GB1576851A - Guiding arrangement for a caged roller bearing - Google Patents

Description

(54) A GUIDING ARRANGEMENT FOR A CAGED ROLLER BEARING (71) We, LINDE AxTIENGEsELLscHArrr, a German Company, of Abraham-Lincoln- Strasse 21, D-62 Wiesbaden, Federal Re public of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particu larly described in and by the following statement :- This invention relates to a machine hav ing a caged roller bearing between two machine parts, one of which is static and the other of which is angularly adjustable.

One example of such a machine is an ad justable switch-plate machine which, as is well-known, is a machine having a rotatable cylinder block, pistons being displaced along the cylinders by being connected to sliders which bear against a piston-guide surface which is inclined to the rotational axis of the cylinder block. The piston-guide surface is provided by the flat surface of a so-called rocker which is movable angularly about an axis which is perpendicular to the rotational axis of the cylinder block, and the piston stroke is adiusted bv altering the angle of porting parts. If, for example, relative movement between the static and moving parts in one direction is always made under load whereas relative movement in the opposite direction is made under no load, it is possible, after repeated relative movements, for the caged rollers to become displaced to a position in which part of the roller bearing is no longer able to perform its function. If this were to happen, the load supporting capacity of the bearing would be reduced. In order to prevent the caged rollers from wandering out of position in such a way, it is known for the cage to abut against a stop but, when moved in such a way, the centre of the loaded part of the roller bearing no longer stands on the line of action of the force. Apart from this load, a force is exerted on the cage by the stop and this other force, in extreme cases, causes the moving part to slide on the rollers with the result that on the one hand wear occurs and on the other high locating forces are necessary. Another result can be damage to the cage, thereby making the bearing unusable.

PATENTS ACT t949 SPECIFICATION NO 1576851 In pursuance of Section 8 of the Patents Act 1949, the Specification has been amended in the follwvinb manncr :- Page 2, line 11, page 3, line 60, delete and Page 2, line 15, page 3, line 64, after guide ; said guide comprising two substantially parallel limbs ; and each of said first and said second connecting elements extending between said parallel limbs ; Page 2, delcte lines 21 to 24 Page 3, delete lines 70 to 74 Page 3, for claims 3 to 8 read 2 to 7 Page 3, line 75, for 2 read 1 Page 3, lines 77 and 80, for 3 read Page 3, lines 85 and 95, for 3 to 5 rend 2 tu 4 THE PATENT OFFICE t ? nue 1981 Bas 83 273/1 (54) A GUIDING ARRANGEMENT FOR A CAGED ROLLER BEARING (71) We, LINDE AKTIENGESHLLSCHAFT, a German Company, of Abraham-Lincoln- Strasse 21, D-62 Wiesbaden, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particu larly described in and by the following statement :- This invention relates to a machine having a caged roller bearing between two machine parts, one of which is static and the other of which is angularly adjustable.

One example of such a machine is an adjustable switch-plate machine which, as is well-known, is a machine having a rotatable cylinder block, pistons being displaced along the cylinders by being connected to sliders which bear against a piston-guide surface which is inclined to the rotational axis of the cylinder block. The piston-guide surface is provided by the flat surface of a so-called rocker which is movable angularly about an axis which is perpendicular to the rotational axis of the cylinder block, and the piston stroke is adjusted by altering the angle of inclination of the piston-guide surface to said rotational axis. The rocker has a convex cylindrical surface whose axis of curvature is coincident with the axis about which said rocker is angularly movable, and a portion of the casing of said machine has a concave cylindrical surface whose curvature is complementary to the convex cylindrical surface of the rocker. It is known to use a caged roller bearing between said convex and concave cylindrical surfaces.

However, when the movable part is moved angularly about its swivel axis, a point on the cage of such a roller bearing does not travel exactly half the distance which is travelled by a corresponding point on the moving part (for example, on the rocker) relative to the static part (for example, the casing) because the periphery is greater on the static part than it is on the moving part.

However, the movement of the cage must be limited so that the rollers do not move out of the area between the two mutually supporting parts. If, for example, relative movement between the static and moving parts in one direction is always made under load whereas relative movement in the opposite direction is made under no load, it is possible, after repeated relative movements, for the caged rollers to become displaced to a position in which part of the roller bearing is no longer able to perform its function. If this were to happen, the load supporting capacity of the bearing would be reduced. In order to prevent the caged rollers from wandering out of position in such a way, it is known for the cage to abut against a stop but, when moved in such a way, the centre of the loaded part of the roller bearing no longer stands on the line of action of the force. Apart from this load, a force is exerted on the cage by the stop and this other force, in extreme cases, causes the moving part to slide on the rollers with the result that on the one hand wear occurs and on the other high locating forces are necessary. Another result can be damage to the cage, thereby making the bearing unusable.

It is also known for a cog meshing with teeth on each of the two bearing sections to be disposed on a pin located on the bearing cage. Here one of the two sets of teeth can be mounted so as to be displaceable longitudinally and braced against springs.

Thus, the use of a sprung element in conjunction with the cage return is basically known, but only in conjunction with a set of teeth. However, such a set of teeth is very expensive and either takes up a lot of space or is sensitive to wear (United States Patent Specification No, 3, 396,670).

The principal object of the present invention is to prevent, inexpensively, the cage with the rollers from slipping or falling out without also causing the troubles mentioned above, and to ensure permanent satisfactory operation with minimal expense and minimal wear.

Accordingly, the present invention consists in a machine having a member mounted in a static part of the machine by a bearing which permits said member to be adjusted angularly to a limited extent relative to said part about an adjustment axis, said bearing including rollers retained in an arcuate cage between a convex surface of revolution on said member and a concave surface of revolution on said part ; a guide pivotally connected at or near one end thereof to said part; a first connecting element attached to said member and engaging said guide at or near the other end thereof ; and a second connecting element attached to said cage and engaging said guide at a location intermediate said one and said other ends of said guide; whereby, during angular ad justment of the member relative to said part, said first connecting element moves said guide about its pivotal axis and thereby causes said guide to move both the second connecting element and the cage.

Preferably, said guide comprises two substantially parallel limbs, each of said first and said second connecting elements extending between said parallel limbs.

The two limbs may be elastic; moreover, said elastic limbs could be connected together elastically.

It has been found that a thoroughly feasible solution exists when the two limbs are rigidly connected together in such a manner that the second connecting element is guided between the two limbs with minimal play. If the cage tries to drift when the static and moving parts are moved relative to one another under high loading, the forces acting on the link are certainly relatively high as well but, because operational phases recur in which only relatively small forces act on said static and moving parts, the force is broken down in these operational phases so that, overall, the forces and stresses arising remain within reasonable bounds.

The limbs may be connected together at corresponding one ends thereof, the other end of one of the limbs being a free end and the other end of the other limb extending into, or being connected to a peg which extends into, a right cylindrical bore in said static part, thereby providing the pivotal connection between the guide and the static part.

Alternatively, the corresponding one ends and the corresponding other ends of the two parallel limbs may be connected together by bights to form a unit of closed configuration, a third connecting element being attached to said static part, all of said connecting elements extending between said parallel limbs.

The present invention will now be more particularly described with reference to the accompanying diagrammatic drawings, in which: Figure 1 illustrates, only by way of example of a machine according to the present invention, an angularly adjustable rocker of an adjustable swash-plate machine, viewed along the axis of rotation of said rocker; Figure 2 illustrates a detail view taken along the section line II-II in Figure I ; Figures 3 and 4 illustrate two other possible positions of the rocker illustrated in Figure 1 ; and Figure 5 shows, by way of example only, an alternative machine according to the present invention.

Referring to Figures 1 to 4, there is illustrated a portion of a casing 1 of an adjustable swash-plate machine, a rocker 2 being mounted for angular movements about an axis of rotation which is perpendicular to the surface of the drawing by means of a roller bearing which comprises a track 3 and rollers 4 whose proper spacing from one another is maintained by a cage 5. The rocker 2 has a convex cylindrical surface which rests directly on the rollers 4 which roll over the track 3 which is mounted on the casing 1.

The cage 5 carries a connecting element 6, a connecting element 7 is fixed to the rocker 2 and a connecting element 8 is fixed to the casing 1. Lastly, a guide 9, consisting of two parallel limbs which are joined to one another at their corresponding ends by arcuate bights to form a unit of closed configuration, is mounted pivotally on the connecting element 6.

As long as the three connecting elements 8,6,7 lie on a straight line, the limbs of the guide 9 do not exert any repositioning force on the connecting element 6. However, if the cage 5 were to tend to wander out of its required position, the connecting element 6 would also try to depart from the straight line joining the connecting elements 7 and 8, with the result that the guide 9 would exert a relocating force on the connecting element 6 and thus on the cage 5.

In an alternative form, a guide similar to the guide 9 can be mounted so as to be free to slide relative to the connecting element 6 instead of pivoting thereon; thus, said guide 9 is free to slide on all three pins 8, 6 and 7 and is mounted in a floating fashion. This has the disadvantage that the guide can move under vibration or inertia forces acting on the machine as a whole and that varying relocating forces are obtained depending on whether the guide projects beyond the connecting elemenuts 7 and 8 by the same amount at both ends or is moved out of this attitude.

Figure 3 shows the mechanism of Figure I after the rocker 2 has been swung in a clockwise direction relative to the centre position which is shown in Figure 1, and Figure 4 shows said mechanism after it has been swung in the opposite direction.

The exemplary alternative embodiment illustrated in Figure 5 differs from that shown in Figures 1 to 4 in that it comprises a guide 10 which is formed differently to the guide 9 and is mounted pivotally in the casing I. Said guide 10 has two parallel limbs but, instead of those limbs being so connected to one another as to form a unit of closed configuration, said two limbs are connected to one another only at corresponding one ends thereof. The other end of one of said two limbs is a free end and the other end of the other limb is either bent through 90 and inserted into a right-cylindrical hole in the casing 1 or connected to a peg which is inserted into a right-cylindrical hole in the casing 1. The reference numeral 18 indicates these two alternatives, each of which provides the pivot for the guide 10. A connecting element 16, which is connected to the cage 5, and a connecting element 17, which is connected to the rocker 2, extend and slide between the two parallel limbs of the guide 10.

It is pointed out that the guides 9 (Figures 1 to 4) and 10 (Figure 5) are made of a springy material which is such that, when the rocker 2 is adjusted to a second position thereof from a first position thereof, there might be a tendency for the pin 6 (Figures 1 to 4) or the connecting element 16 (Figure 5) to lag, with the result that the three pins 8,6,7 or the connections 18, 16, 17, respectively, would momentarily not be in a straight line. This temporary situation is soon altered because the relevant spingy limb of the guide 9 or of the guide 10 exerts the necessary relocating force on the pin 6 or connection 16.

Moreover, in addition to maintenance of the proper spacing of the rollers 4, the cage 5 in both illustrated embodiments acts to maintain the axes of the rollers 4 parallel to one another and also to axis of rotation of the rocker 2.

Claims (8)

1. WHAT WE CLAIM IS : 1. A machine having a member mounted in a static part of the machine by a bearing which permits said member to be adjusted angularly to a limited extent relative to said part about an adjustment axis, said bearing including rollers retained in an arcuate cage between a convex surface of revolution on said member and a concave surface of revolution on said part; a guide pivotally connected at or near one end thereof to said part; a first connecting element attached to said member and engaging said guide at or near the other end thereof; and a second connecting element attached to said cage and engaging said guide at a location intermediate said one and said other ends of said guide; whereby, during angular adjustment of the member relative to said part, said first connecting element moves said guide about its pivotal axis and thereby causes said guide to move both the second connecting element and the cage.
2. 2. A machine as claimed in Claim 1, wherein said guide comprises two substan tially parallel limbs and wherein each of said first and said second connecting elements extends between said parallel limbs.
3. 3. A machine as claimed in Claim 2, wherein the two limbs are elastic.
4. 4. A machine as claimed in Claim 3, wherein the two limbs are connected together elastically.
5. 5. A machine as claimed in Claim 3, wherein said limbs are connected together elastically at corresponding ends thereof by an elastic bight.
6. 6. A machine as claimed in any one of Claims 3 to 5, wherein the limbs are connected to one another at corresponding one ends thereof, the other end of one of the limbs being a free end and the other end of the other limb extending into or being connected to a peg which extends into a right cylindrical bore in said static part, thereby providing the pivotal connection between the guide and the static part.
7. 7. A machine as claimed in any one of Claims 3 to 5, wherein the corresponding one ends and the corresponding other ends of the two parallel limbs are connected together by bights to form a unit of closed configuration, and wherein a third connecting element is attached to said static part, all of said connecting elements extending between said parallel limbs.
8. 8. A machine having a member mounted in a static part of the machine by a bearing which permits said member to be adjusted angularly to a limited extent relative to said part about an adjustment axis, said machine being constructed, arranged and operable substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 4 or Figure 5 of the accompanying diagrammatic drawings.