Drive belt

Abstract

A drive belt includes at least one continuous band and a number of cross elements having a transversely curved saddle surface of saddle radius for interacting with an inwardly oriented main face of the continuous band that at a first lateral side thereof adjacent a pillar part of the element connects to a concavely recessed surface part through a first convexely curved transition surface part. The drive belt features include that: a transverse width of the continuous band is larger than that of the saddle surface; the saddle radius is essentially constant throughout the transverse width of the saddle surface; the saddle radius is smaller than a band radius of a transverse curvature of the band in an unloaded state thereof, irrespective of an amount of bending in the longitudinal direction of the band; and the first transition surface part forms a relatively sharp edge.

1 . Drive belt ( 1 ) to be incorporated between the sheaves of a pair of pulleys ( 4 ,  5 ) of a transmission for realising a continuously adjustable transmission ratio, the belt ( 1 ) comprising at least one continuous band ( 21 ) and a number of cross elements ( 30 ) arranged in association with the continuous band ( 21 ) freely movable in a longitudinal direction thereof, each cross element ( 30 ) having a contact face or saddle surface ( 31 ) for interacting with an inwardly oriented main face of the continuous band ( 21 ), whereby a transverse width (W) of the continuous band ( 21 ) is larger than a transverse width of the saddle surface ( 31 ), which saddle surface ( 31 ) is provided with a transverse convex curvature of saddle radius (Rs) and which saddle surface ( 31 ) at a first lateral side adjacent a pillar part ( 33 ) of the element ( 30 ) connects to a concavely recessed surface part ( 34 ) through a first convexely curved transition surface part ( 35 ), characterised in that the following features are combined in the drive belt ( 1 ): 
 the saddle radius (Rs) is essentially constant throughout the axial, i.e. transverse width of the saddle surface ( 31 );    the first transition surface part ( 35 ) is defined inside an imaginary arc-shaped curvature having a radius of 5 mm thus forming a relatively sharp edge; and    the saddle radius (Rs) is designed to be smaller than a so-called band radius (Rb) of a transverse curvature of the band ( 21 ) in an unloaded state thereof, irrespective of an amount of bending in the longitudinal direction of the band ( 21 ) between the sheaves of a pulley  4 ,  5  that may occur during operation in the transmission.    
   
   
       2 . Drive belt ( 1 ) according to  claim 1 , characterised in that the first transition surface part ( 35 ) is shaped as a convex curvature having a radius of curvature (Rc 1 ) that amounts to about 1% or less of the saddle radius (Rs).  
   
   
       3 . Drive belt ( 1 ) according to  claim 1 , characterised in that the saddle radius (Rs) has a value of about 250 to 300 mm.  
   
   
       4 . Drive belt ( 1 ) according to  claim 1 , characterised in that the cross element ( 30 ) is formed form sheet material by a blanking operation. and that the first transition surface part ( 35 ) is shaped as a convex curvature having a radius of curvature (Rc 1 ) of about 3 mm.  
   
   
       5 . Drive belt ( 1 ) according to  claim 1 , characterised the respective other lateral side of the saddle surface ( 31 ) connects to a predominantly transversely oriented side face ( 32 ) of the cross element ( 30 ) through a second convexely curved transition surface part ( 36 ) that forms a relatively sharp edge, preferably being shaped as a convex curvature having a radius of curvature (Rc 2 ) of about 3 mm.  
   
   
       6 . Drive belt ( 1 ) according to  claim 1 , characterised in that a transverse position (C 1 ) of a highest point on the saddle surface ( 31 ) as seen in radial direction is located eccentric with respect transverse width of the saddle surface ( 31 ) away from the said first transition surface part ( 35 ) and towards the said second transition surface part ( 36 ).  
   
   
       7 . Drive belt ( 1 ) according to  claim 1 , characterised in that the transverse width (W) of the continuous band ( 21 ) is less than 1.25 times the transverse width of the saddle surface ( 31 ), preferably less than 1.15 times the latter width.  
   
   
       8 . Drive belt ( 1 ) according to  claim 2 , characterised in that the saddle radius (Rs) has a value of about 250 to 300 mm.  
   
   
       9 . Drive belt ( 1 ) according to  claim 2 , characterised in that the cross element ( 30 ) is formed form sheet material by a blanking operation and that the first transition surface part ( 35 ) is shaped as a convex curvature having a radius of curvature (Rc 1 ) of about 3 mm.  
   
   
       10 . Drive belt ( 1 ) according to  claim 3 , characterised in that the cross element ( 30 ) is formed form sheet material by a blanking operation. and that the first transition surface part ( 35 ) is shaped as a convex curvature having a radius of curvature (Rc 1 ) of about 3 mm.  
   
   
       11 . Drive belt ( 1 ) according to  claim 2 , characterised the respective other lateral side of the saddle surface ( 31 ) connects to a predominantly transversely oriented side face ( 32 ) of the cross element ( 30 ) through a second convexely curved transition surface part ( 36 ) that forms a relatively sharp edge, preferably being shaped as a convex curvature having a radius of curvature (Rc 2 ) of about 3 mm.  
   
   
       12 . Drive belt ( 1 ) according to  claim 3 , characterised the respective other lateral side of the saddle surface ( 31 ) connects to a predominantly transversely oriented side face ( 32 ) of the cross element ( 30 ) through a second convexely curved transition surface part ( 36 ) that forms a relatively sharp edge, preferably being shaped as a convex curvature having a radius of curvature (Rc 2 ) of about 3 mm.  
   
   
       13 . Drive belt ( 1 ) according to  claim 4 , characterised the respective other lateral side of the saddle surface ( 31 ) connects to a predominantly transversely oriented side face ( 32 ) of the cross element ( 30 ) through a second convexely curved transition surface part ( 36 ) that forms a relatively sharp edge, preferably being shaped as a convex curvature having a radius of curvature (Rc 2 ) of about 3 mm.  
   
   
       14 . Drive belt ( 1 ) according to claim]  2 , characterised in that a transverse position (C 1 ) of a highest point on the saddle surface ( 31 ) as seen in radial direction is located eccentric with respect transverse width of the saddle surface ( 31 ) away from the said first transition surface part ( 35 ) and towards the said second transition surface part ( 36 ).  
   
   
       15 . Drive belt ( 1 ) according to claim]  3 , characterised in that a transverse position (C 1 ) of a highest point on the saddle surface ( 31 ) as seen in radial direction is located eccentric with respect transverse width of the saddle surface ( 31 ) away from the said first transition surface part ( 35 ) and towards the said second transition surface part ( 36 ).  
   
   
       16 . Drive belt ( 1 ) according to claim]  4 , characterised in that a transverse position (C 1 ) of a highest point on the saddle surface ( 31 ) as seen in radial direction is located eccentric with respect transverse width of the saddle surface ( 31 ) away from the said first transition surface part ( 35 ) and towards the said second transition surface part ( 36 ).  
   
   
       17 . Drive belt ( 1 ) according to claim]  5 , characterised in that a transverse position (C 1 ) of a highest point on the saddle surface ( 31 ) as seen in radial direction is located eccentric with respect transverse width of the saddle surface ( 31 ) away from the said first transition surface part ( 35 ) and towards the said second transition surface part ( 36 ).  
   
   
       18 . Drive belt ( 1 ) according to  claim 2 , characterised in that the transverse width (W) of the continuous band ( 21 ) is less than 1.25 times the transverse width of the saddle surface ( 31 ), preferably less than 1.15 times the latter width.  
   
   
       19 . Drive belt ( 1 ) according to  claim 3 , characterised in that the transverse width (W) of the continuous band ( 21 ) is less than 1.25 times the transverse width of the saddle surface ( 31 ), preferably less than 1.15 times the latter width.  
   
   
       20 . Drive belt ( 1 ) according to  claim 4 , characterised in that the transverse width (W) of the continuous band ( 21 ) is less than 1.25 times the transverse width of the saddle surface ( 31 ), preferably less than 1.15 times the latter width.