TUBULAR VIBRATION DAMPING DEVICE FOR ENGINE MOUNTS

Abstract

A tubular vibration damping device (10) for an engine mount comprising: an inner shaft member (12); an outer tubular member (14); and a plurality of rubber legs (40) extending between and connecting surfaces of the inner shaft member (12) and the outer tubular member (14) facing in a radial direction, wherein the plurality of rubber legs (40) comprises four rubber legs (40a, 40b, 40c, 40d) mutually extending.become further apart from each other in a circumferential direction as they go in an up-down direction and a left-right direction to a circumference, for the four rubber legs (40a, 40b, 40c, 40d), a difference in cross-sectional areas in each leg cross-section orthogonal to a longitudinal direction, which is a connecting direction of the inner shaft member (12) and the outer tube member (14), is 20% or less, and the four rubber legs (40a, 40b, 40c, 40d) have mutually different shapes and resonance states with respect to vibration input in the up-down direction.

Description

STATE OF THE ART1. Technical field

[0001] The present invention relates to a tubular vibration damping device for an engine mount or an engine support or an engine mount, which is used as an engine mount for vibration-dampingly connecting an electric motor to a vehicle body in an electrified vehicle such as an electric vehicle (BEV) and a hybrid vehicle. 2. Description of the state of the art

[0002] With the recent shift to vehicle electrification, the development of an engine mount that provides a vibration-damping connection between an electric motor and a vehicle body has been advanced. For example, as shown in Fig. 5 etc. of German Patent Publication No. DE102018221375, a tubular vibration damping device in which an inner shaft member and an outer tubular member are connected to each other by a plurality of rubber legs extending in the radial direction is used as an engine mount. SUMMARY

[0003] Incidentally, in an engine mount that dampens an electric motor, which has lower vibrations than a combustion engine, a deterioration of the vibration condition in the high-frequency range caused by swelling of the rubber legs can easily become a problem. In particular, as shown in Fig. As shown in Figure 5 of DE102018221375, when the engine mount has a plurality of rubber legs with substantially the same shape and size, the resonance frequencies of the plurality of rubber legs are almost the same, which may lead to a significant deterioration of the vibration condition at a certain frequency.

[0004] In DE102018221375, protruding mass protrusions are formed from the rubber legs, and the mass damping effect of the mass protrusions prevents the adverse effect on the vibration state caused by the rubber legs' oscillation. However, if the rubber legs are provided with the mass protrusions, the load is concentrated on the lower portions of the mass protrusions when the rubber legs are deformed during vibration initiation, which can easily lead to damage to the mass protrusions and rubber legs.

[0005] An object of the present invention is therefore to provide a tubular vibration damping device for an engine mount with a novel structure capable of preventing the vibration condition at a certain frequency from deteriorating significantly due to vibration and at the same time ensuring the durability of the rubber feet.

[0006] Preferred embodiments are described below for understanding the present invention. However, each preferred embodiment described below is exemplary and can be combined with each other as appropriate. Furthermore, a plurality of elements described in each preferred embodiment can be recognized and adopted as independently as possible, or they can also be combined with each element described in other preferred embodiments as appropriate. In this way, various other preferred embodiments can be realized in the present invention without being limited to those described below.

[0007] A first preferred embodiment provides a tubular vibration damping device for an engine mount, comprising: an inner shaft member; an outer tube member; and a plurality of rubber legs extending between a surface of the inner shaft member and a surface of the outer tube member, facing each other in a radial direction and connecting them together, wherein the plurality of rubber legs includes four rubber legs that mutually become farther apart from each other in a circumferential direction as they go to a circumference in an up-down direction and in a left-right direction, among the four rubber legs, a difference in cross-sectional areas in a leg cross section orthogonal to a longitudinal direction, which is a connecting direction of the inner shaft member and the outer tube member, is 20% or less, and the four rubber legs mutuallyhave mutually different shapes and the resonance states of the four rubber legs are mutually different with respect to a vibration input or input in the up-down direction.

[0008] In the tubular vibration-damping device for the engine mount constructed according to the present preferred embodiment, the difference in the cross-sectional areas of the four rubber legs in the leg cross-section is 20% or less. Thus, the shapes of the four rubber legs can be designed differently while the volumes of the four rubber legs remain similar to each other. This makes it possible to maintain the rubber volume of each rubber leg to prevent deterioration in durability, etc., while suppressing deterioration in spring characteristics at a specific frequency, for example, by making the resonance frequencies of the four rubber legs different.

[0009] A second preferred embodiment provides the tubular vibration damping device for the engine mount according to the first preferred embodiment, wherein two upper rubber legs of the four rubber legs have an equal length dimension in the connecting direction of the inner shaft member and the outer tube member, two lower rubber legs of the four rubber legs have an equal length dimension in the connecting direction of the inner shaft member and the outer tube member, and the length dimension of the two upper rubber legs in the connecting direction of the inner shaft member and the outer tube member is different from that of the two lower rubber legs.

[0010] In the tubular vibration-damping device for the engine mount constructed according to the present preferred embodiment, the lengths of the two upper rubber legs are equal, while the lengths of the two lower rubber legs are equal, and the lengths of the upper rubber legs are different from those of the lower rubber legs. This makes it possible, for example, to adjust the springs on the upper and lower sides accordingly, taking into account the distributed load of the engine unit and the load introduction during acceleration / deceleration, etc. Furthermore, the shapes of the rubber feet on the upper and lower sides can be designed differently by varying the lengths of the rubber feet on the upper and lower sides.

[0011] A third preferred embodiment provides the tubular vibration damping device for the engine mount according to the first or second preferred embodiment, wherein two upper rubber legs of the four rubber legs have a first common cross-sectional area portion with an equal cross-sectional area in the leg cross-section orthogonal to the longitudinal direction, which is the connecting direction of the inner shaft member and the outer tubular member, and two lower rubber legs of the four rubber legs have a second common cross-sectional area portion with an equal cross-sectional area in the leg cross-section.

[0012] With the tubular vibration-damping device for the engine mount constructed according to the present preferred embodiment, the shape difference between the upper rubber legs can be suppressed, and the shape difference between the lower rubber legs can be suppressed, so that the springs of the left and right rubber legs for the inner shaft member can be well balanced. Therefore, for example, unintentional vibration caused by an imbalance between the left and right springs or the like during vibration input in the up-down direction is suppressed, and adverse effects on the vibration state are prevented.

[0013] A fourth preferred embodiment provides the tubular vibration damping device for the engine mount according to any one of the first to third preferred embodiments, wherein an upper left rubber leg and a lower right rubber leg of the four rubber legs have the same shape in the cross section of the leg, an upper right rubber leg and a lower left rubber leg of the four rubber legs have the same shape in the cross section of the leg, and the shape in the cross section of the leg of the upper left rubber leg and the lower right rubber leg is different from that of the upper right rubber leg and the lower left rubber leg.

[0014] In the tubular vibration damping device for the engine mount constructed according to the present preferred embodiment, the cross-sectional shapes of the diagonally oppositely arranged rubber legs are the same, so that an unintentional relative displacement such as a swing between the inner shaft member and the outer tubular member during vibration initiation is prevented and the vibration state can be stabilized more easily.

[0015] According to the present invention, it is possible to prevent the vibration condition at a certain frequency from deteriorating significantly due to vibration, and at the same time ensure the durability of the rubber feet in the tubular vibration damping device for the engine mount. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or other objects, features and advantages of the invention will become more apparent from the following description of a practical embodiment with reference to the accompanying drawings in which like reference numerals designate like elements and in which: Fig. 1 is a front view of a tubular vibration damping device for an engine mount as a first practical embodiment of the present invention; Fig. 2 a cross-sectional view along the line 2-2 of Fig. 1 is; Fig. 3 is a cross-sectional view taken along line 3-3 of Fig. 1; Fig. 4 is a cross-sectional view taken along line 4-4 of Fig. 1; Fig. 5 is a cross-sectional view taken along line 5-5 of Fig. 1; Fig. 6 is a cross-sectional view taken along line 6-6 of Fig. 1; Fig. Figure 7 is a cross-sectional view taken along line 7-7 of Fig. 1; Fig. Figure 8 is a cross-sectional view taken along line 8-8 of Fig. 1; Fig. 9 is a cross-sectional view taken along line 9-9 of Fig. 1; Fig. 10 is a cross-sectional view taken along line 10-10 of Fig. 1; and Fig. Figure 11 is a diagram showing the vibration damping properties of the tubular vibration damping device for the Fig. 1 shows the engine mount. DETAILED DESCRIPTION

[0017] A practical embodiment of the present invention will be described with reference to the drawings.

[0018] Fig. 1 and Fig. 2 shows a tubular vibration damping device 10 for an engine mount (hereinafter referred to as "tubular vibration damping device 10") as a first practical embodiment of the present invention. The tubular vibration damping device 10 has a structure in which an inner shaft member 12 and an outer tube member 14 are connected in the radial direction by an elastic main body 16 made of rubber. In the following description, the top-to-bottom direction generally means the top-to-bottom direction in Fig. 1, the direction from left to right the direction from left to right in Fig. 1 and the direction from front to back the direction from left to right in Fig. 2.

[0019] As in Fig. 1, the inner shaft member 12 has a generally octagonal cross-sectional shape and extends linearly in the front-to-back direction with an approximately constant cross-sectional shape, as shown in Fig. 2. The inner shaft member 12 has a flat, transverse cross-sectional shape extending in the left-right direction, with the top-to-bottom width dimension being smaller than the left-to-right width dimension. The inner shaft member 12 has a circular bolt insertion hole 18 extending through its central portion in the front-to-rear direction. The inner shaft member 12 is made of, for example, a metal such as iron or an aluminum alloy, or a fiber-reinforced synthetic resin.

[0020] The outer peripheral surface of the inner shaft member 12, which has the shape of an octagonal prism, has an upper surface 20 and a lower surface 22 extending in a direction substantially orthogonal to the up-down direction, a left surface 24 and a right surface 26 extending in a direction substantially orthogonal to the left-right direction, an upper left inclined surface 28 connecting the upper surface 20 and the left surface 24, an upper right inclined surface 30 connecting the upper surface 20 and the right surface 26, a lower left inclined surface 32 connecting the lower surface 22 and the left surface 24, and a lower right inclined surface 34 connecting the lower surface 22 and the right surface 26.

[0021] The outer tube member 14 has a substantially cylindrical shape with a thin wall and a large diameter, extending linearly in the front-to-back direction with a nearly constant circular cross-section. Like the inner shaft member 12, the outer tube member 14 is made of a metal or a fiber-reinforced resin, etc.

[0022] The inner shaft member 12 is inserted into the outer tubular member 14, and the main elastic rubber body 16 is formed between the radially opposite surfaces of the inner shaft member 12 and the outer tubular member 14. The main elastic rubber body 16 is provided integrally with a radially inner connecting portion 36 having a small-diameter tubular shape fixed to the outer peripheral surface of the inner shaft member 12, an outer peripheral connecting portion 38 having a large-diameter tubular shape fixed to the inner surface of the outer tubular member 14, and a plurality of rubber legs 40 connecting the radially inner connecting portion 36 and the outer peripheral connecting portion 38 to each other.

[0023] The plurality of rubber legs 40 includes four rubber legs 40a, 40b, 40c, 40d. The four rubber legs 40a-40d extend between the radially facing surfaces, i.e., the outer peripheral surface of the inner shaft member 12 and the inner surface of the outer tube member 14. The rubber legs extend diagonally, as if the rubber legs become further apart from each other in the circumferential direction as they move toward the periphery in the up-down and left-right directions.In other words, the two rubber legs 40a and 40b extending upward from the inner shaft member 12 separate from each other in the circumferential direction as they go to the circumference, and the two rubber legs 40c and 40d extending downward separate from each other in the circumferential direction as they go to the circumference, with the two rubber legs 40a and 40c extending to the left and separating from each other in the circumferential direction toward the circumference, and the two rubber legs 40b and 40d extending to the right and separating from each other in the circumferential direction toward the circumference. The two rubber legs 40a and 40d are generally arranged opposite each other as they extend from the inner shaft member 12 to the upper left side and the lower right side, and the two rubber legs 40b and 40c are generally arranged opposite each other as they extend from the inner shaft member 12 to the upper right side and the lower left side.

[0024] Specifically, the rubber leg 40a extends diagonally to the upper left side of the inner shaft member 12 and inclines to the left as it moves upward, the rubber leg 40b extends diagonally to the upper right side of the inner shaft member 12 and inclines to the right as it moves upward, the rubber leg 40c extends diagonally to the lower left side of the inner shaft member 12 and inclines to the left as it moves downward, and the rubber leg 40d extends diagonally to the lower right side of the inner shaft member 12 and inclines to the right as it moves downward. Between the four rubber legs 40a-40d, holes 42 are provided in the circumferential direction and penetrate in the axial direction.The axial end surface of each rubber leg 40 is concave in longitudinal section, with the radially inner portion being inclined inward in the axial direction in the circumferential direction (toward the outer tubular member 14) and the outer circumferential portion being inclined outward in the circumferential direction (see . Fig. 4, Fig. 6, Fig. 8 and Fig. 10).

[0025] The rubber leg 40a has an axial thickness dimension Ta which is greater than the circumferential width dimension Wa in the cross section of the leg in Fig. 3, and it has an approximately rectangular shape with a large flattening in the cross-section of the leg in Fig. 3. The rubber leg 40b has an axial thickness Tb which is substantially equal to the circumferential width Wb in the cross section of the leg in Fig. 5, and is in the cross-section of the leg in Fig. 5 is generally square. The rubber leg 40c has an axial thickness Tc which substantially corresponds to the circumferential width Wc in the cross section of the leg in Fig. 7, and is in the cross-section of the leg in Fig. 7 is generally square. The rubber leg 40d has an axial thickness Td which is greater than the circumferential width Wd in the leg cross-section of Fig. 9, and has an approximately rectangular shape with a large flattening in the leg cross-section of Fig. 9. The leg cross-section is a cross-section orthogonal to the extension direction (the longitudinal direction) of the rubber leg 40 and is the cross-section orthogonal to the elastic main axis in the extension direction. However, in this practical embodiment, it is a cross-section approximately orthogonal to the radial line emanating from the center axis of the inner shaft element 12. The leg cross-sections of all rubber legs 40 in the Fig. 3, Fig. 5, Fig. 7 and Fig. 9 are leg cross-sections at almost equal distances from the center axis of the inner shaft element 12. As in the Fig. 3, Fig. 5, Fig. 7 and Fig. As shown in Figure 9, the rubber leg 40 of this practical embodiment has an axial end surface that slopes inward in the axial direction as it moves inward in the left-right direction, that is, in the circumferential direction, so that the axial thickness dimension varies in the circumferential direction. For example, the thickness at a specific location in the circumferential direction or the average value of the thickness in the circumferential direction, etc., can be assumed as the thickness dimension.

[0026] As in the Fig. 3 and Fig. 9, the cross-sectional shape of the upper left rubber leg 40a and the lower right rubber leg 40d are almost identical. As shown in the Fig. 5 and Fig. 7, the cross-sections of the upper right rubber leg 40b and the lower left rubber leg 40c are also almost identical. The cross-sectional shapes of the rubber legs 40a and 40d differ from those of the rubber legs 40b and 40c. In this practical embodiment, the ratio of the axial thickness dimension to the circumferential width dimension for the upper left rubber leg 40a and the lower right rubber leg 40d is larger than that for the upper right rubber leg 40b and the lower left rubber leg 40c.

[0027] The cross-sectional shapes of the rubber legs 40 are considered equal not only when they are exactly the same, but also when they have a similar shape with high shape conformity. In the cross-section of the legs, the rubber leg 40a has a high shape conformity to the rubber leg 40d and a low shape conformity to the rubber legs 40b and 40c. Thus, the rubber leg 40a has the same cross-sectional shape as the rubber leg 40d and a different cross-sectional shape than the rubber legs 40b and 40c. Furthermore, in the cross-section of the leg, the rubber leg 40b has a high shape conformity to the rubber leg 40c and a low shape conformity to the rubber legs 40a and 40d. Thus, the rubber leg 40b has the same leg cross-sectional shape as the rubber leg 40c and a different leg cross-sectional shape than the rubber legs 40a and 40d.

[0028] The upper left rubber leg 40a and the lower right rubber leg 40d, which have larger axial thickness dimensions, have a larger inclination angle of the axial end surface of the radially inner portion in the longitudinal cross section than the upper right rubber leg 40b and the lower left rubber leg 40c, which have smaller axial thickness dimensions. Therefore, the difference between the axial thickness dimension of the upper left rubber leg 40a and the lower right rubber leg 40d and the axial thickness dimension of the upper right rubber leg 40b and the lower left rubber leg 40c becomes larger toward the circumference.

[0029] The length dimension La of the upper left rubber leg 40a and the length dimension Lb of the upper right rubber leg 40b are almost identical to each other. The length dimension Lc of the lower left rubber leg 40c and the length dimension Ld of the lower right rubber leg 40d are also almost identical. Furthermore, the length dimension La of the upper left rubber leg 40a and the length dimension Lb of the upper right rubber leg 40b differ from the length dimension Lc of the lower left rubber leg 40c and the length dimension Ld of the lower right rubber leg 40d. In this practical embodiment, the length dimension La of the upper left rubber leg 40a and the length dimension Lb of the upper right rubber leg 40b are shorter than the length dimension Lc of the lower left rubber leg 40c and the length dimension Ld of the lower right rubber leg 40d. As a result, the center axis of the inner shaft element 12 is shifted upwards relative to the center axis of the outer tube element 14.The length of the rubber leg 40 means the length in the extension direction of the rubber leg 40, ie the direction in which the rubber leg 40 connects the inner shaft element 12 and the outer tube element 14.

[0030] As described above, the four rubber legs 40a-40d differ from each other in at least one of their cross-sectional shapes and lengths and have different shapes. Thus, depending on their different shapes, the four rubber legs 40a-40d can exhibit mutually different spring properties, for example, against vibration input in the up-down direction.

[0031] For the four rubber legs 40a-40d, the difference in the cross-sectional areas of the legs is 20% or less, e.g., in the range of 10-20%. In this practical embodiment, for the four rubber legs 40a-40d, the difference in the minimum cross-sectional areas of the legs is 20% or less, e.g., in the range of 10-20%. As a result, the four rubber legs 40a-40d do not differ significantly from one another in terms of mass.

[0032] The rubber legs 40a, 40b, which extend upward from the inner shaft element 12, have a first common cross-sectional area portion with the same cross-sectional area in the leg cross-section. The rubber legs 40c, 40d, which extend downward from the inner shaft element 12, also have a second common cross-sectional area portion with the same cross-sectional area in the leg cross-section. The first common cross-sectional area portion and the second common cross-sectional area portion can be attached at any location in the extension direction of each rubber leg 40. However, it is desirable, for example, toat a central position in the extending direction of each rubber leg 40, at a certain distance from the inner shaft member 12 or the outer tube member 14 in each rubber leg 40, or at a certain position in the extending direction of each rubber leg 40 to simplify the construction, and the like.

[0033] In this practical embodiment, the difference between the length dimensions La and Lb of the upper left rubber leg 40a and the upper right rubber leg 40b and the length dimensions Lc and Ld of the lower left rubber leg 40c and the lower right rubber leg 40d is 20% or less, preferably 15% or less. This further reduces the mass difference between the four rubber legs 40a-40d.

[0034] The four rubber legs 40a-40d have different shapes, and the difference in the minimum cross-sectional areas of the legs is 20% or less, so their resonance states differ with respect to the vibration input in the up-down direction. For example, the four rubber legs 40a-40d have different resonance frequencies for the vibration input in the up-down direction. In other words, the four rubber legs 40a-40d have different resonance states, so they do not vibrate at the same frequency at the same time.

[0035] Specifically, in this practical embodiment, the two upper rubber legs 40a, 40b have the first common cross-sectional area fraction of the same cross-sectional area, thereby reducing the volume difference between these rubber legs 40a, 40b. Similarly, the two lower rubber legs 40c, 40d have the second common cross-sectional area fraction of the same cross-sectional area, thereby reducing the volume difference between these rubber legs 40c, 40d. In this way, the volume difference or mass percentage between the two upper rubber legs 40a and 40b is further reduced, making it easier to adjust the resonant frequencies of these rubber legs 40a and 40b differently by varying the cross-sectional shape and length of these rubber legs 40a and 40b.Similarly, it is easy to adjust the resonance frequencies of the two lower rubber legs 40c and 40d so that they differ from each other in their cross-sectional shape and length.

[0036] In this way, the resonance frequencies of the four rubber legs 40a-40d are differentiated, so that in a vehicle-mounted state in which the inner shaft member 12 is fixed to the electric motor (not shown) and the outer tube member 14 is fixed to the vehicle body (not shown), when vibration is input between the inner shaft member 12 and the outer tube member 14 in the up-down direction, deterioration of the resonance state due to the resonance of the rubber legs 40a-40d is reduced.

[0037] The length dimensions La, Lb of the two upper rubber legs 40a, 40b are the same, while the length dimensions Lc, Ld of the two lower rubber legs 40c, 40d are the same, and the length dimensions La, Lb of the two upper rubber legs 40a, 40b are different from the length dimensions Lc, Ld of the two lower rubber legs 40c, 40d. This eliminates the need for the sections of the rubber legs 40 in the inner shaft member 12 and the outer tube member 14 to have a complicated shape, and the structure is simplified. Furthermore, this prevents stress concentration, which is likely to occur, on a specific rubber leg 40 during vibration transmission in the up-down direction, thereby improving, for example, the durability of the rubber legs 40.In particular, because the length dimensions Lc, Ld of the lower rubber legs 40c, 40d are longer than the length dimensions La, Lb of the upper rubber legs 40a, 40b, a longer durability and a lower resilience against an input load that displaces the inner shaft element 12 downwards relative to the outer tubular element 14 are advantageously achieved.

[0038] The rubber legs 40a, 40d have almost the same leg cross-sectional shape, as do the rubber legs 40b, 40c, and the rubber legs 40a, 40d have a different leg cross-sectional shape than the rubber legs 40b, 40c. Thus, the rubber legs 40a, 40d on both sides of the inner shaft member 12 in a diagonal direction have almost the same leg cross-sectional shape, and the rubber legs 40b, 40c on both sides of the inner shaft member 12 in a different diagonal direction have almost the same leg cross-sectional shape. This prevents unintentional relative displacement, such as swinging of the inner shaft member 12 and the outer tube member 14 during insertion in the up-down direction, and thus easily stabilizes the vibration state.

[0039] The diagram in Fig. 11, which shows the simulation results of the vibration damping properties, also shows that the tubular vibration damping device 10 of this practical embodiment achieves an excellent vibration damping effect due to the different resonance frequencies of the rubber legs 40a-40d. Fig. 11 is a graph showing the vibration damping characteristics of the tubular vibration damping device 10 of this practical embodiment against vibration in the up-down direction (example) and the vibration damping characteristics of a tubular vibration damping device of a conventional structure having four rubber legs of the same shape against vibration in the up-down direction (basic), where the horizontal axis indicates the frequency and the vertical axis indicates the dynamic spring constant.

[0040] Fig.Figure 11 shows that the example has a low peak of the dynamic spring compared to the base, which means it has excellent vibration damping performance. In other words, in the example, the four rubber legs 40a-40d resonate at different frequencies, which prevents a decrease in vibration damping performance due to the simultaneous resonance state and thus maintains the excellent vibration damping performance over a wide frequency range. On the other hand, in the base, a sudden and significant increase in the dynamic spring occurs at the frequency where some of the four rubber legs with the same shape are in a resonance state at the same time, resulting in a significant deterioration in vibration damping performance.

[0041] Thus, from the simulation results, it is clear that the tubular vibration damping device 10 of this practical embodiment has better vibration damping performance than the tubular vibration damping device of conventional type.

[0042] Although the practical embodiment of the present invention has been described in detail above, the present invention is not limited by this specific description. For example, a stopper rubber may be provided between adjacent rubber legs in the circumferential direction to limit the relative displacement of the inner shaft member and the outer tube member. This improves the durability of each rubber leg.

[0043] For example, the resonant frequencies of the four rubber legs can be adjusted to differ from each other either by their cross-sectional shape or by their length. In short, the four rubber legs can be the same in one leg's cross-sectional shape or length and different in the other.

[0044] The four rubber legs have a cross-sectional area difference of 20% or less in the leg cross-section. The cross-sectional area in the leg cross-section is not necessarily limited to the minimum cross-sectional area as shown in the first practical embodiment. Alternatively, it is possible to use the cross-sectional area at a specific location (a location at a specific distance from the inner shaft element in the longitudinal direction, a location at a specific distance from the outer tube element in the longitudinal direction, or the center in the longitudinal direction, etc.) or the average value of the cross-sectional area in the longitudinal direction, etc.

[0045] The inner shaft element is not limited to the octagonal cross-sectional shape as shown in the first practical embodiment, but it is possible to take various shapes, such as circular shapes including oval and ellipse, various polygons including rectangles, and other different shapes.

[0046] For example, all four rubber legs can have different cross-sectional shapes, and all can have different lengths. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] FROM 102018221375 [0002, 0003, 0004]

Claims

A tubular vibration damping device (10) for an engine mount, comprising:an inner shaft member (12);an outer tubular member (14); and a plurality of rubber legs (40) extending between a surface of the inner shaft member (12) and a surface of the outer tube member (14), facing each other in a radial direction and connecting them together, wherein the plurality of rubber legs (40) comprises four rubber legs (40a, 40b, 40c, 40d) that mutually move further away from each other in a circumferential direction as they go to an edge in an up-down direction and in a left-right direction, for the four rubber legs (40a, 40b, 40c, 40d), a difference in the cross-sectional areas respectively in a leg cross-section orthogonal to a longitudinal direction, which is a connecting direction of the inner shaft member (12) and the outer tube member (14), is 20% or less, and the four rubber legs (40a, 40b, 40c,40d) have mutually different shapes and the resonance states of the four rubber legs (40a, 40b, 40c, 40d) are mutually different with respect to a vibration input in the up-down direction., The tubular vibration damping device (10) for the engine mount according to claim 1, wherein two upper rubber legs (40a, 40b) of the four rubber legs (40a, 40b, 40c, 40d) have an equal length dimension in the connecting direction of the inner shaft member (12) and the outer tube member (14), two lower rubber legs (40c, 40d) of the four rubber legs (40a, 40b, 40c, 40d) have an equal length dimension in the connecting direction of the inner shaft member (12) and the outer tube member (14), and the length dimension of the two upper rubber legs (40a, 40b) in the connecting direction of the inner shaft member (12) and the outer tube member (14) is different from that of the two lower rubber legs (40c, 40d). The tubular vibration damping device (10) for the engine mount according to claim 1 or 2, wherein two upper rubber legs (40a, 40b) of the four rubber legs (40a, 40b, 40c, 40d) have a first common cross-sectional area portion with an equal cross-sectional area in the leg cross section orthogonal to the longitudinal direction, which is the connecting direction of the inner shaft member (12) and the outer tubular member (14), and two lower rubber legs (40c, 40d) of the four rubber legs (40a, 40b, 40c, 40d) have a second common cross-sectional area portion with an equal cross-sectional area in the leg cross section. The tubular vibration damping device (10) for the engine mount according to one of claims 1 to 3, wherein an upper left rubber leg (40a) and a lower right rubber leg (40d) of the four rubber legs (40a, 40b, 40c, 40d) have the same leg cross-sectional shape, an upper right rubber leg (40b) and a lower left rubber leg (40c) of the four rubber legs (40a, 40b, 40c, 40d) have the same leg cross-sectional shape, and the leg cross-sectional shape of the upper left rubber leg (40a) and the lower right rubber leg (40d) is different from that of the upper right rubber leg (40b) and the lower left rubber leg (40c).

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