Patent Publication Number: US-2022212512-A1

Title: Suspension device

Description:
BACKGROUND 
     Technical Field 
     The invention relates to a suspension device. 
     Description of Related Art 
     Conventionally, suspension devices are known to be provided in a vehicle or the like, and have a cushioning function for preventing the vibration caused by unevenness of a road surface from being transmitted to a vehicle body through the wheels and improve the riding comfort and steering stability of the vehicle. A leaf spring type suspension device, among the suspension devices, is configured by using a leaf spring (see, for example, Patent Document 1). 
     The leaf spring is attached to an arm that supports the wheels and a member that supports the vehicle body. Specifically, the leaf spring is attached to a right arm that supports the right wheel, a left arm that supports the left wheel, and a member that supports the vehicle body. 
     Related Art 
     Patent Document 
     [Patent Document 1] Japanese Laid-Open No. 11-263109 
     SUMMARY 
     Problems to be Solved 
     However, in the conventional suspension device, the leaf spring is attached to the member, and therefore the vibration from the wheels is transmitted to the vehicle body through the member with the leaf spring as a transmission path. If the vibration is transmitted to the vehicle body, the quality of riding comfort and the steering stability may deteriorate. 
     In view of the above, the invention provides a suspension device that can suppress the vibration from the wheels from being transmitted to the vehicle body. 
     Means for Solving the Problems 
     Accordingly, the suspension device according to the invention includes: a leaf spring that extends in a belt shape; a first arm; a second arm; and a coupling member that rotatably couples the first arm and the second arm. The suspension device is characterized in having: a first holding part that holds one end of the leaf spring; and a second holding part that holds an other end of the leaf spring, and the first arm and the second arm support the leaf spring by at least one portion that is different from the one end and the other end of the leaf spring. 
     Further, the suspension device according to the invention is characterized in that, in the above-mentioned invention, a support position of the leaf spring supported by the first arm and the second arm is located between a first coupling position between the first arm and the coupling member and a second coupling position between the second arm and the coupling member. 
     Further, the suspension device according to the invention is characterized in that, in the above-mentioned invention, the first holding part is provided on the first arm, and the second holding part is provided on the second arm. 
     Further, the suspension device according to the invention is characterized in that, in the above-mentioned invention, the leaf spring is made of fiber reinforced plastics. 
     Effects 
     According to the invention, the effect of suppressing the vibration from the wheels from being transmitted to the vehicle body is achieved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view schematically showing a configuration of a suspension device according to an embodiment of the invention. 
         FIG. 2  is a cross-sectional view taken along the line A-A shown in  FIG. 1 . 
         FIG. 3  is a view showing an example of a curved mode of the leaf spring of the suspension device according to an embodiment of the invention. 
         FIG. 4  is a view showing an example of the curved mode of the leaf spring of the suspension device according to an embodiment of the invention. 
         FIG. 5  is a perspective view schematically showing a configuration of main parts of the suspension device according to the first modification of the embodiment of the invention. 
         FIG. 6  is a perspective view schematically showing a configuration of the suspension device according to the second modification of the embodiment of the invention. 
         FIG. 7  is a perspective view schematically showing a configuration of the suspension device according to the third modification of the embodiment of the invention. 
         FIG. 8  is a perspective view schematically showing a configuration of the suspension device according to the fourth modification of the embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, embodiments for carrying out the invention will be described in detail together with drawings. Nevertheless, the invention is not limited to the following embodiments. In addition, each of the drawings referred to in the following description merely schematically shows the shape, size, and positional relationship to an extent that allows the content of the invention to be understood. That is to say, the invention is not limited to the shape, size, and positional relationship exemplified in each drawing. 
     First Embodiment 
       FIG. 1  is a perspective view schematically showing a configuration of a suspension device according to an embodiment of the invention.  FIG. 2  is a cross-sectional view taken along the line A-A shown in  FIG. 1 . The suspension device  1  is provided in, for example, a vehicle and is interposed between a right wheel, a left wheel, and a vehicle body (body) to suppress the vibration transmitted from the wheels from being transmitted to the vehicle body. 
     The suspension device  1  includes a right arm  11  that supports the right wheel, a left arm  12  that supports the left wheel, a member  13  that supports the vehicle body, and a leaf spring  14  that elastically deforms in response to the vibration from the wheels. The suspension device  1  is attached to the vehicle body via the member  13  and absorbs the vibration transmitted from the wheels according to the unevenness of a road surface. The wheels are supported by the arms via a knuckle, a disc rotor, etc. In  FIG. 1 , an X direction corresponds to a left-right direction of the vehicle when attached to the vehicle body, a Y direction corresponds to a front-rear direction of the vehicle, and a Z direction corresponds to an up-down direction of the vehicle. 
     The right arm  11  has a support part  11   a  that supports the right wheel, a supported part  11   b  that is provided on a side opposite to a wheel support side of the support part  11   a  and is supported by the member  13 , a grip part  11   c  that extends to a side of the supported part  11   b  opposite to the side of the support part  11   a  and grips a part of the leaf spring  14 , and a holding part  11   d  that holds one end of the leaf spring  14 . The holding part  11   d  corresponds to the first holding part. 
     The left arm  12  has a support part  12   a  that supports the left wheel, a supported part  12   b  that is provided on a side opposite to a wheel support side of the support part  12   a  and is supported by the member  13 , a grip part  12   c  that extends to a side of the supported part  12   b  opposite to the side of the support part  12   a  and grips a part of the leaf spring  14 , and a holding part  12   d  that holds the other end of the leaf spring  14 . The holding part  12   d  corresponds to the second holding part. 
     The member  13  supports the vehicle body and is interposed between the vehicle body and the right wheel, the right arm  11 , the left wheel, and the left arm  12 . The member  13  has an arm support part  13   a  that supports the right arm  11 , an arm support part  13   b  that supports the left arm  12 , and a main body part  13   c  that extends in the X direction (the left-right direction of the vehicle body) and connects to the right arm  11  and the left arm  12 . The arm support parts  13   a  and  13   b  extend in a direction (Y direction) perpendicular to the direction (X direction) in which the main body part  13   c  extends. The arm support part  13   a  rotatably supports the right arm  11  around a rotation axis Y 1  extending in the Y direction. The arm support part  13   b  rotatably supports the left arm  12  around a rotation axis Y 2  extending in the Y direction. The member  13  corresponds to the coupling member that rotatably couples the right arm  11  and the left arm  12 . The member  13  may be integrated with the vehicle body. When the member  13  is integrated with the vehicle body, the vehicle body functions as the coupling member for coupling the right arm  11  and the left arm  12 . 
     The leaf spring  14  forms a belt shape and extends in the X direction. The leaf spring  14  is formed by using, for example, fiber reinforced plastics (FRP), metal, or resin. The leaf spring may be made of one plate material or may be made by laminating a plurality of plate materials. In designing the shape, elastic force, etc. of the leaf spring  14 , FRP is more flexible in its design than metal or resin. 
     Here, the holding parts  11   d  and  12   d  respectively accommodate and hold the end portions of the leaf spring  14 . In this specification, accommodating a part of a member, surrounding a member surface, and restraining and holding a movement of the member in a vertical direction (here, the Z direction), a movement in a horizontal direction (here, the Y direction), and a rotational movement are referred to as surface support. The holding parts  11   d  and  12   d  hold the end portions of the leaf spring  14  by surface support. The leaf spring  14  can move in a direction of being inserted into or removed from the holding parts  11   d  and  12   d.    
     Further, the grip part  11   c  is formed with protrusions  11   e  respectively on two grip surfaces that are surfaces for gripping the leaf spring  14  and face each other. The grip part  11   c  sandwiches and supports the leaf spring  14  with the protrusions  11   e . In this specification, supporting a part of a member at a point or line with protrusions or the like is referred to as point support. In the point support, the leaf spring  14  is supported by an area so as to rotate with the protrusions  12   e  as a fulcrum. The grip part  11   c  supports the leaf spring  14  by point support. On the other hand, in the surface support described above, the leaf spring  14  is in a state where it cannot be rotated by the holding parts  11   d  and  12   d  even when a load is applied from the arms. 
     Further, the grip part  12   c  is formed with protrusions  12   e  respectively on two grip surfaces that are surfaces for gripping the leaf spring  14  and face each other. The grip part  12   c  point-supports the leaf spring  14  with the protrusions  12   e.    
     A support position of the leaf spring  14  supported by the grip part  11   c  (protrusions  11   e ) is on an inner side (the side opposite to the right wheel side) with respect to a coupling position (rotation axis Y 1 ) between the right arm  11  and the member  13 . Furthermore, a support position of the leaf spring  14  supported by the grip part  12   c  (protrusions  12   e ) is on an inner side (the side opposite to the left wheel side) with respect to a coupling position (rotation axis Y 2 ) between the left arm  12  and the member  13 . The support position of the leaf spring  14  supported by the grip part  11   c  and the support position of the leaf spring  14  supported by the grip part  12   c  are both located between the rotation axis Y 1  and the rotation axis Y 2 . 
       FIG. 3  and  FIG. 4  are views showing an example of a curved mode of the leaf spring of the suspension device according to an embodiment of the invention.  FIG. 3  is a view showing a state where the leaf spring  14  is deformed due to the displacement of the arms. Further,  FIG. 4  is a view showing a state of curving in a mode opposite to that of  FIG. 3 . As shown in  FIG. 3  and  FIG. 4 , even when the leaf spring  14  is deformed due to the displacement of the arms, the member  13  is not affected by the deformation. In the suspension device  1 , even if the leaf spring  14  is deformed, the member  13  is not deformed. That is, in the suspension device  1 , when vibration is transmitted from the arms to the leaf spring  14 , the leaf spring  14  absorbs the vibration and the vibration is not transmitted to the member  13 . At this time, since the right arm  11  and the left arm  12  are rotatably supported by the member  13 , and a load due to the fluctuation is converted into a rotational force, the vibration of the arms is suppressed from being transmitted to the member  13 . 
     In the embodiment described above, the leaf spring  14  is supported by the right arm  11  and the left arm  12 , and the leaf spring  14  absorbs the vibration transmitted by the displacement of the arms, and the vibration due to the deformation (displacement) of the leaf spring  14  is not directly transmitted to the member  13 . Therefore, the vibration from the wheels can be suppressed from being transmitted to the vehicle body. Furthermore, in the suspension device  1 , for example, when the vehicle body is tilted (rolled) and one wheel is displaced to the upper side (vehicle body side) and the other wheel is displaced to the opposite side (here, the opposite side in the Z direction), the leaf spring  14  is deformed or returns to its original shape, thereby suppressing the inclination (roll angle) of the vehicle body. 
     In addition, in the embodiment, since the leaf spring  14  is arranged in an arrangement area of the arms, an arrangement space for the leaf spring  14  can be efficient. (First modification of the embodiment) 
       FIG. 5  is a perspective view schematically showing a configuration of main parts of the suspension device according to the first modification of the embodiment of the invention. The above-described embodiment illustrates an example in which the holding part  11   d  holds the leaf spring  14  by surface support, but in the first modification, the holding part holds the leaf spring  14  by point support. In the first modification, the configuration is the same as that of the above-described embodiment except for the configuration of the holding part of the right arm. Hereinafter, the configuration of the holding part  11   f  of the right arm will be described. 
     The holding part  11   f  holds one end of the leaf spring  14 . The holding part  11   f  accommodates and holds the end portion of the leaf spring  14 . The holding part  11   f  is formed with protrusions  11   g  respectively on two surfaces that are surfaces for accommodating the leaf spring  14  and face each other. The holding part  11   f  supports the leaf spring  14  by point support. 
     Even when the holding part  11   f  of the right arm point-supports the leaf spring  14  as in the first modification described above, the vibration is not transmitted to the member  13  due to the deformation (displacement) of the leaf spring  14 , and therefore the vibration from the wheels can be suppressed from being transmitted to the vehicle body. 
     The holding part provided on the left arm may also be configured to point-support the leaf spring  14 . Further, the leaf spring  14  may be configured to be surface-supported in the grip parts  11   c  and  12   c . In regard to the point support and the surface support, a spring constant of the leaf spring  14  changes even if the support position is the same. A support mode may be changed to adjust the spring constant of the leaf spring  14 . Further, in addition to the surface support and the point support, a hinge support configuration that allows rotation along the movement of the leaf spring  14  may be used. 
     Second Modification of the Embodiment 
       FIG. 6  is a perspective view schematically showing a configuration of the suspension device according to the second modification of the embodiment of the invention. The suspension device  1 A according to the second modification includes a right arm  11 A that supports the right wheel, a left arm  12 A that supports the left wheel, a member  13  that supports the vehicle body, a leaf spring  14  that elastically deforms in response to the vibration from the wheels, and a grip part  15  that grips the leaf spring  14 . Since the member  13  and the leaf spring  14  have the same configuration as that of the embodiment, the description thereof is omitted. 
     The right arm  11 A has a support part  11   a  that supports the right wheel, a supported part  11   b  that is provided on a side opposite to a wheel support side of the support part  11   a  and is supported by the member  13 , a holding part  11   d  (see  FIG. 2 ) that holds one end of the leaf spring  14 , and a coupling part  11   h  that extends to a side of the supported part  11   b  opposite to the side of the support part  11   a  and is connected to the grip part  15 . 
     The left arm  12 A has a support part  12   a  that supports the left wheel, a supported part  12   b  that is provided on a side opposite to a wheel support side of the support part  12   a  and is supported by the member  13 , a holding part  12   d  (see  FIG. 2 ) that holds the other end of the leaf spring  14 , and a coupling part  12   f  that extends to a side of the supported part  12   b  opposite to the side of the support part  12   a  and is connected to the grip part  15 . 
     The grip part  15  forms an annular shape and grips a central portion of the leaf spring  14  in a longitudinal direction. A support position of the leaf spring  14  supported by the grip part  15  is located between a coupling position (rotation axis Y 1 ) between the right arm  11 A and the member  13  and a coupling position (rotation axis Y 2 ) between the left arm  12 A and the member  13 . 
     The coupling parts  11   h  and  12   f  are connected to the grip part  15  at different positions. The right arm  11 A grips the leaf spring  14  by the grip part  15  via the coupling part  11   h . The left arm  12 A grips the leaf spring  14  by the grip part  15  via the coupling part  12   f . The right arm  11 A and the left arm  12 A support the leaf spring by the common grip part  15 . In the second modification, a bearing or the like may be provided between the grip part  15  and at least one of the right arm  11  and the left arm  12  for the right arm  11  and the left arm  12  to rotate independently of the grip part  15 . 
     In the suspension device  1 A, when vibration is transmitted from the arms to the leaf spring  14 , the leaf spring  14  also absorbs the vibration and the vibration is not transmitted to the member  13 . 
     In the second modification described above, the leaf spring  14  is supported by the right arm  11 A and the left arm  12 A, and the leaf spring  14  absorbs the vibration transmitted by the displacement of the arms, and the vibration due to the deformation (displacement) of the leaf spring  14  is not transmitted to the member  13 . Therefore, the vibration from the wheels can be suppressed from being transmitted to the vehicle body. 
     Third Modification of the Embodiment 
       FIG. 7  is a perspective view schematically showing a configuration of the suspension device according to the third modification of the embodiment of the invention. The above-described embodiment and first and second modifications illustrate examples in which the arms hold the leaf spring, but in the third modification, links (first link  16  and second link  17 ) connected to the arms  11  and  12  hold the leaf spring. The suspension device  1 B according to the third modification includes a right arm  11  that supports the right wheel, a left arm  12  that supports the left wheel, a member  13  that supports the vehicle body, a leaf spring  14  that elastically deforms in response to the vibration from the wheels, a first link  16  that grips one end of the leaf spring  14  and is connected to the right arm  11 , and a second link  17  that grips the other end of the leaf spring  14  and is connected to the left arm  12 . In the third modification, the configuration is the same as that of the above-described embodiment except for the configuration of the links and that the right arm  11  and the left arm  12  do not have the holding parts  11   d  and  12   d . Hereinafter, the configuration of the first link  16  and the second link  17  will be described. 
     The first link  16  has a holding part  16   a  that holds one end of the leaf spring  14 , and a connecting part  16   b  that connects to the right arm  11 . The holding part  16   a  is rotatably supported by the connecting part  16   b  around an axis parallel to the Y direction. The holding part  16   a  is supported by the connecting part  16   b  by, for example, a pin or a ball joint. The connecting part  16   b  is rotatably supported by the right arm  11  around an axis parallel to the Y direction. The connecting part  16   b  is supported by the right arm  11  by, for example, a pin or a ball joint. The holding part  16   a  corresponds to the first holding part. 
     The second link  17  has a holding part  17   a  that holds the other end of the leaf spring  14 , and a connecting part  17   b  that connects to the left arm  12 . The holding part  17   a  is rotatably supported by the connecting part  17   b  around an axis parallel to the Y direction. The holding part  17   a  is supported by the connecting part  17   b  by, for example, a pin or a ball joint. The connecting part  17   b  is rotatably supported by the left arm  12  around an axis parallel to the Y direction. The connecting part  17   b  is supported by the left arm  12  by, for example, a pin or a ball joint. The holding part  17   a  corresponds to the second holding part. In  FIG. 7 , the first link  16  and the second link  17  respectively support the leaf spring  14  by surface support, but may support the leaf spring  14  by point support. 
     Even when the link connected to each arm holds the leaf spring  14  as in the third modification described above, the vibration is not transmitted to the member  13  due to the deformation (displacement) of the leaf spring  14 , and therefore the vibration from the wheels can be suppressed from being transmitted to the vehicle body. 
     Fourth Modification of the Embodiment 
       FIG. 8  is a perspective view schematically showing a configuration of the suspension device according to the fourth modification of the embodiment of the invention. In the fourth modification, a knuckle that is interposed between the wheel and the arm and supports a bearing holds the leaf spring. The suspension device  1 C according to the third modification includes a right arm  11  that supports the right wheel, a left arm  12  that supports the left wheel, a member  13  that supports the vehicle body, a leaf spring  14  that elastically deforms in response to the vibration from the wheels, a first knuckle  18  that grips one end of the leaf spring  14  and is connected to the right arm  11 , and a second knuckle  19  that grips the other end of the leaf spring  14  and is connected to the left arm  12 . In the fourth modification, the configuration is the same as that of the above-described embodiment except for the configuration of the knuckle and that the right arm  11  and the left arm  12  do not have the holding parts  11   d  and  12   d . Hereinafter, the configuration of the first knuckle  18  and the second knuckle  19  will be described. 
     The first knuckle  18  has a holding part  18   a  that holds one end of the leaf spring  14 , and a connecting part  18   b  that supports the bearing and connects to the right arm  11 . The holding part  18   a  is rotatably supported by the connecting part  18   b  around an axis parallel to the Y direction. The holding part  18   a  is supported by the connecting part  18   b  by, for example, a pin or a ball joint. The connecting part  18   b  is rotatably supported by the right arm  11  around an axis parallel to the Y direction. The connecting part  18   b  is supported by the right arm  11  by, for example, a pin or a ball joint. The holding part  18   a  corresponds to the first holding part. 
     The second knuckle  19  has a holding part  19   a  that holds the other end of the leaf spring  14 , and a connecting part  19   b  that supports the bearing and connects to the left arm  12 . The holding part  19   a  is rotatably supported by the connecting part  19   b  around an axis parallel to the Y direction. The holding part  19   a  is supported by the connecting part  19   b  by, for example, a pin or a ball joint. The connecting part  19   b  is rotatably supported by the left arm  12  around an axis parallel to the Y direction. The connecting part  19   b  is supported by the left arm  12  by, for example, a pin or a ball joint. The holding part  19   a  corresponds to the second holding part. In  FIG. 8 , the first knuckle  18  and the second knuckle  19  respectively support the leaf spring  14  by surface support, but may support the leaf spring  14  by point support. 
     Even when the knuckle connected to each arm holds the leaf spring  14  as in the fourth modification described above, the vibration is not transmitted to the member  13  due to the deformation (displacement) of the leaf spring  14 , and therefore the vibration from the wheels can be suppressed from being transmitted to the vehicle body. 
     As in the third and fourth modifications, a member which is separate from the arms and is provided between the vehicle body and the wheels and related to the connection between them may be configured to hold the leaf spring. Further, in the third and fourth modifications, the support position of the leaf spring  14  supported by the right arm and the left arm may be set to the position of the second modification. 
     Although the embodiments for carrying out the invention have been described above, the invention should not be construed as being limited to the above-described embodiments only. Thus, the invention may include various embodiments not described here, and it is possible to make various changes in design within the scope that does not deviate from the technical idea defined by the claims. 
     In the above-described embodiments and modifications, a cushioning member such as rubber may be provided in a portion of the arm that comes into contact with the leaf spring, and the leaf spring may be supported via the cushioning member. 
     Further, the above-described embodiments and modifications illustrate examples in which the leaf spring is gripped between the coupling position between the right arm and the member and the coupling position between the left arm and the member. However, the leaf spring may be supported at a position overlapping the coupling position when viewed from the Z direction, or the leaf spring may be supported on the wheel side (outer side) with respect to the coupling position. 
     Besides, in the above-described embodiments and modifications, a gripping position of the leaf spring  14  gripped by the grip part may be movable by an actuator or the like. 
     In addition, in the above-described embodiments and modifications, the leaf spring may be supported by a plurality of portions such as 5 or more. 
     Further, the suspension devices according to the above-described embodiments and modifications may be provided in a vehicle in combination with another suspension device such as a suspension device using a coil spring. 
     INDUSTRIAL APPLICABILITY 
     As described above, the suspension device according to the invention is suitable for suppressing the vibration from the wheels from being transmitted to the vehicle body. 
     DESCRIPTIONS OF REFERENCE NUMERALS 
       1 ,  1 A to  1 C suspension device
   11 ,  11 A right arm
   11   a ,  12   a  support part
   11   b ,  12   b  supported part
   11   c ,  12   c ,  15  grip part
 
 11   d ,  11   f ,  12   d  holding part
 
 11   e ,  11   g ,  12   e  protrusion
 
 12 ,  12 A left arm
 
 13  member
 
 13   a ,  13   b  arm support part
 
 13   c  main body part
 
 14  leaf spring
 
 15  grip part
 
 16  first link
 
 17  second link
 
 18  first knuckle
 
 19  second knuckle