WO2004083660A1

WO2004083660A1 - Ball joint device

Info

Publication number: WO2004083660A1
Application number: PCT/NO2004/000073
Authority: WO
Inventors: Sven BJØRKGÅRD; Tor Erling Ruud
Original assignee: Kongsberg Automotive Asa
Priority date: 2003-03-18
Filing date: 2004-03-18
Publication date: 2004-09-30
Also published as: NO20031250D0; NO20031250L

Abstract

A ball joint device with a first and a second ball joint part (1 and 2 respectively). In a housing (3) of the first ball joint part (1) there is provided a bore (10) which extends from an opening (11) of the bore (10) to a shoulder (14) facing the opening (11). In the bore (10) is inserted an outer bearing bush (15) with a radially inner, concave ball surface (17), a first end (18) which abuts against the shoulder (14), and an opposite second end (19) of the bearing bush (15). The second ball joint part (2) has a ball portion (31) with a radially outer surface (32) which can slide in the outer bearing bush (15). According to the invention the device comprises a retaining ring (36), which is arranged to be attached to the housing (3) round the opening (11) and to secure the outer bearing bush (15) in the correct axial position relative to the housing (3).

Description

Ball joint device

The invention relates to a ball joint device as indicated in the introduction to claim 1.

From the applicant's NO 308963 a V-shaped rod is known with two arms extending towards each other and securely interconnected by a connecting portion, where the rod's two free ends are connected to the chassis of a vehicle, and the connecting portion comprises the first ball joint part. The second ball joint part has a flange which is arranged to be attached to a wheel axle housing of the vehicle. With this device, however, the shoulder is provided near the opening of the bore and faces away from the opening. The bore must therefore have a second opening at its second end via which the outer bearing bush of the first ball bearing part and a mounting ring for this can be inserted. The bore must therefore be through-going.

Normally the first opening faces downwards and the second opening upwards. In order to prevent penetration of water and dirt via the second opening, it is sealed by means of a cap. In order to prevent such penetration via the first opening, a bellows is pulled on to the second ball joint part, the end edge areas of which bellows are inserted in respective grooves of the housing of the first ball bearing part and in the second ball bearing part. This cap, however, may be exposed to mechanical stresses from any falling objects such as tools etc. and the cap may thereby be damaged so that it no longer prevents penetration of water and dirt. Furthermore, portions of the bellows protrude outside the ball joint parts, with the result that it too can easily be damaged.

DE 44 20 489 discloses a device of the type mentioned in the introduction, where a first end area of a tubular bellows which is pulled on to the second ball joint part extends into a groove in the bore wall and abuts against the second end of the outer bearing bush. The outer bearing bush is thereby secured axially by being mounted between the shoulder and the bellows. Since the bellows material is elastic, there will be a relatively great risk of the bellows inadvertently being brought out of the groove by being influenced by an object, with the result that the outer bearing bush may fall out of the bore. This means there will no longer by any connection between the vehicle's chassis and the wheel axle housing, which may result in loss of ability to steer the vehicle.

The second end area of the bellows abuts against a smooth area of the pin.

On account of the weak connection between the bellows and the ball joint parts, there may be a risk of water flowing past the bellows' end areas into the bore, e.g. during cleaning of the vehicle by means of water under high pressure. In this case too the bore is through-going, and its second end is sealed by means of a small cap, with the resultant drawbacks mentioned above. Moreover, the small window for the cap is not very suitable for inserting a tool for pressing out an outer bearing bush via the opening if the outer cylindrical surfaces of the outer bearing bush and the bore have mutual press fit.

The object of the invention is to provide a device of the above-mentioned type which is not encumbered by the above-mentioned disadvantages.

The characteristic of the device will be apparent from the characterising features indicated in the claims. The invention will now be described in greater detail with reference to the drawings, in which:

Figure 1 illustrates a longitudinal section through a ball joint with a first embodiment of a device according to the invention, a portion of a ball joint part having been cut away. Figure 2 illustrates a detailed section of a longitudinal section corresponding to that illustrated in figure 1 , but where the attachment of the retaining ring is illustrated according to a second embodiment of the invention.

In the description below the term "up" in connection with the figure should be understood to refer to the direction towards the edge of the drawing facing away from the reader. Components of the ball joint which face upwards in the drawing will therefore also face upwards in the case of a ball joint mounted in a vehicle.

As can be seen in figure 1, the ball joint comprises a first ball joint part 1 and a second ball joint part 2.

The first ball joint part 1 may be provided in one end portion 3 of a rod 4, whose second end portion (not shown) is connected to a chassis (not shown) of a vehicle.

The second ball joint part 2 comprises a connecting portion 5 such as a flange, whereby the second ball joint part 2 can be securely connected to a wheel axle housing 6 of the vehicle, for example by means of screws which are indicated only by their longitudinal axis 7 or the like (not shown). The flange 5 extends in a flange plane 9.

In the first ball joint part 1 there is provided a blind bore 10, at the bottom of which is an opening 11. The end portion 3 of the rod 4 thereby forms a downwardly open housing of the first ball joint part 1 and will hereinafter be called housing. The bore 10 has a longitudinal axis 12 and comprises a cylindrical portion 13 which is terminated at the top by a radially inwardly extending shoulder 14. In the bore 10 is inserted an outer bearing bush 22 with a cylindrical, radially outer surface 16, a radially inner surface 17 in the form of a concave ball belt, a first, upper end 18, which abuts against the shoulder 14, and a lower end 19, which is located near the opening 11 but slightly above a lower surface 20 of the housing 3. Near the opening 11 and along its circumference, in the lower surface 20 of the housing, there may be provided a recess with an upper surface 21 which is aligned with the lower end 19 of the outer bearing bush 15.

The second ball joint part 2 comprises a cylindrical pin 30 extending perpendicularly to the flange plane 9 and into the bore 10 of the first ball joint part 1. The pin 30 has a ball portion, e.g. in the form of an inner bearing bush 31 with a convex, radially outer surface 32 which is complementary relative to the radially inner surface 17 of the outer bearing bush 15, and which is securely connected to the pin 30, for example in a manner described in the above-mentioned patent NO 308963. The inner bearing bush 31 abuts slidingly against the outer bearing bush 15 in such a manner that the ball joint parts 1 and 2 can be rotated and tilted relative to each other.

In figure 1 it can be seen that through the housing 3 and radially outside the bore 10 there are provided a plurality of holes 33, e.g. three holes 33, extending parallel to the bore's longitudinal axis 12. At least one of these holes 33 is located at such a distance from the longitudinal axis 12 and has such a large diameter that in the area of the outer bearing bush 15 they communicate with the bore 10. In each hole a screw 34 is inserted which is screwed into corresponding threaded holes 35 in a retaining ring 36. The retaining ring 36 extends round the opening 10 and protrudes a short distance radially into it. The retaining ring 36 is further arranged to be lifted up and come into forceful abutment against the lower surface 20 of the housing 3 by tightening the screws 34, while at the same time it may be mounted near the lower end 19 of the outer bearing bush 15, with the result that the bearing bush 15 is placed in the correct, axial position relative to the housing 3. For this purpose these components may have suitable relative fit.

A tubular bellows 40 is pulled on to the pin 30. The bellows 40 has a first end portion with a first, circumferential edge area 42 which is arranged to extend sealingly between the second end 19 of the outer bearing bush 15 and the retaining ring 36, this edge area 42 being compressed between them by tightening the screws 34. The outer bearing bush 15 is hereby pushed elastically upwards until it abuts against the shoulder 14 of the housing 3, with the result that this bearing bush 15 is placed in the correct position relative to the housing 3. A second edge area 43 of a second end portion 44 of the bellows 40 is arranged to extend sealingly round the pin by being pressed against the pin 30 by means of a clamping ring 45 which may be provided in the form of a hose clip. Alternatively, the clamping ring may be in the form of a continuous circumferential or endless ring, which is arranged to be pushed downwards on to an upwardly tapered, conical portion of the pin 30, e.g. by means of the inner bearing bush 31 when it is mounted on the pin 30, the second end area 43 of the bellows hereby being compressed. A person skilled in the art will understand that the bellows' second end area 43 may also be attached in another way. In order to prevent water and dirt from penetrating the bore 10 via the screw-holes 33, a gasket (not shown) may be mounted between the upper end 18 of the bearing bush 15 and the shoulder 14.

If the outer bearing bush 15 requires to be removed from the housing 3, the screws 34 are first released from the retaining ring 35 and removed from the holes 33. The retaining ring thereby remains located on the flange 5 and the first edge area 42 of the bellows 40 is released. A leg of, e.g. a hydraulic or pneumatic tool (not shown) can then be inserted in the hole 33 that communicates with the bore 10, the leg coming into abutment against a portion of the upper end 18 of the bearing bush 15 that protrudes into the hole 33, whereupon the tool pushes the outer bearing bush 15 downwards in the bore 10 and out of it. If several holes that communicate with the bore 10 are provided in the housing 3 instead of only one such hole, the tool may have a corresponding number of legs which are arranged for insertion in the respective holes.

In figure 2 the retaining ring 36 is illustrated attached to the housing 3 by means of a mounting ring 50. The mounting ring 50 extends in a direction which is substantially parallel to the retaining ring's 36 circumferential direction. A first portion 51 of the mounting ring 50 is fixed to the housing 3, for example as illustrated in figure 2, by the first portion 51 being attached to an edge area 55 of the housing 3. A second portion 52 of the mounting ring 50 is connected to the retaining ring 36. The second portion 52 of the mounting ring 50, preferably the outermost portion 52' of the second portion 52, may be arranged to secure the first edge area 41 of the bellows sealingly to the retaining ring 36, as illustrated in figure 2. By means of this arrangement the object is achieved that the mounting ring 50 ensures that the retaining ring 36 keeps the outer bearing bush 15 in the correct axial position relative to the housing 3, while at the same time the mounting ring's second portion 52 presses the bellows' first edge area 41 against the retaining ring 36 in order thereby to provide an adequate seal between the bellows 40 and the retaining ring 36.

In the embodiment illustrated in figure 2 the mounting ring 50 is provided with a groove 53 suitable for receiving the first edge area 41 of the bellows. The groove 53 preferably extends in the circumferential direction of the retaining ring's outer portion 54. The design of the groove 53 helps to ensure a seal between the edge area 41 and the retaining ring 36 by the mounting ring's outermost portion 52' pressing the edge area 41 into the groove 53. Continuous abutment surfaces are thereby obtained.

In figure 2 it can be seen that the retaining ring's 50 inner portion 56 may be provided with an inclined surface 57 extending in the retaining ring's 36 circumferential direction. The inclined surface 54 is designed so as to provide a clearance between the inclined surface 57 and the ball portion 31.

Figures 1 and 2 illustrate a section through the ball joint that coincides with the vehicle's longitudinal direction. The inclined surface 57 illustrated in figure 2 may vary in design and/or extent in different portions along the retaining ring's 36 circumferential direction. The retaining ring 36 may be designed in those portions that substantially coincide with the vehicle's transverse direction, where further extra material is added in order to extend the inclined surface 57 downwardly in the direction of the flange pin 30, in such a manner as to ensure that the ball portion 31 is kept in the bearing path even though the bearing becomes worn. (There is no figure to illustrate this, but a section along the longitudinal axis 12 in figure 1 coincides with a section in the vehicle's transverse direction). In these said portions along the retaining ring's 36 circumferential direction, the inclined surface 57 can therefore be arranged with a further extra area extending downwardly in an extension of the inclined surface 57. The extra area is preferably oriented substantially parallel to the ball portion's surface 32, the distance or clearance between the extra area and the ball portion's surface 32 being kept substantially similar to the clearance between the inclined surface 57 and the ball portion's surface 32. The clearance between the inclined surface 57 and the ball portion's surface 32 is kept substantially similar as illustrated in figure 2. Since it is necessary to allow for a larger angular deflection in the bearing in the vehicle's longitudinal direction due to the geometry of the wheel suspension, it is not realistic to extend the inclined surface 57 in those portions of the retaining ring 36 that substantially coincide with the vehicle's longitudinal direction. When the retaining ring 36 is designed as described here, the bearing's possible angular deflection in the vehicle's transverse direction will be reduced compared to the angular deflection in the vehicle's longitudinal direction. As a person skilled in the art will appreciate, it is also possible to provide different angular deflections in two perpendicular directions (for example transverse direction and longitudinal direction) in the ball joint in other ways than by designing the retaining ring 36 with varying cross sections. This can be solved in different ways, the crucial factor here being that the function of different angular deflections is provided in two perpendicular directions, and not the means by which this is achieved.

In accordance with the second embodiment of the invention the ball joint may also be provided with holes which communicate with the bore 10. The holes will advantageously be employed when dismantling the outer bearing bush 15 from the housing 3, as is also described in connection with the first embodiment of the ball joint. In the second embodiment of the ball joint, however, it is not necessary to make the holes through-going in the housing 3. The holes are positioned in the housing preferably extending down to the shoulder 14, with the result that the tool that is placed in the holes obtains sufficient contact with an upper end 18 of the outer bearing bush 15 in order to push the bearing bush 15 downwards and out of the bore 10. When the holes are not in use, they are sealed by a sealant which can easily be removed for dismantling the bearing bush. With the device according to the invention it will be ensured that the bellows' edge areas 42, 43 are forcefully secured against the housing 3 and the pin 30 respectively, thus preventing any risk of their being inadvertently removed from these parts.

Furthermore, the outer bearing bush is securely fixed to the housing 3, thus preventing any risk of it falling out and causing the loss of the ability to steer the vehicle.

In addition the housing 3 is closed at the top, thus preventing dirt and water from penetrating the bore 10 from above.

The advantage of the embodiment illustrated in figure 2 is that the housing and the retaining ring can be easily machined by turning. In the first embodiment of the invention, holes (in some cases as many as three holes) have to be made which also have to be threaded. The holes in the housing which partly go down into the housing bore also make it difficult to machine the house's bore 10 by turning. The holes are drilled first and will form jump cuts during the subsequent machine turning of the bore 10, which will result in knocking at the transition between the bore 10 and the holes.

Claims

1. A ball joint device with a first and a second ball joint part (1 and 2 respectively) where in a housing (3) of the first ball joint part (1) there is provided a bore (10) which extends along a longitudinal axis (12) of the bore (10) from an opening (11) of the bore (10) to a shoulder (14) facing the opening (11), and in the bore (10) is inserted an outer bearing bush (15) with a radially outer, cylindrical surface (16) abutting against the bore (10), a concave ball surface (17) facing radially inwards towards the longitudinal axis, a first end (18) which is arranged to abut against the shoulder (14), and a second end (19) of the bearing bush (15), which is axially opposite relative to the first end (18), and which is located near the opening (11) when the first end (18) abuts against the shoulder (14), and where the second ball joint part (2) has a pin (30) with a ball portion (31) with a radially outer surface (32) which is complementary relative to the ball surface (17) of the outer bearing bush (15), the ball portion (31) being slidably mounted in the outer bearing bush (15), characterised in that the device comprises a retaining ring (36) which is arranged to be attached to the housing (3) round the opening (11) and to secure the outer bearing bush (15) in the correct axial position relative to the housing (3).

2. A device according to claim 1, characterised in that a tubular bellows (40) is pulled on to the second ball joint part (2), and a first, circumferential edge area (41) of a first end portion (42) of the bellows (40) is arranged to extend sealingly between the second end (19) of the outer bearing bush (15) and the retaining ring (36) and that a second edge area (43) of the second end portion (44) of the bellows (40) is arranged to extend sealingly round the pin (30).

3. A device according to claim 1 or 2, characterised in that in the housing (3) radially outside the bore (10) and parallel to its longitudinal axis (12) there extend a plurality of through- going holes (33), where in an area between the opening (11) of the bore (10) and the shoulder (14) at least one of these holes (33) communicates with the bore (10), and a radially outer portion of the outer bearing bush (15) is arranged to protrude into these holes (33) when the outer bearing bush (15) abuts against the shoulder (14).

4. A device according to claim 3, characterised in that the second edge area (43) of the bellows (40) is arranged to be pressed against the pin (30) by means of a clamping ring (45).

5. A device according to claim 3 or 4, characterised in that in each hole (33) a screw (34) is inserted which is screwed into corresponding, threaded holes (35) in the retaining ring

(36).

6. A device according to claim 1 or 2, characterised in that a mounting ring (50) is arranged to secure the retaining ring (36) to the housing (3), the mounting ring (50) preferably extending in a direction substantially parallel to the retaining ring's (36) circumferential direction.

7. A device according to claim 6, characterised in that a first portion (51) of the mounting ring (50) is fixed to the housing (3) and a second portion (52) of the mounting ring (50) is connected to the retaining ring (36).

8. A device according to claim 7, characterised in that the second portion (52) of the mounting ring (50) is arranged to secure the first edge area (41) of the bellows sealingly to the retaining ring (36).

9. A device according to one of the claims 6-8, characterised in that the retaining ring (36) is provided with a groove (53) suitable for receiving the first edge area (41) of the bellows, the groove (53) preferably extending in the circumferential direction in the retaining ring's outer portion (54).

10. A device according to one of the claims 6-9, characterised in that the retaining ring's (50) inner portion (56) is provided with an inclined surface (57) extending in the retaining ring's (36) circumferential direction, the inclined surface (54) being designed so that there is a clearance between the inclined surface (57) and the ball portion's surface (32).

11. A device according to claim 10, characterised in that in some portions of the retaining ring's (36) circumferential direction the inclined surface (57) is arranged with an extra area positioned in an extension of the inclining surface (57) downwards.

12. A device according to claim 11, characterised in that the clearance between the extra area and the ball portion's surface (32) corresponds to the clearance between the inclined surface (57) and the ball portion's surface (32).

13. A device according to one of the claims 7-12, characterised in that holes are provided in the housing, preferably extending from the outside of the housing down to the shoulder (14).

14. A device according to one of the preceding claims, characterised in that there is a different angular deflection in two perpendicular directions in the ball joint, preferably directions coinciding with the vehicle's transverse direction and longitudinal direction.

15. A device according to one of the preceding claims, characterised in that the bore (10) is a blind bore.

16. A device according to one of the preceding claims, characterised in that the first ball joint part (1) is composed of a portion of a V-shaped rod (4) whose two free ends are arranged to be attached to a chassis of a vehicle, and the second ball joint part (2) is arranged to be attached to a wheel axle housing (6) of the vehicle.