JPS58138223A - Cooling device of turbo-supercharger - Google Patents

Abstract

PURPOSE:To prevent the seizure, abrasion, etc. smoothly by feeding a part of the supercharged air for cooling to a vacant chamber provided between a turbine housing or backplate and a bearing housing. CONSTITUTION:When the supercharged pressure becomes a fixed value or more, an opening/closing valve means 22 is opened and a part of the supercharged air is circulated through an inlet passage 20, inlet communicating path 23, vacant chamber 5, outlet communicating path 24, outlet passage 21 and compressor intake passage 13. A backplate 4, bearing housing 2 and turbine wheel shaft 6 are cooled by the supercharged air flowed in the vacant chamber 5.

Description

[Detailed description of the invention] The present invention relates to a cooling device for a turbocharger.

In a turbocharger mounted on a gasoline or diesel engine, a back plate 4 is installed on the spine of the turbine wheel 3 to prevent the exhaust gas inside the turbine housing 1 from coming into direct contact with the bearing housing 2, as shown in FIG. At the same time, a cavity 5 sealed from the outside is formed between the plate 4 and the bearing 1, and the air trapped in the cavity is used as a heat insulating layer. The amount of heat transferred from the back plate 4 to the bearing housing 2 is reduced. In this way, conventionally,
Turbine wheel shaft6. Considering that it is not sufficient to cool the bearing mechanism by supplying lubricating oil from the engine's lubrication system to the bearing mechanism 9 formed by the bearing 8 of the bearing 7 and the bearing 1. and block the transfer of exhaust heat to the bearing mechanism part 9 by using the above-mentioned heat insulating air layer,
This assists the cooling effect of the lubricating oil (・
Ta.

However, since the air in the cavity 5 remains confined within the cavity, the air also becomes high in temperature, making it difficult to enhance the heat insulation effect of the insulating air layer in the cavity 8. The high heat of the bank plate is transmitted to the bearing mechanism section 9, increasing the thermal load on the mechanism section 9 and causing seizure of the mechanism section 9 at an early stage.

The present invention has been devised in view of the above.

Air is allowed to flow into a cavity existing between the turbine housing or back plate and the bearing housing, and the air after passing through the cavity flows out into the intake system pipe on the compressor inlet side. The main feature of this system is a cooling system for a turbocharger that is characterized by the following: Since it is configured to allow air to flow in and out of the cavity, the flowing air in the cavity enhances the heat isolation effect, which in turn improves the cooling of the turbine. This has the effect of effectively suppressing transmission of high-temperature heat possessed by the housing or bank plate to the bearing housing side.

The present invention will be described below with reference to a first embodiment shown in FIG. Parts or members equivalent to those of the conventional device shown in FIG. 1 will be denoted by the same reference numerals as those shown in FIG. 1, and their explanation will be omitted. 10 is a turbine inlet side passage connected to the turbine housing 1; 11 is a turbine outlet side passage; 12 is a compressor wheel; 13 is a compressor inlet side passage connected to the compressor housing 14;
15 is a passage on the compressor outlet side; 16 is an oil inlet bored in the bearing housing 2 and communicates with the engine lubricating oil system; 17
18 is an oil outlet, 18 is an oil passage, and 19 is a thrust bearing. Reference numeral 20 indicates an inflow passage provided to communicate between the compressor outlet side passage 15 and the empty chamber 5, 21 indicates an outflow passage provided between the compressor inlet side passage 16 and the empty chamber 5, and 22 indicates an outlet passage provided between the compressor outlet side passage 15 and the empty chamber 5. The on-off valve means 2 is provided in the inflow passage 20 and only opens when the supercharging pressure exceeds a certain value.
2 is the one that operates to open. This opening/closing valve means 22 uses a check pulp mechanism which is known per se.

A solenoid valve that is opened and closed by a signal from a pressure sensor provided in the compressor outlet passage 15 may be used.

Reference numeral 23 designates an inflow communication passage bored in the bearing housing 2 and communicates the inflow passage 20 with the cavity 5, and 24 an outflow communication passage that communicates with the same outflow passage 21.

Since this embodiment has the above configuration, when the turbocharger is in operation, if the boost pressure in the compressor outlet passage 15 is below a certain value, the on-off valve means 22 is closed, and the turbocharger is not supplied to the inflow passage 20. There is no flow of energy. When the boost pressure exceeds a certain value, the on-off valve means 22 opens.

Due to the negative pressure in the compressor inlet side passage 13, the supercharged air flows into the cavity 5 through the inflow passage 20, and after flowing in, the supercharged air flows back to the compressor inlet side passage 13 from the outflow passage 21.

According to this embodiment, when the supercharging pressure exceeds a certain value, the on-off valve means 22 is operated to open, and a part of the supercharging air flows into the inflow passage 20.
．． Inflow communication passage 23. Vacant room5. Outflow communication passage 24. Outflow passage 21. The air is forced to circulate to the compressor inlet side passage 13, and the heat of the back plate 4, the bearing housing 2 side, and the turbine wheel shaft B can be efficiently lowered by the supercharging air flowing in the empty chamber 5. With.

Since a heat insulating air layer is formed by the supercharged air in the empty chamber, heat transfer from the back plate 4 to the bearing housing 2 can be effectively suppressed, and the temperature of the bearing mechanism part 9 can be regulated below a certain value. This makes it easier to cool the turbo supercharger overall.

Furthermore, it has an excellent effect of smoothly preventing seizure, burnout, sludge formation of lubricating oil, and abrasion caused by this. In addition, even if exhaust gas leaks into the cavity 5 from between the back plate 4 and the turbine wheel shaft 6, it will be sucked in by the negative pressure of the compressor inlet passage 13, so that the exhaust gas will not be released into the atmosphere. Never released.

In the above embodiment, the opening/closing operation is performed by the boost pressure using the opening/closing valve means 22, but this may be switched manually, or the opening/closing operation may be performed by detecting the temperature of the bearing housing 2 or by detecting the exhaust pressure. It may be something that activates it. Further, as in the above embodiment, the on-off valve means 22 is connected to the inflow passage 20.
It is also possible to have a structure in which there is no such provision.

Next, referring to a second embodiment of the present invention shown in FIG. In this case, the turbine housing 1 is formed by a space separated by the bearing housing 2, but the only difference in the second embodiment is that it is formed by a space separated by the turbine housing 1 and the bearing housing 2. , the other structures are almost the same.

Also in the case of the structure of the second embodiment, a part of the supercharged air that has flowed into the empty chamber 5 flows into the air compressor inlet side passage 13, so fresh air is supplied into the empty chamber 5, and the empty chamber This has the effect of effectively disconnecting the back plate 4 from heat and suppressing the temperature rise of the bearing mechanism section 9.

Above 1. In both of the second embodiments, the inflow passage 2° is structured to communicate with the humbresser outlet side passage 15, but the inflow passage 20 or the inflow communication passage 23 may simply be opened to the atmosphere. And in this case.

Atmospheric air flows into the empty chamber 5 due to the suction negative pressure of the air compressor inlet passage 13, so that the above-mentioned first. It has the same effect as the second embodiment. It goes without saying that a filter device may be appropriately installed in the passageway of the side air-open end cage.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional device, FIG. 2 is a cross-sectional view of a first embodiment of the present invention, and FIG. 6 is a cross-sectional view of a second embodiment of the present invention. 1; Turbine housing, 2; Bearing nozzle. 4; back plate; 5; empty chamber. 9; Bearing mechanism section. 13; Humpretusa entrance side passage.

Claims (1)

[Claims] The air is allowed to flow into the hollow space between the turbine housing or the back plate and the bearing housing, and the air after passing through the space is allowed to flow out into the intake system pipe on the inlet side of the humbretsu. Features of turbocharger cooling system