Patent Publication Number: US-10320130-B2

Title: Barrel terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This non-provisional application claims priority to and benefit of, under 35 U.S.C. § 119(a), Patent Application No. 201720114080.2 filed in P.R. China on Jan. 20, 2017, the entire content of which is hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The present invention relates generally to a barrel terminal, and more particularly to a barrel terminal that is capable of absorbing deformation stress. 
     BACKGROUND OF THE INVENTION 
     It is known that a barrel terminal capable of allowing a large current to pass through has a contact portion and a connecting portion which are interconnected. The contact portion has multiple fence-shaped elastic pieces distributed circumferentially. A mating member is inserted into the barrel terminal in parallel from one side of the barrel terminal and elastically contacts the elastic pieces of the contact portion. A cable is inserted into the barrel terminal from the other side of the barrel terminal. The tube wall of the connecting portion covers the cable, and the cable and the connecting portion can be fixedly connected with each other in a riveting manner or in a soldering manner, so that the electric connection between the mating member and the cable is realized by means of the transmission of the barrel terminal. 
     Although the design that the contact portion has multiple elastic pieces can meet the requirements on the electric conductivity and heat dissipation performance of the terminal, the elastic pieces are very likely to deform. When the connecting portion and the cable are riveted or soldered, the connecting portion is deformed to generate the deformation stress, the surplus stress is transferred from the connecting portion to the contact portion, the structure of the elastic pieces is deformed, resulting in the reduction of a contact area between the elastic pieces and the mating member and the reduction of a clamping force of the elastic pieces to the mating member, so that the elastic contact between the elastic pieces and the mating member is unstable. 
     Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies. 
     SUMMARY OF THE INVENTION 
     In one aspect, the present invention relates to a large-current barrel terminal that achieves objectives of absorbing the deformation stress of a connecting portion by means of a buffer portion and protecting a contact portion against the damage of the deformation stress. 
     In certain embodiments, a barrel terminal has one end for a mating member to be inserted therein and the other end for electrical connection with a cable. The barrel terminal includes a contact portion, a connecting portion and a buffer portion. The contact portion has multiple contact elastic pieces, and each contact elastic piece has elasticity and is used for electrically contacting the mating member. The connecting portion is used to connect the cable. The buffer portion connects the contact portion and the connecting portion. The buffering portion has multiple absorption portions, and the absorption portions absorb the deformation stress of the connecting portion. 
     In certain embodiments, the multiple absorption portions are longitudinally arranged at intervals and uniformly distributed. 
     In certain embodiments, the absorption portions are of elastic piece structures. 
     In certain embodiments, the multiple absorption portions are encircled to form a buffer cavity. 
     In certain embodiments, the buffer cavity has a central axis, and a distance from each of the absorption portions to the central axis is equal. 
     In certain embodiments, the buffer cavity has a central axis, and the distance from each of the absorption portions to the central axis is gradually reduced along an insertion direction of the mating member. 
     In certain embodiments, the multiple contact elastic pieces are encircled to form a contact cavity, the contact cavity is communicated with the buffer cavity, and the contact cavity is used for the mating member to be inserted therein. 
     In certain embodiments, the connecting portion has a connection cavity, the connection cavity is used for the cable to enter, and the connection cavity, the buffer cavity and the contact cavity are communicated with one another. 
     In certain embodiments, the connection cavity has a first cavity and a second cavity which are communicated with each other, the first cavity is disposed between the buffer cavity and the second cavity, and the buffer cavity, the first cavity and the second cavity are communicated with one another. 
     In certain embodiments, a diameter of the first cavity is identical to a minimum diameter of the buffer cavity, and the diameter of the first cavity is smaller than a diameter of the second cavity. 
     In certain embodiments, the cable is fixedly connected with the connecting portion in a riveting manner or soldering manner. 
     Compared with the related art, one end of the barrel terminal is used for inserting an mating member, the other end is used for connecting a cable, and the barrel terminal includes a contact portion, a connecting portion, and a buffer portion. The contact portion has multiple contact elastic pieces, and the contact elastic pieces are used for electrically contacting the mating member. The connecting portion is used for connecting the cable. The buffer portion connects the contact portion and the connecting portion. The buffer portion has multiple absorption portions, the absorption portions absorb the deformation stress of the connecting portion to prevent the stress from being transferred to the contact portion and to avoid the deformation of the contact elastic pieces, so as not to cause the reduction of the contact area between the contact elastic pieces and the mating terminal, thereby further preventing the deformation from causing the reduction of a clamping force of the barrel terminal to the mating member and from causing the unstable electrical connection of the barrel terminal and the mating member and the poor electric conductivity. 
     These and other aspects of the present invention will become apparent from the following description of the preferred embodiment taken in conjunction with the following drawings, although variations and modifications therein may be effected without departing from the spirit and scope of the novel concepts of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate one or more embodiments of the invention and together with the written description, serve to explain the principles of the invention. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment. 
         FIG. 1  is a schematic three-dimensional view illustrating molding steps of a barrel terminal according to a first embodiment of the present invention. 
         FIG. 2  is a sectional plane view of  FIG. 1  before the barrel terminal is fixedly connected with a cable. 
         FIG. 3  is a sectional plane view of  FIG. 1  after the barrel terminal is fixedly connected with the cable. 
         FIG. 4  is a schematic three-dimensional view of  FIG. 1  after the barrel terminal is connected with the cable and not engaged with a mating member. 
         FIG. 5  is a schematic three-dimensional cross-sectional view of  FIG. 1  after the barrel terminal is connected with the cable and not cooperated with the mating member. 
         FIG. 6  is a schematic three-dimensional cross-sectional view of  FIG. 1  after the barrel terminal is connected with the cable and engaged with the mating member. 
         FIG. 7  is a schematic three-dimensional view illustrating molding steps of a barrel terminal according to a second embodiment of the present invention. 
         FIG. 8  is a schematic three-dimensional view of a barrel terminal according to a third embodiment of the present invention. 
         FIG. 9  is a schematic three-dimensional view illustrating the engagement of the barrel terminal and the cable in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. Various embodiments of the invention are now described in detail. Referring to the drawings, like numbers indicate like components throughout the views. As used in the description herein and throughout the claims that follow, the meaning of “a”, “an”, and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. Moreover, titles or subtitles may be used in the specification for the convenience of a reader, which shall have no influence on the scope of the present invention. 
     It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element&#39;s relationship to another element as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements. The exemplary term “lower”, can therefore, encompasses both an orientation of “lower” and “upper,” depending of the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below. 
     As used herein, “around”, “about” or “approximately” shall generally mean within 20 percent, preferably within 10 percent, and more preferably within 5 percent of a given value or range. Numerical quantities given herein are approximate, meaning that the term “around”, “about” or “approximately” can be inferred if not expressly stated. 
     As used herein, the terms “comprising”, “including”, “carrying”, “having”, “containing”, “involving”, and the like are to be understood to be open-ended, i.e., to mean including but not limited to. 
     The description will be made as to the embodiments of the present invention in conjunction with the accompanying drawings in  FIGS. 1-8 . In accordance with the purposes of this invention, as embodied and broadly described herein, this invention, in one aspect, relates to a barrel terminal. 
       FIGS. 1-6  show a first embodiment of the present invention. Referring to  FIGS. 1, 2 and 4 , a barrel terminal  100  is formed by a cylindrical barrel with openings at two ends thereof. The barrel terminal  100  has a central axis X. As shown in step a of  FIG. 1 , one end of the barrel terminal  100  is used for an mating member  200  to be inserted therein, and the other end is connected with a cable  300 . The barrel terminal  100  includes a connecting portion  1  for connecting the cable  300 , a contact portion  3  for the mating member  200  to be inserted therein, and a buffer portion  2  connecting the connecting portion  1  and the contact portion  3 . 
     Referring to  FIGS. 1-3 , the connecting portion  1  has a tube wall  11 . The tube wall  11  is encircled along the central axis X to form a connection cavity  10 . The tail end of the tube wall  11  is radially expanded, as shown in step c of  FIG. 1 , so that the connection cavity  10  has a first cavity  101  and a second cavity  102  which are connected with each other. The first cavity  101  is disposed between the second cavity  102  and the buffer portion  2 . The buffer portion  2 , the first cavity  101  and the second cavity  102  are communicated with one another. A diameter D of the first cavity  101  is smaller than a diameter E of the second cavity  102 . The cable  300  is inserted into the connection cavity  10 . The cable  300  has an insulation portion  301  and a core portion  302 . The insulation portion  301  is correspondingly arranged at the first cavity  101 , and the core portion  302  is correspondingly arranged at the second cavity  102 . 
     Referring to  FIGS. 2-4 , the buffer portion  2  has multiple absorption portions  21 . The multiple absorption portions  21  are formed by cutting the cylindrical wall of the cylindrical barrel at intervals. As shown in step b of  FIG. 1 , in the present invention, the absorption portions  21  are of elastic piece structures. The absorption portions  21  are encircled along the central axis X to form a buffer cavity  20 . A diameter of the buffer cavity  20  is equal to the diameter D of the first cavity. The buffer cavity  20  is communicated with the connection cavity  10 , thus facilitating the heat dissipation of the barrel terminal  100 . The buffer cavity  20  supplies a buffer deformation space to the absorption portions  21 . When the connecting portion  1  is not deformed, the distance from each of the absorption portions  21  to the central axis X is equal, as shown in  FIG. 2 . After the connecting portion  1  is deformed, the distance from each of the absorption portions  21  to the central axis X is gradually reduced along the axial direction, as shown in  FIG. 3 . One end of each absorption portion  21  is connected with the connecting portion  1 , and the other end is connected with the contact portion  3 , so that the structure is compact, and the absorption portions  21  conveniently absorb the deformation stress of the connecting portion  1 . 
     Referring to  FIGS. 1, 5 and 6 , the contact portion  3  has a contact cavity  30  and multiple contact elastic pieces  31 . The multiple contact elastic pieces  31  are formed by cutting the tube wall of the cylindrical barrel at intervals. As shown in step b of  FIG. 1 , the multiple contact elastic pieces  31  are encircled along the central axis X to form the contact cavity  30 . The contact cavity  30  is communicated with the buffer cavity  20 , and the contact cavity  30  is communicated with the connection cavity  10  through the buffer cavity  20 , so that the heat dissipation performance of the barrel terminal  100  is good. Meanwhile, the contact elastic pieces  31  are twisted relative to the central axis X, so that the contact elastic pieces  31  incline along the central axis X, the middle positions of the contact elastic pieces  31  are arched toward the contact cavity  30  relative to two ends, and the contact elastic pieces  31  are arranged in an arc shape, as shown in step d of  FIG. 1 . The middle position of each contact elastic piece  31  is a contact point  310 . The mating member  200  is inserted into the contact cavity  30  in parallel from one side of the barrel terminal  100  and electrically contacts the contact point  310 . Multiple contact points  310  form multi-point contact with the mating member  200  to increase the contact area between the contact elastic pieces  31  and the mating member  200 , so that the electric contact between the barrel terminal  100  and the mating member  200  is good. Meanwhile, the contact elastic pieces  31  have a good clamping force to the mating member  200 , the electrical connection between the barrel terminal  100  and the mating member  200  is firm, and the electric contact is good. The contact portion  3  further has a front end ring  32  and a rear end ring  33 . The front end ring  32  and the rear end ring  33  are disposed at two ends of the contact elastic pieces  31  and surround the contact cavity  30  along the central axis X. The front end ring  32  is disposed at one end, which is close to the buffer portion  2 , of the contact elastic piece  31 , and the rear end ring  33  is disposed at one end, which is away from the buffer portion  2 , of the contact elastic piece  31 . An open end of the rear end ring  33  is radially expanded outward to form a flared opening  34 , as shown in step c of  FIG. 1 . The diameter d of the rear end ring  32  is smaller than the diameter e of the flared opening  34 , thereby playing a role in guiding the insertion of the mating member  200 , and further facilitating the insertion of the mating member  200 . 
     Referring to  FIGS. 2, 3 and 5 , the connecting portion  1  is fixedly connected with the cable  300  in a riveting manner. The cable  300  is inserted into the connection cavity  10 , and the tube wall  11  covers the cable  300 . When the tube wall  11  is compressed by using a crimping tool, the tube wall  11  is deformed toward the connection cavity  10 . The diameter of the first cavity is changed from D to D1, the diameter of the second cavity is changed from E to E1, where D1 is smaller than D, E1 is smaller than E, and D1 is smaller than E1. The tube wall  11  compresses the cable  300 , and the tube wall  11  is fixedly connected with the cable  300  in a crimping manner to form the electric connection. The tube wall  11  is deformed to generate deformation stress, the absorption portions  21  absorb the deformation stress of the tube wall  11  and are deformed toward the buffer cavity  20 . The closer the absorption portions  21  to the connecting portion  1 , the more deformation stress may be absorbed, the greater the deformation towards the buffer cavity  20  is, and the smaller the distance to the central axis X is, so that the distance from each of the absorption portions  21  to the central axis X is reduced along the insertion direction of the mating member  200 , the diameter of the buffer cavity  20  is reduced along the insertion direction of the mating member  200 , and the minimum diameter of the buffer cavity  20  is equal to the diameter D1 of the first cavity. Since the absorption portions  21  absorb the deformation stress of the connecting portion  1 , the elastic structure of the contact portion  3  is protected, the reduction of the contact area and the clamping force between the contact elastic pieces  31  and the mating member  200  caused by the deformation of the contact elastic pieces  31  can be avoided, and the unfavorable electric contact caused by the reduction of the contact area and the reduction of the clamping force can be further avoided. 
       FIG. 7  shows a second embodiment of the present invention. As shown in  FIG. 7 , a barrel terminal  100  is a barrel body formed by curling a metal sheet with good electric conductivity. Referring to step a of  FIG. 7 , an expanded view of a metal sheet before the barrel terminal  100  is molded is shown. Multiple fence-shaped absorption portions  21  and multiple contact elastic pieces  31 , which are uniformly distributed, are directly punched on the metal sheet. A large end bar  41  and a small end bar  42  are formed at two ends of the metal sheet, and a spacing bar  43  is provided between the absorption portions  21  and the contact elastic pieces  31 . The spacing bar  43  is connected with the large end bar  41  through the absorption portions  21 , and the small end bar  42  is connected with the spacing bar  43  through the contact elastic pieces  21 . Referring to step b of  FIG. 7 , the metal sheet is curled to form the barrel body with a gap. The barrel body has a central axis X. The large end bar  41  is curled to form the tube wall  11  which is encircled to form the connection cavity  10 , the absorption portions  21  are curled to form the buffer cavity  20 , and the contact elastic pieces  31  are curled to form the contact cavity  30 . The connection cavity  10 , the buffer cavity  20  and the contact cavity  30  are communicated with one another. The spacing bar  43  is curled to form the front end ring  32 , and the small end bar  42  is curled to form the rear end ring  33 . Referring to step c of  FIG. 7 , the barrel body is soldered in a solder seam. Referring to step d of  FIG. 7 , an open end of the tube wall  11  is radially expanded outward, so that the connection cavity  10  forms a first cavity  101  and a second cavity  102  which are connected with each other, and the open end of the rear end ring  33  is radially expanded outward to form a flared opening  34 . Referring to step e of  FIG. 7 , the contact elastic pieces  31  are twisted along the central axis X, so that the contact elastic pieces  31  incline along the central axis X, the middle position of each contact elastic piece  31  is arched towards the contact cavity  30  relative to the two ends, and the contact elastic pieces  31  are arranged in an arc shape. The middle position of each contact elastic piece  31  is a contact point  310 , and the mating member  200  is inserted into the contact cavity  30  in parallel from one side of the barrel terminal  100  and electrically contacts the contact point  310 . 
       FIGS. 8 and 9  show a third embodiment of the present invention. As shown in  FIGS. 8 and 9 , the connecting portion  1  has a connection cavity  10  and a tube wall  11  incompletely covering the connection cavity  10 . The cable  300  has a core portion  302 . The core portion  302  is inserted into the connection cavity  10  and fixedly soldered to the tube wall  11 . The cable  300  is electrically connected with the barrel terminal  100 . The buffer portion  2  absorbs the deformation stress generated by the soldering of the connecting portion, and the stress is prevented from being transferred to the contact portion  3 . 
     In summary, the barrel terminal according to certain embodiments of the present invention has the following beneficial advantages: 
     1. The barrel terminal  100  has a buffer portion  2 , the buffer portion has multiple absorption portions  21 , and the multiple absorption portions  21  are encircled along the central axis X to form a buffer cavity  20 . When the absorption portions  21  absorb the deformation stress of the connecting portion  1 , the absorption portions  21  are deformed toward the buffer cavity  20 , and the buffer cavity  20  supplies a buffer deformation space to the absorption portions  21 . The buffer portion  2  absorbs the deformation stress of the connecting portion  1 , so that the stress cannot be transferred to the contact portion  3 , the elastic structure of the contact portion  3  is protected, the reduction of the contact area and the clamping force between the contact elastic pieces  31  and the mating member  200  caused by the deformation of the contact elastic pieces  31  is avoided, and the unstable electric connection between the barrel terminal  100  and the mating member  200  caused by the reduction of the contact area and the reduction of the clamping force can be further avoided. 
     2. The distance from each absorption portion  21  to the central axis X is equal, so that the buffer portion  2  can uniformly absorb the deformation stress of the connecting portion  1 , and the stress absorbed by the buffer portion  2  is prevented from being concentrated at one point. 
     3. The contact portion  3  has multiple contact elastic pieces  31 , and the middle position of each contact elastic piece  31  is arched toward the contact cavity  30  relative to the two ends. The middle position of each contact elastic piece  31  is a contact point  310 , and the mating member  200  is inserted into the barrel terminal  100  and electrically contacts the contact point  310 . The multiple contact points  310  increase the contact area between the barrel terminal  100  and the mating member  200 , and the contact points  310  are arched towards the contact cavity  30  and elastically contact the mating member  200 , so that the clamping force of the barrel terminal  100  to the mating member  200  is increased, and the electric connection between the barrel terminal  100  and the mating member  200  is good. 
     The foregoing description of the exemplary embodiments of the invention has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching. 
     The embodiments are chosen and described in order to explain the principles of the invention and their practical application so as to activate others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.