JP2009174358A - Supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase a pressure ratio by reducing stress due to centrifugal force when a compressor impeller revolves at high speed, and enabling high speed revolution of the compressor impeller. <P>SOLUTION: In this supercharger 1, an impeller 8 is provided on a distal end of a rotary shaft 2 extending from a turbine 7, the rotary shaft is rotatably supported by a bearing housing 5, the turbine is stored in a turbine housing 12, and the impeller is stored in a compressor housing 13. A fitting shaft part 21 and a screw part 22 are formed at the distal end of the rotary shaft. The fitting shaft part is fitted in the impeller, and the screw part is screwed to the impeller to connect the rotary shaft and the impeller. A screw hole in which the screw part is screwed is bored at the impeller in such a manner that the deepest position of the screw hole does not reach the maximum diameter position of the impeller. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a supercharger provided for increasing the output of an internal combustion engine and improving combustion efficiency.

  In order to increase the output of the internal combustion engine and improve the combustion efficiency, a supercharger is provided. The supercharger is a turbine driven using the energy of exhaust gas, and a compressed air provided coaxially with the turbine. And a compressor for supplying air to the internal combustion engine.

  In order to further increase the output of the internal combustion engine and improve the combustion efficiency, a higher pressure ratio is required for the supercharger, but there is a limit to the pressure ratio obtained from the structure of the supercharger.

  A conventional supercharger will be described with reference to FIG.

  The supercharger 1 includes a turbine 3 and a compressor 4 that share a rotating shaft 2.

  The rotary shaft 2 is rotatably supported by a bearing housing 5 via a bearing 6, a turbine impeller 7 is provided at one end of the rotary shaft 2, and a compressor impeller 8 made of, for example, aluminum alloy is provided at the other end. Is provided.

  The rotating shaft 2 and the turbine impeller 7 are integral, and the other end of the rotating shaft 2 passes through the compressor impeller 8. A screw portion 9 is formed at a protruding portion of the other end of the rotary shaft 2, and a nut 11 is screwed onto the screw portion 9, and the nut 11 is tightened, whereby the compressor impeller 8 is moved to the rotary shaft. 2 is fixed.

  The turbine impeller 7 is accommodated in a turbine housing 12 attached to the bearing housing 5, and the compressor impeller 8 is accommodated in a compressor housing 13 attached to the bearing housing 5.

  The turbine 3 is configured by the turbine impeller 7, the turbine housing 12, and the like, and the compressor 4 is configured by the compressor impeller 8, the compressor housing 13, and the like.

  The turbine housing 12 has an exhaust gas inlet 14 and an exhaust gas outlet 15. Exhaust gas from an internal combustion engine flows into the exhaust gas inlet 14, and the exhaust gas outlet 15 supplies the exhaust gas by exhaust energy. The exhaust gas after rotating the turbine impeller 7 is exhausted.

  The compressor housing 13 has a suction port 16 and a discharge port 17, and the air sucked from the suction port 16 when the compressor wheel 8 is rotated by the turbine wheel 7 via the rotary shaft 2. And the compressed air is supplied to the internal combustion engine from the discharge port 17.

  By increasing the pressure ratio of the air supplied from the compressor 4, the output of the internal combustion engine can be increased and the combustion efficiency can be improved. In order to increase the pressure ratio, it is necessary to rotate the compressor wheel 8 at a higher speed.

  However, when the compressor wheel 8 rotates at a high speed, a large centrifugal force acts on the compressor wheel 8. In particular, a large stress caused by centrifugal force is generated at a position corresponding to the maximum diameter portion position M of the compressor wheel 8 in a hole through which the rotary shaft 2 of the compressor wheel 8 passes.

  FIG. 7 shows the distribution of the ratio with the maximum stress generated in the disk portion 8a of the compressor wheel 8 when the compressor wheel 8 is rotated, and the hole 8c through which the rotary shaft 2 passes. It can be seen that the stress corresponding to the maximum diameter portion 8d of the compressor impeller 8 is the maximum.

  For this reason, the rotational speed of the compressor wheel 8 is constrained by the stress generated in the maximum diameter portion 8d being equal to or less than the allowable value. When it exceeded, there existed a possibility that the said compressor impeller 8 might be damaged.

JP 2005-30382 A

JP-A-2005-330816

  In view of such circumstances, the present invention reduces stress due to centrifugal force when the compressor wheel is rotated at high speed, enables high speed rotation of the compressor wheel, and increases the pressure ratio.

  In the present invention, a compressor wheel is provided at the tip of a rotating shaft extending from a turbine wheel, the rotating shaft is rotatably supported by a bearing housing, the turbine wheel is accommodated in a turbine housing, and the compressor blade The vehicle is a supercharger housed in a compressor housing, and a fitting shaft portion and a screw portion are formed at a tip portion of the rotating shaft, and the fitting shaft portion is fitted to the compressor impeller and the screw. The screw hole is connected to the compressor wheel and the rotary shaft and the compressor wheel are connected, and the screw hole screwed into the screw part has the deepest position of the screw hole at the maximum diameter position of the compressor wheel. This is related to the supercharger drilled in the compressor impeller so as not to reach.

  Further, according to the present invention, the fitting shaft portion has a small diameter with respect to the rotating shaft, a thrust collar and a thrust bearing are provided between the rotating shaft and the compressor impeller, and the thrust load is transmitted through the thrust bearing. The turbocharger is configured to be supported by a bearing housing and to be supplied with lubricating oil between the thrust collar and the thrust bearing through a conduction oil passage formed in the thrust bearing.

  Further, the present invention provides a turbocharger configured such that a jig can be attached to and detached from the tip of the compressor impeller, and the compressor impeller is rotated via the jig and screwed to the rotating shaft. It is related to.

  According to the present invention, the compressor wheel is provided at the tip of the rotating shaft extending from the turbine wheel, the rotating shaft is rotatably supported by the bearing housing, the turbine wheel is accommodated in the turbine housing, The compressor impeller is a supercharger housed in a compressor housing, and a fitting shaft portion and a screw portion are formed at a tip portion of the rotating shaft, and the fitting shaft portion is fitted to the compressor impeller. The screw part is screwed to the compressor wheel, the rotary shaft and the compressor wheel are connected, and the screw hole screwed into the screw part has a deepest position of the screw hole, the maximum diameter of the compressor wheel. Since the compressor impeller is drilled so as not to reach the position, stress generated in the compressor impeller during rotation of the compressor impeller is reduced, and the compressor impeller is reduced. It enables high-speed rotation becomes, thereby an increase in pressure ratio.

  According to the invention, the fitting shaft portion has a small diameter with respect to the rotating shaft, and a thrust collar and a thrust bearing are provided between the rotating shaft and the compressor impeller, and a thrust load is provided via the thrust bearing. Is supported by the bearing housing and the lubricating oil is supplied between the thrust collar and the thrust bearing through a conduction oil passage formed in the thrust bearing. It can be supported and lubricating oil can be supplied between the thrust collar and the thrust bearing.

  According to the present invention, a jig can be attached to and detached from the tip portion of the compressor wheel, and the compressor wheel is rotated through the jig and screwed onto the rotating shaft. Even when a large tightening torque is applied in the operation of tightening the compressor impeller to the rotating shaft, excellent effects such as no damage to the compressor impeller are exhibited.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  An example of a supercharger in which the present invention is implemented will be described with reference to FIGS.

  1 and 2, the same components as those shown in FIG. 8 are denoted by the same reference numerals, and the description thereof is omitted.

  The rotating shaft 2 formed integrally with the turbine impeller 7 is rotatably supported by the bearing housing 5 via the bearing 6. A portion of the rotating shaft 2 that extends further than the bearing 6 is configured by a fitting shaft portion 21 having a smaller diameter with respect to the rotating shaft 2 and a screw portion 22 having a smaller diameter than the fitting shaft portion 21.

  A blind screw hole 23 is formed in the disk portion 8 a of the compressor wheel 8, and the deepest position of the blind screw hole 23 (including the lower hole of the screw 23) is a maximum diameter position M of the compressor wheel 8. It is set not to reach. A fitting portion hole 24 having a diameter larger than that of the blind screw hole 23 is formed at the opening end of the blind screw hole 23.

  The compressor impeller 8 is screwed to the screw portion 22 and the fitting portion hole portion 24 is fitted to the fitting shaft portion 21 so that the core of the rotary shaft 2 and the compressor impeller 8 is aligned. It matches.

  A thrust collar 25, a spacer ring 26, a thrust collar 27, and an oil drain 28 are provided between the end face of the disk portion 8a on the turbine impeller 7 side and the end face of the rotary shaft 2 from the rotary shaft 2 side. A thrust bearing 29 provided between the thrust collar 25 and the thrust collar 27 is fixed to the bearing housing 5.

  By tightening and fixing the compressor wheel 8 to the screw portion 22, the compressor wheel 8, the rotary shaft 2, the thrust collar 25, the spacer ring 26, the thrust collar 27, and the oil drain 28 are formed. Integrate and rotate.

  The bearing housing 5 is provided with an oil supply port 31, and further provided with a plurality of branched oil passages 32 communicating with the oil supply port 31, and a part of the conduction oil passage 32 is open to the bearing 6. , A part is opened to the outer peripheral surface of the spacer ring 26 through the thrust bearing 29. Accordingly, a part of the supplied lubricating oil is supplied to the outer peripheral surface of the spacer ring 26 through the conducting oil passage 32 and to the opposing surfaces of the thrust bearing 29 and the thrust collars 25 and 27. ing.

  Thus, the thrust bearing 29 and the thrust collars 25, 27 are lubricated, and the thrust load acting on the rotary shaft 2 is supported by the bearing housing 5 via the thrust bearing 29. ing.

  Next, the case where the compressor wheel 8 is screwed to the rotary shaft 2 will be described.

  As shown in FIG. 3, a plurality of recesses 34 are formed on the same circumference at the distal end portion (hereinafter referred to as the distal end portion) of the disk portion 8a on the suction port 16 side. In the present embodiment, the concave portion 34 shows a hole with a circular cross section that is formed at a position equally divided into six circumferences.

  The concave portion 34 is used to attach and detach a jig for rotating the compressor wheel 8 and serves as a means for transmitting torque through the jig.

  4 and 5 show a jig 35. The jig 35 is made of steel or iron-based alloy steel, and includes a hexagonal head 36 and the head 36. The connector 37 has six protruding protrusions 37, and the connector 37 has a circular cross section, is located at a position equally divided by the circumference 6, and can be fitted into and removed from the recess 34.

  When the compressor impeller 8 is fastened to the rotary shaft 2, the connector 37 is fitted into the recess 34, and the jig 35 is attached to the tip of the disk portion 8a. A tool such as a spanner is applied to the head 36 to give a rotational force. The compressor wheel 8 is rotated via the jig 35, screwed onto the screw portion 22, and further tightened. After the compressor impeller 8 is attached, the jig 35 is removed.

  The number of the connectors 37 is determined by the magnitude of torque when tightening. Since the compressor wheel 8 is tightened through the high-strength jig 35, the jig 35 is not damaged, and torque is distributed and transmitted by the connector 37, so that the compressor The impeller 8 is not damaged, and a sufficient tightening force can be applied to the compressor impeller 8. It is to be noted that the number of the connecting members 37 is preferably six or more than six considering that the material of the compressor wheel 8 is aluminum or the like.

  The jig 35 and the disk portion 8a are engaged with each other in the form of a hexagonal hole drilled around the recess 34, projecting around the connector 37, and having a cross section of 6 It may be a corner.

  As in the present invention, the end of the rotary shaft 2 is screwed into the blind screw hole 23 without penetrating the compressor impeller 8, and the blind screw hole 23 formed in the compressor impeller 8 is perforated. Since the deepest position does not reach the maximum diameter position M of the compressor wheel 8, the portion where the centrifugal force is maximum is solid, and the stress generated by the centrifugal force is uniformly distributed, and the stress is applied to a specific part. Can be avoided.

  FIG. 6 shows the distribution of the ratio between the stress generated in the disk portion 8a of the compressor wheel 8 and the maximum stress generated in the conventional compressor wheel 8 when the compressor wheel 8 is rotated in the present invention. Since the deepest position of the blind screw hole 23 does not reach the maximum diameter position M, the stress at the maximum diameter portion is dispersed, and the maximum stress is generated over a wide range inside the disk portion 8a. It can be seen that it is significantly lower than before. The rotational speed of the compressor wheel 8 is the same as that of the present invention and the conventional example, and the stress distribution is obtained.

  Therefore, in the present invention, even if the rotational speed of the compressor impeller 8 is greatly increased, the compressor impeller 8 can be prevented from being damaged. That is, the pressure ratio can be greatly increased.

  Next, the case where the rotation balance of the compressor impeller 8 is adjusted will be described.

  A part 38 of the front end portion of the disk portion 8a is cut off, or a hole 39 is formed in the vicinity of the periphery of the front end portion, and a metal member having a large specific gravity, such as a copper wire, is embedded in the hole 39.

  Since the end portion exposed portion of the disk portion 8a is not subjected to a tightening tool or the like, there is no restriction when the portion 38 is cut off, and the rotation balance can be easily adjusted.

It is sectional drawing of the supercharger which concerns on embodiment of this invention. It is an expanded sectional view of the connection part of the rotating shaft and compressor impeller in this supercharger. It is a side view of the front-end | tip part of this compressor impeller. It is a side view of the jig | tool which can be fitted to the front-end | tip part of this compressor impeller. It is a front view of this jig. It is explanatory drawing which shows the stress distribution which generate | occur | produces when rotating the compressor impeller which concerns on this invention. It is explanatory drawing which shows the stress distribution which generate | occur | produces when rotating the compressor impeller of the conventional supercharger. It is sectional drawing of the conventional supercharger.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Supercharger 2 Rotating shaft 3 Turbine 4 Compressor 7 Turbine impeller 8 Compressor impeller 8a Disk part 13 Compressor housing 21 Fitting shaft part 22 Screw part 23 Blind screw hole 24 Fitting part hole part 25 Thrust collar 26 Spacer ring 27 Thrust collar 28 Oil drain 29 Thrust bearing 31 Oil supply port 32 Conducting oil passage 34 Concave portion 35 Jig 37 Connector

Claims (3)

  A compressor impeller is provided at the tip of a rotating shaft extending from the turbine impeller, the rotating shaft is rotatably supported by a bearing housing, the turbine impeller is accommodated in a turbine housing, and the compressor impeller is compressed by a compressor housing. A fitting shaft portion and a screw portion are formed at a tip portion of the rotating shaft, the fitting shaft portion is fitted into the compressor impeller, and the screw portion is the compressor. The screw shaft that is screwed onto the impeller is connected to the rotating shaft and the compressor impeller so that the deepest position of the screw hole does not reach the maximum diameter position of the compressor impeller. A turbocharger provided in the compressor impeller.   The fitting shaft portion has a small diameter with respect to the rotating shaft, and a thrust collar and a thrust bearing are provided between the rotating shaft and the compressor impeller, and a thrust load is supported by the bearing housing via the thrust bearing. The turbocharger according to claim 1, wherein lubricating oil is supplied between the thrust collar and the thrust bearing through a conduction oil passage formed in the thrust bearing.   The supercharger according to claim 1, wherein a jig is detachably attached to a tip portion of the compressor impeller, and the compressor impeller is rotated through the jig and screwed to the rotating shaft.

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