Patent Application
20070001522
The present invention relates to an elastic, vibration-damping mounting of an assembly with respect to a holding device that is fixed in the frame, having at least one elastic element.
Elastic, vibration-damping mountings according to the definition of the species are known. Such a vibration-damping mounting is especially intended to dampen torsional vibrations. To do this, at least one elastic element is situated between a component of the assembly and a component of the mounting that is fixed to the frame. The elastic element is made of a yielding material, preferably an elastomer. Because of forces such as the ones that occur in vibrations, the elastic element is deformed mechanically, for instance, pressed together, and therewith takes up the energy of the vibration. Because of its restoring behavior, the elastic element takes up once more its original shape and size. This process will repeat, so that a part of the energy of the vibration is consumed, and the vibration is damped. Thus, the damping takes place based on the pressing together of the elastic element between the components of the assembly and the mounting that is fixed to the frame, in many cases the damping of the vibration not being sufficient.
By contrast, the elastic vibration-damping mounting according to the present invention offers the advantage that, on the elastic element, a free bridge is formed by the positioning of the support surfaces on components of the assembly and the mounting fixed to the frame in a laterally offset position. In the related art, the elastic element is only pressed together by clamping, and is not able to expand beyond the boundaries of its original size. In the present invention, however, a free bridge is developed, which permits a shearing motion of the elastic element, transversely to the direction of the vibration. By a shearing motion we mean, in this instance, the superposition of a torsional motion and a bending motion, and not a shearing movement having the effect of shearing off material. This shearing motion results in the extension of the elastic element, also transversely to the direction of the vibration. Depending on the extent of the deflection, an extreme extension is possible, for example, while forming an S-shaped form of the free bridge, since there is enough space available. This space is present based on the “freedom” of the free bridge, that is, since it is not clamped in between components. When unloaded, the elastic element once more takes up its initial size, based on the restoring force. The magnitude of the restoring force comes about due to the elastic properties of the material of the elastic elements. Upon being unloaded, the elastic element contracts in the opposite direction to that in which it extended before. There is created a relatively large freedom of motion for the elastic element, which leads to corresponding movements of same. Compared to the related art, by the creation of a new possibility of motion in a direction transverse to the vibrational direction, namely, permitting the shearing movement of the elastic element, a very good damping is achieved. From this, there arises the advantage that the changes in length and volume changes that are achieved, which the elastic element goes through during the squeezing together and the extension in the present invention, is of a different kind than that in the related art. In the related art, only a pressing together of the elastic element is permitted, having short changes in length, conditioned by the distance apart of the support forces of the components. Consequently, the present invention achieves a softer, more effective damping. Independently of the embodiment of the damping mechanism and the clamping device per se, the structural embodiment of the mounting that is fixed to the frame, especially the space required in the motor vehicle for accommodating the assembly in the mounting that is fixed to the frame, is similar to the type of construction described in the related art. This is relevant, since the mounting that is fixed to the frame, for example, a blower flange in a motor vehicle, is not able to be made larger at will. Because of the boundary conditions on the space available in a limited way for the mounting that is fixed to the frame, up until the present, not many design attempts were able to be implemented for the improved damping of the accommodation of an assembly in a mounting fixed in the frame.
In a preferred embodiment of the present invention, the assembly has at least one additional third support surface that is situated at a lateral distance from the first support surface, as well as a lateral distance from the second support surface. This third support surface faces the second support surface, and runs transversely, particularly at right angles, to the plane of vibration. As seen in the direction of the plane of vibration of the vibration, the second support surface lies between the first and the third support surface. As seen in the direction of vibration, the first elastic element lies in an overlapping position with respect to the second support surface and the third support surface, and it bridges the lateral distance between the second support surface and the third support surface in the form of a second free bridge.
Compared to the arrangement described before, this has the advantage that two free bridges have been developed, and the elastic element is able to move into two free spaces. This is advantageous for the damping of the vibration.
The mounting fixed to the frame has two support surfaces, and the assembly has one support surface. The damping takes place in the same manner as that which was described in the previous paragraph.
In one additional preferred embodiment, the mounting fixed to the frame has a fifth support surface that faces the second support surface. The assembly has a sixth and a seventh support surface, which have a lateral clearance from each other, and face the fifth support surface, and, as seen in the direction of the vibration plane of the vibration, the fifth support surface lying between the sixth and the seventh support surface, and a second elastic element, as seen in the direction of the vibration, lies in the overlapping position to the fifth, sixth and seventh support surfaces. The second elastic element bridges the lateral clearance between the fifth and the sixth support surface in the form of a fourth free bridge, as well as the lateral clearance between the fifth and the seventh support surface in the form of a fifth free bridge. The damping of the vibrations of the assembly takes place, in the embodiment described here, over the same vibration period, that is, a first half-wave having to and fro motion, and a second half-wave having to and fro motion. In the embodiments described before, on the other hand, only one half-wave of the vibration is damped. In the exemplary embodiment now being examined, the first half-wave is damped by the first elastic element, and the second half-wave appertaining to this is damped by the second elastic element. The first half-wave is damped in the form of a shearing movement of the first elastic element, the first and second free bridge acting along with it. In this context, the extension of the first elastic element increasing to a maximum extension. In the return motion of the first half-wave, because of the restoring force, the first elastic element contracts again until it reaches its original initial length. There it remains essentially at rest. The second half-wave of the vibration is damped by the second elastic element, which extends in the opposite direction to the first elastic element. Here too, there is again a point of maximum extension, and when this is reached, the second elastic element contracts again until it reaches its initial length. This process of extending and contracting of both elastic elements repeats several times with decreasing maximum extension in each case, until the elastic elements remain in their initial position. The vibration present as a one-time pulse is damped. If the operation of the assembly leads to continuous created vibrations, the shearing movement of the elastic elements does not die away down to zero, but leads to a continual amplitude reduction in the vibrations.
It is advantageous if the widths of the support surfaces are in each case less, compared to the lateral clearance of two support surfaces, in order to optimize the damping by the free bridge. However, the bridge should not be so small that the respective support surface cuts into the elastic element, for, if the width of the support surfaces is too small, then the surface load of the respective support surface could possibly be too great, so that the soft material of the elastic element is damaged.
In one preferred exemplary embodiment, it is provided, for the embodiment of the first and/or second elastic element, that it is made up in each case of several elastic partial elements. Alternatively it is provided that the first elastic element is developed as a unit together with the second elastic element. This unit may be made up of several Parts fastened to one another, or it may be formed as a one-piece component. A preferred exemplary embodiment of this one-piece development of the first elastic element and the second elastic element is a rectangular ring.
In one preferred exemplary embodiment, the mounting fixed to the frame has pockets that have two opposed pocket side surfaces, the two pocket side surfaces forming the two support surfaces.
In another preferred exemplary embodiment it is provided that the support surfaces of the assembly are developed in an adapter that is detachably connected to the assembly. This has the advantage that an assembly, that does not have any support surfaces, is able to be furnished with support surfaces by the simple assignment of the adapter.
In a further preferred exemplary embodiment of the present invention, it is provided that, as far as the assembly is concerned, a driving assembly is involved, especially an electric motor. This is preferably a DC motor. In still another preferred embodiment of the present invention, it is provided that the assembly is a driven assembly, for instance, a fan ventilator.
In yet another exemplary embodiment of the present invention, it is provided that the assembly is a motor vehicle assembly, and the mounting fixed to the frame is, for instance, a fixing structure of the chassis of the motor vehicle.
The subject matter of the present invention is preferably used for the damping of torsional vibrations, that is, vibrations about the axis of rotation about the shaft of the assembly developed as a motor.
Mounting 1 fixed on the frame has a predominantly pot-shaped form, having a cylindrical sidewall 2 and a bottom 3. At side wall 2, a protuberance 5 is shown, which forms a pocket 6 that is described in more detail in
In mounting 1 that is fixed to the frame, there is situated an assembly 19, in this case an electric motor 12, for instance a DC motor, having an essentially pipe-shaped stator frame 13. Electric motor 12 has a shaft 14.
Axis of rotation 15 of electric motor 12 runs through the shaft. At stator frame 13 of electric motor 12, at its circumference, holding tabs 17 are situated. Holding tabs 17 have an essentially rectangular side surface and, as a rule, are formed in one piece with stator frame 13. Furthermore, a device 20 is shown, which includes pocket 6 of mounting 1 that is fixed to the frame, holding tabs 17 and a damping element 21. Damping element 21 is developed in the shape of a bonnet, in this case, and has a first end face 22, a second end face 23 and a wall 24 that connects the latter two. Electric motor 12 is mounted in mounting 1 that is fixed to the frame, by being pushed along axis of rotation 15 into pot-shaped mounting 1 that is fixed to the frame, and, to be specific, so far until damping element 21 adjoins at its end wall 22 to pocket end face 7′ of pocket 6. Damping element 21 is fixed at second end face 23 by end 10 of projection 9, after it has engaged, because of its deformation made possible by its elastic material properties, in an opening 18 between end 10 of projection 9 and pocket 6.
In the following, the same parts are furnished with the same reference numerals, in order to avoid repetitions.
Axis of rotation 15 runs into the plane of the drawing at the center of electric motor 12, and is shown as x. At circumference 16 of electric motor 12, four devices 20 may be seen, for accommodating electric motor 12 in mounting 1 that is fixed to the frame. A device 20 is designed in such a way that, between holding tabs 17 and pocket 6 of mounting 1 that is fixed to the frame, there is a damping element 21. Depending an the constructive design of electric motor 12, two diametrically opposite or even three devices 20 are possible, they being situated essentially at equal angular distances at the circumference. Alternatively, four devices 20 may also be situated at a distance of 90° from one another, as shown in this figure, or more devices 20, having in each case essentially the same angular distance from one another, at circumference 16 of electric motor 12.
In addition, it is also possible to situate devices 20 at circumference 16 of electric motor 12 in such a way that the angular spacing of devices 20 is irregular.
For example, in the operation of electric motor 12, because of cogging torque, rotary vibrations occur, vibrational direction 26 of the rotary vibration to be damped about axis 15 being shown as a double arrow. In order to reduce the transmission of rotary vibrations from electric motor 12 to mounting 1 that is fixed to the frame, accommodation device 20 is developed so that the rotary vibrations are damped by positioning the damping elements 21 between electric motor 12 and mounting 1 that is fixed to the frame. In FIGS. 3 to 7, exemplary embodiments of device 20 are shown schematically. In the light of these exemplary embodiments, there is shown also the operating mode of the rotary vibration-damping accommodation of an electric motor 12 in a mounting 1 that is fixed to the frame, using device 20.
In
Consequently, elastic element 33 is able to move into both free spaces 36 and 42. Lateral clearance 32 between support surface 30 and support surface 31 corresponds to the length of first free bridge 34, and lateral clearance 43 between support surface 40 and support surface 31 corresponds to the length of free bridge 41. As in
In a schematic representation,
Lateral clearance 32 between support surface 30 and support surface 31 determines the length of free bridge 34, and lateral clearance 48 between support surface 30 and support surface 40 determines the length of free bridge 46. The overlapping area of elastic element 33 and with support surface 45 is designated by 35″. If a vibration in vibration plane 25 occurs in such a way that support surfaces 31 and 45 have applied to them a pulse of the rotary vibration that is directed upwards, first elastic element 33 moves with extension of its length into free spaces 37 and 47.
If the vibration occurs in the opposite direction, and support surface 30 of holding tab 17 has applied to it a pulse directed downwards, first elastic element 33 moves into free space 36.
First elastic element 33, in this context, in a moving-in motion, executes a maximum excursion and length extension, and, upon a subsequent return motion to the initial position, it executes the first half-wave of a vibration.
If holding tabs 17 are moved downwards beyond the initial position shown in
In an advantageous manner, the dimensions, in this context, are selected in such a way that the length of the free space between holding tabs 17, which is bridged by elastic elements 33 or 54, is clearly greater than the length of support surfaces 31 or 51 on which elastic elements 33 or 54 are supported on the projection of pocket side walls 8 or 8′. In this way it is possible to damp rotary vibrations brought on by the motor in a better manner, since elastic elements 33 or 54 are movable in a tangential direction, because of the corresponding free space between holding tabs 17.
Here too, the dimensions are selected in such a way that the position of the free space between holding tabs 17, that is bridged by elastic element 21, is clearly greater than the length of support surfaces 31 or 51, on which elastic element 21 is supported at the projection of pocket side wall 8 or 8′.
Holding tabs 17, which are formed as one piece with electric motor 12 in the exemplary embodiment shown in
For all the exemplary embodiments described of a rotary vibration-damping accommodation of an electric motor 12 in a mounting 1 that is fixed to a frame, it is true that the width of the support surfaces has, in each case, to be substantially smaller than the respective lateral clearance between the two support surfaces, in order to guarantee the functioning of the free bridges.
A device for accommodating an assembly 19, such as an electric motor 12 in a mounting fixed to a frame, may also gave more support surfaces than the number of support surfaces of the exemplary embodiments shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 103-44-624.9 | Sep 2003 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DE04/01694 | 7/28/2004 | WO | 3/27/2006 |
