Coil spring isolator and corresponding coil spring assembly

Abstract

The invention relates to a coil spring isolator (2) comprising an isolator body (4) comprising an end face (6), wherein the end face (6) is configured to receive a portion of a coil spring (102), and an insert (10) accommodated in said isolator body (4). The invention further relates to a coil spring assembly (100). According to the invention, the insert (10) is elastically deformable during operation in a main working direction (A) of the coil spring isolator (2).

Description

[0001] Bremen, 19 August 2025

[0002] Our Ref.: BA 6035-02WO CHA / jga

[0003] Appiicant / Proprietor: BASF Polyurethanes GmbH serial Number: Subsequent Application

[0004] BASF Polyurethanes GmbH

[0005] ElastogranstraBe 60, 49448 Lemforde Deutschland

[0006] Coil spring isolator and corresponding coil spring assembly

[0007] The invention relates to a coil spring isolator, the coil spring isolator comprising an isolator body comprising an end face, wherein the end face is configured to receive a portion of a coil spring, and an insert accommodated in said isolator body. Coil spring isolators of the aforementioned kind are known from the prior art. From WO 2018 / 071661 A1 a reinforcing insert is known that is utilized to provide a reinforcing function to the coil spring isolator. The reinforcing insert does only have a limited specific impact on the stiffness of the coil spring isolator. This is because the inserts which are used as of today are typically rotationally symmetrical and flat. When coil spring isolators are used, it is desirable to reduce the static and dynamic stiffness of the coil spring isolator system. This leads to an improved isolation of mechanical oscillations which ultimately results in an improved NVH (Noise Vibration Harshness) behaviour. However, the known solutions show only limited impact on the stiffness behaviour. As a consequence, it was an object to the invention to provide a coil spring isolator of the initially mentioned type which overcomes the aforementioned problems as much as possible. In particular, it was an object of the invention to provide an improved coil spring isolator that comprises an improved isolation behaviour, a reduced static and dynamic stiffness of the coil spring isolator system, and an increased lifespan. BASF SE 240280

[0008] The invention attains the aforementioned object by suggesting a coil spring isolator according to claim 1 . According to the invention, the insert is elastically deformable during operation in a main working direction of the coil spring isolator. The main working direction may be the axial direction. The main working direction may correspond to a longitudinal axis of the coil spring isolator or may depart therefrom by 15 degrees. Since the insert is elastically deformable in the main working direction during operation of the coil spring isolator, the insert acts as an additional spring within the coil spring isolator system. In other words, the insert actively participates to the static and dynamic behaviour of the coil spring isolator. This is achieved by a deformation of the insert. The deformation of the insert allows an increased displacement of the coil spring isolator system between different design loads such as full jounce, 1 G, full rebound. As a result, the static and dynamic stiffness of the coil spring isolator system is reduced, which finally leads to an improved isolation behaviour. In addition, the lifespan of the coil spring isolator system is improved compared to systems without an insert. The main working direction may be the direction with the highest loads.

[0009] In this application, the expression “elastically deformable during operation” means that the insert is elastically deformed during operation with typical loads up to full jounce load I 20kN. The reinforcing inserts known from the prior art are not elastically deformed in a substantial degree during operation of the coil spring isolator.

[0010] In one embodiment, the end face is a first axial end face and wherein the isolator body comprises a second axial end face opposite from the first axial end face. The first axial end face and / or the second axial end face may extend substantially in perpendicular to a main working direction of the coil spring. The expression “substantially perpendicular” relates to an exact perpendicular relationship under 1g-load and deviations of + / - 15 degrees therefrom.

[0011] In one embodiment, the isolator body is substantially flat. The first end face and / or the second end face may comprise even surfaces.

[0012] In an alternative embodiment, the isolator body comprises an uneven surface. The uneven surface may be arranged at the first end face, the second end face or a mantle surface arranged between the end faces.

[0013] In one embodiment, the isolator body comprises a collar. The insert may be arranged at least partially in that collar. BASF SE 240280

[0014] In one embodiment, the isolator body has a rotationally symmetric shape around a longitudinal axis which may be equal to the main working direction. This design is beneficial because the isolator body can be flexibly and easily mounted.

[0015] In one embodiment, the isolator body has the form of a sickle or banana, which might be beneficial to influence damping properties and safe weight and material. In one embodiment, the isolator body may comprise a pithed basic shape.

[0016] The isolator body may have a basic shape of a circular sector when seen in the main working direction. The isolator body may extend along at least 90 degrees in a circumferential direction along the main working direction and less than 180 or 270 degrees in the circumferential direction. In one embodiment, the isolator body may extend along at least 180 degrees in a circumferential direction along the main working direction and less than 270 degrees. When the isolator body comprises a central bore along the main working direction, a banana or sickle shape may emerge.

[0017] In one embodiment, the insert comprises a circumferential surface extending in a circumferential direction around the longitudinal axis, and wherein the circumferential surface comprises a variable axial extension around the circumferential direction. By providing the circumferential surface with a variable axial extension around the circumferential direction, it can be achieved that the insert is elastically deformable in a main working direction during operation of the coil spring isolator. The term axial extension relates to an extension in the direction of the longitudinal axis.

[0018] According to one embodiment, the circumferential surface may comprise a substantially constant axial thickness. In other words, the axial component width is kept constant. The axial thickness may be determined in the direction of the longitudinal axis. Thus, the elastic deformability is not achieved by adjusting the axial thickness of the circumferential surface but the axial thickness relatively is kept constant. Rather, by varying the axial extension around the circumferential direction, the required deformability is provided.

[0019] According to one embodiment, the circumferential surface is formed as a wave extending in a circumferential direction. The wave may be formed as a sinus wave. This wave-form of the circumferential surface has been found to be beneficial to provide the required elastic deformability of the insert. BASF SE 240280

[0020] According to one embodiment, the insert comprises at least one resilient flap attached to the circumferential surface, wherein the flap is resilient in the main working direction. When the insert is compressed in the main working direction, the resilient flap is elastically deformed, thus providing the elastic deformability of the insert. The insert may comprise two or more resilient flaps, in particular eight resilient flaps, that are attached to the circumferential surface and that are spaced in the circumferential direction. Preferably, the resilient flaps are spaced uniformly around the longitudinal axis. By providing flaps that are uniformly spaced around the longitudinal axis, the insert is elastically deformed in the main working direction in a uniform way.

[0021] The insert may have the form of a plate spring. The plate spring preferably has no undercuts in the main working direction.

[0022] According to one embodiment, the at least one resilient flap comprises a cut-out. By providing a cut-out in the resilient flap, the connection between the isolator body and the flap is improved. When the isolator body is molded around the insert, the material may flow into the cut-outs thus providing a durable connection between the isolator body and the insert. The at least one resilient flap may be attached inwardly at the circumferential surface and extend outwardly therefrom in the radial direction.

[0023] In an alternative embodiment, the at least one resilient flap may be attached outwardly at the circumferential surface and extend inwardly therefrom in the radial direction. Further, the at least one resilient flap may be attached on radially oriented areas.

[0024] In one embodiment, the insert may be configured as spring cage.

[0025] According to one embodiment, the circumferential surface comprises at least one axial opening extending through the circumferential surface, in particular two or more axial openings. When the isolator body is molded around the insert, material may flow into these axial openings improving the connection between the isolator body and the insert.

[0026] In one embodiment, the isolator body is made of an elastomer, in particular a compressible microcellular polyurethane elastomer or rubber. A suitable compressible microcellular polyurethane elastomer in this regard is for example Cellasto, a trademark of BASF.

[0027] Microcellular polyurethane elastomers which, in a preferred embodiment, have a density according to DIN 53420 of 200 kg / m3 to 1 100 kg / m3, preferably 300 kg / m3 to 800 kg / m3, BASF SE 240280 a tensile strength according to DIN 53571 of 2 N / mm2, preferably 2 N / mm2 to 8 N / mm2, an elongation according to DIN 53571 of 300%, preferably 300% to 700%, and a tear strength according to DIN 53515 of preferably 8 N / mm to 25 N / mm are particularly preferred.

[0028] The elastomers are preferably microcellular elastomers on the basis of polyisocyanate polyaddition products, preferably having cells with a diameter of 0.01 mm to 0.5 mm, particularly preferably 0.01 to 0.15 mm.

[0029] Elastomers on the basis of polyisocyanate polyaddition products and the production thereof are known in general and described numerously, for example in EP A 62 835, EP A 36 994, EP A 250 969, DE A 195 48 770 and DE A 195 48 771 .

[0030] Production customarily takes place by reacting isocyanates with compounds which are reactive to isocyanates.

[0031] The elastomers on the basis of cellular polyisocyanate polyaddition products are customarily produced in a mold in which the reactive starting components are reacted with one another. Suitable molds here are generally customary molds, for example metal molds, which, on the basis of their shape, ensure the three dimensional shape according to the invention

[0032] The polyisocyanate polyaddition products can be produced according to generally known methods, for example by the following starting substances being used in a single or two stage process:

[0033] (a) isocyanate,

[0034] (b) compounds reactive to isocyanates,

[0035] (c) water and optionally

[0036] (d) catalysts,

[0037] (e) blowing agents and / or

[0038] (f) auxiliary and / or additional substances, for example polysiloxanes and / or fatty acid sulfonates.

[0039] The surface temperature of the inner wall of the mold is customarily 40°C to 95°C, preferably 50°C to 90°C. The production of the molded parts is advantageously carried out at an NCO / OH ratio of 0.85 to 1 .20, wherein the heated starting components are mixed and brought in a quantity corresponding to the desired molded part density into a heated, BASF SE 240280 preferably tightly closing molding tool. The molded parts are cured for 5 minutes to 60 minutes and then can be removed from the mold. The quantity of the reaction mixture introduced into the molding tool is customarily dimensioned in such a manner that the molded bodies obtained have the density already presented. The starting components are customarily introduced into the molding tool at a temperature of 15°C to 120°C, preferably of 30°C to 110°C. The degrees of compression for producing the molded bodies lie between 1.1 and 8, preferably between 2 and 6. The cellular polyisocyanate polyaddition products are expediently produced according to the “one shot” method with the aid of high pressure technology, low pressure technology or in particular reaction injection molding technology (RIM) in open or preferably closed molding tools. The reaction is carried out in particular by compression in a closed molding tool. The reaction injection molding technology is described, for example, by H. Piechota and H. Rohr in "Integralschaumstoffe", Carl Hanser- Verlag, Munich, Vienna 1975; D.J. Prepelka and J.L. Wharton in Journal of Cellular Plastics, March / April 1975, pages 87 to 98 and U. Knipp in Journal of Cellular Plastics, March / April 1973, pages 76-84.

[0040] According to one embodiment, the insert is made of at least one of the following materials: polymer, elastomer, metal, steel. All these materials have been found suitable to design the active insert. The materials may be chosen based on the expected loads and required static and dynamic stiffness of the coil spring isolator system.

[0041] According to one embodiment, the isolator body is molded around the insert. Thereby, a durable connection between the isolator body and the insert is achieved. In one embodiment, the isolator body comprises a lower Shore hardness than the insert. In this way, it is ensured that the insert may act as an additional spring and the static and dynamic stiffness of the coil spring isolator system is reduced, finally leading to improved isolation behaviour.

[0042] According to one embodiment, the isolator body comprises a receiving groove arranged at the first axial end face, wherein the receiving groove extends around the isolator body in the circumferential direction. The receiving groove guides the coil spring and ensures that the coil spring and the coil spring isolator are properly positioned relative to one another. The isolator body and the insert may comprise a central opening extending coaxially to the longitudinal axis and along the longitudinal axis.

[0043] The invention has been described so far with regard to the coil spring isolator. In a second aspect, the invention relates to a coil spring assembly comprising a coil spring and a coil BASF SE 240280 spring isolator receiving a portion of the coil spring. According to the second aspect, the coil spring isolator is configured according to any one of the preceding embodiments.

[0044] The coil spring assembly takes advantage of the same benefits and preferred embodiments as the coil spring isolator according to the invention and vice versa. In this regard and in order to avoid unnecessary repetition, reference is made to the above explanations.

[0045] For a more complete understanding of the invention, the invention will now be described in detail with reference to the accompanying drawings. The detailed description will illustrate and describe what is considered as a preferred embodiment of the invention. It should of course be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention may not be limited to the exact form and detail shown and described herein, nor to anything less than the whole of the invention disclosed herein and as claimed hereinafter. Further, the features described in the description, the drawings and the claims disclosing the invention may be essential for the invention considered alone or in combination. In particular, any reference signs in the claims shall not be construed as limiting the scope of the invention. The wording “comprising” does not exclude other elements or steps. The wording “a” or “an” does not exclude a plurality.

[0046] This invention will now be described with reference to the accompanying drawings which illustrate, by way of example and not by way of limitation, one of several possible embodiments of a coil spring isolator as proposed herein, and wherein:

[0047] Figs. 1 and 2 show a first embodiment of the coil spring isolator according to the invention in a perspective and partial sectional view;

[0048] Figs. 3 to 5 show an insert according to an embodiment of Figs. 1 and 2 in different views;

[0049] Figs. 6 and 7 show an alternative design of an insert according to the invention; and

[0050] Fig. 8 shows a coil spring assembly according to the invention in a perspective view.

[0051] Figures 1 and 2 show a coil spring isolator 2. The coil spring isolator 2 comprises an isolator body 4 and an insert 10. The isolator body 4 comprises a first axial end face 6 and a second BASF SE 240280 axial end face 8. The first axial end face 6 is arranged opposite from the second axial end face 8. The first axial end face 6 is configured to receive a portion of a coil spring 102 as shown in Figure 8. The insert 10 is accommodated in said isolator body 4. In particular, the isolator body 4 is molded around the insert 10. The insert 10 is elastically deformable in an main working direction A during operation of the coil spring isolator 2. This means that the insert 10 acts as an additional spring within the coil spring isolator 2. This is achieved by the deformation of the insert 10. The deformation of the insert 10 allows an increased displacement of the coil spring isolator 2 between the different design loads. As a result, the stiffness of the coil spring isolator 2 is reduced, which leads to improved isolation behaviour.

[0052] The insert 10 comprises a circumferential surface 12 which extends in a circumferential direction C around the longitudinal axis L. The circumferential surface 12 is arranged to substantially in parallel to the first axial end face 6 of the isolator body 4. As shown in particular in Figures 3 and 4, the circumferential surface 12 comprises a variable axial extension a around the circumferential direction C. Further, the circumferential surface 12 comprises a substantially constant axial thickness t in the circumferential direction C. The circumferential surface 12 is formed as a wave 18. The wave 18 extends in the circumferential direction C. The wave 18 is a sinus wave 18. The circumferential surface 12 comprises axial openings 24 that extend through the circumferential surface 12. The axial openings 24 allow the material of the coil spring isolator to flow into the axial openings so as to improve the connection between the isolator body 4 and the insert 10.

[0053] The isolator body 4 is made of an elastomer, in particular a compressible microcellular polyurethane elastomer or rubber. The insert 10 is made of polymer, elastomer, metal or steel. In particular, the isolator body 4 comprises a lower Shore hardness than the insert 10. The Shore hardness may be determined according to the standard ASTM D2240 or DIN ISO 7619. As shown in Figure 1 , the isolator body 4 comprises a receiving groove 26. The receiving groove 26 is arranged at the first axial end face 6. The receiving groove 26 extends around the isolator body 4 in the circumferential direction C. Furthermore, the isolator body 4 and the insert 10 comprise a central opening 28. The central opening 28 extends coaxially to the longitudinal axis L and along the longitudinal axis L as also shown, for example, in Figures 1 and 2.

[0054] Figures 6 and 7 show an alternative embodiment of an insert 10. The insert 10 comprises a circumferential surface 12 extending in a circumferential direction C around the longitudinal axis L. The circumferential surface 12 comprises a variable axial extension a around the circumferential direction C. The insert 10 comprises eight resilient flaps 20 | BASF SE | 240280 attached to the circumferential surface 12. The resilient flaps 20 are resilient in the main working direction A. The resilient flaps 20 are equidistantly spaced around the longitudinal axis L. The resilient flaps 20 comprise a cut-out 22. The cut-out 22 allows the material of the isolator body to flow through these resilient flaps 20 so that the connection between the isolator body 4 and the insert 10 is improved. The resilient flaps 20 are attached inwardly at the circumferential surface 12 and extend outwardly therefrom in the radial direction R.

[0055] Figure 8 shows a coil spring assembly 100. The coil spring assembly 100 comprises a coil spring 102 and two coil spring isolators 2 attached on each longitudinal end face of the coil spring 102. At least one of or both of the coil spring isolators 2 are configured according to the embodiments of Figures 1 to 7. Furthermore, between the coil spring isolator 2 and the coil spring 102, an intermediate piece 104 may be arranged.

[0056] BASF SE 240280

[0057] List of references

[0058] 2 coil spring isolator

[0059] 4 isolator body

[0060] 6 first axial end face

[0061] 8 second axial end face

[0062] 10 insert

[0063] 12 circumferential surface

[0064] 18 sinus wave

[0065] 20 resilient flap

[0066] 22 cut-out

[0067] 24 axial opening

[0068] 26 receiving groove

[0069] 28 central opening

[0070] 100 coil spring assembly

[0071] 102 coil spring

[0072] 104 intermediate piece

[0073] A main working direction (axial direction)

[0074] L longitudinal axis

[0075] C circumferential direction a axial extension in the circumferential direction t axial thickness

[0076] R radial direction

Claims

BASF SE240280Claims1 . A coil spring isolator (2) comprising: an isolator body (4) comprising an end face (6), wherein the end face (6) is configured to receive a portion of a coil spring (102), and an insert (10) accommodated in said isolator body (4), characterized in that the insert (10) is elastically deformable during operation in a main working direction (A) of the coil spring isolator (2).

2. The coil spring isolator (2) according to claim 1 , wherein the end face (6) is a first axial end face (6) and wherein the isolator body (4) comprises a second axial end face (8) opposite from the first axial end face (6), in particular wherein the first axial end face (6) and / or the second axial end face (8) extend substantially in perpendicular to the main working direction of the coil spring isolator (2).

3. The coil spring isolator (2) according to anyone of the preceding claims, wherein the insert (10) comprises a circumferential surface (12) extending in a circumferential direction (C) around a longitudinal axis (L) of the coil spring isolator (2), and wherein the circumferential surface (12) comprises a variable axial extension (a) around the circumferential direction (C).

4. The coil spring isolator (2) according to claim 3, wherein the circumferential surface (12) comprises a substantially constant axial thickness (t), in particular in the direction of the longitudinal axis (L).

5. The coil spring isolator (2) according to claim 3 or 4, wherein the circumferential surface (12) is formed as a wave (18) extending in the circumferential direction (C), in particular wherein (18) the wave (18) is a sinus wave (18).

6. The coil spring isolator (2) according to claim 3, wherein the insert (10) comprises at least one resilient flap (20) attached to the circumferential surface (12), wherein the flap (20) is resilient in the main working direction (A).

7. The coil spring isolator (2) according to claim 6,BASF SE240280wherein the insert (10) comprises two or more resilient flaps (20), and wherein the resilient flaps (20) are spaced in the circumferential direction (C), in particular uniformly around the longitudinal axis (L).

8. The coil spring isolator (2) according to claim 6 or 7, wherein the at least one resilient flap (20) comprises a cut-out (22) and / or wherein the at least one resilient flap (20) is attached inwardly at the circumferential surface (12) and extends outwardly therefrom in a radial direction (R) from the longitudinal axis (L).

9. The coil spring isolator (2) according to anyone of claims 3 to 8, wherein the circumferential surface (12) comprises at least one axial opening (24) extending through the circumferential surface (12), in particular two or more axial openings (24).

10. The coil spring isolator (2) according to anyone of the preceding claims, wherein the isolator body (4) is made of an elastomer, in particular a compressible microcellular polyurethane elastomer or rubber.11 . The coil spring isolator (2) according to anyone of the preceding claims, wherein the insert (10) is made of at least one of the following materials: polymer, elastomer, metal, steel.

12. The coil spring isolator (2) according to anyone of the preceding claims, wherein the isolator body (4) is molded around the insert (10).

13. The coil spring isolator (2) according to anyone of the preceding claims, wherein the isolator body (4) comprises a lower Shore hardness than the insert (10) or wherein the isolator body (4) comprises a higher Shore hardness than the insert (10).

14. The coil spring isolator (2) according to anyone of the preceding claims, wherein the isolator body (4) comprises a receiving groove (26) arranged at the first axial end face (6), wherein the receiving groove (26) extends around the isolator body (4) in the circumferential direction (C), and / or wherein the isolator body (4) and the insert (10) comprise a central opening (28) extending coaxially to the longitudinal axis (L) and along the longitudinal axis (L).BASF SE24028015. A coil spring assembly (100), comprising: coil spring (102), and a coil spring isolator (2) receiving a portion of the coil spring (102), wherein the coil spring isolator (2) is configured according to any one of the preceding claims.

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