Abstract:
A synchronizer is provided for torsionally connecting a gear to an axially aligned shaft. The synchronizer includes a hub connected with the shaft, a sleeve having an inner diameter with spline teeth for torsional connection with the hub being axially movable upon the hub, a blocking ring torsionally connected on the hub having an angular lost motion relationship with the sleeve, the blocking ring having at least a first annular conical friction surface orientated radially inward and axially toward the hub and a second annular conical friction surface oriented radially inward and axially outward from the hub, the blocking ring having blocking cogs preventing axial movement of the sleeve toward the gear when the gear is in a non-synchronous condition, and an engagement ring for fixed connection with the gear, the engagement ring having a complementary annular conical friction surfaces.

Description:
FIELD OF THE INVENTION 
       [0001]    The field of the present invention is that of synchronizers useful in automotive transmissions and methods of utilization thereof. 
       BACKGROUND OF THE INVENTION 
       [0002]    In many automotive manual transmissions or dual clutch transmissions power is transferred between meshed gears mounted on two parallel rotating shafts. An example of a dual clutch transmission is provided in commonly assigned U.S. Pat. No. 8,342,051. On one or more of the parallel shafts, there are multiple rotatably mounted gears. The gear ratio of the transmission is dependent upon which gears are selectively torsionally connected to the shafts. As is apparent to those familiar with the art, for the gear to be torsionally connected to a shaft, the gear must first have its speed synchronized with the speed of the shaft. Accordingly synchronizers are provided to torsionally connect the gears to their respective shaft. 
         [0003]    Referring to  FIGS. 1-9 , a dual gear synchronizer  10  that works similarly to that shown and explained in Frost, U.S. Pat. No. 5,135,087 (disclosure incorporated by reference herein). Since operation of the dual gear synchronizer is essentially identical for both sides of the synchronizer  10  only one side is explained. The synchronizer  10  has a hub  12 . The hub  12  is spline connected to a shaft  17  (shown in  FIG. 9 ) along the hub&#39;s inner diameter inner diameter  14  ( FIG. 2 ). The hub  12  along its outer diameter has six circumferential segments  16  with spline teeth  18 . Positioned between the segments  16  are three geometrically spaced sleeve detent members  20 . The detent members  20  capture a coil spring  19  ( FIG. 9 ) radially outward loaded bearing ball  22 . The detent members can also travel axially with respect to the hub  12  between the segments  16 . 
         [0004]    Surrounding the hub  12  and torsionally connected thereto is a sleeve  24 . The sleeve  24  has two axially spaced apart rims  25  projecting radially outward to provide a nest  26  to capture a shift fork  28  (shown partially in phantom in  FIG. 9 ) of the transmission. An inner diameter  27  ( FIG. 1 ) of the sleeve  24  has a series of axial spline teeth  30  allowing the sleeve  26  to be torsionally fixedly connected and axially movable on the spline teeth  18  of the hub. The sleeve detents  20  press balls  22  into depressions  34  ( FIG. 1 ) provided in the inner diameter the sleeve  24 . 
         [0005]    Lateral of the sleeve  24  is a blocking ring(s)  36 . The blocking ring  36  has the geometrically spaced tabs  38  that torsionally connect the blocking ring with the hub  12  in a lost motion manner. Tab  38  is clocked or captured between hub segment surfaces  47  and  49  of the hub. The angular shift (lost motion) between the hub or sleeve  24  when tab  38  surface  41  contacts hub segment surface  47  to where tab surface  43  contacts hub surface  49  is approximately 6 degrees. The blocking ring  36  also has an operatively associated alpha friction surface  40 . The blocking ring  36  also has a series of blocking cogs or teeth  42 . 
         [0006]    Lateral of each blocking ring  36  is an intermediate ring  48 . Lateral of the intermediate ring  48  is an inner ring  52 . Lateral of the inner ring  52  is an engagement ring  60 . The engagement ring  60  is fixedly connected with a gear  61  (shown partially in  FIG. 9 ) to be torsionally connected with the shaft  17 . The engagement ring  60  has cogs  63  (shown in greater detail in  FIGS. 3-8 ). Intermediate ring  48  has tabs  62  axially extending toward the engagement ring  60 . The tabs  48  extend into radial slots  64  of the engagement ring to torsionally connect intermediate ring  48  with the engagement ring  60 . In a similar fashion the inner ring  52  has axially extending tabs  68 . The tabs  68  extend into radial slots  78  provided in the blocking ring to torsionally connect inner ring  52  to the blocking ring  36  and to operatively associate inner ring alpha friction surface  51  with the blocking ring  36 . 
         [0007]    In operation the shift fork  28  (not shown in  FIGS. 3-8 ) moves sleeve  24  leftward from a neutral position shown in  FIG. 3  to a pre-synchronization position shown in  FIG. 4 . The sleeves  24  leftward movement ( FIG. 4 ) also causes the sleeve detents  20  to be moved leftward in relationship to the hub  12  causing detent side surface  71  to push against blocking ring side surface  73  (see additionally  FIG. 9 ). The leftward movement of the blocking ring  36  causes the beta friction surface  40  of the blocking ring  36  to contact in sliding frictional engagement the outer friction surface  75  of the intermediate ring  48 . Since the intermediate ring  48  via the tab  62  is torsionally connected with the engagement ring  60  the friction surface  75  and its operatively associated engagement ring  60  are accelerated. Additionally intermediate ring  48  is frictionally driven by inner ring  52 , the inner ring  52  being torsionally connected with the blocking ring  36 . Therefore the intermediate ring  36  on its outer  75  and inner  80  surfaces through sliding frictional engagement is acted upon by blocker ring  36  to accelerate the engagement ring  60 . Assuming rotation of the shaft  17  and the yoke in a direction  81  ( FIG. 1 ), intermediate ring tab surface  43  is contacting surface  49  of the hub. With the drag caused by the inertia of the accelerating gear  61 /engagement ring  60  on the blocking ring  36 , the blocking ring tab surface  43  contacts hub surface  49  with increased force. As shown in  FIG. 5  the clogs  42  of the blocking ring are now in a blocking position contacting angled front tips  85  of the spline teeth  30  of the sleeve, preventing further axial movement of the sleeve  24  ( FIG. 5 ). Until the engagement ring  60  and its connected gear  61  are synchronized with the sleeve  24 , the clogs  42  of the blocking ring continue to prevent further leftward travel of the sleeve  24 . Eventually the engagement ring  60  (and connected gear  61 ) is brought to a speed that is synchronized with that of the shaft  17  (equal to that of the hub  12 ). Upon reaching synchronous speed leftward movement of the sleeve  22  ( FIG. 6 ) now causes the tips  85  of the sleeve teeth to cam the clogs  42  of the locking ring over to allow continued leftward movement of the sleeve  24  to the point wherein the sleeve spline teeth  30  extend ( FIG. 7 ) to the spacing between the engagement ring cogs  63 . Continued movement of the sleeve  24  locks in the engagement ring  60  and the torsional connection of gear with the shaft is complete ( FIG. 8 ). 
         [0008]    It is readily known to those skilled in the art for the last decades there has been a major push to increase the fuel economy of automotive vehicles. Accordingly, it is desirable to reduce the spatial envelope of the power train as much as possible to maximize interior passenger room of the vehicle while minimizing the spatial envelope of the vehicle body to reduce aerodynamic drag thereby increasing fuel efficiency. Therefore, it is desirable to provide a synchronizer in a smaller spatial envelope than those revealed previously. It is also desirable to provide a synchronizer with high synchronization capacity while at the same time minimizing the number of components. 
       SUMMARY OF THE INVENTION 
       [0009]    To make manifest the above delineated and other desires, a revelation of the present invention is brought forth. In a preferred embodiment, the present invention brings forth a freedom of a synchronizer for torsionally connecting a gear to an axially aligned shaft in a smaller axial spatial envelope. The preferred embodiment includes a hub for torsional connection with the shaft. A sleeve is provided having an inner diameter with spline teeth for torsional connection with the hub and is axially movable upon the hub. A sleeve detent is provided axially slidable on the hub and is positioned between the hub and the sleeve. A blocking ring is provided, torsionally connected on the hub having an angular lost motion relationship with the sleeve. The blocking ring has first and second annular conical friction surfaces. The blocking ring also has blocking cogs preventing axial movement of the sleeve towards the gear when the gear is in a nonsynchronous condition. 
         [0010]    An engagement ring is also provided having fixed connection with the gear. The engagement ring has annular conical friction surfaces complementary with the annular conical friction surfaces of the blocking ring. 
         [0011]    In another preferred embodiment of the present invention, the synchronizer sleeve has long and short teeth. The sleeve&#39;s short teeth interact with the cogs of the blocking ring. The sleeve&#39;s long teeth transmit torque from the hub to the gear via the engagement ring cogs. The novel arrangement of short and long teeth of the sleeve allows the axial spatial envelope of the synchronizer to be reduced. 
         [0012]    In yet another preferred embodiment the present invention synchronizer has a compliant detent between the hub and the blocking ring to bias the blocking ring towards the hub allowing the blocking ring to be axially positioned away from the engagement ring during non-actuation of the gear thereby reducing rattle and resulting noise of the synchronizer. 
         [0013]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0015]      FIG. 1  is an exploded view of a synchronizer prior to the present invention; 
           [0016]      FIG. 2  is an assembled partially sectioned perspective view of the synchronizer shown in  FIG. 1 ; 
           [0017]      FIG. 3  is an operational view of the synchronizer shown in  FIG. 1 ; 
           [0018]      FIG. 4  is an operational view of the synchronizer shown in  FIG. 1  subsequent to the position shown in  FIG. 3 ; 
           [0019]      FIG. 5  is an operational view of the synchronizer shown in  FIG. 1  subsequent to the position shown in  FIG. 4 ; 
           [0020]      FIG. 6  is an operational view of the synchronizer shown in  FIG. 1  subsequent to the position shown in  FIG. 5 ; 
           [0021]      FIG. 7  is an operational view of the synchronizer shown in  FIG. 1  subsequent to the position shown in  FIG. 6 ; 
           [0022]      FIG. 8  is an operational view of the synchronizer shown in  FIG. 1  subsequent to the position shown in  FIG. 7 ; 
           [0023]      FIG. 9  is an enlarged partial sectional view of the synchronizer shown in  FIGS. 1 and 2 ; 
           [0024]      FIG. 10  is a sectional view of a preferred embodiment synchronizer according to the present invention; 
           [0025]      FIG. 11  is an enlarged partial sectional view of an alternate preferred embodiment synchronizer having to the preferred embodiment synchronizer shown in  FIG. 14 ; 
           [0026]      FIG. 12  is an enlarged partial sectional view of another alternate preferred embodiment synchronizer to the preferred embodiment synchronizer that is shown in  FIG. 14 ; 
           [0027]      FIG. 13  is a schematic roll out view taken along arcuate line  13 - 13  of  FIG. 10 ; 
           [0028]      FIG. 14  is a sectional view of a single cone preferred embodiment synchronizer according to the present invention taken along line  14 - 14  of  FIG. 10 ; 
           [0029]      FIG. 15  is a view similar to  FIG. 13  illustrating operation of the preferred embodiment synchronizer according to the present invention; 
           [0030]      FIG. 16  is an operational view of the preferred embodiment synchronizer according to the present invention, subsequent to the position shown in  FIG. 14 ; 
           [0031]      FIG. 17  is an operational view subsequent to the position shown in  FIG. 15 ; 
           [0032]      FIG. 18  is an operational view subsequent to the position shown in  FIG. 16 ; 
           [0033]      FIG. 19  is an operational view subsequent to the position shown in  FIG. 17 ; 
           [0034]      FIG. 20  is an operational view subsequent to the position shown in  FIG. 18 ; 
           [0035]      FIG. 21  is an exploded view of the preferred embodiment synchronizer shown in  FIGS. 10 and 13 through 20 ; 
           [0036]      FIG. 22  is an exploded view of yet another alternate preferred embodiment synchronizer the present invention illustrating a sleeve hub, blocking ring and engagement ring that is positioned on the opposite side of the hub from the illustrated blocking ring; 
           [0037]      FIG. 23  is a side assembled elevational view of the synchronizer shown in  FIG. 22 ; 
           [0038]      FIG. 24  is a sectional view taken along line  24 - 24  of  FIG. 23 ; 
           [0039]      FIG. 25  is a sectional view taken along line  25 - 25  of  FIG. 23 ; and 
           [0040]      FIG. 26  is a sectional view taken along line  26 - 26  of  FIG. 25 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0041]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0042]    Referring primarily to  FIGS. 14 and 21  and additionally to  FIGS. 10, 13 and 15-20 , a duel gear synchronizer  107  of the present invention has a hub  112 . Hub  112  has gaps or indentions  115  for receipt of detents  120 . Hub  112  has  3  geometrically spaced segments  116  having spline teeth  118  in a manner similar to that described for prior hub  12 . 
         [0043]    Sleeve  124  has two spaced apart rims  125  projecting radially outward to provide a nest  126  to capture a shift fork  28  as previously described. An inner diameter  127  of the sleeve has three sets of four geometrically spaced axially short spline teeth  131  ( FIG. 13 ) with the remainder of the spline teeth being axially long spline teeth  130 . The short teeth  131  are aligned with indentions  115  between the hub segments  116 . 
         [0044]    Lateral of the sleeve  124  is a blocking ring(s)  136 . The blocking ring  136  has three geometrically spaced mounts  138  with edges  141  and  143  that torsionally connect the blocking ring  136  with the hub  112  and sleeve  124  in a lost motion manner with hub indention edges  147  and  149  as previously described for synchronizer  10 . The blocking ring  136  has three sets of geometrically spaced blocking cogs  142  with the remainder  133  of an outer circumference of the blocking ring being smooth so as to fit radially within the long spline teeth  130  of the sleeve inner diameter. 
         [0045]    The blocking ring  136  has at least one (alpha) first annular conical friction surface  200  orientated radially inward and axially towards the hub  112 . The blocking ring  136  also has at least one (alpha) second conical friction surface  202  are orientated radially inward axially away from the hub  112 . 
         [0046]    Synchronizer  107  also has for connection with a gear  161  an engagement ring  160 . The engagement ring  160  has at least one corresponding (beta) first annular conical friction surface  201  corresponding with the first annular conical friction surface  200  of the blocking ring. The engagement ring  160  also has at least one (beta) second conical friction surface  203  corresponding with the second conical friction surface  202  of the blocking ring. 
         [0047]    Typically, the first friction surface  200  is angled between 6.5 and 9 degrees from horizontal. Typically the second friction surface is angled between 6.5 and 9 degrees from horizontal. In many applications the first friction surface  201  and  203  have angles corresponding to that for friction surfaces  200  and  202  however, if desired the angles made slightly differ to achieve a wedging effect. In the embodiments shown in  FIGS. 11, 12 and 14  the annular conical friction surfaces are generated from a straight line however other curvilinear shapes involving semi straight segments generated from quadratic functions or similar shapes can be utilized. The annular friction conical surfaces can be coated with a molybdenum material, paper, or diamond like carbon material. A diamond like carbon material is sold under the trademark of CeraTough-D™ DLC coating manufactured by IBC Coating Technologies. The embodiment  107  of  FIG. 14  illustrates a single cone synchronizer the present invention. The embodiment of  FIG. 11  illustrates a dual cone synchronizer  307  the present invention that is substantially similar to synchronizer  107 . The embodiments  407  and  417  of  FIGS. 12 and 22-26  respectively illustrate special embodiments of dual cone synchronizers of the present invention which have modifications to allow them to be highly useful in extreme narrow axial space applications. 
         [0048]    In synchronizers  107  and  307  the first and second friction surfaces  200 ,  202  of the blocking rings  136 ,  236  axially extend beyond the blocking cogs  142  of the blocking ring. Synchronizer  307  has friction surfaces  200  and  202  that extend axially to a length equal to a position of the engagement ring cogs  163 . Additionally, in synchronizer  107  friction surface  200  differs in length from the longer friction surface  202 . In synchronizer  407  ( FIG. 12 ) the friction surfaces  200 ,  202  of the blocking ring  336  do not axially extend beyond the blocking cogs  342  of the blocking ring  336 , thereby aiding the use of synchronizer  407  in an extreme narrow application. 
         [0049]    In synchronizers  107  and  307  the sleeve  124  as mentioned previously has long teeth  130  and short teeth  131 . Short teeth  131  are interlocked with teeth  129  of the sleeve detent. Long teeth  130  of the sleeve are engaged with long teeth  108  of the hub. Since the blocking ring  136  has smooth portions  133  the blocking ring, the cogs  142  of the blocking ring are axially overlapped with the short teeth  131  and the long teeth  130  of the sleeve  124 . 
         [0050]    In operation, a shift fork  28  moves the sleeve  124  leftward from a position shown in  FIGS. 13 and 14  to a position shown in  FIGS. 15 and 16  as previously described for sleeve  24 . Sleeve detent  120  is pulled so that its surface  171  contacts surface  173  of the blocker ring  136  to initiate engagement of the blocker ring  136  frictionally with the engagement ring  160 . Mount edge  141  is forced into hub indention edge  149 . This causes the tips of blocker ring cogs  142  to block further leftward movement of the sleeve by their engagement with the short teeth  131  of the sleeve ( FIG. 15 ). After synchronization of gear  161  is achieved, the short teeth  131  of the sleeve displace cogs  142  to allow further movement of the sleeve  124  ( FIGS. 17 and 18 ). Since the long teeth  130  of the sleeve already axially extend beyond cogs  142  of the blocker ring the travel distance required long teeth of the sleeve  131  to interlock with the cogs  163  of the engagement ring is reduced as compared with the travel required of the synchronizer  10  as previously described. Long teeth  130  side surface  151  of the sleeve are angled to make with a corresponding draft angle surface  157  on the cogs  163  to continue engagement when the gear  161  is under load ( FIGS. 19 and 20 ). The configuration of synchronizers  107  and  307  reduces the axial space required by the synchronizer and also the radial space required by the synchronizers  107 ,  307  due to the configuration of the annular conical friction surfaces. Additionally, synchronizer  307  typically has a much greater torsional capacity than the synchronizer  10 , while not only reducing the axial and radial space envelope of the synchronizer but additionally the need for an intermediate and an inner ring. 
         [0051]    The synchronizer  407  has a sleeve  127  more akin to sleeve  24  as previously described with only one size of teeth  129  along its interior diameter. 
         [0052]    Referring to  FIGS. 22-26 , a narrow configuration dual gear synchronizer  417  according to the present invention has a hub  412 . Hub  412  has 6 teeth segments  415  with spline teeth  418 . Geometrically spaced between the two teeth segments  415  are three geometrically spaced indentions  525 . Axially slidably mounted, within indentions  525  are three sleeve detents  520 . 
         [0053]    Synchronizer  417  also has a blocking ring  436  (only one blocking gear shown in  FIG. 22 ) having cogs  442 . Blocking ring  436  also has three geometrically spaced windows  530 . Additionally blocking ring  436  has three sets of geometrically spaced oil slots  504  and  505  to facilitate lubrication. 
         [0054]    Blocking ring  436  has a mount  438  with side edges  441  and  443  to clock or give a lost motion relationship with the sleeve  424  and hub  412  by alternately contacting hub edges  547  and  549  in a manner similar to that described for synchronizer  107 . 
         [0055]    Synchronizer  417  has a sleeve  424 . Sleeve  424  has rims  425  and a nest  426  that function in a manner similar to that previously described for synchronizer  107 . An interior of the sleeve  424  has spline gear teeth  430 . The sleeve  424  along its inner diameter has three geometrically spaced limit blocks  500  having contact surfaces on both sides of  502 . Limit block  500  limits the axial displacement of the sleeve  424  with respect to the hub  412  by contact with the teeth  463  of the engagement ring  460  (note: the engagement ring  460  that is on the right side of blocking ring  436  in  FIG. 22  is omitted from the illustration). The blocking ring has three geometrically spaced slots  530  that allow passage of the limit block upon axial movement of sleeve. 
         [0056]    Synchronizer  407  additionally has within its hub  412  spring-loaded blocking ring detent balls  512  biased radially outward by springs  514 . The detent balls  512  contact the bottom end of the blocking ring in a partial semi spherical depression  526  at an inner diameter of the blocking ring (see  FIG. 26 ). The blocking ring detent balls  512  bias the blocking rings  436  to a position axially away from the engagement ring  460  when a gear (not shown) attached to the engagement ring  460  is not being utilized. The axial biasing force of the detent balls  512  is overcome when the shift fork (not shown) via the sleeve  424  pulls the sleeve detent  520  to engage the blocking ring  436  into the engagement ring  460 . However, the biasing force of the spring loaded ball  512  pulls back the blocking ring  436  away from engagement ring  460  whenever a gear connected with the engagement ring is released by the sleeve  424  by the movement of the sleeve  424  back to a non-engaged position by the shift fork. 
         [0057]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.