Abstract:
A pulse width modulated solenoid system having low noise characteristics is described. Noise reduction is primarily achieved by separating the solenoid device from the insulator and the manifold housing through the use of rubber isolators and multiple sets of o-rings, thus preventing metal to metal contact. Additional noise reduction is achieved by encapsulating all of the solenoids, using the insulator, the cover plate, the housing, and the screen carrier. Noise levels are also further reduced by minimizing the impact force of the armature against the sleeve by allowing fluid to vent into the upper area of the sleeve, thus causing a dampening effect.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present invention claims priority to U.S. Provisional Patent Application Ser. No. 60/525,358, filed Nov. 26, 2003, the entire specification of which is expressly incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to solenoids and more particularly to pulse width modulated solenoid systems having low noise characteristics. 
     BACKGROUND OF THE INVENTION 
     Solenoids have been used to provide a number of functions in automotive applications including, but not limited to use in automatic transmission systems and the like. For example, the control system of an automatic transmission is typically hydraulically operated through the use of valves which direct and regulate the supply of pressure. This hydraulic pressure control causes either actuation or de-actuation of frictional members for affecting gear changes in the transmission. 
     More recently, automatic transmission designs have included adaptive control systems which utilize electrically operated solenoid-actuated valves for controlling various fluid pressures. However, current solenoid-actuated valve designs have their shortcomings. For example, vibrationally-transmitted impact noise during shifting results in a chattering effect from solenoid actuation. This chattering can be a result of the pulse width modulated (PWM) electronic drive signal which actuates the solenoids. This can occur under step shifting conditions in which the solenoid ramps from 0 to 100 percent duty cycle or vice versa. The vibrational energy generated is at the excitation PWM frequency, as well as the higher order multiple of the drive frequency. This vibrational energy directly transmits from the solenoid through its mounting interface into the transmission housing. The presence of excessive noise and vibration levels is typically undesirable and potentially leads to customer dissatisfaction. 
     One approach to overcoming this problem is found in commonly-assigned U.S. Pat. No. 5,651,391, the entire disclosure of which is expressly incorporated herein by reference, which discloses a solenoid-actuated valve assembly with reduced noise characteristics. More specifically, a rubber retainer and steel retainer secure the valve within a manifold, wherein the rubber retainer absorbs longitudinal vibrations. A plurality of rubber gaskets surround the body of the valve and prevent metal-to-metal contact between the valve body and the manifold for cushioning lateral vibrations of the valve. However, this approach uses a unitary rubber retainer that extends along most of the length of the solenoid assembly, with corresponding raised portions for shrouding the top portions of the respective individual solenoids. This approach is wasteful in that excessive material must be used to manufacture the rubber retainer, as well as being fairly inadaptable, in that it cannot be easily modified should the solenoid assembly layout design be changed later. 
     Therefore, there exists a need for new and improved pulse width modulated solenoid systems having low noise characteristics. 
     SUMMARY OF THE INVENTION 
     In accordance with the general teachings of the present invention, new and improved pulse width modulated solenoid systems having low noise characteristics are provided. 
     More specifically, the present invention preferably provides a solenoid-actuated valve system (e.g., a three-way system) that is vibrationally isolated from the manifold by an isolator member and at least one gasket member (e.g., an o-ring), that are preferably comprised of a resiliently deformable material, such as but not limited to rubber. The present invention further preferably provides a sleeve member (e.g., comprised of a non-magnetic material) disposed within the solenoid and substantially surrounding the armature so as to form a dampening portion therebetween, wherein a fluid (e.g., transmission fluid) is operable to be vented to the dampening portion. Additionally, the armature member is preferably provided with at least one axial groove extending along the external surface thereof. Furthermore, a plunger member is preferably provided at least one axial scalloped flute portion extending along the external surface thereof. 
     Still more specifically, the present invention preferably provides a solenoid-actuated valve system with reduced noise characteristics. The system preferably includes a manifold member having at least one, and more preferably a plurality of bores, formed therein with a longitudinally extending solenoid-actuated valve member disposed within the bore. An insulator member is preferably disposed adjacent to a surface of the bore, and an isolator member (e.g., a round rubber member) is disposed between the insulator member and the valve member (e.g., in proximity to the solenoid portion thereof for cushioning vibrations (e.g., longitudinal vibrations) of the valve member for noise reduction. At least one, and more preferably a plurality, of gaskets (e.g., rubber o-rings) are preferably disposed about the valve member (e.g., in proximity to the valve portion thereof and cushion the valve member with respect to various surfaces (e.g., internal surfaces) of the bore, for cushioning vibrations (e.g., lateral vibrations) of the valve member for noise reduction purposes. 
     In accordance with a first embodiment of the present invention, a solenoid-actuated valve assembly with reduced noise characteristics is provided, comprising: (1) a manifold housing member having first and second bores formed therein; (2) a first solenoid-actuated valve member disposed within said first bore, said first solenoid-actuated valve member including a solenoid portion and a valve portion; (3) a second solenoid-actuated valve member disposed within said second bore, said second solenoid-actuated valve member including a solenoid portion and a valve portion; (4) an insulator member in proximity to said solenoid portions of said first and second solenoid-actuated valve members; (5) a first unitary isolator member disposed between said insulator member and said solenoid portion of said first solenoid-actuated valve member, said first isolator member operable to reduce vibration transmission from said solenoid portion of said first solenoid-actuated valve member to said insulator member; (6) a second unitary isolator member disposed between said insulator member and said solenoid portion of said second solenoid-actuated valve member, said second isolator member operable to reduce vibration transmission from said solenoid portion of said second solenoid-actuated valve member to said insulator member; (7) a first plurality of gasket members disposed about said valve portion of said first solenoid-actuated valve member, said first plurality of gasket members operable to reduce vibration transmission from said valve portion of said first solenoid-actuated valve member to said manifold housing member; and (8) a second plurality of gasket members disposed about said valve portion of said second solenoid-actuated valve member, said second plurality of gasket members operable to reduce vibration transmission from said valve portion of said second solenoid-actuated valve member to said manifold housing member. 
     In accordance with a second embodiment of the present invention, a solenoid-actuated valve assembly with reduced noise characteristics is provided, comprising: (1) a manifold housing member having a first and second longitudinally extending bores formed therein; (2) a first solenoid-actuated valve member disposed within said first bore, said first solenoid-actuated valve member including a solenoid portion and a valve portion; (3) a second solenoid-actuated valve member disposed within said second bore, said second solenoid-actuated valve member including a solenoid portion and a valve portion; (4) an insulator member in proximity to said solenoid portions of said first and second solenoid-actuated valve members; (5) a first unitary resiliently deformable isolator member disposed between said insulator member and said solenoid portion of said first solenoid-actuated valve member, said first isolator member operable to reduce vibration transmission from said solenoid portion of said first solenoid-actuated valve member to said insulator member; (6) a second unitary resiliently deformable isolator member disposed between said insulator member and said solenoid portion of said second solenoid-actuated valve member, said second isolator member operable to reduce vibration transmission from said solenoid portion of said second solenoid-actuated valve member to said insulator member; (7) a first plurality of resiliently deformable gasket members disposed about said valve portion of said first solenoid-actuated valve member, said first plurality of gasket members operable to reduce vibration transmission from said valve portion of said first solenoid-actuated valve member to said manifold housing member; and (8) a second plurality of resiliently deformable gasket members disposed about said valve portion of said second solenoid-actuated valve member, said second plurality of gasket members operable to reduce vibration transmission from said valve portion of said second solenoid-actuated valve member to said manifold housing member. 
     In accordance with a third embodiment of the present invention, a solenoid-actuated valve assembly with reduced noise characteristics is provided, comprising: (1) a manifold housing member having at least two bores formed therein; (2) at least two solenoid-actuated valve members disposed within said bores, said solenoid-actuated valve members including a solenoid portion and a valve portion; (3) an insulator member in proximity to said solenoid portions of said solenoid-actuated valve members; (4) at least two unitary isolator members, each of which are disposed between said insulator member and each of said solenoid portions, said isolator members operable to reduce vibration transmission from said solenoid portions to said insulator member; and (5) at least two gasket members, each of which are disposed about said valve portions, said gasket members operable to reduce vibration transmission from said valve portions to said manifold housing member. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  illustrates a perspective view of a solenoid-actuated valve system, in accordance with the general teachings of the present invention; 
         FIG. 2  illustrates a partial sectional view taken along line  2 - 2  of the solenoid-actuated valve system depicted in  FIG. 1 , in accordance with the general teachings of the present invention; 
         FIG. 3  illustrates a partially broken-away perspective view of a normally applied valve member, in accordance with the general teachings of the present invention; 
         FIG. 4  illustrates a partially broken-away perspective view of a normally vented valve member, in accordance with the general teachings of the present invention; 
         FIG. 5   a  illustrates a partial sectional view of an armature member, in accordance with a first alternative embodiment of the present invention; 
         FIG. 5   b  illustrates a sectional view taken along line  5 - 5  of the armature member depicted in  FIG. 5   a , in accordance with a first alternative embodiment of the present invention; 
         FIG. 6   a  illustrates a partial sectional view of a plunger member, in accordance with a second alternative embodiment of the present invention; 
         FIG. 6   b  illustrates a sectional view taken along line  6 - 6  of the plunger member depicted in  FIG. 6   a , in accordance with a second alternative embodiment of the present invention; and 
         FIG. 7  illustrates a partial sectional view of the solenoid-actuated valve system. 
       The same reference numerals refer to the same parts throughout the various Figures. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     Referring to the Figures generally, and more specifically to  FIGS. 1-4 , there is shown a solenoid-actuated valve system generally at  10 . In accordance with a preferred embodiment of the present invention, the system  10  is preferably a solenoid-actuated three-way valve system, although other types of valve systems are believed to be compatible with the practice of the present invention. In accordance with a highly preferred embodiment of the present invention, the system  10  is intended to be used in conjunction with transmission systems, specifically with respect to the control and/or delivery of transmission fluids therethrough. 
     The system  10  preferably includes a manifold  12  that preferably includes a manifold housing  14  (e.g., a transmission manifold) having at least one, more preferably at least two, and still more preferably a plurality of bores  16  formed therein, the purpose of which will be explained herein. The manifold housing  14  also preferably includes an insulator member  18 , a cover plate member  20 , and one or more fastening members  22  (e.g., screws) operable to secure the cover plate member  20  to the manifold housing  14 . The manifold  12  can preferably include other components, as are generally know in the art, including but not limited to location dowels, clutch return ports, solenoid bowl drain ports, element ports, supply ports, pressure switch ports, and/or the like. 
     In accordance with a preferred embodiment of the present invention, at least one, more preferably at least two, and still more preferably a plurality of valve members are provided. The valve members preferably include a solenoid portion and a valve portion in operable association therewith. In accordance with a preferred embodiment of the present invention, the valve members, and more specifically the valve portions thereof, are at least partially, and still more preferably substantially completely, disposed within the bores  16  of the manifold housing  14 . 
     Referring specifically to  FIGS. 2 and 3 , there is shown a normally applied valve member  100 , including a solenoid portion  102  and a valve portion  104 . The solenoid portion  102  thereof preferably includes a solenoid housing  106  or can enveloping a bobbin coil assembly  108  (including a bobbin member  110  and a coil member  112 ). The bobbin coil assembly  108  preferably envelopes an armature assembly  114  (including a selectively movable armature member  116  and a stem or pin member  118  extending therefrom). In accordance with a preferred embodiment of the present invention, optional crush teats can be incorporated into the top of the bobbin member  110  in order to control positioning of the bobbin member  110 , e.g., during assembly, so as to prevent rotation once partially assembled. A sleeve member  120  preferably envelopes the armature member  116 . The sleeve member  120  and the armature member  116  preferably define a dampening portion  122  within the interior of the sleeve member  120 . A pole piece member  124  is preferably provided in proximity to the valve portion  104  and is preferably spaced and opposed from the dampening portion  122 . An upper flux washer member  126  is preferably provided in proximity to the top surface of the solenoid housing  106 . A terminal member  128  preferably extends from the bobbin member  110 , and is preferably in communication with one or more electrical conduction members  130  (e.g., wires) associated with the insulator member  18 . 
     Still referring to  FIGS. 2 and 3 , the valve portion  104  includes a valve housing  132  enveloping a retainer member  134  disposed therein. The external surface of the valve housing  132  is preferably provided with at least one, more preferably at least two, still more preferably at least three, and most preferably a plurality of annular grooves or shoulder portions  136 , the purpose of which will be explained herein. The retainer member  134  preferably includes an upper seat portion  138  and a lower seat portion  140 . Preferably disposed between the seat portions  138 ,  140 , respectively, is a ball member  142  that is preferably operable to selectively move between the seat portions,  138 ,  140 , respectively, thus allowing or not allowing the flow of transmission fluid through the valve portion  104 . In accordance with a preferred embodiment of the present invention, when the coil member  112  is energized, the armature member  116  will be urged towards the pole piece member  124 , thus causing the stem member  118  to contact the ball member  142 . Conversely, when the coil member  112  is de-energized, the armature member  116  will not be urged towards the pole piece member  124 , thus allowing the ball member  142  to push up the stem member  118  and cause the armature member  116  to return to its default position. In this general manner, the valve portion  104  can be selectively manipulated to control the flow of transmission fluid through the manifold  12 . 
     In order to control the transmission of vibrations and/or noise that occurs when the valve member  100  is actuated, the present invention provides at least one, more preferably at least two, and still more preferably a plurality of isolator members  144  and/or gasket members  146  disposed about various locations of the valve member portion  100 . 
     In accordance with a preferred embodiment of the present invention, an isolator member  144  is disposed about the top external surface of the sleeve member  120 , i.e., disposed between the insulator member  18  and an upper flux washer member  126 . Without being bound to a particular theory of the operation of the present invention, the intended purpose of the isolator member  144  is to cushion vibrations (e.g., longitudinal vibrations) of the valve portion  104  for noise reduction. The isolator member  144  is preferably comprised of a resiliently deformable material, including but not limited to a polymeric material such as rubber. 
     In accordance with a preferred embodiment of the present invention, at least one, more preferably at least two, still more preferably at least three, and most preferably a plurality of gasket members  146  (e.g., o-rings) are disposed about the external surface of the valve housing  132 . Preferably, the gasket members  146  are received in the annular grooves and/or shoulder portions  136  and preferably abut the inner surfaces of the bore  16  (i.e., the manifold housing  14 ). Without being bound to a particular theory of the operation of the present invention, the intended purpose of the gasket members  146  is to cushion vibrations (e.g., lateral vibrations) of the valve portion  104  for noise reduction. The gasket members  146  are preferably comprised of a resiliently deformable material, including but not limited to rubber. 
     Referring specifically to  FIGS. 2 and 4 , there is shown a normally vented valve member  200 , including a solenoid portion  202  and a valve portion  204 . The normally vented valve member  200  is somewhat similar to the normally applied valve member  100 , but does have some significant differences as will be explained herein. However, the solenoid portion  202  is substantially identical in both embodiments. 
     Still referring to  FIGS. 2 and 4 , the valve portion  204  includes a valve housing  206  enveloping a retainer member  208  disposed therein. The external surface of the valve housing  206  is preferably provided with at least one, more preferably at least two, still more preferably at least three, and most preferably a plurality of annular grooves or shoulder portions  210 , the purpose of which will be explained herein. The retainer member  208  preferably includes an upper seat portion  212 , and intermediate seat portion  214 , and a lower seat portion  216 . Preferably disposed between the intermediate seat portion  214  and the lower seat portion  216  is a ball member  218  that is preferably operable to selectively move between the respective seat portions, thus allowing or not allowing the flow of transmission fluid through the valve portion  204 . In accordance with a preferred embodiment of the present invention, overtravel of the ball member  218  in the retainer member  208  was minimized in order to optimize the movement of the ball member  218 , thus helping the ball member  218  seal quickly and consistently during rapid operation. In accordance with a preferred embodiment of the present invention, the height and size of the valve portion  204  can also be reduced by a 2-sided stamped washer seat member  220 , that can be installed either right side up or upside down. 
     A plunger member  222  is preferably provided that is in selective operable association with the stem member  224  (e.g., of the armature member  226 ) and the ball member  218 . The plunger member  222  is preferably operable to engage the upper seat portion  212 . In accordance with a preferred embodiment of the present invention, when the coil member  228  is energized, the armature member  226  will be urged towards the pole piece member  230 , thus causing the stem member  224 , and more specifically the plunger member  222 , to contact the ball member  218 . Conversely, when the coil member  228  is de-energized, the armature member  226  will not be urged towards the pole piece member  230 , thus allowing the ball member  218  to push up the plunger member  222 , and more specifically the stem member  224 , which in turn will return armature member  226  to the default position. In this general manner, the valve portion  204  can be selectively manipulated to control the flow of transmission fluid through the manifold  12 . An additional aspect of the present invention shown in  FIG. 7 , includes an arrangement wherein the valve portions of all the solenoid actuated valve members include a plunger member  222  adjacent the stem member. 
     In order to control the transmission of vibrations and/or noise that occurs when the valve member  200  is actuated, the present invention provides at least one, more preferably at least two, and still more preferably a plurality of isolator members  232  and/or gasket members  234  disposed about various locations of the valve member  200 . 
     In accordance with a preferred embodiment of the present invention, an isolator member  232  is disposed about the top external surface of the sleeve member  236 , i.e., disposed between the insulator member  238  and the upper flux washer member  240 . Without being bound to a particular theory of the operation of the present invention, the intended purpose of the isolator member  232  is to cushion vibrations (e.g., longitudinal vibrations) of the valve portion  204  for noise reduction. The isolator member  232  is preferably comprised of a resiliently deformable material, including but not limited to rubber. Although the isolator member  232  is shown as being a substantially round member having an open middle portion, it should be appreciated that any number of suitable designs can be used in the practice of the present invention. The present design was chosen, in part, due to the desire to at least partially envelope the upper portion of the sleeve member  236  in order to cushion vibrations emanating therefrom and/or therethrough. 
     In accordance with a preferred embodiment of the present invention, at least one, more preferably at least two, still more preferably at least three, and most preferably a plurality of gasket members  234  (e.g., o-rings) are disposed about the external surface of the valve housing  202 . Preferably, the gasket members  234  are received in the annular grooves and/or shoulder portions  212  and preferably abut the inner surfaces of the bore  16  (i.e., the manifold housing  14 ). Without being bound to a particular theory of the operation of the present invention, the intended purpose of the gasket members  234  is to cushion vibrations (e.g., lateral vibrations) of the valve portion  204  for noise reduction. The gasket members  234  are preferably comprised of a resiliently deformable material, including but not limited to rubber. Although the gasket members  234  are shown as being substantially round members having an open middle portion, it should be appreciated that any number of suitable designs can be used in the practice of the present invention. The present design was chosen, in part, due to the desire to at least partially encircle the various portions of the valve portion  204  in order to cushion vibrations emanating therefrom and/or therethrough. 
     As shown, the isolator members  144 ,  232 , respectively, are preferably unitary members, in that, one isolator member  144  is provided for the normally applied valve member  100 , and a completely separate isolator member  232  is provided for the normally vented valve member  200 . In this manner, each valve member, regardless of its design or position in the manifold, can be provided with an individual isolator member, thus obviating the need for large and complex isolator member designs that must be carefully laid out to correspond to multiple valve member locations. 
     Referring specifically to  FIGS. 5   a  and  5   b , there is shown an alternative design of an armature member  300 , in accordance with a first alternative embodiment of the present invention. In order to achieve optimal performance of the armature member  300  traveling through the fluid (e.g., transmission fluid) in its respective sleeve member, at least one, and more preferably at least two, and most preferably a plurality of custom grooves or slots  302  were incorporated into an external surface of the armature member  300 . Without being bound to a particular theory of the operation of the present invention, it is believed that the grooves  302  allow for improved response and performance under cold temperature operational conditions. 
     Referring specifically to  FIGS. 6   a  and  6   b , there is shown an alternative design of a plunger member  400 , in accordance with a second alternative embodiment of the present invention. In order to minimize the size of the solenoid valve, a multi-fluted (e.g., 3 fluted or scalloped surfaces) plunger member  400  with scalloped flutes  402  incorporated into an external surface thereof was provided in order to provide the respective valve portion with a very low profile height, while still maximizing contact area with the bore of the upper seat for guidance and improved life, and also for maximizing the flow area through the flutes  402 . 
     In order to further minimize the height of the valve portions of the present invention, the respective lower gasket members are retained only by the fluid pressure applied from underneath it. A screen carrier member  500  also acts as a back up retention method for the respective lower gasket members. 
     In order to minimize hydraulic force acting on the respective insulator member, the inlet nozzle  600  of the respective valve portions located in the respective retainer members has been minimized. Furthermore, the respective lower gasket members added to the respective retainer members are intended for the purpose of minimizing the applied force. The other two respective gasket members are preferably significantly greater in diameter than the respective lower gasket members in order to minimize the upward force when the valve member is applied, while still allowing for proper insertion of the respective gasket members into the bores. Furthermore, the hydraulic inlet nozzle  600  is preferably placed directly underneath the respective valve portions for minimized height. 
     The present invention was designed to be a high flow, high pressure device with a near linear, repeatable transfer function. This was done, in part, by optimizing the size of the respective seats and all the other orifices, as well as by controlling the overtravel of the armature member in the sleeve member. By way of a non-limiting example, the transfer function of the normally applied valve member was specifically designed to yield higher pressures at a 50% duty cycle level. 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.