Rotary kinetic fluid motors or pumps – Selectively adjustable vane or working fluid control means – Upstream of runner
Reexamination Certificate
2002-02-25
2004-05-18
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
Selectively adjustable vane or working fluid control means
Upstream of runner
C060S602000, C029S889220
Reexamination Certificate
active
06736595
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention, as used in a supercharger (an exhaust gas turbocharger) of internal combustion engines and so forth, relates to an adjustable nozzle mechanism for variable capacity turbines and its production method, and to a radial flow turbine configured to make an actuating gas flow from the spiral scroll formed in a turbine casing to the turbine rotor through the multiple nozzle vanes having wings of variable angle.
2. Description of the Related Art
In order to make a good match with regard to an internal combustion engine, between the outflow exhaust gas volume from the engine and the actuating gas flow volume which should be determined for the optimum operation condition of the supercharger, variable capacity superchargers, equipped with a variable capacity turbine capable of changing the exhaust gas volume to be sent from the spiral scroll to the turbine rotor in accordance with the operating condition of the engine, have been in widespread use in recent years.
A supercharger with such a variable capacity turbine is equipped with the adjustable nozzle mechanism in order to change the wing angle of the nozzle vane by rotating the nozzle vane with a link assembly so that it is capable of being driven for rotation around the turbine rotor shaft by the actuator through the actuator rod and the driving lever.
For a method of assembly and adjustment of such a variable nozzle mechanism, the invention of Japanese patent number 3,085,210 has been proposed.
In the concerned invention, a jig should be placed at the inner radius of the nozzle vane to perform setup for perfect closing of the nozzle vane and the link assembly to be driven for rotation around the turbine rotor shaft. The jig can be put in contact with the rear edge of the nozzle vane. The stopper pin is mounted after the nozzle vane and the lever plates are welded together upon putting the nozzle vane in contact with the jig in a state that the stopper pin, that is to be fitted into long slots provided at multiple positions along the circumferential direction of the link plate, is made non-functional or non-existing, and upon fitting the matching pin into the phase matching hole to finalize the entire link assembly in the perfect closing phase.
However, problems such as the following are concerns with the invention of Japanese patent number 3,085,210. Two different processes are required, one of which is to put the jig in contact with the nozzle vane in the nozzle vane-free state, wherein the stopper pin to be fitted into the long slots of the link plate is non-functional, and the other is to mount the stopper pin after welding the nozzle vane and the lever plate in the perfect closing phase of the entire link assembly with the matching pin fitted into the phase-matching hole. This in turn requires more assembling jigs, making the adjustable nozzle mechanism assembly and the related adjustment work troublesome, with additional man-hours resulting in a cost increase.
In addition, on the basis of the conventional art in which the structure becomes complex due to the link position determining pin included therein with the stopper pin fitted into the long slot at multiple positions in the circumferential direction of the link plate, the number of the part category and the number of parts themselves will therefore increase considerably. As a result, the device costs will increase accordingly.
Furthermore, as the setup of the total adjustable nozzle mechanism should be carried out by means of fitting the stopper pin into the long slot at multiple positions in the circumferential direction of the link plate and by means of making a match of the relative angle of the contact of the jig at the nozzle vane rear edge against the lever plate, the setup of the perfect closing may vary to cause a setup error. The perfect closing position of the adjustable nozzle mechanism must be determined primarily by the dimensional accuracy of the component parts, which may make it difficult to obtain the proper setup accuracy.
SUMMARY OF THE INVENTION
In consideration of the problems with the conventional art mentioned above, the object of this invention is to propose a method to realize assembly and adjustment, and the related assembly and adjustment facilities for the variable capacity turbine, requiring neither adjustment of the perfect closing position in the nozzle assembly nor the jigs for assembly and adjustment thereof, by which the adjustment work can be simplified to decrease man-hours, as well as assembly and adjustment costs. The structure can also be simplified to decrease part category numbers and the number of parts itself, thus decreasing part costs and furthermore enabling the nozzle vane setup of the adjustable nozzle mechanism to a comparatively high degree of accuracy without being influenced by the degree of dimensional accuracy of the component parts, such as the nozzle vane and the link assembly.
In order to solve the concerned problems, the variable capacity turbine for applying this invention comprises a number of nozzle vanes, which are arranged along the circumference of the turbine and provided on nozzle shafts which are supported on a turbine casing in such a way that the nozzle vanes can rotate, and which vary the vane angle. A nozzle driving member drives the nozzle vanes, and is enabled to rotate around the turbine shaft by an actuator. A turbine rotor is set free for rotation on an inner radial side of the nozzle vanes. The variable capacity turbine is driven for rotation of the turbine rotor by conducting the actuating gas from the scroll in the turbine casing in the inner radial direction through the nozzle vanes to the turbine rotor.
In the event of manufacturing the adjustable nozzle mechanism used in such variable capacity turbine, it is distinguished by a manufacturing method according to this invention, which comprises providing a plurality of joint members (lever plates) which are the same in number as the nozzle shafts, and connecting the plurality of nozzle vanes and the nozzle driving member (link plate), fitting and fixing each nozzle shaft to one end of each lever plate after setting a predetermined positional relationship between the wing angle of the nozzle vanes and the fitting direction of the fixing section of the lever plate; and engaging another end of each lever plate with the nozzle driving member (link plate).
For the concrete fixing method of the nozzle shaft to joint member (lever plate), the method comprises forming a coupling hole in each joint member (lever plate), then forming a flat or curved surface on one sidewall of each coupling hole. A coupling shaft is provided with a fitting surface on the end of the nozzle shaft for nozzle vane, the fitting surface corresponding to the shape of the coupling hole of the joint member (lever plate) for creating a stopper. The coupling shaft is filled into the coupling hole without causing plastic deformation at the coupling shaft or coupling hole, and a stopper surface of the shaft is engaged with a stopper surface on the coupling hole so that the joint member (lever plate) and the nozzle shaft cannot rotate relatively because of the stopper. Finally, processing for anti-decoupling is carried out to prevent the nozzle shaft from squeezing out of the side surface of the joint members by using the chamfered portion having a larger diameter (chamfered portion) at the edge portion of the nozzle shaft.
The anti-decoupling is preferably done by punching the shaft edge of the coupling shaft by using the chamfered portion at the edge after engaging the coupling hole of the joint member with the coupling shaft of the nozzle shaft. The anti-decoupling process at the edge can be substituted by light welding or the like.
This invention further features that the concrete engaging method of the joint members (lever plate) with the nozzle driving member (link plate) is to fit the slots with the fitting pins equal in number to the joint members. The fitting pins protrude along the circumferential direction on
Jinnai Yasuaki
Sakamoto Taro
Look Edward K.
McAleenan J. M.
Mitsubishi Heavy Industries Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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