Abstract:
A steering tilt column assembly for a vehicle. The steering tilt column assembly is capable of implementing a stable engaged state of an engaged fixing gear and driving gear for continuing a tilting state, removing some parts by directly operating an upward roation operation of a driving gear using a tilt lever, preventing a noise and loosening by preventing a bolt used for a lever hinge of a tilt lever from affecting to a rotation friction during a rotation of a tilt lever, increasing an impact absorbing effect and unit cost by improving a material and structure of an initial impact absorbing capsule used for a mounting bracket, and implementing an impact absorbing and fixed engagement without using a dual column by making an engaging structure of a lower portion of a column and a lower bracket have a cross sectional portion with a decreased diameter.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a steering tilt column assembly for a vehicle, and in particular to a steering tilt column assembly for a vehicle which is capable of implementing a stable engaged state of an engaged fixing gear and driving gear for continuing a tilting state, removing some parts by directly operating an upward rotation operation of a driving gear using a tilt lever, preventing a noise and loosening by preventing a bolt used for a lever hinge of a tilt lever from affecting to a rotation friction during a rotation of a tilt lever, increasing an impact absorbing effect and unit cost by improving a material and structure of an initial impact absorbing capsule used for a mounting bracket, and implementing an impact absorbing and fixed engagement without using a dual column by making an engaging structure of a lower portion of a column and a lower bracket have a cross sectional portion with a decreased diameter. 
   2. Description of the Background Art 
   Generally, a vehicle steering tilt column assembly is installed in an outer portion of a steering shaft  20  adapted to transfer a rotational force from a steering wheel to a gear box for thereby supporting a rotation of the same and connecting to a vehicle body. 
     FIG. 1  is a view illustrating a conventional steering tilt column assembly. 
   As shown in  FIG. 1 , a unit for connecting a steering tilt column assembly to a vehicle body includes a mounting bracket  70  fixed in an intermediate position of the column  10 , a capsule  80  inserted into a slot at both sides of the mounting bracket, and a lower bracket  90  which is fixed in a lower position of the column  10  formed of an outer tube  10   a  and an inner tube  10   b , namely, in a lower portion of the inner tube  10   b.    
   The steering shaft  20  includes an upper and lower ends connected with a steering wheel and a gear box, respectively, and is connected with a universal joint adapted to transfer a rotational force in a bent state therebetween. 
   In addition, the steering column adapted to support the steering shaft includes a tilting apparatus adapted to maintain a bent state of the steering shaft and to adjust an angle of a steering wheel based on a driver&#39;s physical state. 
     FIG. 2  is a view illustrating the above tilting apparatus. 
   Here, a column bracket  30  is installed in an upper portion of the steering column  10 . A tilt bracket  40  is installed in an outer portion at both sides of the column bracket  30  for surrounding the same. The column bracket  30  and the tilt bracket  40  are connected with both ends of the split steering shaft  20 , respectively. 
   In addition, both sides of the column bracket  30  and the tilt bracket  40  are engaged to the tilt hinge  32 , respectively, and when the steering shaft  20  installed in the interior of the same is bent, the same is bent by the universal joint (not shown) based on a cooperation of the same. 
   A circular shaped fixing gear  31  which as the same center as the tilt hinge  32  and a threaded portion in an outer surface of the same is installed in an outer one side of the column bracket  30 . A driving gear  41  is formed in the tilt bracket  40  and is engaged with the fixing gear  31 . 
   Namely, one end of the driving gear  41  is engaged to the gear hinge  42  in the tilt bracket  40 , and a threaded portion engaged with a threaded portion of the fixing gear  31  is formed in an inner surface of the front end of the same and is elastically supported by a spring (not shown) based on a continuous engagement. 
   In addition, the tilt bracket  40  has a certain structure capable of rotating the driving gear  41  for angling the column bracket  30 , the tilt bracket  40  and the steering shaft  20  by distancing the engaged driving gear  41  and the fixing gear  31 . 
   Namely, there is provided a driving pin  43  protruded in one side of the driving gear  41 . A rotation member  50  is installed in a lower side of the driving pin  43  for thereby lifting the driving gear  41  through the driving pin  43 . The rotation member  50  is rotatably installed by the tilt hinge  32  at its center. 
   At this time, the rotation member  50  is installed between the tilt bracket  40  and the column bracket  30  in such a manner that opposite bent both ends of the same are passed through by the tilt hinge  32 , and the intermediate portion of the same covers an outer surface of the driving gear  41 . A rotation portion  51  is formed in a lower side of the driving pin  43 . 
   The portion in which the rotation portion  51  of the rotation member  50  is formed is connected with the gear hinge  42  which is a rotation point of the driving gear  41  and is recovered after the operation of the rotation member  50 . A recovering spring  54  is installed so that the tilt bracket  40  and the column bracket  30  are bent and recovered to their original positions. 
   Another recovering spring  55  is installed in the opposite portion of the recovering spring  54  with respect to the tilt hinge  32  so that the tilt bracket  40  and the column bracket  30  are bent to the other side and then are recovered. 
   In addition, A connection portion  52  which is longitudinally extended in the direction of the tilt bracket  40  and is bent is formed in the portion opposite to the rotation portion  51  of the rotation member  50 . The above connection potion  52  is connected through an end portion of the tilt lever  60  in which an intermediate portion is rotatably fixed in the lever hinge  61  formed in the tilt bracket  40  and the connection spring  53 . 
   Therefore, when pulling the handle of the tilt lever  60 , an end portion of the tilt lever  60  pushes the connection portion  52 , and the rotation member  50  is rotated. Therefore, the rotation portion  52  lifts up the driving gear  41 , and the driving gear  41  and the fixing gear  31  are distanced for thereby implementing a tilting function. 
   The steering tilt column assembly has an impact absorbing structure. 
   As one of the functions, it is directed to implementing an initial impact absorbing function. There are provided a capsule  80  inserted into the mounting bracket  70 , and a collapsing structure capable of implementing an impact absorbing function in the lower mounting portion. 
   As shown in  FIG. 1 , in the latter case, the steering column  10  is engaged with two hollow tubes of an outer tube  10   a  and an inner tube  10   b  for thereby contracting when an impact is transferred. 
   However, the conventional vehicle steering column tilting apparatus has the following problems. 
   First, since there are not any structure and apparatus for supporting the engagement of the fixing gear and the driving gear, the driving gear and the fixing gear are easily distanced when an external impact is transferred. 
   Namely, in the case that an abnormal external force or vibration occurs, since there is not any member for continuously preventing by pressing the driving gear  41  in the direction of the fixing gear  31 , the driving gear  41  may be lifted up for thereby unlocking the locked state. 
   Second, the rotation member  50  is installed between the tilt bracket and the column bracket using a tilt hinge for thereby lifting the driving gear  41 . However, the rotation member is formed of a thin steel plate rotating. Therefore, the strength is weak, and the rotation member  50  may be bent when an external impact is transferred, so that a pop-up problem (steering wheel is popped up) may occur. Furthermore, the rotation member  50  may be omitted by improving the structure. 
   Third, as shown in  FIG. 1 , in the steering column tilting apparatus, a common bolt  61   a  is engaged in the lever hinge  61  for rotatably fixing the tilt lever  60  in the tilt bracket  40 . 
   The engagement of the bolt  61   a  will be described. As shown in  FIG. 4 , there are needed a plate  60   b , a rivet  60   a , a bolt  61   a  and a lever  60 . In addition, a work process such as a bolt riveting portion of a tilt bracket is needed. Therefore, the fabrication cost is increased. 
   In addition, since the upper surfaces of the bolt  61   a  and the tilt lever  60  closely contacted, and the lower surface of the tilt lever  60  and the upper surface of the tilt bracket  40  are closely contacted, when the bolt  61   a  is strongly tightened, when the tilt lever  60  is rotated, a friction force is increased, so that it is difficult to handle. In addition, the bolt is too loosely tightened, a noise occurs, and the bolt  61   a  is gradually loosened. 
   Fourth, there are problems in the capsule  80  adapted to fix the mounting bracket  70  to a vehicle body and a structure for assembling the capsule. 
   In the mounting bracket  70 , an intermediate portion of the same surrounds the upper side of the steering column  10 , and an expanding portion  71  is formed in extended both sides and is opposite to the vehicle body. A slot  42  which is opened in the upper side is formed in the expanding portion  71 . In addition, the capsule  80  is formed by injecting aluminum. An insertion groove  81  is formed in both sides in order for an outer surface of the slot  72  to be inserted thereinto. A bolt hole  82  is formed in the center, so that the bolt  84  passes through the same and is fixed to the vehicle body. 
   As shown in  FIG. 3 , a plurality of capsule holes  83  and slot holes  73  which pass through the upper and lower sides are formed in the engaged outer surfaces of the capsule  80  and the slot  72 . A plastic melting material is injected in the interior of the same for thereby hardening the same and forming a pin shape. 
   Namely, the hardened plastic melting material connects the capsule  80  fixed to the vehicle body and the mounting bracket  70  fixed to the steering column  10 . When an external impact is applied to the steering column  10 , the plastic melting material is broken, so that the steering column  10  is separated from the capsule  80 . 
   However, in the escaping apparatus of a conventional steering column, the capsule and the basic structure of the mounting bracket engaged thereto are complicated. In addition, a complicated process for injecting a plastic melting material and hardening the same in the slot hole communicating with the capsule hole formed in the capsule is needed. Therefore, the installation process is complicated, and the fabrication cost is increased. 
   Furthermore, when managing the weights using a fixing pin formed of plastic, since the weight managing limit is low based on the property of the material, the applicable range is limited. In order to overcome the above problems, when the number and thickness of the fixing pin are adjusted, the structure may be more complicated. 
   Fifth, there is a problem in the impact absorbing structure formed of the steering column  10  and the lower bracket  90  adapted to support the lower portion of the steering column. 
   The important points of the impact absorbing structure are that a lower bracket should be used for fixing the lower portion of the column to the vehicle body. Since the lower bracket of the lower portion of the column is integrally welded, an additional inner tube must be used for implementing an impact absorbing structure. In addition, the lower bracket must be welded to the lower portion of the inner tube. 
     FIG. 1  is a view illustrating the conventional impact absorbing structure. 
   Namely, a collapsing problem occurs between the outer tube  10   a  which surrounds the steering shaft  20  and the inner tube  10   b  fixed to the lower bracket for thereby absorbing an impact energy when a vehicle collides. The inner tube  10   b  is fixed to the vehicle body by the lower bracket  90 , and one end of the same is engaged to an inner surface of the outer tube  10   a . A plurality of curling portions  10   c  are formed along an outer circumference in the inner surface of the outer tube  10   a.    
   In particular, the above formation of the curling potion  10   c  is performed in such a manner that the portions remaining piercing operations are formed in the outer tube  10   a  are inwardly rolled. The above curling portion  10   c  is assembled to the end portion of the inner tube  10   b  for thereby implementing a friction force. 
   Therefore, when an impact energy is applied through the steering shaft  20  when a vehicle collides, the end portion of the inner tube  10   b  of the lower mounting portion makes a friction with the curling portion  10   c  of the outer tube  10   a , so that a collapsing operation is performed for thereby absorbing the impact energy. 
   However, in the above structure, when the outer tube  10   a  and the inner tube  10   b  are assembled, the curling portion  10   c  may be broken based on the material for thereby causing an error product. In particular, the process for forming the curling portion  10   b  in the outer tube  10   a  is very complicated. In addition, the inner tube must be added. Therefore, the number of parts is increased. 
   SUMMARY OF THE INVENTION 
   Accordingly, it is an object of the present invention to provide a steering tilt column assembly for a vehicle which overcomes the problems encountered in the conventional art. 
   It is another object of the present invention to provide a steering tilt column assembly for a vehicle which is capable of implementing a stable engagement of a fixing gear and a driving gear for obtaining a desired tilting state by providing a guard portion in an upper portion of a tilt bracket and a wedge in a lower portion of the guard portion for thereby enhancing a stability of a tilting state. 
   It is further another object of the present invention to provide a steering tilt column assembly for a vehicle which is capable of removing a conventional rotation member and increasing a productivity and decreasing a fabrication cost by directly performing an upward rotation operation of a driving gear using a tilt lever and increasing a productivity and decreasing a fabrication cost. 
   It is still further another object of the present invention to provide a steering tilt column assembly for a vehicle which is capable of preventing an engaging force of a bolt from affecting a rotation friction when a tilt lever is rotated by using a bolt having a step straight line portion for a bolt of a lever hinge portion of a tilt lever and preventing a noise in a tilt lever and a bolt from being loosened. 
   It is still further another object of the present invention to provide a steering tilt column assembly for a vehicle which is capable of implementing an easier fabrication and lower price by improving a material and structure of an initial impact absorbing capsule used in a mounting bracket and implementing a desired impact absorption based on only friction force between the capsule and a mounting bracket. 
   It is still further another object of the present invention to provide a steering tilt column assembly for a vehicle which is capable of implementing a stable engagement and a desired impact absorption when an impact is applied by providing an engaging structure of a lower portion of a column and a lower bracket having a cross section with a decreased diameter. 
   To achieve the above objects, in a steering column which includes a steering shaft which includes an upper side shaft and a lower side shaft connected with a universal joint in their lower and upper ends, an upper unit which is formed of an upper side tube which includes a steering shaft and surrounds a surrounding portion of the upper side shaft, a tilt bracket connected with the upper side tube, and a shroud bracket for fixing the above elements to a vehicle body, and a lower unit which is formed of a lower side tube which surrounds a surrounding portion of the lower side shaft, a column bracket which is connected with an upper end of the lower side tube and has a capsule assembling slot in left and right wing portions, and a lower mounting bracket adapted to fix a lower end of the lower side tube to a vehicle body, wherein hinge pin holes formed in left and right sides of the tilt bracket and hinge pin holes formed in left and right sides of the column bracket are engaged using a hinge pin, so that the upper unit including the upper side shaft is bent at a certain angle about the hinge pin with respect to the lower unit including the lower side shaft, there is provided a steering tilt column assembly for a vehicle which includes a tilting adjusting unit which includes a fixing gear and a driving gear between the column bracket and the tilt bracket, the tilting adjusting unit including a fixing gear which is fixed to an upper surface of the column bracket and has a threaded portion in an upper side surface, a driving gear in which a threaded portion of a lower surface is engaged to a threaded portion of the fixing gear, and a protrusion is formed in the upper surface of the same, the driving gear being rotatable on the tilt bracket, a wedge member which has a wedge portion in a lower surface for pressing the protrusion of the driving gear and has a connection protrusion in a lower surface of the front end, a tilt lever which is formed of an engaging hole into which a connection protrusion of the wedge member is inserted, and a hinge hole which is rotatable on the tilt bracket by inserting a hinge bolt, a handle portion extended from one end of the horizontal portion, and an extended portion which is connected with the other end of the horizontal portion and has an inclination portion for lifting up a side surface protrusion of the driving gear, a spring for pulling the wedge member and the tilt lever in a certain direction, and an extension spring adapted to return the tilt lever to an original position when the tilt lever is rotated. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become better understood with reference to the accompanying drawings which are given only by way of illustration and thus are not limitative of the present invention, wherein; 
       FIG. 1  is a perspective view illustrating a conventional steering column assembly; 
       FIG. 2  is a perspective view illustrating a tilting structure of a conventional steering column; 
       FIG. 3  is a perspective view illustrating a conventional capsule and assembled state; 
       FIG. 4  is a cross sectional view illustrating a structure of a conventional hinge bolt; 
       FIG. 5  is a perspective view illustrating the whole construction of a steering tilt column assembly for a vehicle according to the present invention; 
       FIG. 6  is a plan view illustrating the whole construction of a steering tilt column assembly for a vehicle according the present invention; 
       FIG. 7  is a bottom view illustrating the whole construction of the present invention; 
       FIG. 8  is a front cross sectional view illustrating the whole construction of a steering tilt column assembly for a vehicle according to the present invention; 
       FIG. 9  is a disassembled perspective view illustrating the construction of major elements of a tilting adjusting unit according to the present invention; 
       FIG. 10  is a plan view illustrating an operation state of a tilting adjusting unit according to the present invention; 
       FIG. 11  is a front cross sectional view illustrating an operational state of a tilting adjusting unit according to the present invention; 
       FIG. 12  is a cross sectional view illustrating a hinge portion of a tilt lever according to the present invention; 
       FIG. 13  is a cross sectional view illustrating a hinge portion of a tilt lever according to another embodiment of the present invention; 
       FIG. 14  is a view illustrating the construction of an initial impact absorbing unit according to the present invention; 
       FIG. 15  is a cross sectional view illustrating a capsule and assembled state according to the present invention; 
       FIG. 16  is a cross sectional view illustrating a capsule mounting groove according to another embodiment of the present invention; 
       FIG. 17  is a cross sectional view illustrating a capsule according to the present invention; 
       FIG. 18  is a view illustrating the construction of a lower side impact absorbing unit according to the present invention; 
       FIG. 19  is a cross sectional view illustrating an assembled state of a lower side impact absorbing unit according to the present invention; and 
       FIG. 20  is a view illustrating the construction of a lower side impact absorbing unit according to another embodiment of the present invention. 
   

   DESCRIPTIONS OF REFERENCE NUMERALS OF MAJOR ELEMENTS OF THE DRAWINGS 
   
       
         100 : steering shaft 
         101 : upper side shaft 
         102 : lower side shaft 
         103 : universal joint 
         200 : steering column 
         201 : hinge pin 
         210 : upper unit 
         211 : upper side tube 
         212 : tilt bracket 
         213 : shroud bracket 
         220 : lower unit 
         221 : lower side tube 
         222 : column bracket 
         223 : lower mounting bracket 
         230 : tension spring 
         300 : tilting adjusting unit 
         310 : fixing gear 
         311 : threaded portion 
         320 : driving gear 
         321 : threaded portion 
         323 : protrusion 
         324 : side surface protrusion 
         325 : shaft pin 
         330 : wedge member 
         331 : wedge portion 
         332 : connection protrusion 
         340 : tilt lever 
         341 : handle 
         342 : horizontal portion 
         343 : lever hinge hole 
         344 : engaging hole 
         345 : extended portion 
         346 : inclination portion 
         347 : hinge bolt 
         350 : spring 
         400 : initial impact absorbing unit 
         410 : capsule 
         411 : upper plate 
         412 : lower plate 
         413 : protrusion 
         414 : electric portion 
         415 : bolt hole 
         500 : lower side impact absorbing unit 
     
  
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The construction and operation of the present invention will be described with reference to the accompanying drawings. 
     FIG. 5  is a perspective view illustrating the whole construction of a steering tilt column assembly for a vehicle according to the present invention,  FIG. 6  is a plan view illustrating the whole construction of a steering tilt column assembly for a vehicle according the present invention, and  FIG. 7  is a bottom view illustrating the whole construction of the present invention. 
   As shown therein, a steering tilt column assembly according to the present invention includes a steering shaft  100  which is formed of an upper side shaft  101  and a lower side shaft  102  connected by a universal joint  103  in their lower and upper portions, an upper side tube  211  which includes the steering shaft  100  and surrounds the surrounding portion of the upper side shaft  101 , a tilt bracket  212  connected to the upper side tube, an upper unit  210  which includes a shroud bracket  213  for fixing the above elements to a vehicle body, a lower side tube  221  which surrounds the surrounding portion of the lower side shaft  102 , a column bracket  222  which has a capsule assembling slot  222   b  in a left and right wing portion  222   a  in a connected state to an upper portion of the lower side tube, and a lower unit  220  which includes a low mounting bracket  223  for fixing a lower portion of the lower side tube  221  to a vehicle body. 
   Therefore, a tilting operation is implemented by connecting a hinge pin hole  212   b  formed in left and right sides of the tilt bracket  212  and a hinge pin hole  212   b  formed in left and right sides of the column bracket  222  using a hinge pin  201 . 
   Namely, as shown in  FIG. 7 , the upper unit  210  which includes the upper side shaft  101  with respect to the lower unit  220  including the lower side shaft  102  is bent at a certain angle about the hinge pin  201 . The tilting adjusting unit  300  according to the present invention adapted to implement the above tilting operation will be described with reference to FIG.  9 . 
   There are provided a fixing gear  310  which is fixed to an upper surface of the column bracket  222  and has a threaded potion  311  in the upper surface of the same, a driving gear  320  which has a protrusion  323  of the upper surface and is rotatable on the tilt bracket  212  and is constructed in such a manner that the threaded portion  321  of the lower surface is engaged to the threaded portion of the fixing gear, and a wedge member  330  which has a wedge portion  331  adapted to press the protrusion  323  of the driving gear  320  and a connection protrusion  332  in the lower surface of the front end. 
   At this time, the fixing gear  310  is fixed in a conventional manner using an engaging bolt. The driving gear  320  is upwardly and downwardly rotatable by inserting the rear end of the same between the hinge support ribs  212   e  protruded from both sides of the upper surface of the tilt bracket  212 , and the shaft pin  325  passes through in a horizontal direction. 
   In the tilt bracket  212  according to the present invention, as an important element, the guard portion  212   d  which is formed across both sides in the portion higher than the hinge support ribs  212   e  protruded for installing the driving gear is provided, so that it is possible to press the upper surface of the wedge member  330 . 
   The wedge member  330  and the driving gear  320  positioned in the lower portion of the guard portion  212   d  are operated by the tilt lever  340 . 
   The tilt lever  340  includes a horizontal portion  342  which has a hinge hole  343  for a rotatable engagement on the tilt bracket  212  by inserting the engaging hole  344  into which the connection protrusion  332  of the wedge member  330  is inserted and the hinge bolt  347 , a handle  341  which is extended from one side end of the horizontal portion  342 , an extended portion  345  extended from the other side of the horizontal portion  342 , and an inclination portion  346  which is inclined for lifting the side surface protrusion  324  of the driving gear  320 . 
   In addition, as shown in  FIG. 12 , the tilt lever  340  is engaged by the hinge bolt  347  for thereby implementing a stable rotation. 
   The hinge bolt  347  which has a hinge point obtained by inserting the same into the hinge hole  343  of the horizontal portion  342  of the tilt lever  340  is engaged based on a straight line portion  347   a  in the lower portion of the bolt head. 
   The straight line portion  347   a  has a diameter D larger than the diameter of the screw portion of the bolt and a length L longer than the thickness of the horizontal portion  342  or a (+) tolerance. Therefore, when engaged using the hinge bolt  347 , since the horizontal portion  342  is not pressed by the bolt head, the horizontal portion  342  does not have a friction resistance. 
   At this time, as shown in  FIG. 13 , the hinge bolt  347  according to the present invention may be implemented in another embodiment of the present invention. Namely, as shown in  FIG. 13 , an expanding hole  222   f  is formed in an upper portion of the threaded hole  222   a  to which the hinge bolt  347  is engaged, and a part of the straight line portion  347   a  of the hinge bolt  347  is inserted into the expanding hole  222   f . At this time, the length L of the straight line portion  347   a  is the size that the depth d of the expanding hole  222   f  is added with the thickness of the horizontal portion  342 . The allowable tolerance is (+), not (−). 
   In addition, the above engagement is performed for the reason that it is possible to prevent a movement of the hinge bolt  347  and increase the engaging force. 
   In addition, a tension spring  230  is connected between the wedge member  330  and the shroud bracket  213  for pulling the wedge member  330  in one direction. A tension spring  230  is connected between the tilt lever  340  and the shroud bracket  213  for returning the tilt lever  340  to its original position when the same is rotated. 
   In the present invention, an initial impact absorbing unit  400  is provided for fixing the column bracket  222  to the vehicle body. 
   Namely, as shown in  FIG. 14 , in the initial impact absorbing unit  400 , the capsule  410  includes an upper plate  411  having a plurality of protrusions  413  in the lower surface, a lower plate  412  which has a plurality of protrusions  413  in the upper surface, and an elastic portion  414  which integrally connects one side of the upper plate and one side of the lower plate. 
   In addition, as shown in  FIG. 17 , the capsule  410  has a certain width W between the end surface of the support member  461   a  of the upper plate  411  and the end surface of the support member  416   b  of the lower plate  412  when the upper plate  411  and the lower plate  412  are parallel. The above width W is smaller than a height H of the protrusions  413  formed in the upper plate  411  and the lower plate  412 . 
   The width W is provided for preventing the protrusions of the upper plate  411  and the lower plate  412  from being broken due to an over engaging force of the bolt when the engaging bolt is inserted through the bolt hole  415  and is engaged to the vehicle body. 
   If the protrusions  413  of the upper plate  411  and the lower plate  412  are all broken and are engaged due to an over engaging force of the engaging bolt, the capsule  410  and the wing portions  222   a  of the column bracket  222  are not escaped from each other when an impact occurs, so that it is impossible to implement a desired impact absorbing function. 
   In addition, as shown in  FIG. 14 , the column bracket  222  of the present invention for using the capsule  410  includes a mounting groove  222   c  for mounting the capsule  410  therein in the surrounding portion of the slot  222   b  of the wing portion  222   a , and the capsule  410  is inserted into the mounting groove  222   c.    
   As show in  FIG. 15 , the through holes  222   d  corresponding to the position of the protrusions  413  of the capsule  410  are formed in the mounting groove  222   c . Therefore, it is possible to engage the capsule in a state that the protrusions  413  are in the through holes  222   d  as shown in FIG.  17 . In addition, as shown in  FIG. 17 , the through holes  222   d  may not be formed. 
   In the present invention, a lower side impact absorbing unit  500  is provided between the lower side tube  221  and the lower mounting bracket  223 . 
   As shown in  FIG. 18 , a flat surface  221   a  is formed in an end portion of the lower side tube  221  based on a decrease of the outer diameter, and the lower mounting bracket  223  has an insertion hole  223   a  having a straight line inner diameter portion  223   b  to be matched with a cross section shape of the end portion in which the flat surface of the lower side tube is formed. 
   Therefore, when an impact occurs in the longitudinal direction of the column, the straight line inner diameter portion  223   b  of the insertion hole  223   a  goes into the cylindrical portion after the flat surface  221   a . In this state, a friction force is increased for thereby absorbing the impact based on the friction force. 
   At this time, as shown in  FIG. 19 , the lower mounting bracket  223  may has an inner extended portion  223   c  formed by extending the inner circumference of the insertion hole  223   a  and bending the same in a certain direction for thereby enhancing a friction force. 
   In addition, The straight inner diameter portion  223   b  formed in the flat surface  221   a  of the end portion of the lower side tube  221  and the insertion hole  223   a  of the low mounting bracket  223  may be provided in multiple numbers at other positions as shown in FIG.  20 . 
   The above construction is provided for maintaining a certain gap and preventing the initial friction inertia force from being maximized. 
   In  FIG. 5 , the reference numeral  600  represents a stopper unit for limiting the bending angles of the upper and lower directions of the tilt bracket  212 . 
   The operations and operation states of the present invention will be described. 
   First, when adjusting the angle of the steering wheel by a driver, the handle  341  of the tilt lever  340  is pulled. 
   When the horizontal portion  342  of the tilt lever  340  is rotated about the hinge bolt  347 , the inclination portion  346  formed in the extended portion  345  of the other side end pushes upwardly the side surface protrusion  324  protruded from the side of the driving gear  320  and pulls the wedge member  330  engaged with the protrusion  332  connected with the engaging hole  344  of the horizontal portion  342 . 
   Therefore, since the lower surface wedge  331  of the wedge member  330  is distanced from the protrusion  323  of the upper surface of the driving gear  320 , the driving gear  320  is lifted up, and the threaded portion  321  of the driving gear  320  which is lifted up is distanced from the threaded portion  311  of the fixing gear  310 . 
   When the threaded portion  311  of the fixing gear  310  is distanced from the threaded portion  321  of the driving gear  320 , as shown in  FIG. 7 , the upper side shaft  101  and the tilt bracket  212  and the upper unit  210  including a part of the tilting adjusting unit  300  may be upwardly rotated and lifted up about the hinge pin  201  which is a tilt hinge point or may be downwardly rotated. 
   In a state that the tilt lever  340  is pulled, when the upper unit is in a desired position by upwardly and downwardly adjusting the same, in the above state, the tilt lever  340  is placed down. 
   At the moment when the tilt lever  340  is placed down, the tilt lever  340  is returned by a force of the tilt lever returning spring  350 , and when the tilt lever is returned, the horizontal portion  342  and the extended portion  345  of the other end are returned. In addition, the above operation is implemented in such a manner that the wedge member  330  in which the connection protrusion  332  is engaged to the engaging hole  344  of the horizontal portion  342  is pulled. 
   The wedge member  330  is downwardly rotated by downwardly pressing the protrusion  323  of the upper surface of the driving gear  320  using the wedge portion  331  of the lower surface. At this time, the inclination portion  346  of the retracted extended portion  345  allows the side surface protrusion  324  of the driving gear  320  to be downwardly moved. 
   Therefore, the wedge member  330  returning by the spring  350  is inserted between the guard portion  212   d  formed in the upper portion of the tilt bracket  212  and the protrusion  323  of the upper surface of the driving gear  320 . Since the wedge portion  331  of the wedge member  330  presses the protrusion  323  of the upper surface of the driving gear  320 , the driving gear  320  is downwardly pressed, and the threaded portion  321  of the driving gear  320  is engaged with the threaded portion  311  of the fixing gear  310  for thereby completing a tilting adjustment. 
   In the steering tilt assembly according to the present invention, when an impact is applied in the longitudinal direction of the shaft, the initial impact absorbing unit  400  is first operated, and at the same time the impact absorbing unit  500  of the lower side of the lower side tube is operated for thereby absorbing the impact. 
   First, in the initial impact absorbing unit  400 , the left and right wing portions  222   a  of the column bracket  222  are escaped from the capsule  410  fixed to the vehicle body by a bolt based on a certain friction force. 
   Namely, since the protrusions  413  inwardly protruded from the upper plate  411  and the lower plate  412  of the capsule  410  are engaged before the same are fully pressed, the impact is absorbed based on a friction force of the protrusions. As shown in  FIG. 15 , in the case that a part of each protrusion  413  is inserted into the through hole  222   d , since a friction force is larger, the initial impact absorbing force is large. 
   In addition, in the lower side impact absorbing unit  500 , in a state that the straight line inner diameter portion  223   b  of the insertion hole  223   a  of the lower mounting bracket  223  is force-fit into the flat surface  221   a  of the end portion of the lower side tube  221 , when an impact occurs, the straight line inner diameter portion  223   b  of the insertion hole  223   a  is distanced from the flat surface  221   a  and goes to the cylindrical portion. Therefore, since the same must overcome the change of the outer diameter and must advance, it is possible to absorb the impact. 
   As described above, in the present invention, since there are provided a wedge member adapted to press the driving gear in the upper portion of the tilt bracket and a guard portion adapted to press the wedge member, it is possible to implement a stable engaged state of the fixing gear and the driving gear for continuously implementing a certain tilting state. In addition, it is possible to enhance a stability of the tilting state. 
   In addition, in the present invention, since the upward rotation of the driving gear is directly operated by the tilt lever, it is possible to remove the part of the conventional rotation member. Therefore, it is possible to enhance the productivity and decrease the fabrication cost. 
   In addition, when rotatably engaging the tilt lever, since as the lever hinge bolt, the bolt having a straight line portion is used, the engaging force of the bolt does not affect the rotation friction of the horizontal portion when the tilt lever is rotated. Therefore, it is possible to prevent a noise in the tilt lever and prevent a bolt from being loosened. 
   In addition, since the capsule for the initial impact absorbing unit is formed of a metallic material without using a synthetic resin material, and there is provided a structure with protrusions, it is possible to implement an easier fabrication, and the price is low, and it is possible to implement an initial impact absorption based on only the friction force between the capsule and the mounting bracket. 
   In addition, since an engaging structure of the lower portion of the column and the lower bracket has a cross section portion with a decreased diameter and is directly engaged to the vehicle body through the lower bracket, it is possible to implement an impact absorbing unit without an additional inner tube inserted into the lower side of the lower side tube like the conventional art. 
   As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described examples are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.