DEVICE FOR SECURING AN ANTIFRICTION BEARING ELEMENT TO A SHAFT

Abstract: A device for securing a machine element (2) on a shaft (3) com­ prises a clamping sleeve (4) and a clamping member (6) coopera­ ting therewith, wherein the clamping sleeve (4) and the clamping member (6) have cooperating threads (5) or the like. The clamp­ ing sleeve (4) is made integral with the machine element (2) and formed as at least one axially extended sleeve-shaped portion (4) thereof. The sleeve-shaped portion (4) is adapted to bei radially contracted into engagement with the shaft (3) upon re­ lative rotation between the clamping member (6) and the clamping sleeve (4).

Description: The present invention relates to a device for securing the inner ring of a bearing having a raceway for a rolling element to a shaft having an axis and a peripheral surface defining a contact zone comprising at least one circumferentially extending continuous sleeve portion projecting axially from one end of the inner ring formed integrally therewith, said sleeve portion having external threads with flanks disposed at a predetermined angle to the axis of the shaft and disposed radially inwardly of said raceway, and a locking member having internal threads with flank angle complementing the external threads, wherein said locking member and inner ring have confronting engagable contact surfaces disposed at a common angle to the axis of the shaft. A device of this type is disclosed in US-A-4160608. Other devices for securing bearings to a shaft are disclosed in DE-B-1031060 and GB-A-1452216. In the device shown in DE-B-1031060 a separate clamping sleeve is used. Further, the clamping force is focused under the raceway. In the device shown in GB-A-1452216 two split sleeves are provided with cam surfaces cooperating with corresponding cam surfaces on sleeve portions on the inner ring of a bearing. When the split sleeves are axially moved in opposite directions the inner ring is clamped to the axis. When mounting a machine element, such as a bearing on a shaft it is possible to either mount the machine element directly upon the shaft by means of a press fit, a shrinkage fit or a glue joint or by means of a clamping sleeve having tapering grooves or threads. In the latter case the clamping force against the shaft is created mainly by an axial force against the machine element, e.g. effected by a nut, which is tightened along a threaded portion of the clamping sleeve against one end surface of the machine element. The clamping sleeve and the nut are manufactured and stored as individual and separate members, which results in high manufacturing costs and time-consuming mounting. The purpose of the present invention is to provide a device of the type mentioned above, which results in a less expensive manufacture and simplified mounting as compared to earlier known devices. This has been obtained by giving the invention the characterizing features stated in the claims following hereinafter. The invention will be described in detail with reference to various embodiments shown in the accompanying drawings, in which Figs. 1-3 show axial sections through different embodiments of the invention. It is to be understood that these embodiments are only illustrative of the invention and that various modifications thereof can be made within the scope of the claims. Fig. 1 shows a machine element in form of an inner race ring 2 of a ball bearing 1, which is mounted on a shaft 3. On opposite sides thereof, the inner race ring 2 is provided with axially extended sleeve-shaped portions 4 provided with external threads 5. The inner race ring 2 as well as the portions 4 associated therewith are made of solid material. A nut 6 is tightened on each one of the sleeve-shaped portions 4, which are slotted as illustrated by reference numeral 7, in order to obtain a clamping effect. Preferably, the thread 5 has a large pitch and the flank forms a comparatively small angle to the axis of the sleeve. When tightening the nut 6, the sleeve-shaped portion 4 due to wedge effect will be radially contracted under the nut 6 and it will be frictionally secured to the shaft 3. The increase in force, thus will mainly take place under the nut 6. Preferably, the contact surface 8 between the inner race ring 2 and the nut 6 has an oblique angle for achieving a wedging effect. According to the embodiment shown in Fig. 2 the inner race ring 2 with the associated slotted, sleeve-shaped portions 4 are made of pressed sheet metal. In Fig. 3 the inner race ring 2 and the sleeve-shaped portion 4 are made of pressed sheet metal embedded in polymeric material 9, whereby the threads 5 of the sleeve-shaped portions are formed by the polymeric material. In the illustrated embodiments a plastic nut is used, which is reinforced with a helical steel member.

Claims: A device for securing the inner ring (2) of a bearing having a raceway for a rolling element to a shaft (3) having an axis (A-A) and a peripheral surface defining a contact zone (3a) comprising at least one circumferentially extending continuous sleeve portion (4) projecting axially from one end of the inner ring formed integrally therewith, said sleeve portion (4) having external threads with flanks disposed radially inwardly of said raceway, and a locking member (6) having internal threads with flank angle complementing the external threads, wherein said locking member and inner ring have confronting engagable contact surfaces (8, 8′) disposed at a common angle to the axis (A-A) of the shaft, characterized in that the common angle of contact surfaces (8, 8′) is greater than the flank angle of said internal threads of said locking member (6) whereby said sleeve portion (4) is radially contracted to frictionally lock said contact zone (3a) relative to the bore surface (4a) upon further rotation of the locking member (6) from a point where said contact surfaces (8, 8 a ) engage, and further characterized in that the flanks of the internal and external threads of the sleeve portion and the locking member form a comparatively small angle to the axis of the sleeve such that a wedging effect is achieved. A device according to claim 1, wherein said sleeve-shaped portions (4) are slotted (7). A device according to claim 1 or 2, wherein the contact surface (8) between the inner ring (2) and the locking member (6) is tapering. A device according to any of the preceding claims, wherein the inner ring (2) and the sleeve-shaped portions (4) are made of pressed sheet metal. A device according to claim 4, wherein the sheet metal is embedded in polymeric material (9).

Inventors: ADOLFSSON, RUNE
Applicants: SKF NOVA AB
Application year: 1989
Main classification: F16C35
IPC codes: F16C35, F16C33