EP1526991A1

EP1526991A1 - Window wiping device and wiper arm, especially for a motor vehicle

Info

Publication number: EP1526991A1
Application number: EP03717112A
Authority: EP
Inventors: Michael Weiler; Joachim Zimmer
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2002-07-30
Filing date: 2003-02-26
Publication date: 2005-05-04
Also published as: BR0305686A; CN1649762A; US20050241098A1; DE10234613A1; JP2005534573A; KR20050032024A; WO2004016482A1

Abstract

The invention relates to a window wiping device (10), especially for a motor vehicle. Said device comprises a wiper shaft (28, 30) which is provided with a cone (34) and to which a wiper arm (32) can be fixed, said cone (34) being superimposed by a macroscopic structure. The invention also relates to a wiper arm (32), especially for a window wiping device (10), said wiper arm comprising a fixing element (47) provided with an inner cone (37) which can be fixed to a cone (34) and is superimposed by a macroscopic structure.

Description

Windshield wiper device and wiper arm, in particular for a motor vehicle

State of the art

The invention relates to a windshield wiper device and a wiper arm, in particular for a motor vehicle according to the type of the independent claims. Numerous windshield wiper devices are already known which have a wiper shaft which is provided with a cone to which a wiper arm can be attached. In the area of their attachment to the cone, the wiper arms are provided with a matching inner cone, which is pressed onto the cone of the wiper shaft of the windshield wiper device. For this purpose, a thread connects to the cone, onto which a nut is screwed, which presses the wiper arm onto the cone.

The wiper arms in this fastening area are usually made of a cast material, for example of die-cast aluminum or zinc. The cone is provided with a knurling which digs into the fastening part when the wiper arm is pressed on and increases the torque which can be transmitted from the wiper shaft to the wiper arm due to the positive engagement.

However, the fastening parts are increasingly being manufactured as stamped and bent parts from sheet steel, which has a significantly higher surface hardness than that of the

Fastening parts made of die-cast aluminum or zinc is the case. In order for the knurling of the cone to dig into the fastening part, significantly higher tightening torques have to be achieved with the locking nut, which in extreme cases can lead to the thread of the wiper shaft breaking off during assembly. Advantages of the invention

The windshield wiper device according to the invention with the features of the main claim has the advantage that the force with which the cone of the wiper shaft is pressed into the wiper arm is increased by a macroscopic structure which is superimposed on the cone, with the same contact pressure of the wiper arm on the wiper shaft. Knurls arranged on the cone can thus dig better and deeper into the surface of the wiper arm, as a result of which the connection between the wiper shaft and the wiper arm is strengthened and higher torques can also be transmitted when using fastening parts with higher surface hardness.

The measures listed in the subclaims result in advantageous developments and improvements of the features specified in the main claim.

If the average contact area between the cone and the wiper arm is smaller than the effective lateral surface of the cone, the connection is particularly stable.

The easiest way to achieve this is for the cone to have a recess.

If the recess is arranged circumferentially, it can easily be inserted into the wiper shaft when the cone is turned, without the need for further work steps. In addition, the total length of the cone is the same as without a recess. This prevents a reduction in the stability of the wiper arm on the wiper shaft.

In a variation, the puncture can also be arranged in the axial direction, which further reduces the tendency to tilt and improves the alignment of the wiper arm. In addition, it is easier in this way to place the wiper arm on the cone, since it prevents the inner cone from being tilted.

The wiper arm according to the invention with the features of claim 6 has the advantage that a higher torque can be transmitted from the wiper shaft to the wiper arm by a macroscopic structure that is superimposed on the inner cone of the fastening part, without the contact pressure of the wiper arm on the cone being increased got to. ^This' can be realized in a simple manner in that the average contact area between the inner cone and the cone of the wiper shaft is provided as the effective circumferential surface of the inner cone smaller.

The easiest way to achieve this is if the inner cone has an undercut.

Such an undercut is particularly easy to manufacture if it is arranged circumferentially.

If the undercut is arranged in the axial direction, the placement of the wiper arm on the wiper shaft is facilitated since it cannot be misjudged. In addition, the susceptibility to tipping is further reduced. This is especially true when the number of axial undercuts is odd.

drawings

Embodiments of the invention are shown in the drawings and explained in more detail in the following description. Show it:

Figure 1, an inventive wiper device in perspective

Presentation,

Figure la, a cone of a wiper shaft with wiper arm according to the prior art in a schematic representation, Figure 2, the cone of a wiper shaft according to the invention

Windshield wiper device in a side view,

FIG. 3, the cone from FIG. 2 in a variation,

Figure 4a to 4c, different designs of the macroscopic structure of the cone

FIG. 3, FIG. 5, a further variation of the cone from FIG. 2,

6a to 6b, different designs of the macroscopic structure of the cone from FIG. 5 in cross section,

7, a further variation of the cone from FIG. 2, FIG. 8, a cross section through a cone from FIG. 7, FIG. 9, a wiper arm according to the invention in a perspective view, FIG. 10 shows a section through the fastening part of a wiper arm according to the invention with an undercut with a widened inner cone,

FIG. 10a shows a section through the fastening part of a wiper arm according to the invention with an undercut when the inner cone is compressed, FIG. 11 shows a section through a variation of a wiper arm according to the invention

Figure 10a,

12a to 12c, various designs of the wiper arm according to FIG. 11 with several circumferential undercuts,

Figure 13, a section through an inventive wiper arm with axial undercuts and

FIG. 14 shows a section through the wiper arm from FIG. 13.

Description of the embodiments

Figure 1 shows a windshield wiper device 10 according to the invention in perspective

Presentation. This comprises a carrier tube 12 which has two ends, to each of which a wiper bearing 14, 16 is attached. In the middle of the longitudinal extent of the carrier tube 12, a wiper motor 16 is arranged as a drive unit, which sets a crank 18 either in a to-and-fro or in a circumferential movement. The free end of crank 18 is connected to two push rods 20, 22 which move drive cranks 24, 26 which drive wiper shafts 28, 30. The wiper shafts 28, 30 are rotatably mounted in the wiper bearings 14, 16 and, when assembled, receive wiper arms 32 (FIG. 9), on the free ends of which wiper blades can be attached. For fastening the wiper arm 32, the wiper shaft 28 has a cone 34, which is closed by a cylindrical thread 36.

The connection of the wiper shaft 28 to the wiper arm 32 according to the prior art is shown in detail in cross-section in FIG. The cone 34 has a knurling 35 which digs into an inner cone 37 of the wiper arm 32. The knurling 35 consists of small parallel notches which are spaced apart by less than 0.5-1 mm, preferably less than 0.5 mm, in particular less than 0.3. The inner cone 37 of the wiper arm 32 touches the cone 34 in the region of its effective lateral surface, which here extends from the lower edge 39 of the inner cone 37 to the upper edge 41 of the inner cone 37 around the cone 34. The average contact area between cone 34 and wiper arm 32 is effective

Given the lateral surface of the cone 34, which caused by the knurling 35 Surface enlargement is ignored. The inner cone 37 of the wiper arm 32 is pressed onto the cone 34 by a nut 43 which is screwed onto the thread 36.

Figure 2 shows the end of the wiper shaft 28 of an inventive

Windshield wiper device 10 to which the wiper arm 32 is attached. The wiper shaft 28 essentially has three sections, a cylindrical first section 38, the cone 34 as the second section and the thread 36 as the third section. The cone 34 is provided with a circumferential recess 40 as a macroscopic structure, the width B of which corresponds approximately to half the height H of the cone 34.

As a result, the effective lateral surface of the cone 34 - that is to say the region of the lateral surface of the cone 34 that is inside the inner cone 37 in the assembled state - is larger than the central contact surface of the cone 34, that is to say larger than the contact surface that actually occurs when the inner cone 37 is put on comes into contact with the cone 34, the surface change due to the knurling .35 being ignored. The macroscopic structure here has a large one, which extends over several notches of the knurling 35.

By reducing the central contact surface of the cone 34, the force with which the cone 34 presses against the inner cone 37 remains the same

Tightening torque of the nut 43, larger. Knurling 35 can thereby dig better into inner cone 37, as a result of which the torque transmission from wiper shaft 28 to wiper arm 32 is increased.

The recess 40 is arranged approximately in the middle of the longitudinal extent of the cone 34, so that the outer regions of the effective lateral surfaces in the axial direction come into contact with the inner cone 37 of the wiper arm 32. The entire height H of the cone 34 thus has a stabilizing effect, thereby preventing the wiper arm 32 from tilting.

FIG. 3 shows a variation of the wiper shaft 28 from FIG. 2. The cone 34 of the wiper shaft 28 here has a plurality of step-like recesses 40 as a macroscopic structure. These recesses 40 create teeth 42 which can dig into the inner cone 37 when the latter is fitted. Every second groove 40 is also alternately provided with a knurling 35. The punctures 40 from FIG. 3 are shown in detail in FIGS. 4a to 4c. In FIG. 4a, the recesses 40 are straight, that is to say only made axially, that is to say that the steps are designed as concentric cylinders with the wiper shaft 28. In Figure 4b, the steps are tapered so that the teeth 42 have a steeper tooth angle. The same applies to FIG. 4c, but in which the teeth are in opposite directions

Are inclined towards.

The undercuts from Figure 4b and Figure 4c must be machined because of their undercut. In contrast to this, the recesses 40 from FIG. 4a can, however, be removed from the mold and do not require any additional machining. In this way, the steps 40 of the cone 34 can also be provided directly when the cone 34 is compressed.

FIG. 5 shows a further variation of the cone 34 from FIG. 2. However, the recesses 40 as a macroscopic structure are arranged here in the axial direction and extend essentially over the entire height H of the cone 34 which comes into contact with the inner cone 37.

FIG. 6 shows a cross section through a cone according to FIG. 5. Five radius-like recesses 40 are provided which are designed such that they touch and teeth 42 form on the contact lines, which are able to dig into the inner cone 37. Of course, the punctures 40 can also be arranged separately from one another, that is to say not or only partially touching one another.

FIG. 6b shows a variation of the cross section from FIG. 6a. Here are the

Punctures 40 are flat so that a pentagon results.

Of course, 3, 9 or more punctures 40 can also be provided, but the number of punctures 40 should be odd in order to improve the stability of the connection overturning.

FIG. 7 shows a further variation of the cone 34 from FIG. 2. The cone 34 is here provided with the knurling 35 which is pierced by elliptical incisions as recesses 40. By means of such elliptical recesses 40, the middle contact surface between inner cone 37 and cone 34 can be reduced in such a way that the

Knurling 35 improves digging into the inner cone 37. FIG. 8 shows a cross section through the cone from FIG. 7. The elliptical recesses 40 break through the knurling 35 and thus reduce the contact area between the inner cone 37 and cone 34.

FIG. 9 shows a wiper arm according to the invention in a schematic side view. This comprises at least one joint part 45, which is fastened in a rotatable manner to a fastening part 47. The fastening part 47 is produced in a stamping and bending process and the inner cone 37 at its end facing away from the memorial part 45. This serves to fasten the wiper arm 32 to the

Wiper shaft 28.

FIG. 10 shows a cross section through a fastening part from FIG. 9 in the area of the inner cone 37. The inner cone 37 has an undercut 49, so that the middle contact surface between the cone 34 of the wiper shaft 28 and the inner cone 37 of the

Fastening part 47 reduced. The circumferential undercut 49 is arranged in the axial direction approximately m of the center of the inner cone 37 and is designed such that the mean contact area of the cone 34 is reduced in relation to the effective lateral surface of the cone 34 or the inner cone 37.

Here the inner cone 37 is produced by an expanded bend in the steel sheet. In the following figures, however, the inner cone 37 is formed so that the wall thickness on the side of the inner cone 37, which has the larger diameter, is somewhat thinner than on the side, which has the smaller diameter (FIG. 10a). However, these two variants are interchangeable.

FIG. 11 shows a variation of the fastening part 47 from FIG. 10. The inner cone 37 here has a plurality of undercuts 49, as a result of which teeth 42 are formed here, which are able to dig into the cone 34 or the knurling 35 of the cone 34. The undercuts 49 again reduce in the middle contact area of the cone 34 in relation to the effective lateral surface of the cone 34 or the inner cone 37.

The undercuts 49 are shown in detail in FIG. In FIG. 12a, the undercuts are made straight, which can be produced by simple upsetting in production. Figures 12b and c show the undercuts 49 in a variation of Figure 12a provided an undercut, whereby the tooth angle becomes steeper and the teeth 42 can dig into the cone 34 of the wiper shaft 28 better. Figure 12c shows the same as in Figure 12b, but here the undercuts and thus the teeth 42 are formed in the opposite direction. Although this is more complex to produce than straight undercuts 49, as in FIG. 12a, since machining is required, the connection between wiper shaft 28 and fastening part 47 is further improved.

FIG. 13 shows a further variation of the fastening part 47 from FIG. 10. Here, however, the undercuts 49 are not arranged all around, but in the axial direction.

FIG. 14 shows a cross section through the inner cone 37 of the wiper arm 32 from FIG. 13. The undercuts 49 reduce the contact area between the wiper shaft 28 and the inner cone 37, so that the knurling 35 of the cone can dig more deeply into the inner cone 37 of the fastening part 32.

Claims

Expectations

1. Windshield wiper device (10), in particular for a motor vehicle, at least comprising a wiper shaft (28, 30) with a cone (34) to which a wiper arm (32) can be fastened, and has a knurling (35), characterized in that a macroscopic structure is superimposed on the cone (34).

2. Windscreen wiper device (10) according to claim 1, characterized in that the average contact area between the cone (34) and wiper arm (32) is smaller than the effective lateral surface of the cone (34).

3. windshield wiper device (10) according to claim 1 or 2, characterized in that the cone (34) has at least one recess (40).

4. Windshield wiper device (10) according to claim 3, characterized in that at least one puncture (40) is arranged circumferentially.

5. Windshield wiper device (10) according to claim 3 or 4, characterized in that at least one puncture (40) is arranged in the axial direction.

6. wiper arm (32), in particular for a windshield wiper device (10) according to one of the preceding claims, comprising a fastening part (47) with an inner cone (37) which can be fastened to a cone (34), characterized in that the inner cone ( 37) a macroscopic structure is superimposed.

7. wiper arm (32) according to claim 6, characterized in that the average contact area between the inner cone (37) and cone (34) is smaller than the effective lateral surface of the inner cone (37).

8. wiper arm (32) according to one of claims 6 or 7, characterized in that the inner cone (34) has at least one undercut (49).

9. wiper arm (32) according to claim 8, characterized in that at least one undercut (49) is arranged circumferentially.

10. wiper arm (32) according to claim 8 or 9, characterized in that at least one undercut (49) is arranged in the axial direction.