Abstract:
A dual clutch transmission may include: a control bar including a hole; a first rail and a second rail that are respectively disposed along the control bar; first springs biasing the first rail and the second rail respectively; a first stopper and a second stopper that are mounted in respective inner grooves of the first rail and the second rail; second springs that elastically support the stoppers and insert the stoppers into the hole according to the movement of the rails; and a first release rug and a second release rug selectively holding the stoppers.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority to Korean Patent Application No. 10-2007-0124356 filed Dec. 3, 2007, the entire contents of which application is incorporated herein for all purposes by this reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a dual clutch transmission, and more particularly to a dual clutch transmission that prevents gears from double engagement and that smoothly operates gear shifting. 
         [0004]    2. Description of Related Art 
         [0005]    A dual clutch transmission includes two clutches in a transmission case so as to shift gear. 
         [0006]    Generally, the dual clutch transmission uses two clutches to selectively transmit torque that is input from an engine to two input shafts, and the gears that are mounted on the two input shafts are engaged selectively from each other such that a gear shift can be operated. 
         [0007]    The dual clutch transmission embodies a high speed compact transmission higher than a fifth speed 
         [0008]    Also, a synchronizing device and an automated shift gear (ASG) are used to help a manual shift in the dual clutch transmission. 
         [0009]    Generally, the clutch is disconnected so that a shift is securely operated, after the shift the clutch is connected to transfer engine torque to a wheel. However, while the first clutch is connected to the engine, a gear that is disposed in the second clutch is simultaneously connected to the engine in the double clutch system. 
         [0010]    This is called pre-selection. The odd speeds are connected to the first clutch and the even speeds are connected to the second clutch. 
         [0011]    For example, while a vehicle is running in a fourth speed by using the second clutch in accordance with a running state of the vehicle, a third speed gear or a fifth speed gear is previously rotated according to the rotation of the first clutch. 
         [0012]    Accordingly, in order to shift from the third speed to the fifth speed, it is necessary that the third speed gear is disengaged and the fifth speed gear is engaged. While likewise, in order to shift from the fifth speed to the third speed, it is necessary that the fifth speed gear is disengaged and the third speed gear is engaged. 
         [0013]    That is, a mechanism is necessary to disengage the third speed gear and engage the fifth speed gear, and vice versa, wherein the mechanism is to be swiftly and repeatedly operated. 
         [0014]    Accordingly, a device for preventing double engagement, that is, for preventing the third speed and the fifth speed from being simultaneously engaged, has been developed, however, there is a problem in which the structure of the device is complicated and several actuators are required to be used. 
         [0015]    The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
       BRIEF SUMMARY OF THE INVENTION 
       [0016]    Various aspects of the present invention are directed to provide a dual clutch transmission having advantages of preventing gears from double engagement, such as when shifting from fifth speed to third speed. 
         [0017]    In an aspect of the present invention, a dual clutch transmission that is equipped with a double clutch, includes a first clutch and a second clutch, and a device for preventing double engagement, wherein the device for preventing double engagement may include control bar in which a hole is formed from a first surface to a second surface that is opposite to each other, a first rail and a second rail that are respectively disposed along the first surface and the second surface of the control bar, first springs that respectively bias the first rail and the second rail to maintain a neutral position in a normal state, a first stopper and a second stopper that are mounted in respective inner grooves of the first rail and the second rail and in which the end portions thereof are disposed to protrude from the first surface and the second surface thereof second springs that elastically support the first and second stoppers and insert the first or second stopper into the hole according to the movement of the first or second rails, and/or a first release rug and a second release rug that respectively extends from the first rail and the second rail along the third surface and the fourth surface of the control bar, wherein a dent, in which the first or second stopper is mounted, is formed in the middle of an end surface of the first and second release rugs, and a knoll is formed adjacent to the dent so as to push the first or second stopper according to the movement of the first or second rail. 
         [0018]    A groove may be formed on the first and second surface of the control bar and the first and second stoppers are mounted in the groove and thereby the first or second rail is positioned in the neutral position in the normal state. 
         [0019]    The groove may be formed adjacent to the hole. 
         [0020]    The groove may be symmetrically formed around the hole. 
         [0021]    The first stopper may be disposed at both sides based on the first release rug and the second stopper may be disposed at both sides based on the second release rug. 
         [0022]    A first fork and a first shift rug for shifting may be connected to the first rail. 
         [0023]    A second fork and a second shift rug for shifting may be connected to the second rail. 
         [0024]    In another aspect of the present invention, a dual clutch transmission that is equipped with a double clutch, including a first clutch and a second clutch, and a device for preventing double engagement, wherein the device for preventing double engagement may include a control bar including an upper surface and lower surface, a hole, and grooves, wherein the hole is configured to pass through the upper surface and lower surface and the grooves are formed near the hole, a first rail and a second rail that are respectively disposed on and below the control bar, first spring biasing the first rail to maintain a neutral position in a normal state, second spring biasing the second rail to maintain a neutral position in a normal state, a first stopper and a second stopper that are mounted in respective inner grooves of the first rail and the second rail and in which the end portions thereof are disposed to selectively protrude from the upper surface and the lower surface, second springs that elastically support the first and second stoppers and insert the first or second stoppers into the hole according to the movement of the first or second rail, and/or a first release rug and a second release rug that respectively extend from the first rail and the second rail along the third surface and the fourth surface at both sides of the control bar, wherein a dent, in which the first or second stopper mounts, is formed in the middle of an end surface of the first and second release rugs, and a knoll is formed adjacent to the dent so as to push the first or second stopper according to the movement of the first or second rail. 
         [0025]    In further another aspect of the present invention, a dual clutch transmission that is equipped with a double clutch, including a first clutch and a second clutch, and a device for preventing double engagement, wherein the device for preventing double engagement may include first and second cases, first control bar disposed at the middle of the inside of the first case and extending in a longitudinal direction thereof, second control bar disposed at the middle of the inside of the second case and extending in a longitudinal direction thereof, wherein a hole is formed between one end portion of the first control bar and one end portion of the second control bar, a first rail slidably disposed on first surfaces of the first and second control bars, a second rail slidably disposed on second surfaces of the first and second control bars, first elastic member and second elastic member that respectively bias the first and second rails to maintain a neutral position in a normal state, a first stopper mounted in an inner groove of the first rail and one end of which protrudes toward the first control bar, the first stopper moving in the first case, wherein a third elastic member supports the first stopper and selectively inserts the first stopper into the hole according to the movement of the first rail, a second stopper mounted in an inner groove of the first rail and one end of which protrudes toward the second control bar, the second stopper moving in the second case, wherein a fourth elastic member supports the second stopper and selectively inserts the second stopper into the hole according to the movement of the first rail, a third stopper mounted in an inner groove of the second rail and one end of which protrudes toward the first control bar, the third stopper moving in the first case, wherein a fifth elastic member supports the third stopper and selectively inserts the third stopper into the hole according to the movement of the second rail, a fourth stopper mounted in an inner groove of the second rail and one end of which protrudes toward the second control bar, the fourth stopper moving in the second case, wherein a sixth elastic member supports the fourth stopper and selectively inserts the fourth stopper into the hole according to the movement of the second rail, a first release rug extending from the first rail between the first and second stoppers, the first release rug including a dent to selectively receive the third or fourth stopper and a knoll formed adjacent to the dent to selectively release the third or fourth stopper according to movement of the first rail, and/or a second release rug extending from the second rail between the third and fourth stoppers, wherein the second release rug includes a dent to selectively receive the first or second stopper and a knoll formed adjacent to the dent to selectively release the first or second stopper according to movement of the second rail. 
         [0026]    First and second grooves may be formed on the first surface of the respective first and second control bars at the one end thereof and third and fourth grooves are formed on the second surface of the respective first and second control bars at the one end thereof, the first and second stopper being mounted in the first and second grooves to maintain the first rail in the neutral position in the normal state and the third and fourth stopper being mounted in the third and fourth grooves to maintain the second rail in the neutral position in the normal state. 
         [0027]    The first, second, third, and fourth grooves may be formed adjacent to the hole. 
         [0028]    The first and second grooves may be symmetrically formed with respect to the hole and the third and fourth grooves may be symmetrically formed with respect to the hole. 
         [0029]    A first fork for shifting may be connected to the first rail. A second fork for shifting may be connected to the second rail. 
         [0030]    The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description of the Invention, which together serve to explain certain principles of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]      FIG. 1  is a schematic diagram of an exemplary dual clutch transmission according to an exemplary embodiment of the present invention. 
           [0032]      FIG. 2  is a cross-sectional view of a device for preventing double engagement that is mounted on a dual clutch transmission according to an exemplary embodiment of the present invention. 
           [0033]      FIG. 3  is a partial exploded sectional view of a device for preventing double engagement according to an exemplary embodiment of the present invention. 
           [0034]      FIG. 4  is a cross-sectional view of a device for preventing double engagement according to line II-II of  FIG. 2 . 
           [0035]      FIG. 5  is a cross-sectional view of a casing that is mounted on a device for preventing double engagement according to an exemplary embodiment of the present invention. 
           [0036]      FIG. 6A  to  FIG. 6D  are cross-sectional views showing operating statuses of a device for preventing double engagement according to an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]    Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
         [0038]      FIG. 1  is a schematic diagram of a dual clutch transmission according to various exemplary embodiments of the present invention. 
         [0039]    Referring to  FIG. 1 , a driving device includes an engine  2 , a base input shaft  4 , first and second clutches C 1  and C 2 , a first input shaft  6 , a second input shaft  8 , a first speed input gear  16 , a second speed input gear  12 , a third speed input gear  18 , a fourth speed input gear  14 , and a fifth speed input gear  10 . 
         [0040]    Also, the driving device further includes a first speed output gear  24 , a second speed output gear  22 , a third speed output gear  26 , a fourth speed output gear  32 , a fifth speed output gear  27 , a sixth speed output gear  30 , a reverse input gear  38 , a reverse output gear  36 , a first output shaft  20 , a second output shaft  28 , a first synchronizer SC 1 , a second synchronizer SC 2 , a third synchronizer SC 3 , and a fourth synchronizer SC 4 . 
         [0041]    The driving device includes a control portion I  00  and a device for preventing double engagement  105  that are respectively connected to the synchronizers (SC 1 , SC 2 , SC 3 , and SC 4 ). The control portion  100  substantially controls the synchronizers (SC 1 , SC 2 , SC 3 , and SC 4 ) and a device for preventing double engagement  105  so as to shift gear up and down. 
         [0042]    For example, the device for preventing double engagement  105  prevents the fifth speed output gear  27  and the third speed output gear  26  from being simultaneously connected to the first and second output shafts  20  and  28 . 
         [0043]    That is, when shifting speed from a third speed to a fifth speed, the third speed output gear  26  is disengaged from the first synchronizer SC 1  and the fourth synchronizer SC 4  is engaged with the fifth speed output gear. 
         [0044]    The respective synchronizers (SC 1 , SC 2 , SC 3 , and SC 4 ) are connected to a shift fork ( 315 ,  FIG. 2 ) and an actuator of a transmission. 
         [0045]      FIG. 2  is a cross-sectional view of a device for preventing double engagement  105  that is mounted on a dual clutch transmission according to various exemplary embodiments of the present invention. 
         [0046]    Referring to  FIG. 2 , the device for preventing double engagement  105  includes a case  200  comprising a first case  200   a  and a second case  200   b,  a control bar  202  including a first control bar  202   a  and a second control bar  202   b,  a first rail  210   a , a second rail  210   b,  a first spring  215   a , a second spring  215   b,  a first shift fork  315 , a second shift fork  615 , a first shift rug  300  and a second shift rug  600 . 
         [0047]    The first and second cases  200   a  and  200   b  are disposed at either side. The first control bar  202   a  is disposed at the middle of the inside of the first case  200   a  and the second control bar  202   b  is disposed at the middle of the inside of the second case  200   b.    
         [0048]    The first rail  210   a  and the second rail  210   b  are respectively disposed at both upper and lower portions of the control bars  202   a  and  202   b.  The first rail  210   a  is elastically supported by the first spring  215   a  at both sides thereof and the second rail  210   b  is elastically supported by the second spring  215   b  at both sides thereof. 
         [0049]    The first control bar  202   a  and the second control bar  202   b  are disposed in one straight line and the first and second rails  210   a  and  210   b  slide on both sides of these  202   a  and  202   b.    
         [0050]    When the first rail  210   a  and the second rail  210   b  are in the middle position the gear is in neutral. When the second rail  210   b  moves to the left the gear is in first speed, and when the second rail  210   b  moves to the right the gear is in third speed. When the first rail  210   a  moves to the left the gear is in reverse, and when the first rail  210   a  moves to the right the gear is in fifth speed. 
         [0051]    A first shift fork  315  and first shift rug  300  are disposed in the first rail  210   a  and these are moved by an actuator in left/right or up/down directions. A second shift fork  615  and a second shift rug  600  are also disposed in the second rail  210   b.    
         [0052]    Particularly, in various embodiments of the present invention, when the second rail  210   b  is in the third speed and the first rail  210   a  is in the neutral position and, if the first rail  210   a  moves to the fifth speed position, the second rail  210   b  automatically moves to the neutral position by the second spring  215   b.  Accordingly, it is prevented that the third speed and the fifth speed are simultaneously operated. 
         [0053]    A structure of the device for preventing double engagement  105  is explained in detail referring to  FIG. 3  and  FIG. 4 . 
         [0054]      FIG. 3  is a partial exploded sectional view of a device for preventing double engagement  105  according to various embodiments of the present invention.  FIGS. 3(   b ) and ( c ) are the other cross-sectional side views of ( a ). 
         [0055]    Referring to  FIGS. 3(   a ), ( b ), and ( c ), the first shift rug  300  and the first shift fork  315  are formed in the first rail  210   a.    
         [0056]    A first stopper  305   a , a second stopper  305   b,  a third spring  310   a,  and a fourth spring  310   b  are mounted on the first rail  210   a.  Also, a first release rug  320  is formed in the middle of the first rail  210   a.    
         [0057]    The first stopper  305   a  is elastically supported upwards by the third spring  310   a  and the second stopper  305   b  is elastically supported upwards by the fourth spring  310   b.    
         [0058]    End portions of the first and second stoppers  305   a  and  305   b  protrude from one upper surface of the first rail  210   a  by the third and fourth springs  310   a  and  310   b.    
         [0059]    A dent  320   a  is formed in the middle of the first release rug  320  and knolls  320   b  are formed at both sides based on the dent  320   a.  The first shift rug  300  and the first shift fork  315  are connected to an actuator that substantially shifts speed. 
         [0060]      FIGS. 3(   b ) and ( c ) show cross-sectional side views according to line III-III of  FIG. 3(   a ) in another exemplary embodiment, wherein the section of the first rail  210   a  has a quadrangular shape in ( b ), and the section of the first rail  210   a  has a circular shape in ( c ). 
         [0061]    The first release rug  320  and the first and second stoppers  305   a  and  305   b  are formed in an upper direction and the first shift fork  315  is formed in a lower direction of the first rail  210   a.  Also, the first shift rug  300  is formed in a side direction of the first rail  210   a.    
         [0062]      FIG. 4  is a cross-sectional view of a device for preventing double engagement according to line II-II of  FIG. 2 , wherein the section of the first and second rails  210   a  and  210   b  have a circular shape as shown in  FIG. 3(C) . 
         [0063]    As shown in  FIG. 4 , the section of the second control bar  202   b  has a quadrangular shape, and the second control bar  202   b  has a first surface  400  and a second surface  405  that are placed opposite each other and a third surface  410  and a fourth surface  415  that are placed each other. 
         [0064]    The second rail  210   b  is disposed at the first surface  400  (upper portion) of the second control bar  202   b,  and the first rail  210   a  is disposed at the second surface  405  (lower portion) of the second control bar  202   b.  Also, the second release rug  322  extends from the second rail  210   b  downwards and is disposed at the third surface  410  of the second control bar  202   b.    
         [0065]    Further, the first release rug  320  extends from the first rail  210   a  upwards and is disposed on the fourth surface  415  of the second control bar  202   b.    
         [0066]    Further, the end surface of the fourth stopper  311   a  is disposed to face or contact the first surface  400  of the second control bar  202   b  and the end surface of the first release rug  320  in the first rail  210   a,  and the end surface of the second stopper  305   b  is disposed to face or contact the end surface of the second surface  405  and the second release rug  322  in the second rail  210   b.    
         [0067]      FIG. 5  is a cross-sectional view of a casing that is mounted on a device for preventing double engagement according to an exemplary embodiment of the present invention. 
         [0068]    As shown in  FIG. 5 , the first control bar  202   a  and the second control bar  202   b  are disposed inside the casing  200 . A hole  505  is formed between the first control bar  202   a  and the second control bar  202   b.    
         [0069]    Grooves  500  are formed adjacent to the hole  505  in ends of the first and second control bars  202   a  and  202   b.  The grooves  500  are disposed around the hole  505 . 
         [0070]    Referring to  FIGS. 2 ,  4  and  5 , the fourth stopper  311   a  is mounted in the groove  500  according to the movement of the second rail  210   b.  Also, the second stopper  305   b  can be mounted in the groove  500  according to the movement of the first rail  210   a.    
         [0071]      FIG. 6A  to  FIG. 6D  are cross-sectional views showing operating statuses of a device for preventing double engagement according to an exemplary embodiment of the present invention. 
         [0072]    As shown in  FIG. 6A , when the second rail  210   b  moves in a right direction by an actuator, a third stopper  605   a  is inserted into the hole  505  ( FIG. 5 ) by the fifth spring  610   a.    
         [0073]    At this time, the third stopper  605   a  is mounted on the dent  320   a  ( FIG. 3 ) of the first release rug  320  that is formed in the first rail  210   a.    
         [0074]    As stated above, the third stopper  605   a  is inserted into the hole  505  ( FIG. 5 ) such that the third speed of a transmission is sustained. 
         [0075]    Next, as shown in  FIG. 6B , when the first rail  210   a  moves in a right direction by an actuator, the knoll  320   b  of the first release rug  320  ( FIG. 3 ) lifts up the third stopper  605   a.    
         [0076]    Next, as shown in  FIG. 6C , the second rail  210   b  is returned to the middle position (neutral) by the second spring  215   b  and the third stopper  605   a  and the fourth  311   a  are inserted into the groove  500  by the fifth spring  610   a  and the sixth spring  610   b  respectively. 
         [0077]    Next, as shown in  FIG. 6D , the first stopper  305   a  of the first rail  210   a  is inserted into the hole  505  and thus the position of the first rail  210   a  is retained. Accordingly, the fifth speed is completed and retained. 
         [0078]    As stated above, the second rail  210   b  is not moved by an actuator in the third speed position of the second rail  210   b,  but the third speed position of the second rail  210   b  is released by simply moving the first rail  210   a  to the position of the fifth speed. Accordingly, the third speed and the fifth speed are not simultaneously operated. 
         [0079]    For convenience in explanation and accurate definition in the appended claims, the terms “upper” and “lower” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
         [0080]    The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.