ROTARY RECLINER ASSEMBLY TECHNICAL FIELD

The subject matter described herein, in general, relates to automotive seat recliners and in particular, relates to a rotary recliner assembly having a plurality of roller blocks operable for permitting desired position of a seat backrest over a wide range of reclining positions. BACKGROUND

A vehicle seat assembly plays an important role in the vehicle's aesthetics and passenger's comfort. Conventional vehicles have different types of seats, such as a front seat, a rear seat, a bench seat, a split seat depending on the targeted customer usage pattern. The seats of the vehicle include a seat backrest and a seat cushion.

The vehicle is provided with a reclining mechanism for its seats that enables an occupant of the vehicle to adjust the angle of inclination of the seat backrest with respect to the seat cushion and then lock it up at the desired angle. The reclining mechanism also acts as a safety component that withstands and absorbs impact energy in the event of a collision of the vehicle. The seat recliner mechanism is generally of two types. They are concentric rotary recliner assembly and eccentric rotary recliner assembly.

In case of the eccentric rotary recliner assembly, there are two requirements to be met for actuating the eccentric rotary recliner assembly. The first requirement is to achieve a minimum of one gear teeth difference between the upper gear and the lower gear. The second requirement is to achieve eccentricity i.e. the centre of an upper gear and the centre of a lower gear of the eccentric rotary recliner assembly need to be offset to each other.

Eccentric motion and the locking between the lower gear and the upper gear are achieved by providing a pair of wedges. These wedges are forced apart by a spring. In such a case, all the contact surfaces of the upper gear and the lower gear require a fine surface finish or special coated surface in order to avoid friction. Such high surface finish and special coated surface often adds the overall expenditure rendered in the rotary recliners for the seat of the vehicle. Also, the surface contact achieved between the wedges and the surfaces of the upper gear and the lower gear requires more operating effort and further produces noise, causing discomfort to the occupant of the vehicle.

There is therefore a need for a rotary recliner assembly for a seat of a vehicle with improved meshing capabilities, lower operational effort and improved structural features without compromising in the manufacturing cost of the rotary recliner assembly. Further, the noise generated due to the relative motion due to the surface contact needs to be minimized.

SUMMARY The subject matter described herein relates to a rotary recliner assembly having a plurality of roller blocks operable for permitting desired position of a seat backrest over a wide range of reclining positions.

According to one aspect of the present subject matter, the rotary recliner assembly for a seat of a vehicle comprises an upper gear and a lower gear. The upper gear has a first flange. The upper gear further includes a plurality of inwardly directed teeth on the inner periphery of the upper gear. The lower gear has a second flange. The lower gear further includes a plurality of outwardly extending teeth on the outer periphery of the lower gear for engagement with the plurality of teeth of the upper gear. A plurality of

roller blocks is disposed between the first flange of the upper gear and the second flange of the lower gear. Each of the roller blocks comprises a plurality of roller members. The rotary recliner assembly further includes one or more resilient members. Each of the resilient members connects two consecutive roller blocks. An elongated member is adapted to fit within the first flange of the upper gear. The elongated member comprises one or more flanged portions wherein at least one end of the flanged portion is in contact with one end of at least one of the roller blocks.

These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF DRAWINGS The above and other features, aspects, and advantages of the subject matter will become better understood with regard to the following description, appended claims, and accompanying drawings where:

Fig.l illustrates a front view of a rotary recliner assembly for a seat of a vehicle with respect to one embodiment of the present subject matter. Fig.la illustrates an exploded view of a rotary recliner assembly of Fig. 1.

Fig.2a illustrates a perspective view of the roller block assembly of the rotary recliner assembly with respect to one embodiment of the present subject matter.

Fig.2b illustrates a perspective view of a roller block assembly with respect to another embodiment of the present subject matter.

Fig.3a illustrates a schematic representation of a roller block assembly with a torsion spring with respect to one embodiment of the present subject matter. Fig.3b illustrates a schematic representation of a roller block assembly with a compression spring with respect to another embodiment of the present subject matter.

Fig.4 illustrates a perspective view of an elongated member of a rotary recliner assembly with respect to one embodiment of the present subject matter.

Fig.5 illustrates a perspective view of a rotary recliner assembly with respect to one embodiment of the present subject matter.

Fig.6a illustrates an initial non-rotated position of a rotary recliner assembly with a torsion spring with respect to one embodiment of the present subject matter.

Fig.βb illustrates an intermediate position of a rotary recliner assembly with a torsion spring with respect to one embodiment of the present subject matter. Fig.όc illustrates a final rotated position of a rotary recliner assembly with a torsion spring with respect to one embodiment of the present subject matter.

Fig.7a illustrates an initial non-rotated position of a rotary recliner assembly with a compression spring with respect to another embodiment of the present subject matter.

Fig.7b illustrates an intermediate position of a rotary recliner assembly with a compression spring with respect to another embodiment of the present subject matter.

Fig.7c illustrates a final rotated position of a rotary recliner assembly with a compression spring with respect to another embodiment of the present subject matter.

Fig.8 illustrates a perspective view of a roller block assembly having three-rollers with respect to yet another embodiment of the present subject matter. DETAILED DESCRIPTION

A rotary recliner assembly for a seat of a vehicle that satisfies the aforesaid need is described. The rotary recliner assembly comprises an upper gear and a lower gear. The upper gear is attached to an upper support member by means of fasteners, such as rivets. The upper gear is movable and has a first flange. A plurality of inwardly directed teeth is formed on an inner periphery of the upper gear. The lower gear is attached to a lower support member by means of fasteners, such as rivets. The lower gear has a plurality of outwardly extending teeth on an outer periphery of the lower gear for engagement with the plurality of teeth of the upper gear. The number of teeth of the lower gear is less than the number of teeth of the upper gear. Also, the diameter of the second flange is greater than the diameter of the first flange.

A plurality of roller blocks is disposed between the first flange and the second flange. Each of the roller blocks comprises a plurality of roller members of different sizes. The roller members can be selected from a group of cylindrical rollers or spherical balls. A resilient member, such as a torsion spring or a compression spring connects two consecutive roller blocks. The resilient member pushes the roller blocks apart to allow locking of the teeth of the upper gear with the teeth of the lower gear. An elongated member, such as a shaft is adapted to fit within the first flange of the upper gear. The elongated member comprises one or more flanged portions such that at least one end of one of the flanged portion is in contact with one end of at least one of the roller blocks

during assembly of the rotary recliner assembly. The elongated member further includes a base for supporting the flanged portions.

In accordance with one aspect of the present subject matter, the upper gear is attached to an upper support member by means of fasteners. In accordance with another aspect of the present subject matter, the upper gear is movable and said lower gear is stationary.

In accordance with another aspect of the present subject matter, the lower gear is attached to a lower support member by means of fasteners.

In accordance with another aspect of the present subject matter, number of teeth of the lower gear is less than the number of teeth of the upper gear.

In accordance with yet another aspect of the present subject matter, the diameter of the second flange is greater than diameter of the first flange.

In accordance with yet another aspect of the present subject matter, the resilient member is selected from a group comprising torsion spring and compression spring.

In accordance with yet another aspect of the present subject matter, the elongated member includes a base for supporting the flanged portion.

In accordance with yet another aspect of the present subject matter, the resilient member pushes the roller blocks apart to allow locking of teeth of the upper gear with teeth of the lower gear.

In accordance with yet another aspect of the present subject matter, the upper gear and the lower gear are eccentric to each other.

In accordance with yet another aspect of the present subject matter, the roller members are selected from a group comprising cylindrical rollers and spherical balls.

In accordance with yet another aspect of the present subject matter, the cylindrical rollers has a line contact while spherical balls have a point contact respectively with the first flange and the second flange.

In accordance with yet another aspect of the present subject matter, the roller members are of different sizes.

Fig.l illustrates a front view of a rotary recliner assembly 100 for a seat of a vehicle with respect to one embodiment of the present subject matter. The different components/ elements of the rotary recliner assembly 100 are explained below.

Fig.la illustrates an exploded view of the rotary recliner assembly 100 of Fig. 1. An upper support member 105 and a lower support member 110 are secured to a seat backrest and a seat cushion respectively. The rotary recliner assembly 100 is firmly held between the upper support member 105 and the lower support member 110. The rotary recliner assembly 100 includes an upper gear 115 attached to the upper support member 105 by means of fasteners, such as rivets. The upper gear 115 is provided with a first flange 120. A plurality of inwardly directed teeth 125 are formed on the inner periphery of the upper gear 115. The rotary recliner assembly 100 also includes a lower gear 130 attached to the lower support member 110 by means of fasteners, such as rivets. The lower gear 130 is provided with a second flange 135 that is compliant to accommodate the first flange 120 of the upper gear 115. A plurality of outwardly extending teeth 140 are provided on the outer periphery of the lower gear 130. The outwardly extending teeth

140 of the lower gear 130 engage with the inwardly directed teeth 125 of the upper gear 115. The number of teeth 140 of the lower gear 130 is less than the number of teeth 125 of the upper gear 115.

The rotary recliner assembly 100 further includes a roller assembly. The roller assembly includes a first roller block 145 and a second roller block 150. The first roller block 145 and the second roller block 150 are circumferentially mounted within the space formed between the first flange 120 of the upper gear 115 and the second flange 135 of the lower gear 130. In the present embodiment, the first roller block 145 comprises a plurality of cylindrical rollers 155. Each of the cylindrical rollers 155 of the first roller block 145 is of different size. Similarly, the second roller block 150 comprises a plurality of cylindrical rollers 155 of different sizes. The first roller block 145 and the second roller block 150 are connected to each other by a resilient member 160. An elongated member 165 is adapted to fit within the first flange 120 of the upper gear 115.

Fig.2a illustrates a perspective view of the roller assembly of the rotary recliner assembly 100 with respect to one embodiment of the present subject matter.

The roller assembly comprises the first roller block 145 and the second roller block 150. In the present embodiment, the first roller block 145 comprises two cylindrical rollers 155. Both the cylindrical rollers 155 of the first roller block 145 are of different sizes. Similarly, the second roller block 150 also comprises two cylindrical rollers 155 of different sizes. The difference in the sizes of the cylindrical rollers 155 of the first roller block 145 as well as of the second roller block 150 is provided for achieving the eccentricity between the upper gear 115 and the lower gear 130. A slot 205 is provided

on one of the ends of the first roller block 145. Another slot 210 is provided on one of the ends of the second roller block 150.

Fig.2b illustrates a perspective view of a roller assembly with respect to another embodiment of the present subject matter. The present embodiment comprises spherical balls 215 as roller members.

Fig.3a illustrates a schematic representation of the roller block assembly with a torsion spring with respect to one embodiment of the present subject matter. The first roller block 145 and the second roller block 150 of the roller block assembly are held together under torsion by means of a resilient member 160. In the present embodiment, the resilient member 160 is a torsion spring. The torsion spring is a single metal piece stretched circularly with two protruding ends placed side by side. The protruding ends of the torsion spring are inserted into the slots 205, 210 of both the first roller block 145 and the second roller block 150, thereby holding the first roller block 145 and the second roller block 150. The torsion spring in between the first roller block 145 and the second roller block 150 prevents the first roller block 145 and the second roller block 150 from coming in contact with each other. The torsion spring also enables complete meshing of teeth 125 of the upper gear 115 and the teeth 140 of the lower gear 130 at any given rotational position of the rotary recliner assembly 100.

Fig.3b illustrates a schematic representation of the roller block assembly with a compression spring with respect to another embodiment of the present subject matter. In the present embodiment, a compression spring is used as the resilient member 160 to hold the first roller block 145 and the second roller block 150.

Fig.4 illustrates a perspective view of the elongated member 165 with respect to one embodiment of the present subject matter. In one preferred embodiment, the elongated member 165 is a shaft. The elongated member 165 comprises one or more flanged portions. In the present embodiment, only one flanged portion 405 is provided. The flanged portion 405 has a curved profile and has a first end 410 and a second end 415. The elongated member 165 also includes a base 420 for supporting the flanged portion 405.

Fig.5 illustrates a perspective view of the rotary recliner assembly 100 along with the elongated member 165 with respect to one embodiment of the present subject matter. As shown in Fig.5, the elongated member 165 is adapted to fit within the first flange 120 of the upper gear 115. During assembling of the elongated member 165 within the rotary recliner assembly 100, the flanged portion 405 of the elongated member 165 fits within the space between the first flange 120 and the second flange 135. The flanged portion 405 of the elongated member 165 aligns with the first roller block 145 and the second roller block 150 within the space between the first flange 120 and the second flange 135. The elongated member 165 can be rotated clockwise or anticlockwise to actuate the rotary recliner assembly 100. Once the elongated member 165 is rotated, either the first end 410 of the flanged portion 405 comes in contact with the free end of the first roller block 145 or the second end 415 of the flanged portion 405 comes in contact with the free end of the second roller block 150 depending upon the direction of rotation of the elongated member 165.

Fig.6a illustrates an initial non rotated position of the rotary recliner assembly 100 with respect to one embodiment of the present subject matter. At the initial non

rotated position of the rotary recliner assembly 100, the seat backrest (not shown in the figure) is in upright position. As shown in the figure, the resilient member 160 is a torsion spring. The resilient member 160 holds the first roller block 145 and the second roller block 150. The meshing between the teeth 125 of the upper gear 115 and the teeth 140 of the lower gear 130 is observed during the initial position of the rotary recliner assembly 100. The meshing between the teeth also enables the rotary recliner assembly 100 to be stable during the upright position of the seat backrest

Fig.6b illustrates an intermediate position of the rotary recliner assembly 100 with respect to one embodiment of the present subject matter. At the intermediate position of the rotary recliner assembly 100, the seat backrest (not shown in the figure) is in intermediate reclining positions between the upright position and a fully reclined position. The torsion spring, holding the first roller block 145 and the second roller block 150, is subjected to torsion force during the rotation of the elongated member 165 in a clockwise direction. The first roller block 145 is pushed forward by the flanged portion (not shown in the figure) of the rotating elongated member 165, which in turn pushes the second roller block 150 forward.

Fig.6c illustrates a final rotated position of the rotary recliner assembly 100 with respect to one embodiment of the present subject matter. At the final rotated position of the rotary recliner assembly 100, the seat backrest (not shown in the figure) is in the fully reclined position. The first roller block 145 and the second roller block 150 are moved to a position, as shown in the Fig. 6c, in fully reclined position of the seat backrest. The meshing between the teeth is constantly achieved during all the three positions of the rotary recliner assembly 100 as depicted in Fig.6a, Fig.6b and Fig.6c, that is, during the

initial position, dynamic position and the final position. The set of teeth 125 of upper gear 115 and the set of teeth 140 of the lower gear 130 vary in number. The torsion spring enables constant meshing between the teeth 125 of the upper gear 115 and the teeth 140 of the lower gear 130. Fig.7a illustrates the initial position of the rotary recliner assembly 100 with respect to another embodiment of the present subject matter.

Fig.7b illustrates the intermediate position of the rotary recliner assembly 100 with respect to another embodiment of the present subject matter.

Fig.7c illustrates the final position of the rotary recliner assembly 100 with respect to another embodiment of the present subject matter.

As shown in Fig 7a, fig 7b, fig 7c, the resilient member 160 used is the compression spring. The compression spring is held between the first roller block 145 and the second roller block 150. The compression spring assists in achieving a constant meshing between the teeth 125 of the upper gear 115 and the teeth 140 of the lower gear 130 through all the three positions i.e. upright position, intermediate reclining position and the fully reclined position of the rotary recliner assembly 100. The compression spring enables the first roller block 145 and the second roller block 150 to be held together when being pushed during the rotation of the elongated member 165.

Fig.8 illustrates a perspective view of roller assembly having three rollers with respect to another embodiment of the present subject matter. The roller assembly 800 comprises two roller blocks, a first roller block 815 and a second roller block 820. The first roller block 815 comprises a first bracket 805 and a second bracket 810. The first bracket 805 and the second bracket 810 are attached at the ends by means of welding or

press fitting. The first bracket 805 and the second bracket 810 on attachment form a first roller block 145 of the roller assembly 800. Similarly, the second roller block 150 of the roller block assembly 800 is formed. The first bracket 805 and the second bracket 810 are made of cast iron or steel. The three rollers 155 of the roller assembly are of different sizes. The leading roller is the biggest of the three rollers 155, while the trailing roller 155 is the smallest roller between the three rollers 155. The intermediate roller 155 is of the size in between the size of leading and trailing rollers 155. All the three rollers 155 of the roller block assembly 800 are cylindrical in shape.

In one embodiment of the present subject matter, the teeth of the upper gear 115 and the lower gear 130 have involute profile. A stub profile of the upper gear 115 and the lower gear 130 can also be achieved in case of another embodiment of the present subject matter. The stub profile reduces the interference between the gear teeth.

The rotary recliner assembly 100 as disclosed in the present subject matter is robust, flexible, and possesses a high-strength with reduced number of components that are easy to manufacture and assemble. The rotary recliner assembly 100 of the present subject matter is also reliable and cost effective.

Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein.