GB2311094A

GB2311094A - Hinge assembly, e.g. for vehicle seat

Info

Publication number: GB2311094A
Application number: GB9605374A
Authority: GB
Inventors: Raymond Arthur Lloyd; Michael Paul Hyde
Original assignee: Adwest Johnson Controls Ltd
Current assignee: AJC Johnson Controls Ltd
Priority date: 1996-03-14
Filing date: 1996-03-14
Publication date: 1997-09-17
Anticipated expiration: 2016-03-14
Also published as: DE19710540A1; GB2311094B; DE19710540C2; GB9605374D0

Description

1 HINGE ASSEMBLY 2311094 The present invention relates to a hinge assembly

for a seat reclining mechanism, in particular but not exclusively a seat reclining mechanism for a vehicle seat.

It is known to provide a hinge assembly including a first hinge part hingedly connected to a second hinge part via a drive transmission assembly for angular movement about a hinge axis.

The drive transmission assembly includes a first hinge gear fixedly mounted on the first part, the first gear being eccentrically located within a ring gear fixedly mounted on the second hinge part. The first gear is eccentrically mounted on a drive shaft which is rotatably received in the second part for rotation about an axis co-axial with the ring gear.

Accordingly, rotation of the drive shaft causes the first gear to progress around the axis of the ring gear and in so doing causes the first gear to rotate about its own axis. Such rotation of the first gear causes angular displacement between the first and second hinge parts.

A problem associated with the type of hinge assembly described above is the degree of angular play between the first and second hinge parts. This play arises due to the working clearance between the first gear and the ring gear. It is highly undesirable to reduce the working clearance too much since to do so renders the drive shaft difficult to turn due to frictional resistance between the first and ring gears.

A general aim of the present invention is to provide a hinge assembly of the type described above wherein angular play between the first and second hinge parts is substantially eliminated and wherein, during 2 angular displacement of the first and second parts, frictional resistance is reduced in order to permit free and easy angular adjustment.

According to one aspect of the present invention there is provided a hinge assembly of the type described above wherein the first gear is eccentrically mounted on the drive shaft by an eccentric cam assembly comprising at least two concentrically arranged eccentric annuli rotatably mounted on the drive shaft, the annuli being biased for rotation in opposite directions and arranged such that relative rotation movement in said opposite directions causes an increase in the eccentricity of the first gear relative to the drive shaft, and so causes the first gear to move radially outwardly toward said ring gear, the drive shaft including drive means which on rotation of the drive shaft in a given direction initially causes one of the annuli to move in that given direction in order to move said one annuli against the bias and causes a decrease in the eccentricity of the first gear relative to the drive shaft and so causes the first gear to move radially inwardly away from said ring gears.

Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which Figure 1 is a side view of a hinge assembly according to one embodiment of the present invention, Figure 2 is a sectional view taken along line 11-H in Figure 1.

The hinge assembly 10 includes a first arm 12 which is pivotally connected to a second arm 14. In use, the first arm 12 will be attached to a vehicle scat back frame (not shown) and arm 14 will be attached to a vehicle seat cushion frame (not shown).

Arm 12 is preferably made from metal sheet and includes an 3 integrally formed ring gear 15 having radially inwardly directed gear teeth 19.

Arm 14 is also preferably made from metal sheet and includes an 5 integrally formed first gear 16 having radially outwardly directed teeth 20. Preferably the gears 15, 16 are each formed by a pressing operation.

The gear 16 is of smaller diameter than the ring gear 15 and is eccentrically located within the ring gear by an eccentric assembly 30.

The eccentric assembly 30 is rotatably mounted about a drive shaft 25 which is rotatably received in a bore 26 formed in the arm 12. The bore 26 is co-axial with the ring gear 16.

is Preferably, as shown in Figure 2, the bore 26 is formed within a sleeve 33 which is preferably integrally formed with the arm 12.

The eccentric assembly 30 includes a pair of eccentrically arranged eccentric annuli 35, 36 respectively whereby annulus 35 is located internally of annulus 36.

Annulus 35 has an internal bore 37 rotatably located on the external face of sleeve 33 and has an external cylindrical face 38, the axis of the internal bore 37 being spaced from the axis of its external cylindrical face 38. Annulus 36 has an internal bore 40 rotatably located of the external cylindrical face 38 and has an external cylindrical face 41 upon which a bore 42 of the gear 15 is rotatably received. The axis of bore 40 is co axial with the outer circumference of gear 15. The eccentricity of the eccentric assembly 30 relative to the axis of the drive shaft is defined by the external cylindrical face 41 and the degree of eccentricity of face 41 4 is chosen such that gear 15 meshes with the ring gear 16 at a given radial position. The eccentricity of the face 38 to bore 37 and of face 41 to bore 40 is chosen such that relative rotary movement of the annuli 35, 36 in a first direction causes the degree of eccentricity of face 41 to increase and that relative rotary movement of the annuli 35, 36 in a second opposite direction causes the degree of eccentricity of face 41 to decrease.

In the embodiment illustrated in Figure 1, relative movement in the first direction (ie. to increase eccentricity of face 41) is achieved by annulus 35 moving in an anti-clockwise direction and annulus 36 moving in a clockwise direction; and relative movement in the second direction (ie to decrease eccentricity of face 41) is achieved by annulus 35 moving in a clockwise direction and annulus 36 moving in an anti-clockwise direction.

is Relative movement of the annuli in said first direction has the effect of moving the gear 15 radially outwardly toward the ring gear 16. Such movement is caused by biasing means 50, preferably in the form of a resilient T' shaped spring made for example from spring steel.

The strength of the bias created by the biasing means 50 is sufficient to cause gear 15 to be biased radially outwardly to contact the gear 16 and so eliminates any fi-ee play therebetween resulting from manufacturing tolerances and wear. In effect, the annuli 35, 36 wedge the gear 15 radially outwardly against gear 16 and such an arrangement provides a solid connection between the gears 15, 16 and the drive shaft and thereby provides high collapse resistance to impact loadings.

In order to move the gear 15 radially inwardly to enable angular adjustment to be made between arms 12, 14 drive means 60 are provided connected to the drive shaft 25. Preferably the drive means 60 includes a drive peg 62 mounted on a radial arm 63 provided on the shaft 25. The peg 62 projects axially into a window 64 formed by opposed recesses 65, 66 formed in the annuli 35, 36 respectively; each recess 65, 66 including a pair of opposed radially directed walls 68, 69 respectively which act as abutment shoulders against which the peg 62 may abut.

The recesses 65, 66 are formed such that the opposed pair of walls 68 are radially offset from the pair of walls 69 when the annuli 35, 36 are 10 located at their biased positions as seen in Figure 1.

Accordingly, radial wall 68 of recess 65 located on the clockwise side of peg 62 is located in-board (in the anti-clockwise direction) of the adjacent radial wall 69 of recess 66 -such that clockwise movement of shaft 25 causes M 62 to abut against wall 68 first and initially move the annulus 35 in a clockwise direction relative to annulus 36. Such movement causes the eccentricity of face 41 to decrease and thereby cause gear 15 to be moved radially inwardly.

Continued rotation of shaft 25 in the clockwise direction causes annulus 36 to rotate in the clockwise direction in unison with annulus 35 due to transmission of driving force via the biasing means 50. Such movement of the annuli 35, 36 causes the gear 15 to progress in a clockwise direction around the gear 16 and thereby cause angular adjustment between arms 12, 14.

Release of the drive shaft 25 enables the biasing means to return the annuli 35, 36 to their biased portions.

Similarly, the radial wall 69 of recess 66 on the anti-clockwise side 6 of peg 62 is located in-board (in a clockwise direction) of adjacent wall 68 of recess 65 such that anti-clockwise movement of shaft 25 causes peg 62 to first engage wall 69 and thereby rotate annulus 36 in an anticlockwise direction relative to annulus 35. Such movement causes the eccentricity 5 of face 41 to decrease and thereby move gear 15 radially inwardly.

Continued anti-clockwise rotation of shaft 25 causes both annuli 35, 36 rotate in unison in the anti-clockwise direction. Again release of the shaft 25 enables the biasing means to return the annuli to their biased positions.

The combination of annuli 35, 36 enables a relatively low torque load to be applied for initiating release of the annuli and adjustment of the mechanism. In addition, since the bearing faces between the drive shaft, annuli 35, 36 and first gear tend to remain in sliding contact due to the influence of the biasing means 50, a smooth feel is provided during adjustment. In addition, any ovality in the bearing surfaces is accommodated by the biasing means 50 during adjustment such that the feel in adjustment is not materially affected.

7

Claims

1. A hinge assembly including a first hinge part hingedly connected to a second hinge part via a drive transmission assembly for angular movement about a hinge axis, the drive transmission assembly including a first hinge gear fixedly mounted on the first part, the first hinge gear being located within a ring gear fixedly mounted on the second hinge part, the first gear being eccentrically mounted on a drive shaft which is rotatably received in the second part for rotation about an axis co-axial with the ring gear characterised in that the first gear is eccentrically mounted on the drive shaft by an eccentric cam assembly comprising at least two concentrically arranged eccentric annuli rotatably mounted on the drive shaft, the annuli being biased for rotation in opposite directions and arranged such that relative rotation movement in said opposite directions causes an increase in the eccentricity of the first gear relative to the drive shaft, and so causes the first gear to move radially outwardly toward said ring gear, the drive shaft including drive means which on rotation of the drive shaft in a given direction initially causes one of the annuli to move in that given direction in order to move said one annuli against the bias and causes a decrease in the eccentricity of the first gear relative to the drive shaft and so causes the first gear to move radially inwardly away from said ring gears.

2. A hinge assembly according to Claim 1 wherein two concentrically arranged eccentric annuli are provided, one of said annuli defining an inner annulus located closer to the drive shaft and the other of said annuli defining an outer annulus, the inner annulus having an outer cylindrical face.

3.A hinge assembly according to Claim 1 wherein the eccentric cam 8 assembly comprises two concentrically arranged eccentric annuli which define an inner annulus and an outer annulus, the inner annulus being rotatably mounted for rotation about the axis of the drive.shaft and having an outer peripheral surface which is eccentrically arranged relative to said axis, the outer annulus having an inner peripheral surface rotatably received on the outer peripheral surface of the inner annulus, said inner peripheral surface of the outer annulus and the outer peripheral surface of the inner annulus each having a recess which are opposed to one another to define a window, the drive means including a drive member located within said window which on rotation of the drive shaft initially causes relative rotation between said inner and outer annuli for decreasing the eccentricity of said first gear.

3. A hinge assembly according to Claim 2 wherein each recess has a pair of opposed radially directed walls spaced circumferentially from one another which act as abutment shoulders against which the drive member may abut on rotation of the drive shaft, the radially directed walls of the inner annulus being offset from the radially directed walls of the outer annulus when the annuli are located at their biased positions.

4. A hinge assembly according to Claim 2 or 3 wherein said biasing means comprises a T' shaped spring.

5. A hinge assembly according to Claim 2, 3 or 4 wherein the inner annulus is rotatably received upon a sleeve formed on the second hinge part, the sleeve rotatably supporting said drive shaft.

6. A hinge assembly according to any preceding claim wherein the first hinge parts comprise an arm integrally formed with the first gear.

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7. A hinee assembly according to any preceding claim wherein the second hinge part comprises an arm integrally formed with the second gear.

8. A hinge assembly according to any preceding claim wherein the -first and second parts are formed from metal sheet by a pressing operation.

9. A seat reclining mechanism for a vehicle seat including a hinge 10 assembly according to any preceding claim.

10. A vehicle seat including a seat reclining mechanism according to Claim 9.