ARRANGEMENT FOR REDUCING PLAY IN A BALL JOINT

Abstract: Arrangement at a ball joint (1) of preferably manoeuvre organs, which extends through the ball joint. The manoeuvre organ comprises a bearing ball (22), which abuts against and is maintained in a certain position of a bearing bush (6), which is a part of the ball joint. The bearing bush comprises in its turn two bearing surfaces turned towards each other. The first and the second part of the bearing bush embrace to some extent the ball (22). The second part of the bearing bush is turnable in relation to the first part, whereas the second part comprises elements (13-15) adapted to cooperate with organs (9) on the bearing bush for controlling the distance between the first and the second part (5, 6) by means of turning the first part in relation to the second part.

Description: Title: Arrangement for Reducing Play In a Ball Joint. Technical field: The present invention relates to an arrangement at ball joints and, preferably, manoeuvre organs according to the preamble of the following claim 1. Prior art: Ball joints for, for example, gear control are well known. A known problem at these is that very small tolerances are required between the ball and the bearing bush of the ball joint of the gear control in which the ball is located. Great tolerances make the gear control feel loose and inexact to handle. Therefore a rigid and distinct bearing of the gear control is strived at. Attempts for high precision made up to now have resulted in a great cassation of material and required extended visual examination, which in its turn leads to increased production costs. Technical problem: Even if a high precision is attained at the production, wearing will arise due to the vibration which occurs in the gear control and is transferred to the bearing ball and the bearing bush, which gives rise to noise and a feeling of incomplete control over the positions of the gear control. The object of the present invention is to bring about an arrangement at ball joint which solve the above-mentioned problems. Solution: Said object is obtained by means of an arrangement accor¬ ding to the characterizing part of the following claim 1. Brief description of drawings: The invention will in the following be described more in detail by means of an embodiment example with reference to the attached drawings, on which Fig. 1 shows the arrangement in a section at a ball joint along the line A-A in Fig. 2, Fig. 2 shows the ball joint seen from above, Fig. 3 shows a part of the arrangement at the ball joint, and Fig. 4 shows a view of the part in Fig. 3. Best mode of carrying out the invention: As is shown in Fig. 1 and 2, the arrangement according to the invention includes a ball joint 1 which has been mounted in a housing 2. The ball joint 1 comprises a bearing bush 4 with a cavity extending through the bear- ing bush. The bearing bush comprises a first part 5 and a second part 6, both with bearing surfaces shown only in section in the drawings. The first part 5 is integrated with a cylindrical mounting 7 and it comprises a substan¬ tially circular opening 29. Tongues 8, in the shape of hooks, extend from the mounting part 7 and they are adapted to snap against a notch 11 on the housing 2. The housing 2 is in its turn rigidly connected to a vehicle chassis not shown in the drawings. The second bearing bush part 6 has been arranged in the mounting part 7 of the part 4 and has the shape of a ring as is shown in the Fig. 3 and 4. The ring has a circular opening 35 corresponding to the opening 29 in the first part 5. From the edge part 12 of the ring, moveable engagement organs in the shape of three cut off flanges 13-15, extent directed radially outwards and hinged along the periphery of the ring at some distance from each other so that openings 16 are formed between the flanges. The flanges 13-15 have a certain pitch along the edge part of the ring, which pitch is lower than 10%, and preferably lower than 7%. As best appears from Fig. 3, each flange part 13-15 gets, by means of its pitch, a lower end part 30 and one upper flange part 31 on a somewhat higher level, which together delimit the openings 16. At the lower end part 13, the flanges have no pitch which in the example shown is the case also at the upper flange part of the flanges. The upwardly turned part of the flanges from the bearing bush part 5 forms engagement surfaces for engagement with the fixed engage¬ ment organs in part 5, which will be described more in detail below. Said engagement surfaces consist for each flange of an oblique surface part 32, which forms the above-mentioned pitch by accordingly deviating from a radial plane through the ball joint, whereas the flanges at their end parts show mutually parallel surface parties 33,34 located in separate radial planes through the ball joint. A hook 17 has been arranged in one of these open¬ ings and adapted to keep one end of a tension spring in the shape of a helical spring 19. A number of notches 18 are arranged along the edge part of the ring to maintain the spring 19 in its position, which is arranged to be stretched along a part of the circumference of the ring. A long, pipe- or rod-shaped handle 21 is arranged through the ball joint through a cylindrical hole 25 in the ball 22, which is part of the ball joint and is adapted to abut between the first bush part 5 and the second bush part 6. The bearing ball 22 is axially stationary with regard to the handle, and in the example shown also non- turnable relative to this by means of locking rings 23,24. The bearing ball 22 has a spherical convex bearing surface 26, which can be a complete surface or composed of a plurality of part surfaces with spherical shape. Bearing surfaces 27,28 of the parts 5,6 are concave ring- shaped spherical zones with a radius corresponding to the one of the bearing surface of the ball. The mounting part 7 has on its inner barrel-shaped sur¬ face a number of rigid engagement organs in the shape of wings 9 with a peripheral extension which is shorter than the extension of the openings 16 and which preferably have some pitch which substantially corresponds to the pitch of the flanges 13-15 in the second bush part 6. The number of engagement organs correspond to the number of flanges 13-15. An attachment organ 10 for attachment of the second end of the spring 19, has been arranged on the mounting part 1 , preferably on one of the wings 9. Through the construction of the ball joint its mounting may occur in a simple and rational way. The bearing ball 22 is mounted on the gear control 21 in a predetermined position at which the ball is located by means of locking rings 23,24. Thereafter, the gear control 21 is inserted through the opening 29 of the first bush part 5 and mounting part 7 of the bearing part 4, until the ball abuts with a part of its bearing surface 26 against the bearing surface 27 of the first bush part 5, whereafter the second bush part is fed over the gear control 21 against the ball 22. During mounting, one has to observe that the second bush part 6 is turned so that the openings 6 will register with the wings 9 so that the bush part can be fed past the same whereby the openings allow the wings to pass them, and the second bush part can be moved down in a direction towards the first bush part 5 until abutment with its bearing surface 28 against the bearing surface 26 of the bearing ball 22. Thereafter, the second part 6 is turned around the axis of the ball joint so that the flanges 13-15, that is, the moveable engagement organs, will come into engagement with the wings, that is, the stationary engagement organs and the bush parts will be pressed towards its other end with their bearing surfaces 27,28 against the bearing surface 26 on the bearing ball 22. The second bush part 6 serves, consequently, as a nut where the flanges 13-15 form the threads of the nut in engagement with threads of the screw, which are formed by the wings 9 in the first bush part 5. Thereafter the spring 19 is attached with its end at the hook 17 on the second bush part 6 and is threaded around the edge part 12 of the bush part below the notches 18 in the turning direction for the mounting of the bush parts. The second end of the spring 19 is attached to the attachment means 10 on the mounting part 7 so that the second bush part by means of the spring force will strive at continuously being drawn in a direction towards the first bush part 5. This means that even if the bearing ball is worn, it will be maintained in a distinct position as the second bush part 6 continuously is subjected to a turning moment and strives at being drawn against the ball. Due to the small pitch of the flanges 13-15, a small spring force is re¬ quired to give a well adapted small, axially directed force of the first bush part 5 in the direction against the ball, and hence give a zero play against the ball and bearing surfaces of the bush parts, whereas an appreci¬ ably greater axial counter force is required to separate the bush parts. As low initial forces are working on the ball through its mounting in the bush parts 5 and 6, self-lubricating materials may be used in the ball joint, such as nylon, acetal- or polyester plastics, which give rise to a low friction. The invention is not limited to the above described and the embodiment example shown in the example, but can be varied within the scope of the following claims. For example, the stationary engagement organs 9 may be without pitch. Further the flanges may show a pitch over its whole length.

Claims: Claims: 1. Arrangement at ball joints (1) with, preferably, manoeuvre organs (21) , which extend through the ball joints, which comprises a bearing ball (22) abutting against and being maintained in a certain position of a ball joint comprising a bearing bush (4) which, in its turn, comprises at least two parts (5,6), c h a r a c¬ t e r i z e d in that the bearing bush (4) comprises a first part (5) , in which a first bearing surface (27) is arranged and a second part (6) , in which a second bearing surface (22) , turned towards the first bearing surface has been arranged, that the first and the second parts (5,6) embrace to some extent the bearing ball (22), that the second part (6) is turnable in relation to the first part (5) , that the second part (6) comprises elements (13-15) , adapted to cooperate with organs (9) at the bearing bush (4) for controlling the distance between the first and the second part (5,6) by means of turning of the first part (5) in relation to the second part (6) . 2. Arrangement according to claim 1, c h a r a c¬ t e r i z e d in that the second part (6) of the bearing bush (4) consists of a ring (6) , comprising protruding first engagement organs (13-15) from the edge part of the ring, being adapted to cooperate with the second engage¬ ment organs (9) at the bearing bush (4) so that a con¬ tinuous turning moment, being applied on the ring, gives the ring a force working in the direction towards the bearing ball. 3. Arrangement according to claim 2, c h a r a c ¬ t e r i z e d in that the protruding first engagement organs (13-15) on the ring (6) are oblique in relation to the turning plane of the ring. 4. Arrangement according to claim 3, c h a r a c ¬ t e r i z e d in that said first engagement organs con¬ sist of at least two, preferably, three, protruding ele¬ ments (13-15) , the pitch of which in relation to said turning plane is less than 10%. 5. Arrangement according to claims 1 and 2, c h a¬ r a c t e r i z e d in that the ring (6) is kept in a stretched position against the ball (26) by means of a stretching organ (19) which is maintained through the continuous turning moment. 6. Arrangement according to claim 5, c h a r a c ¬ t e r i z e d in that said stretching organ (19) con- sists of a spring.

Inventors: SKOGWARD KENNETH, SKOGWARD, KENNETH
Applicants: SCANDMEC MECANIA AB
Application year: 1990
Main classification: F16C11
IPC codes: F16C11