METHOD FOR MOUNTING A SLEEVE ON A STEERING GEAR

Abstract

A method of assembling a flexible sleeve on a steering gear, wherein the steering gear has a receptacle pin which protrudes axially in the direction of a longitudinal axis and from which a tie rod protrudes in a manner so as to be articulated relative to the longitudinal axis, and the sleeve has a flexible hose-shaped bellows which toward the gear has an annular connecting flange that is configured so as to be coaxial with a flange axis and toward the tie rod has an annular seal.

Claims

1.-7. (canceled)

8. A method for assembling a flexible sleeve on a steering gear, wherein the steering gear has a receptacle pin that protrudes axially in the direction of a longitudinal axis and from which a tie rod protrudes in a manner so as to be articulated relative to the longitudinal axis, and the sleeve comprises a flexible hose-shaped bellows which toward the gear has an annular connecting flange that is configured so as to be coaxial with a flange axis and toward the tie rod has an annular seal, comprising: moving the connecting flange in order to introduce the tie rod, offering up the connecting flange to the receptacle pin, plug-fitting the connecting flange on the receptacle pin, gripping the bellows in the gripper of a robotic manipulator, moving the gripper so as to introduce the tie rod through the connecting flange, inclining the gripper so as to incline the flange axis about a predefined inclination angle relative to the longitudinal axis, moving the gripper so as to offer up the connecting flange to the receptacle pin, detecting the impact of the connecting flange on the receptacle pin, moving the gripper so as to carry out tumbling and/or arcuate and/or translatory assembling movements of the connecting flange relative to the longitudinal axis, pressing the gripper in a force-controlled and/or position-controlled manner in the direction of the longitudinal axis against the receptacle pin, so as to plug-fit the connecting flange on the receptacle pin, until a predefined terminal position of the connecting flange on the receptacle pin is reached, and releasing the gripper from the sleeve.

9. The method of claim 8 wherein one or both of the gripper or the robotic manipulator is moved in one or both of a force-controlled or position-controlled manner.

10. The method of claim 8 wherein the gripper, at least in portions, encompasses the sleeve in a shape-supporting manner.

11. The method of claim 8 wherein, so as to thread the tie rod into the annular seal, a searching movement transverse to the direction of introduction is carried out when introducing the tie rod.

12. The method of claim 8 wherein, in order to detect the impact of the connecting flange on the receptacle pin, an increase of force in the force acting on the gripper is detected.

13. The method of claim 8 wherein during the assembling movement the connecting flange is plug-fitted on the receptacle pin as a function of the force acting in the direction of the longitudinal axis on the gripper.

14. The method of claim 8 wherein the connecting flange and the receptacle pin have communicating seat elements which mutually engage in a form-fitting manner.

Description

DESCRIPTION OF THE DRAWINGS

[0050] Advantageous embodiments of the invention will be explained in more detail hereunder by means of the drawings, in which specifically:

[0051] FIG. 1 shows a motor vehicle steering mechanism in a partial, schematic perspective illustration,

[0052] FIG. 2 shows a schematic, partially sectional illustration of the steering gear from FIG. 1 in the region of a sleeve,

[0053] FIG. 3 shows a first assembly state when carrying out the method according to the invention,

[0054] FIG. 4 shows a second assembly state when carrying out the method according to the invention,

[0055] FIG. 5 shows a third assembly state when carrying out the method according to the invention,

[0056] FIG. 6 shows a schematic illustration of coordinates of a motion path.

EMBODIMENTS OF THE INVENTION

[0057] Identical parts are always provided with the same reference signs in the various figures and are therefore also normally referred to or mentioned only once in each case.

[0058] FIG. 1 shows part of a motor vehicle steering mechanism, comprising a steering gear 1 which comprises a gear housing 11 which in the motor vehicle is connected to a body (not illustrated). A steering shaft (not illustrated) which for introducing manual steering commands can be connected to a steering wheel can be connected to an input shaft 12.

[0059] In an exemplary manner, a steering mechanism which is supported by auxiliary power and in which an auxiliary power drive 13 for assisting the manual steering torque introduced into the input shaft 12 is connected to the steering gear 1 is illustrated. The auxiliary power drive 13 preferably comprises an electric motor for coupling a motorized auxiliary power into a push rod 2.

[0060] A manual rotation of the input shaft 12, and also an introduction of a steering auxiliary torque by way of the auxiliary power drive 13, in the steering gear 1 is converted into a translatory movement of the push rod 2 which in the direction of a longitudinal axis L extends transversely to the direction of travel of the vehicle and to which in each case one tie rod 3 is articulated at each end by way of an inner joint 4 configured as a ball joint, as can be derived from FIG. 2.

[0061] The push rod 2, which in FIG. 1 is obscured by the gear housing 11, on both sideson the right and the left in FIG. 1is in each case guided out of the gear housing 11 by a receptacle pin 14, as can be seen in FIG. 2.

[0062] A rotation of the input shaft 12 and steering assistance by the auxiliary power drive 13 in the steering gear 1 is converted into a translatory movement of the push rod 2 to the right or the left along the longitudinal axis L, said movement by way of the two tie rods 3, as is indicated by double arrows in FIG. 1, being transmitted to the stub axles 31 in order to turn the steered wheels of the vehicle (not illustrated).

[0063] The push rod 2 as a gear element can comprise a rack which in a manner known per se meshes with a steering pinion that is attached to the input shaft 12, and/or a threaded spindleas is illustrated in an exemplary manner in FIG. 2when the auxiliary power drive 13 has a spindle drive with a spindle nut which can be rotatably driven in a motorized manner and in which the threaded spindle 2 engages.

[0064] The auxiliary power drive 13 can be omitted in a purely manual steering mechanism. The input shaft 12 can be omitted in a purely motorized steering mechanism without any direct manual steering intervention, for example in a so-called steer-by-wire steering system without any direct mechanical coupling between the steering wheel and the steering gear 1, and the steering angle is generated exclusively by, preferably electrically, actuating the auxiliary power drive 13.

[0065] One sleeve 5 which is preferably configured as a flexible molded elastic rubber part is attached to each of the two receptacle pins 14. The sleeve 5 has a connecting flange 51 having a flange axis F, said connecting flange 51 toward the gear being integrally configured on a bellows 52, an annular seal 53 which is likewise configured so as to be integral to the bellows 52 being attached to the gear-distal end of said bellows 52 toward the tie rod. The bellows 52 preferably has a plurality of encircling bellows creases 521. The connecting flange 51 is configured so as to be annual, having a circular flange opening 511 which is coaxial with the flange axis F.

[0066] In the assembly state according to FIG. 2, the connecting flange 52 by way of the flange opening 511 thereof is plug-fitted on the receptacle pin 14. The longitudinal axis L here is congruent with the flange axis F. The sleeve 5, from the flange opening 511 thereof to the beginning of the annular seal 53, has a first spacing A. A second spacing a is provided from the flange opening 511 to the beginning of the gripper 6, or of the mutually opposite grippers, respectively, thus closer toward the flange opening 511. The second spacing a is preferably smaller than or equal to of the first spacing A, the second spacing is further preferably smaller than or equal to of the first spacing A, and the second spacing a is further preferably larger than of the first spacing A. The receptacle pin 14 furthermore has a diameter D. The second spacing a is preferably in a range between 20% to +20% of the diameter D of the receptacle pin 14.

[0067] FIG. 3 shows a first assembly state when carrying out the method according to the invention. A gripper 6 between the gripping jaws 61 and 62 thereof here encompasses the bellows 52 in a shape-supporting manner. To this end, the gripping jaws 61 and 62 on the inside are shaped so as to be complementary to the bellows creases 521 so that the sleeve 6 is aligned in a form-fitting manner in the gripper 6 and so as to be spatially defined longitudinally as well as transversely to the flange axis F.

[0068] In FIG. 3, the connecting flange 52 is partially threaded onto the tie rod 3, wherein the tie rod 3 through the flange opening 511 plunges into the bellows 52 but does not exit again through the annular seal 53. In order for the sleeve 5 to be completely threaded on the tie rod 3, the gripper 6 is made to move in an oscillating searching movement that is transverse to the flange axis F, thus toward the top and the bottom in the drawing plane, for example, and additionally or alternatively out of and into the drawing plane, as is indicated by the intersecting arrows, in other words in the y direction and/or the z direction which are perpendicular to the direction of the longitudinal axis L.

[0069] On account of the gripper 6 being moved toward the receptacle pin 14, the annular seal 53 is moved toward the free end of the tie rod 3. When the cross section of the tie rod 3 is congruent with the opening cross section of the annular seal 53, the tie rod 3 passes through the annular seal 53 so that the assembly state shown in FIG. 4, in which the sleeve 5 is completely threaded onto the tie rod 3, is reached. Should the end of the tie rod 3 impact or catch from the inside on the annular seal 53 or the bellows 52, said tie rod 3 is released on account of the oscillating searching movement and will pass through toward the outsidetoward the right in FIG. 3as soon as congruence between the open opening cross section of the annular seal 53 and the cross section of the tie rod 3 is established in the course of the searching movement, and the sleeve 5 is completely threaded on. The searching movement here can comprise linear, arcuate or orbiting movement components of the annular seal 53 that are transverse to the flange axis F.

[0070] The gripper 6 from the assembly position of FIG. 4 is inclined such that the flange axis F is inclined about a predefined inclination angle (alpha) relative to the longitudinal axis L, as is illustrated in FIG. 5. The sleeve 5 here, conjointly with the tie rod 3 received therein, is inclined relative to the longitudinal axis L of the receptacle pin 14. The inclination takes place about an inclination axis which runs transversely through the longitudinal axis L, preferably through the inner joint 4, wherein the tie rod 3 in the inner joint 14 can be angled relative to the tie rod 2the rack or threaded spindle. In this assembly state, the connecting flange 51 is oblique in relation to the receptacle pin 14 at the inclination angle (alpha). The flange axis F can preferably be at an acute inclination angle (alpha) in relation to the longitudinal axis L.

[0071] The sleeve 4 from the assembly position of FIG. 4 can first be inclined and then be moved to the receptacle pin 14 by moving the gripper 6 until the connecting flange 51 impacts obliquely on the receptacle pin 14, as is illustrated in FIG. 5. Alternatively, the offering-up can take place first and the inclining can take place thereafter, or else the offering-up and the inclining can take place in a combined movement, until the position shown in FIG. 5 is reached.

[0072] The impact can be detected by a force-controlled movement of the gripper 6, wherein it is continually monitored which counter force is acting on the gripper 6. Said counter force steeply increases when the sleeve 5 impacts on the receptacle pin 14.

[0073] Subsequently, or already during the offering-up prior to the impact, the sleeve 5 by the gripper 6 is brought into a tumbling and/or translatory and/or arcuate assembling movement about the longitudinal axis L. A point X on the flange axis F, which as illustrated in FIG. 5 has a radial spacing in relation to the longitudinal axis L, for example in an y-z plane which is perpendicular to the longitudinal axis L, here can perform a motion path which is similar to a Lissajous curve, as is shown in a schematic view in a plane transverse to the longitudinal axis L in FIG. 6.

[0074] During the aforementioned assembling movement, force-controlled and/or position-controlled pressing of the gripper 6 in the direction of the longitudinal axis L against the receptacle pin 14, in order to plug-fit the connecting flange 51 on the receptacle pin 51, takes place according to the invention until the terminal position of the connecting flange 51 on the receptacle pin 14 shown in FIG. 2 is reached. The connecting flange 51 while going through the assembling movement assumes a multiplicity of different relative positions in relation to the receptacle pin 14 and here is simultaneously pressed against the receptacle pin 14. As soon as a relative position which is suitable for plug-fitting is passed here, the contact pressure force exerted ensures that the flange opening 511 of the connecting flange 51 at the end side is forced onto the receptacle pin 14, in other words the receptacle pin 14 enters the flange opening 511.

[0075] The forcing of the connecting flange 51 onto the receptacle pin 14 can be detected by way of a brief reduction of the counter force which acts on the gripper 6 and acts counter to the contact pressure force exerted and which for force control is measured by the gripper 6 or the robotic manipulator. The assembling movement can then continue to be carried out to the full extent or a partial extent, for example as a pure tumbling movement about the longitudinal axis L, or else be completely switched off once the connecting flange 51 has been aligned so as to be coaxial with the longitudinal axis L.

[0076] Proceeding from the position when forcing, the connecting flange 51 in the direction of the longitudinal axis L can be plug-fitted further on the receptacle pin 14, for example in a position-controlled manner by a predefined distance in the direction of the longitudinal axis L, such that an inner seat configured in the flange opening 511 in the fixing position can be positioned on an outer seat configured on the receptacle pin 14 in the required terminal position.

[0077] In order for a form-fit which is effective in the direction of the longitudinal axis L to be formed in the terminal position, a form-fit element 15 which encircles the cylindrical seat of the receptacle pin 14 and which in the example is configured as a radially projecting rib can latch in a communicating, encircling groove on the inside of the connecting flange 51.

[0078] The releasing of the gripper 6 from the sleeve 5 takes place upon reaching the predefined terminal position. In order for the sleeve 5 to be released, gripping jaws 61 and 62 of the gripper 6 are diverged, for example, so that the gripper 6 can be removed from the completely assembled sleeve 5.

LIST OF REFERENCE SIGNS

[0079] 1 Steering gear [0080] 11 Gear housing [0081] 12 Input shaft [0082] 13 Auxiliary power drive [0083] 14 Receptacle pin [0084] 15 Form-fit element [0085] 2 Push rod [0086] 3 Tie rod [0087] 31 Stub axle [0088] 4 Inner joint [0089] 5 Sleeve [0090] 51 Connecting flange [0091] 511 Flange opening [0092] 52 Bellows [0093] 521 Bellows crease [0094] 53 Annular seal [0095] 6 Gripper [0096] 61,62 Gripping jaws [0097] F Flange axis [0098] L Longitudinal axis [0099] A First spacing [0100] a Second spacing [0101] D Diameter of the receptacle pin 14