Patent Publication Number: US-9850975-B2

Title: Damper

Description:
FIELD OF TECHNOLOGY 
     The present invention relates to an improvement of a damper generating a braking force by an operation of a piston. 
     BACKGROUND ART 
     There is an air damper proposed to obtain a large output with a compact size, and comprising a cylinder main member provided with two cylinder portions in juxtaposition; and a piston main member formed by a piston rod moving inside the two cylinder portions respectively (see Patent Document 1). 
     The air damper of the Patent Document 1 covers the whole braking force by a resistance due to a pressure change. In such a case, when the piston rod starts to move, the braking force is small, and when the operation advances, the braking force rapidly increases. Consequently, in such a method, in some cases, there may be caused situations wherein a braking object halts in a process of a movement, and moreover, starts to unexpectedly move backward toward a position before the movement from a middle of the movement so as to be difficult to properly control the movement of the aforementioned braking object in a whole process thereof. Also, in the air damper of the Patent Document 1, the braking force thereof depends on a cross-sectional area of the cylinder main member so as to have a limit for reducing a size thereof. 
     PRIOR ART DOCUMENT 
     Patent Document 
     Patent Document 1: Japanese Patent No. 3298002 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     A main object of the present invention is to provide a damper which can properly control a movement of a braking object in a whole process thereof, and is suitable for reducing a size and thickness. 
     Means for Solving the Problems 
     In order to obtain the aforementioned object, in the first aspect of the present invention, a damper comprises a piston provided with a rod; and a housing storing the piston, and generates a braking force by an operation of the piston. The aforementioned piston is provided with a seal member relative to an inner wall of the housing; and a slider provided slidably relative to the piston, and contacting the inner wall of the housing with a predetermined frictional force, and when the braking force is generated, the slider presses against the seal member, and a portion contacting the inner wall of the housing in the seal member deforms outwardly toward the housing. 
     According to such a structure, a resistance due to a pressure changes by the operation of the piston, and a frictional resistance between the seal member and the housing generated by deforming the seal member by the slider as described above, can generate an intended braking force. 
     In one of preferred aspects of the present invention, the slider contacts the inner wall of the housing with a lip. Also, one of the preferred aspects of the present invention is that the slider is provided with a pressure contact portion pressed against the seal member from the rod side. Also, one of the preferred aspects of the present invention is that in accordance with an operation speed of the piston, a deformation amount of the seal member increases. Also, one of the preferred aspects of the present invention is that in accordance with the operation speed of the piston, a sliding amount of the slider increases. 
     Also, in order to obtain the aforementioned object, in the present invention from a second viewpoint, a damper comprises a piston provided with a rod; and a housing storing the piston, and generates a braking force by an operation of the piston. The piston is provided with a seal member relative to an inner wall of the housing, and a portion contacting the inner wall of the housing in the seal member deforms outwardly toward the housing when a chamber formed between the piston and a blocking end of the housing has a negative pressure. 
     According to such a structure, the resistance due to the pressure change by the operation of the piston, and the frictional resistance between the seal member and the housing generated by deforming the portion contacting the inner wall of the housing in the seal member as described above, can generate the intended braking force. In that case, furthermore, one of the preferred aspects is that in accordance with the operation speed of the piston, the deformation amount of the seal member increases. 
     Also, one of the preferred aspects of the present invention is that an outer frame shape in a cross section of the housing in a direction orthogonal to a moving direction of the piston forming each damper device described above is made flat. 
     Effect of the Invention 
     The damper according to the present invention can properly control a movement of an object to be braked in a whole process thereof, and is suitable for reducing a size and thickness as well. Also, the braking force of the damper according to the present invention is caused by a deformation of the seal member so as to simplify a structure thereof, and the damper according to the present invention includes a characteristic which can generate the intended braking force without paying any special attention to a size accuracy of each part of the structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a damper (a first example) according to one embodiment of the present invention. 
         FIG. 2  is a cross-sectional structural view of the aforementioned first example. 
         FIG. 3  is an enlarged cross-sectional structural view of essential parts of the first example, and shows a state when a piston moves forward. 
         FIG. 4  is an enlarged cross-sectional structural view of the essential parts of the first example, and shows a state when the piston moves forward. 
         FIG. 5  is an enlarged cross-sectional structural view of the essential parts of the first example, and shows a state when the piston moves backward. 
         FIG. 6  is an exploded perspective view of the first example. 
         FIG. 7  is a perspective view of a head part forming the piston of the first example. 
         FIG. 8  is a perspective view of the piston of the first example. 
         FIG. 9  is a perspective view of the piston of the first example, and shows such piston viewed from a right side in  FIG. 8 . 
         FIG. 10  is a cross-sectional view of the damper (a second example) according to another embodiment of the present invention. 
         FIG. 11  is an exploded perspective view of the aforementioned second example. 
         FIG. 12  is a perspective view of parts forming the piston of the second example. 
         FIG. 13  is an enlarged cross-sectional structural view of the essential parts of the damper (a third example) according to another embodiment of the present invention, and shows a state when the piston moves forward. 
         FIG. 14  is an enlarged cross-sectional structural view of the essential parts of the third example, and shows a state when the piston moves backward. 
     
    
    
     BEST MODES OF CARRYING OUT THE INVENTION 
     Hereinafter, based on  FIG. 1  to  FIG. 14 , typical embodiments of the present invention will be explained. A damper according to the embodiments generates a braking force for an operation of a piston P forming the damper, i.e. a movement or a relative movement of such piston P. Typically, the damper is combined with an article provided with a movable portion or the like (omitted in the drawings) which becomes an object to be braked, and used for applying the braking force relative to a movement of such object so as to move such object slowly and properly, with a feeling of a high quality, or prevent such braking object from moving extraordinarily. 
     Such damper comprises the piston P provided with a rod  1 ; and a housing H storing the piston P. Typically, such damper directly or indirectly links either one of the rod  1  or the housing H on the aforementioned braking object side, and directly or indirectly links the other of the rod  1  or the housing H on a side movably supporting such braking object so as to be combined with the article provided with such braking object. 
     The aforementioned housing H has a cylindrical shape opening one end and closing the other end. In illustrated examples, such housing H has a flat cylindrical shape wherein a thickness thereof is made notably small. More specifically, in the illustrated examples, in such housing H, a cross section orthogonal to a cylinder shaft thereof has substantially a rectangular shape. Side walls  8  forming a thickness side of the housing H have a shape with a curvature wherein the outside of the housing H becomes the outside of the curvature. Outside a blocking end  9  of the housing H, there is formed a bracket portion  10  for the aforementioned linking. 
     The aforementioned rod  1  has a long rod shape in a moving direction of the piston P. On one end positioned outside the housing H in the rod  1 , there is formed a bracket portion  1   a  for the aforementioned linking. 
     The aforementioned piston P is provided with a seal member  2  relative to an inner wall of the housing H; and a slider  3  provided slidably relative to the piston P, and contacting the inner wall of the housing H with a predetermined frictional force. 
     In the illustrated examples, the piston P is provided with a first flange  4  facing the blocking end  9  of the housing H; and a second flange  5  retaining the seal member  2  and the slider  3  between the second flange  5  and the first flange  4 . The second flange  5  is positioned at a back side of the first flange  4 , i.e. on an open end  12  side of the housing H. In both the first flange  4  and the second flange  5 , an outer frame shape in a cross section in a moving direction x (see  FIG. 2 ) of the piston P, i.e. in a direction orthogonally in a direction along the cylinder shaft of the housing H, has a shape which becomes a complementary shape to an inner frame shape in the cross section of the housing H in the same direction. Thereby, the piston P is guided by the inner wall of the housing H so as to reciprocate in the direction along the cylinder shaft of the housing H. 
     In the first example shown in  FIG. 1  to  FIG. 9 , the second flange  5  is formed in the other end of the rod  1 . The first flange  4  is formed in a head part  6  which is a separate member from the rod  1  (see  FIGS. 6 and 7 ). The head part  6  includes a plate-like trunk portion  6   a  facing a plate face to the side walls on a width side of the housing H. On a side facing the blocking end  9  of the housing H in the trunk portion  6   a , there is integrally formed the first flange  4  positioning a flange end outwardly more than an outer face of the trunk portion  6   a  at each position around the trunk portion  6   a . Also, in a portion which is an end portion facing the open end  12  of the housing H in the trunk portion  6   a , and positioned on the cylinder shaft of such housing H, there is formed a male joint portion  6   b  formed by a head portion  6   c  and a neck portion  6   d,  and integrated with the trunk portion  6   a  through the neck portion  6   d . In a portion positioned on the cylinder shaft of the housing H in the second flange  5 , there are formed a female joint portion  5   a  formed by a first concave portion  5   b  receiving and retaining the head portion  6   c  of the male joint portion  6   b;  and a second concave portion  5   c  receiving and retaining the neck portion  6   c  of the male joint portion  6   b , and opening outwardly at an end portion facing the blocking end  9  of the housing H in the second flange  5  (see  FIG. 6 ). In the first example, from a state wherein the seal member  2  and the slider  3  respectively having a flat ring shape are combined with the head part  6  in such a way as to surround the trunk portion  6   a  of the head part  6 , the male joint portion  6   b  of the head part is fitted into the female joint portion  5   a  of the second flange  5  so as to form the piston P formed by retaining the seal member  2  and the slider  3  between such first flange  4  and second flange  5 . Incidentally, the reference symbol  6   e  shown in  FIG. 5  represents a cut-out portion inside the head part  6 . 
     Typically, the seal member  2  is formed by rubber or plastic having a rubber-like elasticity, and has the flat ring shape. The truck portion  6   a  of the head part  6  is inserted to pass through the inside of the seal member  2  from a side of the male joint portion  6   b  so that such head part  6  and seal member  2  are combined. In the illustrated examples, the seal member  2  includes a front end face  2   a  relative to the first flange  4 ; an inner face  2   b  relative to an outer face of the head part  6 ; and an outer face  2   c  relative to the inner wall of the housing H (see  FIG. 3 ). Also, on a side facing the open end  12  side of the housing H in the seal member  2 , there is formed a circumferential groove  2   d  between the inner face  2   b  and the outer face  2   c . An outer face side sandwiching the circumferential groove  2   d  extends toward the open end  12  side of the housing H throughout all circumferential directions of the seal member  2 , so that the seal member  2  is provided with a skirt-shaped portion  2   e , and the outer face  2   c  of the seal member  2  increases a size more than the inner face  2   b  in the moving direction x of the piston P. The outer face  2   c  of the seal member  2  inclines in a direction of gradually increasing a thickness of the seal member  2  as moving from the front end face  2   a  to a terminal  2   f  of the skirt-shaped portion  2   e  (see  FIG. 4 ). Also, on the front end face  2   a  of the seal member  2 , there is formed a circumferential projection piece  2   g.    
     Typically, the slider  3  is formed by the plastic, and has the flat ring shape. As mentioned above, from a state wherein the head part  6  and the seal member  2  are combined, the trunk portion  6   a  of the head part  6  is inserted to pass through the inside of the slider  3  from the side of the male joint portion  6   b , so that such head part  6  and slider  3  are combined. In the illustrated examples, the slider  3  is provided with a short cylindrical base  3   a  wherein an inner frame shape in a cross section orthogonally in the moving direction x of the piston P has a shape which becomes complementary to an outer frame shape in a cross section of the trunk portion  6   a  of the head part  6  in the same direction; and a lip  3   d  integrally formed outside the base  3   a  (see  FIG. 3 ). In the illustrated examples, the lip  3   d  has a circumferential fin-like member formed in such a way as to surround the base  3   a . The lip  3   d  has a base portion  3   e  integrated with an outer face portion of the base  3   a  between a front end  3   b  positioned on a seal member  2  side and a back end  3   c  positioned on the open end  12  side of the housing H in the base  3   a , and is provided with an extension portion  3   f  extending toward the open end  12  side of the housing H from the base portion  3   e  (see  FIG. 4 ). A shoulder portion  3   h  is formed between the base portion  3   e  and the extension portion  3   f . The extension portion  3   f  has inclination gradually increasing a distance between the extension portion  3   f  and the base  3   a  as moving to a terminal  3   g  thereof from the shoulder portion  3   h.    
     The seal member  2  and the slider  3  are held between the first flange  4  and the second flange  5  in a state allowing a slight movement along the moving direction x of the piston P. The outer face  2   c  of the seal member  2  contacts the inner wall of the housing H throughout a whole circumference thereof, and the extension portion  3   f  of the slider  3  contacts the inner wall of the housing H on a terminal  3   g  side thereof throughout a whole circumference thereof as well. Also, a portion located between the front end  3   b  of the base  3   a  of the slider  3  and the base portion  3   e  of the lip  3   d  is positioned inside the skirt-shaped portion  2   e  of the seal member  2 , and the shoulder portion  3   h  of the lip  3   d  of the slider  3  faces the terminal  2   f  of the skirt-shaped portion  2   e  of the seal member  2  ( FIG. 2  to  FIG. 5 ). 
     Then, in the present embodiments, when the braking force is generated, the slider  3  presses the seal member  2 , and a portion contacting the inner wall of the housing H in the seal member  2  deforms outwardly toward the housing H. 
     In the illustrated examples, when the piston P moves forward in a direction of separating from the blocking end  9  of the housing H, a chamber C formed between the piston P and the blocking end  9  comes to have a negative pressure, thereby generating a resistance due to a pressure change which becomes one portion of the braking force ( FIG. 3  and  FIG. 4 ). Also, at that time, the slider  3  deforms the seal member  2  as mentioned above to increase a frictional force between the seal member  2  and the housing H, thereby generating a frictional resistance which becomes one portion of the braking force ( FIG. 3  and  FIG. 4 ). 
     In the illustrated examples, when the piston P moves forward, the slider  3  becomes difficult to move in the forward-moving direction due to a shape of the lip  3   d , so that the shoulder portion  3   h  of the slider  3  is pressed against the terminal  2   f  of the skirt-shaped portion  2   e  of the seal member  2 , and the circumferential projection piece  2   g  formed in the front end face  2   a  of the seal member  2  is firmly attached to the first flange  4  so as to seal between the front end face  2   a  and the first flange  4 , and the skirt-shaped portion  2   e  deforms outwardly so as to seal between the outer face  2   c  of the seal member  2  and the inner wall of the housing H ( FIG. 3  and  FIG. 4 ). Thereby, in the illustrated examples, when the piston P moves forward, ventilation relative to the chamber C is limited to a vent passage formed by a groove  7  (see  FIG. 6  to  FIG. 8 ) formed throughout the end portion facing the open end  12  of the housing H in the trunk portion  6   a  from an edge portion of the first flange  4  in a portion positioned on the cylinder shaft of the housing H in the head part  6  forming the piston P so as to generate the resistance due to the aforementioned pressure change. Also, the skirt-shaped portion  2   e  of the seal member  2  deforms outwardly as described above so as to generate the aforementioned frictional resistance. Namely, the slider  3  is provided with a pressure contact portion pressed against the seal member  2  from the rod  1  side, and in the illustrated examples, the shoulder portion  3   h  functions as the pressure contact portion. 
     In the present embodiments, in accordance with an operation speed of the piston P, a deformation amount of the seal member  2  increases. From another point of view, in accordance with the operation speed of the piston P, a sliding amount of the slider  3  increases. Therefore, the damper according to the embodiments is a damper with a speed response type changing the braking force in accordance with a moving speed of the braking object which becomes the braking object, or a load response type. 
     When all or most of the braking force is covered by the resistance due to the aforementioned pressure change, the braking force is small at the time of starting the piston operation, and when the operation of the piston advances, the braking force rapidly increases. Consequently, in such a method, in some cases, there may be caused situations wherein the braking object halts in a moving process, and moreover, starts to unexpectedly move backward toward a position before the movement from a middle of the movement so as to be difficult to properly control the movement of the aforementioned braking object in a whole process thereof. 
     On the other hand, in the damper according to the embodiments, the braking force is covered by the resistance due to the pressure change and the frictional resistance so as to properly control the movement of the braking object in the whole process thereof. Namely, the damper according to the embodiments can prevent the situations wherein the braking object halts in a forward moving process, and moreover, starts to unexpectedly move backward toward the position before the forward movement from a middle of the forward movement as much as possible. Also, the damper according to the embodiments can easily generate an intended braking force even if a cross-sectional area of the housing H is made small so as to have a characteristic which can easily reduce a size and thickness. 
     On the other hand, in the illustrated examples, when the piston P moves backward in a direction of approaching the blocking end  9  of the housing H, the chamber C is difficult to have a positive pressure, and at that time, the aforementioned frictional resistance becomes small as well ( FIG. 5 ). In the illustrated examples, when the piston P moves backward, the seal member  2  and the slider  3  move to a second flange  5  side to form a gap y between the first flange  4  and the front end face  2   a  of the seal member  2 , and due to the shape of the lip  3   d , the slider  3  can easily move in a backward-moving direction of the piston P, so that the slider  3  is not pressed against the seal member  2 , and the frictional resistance between the seal member  2  and the inner wall of the housing H does not increase as well. In addition to the vent passage formed by the groove  7 , the chamber C is communicated through the gap y between the first flange  4  and the front end face  2   a  of the seal member  2  as well. Also, in the illustrated examples, on the outer face of the seal member  2 , there is formed a groove  2   h  along the moving direction x of the piston P, and the groove  2   h  opens a groove end on a chamber C side, and closes a groove end on the open end  12  side of the housing H; however, when the piston P moves backward, due to a pressure increase on the chamber C side, at a position forming the groove  2   h , one portion of the seal member  2  deforms inwardly, and exhaust ventilation can be carried out from the chamber C through the groove  2   h  as well. Thereby, in the illustrated examples, when the piston P moves backward, the damper is made so as not to generate a special braking force. Also, since the vent passage of the chamber C is expanded simultaneously when the piston P starts to move backward so as to prevent a situation wherein the braking object moves backward toward the position before the forward movement from the middle of the forward movement. 
     In the damper of a second example shown in  FIG. 10  to  FIG. 12 , thicknesses of the housing H and piston P are increased compared to the damper of the first example. The reference numeral  13  in the drawings represents a head corresponding to the head part  6  of the first example, and the head is integrated with the rod  1 . The reference numeral  14  in the drawings represents claw portions functioning in the same manner as in the second flange  5  of the first example, and the reference numeral  15  represents a cap closing the open end  12  of the housing H. Also, in the damper of the second example, the vent passage always communicating the chamber C with the outside becomes an orifice  16  penetrating the head. The rest of the structural parts of the damper of the second example are substantially the same as those of the damper of the first example, so that regarding the same structural parts, symbols same as those used in  FIG. 1  to  FIG. 9  showing the damper of the first example are assigned to  FIG. 10  to  FIG. 12  showing the damper of the second example, and their explanations are omitted. 
     The damper of a third example shown in  FIG. 13  and  FIG. 14  has a structure that the piston P is not provided with the slider  3 . The rest of the structures of the damper of the third example are substantially the same as those of the damper of the first example so as to omit their explanations. Then, in the damper of the third example, the portion contacting the inner wall of the housing H in the seal member  2  deforms outwardly toward the housing H when the chamber C formed between the piston P and the blocking end  9  of the housing H has the negative pressure ( FIG. 13 ). Namely, in the third example, when the piston P moves forward, the circumferential projection piece  2   g  formed on the front end face  2   a  of the seal member  2  is firmly attached to the first flange  4  so as to seal between the front end face  2   a  and the first flange  4 , and since the inside of the chamber C has the negative pressure, due to a force applied to the skirt-shaped portion  2   e  and shown with the reference alphabet F in  FIG. 13 , the skirt-shaped portion  2   e  deforms outwardly to seal between the outer face  2   c  of the seal member  2  and the inner wall of the housing H ( FIG. 13 ). Thereby, in the third example, when the piston P moves forward, the resistance due to the pressure change is generated. Also, the skirt-shaped portion  2   e  of the seal member  2  deforms outwardly so as to generate the frictional resistance. Even in the damper of the third example, in accordance with the operation speed of the piston P, the deformation amount of the seal member  2  increases. 
     All of each damper device explained above can easily generate the intended braking force even if the cross-sectional area of the housing H is made small as described above so as to have the flat and thin outer frame shape in the cross section of the housing in the direction orthogonally in the moving direction of the piston. 
     Incidentally, obviously, the present invention is not limited to the embodiments explained above, and the embodiments include all embodiments which can obtain the object of the present invention. 
     All contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2013-262149 filed on Dec. 19, 2013 are cited in their entireties herein and are incorporated as a disclosure of the specification of the present invention.