Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D3/00—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive
  • F16D3/16—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts
  • F16D3/20—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members
  • F16D3/22—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members the rolling members being balls, rollers, or the like, guided in grooves or sockets in both coupling parts
  • F16D3/223—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members the rolling members being balls, rollers, or the like, guided in grooves or sockets in both coupling parts the rolling members being guided in grooves in both coupling parts
  • F16D3/2237—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members the rolling members being balls, rollers, or the like, guided in grooves or sockets in both coupling parts the rolling members being guided in grooves in both coupling parts where the grooves are composed of radii and adjoining straight lines, i.e. undercut free [UF] type joints
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D3/00—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive
  • F16D3/16—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts
  • F16D3/20—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members
  • F16D3/22—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members the rolling members being balls, rollers, or the like, guided in grooves or sockets in both coupling parts
  • F16D3/223—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members the rolling members being balls, rollers, or the like, guided in grooves or sockets in both coupling parts the rolling members being guided in grooves in both coupling parts
  • F16D2003/22303—Details of ball cages
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D3/00—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive
  • F16D3/16—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts
  • F16D3/20—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members
  • F16D3/22—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members the rolling members being balls, rollers, or the like, guided in grooves or sockets in both coupling parts
  • F16D3/223—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts one coupling part entering a sleeve of the other coupling part and connected thereto by sliding or rolling members the rolling members being balls, rollers, or the like, guided in grooves or sockets in both coupling parts the rolling members being guided in grooves in both coupling parts
  • F16D2003/22313—Details of the inner part of the core or means for attachment of the core on the shaft
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D2300/00—Special features for couplings or clutches
  • F16D2300/06—Lubrication details not provided for in group F16D13/74

Definitions

• the invention relates to an inner joint part for a constant velocity universal joint, said inner joint part having a plurality of circumferentially distributed ball tracks for guiding torque transmitting balls. Furthermore, the invention relates to a constant velocity universal joint which, in addition to such an inner joint part, comprises an outer joint part with outer ball tracks, also torque transmitting balls which are each held in pairs of outer and inner ball tracks, as well as a ball cage in which the balls are held.
• constant velocity universal joints serve to transmit torque between the inner joint part and the outer joint part, with angular movements of the inner joint part being permitted relative to the outer joint part.
• constant velocity fixed joints wherein the inner joint part is largely axially fixed relative to the outer joint par
• constant velocity plunging joints wherein the inner joint part is able to carry out axial plunging movements relative to the outer joint part.
• constant velocity joints can comprise different track shapes, such as straight ball tracks or curved ball tracks.
• Document DE 10 2005 023 045 A1 describes a constant velocity universal joint which comprises an outer joint part, an inner joint part, torque transmitting balls as well as a cage in which the balls are held.
• the ball tracks are unevenly spaced around the circumference, so that between adjoining ball tracks there are provided webs of different widths.
• the webs of a smaller width at one axial end are reduced in height relative to a ball face enveloping the webs in order to reduce the risk of fracture.
• Document DE 195 14 868 C1 describes a further constant velocity universal joint with an outer joint part, an inner joint part, torque transmitting balls and a ball cage.
• a first group of guiding webs is delimited along the entire axial length of the inner joint part by a spherical surface.
• a second group of guiding webs, at its axial end with the greater track depth, is reduced to a contour below the respective spherical surface. It is intended, in this way, to achieve improved mounting conditions and, related thereto, an increased strength of the ball cage.
• Document DE 10 2005 063 006 A1 describes an inner joint part for a constant velocity universal joint in the form of a plunging joint, as well as a method of producing an inner joint part.
• the inner joint part comprises a plurality of circumferentially distributed webs which form spherical guiding faces for a ball cage.
• the ball tracks each comprise a hard-machined first track portion and an unmachined second track portion.
• Document WO 2006/058556 A1 proposes a method of machining an inner joint part of a constant velocity universal joint wherein at least one ball track and at least one guiding web are machined simultaneously.
• ball cages are not ideally round, but comprise a shape which slightly deviates from the circular shape. This means that the ball cage is positioned with pretension on the inner joint part and therefore is subjected to external forces, even in the unloaded condition, which, in turn, leads to friction and heat losses.
• a further object consists in proposing a constant velocity universal joint which comprises such an inner joint part.
• an inner joint part for a constant velocity universal joint comprising a plurality of circumferentially distributed ball tracks for receiving torque transmitting balls, and a plurality of circumferentially distributed first webs and second webs which are formed between two circumferentially adjoining ball tracks, wherein the first webs define an enveloping spherical face K of the inner joint part with a diameter D, and wherein the second webs, each along their entire axial length L, are spaced inwardly from the enveloping spherical face K of the inner joint part.
• the advantage of the inventive inner joint part consists in that the outer faces of the second webs are set back inwardly relative to the outer faces of the first webs. In this way, the circumferential regions of the second webs are provided with a certain radial play relative to the ball cage which leads to a reduction in the forces which act between the inner joint part and the outer joint part when the constant velocity universal joint is in operation and thus to a reduction in the friction and performance losses.
• the forces acting on the ball cage are due to the fact that, because of hardness distortions and production tolerances, the ball cage, as a rule, is not ideally round, but slightly deviates from the circular shape.
• the ball cage in its mounted condition, comprises a certain freedom of movement because it is guided by the longer first webs only, which means that in the unloaded condition of the constant velocity universal joint, for instant in the articulated condition when no torque is transmitted, the forces acting on the ball cage are clearly reduced.
• under load especially when torque is transmitted when angular movements take place, it is ensured that the ball cage, by means of its inner face, is able to be supported on the second webs reduced under the spherical face K, and is guided by same.
• the inner joint part is produced in the form of a forged precision blank which, in respect of the end contour to be produced, already comprises a high degree of production accuracy, so that the final machining process of the second webs can be eliminated. Only the carrying first webs have to undergo a final machining process, which leads to a shortened production time and to a reduction in production costs.
• the inventive inner joint part makes it possible to reduce friction and performance losses, which, in the final analysis, has a positive effect on the fuel consumption of the motor vehicle. Furthermore, the inner joint part can be produced easily and cost-effectively.
• the number of first webs corresponds to the number of second webs.
• the number of first webs it is also possible for the number of first webs to deviate from the number of second webs, with the number of the first webs always having to be selected to be such that the ball cage is well supported around the entire circumference.
• the first and the second webs are preferably uniformly distributed around the circumference, for example with two adjoining first webs being followed by a second web. To ensure symmetric supporting conditions it is advantageous if the first and second webs are alternately arranged around the circumference.
• the contours of the outer faces of the first webs and the contours of the outer faces of the second webs are of identical design, if shown in a cross-sectional view.
• This is advantageous in that the outer faces of the first and of the second webs can be produced by the same tool, wherein, during the production of the second webs, only the feed has to be changed accordingly in the radial direction with reference to the axis of rotation of the inner joint part.
• the outer contours of the first webs to differ from the outer contours of the second webs, if viewed in cross-section.
• the outer faces, at least of the first webs are rounded in their regions of transition to the ball tracks.
• the rounded webs produced to avoid edge contact is advantageous more particularly in combination with the set-back second webs, because both features lead to a uniform advantage of a reduction in the performance losses of the joint.
• the outer faces at least of the first webs form guiding faces with a radius R, which guiding faces define the enveloping spherical face K and serve to guide the ball cage, as well as free faces which laterally adjoin the guiding faces in the circumferential direction and which free faces are radially inwardly set back relative to the enveloping spherical face K and relative to the guiding faces.
• the guiding faces are formed by a first portion of the outer face, which first portion is positioned on the spherical face K.
• This first portion in a cross-sectional view, is followed by the second portions which are arranged at a radial distance from the spherical face K and form the so-called free faces.
• This embodiment is advantageous in that the guiding face is small relative to the entire outer face of the respective web, so that the contact face with the ball cage is also correspondingly small. In this way, the friction forces acting between the guiding faces of the inner joint part and the inner face of the ball cage are reduced, which results in improved guidance of the ball cage relative to the inner joint part.
• the free faces which are set back relative to the enveloping spherical face help to reduce the friction forces because radial gaps are formed between the free faces and the inner face of the ball cage and allow lubricant to enter. Depending on the contour of the outer face, the lubricant can enter deeply into the gap in order to lubricate the contact faces between the webs and the ball cage.
• the outer faces of the first and second webs can have axial and radial contours, and, while taking into account the surface pressure effective between the inner joint part and the ball cage, the guiding faces can be as small as desired, because the smaller the guiding faces and the larger the free faces, the lower the friction forces and the better the lubricant supply and the guidance of the ball cage.
• the inventive design of the first and second webs with (in a cross- sectional view) first portions provided for guiding purposes and second portions offset inwardly relative to the ball face there is obtained a defined contour of the webs which, in turn, leads to improved carrying conditions.
• the first outer faces, in a cross-sectional view are symmetrical with reference to a plane of symmetry S, with the guiding face being positioned in the region of the plane of symmetry S and with the free faces being arranged so as to laterally adjoin the guiding face in the circumferential direction.
• the ratio of the extension B 1 of the first portion in the circumferential direction to the total extension B of the outer face in the circumferential direction is smaller than two thirds, i.e. B 1 ZB ⁇ 2/3, more particularly smaller than half, i.e. Bi/B ⁇ 1/2, more particularly smaller than one third, i.e. B 1 ZB ⁇ 1/3.
• the outer face of the webs in a cross-sectional view is formed by radii; in principle, the outer contour can also be formed by curves of a higher order.
• the first portion and the second portion in a cross-sectional view are formed by a circular arch whose radius R A remains constant along the length.
• the radius R A is preferably smaller than half the diameter D/2 of the enveloping ball face K. In a cross-sectional view, this results in a point contact or, because of the surface pressure, a minimum surface contact between the outer face of the inner joint part and the inner face of the ball cage.
• the radius R A is greater than/equal to a quarter of the diameter D, i.e. R A ⁇ D/4.
• the advantage of the present embodiment with a constant radius R A is that the gap between the outer face of the inner joint part and the inner face of the ball cage is maximised, thus allowing lubricant to enter particularly deeply as far as the central region of the webs.
• the continuous transition of the first and second portion - due to the same radius - also advantageously contributes towards the lubricant entering deeply into the gap.
• the first portion comprises a first radius R A1 which is smaller than/equal to half the Diameter D of the enveloping ball face, i.e. R A1 ⁇ D/2 and that the second portion of the outer face comprises a second radius R 1 ⁇ 2 which is smaller than the first radius R A1 of the first portion, i.e. R / ⁇ ⁇ R A1 .
• the ratio of the extension B 1 of the first portion in the circumferential direction to the entire extension B of the outer face in the circumferential direction ranges between one third and two thirds, i.e. 1/3 ⁇ B 1 ZB ⁇ 2/3.
• the webs of said second embodiment comprise larger guiding faces and a higher percentage of carrying portions. This is particularly advantageous for constant velocity joints in which the surface pressure between the inner joint part and the ball cage is higher.
• the webs in a cross-sectional view, comprise chamfers in the region of transition between the outer face and the adjoining ball tracks.
• the chamfers are provided in inner joint parts wherein the dimension of the gap between the second portions of the webs and the inner face of the ball cage and the enveloping spherical face respectively is small.
• the chamfers prevent any material removed by the rolling movement of the balls in the ball tracks from moving radially outwardly, which would lead to more friction and wear.
• the chamfers can be produced at the same time as the outer contour. Therefore, there is no need for a separate production process specially for manufacturing the chamfers.
• first and second webs of the inventive inner joint part can generally have any design in the longitudinal direction inside the enveloping ball face.
• the outer contours of the first webs and the outer contours of the second webs can be identical in design, or the first webs can comprise outer contours which deviate from the outer contours of the second webs in a longitudinal section.
• the outer faces of the first and/or of the second webs - if viewed in a longitudinal section - can be formed by a circular arch whose radius R L is smaller than or equal to half die diameter D of the enveloping ball face, i.e. R L ⁇ D/2, with the guiding face at least of the first webs extending along the entire length of the inner joint part, so as to bear loads along the entire length of the ball cage.
• the guiding faces of the first and/or the second webs are designed in such a way that the ball cage, if viewed in a longitudinal section, is guided on two end regions of the respective webs.
• the outer faces of the webs in the central region each comprise a flattened portion, so that two end regions for guiding the ball cage are formed and positioned so as to axially adjoin the flattened portion.
• the outer contours of the end regions are preferably formed by a circular arch whose radius R L is smaller than or equal to half the diameter D of the enveloping ball face, i.e. R L ⁇ D/2, and the smaller the radius R L , the smaller the contact face between the inner joint part and the ball cage.
• This embodiment with two lateral end regions which guide the ball cage can also be referred to as a roof shape.
• the load bearing end regions can also be formed by conical faces instead of radii.
• At least one of the second webs can be shaped in such a way that the process of mounting the inner joint part in the ball cage is simplified.
• this at least one second web, at one axial end can comprise a reduced region which extends from the guiding face a far as the end face of the inner joint part.
• the reduced portion can be provided in the form of a conical flattened portion.
• said second web can be flattened in a central axial region, so that, even under load, it no longer has a guiding function relative to the ball cage.
• the guiding function could, under load, optionally be assumed by the end regions.
• two opposed second webs could be provided with such flattened portions for mounting purposes, with said two second webs preferably being arranged diametrically opposite one another.
• a constant velocity universal joint comprising an outer joint part with outer ball tracks; an inner joint part with inner ball tracks; torque transmitting balls which are guided in pairs of tracks, each pair consisting of an outer ball track and an inner ball track; a ball cage with windows in which there are received the torque transmitting balls; wherein the inner joint part is designed in accordance with any one of the above embodiments.
• the inventive constant velocity joint can have any design. RF joints, UF joints, counter track joints as well ad DO joints are particularly suitable.
• the main advantage of the inventive constant velocity joint consists in that the outer faces of the second webs are inwardly set back relative to the outer faces of the first webs. In this way, the entire guiding face for guiding the ball cage is reduced in size, so that, when the joint is in operation, the forces acting on the ball cage are clearly reduced. This, in turn, leads to a reduction in the friction forces between the contact faces contacting one another and to a reduction in performance losses
• half the diameter D of the enveloping spherical face of the inner joint part is smaller than or equal to a spherical inner face of the ball cage This measure also contributes towards a reduction in friction
• Figure 1 shows an inventive inner joint part in a first embodiment a) in an axial view, b) in a side view, c) in a longitudinal section along sectional line C-C of Figure 1 a), d) a first web according to Figure 1 a in the form of a detail in a cross-sectional view, with the ball cage drawn in
• Figure 2 shows an inventive inner joint part in a second embodiment a) in an axial view, b) in a side view, c) in a longitudinal section along sectional line C-C of Figure 2a), d) a first web according to Figure 2a in the form of a detail in a cross-sectional view, with the ball cage drawn in
• Figure 3 shows an inventive inner joint part in a third embodiment a) in an axial view, b) in a side view, c) in a longitudinal section along sectional line C-C of Figure 3a), d) a first web according to Figure 3a in the form of a detail in a cross-sectional view, with the ball cage drawn in
• Figure 4 shows an inventive inner joint part in a fourth embodiment a) in an axial view, b) in a side view, c) in a longitudinal section along sectional line C-C of Figure 4a), d) a first web according to Figure 4a in the form of a detail in a cross-sectional view, with the ball cage drawn in Figure 5 shows an inventive inner joint part in a fifth embodiment a) in an axial view, b) in a side view, c) in a longitudinal section along sectional line C-C of Figure 5a), d) a first web according to Figure 5a in the form of a detail in a cross-sectional view, with the ball cage drawn in
• Figure 6 shows an inventive inner joint part in a sixth embodiment a) in an axial view, b) in a longitudinal section along sectional line B-B of Figure 6a),
• Figure 7 shows an inventive inner joint part in a seventh embodiment a) in a cross-sectional view b) in a longitudinal section according to sectional line B-B of Figure 7a)
• Figure 8 shows a constant velocity universal joint in the form of a fixed joint with an inventive inner joint part a) in a longitudinal section, wherein the sectional line in the upper half of the Figure extends through a ball track and in the lower half of the Figure through a web, b) a first web according to Figure 8a in the form of a detail in a cross-sectional view with the ball cage
• Figure 9 shows an inventive inner joint part in a further embodiment in an axial view
• Figure 10 shows a constant velocity universal joint in the form of a fixed joint with an inventive inner joint part according to Figure 9 a) in an axial view, b) in a longitudinal section according to sectional line B-B of Figure 10a)
• FIG. 1 to 5 will be described jointly below as far as the features are concerned which they have in common, with identical components having been given the same reference numbers and the reference numbers of modified components have been provided with subscripts corresponding to the respective Figures
• an inner joint part 2 for a constant velocity universal joint described in greater detail below
• the constant velocity universal joint comprises an outer joint part, a ball cage and torque transmitting balls which are held in windows of the ball cage
• the inner joint part 2 comprises a plurality of circumferentially distributed first webs 3', a plurality of circumferentially distributed second webs 3" as well as a ball track 4 arranged between two circumferentially adjoining webs 3
• the ball tracks 4 serve to receive and guide the torque transmitting balls of the constant velocity universal joint
• the webs 3 each comprise an outer face 5 which will be described in greater detail below
• the inner joint part 2 comprises a first end face 6, an end face 7 which is positioned axially opposite thereto, as well as a central through-aperture 8
• the through-aperture 8 comprises inner teeth (not illustrated) into which, for torque transmitting purposes, there can be inserted a shaft or a journal in a rotationally fixed way
• the greatest radial extension of the outer faces 5 of the webs 3 comprise an imaginary spherical face K which envelopes the inner joint part 2 and which is also referred to as an enveloping spherical face K
• the inner joint part is asymmetric in a longitudinal section, in so far as a plane E which, in the centre of curvature O of the spherical face, is positioned perpendicularly relative to the longitudinal axis A, divides the inner joint part 2 into two portions of unidentical axial lengths
• the ball tracks 4 extend parallel to the longitudinal axis A
• the number of ball tracks 4 depends on the number of torque transmitting balls to be used Normally, constant velocity universal joints for the driveline of motor vehicles are provided with six or eight balls, but different numbers of balls are also conceivable Between each two ball tracks 4, there is formed a web 3, so that, overall, the number of webs corresponds to the number of ball tracks
• the inner joint part 2 comprises two groups of webs 3 whose webs differ from one another There is provided a first group of first webs 3' whose outer faces 5', in a cross-sectional view, at least by means of a partial portion, radially extend as far as the enveloping spherical face K In the assembled condition of the inner joint part 2, the first webs 3' are in contact with the ball cage (not illustrated here) for the purpose of guiding same
• the webs of the second group which are also referred to as second webs 3" are radially inwardly set back along their entire length L relative to the enveloping face K, so that the outer faces 5" of the second webs 3" are arranged at a radial distance from the enveloping spherical face
• radial gaps are formed between the outer faces 5" of the second webs 3" and the spherical inner face of the ball cage (not shown), in the load-free condition of the joint, the second webs 3" are not in contact with the ball cage
• the ball cage whose shape, because of production tolerances and hardness distortions, may deviate from the ideally round shape, is able to retain its shape in the mounted condition because the set-back second webs 3" provide a sufficient amount of space
• the outer contours of the first webs 3' and of the second webs 3" are identically shaped, the advantage being that, if the ball cage when the joint is torque-loaded, also comes into contact with the second webs 3" and is radially supported against same, there are achieved uniform load bearing conditions between the inner face of the ball cage on the one hand and the first webs 3' and, respectively, the second webs 3" on the other hand
• the outer contours of the second webs 3" deviate in shape from the outer contours of the first web 3', which applies both to the cross-section and to the longitudinal section
• the inner joint part 2 in the present embodiments according to Figures 1 to 5 comprises six ball tracks 4 and, accordingly, six webs 3, wherein the webs of the first group, i e the first webs 3', and the webs of the second group, i e the second webs 3", are arranged so as to alternate around the circumference
• This measure ensures in an advantageous way that the ball cage is supported in three regions across the circumference, which ensures accurate centring of the ball cage coaxially relative to the inner joint part 2
• the inner joint part 2 can also comprise any other number of ball tracks 4 and webs 3, more particularly eight
• the arrangement of the first and second webs 3', 3" can also differ from an alternating arrangement For example, it is also possible for two first webs 3' to adjoin one another which, in the circumferential direction, are followed by a second web 3"
• the outer faces 5', 5" of the first and second webs 3', 3" in a cross-sectional view comprise a radius R which, approximately corresponds to half the diameter D of the enveloping spherical face K or is slightly smaller than same, i e R ⁇ D/2
• the regions of transition between the outer faces 5', 5" and the adjoining ball tracks 4 are formed as rounded portions 25
• the rounded portions 25 prevent the ball cage from being supported on the edges of the webs, more particularly of the first webs 3'
• the risk of edge support is less pronounced because these are reduced in size radially inwardly relative to the first webs 3'
• the outer contour of the first webs 3' corresponds to the outer contour of the second webs 3", i e the second webs 3" are radially inwardly offset merely by a defined dimension
• the radial gap which is thus produced between the outer faces 5" of the second webs 3" and the inner face of the ball cage
• the first and second outer faces 5', 5" in a cross-sectional view, each comprise a first portion 9' for guiding the ball cage, as well as two laterally adjoining second portions 10' which are spaced inwardly from the enveloping ball face K
• the guiding face 12 which is defined by the first portions 9 along the length of the web, between the inner joint part 2 and the ball cage (not illustrated) is small relative to the entire outer face 5, so that the friction forces acting between said two components are low.
• the free faces which are defined by the second portions 10' along the length of the web are large relative to the entire outer face 5.
• first and second webs 3' , 3" are identical, which is advantageous in that they can be produced by the same tool.
• first and second webs 3', 3" in a cross-sectional view, comprise different contours.
• the first portions 9 and the laterally adjoining second portions 10 are formed by a common uniform radius R A .
• substantially linear in this context means that because of the surface pressure, the contact is not a pure linear contact, but a narrow surface contact in the circumferential direction.
• the second portions 1O 3 which, in the circumferential direction, continuously adjoin the first portion 9 3 on opposed sides, comprise a second radius R ⁇ which is smaller than the first radius RA 1 of the first portion 9 3 .
• the guiding face 12 3 formed by the first portion 9 3 if viewed in the longitudinal direction, is approximately strip-like, which is particularly obvious from Figure 3b.
• the width B1 of the guiding face 12 3 formed in this way is approximately half the size of the entire extension B of the outer face 5 3 in the circumferential direction in the region of the side face of the inner joint part.
• the surface pressure between the webs 3 3 of the inner joint part 2 3 and the ball cage 14 has been reduced compared to the above embodiment according to Figure 2.
• the embodiment shown in Figure 4 largely corresponds to that shown in Figure 3, so that, a far the common features are concerned, reference is made to the description of Figure 3.
• first and the second webs 3 4 ', 3 4 " at their ends arranged opposite one another in the circumferential direction, each comprise a chamfer 15, which chamfers 15 form a transition from the respective ball track 4 to the second portion 10 4 of the outer face 5 4
• the chamfers 15 prevent any material removed when the joint is in operation as a result of the rolling movement of the ball in the ball tracks 4 from moving radially outwardly. This could lead to the respective gap 16 between the respective web 3 4 and the inner face 13 of the ball cage 14 becoming blocked.
• the chamfer 15 ensures that, even after a long period of operation, lubricant can enter the gap 16 and lubricate the faces which contact one another. This has an advantageous effect on the service life of the joint.
• the embodiment shown in Figure 5 largely corresponds to that shown in Figure 3, so that, as far as the common features are concerned, reference is made to the description of Figure 3.
• the outer faces 5 5 of the first and second webs 3 5 ', 3 5 " of the present embodiment comprise flattened portions 17 in an axially central region. In said flattened regions, the webs 3 5 are not in contact with the inner face 13 of the ball cage 14. On the contrary, if viewed in a longitudinal section, there is achieved a two- point contact, which is particularly obvious from Figure 5c, with the supporting first portions 9 5 of the webs 3 5 being positioned in axial end regions of the inner joint part 2 5 .
• the flattened portions 17 once more reduce the size of the contact face between the outer face 5 5 of the inner joint part 2 5 and the inner face 13 of the ball cage 14, which has an advantageous effect on friction.
• a further advantage consists in that the inner joint part 2 5 is well supported relative to tilting movements around the axis of articulation of the joint.
• the second webs 3 in respect of their outer contour, are offset radially inwardly relative to the enveloping spherical face K. This means that in its load-free condition, the ball cage is primarily carried by the first webs 3 5 ', but, when torque-loaded, it can also be supported on the second webs 3 5 ".
• the generating radius R L is preferably smaller than or equal to half the diameter D of the enveloping ball face, i.e. R L ⁇ D/2. It goes without saying that the modification to the inventive inner joint part with flattened portions can be applied to any outer surface contour. More particularly, the embodiments according to Figures 1 , 2 or 4 are conceivable and comprise flattened portions according to the embodiment shown in Figure 5. To complete the scenario, it should also be mentioned that the first and second webs 3', 3" can also deviate from one another in respect of their outer contour in the longitudinal direction.
• the supporting first webs 3' in the longitudinal section comprise a roof- like contour as shown in Figure 5 and that the set-back second webs 3" comprise an arch-like outer contour with a constant radius R L along their length, as illustrated in Figures 1 to 4 for instance.
• Such an embodiment would be advantageous in that the cage would exhibit a good supporting behaviour as a result of the first webs, while at the same time the second webs would be easy to produce.
• Figure 6 shows an inventive inner joint part 2 6 in a modified form.
• the inner joint part 2 6 can be designed in accordance with any one of the individual above-described embodiments.
• the special feature of the present embodiment consists in that the second webs 3 6 " comprise reduced portions 18 for the cage assembly on the same axial side of the inner joint part 2.
• the reduced portions 18 which are provided in the form of edge fractures of the end edge and can also be referred to as flattened assembly portions permit an easy assembly without reducing the strength of the cage, as described in the above- mentioned DE 195 14 868 C1.
• the region of the second webs 3 6 " which axially adjoins the reduced portion is radially set back relative to the enveloping spherical face K, so that a radial gap is formed between the second webs 3 6 " and the ball cage along the entire length.
• the first webs 3 6 ' do not comprise reduced portions 18 and can all be given a uniform design according to each of the above-mentioned embodiments. It is possible for one single second web or two second webs or even all second webs to comprise said reduced portions 18. To provide all the second webs with correspondingly reduced portions is advantageous in that it achieves a uniform distribution of masses, which, in turn, leads to a slight out-of-balance.
• FIG. 7 shows a further variant of an inventive inner joint part 2 7 , and the webs 3 7 ' can also be designed in accordance with one of the above-mentioned embodiments according to Figures 1 to 5
• the special characteristic of the present variant is that two opposed second webs 3 7 " comprise reduced portions 18 7 which are provided in the form of central flattened assembly portions
• the end regions of the respective second webs 3 7 " are formed by radii, with the outer faces 5 7 " of the end regions being radially set back relative to the enveloping spherical face K, so that a radial gap is formed between the second webs 3 7 " and the ball cage along the entire length
• the present embodiment, too, with central flattened assembly portions offers the advantage of simplifying the operation of mounting the inner joint part 2 7 in the associated inner ball cage without losing any strength and at the same time improving the guidance of the cage due to reduced friction forces
• FIG 8 shows an inventive constant velocity joint with an inventive inner joint part in the embodiment according to Figure 2
• the constant velocity universal joint is provided in the form of a Rzeppa fixed joint which, therefore, is also referred to as a RF joint
• the Rzeppa joint serves to transmit torque between two rotating components, with angular movements being possible between the two components
• the constant velocity fixed joint comprises an outer joint part 21 with outer ball tracks 22, an inner joint part 2 with inner ball tracks 4, torque transmitting balls 23 which are guided in pairs of tracks consisting of one outer and one inner ball track 22, 4, as well as a ball cage 14 with circumferentially distributed cage windows 24 receiving the balls 23
• the balls 23 are held by the ball cage 24 in a common central plane E and when the joint is articulated they are guided on to the angle-bisecting plane between the outer joint part 21 and the inner joint part 2
• the special feature of the present Rzeppa fixed joint consists in that the outer contours of the first and of the second webs 3', 3" of the inner joint part 2 are designed according to the embodiment shown in Figure 2
• at least the first webs 3' in a cross-sectional view each comprise portions 9' for guiding the ball cage and, if viewed in the circumferential direction, adjoining second portions 10' which are radially inwardly set back relative to the inner face 13 of the ball cage 14
• the inner joint part of the Rzeppa fixed joint as illustrated can, of course, also comprise webs with outer contours as shown in Figures 1 or 3 to 7
• Figure 9 shows an inventive inner joint part 2 9 in a further embodiment which largely corresponds to that illustrated in Figure 2
• the present inner joint part comprises a total of eight ball tracks 4 9 and eight webs 3 9
• first webs 3 9 ' and four second webs 3 9 " which are alternately arranged around the circumference
• the cage more particularly in the load-free condition, if viewed in a cross-sectional view, is supported in four points which are each offset by 90° around the longitudinal axis
• the ball cage is well supported on the inner joint part
• any out-of-balance is avoided because of the different radial extension of the first and second webs 3 9
• Figure 10 shows an inventive constant velocity universal joint in a further embodiment with an inventive inner joint part in the embodiment according to Figure 9
• the present constant velocity universal joint in many respects corresponds to that shown in Figure 8, so that as far as the common features are concerned, reference is made to the description of Figure 8 Details which are identical or correspond to one another have been given the same reference numbers but provided with the subscript "10" Below, there will follow a description of the differences
• the present constant velocity universal joint is provided in the form of a so-called UF fixed joint wherein the ball tracks 22 10 , 4 10 - if viewed in a longitudinal section - are undercut-free along their length
• the ball tracks 22 10 , 4 10 each comprise a straight track portion and an adjoining arch-shaped track portion
• a further difference consists in that the present joint, overall, comprises eight torque transmitting balls and, accordingly, eight outer tracks and eight inner tracks
• the inner joint part 2 10 corresponds to the inner joint part shown in Figure 9 to the description of which reference is therefore made
• inventive constant velocity universal joints shown in Figures 8 and 10 serve as examples in order to show in which type of joints the inventive inner joint parts 2 can be used
• teaching in accordance with the invention regarding the inner joint parts 2 with set-back webs applies to all constant velocity universal joints wherein the ball cage is guided on the preferably spherical guiding face of the inner joint part 2
• All said constant velocity universal joints with inventive inner joint parts are advantageous in that the radially shortened second webs, in the mounted condition, are freed relative to the ball cage More particularly, in the load-free condition of the constant velocity universal joint, this leads to a definite reduction in the friction forces acting between the ball cage and the inner joint part However, under load, it is ensured that the ball cage is able to be supported on the second webs, so that the technical function of the joint is fully guaranteed Overall, the inner joint part in accordance with the invention makes it possible to reduce friction forces and performance losses, which, in the final analysis, has a positive effect on the fuel consumption of the motor vehicle

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Bearings For Parts Moving Linearly (AREA)
• Rolling Contact Bearings (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=40547827

Family Applications (1)

Country Status (2)

Citations (4)

Family Cites Families (11)

• 2008
  • 2008-08-28 DE DE102008044657.2A patent/DE102008044657B4/de active Active
  • 2008-12-02 WO PCT/EP2008/010192 patent/WO2010022761A1/en active Application Filing

Patent Citations (4)

Also Published As

Similar Documents

Legal Events