JPH0117620Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a thrust bearing device for an air bearing type turbocharger that can be applied to a turbocharger for an automobile engine.

(Prior art) Conventional turbochargers employ oil-lubricated bearings to support ultra-high-speed rotors (more than 100,000 rpm). Further, unlike this, a bearing device for a turbocharger using an air bearing has been proposed in an earlier application (Japanese Patent Application No. 182,644/1982) filed by the present applicant.

(Problems to be Solved by the Invention) However, in the case of the oil-lubricated type, as the oil deteriorates, the oil becomes carbonized (sludge) due to the high-temperature exhaust heat from the turbine side. When this sludge builds up on the bearing, oil may not be supplied to the bearing, or the bearing may be damaged by hard carbon, causing problems such as the turbocharger not rotating properly. There was a drawback. Therefore, in order to prevent the oil used from deteriorating, it was necessary to change the oil every 5,000 km, resulting in a heavy burden on the user. The latter air bearing system does not have the above-mentioned problem with oil, but there is a problem with holding the thrust bearing that supports the shaft that connects the turbine and compressor.

The present invention was proposed in order to eliminate the above-mentioned conventional drawbacks, and its purpose is to provide a thrust bearing device in which the thrust bearing can be held more easily by providing a fixing member in a turbocharger employing an air bearing. It is something to do.

(Means for solving the problem) In order to achieve this objective, the present invention has an air type radial bearing and a repulsion type magnetic thrust bearing,
In an air bearing type turbocharger in which a turbine rotor and a compressor rotor are installed on both sides of the shaft, on the outer peripheral side surface on the turbine rotor side,
a ring-shaped protrusion that fits into a ring-shaped groove formed on the compressor-side surface of the bearing housing; and a stepped portion of a holding member that holds the housing and the permanent magnet on the compressor rotor side of the magnetic thrust bearing. The compressor rotor has an inner circumferential side surface on the turbine rotor side and an inner circumferential surface that comes into contact with the compressor rotor, and a stepped portion shaped to sink into the outer circumferential corner of the turbine rotor side of the compressor rotor is provided on the inner circumferential side surface on the compressor rotor side. In addition, a fixing member is provided on the outer circumferential surface of the bearing housing and has a threaded portion that is screwed into the bearing housing, and this is used as a means for solving the problem.

(Function) When the threaded portion of the fixing member configured as described above is screwed into the bearing housing, the ring-shaped protrusion on the side surface of the outer circumferential portion on the turbine rotor side fits into the ring-shaped groove of the housing, and at the same time, the inner surface on the turbine rotor side The peripheral side surface is in close contact with the stepped portion of the permanent magnet holding member located on the side of the housing and the compressor rotor, and the inner circumferential surface is fitted into the stepped portion, so that the holding member is pressed against the permanent magnet. Fix it. After that, when the compressor rotor is attached to the shaft, the stepped portion of the fixing member is fixed by being inserted into the outer peripheral corner of the rotor on the turbine rotor side. The close contact between the stepped portion and the stepped portion of the holding member prevents air pressure from leaking from the compressor, and also makes it possible to form a diffuser portion that converts dynamic pressure into static pressure.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. A turbocharger 1 includes a turbine housing 4 having an exhaust inlet 2 and an exhaust outlet 3 of an exhaust passage for engine combustion gas, an air inlet 5 of an engine intake passage, and an air inlet 5 of an engine intake passage. A compressor housing 7 having a compressed air outlet 6, a turbine rotor 8 located between the two housings 4 and 7, located in the exhaust passage of the turbine housing 4 at one end, and an intake passage of the compressor housing 7 at the other end. The compressor rotor 9 is provided with a bearing housing 11 that supports a shaft 10 to which a compressor rotor 9 is attached.

On the other hand, a pneumatic radial bearing 12 is disposed between the outer circumferential surface of a substantially central portion of the shaft 10 and the inner circumferential surface of a bearing housing 11 facing the shaft 10. Also, on the compressor side of the shaft 10,
A disk-shaped permanent magnet 13 is inserted and fixed through a bush 14, and the outer periphery of the magnet 13 is connected to the bearing housing 1 through a ring member 15 and a spacer 16.
It is held on the inner peripheral surface of 1. Also, permanent magnet 13
On both sides of the bearing housing 1, disk-shaped permanent magnets 17 and 18, which are magnetized so as to repel each other, face each other.
1, and these constitute a repulsion type magnetic thrust bearing 19. Further, the permanent magnets 17 and 18 are held in the bearing housing 11 via holding members 20 and 21, respectively. 22 is a snap spring, 23 is a seal plate, and 24 is an air intake port.

Reference numeral 25 denotes a fixing member, which includes a ring-shaped protrusion 27 that fits into a ring-shaped groove 26 formed on the compressor-side surface of the bearing housing 11 on the outer peripheral side surface of the turbine rotor 8 side, and the housing 11 and the holding member. The inner peripheral side surface 29 and the inner peripheral surface 30 on the turbine rotor 8 side that contact the stepped portion 28 of the compressor rotor 9 and the outer peripheral surface on the turbine rotor 8 side of the compressor rotor 9 are In addition to providing a stepped portion 31 shaped to fit into the corner,
A threaded portion 3 screwed into the bearing housing 11 on the outer peripheral surface
It has 2.

Next, the action will be explained. When the turbocharger 1 operates, high pressure air is supplied to the pressurized air outlet 6 by the compressor rotor 9. In the thrust bearing 19, the permanent magnets 17 and 18 on both sides of the permanent magnet 13 are magnetized so as to repel each other, thereby restricting the movement of the shaft 10 in the thrust direction.

The fixing member 25 is screwed into the bearing housing 11, the ring-shaped protrusion 27 fits into the ring-shaped groove 26 of the housing, and at the same time the inner peripheral side surface 2
9 is a housing 11 and a compressor rotor 9
The permanent magnet 17 located on the side is in close contact with the step 28 of the holding member 20, and the inner peripheral surface 30 is in close contact with the step 28.
By fitting the holding member 20 into the permanent magnet 17, the holding member 20 is pressed and fixed against the permanent magnet 17. Then shaft 10
When the compressor rotor 9 is attached to the compressor rotor 9, the stepped portion 31 of the fixing member 25 is fixed by being inserted into the outer peripheral corner of the compressor rotor 9 on the turbine rotor side. Step portion 2 of this fixing member 25 and holding member 20
8, the air pressure is prevented from leaking by the compressor, and the outermost surface of the fixing member 25 and the stepped portion 31 form a diffuser portion that converts dynamic pressure into static pressure.

(Effects of the invention) Since the present invention is configured as explained in detail above, the inner circumferential side surface of the fixed member on the turbine rotor side is in close contact with the stepped portion of the housing and the permanent magnet holding member, and the turbine rotor The fixing member is fixed by being inserted into the outer peripheral corner of the side compressor rotor. Therefore, it is possible to prevent air from leaking from the compressor, and to form a diffuser section that converts dynamic pressure into static pressure. In addition, by screwing in the threaded part of the fixing member, the permanent magnet can be fixed by being pressed by the holding member, which saves installation space compared to conventional methods that use machine screws or snap springs to lock the thrust bearing. It can be made smaller, the thrust bearing can be held more reliably than conventional air bearing systems, the structure is compact and highly reliable, and it can be provided at low cost.

[Brief explanation of the drawing]

The drawing is a side sectional view of an air bearing type turbocharger showing an embodiment of the present invention. Explanation of the main parts of the diagram: 1...Turbocharger, 9...Compressor rotor, 10...Shaft, 11...Bearing housing, 12...Pneumatic radial bearing, 13, 18...Permanent magnet, 17...
outermost permanent magnet, 19...repulsion type magnetic thrust bearing, 20... holding member, 25... fixing member,
26...Ring-shaped groove, 27...Protrusion, 28...
Stepped portion, 29...inner surface, 30...inner peripheral surface, 31...
Stepped part, 32...screw part.

Claims (1)

[Scope of utility model registration request] In an air bearing turbocharger that has an air radial bearing and a repulsive magnetic thrust bearing, and has a turbine rotor and a compressor rotor attached to both sides of the shaft, a a ring-shaped protrusion that fits into a ring-shaped groove formed on the surface; and a turbine rotor side that comes into contact with a stepped portion of a holding member that holds a permanent magnet on the compressor rotor side of the housing and the magnetic thrust bearing. The inner peripheral side surface on the compressor rotor side is provided with a stepped part shaped to sink into the outer peripheral corner of the compressor rotor on the turbine rotor side, and a bearing is provided on the outer peripheral surface. A thrust bearing device for an air bearing type turbocharger, characterized in that a fixing member having a threaded portion that is screwed into a housing is provided.