Patent Publication Number: US-2022221018-A1

Title: Air damper

Description:
TECHNICAL FIELD 
     The present invention relates to an air damper used for braking, for example, an opening and closing operation of a glove box of an automobile. 
     BACKGROUND ART 
     As a type of an air damper, the following Patent Literature 1 discloses an air damper. The air damper includes: a cylinder having a wall portion extending in a cylindrical shape, a closing portion being provided at one end of the wall portion, the other end side being open, and an engagement hole being formed in a peripheral wall on the other end opening side; a piston slidably inserted into the cylinder; a rod extending from the piston; a flow passage communicating an internal space surrounded by the closing portion of the cylinder and the piston to the outside; a braking force applying unit for narrowing the flow passage to apply a braking force to the piston when the piston slides in a direction away from or close to the closing portion of the cylinder, and widening the flow passage to release the braking force of the piston when the piston moves in a direction opposite the above direction; and a cap attached to an opening at the other end of the cylinder and having an opening portion from which the rod extends. The cap includes a base portion that covers the opening at the other end of the cylinder in a state where the rod extends from the opening portion, an insertion portion that is inserted into the cylinder, and a deflectable locking claw that engages with an engagement hole of the cylinder from an inner peripheral side of the cylinder. One of the piston and the rod is provided with a stopper portion that comes into contact with the cap to regulate further pull-out of the rod when the rod is pulled out to a maximum extent from the opening at the other end of the cylinder, and is provided with a deflection regulating portion that is positioned on a back side of the locking claw to regulate deflection of the locking claw toward the inside of the cylinder when the stopper portion comes into contact with the cap. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: Japanese Patent No. 6402015 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     In the air damper of Patent Literature 1, the locking claw engaging with the engagement hole of the cylinder of the cap is provided at a portion facing the peripheral wall of the cylinder so as to face a direction of a rotation axis when the end portion of the rod is rotatably attached to a glove box and the like, an inner side of the locking claw forms an inner surface perpendicular to the rotation axis, and a deflection regulating portion provided in one of the piston and the rod is disposed on an inner side thereof. 
     On the other hand, in an air damper attached to a glove box and the like of an automobile, when the glove box is detached for maintenance and the like, a rod may largely swing with respect to a cylinder in a state where the rod is pulled out to a maximum extent. 
     In such a case, when a swinging direction of the rod is a direction of the rotation axis, since the deflection regulating portion is disposed inside the locking claw, a retaining action of the locking claw acts, but in a case where the rod swings largely in a direction intersecting the direction of the rotation axis, there is a possibility that the deflection regulating portion is displaced with respect to the locking claw and the retaining action does not act. 
     Therefore, an object of the present invention is to provide an air damper which can sufficiently obtain a retaining effect of a locking claw of a cap attached to a cylinder. 
     Solution to Problem 
     In order to achieve the above object, an air damper of the present invention includes: a cylinder having one end closed and the other end opened; a piston member including a piston inserted into the cylinder and a rod connected to the piston and protruding from the opening; and a cap having an insertion hole for the rod and attached to the opening, in which a plurality of engagement holes are formed in an edge portion of the opening of the cylinder, the cap is formed with an engagement claw which is inserted into the opening and is fitted into the engagement hole from an inner side of the engagement hole, the piston member includes a stopper portion that comes into contact with the cap when the rod is pulled out to a maximum extent, and a deflection regulating portion that is positioned inside the engagement claw in a state of being pulled out to the maximum extent and regulates inward deflection of the engagement claw, an attachment portion that is rotatably attached to an attachment target portion is provided at an end portion of the rod that protrudes from the opening, and a contact surface is formed on the inner side of the engagement claw, the contact surface being capable of coming into contact with the deflection regulating portion even when the rod swings in a direction of a rotation axis of the attachment portion with respect to the attachment target portion or in a direction intersecting the rotation axis when viewed in an axial direction of the cylinder. 
     Advantageous Effects of Invention 
     According to the present invention, when the piston rod is pulled out to the maximum extent with respect to the cylinder, the stopper portion comes into contact with the cap, and further pulling out is regulated. In this state, even if the rod swings with respect to the cylinder in the direction of the rotation axis of the attachment portion or in the direction intersecting with the rotation axis, the deflection regulating portion formed in the piston or the rod comes into contact with the contact surface of the inner side of the engagement claw of the cap to regulate the deflection to the inner side, and therefore, the engagement claw can be prevented from coming off and the cap can be more reliably prevented from coming off. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an exploded perspective view showing an air damper according to an embodiment of the present invention. 
         FIG. 2  is a perspective view of the air damper. 
         FIG. 3  is a partially enlarged perspective view of a piston rod of the air damper. 
         FIG. 4  is a perspective view of a cap of the air damper as viewed from a back surface side. 
         FIG. 5  is a cross-sectional view taken along an axial direction of a cylinder in a state in which the piston rod of the air damper is pulled out to a maximum extent, the cross-sectional view being cut at a portion to which the cap is attached. 
         FIG. 6  is a cross-sectional view taken along the axial direction of the cylinder when the piston rod of the air damper swings in a predetermined direction, the cross-sectional view being cut at a portion to which the cap is attached. 
         FIG. 7  is a cross-sectional view taken along the axial direction of the cylinder when the piston rod of the air damper swings in a direction different from that of  FIG. 6 , the cross-sectional view being cut at a portion to which the cap is attached. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of an air damper according to the present invention will be described with reference to the drawings. 
     As shown in  FIGS. 1 and 2 , an air damper  100  includes a cylinder  200 , a piston rod  300 , and a cap  400 . 
     One end of the cylinder  200  forms a closing end portion  202 , and the other end of the cylinder  200  forms an opening end portion  203 . A plurality of, in this embodiment, a total of four engagement holes  204  are formed at predetermined intervals along a peripheral direction in an opening edge portion of the opening end portion  203 . Further, a pair of cutout portions  205  are formed at positions facing each other in a radial direction. 
     A plate-like bracket  206  extending along an axial direction is formed on an outer periphery of the cylinder  200 , and attachment holes  207  are formed in both end portions of the bracket  206 , respectively. The attachment hole  207  is used for attachment to one side of an opening and closing member such as a glove box. 
     The piston rod  300  includes a piston  301  that is inserted into the cylinder  200 , and a rod  302  that is connected to the piston  301  and protrudes from the opening end portion  203  of the cylinder  200 . The piston rod  300  constitutes a piston member in the present invention. The piston  301  includes a first flange  303  and a second flange  304 , and an annular groove  305  is formed between the first flange  303  and the second flange  304 . A seal ring  311  is attached to the annular groove  305 , and a space between an inner periphery of the cylinder  200  and an outer periphery of the piston  301  is sealed by the seal ring  311 . 
     Referring also to  FIG. 3 , a cutout recess portion  312  is formed in the annular groove  305 , and when the seal ring  311  moves to the first flange  303  side, the entire space between the inner periphery of the cylinder  200  and the outer periphery of the piston  301  is sealed, and when the seal ring  311  moves to the second flange  304  side, a gap is formed at the cutout recess portion  312 , such that air in the cylinder  200  leaks. A columnar portion  309  for preventing the seal ring  311  from coming off is formed in the cutout recess portion  312 . 
     The rod  302  includes a plate portion  306  extending from a back surface side of the second flange  304  of the piston  301 , a pair of parallel reinforcing ribs  307  formed on both surfaces of the plate portion  306 , and an attachment hole  308  formed in a protruding side end portion of the plate portion  306 . The attachment hole  308  is used for attachment to the other side of the opening and closing member such as a glove box. In this case, the attachment hole  308  is attached so as to be rotatable about an axis of the attachment hole  308 . 
     A plurality of stopper portions  313  are formed on a surface of the second flange  304  opposite to the annular groove  305 . When the piston rod  300  is pulled out to the maximum extent, the stopper portions  313  come into contact with an end surface  413  on a protruding side of a cylindrical portion  410  of the cap  400  shown in  FIG. 4 , and regulate further pulling out of the piston rod  300 . 
     Further, on both sides of the columnar portion  309 , ribs are formed by further increasing a diameter of a connection portion between the reinforcing rib  307  and the second flange  304  in two stages so as to protrude, and the diameter-increased portion provided continuously with the second flange  304  constitutes a part of the stopper portion  313 . Further, the lower diameter-increased portion slightly away from the second flange  304  is disposed inside an engagement claw  408  of the cap  400 , which will be described later, and forms the deflection regulating portion  310  that prevents inward deflection of the engagement claw  408 . In this embodiment, the deflection regulating portion  310  is formed by four ribs protruding parallel to each other at predetermined intervals on both surfaces of the plate portion  306 . 
     Referring also to  FIGS. 1 and 4 , the cap  400  includes an end plate  401  that closes the opening end portion  203  of the cylinder  200 . An insertion hole  402  through which the rod  302  of the piston rod  300  is inserted and extracted is provided in a central portion of the end plate  401 . The insertion hole  402  has an elongated slit shape as a whole, and has diameter-increased hole portions  403  extending in the vicinity of both end portions of the insertion hole  402  so as to intersect with each other. The diameter-increased hole portions  403  are portions through which the reinforcing rib  307  of the rod  302  passes. On an inner surface side of the end plate  401 , a pair of arc-shaped ribs  404  disposed so as to face each other with the insertion hole  402  interposed therebetween, and a pair of parallel guide ribs  405  extending from an inner side of each arc-shaped rib  404  toward the insertion hole  402  are provided. The guide ribs  405  are in contact with both surfaces of the plate portion  306  and contribute to guiding the slide of the rod  302 . 
     For the same purpose, on a front surface side of the end plate  401 , a pair of guide pieces  411 , which are erected along a longitudinal direction of the insertion hole  402  and disposed so as to face each other with the insertion hole  402  interposed therebetween, and a pair of guide pieces  412 , which are erected on both end portions in the longitudinal direction of the insertion hole  402  and similarly disposed so as to face each other with the insertion hole  402  interposed therebetween, are provided. The guide pieces  411  and  412  also contribute to guiding the slide of the rod  302 . 
     Further, the cylindrical portion  410  having an outer diameter adapted to an inner periphery of the cylinder  200  is formed on the inner surface side of the end plate  401 . When the rod  302  of the piston rod  300  is pulled out, the stopper portion  313  of the piston rod  300  comes into contact with the end surface  413  of the cylindrical portion  410 , and further pulling out of the rod  302  is regulated. The engagement claws  408  that are deflectable via slits  407  are formed at a plurality of positions in a peripheral direction of the cylindrical portion  410 , that is, at four positions in this embodiment. The engagement claw  408  has a tapered surface whose thickness gradually increases toward a base portion side in an insertion direction into the cylinder  200 , and a back surface side thereof is engaged with the engagement hole  204  of the cylinder  200  such that the cap  400  is prevented from coming off. Further, a protrusion portion  406  is formed at a portion of the cylindrical portion  410  facing in the radial direction, and the protrusion portion  406  is fitted into the cutout portion  205  of the cylinder  200  to position the cap  400  in a rotation direction. Then, by fitting the protrusion portion  406  into the cutout portion  205 , the engagement claw  408  is aligned and engaged with the engagement hole  204 . 
     By the way, the rod  302  is rotatably attached to the other side of the opening and closing member such as a glove box via the attachment hole  308 . Referring also to  FIG. 5 , the rotation axis is in a direction of an arrow A in  FIG. 5 . Then, aback surface of the engagement claw  408  forms an inclined surface  409  inclined with respect to the rotation axis A when viewed in a direction of an axis C of the cylinder  200 . Further, the inclined surface  40 ) is disposed so as to face the axial C side of the cylinder  200 . Further, a plurality of, four in this embodiment, the inclined surfaces  409  are disposed so as to be line-symmetrical with respect to a line passing through the rotation axis A and a line B orthogonal to the rotation axis A and passing through the axis C of the cylinder  200 . Then, front end portions of the deflection regulating portions  310  of the piston rod  300  are respectively disposed in the vicinity of the inclined surfaces  409  on the inner sides of the engagement claws  408 . In this embodiment, the inclined surface  409  serves as a contact surface of the present invention. The inclined surface  409  may be a flat surface or a concave curved surface as long as the inclined surface  409  is inclined with respect to the rotation axis A. Further, the contact surface formed on the back surface of the engagement claw  408  is not limited to the inclined surface  409  as described above, may have any shape as long as the deflection regulating portion  310  can come into contact with the contact surface when the rod  302  swings, and may be, for example, a surface having an L-shaped cross section formed by a surface perpendicular to the rotation axis A and a surface perpendicular to the line B. 
     Next, an operation of the air damper  100  will be described. 
     The air damper  100  is attached to an opening and closing member such as a glove box, and is used to apply a braking force to the opening and closing member when the opening and closing member is opened, for example. In this case, the bracket  206  of the cylinder  200  is rotatably attached to one side of the opening and closing member via the attachment hole  207 , and the end portion on the protruding side of the rod  302  of the piston rod  300  is rotatably attached to the other side of the opening and closing member via the attachment hole  308 . 
     Then, when the opening and closing member is opened, the rod  302  is pulled out from the cylinder  200 , and the piston  301  slides in the cylinder  200  toward the cap  400 . At this time, the seal ring  311  moves to an inner surface side of the first flange  303  (see  FIG. 3 ), and hermetically seals a space between the outer periphery of the piston  301  and the inner periphery of the cylinder  200 , and therefore, the inside of the cylinder  200  becomes a negative pressure, and a braking force is applied. On the other hand, when the opening and closing member is closed, the rod  302  is pushed into the cylinder  200 , and the piston  301  moves to the closing end portion  202  side. At this time, the seal ring  311  moves to the second flange  304  side, and a gap is formed by the cutout recess portion  312 , and therefore, air in the cylinder  200  flows out through the gap, and the braking force is released. Therefore, since the opening and closing member is slowly opened when being opened, it is possible to prevent the opening and closing member from being vigorously opened to scatter the content, and it is possible to quickly close the opening and closing member when being closed. 
     On the other hand, for maintenance, repair, and the like of the vehicle, it may be necessary to remove the opening and closing member such as a glove box or to open the opening and closing member largely. In such a case, it may be necessary to remove the air damper  100  and the like attached to the opening and closing member or to largely pull out the rod  302 , and the rod  302  of the piston rod  300  may largely swing with respect to the cylinder  200  in accordance with such an operation. 
     However, according to the air damper  100 , as shown in  FIG. 6 , when the rod  302  swings, for example, in the direction of the rotation axis A, the deflection regulating portion  310  comes into contact with the inclined surface  409  of the engagement claw  408  positioned on the upper side or the lower side in  FIG. 6  (the upper side in the example of  FIG. 6 ), and it is possible to prevent the engagement claw  408  from coming off the engagement hole  204  of the cylinder  200 . Further, as shown in  FIG. 7 , when the rod  302  swings, for example, in a direction B perpendicular to the rotation axis A, the deflection regulating portion  310  comes into contact with the inclined surface  409  of the engagement claw  408  positioned on the left side or the right side in  FIG. 7  (the left side in the example of  FIG. 7 ), and it is possible to prevent the engagement claw  408  from coming off the engagement hole  204  of the cylinder  200 . When the rod  302  swings obliquely, the deflection regulating portion  310  positioned in that direction comes into contact with the back surface of the engagement claw  408  positioned in that direction, and it is possible to prevent the engagement claw  408  from coming off the engagement hole  204  of the cylinder  200 . Accordingly, regardless of the direction in which the rod  302  swings, the deflection regulating portion  310  comes into contact with the inclined surface  409  on the inner surface side of the engagement claw  408 , and the engagement claw  408  is prevented from coming off the engagement hole  204 , and therefore, it is possible to effectively prevent the cap  400  from coming off the cylinder  200 . 
     Further, as shown in  FIGS. 5 to 7 , in this embodiment, four or more, four in this embodiment, the engagement claws  408  are formed so as to be line-symmetrical with respect to the line passing through the rotation axis A and the line B orthogonal to the rotation axis A when viewed in the direction of the axis C of the cylinder  200 . Therefore, regardless of the direction in which the rod  302  swings with respect to the cylinder  200 , the deflection regulating portion  310  prevents the engagement claws  408  from coming off in a well-balanced manner, and the cap  400  can be more effectively prevented from coming off the cylinder  200 . 
     Further, as shown in  FIGS. 5 to 7 , in this embodiment, the inclined surface  409  on the inner surface side of the engagement claw  408  is formed so as to face the axial C side when viewed in the direction of the axial C of the cylinder  200 . Therefore, when the rod  302  swings in the direction of the rotation axis A, the deflection regulating portions  310  come into contact with the inclined surfaces  409  of the two left and right engagement claws  408  disposed on the upper side or the lower side in  FIG. 6  (the upper side in the example of  FIG. 6 ), and the engagement claws  408  are pressed so as to be separated from each other in the left and right direction. Similarly, when the rod  302  swings in a direction along the line B orthogonal to the rotation axis A, the deflection regulating portions  310  come into contact with the two upper and lower engagement claws  408  disposed on the left side or the right side in  FIG. 7  (the left side in the example of  FIG. 7 ), and the engagement claws  408  are pressed so as to be separated from each other in the upper and lower direction. As a result, the effect of pushing the engagement claw  408  into the engagement hole  204  can be improved, and the cap  400  can be more effectively prevented from coming off the cylinder  200 . 
     REFERENCE SIGNS LIST 
     
         
         
           
               100 : air damper 
               200 : cylinder 
               201 : cylinder body 
               202 : closing end portion 
               203 : opening end portion 
               204 : engagement hole 
               205 : cutout portion 
               206 : bracket 
               207 : attachment hole 
               300 : piston rod 
               301 : piston 
               302 : rod 
               308 : attachment hole 
               309 : columnar portion 
               310 : deflection regulating portion 
               311 : seal ring 
               313 : stopper portion 
               400 : cap 
               402 : insertion hole 
               408 : engagement claw 
               409 : inclined surface