The invention is based on a holding device for fixing an assembly, in particular a pump, to a motor vehicle, and an elastomer mount.
In the design and construction of assemblies, such as for example cooling circuit pumps for a motor vehicle, the dynamic loads which are expected in operation of the motor vehicle and which in particular affect components of the assembly, such as for example the circuit board or pin connections, constitute a challenge for developers in relation to robustness.
Examples here are requirements for the vibration tolerance of the assembly when mounted on an internal combustion engine. A rigid mounting of the assembly or pump on the internal combustion engine entails an undamped transfer of excitation energy to the pump, and hence leads to high vibrational loads on the pump. Normally, such excitation vibrations can be greatly damped by elastic mounts. In addition, the sound transmission from the assembly, which can lead to noise formation in the vehicle interior, constitutes a challenge for developers.
A holder device with an elastomer mount is already known in which the elastomer mount has an inner region for receiving an assembly. It is also known that the elastomer mount has a damping element for decoupling and damping, and a fixing element for attaching the elastomer mount in an installation space, in particular a motor vehicle. With such elastomer mounts, it is provided that the damping element is arranged evenly in the peripheral direction on the elastomer mount.
The invention is based on a holding device for fixing an assembly, in particular a pump, to a motor vehicle, with an elastomer mount and a fixing element for attaching the elastomer mount in an installation space, in particular a motor vehicle, wherein the elastomer mount comprises a substantially annular first holding element and a second holding element, wherein the first holding element has an inner region provided to receive the assembly, and wherein the second holding element is connected to the first holding element by means of at least one damping element, and wherein the fixing element is arranged on the second holding element. It is proposed that the damping element is arranged mainly in the region of the fixing element.
The holding device according to the invention has the advantage that a transmission of resonant frequencies and, associated therewith, an undesirable noise transmission from the assembly via the holder device to the motor vehicle interior can be minimized. As well as noise minimization, the holder device according to the invention, as a damping and decoupling element, may advantageously minimize dynamic loads such as for example shaking and vibrational loads which may occur in operation of the motor vehicle. At the same time, a holder device according to the invention may advantageously provide a captive clamping of the assembly. It is furthermore advantageous that the material usage for an elastomer mount according to the invention can be reduced and hence the component costs lowered.
In the context of the present invention, a damping element means in particular an element which has a damping property, i.e. is able because of the damping to reduce the amplitude of vibrations. In distinction from the first or second holding elements, the damping element according to the invention has a higher damping factor, wherein the damping factor is determined from the ratio of input size to output size of the transmission path of the system. According to the invention, this higher damping rate of the damping element may be provided by forming and, alternatively or additionally, by setting specific material properties.
The measures listed in the subclaims lead to advantageous refinements and improvements of the independent features.
The holding device according to the invention or an advantageous refinement is distinguished in that the cross-section of the damping element decreases as the distance from the fixing element increases. Because the damping element is arranged mainly in the region of the fixing element, advantageously a particularly high vibration-insulating and vibration-damping effect can be provided at the point at which the transmission path of resonant frequencies from the assembly to the motor vehicle is at its smallest. Due to the decreasing cross-section of the damping element, the installation space required for the elastomer mount can advantageously be reduced and the necessary material usage reduced to the benefit of costs.
According to a particularly preferred embodiment of the invention, the damping element has a crescent-shaped cross-section and is arranged between the first holding element and the second holding element. Because of the cross-section of the damping element with its tapering ends arranged symmetrically to the fixing element, the vibration damping and decoupling take place evenly in the region of the fixing element, wherein because the cross-section reduces continuously in the direction of the ends, peak stresses which occur usually at cross-section jumps can advantageously be prevented.
According to an advantageous refinement of the invention, it is provided that the first holding element surrounds at least portions of the damping element and, in addition or alternatively, surrounds the second holding element in the tangential direction. Due to the tangential overlap at the outer periphery between the first holding element and the second holding element, advantageously some of the holding force of the elastomer mount on the assembly can be provided by the first holding element. In theory, the first holding element may be divided into two portions. A first portion which is formed so as to be substantially annular and in mounted state lies against the assembly, and a second portion which in the manner of an outer strap at least partially overlaps the damping element and, alternatively or additionally, also the second holding element in the tangential direction.
The vibration-insulating and vibration-damping properties of the damping element may, according to a further refinement of the invention, be provided if the damping element has a plurality of first openings. These openings advantageously allow the damping element to reduce vibrations and provide an effective decoupling between the assembly and the installation space. According to an advantageous embodiment of the invention, it may be provided that the first openings are continuous openings which extend through the entire axial length of the elastomer mount. It is however expressly stated at this point that the invention is not restricted to such an embodiment of the first openings. Thus it is also conceivable that the openings may be formed as recesses open at the edge on one side or as inclusions. According to an advantageous refinement of the invention, it is provided that the cross-sections of the first openings decrease as the distance from the fixing element increases, wherein for comparison of the cross-sections of the first openings, evidently the respective cross-section of the opening in the same radial plane is considered. To optimize the vibration damping and vibration insulation, it may furthermore be provided that the cross-sections decrease continuously as the distance from the fixing point increases. The concept of a plurality of first openings here means in particular a number of between 5 and 50 first openings, wherein the openings are preferably dimensioned such that their diameter corresponds to around half the material thickness of the elastomer mount. Evidently however, the number and form of the first openings may be adapted to the respective peripheral conditions of the system. Thus for example, it is also conceivable that the damping element is formed as a foam or porous material, and hence because of the material structure a plurality of openings may mean a range far greater than 50 first openings.
According to an advantageous embodiment of the invention, it is provided that the first openings have a substantially round cross-section. Such round cross-sections can be produced easily, in particular by extrusion. It is however expressly pointed out here that other cross-sectional forms of the first openings are also conceivable insofar as suitable for providing a vibration-damping and vibration-insulating function. Thus for example it is conceivable that the first openings are formed so as to be trapezoid, wherein because of the geometry, webs remains between the first openings. Such webs may advantageously be configured so as to be particularly elastic, so that the damping element can advantageously minimize vibrations. Evidently, it is also conceivable that the first openings have an oval cross-section. According to a refinement of the invention, it is provided that the first openings each have a similar cross-section or mutually congruent cross-section.
In an advantageous refinement of the invention, the first openings are arranged along a theoretical semi-ellipse. Here it is provided that the respective first openings lie with their central points on this theoretical semi-ellipse.
According to a further advantageous refinement of the invention, it is furthermore provided that the elastomer mount has second openings in the region of the fixing element. By arranging the additional second openings in the region of the fixing element, advantageously the stiffness of the damping element in the vibration transmission region can be lowered. According to an advantageous embodiment, the round cross-section of these second openings also decreases as the distance from the fixing element increases. It is however expressly pointed out here that, with regard to the arrangement and configuration of first openings and second openings, many possible combinations are conceivable. Thus the second openings may also be configured so as to be rectangular or trapezoid. It is essential to the invention only that the damping element is arranged mainly in the region of the fixing element.
According to an advantageous embodiment of the invention, the second holding element has a substantially crescent-shaped cross-section, wherein the term “cross-section”, similarly to the opening cross-section of the first and second openings, may mean the cross-section extending in the radial plane. Such a crescent-shaped design of the second holding element advantageously ensures a load-adapted material usage.
A particularly simple and economic holding device may be provided in particular if the first holding element, the second holding element and the damping element are formed as one piece. Such a one-piece embodiment of the elastomer mount can advantageously be provided if the elastomer mount is produced by extrusion as a hollow body with an inner region suitable for receiving the assembly.
The elastomer mount according to the invention is, in a particularly preferred fashion, suitable for insertion in a holding device which is configured for attaching a corresponding assembly in an installation space, in particular a motor vehicle. Because of its embodiment with a substantially annular first holding element and a second holding element, wherein the first holding element has an inner region which is provided to receive the assembly, and wherein the second holding element is connected to the first holding element by means of at least one damping element, and wherein the second holding element has an interface for arrangement of the fixing element and the damping element is arranged mainly in the region of the interface, the elastomer mount according to the invention can minimize vibrations in a particularly advantageous fashion and at the same time can be produced easily and economically by means of extrusion.
Exemplary embodiments of the invention are shown in the figures and explained in more detail in the description below. The drawings show:
According to the invention, the holding device 12 comprises an elastomer mount 16 and the fixing element 18 via which the elastomer mount may be attached on the motor vehicle 14. As clearly evident from
A pump of the type discussed here usually has an impeller which rotates at a speed of around 3750 rpm. Thus the pump according to the invention has a resonant frequency which lies around 500 Hz. Transmission of the resonant frequency and hence the undesirable transmission of sound from the pump into the motor vehicle interior takes place via the assembly 10 through the elastomer mount 16 to the fixing element 18 and finally to the motor vehicle 14. The elastomer mount 16 according to the invention shown in
As clearly evident from
According to an advantageous embodiment of the invention, as shown for example in
In the embodiment of the invention shown in
As well as the first holding element 22, the elastomer mount 16 according to the invention furthermore has a second holding element 28. The second holding element 28 serves in particular for connecting the assembly 10 to the fixing element 18, and by its shape and arrangement ensures adequate stability of the holding device 12, and hence also a smaller deflection of the assembly 10 in the installation space. According to the invention, the fixing element 18 of the holding device 10 is arranged on the second holding portion 28. To this end, the second holding portion 28 has a receiving slot 30. In mounted state, the corresponding fixing element 18, which may for example be configured as a curved fixing plate, can be pushed through the corresponding receiving slot 30 and locked.
As well as the embodiment of the receiving slot 30 shown in
As clearly evident in
To clarify the depiction of the arrangement of the first holding element 22 and second holding element 28 relative to each other, two theoretical straight lines 34 and 36 are drawn in
As clearly shown from
According to the embodiment of the invention shown in
According to the invention, the damping element 40 is distinguished in that it has a lower stiffness than the first holding element 22 and second holding element 28. Because of the reduced stiffness of the damping element 40, this is able to damp vibrations and shaking loads and ensure decoupling of sound transmissions. Since the vibrations of the assembly 10 do not propagate significantly from the regions remote from the fixing element 18 through the elastomer mount 16 to the fixing element 18, according to the invention the damping element 40 is arranged mainly in the region of the fixing element 18. In this way, advantageously, costly damping material can be saved.
To provide the damping and decoupling function, in the embodiment of the invention shown in
The first openings 46 according to the invention achieve a reduction in stiffness in all spatial directions. To illustrate these spatial directions, both the radial direction R and the tangential direction T are drawn in
According to a possible embodiment of the invention, the first openings 46 have a cross-section which decreases as the distance from the fixing element 18 increases. As clearly evident from
As shown in
As further shown in
The second openings 56 in the embodiment shown in
The first openings 46 and second openings 56 according to
According to an advantageous embodiment of the invention, the elastomer mount is formed as one piece or integrally. The integral formation advantageously allows simple production by means of extrusion. Suitable materials for such an elastomer mount 16 produced by means of extrusion are in particular high-damping elastomer buffers which absorb the vibration energy and convert this into internal friction. In particular, EPDM (ethylene propylene diene monomer rubber) may advantageously be processed by means of extrusion, wherein by the addition of fillers or softeners, the properties can be adapted according to the given peripheral conditions.
Number | Date | Country | Kind |
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10 2017 222 668.4 | Dec 2017 | DE | national |