Abstract: A metal V-belt includes a plurality of metal elements supported by a metal ring. The metal ring includes front and rear main surfaces, a pair of left and right slots that receive the metal ring therein, the slots being defined between a saddle surface and an ear-part bottom surface. A protrusion is provided on one of the front and rear main surfaces, and a concavity is provided in the other of the front and rear main surfaces. A clearance defined between an outermost peripheral surface of the metal ring and the ear-part bottom surface of the metal element is set to a value that at an exit of a driven pulley, contact of the innermost peripheral surface of the metal ring with the saddle surface of the metal element, and contact of the protrusion of a succeeding metal element and the concavity of a preceding metal element is avoided.

Abstract: A belt (metal V belt) has a number of elements held by a ring in an endless shape and aligned in a peripheral direction of the ring. The element includes a head portion, a neck portion and a body portion. The body portion has a V face brought into contact with a drive pulley and a driven pulley and left and right locking edge portions wrapped with the ring and disposed on an inner peripheral side of the ring. The head portion is disposed on an outer peripheral side of the ring and having an ear portion extended to left and to right sides to be opposed to the locking edge portion. The neck portion integrally connects the body portion and the head portion. Front faces of the ear portion, the neck portion and the locking edge portion of the element are formed with contact portions capable of bringing the contiguous elements into contact with each other.

Abstract: In a continuously variable transmission metal belt, a lateral-most projecting portion of a side edge of a metal ring assembly wherein each metal ring is located between a radially central plane and a radially inner peripheral surface of the metal ring. A contact point in which the projecting portion abuts against a V-face of a pulley is closer to the radially central plane than to the radially inner peripheral surface. Moreover, as the metal rings are laminated on one another, recesses are formed between the side edges of the adjacent metal rings to retain oil therein, which lubricates the sliding faces of adjacent metal rings and enhances durability of the assembly.

Abstract: A belt type non-stage transmission is constituted so that a V belt obtained by connecting a plurality of elements using a belt is wound around a pair of pulleys which have a groove with V-shaped cross section and which groove width can be changed. A diffusion layer where at least one of Zn and Sn diffuses on a surface layer of a metallic material of the pulleys and the elements is provided to at least one of contacting surfaces between the pulleys and the elements. The diffusion layer contains S and P. As a result, high frictional coefficient and wear resistance can be maintained for a long time, so that the device can cope with heightening of output.

Abstract: A metal V-belt includes a plurality of metal elements supported by a metal ring. The metal ring includes front and rear main surfaces, a pair of left and right slots that receive the metal ring therein, the slots being defined between a saddle surface and an ear-part bottom surface. A protrusion is provided on one of the front and rear main surfaces, and a concavity is provided in the other of the front and rear main surfaces. A clearance defined between an outermost peripheral surface of the metal ring and the ear-part bottom surface of the metal element is set to a value that at an exit of a driven pulley, contact of the innermost peripheral surface of the metal ring with the saddle surface of the metal element, and contact of the protrusion of a succeeding metal element and the concavity of a preceding metal element is avoided.

Abstract: Although a radial outside portion of a metal ring contact surface of a neck section of a metal element which is contactably opposed to a side edge of a metal ring of a metal ring assembly has high frequencies of contacting with a side edge of the metal ring, it is possible to suppress abrasion of the side edge of the metal ring and to improve durability of the metal ring by setting a surface hardness of the radial outside portion lower than a surface hardness of the metal ring. In addition, by setting a surface hardness of the metal ring contact surface at its portion of the radial outside lower than the surface hardness of the metal ring contact surface at other portions thereof where the frequencies of contacting with the side edge of the metal ring becomes low, in comparison with a case of setting the surface hardness of the whole metal ring contact surface low, it is possible to increase strength of the metal element and to improve the durability of the metal element.

Abstract: A metal belt includes a metal ring assembly formed from a plurality of layered endless metal rings, and a large number of metal elements supported on the metal ring assembly, the metal belt assembly being wound around a pulley and transmitting a driving force. The clearance between adjacent metal rings is set to be in a range from negative to positive from the innermost ring to a middle ring and to be only positive from the middle ring to the outermost ring. Therefore, good lubricating conditions can be maintained by virtue of the clearance being always positive for sliding surfaces of the metal rings from the middle ring to the outermost ring, for which lubrication easily becomes insufficient in the prior art.

Abstract: A circumferential length correcting method for a metal ring including: a circumferential length measuring step of passing the metal ring around a driving roller and a driven roller, displacing the driving roller and the driven roller away from each other, and measuring the actual circumferential length of the ring under tension; and a circumferential length correcting step of correcting the circumferential length of the ring by displacing a circumferential length correcting roller by a predetermined distance in a direction in which the metal ring is extended. The method is capable of imparting an appropriate arc shape to the metal ring while correcting the circumferential length to fall within an appropriate value range.

Abstract: In a metal ring for a metal belt of a belt type continuously variable transmission, a relationship is established between a compressive residual stress of a metal ring of an innermost layer imparted by a nitriding treatment and a free state radius of the metal ring nondimensionalized by a minimum winding radius. In the relationship, the sum of a compressive residual stress acting on the inner peripheral face of the metal ring, a compressive stress due to flexure and a contact stress does not exceed the elastic deformation limit of the metal ring. The maximum compressive stress of the metal ring does not become excessive, and an abrasion resistance of the surfaces of the metal ring is guaranteed.

Abstract: A belt for a continuously variable transmission comprises endless plate-like rings 2 and a plurality of plate-like elements 3, which are placed adjacent to one another and slidably on the rings 2, so that the rings 2 are disposed on the saddle portions 34 of the elements 3, respectively. In each element 3, a first recess 42 is provided at the upper innermost part of each saddle portion 34 such that the first recess 42 is continuous to a corresponding lower side end of the neck portion 33. In addition, a second recess 43 is provided at the lower innermost part of each ear portion 35 such that the second recess 43 is continuous to a corresponding upper side end of the neck portion 33. At least one of the first and second recesses 42 and 43 is in an elliptic arc figure, in a compound arc figure that comprises various circular arcs or in a compound arc figure that comprises an elliptic arc and one or more circular arcs.

Abstract: The invention provides a circumferential length correcting method for a metal ring including: a circumferential length measuring step of passing the metal ring around a driving roller and a driven roller, displacing the driving roller and the driven roller away from each other, and measuring the actual circumferential length of the ring under tension; and a circumferential length correcting step of correcting the circumferential length of the ring by displacing a circumferential length correcting roller by a predetermined distance in a direction in which the metal ring is extended, the method being capable of imparting an appropriate arc shape to the metal ring while correcting the circumferential length to fall within an appropriate value range, and a circumferential length correcting apparatus therefor.

Abstract: A metal belt includes a metal ring assembly formed from a plurality of layered endless metal rings, and a large number of metal elements supported on the metal ring assembly, the metal belt assembly being wound around a pulley and transmitting a driving force. The clearance between adjacent metal rings is set to be in a range from negative to positive from the innermost ring to a middle ring and to be only positive from the middle ring to the outermost ring. Therefore, good lubricating conditions can be maintained by virtue of the clearance being always positive for sliding surfaces of the metal rings from the middle ring to the outermost ring, for which lubrication easily becomes insufficient in the prior art.

Abstract: A belt (metal V belt) has a number of elements held by a ring in an endless shape and aligned in a peripheral direction of the ring. The element includes a head portion, a neck portion and a body portion. The body portion has a V face brought into contact with a drive pulley and a driven pulley and left and right locking edge portions wrapped with the ring and disposed on an inner peripheral side of the ring. The head portion is disposed on an outer peripheral side of the ring and having an ear portion extended to left and to right sides to be opposed to the locking edge portion. The neck portion integrally connects the body portion and the head portion. Front faces of the ear portion, the neck portion and the locking edge portion of the element are formed with contact portions capable of bringing the contiguous elements into contact with each other.

Abstract: Protrusions formed on an inner peripheral surface of at least an innermost metal ring of a belt for a continuously variable transmission are initially worn. An average contact width w of the protrusions, measured in a direction perpendicular to a direction of travel of the metal ring, is equal to or less than 16 ?m. The development of pitching at a top of the protrusion in a depthwise direction is inhibited. Shallow pitching is eliminated due to the contact between the protrusion and a metal element, which prevents the generation of cracks. When the metal ring and the metal element are conformed to each other, the average Hertz's surface pressure is lowered, whereby the pitching is difficult to occur. Also, the top of the protrusion is worn, leading to an improved surface roughness, whereby the lubrication is enhanced, resulting in an enhancement of metal ring durability.

Abstract: In a continuously variable transmission metal belt, a lateral-most projecting portion of a side edge of a metal ring assembly wherein each metal ring is located between a radially central plane and a radially inner peripheral surface of the metal ring. A contact point in which the projecting portion abuts against a V-face of a pulley is closer to the radially central plane than to the radially inner peripheral surface. Moreover, as the metal rings are laminated on one another, recesses are formed between the side edges of the adjacent metal rings to retain oil therein, which lubricates the sliding faces of adjacent metal rings and enhances durability of the assembly.

Abstract: A belt for a continuously variable transmission comprises endless plate-like rings 2 and a plurality of plate-like elements 3, which are placed adjacent to one another and slidably on the rings 2, so that the rings 2 are disposed on the saddle portions 34 of the elements 3, respectively. In each element 3, a first recess 42 is provided at the upper innermost part of each saddle portion 34 such that the first recess 42 is continuous to a corresponding lower side end of the neck portion 33. In addition, a second recess 43 is provided at the lower innermost part of each ear portion 35 such that the second recess 43 is continuous to a corresponding upper side end of the neck portion 33. At least one of the first and second recesses 42 and 43 is in an elliptic arc figure, in a compound arc figure that comprises various circular arcs or in a compound arc figure that comprises an elliptic arc and one or more circular arcs.

Abstract: Protrusions formed on an inner peripheral surface of at least an innermost metal ring of a belt for a continuously variable transmission are initially worn. An average contact width w of the protrusions, measured in a direction perpendicular to a direction of travel of the metal ring, is equal to or less than 16 &mgr;m. The development of pitching at a top of the protrusion in a depthwise direction is inhibited. Shallow pitching is eliminated due to the contact between the protrusion and a metal element, which prevents the generation of cracks. When the metal ring and the metal element are conformed to each other, the average Hertz's surface pressure is lowered, whereby the pitching is difficult to occur. Also, the top of the protrusion is worn, leading to an improved surface roughness, whereby the lubrication is enhanced, resulting in an enhancement of metal ring durability.

Abstract: In a belt for a continuously variable transmission, the relationship of &thgr;NH<&thgr;Y is established between the following two angles: (i) an angle &thgr;Y formed between a straight line drawn from a lower end of one of left and right pulley-abutment faces of a metal element to an outer end of the other of the left and right lower ear surfaces and a straight line drawn from a point of the intersection of a straight line drawn downwards from the point with an outer peripheral surface of a metal ring assembly to the point; and (ii) an angle &thgr;NH formed between a tangent line drawn from the point onto a projection and a tangent line drawn from the point onto a recess of the metal element.

Abstract: In a belt for a continuously variable transmission, the relationship of &thgr;NH<&thgr;Y is established between the following two angles: (i) an angle &thgr;Y formed between a straight line drawn from a lower end of one of left and right pulley-abutment faces of a metal element to an outer end of the other of the left and right lower ear surfaces and a straight line drawn from a point of the intersection of a straight line drawn downwards from the point with an outer peripheral surface of a metal ring assembly to the point; and (ii) an angle &thgr;NH formed between a tangent line drawn from the point onto a projection and a tangent line drawn from the point onto a recess of the metal element.

Abstract: In a belt for a continuously variable transmission including a large number of metal elements carried on metal ring assemblies each of which is comprised of a plurality of endless metal rings laminated one on another, the amplitude &sgr;a1 of a total stress on the inner circumferential surface of the innermost metal ring is larger than the amplitude &sgr;an of a total stress on the inner circumferential surfaces of the other metal rings, and a maximum value of a tensile stress on the inner circumferential surface of the innermost metal ring is larger than a maximum value of a tensile stress on the inner circumferential surfaces of the other metal rings. Therefore, a compressive residual stress is applied to the inner circumferential surface of the innermost metal ring used under the severest condition, and the middle value &sgr;m1 of the amplitude &sgr;a1 of the stress on the innermost metal ring is brought close or equal to 0.