Abstract:
An actuator for a vent window of a motor vehicle wherein the drive mechanism interconnecting the output shaft of the motor and the pivot arm controlling the vent window comprises a first worm driven by the motor output shaft, a first worm wheel driven by the first worm, a second worm driven by the first worm wheel, and a second worm wheel driven by the second worm in driving the pivot arm. The first worm wheel is formed of a plastic material and the actuator further includes a coil spring mounted on the housing proximate the second worm wheel and operative to assist the second worm wheel in generating a sealing force sufficient to positively seal the vent window against a window seal of the motor vehicle.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to a power window actuator and particularly to a power window actuator for a swingably or pivotally mounted window such as a rear side vent or corner window of a motor vehicle such as a van.  
         BACKGROUND OF THE INVENTION  
         [0002]    It is desirable to provide a powered rear side vent window for ventilation purposes in vehicles, particularly vans and minivans. These rear side vent windows are generally swingably mounted and open outwardly in the vehicle body and are typically remotely activated as, for example, from the driver&#39;s seat.  
           [0003]    Several types of vehicle power vent window actuators are known and used. Whereas these prior art actuators are generally satisfactory, they typically suffer from one or more disadvantages. Specifically, the prior art actuators are relatively expensive and/or overly large and/or are relatively noisy in operation.  
         SUMMARY OF THE INVENTION  
         [0004]    This invention is directed to an improved vent window actuator.  
           [0005]    More specifically, this invention is directed to a vent window actuator that is inexpensive, quiet in operation, and compact.  
           [0006]    The actuator of the invention is of the type including a housing, an electric motor mounted on the housing, a pivot arm mounted on the housing and adapted to be connected to the vent window to effect opening and closing movement of the vent window in response to pivotal movement of the pivot arm, and a drive mechanism interconnecting the output of the motor and the pivot arm and operative in response to energization of the motor to pivot the pivot arm and move the vent window.  
           [0007]    According to the invention, the drive mechanism comprises a first worm driven by the motor, a first worm wheel driven by the first worm, a second worm driven by the first worm wheel, and a second worm wheel driven by the second worm and driving the pivot arm. This arrangement, employing two successive worm drives, provides the quiet operation inherent in a worm drive and, by virtue of the speed reduction achieved utilizing the successive worm drives, allows the use of a smaller, less expensive motor.  
           [0008]    According to a further feature of the invention, the first worm wheel is formed of a plastic material. This choice of material, which is made possible by the fact that the back drive loading imposed on the actuator is largely absorbed by the second worm drive, allows the cost of the actuator to be further reduced by virtue of the relatively inexpensive plastic material of the first worm wheel.  
           [0009]    According to a further feature of the invention, the actuator further includes a coil spring mounted on the housing proximate the second worm wheel and operative to assist the second worm wheel in generating a sealing force sufficient to positively seal the vent window against the window seal of the motor vehicle. This arrangement allows the actuator to satisfy even very high window sealing requirements irrespective of the use of a relatively small, low power motor.  
           [0010]    According to a further feature of the invention, the drive mechanism comprises a first shaft extending coaxial with the motor output and driven by the motor, a second shaft driven by the first shaft and extending perpendicular to the first shaft, and a third shaft extending perpendicular to the first and second shaft, driven by the second shaft, and driving the pivot arm. These three drive shafts arranged in a mutually perpendicular or cross relationship facilitate the compact packaging of the drive mechanism of the actuator and ensure a robust and smooth transmission of power from the motor to the pivot arm.  
           [0011]    According to a further feature of the invention, the motor includes a hub at one end thereof and an output shaft at another end thereof; the first worm is mounted on the output shaft; the housing includes a cavity, a first saddle proximate one end of the cavity, and a second saddle proximate another end of the cavity; and the motor is mounted in the cavity with a free end of the output shaft journaled in the first saddle and the motor hub seated in the second saddle. This arrangement allows a firm, positive mounting of the motor in the housing whereby to eliminate motor wobble and consequent excessive wear in the drive mechanism.  
           [0012]    Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:  
         [0014]    [0014]FIG. 1 is a fragmentary perspective view of a motor vehicle employing a vent window actuator according to the invention;  
         [0015]    [0015]FIG. 2 is a perspective view of the actuator with a housing cover member removed;  
         [0016]    [0016]FIG. 3 is a perspective view of the main body member of the actuator housing also showing, in exploded fashion, the actuator motor and the housing cover;  
         [0017]    [0017]FIG. 4 is a detailed sectional view showing the mounting of the motor in the housing;  
         [0018]    [0018]FIG. 5 is a side elevational view of an output worm assembly utilized in the actuator;  
         [0019]    [0019]FIG. 6 is an end view of the output worm assembly;  
         [0020]    [0020]FIG. 7 is a perspective view of an output shaft assembly utilized in the actuator;  
         [0021]    [0021]FIG. 8 is a side elevational view of the output shaft assembly;  
         [0022]    [0022]FIG. 9 is a perspective view of bearing utilized in the actuator;  
         [0023]    [0023]FIG. 10 is a detailed view of the actuator motor;  
         [0024]    [0024]FIG. 11 is a view of an actuator arm assembly employed in the actuator;  
         [0025]    [0025]FIGS. 12 and 13 are perspective views of terminals utilized in the actuator;  
         [0026]    [0026]FIGS. 14 and 15 are detail views showing the mounting of the motor in the actuator housing; and  
         [0027]    [0027]FIG. 16 is a detail end view of the actuator housing. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0028]    The actuator  10  of the invention is seen in FIG. 1 in association with a motor vehicle  12  which is shown fragmentarily. The motor vehicle  12  may be of a minivan type and includes a D pillar  14 , a vent window  16  pivotally mounted in a vent window opening  18  for movement by the actuator  10  between open and closed positions.  
         [0029]    Actuator  10  (FIGS. 2 and 3) includes a housing  20 , a motor  22 , a motor worm  24 , an output worm assembly  26 , an output shaft assembly  28 , a spring  30 , a link  32 , and a link or handle  34 .  
         [0030]    Housing  20  is suitably formed in a molding operation of a plastic material such, for example, as a glass-filled polyester. Housing  20  includes a main body housing member  36  and a planar cover or lid  38 . Main body housing  36  is suitably configured to accommodate the drive mechanism of the actuator, and cover  38  has a planar configuration and is adapted to be seated within a rim  36   a  of the main body housing to encapsulate the drive mechanism within the housing. The cover may be secured to the main body housing utilizing suitable fasteners coacting with holes  38   a  in the cover and holes  36   b  in the main body housing. Housing  20  is secured to D pillar  14  (FIG. 1) utilizing suitable fasteners passing through apertures  36   t  in main body housing  36 .  
         [0031]    Motor  22  is sized to fit in a recess or cavity  36   c  defined by main body housing  36  and comprises a fractional horse power  6000  rpm direct current motor of the type typically used to control automotive door lock circuits. The motor, for example, may comprise a motor available from Johnson Electric Industrial Manufacturing Ltd. of Hong Kong, China as part number NF243G/NS/2502814E0. Motor  22  includes a main body housing  42 , an output shaft  44 , a connector  46 , and a flux jacket  48 . Flux jacket  48  is positioned in surrounding relation to housing  42  and connector  46 , which may be formed of a suitable plastic material, is received in an open end of the housing  42  and includes a hub portion  46   a  journaling the rear end of output shaft  44 .  
         [0032]    Motor  22  (see also FIGS. 4, 14 and  15 ) is positioned in cavity  36   c  with hub  46   a  seated in a U-shaped saddle  36   d  defined proximate one end of cavity  36   c  and with the free end  44   a  of output shaft  44  journaled in a U-shaped saddle  36   e  defined at the blind end of a groove  36   f  opening in the end of cavity  36   c  opposite saddle  36   d . Motor worm  24  may be formed of a suitable brass material and is press fit onto motor output shaft  44  to expose the free end  44   a  of the output shaft for journaling in saddle  36   e . Worm  24  may, for example, have a diametral pitch of 48 teeth per inch and a lead angle of 12° right hand.  
         [0033]    Output worm assembly  26  (FIGS. 2, 5, and  6 ) includes a shaft  48 , an output worm  48   a  formed integrally with the shaft, and a worm wheel  50 . Worm wheel  50  is formed of a suitable plastic material, such as nylon, and is press fit on a hub portion  48   b  of shaft  48  utilizing suitable knurling on the hub portion. Worm wheel  50  has helical teeth with a helix angle of 12° right hand and a diametral pitch of 48 teeth per inch.  
         [0034]    Shaft  48  and worm  48   a  are formed of a suitable ferrous material, such, for example, has SAE steel 12 L14. Output worm  48   a  has a lead angle of six° right hand and a diametral pitch of 48 teeth per inch.  
         [0035]    Output worm assembly  26  is positioned in housing main body  36  utilizing spherical bearings  52  (FIG. 9) received with a press fit in spherical sockets  36   g  (FIG. 3) opening at laterally-spaced locations in the upper face  36   f  of housing  36 . A first spherical bearing  52  receives one free end  48   c  of shaft  48  and a second spherical bearing  52  receives the other free end  48   d  of the shaft to mount the shaft axis at right angles with respect to the axis of the output shaft of the motor with worm wheel  50  positioned in the groove  36   f  in meshing engagement with motor worm  24  and with suitable saddle cutouts  36   h  in the housing accommodating the various intermediate segments of the shaft  48 .  
         [0036]    Output shaft assembly  28  (FIGS. 2, 7, and  8 ) comprises an output shaft  54  and an output gear  56  both formed of a suitable ferrous material. Gear  56  is press fit on one end of shaft  54  to expose a pilot or journal portion  54   a  and includes straight-cut gears having a diametral pitch of 48 teeth per inch.  
         [0037]    Output shaft assembly  28  is positioned in housing member  36  with gear  56  positioned in a circular cavity  36   i  opening in the upper face  36   f  of the housing and arranged in meshing engagement with output worm  48   a  with the portion of shaft  54  remote from pilot end  54   a  extending downwardly in a perpendicular journal bore  36   j  opening in a recessed face  36   k  of the housing. The axis of shaft  54  is thus positioned perpendicular or crossed with respect to the axis of shaft  48  and perpendicular or crossed with respect to the axis of the motor output shaft  44 .  
         [0038]    Spring  30  comprises a coil spring  30  positioned in surrounding relation to a hollow post  361  upstanding from housing face  36   k  in surrounding relation to an aperture  36   t  with one end  30   a  of the spring anchored in an anchor socket  36   m  defined by the housing and the other end  36   b  (FIG. 7) of the spring hooked into hole in output gear  56 . The spring is arranged to assist movement of output gear  56  and output shaft  54  in a direction to close vent window  16 .  
         [0039]    With cover  38  in place over housing member  36 , a finger  38   b  (FIGS. 4 and 14) downstanding from the main planar body  38   c  of the cover engages the upper face  22   a  of motor  22  to press connector hub portion  46   a  downwardly in saddle  36   d  and press motor output shaft  44   a  downwardly in saddle  36   e  and a socket  38   d  defined on the lower face of the cover journals the upper pilot end  44   a  of shaft  54 . Journal  36   d  is coaxial with the axis of bore  36   j  whereby to provide precise perpendicular or cross positioning of the axis of shaft  54  relative to the axis of shaft  48  and relative to the axis of the motor output shaft. The in place cover also serves to trap bearings  52  in sockets  36   j  whereby to firmly position the axis of shaft  48  and further serves to preclude upward displacement of spring  30 . The dimensional parameters are chosen such that (1) the lower face  22   b  of the in place motor is spaced above the floor  36   n  of cavity  36   c  so that the in place motor is supported solely by saddles  36   d  and  36   e  and finger  38   b , and (2) finger  38   b  is compressed between the main body of the cover and the upper face of the motor to pressure seat hub portion  48   a  and output shaft  44   a  in the respective saddles.  
         [0040]    Link  32  (FIGS. 1, 2, and  11 ) includes a main body portion  32   a  and a crank or pivot arm portion  32   b . Main body portion  32   a  is internally splined and is fitted over external splines  54   b  on shaft  54  within bore  36   j  of the housing and extends outwardly from the lower face of the housing to position pivot arm portion  32   b  exteriorly of the housing.  
         [0041]    Handle  34  is suitably pivotally secured to the free end of pivot arm portion  32   b  and includes a ball socket joint  34   a  at its free end for suitable connection to a bracket  60  suitably secured to an inner face of vent window  16 .  
         [0042]    Power is provided to the motor  22  via a pair of terminals  62  and  64 . Each terminal defines a prong or plug portion  62   a / 64   a , a contact portion  62   b / 64   b , and a bridge portion  62   c / 64   c  interconnecting the prong and contact portions.  
         [0043]    When assembling the actuator, terminal prong portions  62   a ,  64   a  are passed through apertures  36   p  (FIGS. 14 and 16) in housing end wall  36   q  proximate saddle  36   d  to position the prong portions  62   a / 64   a  in on edge stacked relation in an external socket housing  36   r  formed integrally with housing member  36  and extending from housing wall  36   q  and position pilot portions  62   d / 64   d  of contacts  62   b / 64   b  in laterally spaced locator holes  36   s  in housing floor  36   n  proximate saddle  36   d . Motor  22  is now installed in cavity  36   c  by positioning connector hub  46   a  in saddle  36   d  and positioning output shaft  44   a  in saddle  36   e  while simultaneously inserting contacts  62   b / 64   b  in laterally spaced female sockets  66  (FIGS. 4 and 14) mounted in the lower face of connector  46 , whereby to power of the actuator simply by inserting an electrical plug into the open end of socket housing  36   r  to access the stacked prongs  62   a / 64   a.    
         [0044]    The ratios of the successive worm drive assembly are chosen such as to provide an overall drive ratio between the output shaft of the motor and the link  32  of 600:1 and the parameters of the vent window are chosen such that the window undergoes a movement of 135° between open and shut positions.  
         [0045]    The vent window actuator of the invention will be seen to provide many important advantages. Specifically, the overall drive ratio provided by the successive worm drives allows the use of a relatively small and relatively inexpensive motor thereby providing cost savings. Further cost savings are provided by the fact that the motor may comprise a volume-produced motor already in volume use to control automotive door lock circuits. The cost of the actuator is further reduced by the use of a plastic worm wheel in engagement with the motor worm. The use of a plastic worm wheel engaging the motor worm is made possible by the fact that the worm drive of the output shaft assembly absorbs much of the back loading in the system so that the loading experienced at the interface of the motor worm and the worm wheel of the output worm assembly is sufficiently reduced to allow the use of a non-ferrous, relatively inexpensive material at this interface. The use of two successive worm drives also provides quieter operation for the actuator as compared to prior art actuators employing metal-to-metal drive throughout and the cross axis gearing defined by the successive worm drives provides a compact package allowing a reduction in the overall size of the actuator. The actuator package size is further reduced by the use of a smaller motor. The cross axis arrangement of the gearing also reduces shaft misalignment problems and provides a smooth, robust drive mechanism. The mounting of the motor in the housing utilizing the saddles engaging the free end of the motor output shaft and the hub portion on the integral connector in combination with the finger of the cover provides firm mounting for the motor whereby to reduce motor wobble and minimize wear in the drive system occasioned by misalignments. The use of a connector formed integrally with the motor and positioned within the housing of the actuator further reduces the complexity and cost of the unit since the connector in known manner incorporates built-in RFI provisions so that there is no need to separately provide radio frequency interference protection for the actuator. The use of the spherical bearings mounting the output shaft assembly provides a further self-aligning feature whereby to further minimize wear in the system due to misalignments in the drive assembly. The use of the separate assist spring coacting with the output shaft assembly allows the use of a relatively small motor even in installations requiring a high sealing force as between the vent window and the adjacent window seal of the motor vehicle. The integration of the connector into the motor and thereby into the housing combined with the terminals extending from the outside of the housing provide a simple and inexpensive electrical connection for the motor, and the rigid enclosed box design of the housing adds strength to the actuator as compared to prior art actuators utilizing a relatively weak open section housing.  
         [0046]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.