JP7299137B2 - supercharger - Google Patents

Description

The present invention relates to superchargers.

A nozzle ring, a shroud ring provided at a position spaced apart from and facing the nozzle ring in the axial direction of the turbine impeller, and a plurality of variable nozzles disposed between the opposing surface of the nozzle ring and the opposing surface of the shroud ring is known.

In this variable displacement turbocharger, a support ring is disposed on the opposite side of the nozzle ring, and a plurality of protruding pieces are integrally formed on the inner peripheral edge of the support ring at intervals in the circumferential direction. It is This allows the support ring to move in the radial direction relative to the nozzle ring while the plurality of protruding pieces and the outer peripheral edge of the nozzle ring are pressed against each other. In addition, the outer periphery of the support ring has a low member temperature due to cooling by the bearing housing (see, for example, Patent Document 1).

JP 2013-253519 A

By the way, since the variable nozzle (hereinafter referred to as nozzle vane) is arranged in the exhaust flow path, the opposing surface of the nozzle ring (hereinafter referred to as nozzle plate) is exposed to the exhaust gas. Therefore, the heat of the exhaust directly reaches the nozzle plate, and the nozzle plate expands due to the heat of the exhaust.

On the other hand, since the projecting piece of the support ring is also exposed to the exhaust gas, the heat of the exhaust gas directly reaches the projecting piece. However, since the projecting piece is integrally formed with the support ring, the heat reaching the projecting piece is mitigated by the cooling provided by the bearing housing. Therefore, an expansion difference occurs between the projecting piece and the nozzle plate. When the difference in expansion occurs, relative slippage occurs between the protruding piece and the nozzle plate on the pressure contact surface between the protruding piece and the nozzle plate, and the pressure contact surface is worn. As the wear of the pressure contact surface progresses, the support ring may no longer be able to support the nozzle plate via the projecting piece, resulting in malfunction of the nozzle vane.

Accordingly, an object of the present invention is to suppress poor support of the nozzle plate.

A turbocharger according to the present invention includes a ring-shaped nozzle plate that supports one side of a nozzle vane arranged in an exhaust flow path on a first surface through which the exhaust flows ; a support shaft supported from a second surface opposite to the surface ; and a bearing housing supporting the support shaft parallel to and offset from the turbine shaft. An opening is provided to hold the support shaft with a gap therebetween, and the opening has a clearance inside the nozzle plate in the radial direction to avoid interference with the support shaft.

According to the present invention, poor support of the nozzle plate can be suppressed.

FIG. 1 is an example of a cross-sectional view of a turbocharger. FIG. 2(a) is an example of a plan view of the variable nozzle unit. FIG.2(b) is an example of the top view of the connection structure which concerns on 1st Embodiment. FIG. 3A shows an example of the nozzle plate before expansion. FIG. 3(b) is an example after expansion of the nozzle plate. FIG. 4(a) is an example of a plan view of a connection structure according to the second embodiment. FIGS. 4B and 4C are other examples of plan views of the connection structure according to the second embodiment. FIG. 5(a) is a partially enlarged view of the vicinity of the nozzle according to the third embodiment. FIG. 5(b) is an example of a YY section near the support shaft. FIG. 5(c) is an example of a ZZ section near the support shaft.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is an example of a cross-sectional view of turbocharger 100 . The turbocharger 100 is a variable displacement (variable nozzle) turbocharger. The turbocharger 100 includes a compressor 10, a bearing section 20, and a turbine 30, as shown in FIG. A bearing section 20 connects the compressor 10 and the turbine 30 .

Compressor 10 includes a compressor housing 11 . Bearing portion 20 includes a bearing housing 21 . Turbine 30 includes a turbine housing 31 . Bearing housing 21 is arranged substantially in the center of turbocharger 100 . The compressor housing 11, the bearing housing 21 and the turbine housing 31 are assembled integrally. Specifically, the compressor housing 11 and the turbine housing 31 are assembled on both sides of the bearing housing 21, respectively.

A compressor wheel 12 is accommodated in the compressor housing 11 . Compressor wheel 12 is fixed to one end of turbine shaft 32 by nut 13 . Compressor wheel 12 rotates integrally with turbine shaft 32 . Compressor wheel 12 is provided with a plurality of compressor blades. As the compressor wheel 12 rotates, the fresh air is accelerated radially outward by centrifugal force and compressed by the compressor blades. Therefore, as shown in FIG. 1, when fresh air is introduced into the central portion of the compressor housing 11, this fresh air is compressed by the compressor blades of the rotating compressor wheel 12, and this compressed fresh air is supplied to the turbo. It is discharged to the outside of charger 100 . Specifically, this compressed fresh air is discharged toward the engine through the intake pipe. Thus, fresh air circulates in the compressor 10 .

A bearing housing 21 supports a turbine shaft 32 . The bearing housing 21 contains cold water passages 23 and is water cooled. Various bearings are provided in the bearing housing 21 . For example, a thrust bearing for receiving the thrust direction load of the turbine shaft 32 and a floating bearing for holding the radial direction load of the turbine shaft 32 are provided. The bearing is lubricated with oil or the like. Turbine shaft 32 is supported by these various bearings.

A turbine wheel 33 is accommodated in the turbine housing 31 . The turbine wheel 33 may also be called a turbine impeller. The other end of the turbine shaft 32 is connected and fixed to the turbine wheel 33 . The turbine wheel 33 is rotationally driven by the exhaust discharged from the engine. Thereby, the turbine wheel 33 generates rotational power. This rotational power drives the compressor wheel 12 through the turbine shaft 32 to produce compressed fresh air. As mentioned above, the compressed fresh air is discharged towards the engine.

A link chamber 50 is formed between the turbine housing 31 and the bearing housing 21 . A variable nozzle unit 34 is arranged in the link chamber 50 . The variable nozzle unit 34 includes a ring-shaped nozzle plate 34a, a plurality of nozzle vanes 34b, a ring-shaped unison ring 34c, and the like. The nozzle plate 34a is supported by a T-shaped support shaft 22. As shown in FIG. The support shaft 22 is axially supported in parallel with the turbine shaft 32 by the bearing housing 21 and biased toward the compressor housing 11 by a coil spring.

The nozzle plate 34 a is arranged at a position facing the shroud portion 31 a of the turbine housing 31 so as to abut against the turbine housing 31 . That is, the nozzle plate 34a is arranged on the bearing housing 21 side. The nozzle plate 34a and the shroud portion 31a are arranged to face each other to form a nozzle N through which the exhaust gas flows as a flow path. One side of the nozzle vane 34b is supported by the nozzle plate 34a, and the other side of the nozzle vane 34b is supported by the shroud portion 31a. The nozzle vanes 34b adjust the flow cross-section at the nozzles N to make the capacity of the turbine 30 variable.

Next, details of the variable nozzle unit 34 described above will be described with reference to FIGS.

FIG. 2A is an example of a plan view of the variable nozzle unit 34. FIG. FIG. 2B is an example of a plan view of the connecting structure 34d according to the first embodiment. 2A shows the variable nozzle unit 34 viewed from the compressor 10 side. As described above, the variable nozzle unit 34 includes the nozzle plate 34a, the plurality of nozzle vanes 34b, the unison ring 34c, and the like. Not shown.

A plurality of vane shafts 34f are arranged at substantially equal intervals in the circumferential direction on the circumference centered on the central axis L1 of the nozzle plate 34a. Each vane shaft 34f extends substantially parallel to the central axis L1 and is rotatably inserted through the nozzle plate 34a. A base end portion of an arm 34e for driving the nozzle vane 34b is fixed to an end portion of each vane shaft 34f protruding from the nozzle plate 34a toward the bearing housing 21 side.

A plurality of recesses 34g are formed on the outer peripheral surface of the unison ring 34c. The tips of the arms 34e are engaged with these recesses 34g. Unison ring 34c is rotated from the outside of turbocharger 100 via a link (not shown) or the like.

When the unison ring 34c is rotated around the central axis L1 via a link or the like from the outside of the turbocharger 100, the arms 34e engaged with the plurality of concave portions 34g of the unison ring 34c move the vane shaft 34f. They are rotated (opened and closed) in a synchronized state about the center. The passage cross section of the nozzle N is changed by changing the opening degree of the nozzle vane 34b based on the rotation of each vane shaft 34f. Then, the flow velocity or flow rate of the exhaust gas supplied to the turbine wheel 33 through between the two adjacent nozzle vanes 34b is adjusted.

Here, a connecting structure 34d is arranged between at least one of two adjacent vane shafts 34f. The support shaft 22 is connected to the connecting structure 34d. As shown in FIG. 2(b), the connecting structure 34d includes a connecting portion 34α and an opening 34β. Both the connecting portion 34α and the opening 34β are U-shaped. Since FIG. 2(a) shows the variable nozzle unit 34 as seen from the compressor 10 side, both the connection portion 34α and the opening portion 34β of the connection structure 34d are provided at locations opposite to the nozzle N side. . That is, the connection portion 34α and the opening portion 34β are provided at different locations except for the nozzle N. As shown in FIG. As shown in FIG. 2B, the connecting portion 34α of the connecting structure 34d is connected to the shaft head portion 22a of the support shaft 22, and the opening 34β of the connecting structure 34d intervenes the shaft shaft portion 22b with a predetermined gap GP. hold. In particular, in the present embodiment, a clearance CL having a size equal to or larger than the radial gap GP interposed between the nozzle plate 34a and the shaft shaft portion 22b is provided radially inside the nozzle plate 34a. Since the connecting portion 34α is U-shaped, the inner side in the radial direction of the nozzle plate 34a is open. Thereby, the clearance CL becomes larger than the size of the gap GP.

Next, before and after expansion of the nozzle plate 34a will be described with reference to FIGS. 3(a) and 3(b).

FIG. 3A shows an example of the nozzle plate 34a before expansion. FIG. 3B shows an example after expansion of the nozzle plate 34a. In particular, FIGS. 3(a) and 3(b) show the XX section shown in FIG. 2(a). As shown in FIGS. 3A and 3B, both before and after the nozzle plate 34a expands radially outward, the connecting portion 34α of the connecting structure 34d of the nozzle plate 34a and the shaft shaft portion of the support shaft 22 22b, a predetermined gap GP is interposed. The size of the predetermined gap GP may be appropriately determined according to design, experiments, and the like. A clearance CL is provided radially inward of the shaft shaft portion 22b.

Here, as shown in FIG. 3(b), when the nozzle plate 34a expands radially outward, the connecting structure 34d of the nozzle plate 34a also expands radially outward. In particular, the connection structure 34d expands while the connection portion 34α of the connection structure 34d and the shaft head portion 22a of the support shaft 22 slide (while sliding). On the other hand, since the support shaft 22 is pivotally supported by the bearing housing 21, the center axis does not change, and the support shaft 22 remains stationary without following the expansion of the connecting structure 34d. As a result, the size of the gap GP expands in accordance with the expansion of the nozzle plate 34a compared to before the expansion of the nozzle plate 34a. Conversely, the size of the clearance CL is reduced as the nozzle plate 34a expands compared to before the expansion of the nozzle plate 34a.

Thus, even if the nozzle plate 34a expands radially outward, the clearance CL is provided radially inwardly of the nozzle plate 34a. Interference with portion 22b is avoided. That is, in the present embodiment, even if the nozzle plate 34a expands radially outward due to the heat of the exhaust gas, the expansion is allowed.

Further, if the nozzle plate 34a is directly fixed and restrained to the support shaft 22, and if the nozzle plate 34a expands, the stress corresponding to the expansion of the nozzle plate 34a is applied to the support shaft 22 in the nozzle plate 34a. and the nozzle plate 34a may deform from its fixed portion. As a result, the flatness of the nozzles N may not be maintained. However, in this embodiment, the nozzle plate 34a is indirectly supported by the support shaft 22 via the connection structure 34d, and the nozzle plate 34a is not directly fixed to the support shaft 22. Deformation can be avoided. That is, even if the nozzle plate 34a expands, the flatness of the nozzles N can be maintained, and the operation of the nozzle vanes 34b is not affected.

As described above, according to the first embodiment, the turbocharger 100 includes the ring-shaped nozzle plate 34 a, the support shaft 22 and the bearing housing 21 . The nozzle plate 34a supports one side of a nozzle vane 34b located on the nozzle N. As shown in FIG. The support shaft 22 supports the nozzle plate 34a. The bearing housing 21 axially supports the support shaft 22 in parallel with the turbine shaft 32 at different levels. In particular, the nozzle plate 34a has an opening 34β that holds the support shaft 22 through the gap GP at a location other than the nozzle N. contains a clearance CL that avoids As a result, poor support of the nozzle plate 34a can be suppressed without adopting another component such as a projecting piece. In particular, in this embodiment, the opening 34β is provided at a location other than the nozzle N. As shown in FIG. Therefore, the connecting structure 34d including the opening 34β does not come into contact with the exhaust gas, and can be maintained at a temperature lower than that of the exhaust gas. Therefore, progress of wear due to sliding between the connecting portion 34α of the connecting structure 34d and the shaft head portion 22a of the support shaft 22 can be suppressed.

(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 4A is an example of a plan view of a connecting structure 34d according to the second embodiment. FIGS. 4B and 4C are other examples of plan views of the connecting structure 34d according to the second embodiment. In addition, the same code|symbol is attached|subjected to the structure similar to each part shown in FIG.2(b), and the description is abbreviate|omitted. The same applies to a third embodiment, which will be described later.

As shown in FIGS. 4A to 4C, the opening 34β can have various shapes. For example, as shown in FIG. 4A, the shape of the opening 34β can be a perfect circle larger than the diameter of the shaft shaft portion 22b. In this case, the gap GP between the shaft shaft portion 22b and the connecting portion 22α in the radial direction of the nozzle plate 34a and the clearance CL provided radially inward of the nozzle plate 34a have the same size. In the case of such a shape, even if the nozzle plate 34a expands, the clearance CL is provided inside the nozzle plate 34a in the radial direction. Avoided. That is, even if the nozzle plate 34a expands radially outward due to the heat of the exhaust gas, it is possible to prevent the nozzle plate 34a from being poorly supported while allowing the expansion.

Further, as shown in FIG. 4B, the shape of the opening 34β can be an oval shape larger than the diameter of the shaft shaft portion 22b. An ellipse may be adopted instead of the oval. In these cases, the gap GP between the shaft shaft portion 22b and the connecting portion 22α in the radial direction of the nozzle plate 34a and the clearance CL provided radially inward of the nozzle plate 34a may be the same, or The size of the clearance CL may be increased. As in the case of the perfect circle, even if the nozzle plate 34a expands radially outward due to the heat of the exhaust gas, it is possible to prevent the nozzle plate 34a from being poorly supported while allowing the expansion.

Furthermore, as shown in FIG. 4(c), the shape of the opening 34β can be a rectangle larger than the diameter of the shaft shaft portion 22b. Squares may be used instead of rectangles. In these cases, as in the case of a perfect circle, even if the nozzle plate 34a expands radially outward due to the heat of the exhaust gas, it is possible to suppress poor support of the nozzle plate 34a while allowing the expansion. can. Incidentally, in the second embodiment, unlike the first embodiment, the connecting portion 34α is not opened. Therefore, when connecting the connecting structure 34d and the support shaft 22 in the second embodiment, for example, the connecting portion 34α is bent toward the radially outer side of the nozzle plate 34a to connect the connecting structure 34d and the support shaft 22. You can connect them.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. 5(a) to 5(c). FIG. 5(a) is a partially enlarged view of the vicinity of the nozzle N according to the third embodiment. FIG. 5(b) is an example of a YY section near the support shaft 22. As shown in FIG. FIG. 5(c) is an example of a ZZ section near the support shaft 22. FIG.

In the third embodiment, a shroud portion 31a of the turbine housing 31 is provided with a nozzle plate (hereinafter referred to as a shroud plate) 34h, which is different from the nozzle plate 34a, as shown in FIG. 5(a). In addition to the nozzle vane 34b, a spacer 34i is arranged between the facing surface of the nozzle plate 34a and the facing surface of the shroud plate 34h. Shroud plate 34h thus supports one side of nozzle vane 34b and one side of spacer 34i.

As shown in FIG. 5B, the nozzle plate 34a has an opening 34β. On the other hand, as shown in FIG. 5(c), the shroud plate 34h has an opening 34γ. Therefore, the openings 34β and 34γ each hold the shaft shaft portion 22b of the support shaft 22 with the gap GP interposed therebetween. Thus, the openings 34β and 34γ are both provided at locations different from the nozzle N.

In the case of the third embodiment, the gap GP between the shaft shaft portion 22b and the shroud plate 34h in the radial direction of the shroud plate 34h and the clearance CL provided radially inward of the shroud plate 34h have the same size. Thus, when the shroud plate 34h has the opening 34γ, even if the shroud plate 34h expands, the clearance CL is provided radially inward of the shroud plate 34h. 34h is avoided until it interferes. That is, even if the shroud plate 34h expands radially outward due to the heat of the exhaust gas, it is possible to prevent the shroud plate 34h from being poorly supported while allowing the expansion.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention described in the scope of claims. Change is possible. For example, the above-described first embodiment and second embodiment may be partially combined as appropriate.

21 bearing housing 22 support shaft 31 turbine housing 32 turbine shaft 34a nozzle plate 34b nozzle vane 34c unison ring 34d connection structure 34h shroud plate 34α connection portion 34β, 34γ opening 34h shroud plate 100 turbocharger CL clearance GP gap

Claims (1)

a ring-shaped nozzle plate supporting one side of a nozzle vane arranged in an exhaust flow path on a first surface through which the exhaust flows ;
a support shaft that does not penetrate the nozzle plate but supports it from a second surface opposite to the first surface ;
a bearing housing that axially supports the support shaft in parallel with the turbine shaft in a staggered manner;
The nozzle plate has an opening that holds the support shaft with a gap in a place other than the flow path, and the opening is located radially inward of the nozzle plate to avoid interference with the support shaft. have clearance to
A supercharger characterized by:

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