JP4440819B2 - Exhaust gas seal structure of turbocharger - Google Patents

Description

  The present invention relates to an exhaust gas seal structure for a turbocharger that allows exhaust gas to flow into a turbine housing and makes the turbine capacity variable.

  The turbocharger supplies compressed air to the engine using the energy of the exhaust gas flowing into the turbine housing. Specifically, the turbine rotor provided inside the turbine housing is rotated by the exhaust gas from the engine, and the compressor rotor in the compressor housing connected coaxially with the turbine rotor is rotated and sucked into the compressor housing. The compressed air is compressed and supplied to the engine.

  A turbocharger usually has a valve member that controls the flow of exhaust gas flowing into the turbine housing in order to efficiently use the energy of exhaust gas that fluctuates according to the rotational speed that changes from the low speed range to the high speed range of the engine. Is provided. Such valve members include a wastegate valve that controls the amount of exhaust gas sent to the turbine rotor so that the supercharging pressure does not become too high, and the turbine capacity is switched according to the amount of exhaust gas flowing into the valve rotor. There is a flow control valve that maintains the supply pressure.

  The wastegate valve opens and closes the bypass passage port that communicates with the discharge part provided at the inflow part.If the inflowing exhaust gas exceeds a certain amount, the valve is opened to allow excess exhaust gas to pass through the turbine rotor. Without draining. The flow control valve opens and closes one passage port when the exhaust gas passage to the turbine rotor is divided into two, and closes the valve to reduce the capacity of the turbine when the amount of inflowing exhaust gas decreases. When the amount of exhaust gas flowing in is large, the valve is opened to increase the turbine capacity.

  The wastegate valve and the flow control valve are normally supported by a shaft portion whose shaft portion is rotatably connected to the inner side and the outer side of the turbine housing, and can be rotated from the outer side of the turbine housing. Thus, the exhaust gas flow is controlled by opening and closing the valve. Since such a valve member is directly exposed to exhaust gas at 800 ° C. or higher, the clearance between the shaft portion of the valve member and the bearing portion is a general clearance between the shaft and the bearing to prevent seizure due to thermal expansion or thermal deformation. Larger than For this reason, there has been a problem that a part of the exhaust gas flowing into the turbine housing flows out to the atmosphere from the gap between the shaft portion and the bearing portion due to a pressure difference between the inside and outside of the turbine housing.

  For this problem, an exhaust gas sealing structure in which a washer having an inner diameter smaller than the inner diameter of the bearing portion is used as a sealing member and fitted to the shaft portion between the valve member and the bearing portion (see, for example, Patent Document 1). It has been known. According to this seal structure, the shaft portion can be thermally expanded by the temperature of the exhaust gas to reduce the gap between the shaft portion and the seal member, and the valve member and the seal member can be pressed against the bearing portion by the pressure of the exhaust gas. Thereby, the amount of exhaust gas flowing out from the gap between the shaft portion and the bearing portion can be reduced.

  Further, the exhaust gas outflow passage is bent by arranging a seal member fitted to the inner peripheral surface of the bearing portion and a seal member fitted to the outer peripheral surface of the shaft portion of the valve member adjacent to each other in the axial direction of the shaft portion. Also, an exhaust gas seal structure that is long and reduces the amount of exhaust gas flowing out to the outside (for example, see Patent Document 2) has been studied.

JP-A-8-334030 JP-A-5-248253

  However, in the conventional turbocharger, the shaft portion may be inclined in the bearing portion due to the vibration of the engine, the actuator load for controlling the valve member, or the like. Therefore, in the seal structures described in Patent Documents 1 and 2, the gap between the shaft portion and the seal member is small, and the seal member follows the inclination of the shaft portion. There was a problem that a gap was generated and exhaust gas flowed out from this gap.

  Further, the seal structures described in Patent Documents 1 and 2 are not employed in a turbocharger having a variable turbine capacity. Therefore, the seal structure of the flow control valve specific to the turbocharger with variable turbine capacity has not been studied. That is, since the flow control valve is provided in the exhaust gas passage through which the exhaust gas flows, the ambient temperature and pressure are higher than those of the wastegate valve provided on the bypass passage side communicating with the exhaust portion. Further, the size of the flow control valve is larger than that of the wastegate valve due to its role, and the shaft portion and the bearing portion are set to be larger in accordance with this. As described above, in the flow control valve, the clearance between the shaft portion and the bearing portion is larger than that of the wastegate valve, and the pressure difference with the outside is also large, so the amount of exhaust gas flowing out to the outside is larger. ing. Therefore, the reduction width of the outflow amount of exhaust gas required for the flow control valve is larger than the reduction width of the waste gate valve, and there has been a demand for an exhaust gas seal structure that can handle such a flow control valve. .

  The present invention has been devised in view of the above problems, and in a turbocharger having a variable turbine capacity, a shaft portion of a valve member that controls the turbine capacity, and a bearing portion that rotatably supports the shaft portion. It is an object of the present invention to provide an exhaust gas seal structure for a turbocharger that can reduce the amount of exhaust gas flowing out from the gap.

In order to achieve the above object, a first characteristic configuration of a turbocharger according to the present invention includes a turbine rotor, a first scroll portion, and a second scroll portion, and a turbine in which an exhaust gas passage in which the turbine rotor is disposed is formed. The housing is disposed in a space communicating with the exhaust gas passage on the upstream side of the turbine rotor, and a bearing portion communicating the inner side and the outer side of the turbine housing, and is rotatably inserted and supported by the bearing portion. A valve member that controls communication between the first scroll portion and the second scroll portion by rotating the shaft portion, and allows the exhaust gas to flow into the exhaust gas passage, and the valve member In the turbocharger in which the communication between the first scroll portion and the second scroll portion is controlled to make the turbine capacity variable, the inner diameter of the bearing portion is A seal member that has a small inner diameter and is relatively displaceable relative to the shaft portion, is inserted into the shaft portion on each of the inner side and the outer side of the turbine housing, and the outer side seal member is inserted into the bearing portion. An urging means for urging the side surface is provided . The urging means is externally attached to the shaft portion on the outside of the turbine housing, and extends between the flange portion provided on the shaft portion and the seal member. It is in the point which is the arranged coil spring .

That is, according to this configuration, since the inflow pressure of the exhaust gas before flowing into the turbine rotor acts on the seal member inserted into the shaft portion on the inner side of the turbine housing, the seal member is supported by the pressure of the exhaust gas. The seal member that is urged to the side surface of the portion and is inserted into the shaft portion on the outside side is urged to the side surface of the bearing portion by the urging means comprising a coil spring . Since the coil spring is inserted into the shaft portion on the outer side of the turbine housing, the influence on the temperature of the exhaust gas can be reduced.
In addition, the seal member inserted through the shaft portion has an inner diameter smaller than the inner diameter of the bearing portion, and is relatively displaceable with the shaft portion. Therefore, even when the shaft portion is inclined, it is possible to follow the shaft portion. Absent.
For this reason, when the exhaust gas flows out to the outside, the exhaust gas can be surely passed through the gap between the shaft portion and the seal member, so that the exhaust gas outlet passage can be made small.

Further, since the seal member is inserted into the shaft portion on each of the inner side and the outer side of the turbine housing, the pressure between the inside of the turbine housing and the bearing portion, and between the bearing portion and the outside of the turbine housing, respectively. A difference can be made. For this reason, each pressure difference can be made smaller than the pressure difference between the inside and the outside of the turbine housing.
Therefore, it is possible to make it more difficult for the exhaust gas to flow out from the gap between the shaft portion and the bearing portion, and when a relatively high exhaust gas inflow pressure acts, that is, in the space communicating with the exhaust gas passage on the upstream side of the turbine rotor, Even in the valve member in which the shaft portion is disposed, the amount of exhaust gas leaking from the valve member can be reduced.

A second characteristic configuration of a turbocharger exhaust gas seal structure according to the present invention includes a turbine rotor, a first scroll portion, a second scroll portion, a turbine housing in which an exhaust gas passage in which the turbine rotor is disposed is formed, A bearing portion that is disposed in a space communicating with the exhaust gas passage upstream of the turbine rotor and that communicates the inner side and the outer side of the turbine housing; and a shaft portion that is rotatably inserted and supported by the bearing portion. A valve member that controls communication between the first scroll portion and the second scroll portion by rotation of the shaft portion, and allows the exhaust gas to flow into the exhaust gas passage, and the valve member to In a turbocharger in which communication between one scroll portion and the second scroll portion is controlled to make the turbine capacity variable, the turbocharger is smaller than the inner diameter of the bearing portion. A plurality of sealing members having a large inner diameter and freely displaceable relative to the shaft portion are inserted into the shaft portion on the outside of the turbine housing, and biasing means for biasing the seal member to the side surface of the bearing portion The biasing means is a coil spring that is externally attached to the shaft portion on the outside of the turbine housing and is disposed across the flange portion provided on the shaft portion and the seal member. .

In other words, according to this configuration, a plurality of seal members inserted into the shaft portion on the outer side of the turbine housing are urged toward the side surface of the bearing portion by the urging means including a coil spring . Since the coil spring is inserted into the shaft portion on the outer side of the turbine housing, the influence on the temperature of the exhaust gas can be reduced.
In addition, the seal member inserted through the shaft portion has an inner diameter smaller than the inner diameter of the bearing portion, and is relatively displaceable with the shaft portion. Therefore, even when the shaft portion is inclined, it is possible to follow the shaft portion. Absent.
For this reason, when the exhaust gas flows out to the outside, the exhaust gas can be surely passed through the gap between the shaft portion and the seal member, so that the exhaust gas outlet passage can be made small.

Further, since a plurality of seal members are inserted into the shaft portion, the exhaust gas outflow passage can be complicated and lengthened.
Therefore, it is possible to make it difficult for the exhaust gas to flow out from the gap between the shaft portion and the bearing portion, and when the relatively high exhaust gas inflow pressure acts, that is, the bearing portion in the space communicating with the exhaust gas passage on the upstream side of the turbine rotor. Even in the valve member in which the shaft portion is disposed, the amount of exhaust gas leaking from the valve member can be reduced.

A third characteristic configuration of the exhaust gas seal structure of the turbocharger according to the present invention includes a turbine rotor, a first scroll portion, a second scroll portion, a turbine housing in which an exhaust gas passage in which the turbine rotor is disposed is formed, A bearing portion that is disposed in a space communicating with the exhaust gas passage upstream of the turbine rotor and that communicates the inner side and the outer side of the turbine housing; and a shaft portion that is rotatably inserted and supported by the bearing portion. A valve member that controls communication between the first scroll portion and the second scroll portion by rotation of the shaft portion, and allows the exhaust gas to flow into the exhaust gas passage, and the valve member to In a turbocharger in which communication between one scroll portion and the second scroll portion is controlled to make the turbine capacity variable, the turbocharger is smaller than the inner diameter of the bearing portion. At least one seal member that has an inner diameter and is relatively displaceable relative to the shaft portion is inserted into the shaft portion on the inner side of the turbine housing, and a plurality of seal members are inserted into the shaft portion on the outer side of the turbine housing. And an urging means for urging the seal member on the outer side toward the side surface of the bearing portion, and the urging means is extrapolated to the shaft portion on the outer side of the turbine housing and is attached to the shaft portion. The coil spring is arranged over the provided flange portion and the seal member .

That is, according to this configuration, since the inflow pressure of the exhaust gas before flowing into the turbine rotor acts on the seal member inserted into the shaft portion on the inner side of the turbine housing, the seal member is supported by the pressure of the exhaust gas. The seal member that is urged to the side surface of the portion and is inserted into the shaft portion on the outside side is urged to the side surface of the bearing portion by the urging means comprising a coil spring . Since the coil spring is inserted into the shaft portion on the outer side of the turbine housing, the influence on the temperature of the exhaust gas can be reduced.
In addition, the seal member inserted through the shaft portion has an inner diameter smaller than the inner diameter of the bearing portion, and is relatively displaceable with the shaft portion. Therefore, even when the shaft portion is inclined, it is possible to follow the shaft portion. Absent.
For this reason, when the exhaust gas flows out to the outside, the exhaust gas can be surely passed through the gap between the shaft portion and the seal member, so that the exhaust gas outlet passage can be made small.

  Further, since the seal member is inserted into the shaft portion on each of the inner side and the outer side of the turbine housing, the pressure between the inside of the turbine housing and the bearing portion, and between the bearing portion and the outside of the turbine housing, respectively. A difference can be made. For this reason, each pressure difference can be made smaller than the pressure difference between the inside and the outside of the turbine housing.

Furthermore, since a plurality of seal members are inserted into the shaft portion on the outside of the turbine housing, the exhaust gas outflow passage can be complicated and lengthened.
Therefore, it is possible to make it more difficult for the exhaust gas to flow out from the gap between the shaft portion and the bearing portion, and when a relatively high exhaust gas inflow pressure acts, that is, in the space communicating with the exhaust gas passage on the upstream side of the turbine rotor, Even in the valve member in which the shaft portion is disposed, the amount of exhaust gas leaking from the valve member can be reduced.

A fourth characteristic configuration of the exhaust gas seal structure for a turbocharger according to the present invention is that it includes second urging means for urging the inner seal member toward the side surface of the bearing portion.

  That is, according to this configuration, even when the pressure of the exhaust gas inside the turbine housing is low, the seal member inserted through the shaft portion on the inner side of the turbine housing can be reliably urged to the side surface of the bearing portion. it can.

[First embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
The turbocharger according to the present embodiment is a turbocharger having a variable turbine capacity (hereinafter simply referred to as “turbocharger”), and as shown in FIG. 1, a turbine unit 100 including the turbine rotor 1 and a compressor rotor (illustrated). Not provided) and a connecting portion 300 including a connecting shaft 301 that connects the turbine rotor 1 and the compressor rotor. The turbocharger rotates the turbine rotor 1 with the exhaust gas of the engine (not shown), rotates the compressor rotor connected to the turbine rotor 1 to compress the air, and supplies the compressed air to the engine.

As shown in FIGS. 1 and 2, the turbine unit 100 includes a turbine housing 2 that houses the turbine rotor 1, an inner scroll portion (first scroll portion) 3a, and an outer scroll portion (second scroll portion) 3b. A partitioned exhaust gas passage 3, a flow control valve 4 and a waste gate valve 5 as valve members are provided. The exhaust gas flowing into the turbine housing 2 is sent to the turbine rotor 1 through the exhaust gas passage 3.
A turbine rotor 1 is disposed at the center of the turbine housing 2 that forms the exhaust gas passage 3. The exhaust gas flows into the exhaust gas passage 3 from the outer peripheral side of the turbine housing 2, and the turbine rotor 2 starts from the center of the turbine housing 2. 1 flows out of the turbine housing 2 through 1. In addition, as shown in FIG. 2, the partition between the inner peripheral scroll portion 3 a and the outer peripheral scroll portion 3 b is partially divided into a partition portion 15 that partitions the inner peripheral scroll portion 3 a and the outer peripheral scroll portion 3 b, and the inner peripheral scroll portion. 3a and the communication part 16 which connects the outer periphery scroll part 3b become a form arrange | positioned alternately. Thus, the inner scroll portion 3a and the outer scroll portion 3b are basically always in communication.

  The flow control valve 4 is a valve member for controlling the communication between the inner peripheral scroll portion 3a and the outer peripheral scroll portion 3b to change the turbine capacity, and according to the amount of exhaust gas flowing into the turbine housing 2. The inlet of the outer periphery scroll part 3b provided in the wall part which partitions off the inner periphery scroll part 3a and the outer periphery scroll part 3b is controlled to open and close. When the amount of inflow of exhaust gas is small, the flow control valve 4 closes the inlet of the outer scroll part 3b and causes the exhaust gas to flow mainly into the inner scroll part 3a to reduce the turbine capacity. On the other hand, when the inflow amount of exhaust gas increases, the inlet of the outer peripheral scroll portion 3b is opened, and sufficient exhaust gas flows into both the inner peripheral scroll portion 3a and the outer peripheral scroll portion 3b to increase the turbine capacity. The flow control valve 4 is arranged in a space communicating with the exhaust gas passage 3 upstream of the turbine rotor 1 as shown in FIG. More specifically, as shown in FIG. 3, on the upstream side of the turbine rotor 1 in the exhaust gas passage 3, a bearing portion 7 is provided so that the inner side and the outer side of the turbine housing 2 forming the outer peripheral scroll portion 3 b communicate with each other. The shaft 6 serving as a shaft portion is rotatably inserted and supported by the bearing portion 7, and the flow control valve 4 is connected to the shaft 6 via the arm 8 in the outer scroll portion 3 b. Yes. Here, as described above, since the outer peripheral scroll portion 3b and the inner peripheral scroll portion 3a are always in communication with each other by the connecting portion 16, the flow control is provided in the space where the bearing portion 7 and the shaft 6 are disposed. Regardless of whether the valve 4 is open or closed, the inflow pressure of the exhaust gas before flowing into the turbine rotor 1 from the engine acts. Therefore, since a relatively high pressure always acts on the bearing portion 7 and the shaft 6, a more excellent exhaust gas seal structure is required.

  The wastegate valve 5 controls opening and closing of the inlet of the bypass passage 5a that communicates with the exhaust gas exhaust port in accordance with the amount of exhaust gas flowing into the turbine housing 2. The wastegate valve 5 opens the inlet of the bypass passage 5a when the inflow amount of the exhaust gas exceeds a certain level, and discharges excess exhaust gas without passing through the turbine rotor, thereby reducing the pressure of the air supplied to the engine. Keep almost constant.

In the present embodiment, an example in which the exhaust gas seal structure of a turbocharger according to the present invention is applied to a flow control valve 4 as shown in FIG. 3 will be described.
The turbocharger exhaust gas seal structure according to the present embodiment includes a shaft 6 that is a shaft portion of the flow control valve 4 and a bearing portion 7 on which the shaft 6 is rotatably inserted and supported. 7, a washer 10 inserted through the shaft 6 on each of the inner side and the outer side of the turbine housing 2 is urged by a coil spring 11. Furthermore, since the inflow pressure of the exhaust gas before flowing into the turbine rotor 1 acts on the internal washer 10, the internal washer 10 is also urged to the side surface of the bearing portion by the exhaust gas pressure. . Thereby, each washer 10 and the side surface of the bearing portion 7 are brought into close contact with each other, and when the exhaust gas flows out to the outside, the exhaust gas can be passed through the gap between the shaft 6 and the washer 10.

  An arm 8 connected to the flow control valve 4 is fitted on the shaft 6 on the inner side of the turbine housing 2, and a lever 9 having a flange portion 9a is fitted on the outer side. A driving device (not shown) is connected to the lever 9, and the shaft 6 is rotated via the lever 9 by this driving device, so that the flow control valve 4 is controlled to open and close.

  The washer 10 is an example of a seal member in the present invention. The inner diameter of the washer 10 is set to be smaller than the inner diameter of the bearing portion 7, and a constant gap is generated when the shaft is inserted into the shaft body. Displaceable. Thereby, a gap generated when the washer 10 is inserted into the shaft 6 can be made smaller than a gap between the shaft 6 and the bearing portion 7, and the washer 10 does not follow the shaft 6 even when the shaft 6 is inclined. You can

  In addition, since the washer 10 is exposed to high-temperature exhaust gas, it is preferable that the washer 10 is made of a heat-resistant material exemplified by stainless steel, inconel, ceramics, etc. that can withstand the exhaust gas temperature. Further, in order to keep the gap between the washer 10 and the shaft 6 substantially constant from the low temperature to the high temperature, the material having the same or higher characteristic coefficient than the high temperature average linear expansion coefficient of the material constituting the shaft 6 is used. It is preferable. The material constituting the shaft 6 is the same as that of the conventional one.

In the present embodiment, the washer 10 has the same inner diameter as an example. However, since the ambient temperature differs between the inner side and the outer side of the turbine housing 2, the inner washer is made to correspond to each temperature. It is also possible to provide the inner diameter of 10 and the outer diameter of the washer 10 on the outer side different from each other. The same applies to the material constituting the washer 10, and the material constituting the inner washer 10 and the material constituting the outer washer may be the same or different, and are resistant to the respective temperatures. A suitable material may be selected as appropriate.
In the present embodiment, an example in which one washer 10 inserted into the shaft 6 on the inner side of the turbine housing 2 and one washer 10 inserted on the outer side is provided, but there is no particular limitation. A plurality can be provided on one side or both sides.

The coil spring 11 is an example of an urging means in the present invention. The coil spring 11 is compressed and disposed over the flange portion 9a of the lever 9 and the washer 10 on the outside. By energizing the shaft 6 to the outside of the turbine housing 2 via the flange portion 9a on one side of the coil spring 11, the washer 10 disposed between the arm 8 and the bearing portion 7 is energized. At the same time, the outer washer 10 is urged to the side surface of the bearing portion 7 through the dust cover 12 provided as a dust guard on the other side of the coil spring 11. Thereby, the washer 10 and the side surface of the bearing part 7 can be stuck.
Since the coil spring 11 in this embodiment urges the shaft 6 via the flange portion 9a, the washer 10 can be securely brought into close contact with the bearing portion 7, and the vibration of the engine and the valve member are controlled. It is also possible to suppress the tilting of the shaft portion due to an actuator load or the like.
Further, since the coil spring 11 is disposed on the outside of the turbine housing, the influence on the temperature of the exhaust gas can be reduced, and thermal expansion, thermal deformation, and the like can be suppressed. This also increases the range of selection of the material constituting the coil spring 11.

The coil spring 11 brings the washer 10 on the outer side into close contact with the side surface of the bearing portion 7 and prevents the exhaust gas from flowing out from the gap, so that the pressure of the exhaust gas flowing out from the gap between the shaft 6 and the bearing portion 7 is larger. It is energized by the energizing force.
Further, in order to always hold the inner washer 10 between the arm 8 and the side surface of the bearing portion 7, the coil spring 11 is applied with an urging force capable of suppressing the vibration of the shaft 6 due to the vibration of the engine. More preferably. However, even if the vibration of the shaft 6 is not completely suppressed by the coil spring 11, the exhaust gas pressure inside the turbine housing is increased and the washer 10 is moved to Can be biased to the side. Further, when the engine speed is such that the pressure of the exhaust gas becomes small, the vibration becomes small, so that the washer 10 can be urged to the side surface of the bearing portion 7 via the arm 8 by the coil spring 11.
In this embodiment, the case where the outer washer 10 is urged to the side surface of the bearing portion 7 by the coil spring 11 and the inner side washer 10 is urged to the side surface of the bearing portion 7 at the same time is illustrated. The washer 10 may be urged toward the side surface of the bearing portion 7 only by the pressure of the exhaust gas inside the turbine housing 2. In this case, if the pressure of the exhaust gas becomes low, it becomes difficult to urge the washer 10, but there is no problem because the outflow pressure of the exhaust gas also decreases.

  The dust cover 12 has a conventionally known shape and material and is not particularly limited. There is no problem even if it is not used.

If the exhaust gas seal structure of the turbocharger configured in this way is used, the exhaust gas can be surely passed through the gap between the shaft 6 and the washer 10 when the exhaust gas flows out. Can be small.
Further, a pressure difference can be generated between the inside of the turbine housing 2 and the bearing portion 7 and between the bearing portion 7 and the outside of the turbine housing 2. For this reason, each pressure difference can be made smaller than the pressure difference between the inside and the outside of the turbine housing 2.
Therefore, it is possible to make it difficult for the exhaust gas to flow out from the gap between the shaft 6 and the bearing portion 7, and to flow out even when a relatively high inflow pressure of the exhaust gas before flowing into the turbine rotor 1 acts. The amount of exhaust gas can be reduced.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described. In the turbocharger exhaust gas seal structure according to the present embodiment, three washers 10 are provided on the shaft 6 only on the outside of the turbine housing 2 as shown in FIG. These washers 10 are urged against the side surface of the bearing portion 7 by a coil spring 11. Thereby, the washer 10 on the bearing portion 7 side is brought into close contact with the side surface of the bearing portion 7 and the washers 10 are brought into close contact with each other. Other configurations are the same as those in the first embodiment.

  An example of the exhaust gas outflow passage obtained by the exhaust gas seal structure of the turbocharger according to the present embodiment will be described. The washer 10 according to the present embodiment is eccentric in the axial direction of the shaft 6 as shown in FIG. 5, for example, due to engine vibration or the like. For this reason, each gap 13 between the shaft 6 and the washer 10 is reduced by the overlap of the washers 10, and the exhaust gas hardly passes through the gap 13 a generated by the overlap of the washers 10. Further, even if the exhaust gas passes through the relatively large gap 13 between the one washer 10 and the shaft 6, in order to pass through the gap 13 between the second washer 10 and the shaft 6, Passing while moving in the direction, the outflow passage of the exhaust gas can be complicated and lengthened. Therefore, by providing a plurality of washers 10, it is possible to make it difficult for the exhaust gas to flow out from the gap between the shaft 6 and the bearing portion 7, and a relatively high exhaust gas inflow pressure before flowing into the turbine rotor 1 acts. Even in this case, the amount of exhaust gas flowing out can be reduced.

  In the present embodiment, the case where three washers 10 are used is illustrated, but the number of washers 10 is not limited as long as two or more washers 10 are provided. Further, in the present embodiment, an example in which the washer 10 has the same shape and the same material is used, but a plurality of washers 10 on the outer side may have different shapes and materials.

[Third embodiment]
Next, a third embodiment according to the present invention will be described. In the exhaust gas seal structure of the turbocharger according to this embodiment, as shown in FIG. 6, three washers 10 are provided on the outer side of the turbine housing 2, and one washer 10 is provided on the inner side. The washer 10 is in close contact with the side surface of the bearing portion 7 and the adjacent washers 10 are in close contact with each other. Other configurations are the same as those in the first embodiment.

With such a configuration, a pressure difference is generated between the inside of the turbine housing 2 and the bearing portion 7 and between the bearing portion 7 and the outside of the turbine housing 2, and the respective pressure differences are generated by the turbine housing. The pressure difference between the inside and the outside can be made smaller.
Furthermore, the exhaust gas outflow passage can be complicated and lengthened on the outside of the turbine housing 2.
Therefore, it is possible to make it difficult for the exhaust gas to flow out from the gap between the shaft 6 and the bearing portion 7, and to flow out even when a relatively high inflow pressure of the exhaust gas before flowing into the turbine rotor 1 acts. The amount of exhaust gas can be reduced.

[Other Embodiments]
In the first embodiment and the third embodiment, the example in which the inner washer 10 is urged by the pressure of the exhaust gas and the coil spring 11 is shown. A second urging means may be provided so that a hook is provided on the side surface and the washer 10 is engaged and urged. According to this, even when the pressure of the exhaust gas is low and the vibration of the shaft 6 is large, the inner washer 10 can be reliably brought into close contact with the side surface of the bearing portion 7.

In each of the above embodiments, the example in which the shaft 6 is urged has been shown, but it is not necessary to urge it separately.
Moreover, in each said embodiment, although the example which used the washer 10 as a sealing member was shown, it is not restricted to this.
In each of the above-described embodiments, the example in which the coil spring 11 is used as the urging means has been described. However, the present invention is not limited to this, and a disc spring or the like can be used.

  The turbocharger exhaust gas seal structure according to the present invention is applied to the flow control valve 4, but the same effect can be obtained when applied to the wastegate valve 5. The wastegate valve 5 has a lower ambient temperature than the flow control valve 4 and a small pressure difference from the outside of the turbine housing 2, so it is clear that the exhaust gas outflow can be reduced by the exhaust gas sealing structure according to the present invention. It is.

1 is an overall schematic diagram showing a partial cross section of a turbocharger according to a first embodiment of the present invention. AA sectional view of FIG. BB sectional view of FIG. Sectional drawing which shows the exhaust gas seal structure which concerns on 2nd embodiment of this invention. The figure explaining the passage shape of the exhaust gas in the exhaust gas seal structure concerning a second embodiment of the present invention Sectional drawing which shows the exhaust gas seal structure which concerns on 3rd embodiment of this invention.

Explanation of symbols

1 Turbine rotor 2 Turbine housing 4 Valve member (flow control valve)
5 Valve member (waist gate valve)
6 Shaft (shaft)
7 Bearing 9 Lever 9a Flange 10 Seal member (washer)
11 Biasing means (coil spring)

Claims (4)

A turbine rotor,
A turbine housing having a first scroll part and a second scroll part, in which an exhaust gas passage in which the turbine rotor is disposed is formed;
A bearing portion that is disposed in a space communicating with the exhaust gas passage upstream of the turbine rotor and that communicates the inner side and the outer side of the turbine housing; and a shaft portion that is rotatably inserted and supported by the bearing portion. A valve member that controls communication between the first scroll portion and the second scroll portion by rotation of the shaft portion,
In the turbocharger that causes exhaust gas to flow into the exhaust gas passage and controls the communication between the first scroll portion and the second scroll portion by the valve member to make the turbine capacity variable.
A seal member having an inner diameter smaller than the inner diameter of the bearing portion and freely displaceable relative to the shaft portion is inserted into the shaft portion on each of the inner side and the outer side of the turbine housing,
There is provided an urging means for urging the seal member on the outer side toward the side surface of the bearing portion, and the urging means is externally attached to the shaft portion and provided on the shaft portion on the outer side of the turbine housing. An exhaust gas seal structure for a turbocharger, which is a coil spring disposed over the flange portion and the seal member . A turbine rotor,
A turbine housing having a first scroll part and a second scroll part, in which an exhaust gas passage in which the turbine rotor is disposed is formed;
A bearing portion that is disposed in a space communicating with the exhaust gas passage upstream of the turbine rotor and that communicates the inner side and the outer side of the turbine housing; and a shaft portion that is rotatably inserted and supported by the bearing portion. A valve member that controls communication between the first scroll portion and the second scroll portion by rotation of the shaft portion,
In the turbocharger that causes exhaust gas to flow into the exhaust gas passage and controls the communication between the first scroll portion and the second scroll portion by the valve member to make the turbine capacity variable.
A plurality of seal members having an inner diameter smaller than the inner diameter of the bearing portion and capable of relative displacement with the shaft portion are inserted into the shaft portion on the outer side of the turbine housing,
An urging means for urging the seal member to the side surface of the bearing portion is provided , and the urging means is externally attached to the shaft portion on the outer side of the turbine housing, and a flange portion provided on the shaft portion. And an exhaust gas seal structure of a turbocharger that is a coil spring disposed over the seal member . A turbine rotor,
A turbine housing having a first scroll part and a second scroll part, in which an exhaust gas passage in which the turbine rotor is disposed is formed;
A bearing portion that is disposed in a space communicating with the exhaust gas passage upstream of the turbine rotor and that communicates the inner side and the outer side of the turbine housing; and a shaft portion that is rotatably inserted and supported by the bearing portion. A valve member that controls communication between the first scroll portion and the second scroll portion by rotation of the shaft portion,
In the turbocharger that causes exhaust gas to flow into the exhaust gas passage and controls the communication between the first scroll portion and the second scroll portion by the valve member to make the turbine capacity variable.
At least one seal member having an inner diameter smaller than the inner diameter of the bearing portion and capable of relative displacement with the shaft portion is inserted into the shaft portion on the inner side of the turbine housing, and on the outer side of the turbine housing. A plurality of the shafts are inserted,
There is provided an urging means for urging the seal member on the outer side toward the side surface of the bearing portion, and the urging means is externally attached to the shaft portion and provided on the shaft portion on the outer side of the turbine housing. An exhaust gas seal structure for a turbocharger, which is a coil spring disposed over the flange portion and the seal member . The exhaust gas seal structure for a turbocharger according to claim 1 or 3 , further comprising second urging means for urging the seal member on the inner side toward the side surface of the bearing portion.

Images