JPS6336029A - Piston for rotary piston internal combustion engine - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to an aluminum piston of a rotary piston internal combustion engine of the trochoidal construction type, in which a bearing bush with a hollow ring for synchronization 'Ml is arranged.

Such a piston has a particularly triangular profile and is intended to be inserted into a housing with a two-arc trochoidal outer cylindrical surface.

Such pistons have the advantage over pistons forged from steel or made from cast iron that they have a significantly lower mass and a better heat transfer. In such a machine,
The mass of the piston plays a significant role. This is because the piston has an eccentric circular motion that must be compensated for by counter and balance weights.

The good heat conduction of the aluminum piston has the advantage that the piston can be cooled through the sidewalls, thus reducing its internal cooling with oil or the combustion intensity indoors with the piston. bring. However, there are difficulties in achieving this benefit due to the different large thermal strains of steel and aluminum, especially due to the differential thermal expansion between the bearing bushing and the piston.

The aluminum piston requires the arrangement of such a steel bearing bush, which can at the same time be a carrier of the hollow shaft for the synchronizer. The relatively high thermal expansion of aluminum loosens the connection between the aluminum piston and the bearing bushing that exists in the cold state. Similar problems occur with screw joints between pistons and hollow shafts. There is a risk that, especially when the piston heats up under load, the connection between the aluminum piston and its bearing bush or hollow shaft loosens and that the hollow shaft then tears against the piston.

The object of the invention is to provide an aluminum-type piston of a rotary piston internal combustion engine with a connection between the bearing bush, the hollow shaft and the aluminum piston that remains the same and constant under any temperature conditions occurring during operation.

In order to solve this problem, according to the invention, the bearing bushing, which is pressed into the piston in the cold state, is provided with a radially peripheral gripping edge on the side of the piston, which edge is screwed into the piston. , and the screw can be arranged in a distance sleeve in the bore of the piston, such that the distance sleeve projects beyond the piston by the value of the thermal expansion of the piston in the area of the bore. According to the construction of the invention, there is a rigid radial connection between the bearing bush and the piston in the cold state, which transitions into an equally rigid axial connection when the piston loosens due to heating of the piston.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The drawing shows a partial axial section through a corner of a piston l according to the invention in the cold state. The axial and radial sealing members are designated 2 and 3. A bearing bush 4 is inserted into the piston 1 and has a hollow shaft 5 of the synchronizer on the right side of the drawing. On the opposite side of the piston 1 , a radially outwardly directed edge 6 is arranged on the bearing bush 4 for screwing the bearing bush 4 with the piston 1 . One of the fixing screws 8 is shown axially in the bore 7 through the piston, which is screwed into the edge 6. Hole 7 has a distance sleeve 9 around screw 8.
is placed, and the end of this distance sleeve is
One shear 1 under the head 10 of screw 8 on the right side of the drawing
1 , and its opposite end abuts against the edge 6 . In the cold state of the piston 1, as shown in the drawing, this piston is narrower than the length of the distance sleeve 9 by the value of its thermal expansion in the hot operating state in the area of the screw 8, so that the edge An annular gap is created between the part 6 and the piston 1.

In the cold state, the bearing bush 4 is pressed into the piston 1 in its seat. In hot conditions, the connection between the piston 1 and the distance sleeve 4 loosens, as does the connection of the distance sleeve 9 in its bore 7. However, at the same time and to the same extent, the annular gap 12 closes due to the constant compression produced via the washer 11 by the tension of the screw 8.

Therefore, in any operating state there is an axial or radial compression to couple the piston and the bearing bushing;
This compression prevents the hollow shaft 5 from tearing against the piston 1. Screw 8 inside distance sleeve 9
This play makes it possible to absorb any radial extension of the piston relative to the edge of the bearing bush.

[Brief explanation of drawings]

The drawing is a partial axial sectional view of a corner of a piston according to the invention. ■... Piston 4... Support bushing 5... Hollow shaft 6... Edge 7... Hole 8... Screw 9... Destance sleeve

Claims (1)

[Claims] (1) In an aluminum piston of a rotating piston internal combustion engine of the trochoidal design, in which a bearing bush with a hollow ring for a synchronizer is arranged, the bearing bush (4 ) is radially arranged with an edge (6) gripping the piston (1) laterally and circumferentially, which edge is secured to the piston (1) by means of a screw (8).
, said screw is arranged in a distance sleeve (9) in the hole (7) of the piston (1), the distance sleeve (9) being connected to the heat of the piston (1) in the area of the hole (7). A piston characterized in that it projects beyond the piston (1) by the value of the expansion.