Housing including snag-fit connection between housing components

A vehicle seat actuator includes an electric motor and a gear set that connects the drive motor to the seat and transmits the output of the motor to the vehicle seat. The drive motor and gear set are each disposed in an individual, dedicated housing component. The individual housing components are then assembled together to provide the actuator. The housing components are maintained in the assembled configuration using snap fit mechanical fasteners. Each snap-fit fastener includes a receiving portion provided on one housing component and a retaining portion provided on the other housing component. The receiving portion may be a through hole formed in the drive motor housing, while the retaining component protrudes from an outer surface of the gear housing and forms a snap-fit engagement with the receiving portion.

BACKGROUND

Actuators such as those used to adjust seat position within a vehicle may include an electric motor and a gear set. The gear set connects the drive motor to the vehicle seat, and transmits the output of the motor to the vehicle seat. The drive motor and gear set may be fabricated separately and disposed in individual housing components. The individual housing components are then assembled together to provide the actuator. The housing components are maintained in the assembled configuration using mechanical fasteners such as screws. However, using screws to secure housing elements together may increase the number of parts that form the assembly and increase manufacturing steps and complexity. Increased number of parts and manufacturing complexity results in an increased actuator cost.

A need exists for an actuator housing that has fasteners that securely join the housing components, while reducing the number of parts that form the actuator assembly and reducing manufacturing complexity.

SUMMARY

In some aspects, an actuator housing includes a gear housing and a drive motor housing that is secured to the gear housing via a fastener. One of the drive motor housing and the gear housing includes a sidewall and a flange. The flange protrudes from the sidewall in a direction that is perpendicular to the sidewall, and includes a through hole that extends between a flange first side and a flange second side. The fastener includes a receiving portion that includes the through hole; and a retaining portion that protrudes from an outer surface of the other of the drive motor housing and the gear housing. The retaining portion forms a snap-fit engagement with the receiving portion, the retaining portion comprising a post and a beam. The post includes a post first end that is fixed to the outer surface, and a post second end that is opposed to the post first end in which a longitudinal axis of the post extends through the post first end and the post second end. The beam includes a beam fixed end that extends from the post second end; and a beam free end that is spaced apart from the beam fixed end. The beam is cantilevered from the post second end so as to overlie the post and extend at an acute angle relative to the longitudinal axis. The beam free end is spaced apart from the longitudinal axis by a distance that is greater than a radius of the through hole. In addition, the post is configured to extend through the through hole such that the outer surface of the gear housing abuts the flange first side, the post protrudes outward relative to the flange second side, and the beam free end faces the flange second side.

In some aspects, a fastener is configured to join a first housing portion to a second housing portion. The first housing portion includes a sidewall; and a flange that protrudes from the sidewall in a direction that is perpendicular to the sidewall. The flange includes a through hole that extends between a flange first side and a flange second side. The fastener includes a receiving portion that includes the through hole; and a retaining portion that protrudes from an outer surface of the second housing portion and forms a snap-fit engagement with the receiving portion. The retaining portion includes a post and a beam. The post includes a post first end that is fixed to the outer surface of the second housing portion and a post second end that is opposed to the post first end in which a longitudinal axis of the post extends through the post first end and the post second end. The beam includes a beam fixed end that extends from the post second end; and a beam free end that is spaced apart from the beam fixed end. The beam is cantilevered from the post second end so as to overlie the post and extend at an acute angle relative to the longitudinal axis. The beam free end is spaced apart from the longitudinal axis a distance that is greater than a radius of the through hole. In addition, the post is configured to extend through the through hole such that the outer surface of the second housing portion abuts the flange first side, the post protrudes outward relative to the flange second side, and the beam free end faces the flange second side.

In some embodiments, the first end of the post has a first dimension along a first transverse axis that is perpendicular to the longitudinal axis, and the second end of the post has a second dimension along the first transverse axis, and the second dimension is less than the first dimension.

In some embodiments, the first end of the post has a third dimension along a second transverse axis that is perpendicular to the longitudinal axis and to the first transverse axis, and the third dimension is less than the first dimension.

In some embodiments, the post has a minimum dimension along the second transverse axis at a location that is spaced apart from the first end of the post.

In some embodiments, the post has a minimum dimension along the first transverse axis at the post second end.

In some embodiments, the first dimension corresponds to a diameter of the through hole.

In some embodiments, the first end of the post has a first dimension along a first transverse axis that is transverse to the longitudinal axis, and a second dimension along a second transverse axis that is transverse to the longitudinal axis and the first transverse axis, where the second dimension is less than the first dimension.

In some embodiments, a portion of a surface of the post that faces the beam is angled relative to the longitudinal axis such that the portion of the surface of the post is parallel to a surface of the beam that faces the post.

In some embodiments, the beam is a first beam, and the fastener comprises a second beam disposed on a side of the post that is opposed to the first beam.

In some embodiments, the first beam and the second beam reside in a plane that includes the second transverse axis and the longitudinal axis.

In some embodiments, the beam free end is parallel to the second side of the flange.

In some aspects, an actuator such as those used to adjust seat position within a vehicle includes an electric motor and a gear set that connects the drive motor to the vehicle seat and transmits the output of the motor to the vehicle seat. The drive motor and gear set are each disposed in an individual, dedicated housing component. The individual housing components are then assembled together to provide the actuator. The housing components are maintained in the assembled configuration using snap fit mechanical fasteners. Use of snap-fit mechanical fasteners can be advantageous since the snap fit fastener components may be formed integrally with the corresponding housing components in an injection molding process. In addition, fewer parts are included in the assembly and housing assembly is simple and can be performed without tools.

In some aspects, the snap-fit fastener includes a receiving portion provided on one housing component (for example, the drive motor housing) and a retaining portion provided on the other housing component (for example, the gear housing). The receiving portion may be a through hole formed in the drive motor housing, while the retaining component protrudes from an outer surface of the gear housing. In use, the retaining portion is inserted into the receiving portion, engages the receiving portion and forms a snap-fit engagement with the receiving portion. Advantageously, since the receiving portion comprises a through hole, the screw holes previously provided in the drive motor housing can be repurposed to form a portion of the snap-fit fastener. As a result, minimal or no redesign of the drive motor housing is required to implement the snap-fit fastener as a securing mechanism.

In some aspects, the retaining portion of the snap-fit fastener includes a post that protrudes from an outer surface of the gear housing, and a beam that is cantilevered from a free end of the post so as to overlie the post and extend at an acute angle relative to a longitudinal axis of the post. The retaining portion, which protrudes from an outer surface of the gear housing and thus is somewhat exposed, includes structural features that enhance stability and durability of the retaining portion and reduce likelihood of damage during assembly and handling of the actuator. The structural features include providing additional material at a location that experiences a large bending moment upon impact to the post, for example at the base of the post. In addition, the base of the post has a diameter that corresponds to a diameter of the through hole, whereby the post is stably received in the through hole.

DETAILED DESCRIPTION

Referring toFIGS. 1 and 2, an actuator1such as those used to adjust the position of a vehicle seat5may include an electric drive motor10, and a gear set20that is disposed between the drive motor10and vehicle seat5. The gear set20transmits the output of the drive motor10to the vehicle seat5. The drive motor10and the gear set20are housed in an actuator housing2. The actuator housing2includes a gear housing22that receives the gear set20and supports the gear set20for rotation. The actuator housing2also includes a drive motor housing12that is formed separately from the gear housing22, and is attached thereto during assembly of the actuator1. The drive motor housing12is joined to the gear housing22at one end thereof using snap fit mechanical fasteners30, as discussed in detail below.

Referring toFIG. 3, the drive motor housing12is a cup-like enclosure that includes a sidewall14having a closed end13. The open end15of the sidewall14is opposed to the closed end13, and is surrounded by a flange16. The flange16protrudes outwardly from an outer surface of the sidewall14. The flange16has a first side16athat faces the gear housing22and a second side16bthat is opposed to the first side16a. The flange first and second sides16a,16bare parallel to the closed end13. The flange16includes a pair of ears17, which are regions of expanded area that are formed on diametrically opposed sides of the open end15. Each ear17of the flange16is provided with a through hole18that extends between the flange first side16aand the flange second side16b. The through holes18form one part (e.g. a receiving portion40) of the fastener30, as discussed further below.

The gear housing22includes a container24that receives the gear set20, and a cover25that closes an open end of the container24. The gear housing22also includes a fixture26that is provided at one end of the container24and that is configured to enable the gear housing22to form a secure and stable connection with the drive motor housing12. The fixture26defines a wall portion27that protrudes outward from an outer surface23of the container24and has a profile or shape that is similar to that of the drive motor housing sidewall14. The fixture wall portion27include a pair of bosses28that are formed on diametrically opposed sides of the fixture wall portion27. The bosses28are positioned to be aligned with, and abut, the ears17of the drive motor housing flange16upon assembly of the drive motor housing12with the gear housing22. In addition, the bosses28support another part (e.g., a retaining portion60) of the fastener30, as discussed further below.

Referring toFIGS. 4-11, the actuator housing2includes two snap fit mechanical fasteners30. Each fastener30includes the receiving portion40, and the retaining portion60that forms a snap-fit engagement with the receiving portion40. In the illustrated embodiment, the receiving portion40is provided on the drive motor housing12, and the retaining portion60is provided on the gear housing22, but the fastener30is not limited to this configuration. For example, in other embodiments, the receiving portion40is provided on the gear housing22, and the retaining portion60is provided on the drive motor housing12.

The receiving portion40is an opening in the sidewall of the drive motor housing12. In particular, the receiving portion40is a flange through hole18.

The retaining portion60protrudes from an outer surface of the gear housing22. In particular, the retaining portion60protrudes from a boss28of the fixture wall portion27. The retaining portion60protrudes toward the drive motor housing12, and includes an elongated post61and a pair of beams68that are cantilevered from the post61. The post61includes a post first end62that is fixed to or formed integrally with the end face29of the boss28, and a rounded post second end63that is opposed to the post first end62and spaced apart from the boss28. In addition, the post61includes a longitudinal axis64that extends through both the post first end62and the post second end63and is perpendicular to the boss end face29.

The post first end62has a generally oval shape when viewed in cross section (FIG. 5), and thus has a first dimension d1along a first transverse axis65, and a second dimension d2along a second transverse axis66, where the first transverse axis65is perpendicular to the longitudinal axis64and the second transverse axis66is perpendicular to both the longitudinal axis64and the first transverse axis65. The first dimension d1of the post first end62is set to correspond to be the same as, or slightly smaller than, a corresponding dimension dh of the through hole18. By fitting the first dimension d1to the dimension dh of the through hole18along the first transverse axis65, movement of the post61relative to the through hole16is minimized and thus the fastener30is made stable. The second dimension d2is less than the first dimension d1. The space between the post61and the through hole18along the second transverse axis66provides room for the beams68to deflect toward the post61during insertion of the post61into the through hole18, as discussed further below.

2a. In addition, the post first end62has a third dimension d3along a second transverse axis66that is perpendicular to the longitudinal axis64and to the first transverse axis65, and the third dimension d3is less than the first dimension d1.

In order to provide a robust structure that resists damage, due, for example, to an impact load, which can occur during handling and assembly, the post61is tapered along the longitudinal axis64so as to be widest at the post first end62. When seen in side view as viewed in the direction of the second transverse axis66(FIG. 9), the post61is tapered adjacent the post second end63, has a maximum dimension d1at the post first end62and has a minimum dimension d3at the post second end63. When seen in side view as viewed in the direction of the first transverse axis65(FIG. 10), the post61is tapered adjacent the post first end62, and has a minimum dimension d4at a mid-portion of the post61.

The retaining portion60includes two beams68. The beams68are elastic, elongated, flat plates, and have a generally rectangular shape when viewed in the direction of the second transverse axis66(FIG. 9). The beams68are arranged so that a beam68is provided on each of opposed sides of the post61. In the illustrated embodiment, the beams68reside in a plane defined by the second transverse axis66and the longitudinal axis64. Each beam68includes a beam fixed end69that extends from the post second end63, and a beam free end70that is spaced apart from the beam fixed end69. The beams have uniform dimensions d5, d6from the beam fixed end69to the beam free end70. In addition, the beam free end70is spaced apart from, and parallel to, the boss end face29. The spacing between the beam free end70and the boss end face29corresponds to a thickness of the flange16.

Each beam68is cantilevered from the post second end63so as to overlie the post61. More specifically, each beam68extends at an acute angle θ relative to the longitudinal axis64(FIG. 10), whereby the beam free end70is spaced apart from the longitudinal axis64a distance that is greater than half the dimension dh of the through hole18(e.g., greater than the through hole radius). That is, a dimension d7between the beam free ends70is greater than the dimension dh of the through hole18, and is greater than the first and second dimensions d1, d2of the post first end62. In addition, a portion67of the surface of the post61that faces the beam68is angled relative to the longitudinal axis64such that the portion67of the surface of the post61is parallel to a surface71of the beam68that faces the post61.

During assembly of the gear housing22with the drive motor housing12, the post61is inserted into the receiving portion40, e.g., into the through hole18. Since the beam free end70is spaced apart from the longitudinal axis64a distance that is greater than a radius r of the through hole18, as the post61advances through the through hole18, the edges of the flange16defined by through hole18urge the beams68to deflect radially inward toward the longitudinal axis64, whereby the retaining portion60radially contracts.

When the gear housing22is fully assembled with the drive motor housing12, the post61extends through the through hole18. In this position, the outer surface of the gear housing (e.g., the boss end face29) abuts the flange first side16a. In addition, the post61protrudes outward relative to the flange second side16b, whereby the post second end63is spaced apart from the flange16. Further, the beams68, which have passed through the through holes18, elastically return to an expanded configuration whereby the beam free end70is spaced apart from the longitudinal axis64and faces the flange second side16b. The retaining portion60is retained in connection with the receiving portion40via engagement of the beam free ends70with the flange second side16b, which prevents withdrawal of the post61from the through hole18.

In the illustrated embodiment, the actuator housing2includes two snap-fit fasteners30. It is understood, however, that a greater or fewer number of fasteners30can be used to join housing components together, and the number of snap-fit fasteners30used is determined by t requirements of the specific application.

Selective illustrative embodiments of the housing and fasteners are described above in some detail. It should be understood that only structures considered necessary for clarifying the housing and fasteners have been described herein. Other conventional structures, and those of ancillary and auxiliary components of the housing and fasteners, are assumed to be known and understood by those skilled in the art. Moreover, while a working example of the housing and fasteners have been described above, the housing and fasteners are not limited to the working examples described above, but various design alterations may be carried out without departing from the housing and fasteners as set forth in the claims.