Patent Publication Number: US-2021179201-A1

Title: Resin bracket

Description:
TECHNICAL FIELD 
     The present invention relates to a resin bracket, and particularly to a technique for improving strength and improving quality. 
     BACKGROUND ART 
     Conventionally, a cab suspension has been used to improve ride comfort for a cabin in which a crew of a truck boards. In this cab suspension, an air spring for absorbing shock of the cabin such as an air suspension is provided. Additionally, it is known to use a shock absorber to damp periodic vibration of a spring mass system generated by such an air spring (Patent Documents 1, 2). 
     PRIOR ART DOCUMENT 
     Patent Document 
     Patent Document 1: Japanese Patent Laid-Open No. 7-137667 
     Patent Document 2: Japanese Patent Laid-Open No. 11-348819 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     For the cab suspension like the aforementioned Patent Documents 1, 2, a forged metal bracket is used to mount the shock absorber on a cab side. However, the forged bracket has a problem of requirement for machining, coating, and the like, and a high manufacturing cost. 
     From the above, a problem to be solved in this application is to provide a resin bracket capable of suppressing cost while securing quality. 
     Means for Solving the Problems 
     A resin bracket according to this application example includes: a main body made of resin; a fastening counterpart formed integrally with the main body; a metal load-receiving member having an embedded part embedded in the main body, and a shaft part extending from the embedded part; and a reinforcement part having a rib and provided in the main body. 
     According to the resin bracket according to this application example, the reinforcement part having the rib is provided in the main body made of resin, so that the main body can form an inexpensive bracket having moderate toughness and rigidity. Consequently, it is possible to provide a resin bracket capable of suppressing cost while securing quality. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic configuration diagram of a truck mounted with a cab suspension. 
         FIG. 2  is a configuration diagram of the cab suspension. 
         FIG. 3  is a perspective view of a resin bracket according to the present invention. 
         FIG. 4  is a sectional view of a I-I cross section in  FIG. 3 . 
         FIG. 5  is a sectional view of a II-II cross section in  FIG. 4 . 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 
     Referring to  FIG. 1 , a schematic configuration diagram of a truck  1  mounted with a cab suspension  3  is illustrated. 
     In a front part of the truck  1 , a frame  5 , wheels  7 , and a cabin  11  are provided. A leaf spring  9  is disposed between the frame  5  and each wheel  7 . Furthermore, cab suspensions  3  are disposed between the frame  5  and the cabin  11 . Each leaf spring  9  is connected to a driving component  13  at a center in the front-rear direction, and is a suspension for absorbing vibration or shock transmitted from the wheel  7  to the frame  5 . That is, the leaf spring  9  is disposed in order to suppress deterioration and damage of components mainly composing the truck  1 , such as the driving component  13 , the frame  5 , and an engine (not illustrated), due to vibration or shock transmitted from the wheels  7 . 
     The cab suspension  3  further absorbs vibration or shock transmitted from the wheels  7  to the cabin  11  with a configuration described below. That is, the cab suspensions  3  each are a suspension provided in order to mainly improve ride comfort of a crew who boards the cabin  11 . 
     Referring to  FIG. 2 , a configuration diagram of the cab suspension  3  is illustrated. 
     The cab suspension  3  includes a cab hinge unit  21 , a cab support member  23 , an air spring  25 , and a shock absorber unit  27 . One end of an upper support member  33  rotates around a tilt fulcrum  31   a , so that the cab hinge unit  21  can rotate (tilt) the cabin  11  provided above the upper support member  33 . The cab support member  23  has one end connected to a suspension fulcrum  31   b  so as to be rotatable, and rotation of the other end is restricted by the air spring  25  and the shock absorber unit  27 . 
     Specifically, the cab hinge unit  21  includes a lower support member  31  and the upper support member  33 . The lower side in the vertical direction of the lower support member  31  is connected to the frame  5 . The upper side of the lower support member  31  is connected to the upper support member  33  so as to be able to rotate the upper support member  33  at the tilt fulcrum  31   a.    
     The upper support member  33  has the other end connected to the cab support member  23  so as to be able to rotate the cab support member  23  at the suspension fulcrum  31   b.    
     The elastic modulus of the air spring  25  is kept constant by air supplied from an air compressor (not illustrated), and is a so-called constituting member of an air suspension that absorbs shock in the pressing direction or the tensile direction in which the shock is applied to the cabin  11 . 
     In the shock absorber unit  27 , a first fastening part  29   d  of a shock absorber  29  is fixed to the tilt fulcrum  31   a . In the shock absorber unit  27 , a second fastening part  29   c  is fixed to the cab support member  23  through a resin bracket  41  according to the present invention. This shock absorber  29  is an oil damper including a piston rod  29   a  and a cylinder  29   b , and damps force in the piston moving direction, the force being applied to the shock absorber  29  by movement of a piston (not illustrated) connected to the piston rod  29   a  inside the cylinder  29   b.    
     That is, in the cab support member  23 , for example, when one end of the cab support member  23  is rotated around the suspension fulcrum  31   b  by vibration or shock generated by travelling of the truck  1 , the other end of the cab support member  23  absorbs shock by the air spring  25 . The air spring  25  has a constant elastic modulus, so that periodic vibration of a spring mass system generated in the cab support member  23  is damped by the shock absorber  29  of the shock absorber unit  27 . 
     Referring to  FIG. 3 , a perspective view of the resin bracket  41  according to the present invention is illustrated. Fastening counterparts  51  described below are screwed to the cab support member  23  by bolts (fastening members)  65 , so that the resin bracket  41  is assembled. Additionally, a cup washer  63 , the second fastening part  29   c  of the shock absorber  29 , and a flat washer  67  penetrate a shaft part  47  in the aforementioned order, and are screwed by a nut  61 , so that the resin bracket  41  is assembled. 
     As illustrated in  FIG. 2 , when the cab support member  23  rotates to generate pressing force or tensile force in the shock absorber  29 , force in the torsion direction is applied to the resin bracket  41 , in addition to pressing force or tensile force in the predetermined direction. Specifically, when the cab support member  23  rotates with the suspension fulcrum  31   b  as a base point, the second fastening part  29   c  performs circular motion around the suspension fulcrum  31   b . That is, the first fastening part  29   d  is fixed to the tilt fulcrum  31   a , and the second fastening part  29   c  is fixed to the suspension fulcrum  31   b , and therefore when the second fastening part  29   c  performs circular motion around the suspension fulcrum  31   b , force in the torsion direction is applied to the first fastening part  29   d  and the second fastening part  29   c.    
     In order to eliminate this torsion, in the second fastening part  29   c  and the first fastening part  29   d , an elastic member such as rubber is provided on a peripheral edge of the second fastening part  29   c . Consequently, when force in the torsion direction is applied to the second fastening part  29   c , the elastic member is warped, so that it is possible to eliminate torsion to be applied to the second fastening part  29   c  and the first fastening part  29   d.    
     At this time, torsional stress is applied to a load-receiving member  43 , described below, which fixes the resin bracket  41  and the shock absorber  29 . Therefore, the resin bracket  41  needs to have a configuration capable of withstanding torsional stress, pressing force, and tensile force to be applied to the load-receiving member  43 . 
     Referring to  FIG. 4 , a sectional view of a I-I cross section in  FIG. 3  is illustrated. Referring to  FIG. 5 , a sectional view of a II-II cross section in  FIG. 4  is illustrated. Hereinafter, the resin bracket  41  will be described in detail with reference to  FIG. 3  to  FIG. 5 . 
     The resin bracket  41  includes the load-receiving member  43  and a resin member (main body)  45 . The load-receiving member  43  is a forged metal member including a flange part (embedded part)  46  and the shaft part  47 . The flange part  46  is a flat plate member in which a peripheral edge  46   b  of a flat surface  46   a  has a hexagonal shape. 
     The shaft part  47  extends from the center of the flat surface  46   a  of the flange part  46  in the direction perpendicular to the flat surface  46   a . A screw part  47   a  enabling screwing by the nut  61  is formed on a peripheral surface of an end of the shaft part  47 , the end being separated from the flange part  46 . 
     The resin member  45  is a resin member including the fastening counterparts  51 , an outer reinforcement part  53 , an inner reinforcement part  55 , and an outer edge rib part  57 . 
     Specifically, for example, the resin member  45  is so-called fiber reinforced plastic (LEONA 14G manufactured by Asahi Kasei Corporation) formed by using PA66-GF containing glass fiber. The aforementioned resin only needs to contain 30% to 50% glass fiber. 
     In the resin member  45 , the flange part  46  of the load-receiving member  43  is formed so as to be embedded in a part deeper than a bottom surface  55   a  of the inner reinforcement part  55  by insert molding. The flat surface  46   a  and the peripheral edge  46   b  are covered with resin, so that the flange part  46  thus embedded is supported in the direction in which the flange part  46  rotates around the shaft part  47 . 
     That is, when the load-receiving member  43  is twisted in the direction of rotation around the shaft part  47 , the peripheral edge  46   b  is supported by the resin member  45 , so that it is possible to prevent rotation around the shaft part  47 . Particularly, the peripheral edge  46   b  has a hexagonal shape, so that the peripheral edge  46   b  can be firmly supported by the resin member  45 . 
     The fastening counterparts  51  are formed so as to have bearing surfaces  51   a  and openings  51   b , and are provided on both ends of the resin member  45 . Each bearing surface  51   a  is a circular surface located in the direction opposite to a Z direction from a front surface  58 , and parallel to the front surface  58 . Each opening  51   b  is a through hole that penetrates from the center of the bearing surface  51   a  toward a back surface  59 . 
     The inner reinforcement part  55 , and the outer reinforcement part  53  provided around the inner reinforcement part  55  include bottom surfaces  53   a ,  55   a , and ribs  54 ,  56 , respectively. The bottom surfaces  53   a ,  55   a  are surfaces that are parallel to the front surface  58 , and that are formed to be located in order of the bottom surface  55   a  and the bottom surface  53   a  in the direction opposite to the Z direction of the load-receiving member  43  as viewed from the front surface  58 . For convenience of explanation, the front surface  58  is defined as a first surface L 1 , the remaining surfaces are classified into a second surface L 2  to a fifth surface L 5  in the direction opposite to the Z direction. When the back surface  59  is defined as a sixth surface L 6 , the bottom surface  55   a  and the bottom surface  53   a  are formed so as to be located at the second surface L 2  and a fourth surface L 4 , respectively. 
     In the back surface  59 , a recess  59   a  recessed from the sixth surface L 6  toward the fifth surface L 5  is provided at a position corresponding to the outer reinforcement part  53  and the inner reinforcement part  55 . Furthermore, the flange part  46  is embedded at a position corresponding to the inner reinforcement part  55  between a third surface L 3  and the fourth surface L 4 , and the thickness in the Z direction between the second surface L 2  and the third surface L 3  is the same as the thickness between the fourth surface L 4  and the fifth surface L 5 . 
     That is, the thickness in the Z direction of resin provided between the respective surfaces forming the bottom surfaces  53   a ,  55   a  is uniform, and therefore rigidity and toughness are unified, and stress is distributed. 
     The ribs  54 ,  56  are wall-shaped portions extending in the Z direction from the bottom surfaces  53   a ,  55   a , respectively. Specifically, the rib  56  includes a circular rib  56   b  concentric with the shaft part  47 , and radial ribs  56   a  radially extending from the shaft part  47 . Particularly, grooves  56   c  are provided at portions near the shaft part  47  of the radial ribs  56   a , so that a protrusion  63   a  of the cup washer  63  can be prevented from interfering with the radial ribs  56   a . The rib  54  reaches the outer edge rib part  57  forming an outer edge of the resin member  45  from the circular rib  56   b . This rib  54  includes trunk ribs (radial ribs)  54   a  radially extending from the shaft part  47 , and branch ribs  54   b  that reach the outer edge rib part  57  from the trunk ribs  54   a.    
     That is, the radial ribs  56   a  and the trunk ribs  54   a  extending radially as viewed from the shaft part  47  are provided in the resin member  45 , so that the load-receiving member  43  is reinforced in the direction parallel to the front surface  58  (for convenience of explanation, the direction is hereinafter referred to as an XY flat surface direction). Particularly, the branch ribs  54   b  reach the outer edge rib part  57  from the trunk ribs  54   a , so that the trunk ribs  54   a  are reinforced with respect to the direction of rotation around a Z-axis. Additionally, the circular rib  56   b  is provided in the resin member  45 , so that the load-receiving member  43  is reinforced with respect to the direction of rotation around the Z-axis. 
     Furthermore, the outer reinforcement part  53  and the inner reinforcement part  55  have spaces from the front surface  58  to the bottom surfaces  53   a ,  55   a , respectively, and the load-receiving member  43  is made of resin, so that the resin member  45  is reinforced by the ribs  54 ,  56  having predetermined flexibility. Thus, in the outer reinforcement part  53  and the inner reinforcement part  55  that reinforce the resin member  45 , the ribs  54 ,  56  warp toward the spaces when the load-receiving member  43  is pressed in the XY flat surface direction, or twisted in the direction of rotation around the Z-axis. Consequently, it is possible to distribute stress to be applied to each of the ribs  54 ,  56 . 
     With such a configuration, in the resin bracket  41  according to the present invention, even in a case where the resin member  45  as the main body is made of resin which is low in material cost and processing cost such as for machining, and torsional stress, pressing force, and tensile force are applied to the load-receiving member  43  by vibration or shock generated by travelling or the like of the truck  1 , it is possible to fix the second fastening part  29   c  of the shock absorber  29  to the cab support member  23  without damage (secure quality). 
     As described above, the resin bracket according to the present invention includes the resin member  45  made of resin, the fastening counterparts  51  integrally formed with the resin member  45 , the metal load-receiving member including the flange part  46  embedded in the resin member  45  and the shaft part  47  extending from the flange part  46 , and the outer reinforcement part  53  and the inner reinforcement part  55  as the reinforcement part, having the ribs  54 ,  56  and provided in the resin member  45 . 
     Accordingly, the outer reinforcement part  53  and the inner reinforcement part  55  having the ribs  54 ,  56 , respectively are provided in the resin member  45  made of resin, so that the resin member  45  can have moderate toughness and rigidity. For example, the trunk ribs  54   a  and the radial ribs  56   a  that reach in the direction of force applied to the load-receiving member  43  embedded in the resin member  45  are disposed, so that the load-receiving member  43  can be supported while the trunk ribs  54   a  and the radial ribs  56   a  made of the same resin as the resin member  45  moderately warp such that the resin member  45  is not damaged. Furthermore, the resin member  45  is of resin, and therefore corrosion resistance can be enhanced, and rust-proofing such as coating is not required. Furthermore, the resin member  45  as the main body is of resin, and therefore it is possible to reduce size without considering strength in case of corrosion due to rust or the like. Particularly, the resin member  45  is made of resin, and therefore it is possible to reduce weight and cost compared to a case where a bracket made of metal is formed, for example. With such a configuration, the load-receiving member  43  made of metal is firmly provided in the resin member  45  made of resin, and it is possible to enhance corrosion resistance without so-called post-treatment such as surface treatment, and form a lightweight and inexpensive bracket. 
     The reinforcement part includes the inner reinforcement part  55  in contact with the shaft part  47 , and the outer reinforcement part  53  provided around the inner reinforcement part  55 , and the height of the rib  56  of the inner reinforcement part  55  in the Z direction from the bottom surface  55   a  is lower than the height of the rib  54  of the outer reinforcement part  53 . 
     Accordingly, the height of the rib  56  of the inner reinforcement part  55  on which force to be applied to the load-receiving member  43  is concentrated is reduced, so that it is possible to enhance the rigidity of the resin member  45  in the vicinity of the load-receiving member  43 . On the other hand, the height of the rib  56  of the outer reinforcement part  53  is increased, so that it is possible to enhance the toughness of the outer reinforcement part  53 . 
     Thus, while the rigidity of the inner reinforcement part  55  is enhanced, the toughness of the outer reinforcement part  53  is enhanced, so that the resin member  45  supporting the load-receiving member  43  is reinforced by the inner reinforcement part  55 , the inner reinforcement part  55  having enhanced rigidity is provided, the outer reinforcement part  53  having enhanced toughness of the resin member  45  near the inner reinforcement part  55  is provided around the inner reinforcement part  55 , and the resin member  45  can be formed so as to moderately have the rigidity and the toughness as the whole of the resin member  45 . 
     The resin constituting the resin member  45  contains 30% to 50% glass fiber. 
     Accordingly, the resin member  45  can maintain the toughness by flexibility as resin while enhancing the rigidity. 
     Particularly, the load-receiving member  43  supports the shock absorber  29  provided at such a position as not to be exposed to high-temperature heat of an engine and the like, and therefore it is possible to support a member to which shearing stress and torsional stress by pressing or tension are applied on a fastening portion. 
     The description of the resin bracket according to the present invention will be finished. The present invention is not limited to the aforementioned embodiment, and can be changed without departing from the spirit of the invention. 
     For example, in this embodiment, the resin bracket  41  is provided in order to support the shock absorber  29  provided in the cab suspension  3  of the truck  1 . However, the resin bracket may be provided in order to support a shock absorber for a two-wheeled vehicle or the like, or may be used for a real estate such as a house. 
     In this embodiment, the resin member  45  is formed of PA66-GF50 containing 50% glass fiber. However, the present invention is not limited to this, and any resin having strength may be used. 
     &lt;Aspects of Present Invention&gt; 
     A resin bracket according to a first aspect of the present invention includes: a main body made of resin; a fastening counterpart formed integrally with the main body; a metal load-receiving member having an embedded part embedded in the main body, and a shaft part extending from the embedded part; and a reinforcement part having a rib and provided in the main body. 
     In the resin bracket according to the first aspect of the present invention, the reinforcement part having the rib is provided in the main body made of resin, and therefore the main body can have moderate toughness and rigidity. For example, the rib extending in the direction of force applied to the load-receiving member embedded in the main body is disposed, so that the load-receiving member can be reinforced while the rib made of resin moderately warp such that the main body made of resin is not damaged. Furthermore, the main body is of resin, and therefore corrosion resistance can be enhanced, and rust-proofing such as coating is not required. Furthermore, the main body is of resin, and therefore it is possible to reduce size without considering strength in case of corrosion due to rust or the like. Particularly, the main body is made of resin, and therefore it is possible to reduce weight and cost compared to a case where a bracket made of metal is formed, for example. With such a configuration, the load-receiving member made of metal is firmly provided in the main body made of resin, and it is possible to enhance corrosion resistance without so-called post-treatment such as surface treatment, and form a lightweight and inexpensive bracket. 
     From the above, in the first aspect, it is possible to provide a resin bracket capable of suppressing cost while securing quality. 
     According to a resin bracket according to a second aspect of the present invention, in the aforementioned first aspect, the reinforcement part is provided with a plurality of the ribs. Consequently, it is possible to distribute force to be applied to one rib, and prevent stress concentration. 
     According to a resin bracket according to a third aspect of the present invention, in the aforementioned second aspect, the reinforcement part is provided with a bottom surface between the ribs, and the ribs have different heights from the bottom surface in a direction in which the shaft part extends. Consequently, rigidity and toughness can be adjusted by the heights of the ribs. 
     According to a resin bracket according to a fourth aspect of the present invention, in the aforementioned third aspect, the reinforcement part includes an inner reinforcement part in contact with the shaft part, and an outer reinforcement part provided around the inner reinforcement part, and the height of the rib of the inner reinforcement part from the bottom surface in the direction in which the shaft part extends is lower than the height of the rib of the outer reinforcement part. Consequently, the height of the rib of the inner reinforcement part on which force to be applied to the load-receiving member is concentrated is reduced, so that it is possible to enhance the rigidity of the main body near the load-receiving member. On the other hand, the height of the rib of the outer reinforcement part is increased, so that it is possible to enhance the toughness of the outer reinforcement part. 
     According to a resin bracket according to a fifth aspect of the present invention, in the aforementioned third or fourth aspect, resin forming the bottom surface in the main body has a uniform thickness in the direction in which the shaft part extends. Consequently, the thickness of the resin forming the bottom surface is uniformed, rigidity or toughness of the resin forming the bottom surface is unified, and stress concentration on a part of the resin forming the bottom surface is suppressed. 
     According to a resin bracket according to a sixth aspect of the present invention, in any of the aforementioned first to fifth aspects, the reinforcement part has a circular rib having a circular shape and surrounding the load-receiving member. Consequently, the load-receiving member is reinforced with respect to the direction of rotation around the shaft part. 
     According to a resin bracket according to a seventh aspect of the present invention, in any of the aforementioned first to sixth aspects, the reinforcement part has a radial rib radially extending from the load-receiving member. Consequently, the load-receiving member is reinforced in the direction along the radial rib from the load-receiving member. 
     According to a resin bracket according to an eighth aspect of the present invention, in the aforementioned seventh aspect, the reinforcement part further has a branch rib branched from the radial rib. Consequently, the radial rib is reinforced with respect to the direction of rotation around the shaft part. 
     According to a resin bracket according to a ninth aspect of the present invention, in any of the aforementioned first to eighth aspects, the resin constituting the main body contains 30% to 50% glass fiber. Consequently, the main body can maintain the toughness by flexibility as resin while enhancing the rigidity. 
     According to a resin bracket according to a tenth aspect of the present invention, in any of the aforementioned first to ninth aspects, the shaft part is provided with a screw part on a circumferential surface thereof. Consequently, a penetrated member that penetrates the shaft part to be connected can be screwed by providing a nut on the screw part, and the penetrated member can be firmly fastened to the shaft part. 
     According to a resin bracket according to an eleventh aspect of the present invention, in any of the aforementioned first to tenth aspects, the load-receiving member is mounted on a shock absorber of a cab suspension, and supports the shock absorber. Consequently, the load-receiving member supports the shock absorber provided at such a position as not to be exposed to high-temperature heat of an engine and the like, so that the main body made of resin can be made not to be exposed to high-temperature heat. Additionally, the main body can support a member to which shearing stress and torsional stress by pressing or tension are applied on a fastening portion such as a shock absorber of the cab suspension through the shaft part. 
     EXPLANATION OF REFERENCE SIGNS 
     
         
           3  cab suspension 
           29  shock absorber 
           41  resin bracket 
           43  load-receiving member 
           45  resin member (main body) 
           46  flange part (embedded part) 
           47  shaft part 
           47   a  screw part 
           51  fastening counterpart 
           51   a  bearing surface 
           51   b  opening 
           53  outer reinforcement part 
           53   a ,  55   a  bottom surface 
           54 ,  56  rib 
           54   a  trunk rib (radial rib) 
           54   b  branch rib 
           55  inner reinforcement part 
           56   a  radial rib 
           56   b  circular rib 
           65  bolt (fastening member)