JP2007245890A - Suspension bush and double joint type suspension mechanism using the same - Google Patents

Abstract

In a steering wheel of a vehicle to which a double joint type suspension mechanism is applied, generation of an excessive steering angle during low-speed turning of the vehicle can be effectively suppressed without requiring addition of special parts. The object is to provide a suspension bush having a novel structure.
An inner inclined surface and an outer inclined surface are formed at both ends in an axial direction of an inner shaft member and at both ends in an axial direction of an outer cylinder member so as to gradually decrease in diameter in the axial direction. An angle corresponding to a twist displacement angle from when the cylindrical member 14 is relatively displaced relative to the inner shaft member 12 until the outer inclined surface 22 contacts the inner inclined surface 20 via the buffer rubber layers 30 and 32: α Therefore, the inclination angle of the outer inclined surface 22 with respect to the central axis of the outer cylinder member 14 is set smaller than the inclination angle of the inner inclined surface 20 with respect to the central axis of the inner shaft member 12.
[Selection] Figure 1

Description

The present invention relates to a suspension bush for connecting a suspension arm of a vehicle to the vehicle body in a vibration-proof manner, and a double joint type suspension mechanism using the suspension bush.

  In general, a suspension mechanism for an automobile has a structure in which a carrier that rotatably supports a wheel is connected to a vehicle body by a plurality of suspension members. Conventionally, a double joint type suspension mechanism is known as a kind of such a suspension mechanism. As shown in Patent Document 1 (Japanese Patent Laid-Open No. 6-106932) and Patent Document 2 (Japanese Patent Laid-Open No. 2003-136927), this suspension mechanism is, for example, a suspension arm that connects a carrier to a vehicle body. Like the two lower arms, the structure has a pair of suspension arms that are spaced apart from each other in the vehicle front-rear direction and are separately connected to the carrier at positions separated from each other in the vehicle front-rear direction. .

  When such a double joint type suspension mechanism is adopted for a steered wheel, in general, one of a pair of suspension arms is disposed so as to extend substantially in the lateral direction of the vehicle, and the other suspension arm is a vehicle. The strut arm is disposed so as to be inclined in the front-rear direction. In addition, each of these suspension arms has one end portion connected to the vehicle body side via a suspension bush for vibration isolation, and the other end portion attached to the carrier via a ball joint or the like. Further, the suspension bush attached to the mounting portion of the suspension arm on the vehicle body side has a structure as described in Patent Document 3 (Japanese Patent Laid-Open No. 2000-88026), for example.

  That is, a suspension bush having a conventional structure generally has a structure in which an inner shaft member and an outer cylindrical member spaced apart on the outer peripheral side thereof are connected by a main rubber elastic body. The inner shaft member and the outer cylinder member are mounted in a direction perpendicular to the central axis of the suspension arm. Further, the main rubber elastic body is provided with a pair of straight portions on both sides of the inner shaft member in the direction of the central axis of the suspension arm, thereby improving riding comfort.

  However, in an automobile equipped with such a double joint suspension mechanism on the steering wheel, the wheel comes into contact with other members such as a stabilizer, especially when turning with the steering turned to the maximum at a low speed. Newly found that there is a case. As a result of checking in more detail, it was confirmed that a larger steering angle was actually generated in the wheel, exceeding the design value of the steering angle of the wheel assumed in accordance with the steering angle. is there.

JP-A-6-106932 JP 2003-136927 A JP 2000-88026 A

  Here, the present invention has been made in the background as described above, and the problem to be solved is that in a vehicle steering wheel to which a double joint type suspension mechanism is applied, an excessive amount of vehicle during low-speed turning of the vehicle is used. An object of the present invention is to provide a suspension bush having a novel structure that can effectively suppress the generation of the steering angle without requiring the addition of special parts.

In addition, the present invention provides a double-joint suspension mechanism having a novel structure that can effectively suppress the occurrence of an excessive steering angle during low-speed turning of a vehicle without requiring the addition of special parts. It is also an object to provide.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. Further, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or an invention that can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized based on thought.

  That is, the feature of the present invention is that the inner shaft member and the outer cylinder member spaced apart on the outer peripheral side thereof are connected by the main rubber elastic body, and the suspension arm in the double joint type suspension mechanism toward the vehicle body side. In the suspension bush mounted on the mounting part, inner inclined surfaces that gradually decrease in diameter as they go outward in the axial direction are formed at both axial ends of the inner shaft member, and both axial ends of the outer cylinder member On the other hand, an outer inclined surface that gradually decreases in diameter as it goes outward in the axial direction is formed, while a straight portion extending in the axial direction from both axial end portions of the main rubber elastic body is formed, and the inner portion passes through the straight portion. The inclined surface and the outer inclined surface are opposed to each other in a direction perpendicular to the axis at a predetermined distance from each other, and the inner inclined surface A shock absorbing rubber layer is formed on at least one of the surface and the outer inclined surface, and the outer cylindrical member is relatively displaced with respect to the inner shaft member so that the outer inclined surface is inclined with respect to the inner inclined surface via the shock absorbing rubber layer. The inclination angle of the outer inclined surface with respect to the central axis of the outer cylindrical member is an angle corresponding to the twist displacement angle until it is brought into contact with the surface: α, compared with the inclination angle of the inner inclined surface with respect to the central axis of the inner shaft member. The suspension bush is set small.

  In such a suspension bush having a structure according to the present invention, when a large load in the twisting direction is input between the inner shaft member and the outer cylindrical member, the inner shaft member and the outer cylindrical member are relatively twisted and displaced. Thus, the inner inclined surface of the inner shaft member and the outer inclined surface of the outer cylinder member are in contact with each other via the buffer rubber layer. Thereby, the relative displacement amount of the inner shaft member and the outer cylinder member in the twisting direction is limited in a buffering manner.

  In particular, since the inner inclined surface and the outer inclined surface are respectively provided at both axial ends of the bush, the inner shaft member and the outer cylinder member are relatively displaced in the twisting direction, so that the inner inclined surface and the outer When the inclined surface abuts, the other inner inclined surface and the outer inclined surface also abut on each other in the axial direction. Further, the direction in which both the inclined surfaces expand in a state where the inner inclined surface and the outer inclined surface are in contact with each other is inclined with respect to the axial direction of the bush including the central axis direction of the inner shaft member.

  Thus, when a large axial load is input between the inner shaft member and the outer cylindrical member with each pair of inner inclined surface and outer inclined surface being in contact with each other due to the twisting displacement, both axial directions are Based on the inclination action of the inclined surface, the axial relative displacement of the inner shaft member and the outer cylinder member is prevented.

  Therefore, even when the suspension bushing is attached to the suspension arm and a force that causes axial displacement in the state of twisting displacement is exerted, the suspension arm is reliably displaced based on the prevention of the axial displacement. Thus, it is possible to effectively prevent an excessive change (increase) in the wheel turning angle, which is considered to be caused by the displacement of the suspension arm. Therefore, in a vehicle employing a double joint type suspension mechanism, the problem of interference with other members of the wheel is advantageously solved while maintaining a good ride comfort of the vehicle and without adding special members. To get.

  In the suspension bush according to the present invention, the suspension arm constituting the double joint type suspension mechanism includes a lateral arm extending in the lateral direction of the vehicle and a strut arm extending in the longitudinal direction of the vehicle. A structure that is attached to the attachment site to the side may be employed. According to such a structure, especially in the lateral arm that handles the lateral force of the vehicle, the displacement due to the excessive change in the turning angle of the wheel is reliably suppressed, so that contact with the other members of the wheel can be prevented. This can be achieved more advantageously.

  Further, in the suspension bush according to the present invention, the main rubber elastic body has a pair of slits formed on both sides of the inner shaft member, and the straight portions formed on both sides in the axial direction by the slits are mutually connected. A connected structure may be adopted. As a result, the spring ratio in the radial direction in which the pair of slits are formed and the radial direction perpendicular thereto is set to be large. For example, while improving the riding comfort by the soft spring characteristic in the vehicle longitudinal direction, It is also possible to achieve improved handling stability due to the hard spring characteristics in the direction.

  Further, in the suspension bush according to the present invention, the sleeve-shaped stopper member is assembled to the inner shaft member in an extrapolated state, and the inner peripheral surface and the outer peripheral surface of the main rubber elastic body are the outer peripheral surface of the stopper member and the outer member. While being fixed to the inner peripheral surface of the cylindrical member, an inner inclined surface is formed by both axial ends of the stopper member, and the outer diameter dimension of the axial central portion of the stopper member is the inner inclined surface of the inner member. A structure that is smaller than the maximum outer diameter is preferably employed. According to this structure, the pair of inner inclined surfaces can be easily provided on the inner shaft member, and the production can be advantageously simplified.

  Further, by utilizing the fact that the central portion of the stopper member in the axial direction is disposed between the inner shaft member and the outer cylindrical member, a large axial load is input between the inner shaft member and the outer cylindrical member. When the inner shaft member and the outer cylinder member are in contact with each other via the axial center portion of the stopper member, the relative displacement in the direction perpendicular to the axis of the inner shaft member and the outer cylinder member is limited in a buffering manner. It is possible. In particular, since the outer diameter of the central portion of the stopper member in the axial direction is smaller than the maximum outer diameter of the inner inclined surface, the elasticity of the main body disposed between the central portion of the axial direction and the outer cylindrical member is reduced. The volume of the body is sufficiently secured, and as a result, the damping force, the durability performance, the buffer performance and the like can be further improved.

  In the suspension bush according to the present invention, the inner inclined surface of the inner shaft member is formed with a buffer surface extending in the axial direction on a flat surface or a curved surface at the inner end edge portion having the maximum outer diameter. A structure in which a stepped surface having a smaller diameter is formed further inward in the axial direction of the surface may be employed. In other words, a flat or curved buffer surface is formed at the inner edge of the inner inclined surface, so stress concentration at the inner edge is avoided, and durability and load bearing performance are further improved. Can be done. In addition, since the stepped surface having a small diameter is formed on the inner side in the axial direction of the buffer surface, the inner diameter of the buffer surface of the inner shaft member can be reduced, in other words, a pair of inner shaft members. An increase in the diameter of the central portion in the axial direction between the inner inclined surfaces is suppressed. As a result, a rubber volume disposed between the central portion in the axial direction and the outer cylinder member is suitably secured, and further improvement in damping performance and durability performance can be achieved.

  Further, the present invention is characterized by including a lateral arm extending in the vehicle lateral direction and a strut arm extending in the vehicle front-rear direction, and at least one of the lateral arm and the strut arm in the longitudinal direction. In the double joint type suspension mechanism in which the end is attached to the vehicle body side via the suspension bush and the other end in the longitudinal direction of the other of the lateral arm and the strut arm is attached to the carrier side via the ball joint. The suspension bush according to any one of the above-mentioned present invention is used, and at least one of the lateral arm and the strut arm is connected to the vehicle body side and the carrier side at the axial end portions with respect to the arm axial direction line. Center of suspension bush There as orthogonal, there suspension bushing double-joint type suspension mechanism mounted between the arm and the vehicle body.

In such a double joint type suspension mechanism having a structure according to the present invention, the suspension bushing having a specific structure according to the present invention as described above is employed, so that a good vehicle riding comfort can be ensured and an excessive amount of wheels can be obtained. A double joint type suspension mechanism that can avoid the steering angle can be advantageously realized without problems such as an increase in the number of parts and a complicated structure.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described. First, FIGS. 1 and 2 show an automobile suspension bush 10 as an embodiment of the present invention. A suspension bush (hereinafter referred to as “bush”) 10 has a structure in which an inner cylinder fitting 12 as an inner shaft member and an outer cylinder fitting 14 as an outer cylinder member are elastically connected to each other via a main rubber elastic body 16. ing.

  More specifically, the inner cylinder fitting 12 has a small-diameter thick cylindrical shape and is formed of a rigid material such as a metal material. A stopper member 18 is assembled to the inner cylinder fitting 12.

  The stopper member 18 has a substantially cylindrical shape, and is formed of a hard synthetic resin material, a metal material, or the like. The stopper member 18 is fixed to the outer peripheral surface of the inner cylindrical metal member 12 by insert molding. Further, since the axial length of the stopper member 18 is made smaller than the axial length of the inner cylinder fitting 12, both axial ends of the inner cylinder fitting 12 are protruded from both axial sides of the stopper member 18, respectively. ing. Thereby, the stopper member 18 is protruded outward from the outer peripheral surface of the inner cylindrical metal member 20 in the radial direction (axially perpendicular direction). The stopper member 18 may be externally fixed to the inner cylinder fitting 12 after being molded separately from the inner cylinder fitting 12. A more detailed structure of the stopper member 18 will be described later as an explanation of the stopper mechanism.

  On the outer peripheral side of the inner cylinder fitting 12, an outer cylinder fitting 14 is disposed on the same central axis at a predetermined distance in the radial direction. The outer cylinder fitting 14 has a large-diameter thin cylindrical shape and is formed of a rigid material such as a metal material. The axial length of the outer cylinder fitting 14 is smaller than the axial length of the inner cylinder fitting 12, and both axial ends of the inner cylinder fitting 12 protrude from both axial sides of the outer cylinder fitting 14. The stopper member 18 fixed to the inner cylinder fitting 12 and the outer cylinder fitting 14 are opposed to each other at a predetermined distance in the radial direction, and both axial ends of the stopper member 18 are the axes of the outer cylinder fitting 14. Slightly protrudes from both directions.

  A main rubber elastic body 16 is disposed between the inner cylinder fitting 12 and the outer cylinder fitting 14. The main rubber elastic body 16 has a thick, substantially cylindrical shape, and its inner peripheral surface is vulcanized and bonded to the outer peripheral surface of the inner cylindrical metal member 12 and the outer peripheral surface of the stopper member 18. Is vulcanized and bonded to the inner peripheral surface of the outer cylinder fitting 14. That is, the main rubber elastic body 16 is formed as an integrally vulcanized molded product including the inner cylinder fitting 12, the outer cylinder fitting 14, and the stopper member 18. Thus, the inner cylinder fitting 12 and the outer cylinder fitting 14 are elastically connected to each other via the main rubber elastic body 16, and the stopper member 18 is embedded in the main rubber elastic body 16.

  Here, an inner inclined surface 20 as an inner inclined surface is formed at both axial ends of the stopper member 18. The inner inclined surface 20 is formed in a region extending over a predetermined length (in the present embodiment, approximately 1/6 to 1/3 of the entire length of the stopper member 18) at the axial end portion of the stopper member 18, The stopper member 18 has a tapered shape in which the diameter dimension gradually decreases from the inner side in the axial direction toward the end. Thereby, in the longitudinal section (see FIG. 1), the inner inclined surface 20 is inclined at a predetermined angle: a with respect to the central axis: l of the inner cylinder fitting 12.

  In addition, since both the axial end portions of the outer cylindrical metal fitting 14 are subjected to reduction processing, bending processing, and the like, the axial end portions of the stopper member 18 have a diameter from the inside in the axial direction toward the end portion. A tapered outer inclined surface 22 is formed, the dimension of which gradually decreases. The axial length of the outer inclined surface 22 as the outer inclined surface is set to approximately 1/6 to 1/3 of the axial length of the outer cylindrical metal member 14. The outer inclined surface 22 is inclined at a predetermined angle: b with respect to the central axis: l of the inner cylindrical fitting 12 in the longitudinal section of the bush 10.

  A pair of inner inclined surfaces 20 and outer inclined surfaces 22 provided at both axial ends of the bush 10 are opposed to each other with a predetermined distance in the radial direction (up and down in FIG. 1). Further, the outer end portion of the inner inclined surface 20 is positioned axially outward from the outer end portion of the outer inclined surface 22, and the inner end portion of the inner inclined surface 20 is the inner side of the outer inclined surface 22. It is positioned axially outward from the end.

  The inclination angle a of the inner inclined surface 20 with respect to the central axis l of the inner cylinder fitting 12 is made smaller than the inclination angle b of the outer inclination surface 22 with respect to the central axis l of the inner cylinder fitting 12. The angle of inclination of the inner inclined surface 20: a and the angle of inclination of the outer inclined surface 22: b are not particularly limited because they are appropriately changed according to the required stopper characteristics, vehicle characteristics, etc. For example, in the present embodiment, the inclination angle a of the inner inclined surface 20 is a = 25 °, and the inclination angle b of the outer inclined surface 22 is b = 15 °, whereby the inner inclination The angle of difference between the inclination angle of the surface 20: a and the inclination angle of the outer inclined surface 22: b: a−b is set to a−b = 10 °.

  The difference between the angle of inclination of the inner inclined surface 20: a and the angle of inclination of the outer inclined surface 22: b: a−b is a result of the second lower arm 36 as a lateral arm being twisted during the steering of the automobile described later. Maximum twist angle at the time of displacement: It is the same as α (the desired twist angle that restricts the relative twist displacement of the inner and outer cylindrical fittings 12, 14) (see FIG. 3). In short, the difference between the inclination angles ab of the inner inclined surface 20 and the outer inclined surface 22 is appropriately changed in accordance with the required characteristics of the automobile.

  In addition, at the both end portions in the axial direction of the main rubber elastic body 16, the straight portions 24 are provided. The straight portion 24 is a concave longitudinal section that opens outward in the axial direction, and has a predetermined length in the circumferential direction between the inner inclined surface 20 of the inner cylindrical metal member 12 and the outer inclined surface 22 of the outer cylindrical metal member 14 (for example, In this embodiment, it extends all around. The opening portion of the straight portion 24 is positioned between the substantially radial facing surfaces of the intermediate portion in the axial direction of the inner inclined surface 20 and the outer edge portion of the outer inclined surface 22, and opens outward in the axial direction. At the same time, the bottom portion of the straight portion 24 is positioned between the substantially opposite surfaces of the inner end edge portion of the inner inclined surface 20 and the axially intermediate portion of the outer inclined surface 22. That is, the inner inclined surface 20 and the outer inclined surface 22 are opposed to each other with a predetermined distance in the radial direction via the straight portion 24. Further, since the straight portion 24 is formed, stress concentration and distortion due to tensile deformation and shear deformation of the axial end portion of the main rubber elastic body 16 are reduced.

  Particularly in the present embodiment, the buffer surface 26 is formed on the inner edge of the inner inclined surface 20. The buffer surface 26 extends in parallel with the central axis l of the inner cylinder fitting 12 by exhibiting an annular shape extending over the entire circumference with a substantially constant width dimension in the circumferential direction of the stopper member 18. The buffer surface 26 is opposed to the intermediate portion in the axial direction of the outer inclined surface 22 of the outer cylindrical metal member 14 via the straight portion 24 with a predetermined distance in the radial direction.

  Further, a stepped surface 28 is formed inward of the buffer surface 26 in the axial direction. The stepped surface 28 has a tapered shape in which the diameter gradually decreases from the inner edge of the buffer surface 26 inward in the axial direction. And the inner edge part of the step-shaped surface 28 is integrally formed with the both ends of the axial direction center part which has the cylindrical shape of the stopper member 18. As shown in FIG. In the height dimension protruding radially outward from the inner cylindrical metal fitting 12, the inner edge portion of the stepped surface 28 and the axial center portion of the stopper member 18 are the same. That is, both axial portions of the stopper member 18 including the inner inclined surface 20 and the buffer surface 26 protrude radially outward from the axial central portion of the stopper member 18, in other words, the axial direction of the stopper member 18. The central portion has a smaller diameter than both side portions in the axial direction via a pair of stepped surfaces 28 and 28. A rubber volume of the main rubber elastic body 16 is increased by fixing the main rubber elastic body 16 to the small diameter axial central portion of the stopper member 18.

  Further, the inner peripheral surface of the curled portion 24 is formed by the main rubber elastic body 16 over the entire portion, and the inner inclined surface 20, the buffer surface 26, and the outer tube of the inner cylindrical metal member 12 are disposed in the curled portion 24. The outer inclined surface 22 of the metal fitting 14 is not directly exposed. Accordingly, an inner buffer rubber 30 as a buffer rubber layer is formed on the inner inclined surface 20 and the buffer surface 26, and an outer buffer rubber 32 as a buffer rubber layer is formed on the outer inclined surface 22. It is formed. The inner buffer rubber 30 and the outer buffer rubber 32 cover the surfaces 20, 22, and 26 with substantially constant thickness dimensions, and are integrally formed with the main rubber elastic body 16.

  In the suspension bush 10 having such a structure, when a torsional load is input between the inner cylinder fitting 12 and the outer cylinder fitting 14, the inner cylinder fitting 12 and the outer cylinder fitting 14 are relatively bent. Due to the displacement, the main rubber elastic body 16 is twisted and deformed. When the twisting deformation is performed, as shown in FIG. 3, the angle between the central axis l of the inner cylinder fitting 12 and the central axis l ′ of the outer cylinder fitting 14 is the steering of the second lower arm 36. In the state where the maximum twist angle is the same as α, the inner inclined surface 20 of the inner tube metal fitting 12 and the outer inclined surface 22 of the outer tube metal fitting 14 are brought into contact with each other via the inner buffer rubber 30 and the outer buffer rubber 32. It comes to touch. As a result, the relative displacement amount in the twisting direction of the inner and outer tube fittings 12 and 14 is buffered and reliably limited by the stopper mechanism including the inner and outer inclined surfaces 20 and 22 and the inner and outer buffer rubbers 30 and 32. obtain.

  In particular, the inner inclined surface 20 and the outer inclined surface 22 formed at both ends in the axial direction of the bush 10 are inclined with respect to the central axis l of the inner cylindrical metal member 12, and the inner and outer inclined surfaces 20 and 22 and the buffer are provided. The shape and size of the surface 26, the stepped surface 28, and the inner and outer buffer rubbers 30 and 32 are the same. In short, both axial ends of the bush 10 are in a symmetrical relationship with each other. For this reason, in the twisting deformation of the bush 10, the inner inclined surface 20 and the outer inclined surface 22 positioned in one of the axial portions (for example, left in FIG. 3) on the circumferential portion in the vertical portion 24. When the inner inclined surface 20 and the outer inclined surface 20 are positioned in the other axial portion (for example, right in FIG. 3), the inner inclined surface 20, when partly contacts with each other via the inner cushion rubber 30 and the outer cushion rubber 32. The inclined surface 22 is in contact with each other via the inner shock absorbing rubber 30 and the outer shock absorbing rubber 32 at a part of the circumference within the straight portion 24. The abutting portion of the one inner inclined surface 20 and the outer inclined surface 22 in the axial direction and the abutting portion of the other inner inclined surface 20 and the outer inclined surface 22 in the axial direction are point-symmetrical positions with respect to the center point of the bush 10. It is in.

  The automobile suspension bush 10 having the above-described structure is, for example, a double wishbone type suspension that constitutes a suspension mechanism for a steered wheel (front wheel), and a pair of lower arms are connected to a hub carrier as a carrier. It is preferably used for a suspension mechanism having a double joint structure. Such a double joint type suspension mechanism has a well-known structure shown in the above-mentioned Patent Documents 1 and 2, and detailed description thereof will be omitted. However, a hub carrier provided with a king pin to which a steering wheel is attached, and a vehicle A plurality of suspension members arranged between the body and the body are included.

  Specifically, as schematically shown in FIG. 4, the lower arm includes a first lower arm 34 as a strut arm and a second lower arm 36 as a lateral arm, which are spaced apart in the vehicle front-rear direction. It consists of a pair of suspension arms, and one end of each arm 34, 36 is connected to a hub carrier (not shown) via a ball joint. Such connection positions are shown as A1 (first lower arm 34) and B1 (second lower arm 36) in FIG.

  The first lower arm 34 is arranged in front of the vehicle with respect to the second lower arm 36, and the mounting position of the second lower arm 36 with respect to the carrier in plan view: B1 is substantially the center of the wheel 38 (the center of the kingpin serving as the axle). The position of the first lower arm 34 attached to the carrier: A1 is positioned in front of the vehicle out of the center of the wheel 38. The second lower arm 36 extends substantially in the lateral direction of the vehicle (the vehicle width direction or the axle direction and the left-right direction in FIG. 4), and the first lower arm 34 is Inclined and extended at a predetermined angle with respect to the vehicle width direction. The positional relationship between the first lower arm 34 extending in the vehicle front-rear direction and the second lower arm 36 extending in the vehicle lateral direction is not particularly limited. For example, the second lower arm 36 is disposed in front of the vehicle. In addition, the first lower arm 34 may be arranged on the rear side of the vehicle.

  Furthermore, arm eyes 40 (see FIGS. 1 and 3) are formed on the other ends of the first lower arm 34 and the second lower arm 36: A2 and B2, respectively, as attachment parts to the vehicle body side. . In this embodiment, the first and second lower arms 34 and 36 may be of a curved shape or the like, but FIG. 4 simply shows the arm central axis. In the lower arms 34 and 36, the arm center axis is a straight line between the attachment position A1 (B1) to the carrier at one end in the longitudinal direction and the attachment position A2 (B2) to the vehicle body at the other end in the longitudinal direction. The connected line. The vehicle body may be a sub-frame such as a suspension frame in addition to the body body (main frame).

  Further, in the bush 10 according to the present embodiment, the outer cylinder fitting 14 is press-fitted into the arm eye 40 of the second lower arm 36, and the second lower arm 36 is positioned at a substantially axial center portion of the outer cylinder fitting 14. It is fixed in the form. In the present embodiment, the bush 10 is mounted so that the center axis of the bush 10 (the center axis of the inner and outer cylinder fittings 12 and 14) is orthogonal to the arm center axis of the second lower arm 36. Further, the bush 10 is mounted on the automobile so that the central axis thereof extends substantially in the vehicle front-rear direction. The inner cylinder 12 of the bush 10 is fixed to the vehicle body side member through a fixing bolt (not shown) inserted through the inner hole.

  As a result, the first lower arm 34 and the second lower arm 36 are independently formed between the hub carrier and the vehicle body side member based on the displacement of the ball joint and the elastic deformation of the main rubber elastic body 16 in the bush 10. The steering wheel is disposed so as to be able to swing, and the steering wheel is suspended from the vehicle body via a plurality of suspension members including the arms 34 and 36. And the 2nd lower arm 36 connected with the vehicle body side via the suspension bush 10 is extended in the vehicle horizontal direction, and will support the force of the vehicle horizontal direction of a suspension.

  In the suspension bush 10 attached to the double joint type suspension as described above, the lateral arm (second lower arm) 36 is attached to the attachment part B2 on the vehicle body side.

  That is, as shown in FIG. 4, when the steering is turned to the maximum during low speed traveling, an external force exerted on the suspension member including the second lower arm 36 as a static steering operation force by the steering operation. In addition, the cornering force that is applied to the wheel by the canvas last, the slip angle, etc. is applied.

  This cornering force is exerted from the substantially lateral direction to the axle direction with respect to the wheel 38 as indicated by arrows F1 and F2 in FIG. The cornering force acts on each suspension member including the second lower arm 36, thereby causing elastic deformation of the suspension bush including the suspension bush 10 attached to the connection portion between each suspension member and the vehicle body. . When the suspension bush is elastically deformed, the connection position of the suspension member to the vehicle body (for example, A1, A2, B1, B2 in FIG. 4) changes accordingly. As a result, especially in a double joint suspension, the displacement of the lower arms 34 and 36 causes a change in the steering angle of the wheel 38.

  In short, in a double joint type suspension, when a large cornering force is exerted by largely turning the steering wheel, the steering angle to the steering angle accompanying the displacement of the suspension member due to the elastic deformation of the suspension bush to the extent expected by static steering operation. Beyond the influence (the state indicated by the dotted line in FIG. 4), the suspension bush is greatly elastically deformed beyond that, and the displacement of the suspension member increases, so that the steering angle of the wheel is static. This is larger than the designed value (by the amounts of θ1 and θ2 in FIG. 4).

  In particular, in the inner cutting wheel (the right wheel in FIG. 4), the cornering force acts in the substantially twisting direction of the second lower arm 36. Therefore, the amount of displacement of the second lower arm 36 in the direction substantially perpendicular to the axis increases, and the steering angle increase: θ1 due to the cornering force of the wheel increases further. For this reason, there exists a possibility that a wheel may buffer to a stabilizer bar (not shown), a tire house, a suspension member, etc.

  Therefore, in the bush 10 of the present embodiment, a stopper mechanism that operates in the prying direction is employed. Thus, even when the cornering force as described above is exerted, the tilting of the second lower arm 36 in the twisting direction is reliably suppressed by the stopper action of the stopper mechanism.

  On the other hand, when the steering is greatly turned at a low speed, the second lower arm 34 is tilted by the cornering force as described above, and a load in the twisting direction is input to the bush 10, and the pair of inner inclined surfaces 20 and There is a specific form during a large turn in a low speed state in which the load in the axial direction (left and right in FIG. 3) of the bush 10 is input after the outer inclined surface 22 abuts.

  Therefore, in the contact state of the inner inclined surface 20 and the outer inclined surface 22, as shown in FIG. 3, the inclination action of each pair of the inner inclined surface 20 and the outer inclined surface 22 at both ends in the axial direction is used. The axial displacement of the bush 10 is reliably prevented. Therefore, the displacement of the second lower arm 36 parallel to the axial direction of the bush 10 in the direction perpendicular to the axis is also suppressed, and the occurrence of an excessive wheel steering angle due to the cornering force is suppressed.

  As a result, good riding comfort of the vehicle and prevention of an unexpected steering angle of the wheel can be realized at the same time, and buffering to other members caused by excessive steering angle of the wheel is achieved. Is effectively prevented.

  Further, in the present embodiment, the central portion of the stopper member 18 in the axial direction is reduced in diameter, and the volume of the main rubber elastic body 16 disposed between the inner cylinder fitting 12 and the outer cylinder fitting 14 extends over the entire circumferential direction. It is greatly secured. As a result, a sufficiently hard spring characteristic can be effectively exhibited in the lateral direction of the vehicle, and excellent steering stability can be obtained.

  The embodiment of the present invention has been described in detail above, but this is merely an example, and the present invention is not limited to a specific description in the embodiment, and is based on the knowledge of those skilled in the art. The present invention can be implemented with various changes, modifications, improvements, and the like. Further, it goes without saying that such embodiments are all included in the scope of the present invention without departing from the gist of the present invention.

  For example, the shapes of the inner inclined surface 20, the outer inclined surface 22, the inner shock absorbing rubber 30, and the outer shock absorbing rubber 32, such as shape, size, structure, arrangement position, number, etc., are not limited to those illustrated.

  Specifically, in the above-described embodiment, the pair of inner inclined surfaces 20 and 20 are provided on the stopper member 18 that is insert-molded in the inner cylindrical metal member 12, but a pair of annular shapes that are formed independently of each other. An inner inclined surface may be formed on each member, and the annular member may be fitted and fixed to the inner cylinder fitting, or the inner inclined surface may be formed directly on the inner cylinder fitting.

  Moreover, in the said embodiment, although the inner side inclined surface 20 and the outer side inclined surface 22 were made into the taper shape extended continuously around the center axis | shaft of the inner cylinder metal fitting 12, around the center axis | shaft of an inner cylinder metal fitting, for example Further, it may be an arc shape extending with a length less than one round, or a flat shape inclined at a predetermined angle with respect to the central axis. Further, the pair of inner inclined surfaces and outer inclined surfaces partially extending around the central axis can be opposed to each other in one direction perpendicular to the axis with the inner cylinder fitting interposed therebetween.

  In the above embodiment, the inner shock absorbing rubber 30 is attached to the inner inclined face 20 and the outer shock absorbing rubber 32 is attached to the outer inclined face 22. However, only at least one of the shock absorbing rubbers 30 and 32 is provided. It may be adopted.

  Also, for example, a pair of slits are formed on both sides in the direction perpendicular to the axis across the inner cylindrical metal fitting of the main rubber elastic body, and the straight portions formed on both axial sides of the main rubber elastic body are connected to each other by these slits. It is also possible to make it. As a result, the spring ratio in the radial direction in which the pair of slits are formed and in the radial direction perpendicular thereto is set large.

  Therefore, for example, the direction in which the above-described pair of slits are opposed to each other with the inner cylinder bracket interposed therebetween is the vehicle front-rear direction, and the direction orthogonal to the opposite direction is the vehicle lateral direction, so that the lower arm moves toward the vehicle body. By mounting on the mounting part, it is possible to improve the driving comfort by the soft spring characteristic in the vehicle front-rear direction and to improve the driving stability by the hard spring characteristic in the vehicle left-right direction. Since the suspension bush of such a form is made low in spring by a pair of slits, the suspension bush 10 attached to the lateral arm (second lower arm 36) as in the above-described embodiment is closer to the vehicle lateral direction. It is suitably used for a part that is not subjected to a high load, for example, a part where a strut arm that mainly receives a force in the vehicle longitudinal direction is attached to the vehicle body.

  Moreover, in the said embodiment, although the specific example of what applies a suspension bush to a double wishbone type suspension was shown, For example, it is applicable also to the suspension of another suspension system.

When the rear wheel functions as a steered wheel, the suspension bush of the present invention may be attached to the mounting portion of the lateral arm connected to the support member that supports the rear wheel on the vehicle body side.

It is a longitudinal cross-sectional explanatory drawing of the suspension bushing as 1st embodiment of this invention, Comprising: The figure corresponded in the II cross section of FIG. One side explanatory drawing of the suspension bush. The longitudinal cross-sectional explanatory drawing of one operation state at the time of the suspension bush being mounted | worn with the motor vehicle. Schematic for demonstrating the action | operation in the double joint type suspension to which this invention is applied.

Explanation of symbols

10: Suspension bush, 12: Inner cylinder fitting, 14: Outer cylinder fitting, 16: Main rubber elastic body, 20: Inner inclined surface, 22: Outer inclined surface, 30: Inner shock absorbing rubber, 32: Outer shock absorbing rubber, 36: Second lower arm

Claims (6)

In the suspension bush attached to the vehicle body side mounting portion of the suspension arm in the double joint type suspension mechanism, the inner shaft member and the outer cylindrical member spaced apart on the outer peripheral side thereof are connected by a rubber elastic body.
Inner inclined surfaces that gradually decrease in diameter as they go outward in the axial direction are formed at both axial ends of the inner shaft member, respectively, and axially outward at both axial ends of the outer cylinder member The outer inclined surfaces that are gradually reduced in diameter according to the above are formed, while the straight portions extending in the axial direction from both axial end portions of the main rubber elastic body are formed, and the inner inclined surfaces and the outer are formed via the straight portions. The inclined surfaces are opposed to each other in a direction perpendicular to the axis at a predetermined distance from each other, a buffer rubber layer is formed on at least one of the inner inclined surface and the outer inclined surface, and the outer cylinder member is This corresponds to a twist displacement angle until the outer inclined surface is brought into contact with the inner inclined surface via the buffer rubber layer by being relatively displaced with respect to the inner shaft member. The inclination angle of the outer inclined surface with respect to the central axis of the outer cylinder member is set to be smaller than the inclination angle of the inner inclined surface with respect to the central axis of the inner shaft member by an angle α. Suspension bush.   The suspension arm constituting the double joint type suspension mechanism includes a lateral arm extending in the vehicle lateral direction and a strut arm extending in the longitudinal direction of the vehicle, and is attached to a mounting portion of the lateral arm on the vehicle body side. The suspension bush according to claim 1.   A pair of slits are formed on both sides of the inner shaft member in the main rubber elastic body, and the straight portions formed on both sides in the axial direction are connected to each other by the slits. The suspension bush according to 2.   A sleeve-like stopper member is assembled in an extrapolated state with respect to the inner shaft member, and an inner peripheral surface and an outer peripheral surface of the main rubber elastic body are an outer peripheral surface of the stopper member and an inner peripheral surface of the outer cylinder member. The inner inclined surface is formed by both axial end portions of the stopper member, and the outer diameter of the central portion in the axial direction of the stopper member is the maximum outer diameter of the inner inclined surface. The suspension bush according to any one of claims 1 to 3, wherein the suspension bush is smaller than a size.   The inner inclined surface of the inner shaft member is formed with a buffer surface extending in the axial direction with a flat surface or a curved surface at the inner end edge portion having the maximum outer diameter, and further inward in the axial direction of the buffer surface. The suspension bush according to any one of claims 1 to 4, wherein a stepped surface having a reduced diameter is formed on the suspension bush. A lateral arm extending in the lateral direction of the vehicle and a strut arm extending in the longitudinal direction of the vehicle are included. At least one of the lateral arm and the strut arm in the longitudinal direction is disposed on the vehicle body side via the suspension bush. A double joint suspension mechanism in which the other end in the longitudinal direction of the other of the lateral arm and the strut arm is attached to the carrier side via a ball joint.
The suspension bush according to any one of claims 1 to 5, wherein the suspension bushing according to any one of claims 1 to 5 is used, and attachment positions of at least one axial end of the lateral arm and the strut arm to the vehicle body side and the carrier side are connected. A double joint type suspension mechanism, wherein the suspension bush is mounted between the arm and the vehicle body such that a central axis of the suspension bush is perpendicular to an arm axial direction line.

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