Patent Publication Number: US-2007108859-A1

Title: Seat motors assembly

Description:
BACKGROUND OF INVENTION  
      The present invention relates to power adjustable seats in vehicles, and in particular to assemblies for seat motors in power adjustable seats.  
      Power adjustable seat systems for vehicles enjoy wide use today, with many including three separate motors to accomplish multiple seat adjustment functions. Some seat systems have motors that are spaced apart and oriented at different angles, while others include motors mounted side-by-side, parallel to each other. For either of these types of arrangements, the motors are typically each mounted in a relatively thick metal housing in order to meet electromagnetic interference requirements.  
      An example of a power seat system with parallel motors is described and shown in U.S. Pat. No. 6,857,612, incorporated herein by reference. In this patent, a seat drive mechanism is described that includes three parallel side-by-side bi-directional motors, each mounted in a separate metal motor housing. Each motor housing includes multiple metal tabs extending from its ends. During assembly of the power seat assembly, the motors are mounted in the housings. The housings and end caps are mounted in a jig, and a machine then bends the metal tabs down over features in motor end caps—permanently deforming the tabs to hold the assembly together. In order to remove an end cap for servicing, then, one must find a way to grip and hold the metal tabs with sufficient force to bend the tabs back to their original positions. This type of mounting and securing system has several drawbacks, however. For example, the need for the jig and machine to bend the tabs during initial assembly is more costly and time consuming than is desired. Also, the relative difficulty involved with disassembly is undesirable. In addition, mounting each motor in its own separate housing may be undesirable for certain power seat assemblies.  
     SUMMARY OF INVENTION  
      An embodiment of the present invention contemplates a seat motors assembly for use in a seat drive mechanism of a vehicle. The seat motors assembly may include a first motor housing having a first end with a first snap-in tab extending therefrom, and a second motor housing having a first end with a first snap-in tab extending therefrom. It may also include a first housing end cap including a first motor housing mounting wall operatively engaging the first end of the first motor housing and a first snap retention feature engaging with the first snap-in tab of the first motor housing to releasably secure the first motor housing to the first housing end cap, with the first housing end cap including a second motor housing mounting wall operatively engaging the first end of the second motor housing and a second snap retention feature engaging with the first snap-in tab of the second motor housing to releasably secure the second motor housing to the first housing end cap.  
      An embodiment of the present invention also contemplates a seat motors assembly for use in a seat drive mechanism of a vehicle. The seat motors assembly may include a motor housing having a first motor portion and a second motor portion, and a first end and an opposed second end; a first housing end cap mounted to the first end of the motor housing; and a second housing end cap mounted to the second end of the motor housing. It may also have a first snap retention feature included in one of the first housing end cap and the second housing end cap, and a first snap-in tab extending from the other of the first housing end cap and the second housing end cap and operatively engaging the first snap retention feature to releasably secure the first housing end cap to the second housing end cap.  
      An embodiment of the present invention also contemplates a seat motors assembly for use in a seat drive mechanism of a vehicle. The seat motors assembly may include a motor housing having a first end and an opposed second end, a first housing end cap mounted to the first end of the motor housing, and a second housing end cap mounted to the second end of the motor housing. It may also include a first snap retention feature on one of the first housing end cap and the motor housing, and a first snap-in tab on the other of the first housing end cap and the motor housing and operatively engaging the first snap retention feature to releasably secure the first housing end cap to the motor housing.  
      An advantage of an embodiment of the present invention is that the seat motors assembly can snap together and stay secured—without the need for jigs, additional tools or fasteners, machines for bending metal tabs or other secondary operations—during the assembly process. This may result in an overall cost savings for the seat motors assembly.  
      A further advantage of an embodiment of the present invention is that the seat motors assembly can be relatively easily disassembled for servicing. The motors can be removed by simple release of the snap-in tabs from snap retention features. Moreover, printed circuit boards that may be mounted in the assembly may be easily accessible through a quick release of a protective PCB assembly cover. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       FIG. 1  is a perspective view of a seat motors assembly, in accordance with a first embodiment of the present invention.  
       FIG. 2  is an exploded perspective view of the seat motors assembly of  FIG. 1 .  
       FIG. 3  is a perspective view of the first housing end cap of  FIG. 1 .  
       FIG. 4  is a perspective view of the second housing end cap of  FIG. 1 .  
       FIG. 5  is a sectional view of a top snap retention feature engaging a snap-in tab in accordance with the first embodiment of the invention.  
       FIG. 6  is a perspective view of a portion of a first housing end cap and a motor housing in accordance with a second embodiment of the present invention.  
       FIG. 7  is a perspective view of a portion of the motor housing shown in  FIG. 6 .  
       FIG. 8  is a perspective view of a portion of the first housing end cap shown in  FIG. 6 .  
       FIG. 9  is a perspective view of a seat motors assembly, in accordance with a third embodiment of the present invention.  
       FIG. 10  is an exploded perspective view of the seat motors assembly of  FIG. 9 .  
       FIG. 11  is a perspective view of a first housing end cap and an integral motor housing in accordance with the third embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION  
       FIGS. 1-5  illustrate a portion of a power adjustable seat system, indicated generally at  20 , employed with a vehicle (not shown). A seat motors assembly, indicated generally at  22 , forms a part of the seat system  20 . Other portions (not shown) of the power adjustable seat system  20  are known to those skilled in the art, and so will not be described in any detail herein.  
      The seat motors assembly  22  includes a first housing end cap  24  and a second housing end cap  26 . The first housing end cap  24  includes a main wall  28  having a first support rod mounting flange  30  and a second support rod mounting flange  32 . The first and second support rod mounting flanges  30 ,  32  are located to receive conventional support rods (not shown) that mount to seat structure in a known manner, and so will not be shown or discussed further herein. Extending from the main wall  28  are a first motor housing mounting wall  34 , a second motor housing mounting wall  36 , and a third motor housing mounting wall  38 . Each motor housing mounting wall  34 ,  36 ,  38  includes an alignment tab  40 . Also extending from the main wall  28 , coaxially located within each motor housing mounting wall  34 ,  36 ,  38 , are motor mounting flanges  42 . The motor mounting flanges  42  each receive an end of one of three motors (not shown). The motors may be, for example, bi-directional motors, which may, for example, operatively engage other portions of the power adjustable seat system  20  to provide horizontal, front vertical, and back vertical drive for a power adjustable seat. The motors and components which they drive will not be shown or discussed further herein as they are known to those skilled in the art.  
      The first housing end cap  24  also has an upper wall  44  from which a first top snap retention feature  46 , a second top snap retention feature  48  and a third top snap retention feature  50  extend. Each top snap retention feature  46 ,  48 ,  50  includes a securing flange  52  with a barb  54  extending therefrom, and an overstress preventor  56 . The main wall  28  of the first housing end cap  24  includes a first bottom snap retention feature  58 , a second bottom snap retention feature  60 , and a third bottom snap retention feature  62 . Each bottom snap retention feature  58 ,  60 ,  62  includes a securing flange  64  with a barb  66  extending therefrom. Although not shown in this embodiment, the bottom snap retention features  58 ,  60 ,  62  may also include an overstress preventor.  
      The second housing end cap  26  includes a main wall  29  having a first support rod mounting flange  31  and a second support rod mounting flange  33 . The first and second support rod mounting flanges  31 ,  33  are located to receive the conventional support rods (not shown). Extending from the main wall  29  are a first motor housing mounting wall  35 , a second motor housing mounting wall  37 , and a third motor housing mounting wall  39 . Each motor housing mounting wall  35 ,  37 ,  39  includes an alignment tab  41 . Also extending from the main wall  29 , coaxially located within each motor housing mounting wall  35 ,  37 ,  39 , are motor mounting flanges  43 . The motor mounting flanges  43  each receive an end of one of the three motors (not shown).  
      The second housing end cap  26  also has an upper wall  45  from which a first top snap retention feature  47 , a second top snap retention feature  49  and a third top snap retention feature  51  extend. Each top snap retention feature  47 ,  49 ,  51  includes a securing flange  53  with a barb  55  extending therefrom, and an overstress preventor  57 . The main wall  29  of the second housing end cap  26  includes a first bottom snap retention feature  59 , a second bottom snap retention feature  61 , and a third bottom snap retention feature  63 . Each bottom snap retention feature  59 ,  61 ,  63  includes a securing flange  65  with a barb  67  extending therefrom, and an overstress preventor  69 .  
      The seat motors assembly  22  may also include a printed circuit board assembly  71  that includes a printed circuit board (PCB)  72 , which mounts directly to the first housing end cap  24  with fasteners or by some other means. The PCB  72  may include cut out portions  73  for fitting around motor housing mounting walls  36 ,  38 . The printed circuit board assembly  71  has a first electrical connector  74  and a second electrical connector  75 , connected to the PCB  72 , for receiving power/signals. The PCB  72  may include, for example, motor control electronics that distribute the power/signals to the motors.  
      A PCB cover  76  includes cover mounting flanges  77  that snap-fit over corresponding PCB cover mounting tabs  78  on the first housing end cap  24 . The PCB cover  76  mounts to the first housing end cap  24  over the PCB  72  in order to protect the PCB  72  from damage while still allowing access to the first and second electrical connectors  74 ,  75 . The PCB cover  76  easily snaps on and off in order to protect the PCB  72  while still allowing for easy access when needed for servicing.  
      The seat motors assembly  22  also includes a first motor housing  82 , a second motor housing  83 , and a third motor housing  84 . The motor housings  82 ,  83 ,  84  are metal and have a thickness needed to provide sufficient electromagnetic interference protection. Each motor housing  82 ,  83 ,  84  is sized and shaped to hold and support the desired size of bi-directional motor (not shown), which can be a conventional motor.  
      Each of the motor housings  82 ,  83 ,  84  has a first end  85  that mounts about a respective one of the first, second and third motor housing mounting walls  34 ,  36 ,  38 . Each of the motor housings  82 ,  83 ,  84  also has a second opposed end  86  that mounts about a respective one of the first, second and third motor housing mounting walls  35 ,  37 ,  39 . The motor housing mounting walls help to support and assure proper location and orientation of the motor housings  82 ,  83 ,  84 .  
      An alignment recess  87  on each of the first ends  85  of the motor housings  82 ,  83 ,  84  aligns with its respective alignment tab  40  on the first housing end cap  24 . Each of the first ends  85  also includes a top snap-in tab  88  and a bottom snap-in tab (not shown, but similar to the top tab). Each of the second ends  86  includes a top snap-in tab  90  and a bottom snap-in tab  91 . Each of the snap-in tabs  88 ,  90 ,  91  includes a lip  92 . The lips  92  interact with the snap retention features in order to secure the motor housings  82 ,  83 ,  84  to the housing end caps  24 ,  26 , while still allowing for relatively simple and easy disassembly of the seat motors assembly  22  when required for servicing, as discussed below.  
      During assembly of the seat motors assembly  22 , the PCB  72  is secured to the first housing end cap  24  by fasteners or other means, and the PCB cover  76  is mounted over that and secured by engaging the cover mounting flanges  77  over the cover mounting tabs  78 . The motors (not shown) are inserted into the motor housings  82 ,  83 ,  84 , and the motor housings  82 ,  83 ,  84  assembled to the housing end caps  24 ,  26 .  
      The motor housings  82 ,  83 ,  84  are assembled to the housing end caps  24 ,  26  by aligning each alignment recess  87  with its respective alignment tab  40 ,  41  and each snap-in tab  88 ,  90 ,  91  with its respective snap retention feature  46 - 51 . As the end caps  24 ,  26  and motor housings  82 ,  83 ,  84  come together, each of the first ends  85  of the motor housings  82 ,  83 ,  84  will slide over its corresponding motor housing wall  34 ,  36 ,  38 , and each of the second ends  86  will slide over its corresponding housing wall  35 ,  37 ,  39 . In addition, while these components are coming together, the lips  92  on the snap-in tabs  88 ,  90 ,  91  will cause the corresponding securing flanges  52 ,  53 ,  64 ,  65  to elastically flex until the lips  92  slide past the barbs  54 ,  55 ,  66 ,  67 , at which point the snap-in tabs  88 ,  90 ,  91  will snap back close to their original positions. The elastic flexing of the securing flange  52  is shown in  FIG. 5  in phantom and identified as  52 , while the flange  52  after assembly is also shown in  FIG. 5 .  
      The term “snap” as used herein is directed to members that elastically flex while two components are being assembled, and when the components are essentially fully assembled, the members will return (i.e., snap) back close to their original positions in order to secure the components together. This is different than members that are plastically deformed (i.e., permanently take a new shape) during assembly, such as, for example, metal flanges on a first component that are bent down over a second component to secure the two together.  
      The overstress preventors  56 ,  57 ,  69  are each located adjacent to a securing flange  52 ,  53 ,  64 ,  65  in the direction of flexing. They are spaced from the flanges  52 ,  53 ,  64 ,  65  a sufficient distance to allow the flanges to flex as needed during assembly but close enough to prevent the flanges from flexing too far should the components be misaligned during the assembly operation. That is, they help to prevent the securing flanges  52 ,  53 ,  64 ,  65  from being flexed beyond the plastic range and permanently deformed since a permanently deformed securing flange might not snap back to secure the components together.  
      Disassembly for servicing is relatively easy. The securing flanges  52 ,  53 ,  64 ,  65  are flexed until each barb  54 ,  55 ,  66 ,  67  clears its respective lip  92 , and the housing end caps  24 ,  26  are slid away from the motor housings  82 ,  83 ,  84 . The servicing can be performed, and then the components can be reassembled the same as when they were originally assembled. If access to the PCB  72  only is required, then the PCB cover  76  can be easily removed by disengaging the cover mounting flanges  77  from the cover mounting tabs  78  and sliding the PCB cover  76  out of the assembly.  
       FIGS. 6-8  illustrate a second embodiment of the present invention. Since this embodiment is similar to the first, elements in this embodiment that are the same as elements in the first embodiment will be identified with the same element numbers, while elements that have changed and new elements will be identified with 100-series element numbers.  
      In this embodiment, the first housing end cap  124  includes the first motor housing mounting wall  134 , with an alignment tab  40 , and first top and bottom snap retention features  146 ,  158  in order to align and retain the first motor housing  182 . The snap retention features  146 ,  158  vary significantly from the first embodiment. Each snap retention feature  146 ,  158  includes a spaced pair of securing flanges  152 ,  153 , with a pair of overstress preventors  156 ,  157  adjacent to them. The first motor housing  182  has snap-in tabs  188  (only top shown) that include arrowhead shaped lips  192 .  
      Assembly of the seat motors assembly  122  for this embodiment is similar to the first, but with the snap feature differing somewhat. The snap feature as it applies to the top of the first motor housing  182  will be described. During assembly, as the first housing end cap  124  and first motor housing  182  are brought together, the lip  192  (i.e., the arrowhead shaped feature) of the snap-in tab  188  on the first end  185  of the first motor housing  182  presses into the securing flanges  152 . As the snap-in tab  188  press in, it will causes the securing flanges  152  to flex outward elastically. The overstress preventors  156  will assure that the securing flanges  152  are not flexed too far should some misalignment occur during assembly. Again, the first end  185  will seat around the first motor housing mounting wall  134  as the snap-in tab  188  passes through the securing flanges  152 . The securing flanges  152  will then snap back to essentially their unflexed positions, trapping the lips  192  of the snap-in tabs  188 .  
      While changes to the first top and bottom snap retention features  146 ,  158  and top snap-in tab  188  are only shown for the first housing end cap  124  and first end  185  of the first motor housing  182 , these changes are applicable to the other motor housings and the second housing end cap as well.  
       FIGS. 9-11  illustrate a third embodiment of the present invention. Since this embodiment is similar to the first, elements in this embodiment that are the same as elements in the first embodiment will be identified with the same element numbers, while elements that have changed and new elements will be identified with 200-series element numbers. In this embodiment, there is a reduced number of assembly steps since all three motors (not shown) are mounted in a single motor housing.  
      In this embodiment, the seat motors assembly  222  still includes a first housing end cap  224  and a second housing end cap  226  that sandwich a motor housing  293 , but with the motor housing  293  being a single unit formed from an upper motor housing  294  and a lower motor housing  295 . The single housing  293  has a first motor housing portion  282 , a second motor housing portion  283 , and a third motor housing portion  284 . The single, integral motor housing  293  for all three motors may provide more support and overall stiffness to the assembly than embodiments with a separate motor housing for each motor.  
      The first housing end cap  224  includes motor housing mounting walls  234 ,  236 ,  238  for receiving and supporting the first end  285  of the motor housing  293 . The PCB  272  mounts to the first housing end cap  224  with cutout portions  273  for fitting around the motor housing mounting walls  234 ,  236 ,  238 . A PCB cover  276  encloses the PCB  272  and includes cover mounting flanges  277  that mate with cover slots  278  in the motor housing  293 . The first housing end cap  224  also includes alignment tabs  240  that engage corresponding alignment recesses  287  in the motor housing  293 . The first housing end cap  224  has a snap retention feature  246 , which includes a securing flange  252  having a barb  254  on its end. The barb  254  engages with a snap-in slot  288  in the motor housing  293  to retain the motor housing  293  against the first housing end cap  224 . Two snap retention features  248 ,  250  are formed in the main wall  228  of the first housing end cap  224  and are positioned for engagement with snap-in tabs on the second housing end cap  226 , discussed below.  
      The second housing end cap  226  includes motor housing mounting walls (not shown in this embodiment) that receive and support the second end  286  of the motor housing  293 . First and second snap-in tabs  296 ,  297  extend from the second housing end cap  226 . The snap-in tabs  296 ,  297  each include a lip  292 , which engages with a respective one of the snap retention features  248 ,  250  of the first housing end cap  226 , and an extension arm  298 , which extends across the width of the assembly to hold is the assembly together. Of course, the snap retention features and snap-in tabs can be switched between the first and second housing end caps, if so desired.  
      The seat motors assembly  222  may also include a support bracket  299  mounted under assembly that provides additional mounting support for this assembly.  
      The assembly of the components for the seat motors assembly  222  of the third embodiment is similar to the first two, with elastic deformation of snap-type features during the assembly process that engage to secure the assembly together. And, of course, the snap retention features and snap-in tabs of the first two embodiments may be employed with this third embodiment in addition to or in place of the retention features shown in the third embodiment, and vice versa.  
      While certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.