WO2010028669A1

WO2010028669A1 - Boot with rib elements

Info

Publication number: WO2010028669A1
Application number: PCT/EP2008/007560
Authority: WO
Inventors: Markus Deisinger; Ludger Wenning; Joachim Wette; Andreas Berndt
Original assignee: GKN Driveline International GmbH
Current assignee: GKN Driveline International GmbH
Priority date: 2008-09-12
Filing date: 2008-09-12
Publication date: 2010-03-18
Anticipated expiration: 2011-03-12

Abstract

The present invention provides for a boot with a fold region (16) having a first attachment region (12) which is assigned to a joint with a binder seat region (18), the first attachment region comprising an outer surface (54), and an inner surface directed (56) to the joint, wherein on the inner surface at least two rib elements (30) are arranged on a first side region (58) of the first attachment region opposite the fold region, the at least two rib elements being separated from each other.

Description

Boot with rib elements

The present invention relates to a boot with a fold region having a first attachment region which is assigned to a joint with a binder seat region, the first attachment region comprising an outer surface and an inner surface, the latter being directed to the joint casing.

Boots in accordance with the present invention may be used especially for constant velocity joints, and may be designed as convoluted boots having a plurality of folds in the fold region, as well as roll boots having only one fold in the fold region. Such boots amounted on joint casings by way of a binder element, also called tensioning element, being also used to fix said boots on a shaft in a second attachment region being opposite arranged from the first attachment region in a boot in accordance with the present invention. Such boots are usually made of a thermoplastic elastomere material or mixtures of thermoelastic plastomere materials, for example based on polyurethane (TPU), polyamide (TPA), polyolefines (TPO), polyester (TPEE) or a thermoplastic elastomere vulcanizate (TPV), or a thermoplastic poly-ether-ester-elastomere (TEEE). The material or mixtures of materials of the boots in accordance with the present invention may be made of or may further comprise other materials, especially additives like diffusion-promoting add mixtures or any other additives a person skilled in the art will be aware of in view of the use of the boots in question, especially in view of the demands of automotive industry if the boots are used for automotives. However, the boots in accordance with the present invention may also be made of usual rubber-elastic materials.

Due to the necessity of mounting boots on a joint casing by way of a binder element, a problem exists with respect to the fitting of the boot on the joint casing due to the stress exerted from the binder element and a flowing into spaces underneath the binder element, thereby loosening the connection with each other. In order to solve that problem, US 5,094,894 proposes a boot with at least one collar region, comprising on its outside an annular groove with a rectangular or trapezoidal cross-section for a tensioning element, said annular groove is provided for with a substantially flat bottom part resting against the tensioning element and is wider than an internal annular bead. The collar region, within the flat annular groove in the region of the internal annular bead comprises at least one recess-like annular gap with a rectangular or trapezoidal cross-section whose cross- sectional depth is greater than its width. Further, on the inner surface of the collar region resting against the joint casing two annular beads are assigned to the two recess-like annular gaps shown in the Fig. of US 5,094,894. However, the problem of the embodiment disclosed in US 5,094,894 is that it may not be fixed in a defined axial position in an annular groove of a joint casing. The boot in accordance with US 5,094,894 will show a high flexibility in the axial direction with respect to the fixing of the same by a binder element in an annular groove of a joint casing, whereby the flexibility will cause deformations during tensioning. Further, the pressure forces exerted by the binder element will flow in an uncontrolled way into the material of a boot in the binder seat region giving rise for sealing problems.

It is, thus, an object to the present invention to provide for a boot and a system comprising such a boot as mentioned above showing increased sealing and fixing properties compared to the boots known from the state of the art.

Said object is solved by a boot as defined above, wherein at least two rib elements are arranged on a first side region of the first attachment region opposite the fold region, the at least two rib elements being separated from each other. The boot in accordance with the present invention shows the advantage that due to the provision of at least two rib elements on the inner surface of the first attachment region the boot may be mounted in a defined position because the rib elements may provide for contact points with respect to a first side wall of the annular groove of the joint casing. Good fitting and sealing properties are obtainable with a boot in accordance with the present invention.

In a preferred embodiment of the present invention, a plurality of rib elements are circumferentially arranged on the inner surface. For example, four, five, six, seven or more rib elements may be arranged circumferentially on the inner surface of the first attachment region. Most preferred, at least such a number of rib elements are arranged circumferentially on the inner surface so that throughout the whole circumferentially arranged side wall of the annular groove contact points exist between the rib elements and the first side wall of the annular groove, however, with a space between the rib elements.

In a further preferred embodiment of the present invention, on the outer surface of the first side region of the first attachment region, and assigned to at least one rib element, a material massing is arranged extending from the outer surface. Said material massing may provide for a defined seat for the binder element. Preferably, the material massing defines a boundary surface for such a binder element, being especially provided by the side wall of the material massing being directed to an opening of the joint casing. In a preferred embodiment, a material massing is assigned to each rib element. The binder element in accordance to the present invention may be fixed on a joint casing by way of each kind of fasteners/binder elements known from the prior art, such as clamping elements, especially clamping straps, but also clamp or compression rings. Said fasteners exhibit clamping and/or compression forces on the binder seat region of the boot.

It is further preferred that the material massing comprises a slit. Said slit preferably extends from an opening of the same towards the inner surface of the first attachment region. However, it is also possible that the material massing comprises no slit or any other kind of a recess like a gap.

In a further preferred embodiment of the present invention, at least the bottom of the slit of the material massing shows a curved shape, viewed in a direction perpendicular to a main axis of the boot. However, in no way the design of the slit of the material massing is limited, and any further designs, especially of the bottom, of the slit of the material massing may be used in the context of the present invention, a person skilled in the art will be aware of.

In a further preferred embodiment of the present invention, on the inner surface at least one, preferred at least two, most preferred at least three circumferential rib or ribs is or are arranged. One of the at least one circumferential ribs may provide for contact points, however, on a second side wall of the annular groove opposite to the first side wall and near the fold region. The stiffness of the binder seat region is reduced, especially when at least three circumferential ribs are arranged on the inner surface of the first attachment region.

In a further embodiment of the present invention, on the outer surface of a first attachment region at least three circumferential slits are arranged extending from the outer surface towards the inner surface of the first attachment region. Further preferred, one circumferential slit is assigned to one circumferential rib. In a further preferred embodiment, to each circumferential rib on the inner surface of the first attachment region a circumferential slit is assigned on the outer surface of the first attachment region. A circumferential slit may alternatively be assigned only to one, two, or three, or a plurality of circumferential ribs in the boot in accordance with the present invention. The slits preferably show a rectangular or trapezoidal cross-section. Further, the slits may show a cross-sectional depth that is greater than its width, although the depth and width, viewed in a cross-section, also may essentially be the same in a further preferred embodiment of the present invention.

Further preferred, the rib element arranged in the first side region being opposite the fold region of the first attachment region is neighbouring a rib arranged on the inner surface of a first attachment region. Preferably, the rib element is assigned to a first neighbouring rib of the first attachment region such that a groove is arranged for between the rib element and the neighbouring rib. In a further preferred embodiment of the present invention, the circumferential ribs neighbouring each other in the first attachment region are also separated from each other by means of a groove.

It is further preferred that at least one circumferential rib and/or the at least two rib elements have a curved shape, viewed in a direction to the main axis of the boot. Thus, in a sectional view of the first attachment region one may also address the ribs and rib elements as annular beads or bead elements.

In a further preferred embodiment of the present invention, on the first side region of the first attachment region at least two arrangement means for the binder element are arranged. Further preferred, the rib elements are arranged between assignment means, that is arrangement means and rib elements alternate in the first side region of the first attachment region of the boot in accordance with the present invention, however, being preferably separated from each other by spaces if viewed in a direction perpendicular to the main axis. Preferably, at least two arrangement means and at least two rib elements are arranged in the first side region, the arrangement means and/or the rib elements are arranged in pairs arranged opposite to each other in the first side region, if viewed in a direction perpendicular to the main axis. However, preferably a plurality of arrangement means and rib elements are alternately arranged in the first side region of the first attachment region of the boot in accordance with the present invention, for example six, seven, eight or more arrangement means are provided for being separated from each other by rib elements. The arrangement means give the binder element a defined seat, in addition to the material massing assigned to the rib element. However, said arrangement means are not essential means in the context of the present invention, especially for solving the object of the present invention, however, may be arranged for advantageously with respect to special binder elements that may be used for mounting the boot in accordance with the present invention on a joint. The invention also refers to a system comprising a boot as described before and in the following and a joint casing, and, further, preferably also comprises at least one binder element.

Other advantages and features of the invention will become apparent to one of skill in the art upon reading the following detailed description with reference to the drawings illustrating features of the invention by way of example.

Brief description of the drawings

For a more complete understanding of this invention, reference should now be made to the embodiments illustrated in greater detail and the accompanying drawings as described below by way of examples of the invention.

In the drawings:

Fig. 1 is a side view of an embodiment in accordance with the present invention in the form of a boot.

Fig. 2 is a first partial sectional view through the first attachment region of the embodiment of the present invention in accordance with Fig. 1 in a direction of a main axis.

Fig. 3 is the second partial sectional view through the first attachment region of the embodiment of the present invention in accordance with Fig. 1 in a direction of a main axis.

Fig. 4 is a partial sectional view along section A-A of Fig. 3, thus being perpendicular to a main axis of the boot.

Fig. 5 is a perspective view of the embodiment of the present invention in accordance with Fig. 1.

Fig. 6 is a partial perspective view of the embodiment of the present invention in accordance with Fig. 1.

Fig. 7 is a partial sectional view of a second embodiment of the present invention showing a system with a first attachment region of a boot mounted on a joint casing. Detailed description and description of the drawings

While the present invention is described with respect to a boot, the present invention may be adapted and utilized for other fixable sealing applications mating with a circumferential surface of a stretchable part, including such applications outside of the constant velocity joint art.

In the following detailed description, special orienting terms are used such as "outside", "inside", "opposite" and the like. It is to be understood that these terms are used for convenience of description of the components or embodiments by reference to the drawings. These terms do not necessarily describe the absolute location and space, such as upward, downward, left, right etc., that any part must assume. Further, in the following description, various operating parameters and components are described for several constructed embodiments. These specific parameters and components are included as examples and are not meant to be limiting.

In the context of the present invention, the phrase "assigned to" means that circumferential slits and/or ribs and/or rib elements and/or material massings, respectively, are arranged on the outside or the inside, respectively, of the first attachment region in similar regions in a cross-sectional view in the direction of the main axis of the boot. Especially, the slits and material massings must not be arranged within the width of the rib element or the ribs, but may also only partially be arranged in a region corresponding to the width as defined by a rib or a rib element. However, it is preferred that the material massing and circumferential slits are arranged essentially centered within the width of a circumferential rib or a rib element, respectively.

As already mentioned at the beginning, the boots can be manufactured of a thermoplastic elastomer material or any other kind of elastomer material, especially a rubber elastomer material, or mixtures thereof. Advantages are provided by thermoplastic elastomer materials. These includes materials known from the prior art that has two different polymer segments, namely a relatively rigid resin segment and an elastic soft segment. The individual polymer segments are comprised of longer chains of similar monomers. The resin segments hold the soft segments together by physical, network-like bonds. A thermoplastic elastomer material for manufacturing boots in accordance with the present invention is the thermoplastic material marked under the brand name "Hytrel" by the DuPont company. In another aspect of the invention, the first and/or a second attachment region of the boot is at least partially manufactured of an elastomer material. In contrast to thermoplastic elastomer materials, an elastomer material has the advantage of having a reduced so- called "cold flow" then situated underneath the fastening element. This cold flow is understood to be the phenomenon in which, when subjected to clamping or compression stress, the plastic material in the first, but also in the second attachment region "escapes" literally from the fastener, as a result of which the boot can come loose during operation, particularly when under thermal stress. Other regions of the first and/or second attachment region can nevertheless be manufactured of a thermoplastic elastomer material. The same advantage can also be achieved if a layer of the thermoplastic elastomer material is placed underneath the elastomer material. Possible elastomer materials include for example polyurethane rubber, polyester-based polyurethane/rubber mixtures or polycloroprenes.

The boot according to the present invention can be produced by way of a pressblower injection blow moulding process, however, may also be produced with an injection/intrusion process, an injection moulding process, an injection/pressing process and/or an extrusion/blow moulding process. The pressblower injection blow moulding process and the injection/extrusion process are advantageously used, because precisely- dimensioned boots may be produced by said processes.

Referring now to the drawings where like reference numerals are used to identify identical components in the various views, Fig. 1 illustrates a side view of a boot 10 in a first embodiment of the present invention. The boot 10 shows a first attachment region 12 that is to be assigned joint casing, as well as a second attachment region 14, that may be assigned to a shaft. Especially, the boot 10 in accordance with Fig. 1 may be used for constant velocity joints. Between the first attachment region 12 and the second attachment region 14, a fold region 16 comprising seven folds 20.1 to 20.7 is located. The first attachment region 12 comprises an outer surface 54 and a binder seat region 18 in which a binder element not shown may be seated. Further, a first side region 58 of the first attachment region 12 comprises a plurality of arrangement means 22 and a plurality of slits 36 being alternately arranged in the first side region 58. The first side region 58 is located opposite the fold region 16 at the first attachment region 12. A second side region 60 is located opposite the first region 58 at the first attachment region 12, and comprises a plurality of second arrangement means 24 being assigned opposite to the first arrangement means 22. Fig. 2 shows a cross-sectional view through the first attachment region 12 of the embodiment in accordance with Fig. 1 through one slit 36. Four circumferential ribs 28.1 to 28.4 are arranged on the inner surface 56 of the first attachment region 12, that are especially assigned to the binder seat region 18. On the outer surface 54 of the first attachment region 12, four circumferential slits 32.1 to 32.4 are arranged for and assigned to the ribs 28.1 to 28.4 so that the circumferential slits are centered related to the width of the ribs in the cross-sectional view of Fig. 2. The circumferential ribs 28.1 to 28.4 are spaced by circumferential grooves 34.1 to 34.3 from each other and are neighboured directly. The circumferential slits 32.1 to 32.4 show a higher depth than width in a cross- sectional view. The surface of the binder seat region 58 is essentially plane providing for a reception for a binder element.

As one may further derive from Fig. 2, that on an inner surface 56 and in the first side region 58 of the first attachment region 12, a rib element 30 is arranged, to which one slit

36 is assigned on the outer surface 54 of the first attachment region 12. The rib element

30 shows the same cross-sectional shape as the ribs 28.1 to 28.4, however, is not defined as being an annular rib. Instead, the rib element 30 is isolated and spaced from at least one further rib element 30 by way of a groove 38. A material massing 26 is assigned to the rib element 30, and comprises the slit 36 being centrally arranged with respect to a cross-section of the rib element 30. The material massing 26 further provides for a wall 40 providing for a boundary surface for a binder element not shown, and, thus, provides for a boundary of the outer surface 54. The width of the rib elements 30 on the inner surface 56 of the first attachment region 12 may be smaller, essentially the same or greater than the assigned material massing 26.

Fig, 3 is a cross-sectional view of the first attachment region through one first arranging means 22. One may derive that no rib element 30 is present on the inner surface 56 of the first attachment region 12 in the first side region 58 to the first arrangement means 22. Further, the first arrangement means 22 shows a slit 45 having an opening in a direction to the inner surface 56 of the first attachment region 12.

Fig. 4 is a sectional view across line A-A of Fig. 3, and shows the shape of slits 36 as well as of the slits 42 of the first arrangement means 22. Especially, one may derive that the bottom 37 of a slit 36 has a curved shape. Further, also the bottom of a slit 42 of the first arrangement means 22 has a curved shape. The radius of the curved shape of the top of

RECTIFIED SHEET (RULE 91) ISA/EP slit 42 and the bottom 37 of slit 36 may be essentially the same or may deviate from each other.

Fig. 5 shows a perspective view of the first embodiment of the present invention in accordance with Fig. 1 from which one may derive the alternating arrangement of the rib elements 30 with the first attachment means 22, whereby the rib elements 30 are arranged on the inner surface 56 of the first attachment region 12, whereas the first arrangement means 22 are arranged on the outer surface 54 of the first attachment region 12. Further, one may derive that opposite the first attachment means 22, second attachment means 24 being located near the fold region 16 in the first attachment region 12. In accordance with the invention, however, it is not necessary to provide for first and/or second attachment means 22, 24. The rib element 30 bears a side surface 68 that may be in contact with a side wall of a groove of a joint casing (see Fig. 7), especially in a clamped state.

Fig. 6 shows a partial perspective view of the first embodiment of the present invention. One may see that the slits 36 comprises two edges 44.1 and 44.2 defining an opening 64. A person skilled in the art, however, may foresee any other embodiment of the material massings 26, especially a material massing 26 without any slit 36. Further, the material massing 26 may also show any other geometry and/or dimensions easily derivable for a person skilled in the art.

Turning now to Fig. 7, Fig. 7 shows a second embodiment of the present invention, namely a system comprising a boot 10, a joint casing 46 and a binder element 62. Fig. 7 is a sectional view through a first attachment region 12 of a boot 10 being mounted on the joint outer casing 46 by way of the binder element 62 that may be a usual clamp strap. One may derive that a rib 28.4 neighbouring a second side region 60 of the first attachment region 12 provides for a contact point of an annular groove 48 of the joint casing 46 and a second side wall 49, whereas a rib element 30 is located near or at a first side wall 47 of said annular groove 48, that may provide for a contact point with the first side wall 47 of said annular groove 48, especially in a clamped state. Thus, the boot 10 may be positioned in the annular groove 48, having a ground 66 between the first and the second side wall 47 and 49, with its first attachment region 12 in a defined way, whereas when crimping the clamp strap 62 the exerted forces may uniformly flow in the material of the first attachment region 12. The present invention consequently creates a boot which through the provision of rib elements on the inner surface of a first attachment region of the boot permit a more precise installation, particularly in the case of linkage components, especially in an annular groove of joint casings. A secure and evenly sealed mounting of the boot on a casing by way of a binder element is assured through the provision of the rib elements.

While the inventor's boot has been described in connection with one or more embodiments, the disclosure is not meant to be limiting. Rather, the invention covers all alternatives, modifications and equivalents within the spiritual scope of the appended claims taking into account the description above.

Claims

Patent claims

1. Boot (10) with a fold region (16) having a first attachment region (12) which is assigned to a joint with a binder seat region (18), the attachment region (12) comprising an outer surface (54), and an inner surface (56) directed to the joint, characterized in that on the inner surface (56) at least two rib elements (30) are arranged on a first side region (58) of the attachment region (12) opposite the fold region (16), the at least two rib elements (30) being separated from each other.

2. A boot according to claim 1 , characterized in that the plurality of rib elements (30) are circumferentially arranged on the inner surface (56).

3. A boot according to anyone of the preceding claims, characterized in that on the outer surface (54) and in the first side region (58) of the first attachment region (12) and assigned to at least one rib element (30) a material massing (26) is arranged extending from the outer surface (54).

4. A boot according to claim 3, characterized in that the material massing (26) defines a boundary surface (40) for a binder element (62).

5. A boot according to claim 3 or 4, characterized in that the material massing (26) comprises at least one slit (36).

6. A boot according to claim 5, characterized in that at least a bottom (37) of the slit (36) shows a curved shape, viewed in a direction perpendicular to a main axis (66) of the boot (10).

7. A boot according to anyone of the preceding claims, characterized in that on the inner surface (56) at least one circumferential rib (28) is arranged.

8. A boot according to anyone of the preceding claims, characterized in that from the outer surface (54) of the first attachment region (12) at least three circumferencial slits (32) are arranged extending from the outer surface (54) towards the inner surface (56).

9. A boot according to claim 8, characterized in that the circumferential slits (32) are assigned to circumferential ribs (28).

10. A boot according to anyone of the preceding claims, characterized in that in the first side region (58) at least two first arrangement means (22) for the binder element (62) are arranged.

1 1. A boot according to claim 10, characterized in that the rib elements (30) are arranged between first arrangement means (22).

12. A boot according to anyone of the preceding claims, characterized in that the at least one rib (28) and/or the at least two rib elements (30) have a curved shape, viewed in a direction of the main axis (66) of the boot (10).

13. System comprising a boot (10) according to anyone of claims 1 to 12 and a joint casing (46) with an annular groove (48) on the outer surface in which the rib elements (30) and the at least one circumferential rib (28) engage.

14. System according to claim 13, characterized in that if further comprises at least one binder element (62).