JPS5824604B2 - supercharger - Google Patents

Description

[Detailed description of the invention] The invention relates to improvements in exhaust driven superchargers.

Two-stroke tasel engines and gasoline engines differ from four-stroke engines in that they do not have a process for discharging exhaust gas and sucking in air, so air is drawn in from the outside to scavenge combustion gas and fill the cylinder with fresh air. We need to forcefully send them in.

As a device for this purpose, there is a supercharger that compresses air from the atmosphere using a turbine or a compressor using exhaust gas from combustion.

This method is also applied to boiler ventilation.

An example of this type of supercharger is shown in FIG.

In the figure, 01 is a turbine wheel, 02 is a compressor wheel, 03 is a turbine casing, 04 is a compressor casing, 05 is a turbine shaft, 06 is a journal bearing, 07 is a thrust bearing, 08 is a thrust collar, 09 is an oil supply hole, 010 is the oil drain hole.

Exhaust gas from a diesel engine or boiler fed through a turbine casing 03 is applied to a turbine wheel 01 and converted into rotational energy.

There is a compressor impeller 02 at the other end of the turbine shaft 05, and by rotating the compressor impeller 02, air in the atmosphere is compressed and blown through the compressor casing 04 to an engine or a boiler.

Note that the turbine shaft 05 rotates while being supported by a journal bearing 06 and a thrust bearing 07.

Both bearings are located between the turbine wheel and the compressor wheel.

For reasons such as improving the efficiency and making the turbocharger more compact, the shaft is required to rotate at high speed, and therefore a type of bearing that is highly stable at high speeds, such as a floating push type, is adopted.

In addition, to remove the frictional heat resulting from high-speed sliding, lubricating oil is forcibly circulated by an external pump, and a cooler and filter are placed along the way.

However, the above conventional device has the following drawbacks.

(1) It is necessary to install a pump for lubricating oil supply and a cooler for cooling externally, which increases the number of parts and occupies a larger space in the overall structure (which leads to increased costs and makes the piping system more complicated).

(2) A seal is required between the turbine section and the compressor section for oil lubrication.

Particularly in the turbine section, shafts, bearings, and seals were damaged by carbonized solid carbon produced by the high temperature of the turbine due to oil leakage during shutdown, which could lead to accidents.

(3) When the oil is used as the engine system oil, the oil is dirty, and the dust that gets into the bearings can cause scratches or seizures.

(4) Since oil is consumed, replenishment and maintenance are time consuming.

(5) When the turbine gas temperature is increased to improve thermal efficiency, the bearings on the turbine side become hot, so pumps and coolers must be made larger in order to increase the amount of oil or lower the oil temperature.

An object of the present invention is to provide a supercharger that eliminates the above-mentioned drawbacks, and its features include (f) a vertical shape with the turbine wheel placed above and the compressor wheel placed below; (a) The journal bearing is an air-lubricated tilting pad type, and one piece is placed between the compressor and the turbine, and the thrust bearing is an oil-lubricated spherical spiral grooved bearing, which is installed at the end of the compressor. A lubricated spherical spiral grooved thrust bearing is installed in a closed oil reservoir, and the oil is cooled by the compressor intake air through cooling fins around it, eliminating the need for forced oil circulation or forced cooling equipment. .

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view showing a supercharger according to an embodiment of the present invention;
FIG. 3 is a sectional view taken along the line ■--■ in FIG. 2.

In the figure, 1 is a turbine wheel, and 2 is a compressor wheel, which are located below the turbine wheel 1 and arranged vertically.

3 is a turbine casing, and 4 is a compressor casing.

Reference numeral 5 denotes a turbine shaft, which is a cylindrical shaft provided on the turbine wheel 1 and is connected to a ring-shaped portion provided on the compressor wheel 2, and is connected to the turbine with a tie bolt 6 passing through the cylindrical shaft. The blade wheel 1 and the compressor blade wheel 2 are fastened together.

Reference numeral 1 denotes an air-lubricated tilting pad type journal bearing, which is provided to support the turbine shaft 5.

8 is a spiral grooved spherical shaft, which is attached to the compressor wheel 2.
The tie bolt 6 is provided at the lower end of the axis thereof, that is, at the end face of the tie bolt 6.

Reference numeral 10 denotes an oil-lubricated spherical spiral grooved thrust bearing, which supports the spherical shaft 8 in an oil reservoir 9 provided across a "rubber"-shaped opening formed in the inner casing of the compressor casing 4. It is set up to do so.

A plurality of cooling fins 11 are provided to protrude from the compressor casing 4 into the oil reservoir 9.

The operation in the case of the above configuration will be described.

(1) High-pressure exhaust gas is sent from the diesel engine or boiler through the turbine casing 3 to the turbine blade wheel 1.
gives energy to rotate the turbine shaft 5.

At this time, air is compressed by the compressor wheel 2 and blown to the combustion chamber or combustor through the compressor casing 4.

(11) The journal part of the turbine shaft 5 is supported by a tilting pad type journal air bearing 1, and is initially in solid contact with the bearing, but as the rotation increases, an air film is generated due to the dynamic pressure between the bearing and the turbine shaft 5. The shaft and bearings are completely separated and air lubricated.

(iii) A small-diameter spherical spiral grooved bearing 10 at the end of the compressor is lubricated with oil and carries a thrust load.

(iV) By making the turbocharger vertical, the weight of the rotating body including the shaft and impeller during startup is supported by the oil-lubricated thrust bearing 10, reducing the burden on the air-lubricated journal bearing 7. .

As described above, the present invention has the following effects.

(1) Since the journal bearing 7 is an air bearing, friction loss horsepower is small.

(2) Since the journal bearing 7 is of the tilting pad type, thermal expansion of the shaft can be tolerated and cooling is not required.

(3) Although the journal bearing 1 is an air bearing and the thrust bearing 10 is an oil bearing, the oil reservoir 9 has cooling fins 11.
Built-in, there is no need for an external oil pump, cooler, or filter.

(4) By providing the thrust bearing 10 at the end of the compressor, it is possible to use a spherical spiral grooved bearing with a small shaft diameter.

Therefore, oil-lubricated bearings with low friction loss are used.

:5) By combining one self-aligning spherical spiral grooved thrust bearing 10 and one tilting pad journal bearing 70, the assembly accuracy of the bin can be reduced.

(6) Since the supercharger rotates at high speed, the temperature of the lubricating oil increases, but the cooling fins 11 provided in the oil reservoir 9 can cool the lubricating oil.

(The tilting pad journal gas bearing 7 and the spherical spiral grooved thrust bearing 10 both have excellent high-speed stability, making it possible to create a compact, high-output supercharger.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing a conventional supercharger, Fig. 2 is a cross-sectional view showing an embodiment of the supercharger according to the present invention, and Fig. 3 is a cross-sectional view taken along the -■ arrow in Fig. 2. . 1... Turbine impeller, 2... Compressor impeller, 3... Turbine casing, 4...
... Compressor casing, 5 ... Turbine shaft, 6 ... Tie bolt, 1 ... Air lubricated tilting pad type journal bearing, 8 ...
... Spiral grooved spherical shaft, 9 ... Oil reservoir, 1
0... Oil-lubricated spherical spiral grooved thrust bearing, 11... Cooling fin.

Claims (1)

[Claims] 1. A supercharger configured with a turbine wheel driven using exhaust gas and a compressor wheel coupled coaxially, with the compressor wheel side facing downward, and having a vertical shape,
The drive shaft connecting the turbine impeller and compressor impeller is supported by a tilting pad type journal bearing, and the compressor impeller axle is positioned in an oil sump surrounded by a compressor inlet casing forming an air intake passage. A supercharger characterized in that a spherical thrust bearing is provided at the lower end, and a plurality of cooling fins are provided in the oil reservoir and protrude from the compressor inlet casing.