Patent ID: 12234865

The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the disclosed embodiments. The description and drawings serve to enable one skilled in the art to make and use the disclosed embodiments, and are not intended to limit the scope of the disclosed embodiments in any manner. In respect of methods disclosed, the steps presented are exemplary in nature, and thus, the order of the steps is not necessary or critical.

The present technology relates to joint assemblies, such as constant velocity joints, used in motor vehicles. However, the present disclosure can apply to other types of joint assemblies used in motor vehicles or in other applications. Joint assemblies according to the disclosure are configured to facilitate a transmission of rotational forces and torque to components of a motor vehicle such as the wheels, for example.

FIGS.1-11show a joint assembly5according to an embodiment of the present disclosure. The joint assembly includes an inner joint member20and an outer joint member10. The joint assembly is configured as a tripode-type constant velocity joint. However, in other embodiments, the joint assembly can be configured as a ball-type constant velocity joint. It is understood that the joint assembly can be configured as a constant velocity joint or joint assembly of any type having an inner joint member and an outer joint member, as desired.FIG.12shows an enlarged view of an exemplary ball-type joint assembly.

As illustrated, the inner joint member20of the joint assembly5is configured as a tripode joint including three arms23extending radially outwardly from the inner joint member20. The inner joint member20is configured to be splined with a drive shaft21of the vehicle. For example, a central bore is splined and receives a splined drive shaft21. The inner joint member20includes a spider22with three arms extending radially therefrom, whereas one arm is identified with the reference numeral23. Each of the arms23includes a roller assembly engaging a distal end thereof, whereas one roller assembly is identified with the reference numeral24.

Each roller assembly24includes an outer roller25, an inner roller26, and rolling members27such as rollers of a needle bearing disposed between the outer roller and the inner roller (e.g.FIG.9). The roller assembly24can include retainers maintaining the rolling members27disposed between the inner roller26and the outer roller25. The roller assembly24is configured to permit an axial movement and angular displacement of the inner joint member20with respect to the outer joint member10as the inner joint member20is moved in and out of the outer joint member10.

The outer joint member10is configured as a hollow chamber having a closed end12, an open end on the opposite side, and an annular array of recesses or tracks11on an inner surface of a wall forming the chamber. The outer joint member10has a substantially tri-lobal cross-sectional shape. The tracks11include a pair of longitudinally extending opposing side walls13and14. Each of the tracks11receives one of the roller assemblies24of the inner joint member20, wherein the outer roller25of each of the roller assemblies24engages the side walls13,14of the outer joint member11.

A boot30is mounted to the open end of the outer joint member10. The boot30is made of an elastic material and comprises several foldings like a bellow. The boot30comprises a smaller opening32and a larger opening33. The drive shaft21runs through the smaller opening32and is tightly fixed to the drive shaft by means of a clamping ring41, for example. The larger opening33is put over the open end of the outer joint member10and is tightly fixed to the outer surface of the outer joint member10by means of a second clamping ring40. In addition, there is at least one circular groove16on the outer surface of the outer joint member10in the area of the open end (seeFIG.4). A circular tongue35on the inner surface of the boot30in the area of the larger opening33engages this groove16.

Furthermore, the boot30comprises three bulges34in the area of the larger opening33. These bulges34fit into corresponding recesses on the outer surface of the outer joint member10so that the boot30can tightly be fixed to the outer joint member10by means of a clamping ring40. These recesses are due to the tri-lobal form of the outer joint member10. Such outer joint member is also called tulip.

The boot30comprises several restrictors that extend into the three tracks11of the outer joint member10. Each track comprises two restrictors in form of leaves that project from the boot30into the tracks11. For example, the sections inFIGS.1to4show one restrictor31along a side wall14in a track11, whereas the section ofFIG.5shows two restrictors31and31′ along two opposing side walls13and14.FIGS.1,3and4show the inner joint member20with the roller assemblies24in a moving position.FIG.2shows the inner joint member20with the roller assemblies24almost in a blocked position when they start to have contact to the restrictors31,31′. In the situation ofFIG.5, the roller assembly24is blocked by the restrictors31,31′.

FIGS.6and7show these restrictors31,31′ on the boot30in more detail. They have the form of leaves that project from the boot30. Thereby, the foot of the restrictors has a greater thickness than the free end of the restrictors so that they are wedge-shaped. Their thickness decreases in axial direction towards the torque-transmitting elements. In addition, there are two stiffeners50and51between the two restrictors31,31′ that merge into the restrictors31,31′ with a radius. The restrictors31,31′ are supported against the bulges34by means of additional stiffeners52,53and52′,53′. All stiffeners are formed by protruding walls

FIG.9schematically shows a first embodiment of restrictors31and31′ that extend from a boot (not shown) into a track11with two opposing side walls13and14. The restrictors31,31′ narrow the width W of the track in the area of the open end of the outer joint member. A roller assembly has an inner roller26fixed to an arm23of the inner joint member. An outer joint member25is rotatably held on the inner roller26by means of roller members27.FIG.9shows this roller assembly in two positions. A first position is illustrated by dotted lines, whereas a second position is illustrated by continuous lines. The travel between these positions is indicated by double arrows. In the first position, the roller assembly can freely move along the track11. In the second position, the roller assembly has contacted the restrictors31,31′ so that its free travel towards the open end of the outer joint member is prevented.

The restrictors31,31′ extend along the side walls13,14whereby they have contact with the surfaces of the side walls. This contact can be a loose contact or the restrictors31,31′ are pressed into the track11. Preferably, the restrictors are made of an elastic material. If the inner joint member with the roller assembly moves further into the direction of the open end of the outer joint member (to the left), the outer roller25will deform and compress the restrictors31,31′. Then the roller assembly will be clamped between the two compressed restrictors31,31′. Thereby, an axial force F is used to generate forces F1and F2onto the restrictors31,31′ in the direction of the side walls. Form and size of the restrictors31,31′ are chosen adequately in order to achieve this deformation and compression. For example, the restrictors31,31′ should not be too thick at a contact point between restrictor and the outer roller of a roller assembly. In addition, an inclined surface36can help to form a wedge angle α. Angle α preferably is in the range between 0 and 35°, particularly between 0 and 20°, more particularly between 0 and 10°. The inclined surface36is a surface that contacts the roller assembly and provides for a ramp.

FIG.10shows another embodiment in a schematic illustration similar toFIG.9. The restrictors31,31′ used in this embodiment do not have contact with the side walls13and14. They are spaced apart from the side walls. Each restrictor31,31′ has a surface pointing in the direction of a side wall13,14along which it runs. The distance y between these surfaces is smaller than the width W of the track11. Even in this configuration, the restrictors31,31′ will not only stop the travel of the roller assembly in axial direction. When the outer roller of the roller assembly contacts the restrictors, the axial force F generates forces F1and F2onto the restrictors31,31′ in the direction of the side walls. The restrictors will bend and will be pressed between the outer roller25and each side wall. In this position, a wedge will be formed that clamps the roller assembly between the two restrictors.

Optionally, this clamping effect could even be used if the boot30is not tightly fastened to the outer hollow joint member yet. When the roller assembly contacts the restrictors, the boot might be pushed away from the outer joint member a little bit. However, as soon as the restrictors are deformed and clamped between the outer rollers and the side walls, the boot can no longer move.FIG.11shows an enlarged view of this situation. A leaf31projects from a boot30into a track along a side wall14. Thereby, the boot30maybe has had contact to an outer edge18of the open end of the outer joint member, but inFIG.11, the outer roller25has already pushed the boot30away from the edge18together with the restrictor31. However, at the same time the restrictor31has been deformed and pressed into the space between outer roller25and side wall14. Several stiffeners50,51,52and53on both sides of the restrictor31can help to keep the restrictor31in place. Another restrictor on the opposing side wall (not shown) has experienced the same. Therefore, the roller assembly is clamped between the two deformed restrictors. Now the boot30cannot be removed from the outer joint member10due to the friction forces between restrictor31, side wall14and outer roller25.

FIG.12shows an enlarged extracted view of another embodiment which is used to illustrate a restrictor according to an embodiment in a ball-type joint assembly6with an inner joint member20′ and an outer joint member10′. The torque-transmitting elements are balls. These balls24′ engage with tracks11′ in the outer joint member10′ and tracks11″ in the inner joint member20′ and are typically held in openings within a cage28. For ball-type joint assemblies, tracks with a semi-circular or gothic cross-section are often used. Each track also comprises two opposing side walls or sections of a wall running in axial direction. A ball engages these side walls or sections of a wall and is configured to move in an axial direction along the side walls or sections of a wall. For example, the enlarged extracted view ofFIG.11shows that the ball24′ engages the side wall14′ in the track11′ in the outer joint member10′. A boot30comprises at least one restrictor31″ that extends into the track11′ along a side wall14′. The boot30can comprise at least one restrictor31″, in particular two restrictors, for each track. Thereby, the form of the restrictor31″ is adapted to the shape of the track11′.