TUBULAR ANTIVIBRATION DEVICE

A tubular antivibration device includes an inner axial member and an outer tubular member that are joined by an elastic rubber main body. The inner axial member is provided with a pair of groove-shaped recesses that open on the outer peripheral surface on both sides in the lateral direction and extend in the vertical direction, and the elastic rubber main body is integrally provided with a pair of upper and lower first elastic joining parts that join the vertically opposing surfaces of the inner axial member and the outer tubular member to each other on both sides in the vertical direction and a pair of left and right second elastic joining parts that join the vertically opposing surfaces of the outer tubular member to each other through the pair of groove-shaped recesses of the inner axial member.

TECHNICAL FIELD

The disclosure relates to a tubular antivibration device applied to, for example, an engine mount, a differential mount, etc. of an automobile.

RELATED ART

Conventionally, there is known a tubular antivibration device having a structure in which an inner axial member and an outer tubular member are joined by an elastic rubber main body, as shown in International Publication No. 2015/045041 (Patent Literature 1), for example.

In the tubular antivibration device of Patent Literature 1, the vertically opposing surfaces of the inner axial member and the outer tubular member are joined by the elastic rubber main body, and a high spring constant based on the compression spring components of the elastic rubber main body can be set in the vertical direction.

However, the spring properties required in each direction of the tubular antivibration device are not constant, and are appropriately set according to, for example, the properties required for each vehicle to which the tubular antivibration device is applied. Thus, with the structure of Patent Literature 1, one of the purposes of which is to set a high spring constant in the vertical direction, it may be difficult to cope with, for example, a case where a low spring constant is required in the vertical direction.

In the structure of Patent Literature 1, if the lateral width of the joining leg part that constitutes the elastic rubber main body is reduced, the spring constant in the vertical direction can be reduced, but consequently, buckling of the elastic rubber main body (joining leg part) is likely to occur, which may hinder the durability and load support performance of the elastic rubber main body. In addition, there is a possibility that the spring constants in the axial direction and the lateral direction may become smaller than necessary, and the required spring properties (spring ratio) may not be satisfied.

SUMMARY

The disclosure provides a tubular antivibration device having a novel structure that is capable of achieving durability or the like of the elastic rubber main body while increasing the degree of freedom in tuning the spring ratio in each direction.

Aspects for understanding the disclosure will be described hereinafter, but each aspect described below is exemplary and can be employed in combination with each other as appropriate, and multiple components described in each aspect can be recognized and employed independently where possible and can also be employed in combination with any component described in another aspect as appropriate. Accordingly, the disclosure can be implemented in various other aspects without being limited to the aspects described below.

The first aspect provides a tubular antivibration device in which an inner axial member and an outer tubular member are joined by an elastic rubber main body. The inner axial member includes a pair of groove-shaped recesses that open on an outer peripheral surface on both sides in a lateral direction and extend in a vertical direction. The elastic rubber main body integrally includes a pair of upper and lower first elastic joining parts joining vertically opposing surfaces of the inner axial member and the outer tubular member to each other on both sides in the vertical direction, and a pair of left and right second elastic joining parts joining vertically opposing surfaces of the outer tubular member to each other through the pair of groove-shaped recesses of the inner axial member.

According to the tubular antivibration device constructed according to this aspect, the part that is mainly compressed and deformed when vibration is input in the vertical direction is set as the first elastic joining part which is a part of the elastic rubber main body so that the spring constant of the elastic rubber main body in the vertical direction is reduced compared to a case where the entire elastic rubber main body is compressed and deformed. Since the second elastic joining part of the elastic rubber main body is fixed to the vertically opposing surfaces of the outer tubular member through the groove-shaped recess that extends in the vertical direction, the spring constant against vibration input in the vertical direction is made smaller than the first elastic joining part to reduce the spring in the vertical direction.

Besides the spring of the first elastic joining part, the spring of the second elastic joining part also acts effectively when vibration is input in the lateral direction and the axial direction. Thus, a relatively high spring constant can be set in the lateral direction and the axial direction where the shear spring tends to reduce the spring constant. Thus, for example, it is possible to bring the springs in the lateral direction and the axial direction close to the spring in the vertical direction, and the spring ratio can be set with a large degree of freedom.

The second elastic joining part which constitutes both side portions of the elastic rubber main body in the lateral direction extends continuously in the vertical direction through the groove-shaped recess without being divided by the inner axial member. Thus, it is possible to ensure that the free length in the left and right side portions of the elastic rubber main body is long, thereby improving the durability of the elastic rubber main body.

According to the second aspect, in the tubular antivibration device described according to the first aspect, a first hollow hole is formed to penetrate the first elastic joining part of the elastic rubber main body in an axial direction, and a first stopper protrusion is provided on the vertically opposing surfaces of the inner axial member and the outer tubular member to protrude into the first hollow hole.

According to the tubular antivibration device constructed according to this aspect, the spring properties of the elastic rubber main body can be tuned by the first hollow hole, and particularly the spring in the vertical direction can be reduced. In addition, since the contact between the first stopper protrusion and the inner axial member or the outer tubular member limits the amount of relative displacement in the vertical direction between the inner axial member and the outer tubular member, damage caused by excessive deformation of the elastic rubber main body is avoided.

According to the third aspect, in the tubular antivibration device described according to the first or second aspect, second hollow holes are formed to penetrate in the axial direction on outer sides in the lateral direction with respect to the second elastic joining parts of the elastic rubber main body.

According to the tubular antivibration device constructed according to this aspect, the spring properties of the elastic rubber main body can be tuned by the second hollow hole. Since a large free surface is ensured for the second elastic joining part exposed on the hole inner surface of the second hollow hole, the durability of the elastic rubber main body is also improved.

According to the fourth aspect, in the tubular antivibration device described according to the third aspect, second stopper protrusions are respectively provided on both sides of the inner axial member in the axial direction to protrude into the second hollow holes in the lateral direction, and the groove-shaped recess is provided axially between the second stopper protrusions on both sides in the axial direction.

According to the tubular antivibration device constructed according to this aspect, since the contact between the second stopper protrusion and the outer tubular member limits the amount of relative displacement between the inner axial member and the outer tubular member in the lateral direction and the torsional direction, damage caused by excessive deformation of the elastic rubber main body is avoided. Further, the second stopper protrusion is constituted by the side wall of the groove-shaped recess, making it possible to simplify the structure and reduce the number of parts.

According to the fifth aspect, in the tubular antivibration device described according to any one of the first to fourth aspects, the second elastic joining part has an axial length that is increased toward both outer sides in the vertical direction, and the second elastic joining part has a smallest axial length that is equal to or smaller than a groove width of the groove-shaped recess.

According to the tubular antivibration device constructed according to this aspect, when vibration is input in the vertical direction, the second elastic joining part is less likely to be compressed between the groove-shaped recess and the outer tubular member, and the compression spring component of the second elastic joining part is reduced to reduce the spring in the vertical direction.

According to the sixth aspect, in the tubular antivibration device described according to any one of the first to fifth aspects, the groove-shaped recess has an axial groove width that increases toward both outer sides in the vertical direction at both end portions of the groove-shaped recess in the vertical direction, and the elastic rubber main body including the second elastic joining part is filled inside the groove-shaped recess.

According to the tubular antivibration device constructed according to this aspect, since the restriction on the second elastic joining part due to the side wall of the groove-shaped recess is reduced at both end portions of the expanded groove-shaped recess in the vertical direction, the spring constant of the second elastic joining part in the vertical direction can be further reduced.

According to the seventh aspect, in the tubular antivibration device described according to any one of the first to fifth aspects, the second elastic joining part is arranged apart from a side wall inner surface of the groove-shaped recess on an inner side of the groove-shaped recess in a groove width direction.

According to the tubular antivibration device constructed according to this aspect, since the restriction on the second elastic joining part due to the side wall of the groove-shaped recess is reduced, the spring constant of the second elastic joining part in the vertical direction can be further reduced.

According to the disclosure, it is possible to achieve durability or the like of the elastic rubber main body while increasing the degree of freedom in tuning the spring ratio in each direction.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the disclosure will be described with reference to the drawings.

FIG.1toFIG.4show an engine mount10for an automobile as the first embodiment of a tubular antivibration device constructed according to the disclosure. The engine mount10has a structure in which an inner axial member12and an outer tubular member14are joined by an elastic rubber main body16. In the following description, as a general rule, the vertical direction refers to the vertical direction inFIG.2, and the lateral direction refers to the lateral direction inFIG.2. It should be noted that each direction defined here is a direction set for the sake of convenience, and does not necessarily match, for example, each direction of the automobile.

As shown inFIG.5, the inner axial member12has a structure in which a resin member20is fixed to the outer peripheral surface of a shaft fitting18having a thick, small-diameter, substantially tubular shape. The resin member20includes a fixing tubular part22that covers the outer peripheral surface of the shaft fitting18. The resin member20includes a pair of first stopper protrusions24protruding from the fixing tubular part22to both sides in the vertical direction. The first stopper protrusion24protrudes with a substantially rectangular cross section, is shorter than the fixing tubular part22in the axial direction of the inner axial member12, and is provided in the axial central portion of the fixing tubular part22.

The resin member20of the inner axial member12includes second stopper protrusions26. The second stopper protrusions26are provided on both sides of the fixing tubular part22in the axial direction to respectively protrude to both sides in the lateral direction, and the resin member20is provided with four second stopper protrusions26. The axially inner opposing surfaces of the second stopper protrusions26on both sides in the axial direction are inclined surfaces27that are inclined outward in the axial direction toward both outer sides in the vertical direction respectively at both end portions in the vertical direction, and the axial length decreases toward both sides from the center in the vertical direction. The axial length of the second stopper protrusion26is substantially constant in the vertically central portion outside the inclined surfaces27. The protruding tip surface of the second stopper protrusion26is a curved surface that curves in an elliptical shape in the circumferential direction of the inner axial member12, and the lateral protruding height of the second stopper protrusion26decreases toward both outer sides in the vertical direction.

In the inner axial member12, a groove-shaped recess28that opens in the lateral direction and extends in the vertical direction is formed between the second stopper protrusions26arranged to face each other in the axial direction. Since the side walls of the groove-shaped recess28are constituted by the second stopper protrusions26, at both end portions in the vertical direction where the side wall inner surfaces are constituted by the inclined surfaces27, the axial groove width increases toward both outer sides in the vertical direction. Further, the lateral groove depth of the groove-shaped recess28decreases toward both outer sides in the vertical direction. Since the pair of second stopper protrusions26are provided on both sides of the inner axial member12in the lateral direction, the groove-shaped recesses28are respectively provided on both sides of the inner axial member12in the lateral direction.

The outer tubular member14has a substantially tubular shape that is thinner and has a larger diameter than the shaft fitting18of the inner axial member12, and is a hard member made of metal or the like. The outer tubular member14has a shorter axial length than the inner axial member12.

The inner axial member12is inserted into the outer tubular member14in a state of protruding to both sides in the axial direction, and the inner axial member12and the outer tubular member14are elastically joined by the elastic rubber main body16. The elastic rubber main body16includes a first elastic joining part30arranged between the vertically opposing surfaces of the inner axial member12and the outer tubular member14, and a second elastic joining part32arranged between the vertically opposing surfaces of the outer tubular member14at a position apart from the inner axial member12.

The first elastic joining part30is fixed to the inner axial member12in the axial central portion of the fixing tubular part22that constitutes the bottom wall of the groove-shaped recess28. A pair of upper and lower first elastic joining parts30are provided to be fixed to the respective surfaces of the inner axial member12in the vertical direction. Then, both ends of the first elastic joining part30in the vertical direction are fixed to the vertically opposing surfaces of the fixing tubular part22of the inner axial member12and the outer tubular member14, and the first elastic joining part30elastically joins the inner axial member12and the outer tubular member14to each other in the vertical direction on both sides in the vertical direction. The axial length of the first elastic joining part30increases from the side of the inner axial member12toward the side of the outer tubular member14in the vertical direction.

A first hollow hole34penetrating in the axial direction is respectively formed in the laterally central portion of each first elastic joining part30. As the first hollow hole34is formed, each first elastic joining part30is substantially divided into both sides in the lateral direction across the first hollow hole34. The lateral width of the first hollow hole34is smaller than the diameter (lateral width) of the shaft fitting18in the inner axial member12, and the first hollow hole34is located on the inner side in the lateral direction with respect to both ends of the shaft fitting18in the lateral direction. The first hollow hole34may have a larger lateral width than the shaft fitting18.

The first stopper protrusions24provided on both upper and lower sides of the inner axial member12protrude into the first hollow holes34. The protruding tip of the first stopper protrusion24is separated from the inner surfaces of the first hollow hole34on the upper and lower outer sides so as to form a predetermined stopper clearance.

As shown inFIG.6andFIG.7, the second elastic joining part32is fixed to the vertically opposing inner surfaces of the outer tubular member14through the groove-shaped recess28. The second elastic joining part32extends in the vertical direction through the groove-shaped recess28so that the second elastic joining part32is provided at a position apart from the inner axial member12in a vertical projection. A pair of left and right second elastic joining parts32are provided at positions corresponding to the pair of left and right groove-shaped recesses28. The groove-shaped recess28is filled with a part of the elastic rubber main body16including the second elastic joining part32. The second elastic joining part32integrally includes a central portion36arranged within the groove-shaped recess28and outer portions38protruding outward in the vertical direction with respect to the groove-shaped recess28.

In this embodiment, the lateral width w2of the second elastic joining part32is larger than the lateral width w1of the first elastic joining part30. Thus, a low spring in the vertical direction and high springs in the axial direction and the lateral direction, which will be described later, are efficiently achieved. However, the dimension relationship and ratio of the lateral widths of the first elastic joining part30and the second elastic joining part32can be appropriately changed according to the required spring ratio or the like.

In this embodiment, a position A3of the lateral outer surface of the outer portion38of the second elastic joining part32, in other words, a laterally innermost position A3of the inner surface of a second hollow hole40is set between a position A1of the protruding tip of the second stopper protrusion26and a position A2of the bottom wall surface of the groove-shaped recess28in a direction perpendicular to the axis, which is the lateral direction ofFIG.4. In addition, similarly, a position A4of the lateral inner surface of the outer portion38of the second elastic joining part32, in other words, a laterally outermost position A4of the inner surface of the first hollow hole34is set inside the outer peripheral surface of the inner axial member12in the lateral direction beyond the position A2of the bottom wall surface of the groove-shaped recess28. It should be noted that the position A4can also be set outside the position A2in the lateral direction, and in this case, the spring can be made even lower in the vertical direction. In this way, the position A4can be arbitrarily set with respect to the position A2according to the low spring properties in the vertical direction. When the position A4is set outside the position A2in the lateral direction, for example, the first elastic joining part30is provided axially outside the groove-shaped recess28so as to connect the outer tubular member14and the second stopper protrusion26in the vertical direction.

The outer portion in the vertical direction of the elastic rubber main body16which is arranged at a position apart from the inner axial member12in an axial projection has an axial end surface that is a curved surface recessed in a concave shape outward in the axial direction. Then, the outer portion of the elastic rubber main body16has the smallest axial length in the middle of the vertical direction, and the axial length of the outer end in the vertical direction on the side of the outer tubular member14is larger than the axial length of the inner end in the vertical direction on the side of the inner axial member12. In the second elastic joining part32of the elastic rubber main body16, the outer portion38protruding outward in the vertical direction with respect to the groove-shaped recess28has an axial length that gradually increases from the portion where the axial length is the smallest toward the outer side in the vertical direction on the side of the outer tubular member14. The smallest length L of the second elastic joining part32in the axial direction is smaller than the smallest groove width W of the groove-shaped recess28. It should be noted that the axial length of the entire outer portion38can also be smaller than the smallest groove width W of the groove-shaped recess28. According to this configuration, the spring is reduced in the vertical direction. In this way, the axial length of the entire outer portion38can be arbitrarily set according to the low spring properties and durability in the vertical direction. In this case, the laterally outermost position A4(seeFIG.4) of the inner surface of the first hollow hole34can also be set outside the position A2(seeFIG.4) of the bottom wall surface of the groove-shaped recess28in the lateral direction.

Preferably, as in this embodiment, in the axial direction that is the lateral direction ofFIG.7, the axially innermost points (points shown as both ends of L inFIG.7) on both axial end surfaces that are concave curved surfaces of the second elastic joining part32are both set and positioned axially inward of the axially outer end B1of the inclined surface27of the second stopper protrusion26of the resin member20, and more preferably, set and positioned axially inward of the axially inner end B2of the inclined surface27. The first elastic joining part30may be set so that the axially innermost points on both axial end surfaces thereof are positioned axially outward from B1and B2of the second stopper protrusion26of the resin member20.

Each second elastic joining part32is formed with the second hollow hole40penetrating in the axial direction. The second hollow hole40is provided outside the inner axial member12in the lateral direction, and is provided outside the second elastic joining part32in the lateral direction. The second elastic joining part32is separated inward in the lateral direction from the outer tubular member14by the second hollow hole40in the middle in the vertical direction apart from the upper and lower ends fixed to the inner peripheral surface of the outer tubular member14. The second hollow hole40has a vertical length larger than the diameter (vertical width) of the shaft fitting18of the inner axial member12, and extends to the outer side in the vertical direction from both ends of the shaft fitting18in the vertical direction.

The pair of left and right second stopper protrusions26protrude into the pair of left and right second hollow holes40, respectively. The protruding tip of the second stopper protrusion26is separated from the inner surface on the left and right outer sides of the second hollow hole40so as to form a predetermined stopper clearance.

The inner peripheral surface of the outer tubular member14is covered with a covering rubber layer42integrally formed with the elastic rubber main body16. Further, the entire outer peripheral surface of the resin member20that constitutes the inner axial member12is covered with the elastic rubber main body16including the covering rubber layer42, etc. For example, the surfaces of the first stopper protrusion24and the second stopper protrusion26are respectively covered with a buffer rubber44integrally formed with the elastic rubber main body16.

As shown inFIG.2,FIG.6, andFIG.7, since the elastic rubber main body16of this embodiment fills the entire interior of the groove-shaped recess28, it is possible to mold with a simple structure mold (not shown) divided in the axial direction. The elastic rubber main body16of this embodiment is formed as an integrally vulcanized molded product including the inner axial member12and the outer tubular member14, and for example, a process such as bonding the outer tubular member14after molding the elastic rubber main body16is not required.

The engine mount10having such a structure exhibits hard spring properties due to compressive deformation of the elastic rubber main body16when vibration is input in the vertical direction. Here, when vibration is input to the elastic rubber main body16in the vertical direction, substantially the entire first elastic joining part30is compressed between the inner axial member12and the outer tubular member14while the second elastic joining part32arranged apart from the inner axial member12in the vertical projection is hardly compressed. In this way, the elastic rubber main body16has a limited portion compressed between the inner axial member12and the outer tubular member14, and the spring properties in the vertical direction can be made relatively soft.

Furthermore, when vibration is input in the axial direction, soft spring properties are exhibited mainly due to shear deformation of the elastic rubber main body16. The elastic rubber main body16is provided with the second elastic joining parts32on both left and right outer sides of the first elastic joining part30, and since the elastic rubber main body16has a large cross-sectional area in the portion that undergoes shear deformation due to the input of vibration in the axial direction, the spring properties in the axial direction can be made relatively hard.

Further, when vibration is input in the lateral direction, soft spring properties are exhibited mainly due to shear deformation of the elastic rubber main body16. The elastic rubber main body16is provided with the second elastic joining parts32on the left and right outer sides of the first elastic joining part30, and since the elastic rubber main body16has a large cross-sectional area in the portion that undergoes shear deformation due to the input of vibration in the lateral direction, the spring properties in the lateral direction can be made relatively hard.

In this way, the engine mount10can set a relatively small spring constant in the vertical direction where the compression spring component tends to increase the spring constant, and can set a relatively large spring constant in the axial direction and the lateral direction where the shear spring component tends to reduce the spring constant than in the vertical direction. Thus, the degree of freedom in tuning the spring in each direction is increased, and it becomes possible to set the spring in each direction more appropriately when it is required to set the spring ratio small in the vertical direction, the axial direction, and the lateral direction, for example.

In addition, while the lateral width of the first elastic joining part30is reduced to set a small spring constant in the vertical direction, the second elastic joining parts32are integrally and continuously provided on both outer sides of the first elastic joining part30in the lateral direction so as to ensure the cross-sectional area of the elastic rubber main body16. Thus, buckling of the elastic rubber main body16during input is prevented, and it is possible to achieve the load resistance and durability required for the engine mount10while achieving the desired spring properties.

The groove width of the groove inner surface of the groove-shaped recess28to which the second elastic joining part32is fixed is widened toward both sides in the vertical direction. Thus, when vibration is input in the vertical direction, the restriction on the deformation of the second elastic joining part32due to the second stopper protrusion26, which is the side wall of the groove-shaped recess28, is reduced, making it easy to achieve soft spring properties.

The spring constant in the vertical direction is reduced by forming the first hollow hole34penetrating the first elastic joining part30in the axial direction. Since the first hollow hole34is provided in the laterally central portion where the compression spring component is particularly dominant in the first elastic joining part30, the spring constant in the vertical direction can be efficiently reduced. In addition, since the elastic rubber main body16has a symmetrical structure by forming the first hollow hole34in the laterally central portion, it becomes easy to prevent strain concentration and achieve load support performance and spring properties, for example.

By forming the second hollow hole40that penetrates the second elastic joining part32, soft spring properties are achieved, which achieves, for example, a good ride comfort in the automobile. Further, by forming the second hollow holes40respectively on both sides in the lateral direction, the elastic rubber main body16has a substantially laterally symmetrical structure, which makes it easy to prevent strain concentration and achieve load support performance and spring properties, for example.

Further, both end surfaces of the elastic rubber main body16in the lateral direction are not divided into upper and lower sides by the inner axial member12and extend continuously in the vertical direction through the groove-shaped recesses28. Thus, the vertical free length tends to be shortened by the inclination of the outer tubular member14due to the tubular shape, and the free length of the elastic rubber main body16at both end portions of the elastic rubber main body16in the lateral direction can be ensured long, which improves the durability of the elastic rubber main body16.

When a large load is input in the vertical direction and causes the inner axial member12to be largely displaced relative to the outer tubular member14in the vertical direction, the first stopper protrusions24of the inner axial member12come into contact with the outer tubular member14, thereby limiting the amount of relative displacement between the inner axial member12and the outer tubular member14. Such a stopper structure in the vertical direction avoids damage caused by excessive deformation of the elastic rubber main body16and improves the durability. Since the surface of the first stopper protrusion24and the inner peripheral surface of the outer tubular member14are covered with rubber elastic bodies (covering rubber layer42, buffer rubber44), the impact sound generated when the first stopper protrusion24and the outer tubular member14come into contact with each other is reduced.

When a large load is input in the lateral direction and causes the inner axial member12to be largely displaced relative to the outer tubular member14in the lateral direction, the second stopper protrusions26of the inner axial member12come into contact with the outer tubular member14, thereby limiting the amount of relative displacement between the inner axial member12and the outer tubular member14. Further, since the second stopper protrusions26are provided on both sides of the inner axial member12in the axial direction, the amount of relative displacement between the inner axial member12and the outer tubular member14in the torsional direction (tilting direction) is also limited by the contact between the second stopper protrusions26and the outer tubular member14. Such a stopper structure in the lateral direction and the torsional direction avoids damage caused by excessive deformation of the elastic rubber main body16and improves the durability. Since the surface of the second stopper protrusion26and the inner peripheral surface of the outer tubular member14are covered with the rubber elastic bodies42and44, the impact sound generated when the second stopper protrusion26and the outer tubular member14come into contact with each other is reduced.

FIG.8toFIG.14show an engine mount50as the second embodiment of the disclosure. The engine mount50has a structure in which an inner axial member12and an outer tubular member52are elastically joined by an elastic rubber main body54. In the description of this embodiment, members and parts that are substantially the same as the first embodiment are denoted by the same reference numerals in the drawings, and the description thereof is omitted.

The outer tubular member52is a substantially tubular hard member similar to the outer tubular member14of the first embodiment, and as shown inFIG.8andFIG.10toFIG.12, windows56are respectively formed on both sides of the outer tubular member52in the lateral direction. The window56is a hole having a substantially square cross section that penetrates the outer tubular member52in the lateral direction, and is formed at a position substantially corresponding to a groove-shaped recess28of the inner axial member12.

The outer tubular member52is arranged in a state of sheathing the inner axial member12, and the inner axial member12and the outer tubular member52are elastically joined by the elastic rubber main body54. The elastic rubber main body54integrally includes a first elastic joining part30fixed to the vertically opposing surfaces of the inner axial member12and the outer tubular member52, and a second elastic joining part58fixed to the vertically opposing inner surfaces of the outer tubular member52through the groove-shaped recess28of the inner axial member12.

As shown inFIG.11andFIG.14, a central portion60, which extends within the groove-shaped recess28, of the second elastic joining part58is spaced inward in the axial direction (groove width direction of the groove-shaped recess28) from the second stopper protrusions26that constitute both side walls of the groove-shaped recess28. In other words, a vertically extending slit-shaped groove62is provided between the rubber elastic body fixed to the surface of each second stopper protrusion26and the central portion60of the second elastic joining part58. The grooves62open on the outer surface in the lateral direction on both sides of the second elastic joining part58in the axial direction and extend linearly in the vertical direction. By providing the second elastic joining part58with the grooves62, the axial width of the central portion60is reduced. The groove62of this embodiment extends to the outer side in the vertical direction with respect to the second stopper protrusion26, and is exposed at a position apart from the second stopper protrusion26outward in the vertical direction in the axial projection shown inFIG.9.

The groove62is formed by a mold (not shown) divided in the lateral direction, for example. That is, the groove62can be molded by a mold that is inserted in the lateral direction into the inner circumference of the outer tubular member52through the window56so as to separate the central portion60of the second elastic joining part58and the second stopper protrusion26(the side wall inner surface of the groove-shaped recess28). By providing the window56in the outer tubular member52in this way, even if the entire interior of the groove-shaped recess28is not filled with the elastic rubber main body54in the structure, the elastic rubber main body54can still be formed as an integrally vulcanized molded product including the inner axial member12and the outer tubular member52. The entire groove62is arranged at a position corresponding to the window56in the lateral projection shown inFIG.10, and is exposed to the outside through the window56.

According to the engine mount50of this embodiment, the central portion60of the second elastic joining part58is spaced from the side wall inner surface of the groove-shaped recess28by the groove62. Thus, the restriction on the second elastic joining part58due to the side wall (second stopper protrusion26) of the groove-shaped recess28can be reduced to achieve lower spring properties in the vertical direction.

Since the groove62extends further to both outer sides in the vertical direction with respect to the side wall of the groove-shaped recess2in this embodiment, the restriction on the central portion60of the second elastic joining part58due to the side wall of the groove-shaped recess28is further reduced, which advantageously reduces the spring in the vertical direction.

Although the embodiments of the disclosure have been described in detail above, the disclosure is not limited by the specific description. For example, the shaft fitting18that constitutes the inner axial member12is not necessarily limited to a tubular shape, and may have an elliptical tubular shape, a polygonal tubular shape, an irregular tubular shape, or the like. Moreover, the inner axial member12is not necessarily limited to a composite structure of a metal material and a resin material, and the entire inner axial member12can also be made of resin or metal.

Although it is desirable that the groove-shaped recess28of the inner axial member12is widened toward both outer sides in the vertical direction, the groove-shaped recess28may extend with a constant groove width, for example. In addition, the groove width of the groove-shaped recess28in the central portion in the vertical direction is not necessarily constant, and the groove width may vary over the entire groove-shaped recess28in the vertical direction.

The first hollow hole34is not essential. Further, the spring properties can also be adjusted by providing a first hollow recess having a bottomed concave shape which opens on the end surface in the axial direction and does not penetrate in the axial direction in place of the first hollow hole34, for example. Similarly, the second hollow hole40is not essential. Further, a second hollow recess having a bottomed concave shape can also be used in place of the second hollow hole40, for example.

The first stopper protrusion24protruding into the first hollow hole34is not essential. Further, the first stopper protrusion may be provided to protrude from the side of the outer tubular member14toward the inner axial member12.

In the above-described embodiments, the second stopper protrusion26protruding into the second hollow hole40constitutes the side wall of the groove-shaped recess28, but the second stopper protrusion may be provided separately from the side wall of the groove-shaped recess28. When the second stopper protrusion is provided separately from the side wall of the groove-shaped recess28, the second stopper protrusion may be provided to protrude from the side of the outer tubular member14toward the side of the inner axial member12. When the side wall of the groove-shaped recess28does not constitute the second stopper protrusion, the second stopper protrusion is not essential.

In the first embodiment, the entire interior of the groove-shaped recess28is filled with the elastic rubber main body16, but a part of the elastic rubber main body16having a lateral height that does not reach the entire depth direction (lateral direction) of the groove-shaped recess28, for example, may fill only the bottom side of the groove-shaped recess28that does not reach the openings on the laterally outer sides.