Title of Invention

JOINT UNIT OF A CONTROL ARM OF A WHEEL SUSPENSION IN A MOTOR VEHICLE.

Abstract The invention relates to a joint unit of a steering unit of a wheel suspension in a motor vehicle, with a housing (1) and a journal (2) which is slidingly mounted in the housing by means of a spheroid bearing surface (3), and the joint unit has a catchment device (4) to prevent the housing (1) from becoming completely separated from the journal (2) which spans a part of the housing (1) without contact during normal operation. As proposed by the invention, the catchment device (4) has at least one flexible catch strap or at least one fixing bracket (4.1, 4.2) with a recess (4.1.1, 4.2.1) through which a catch pin (1.1,1.2) of the housing extends without contact during normal operation or at least two fixing brackets (4.1 and 4.2).
Full Text FORM 2
THE PATENT ACT 1970 (39 of 1970)
The Patents Rules, 2003 COMPLETE SPECIFICATION
(See Section 10, and rule 13)
1. TITLE OF INVENTION JOINT UNIT

2. APPLICANT(S)
a) Name
b) Nationality
c) Address

ZF FRIEDRICHSHAFEN AG GERMAN Company 88038 FRIEDRICHSHAFEN GERMANY

3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

Description
The invention relates to a joint unit of the type outlined in the introductory part of claim 1.
Wheel suspensions in motor vehicles have different bearings respectively joints, depending on their respective disposition and function. For example, ball and socket joints are suitable as a means of permitting a relative movement between two components in several degrees of freedom. Also known are joint units which have coatings of elastomer in order to damp vibrations transmitted via the wheel. Consequently, by means of known joint units, the properties of the vehicle and, in this instance, those of the wheel suspension in particular can be influenced not only in terms of wheel guidance but also from the point of view of increasing comfort.
The joint units used in chassis components are safety components which are subjected to a high amount of stress and are usually based on a design of the "safe life principle", in other words to remain operationally safe for the entire service life of a motor vehicle to a multiple degree of reliability. In spite of this, purely theoretical events or very unfavourable causal connections are conceivable, which could lead to total failure of such joint units. This might be possible due to changing wear of the bearing shell or the formation of corrosion on the ball journal because dirt or water has been able to penetrate the joint interior following failure of the sealing system, for example. The consequence could be that a joint unit damaged in this manner could become completely separated, in other words the connection between the housing and journal would come apart.
Known joint units comprise a housing and a journal, and the journal mounted in the housing by means of a spheroid bearing surface is able to effect a sliding movement inside the housing. The spheroid bearing surface, which may be an integral part of the journal or may be connected to it in the sense of a fitting, is a standard shape for bearing geometry in the prior art. Patent specification DE-OS 23 50 087 or EP 1 036
2

280 Al, for example, disclose a joint unit of this type. Since components of known joint units are joined to one another so as to permit relative movements, making allowance for any wear which occurs between these components permitting relative movement is a major quality feature. Consequently, considerable efforts have been made to keep wear as low as possible throughout the entire service life of the joint unit or to eliminate it altogether. For this reason, known joint units have expensive sealing systems in order to prevent water or dirt from getting into the inner joint components. The existing solutions have been tried and tested and usually guarantee functional reliability of the joint unit far beyond the service life of the motor vehicle, thereby ruling out failure of the joint unit.
However if repair or maintenance work is needed on the wheel suspension of a vehicle, for example, a situation might arise in which parts of the joint unit are damaged inadvertently and unnoticed. If such a situation were actually to occur, penetration of the interior of the joint unit by water and/ or dirt, as mentioned above, could no longer be reliably ruled out. However, this would lead to premature, more pronounced wear of the components of the joint unit. In the extreme situation, the housing could conceivably become totally separated (severed) from the journal. However, such a situation must be ruled out for safety reasons. To date, no solutions are known from the prior art that would prevent complete separation between the housing and journal and so that a vehicle exhibiting this sort of wear could still be brought to the nearest mechanic with an emergency function.
The underlying objective of the invention is to improve a joint unit so that even if the housing becomes completely separated from the journal, an emergency function of the joint unit is still assured.
This objective is achieved on the basis of the characterising features of claim 1. Other embodiments of the invention are defined in the adjoining dependent claims.
As proposed by the invention, in order to prevent complete severance (separation) of
3

the housing from the journal, the joint unit is equipped with a catchment device. The catchment device may comprise at least one flexible catch strap or at least one fixing bracket with a recess, into which a catch pin of the housing projects without contact during normal operation, or at least two fixing brackets.
If a flexible catch strap is used to implement the principle of the invention, it may also span the housing by means of a direct abutment contact. As a result of the guaranteed flexibility of the catch strap, there is no impairment to the characteristics of the joint unit to speak of. However, it may be preferable to use a catch strap which spans at least certain portions of the housing without contact and does not assume its actual function unless the joint components try to come apart from one another. With a catch strap of this type, the catchment device can be made to a very simple design and can therefore also be made available inexpensively as a unit which can be retrofitted on a joint unit proposed by the invention.
In another embodiment of the invention, the housing is equipped with at least one catch pin, which, during normal operation, projects without contact into a recess provided on the co-operating fixing bracket specifically for this purpose. The contactless component pairing between the catch pin and fixing bracket is necessary because during normal operation, the joint unit must be able to fulfil its function without impairment to the wheel suspension of the motor vehicle.
A very simple mechanical embodiment of a catchment device may be one whereby the catchment device comprises at least two fixing brackets. These fixing brackets span at least certain portions of the housing of the joint unit so that, in the event of the housing becoming separated from the journal due to wear, the catchment device is in a position to fix components that are coming apart from one another in an emergency position.
In order to ensure that the function of a joint unit proposed by the invention disposed in the vehicle remains assured without restriction, the catchment device
4

should span at least a part of the housing without contact during normal operation. Accordingly, there is preferably no or only a slight contact between the catchment device proposed by the invention and the housing of the joint unit, so that the ability of the components of the wheel suspension to move relative to one another in their freedom of movement is not impaired. By "normal operation" is meant failure-free functioning of the joint unit in keeping with its intended purpose.
Overall, a redundant safety system can therefore be provided for a joint unit of a steering unit of a wheel suspension in a motor vehicle. The system is redundant because under the normal circumstances and conditions under which a motor vehicle is used, a joint unit of this type is designed to such a high standard of safety that total failure is ruled out. As proposed by the invention, a very simple, preferably mechanical safety system is provided, which can also be used with known joint units because it does not affect them in terms of their function. Consequently, it is also possible to fit known joint units with the catchment device, thereby further increasing the safety of motor vehicles.
In another embodiment of the invention, the fixing bracket spans the housing in a claw-type arrangement and during normal operation without contact. This variant offers considerable advantages in terms of weight.
It has also proved to be of advantage if the catchment device is secured directly to a mounting flange of the joint unit or integrally formed on this mounting flange, in other words is of an integral design with it. This means that a known joint unit can be subsequently fitted with a catchment device proposed by the invention without much extra effort. This is possible in particular if the catchment device is fitted to the mounting flange. Otherwise, the mounting flange as a whole would have to be changed.
It is also of particular advantage if the catch strap is an integral part of a sealing bellows disposed between the housing and journal to protect the inner joint
5

components from dirt. This being the case, the catch strap can easily be made as an integral part of the sealing bellows or can be subsequently connected to it. In order to guarantee the function of the catchment device, in one embodiment of the catch strap as an integral part or addition to the sealing bellows, particular attention must be paid to the fixing of the sealing bellows peripheral regions on the housing respectively on the journal, because fulfilment of the inventive function is essentially dependent on these fixing surfaces.
In a manner known per se, the journal of a joint unit proposed by the invention can be affixed to the mounting flange or made integrally with it, and the spheroid bearing surface may also be an integral part of a joint ball mounted on the journal or integrally formed on it.
Another option is to use a joint ball which is accommodated in a bearing shell inserted in the housing to achieve the solution proposed by the invention. This being the case, one particular application of the joint unit proposed by the invention and described here is one whereby it constitutes the central joint of a wishbone of a motor vehicle wheel suspension, especially a utility vehicle, and the housing is therefore connected to the steering arms of the wishbone.
Preferred embodiments of a joint unit proposed by the invention will be described in more detail below with reference to the drawings.
Of these:
Figure 1: is a schematically simplified partial section through a first embodiment
of a joint unit proposed by the invention, taking the example of a
wishbone central joint of a utility vehicle,
Figure 2: is a perspective diagram of the wishbone central joint illustrated in Figure 1,
6

Figure 3: shows a second embodiment of a joint unit proposed by the invention based on the example of a central joint for a wishbone of a utility vehicle,
Figure 4: shows a third embodiment of a joint unit proposed by the invention, likewise illustrated as the wishbone central joint of a utility vehicle, and
Figure 5: shows a fourth embodiment of a joint unit proposed by the invention with a catchment device, again based on the example of a wishbone central joint for a utility vehicle.
The essential features proposed by the invention can be explained with reference to the embodiment of the joint unit proposed by the invention illustrated in Figure 1 as an example, which is shown in partial section and schematically simplified, although this does not mean that the subject matter is restricted to that specifically illustrated in this or any other of the drawings. The reference numbers used below are the same as those used in the individual drawings for identical components or component units.
The joint unit illustrated in Figure 1 has a housing 1. The housing 1 is equipped with a pin-shaped connecting region, on which only one steering arm 8 of a steering arm pair 7,8 of a wishbone for a utility vehicle is visible. The housing 1 in this instance is of a design open at one side. It has an inner cavity in which a bearing shell 6 is inserted. The bearing shell affords a bearing, function which damps vibrations and simultaneously imparts sliding properties inside the joint unit. The bearing shell 6 in turn supports the spheroid bearing surface 3 of a joint ball 3.1 as viewed looking into the joint. The joint ball 3.1 is secured by fitting it onto a journal 2 by means of a screw connection 10. A locking ring 11 is used as a means of securing the bearing shell 6 to prevent any axial migration out of the opening of the housing 1.
7

On the external face, the housing 1 has a catch pin 1,1/ which projects out from the housing surface. The projecting part of the catch pin 1.1 extends through a recess 4.1.1. of a fixing bracket 4.1 without contact, and the fixing bracket 4.1 in the embodiment of the joint unit proposed by the invention illustrated as an example here constitutes the catchment device 4. The fixing bracket 4.1 is secured to the mounting flange 5 by means of a screw connection during fitting of the joint unit on the axle of a utility vehicle.
A sealing bellows 9 is used to seal the inner joint components of the joint unit illustrated in Figure 1 from dirt. It has two fixing regions 9.1 and 9.2 by means of which it is secured in a sealing arrangement to the housing 1 and to the journal 2.
During normal operation of the illustrated joint unit, there is no abutting contact between the catch pin 1.1 and the fixing bracket 4.1. To this end, the slot-like recess 4.1.1 (more readily visible in Figure 2) in the fixing bracket 4.1 is of sufficiently large dimensions. In the situation where the housing 1 starts to separate from the journal 2, this would lead to an axial movement of the housing 1 in the direction of the bearing mid-axis, so that the catch pin 1.1 would migrate in the direction of the top bow-shaped region of the fixing bracket 4.1. This ability of the housing to move in the axial direction relative to the journal 2 would therefore be possible until the catch pin 1.1 fulfils its function and moves into abutment on the fixing bracket 4.1. The vehicle driver would unavoidably notice this type of problem on the wheel suspension so that the vehicle could therefore be taken to a mechanic with the emergency function assured to enable the necessary components to be replaced.
Figure 2 shows a perspective view of the joint unit illustrated in Figure 1. The steering arms 7 and 8, parts of which are illustrated, are integral parts of a wishbone for utility vehicles. The catch pin 1.1 integrally formed on the housing 1 may also be seen on the side lying opposite the steering arms 7 and 8. This catch pin 1.1 extends through the recess 4.1.1 of the catchment device 4, which in this instance is provided in the form of the fixing bracket 4.1. The fixing bracket 4.1 is secured to the mounting
8

flange 5 on the axle body of the rear axle of a utility vehicle in the manner described above.
Figure 2 also illustrates the external face of the sealing bellows 9 disposed between the housing 1 and journal 2 to protect the inner joint components against penetration by dirt. The sealing bellows 9 is retained in a sealing arrangement on the above-mentioned parts of the joint unit 1 by means of its fixing regions 9.1 and 9.2.
By contrast with the embodiments described above, Figure 3 illustrates a variant of a joint unit 1 with two catchment devices lying opposite one another on the mounting flange 5, which in this instance each comprise a fixing bracket 4.1 respectively 4.2. The fixing bracket 4.1 has a slot-like recess 4.1.1, whilst a recess 4.2.1 of this type is provided in fixing bracket 4.2. A catch pin 1.1 and 1.2 extends respectively through each of these recesses 4.1.1 and 4.2.1. This being the case, the catch pin 1.1 respectively 1.2 secured to the housing 1 is able to move freely inside said recesses without any abutment contact occurring between the catch pin and fixing bracket 4.1 respectively 4.2, provided normal operation is assured, in other words the illustrated joint unit is functioning safely. As with the embodiment described above, the central joint illustrated in Figure 3 has a sealing bellows 9 with its fixing regions 9.1 and 9.2. The fixing brackets 4.1 respectively 4.2 are also secured to the mounting flange 5 in this variant.
Another embodiment of a joint unit 1 proposed by the invention is illustrated in Figure 4. By contrast with the variants of a joint unit described above, the fixing brackets 4.1 and 4.2 in this instance are bow-shaped and span the co-operating catch pin 1.1 respectively 1.2 as part of the housing 1 in an extended plane. More or less at the centre, the fixing brackets 4.1 and 4.2 have a geometry which enables the catch pin 1.1 respectively 1.2 to move into contact with the fixing bracket 4.1 respectively 4.2 at a defined position if the housing 1 separates from the journal 2, thereby assuring the emergency function of the joint unit proposed by the invention. The fixing brackets 4.1 and 4.2 are secured - as explained above - by fixing the mounting
9

flange 5 on the vehicle axle of the utility vehicle.
The joint unit illustrated in a perspective view in Figure 5 also assures an emergency function in a simple manner in the situation where the housing 1 comes apart from the journal 2. In this instance, no catch pin is provided on the housing. Instead, the catchment device 4 comprises two respective oppositely lying fixing brackets 4.1 and 4.2 spanning a part of the surface of the housing 1 without contact as long as the joint unit is fulfilling its function. The end portions of the fixing brackets 4.1 and 4.2 are at a distance from the surface of the housing 1 as viewed in the axial direction of the bearing mid-axis. If the housing 1 starts to come apart from the journal 2, an abutting contact is made between the surface of the housing 1 and the claw-shaped end regions of the of the fixing brackets 4.1 and 4.2. In order to prevent these claw-shaped end regions from slipping, a co-operating bead-shaped raised area 12,13 is provided on the surface of the housing 1 in the embodiment illustrated here. This bead-shaped raised area 12 respectively 13 need not necessarily be provided but is deemed meaningful in the embodiment illustrated.
10

List of reference numbers


11

WE CLAIM:
1. Joint unit of a steering unit of a wheel suspension in a motor vehicle, with a
housing (1) and a journal (2), which is slidingly mounted in the housing by
means of a spheroid bearing surface (3), which joint unit has a catchment
device (4) to prevent the housing (1) from becoming totally separated from
the journal (2) which spans a part of the housing (1) without contact during
normal operation,
characterised in that
the catchment device (4) comprises at least one flexible catchment strap or at least one fixing bracket (4.1, 4.2) with a recess (4.1.1, 4.2.1) through which a catch pin (1.1, 1.2) of the housing extends without contact during normal operation or at least two fixing brackets (4.1 and 4.2).
2. Joint unit as claimed in claim 1,
characterised in that
the fixing brackets (4.1 and 4.2) span the housing (1) in a claw-shaped arrangement and without contact during normal operation.
3. Joint unit as claimed in claim 1 or 2,
characterised in that
the catchment device (4) is secured to a mounting flange (5) of the joint unit or is integrally formed on the mounting flange (5).
4. Joint unit as claimed in claim 1,
characterised in that
the catch strap is an integral part of a sealing bellows (9) disposed between the housing (1) and journal (2) to protect the inner joint components from dirt.
5. Joint unit as claimed in one of the preceding claims,
characterised in that
the journal (2) is secured to the mounting flange (5) or is integrally formed on
12

it and the spheroid bearing surface (3) is an integral part of a joint ball (3.1) mounted on the journal (2) or integrally formed on it.
Joint unit as claimed in claim 5,
characterised in that
the joint ball (3.1) is accommodated in a bearing shell (6) inserted in the
housing (1).
Joint unit as claimed in one of the preceding claims,
characterised in that
the joint unit constitutes the central joint of a wishbone steering unit of a
motor vehicle wheel suspension, in particular a utility vehicle, and the
housing (1) is connected to steering arms (7,8).
Dated this 3rd day of May, 2007
13

ABSTRACT
The invention relates to a joint unit of a steering unit of a wheel suspension in a motor vehicle, with a housing (1) and a journal (2) which is slidingly mounted in the housing by means of a spheroid bearing surface (3), and the joint unit has a catchment device (4) to prevent the housing (1) from becoming completely separated from the journal (2) which spans a part of the housing (1) without contact during normal operation.
As proposed by the invention, the catchment device (4) has at least one flexible catch strap or at least one fixing bracket (4.1, 4.2) with a recess (4.1.1, 4.2.1) through which a catch pin (1.1,1.2) of the housing extends without contact during normal operation or at least two fixing brackets (4.1 and 4.2).
To,
The Controller of Patents,
The Patent Office,
Mumbai
14
Figure 1

FORM 2
THE PATENT ACT 1970 (39 of 1970)
The Patents Rules, 2003 COMPLETE SPECIFICATION
(See Section 10, and rule 13)
1. TITLE OF INVENTION JOINT UNIT

2. APPLICANT(S)
a) Name
b) Nationality
c) Address

ZF FRIEDRICHSHAFEN AG GERMAN Company 88038 FRIEDRICHSHAFEN GERMANY

3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

Description
The invention relates to a joint unit of the type outlined in the introductory part of claim 1.
Wheel suspensions in motor vehicles have different bearings respectively joints, depending on their respective disposition and function. For example, ball and socket joints are suitable as a means of permitting a relative movement between two components in several degrees of freedom. Also known are joint units which have coatings of elastomer in order to damp vibrations transmitted via the wheel. Consequently, by means of known joint units, the properties of the vehicle and, in this instance, those of the wheel suspension in particular can be influenced not only in terms of wheel guidance but also from the point of view of increasing comfort.
The joint units used in chassis components are safety components which are subjected to a high amount of stress and are usually based on a design of the "safe life principle", in other words to remain operationally safe for the entire service life of a motor vehicle to a multiple degree of reliability. In spite of this, purely theoretical events or very unfavourable causal connections are conceivable, which could lead to total failure of such joint units. This might be possible due to changing wear of the bearing shell or the formation of corrosion on the ball journal because dirt or water has been able to penetrate the joint interior following failure of the sealing system, for example. The consequence could be that a joint unit damaged in this manner could become completely separated, in other words the connection between the housing and journal would come apart.
Known joint units comprise a housing and a journal, and the journal mounted in the housing by means of a spheroid bearing surface is able to effect a sliding movement inside the housing. The spheroid bearing surface, which may be an integral part of the journal or may be connected to it in the sense of a fitting, is a standard shape for bearing geometry in the prior art. Patent specification DE-OS 23 50 087 or EP 1 036
2

280 Al, for example, disclose a joint unit of this type. Since components of known joint units are joined to one another so as to permit relative movements, making allowance for any wear which occurs between these components permitting relative movement is a major quality feature. Consequently, considerable efforts have been made to keep wear as low as possible throughout the entire service life of the joint unit or to eliminate it altogether. For this reason, known joint units have expensive sealing systems in order to prevent water or dirt from getting into the inner joint components. The existing solutions have been tried and tested and usually guarantee functional reliability of the joint unit far beyond the service life of the motor vehicle, thereby ruling out failure of the joint unit.
However if repair or maintenance work is needed on the wheel suspension of a vehicle, for example, a situation might arise in which parts of the joint unit are damaged inadvertently and unnoticed. If such a situation were actually to occur, penetration of the interior of the joint unit by water and/ or dirt, as mentioned above, could no longer be reliably ruled out. However, this would lead to premature, more pronounced wear of the components of the joint unit. In the extreme situation, the housing could conceivably become totally separated (severed) from the journal. However, such a situation must be ruled out for safety reasons. To date, no solutions are known from the prior art that would prevent complete separation between the housing and journal and so that a vehicle exhibiting this sort of wear could still be brought to the nearest mechanic with an emergency function.
The underlying objective of the invention is to improve a joint unit so that even if the housing becomes completely separated from the journal, an emergency function of the joint unit is still assured.
This objective is achieved on the basis of the characterising features of claim 1. Other embodiments of the invention are defined in the adjoining dependent claims.
As proposed by the invention, in order to prevent complete severance (separation) of
3

the housing from the journal, the joint unit is equipped with a catchment device. The catchment device may comprise at least one flexible catch strap or at least one fixing bracket with a recess, into which a catch pin of the housing projects without contact during normal operation, or at least two fixing brackets.
If a flexible catch strap is used to implement the principle of the invention, it may also span the housing by means of a direct abutment contact. As a result of the guaranteed flexibility of the catch strap, there is no impairment to the characteristics of the joint unit to speak of. However, it may be preferable to use a catch strap which spans at least certain portions of the housing without contact and does not assume its actual function unless the joint components try to come apart from one another. With a catch strap of this type, the catchment device can be made to a very simple design and can therefore also be made available inexpensively as a unit which can be retrofitted on a joint unit proposed by the invention.
In another embodiment of the invention, the housing is equipped with at least one catch pin, which, during normal operation, projects without contact into a recess provided on the co-operating fixing bracket specifically for this purpose. The contactless component pairing between the catch pin and fixing bracket is necessary because during normal operation, the joint unit must be able to fulfil its function without impairment to the wheel suspension of the motor vehicle.
A very simple mechanical embodiment of a catchment device may be one whereby the catchment device comprises at least two fixing brackets. These fixing brackets span at least certain portions of the housing of the joint unit so that, in the event of the housing becoming separated from the journal due to wear, the catchment device is in a position to fix components that are coming apart from one another in an emergency position.
In order to ensure that the function of a joint unit proposed by the invention disposed in the vehicle remains assured without restriction, the catchment device
4

should span at least a part of the housing without contact during normal operation. Accordingly, there is preferably no or only a slight contact between the catchment device proposed by the invention and the housing of the joint unit, so that the ability of the components of the wheel suspension to move relative to one another in their freedom of movement is not impaired. By "normal operation" is meant failure-free functioning of the joint unit in keeping with its intended purpose.
Overall, a redundant safety system can therefore be provided for a joint unit of a steering unit of a wheel suspension in a motor vehicle. The system is redundant because under the normal circumstances and conditions under which a motor vehicle is used, a joint unit of this type is designed to such a high standard of safety that total failure is ruled out. As proposed by the invention, a very simple, preferably mechanical safety system is provided, which can also be used with known joint units because it does not affect them in terms of their function. Consequently, it is also possible to fit known joint units with the catchment device, thereby further increasing the safety of motor vehicles.
In another embodiment of the invention, the fixing bracket spans the housing in a claw-type arrangement and during normal operation without contact. This variant offers considerable advantages in terms of weight.
It has also proved to be of advantage if the catchment device is secured directly to a mounting flange of the joint unit or integrally formed on this mounting flange, in other words is of an integral design with it. This means that a known joint unit can be subsequently fitted with a catchment device proposed by the invention without much extra effort. This is possible in particular if the catchment device is fitted to the mounting flange. Otherwise, the mounting flange as a whole would have to be changed.
It is also of particular advantage if the catch strap is an integral part of a sealing bellows disposed between the housing and journal to protect the inner joint
5

components from dirt. This being the case, the catch strap can easily be made as an integral part of the sealing bellows or can be subsequently connected to it. In order to guarantee the function of the catchment device, in one embodiment of the catch strap as an integral part or addition to the sealing bellows, particular attention must be paid to the fixing of the sealing bellows peripheral regions on the housing respectively on the journal, because fulfilment of the inventive function is essentially dependent on these fixing surfaces.
In a manner known per se, the journal of a joint unit proposed by the invention can be affixed to the mounting flange or made integrally with it, and the spheroid bearing surface may also be an integral part of a joint ball mounted on the journal or integrally formed on it.
Another option is to use a joint ball which is accommodated in a bearing shell inserted in the housing to achieve the solution proposed by the invention. This being the case, one particular application of the joint unit proposed by the invention and described here is one whereby it constitutes the central joint of a wishbone of a motor vehicle wheel suspension, especially a utility vehicle, and the housing is therefore connected to the steering arms of the wishbone.
Preferred embodiments of a joint unit proposed by the invention will be described in more detail below with reference to the drawings.
Of these:
Figure 1: is a schematically simplified partial section through a first embodiment
of a joint unit proposed by the invention, taking the example of a
wishbone central joint of a utility vehicle,
Figure 2: is a perspective diagram of the wishbone central joint illustrated in Figure 1,
6

Figure 3: shows a second embodiment of a joint unit proposed by the invention based on the example of a central joint for a wishbone of a utility vehicle,
Figure 4: shows a third embodiment of a joint unit proposed by the invention, likewise illustrated as the wishbone central joint of a utility vehicle, and
Figure 5: shows a fourth embodiment of a joint unit proposed by the invention with a catchment device, again based on the example of a wishbone central joint for a utility vehicle.
The essential features proposed by the invention can be explained with reference to the embodiment of the joint unit proposed by the invention illustrated in Figure 1 as an example, which is shown in partial section and schematically simplified, although this does not mean that the subject matter is restricted to that specifically illustrated in this or any other of the drawings. The reference numbers used below are the same as those used in the individual drawings for identical components or component units.
The joint unit illustrated in Figure 1 has a housing 1. The housing 1 is equipped with a pin-shaped connecting region, on which only one steering arm 8 of a steering arm pair 7,8 of a wishbone for a utility vehicle is visible. The housing 1 in this instance is of a design open at one side. It has an inner cavity in which a bearing shell 6 is inserted. The bearing shell affords a bearing, function which damps vibrations and simultaneously imparts sliding properties inside the joint unit. The bearing shell 6 in turn supports the spheroid bearing surface 3 of a joint ball 3.1 as viewed looking into the joint. The joint ball 3.1 is secured by fitting it onto a journal 2 by means of a screw connection 10. A locking ring 11 is used as a means of securing the bearing shell 6 to prevent any axial migration out of the opening of the housing 1.
7

On the external face, the housing 1 has a catch pin 1,1/ which projects out from the housing surface. The projecting part of the catch pin 1.1 extends through a recess 4.1.1. of a fixing bracket 4.1 without contact, and the fixing bracket 4.1 in the embodiment of the joint unit proposed by the invention illustrated as an example here constitutes the catchment device 4. The fixing bracket 4.1 is secured to the mounting flange 5 by means of a screw connection during fitting of the joint unit on the axle of a utility vehicle.
A sealing bellows 9 is used to seal the inner joint components of the joint unit illustrated in Figure 1 from dirt. It has two fixing regions 9.1 and 9.2 by means of which it is secured in a sealing arrangement to the housing 1 and to the journal 2.
During normal operation of the illustrated joint unit, there is no abutting contact between the catch pin 1.1 and the fixing bracket 4.1. To this end, the slot-like recess 4.1.1 (more readily visible in Figure 2) in the fixing bracket 4.1 is of sufficiently large dimensions. In the situation where the housing 1 starts to separate from the journal 2, this would lead to an axial movement of the housing 1 in the direction of the bearing mid-axis, so that the catch pin 1.1 would migrate in the direction of the top bow-shaped region of the fixing bracket 4.1. This ability of the housing to move in the axial direction relative to the journal 2 would therefore be possible until the catch pin 1.1 fulfils its function and moves into abutment on the fixing bracket 4.1. The vehicle driver would unavoidably notice this type of problem on the wheel suspension so that the vehicle could therefore be taken to a mechanic with the emergency function assured to enable the necessary components to be replaced.
Figure 2 shows a perspective view of the joint unit illustrated in Figure 1. The steering arms 7 and 8, parts of which are illustrated, are integral parts of a wishbone for utility vehicles. The catch pin 1.1 integrally formed on the housing 1 may also be seen on the side lying opposite the steering arms 7 and 8. This catch pin 1.1 extends through the recess 4.1.1 of the catchment device 4, which in this instance is provided in the form of the fixing bracket 4.1. The fixing bracket 4.1 is secured to the mounting
8

flange 5 on the axle body of the rear axle of a utility vehicle in the manner described above.
Figure 2 also illustrates the external face of the sealing bellows 9 disposed between the housing 1 and journal 2 to protect the inner joint components against penetration by dirt. The sealing bellows 9 is retained in a sealing arrangement on the above-mentioned parts of the joint unit 1 by means of its fixing regions 9.1 and 9.2.
By contrast with the embodiments described above, Figure 3 illustrates a variant of a joint unit 1 with two catchment devices lying opposite one another on the mounting flange 5, which in this instance each comprise a fixing bracket 4.1 respectively 4.2. The fixing bracket 4.1 has a slot-like recess 4.1.1, whilst a recess 4.2.1 of this type is provided in fixing bracket 4.2. A catch pin 1.1 and 1.2 extends respectively through each of these recesses 4.1.1 and 4.2.1. This being the case, the catch pin 1.1 respectively 1.2 secured to the housing 1 is able to move freely inside said recesses without any abutment contact occurring between the catch pin and fixing bracket 4.1 respectively 4.2, provided normal operation is assured, in other words the illustrated joint unit is functioning safely. As with the embodiment described above, the central joint illustrated in Figure 3 has a sealing bellows 9 with its fixing regions 9.1 and 9.2. The fixing brackets 4.1 respectively 4.2 are also secured to the mounting flange 5 in this variant.
Another embodiment of a joint unit 1 proposed by the invention is illustrated in Figure 4. By contrast with the variants of a joint unit described above, the fixing brackets 4.1 and 4.2 in this instance are bow-shaped and span the co-operating catch pin 1.1 respectively 1.2 as part of the housing 1 in an extended plane. More or less at the centre, the fixing brackets 4.1 and 4.2 have a geometry which enables the catch pin 1.1 respectively 1.2 to move into contact with the fixing bracket 4.1 respectively 4.2 at a defined position if the housing 1 separates from the journal 2, thereby assuring the emergency function of the joint unit proposed by the invention. The fixing brackets 4.1 and 4.2 are secured - as explained above - by fixing the mounting
9

flange 5 on the vehicle axle of the utility vehicle.
The joint unit illustrated in a perspective view in Figure 5 also assures an emergency function in a simple manner in the situation where the housing 1 comes apart from the journal 2. In this instance, no catch pin is provided on the housing. Instead, the catchment device 4 comprises two respective oppositely lying fixing brackets 4.1 and 4.2 spanning a part of the surface of the housing 1 without contact as long as the joint unit is fulfilling its function. The end portions of the fixing brackets 4.1 and 4.2 are at a distance from the surface of the housing 1 as viewed in the axial direction of the bearing mid-axis. If the housing 1 starts to come apart from the journal 2, an abutting contact is made between the surface of the housing 1 and the claw-shaped end regions of the of the fixing brackets 4.1 and 4.2. In order to prevent these claw-shaped end regions from slipping, a co-operating bead-shaped raised area 12,13 is provided on the surface of the housing 1 in the embodiment illustrated here. This bead-shaped raised area 12 respectively 13 need not necessarily be provided but is deemed meaningful in the embodiment illustrated.
10

List of reference numbers


11

WE CLAIM:
1. Joint unit of a steering unit of a wheel suspension in a motor vehicle, with a
housing (1) and a journal (2), which is slidingly mounted in the housing by
means of a spheroid bearing surface (3), which joint unit has a catchment
device (4) to prevent the housing (1) from becoming totally separated from
the journal (2) which spans a part of the housing (1) without contact during
normal operation,
characterised in that
the catchment device (4) comprises at least one flexible catchment strap or at least one fixing bracket (4.1, 4.2) with a recess (4.1.1, 4.2.1) through which a catch pin (1.1, 1.2) of the housing extends without contact during normal operation or at least two fixing brackets (4.1 and 4.2).
2. Joint unit as claimed in claim 1,
characterised in that
the fixing brackets (4.1 and 4.2) span the housing (1) in a claw-shaped arrangement and without contact during normal operation.
3. Joint unit as claimed in claim 1 or 2,
characterised in that
the catchment device (4) is secured to a mounting flange (5) of the joint unit or is integrally formed on the mounting flange (5).
4. Joint unit as claimed in claim 1,
characterised in that
the catch strap is an integral part of a sealing bellows (9) disposed between the housing (1) and journal (2) to protect the inner joint components from dirt.
5. Joint unit as claimed in one of the preceding claims,
characterised in that
the journal (2) is secured to the mounting flange (5) or is integrally formed on
12

it and the spheroid bearing surface (3) is an integral part of a joint ball (3.1) mounted on the journal (2) or integrally formed on it.
Joint unit as claimed in claim 5,
characterised in that
the joint ball (3.1) is accommodated in a bearing shell (6) inserted in the
housing (1).
Joint unit as claimed in one of the preceding claims,
characterised in that
the joint unit constitutes the central joint of a wishbone steering unit of a
motor vehicle wheel suspension, in particular a utility vehicle, and the
housing (1) is connected to steering arms (7,8).
Dated this 3rd day of May, 2007
13

ABSTRACT
The invention relates to a joint unit of a steering unit of a wheel suspension in a motor vehicle, with a housing (1) and a journal (2) which is slidingly mounted in the housing by means of a spheroid bearing surface (3), and the joint unit has a catchment device (4) to prevent the housing (1) from becoming completely separated from the journal (2) which spans a part of the housing (1) without contact during normal operation.
As proposed by the invention, the catchment device (4) has at least one flexible catch strap or at least one fixing bracket (4.1, 4.2) with a recess (4.1.1, 4.2.1) through which a catch pin (1.1,1.2) of the housing extends without contact during normal operation or at least two fixing brackets (4.1 and 4.2).
To,
The Controller of Patents,
The Patent Office,
Mumbai
14
Figure 1


Documents:

647-mumnp-2007-abstract(8-2-2010).pdf

647-MUMNP-2007-ABSTRACT(GRANTED)-(1-11-2010).pdf

647-mumnp-2007-abstract.doc

647-mumnp-2007-abstract.pdf

647-MUMNP-2007-CANCELLED PAGES(15-9-2010).pdf

647-MUMNP-2007-CANCELLED PAGES(8-2-2010).pdf

647-mumnp-2007-claims(8-2-2010).pdf

647-MUMNP-2007-CLAIMS(AMENDED)-(15-9-2010).pdf

647-MUMNP-2007-CLAIMS(AMENDED)-(8-2-2010).pdf

647-MUMNP-2007-CLAIMS(GRANTED)-(1-11-2010).pdf

647-mumnp-2007-claims.doc

647-mumnp-2007-claims.pdf

647-MUMNP-2007-CORRESPONDENCE(15-9-2010).pdf

647-MUMNP-2007-CORRESPONDENCE(17-9-2010).pdf

647-mumnp-2007-correspondence(29-8-2007).pdf

647-mumnp-2007-correspondence(ipo)-(17-2-2009).pdf

647-MUMNP-2007-CORRESPONDENCE(IPO)-(2-11-2010).pdf

647-mumnp-2007-correspondence-others.pdf

647-mumnp-2007-correspondence-received.pdf

647-mumnp-2007-description (complete).pdf

647-mumnp-2007-description(complete)-(8-2-2010).pdf

647-MUMNP-2007-DESCRIPTION(GRANTED)-(1-11-2010).pdf

647-MUMNP-2007-DRAWING(3-5-2007).pdf

647-MUMNP-2007-DRAWING(8-2-2010).pdf

647-MUMNP-2007-DRAWING(GRANTED)-(1-11-2010).pdf

647-mumnp-2007-drawings.pdf

647-mumnp-2007-form 1(29-8-2007).pdf

647-MUMNP-2007-FORM 1(3-5-2007).pdf

647-MUMNP-2007-FORM 1(8-2-2010).pdf

647-mumnp-2007-form 2(8-2-2010).pdf

647-MUMNP-2007-FORM 2(GRANTED)-(1-11-2010).pdf

647-MUMNP-2007-FORM 2(TITLE PAGE)-(3-5-2007).pdf

647-mumnp-2007-form 2(title page)-(8-2-2010).pdf

647-MUMNP-2007-FORM 2(TITLE PAGE)-(GRANTED)-(1-11-2010).pdf

647-mumnp-2007-form 26(29-8-2007).pdf

647-MUMNP-2007-FORM 3(3-5-2007).pdf

647-MUMNP-2007-FORM 3(8-2-2010).pdf

647-MUMNP-2007-FORM 5(3-5-2007).pdf

647-MUMNP-2007-FORM 5(8-2-2010).pdf

647-MUMNP-2007-FORM PCT-ISA-237(8-2-2010).pdf

647-mumnp-2007-form-1.pdf

647-mumnp-2007-form-18.pdf

647-mumnp-2007-form-2.pdf

647-mumnp-2007-form-3.pdf

647-mumnp-2007-form-5.pdf

647-MUMNP-2007-PETITION UNDER RULE 137(8-2-2010).pdf

647-MUMNP-2007-REPLY TO EXAMINATION REPORT(8-2-2010).pdf

647-MUMNP-2007-SPECIFICATION(AMENDED)-(17-9-2010).pdf

647-MUMNP-2007-SPECIFICATION(AMENDED)-(8-2-2010).pdf

647-mumnp-2007-wo international publication report(3-5-2007).pdf

abstract1.jpg

form 2.doc


Patent Number 243710
Indian Patent Application Number 647/MUMNP/2007
PG Journal Number 45/2010
Publication Date 05-Nov-2010
Grant Date 01-Nov-2010
Date of Filing 03-May-2007
Name of Patentee ZF FRIEDRICHSHAFEN AG
Applicant Address 88038 FRIEDRICHSHAFEN
Inventors:
# Inventor's Name Inventor's Address
1 KUNZE, RALF KIRCHBREITE 12, 49152 BAD ESSEN
2 KNOPP, SOREN GROSSE HEIDE 26, 49179 OSTERCAPPELN
3 BUHL, MANFRED FELDSTRASSE 30, 49143 BISSENDORF
4 HELMS, HEINFRIED HORDINGHAUSER STRASSE 38, 49152 BAD ESSEN
PCT International Classification Number B06G7/00
PCT International Application Number PCT/DE05/002055
PCT International Filing date 2005-11-16
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 102004055961.9 2004-11-19 Germany