JP2011220241A - Turbocharger apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbocharger apparatus, capable of suppressing the displacement and slippage of bearings with respect to a rotating shaft, thereby suppressing the shortening of a life.SOLUTION: The turbocharger apparatus supercharges air fed to an engine by using energy of exhaust gas from the engine. In the apparatus, an expression of L2>L1 is satisfied, where L1 denotes the journal length of the rotating shaft 6, and L2 denotes the total length of each bearing 18, 19 and in the direction of the rotating shaft of a filler piece 20 arranged between the bearings. Furthermore, both bearings 18, 19 and the filler piece 20 are biased to the side of a turbine housing 2 by a fastening force F which is generated when a compressor impeller 10 is connected to the rotating shaft 6.

Description

  The present invention relates to a turbocharger that supercharges air supplied to an engine using the energy of exhaust gas from the engine, and more particularly to a bearing fixing technique that supports rotation of a rotating shaft.

  As means for rotatably supporting the rotating shaft (turbine shaft) of the turbocharger, for example, a ball bearing which is a bearing is used. In the turbocharger, the rotation shaft rotates at a high speed of several tens of thousands to several hundred thousand rotations per minute. Therefore, a spring is provided between the outer rings of a pair of ball bearings to prevent the positional deviation of these ball bearings from the rotation shaft. (Described in Patent Document 1).

JP 2008-298284 A

  However, depending on the fit tolerance (for example, clearance fit) between the ball bearing and the rotating shaft, the ball bearing may be displaced with respect to the rotating shaft only by the spring, and slippage may occur. Therefore, in the turbocharger described in Patent Document 1, it is considered that the rotation mechanism lacks stability and the life is shortened.

  In view of the above, an object of the present invention is to provide a turbocharger capable of suppressing the displacement and slippage of a bearing with respect to a rotating shaft and suppressing a decrease in service life.

  A turbocharger according to the present invention is provided in a turbine housing and is connected to a turbine impeller that is rotated by exhaust gas introduced into the turbine housing, and a rotary shaft that is provided in the compressor housing and is integrated with the turbine impeller. A compressor impeller that rotates together with the turbine impeller to compress air, a pair of bearings that are provided in a bearing housing provided between the turbine housing and the compressor housing, and rotatably support the rotating shaft, A spacer that determines a distance between the pair of bearings by inserting the rotating shaft and mounting the rotating shaft around the shaft, and the journal length of the rotating shaft is L1, and the pair of bearings and the bearing between them The total length of the spacer provided in the direction of the rotation axis When a 2, and L2> L1 becomes relevant, also it has been characterized by both bearings and the spacer by a fastening force when connecting the compressor impeller to the rotating shaft and biased to the turbine housing side.

  According to the present invention, both the bearings and the spacer provided between them are urged toward the turbine housing by the fastening force when the compressor impeller is connected to the rotating shaft. The bearing can be fixed by the fastening force, and the displacement and slippage of the bearing with respect to the rotating shaft can be suppressed. As a result, it is possible to extend the life of the rotating mechanism including the rotating shaft and the bearing that rotatably supports the rotating shaft.

  Further, according to the present invention, the total length L2 in the rotation axis direction of the pair of bearings and the spacer provided between them is made longer than the journal portion length L1 of the rotation shaft (relationship L2> L1). The fastening force can be applied to the bearing and the spacer without pushing the rotating shaft.

FIG. 1 is a cross-sectional view showing the entire turbocharger of this embodiment. FIG. 2 is an enlarged cross-sectional view of the bearing mechanism portion of the turbocharger shown in FIG. FIG. 3 is a cross-sectional view of a bearing mechanism portion in which a bearing and a spacer are incorporated into an oil film damper to form a unit. FIG. 4 is a sectional view showing an exploded state of the bearing mechanism portion. FIG. 5 is a diagram showing the relationship between the journal portion length of the rotating shaft and the total length of the pair of bearings and the spacer provided between them in the rotating shaft direction. FIG. 6A is an enlarged cross-sectional view of the main part showing the abutting position of the bearing on the turbine housing side, and FIG. 6B is an enlarged cross-sectional view of the main part showing the abutting position of the bearing on the compressor housing side.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

[Description of turbocharger configuration]
The turbocharger of this embodiment is a supercharging device that compresses and supercharges air supplied to the engine using the energy of exhaust gas from the engine. The specific configuration of this turbocharger is as follows.

  As shown in FIG. 1, the turbocharger 1 includes a turbine housing 2, a compressor housing 3, and a bearing housing 4 provided between the turbine housing 2 and the compressor housing 3. It is configured.

  The turbine housing 2 is provided with a turbine impeller 5 that is rotated by exhaust gas introduced into the turbine housing 2. The turbine impeller 5 includes a turbine hub 7 integrally formed at one end of a rotating shaft (turbine shaft) 6, and a plurality of turbine blades 8 provided on the outer peripheral surface of the turbine hub 7 at equal intervals.

  The turbine housing 2 is provided with a gas intake (not shown) for taking the exhaust gas G into the housing. Exhaust gas G exhausted from an engine (not shown) is introduced into the gas intake. Further, the turbine housing 2 is provided with a gas discharge port 9 for discharging the exhaust gas G used for rotating the turbine impeller 5 to the outside of the housing. An exhaust gas purification device that purifies the exhaust gas is connected to the gas discharge port 9.

  A turbine scroll passage 10 is provided inside the turbine housing 2 so as to surround the turbine impeller 5. The turbine scroll passage 10 is communicated with a gas intake port and a gas discharge port 9.

  The compressor housing 3 is provided with a compressor impeller 10 that is coupled to the rotary shaft 6 and rotates with the turbine impeller 5 to compress air. The compressor impeller 10 includes a compressor hub 13 that is fixed to the rotary shaft 6 by tightening a nut 12 that is also a fastening means to a screw portion 11 that is a fastening means formed at the other end of the rotary shaft 6, and the compressor It comprises a plurality of compressor blades 14 provided at equal intervals on the outer peripheral surface of the hub 13.

  Further, the compressor housing 3 is provided with an air intake 15 for taking in the air A into the housing. The compressor housing 3 is provided with an air discharge port (not shown) for discharging the air A compressed by the compressor impeller 10. The compressed air discharged from the air discharge port is supplied to, for example, an engine cylinder.

  In addition, an annular diffuser flow path 16 for increasing the pressure of the air A compressed by the compressor impeller 10 is provided inside the compressor housing 3. Further, a compressor scroll passage 17 is provided in the compressor housing 3 so as to surround the compressor impeller 10. The compressor scroll channel 17 is connected to the previous diffuser channel 16.

  In the bearing housing 4, as shown in FIG. 2, a pair of bearings 18 and 19 that rotatably support the rotating shaft 6 and a spacer 20 that determines the distance between the bearings 18 and 19 are incorporated in an oil film damper 21. A bearing mechanism portion (bearing unit) 22 that is a united bearing assembly is provided. FIG. 3 shows the bearing mechanism portion 22 alone, and FIG. 4 shows the exploded bearing mechanism portion 22.

  As shown in FIGS. 3 and 4, the bearings 18 and 19 are formed of ball bearings including an outer ring 23, an inner ring 24, a ball 25, and a retainer 26. The bearings 18 and 19 are press-fitted and attached to bearing mounting portions 27 and 28 formed as fitting recesses on the inner surfaces of both ends of a cylindrical oil film damper 21.

  The outer ring 23 comes into contact with stepped surfaces 31 and 32 which are end surfaces on the opening side of the annular projections 29 and 30 protruding from the inner surface 21a of the oil film damper 21 toward the center. When the outer ring 23 comes into contact with the step surfaces 31 and 32, the mounting positions of the bearings 18 and 19 with respect to the oil film damper 21 are determined. The inner ring 24 comes into contact with the axial end surfaces 20 a and 20 b of the spacer 20 inserted into the oil film damper 21.

  The spacer 20 is made of a steel material such as S45, for example, and functions to determine the distance between the pair of bearings 18 and 19. The spacer 20 is formed as a cylindrical body that is inserted around the journal portion 6A by inserting the journal portion 6A of the rotary shaft 6 into the center hole 33 with a slight gap. Further, an annular groove 35 is formed on the inner surface 34 of the spacer 20 so as to have a step that is one step lower than the inner surface 34 except for both ends in the axial direction. The annular groove 35 is configured to be in non-contact with the journal portion 6A, and functions to facilitate insertion into the spacer 20 of the journal portion 6A.

Note that the journal portion 6A of the rotating shaft 6 defined here indicates a corresponding portion of the bearing 18 on the turbine housing side, the bearing 19 on the compressor housing side, and the spacer 20. Since both the bearings 18 and 19 on the turbine housing side and the compressor housing side and the spacer 20 provided therebetween function as a bearing of the rotary shaft 6 as a whole, both the bearings 18 and 19 and the spacer 20 Corresponds to the journal portion 6A of the rotary shaft 6.

  The oil film damper 21 is formed as a cylindrical body in which the spacer 20 is housed and arranged in the center of the interior, and bearings 18 and 19 are attached to both ends of the interior. The oil film damper 21 includes an oil supply annular groove 37 for supplying oil from an oil supply passage 36 formed in the bearing housing 4 to the bearings 18 and 19, and the oil supply annular groove 37 through the bearing 18. , 19 is formed with an oil discharge passage 38 for supplying oil.

  The oil supply annular groove 37 is formed between two annular protrusions 39, 39 protruding from the outer peripheral surface 21b. The oil supply annular groove 37 is provided at two locations for supplying oil to the bearings 18 and 19. The oil discharge passage 38 is formed in the annular protrusions 29 and 30 so that the inlet opens to the oil supply annular groove 37 and the outlet faces between the outer ring 23 and the inner ring 24 of the bearings 18 and 19. .

  The oil film damper 21 is formed with an oil discharge hole 40 for discharging excess oil supplied to the bearings 18 and 19 from a discharge hole 50 formed in the bearing housing 4 to the outside.

  The spacer 20 is sandwiched between the two bearings 18 and 19 that are press-fitted into both ends of the oil film damper 21 before being attached to the journal portion 6A. However, since the spacer 20 is not positioned in the radial direction, the spacer 20 moves in the radial direction. Misalignment may occur. Therefore, the temporary assembly rod 41 (shown by a two-dot chain line in FIG. 3) is inserted into the center hole 33 of the spacer 20 and is mounted in the radial direction of the spacer 20 until it is attached to the rotary shaft 6. Prevent misalignment. The temporary assembly rod 41 is removed when the journal portion 6A of the rotating shaft 6 is inserted into the spacer 20.

  The bearing housing 4 is provided with a cooling water passage 42 for absorbing and cooling heat generated from the bearings 18 and 19 that support the rotating shaft 6 that rotates at a high speed and heat of exhaust gas introduced into the turbine housing 2. ing. The cooling water channel 42 is formed along the circumferential direction, and circulates the cooling water supplied from the cooling water supply source. The cooling water passage 42 is formed at a position near the turbine impeller 5 and also at a position near the compressor impeller 10. 1 and 2, the cooling water passage 42 formed at a position near the compressor impeller 10 is not shown.

  As described above, the bearing mechanism portion 22 in which the pair of bearings 18 and 19 and the spacer 20 are assembled to the oil film damper 21 as a unit is assembled to the bearing housing 4. The rotating shaft 6 integrated with the turbine impeller 5 is assembled to the bearing mechanism portion 22 assembled to the bearing housing 4. Thereafter, the compressor impeller 10 is assembled to the rotating shaft 6. In order to assemble the rotating shaft 6 to the bearing mechanism portion 22, the journal portion 6 </ b> A of the rotating shaft 6 is inserted into the inner ring 24 of one bearing 18 and then inserted into the inner ring 24 of the other bearing 19 through the spacer 20. Actually, with the rotary shaft 6 standing vertically and the turbine impeller 5 being fixed downward, the rotary shaft 6 is mounted on the bearings 18 and 19 and the spacer 20 of the bearing mechanism portion 22 incorporated in the bearing housing 4. To insert.

  Of the pair of bearings 18, 19, the bearing 18 on the turbine impeller 5 side has a hub end surface 7a in which the inner ring 24 is a boundary portion between the turbine hub 7 and the journal portion 6A, as shown in FIGS. To come into contact. When the outer diameter H of the portion where the hub end surface 7a is provided has a size corresponding to the height position corresponding to the inner ring 24 and the outer ring 23, the outlet of the oil OIL flowing out between the outer ring 23 and the inner ring 24 is blocked. It becomes difficult to discharge the oil OIL. Therefore, as shown in FIG. 6A, it is preferable that the outer diameter H1 of the portion where the hub end surface 7a with which the inner ring 24 is in contact is provided is a size within the outer diameter dimension H2 of the inner ring 24.

  On the other hand, in the bearing 19 on the compressor impeller 10 side, as shown in FIGS. 5 and 6B, the inner ring 24 comes into contact with the inner end face 43a of the oil draining member 43 provided between the compressor hub 13 and the journal portion 6A. It is like that. For the same reason, the outer diameter H3 of the portion where the inner end face 43a of the oil draining member 43 in contact with the inner ring 24 is preferably set to a size within the outer diameter dimension H2 of the inner ring 24.

  At this time, the length of the journal portion 6A of the rotating shaft 6 (hereinafter referred to as the journal portion length) is L1, and the total length in the rotating shaft direction of the pair of bearings 18 and 19 and the spacer 20 provided therebetween. When L2 is L2, the relationship is L2> L1. That is, the journal length L1 of the rotating shaft 6 which is the length of the portion corresponding to the pair of bearings 18 and 19 is the axial length of the pair of bearings 18 and 19 and the spacer 20 disposed between them. The total length L2 is shorter than the total length L2. In other words, the total length L2 is longer than the journal portion length L1. For this reason, a gap S is formed between the end surface 44 of the journal portion 6 </ b> A on the compressor impeller side and the inner end surface 43 a of the oil draining member 43. As a result, the end face 44 of the journal portion 6A is not pushed by the oil draining member 43.

  A fastening force F generated by fastening the compressor impeller 10 to the screw portion 11 formed at the tip of the rotating shaft 6 with the nut 12 acts on the bearings 18 and 19 and the spacer 20. The fastening force F is transmitted to the oil draining member 43 through the compressor impeller 10 by tightening the nut 12, and the compressor impeller side bearing 19 (directly the inner ring 24 directly contacting the oil draining member 43). ), And further via the spacer 20 to the turbine impeller bearing 18 (directly the inner ring 24). Due to the fastening force F applied along the axial direction of the rotating shaft 6, the bearings 18, 19 and the spacer 20 are positioned without rattling in the rotating shaft direction. Since the spacer 20 is attached to the journal portion 6A, the spacer 20 rotates together with the rotary shaft 6.

[Description of turbocharger operation]
In the turbocharger 1 configured as described above, when the exhaust gas G taken into the turbine housing 2 from the gas inlet is supplied to the turbine impeller 5 side via the turbine scroll flow path 10, the exhaust gas G The turbine impeller 5 is rotated by the energy of. The compressor impeller 10 connected to the rotating shaft 6 of the turbine impeller 5 is rotationally driven by the rotation of the turbine impeller 5. When the compressor impeller 10 rotates, the air A taken in from the air intake port 15 is compressed and supercharged from the air discharge port into the engine cylinder via the diffuser flow channel 16 and the compressor scroll flow channel 17.

[Effect of the embodiment]
According to the turbocharger 1 of the present embodiment, the bearings 18 and 19 and the spacer 20 provided between them are attached to the turbine housing 2 side by the fastening force F when the compressor impeller 10 is connected to the rotary shaft 6. Therefore, the bearings 18 and 19 can be fixed with a large fastening force F, unlike the spring force, and the displacement and slippage of the bearings 18 and 19 with respect to the rotating shaft 6 can be suppressed. As a result, it is possible to extend the life of the rotating mechanism including the rotating shaft 6 and the bearings 18 and 19 that rotatably support the rotating shaft 6.

  Further, according to the turbocharger 1 of the present embodiment, the total length L2 of the pair of bearings 18 and 19 and the spacer 20 provided therebetween in the direction of the rotation shaft 6 is greater than the journal portion length L1 of the rotation shaft 6. (L2> L1), the fastening force F can be applied to the bearings 18 and 19 and the spacer 20 without pushing the rotating shaft 6.

  Further, according to the turbocharger 1 of the present embodiment, since the spacer 20 is brought into contact with the inner rings 24 of the pair of bearings 18 and 19, the inner ring 24 that easily slips between the journal portion 6 </ b> A of the rotating shaft 6. The position of can be fixed.

  Further, according to the turbocharger 1 of the present embodiment, the journal portion 6A of the rotating shaft 6 is inserted into the spacer 20 and rotated together with the rotating shaft 6. Therefore, the diameter of the journal portion 6A is substantially reduced by the spacer 20. Accordingly, the rigidity of the rotary shaft 6 itself can be increased.

  Further, according to the turbocharger 1 of the present embodiment, since the annular groove 35 that forms a gap with the journal portion 6A is formed in a part of the inner peripheral surface 34 of the spacer 20, the rotating shaft 6 The operation when inserting the journal portion 6A into the spacer 20 can be facilitated.

  Further, according to the turbocharger 1 of the present embodiment, the bearing mechanism unit 22 is unitized by incorporating the pair of bearings 18 and 19 and the spacer 20 that determines the distance between the bearings 18 and 19 into the oil film damper 21. As a result, the assembly work of the turbocharger can be greatly simplified. When not unitized, one bearing 18 is attached to the rotary shaft 6 integrated with the turbine impeller 5, then the spacer 20 is attached, the other bearing 19 is attached, and finally the oil draining member 43 is interposed. The operation | work which attaches the compressor impeller 10 is needed. However, according to the present embodiment, the assembly operation can be completed only by attaching the compressor impeller 10 via the oil draining member 43 after assembling the bearing mechanism portion 22 to the rotary shaft 6.

  Further, according to the turbocharger 1 of the present embodiment, since the bearings 18 and 19 and the spacer 20 are preliminarily incorporated in the oil film damper 21 as the bearing mechanism section 22, they are transported as the bearing mechanism section 22 instead of for each component. The handling of these parts can be greatly improved. In the present embodiment, since the bearings 18 and 19 and the spacer 20 are incorporated in the oil film damper 21 in advance, vibrations of the bearings 18 and 19 and the spacer 20 accompanying the rotation of the rotating shaft 6 can be suppressed. it can.

  Further, according to the turbocharger 1 of the present embodiment, the bearings 18 and 19 are press-fitted into the bearing mounting portions 27 and 28 formed on the oil film damper 21 in advance, so that the oil that has been used so far is used. Curing treatment on the inner surface of the film damper can be eliminated.

  Moreover, according to the turbocharger 1 of this embodiment, since the journal part 6A of the rotating shaft 6 is inserted into the spacer 20 and integrated, the induction hardening process of the rotating shaft 6 that has been performed so far is performed. Can be eliminated. Since the surface of the journal portion 6A is covered with the spacer 20, the rigidity is increased, so that it is not necessary to perform quenching.

  The specific embodiment to which the present invention is applied has been described above, but the present invention is not limited to the above-described embodiment.

  In the above-described embodiment, the journal portion 6A of the rotating shaft 6 is inserted with a slight gap with respect to the center hole 33 of the spacer 20, but the journal portion 6A is press-fitted into the center hole 33 with a low load. May be. In this case, since the annular groove 35 is formed in the spacer 20, press-fit workability of the journal portion 6 </ b> A to the spacer 20 is facilitated.

  In the above-described embodiment, the inner ring 24 of the bearing 18 on the turbine housing side is brought into contact with the hub end surface 7 a of the turbine hub 7, and the inner ring 24 of the bearing 19 on the compressor housing side is brought into contact with the inner end surface 43 a of the oil draining member 43. Structure. On the other hand, for example, when a spacer is interposed between the turbine hub 7 and the inner ring 24, the inner ring 24 comes into contact with the end face of the spacer. Similarly, when a spacer that does not have a function of oil draining is disposed instead of the oil draining member 43, the inner ring 24 comes into contact with the end face of the spacer.

  The present invention can be used for a turbocharger that supercharges air supplied to an engine using energy of exhaust gas from the engine.

DESCRIPTION OF SYMBOLS 1 ... Turbocharger 2 ... Turbine housing 3 ... Compressor housing 4 ... Bearing housing 5 ... Turbine impeller 6 ... Rotating shaft (turbine shaft)
6A ... Journal part 7 ... Turbine hub 8 ... Turbine blade 10 ... Compressor impeller 12 ... Nut 13 ... Compressor hub 14 ... Compressor blade 18, 19 ... Bearing 20 ... Spacer 21 ... Oil film damper 22 ... Bearing mechanism part 23 ... Outer ring 24 ... Inner ring 43 ... Oil draining member

Claims (4)

A turbine impeller provided in the turbine housing and rotated by exhaust gas introduced into the turbine housing;
A compressor impeller provided in a compressor housing, connected to a rotating shaft integrated with the turbine impeller, and rotated with the turbine impeller to compress air;
A pair of bearings provided in a bearing housing provided between the turbine housing and the compressor housing and rotatably supporting the rotating shaft;
A spacer for determining the distance between the pair of bearings by inserting the rotating shaft and mounting it around the shaft;
When the length of the journal portion of the rotating shaft is L1, and the total length in the rotating shaft direction of the pair of bearings and the spacer provided between them is L2, the relationship is L2> L1, and the rotation A turbocharger characterized in that both bearings and spacers are urged toward the turbine housing by a fastening force when the compressor impeller is coupled to a shaft. The turbocharger according to claim 1, wherein
The said spacer was made to contact the inner ring | wheel of a pair of said bearing, respectively. The turbocharger characterized by the above-mentioned. A turbocharger according to claim 1 or claim 2,
The said spacer is inserted in the said rotating shaft, and rotates with this rotating shaft. The turbocharger characterized by the above-mentioned. A turbocharger according to any one of claims 1 to 3,
A turbocharger, wherein a groove is formed on a part of an inner peripheral surface of the spacer so as to form a gap with the rotation shaft.

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