Komatsu Corporation

Takahisa Iino

Toshihiko Nishiyama

Hiroshi Sugito

Shuuji Hori

Daisuke Kozuka

Tetsuaki Ogawa

Yasuyuki Onodera

Fumihide Sato

Yoshiki Kanzaki

Hiroyasu Satou

Keiichi Inaba

A hydraulic servo drive device for driving a swing mechanism of a variable geometry turbocharger includes a servo piston connected to a driveshaft of the swing mechanism and a pilot spool that is accommodated in a center hole of the servo piston and slides by pilot pressure. A first hydraulic chamber to and from which pressure oil flows are provided in a housing. The servo piston separately includes a pressure port for introducing pressure oil from an outside, a first piston port for intercommunicating the center hole and the first hydraulic chamber, a second piston port for intercommunicating the center hole and the second hydraulic chamber, and a return port for exiting pressure oil.

Variable turbo supercharger and method of driving the same

A hydraulic servo drive device for driving a slide mechanism of a variable geometry turbocharger includes a servo piston connected to a driveshaft of the slide mechanism and a pilot spool that is accommodated in a center hole of the servo piton and slides by pilot pressure. A first hydraulic chamber and a second hydraulic chamber to and from which pressure oil flows are provided in a housing. The servo piston separately includes a pressure port for introducing pressure oil from an outside, a first piston port for intercommunicating the center hole and the first hydraulic chamber, a second piston port for intercommunicating the center hole and the second hydraulic chamber, and a return port for exiting pressure oil.

Provided are a variable geometry turbocharger in which a drain pipe from a hydraulic servo drive device can be omitted and in which a member for transmitting power of the hydraulic servo drive device can be efficiently lubricated, and a method of returning oil from the hydraulic servo drive device. The variable geometry turbocharger includes a slide mechanism for changing an opening degree of a nozzle, the hydraulic servo drive device for driving the slide mechanism by hydraulic pressure, and drain flow paths for delivering oil exhausted from the hydraulic servo drive device into an oil return chamber adjacent to a turbocharger body.

Variable turbo supercharger and method of returning oil from hydraulic drive

A turbocharger as a turbo machine includes: a compressor impeller () having a projected portion () at a center of a rear surface; a drive shaft () connected to a bottomed coupling hole () provided in the projected portion () of the compressor impeller () through interference fit only; and a sleeve () with a cylindrical portion () connected to the outer peripheral portion of the projected portion () of the compressor impeller () by fitting only. The sleeve () is formed of a material whose coefficient of linear expansion is smaller than that of the compressor impeller (). Accordingly, even when the coupling hole () in the projected portion () undergoes thermal expansion and the diameter of the coupling hole () increases, a connection between the drive shaft () and the coupling hole () can be prevented from being loosened since the radial increase thereof is suppressed by the cylindrical portion (). Thus, the state of the connection thereof can be well maintained.

Turbo machine, compressor impeller used for turbo machine, and method of manufacturing turbo machine

It is an object of the invention to provide a structure for connecting a compressor wheel and a shaft, which structure is not easily broken when rotated at high speed. A male screw is provided on an outer surface of a projection formed on the center of a rear of the compressor wheel, and a male screw is provided on a shaft. The compressor wheel and the shaft are connected with each other by a sleeve having female screws provided at each end thereof. An engagement portion is provided between the compressor wheel and the shaft.

Structure for connecting compressor wheel and shaft

There is provided a turbocharger whose constitution is compact, in which exhaust interference seldom occurs, and which can be applied also to an EGR type engine. In the turbocharger, an introduction part of an exhaust inflow passage possesses a partition part dividing a range from an inlet to a predetermined position in a downstream of the inlet into two exhaust inflow passages, a throttle part, whose sectional area becomes gradually small, from the inlet to a position where the partition part ceases, a joining part where exhaust gases passing through the left and right exhaust inflow passages are joined, and a diffuser part, whose sectional area becomes gradually large, from the joining part to a tongue part.

Turbocharger

One of the swing shaftsof the nozzle vanesis selected so as to operate as swing drive shaftthat projects to the outside. As the swing drive shaftis driven to revolve, all the nozzle vanesare driven to turn by a same angle by way of the driving leverand the coupling ringlinked to it. Therefore, it is only the swing drive shaftthat projects to the outside, the projecting part can be sealed in a simple and reliable manner to improve the sealing effect and the durability of the variable geometry turbocharger. Additionally, since the rotary motion of the swing drive shaftis directly used to driven the nozzle vanesto swing, the mechanism for transmitting the driving force is simplified.

Variable turbocharger

An opening of the variable nozzle of the exhaust turbine supercharger is set to and maintained at the maximum value in the constant operating state when the load is not more than a prespecified load level. The opening is gradually made smaller, when the load is not less than the specified load level, as the load becomes greater. When the load shifts from the high load region to the low load region, the variable nozzle is mere closed or maintained at the original opening, and when the operating state get close to the surging limit, the variable nozzle is more opened. When shifting from the low load region to the high load region, or when sifting from low speed to high speed, the variable nozzle is opened mace, and then closed to return to the constant operating state.

Variable nozzle opening control system for an exhaust turbine supercharger

In an internal combustion engine having an exhaust gas recirculation circuit, the efficiency of a turbocharger is raised in a wide engine rotational speed area and, even when a pressure in an intake circuit is higher than that in an exhaust circuit, an exhaust gas can be circulated. For this purpose, an openable intake throttle valve ( ) is provided on the more upstream side than an exhaust gas circulation position of the intake circuit ( ), or a narrow portion ( ) is formed on the exhaust gas circulation position of the intake circuit and an intake bypass circuit ( ) for bypassing the narrow portion is provided. Further, an intake and exhaust bypass circuit ( ) for connecting the intake circuit to the exhaust circuit ( ) is provided. Then, the opening degree of the intake throttle valve or intake bypass circuit and the opening degree of the intake and exhaust bypass circuit are adjusted so as to set the pressure at the exhaust gas circulation position of the intake circuit to be lower than that in an exhaust manifold ( ).

Growing community of inventors

Oyama, Japan

Takahisa Iino