GB2285100A - Sliding bearing - Google Patents

Description

2285100 This invention relates to sliding bearings incorporating pressure

pads.

The invention is particularly concerned with sliding bearings having pressure pads which are arranged in a ring and which each have a cylindrical pin which is set into a bore of a carrier and which is held against removal by at least one ring member, wherein the bore has a greater diameter than the pin and the pad is tiltably movable within the play space which is created by the difference in diameters.

The pressure pads of certain known sliding bearings are each provided with a cylindrical pin which is inserted into a bore of a carrier and which is secured therein by a spring ring or toothed ring set on the pin. Also, designs are known in which both a toothed ring and also a spring ring are provided, with the spring ring preventing the toothed ring from sliding off the pin. The bores prevent any undesired lateral positional displacement of the pressure pads.

The spring rings or toothed rings prevent the pressure pads from falling out of the bores during the assembly or dismantling of the sliding bearing. The toothed ring and/or the spring ring are set into a circumferential groove in the pin of the pressure pad.

The bores have a greater diameter than the pins, so that the pins and consequently the pressure pads are tiltably movable within the play space created by the difference in diameters. The tilting movement is necessary in order that a lubricating oil film or oil wedge can be formed between the contact surface of the pressure pads and a sliding surface of an opposing body supported by the pads, and to ensure that this oil film or wedge is maintained during use.

The pressure pads preferably have a circular cylindrical shape and a circular sliding surface.

Howeverr other shapes are possible. Circular cylindrical pressure pads have the advantage that they are independent of direction of rotation, so that the axial bearing which is thereby created can be used in both directions of rotation. The pressure pads are preferably supported on the carrier by means of a spring member, for example a cup spring. In this way all the pressure pads are loaded substantially equally in use, even in the event of manufacturing irregularities. The axial bearing formed by the pressure pads can be self-lubricatingr for example having oil bath lubrication or ring oiling, and/or can be provided with pressurised oil lubrication. The lubricating oil can be cooled and thus serve at the same time as a cooling medium. The bores which are formed in the carrier to receive the pins of the pressure pads can be through bores or blind bores.

The spring rings, also called snap rings, and the toothed rings can only be set onto the pins with some difficulty however. The greater the diameter, the more difficult it is to set these rings onto the pins of the pressure pads. There is the danger that the rings will be perma nently deformed into a wave shape in the circumferential direction when being set onto the pins due to their large expansion. The snap rings or toothed rings, particularly if they are severely deformed by being set onto the pins, make it difficult to insert the pins into the bores and they prevent the free tilting movement of the pressure pads during use, as a result of which the oil wedge formation between the pressure pads and an opposing member which is necessary to achieve sufficient lubrication is impaired. Snap rings or toothed rings which are very large in diameter cannot be set onto the pins, and instead a cylinder head screw must be screwed on to the 4 1 free end of each pin, which screw has a cap on which the snap ring or the toothed ring sits so as to be held between the cylinder head of the screw and the end face of the pin of the pressure pad.

It is an object of the present invention to simplify the assembly of the pressure pads in such a way that the assembly can be carried out more quickly and without special tools, and with the bearing function not being impaired regardless of the size of the pressure pads.

In accordance with the invention there is provided a sliding bearing with pressure pads which are arranged in a ring and which each have a cylindrical pin which is inserted into a bore in a carrier, the pin being held therein against falling out by at least one ring member set into the pin, in which the bore has a larger diameter than the pin and the pressure pads are each tiltably movable within the play space provided by the difference in diameters, and in which said at least one ring member is of an elastic yieldable rubber or rubber-like material.

Further features of the invention are set out in the subsidiary claims. It is particularly to be noted that in the case of bores which are designed as blind bores a passageway is provided which connects the bore sections which are divided by the ring member so that there is fluid communication therebetween. This passageway can be formed by a splitting of the ring or by a substantially axial bore or groove in the ring member. Such a flow passageway between the bore sections divided by the ring member can alternatively be made through the carrier of the pressure pads, although this is more expensive than providing a connecting recess or passage through the ring member itself.

The ring member according to the invention consists of an elastic yieldable material, which is rubber or rubber-like. Such a ring member can, in contrast to snap rings or toothed rings, be set in place on the pins of the pressure pads without special tools. Even with large diameters there is no deformation of these ring members which could cause adverse effects during the use of the pressure pads.

The ring member can be manufactured to any diametrical size, and in any diameter can be set on to a pin of a pressure pad in an equally simple manner.

It slides easily into the bore of the carrier without adversely affecting the free tilting movement of the pressure pad during use. The frictional grip of the ring member in the bore is sufficiently large to prevent the pressure pad falling out of the bore unintentionally during the assembly.

The invention will now be described in more detail with reference to an embodiment which is given by way of example and which is shown in the accompanying drawing. In the drawing:

Fig. 1 is a side view of a pressure pad which is inserted into a blind bore of a carrier, which itself is shown in section partially broken away, and which in accordance with the invention is provided with an 0-ring of rubber which holds the pressure pad in the blind bore; Fig. 2 is a schematic front-side view of the carrier, on a reduced scale, showing a plurality of pressure pads of the axial bearing of Fig. 1; Fig. 3 is a side view of the axial bearing of Figs. 1 and 2.

The axial sliding bearing in accordance with the invention which is shown in Figs. 1, 2 and 3 of the drawings essentially comprises a carrier ring 2, which 4 carries a plurality of pressure pads 4 and a pressure ring 6 which lies axially opposite the carrier ring and which has an annular contact surface 8 which contacts the circular contact faces 10 of the pressure pads 4 and which rotates relative to the carrier ring 2. oil film wedges are formed between the contact faces 10 of the pressure pads 4 and the contact face 8 of the pressure ring 6 as a result of tilting of the pressure pads 4, as is known.

Fig. 1 shows one of the pressure pads 4 on an enlarged scale as compared with Figs. 2 and 3. The pressure pad 4 is supported on the carrier ring 2 by means of a plate spring or cup spring 12. Thus, even in the event of irregular spacings of the contact surface 8 of the pressure ring 6 from the carrier ring 2, for example as a result of dimensional irregularities in the manufacture or uneven utilisation of material or even errors of alignment between the carrier ring 2 and the pressure ring 6, one still achieves an approximately equal pressure distribution on all pressure pads 4.

The pressure pads 4 are each provided with a pin 14 on which the plate spring 12 is seated, with each pin being inserted into a bore 16 in the carrier ring 2. The diameter of the bore 16 is greater than the diameter of the pin 14, so that the pressure pad 4 can perform tilting movements within the play space arising from the difference in diameters. The pin 14 can be formed integrally with the pressure pad head 17, which is provided on its face with the contact face 10, or alternatively can be secured to this pressure pad head 17. In a circumferential groove 18 of the pin 14 is seated an 0-ring 20 of rubber or a rubber-like elastic material, which projects beyond the diameter of the pin 14 in the unstressed condition but which is is compressed into the circumferential groove 18 by the wall of the bore 16 in the working position as shown in Fig. 1.

If the bore 16 is not a through-bore through the thickness of the carrier ring 2, but is a blind bore as shown in Fig. 1, then upon inserting the pin 14 into the bore 16 an air cushion is created which attempts to force the pin 14 out of the bore 16. In order that the air in this cushion can escape outwards, at least one passageway 22 is provided, which connects the sections 24 and 25 of the bore 16 which are separated from one another by the ring 20 for the flow of air therebetween. The passageway 22 can be formed as a hole or groove in the ring 20, or alternatively by a break interrupting the annular shape of the ring 20. The passageway 22 formed in the ring 20 is shown schematically in Fig. 1. The pressure pad 4 and its pin 14 are formed symmetrically in relation to the axis 26 of the bore and preferably each have a circular cylindrical shape.

The drawings illustrate an axial sliding bearing. The carrier ring 2 and the pressure ring 6 rotate relative to one another about a common bearing axis 28. In a modified embodiment of the invention the sliding bearing could alternatively be formed as a radial bearing.

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Claims (7)

CLAIMS:

1. A sliding bearing with pressure pads which are arranged in a ring and which each have a cylindrical pin which is inserted into a bore in a carrier, the pin being held therein against falling out by at least one ring member set into the pin, in which the bore has a larger diameter than the pin and the pressure pads are each tiltably movable within the play space provided by the difference in diameters, and in which said at least one ring member is of an elastic yieldable rubber or rubber-like material.

2. A sliding bearing according to claim 1, in which the or each ring member is a split ring.

3. A sliding bearing according to claim 1 or 2, in which the or each ring member is set in a circumferential groove in the pin and in the unstressed condition extends radially beyond the pin, but is arranged to be compressed into the circumferential groove by the wall of the bore when the pin is inserted into the bore.

4. A sliding bearing according to any preceding claim, in which at least one passageway is provided across the ring member which connects the bore sections which are separated from one another by the ring member for fluid communication therebetween.

5. A sliding bearing according to claim 4, in which said at least one passageway is formed in the ring member.

6. A sliding bearing according to any preceding claim, in which the bores are blind bores.

7. A sliding bearing substantially as hereinbefore described with reference to the accompanying drawing.