Abstract:
A commercial vehicle has its axle housings supported on the chassis frame by way of spring elements. Each spring element is connected to a clamping yoke having two legs, of which in each case one leg rests against the front of the axle housing and the other leg rests against the rear of the axle housing, as seen in the driving direction. The legs are connected to one another by a web. Each leg is fixed and secured on a fixing projection on a longitudinal side of the axle housing, and the web is spaced apart from the upper side of the axle housing.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority, under 35 U.S.C. §119, of German patent application DE 10 2010 009 304.1, filed Feb. 25, 2010; the prior application is herewith incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     FIELD OF THE INVENTION 
     The invention relates to a commercial vehicle having an axle housing supported on the chassis frame by way of spring elements. Each spring element is connected to a clamping yoke having two legs. One leg rests against the front of the axle housing and the other leg rests against the rear of the axle housing, as seen in the driving direction. The two legs are connected to one another by way of a web. 
     An axle attachment means for sprung vehicle axles is described in German published patent application DE 10110495 A1. The axle attachment means has an axle housing, which is preferably designed as a square-section tube with rounded edges. Longitudinal links or leaf springs which cross the axle housing on the upper side or underside thereof are provided. Tension rods, which extend transversely to the longitudinal links or leaf springs and to the axle housing and pull said parts apart, are furthermore provided. The tension rods extend along the side walls of the axle housing and are supported on an axle lug resting against the outside of the axle housing. In addition, the tension rods are provided with at least one bend or offset along the longitudinal extent thereof. The disadvantage is that this way of securing the spring element on the axle housing subjects the axle housing to high vertical loads in the top area. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a vehicle which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which provides for the attachment of a spring to an axle housing in which the force of the spring element is introduced into the axle housing in a more advantageous way and the structure of the axle housing is thereby relieved of load. 
     With the foregoing and other objects in view there is provided, in accordance with the invention, a commercial vehicle, comprising: 
     an axle housing supported on a chassis frame by way of spring elements, the axle housing having a front and a rear relative to a driving direction of the vehicle, a longitudinal side, and an upper side; 
     the axle housing having a fixing projection formed on a longitudinal side thereof; 
     a clamping yoke connecting each of the spring elements, the clamping yoke having two legs and a web connecting the two legs to one another, one of the legs resting against the front of the axle housing and another of the legs resting against the rear of the axle housing; 
     each of the two legs being fixed on and secured to a respective the fixing projection on the axle housing, and the web being spaced apart from the upper side of the axle housing. 
     The term “commercial vehicle,” as used herein is substantially synonymous with “heavy duty vehicle” and includes transport and haulage vehicles, trucks, farm vehicles, military vehicles, and the like. 
     The invention comprises a clamping yoke which comprises at least two legs, which are connected to one another via at least one web, with an axle housing extending between the legs. In the installed condition, the clamping yoke spans the axle housing. In this arrangement, the spring element is fixed on the upper side of the web of the clamping yoke with the aid of clamping devices. The clamping devices are secured on the abutment or on the fixing projection of the axle housing. The clamping yoke is matched to the outer periphery of the axle housing of the commercial vehicle axle. The invention makes it possible to arrange a standardized clamping yoke on axle housings of different shapes and of differing diameters, allowing the clamping yoke to be used on axle housings with a hollow cross section, U sections or I sections. The items listed are given purely by way of illustration and are in no way intended to be exclusive. On the contrary, the clamping yoke according to the invention can be combined with any possible shape of axle housing. It is immaterial here whether the axle concerned is a live or a dead axle. The clamping yoke is advantageous since it can withstand high vertical forces and can fulfill other tasks, such as attachment of the longitudinal links, location of the shock dampers and attachment of the stabilizers. The invention makes it possible to arrange a very wide variety of spring elements on the axle housing. Examples which may be considered are leaf springs, coil springs, air springs or hydropneumatic spring systems in the form of hydraulic cylinders, for example. According to the invention, the web is at a distance from the axle housing in the installed condition. 
     In accordance with an additional embodiment of the invention, provision is made for an abutment, which spans the axle housing and at the same time connects the legs to one another, to be arranged on that side of the axle housing which faces away from the web, i.e., opposite from the web. The abutment provides additional anchoring for the clamping yoke on the axle housing. For this purpose, the abutment has lateral walls which extend at an angle to the base of the abutment and can be connected to the legs of the clamping yoke and/or to the web of the clamping yoke. To provide loss-proof connection between the abutment and the clamping yoke, the abutment and the clamping yoke can be screwed or clamped to one another. Other means of connection between the abutment and the clamping yoke are, of course, also possible. 
     At least one centering device is provided on the abutment and/or on the clamping yoke and/or on the fixing projection, allowing accurately positioned arrangement of the clamping yoke relative to the abutment or accurately positioned arrangement of the clamping yoke and/or of the abutment relative to the axle housing. It has furthermore proven advantageous to connect a spring element seated on the web of the clamping yoke not only to the clamping yoke but also to the abutment and to clamp the spring element thereto. This increases the strength of the assembled unit comprising the axle yoke and the spring element. 
     According to another embodiment of the invention, the fixing projection is arranged in the region of the neutral axis of the axle housing, i.e. arranged on the axle housing in the region of minimum bending. It is conceivable for the fixing projections to be secured on the axle housing horizontally or at an angle transversely to the driving direction. The fixing projections can be cast in one piece with the axle housing or, alternatively, can be welded to the axle housing. 
     In another embodiment of the invention, provision is furthermore made for a vertical force emanating from the spring element to be directed via the leg of the clamping yoke into the fixing projection of the axle housing. In this way, the spine of the axle housing is freed from the imposition of high vertical loads since the compressive load acting on the axle housing enters the axle housing homogeneously and laterally. Owing to the fact that the legs are connected to the fixing projections, the force of the spring element is not introduced directly from above into the spine of the axle housing. The spine of the axle housing is relieved of the vertical compressive load emanating from the spring element and this leads to a significant extension of the service life of the axle housing. The improvement in the introduction of vertical forces from the spring element into the axle housing makes it possible to use basic axle housing models which do not have to fulfill all functions, e.g. increased variability, yet have the required strength. The arrangement of fixing projections on axle housings with a trapezoidal cross section has proven particularly advantageous in this case. The width of the cross section of the axle housing increases from the top down. The vertical force emanating from the spring element flows via the legs of the clamping yoke into the fixing projections and, from there, into the wider lower region of the axle housing. In the case of axle housings made of cast iron, selective imposition of a compressive load in the spine of the axle housing and a tensile load in the lower region of the fixing projection is possible. The cast form and the trapezoidal cross section of the axle housing favor lateral introduction of vertical forces into the axle housing since the vertical forces can be introduced directly into the cast wall via the fixing projections. 
     Another conceivable way of optimizing the introduction of force into the axle housing is to make the fixing projection wedge-shaped, with the upper end of the fixing projection, that facing the web of the clamping yoke, forming a support surface for the leg, while the lower end of the fixing projection is tapered toward the wider, lower region of the axle housing. 
     In accordance with a concomitant feature of the invention, the underside of the leg and the profile of the fixing projection on which the leg rests are designed in such a way that mutual engagement between the underside of the leg and the fixing projection is possible. This ensures that the support profile can be secured on the fixing projection in a slip-proof manner. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a device for attaching a spring element to a commercial vehicle axle, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  shows an attachment device according to the prior art; 
         FIG. 2  shows an axle housing with the fixing projections according to the invention; 
         FIG. 3  shows a cross section through an attachment device on an axle housing; 
         FIG. 4  shows an axle housing with fixing projections and the clamping yoke with abutment in an exploded view; 
         FIG. 5  shows an axle housing with an attachment device in side view; 
         FIG. 6  shows the attachment device according to the invention in the installed condition, with a leaf spring system; 
         FIG. 7  shows a section corresponding to  FIG. 3  through an attachment device on an axle housing; and 
         FIG. 8  shows a longitudinal section through an axle housing in the region of attachment of the spring element. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the figures of the drawing in detail and first, particularly, to  FIG. 1  thereof, there is shown an attachment device for a spring element on an axle housing  2  of a commercial vehicle axle  3  for vibrationally decoupling the chassis frame of the vehicle from the vehicle axle  3  according to the prior art. In  FIG. 3 , the axle housing  2  has an approximately rectangular shape  24 , which accommodates the vehicle axle  3 . The number  27  indicates a receptacle for hub carriers. 
       FIG. 2  shows, in side view, the axle housing  2  of the commercial vehicle axle  3  with the differential axle case  22  and the fixing projections  8 . Provided on the fixing projections  8  and parallel to the fixing projections  8 , on the axle housing  2 , are centering devices  21 ,  25 , which allow accurately positioned arrangement of the clamping yoke  4  and of the abutment  9  relative to one another and relative to the axle housing  2 . Receptacles  27  for the hub carriers are provided at the two outer ends of the axle housing  2 . Visible above the fixing projection  8  is the spine  10  of the axle housing  2 , opposite which the lower region of the axle housing  2  is indicated by reference numeral  15 . An imaginary line  28  runs along the fixing projection  8  and divides the axle housing  2  into a spine  10  and a lower region  15 . The imaginary line  28  simultaneously marks the neutral axis  11 , namely the region of the axle housing  2  in which bending is at a minimum. 
       FIG. 3  shows a section through the axle housing  2  near the clamping yoke  4  and the abutment  9  of the attachment device according to the invention. In  FIG. 3 , the axle housing  2  is of trapezoidal design and has a spine  10  and a lower region  15 . When viewed in cross section, the axle housing  2  widens from the spine  10  toward the lower region  15 . Visible within the axle housing  2  is the axle  3  of the commercial vehicle. Fixing projections  8  are attached in the axial direction on the outer periphery of the axle housing  2 , approximately on the neutral axis  11  of the axle housing  2 . The fixing projections  8  divide the axle housing  2  into a spine  10  and a lower region  15 . At the upper end  16 , the fixing projection has a support surface  30 , on which the contact surface  18  of the leg  5  of the clamping yoke  4  (not shown) is supported. To optimize the vertical introduction of force  41  by the spring element  1  into the fixing projection  8  via the leg  5  of the clamping yoke  4 , the fixing projection  8  tapers from the upper end  16  thereof toward the lower end  17  thereof, with the result that the force is introduced into the downward-widening region  15  of the axle housing  2 . Centering devices  21  for accurately positioned arrangement of the clamping yoke  4  on the axle housing  2  are visible in  FIG. 3 . Arranged underneath the lower region  15  of the axle housing  2  is another centering device  25 , which is used to position the abutment  9  relative to the axle housing  2 . 
       FIG. 4  shows, in an exploded view, an axle housing  2  with a clamping yoke  4  arranged over the spine  10  of the axle housing  2  and an abutment  9 , which can be seen underneath the axle housing  2 . In this arrangement, the axle housing  2  has a differential axle case  22  for the differential gear and, at its outer end, a receptacle  27  for the hub carrier. The fixing projection  8  extends along the imaginary line  28  on the outer periphery of the axle housing  2 . The profile  14  of the fixing projection  8  exhibits an upper end  16 , a downward-tapering lower end  17  and a centering device  21 .  FIG. 4  shows the legs  5  of the clamping yoke  4 , between which the axle housing  2  extends. Extending between the legs  5  of the clamping yoke  4  to connect the legs to one another is the web  6 , which has a locating device  32  for a spring element  1  (not shown). Contact surfaces to enable the legs  5  to rest on the support surfaces  30  of the fixing projections  8  can be seen on the undersides  13  of the legs  5 . Likewise illustrated on the undersides  13  of the legs are studs  33 , which are used to position the legs  5  of the clamping yoke  4  on the centering device  21  of the fixing projection  8 . Contact surfaces  34  are arranged on the abutment  9  to enable the abutment  9  to rest against the axle housing  2 . The abutment  9  is centered relative to the centering device  21  of the fixing projection  8  by means of studs  35  on the abutment  9 . Screws (not shown) are provided to enable the clamping yoke  4  to be secured in a loss-proof manner on the abutment  9 . However, it is also conceivable to secure the clamping yoke  4  to the abutment  9  in a loss-proof manner by means of different connecting means. One conceivable example is to connect the legs  5  of the clamping yoke  4  to the abutment  9  by means of a hinge on one side of the axle housing and to connect the remaining, free legs  5  to the free end of the abutment  9  by means of a screw coupling or some other connection device. 
       FIG. 5  shows the axle housing  2  in side view with the attachment device according to the invention in the installed condition  40 . The attachment device has a clamping yoke  4  and an abutment  9  connected to the clamping yoke  4 . From the side view, it is possible to see the leg  5  of the clamping yoke  4 , which rests by the contact surface  18  thereof on the fixing projection  8 . At the same time, the clamping yoke  4  is aligned on the centering device  21  of the fixing projection  8  by means of the studs  33 . Opposite the spine  10  of the axle housing  2  there is to be seen the abutment  9 , the lateral walls  19  of which carry studs  35 , by means of which the abutment  9  is centered on the fixing projection  8 . Here, the abutment  9  rests by the contact surfaces  34  thereof against the centering device  25  of the axle housing  2 , the centering device facing away from the spine  10  of the axle housing  2 . 
       FIG. 6  shows, in an overall perspective view the attachment device according to the invention for a spring element  1  on an axle housing  2  of a commercial vehicle axle  3 . Here, the clamping yoke  4  and the abutment  9  are arranged ready for use on the axle housing  2 . Resting on the upper side of the web  6  is a leaf spring pack  36 , which is positioned on the web  6  by means of clamps  37 , which are secured on the abutment  9 .  FIG. 6  illustrates that the clamping yoke  4  is seated by way of the underside  13  of the legs  5  thereof on the support surfaces  30  of the fixing projections  8 . In a manner comparable with the previous figures, the clamping yoke  4  is aligned on the axle housing by means of the centering device  21 . In a manner likewise comparable with the previous figures, the abutment  9  shown in  FIG. 6  is arranged in an accurately positioned manner by the base  20  thereof on the centering device  25  of the axle housing  2 . In  FIG. 6 , the axle housing  2  extends transversely to the driving direction  29 . The spring element  1  in the form of a leaf spring pack  36  extends approximately at right angles to the axle housing  2  in the driving direction  29 . Owing to the positioning of the clamping yoke  4  on the support surfaces  30  of the fixing projections  8 , the legs  5  of the clamping yoke  4  rise above the axle housing  2  of the commercial vehicle axle  3 , with the result that the web  6  of the axle housing  2  is disposed at a spacing distance  38  from the spine  10  of the axle housing  2 . 
       FIG. 7  shows a section in the driving direction  29  through the axle housing  2  of the commercial vehicle axle  3  in the region of the means according to the invention for attaching the spring element  1  (not shown). The vehicle axle  3  extends within the axle housing  2 . The fixing projections  8  are shown in the region of the neutral axis  11  of the axle housing  2 . The fixing projections  8  project on both sides from the axle housing  2  of the commercial vehicle axle  3  in the driving direction  29 , at the level of the neutral axis  11  of the axle housing  2 . The profile illustration  14  of the fixing projections  8  shows the support surfaces  30  of the fixing projections  8  and the centering device  21 . The legs  5  of the clamping yoke  4  rest on the support surfaces  30  of the fixing projections  8  by the respective underside  13  of the leg. To center the legs  5  of the clamping yoke  4  relative to the centering device  21  of the fixing projection  8 , the studs  33  of the legs  5  are provided. Formed on the side of the axle housing  2  remote from the spine  10  of the axle housing  2  is the abutment  9 , which rests by the contact surfaces  34  thereof on the base  20  against the axle housing  2 . Here, the centering devices  25  are used for the accurately positioned alignment of the abutment  9  relative to the axle housing  2 . In  FIG. 7 , the clamping yoke  4  with the legs  5  thereof is shown above the spine  10  of the axle housing  2 . A hole  39 , which extends in the driving direction  29 , is provided in the legs  5  of the clamping yoke  4  in order to reduce the weight. According to the invention, the web  6  of the clamping yoke  4  is at a distance  38  from the spine  10  of the axle housing  2  in the installed condition  40 . It is apparent from this that the introduction of force  41  by the spring element  1  (not shown) via the locating device  32  of the web  6  does not take place directly and vertically into the spine  10  of the axle housing  2  but into the fixing projections  8  of the axle housing  2  via the legs  5  of the clamping yoke  4  in the region of the neutral axis  11 . The distance  38  between the web  6  of the clamping yoke  4  and the spine  10  of the axle housing  2  is visible in  FIG. 7 . 
       FIG. 8  shows a portion of a longitudinal section, transversely to the driving direction  29  through the axle housing  2 , in which the attachment device according to the invention for the spring element  1  (not shown) is shown in the installed condition  40 .  FIG. 8  shows the abutment  9  on the side of the commercial vehicle axle  3  facing away from the spine  10  of the axle housing  2 , and also shows the web  6  of the clamping yoke  4  with the distance  38  thereof from the spine  10  of the axle housing  2 .