly touched. Even in the rotating shaft 2 of such a turbocharger, the oil flowing into the clearance 6 as described above applies the oil film pressure to the thrust member 3, thereby suppressing the inclination of the rotating shaft 2 during rotation. be able to.

  In the above-described embodiments, the turbocharger 1 is described as an example of the turbocharger for the supercharger 1. However, the supercharger 1 is not limited to the marine turbocharger, and various modifications can be made. Is possible. For example, the supercharger 1 may be a turbocharger for automobiles, or may be a device other than a turbocharger. Further, the supercharger 1 may be configured not to include the turbine wheel 12 described above. Examples of the supercharger 1 that does not include the turbine wheel 12 include an electric compressor that rotates the compressor wheel 11 with an electric motor (not shown).

  In some embodiments described above, the thrust member 3 is formed in a circular tubular shape or a truncated cone shape, but may be formed in a rectangular tubular shape or a truncated pyramid shape. In some embodiments described above, the inner surface 53 of the housing 5 is configured to continuously cover the entire circumference of the outer peripheral surface 31 of the thrust member 3. You may make it cover a part in direction intermittently.

  The present invention is not limited to the above-described embodiments, and includes forms obtained by modifying the above-described embodiments and forms obtained by appropriately combining these forms.

DESCRIPTION OF SYMBOLS 1 Supercharger 11 Compressor wheel 111 Back surface 12 Turbine wheel 13 Thrust bearing 14, 15 Journal bearing 2 Rotating shaft 21 Outer surface 3, 3A-3C Thrust member 31 Outer surface 32 Inner surface 33 First end surface 34 Second end surface 35 Taper Surface 36 Chamfered surface 4 Thrust bearing 41 Outer peripheral surface 42 Inner peripheral surface 43 End surface 5 Housing 5A Compressor housing 5B Turbine housing 5C Bearing housing 51 Thrust member accommodating portion 52 Thrust bearing fitting portion 53 Inner side surface 54 Clearance forming portion 55 Tapered surface 56 Recessed portion 57 Surface 6 Clearance 61 Small diameter portion 62 Large diameter portion 7 Floating disk 71 Outer surface 72 Inner surface 8 Non-contact seal 81 Recess

Claims (9)

A rotation axis;
A compressor wheel provided at one end of the rotating shaft;
A thrust member fitted to the rotating shaft;
A thrust bearing disposed adjacent to the thrust member in the axial direction of the rotating shaft and supporting the rotating shaft in the thrust direction;
A housing that houses the thrust member and the thrust bearing,
A clearance is formed between the outer peripheral surface of the thrust member and the housing in a direction orthogonal to the axial direction in at least part of the axial direction and the circumferential direction of the rotating shaft, and oil flows into the clearance. Configured,
When the rotating shaft and the thrust member rotate, the oil that has flowed into the clearance generates an oil film pressure that presses the thrust member along a direction orthogonal to the axial direction. Feeder. When the clearance size is C and the outer dimension of the thrust member is D, at least a part of the clearance satisfies the condition that the clearance ratio C / D is 5/1000 ≦ C / D ≦ 10/1000. The supercharger according to claim 1. 3. The turbocharger according to claim 1, wherein at least a part of the clearance in the axial direction on the thrust bearing side is formed to be larger than the clearance away from the thrust bearing. 4. The supercharging according to claim 3, wherein an inner dimension of a portion of the housing forming the clearance is formed to be larger than at least a part on the thrust bearing side in the axial direction compared to a side away from the thrust bearing. Machine. 5. The supercharger according to claim 3, wherein an outer dimension of the thrust member is formed to be smaller than at least a part of the thrust bearing side in the axial direction on a side away from the thrust bearing. The supercharger according to claim 3, wherein the thrust member has a chamfered surface at least at a part of an end portion on the thrust bearing side in the axial direction. The supercharging according to any one of claims 1 to 6, wherein the housing is configured such that a diameter-expanded portion in which the clearance is partially enlarged in a circumferential direction of the rotation shaft is evenly arranged. Machine. The supercharger according to any one of claims 1 to 7, wherein the housing is provided with a non-contact seal including a plurality of recesses on a surface facing the back surface of the compressor wheel. The supercharger according to any one of claims 1 to 8, further comprising a turbine wheel provided at the other end of the rotating shaft.

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