WO2008064818A1 - Shaft assembly of an electromotoric auxiliary drive, method for securing a functional element onto a shaft, and an expander ring - Google Patents

Abstract

The invention relates to a a shaft assembly of an electromotoric auxiliary drive for vehicles having at least one shaft and at least one functional element which is secured onto the shaft by axial clamping using at least one clamping element. The clamping element is an expander ring with a ring body which clasps around the shaft with a wall section and which supports itself on the shaft with a first edge area, and which directly or indirectly abuts against the at least one functional element with a second edge area opposite the first edge area.

Description

 Shaft arrangement of an electric motor auxiliary drive, method for securing a functional element on a shaft and spreader

The invention relates to a shaft assembly of an electromotive auxiliary drive for vehicles, with at least one shaft and with a secured on this shaft by axial clamping functional element according to the preamble of claim 1.

Furthermore, the invention relates to a method for axially securing at least one functional element on a shaft of an electric motor auxiliary drive for vehicles according to the preamble of claim 15 and to a spreader according to the preamble of claim 22.

In particular, in small motors electric auxiliary drives for vehicles, it is common and necessary to secure functional elements, ie for example bearing elements, such as provided on a shaft, eg armature shaft inner bearing rings of ball bearings axially and backlash on the shaft. For this purpose, it is common in anchor shafts for small engines for vehicle auxiliary drives in practice, in addition to an example formed by a retainer ring or C-clip axial support against which the bearing ring abuts with a front side, to use a metal bush, against the other end face of the bearing ring is pressed and anchored under high radial force on a groove provided in the shaft by crimping or crimping. The disadvantage here is, inter alia, that it is through the high radial force necessary for crimping can cause the shaft to bend.

For axial securing of a bearing ring on the armature shaft of a small electric motor is also known (DE 40 39 453 Al) to provide on the armature shaft an axially acting clamping element in the form of a surrounding the armature shaft compression spring, which is supported at one end to the armature shaft and with her another end bears against the bearing element, so that it is clamped between the compression spring and provided on the armature shaft and axially supported on this armature shaft sleeve. However, this known axial securing of the inner bearing ring of a ball bearing is constructive and very expensive in terms of assembly.

The object of the invention is to show a shaft arrangement, which ensures a reliable and in particular permanent axial fixation of a functional element on a shaft with reduced, constructive effort. To solve this problem, a shaft assembly according to claim 1 is formed.

A method for securing a functional element on a shaft according to the invention according to the claim 15 is formed. An expansion ring for use in the arrangement according to the invention and in the method according to the invention is the subject of claim 22.

In the invention, the axial securing of the respective functional element, which is for example a bearing element, for example, the inner bearing ring of a ball or needle bearing, in a particularly simple manner by placing the spreader on the shaft, by axially securing the Spreizringes on the shaft and by subsequent permanent deformation of the at least one, the shaft enclosing and Wall section of the expansion ring in a waisted shape. In this case, an increase in the axial dimension of the expansion ring and thus an axial spreading of this ring, for the backlash-free axial securing or bracing of the respective functional element on the shaft. The shaft is, for example, the armature shaft of the small motor of the electric auxiliary drive for vehicles or another wave of such auxiliary drive. The electric auxiliary drive is eg a

Windscreen wiper drive, a drive for an electric seat adjustment, a drive of a power window etc.

The axial securing of the expansion ring on the respective shaft as well as the subsequent spreading or deformation of the expansion ring carried by a uniformly distributed on the circumference of the spreader radial application of force. In this case, it is not necessary that radial forces are introduced directly onto the shaft, which u.a. also the risk of bending the shaft is avoided.

The material used for the spreader is selected so that the spreader is deformed during spreading and permanently exerts a permanent clamping force on the respective functional element directly or indirectly, so that even during prolonged operation, for example due to temperature changes length changes are compensated by the spread spreader, i. the desired backlash axial securing of the respective functional element in all operating conditions, even after a long period of operation exists. As a material for the expansion ring is particularly suitable a metallic material, preferably steel.

With the construction according to the invention tolerances of the shaft and / or the respective functional element are further compensated in a particularly simple manner when spreading the expanding ring. Further developments are the subject of the dependent claims. The invention will be explained in more detail below with reference to the figures of an embodiment. Show it:

Figure 1 is a partial representation of the armature shaft of a small motor of an electric motor auxiliary drive, together with a patch on the armature shaft spreader for fixing a ball bearing and the inner bearing ring, before spreading the Spreizringes.

2 shows a section along the line I - I of Figure 1;

Fig. 3 u. 4 representations like figures 1 and 2, but after the

Fixing the ball bearing on the armature shaft or after spreading the Spreizringes;

Fig. 5 in positions a - c the spreader in side view and in various states during assembly;

Fig. 6 in positions A - C the expanding ring respectively in section, in the positions A - C of Figure 5 corresponding states during assembly;

Fig. 7 u. 8 representations like figures 1 and 3 in another

Embodiment of the invention.

In the figures, 1 is the armature shaft of a small electric motor, which is part of an electric motor auxiliary drive for vehicles. On the armature shaft 1 u.a. the rotor 2 consisting of the laminated core and the armature winding and in the embodiment shown in Figures 1 - 4 also provided a ball bearing 3, which is part of a bearing assembly, not shown, for the armature shaft 1.

The ball bearing 3 consists in a known manner of an inner bearing ring 4, of an outer bearing ring 5 and arranged between these balls 6. With the inner bearing ring 4, the ball bearing 3 is mounted on the armature shaft 1 fits and play. For axial and backlash-free backup of the ball bearing 3, the inner bearing ring 4 is located with an end face against a provided on the armature shaft axial support 7, which is formed in the illustrated embodiment by an engaging in a circumferential groove of the armature shaft 1 circlip or C-clip. To secure the ball bearing 3 on the armature shaft 2, a spreader ring 8 is further provided which abuts against the support 7 facing away from the end face of the bearing ring 4 and this against the support 7 axially, that is pressed in the axial direction of the armature shaft. As well as the support 7 and the spreader ring 8 is made of a metallic material, preferably made of steel, in accordance with Figures 5 and 6 with an initially open before mounting annular body (opening 9), for example, by punching and roll forming from the metallic Flat material is made in one piece, with a not yet mounted spreader 8 partially annular, a Spreizringachse SA enclosing wall section 8.1 and in the direction of Spreizringachse SA, ie radially inwardly directed or angled and spaced apart in the direction of the axis SA edge regions 8.2 and 8.3 , When not yet finally mounted spreader 8 of the wall portion 8.1 is curved barrel-like on its outer surface facing away from the axis SA in the broadest sense, ie shaped so that this wall section 8.1 in sectional planes, which include the Spreizringachse SA or the axis of the shaft 1, on the inside concave and convex on the outside. Furthermore, in the illustrated embodiment in the wall section 8.1 distributed around the axis SA a plurality of extending in the direction of this axis slot-shaped openings 10 are provided so that the peripheral wall 8.1 of the spreader 8 ultimately consists of a plurality of formed between the openings or slots 10 webs 11.

For the expansion ring 8 in the armature shaft 1, two circumferentially open and the armature shaft axis concentrically enclosing grooves 12 and 13 are provided which have an axial distance from each other in the direction of the armature shaft axis, which is equal to or approximately equal to the distance that the edge areas 8.2 and 8.3 in the direction of the Spreizringachse SA own each other. The width of the groove 12, which has a greater axial distance from the support 7, is equal to or slightly larger than the material thickness of the sheet material used for the production of the locking ring 8 and thus equal to or slightly larger than the material thickness of the spreader 8 in the illustrated embodiment in the area of margins 8.2 and 8.3.

The support 7 closer groove 13 has in the illustrated embodiment, a relation to the groove 12 slightly larger width and beyond an axial distance from the support 7, which is slightly smaller than the axial dimension of the inner bearing ring 4. This ensures that after sliding the ball bearing 3 on the armature shaft 1 with the bearing surface 4 abutting against the support 7 bearing ring 4 with the other end side slightly overlaps the groove 13, which is not covered by the bearing ring 4 region of the groove 13 but still has a width that at least equal, but preferably slightly larger than the material thickness of the spreader. 8

To secure the patch on the armature shaft 1 and the bearing ring 4 against the support 7 supporting ball bearing 3 of the open spreader 8 (position a of Figures 5 and 6), for example, axially mounted on the armature shaft 1, so that an edge region, for example, the edge region 8.2 in the region of the groove 12 and the other edge region, for example, the edge region 8.3 come to lie in the region of the groove 13. With a tool enclosing the expansion ring 8, it is first deformed into a closed ring by uniform radial or circular action of force (arrows K of FIG. 2). The flanks of the opening 9, ie the opening 9 delimiting surfaces come at the end of this closing operation against each other to the plant and thereby cause a mechanical limitation of the deformation during closing and the concomitant reduction of the inner diameter of the spreader 8, so that during the closing process a defined Spreizringdurchmesser results that prevents radial contact with the shaft 1, but ensures that the sections 8.2 and 8.3 are immersed in the grooves 12 and 13 in the required manner. The opening 9 or the circle segment of the open expansion ring 8 formed by this opening are chosen such that when closing the expansion ring exactly the desired diameter for the closed expansion ring is achieved.

After this closing of the expansion ring 8, the edge regions 8.2 and 8.3 are each deformed to a circumferential wall 8.1 radially inwardly, closed annular portion, with an inner ring diameter which is smaller than the outer diameter of the armature shaft 1. Each so deformed edge region 8.2 and 8.3 is received in a groove, namely the edge region 8.2 in the groove 12 and the edge region 8.3 in the groove 13, but it in neither of the two grooves 12 and 13 to a radial abutment of the respective edge region 8.2 and 8.3 comes at the base diameter under the action of radial force on the shaft 1. In the position b of Figures 5 and 6 each deformed to a closed ring spreader 8 is shown. Figures 1 and 2 show the spreader in this closed, but not yet spread state on the armature shaft. 1

In a further method step, the peripheral wall 8.1 of the closed spreader ring 8 is then deformed in such a way that the tool enclosing the spreader ring 8 is uniformly deformed by uniform radial or circular force action (arrows K of FIG. 2), that this peripheral wall 8.1 is fitted on its outer surface, the depth or depth However, the dimension of this sidecut is smaller than the degree of bulging, the (dimension) of the wall section 8.1 with closed, but not yet gedrücktem spreader 8 has. The measure of the waisting or the bulge is in each case the difference of the radii, which has the closed expansion ring 8 approximately in the middle between the edge regions 8.2 and 8.3 or at these edge regions. By the deformation or the over-pressing of the expansion ring 8 results in an increase in the axial distance between the annular edge regions 8.2 and 8.3 and thus a spreading effect in the axial direction of the armature shaft 1 in the form that the deformed, ie axially spread spreader 8 with his against the Bearing ring 4 adjacent edge region 8.3 this bearing ring between itself and the support 7 fixed by bracing. Figures 5 and 6 show in the position c the deformed for spreading spreader again in a single representation.

The deformation of the expansion ring 8 is limited by the fact that the wall portion 8.1 comes against the armature shaft 1 between the two grooves 12 and 13 to the plant. By waisted shape of the spread spreader 8 and by the concerns of the wall section 8.1 against the armature shaft 1 and an unwanted reshaping of the spreader 8 is effectively prevented. By design, there is a self-locking in several ways. This not only consists in limiting the deformation or the reduction in diameter when closing the spreader ring 8, but also prevents the subsequent spreading of the spreader ring 8 overpressure of the wall section 8.1 beyond a predefined amount, and / or that the spread spreader 8 can relax independently by axial forces in operation in an undesirable manner.

With the expansion ring 8 not only reliable axial and play-free fixation of the ball bearing 3 on the armature shaft 1 is achieved, but the use of the expansion ring 8 also has other significant advantages, in particular to the effect that in the fixation of the ball bearing 3 with the spreader. 8 No radial forces are introduced to the armature shaft 1 and thus in particular a possible bending of the armature shaft 1 is avoided. When spreading the Spreizringes 8 takes place only an axial force on the armature shaft 1. Further is built by the elasticity of the spread spreader 8 a permanent frontal force on the bearing ring 4.

Figures 7 and 8 show an embodiment in which on the armature shaft 1 between the spreader ring 8 and the ball bearing 3 further functional elements are provided, namely a magnetic ring 14 for driving at least one responsive to a magnetic field sensor of an electric control and between this magnetic ring In this embodiment, therefore, the magnetic ring 14, the bush 15 and the bearing ring 4 of the ball bearing 3 between the spread spreader 8 and the support 7 are clamped axially on the armature shaft 1, namely in the same way as described above in connection with FIGS. 1-6.

FIG. 7 shows the state before the axial spreading of the expanding ring 8 or before the overpressing of the peripheral wall 8.1. 8 shows the state after the axial spreading of the expansion ring 8. The two grooves 12 and 13 are in this embodiment at the armature shaft 11 turn where also the spreader 8 and its edge areas 8.2 and 8.3 are provided.

The invention has been described above by means of an embodiment. It is understood that numerous changes and modifications are possible without thereby departing from the inventive idea underlying the invention.

Above, it was assumed that the open spreader ring is placed axially on the armature shaft 1. Basically, with appropriate design of the opening 9 and the possibility of the spreader 8 with this opening 9 laterally or radially to the respective shaft, eg put on the armature shaft 1. In this case, the width of the opening 9 is at least equal to the outer diameter of the shaft.

LIST OF REFERENCE NUMBERS

1 armature shaft

2 rotor

3 ball bearings

4 inner bearing ring

5 outer bearing ring

6 ball

7 axial support

8 spreader ring

8.1 peripheral wall of the ring body

8.2, 8.3 border area

9 opening of the open expansion ring. 8

10 slot

11 footbridge

12, 13 groove

14 magnetic ring

15 socket

K radial force

SA axis of the expansion ring 8

Claims

claims 1. shaft assembly of an electric motor auxiliary drive for vehicles, with at least one shaft (1) and with at least one functional element (3, 14, 15) which is axially secured by axial bracing using at least one tensioning element on the shaft (1), characterized in that the clamping element is a spreader ring (8) which encloses the shaft (1) with at least one wall section (8.1), is axially supported on the shaft (1) with a first edge region (8.2) and axially with respect to the first one offset edge region (8.3) directly or indirectly against the at least one functional element (4, 14, 15) is applied, and that for bracing the functional element (4, 14, 15) by axial spreading of the expansion element (8) of the at least one wall section (8.1) from an original shape in which this wall portion (8.1) in sectional planes, which include a Spreizringachse (SA) or an axis of the shaft (1), on the inside concave and is formed convex on the outside, is permanently deformed by overpressing in a waisted shape. 2. Shaft arrangement according to claim 1, characterized in that the shaft is the armature shaft (1) of a small electric motor of the electric auxiliary drive. 3. Shaft arrangement according to claim 1 or 2, characterized in that the functional element is provided on the shaft (1) bearing element, for example, the inner bearing ring (4) of a needle or ball bearing (3). 4. Shaft arrangement according to one of the preceding claims, characterized in that on the shaft (1) has an axial support (7), is provided for example in the form of a collar or a support ring, and that the at least one functional element (4, 14, 15) between this support (7) and the axially spread spreader (8) is clamped. 5. Shaft arrangement according to one of the preceding claims, characterized in that the at least one functional element is provided by the axial clamping play-free on the shaft (1). 6. shaft assembly according to one of the preceding claims, characterized in that the Spreizringes (8) with the waisted wall portion (8.1) abuts against the shaft (1) and this is immediately adjacent. 7. Shaft arrangement according to one of the preceding claims, characterized in that the depth of the sidecut of the wall portion (8.1) after spreading is smaller than the extent of the bulge formed by the original shape of this wall portion (8.1) before spreading. 8. Shaft arrangement according to one of the preceding claims, characterized in that the first edge region (8.2) for axially supporting the expansion ring (8) engages in a groove (12) of the shaft. 9. Shaft arrangement according to one of the preceding claims, characterized in that the second edge region (8.3) of the expansion ring (8) is received in a further groove (13) of the shaft (1). 10. Shaft arrangement according to one of the preceding claims, characterized in that the spread spreader (8) surrounds the shaft (1) without radial force or substantially without radial force. 11. Shaft arrangement according to one of the preceding claims, characterized in that the deformed by overpressing wall portion (8.1) by a plurality of Spreizstegen (11) is formed. 12. Shaft arrangement according to one of the preceding claims, characterized in that the spreader ring (8) consists of a permanently deformable material. 13. Shaft arrangement according to one of the preceding claims, characterized in that the spreader ring (8) made of metal, preferably made of steel. 14. Shaft arrangement according to one of the preceding claims, characterized in that the spreader ring is made of a flat material by stamping and forming. 15. A method for axially securing at least one functional element (4, 14, 15) on a shaft (1) of an electric motor auxiliary drive for vehicles by axial bracing of the at least one functional element (4, 14, 15) between an axial support (7) and a a permanent axial clamping force generating clamping element, characterized in that on the shaft (1) forming a clamping element spreader ring (8) and on the shaft (1) axially with a first edge region (8.2) is secured so that the spreader (8 ) surrounds the shaft (1) with at least one wall section (8.1) and a second edge region (8.3) adjacent to the functional element (4, 14, 15), and that for bracing the functional element (4, 14, 15) by axial spreading of the Spreizelementes (8) of at least one wall section (8.1) from an original shape in which this wall section (8.1) in sectional planes, the Spreizringachse (SA) or the axis of the shaft (1) enclose, on the inside concave and convex on the outside, is deformed by overpressing into a waisted shape permanently. 16. The method according to claim 15, characterized in that the spreader ring (8) is deformed before the axial spreading for axial support. 17. The method according to claim 16, characterized in that the spreader ring (8) is deformed before the axial spreading so that the first edge region (8.2) abuts against an on the shaft (1) formed axial support surface (12). 18. The method according to claim 16, characterized in that the spreader ring (8) is deformed before the axial spreading so that the first edge region (8.2) in a on the shaft (1) provided for the first groove (12) engages. 19. The method according to any one of the preceding claims, characterized in that the spreader ring (8) is deformed before the axial spreading so that the second edge region (8.3) in a this edge region (8.3) associated second groove (13) of the shaft ( 1) engages. 20. The method according to any one of the preceding claims, characterized in that the spreader ring (8) is placed as an open ring on the shaft (1) and then deformed into a closed ring by radial force. 21. The method according to any one of the preceding claims, characterized in that the deformation of the wall portion (8.1) during axial spreading of the spreader ring (8) takes place such that the deformed or waisted wall portion (8.1) abuts against the shaft (1) and this is immediately adjacent. 22. The method according to any one of the preceding claims, characterized in that the deformation of the wall portion (8.1) during axial spreading of the spreader ring (8) takes place such that the depth (b) of the sidecut of the wall portion (8.1) after spreading is smaller than the dimension (a) of the bulge formed by the original shape of this wall section (8.1). 23. Spreizring for use in a shaft assembly according to any one of claims 1-13 and / or in a method according to any one of claims 15 - 21, characterized by the formation of the Spreizringes (8) as an open annular body having a Spreizringachse (SA) partially enclosing wall portion (8.1) with two of the wall portion in the direction of Spreizringachse (SA) radially inwardly extending and with respect to the Spreizringachse (SA) axially offset edge regions (8.2, 8.3) is provided, wherein the wall portion (8.1) in the Spreizringachse (SA) enclosing cutting planes on the inside concave and convex on the outside. 24. Spreizring according to claim 23, characterized in that the wall portion (8.1) has a plurality of webs (11) and openings (10) or openings therebetween. 25. Spreizring according to any one of the preceding claims, characterized by its production of a permanently deformable, for example metallic flat material.