Patent Publication Number: US-2019199163-A1

Title: Motor retainer

Description:
TECHNICAL FIELD 
     This disclosure relates to a motor retainer for retaining a motor within a motor housing. 
     BACKGROUND 
     Electric motor systems usually include a motor, a leadframe connected to the motor, and a motor housing configured and sized to receive the motor and the motor leadframe. During assembly, the leadframe is connected to the motor, and then the leadframe-motor assembly is inserted into the motor housing. Several difficulties arise when assembling the motor system. Currently, during assembly, the leadframe-motor assembly is inserted into the housing, more specifically dropped into the housing, which might cause damage to the motor or the leadframe or both. Another difficulty during assembly is correctly positioning the leadframe-motor assembly within the housing. Lastly, it is also difficult to prevent motor rocking or motor vibration during assembly. Therefore, it is desirable to improve the assembly of the electric motor system to better position the leadframe-motor assembly within the motor and reduce motor rocking and vibration. 
     SUMMARY 
     One aspect of the disclosure provides a motor retainer having a base and at least one arm. The base has an inner surface and an outer surface and includes a washer having at least one concave wave adjacent to at least one convex wave. The at least one arm extends away from the inner surface of the base and tapers towards a center of the motor retainer. 
     Implementations of the disclosure may include one or more of the following optional features. In some implementations, the at least one arm extends away from the at least one concave wave. In some examples, the base includes an outer portion having an inner diameter greater than an outer diameter of the washer. 
     The at least one arm may include a proximal end connected to the base and tapering towards the center of the washer, a distal end, and an elbow between the proximal end and the distal end. The distal end tapers away from the center of the motor retainer. 
     In some implementations, an overmold covers a portion of the at least one arm. The overmold may be a plastic overmold or a rubber overmold. 
     In some examples, the base defines a transverse axis and a longitudinal axis. The base extends along a plane defined by the transverse axis and the longitudinal axis. The at least one arm may form an acute angle with the plane. The acute angle may be less than 20 degrees. 
     Another aspect of the disclosure provides a yoke motor retainer that includes a base, a connector, a cylindrical arm, a window, and a protrusion. The base has an inner surface and an outer surface and includes a washer having at least one concave wave adjacent to at least one convex wave. The connector extends away from the inner surface of the base. The cylindrical arm is supported by the connector and extends away from the base. The window is defined by the cylindrical arm and includes window edges. The protrusion extends away from at least one window edge and away from the cylindrical arm. 
     Implementations of this aspect of the disclosure may include one or more of the following optional features. In some implementations, the window includes a first cutout and a second cutout. Additionally, the protrusion may include an elbow extending away from a first window edge to a second window edge being opposite to the first window edge. The elbow may have a concave shape. In some examples, the protrusion includes a finger extending away from a first window edge. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a perspective view of an exemplary motor retainer. 
         FIG. 1B  is an exploded view of a motor housing configured to receive the exemplary motor retainer of  FIG. 1A . 
         FIG. 1C  is a sectional view of a motor housing supporting the exemplary motor retainer of  FIG. 1A . 
         FIG. 1D  is a sectional view of a motor-leadframe assembly partially inserted in the housing supporting the exemplary motor retainer of  FIG. 1A . 
         FIG. 1E  is a sectional view of the motor-leadframe assembly partially inserted in the housing supporting the exemplary motor retainer of  FIG. 1A , where the leadframe is adjusted to fit in the housing. 
         FIG. 1F  is a sectional view of the motor-leadframe assembly, the exemplary motor retainer, and the housing of  FIG. 1E . 
         FIG. 1G  is a sectional view of the motor-leadframe assembly received by the exemplary motor retainer and housed by the motor housing. 
         FIG. 1H  is a sectional view of the motor-leadframe assembly, the exemplary motor retainer, and the motor housing of  FIG. 1G . 
         FIG. 2A  is a perspective view of an exemplary motor retainer. 
         FIG. 2B  is a perspective view of the exemplary motor retainer of  FIG. 2B  having arm covers. 
         FIG. 3  is a schematic view of an exemplary arrangement of operations for inserting a motor into a motor housing having the motor retainer of  FIGS. 1A-2B . 
         FIG. 4A  is a side bottom perspective view of an exemplary yoke motor retainer. 
         FIG. 4B  is a side top perspective view of the exemplary yoke motor retainer of  FIG. 4A . 
         FIG. 4C  is a perspective view of an exemplary yoke motor retainer having support fingers. 
         FIG. 4D  is a perspective view of the exemplary motor retainer of  FIG. 4A  supporting a motor. 
         FIG. 5  is a schematic view of an exemplary arrangement of operations for inserting a motor into a motor housing having the motor retainer of  FIGS. 4A-4D . 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1A-2B , a motor retainer  100 ,  100   a ,  100   b  includes a body  110  having a base  120  and at least one arm  130  extending away from the base  120 . The base  120  defines a transverse axis X and a longitudinal axis Y. In some examples, the base  120  extends along an X-Y plane defined by the transverse axis X and the longitudinal axis Y. The body  110  defines a central vertical axis Z. In some examples, the arms  130  are equally spaced about the central vertical axis Z from a top view. As shown, the body  110  includes three arms that are spaced trilaterally (e.g., 120 degrees apart) about the central vertical axis Z. The body  110  may include any number of arms  130 , for example, the body  110  may include four arms  130  that are spaced quadrilateraly (e.g., 90 degrees apart) about the vertical axis Z. In other examples, the arms  130  are not equally spaced apart. 
     The base  120  includes an outer surface  122  and an inner surface  124  opposite the outer surface  122 . The at least one arm  130  extends away from the inner surface  124  of the base  120 . The base  120  includes a washer  140  defining a center opening  150 . The washer  140  includes at least one concave wave portion  140   a  adjacent to at least one convex wave portion  140   b . As shown, the washer  140  includes three concave wave portions  140   a  and three convex wave portions  140   b . Each concave wave portion  140   a  is positioned between first and second convex wave portions  140   b . Similarly, each convex wave portion  140   b  is positioned between first and second concave wave portion  140   a . In some examples, the washer  140  may include more concave and convex wave portions  140   a ,  140   b . A center of the convex wave portion  140   b  is flush with the X-Y plane, and a center of the concave wave portion  140   a  curves away from the X-Y plane. 
     Referring to  FIGS. 1A-1H , in some implementations, the base  120  includes an outer portion  160  defining an inner diameter Da being greater than an outer diameter Db of the washer  140 . The outer portion  160  surrounds the washer  140 . In some examples, the washer  140  and the outer portion  160  are concentric about center axis Z. As such, the outer portion  160  surrounds the washer  140  and is separated from the washer  140  by a distance. At least one connector area  142  connects the washer  140  and the outer portion  160 . In some examples, the connector area  142  connects to the washer  140  at the convex wave portion  140   b . In some examples, the center of the convex wave portion  140   b  is coplanar with the outer portion  160  of the base  120 . Therefore, the concave wave portion  140   a  extends away from the X-Y plane defined by the outer portion  160 . 
     With continued reference to  FIGS. 1A-2B , the arm  130  extends away from the base  120 . In some examples, the arm  130  forms an acute angle with the base  120 , i.e., the X-Y plane. As shown, the motor retainer  100  includes three arms  130  equally spaced around the periphery of the base  120 . In other words, the arms  130  are tapered towards the center axis Z. In some examples, each arm  130  includes a proximal end  132 , an elbow  134  and a distal end  136 . The proximal end  132  of the arm  130  tapers in towards the center axis Z, the elbow  134  connects the proximal end  132  and the distal end  136  which tapers away from the center axis Z. The arms  130  form a receptacle  170  for receiving a motor  200 , e.g., a brushed DC motor. The shape of the arms  130  allow the motor  200  to be retained by the elbows  134  providing slow and controlled insertion during assembly and prevents the motor  200  from rocking during operation. 
       FIGS. 1B-1H  show a motor retainer  100  retaining the motor  200 , e.g., a brushed DC motor. Referring to  FIG. 1B , the motor  200  is releasably connected to a motor leadframe  210 . A housing  300  includes a lower housing portion  310  configured to support the motor  200  and an upper housing portion  320  defining a receptacle  322  configured to support and receive a motor leadframe  210 . The lower housing portion  310  has a cylindrical wall  312  configured to receive the motor retainer  100  and the motor  200  in a lower housing receptacle  314 . The cylindrical wall  312  is sized to receive the motor  200 . In some examples, the housing  300  is a die cast housing. 
     With additional reference to  FIG. 1C , the motor retainer  100  is inserted into the housing  300 , e.g., the lower housing portion  310 . The outer surface  122  of the base  120  engages with a bottom portion  316  of the housing  300 . 
       FIGS. 1D and 1E  illustrate a partial insertion of the motor  200  into the motor retainer  100  that is positioned within the lower portion  310  of the housing  300 . The arms  130  of the motor retainer  100 , e.g., the elbows  134 , hold the motor  200  preventing it from dropping in the lower portion  310  of the housing and allowing for rotational alignment of the motor leadframe  210  prior to fully inserting the motor  200  into the housing  300 . The arms  130 , e.g., the elbows  134 , allow for a controlled insertion of the motor  200  due their shape that provides a grip about the motor  200  as shown in section A. 
     Referring to  FIGS. 1E and 1F , once the motor leadframe  210  is aligned with the leadframe housing portion  320 , the motor  200  is fully inserted into the lower housing portion  310  causing the leadframe to be inserted into the leadframe housing  320  as shown in  FIGS. 1G and 1H  and the motor  200  inserted into the motor retainer  100 . 
       FIGS. 1G and 1H  show the motor  200  fully inserted within the motor retainer  100 . As shown, at section A, the arms  130 , e.g., the elbows  134 , retain the motor  200  by providing side retention to prevent the motor  200  from rocking. Moreover, the connector areas  142  restrict the lateral movement of the wave washer  140 . Once the motor  200  is received by the motor retainer  100 , the wave washer  140  is compressed as shown in section B providing axial motor load. In addition, the motor retainer  100  is designed to center the motor  200  within the motor receptacle  170 . 
     Referring to  FIG. 2A , in some implementations, the motor retainer  100   b  includes a body  110  having a base  120  and at least one arm  130  as described with respect to  FIGS. 1A-1H . As shown, the body  110  includes a base  120  having a washer  140 . The washer  140  is similar to the washer described with respect to  FIGS. 1A-1H . As shown, the connection area  142  connects the arms  130  and the washer  140 , e.g., the convex portion  140   b  of the washer  140 . 
     Referring to  FIG. 2B , in some implementations, the arms  130  may include an overmold  138 , e.g., plastic or rubber or any other material, as shown in  FIG. 2B . The overmold  138  may cover the arms  130  or a partial portion of the arms  130 . For example (not shown), the overmold  138  may cover the elbow  134  and the distal ends  136  of the arm  130  to provide a better grip of the motor  200  during installation. 
       FIG. 4  provides an example arrangement of operations for a method M 300  of assembling a motor system having a motor retainer  100 , a motor-leadframe assembly including a motor  200  and a motor leadframe  210 , and a motor housing  300  according to  FIGS. 1A-2B . At block M 302 , the method M 300  includes inserting the motor retainer  100  in the receptacle  322  of the lower portion  310  of the housing. At block M 304 , the method M 300  includes partially inserting the motor-leadframe assembly in the receptacle  170  defined by the arms  130  of the motor retainer  100 . At block M 306  the method M 300  includes adjusting the motor-leadframe assembly for alignment with the second portion  320  of the motor housing  300 . At block M 308 , the method M 300  includes controllably inserting the motor-leadframe assembly in the housing  300 . 
     Referring to  FIGS. 4A-4D , in some implementations, a yoke motor retainer  400  includes a body  410  having a washer  140  and a cylindrical arm  420  defining a receptacle  402  for receiving a motor  200 . The washer  140  is connected to the cylindrical arm  420  by way of at least one connector  142 . The washer  140  defines a center opening  150 . The washer  140  includes at least one concave wave portion  140   a  adjacent to at least one convex wave portion  140   b . As shown, the washer  140  includes three concave wave portions  140   a  and three convex wave portions  140   b . Each concave wave portion  140   a  is positioned between first and second convex wave portions  140   b . Similarly, each convex wave portion  140   b  is positioned between first and second concave wave portion  140   a . In some examples, the washer  140  may include more concave and convex wave portions  140   a ,  140   b . A center of the convex wave portion  140   b  is flush with an X-Y plane defined by a transverse axis X and a longitudinal axis Y. The cylindrical arm  420  extends away from the X-Y plane along a central vertical axis Z. The cylindrical arm  420  may define a trough  422  extending along a height of the cylindrical arm  420 . In some examples, the cylindrical arm  420  defined more than one trough  422  extending along the height of the cylindrical arm  420 . In this case, the yoke motor retainer  400  includes additional connectors  142  connecting each portion of the cylindrical arm  420  with the washer  140 . 
     In some implementations, the cylindrical arm  420  is used as a motor flux yoke. A motor yoke is the body of a motor, e.g., AC motor or DC motor. The motor yoke supports the motor poles, provides an outer most cover for the motor, and forms a magnetic circuit. Therefore, the cylindrical arm  420  provides extra motor shield cover to eliminate electromagnetic interference (EMI). 
     As shown, the cylindrical arm  420  of the motor retainer  400  defines one or more windows  430  having window edges  431 , where each window  430  has at least two cutouts  432  separated by a mullion or elbow  434 . As shown, the window  430  includes a first cutout  432   a  separated from a second cutout  432   b  by a mullion or elbow  434  extending between the first and second cutouts  432   a ,  432   b . The mullion or elbow  434  has a concave shape with respect to the cylindrical arm  420  and extends away from the cylindrical arm  420 . Similar to the elbow  134  described with respect to  FIGS. 1A-2B , the elbow  434  allows the yoke motor retainer  400  to be controllably inserted within a housing of the motor (not shown). 
     Referring to  FIG. 4B , in some implementations, the yoke motor retainer  400  includes integrated mounting tabs  440 , each defining a hole  442 . The hole  442  is sized to receive a bolt or a screw for mounting the yoke motor retainer  400 . 
     Referring to  FIG. 4C , in some implementations, the cylindrical arm  420  of the motor retainer  400  further defines another window  450  that includes a finger  452  extending within the window  450  and extending away from the cylindrical arm  420 . The finger  452  provides additional grip and controlled movement during assembly of the yoke motor retainer  400  (while supporting the motor  200 ) within the lower portion  310  of the housing  300 . 
     In some implementations, the base  120  of the yoke motor retainer  400  may include an outer portion  160  as described in  FIGS. 1A-1H . Additionally or alternatively, the elbows  434  and/or the fingers  452  may be overmolded to provide added grip between the yoke motor retainer  400  and the housing  300 . 
     Referring to  FIG. 4D , during assembly, the motor  200  is inserted into the yoke motor assembly  400 . The cylindrical arm  420  provides a tight grip around the motor  200  and the center  150  received a motor shaft  202 . The motor-retainer assembly  460  shown in  FIG. 3D  is then controllably released in the lower portion  310  of the housing  300 . 
       FIG. 5  provides an example arrangement of operations for a method M 500  of assembling a motor system having a yoke motor retainer  400 , a motor-leadframe assembly including a motor  200  and a motor leadframe (not shown), and a motor housing  300  according to  FIGS. 4A-4D . At block M 502 , the method M 500  includes receiving the motor-leadframe assembly in the receptacle  402  of the yoke motor retainer  400 . At block M 504 , the method M 500  includes partially inserting the yoke motor retainer  400  in the receptacle  322  of the lower portion  310  of the housing (not shown). At block M 506 , the method M 500  includes adjusting the yoke motor retainer  400  to align the motor leadframe with the second portion of the motor housing configured to receive the motor leadframe. At block M 508 , the method M 300  includes controllably inserting the yoke motor retainer (including the motor  200  and motor leadframe) in the housing (not shown). 
     A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims. For example, the actions recited in the claims can be performed in a different order and still achieve desirable results.