Ball bearing, in particular piston rod ball bearing and piston rod with ball bearing

Abstract

A ball bearing including a ball head arranged at a support rod and supported in a ball head receiver, characterized in that the ball head is secured at an outer surface of the ball head in the ball head receiver by a retaining ring against sliding out of the ball head receiver. The invention also relates to a piston rod with the ball bearing.

Claims

1. A connecting rod for a variable compression ratio internal combustion engine, comprising: an upper piston rod bearing located on an upper end of the connecting rod, wherein the upper piston rod bearing is connected to a plurality of actuation pistons to adjust an effective length of the connecting rod by actuating the upper piston rod bearing into different angular positions due to reciprocation of the plurality of actuation pistons, wherein the actuation pistons each include a ball bearing that provides a ball head arranged at a lower end of the actuation pistons and supported in a ball head receiver, wherein the ball head is secured at an outer surface of the ball head in the ball head receiver by a retaining ring against sliding out of the ball head receiver, wherein the ball head receiver includes an undercut integrally provided with the ball head receiver in one piece at an open end of the ball head receiver, wherein the undercut secures the retaining ring in the ball head receiver in an axial direction of the ball head receiver, wherein the ball head receiver includes a cambered base portion which is adjoined by a cylindrical cavity in the axial direction of the ball head receiver, wherein the retaining ring is applied against a wall of the cylindrical cavity with a preload, wherein the retaining ring has shoulder that is oriented radially inward with respect to the ball head at a face of the retaining ring oriented towards the ball head in an installed condition of the retaining ring, and wherein the retaining ring includes a convex camber oriented in a radially inward direction of the retaining ring.

2. The connecting rod according to claim 1, wherein the retaining ring is interrupted at its circumference.

3. The connecting rod according to claim 1, wherein the retaining ring is made from plastic material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional advantages can be derived from the subsequent drawing description. The drawings illustrate embodiments of the invention, The drawings, the description and the claims include several features in combination. A person skilled in the art will advantageously view the features individually and will combine them to form useful additional combinations, wherein:

(2) FIG. 1 illustrates a longitudinal sectional view of a piston rod with two ball bearings that is known in the art;

(3) FIG. 2 illustrates a first embodiment of a ball bearing according to an embodiment of the invention; and

(4) FIG. 3 illustrates another embodiment of a ball bearing according to an embodiment of the invention,

DETAILED DESCRIPTION OF THE INVENTION

(5) Identical or equivalent components are designated with identical reference numerals in the drawing figures. The figures illustrate exemplary embodiments and do not limit the spirit and scope of the invention.

(6) The known piston rod 100s illustrated in FIG. 1 includes an upper piston rod bearing eye 12s which is provided for receiving a non illustrated piston pin. This piston pin is typically inserted with a press fit into a combustion cavity piston of an internal combustion engine. The upper piston rod eye 12s is separated from the lower large piston rod bearing eye by a connecting rod.

(7) The upper piston rod bearing eye 12s is pivotable about a pivot axis by a bearing element that is configured as an eccentrical element wherein the pivot axis is arranged parallel offset to a longitudinal axis of the upper piston rod bearing eye 12s. For this purpose the eccentrical element is inserted into an opening of a lever 16s. Thus, it is possible to adjust the upper piston rod bearing eye 12s with respect to its distance from a piston rod bearing axis of the lower piston rod bearing eye in the figure and to implement a variable compression ratio in the combustion chamber of the internal combustion engine through the actuation pistons 18s supported at the upper piston rod bearing eye 12s. For this purpose the actuation pistons 18s are supported with a ball bearing 10s in receivers and bolted down at this location with transversal bolts. The actuation pistons 18s are loaded with a hydraulic pressure that acts in the hydraulic cavities that interact with the actuation pistons 18s.

(8) FIG. 2 illustrates a first embodiment of a ball bearing 10 according to an embodiment of the invention. The ball bearing 10 includes a ball head 20 arranged at a support rod 18 which ball head is supported in a ball head receiver 30 of an outer component 40. The ball head 20 is secured at its outer surface in the ball head receiver 30 by a retaining ring 50 against sliding out of the ball head receiver 30.

(9) The ball head receiver 30 includes a cambered base element 32 which is adapted to the outer contour of the ball head 20 and on which the ball head 20 can slide in order to facilitate a tilting of the support rod 18. In an axial direction towards an open end of the ball head receiver 30 a cylindrical space 34 adjoins in which the retaining ring 50 is arranged.

(10) The ball head receiver 30 includes an undercut 36 at its open end, wherein the undercut secures the retaining ring 50 in the ball head receiver 30 in the axial direction. This provides a high level of safety against the retaining ring 50 sliding out or being pulled out and thus the ball head 20 being pulled out the ball head receiver 30.

(11) The retaining ring 50 is applied with a preload against a wall 38 of the ball head receiver 30. Thus, the retaining ring 50 is slotted and can be compressed for assembly and insertion into the ball head receiver 30. Furthermore the slotted retaining ring 50 can be pushed over the support rod 18 in a simple manner.

(12) The retaining ring 50 is configured e.g. as a sheet metal component and includes a radially inward oriented shoulder 52 at its face oriented towards the ball head 20 in the installed condition, wherein the shoulder 52 limits an axial movement of the ball head 20. Simultaneously the ball head can slide on the shoulder 52 with its outer surface when being tilted.

(13) FIG. 3 illustrates another embodiment of a ball bearing 10 according to an embodiment of the invention. The ball bearing 10 includes a ball head 20 that is arranged at a support rod 18, wherein the ball head 20 is supported in a ball head receiver 30 of an external component 40. The ball head 20 is secured at its outer surface in the ball head receiver 30 through a retaining ring 50 against sliding out of the ball head receiver 30.

(14) The ball head receiver 30 includes a cambered base element 32 which is adapted to the outer contour of the ball head 20 and on which the ball head 20 can slide in order to facilitate tilting of the support rod 18. A cylindrical space 34 adjoins in an axial direction towards an open end of the ball head receiver 30 wherein the retaining ring 50 is arranged in the cylindrical space 34.

(15) The ball head receiver 30 includes an undercut 36 at its open end wherein the undercut axially secures the retaining ring 50 in the ball head receiver 30. This provides a high level of safety for the retaining ring 50 against sliding out or being pulled out and thus the ball head 20 being pulled out of the ball head receiver 30.

(16) The retaining ring 50 is thus applied with a preload against a wall 38 of the ball head receiver 30. Thus, the retaining ring 50 is slotted and can be compressed for assembly purposes and can be inserted into the ball head receiver 30. Furthermore the slotted retaining ring 50 can be pushed over the support rod 18 in a simple manner.

(17) The retaining ring 50 is made e.g. from plastic material and includes a radially inward oriented camber 54 at its face that is oriented towards the ball head 20 in the installed condition, wherein the camber limits an axial movement of the ball head 20. Simultaneously the ball head can slide on the camber 54 with the outer surface of the ball head when being tilted.

(18) The ball bearing 10 is advantageously used for supporting the support rod 18 of a piston rod 100 which is for example used in an internal combustion engine with an adjustable compression ratio wherein the piston rod 100 as described supra can include devices for adjusting an effective piston rod length. Also under high load the ball head 20 of the ball bearing 10 is securely supported in the ball head receiver 30.