JPS5939930A - Turbocharger - Google Patents

Abstract

PURPOSE:To prevent burning of a bearing and deterioration of oil by providing a circular gap conducting with the atmospheric air between a center housing and a turbine housing. CONSTITUTION:Upon abrupt stoppage of an engine immediately after heavy load operation, heat will flow in from the turbine housing 4 through the joint 17 and transmitted from the outer wall of the center housing 6 through an oil feed hole 9 and the outer wall of the oil path 10 to the bearing 7. A portion of the heat from the turbine housing 4 is blocked by a gasket 17 at the joint while a portion of heat passed through the joint is lost through cooling effect due to natural convection of air existing in the gaps 16, 12 conducted to the atmospheric air when transmitting on the outer wall of the center housing 6 and a portion is diffused when transmitting on the outer wall of the oil path 10 and the oil feed hole 9 thereby only slight heat is transmitted to the bearing 7.

Description

[Detailed description of the invention] The present invention relates to improvements in turbochargers.

A turbocharger is a type of supercharger, and it is well known that the turbocharger has characteristics such as no power loss due to vortex-generating supercharging that operates an intake compressor using engine exhaust energy.

Figure 1 shows the entire structure of a relatively small turbocharger for automobiles (Japanese Unexamined Patent Publication No. 138421/1983).
Exhaust turbine 1 that generates rotational force by receiving engine exhaust energy and compressor turbine 2 that pressurizes intake air
are attached to a common turbine shaft 3, and all of the high-temperature, high-pressure exhaust gas is introduced into the exhaust turbine 1 through a scroll-shaped turbine housing 4, while the rotational force generated at this time is used to drive the compressor turbine 2. The system drives the engine and supplies overpressure air to the engine via the combretsu 1 housing 5f, which also forms a scroll.

The turbine shaft 3 is supported via a floating bearing 7 in a hollow center housing 6 located between the housings 4 and 5, and a thrust bearing is provided for positioning the shaft 3 in the thrust direction (horizontal direction in the figure). 8 is arranged on the Combretu Sano 1 Uging 5 side.

Lubricating oil (hereinafter referred to as oil) introduced from the oil supply hole 9 in the upper part of the center housing 6 reaches the oil passage 10 and enters the small hole 10a.
, 10b to lubricate the thrust bearing 8 and floating bearing 7, respectively.

In addition, the male part 6af of the center housing 6Fi and the female part 4aK of the turbine housing 4 are joined, and the flange part 6b and the flange part 4b of the turbine housing 4 are connected.
A gap 12 is provided in the middle as a heat insulating layer, and these 1
It is fastened by a band coupling 1-IK arranged around the outer periphery of the flange portions 6b and 4b.

Since the exhaust gas flowing through the internal space (scroll) 4C of the turbine housing 4 has a high temperature, when the gas heat is transferred to the center housing 6, the temperature of the bearing 7 increases and the lubrication conditions deteriorate.

Therefore, in order to prevent the center housing 6 from directly receiving radiant heat, a heat insulator 13 in the shape of a cylinder with a bottom is installed at the joint between the male part 6a of the center housing 6 and the female part 4a of the turbine housing 4. Since the heat transfer path between the joint part 4a and the bearing 7 is short, when the engine suddenly stops immediately after high-load operation, the supply of lubricating oil is cut off at the same time as the turbine housing engine stops. Bearing 7t? The temperature rises, causing the bearing 7 to melt (-
There was a problem that the oil deteriorated more quickly.

The present invention provides a connecting portion between the center housing and the turbine housing closer to the exhaust turbine than the fastening portion, and connects the center housing and the turbine housing by a flange 11.
The present invention aims to solve the above tIL problem by providing an annular gap communicating with the atmosphere between the joint and the fastening part and by lengthening the heat transfer path from the joint.

Hereinafter, the present invention will be explained based on the illustrated embodiments, and the same components as in FIG.

In FIG. 2, the flange portion 6d of the center housing 6
and the turbine housing 40 stages + 1 part 4d are joined with the heat insulator 13 in between, but the joint area is made to be the minimum area sufficient for strength, and the center housing 6 and the turbine housing 4 are connected at this joint part.
For this purpose, a sufficient gap 12S is provided at the fastening portion where the flange portion 6b of the center housing 6 and the flange portion 4b of the turbine housing 4 face each other. It is fastened with a band coupling 11 (not shown).

Furthermore, the joint portion is larger than the fastening portion in the exhaust turbine 1.
An annular gap 16 communicating with the atmosphere is formed between the joint portion and the fastening portion.

The bearing 7 is supported on the center housing 6 by a stay 6e having sufficient strength.
A large cooling passage 15 is formed inside.

Further, the oil passage 10 is provided with an oil jet (IOC) and the oil supply hole 9 is provided with a small hole 9ai, so that the oil ejected from the oil jet 10C cools the wall 6f of the outer peripheral portion in contact with the ring seal 14, and flows out from the small hole 9a. The oil in the stay is cooled together with the oil in the oil passage 10 at t7.

However, the reference numeral 17 is a gas sheet as a heat insulating material, and a thermally sprayed ceramic layer may also be used.

With this configuration, when the engine is suddenly stopped immediately after high-load operation, heat from the turbine housing 4 flows into the joint from the outer wall of the center housing 6 to the oil supply hole 9. It is transmitted to the bearing 7 via each outer wall of the oil passage 10.

However, part of the heat from the turbine housing 4 is first blocked by the gasket 17 at the joint, and the heat that has passed through the joint passes through the gap 16 (and 12) communicating with the atmosphere while being transmitted through the outer wall of the center housing 6. ) Some of the heat is lost due to the cooling effect due to natural convection of the air present in the oil supply hole 9 and the oil passage 10, and some of it is further diffused while passing through the outer walls of the oil supply hole 9 and the oil passage 10, so that the amount of heat that reaches the bearing 7 is negligible. becomes.

On the other hand, the heat transmitted through the ring seal 14 is transferred to the ring seal 14 by the oil jetted from the oil jet 10C.
Even when the engine is stopped, the wall portion 6f of the outer peripheral portion in contact with the bearing 7 is forcibly cooled by an external pump (not shown) for a predetermined period of time even when the engine is stopped, so that the flow of heat absorbed by the wall portion 6f and reaching the bearing 7 is extremely small.

As a result, the temperature rise of bearing 7 was reduced by 11, and the old slip staining condition was maintained well. In addition, the two points in the figure 'f f3i! As shown in FIG. Forced cooling may be used. .

The bearing 7 shown in FIG. 2 is one full floating bearing, but it may be two full floating bearings as shown in FIG. 1, or a bearing of a similar type. According to the present invention, the joint portion between the center housing and the turbine housing is provided closer to the exhaust turbine than the fastening portion, a gap communicating with the atmosphere is provided between the joint portion and the fastening portion, and a gap is provided inside the center housing. Also, a large cooling passage is provided on the exhaust turbine side to reduce the heat transfer path and reduce the amount of heat flowing into the bearing, which has the effect of preventing damage such as seizure of the bearing and deterioration of the oil.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a conventional example, and FIG. 2 is a longitudinal sectional view of an embodiment of the present invention. 1... Exhaust turbine, 4... Turbine housing,
4b...Flange part, 4d...Stepped part, 6...Center housing, 6b, 6d...Flange part, 11.
...V-band coupling, 16...gap. Patent applicant: Nissan Motor Co., Ltd., 1 Figure 1 Figure 2

Claims (1)

[Claims] In a turbocharger in which the center housing is fastened to the turbine housing with a V-band coupling or bolts, the joint between the center housing and the turbine housing is provided closer to the exhaust turbine than the fastening part, and the center housing and the turbine head are connected in a 7-lunge configuration. Jointed well,
A turbocharger characterized in that an annular gap communicating with the atmosphere is provided between a joint part and a fastening part.