1. Field of the Invention
The present invention relates to a method for manufacturing a variable capacity exhaust gas turbine in an exhaust gas turbocharger used for the internal combustion engine of a comparably small or medium size; whereby, the exhaust gas emitted from the engine (internal combustion) streams through a scroll passage for feeding the exhaust gas from an exhaust gas inlet to a turbine rotor, the cross-section area of the scroll passage comprising an outer scroll passage and an inner scroll passage is gradually reduced along the gas stream direction; thereby, the scroll passage is partitioned into the outer scroll passage that is placed at an outer side in the direction of the radius of the turbine rotor and the inner scroll passage that is placed at an inner side in the direction of the radius of the turbine rotor, wherein a plurality of insert vanes is provided between the outer scroll passage and the inner scroll passage so that the exhaust gas streams into the inner scroll passage not only directly from the exhaust gas inlet but also via the outer scroll passage; and, a cover that demarcates the scroll passage is provided with the insert vanes that protrude from the body surface of the cover toward the scroll passage, the insert vanes being arranged in a row along a boundary wall between the outer scroll passage and the inner scroll passage.
2. Background Art
The variable capacity exhaust gas turbine as described above houses a turbine rotor 10 driven by the exhaust gas, in the middle part (around the rotation axis 100a) of a turbine housing of the gas turbine.
The turbine housing 01 comprises an exhaust gas inlet 20 and an exhaust gas outlet 20a; the turbine housing 01 further comprises a scroll passage through which the exhaust gas flows from an exhaust gas inlet 20 toward a turbine rotor 10 that is positioned at an inner (central) part of the housing, the cross-section of the scroll passage gradually reducing along the gas stream direction.
The scroll passage is divided into two parts; namely, the scroll passage comprises an inner scroll passage 2 and an outer scroll passage 1; between the inner scroll passage 2 and the outer scroll passage 1, a plurality of insert vanes 6a are installed in a row as the vanes are arranged along a boundary (partition) wall 2a of the scroll passage 12, in a hoop direction (a spiral direction) around the center axis of the turbine; the insert vanes 6a as well as the boundary wall play the role in partitioning the scroll passage. Further, an exhaust gas passage 6b is formed between each vane and the adjacent vane thereof.
Moreover, the multiple insert vanes 6a are provided on a cover 6 as shown in
Further, according to Patent Reference 1 as shown in
Further, as shown in
Further, a control valve 4 is provided so as to control the exhaust gas flow rates into the inner scroll passage 2 as well as into the outer scroll passage 1, in a manner that the control valve 4 comes in contact with a periphery wall 4a as well as leaves the periphery wall 4a, the periphery wall 4a being formed in the turbine housing 01.
In other words, the outer scroll passage 1 is closed during the engine low-speed operation so that the control valve 4 comes into contact with the periphery wall 4a and closes (the inlet of) the outer scroll passage 1; thus, the engine exhaust gas flows only into the inner scroll passage 2 along the direction of the curved arrow U2 as shown in
On the other hand, the outer scroll passage 1 is opened during the engine high-speed operation so that the control valve 4 leaves the periphery wall 4a and opens (the inlet of) the outer scroll passage 1; thus, the engine exhaust gas flows not only into the inner scroll passage 2 along the direction of the curved arrow U2 but also into the outer scroll passage 1 along the direction of the curved arrow U1 as shown in
Thus, the exhaust gas flow rate can be changed from the engine low-speed speed operation to the engine high-speed operation, and vice versa, by controlling the control valve 4.
PATENT REFERENCE 1: JP3956884
In manufacturing the variable capacity exhaust gas turbine (as a finished product namely a complete product) that is shown in
(1) As shown in
In fear of the contact (interference) between the mutually facing members in being assembled as well as in consideration of the manufacturing tolerance, a considerably large clearance 19a (a dimension S1) is provided between the tongue 5 that is formed in the turbine housing 01 and a body surface 6p that is the surface of the main body of the cover 6, as the body surface 6p is a raw work-piece surface or both of the body surface 6p and the tongue 5 are raw work-piece surfaces.
However, the smaller the clearance, the better the turbine efficiency, as for the clearance 19a between the tongue 5 and the body surface 6p; nevertheless, a considerably large clearance 19a has to be practically provided; thus, a problem arises that the exhaust gas leakage increases through the clearance 19a and the turbine efficiency decreases.
(2) In addition, as shown in
In view of the subjects to be overcome as described above, the present invention aims at providing a manufacturing method for manufacturing a variable capacity exhaust gas turbine, the gas turbine comprising a part that is made by row material (work-piece) forming process such as metal casting and is machined to form a completed part as a finished product, whereby the clearance around the tongue can be limited to a minimal dimension level, the tongue being provided so that the exhaust gas smoothly flows into the inner scroll passage; and, the present invention aims at providing high accuracy as to the installation arrangement of the cover, the accuracy being related to the installation (fitting arrangement) of the cover that is fitted in the neighborhood of the circular periphery part of the cover.
In order to overcome the problems in the conventional technology as described above, the present invention discloses a manufacturing method for manufacturing a variable capacity exhaust gas turbine, the gas turbine comprising:
a turbine shaft supported by a bearing housing;
a turbine rotor that is fixed to an end of the turbine shaft and rotationally driven by exhaust gas;
an exhaust gas inlet through which the exhaust gas is supplied;
an exhaust gas outlet through which the exhaust gas is discharged; and
a turbine housing comprising:
a scroll passage between said exhaust gas inlet and said turbine rotor, the cross-section area of the scroll passage gradually reduces along the direction of the exhaust gas stream, the scroll passage is provided with an inner scroll passage and an outer scroll passage into which the scroll passage is divided along a hoop direction around the turbine rotor,
a plurality of insert vanes being provided in a row along the boundary between the inner scroll passage and the outer scroll passage, the row of insert vanes being configured so that the exhaust gas flow directly into the inner scroll passage and the exhaust gas flow into the inner scroll passage via the outer scroll passage are controlled,
and a control valve that is arranged at an exhaust gas inlet side as to the outer scroll passage so as to control the exhaust gas flow rate into the inner scroll passage as well as into the outer scroll passage, and an opening end face that faces the bearing housing;
the gas turbine further comprising:
a cover that is arranged at the opening end face of the turbine housing so as to demarcate the inner scroll passage and the outer scroll passage, the insert vanes being provide so as to protrude from the body of the cover toward the side of the exhaust gas passage;
wherein, a thickness-reducing plate part is extended so as to form an integrated part together with the cover, thereby the plate thickness is reduced from the outer side to the inner side toward the rotation axis of the turbine rotor, the cover and the thickness-reducing plate part being arranged in a gap between the bearing housing and the turbine rotor, along a plane vertical to the rotation axis of the turbine rotor;
the cover and the thickness-reducing plate part are formed as an integrated member by means of any one of casting, injection molding, or cold forging;
the raw work-piece surface of the cover is provided with a protrusion part in the raw work-piece manufacturing stage so that the protrusion part protrudes from the raw work-piece surface of the cover, the protrusion part being arranged in response to the arrangement of a tongue that is formed in the neighborhood of the exhaust gas inlet of the inner scroll passage in the turbine housing as a part thereof;
the integrated member as to the cover and the thickness-reducing plate part is assembled into the gas turbine after the protrusion part is machined so that an allowable clearance is formed between the tongue and the protrusion part.
A preferable embodiment of the above-disclosure is the manufacturing method for manufacturing a variable capacity exhaust gas turbine, whereby
the integrated member as to the cover and the thickness-reducing plate part comprises a connection part between the cover and the thickness-reducing plate part, the connection part is provided with a circle ringed protrusion toward the bearing housing, the circle ringed protrusion being formed so that the circle ringed protrusion and the integrated member as to the cover and the thickness-reducing plate part form an integrated body in and from the stage of raw work-piece forming;
the inner periphery of the circle ringed protrusion is machined in a machining process following to the raw work-piece forming process, so that an outer circle periphery step-surface of the bearing housing 11 is fitted into the inner periphery of the circle ringed protrusion in the stage of the assembling process of the gas turbine, in order that the integrated member as to the cover, the thickness-reducing plate part and the connection part is supported by from the bearing housing.
Another preferable embodiment following the above is the manufacturing method for manufacturing a variable capacity exhaust gas turbine, whereby
an outer periphery surface that is an outer circumferential circle surface of the cover is machined;
a convex part that is formed around the outer periphery of the cover, in an adjacent neighborhood of the outer periphery surface, thereby convex part sandwiched between the bearing housing and the turbine housing so that the bearing housing and the turbine housing support the cover;
the thickness-reducing plate part that is extended from the cover in a gap between the turbine housing and the bearing housing toward the rotation axis of the turbine rotor is placed under a free condition without deformation constraint, so that the thermal expansion of the thickness-reducing plate becomes allowable.
According to the disclosure of the present invention, in manufacturing processes including a raw work-piece forming process by use of any one of casting, injection molding or cold forging, as well as, finishing (machining) process to produce a completed assembling part,
the exhaust gas turbine is provided with a thickness-reducing plate part that is extended so as to form an integrated part together with the cover, thereby the plate thickness reduces from the outer side to the inner side toward the rotation axis of the turbine rotor, the cover and the thickness-reducing plate part being arranged in a gap between the bearing housing and the turbine rotor, along a plane vertical to the rotation axis of the turbine rotor;
the cover and the thickness-reducing plate part are formed as an integrated member through a raw work-piece forming process;
the raw work-piece surface of the cover is provided with a protrusion part in the raw work-piece manufacturing stage so that the protrusion part protrudes from the raw work-piece surface of the cover, the protrusion part being arranged in response to the arrangement of the tongue that is formed in the exhaust gas passage of the turbine housing;
the integrated member as to the cover and the thickness-reducing plate part is assembled into the gas turbine after the protrusion part is machined so that an allowable clearance is formed between the tongue and the protrusion part.
Thus, in response to the tongue formed in the turbine housing, the raw work-piece surface of the cover is provided with a protrusion part in the raw work-piece manufacturing stage so that the protrusion part protrudes from the raw work-piece surface; the integrated member as to the cover and the thickness-reducing plate part is assembled into the gas turbine after the protrusion part is machined in the following machining stage so that an allowable clearance is formed between the tongue and the protrusion part. In conclusion, the above-described clearance can be controllably achieved by machining.
Accordingly, a machining process obtains the clearance between the tongue and the cover body surface; therefore, the clearance can be constrained to a minimal level. As a result, the exhaust gas leakage through the clearance can be reduced, and the efficiency of the exhaust gas turbine can be enhanced.
Further, only a part of the raw work-piece surface of the cover is protruded so as to form the protrusion part that is only the machined part; thus, the manufacturing and the (assemble) structure become simple and cost-effective.
According to a preferable embodiment of the present invention,
the integrated member as to the cover and the thickness-reducing plate part comprises a connection part between the cover and the thickness-reducing plate part, the connection part is provided with a circle ringed protrusion toward the bearing housing, the circle ringed protrusion being formed so that the circle ringed protrusion and the integrated member as to the cover and the thickness-reducing plate part form an integrated body in and from the stage of raw work-piece forming;
the inner periphery of the circle ringed protrusion is machined in a machining process following to the raw work-piece forming process, so that an outer (circle) periphery step-surface of the bearing housing is fitted into the inner periphery of the circle ringed protrusion in the stage of the assembling process of the gas turbine, in order that the integrated member as to the cover, the thickness-reducing plate part and the connection part is (able to be) supported by from the bearing housing.
On the other hand, according to the conventional approach as depicted in
According to another preferable embodiment of the present invention,
an outer periphery surface that is an outer circumferential circle surface of the cover is machined;
a convex part that is formed around the outer periphery of the cover, in an adjacent neighborhood of the outer periphery surface, thereby convex part sandwiched between the bearing housing and the turbine housing so that the bearing housing and the turbine housing support the cover;
the thickness-reducing plate part that is extended from the cover in a gap between the turbine housing and the bearing housing toward the rotation axis of the turbine rotor is placed under a free condition without deformation constraint, so that the thermal expansion of the thickness-reducing plate becomes allowable.
In this way, the outer periphery surface that is an outer circumferential circle surface of the cover is machined in a machining process after the raw work-piece forming process.
Thus, with a configuration as described above, the thermal expansion of the thickness-reducing plate part (as a heat insulation plate) becomes permissible so that thermal stress due to thermal deformation constraint is prevented. Consequently, the thermal expansion of the thickness-reducing plate part (a radiation-heat insulation plate) can be prevented from being broken.
Hereafter, the present invention will be described in detail with reference to the embodiments shown in the figures. However, the dimensions, materials, shape, the relative placement and so on of a component described in these embodiments shall not be construed as limiting the scope of the invention thereto, unless especially specific mention is made.
As shown in
Further, the compressor housing 13 is connected to the turbine housing 01 via a bearing housing 11.
The scroll passage 12 is divided into two passages, an inner scroll passage 2 and an outer scroll passage 1 in a radial direction of the turbine rotor. In addition, the numeral 4 denotes a control valve that is explained later.
The basic configuration of the above is the same as the conventional configuration of the conventional art described in
The present invention is peculiarly related to a raw work-piece forming and machining thereof in connection with an insert member 60 that comprises a cover 6 as well as a thickness-reducing plate part 62.
As shown in
In the present embodiment, the raw work-piece as to the insert member 60 comprising the cover 6 and the thickness-reducing plate part 62 is to be formed by means of precision casting; as a matter of course, the insert member 60 may be formed by means of any one of lost-wax process, metal injection molding, cold forging or the like.
The shape and the configurations as to the insert member 60 are depicted in
As shown in
Further, the insert vanes 6a form a part of the cover 6 so that the vanes protrude toward the exhaust side, substantially along the direction parallel to the rotation axis; the vanes are configured so as to control the exhaust gas stream. In addition, between each of the insert vanes 6a, an exhaust gas passage 6b is formed; a row of exhaust gas passages 6b is formed in a spiral direction around the rotation axis, as is the case with the raw of insert vanes 6a.
As shown in
The thickness-reducing plate part 62 is provided so as to face the turbine rotor 10, and is used to shield the heat flux from the turbine rotor.
As described thus far, the insert member 60 that comprises the cover 6 and the thickness-reducing plate part 62 and is made by precision casting in the stage of a raw work-piece forming; surface machining is performed as to the inner periphery surface (Diameter D1) of the ringed protrusion part 7 in the cover 6 in a machining process.
Further, an outer periphery step-surface 11a of the bearing housing 11 is fitted into the machined surface 7e of the inner periphery of the circle ringed protrusion 7 so that the bearing housing 11 supports the insert member 60. In other words, by adding surface machining on the inner periphery surface (Diameter D1) of the ringed protrusion 7 of the cover 6, a surface with high accuracy (dimension accuracy) is obtained; thus, the fitting accuracy as to the inner periphery surface (Diameter D1) and the outer periphery step-surface 11a of the bearing housing 11 is enhanced (see
In the manner as described, surface machining is performed on both the inner periphery surface (Diameter D1) of the ringed protrusion 7 and the outer periphery step-surface 11a of the bearing housing 11, thereby the ringed protrusion part 7 being arranged between the inner side (the small radius side) of the cover 6 and the thickness-reducing plate part 62; thus, both the surfaces (contact surfaces as to the ringed protrusion part 7 and the bearing housing 11) are fitted each other with high accuracy and without misalignment.
On the other hand, according to the conventional approach as depicted in
In the next place, as shown in
Further, on a side surface of the cover 6 opposite to the side surface where the insert vanes are provided to, a plurality of ribs 69 is provided in radial directions. It is noted that the thickness-reducing plate part 62 is not provided with ribs, and is formed as a thin disk so as to play the role of a heat insulation plate.
According to the configuration as described above, the outer periphery surface 6u that is an outer circumferential (circle) surface of the cover 6 is machined when (or after) the insert member is manufactured as a raw work-piece member; the area in the neighborhood of the outer periphery surface 6u is sandwiched between the bearing housing 11 and the turbine housing 01 that support the cover 6; the thickness-reducing plate part (a heat insulation plate) 62 that is exposed to a high temperature condition is extended, in a gap between the turbine housing and the bearing housing, toward the rotation axis, without an inner side (the rotation axis side) constraint condition (under a free condition without deformation constraint). Thus, the thermal expansion of the thickness-reducing plate part (a heat insulation plate) 62 becomes permissible so that thermal stress due to thermal deformation constraint is prevented. Consequently, the thickness-reducing plate part (a heat insulation plate) 62 can be prevented from being broken by the thermal stress.
Next, as shown in
Hence, in the embodiment like this, as shown in
The protrusion part 19s is machined so that a clearance S is formed between the tongue 5 and the protrusion part 19s, before the cover 6 is installed into the exhaust gas turbine.
According to the configuration as described, as shown in
Accordingly, the optimally minimum limit dimension as to the clearance S between the finished surface 19 and the tongue 5 can be adopted, due to the machining process. Thus, the gas leakage through the clearance S can be reduced, and the efficiency of the gas turbine can be enhanced.
Further, as for the cover 6, only a part of the raw work-piece surface is protruded so as to form the protrusion part 19s which is only the machined part. Thus, the manufacturing and the assemble structure become simple and cost-effective.
In the next place, according to the embodiment of the present invention, an explanation is now given in relation to the assembling of the described structural members.
As shown in
In addition, as shown in
In addition, as is the case with the conventional approach of
In other words, the control valve 4 comes into contact with the periphery wall 4a during the engine low-speed operation so that the outer scroll passage 1 is closed; thus, the engine exhaust gas flows only into the inner scroll passage 2 along the direction of a curved arrow U2 (cf.
Thus, the exhaust gas flow rate can be changed from the engine low-speed speed operation to the engine high-speed operation, and vice versa, by controlling the control valve 4.
The present invention can provide a manufacturing method for manufacturing a variable capacity exhaust gas turbine, the gas turbine comprising a configuration member that is manufactured through a process of raw work-piece forming such as casting and a subsequent process of finished machining, whereby the clearance around the tongue for making the exhaust gas smoothly stream can be formed so as to be restrained to a minimal level, and the cover can be in stalled in the exhaust gas turbine so as to be fitted in the neighborhood of the ring protrusion part of the cover, with higher accuracy.
Number | Date | Country | Kind |
---|---|---|---|
2008-220363 | Aug 2008 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2009/064400 | 8/17/2009 | WO | 00 | 7/12/2010 |