Abstract:
A shift lever device includes a housing fixed to a vehicle body, and a shift lever swingably supported on the housing. The shift lever includes a tubular member, a rod disposed in the tubular member and having a spring support portion at an axially intermediate part thereof, a spring support sleeve fixedly disposed in the tubular member and having a spring support surface at a lower end thereof, and a spring placed around the rod and between the spring support portion of the rod and the spring support surface of the spring support sleeve so as to urge the rod to lockingly engage at a lower end with the housing.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a shift lever device for an automatic transmission of a vehicle and more particularly to a shift lever device having a rod axially movable for engagement with or disengagement from a stationary housing and a spring for urging the rod to lockingly engage the housing.  
         [0002]     In recent years, an automatic transmission capable of changing a gear ratio automatically is widely used in automotive vehicles. There are two types of shift lever devices for changing a shift range of a shift lever for such an automatic transmission, i.e., a pull-rod type for changing the range under a condition where a rod axially movable for engagement with or disengagement from a stationary housing is pulled-up by pushing a knob button and a push-rod type for changing the range under a condition where the rod is pushed down by pushing the knob button.  
         [0003]     An example of a pull-rod type shift lever device is disclosed in Unexamined Japanese Patent Publication No. 2002-283866.  FIGS. 8A and 8B  show a knob and its adjacent portion of such a pull-rod type shift lever device. Into a knob  101  is inserted a metallic pipe  102 . The knob  101  has an integral resin pipe  103  disposed around the metallic pipe  102 . Namely, the knob  101  and the metallic pipe  102  are joined together at a portion “A”. Into the metallic pipe  102  is inserted a rod  104  of a nearly cruciform section, and to an upper end of the rod  104  is connected a connecting portion  105   c  of a pull block  105 . The pull block  105  is movable along a vertical guide hole (no numeral) of the knob  101  and has an upward inclined surface  105   a  and a downward inclined surface  105   b.  On the other hand, a knob button  106  is provided so as to be movable along a horizontal guide hole (no numeral) of the knob  101 . The knob button  106  has a downward inclined surface  106   a  and an upward inclined surface  106   b.  The rod  104  has a spring support portion  104   a  of an increased outer diameter. A spring  107  is disposed between the spring support portion  104   a  and a stepped portion downward surface  101   e  of the knob  101  for urging the rod  104  downward.  
         [0004]     The rod  104  is urged downward by the spring  107 . When the knob button  106  is pushed into the knob  101 , the pull block  105  is pulled upward against the bias of the spring  107  to make the shift lever swingable.  
         [0005]     Since the spring  107  is accommodated in the metallic pipe  102 , it is desired that the inner diameter of the stepped portion downward surface  101   e  is small. On the other hand, since the knob  101  needs be formed with a space for accommodating the connecting portion  105   c  of the pull rod  105  at the same place where the stepped portion down surface  101   e  is formed, there are restrictions on the size of the stepped portion lower surface  101   e  such that the inner diameter of the stepped portion lower surface  101   e  cannot be sufficiently small. The width “b” of the connecting portion  105   c  of the pull bock  105  shown in  FIG. 8B  is thus determined based on agreement between the above-described conflicting matters, resulting in that the area of the stepped portion downward surface  101   e  is not sufficiently large.  
       SUMMARY OF THE INVENTION  
       [0006]     Since the stepped portion downward surface  101   e  that serves as a spring support surface is provided to the knob  101 , it cannot be checked whether the spring  107  functions properly unless the knob  101  is installed in place on the metallic pipe  102 . Namely, while it can be checked at the time of assembly in a part maker for making the shift lever device whether the spring  107  functions properly under a condition where a tentative knob  101  is installed in place on the metallic pipe  102 , a new drawback of the spring  107  may possibly be caused when a knob is actually installed at the time of assembly in a car maker after shipping since the area of the stepped portion downward surface  101   e  is not sufficiently large.  
         [0007]     It is accordingly an object of the present invention to provide a shift lever device which is free from the above-noted problem.  
         [0008]     According to an aspect of the present invention, there is provided a shift lever device comprising a housing, and a shift lever swingably supported on the housing, the shift lever including a tubular member having a recessed portion at an inner circumferential surface, a rod axially movably disposed in the tubular member and having a spring support portion, a spring placed around the rod and abuttingly engaged at one of opposite ends with the spring support portion so as to urge the rod to lockingly engage at a lower end with the housing, a knob connected to an end of the tubular member, a knob button movably installed on the knob and operatively connected to the rod to cause, when pushed, the rod to be pulled upward against the bias of the spring thereby disengaging the rod from the housing to make the shift lever swingable, and a spring support sleeve disposed within the tubular member for supporting the other of the opposite ends of the spring, the spring support sleeve having at an outer circumferential surface a projection that is engaged in the recessed portion of the tubular member.  
         [0009]     According to another aspect of the present invention, there is provided a shift lever device for an automatic transmission of a vehicle comprising a housing fixed to a vehicle body, and a shift lever swingably mounted on the housing, the shift lever including a tubular member, a rod axially movably disposed in the tubular member and having a spring support portion at an axially intermediate part thereof, a spring support sleeve fixedly disposed in the tubular member and having a spring support surface at a lower end thereof, a spring placed around the rod and between the spring support portion of the rod and the spring support surface of the spring support sleeve so as to urge the rod to lockingly engage at a lower end with the housing. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIGS. 1A and 1B  show principal portions of a shift lever device according to a first embodiment of the present invention, wherein  FIG. 1A  is a front sectional view and  FIG. 1B  is a side sectional view;  
         [0011]      FIG. 2  is a perspective view of a pull rod and a rod employed in the shift lever device of the first embodiment;  
         [0012]      FIGS. 3A, 3B  and  3 C show a spring support sleeve employed in the shift lever device of the first embodiment, wherein  FIG. 3A  is a plan view,  FIG. 3B  is a front sectional view and  FIG. 3C  is a side sectional view;  
         [0013]      FIGS. 4A and 4B  are sectional views for illustrating operations of the shift lever device of the first embodiment;  
         [0014]      FIG. 5  is an exploded perspective view of the shift lever device of the first embodiment;  
         [0015]      FIGS. 6A and 6B  are views similar to  FIGS. 1A and 1B , respectively but show a shift lever device according to a second embodiment;  
         [0016]      FIGS. 7A, 7B  and  7 C are views similar to  FIGS. 3A, 3B  and  3 C, respectively but show a spring support sleeve employed in the second embodiment; and  
         [0017]      FIGS. 8A and 8B  are views similar to  FIGS. 1A and 1B , respectively but show a prior art shift lever device. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]     Referring to  FIGS. 1A, 1B  and  2  to  5  inclusive, a shift lever device according to a first embodiment of the present invention will be described.  
         [0019]     As shown in  FIGS. 4A and 4B , the shift lever device includes a housing  12  and a shift lever  11  swingably mounted on the housing  12 .  
         [0020]     The shift lever  11  includes a shift lever base  13  swingably supported on the housing  12 , a shift lever main body  14  mounted on the base  13  and a knob  1  mounted on an upper end portion of the shift lever main body  14 .  
         [0021]     The shift lever base  13  has at a lower end portion thereof an integral shaft  13   a  protruding horizontally therefrom in the opposite directions. The shaft  13   a  is rotatably supported by a pair of bearing portions  12   a  of the housing  12 .  
         [0022]     The shift lever main body  14  includes a metallic pipe or tubular member  2  and a resin pipe  3  covering the tubular member  2  and formed integral with the knob  1 . A rod  4  made of resin is inserted into the tubular member  2  from the lower side of the shift lever base  13 .  
         [0023]     The knob  1  has a pull block  5  that is movable upward and downward along a first vertical guide hole  1   a.  Further, above the first guide hole  1   a  is formed a second guide hole  1   b  in a way as to extend horizontally in the direction to cross the first guide hole  1   a  at right angles. Slidably disposed within the second guide hole  1   b  is a knob button  6 . A conversion means is provided for converting movement of the knob button  6  into vertical movement of the pull block  5 . Namely, the pull block  5  has a pair of parallel upward and downward inclined surfaces, i.e., an upward inclined surface  5   a  and a downward inclined surface  5   b.  The knob button  6  has a downward inclined surface  6   a  and an upward inclined surface  6   b  which are in sliding contact with the upward and downward inclined surfaces  5   a  and  5   b,  respectively. Further, the knob button  6  has at an end portion an axial accommodation hole (no numeral), and between a bottom surface of the axial accommodation hole and a bottom surface of the second guide hole  1   b  is disposed a spring  19  for urging the knob button  6  outward.  
         [0024]     As shown in  FIG. 1A , the knob  1  is connected to an upper end portion of the tubular member  2  at a first connecting portion  21 . To prevent relative rotation between the knob  1  and the tubular member  2 , the upper end portion of the tubular member  2  has a plurality of axial slits  2   a  that are arranged in a circumferential direction, in which axial slits  2   a  are engaged protrusions  1   c  formed at the inner circumferential surface of the guide hole  1   a  of the knob  1 .  
         [0025]     An upper end of the rod  4  inserted into the tubular member  2  is connected to the pull block  5  at a second connecting portion  22 . The structure of the second connecting portion  22  will be described below. As shown in  FIG. 2 , the pull block  5  has at a lower part thereof an integral connection portion  5   c.  The connection portion  5   c  has a pair of hooks  5   d,  whereas the rod  4  has at an upper end thereof a head portion  4   c  formed with a pair of shelf-like engagement sections  4   b.  When the head portion  4   c  is placed between the pair of hooks  5   d  through movement in the direction perpendicular to the axis of the head portion  4   c,  the pair of shelf-like engagement sections  4   b  are engaged with the pair of hooks  5   d  such that the head portion  4   c  is held between the hooks  5   d  to allow the rod and the pull block  5  to move as an integral unit.  
         [0026]     The structure for urging the rod  4  downward will be described. The rod  4  has a spring support portion  4   a  that is a portion increased in outer diameter. A spring  7  for urging the spring support portion  4   a  toward a base end portion of the shift lever  11  is disposed so as to surround the rod  4 . For supporting the upper end of the spring  7 , a spring support sleeve  20  is disposed inside the tubular member  2 .  
         [0027]     The spring support sleeve  20  is shown in an enlarged scale in  FIGS. 3A  to  3 C. The spring support sleeve  20  is nearly hollow cylindrical and has a spring support surface  20   a  at a lower end. The spring support sleeve  20  has a pair of protrusions  20   b  for preventing movement thereof relative to the tubular member  2 . The projections  20   b  are located closer to the knob  1 , more specifically, closer to an upper part of the knob than the spring support surface  20   a  and at positions diametrically opposite to each other. On the other hand, the tubular member  2  has at the corresponding positions to the projections  20   b  a pair of recessed portions or holes  2   b  in which the projections  20   b  are fitted. For the purpose of making the spring support sleeve  20  be flexible or elastically deformable so that the spring support sleeve  20  can be inserted into the tubular member  2 , the spring support sleeve  20  has four axial slits  20   c  arranged in the circumferential direction. Further, in order that the projections  20   b  can be inserted into the tubular member  2  with ease when the spring support sleeve  20  is pushed into the tubular member  2  while being elastically deformed, the projections  20   b  has a slanting lower surface  20   d.  Further, in order that the projections  20   b  are guided by the slits  2   a  into the holes  2   b  when the spring support sleeve  20  is inserted into the tubular member  2 , the slits  2   a  of the tubular member  2  are disposed closer to the knob  1 , more specifically, closer to an upper part of the knob  1  than the holes  2   b  and at circumferentially the same positions as the holes  2   b.    
         [0028]     The shift lever base  13  has a guide hole  13   b  for guiding up-and-down movement of the rod  4 . To a lower end of the rod  4 , which protrudes downward from the guide hole  13   b  is provided an operation portion  15 . The operation portion  15  has a wedge-shaped groove at a lower side so as to form a detent engagement section  16  at a slanting surface of the wedge-shaped groove. On the other hand, the housing  12  has at a central portion thereof an integral detent plate  17  protruding upward. The detent plate  17  has a plurality of detent grooves  18  formed along an upper end thereof.  
         [0029]     The detent grooves  18  includes a P range groove for parking, R range groove, N range groove, D range groove, 2 range groove and 1 range groove that are arranged adjacently one after another. An indicator cover (not shown) having an indication of the P range, etc. is disposed at an upper portion of the housing  12 .  
         [0030]     By pushing the knob button  6  against the bias of the springs  7  and  19  and thereby pulling the rod  4  upward by way of the upward inclined surface  6   b  and the downward inclined surface  5   b,  the detent engagement section  16  is disengaged from the detent grooves  18 . This makes the shift lever  11  movable or swingable relative to the housing  12  for selection of the ranges.  
         [0031]     Then, assembly of the shift lever device will be described. As seen from  FIG. 5 , the rod  4  is inserted into the guide hole  13   b  of the shift lever base  13  from the lower side thereof. When the upper end of the rod  4  protrudes upward from the tubular member  2 , the spring  7  is disposed within the tubular member  2  in a way as to surround the rod  4 . Then, the spring support sleeve  20  is inserted into the tubular member  2  while compressing the spring  7 . Thereupon, the protrusions  20   b  of the spring support sleeve  20  are brought into engagement with the holes  2   b  such that the spring support sleeve  20  is fixedly held within the tubular member  2 . Thereafter, the rod  4  is pushed upward to cause the head  4   c  to protrude from the upper end of the tubular member  2 . The head  4   c  of the rod  4  is placed between the pair of hooks  5   d  of the pull block  5  and engaged therewith through movement of the pull block  5  in the direction substantially perpendicular to the axis of the rod  4 , whereby the pull block  5  and the rod  4  are joined together at the second joining portion  22  (refer to  FIG. 1A ). Thereafter, the second joining portion  22  is pulled into the tubular member  2  under the bias of the spring  7  and stops when the pull block  5  is abuttingly engaged with the upper end of the tubular member  2 . After the shift lever  11  is swingably supported on the housing  12 , the knob  1  is attached to the shift lever  11 .  
         [0032]     Then, the operation of the shift lever device will be described. First, in case the shift lever  11  is positioned in, for example, the P range, the rod  4  is urged downward under the bias of the springs  7  and  19  as shown in  FIG. 4A , thus causing the detent engagement section  16  is engaged in the detent groove  18  for the P range.  
         [0033]     For moving the shift lever  11  from the P range to the D range, the knob button  6  is pushed. Namely, as shown in  FIG. 4B , the knob button  6  is pushed against the bias of the springs  7  and  19  and the pushing force is transmitted to the rod  4  by way of the upward inclined surface  6   b  and the downward inclined surface  5   b,  thus causing the rod  4  to be pulled upward and therefore causing the detent engagement section  16  to be disengaged from the detent groove  18 . Thereafter, the shift lever  11  is moved and the knob button  6  is released from being pushed. By this, the rod  4  is urged downward by the springs  7  and  19  and the detent engagement section  16  is engaged in the detent groove  18  for the D range.  
         [0034]     While only movement of the shift lever  11  from the P range to the D range has been described, movement of the shift lever  11  to other ranges can be attained by the similar operation as described above.  
         [0035]     Since according to the present invention the spring support sleeve  20  that supports the knob side end or upper end of the spring  7  is disposed within the metallic tube  2 , the knob side end of the spring  7  is assuredly supported by the spring support sleeve  20  irrespective of whether the knob  1  is attached to the end of the tubular member  2 . For this reason, the spring  7  can be tested for its operation before the knob  1  is attached to tubular member  2 , and therefore the shift lever device can be assured of its operation or performance.  
         [0036]     Further, since according to the present invention the projections  20   b  formed on the outer circumferential surface of the spring support sleeve  20  for engagement in the slits  2   a  formed in the tubular member  2  are disposed closer to the knob  1  than the spring support surface  20   a,  the spring support surface  20   a  can be larger and can support the spring  7  more assuredly.  
         [0037]     Further, according to the present invention, at the time of insertion of the spring support sleeve  20  into the tubular member  2 , the projections  20   a  are aligned with the slits  2   a  of the tubular member  2  and moved along the same. Insertion of the spring support sleeve  20  is continued after the projections  20   a  once run on the inner circumferential surface of the tubular member  2 , and then the projections  20   b  snap into engagement in the holes  2   b.  Namely, the slits  20   a  serve as guides for positioning the projections  20   b.  Thus, the projections  20   b  can be engaged in the holes  2   b  easily and assuredly, and therefore assembly of the shift lever device can be attained with an improved efficiency. The slits  2   a  also serve as a stopper for preventing rotation of the knob  1  relative to the tubular member  2 .  
         [0038]     Referring to  FIG. 6 , the second embodiment will be described. In  FIG. 6 , like reference numeral designate like parts to those of the first embodiment and repeated description thereto is omitted for brevity.  
         [0039]     In the second embodiment, a spring support sleeve  20 ′ shown in  FIG. 7  is used. As seen from  FIG. 7 , the spring support sleeve  20 ′ is larger in the overall length than that employed in the first embodiment. The spring support sleeve  20 ′ has at an outer circumferential surface a pair of projections  20   e  for preventing excessive insertion thereof into the tubular member  2 . The projections  20   e  are diametrically opposite to each and located on a plane that is perpendicular to the plane on which the projections  20   b  are located. The projections  20   e  are adapted to be moved along while being engaged in the slits  2   a  of the tubular member  2  upon insertion of the spring support sleeve  20 ′ into the tubular member  2  as shown in  FIG. 6B . The pair of holes  2   b  in which the pair of projections  20   b  are engaged differ in circumferential position by 90 degrees from those of the first embodiment, as will be understood from comparison of  FIGS. 1 and 6 .  
         [0040]     By the present invention, the spring support sleeve  20 ′ is moved into the tubular member  2 , with the projections  20   e  for preventing excessive insertion being circumferentially aligned with the respective slits  2   a  and moved along the same. Simultaneously with the projections  20   b  being engaged in the holes  2   b,  the projections  20   e  for preventing excessive insertion are abuttingly engaged with the inner ends of the slits  2   a  to prevent further insertion of the spring support sleeve  20 ′ into the tubular member  2 . Thus, occurrence of such a case in which excessive insertion of the spring support sleeve  20 ′ that is performed even after the projections  20   b  are engaged in the holes  2   b  and causes the projections  20   b  from being disengaged from the holes  2   b  can be assuredly prevented and the assembly of the shift lever device can be attained with an improved efficiency and assuredness.  
         [0041]     The entire contents of Japanese Patent Application P2005-120466 (filed Apr. 19, 2005) are incorporated herein by reference.  
         [0042]     Although the invention has been described above by reference to a certain embodiment of the invention, the invention is not limited to the embodiment described above. Modifications and variations of the embodiment described above will occur to those skilled in the art, in light of the above teachings. For example, while in the second embodiment it has been described and shown that the projections  20   e  for preventing excessive insertion differ in the circumferential position by 90 degrees from the projections  20   b  and the holes  2   b  differ in the circumferential position by 90 degrees from the slits  2   a,  the projections  20   e  and the projections  20   b  may be formed at the same circumferential positions.