Patent Application
20150260228
This patent claims priority from German Patent Application No. 10 2014 204571.1 filed on Mar. 12, 2014, which application is incorporated herein by reference its entirety.
The invention relates to a bushing and to a transmission arrangement with this bushing.
Bushings are frequently used in transmission technology in order to selectively reinforce areas or to create functional areas. Such bushings are impressed in many applications in order for them to be fixed in the surrounding construction so that they cannot get lost.
A multifunctional bushing is disclosed, for example, in the publication DE 10 2009 052759 A1. In this publication an interference fit assembly is described with a bushing-like part, which is fixed at a carrier in a force-fitting fashion, with at least one recess being embodied at the surface of the carrier, which is covered by at least one wall section of the bushing-like part, with the thickness of the sheet metal of the wall section at least partially covering the recess being thicker than the sheet metal of the bushing-like part directly abutting the wall section in at least one direction and forming with the bushing-like part the form-fitting connection to the carrier in the surroundings of the recess. The part comprises a plurality of radially extending holes, which end in the recess of the carrier, with the recess together with the penetrating opening forming a channel. In some embodiments a shaft may be accepted in the bushing.
The invention is based on the objective to expand the optional applications for such bushings. Preferred or advantageous embodiments of the invention are discernible from the claims, the following description, as well as the attached figures.
Within the scope of the invention a bushing is disclosed, which is embodied to form a force-fitting connection to a force-fitting partner. Here, the force-fitting connection preferably represents an interference fit assembly. A bushing is particularly embodied such that it can be pressed upon its force-fitting partner or pressed into the force-fitting partner. In particular, the bushing and the force-fitting partner form an interference fit assembly.
The bushing comprises a particularly straight, hollow-cylindrical basic body. Sections may abut the hollow-cylindrical body, particularly at the ends, such as flange sections or locking sections. The basic body defines with its axis of symmetry and/or rotary axis a primary axis, which is referenced in the following.
The basic body comprises at least one coupling section, with the coupling section forming a part of the wall of the basic body. At least one penetrating opening is inserted inside the coupling section, extending radially in reference to the primary axis. In other words, the basic body comprises at least one aperture in the coupling section. The penetrating opening serves for the fluidic communication with a fluid area in the force-fitting partner, particularly a lubricant area and/or refrigerant area. The bearing partner may also show fluid areas, with the fluid areas of the bearing partner being connected via the penetrating openings to the fluid areas of the force-fitting partner. The basic body may also show several such coupling sections, with each of them preferably showing at least one penetrating opening. It may also be provided that one or more additional coupling sections are provided, which are not equipped with a penetrating opening.
The basic body is designed such that a wall thickness in the coupling section is larger than a wall thickness in a neighboring section of the basic body abutting said coupling section. Thus, the coupling section represents an area with a greater wall thickness and a neighboring section abutting thereto represents a section with a lower wall thickness. The coupling section and/or the neighboring section each form a section, particularly a surface section, in the basic body. It may be provided that the neighboring section surrounds the coupling section entirely and/or circumferentially. Alternatively it may be provided that two or more abutting neighboring sections are arranged at a coupling section. It may also be that the coupling section extends to an edge area of the basic body and is limited by one, two, or more neighboring sections.
As explained in the following, the coupling sections are arranged in parts of the basic body which are allocated to fluid areas and/or other recesses of the force-fitting partner. The background of this embodiment is that parts of the basic body, which in the radial direction are overlapping in reference to the primary axis, particularly arranged congruent in reference to the recesses and/or fluid areas of the force-fitting partners, would lead to out-of-roundness and/or local deformation of the hollow-cylindrical basic body, because in the area of the recesses it might yield in the direction of the recesses. In order to compensate this yielding, the coupling sections are provided with a greater wall thickness than the neighboring sections, with the neighboring sections being supported by the force-fitting connection, particularly by interference fit assemblies, on the force-fitting partner. Here, the wall thickness can be sized, based on the result, such that during the production of the force-fitting connection between the bushing and the force-fitting partner the hollow-cylindrical basic body assumes, at its free surface and/or at the surface facing away from the force-fitting partner, a straight cylindrical jacket form or approaches it to the extent possible.
The bushing is embodied for the radial guidance of the bearing partner. The bearing partner may therefore be arranged in the general embodiment of the invention inside the bushing. For example, a bearing partner may be embodied as an axis or a shaft. Or the bearing partner is arranged around a bushing, with the bearing partner being embodied as a stationary or also rotary surrounding construction or as a shaft accept, as a hollow shaft, or as a hollow axle.
It is suggested that the basic body and thus the bushing shows a track section extending about the primary axis, which is embodied for one bearing, particularly a friction bearing or a roller body bearing. In particular, the track section is realized as an annular cylinder jacket on the basic body.
By the embodiment according to the invention another function is integrated in the bushing, which provides that the bushing forms a radial support and/or bearing to guide the bearing partner. The radial bearing can particularly be embodied to guide a rotary motion and/or a pivotal motion. Alternatively, the track section forms only a radial support of the bearing partner here.
In a preferred further development of the invention the wall thickness of the track section is embodied equivalent to the wall thickness of the neighboring section. In particular, it may be provided that the track section forms part of or represents an axial extension of the neighboring section. For example, the coupling section can also form an annular cylinder jacket in the basic body, embodied like a hollow cylinder, with the track section being arranged axially offset in reference to the coupling section.
In a preferred further development of the invention the basic body comprises at least one, preferably several sealing sections, extending in the circumferential direction, particularly extending continuously over the circumferential direction. It is particularly preferred that the sealing sections are realized as additional annular cylinder jackets of the basic body. In preferred embodiments it is provided that the sealing sections overlap the coupling sections. The sealing effect is, however, ensured by the embodiment of the coupling sections showing a greater wall thickness in order to compensate any deformations by the recesses in the force-fitting partner.
However, it is particularly preferred that the track section is arranged outside the coupling sections, because the track section requires a particularly high level of roundness. In particular, the track section is arranged here such that it can be supported on the force-fitting partner in a form-fitting fashion over its entire surface. While in the area of the sealing sections only low radial forces are transmitted, it must be expected in the track section that the radial stress is higher, with a strong support for the bearing being ensured by the embodiment of the track sections outside the coupling section or sections.
In a particular realization of the invention the track section is arranged at a free end of the basic body. In this embodiment particularly the coupling section or sections are positioned between the track section and the other end of the basic body. This way, the track section is arranged outside an area of the bushing, which due to the different wall thicknesses of the coupling section and the neighboring section requires complex processing. In fact, the track section is arranged at the end of the basic body, which shows tapering only a uniform wall thickness so that this way the production is facilitated.
In a preferred realization of the invention a bushing is embodied as a formed part, particularly a metallic formed part. In this realization the bushing can be produced cost-effectively with constant low tolerance ranges. Additionally, a very low wall thickness can be achieved for the coupling sections, the neighboring sections, the track sections, and/or the sealing sections.
It is particularly preferred that the formed part is embodied as a drawn bushing, with the bushing showing a flange end and a tension end. The flange end may be fixed during production with a press pad. The tension end is formed by deformation via material flow, starting with a sheet as a semi-finished part. It is provided that the track section is arranged at the tension end of the drawn bushing. This preferred embodiment has the background that folds may develop at the flange end, particularly when no press pad is used or a press pad of insufficient strength. Although there is the risk at the tension end that so-called bottom cracks develop, this can be controlled easier, so that the tension end represents a high degree of roundness of the drawn bushing and thus represents the better end for the track section.
Another object of the invention represents a transmission arrangement, which is particularly suited and/or embodied for a vehicle. In particular, the transmission arrangement serves for transmitting a driving torque and/or represents a component of a drive train. The transmission arrangement comprises at least one bushing, as described above. The bushing may show all of the above-described embodiments and situations of installation. Further, the transmission arrangement comprises the force-fitting partner, the bearing partner, with the bushing being connected via interference fit and thus via a force-fitting connection to the force-fitting partner. Further, the transmission arrangement shows a roller bearing device, with the roller bearing device being arranged between the bearing partner and the bushing such that they are rotational or pivotal about a rotary axis in reference to each other or mutually support each other. In particular, the roller bodies of the roller bearing device, particularly rolls, roll or support themselves on the track section of the bushing. Particularly preferred, the roller bearing device is embodied as a single-row roller bearing device.
Further, the force-fitting partner shows at least one fluid area, which is coupled in a fluidic fashion to at least one radially extending penetrating opening of the coupling section. In particular, the bushing is embodied as a sealing bushing. The fluid area may be embodied as a recess, particularly as a bore, which is congruent to the radially extending penetrating opening. However, it is more preferred that the fluid area is embodied as an extended recess in the force-fitting partner, which in its area is embodied larger than the allocated penetrating opening such that the remaining fluid area together with the bushing forms a fluid channel between the force-fitting partner and the bushing. In this embodiment the advantages of the invention show particularly strong effects, because the bushing is embodied on the one hand as a sealing bushing for generating at least one fluid channel and is embodied on the other hand as a carrier of the track section for the roller bearing device. This multi-functional part can be connected via the force-fitting connection to the force-fitting partner and this way it can be installed via a single production step.
It is particularly preferred that the bearing partner provides a counter track for the roller bearing device, with the counter track being formed by a base material of the bearing partner. In particular, the area between the roller bearing device and the bearing partner is embodied without bushings and/or the roller bodies of the roller bearing device roll directly on the bearing partner. By waiving another bushing, on the one hand the assembly expense can be reduced, and on the other hand the weight of the transmission arrangement as well. In order to guide the roller bearing arrangement, the counter track may be arranged in a groove.
In one possible embodiment of the invention the bearing partner is embodied as a shaft and the form-fitting partner as a rotational or pivotal hollow shaft or as a surrounding construction, particularly as a shaft accept. This way, the bearing partner can pivot or rotate in the bushing. Optionally, the force-fitting partner and the shaft can be rotated in reference to each other as well. In a particularly preferred embodiment of the invention the transmission arrangement is embodied as an automatic transmission, with the shaft being realized as a drive shaft and the shaft accept as a guide wheel section.
Additional features, advantages, and effects of the invention are discernible from a preferred exemplary embodiment of the invention as well as the attached drawings, wherein:
The guide wheel section 2 is arranged stationary in the transmission arrangement 1. The drive shaft 3 is arranged rotating about a primary axis H in reference to the guide wheel section 2. A bushing 4 is impressed in the guide wheel section 2, with the bushing 4 and the guide wheel section 2 being connected to each other in a force-fitting connection, namely via an interference fit assembly or a force-fit, and with the guide wheel section 2 forming a force-fitting partner for the bushing 4. However, the drive shaft 3 is embodied rotating in reference to the guide wheel section 2 and the bushing 4 such that the drive shaft 3 forms a rotary partner for the bushing 4.
Lubricant channels 5a, b are arranged in the drive shaft 3, which extend in the axial direction towards the primary axis H and which are opened in the radial direction towards the guide wheel section 2. Channel sections 6a, b, c, d, e are arranged on the drive shaft 3, which may be embodied circumferential about the primary axis H or which are embodied only sectionally in the circumferential direction. The lubricant channel 5a ends in the channel section 6b, the lubricant channel 5b ends in the channel section 6d and in the channel section 6e. The channel sections 6a, b, c, d, e and at least one additional section are limited in the axial direction by slip rings 7a, b, c, d, e, f, g, which are arranged in circumferential grooves 8a, b, c, d, e, f, g of the drive shaft 3. The slip rings 7a-g are formed from plastic, particularly an inherently stable plastic, so that they contact the bushing 4 like piston rings. The bushing 4 provides sealing sections 9a, b, c, d, e, f, g as contacting areas at its inside in the form of circumferential cylinder jacket sections.
The guide wheel section 2 shows recesses 10a, b as well as lubricant channels 11a, b, each of which being formed as fluid areas for a lubricant. The recess 10a extends in the axial direction over the channel sections 6a, b, c and partially d. The recess 10b is aligned congruent in reference to the recess 6e. The recess 10a is embodied limited in the circumferential direction. The recesses 10a, b each extend for example over an angular range of less than 40 degrees, preferably less than 30 degrees. The bushing 4 partially covers the recess 10a, b so that by the bushing 4 and the guide wheel section 2, particularly the recess 10a, a lubricant channel structure is formed.
The bushing 4 comprises penetrating openings 12a, b, c, d, e, f, with the fluid area of the recess 10a being able to communicate with an annular chamber 13 about the drive shaft 3 via the penetrating opening 12a. Further, the recesses 6a, b, c can communicate via the penetrating openings 12b, c, d with the fluid area 10a such that a distribution structure is formed for the lubricant. The recess 6d communicates, however, via the penetrating opening 12e with the lubricant channel 11a, the recess 6e communicates via the penetrating opening 12f and the recess 10b with the lubricant channel 11b.
The lubricant guiding and distribution structures shown shall be understood as mere examples; depending on the strategy for lubricant distribution, by the cooperation of the recesses 6a-e, 10a, b with the lubricant channels 5a, b, 11a, b via the penetrating openings 12a-f, arbitrary strategies can be implemented.
The bushing 4 may enter into a force-fitting connection with the guide wheel section 2 only in the areas of the guide wheel section 2, at which no recesses 10a, b or lubricant channels 11a, b are provided. Without any additional measures this would lead, however, to the sections of the bushing 4, supported by the guide wheel section 2 and not supported by the recesses 10a, b and/or lubricant channels 11a, b, being able to assume a different radial position. By the different radial offset of these sections of the bushing 4 out-of-roundness and thus a lack of smooth operation of the drive shaft 3 would develop in the bushing 4. For this reason, the bushing 4 comprises sections with different wall thicknesses, as explained in the context of
Corresponding, particularly overlapping, in particular congruent to the recesses 10a, b and/or to the other recesses about the lubricant channels 11a, b, the bushing 4 shows coupling sections 15a, b, c, which are equivalent in the form of their extension to the recesses 10a, b and/or the other recesses. This way, the recess 10a is formed by an area section extending in the axial direction and limited in the circumferential direction. The coupling section 15a extends in the same way in the axial direction and is limited in the circumferential direction about the primary axis H.
A neighboring section 16a abuts at the coupling section 15a, which is formed in this example by the basic body 14 of the bushing 4 without the coupling section 15a. The wall thickness (or wall strength) of the coupling section 15a is embodied greater than the wall thickness of the neighboring section 16a so that the yielding of the bushing 4 in the area of the recess 10a is compensated by thicker material and this way a constant internal diameter of the bushing 4 is achieved in the installed state in
A coupling section 15b extends in the form of a ring circumferential about the primary axis of rotation H, with the penetrating opening 12e being arranged in the coupling section 15b. Here, the planar extension of the coupling section 15b at the planar extension of the additional recess, allocated to the penetrating opening 12e, is compensated. In the axial direction, next to the coupling section 15b, on the one hand the neighboring section 16a is arranged and on the other hand a neighboring section 16b. Here it also applies that the wall thickness of the coupling section 15b is slightly greater than the wall thickness of the neighboring sections 16a, b, in order to ensure sufficient roundness in the installed, particularly impressed situation.
In the same fashion, a coupling section 15c is formed, which also shows an annular form, and which is limited axially by the neighboring sections 16b and 16c at the sides.
Although by the reinforcement of the wall thicknesses in the coupling sections 15a, b, c a high degree of roundness is achieved, similar to the exemplary embodiment in
The bushing 4 provides a circumferential track section 18 at its interior for the roller bearing device 17. At the interior circumference the roller bearing device 17 shows a counter track 19, which is formed by the basic material of the drive shaft 3. In particular, the roller bearing device 19 is arranged in a circumferential groove 20 or a recess of the drive shaft 3.
The bushing 4 is formed as a drawn bushing made from metal, with regard to manufacturing. This way, during the production, starting with a planar sheet, particularly a rhomb, a socket is drawn with a socket bottom. This way, the socket and also the resulting bushing 4 show a flange end 21 and a tension end 22, with the tension end 22 marking the end of the socket with the socket bottom and the flange end 21 marking the end with the flange. For example, the flange end 21 may be held down by a press pad. In the resulting bushing 4 both the flange as well as the socket bottom have been removed.
The track section 18 is arranged at the tension end 22 because this end shows a higher quality with regard to roundness. While at the flange end 21 the processing window is limited by the generation of folds due to the lack of press pads or insufficiently strong ones, and thus in the edge region of the process window folds and thus out-of-roundness areas develop, the tension end 22 is threatened by bottom tears, namely at the edge of the process window, however if such bottom tears do not arise, which can be ensured by simple monitoring, the degree of roundness is very high so that the support of the driven shaft 3 is better implemented via the roller bearing device 17 at the tension end 22 than at the flange end 21.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102014204571.1 | Mar 2014 | DE | national |
