METHOD FOR MOUNTING AN ANNULAR SEALING ELEMENT

Abstract

A method for assembling an annular seal element, formed by a sealing cord which runs around an opening on a seal receptacle which runs around on the outside of a component. The method includes introducing two assembly fingers into the opening of the annular seal element, stretching the annular seal element by moving the assembly fingers apart from one another, with the formation of a cord portion of the sealing cord, the cord portion being freely tensioned between the assembly fingers, placing the freely tensioned cord portion onto the seal receptacle in a contact region, applying the annular seal element, by way of its opening, onto the seal receptacle, and removing the assembly fingers from the annular seal element. The assembly fingers are moved so as to follow the profile of the seal receptacle, to travel around the seal receptacle in opposite directions.

Claims

1-10. (canceled)

11. A method for assembling an annular seal element, which is formed by a sealing cord which runs around an opening, on a seal receptacle which runs around on the outside of a component, comprising: introducing two assembly fingers into the opening of the annular seal element, stretching the annular seal element by moving the assembly fingers apart from one another, with the formation of a cord portion of the sealing cord, said cord portion being freely tensioned between the assembly fingers, placing the freely tensioned cord portion onto the seal receptacle in a contact region, applying the annular seal element, by way of its opening, onto the seal receptacle, and removing the assembly fingers from the annular seal element, wherein, for the application of the annular seal element, the assembly fingers are moved so as to follow the profile of the seal receptacle, so as to travel around the seal receptacle in opposite directions.

12. The method of claim 11 wherein during the traveling-around operation, the assembly fingers are moved at a substantially constant spacing from the seal receptacle.

13. The method of claim 11 wherein the assembly fingers are attached to robot manipulators which are configured to be movable independently of one another, along multiple axes.

14. The method of claim 11 wherein at least one assembly finger has a retaining device in which the sealing cord is positioned during the stretching and traveling-around operations.

15. The method of claim 11 wherein, for removal, the assembly fingers are tilted relative to the seal receptacle and the annular seal element.

16. The method of claim 11 wherein the seal receptacle is formed by a groove which runs around on the outside.

17. The method of claim 11 wherein, during the stretching operation, the annular seal element extends substantially parallel to a stretching plane.

18. The method of claim 17 wherein, during the traveling-around operation, the stretching plane is tilted toward the receiving plane.

19. The method of claim 11 wherein the seal receptacle extends substantially parallel to a receiving plane.

20. The method of claim 11 wherein, before the placing-on of the freely tensioned cord portion, the stretching plane is inclined relative to the receiving plane.

Description

DESCRIPTION OF THE DRAWINGS

[0037] Below, advantageous embodiments of the invention are described in more detail on the basis of the drawings. In detail:

[0038] FIG. 1 shows a schematic perspective view of a motor vehicle steering system,

[0039] FIG. 2 shows a schematic perspective view of a transmission (steering assistance transmission) of a motor vehicle steering system as per FIG. 1,

[0040] FIG. 3 shows a longitudinal section through the transmission as per FIG. 2,

[0041] FIGS. 4 to 12 show successive method steps during the assembly of an O-ring on a transmission as per FIGS. 2 and 3.

EMBODIMENTS OF THE INVENTION

[0042] In the various figures, the same parts are always provided with the same reference designations, and will therefore generally also be named or mentioned only once in each case.

[0043] FIG. 1 schematically illustrates a motor vehicle steering system 100, wherein a driver can input a corresponding steering torque (steering moment) as steering command into a steering shaft 1 using a steering wheel 102. The steering moment is transmitted via the steering shaft 1 to a steering pinion 104, which meshes with a rack 106, which then in turn transmits the prescribed steering angle to the steerable wheels 110 of the motor vehicle by means of a displacement of the track rods 108.

[0044] An electrical power assistance means may be provided in the form of a power assistance means 112 coupled at the input side to the steering shaft 1, of a power assistance means 114 coupled to the pinion 104, and/or of a power assistance means 116 coupled to the rack 106. The respective power assistance means 112, 114 or 116 couples an auxiliary torque into the steering shaft 1 and/or the steering pinion 104 and/or an auxiliary force into the rack 106, whereby the driver is assisted in performing steering work. The three different power assistance means 112, 114 and 116 illustrated in FIG. 1 show possible positions for the arrangement thereof.

[0045] Normally, only a single one of the positions shown is occupied by a power assistance means 112, 114 or 116. The auxiliary torque or the auxiliary force which is to be imparted by the respective power assistance means 112, 114 or 116 for the purpose of assisting the driver is determined to take into consideration a steering moment input by the driver and detected by a torque sensor 118. Alternatively or in combination with the introduction of the auxiliary torque, an additional steering angle can be introduced into the steering system by the power assistance means 112, 114, 116, said additional steering angle being added to the steering angle imparted by the driver via the steering wheel 102.

[0046] The steering shaft 1 comprises, at the input side, an input shaft 10 connected to the steering wheel 102 and, at the output side, an output shaft 12 connected to the rack 106 via the steering pinion 104. The input shaft 10 and the output shaft 12 are coupled to one another in a rotationally elastic manner by way of a torsion bar 119 (see FIG. 3), which is not shown in FIG. 1. Thus, a torque input into the input shaft 10 by a driver via the steering wheel 102 always leads to a relative rotation of the input shaft 10 with respect to the output shaft 12 whenever the output shaft 12 does not rotate exactly synchronously with respect to the input shaft 10. This relative rotation between the input shaft 10 and the output shaft 12 can be measured by way of a rotational angle sensor and, correspondingly, on the basis of the known torsional stiffness of the torsion bar, a corresponding input torque relative to the output shaft 12 can be determined. In this way, through the determination of the relative rotation between the input shaft 10 and the output shaft 12, the torque sensor 118 is formed. Such a torque sensor 118 is known in principle and can for example be realized by means of an electromagnetic sensor arrangement, as described further below, or by another means of measurement of the relative rotation.

[0047] Correspondingly, a steering moment imparted to the steering shaft 1 or to the input shaft 10 by the driver via the steering wheel 102 will give rise to the introduction of an auxiliary torque by one of the power assistance means 112, 114, 116 only if the output shaft 12 is rotated relative to the input shaft 10 counter to the torsional resistance of the torsion bar.

[0048] The torque sensor 118 can also alternatively be arranged at the position 118, wherein then the division of the steering shaft 1 into input shaft 10 and output shaft 12 and the rotationally elastic coupling by way of the torsion bar are correspondingly present at a different position in order, from the relative rotation of the output shaft 12 coupled to the input shaft 10 via the torsion bar, to be able to determine a relative rotation and thus correspondingly an input torque and/or an auxiliary torque to be introduced.

[0049] The steering shaft 1 as per FIG. 1 furthermore comprises at least one cardanic joint 120, by means of which the profile of the steering shaft 1 in the motor vehicle can be adapted to the spatial conditions.

[0050] In the example illustrated, the power assistance means 114 comprises a transmission 2, which forms a steering assistance transmission, and is illustrated in FIG. 3 in longitudinal section along the longitudinal axis L of the steering shaft 1 and in FIG. 2 in a perspective view in a partially assembled state.

[0051] The transmission 2 comprises a component 21, which forms a first housing part which comprises a shoulder 22 which, in the illustration of FIG. 3, is directed toward the left in the axial direction of the longitudinal axis L, on which shoulder there is configured a groove 23 in the form of an outwardly open groove, that is to say a groove which is radially open with respect to the longitudinal axis L, said groove running around the component 21 with respect to the longitudinal axis L.

[0052] The component 21 engages by way of the shoulder 22 into a corresponding housing opening 24 of a second housing part 25.

[0053] In the closed state shown in FIG. 3, the housing parts 21 and 25 are connected to one another by fastening elements 26, for example screws or bolts. A radially peripheral gap is located between the groove 23 and the inner side of the housing opening 24. An O-ring 3 is inserted into the peripheral groove 23 in a positively locking manner and in this case projects to such an extent radially that said O-ring lies radially from the inside against the inner side of the housing opening in a sealing manner.

[0054] FIGS. 2 and 3 show how the steering shaft 1 is mounted in the housing parts 21 and 25 so as to be rotatable about the longitudinal axis L and passes through the housing. A transmission wheel 130, for example a worm wheel of the power assistance means 114, which is accommodated in the housing in a sealed manner, is attached on the steering shaft 1 in a rotationally fixed manner.

[0055] FIGS. 4 to 12 schematically illustrate individual steps of the assembly of the O-ring 3 in the groove 23 of the component 21. The component 21 is schematically shown in an axial view in the direction of the longitudinal axis L, specifically corresponding to a view from the left as per FIG. 3.

[0056] The O-ring 3 is formed by a sealing cord 31 composed of a rubber-elastic material, said cord running around an opening 32.

[0057] An assembly finger 41 and 51, which is configured in the form of a cylindrical pin and in each case comprises, in the front region, a peripheral retaining groove 42, 52 as retaining device, is in each case fastened to a robot manipulator 4 and 5. The robot manipulators 4, 5 permit a multi-axis movement of the assembly fingers 41, 51 in space, specifically at least translationally in the x, y and z directions, and also rotationally about axes of rotation r which, in the example, are angled in relation to the longitudinal extent of the assembly fingers 41, 51.

[0058] FIG. 4 shows how the one assembly finger 51 is dipped in an introduction direction into the opening 32 of the O-ring 3, and subsequently the other assembly finger 41, such that, as per FIG. 5, both assembly fingers 41, 51 are located in the opening, specifically adjacently at such a distance that they initially do not touch the sealing cord 31.

[0059] Subsequently, as shown in FIG. 6, the assembly fingers 41, 51 are moved apart from one another in the direction of the arrows, that is to say are distanced relative to one another by the robot manipulators 4, 5 until the sealing cord 31 is received in the retaining grooves 42, 52 in a positively locking manner. In this case, the O-ring 3 is stretched in an oval-shaped manner in such a way that at least one freely tensioned cord portion 31a is formed between the assembly fingers 41, 51.

[0060] The O-ring 3 is now stretched in a stretching plane which is inclined relative to the receiving plane, parallel to which receiving plane the groove 23 runs and the normal direction of which is identical to the longitudinal axis L.

[0061] Subsequently, in the stretched state, the O-ring 3 is moved in a translational and transverse manner toward the longitudinal axis L as a result of synchronized movement, as shown in FIG. 7, until the sealing cord 31, starting with the inner side of the cord portion 31a, contacts the groove 23 in a contact region 31b and is in this case inserted from the outside into said groove, as illustrated in FIG. 8.

[0062] FIG. 8 shows the placing of the O-ring 3 onto the seal receptacle 23.

[0063] Hereafter, the assembly fingers 41, 51 are moved relative to the component 21 so as to follow the profile of the groove 23 at a spacing, as indicated by the dashed arrows in figures 8 and 9. As a result, the groove 23 is traveled around in opposite directions. As a result, the contact region 31b, in which the sealing cord 31 has been inserted in the groove 23 in a positively locking manner, is continually increased over the periphery of the component 21 until the peripheral groove 23 is located completely in the opening 32 of the O-ring 3, as illustrated in FIG. 10. FIG. 10 shows the end point during the traveling-around operation, with the free cord portion 31c which remains between the assembly fingers 41, 51 being retained at a spacing parallel to the groove 23.

[0064] During the phases shown in FIGS. 8 to 10, it is possible to execute a simultaneous tilting movement of the robot manipulators 4 and 5 in order to pivot the stretching plane of the O-ring 3 in the direction of the receiving plane of the groove 23 until the two planes lie parallel to each other in the state shown in FIG. 10.

[0065] For removal from the O-ring 3, the assembly fingers 41, 51 are tilted in an oppositely rotating manner about the axes of rotation r which lie parallel to an assembly plane, which is defined, by the profile of the sealing cord 31c, between the assembly fingers 41, 51 and the contact region 31b. As a result, the assembly fingers 41, 51 are levered, to a certain extent, out of the interspace between the groove 32 and the cord portion 31c of the O-ring 3 and removed from the O-ring 3, with the sealing cord 31 springing out of the retaining grooves 42, 52 and then sitting completely in the peripheral groove 23.

[0066] Said end state of the assembly is illustrated in FIG. 12. Component 21 can then be inserted into the housing part 25.

LIST OF REFERENCE DESIGNATIONS

[0067] 1 Steering shaft

[0068] 10 Input shaft

[0069] 12 Output shaft

[0070] 100 Motor vehicle steering system

[0071] 102 Steering wheel

[0072] 103 Steering gear

[0073] 104 Steering pinion

[0074] 106 Rack

[0075] 108 Track rod

[0076] 110 Wheel

[0077] 112 Power assistance means

[0078] 114 Power assistance means

[0079] 116 Power assistance means

[0080] 118 Torque sensor

[0081] 118 Torque sensor

[0082] 119 Torsion bar

[0083] 120 Joint

[0084] 130 Transmission wheel

[0085] 2 Transmission

[0086] 21 Component (housing part)

[0087] 22 Shoulder

[0088] 23 Groove

[0089] 24 Housing opening

[0090] 25 Housing part

[0091] 3 Annular seal element/O-ring

[0092] 31 Sealing cord

[0093] 31a Cord portion

[0094] 31b Contact region

[0095] 31c Cord portion

[0096] 32 Opening

[0097] 4, 5 Robot manipulator

[0098] 41, 51 Assembly finger

[0099] 42, 52 Retaining groove

[0100] L Longitudinal axis