Vehicle seat fold mechanism

A vehicle seat assembly has a seat base, a seat back rotatably connected to the seat base and movable between an upright position and a folded position. An arm has a first end region connected to the seat base and a second end region defining a cam surface. A follower such as a pin is connected to the seat back and fixed relative thereto. The follower engages the cam surface when the seat back is in the folded position.

TECHNICAL FIELD

The disclosure relates to a mechanism for a vehicle seat assembly having a walk in or easy entry mechanism.

BACKGROUND

A vehicle seat assembly may be provided with a mechanism to fold the seat back relative to the seat base. Examples of seat folding mechanisms are disclosed in U.S. Pat. No. 8,777,314, PCT Pub. No. WO05/108152 A2, and German Pat. No. DE102011012562 B4.

SUMMARY

In an embodiment, a vehicle seat assembly is provided with a track adapted to be mounted to a vehicle, and a seat base mounted to the track to translate thereon. A seat back is rotatably connected to the seat base and being movable between an upright position and a folded position. An arm is rotatably coupled to one of the seat base and the seat back, with the arm defining a cam surface. A spring member is connected to the arm and the one of the seat base and the seat back. A follower is connected to the other of the seat base and the seat back, with the follower engageable with the cam surface of the arm when the seat back is pivoted between the folded position and the upright position. A seat release mechanism is connected to the seat back, to release the seat back from the upright position and cause the seat base to translate along the track. The seat back is disengaged from the upright position through actuation of the seat release mechanism. The seat back is reengaged to the upright position by moving the seat back relative to the seat base without actuating the seat release mechanism. The cam surface is shaped such that the seat base translates with respect to the track before the seat back rotates towards the upright position with respect to the seat base.

In a further embodiment, the spring member biases the arm in a first direction. The cam surface defines a convex transition region positioned between a backdrive region and a locking region. The spring member is further compressed, and the arm is rotated in a second direction opposite to the first direction, in response to engagement of the follower with the transition region.

In an even further embodiment, the follower sequentially engages the locking region, the transition region, and the backdrive region as the seat back is pivoted from the folded position to the upright position.

In another embodiment, a vehicle seat assembly is provided with a seat base, and a seat back pivotally connected to the seat base and movable between an upright position and a folded position. An arm has a first end region connected to the seat base and a second end region defining a cam surface. A follower is connected to the seat back and fixed relative thereto, with the follower engaging the cam surface when the seat back is in the folded position.

In a further embodiment, a biasing member is connected to the seat base and the arm to rotationally bias the arm in a first direction. The biasing member is compressed in response to the follower engaging the cam surface such that the arm is rotated in a second direction opposite to the first direction.

In an even further embodiment, a range limit is connected to the seat base, the range limit positioned to contact the arm when the seat back is in the upright position and the follower is spaced apart from arm and the cam surface such that the range limit limits movement of the arm in the first direction.

In another even further embodiment, the cam surface has a first portion and a second portion, with the second portion positioned between the first portion and the first end region.

In a yet even further embodiment, the biasing member is further compressed to move the arm in the second direction during a transition when the follower moves between the first portion and the second portion of the cam surface.

In another yet even further embodiment, the follower engages the first portion in response to the seat back moving towards the folded position to move the arm in the second direction opposite to the first direction. The follower engages the second portion when the seat back is in the folded position. The follower engages the second portion in response to the seat back moving towards the upright position to move the arm in the second direction.

In a yet even further embodiment, at a location of engagement of the follower, the first portion of the cam surface is oriented at a backdrive angle. The backdrive angle is defined as an angle between an arm line and a normal line, with the arm line extending from the location of engagement to a pivot point of the arm, and the normal line extending perpendicularly to the first portion at the location of engagement. The backdrive angle is less than ninety degrees such that engagement of the follower with the first portion causes the arm to move in the second direction without binding.

In another yet even further embodiment, at a location of engagement of the follower when the seat back is in the folded position, the second portion of the cam surface is oriented at a locking angle. The locking angle is defined as an angle between an arm line and a normal line, with the arm line extending from the location of engagement to a pivot point of the arm, and the normal line extending perpendicularly to the second portion at the location of engagement. The locking angle is within a range of ten to thirty degrees such that engagement of the follower with the second portion maintains the position of the arm to maintain the seat back in the folded position while the seat base is translated rearward.

In still yet even further embodiment, the locking angle is further defined as being within a range of fifteen to twenty degrees.

In a yet even further embodiment, from the folded position, the seat back is pivotable relative to the seat base with a force imparted on the seat back, such that the follower travels along the second portion of the cam surface and then along the first portion of the cam surface as the seat back is moved towards the upright position relative to the seat base.

In another further embodiment, a seat release mechanism is connected to the seat back. The seat release mechanism is actuatable to release the seat back to pivot relative to the seat base from the upright position toward the folded position. The seat back is pivotable from the folded position toward the upright position without requiring actuation of the seat release mechanism.

In an even further embodiment, a sliding track mechanism is connected to the seat base and the seat release mechanism. The seat release mechanism is actuatable to translate the seat base relative to the sliding track mechanism. The follower is engagable with the cam surface to maintain the seat back in the folded position while the seat base is translated rearward with respect to the sliding track mechanism, such that the seat base translates with respect to the sliding track mechanism before the seat back pivots towards the upright position.

In a further embodiment, the arm has a bracket extending from a first end to a second end, with the first end of the bracket forming the first end of the arm and rotatably connected to the seat base. The arm has a leaf spring having a first end region connected to a second end of the bracket, with a second end region defining the cam surface and an intermediate region extending between the first and second end regions. The cam surface is defined as a concave surface positioned between a convex surface and the intermediate region of the leaf spring.

In an even further embodiment, the arm has an elastomeric element connected to the leaf spring and positioned to contact the first end region and the intermediate region of the leaf spring when compressed.

In a yet even further embodiment, the first end region and the intermediate region are substantially parallel to one another. The elastomeric element is positioned to contact the second end region of the leaf spring when compressed.

In a still yet even further embodiment, the elastomeric element is spaced apart from second end region of the leaf spring.

In an embodiment, a vehicle seat assembly is provided with a seat base, and a seat back pivotally connected to the seat base and movable between an upright and a folded position. An arm extends from a first end region to a second end region, with the first end region rotatably connected to one of the seat base and the seat back. The second end region defines a cam surface having a concave section positioned between a convex section and the first end region. A pin is connected to the other of the seat base and the seat back and fixed relative thereto, with the pin engaging the cam surface when the seat back is in the folded position.

DETAILED DESCRIPTION

FIG. 1illustrates a vehicle seat assembly10having a seat back12, a seat base14, a sliding track mechanism11, and a seat release mechanism16. The seat back12is pivotally connected to the seat base14such that the seat back12can fold, pivot, or rotate forward to allow for ingress to or egress from a vehicle seat assembly or seating row positioned aft of the vehicle seat assembly10in a vehicle, to provide storage of items over the seat back, or the like. For example, the vehicle seat assembly10is in the front of the vehicle for a driver or passenger, and the seat back12is pivoted or folded forward about a pivotal axis18to allow a passenger to get into or out of a rear seating row or to access cargo in a rear seating row of the vehicle. Alternately, the folding mechanism16may be used with a vehicle seat assembly10in a second row of seats to gain access to a third row. According to further examples, the vehicle seat assembly10may be provided as a front row seat in a two-door or three-door vehicle, or as a second row seat in a four-door or five-door vehicle.

As illustrated inFIG. 1, the seat base14may also translate along the sliding track mechanism11in the fore/aft direction13. For example, the seat release mechanism16has a lever, handle, or other mechanism, that a user engages to release the seat back12and allow the seat back12to pivot, or fold forward, with respect to the seat base14. The seat release mechanism16may be connected to the sliding track mechanism11by a linkage, such as a Bowden cable, or the like. As the seat back12folds forward, the linkage is tensioned, or otherwise engaged, such that the sliding track mechanism11is released and the seat base14slides forward on the tracks19. This combination of the seat back12pivoting and the seat base14sliding forward provides additional clearance to the area in a vehicle behind the seat10, i.e. to a second row of seats, and places the seat10in a walk in configuration or easy entry configuration.

The seat back12is movable between an upright position as shown inFIG. 1in broken lines, and a folded position with the seat back12pivoted towards the seat base14about the axis18. When the seat back12is in a folded position, the seat base14translated in a forward direction along axis13. The degrees of pivotal motion and amount of translational motion of the seat10may vary based on the design criteria for the vehicle seat assembly10and the clearance permitted by the structure of the seat back12and the seat base14and the vehicle. For example, the seat back12may fold approximately forty-five degrees as shown, although a range of motion through more than or less than forty-five degrees is also contemplated for the seat back. The seat back12may additionally be positioned at other seat back angles selected by the user, for example, at a greater degree of recline.

In the prior art, to return the seat back12to the upright position, the user would need to activate one or more mechanisms. For example, in various prior art, the user unfolds the seat back12and places it in the upright position by activating a lever or other input to the seat release mechanism. The seat base14remained locked in the forward position, and the sliding track mechanism also needed to be activated by the user to slide the seat base14rearward along the tracks11to the starting or use position.

FIG. 2illustrates an embodiment of a seat release mechanism16for use with a vehicle seat assembly10in a partially exploded view. The seat release mechanism16is located at the junction of the seat back12and the seat base14. The seat release mechanism16may contain features to provide for various recline angles of the seat back12with respect to the seat base14as are known in the art.

The seat release mechanism16has an arm20defining a cam surface22. The arm20is pivotally connected to a bracket24that is connected to or formed as a part of the seat base14. The arm20may be pivotally connected to the bracket24via aperture28defined by the bracket using a pivotal connection26such as a bushing and pin or rivet. The arm20pivots or rotates about a pivot point defined by axis30.

A spring element, or biasing element32has one end connected to the arm20, and the other end connected to the bracket24, for example, via aperture34. The spring member32may be a torsion spring according to an embodiment; although other spring members are also contemplated. The spring member32biases the arm20in a first direction36. If the arm is moved in a second direction38, the spring member32is compressed.

A first pin40or a stop pin40is connected to and fixed relative to the bracket24. The stop pin40may be connected to the bracket24via an aperture42formed in the bracket24. The pin40is positioned to limit travel or movement of the arm20in the first direction36. The stop pin40may be provided as a separate pin or other range limit element, or may be integrally formed, e.g. as a stamping or other protrusion on the bracket24.

A second pin44or a locking pin44is connected to and fixed relative to a bracket46that is connected to or formed as a part of the seat back12. The locking pin44may be provided as a follower. The locking pin44may be connected to the bracket46via an aperture48formed in the bracket46. The pin44therefore moves with the seat back12relative to the seat base14and the arm20. The locking pin44or follower may be provided as a separate pin or other follower element, or may be integrally formed, e.g. as a stamping or other protrusion on the bracket24.

The pin44is engageable with the cam surface22of the arm20when the seat back12is moved between the folded position and the upright position relative to the seat base14. The cam surface22follows the pin44as the seat back12pivots with respect to the seat base14. The spring member32is compressed in response to the pin44engaging the cam surface22such that the arm20is rotated in a second direction38opposite to the first direction.

The stop pin40is positioned to contact the arm20when the seat back12is in the upright position and the locking pin44is spaced apart from arm20and the cam surface22such that the stop pin40limits movement of the arm20in the first direction36.

In an alternative embodiment ofFIG. 2, the arm20, the spring member32, and the pin40may be provided on the seat back12, while the pin44is provided on the seat base14.

Referring toFIGS. 2-4, the features of the seat release mechanism16are described in greater detail. The arm20has a first end region50and a second end region52. The first end region50is rotatably connected to the seat base14via pivotal connection26. The second end region52defines the cam surface22. The cam surface22has a first portion54and a second portion56, with the second portion56positioned between the first portion54and the first end region50. The first portion54is therefore farther from the first end region50than the second portion56, and closer to the second end52of the arm. The first portion56may be referred to as a backdrive portion54. The second portion56may be referred to as a locking portion56. The second portion56may form a concave section or region with the adjacent structure of the arm20.

A transition region58is positioned between and directly adjacent to the first and second portions54,56. The transition region58may be provided by a convex shape. The first and/or the second sections54,56may be linear, concave arcuate, convex arcuate, or another profile shape as is known in the art. The pin44sequentially engages the locking region56, the transition region58, and the backdrive region54as the seat back12is pivoted from the folded position to the upright position. The pin44sequentially engages the backdrive region54, the transition region58, and the locking region56as the seat back12is pivoted from the folded position to the upright position.

As the profile of the cam surface22changes, the amount of force, or the amount of compression of the spring32, changes as the pin44moves relative to the cam surface22. For example, the pin44moving over the transition region58between the first portion54and the second portion56involves a large amount of compression of the spring32over a short distance of the cam surface22, since it is a steep profile and a convex shape.

The pin44engages the first portion54in response to the seat back12moving towards the folded position to move the arm20in the second direction38opposite to the first direction. The pin44engages the second portion56when the seat back12is in the folded position. The pin44engages the second portion56in response to the seat back12moving from the folded position and towards the upright position to move the arm in the second direction38until the pin44reaches the transition region58.

The first portion54and the second portion56of the cam surface22are each provided with a specified angle to provide the required backdrive motion and unlocking motion of the arm. The first and second portions54,56are shaped to prevent binding of the seat back as it moves, and are furthermore shaped to provide a desired force to move the arm and seat back.

The first portion54of the cam surface, or backdrive portion, is oriented at a specified angle or backdrive angle β. When the pin44first engages or contacts the backdrive region54, the first portion54of the cam surface at the location of engagement with the pin44is oriented at the backdrive angle β. The backdrive angle β is defined as an angle between an arm line60and a normal line62. The arm line60extends from the location of engagement with the pin44to a pivot point of the arm20. The normal line62extends perpendicularly to the first portion54at the location of engagement of the pin44. The backdrive angle β is shown inFIG. 3, and is the smaller of the angles formed between the normal line62and the arm line60. According to one example, the backdrive angle β is less than ninety degrees. In another example, the backdrive angle is within a range of 20-85 degrees. In a further example, the backdrive angle β is within a range of 20-50 degrees. The first section54may extend colinearly or substantially colinearly with the location of engagement of the pin44and at the backdrive angle β as shown. For purposes of the disclosure, “substantially” may lie within a range of plus or minus two degrees, plus or minus five degrees, or plus or minus ten degrees of the specified angle.

The second portion56of the cam surface, or locking portion56, is oriented at a specified angle or locking angle λ. When the pin44engages or contacts the locking region56with the seat back12in the folded position, the second portion56of the cam surface at the location of engagement with the pin44is oriented at the locking angle λ. The locking angle λ is defined as an angle between an arm line70and a normal line72. The arm line70extends from the location of engagement of the pin44to a pivot point of the arm20. The normal line72extending perpendicularly to the second portion56at the location of engagement of the pin44. The locking angle λ is shown inFIG. 4, and is the smaller of the angles formed between the normal line72and the arm line70. According to one example, the locking angle λ is within a range of seven to thirty degrees. In a further example, the locking angle is within a range of fifteen to twenty degrees. The second section56may extend colinearly or substantially colinearly with the location of engagement of the pin and at the locking angle λ as shown.

The mechanism16and vehicle seat assembly10as shown inFIGS. 1-4provides for a release of the seat back12into a folded position, for example, for easy entry, and also provides for a simplified return to the upright, use position of the seat back12by the user.

According to an example, a seat release mechanism16for the vehicle seat assembly is actuated to release the seat back12from the upright position and cause the seat base14to translate along the track. The actuation of the seat release mechanism16disengages the seat back12from the upright position such that the seat back12begins to move towards the folded position. A spring member in the seat release mechanism, as well as the mass of the seat back, may cause the seat back to automatically move to the folded position in response to the seat release mechanism being actuated, e.g., the pin44will move the arm20and engage the locking section56. Actuation of the seat release mechanism may additionally cause the vehicle seat10to slide forward along the track to provide a larger space behind the seat.

To return the vehicle seat10to a use position with the seat back12in the upright position, the seat back12is reengaged to the upright position by moving the seat back12relative to the seat base14without actuating the seat release mechanism. The cam surface22is shaped to engage with the locking pin44such that the seat base14translates with respect to the track before the seat back12pivots towards the upright position with respect to the seat base.

As the seat back12is rotated towards the folded position from the upright position, the pin44comes into contact or engagement with the first, backdrive portion54of the cam surface22, as is shown inFIG. 3. As the seat back12is rotated further towards the folded position, the locking pin44causes the arm20to move in the second direction38and away from the stop pin40. This motion may be referred to as a back-driving motion of the arm20. The arm20continues to rotate in the second direction38as the locking pin44moves along the first portion54of the cam surface.

The locking pin44then passes the transition region58on the cam surface22, and begins to move along the second, locking portion56. As the pin44moves along the locking portion56while the seat back12continues to move towards a folded position, the arm20moves in the first direction36based on the cam surface22shape. When the seat back12is in the folded position, the locking pin44is engaged with the locking portion56of the cam surface22as shown inFIG. 4.

To move the seat back from the folded position to the upright position, the user pulls or moves the seat back12towards the upright position, and without operating a lever or other user input associated with the seat release mechanism. In one example, the user may exert a force on the seat back12near an upper shoulder support region to return the seat10from the easy entry position. The locking pin44engages and imparts a force on the locking portion56of the cam surface, and moves the arm20in the second direction38. The locking pin44moves along the locking portion56until it reaches the transition region58and further compresses the spring32. Once the locking pin44passes the transition region58, the shape of the backdrive section54of the cam surface22allows the arm20to begin rotating in the first direction36. The locking pin44travels along the backdrive section54of the cam until the seat back12is unfolded sufficiently such that the locking pin44begins to move away from the arm20. The arm20engages the stop pin40to limit or prevent further movement or rotation of the arm in the first direction36and orient the backdrive section54of the cam surface for engagement with the locking pin44in a future folding motion.

When the seat back12is in the folded position, or not in the upright position, the seat back12is freely pivotable by a user without interacting with a lever or input to the seat release mechanism16. For example, when the seat back12is in the folded position, and the pin44is somewhere along the cam surface22, the user can move the seat back12relative to the seat base14and or the seat base14relative to the tracks19by only imparting a force on the seat back12.

When returning the seat back12to the upright position, the pin44engages with the cam surface22to maintain the seat back12in the folded position while the seat base14is translated rearward with respect to the sliding track mechanism, such that the seat base14translates with respect to the sliding track mechanism before the seat back12pivots towards the upright position. When the seat10no longer travels rearward along the tracks and the seat base14is locked in position, the pin44moves the arm20and the seat back12moves to the upright position. The force provided by the spring32and the shape of the cam surface22delays the seat back12from unfolding, and allows the seat base14to travel rearward along the tracks19such that the seat base14reaches a locked position in the tracks19before the seat back12begins to pivot to an upright position. When the seat back12reaches the upright position, it is then locked by the seat recline mechanism16in the upright position. The movement of the seat back12, from the folded position to the upright position, may be therefore done without the user touching any portion of the seat assembly10except the seat back12. The user does not have to actuate or interact with a lever for the seat release mechanism16to reposition the seat10from a folded or non-upright position to the upright position, or interact with a handle, or other mechanism, for the seat track mechanism11, thereby simplifying the operation for the user. For example, the seat back12is movable relative to the seat base14, and the seat base14is movable relative to the tracks19, when a force is imparted on the seat back12by a user, unless the seat is in the locked upright position.

Referring toFIGS. 5-7, another embodiment of a mechanism for use in the seat release mechanism16is illustrated, and provides operation of the vehicle seat10, e.g., a soft locking feature when the seat is in the easy entry, folded position as described above. An arm assembly100replaces the arm20and the spring32shown inFIGS. 2-4. Elements inFIGS. 5-7that are the same as or similar to those shown inFIGS. 1-4have the same reference numbers as those used above for simplicity.

Referring toFIGS. 5-6, the arm100has a first end region102rotatably connected to the seat base and a second end region defining a cam surface104. The arm100is configured to provide a compressive force when the cam surface is biased away from the pin

The arm100has a bracket106extending from a first end to a second opposite end, with the first end of the bracket forming the first end102of the arm and being connected to the seat base14or seat base bracket14. The bracket106itself may act as a spring member as it is provided with a structure similar to that of a cantilever beam, with the second end of the bracket not connected to the seat base.

The arm100has a spring member110with a first end region112connected to a second end of the bracket, and a second end region114defining the cam surface104. An intermediate region116extends between the first and second end regions112,114. In one example, spring member110is a leaf spring. The spring110may be a leaf spring, or other spring as is known in the art. The spring member110may be curved such that the first and second end regions112,114are adjacent to one another, and the spring resembles a U-shape with the first end region112and the intermediate region116being substantially parallel to one another.

An elastomeric element120or damper may be positioned within the spring member110such that it is in contact with the spring member110. The elastomeric element120may be positioned to contact the first end region112and the intermediate region116of the leaf spring when compressed. The damper120is placed within the interior of the spring member110to damp the motion of the spring member and/or provide additional resistance to compression. For example, the damper120is positioned on an internal side of the spring member110. The damper120may be connected to the spring member110using molded in clips, an adhesive, a mechanical fastener, or otherwise as is known in the art. For example, the damper120is an elastomeric block, such as rubber, which may be shaped to correspond with the shape of the spring member110.

In one example, the elastomeric element120extends towards and is positioned to additionally contact the second end region114of the leaf spring110when compressed as shown inFIGS. 5-6. In another example, and as shown inFIG. 7, the elastomeric element120is spaced apart from second end region114of the leaf spring such that it is only positioned to contact the first end region112and the intermediate region116.

The second end region114of the spring member110defines the cam surface104or locking section. The cam surface104may be defined as a concave surface130positioned between a convex surface132and the intermediate region116of the leaf spring. The locking pin44is connected to the seat back12and fixed relative thereto, and the pin44engages the cam surface104when the seat back12is in the folded position as shown inFIGS. 6-7. In one example, and as shown, the locking pin44engages the cam surface when the seat back is in the folded position. The locking pin44may engage the cam surface104and retain the seat back12in the folded position based on a combination of the compressive force cause by the leaf spring110structure and shape of the cam surface104, as well as frictional engagement with the cam surface. The resistance of the pin44exiting the cam surface with the seat back12unfolding is higher than the sliding resistance of the seat base14along the tracks19, thereby causing the seat base14to translate before the seat back12rotates. Once the seat base14is locked into position on the tracks19by the mechanism11, the force exerted by the user on the seat back12will cause the pin44to exit the cam surface104as the seat back return to the upright position. When the pin44is engaged with the cam surface104, the seat back12may be moved without any actuation of an associated seat release mechanism16or sliding track mechanism11. The user may simply move the seat back12and/or the seat base14by imparting a force directly on the seat back12.

As shown inFIGS. 6-7, the shape of the cam surface104, the concave section130and the convex section132may vary.