Abstract: In a high load transmission V-belt, a plurality of blocks 20 are attached and fixed to a tension band 10 extending in a belt length direction in a state in which each of the blocks 20 are arranged so as to sandwich an engagement section 18 of the tension band 10 in an inter-beam clearance portion 26 formed between upper and lower beam portions 23, 24. An increased amount of change ?T in dimension T of the engagement section 18 of the tension band 10 in a belt thickness direction due to thermal expansion is equal to or less than an amount of change ?G in dimension G of the inter-beam clearance portion 26 of the block 20 in the belt thickness direction while running the belt (?T??G).

Abstract: The present invention aims at improving the shock resistance of a block without lowering the power transmission property or the wear resistance of a belt while suppressing the separation of the contact portion off of the reinforcing member. A high-load drive V-belt B includes: at least one tension band 10 extending in an endless loop; and a plurality of blocks 20 engaged and secured to the tension band 10 at a predetermined pitch in a belt length direction of the tension band 10, wherein the plurality of blocks 20 are each formed by a reinforcing member 27 and a resin on both sides of the reinforcing member 27 in a belt width direction, and each include a contact portion 28 having a contact surface 30 to be in contact with a pulley, and a thickness w of the contact portion 28 in a direction perpendicular to the contact surface 30 is set to 1.0 mm or more and 1.8 mm or less.

Abstract: A flat belt includes an adhesive rubber layer formed in an endless ring shape and having a tensile member embedded therein, a first rubber layer provided on a surface of the adhesive rubber layer, and a second rubber layer provided on the other surface of the adhesive rubber layer, in which an elastic modulus in a belt width direction of the adhesive rubber layer is higher than the elastic modulus in the belt width direction of each of the first rubber layer and the second rubber layer.

Abstract: In a high load transmission V-belt, a plurality of blocks 20 are attached and fixed to a tension band 10 extending in a belt length direction in a state in which each of the blocks 20 are arranged so as to sandwich an engagement section 18 of the tension band 10 in an inter-beam clearance portion 26 formed between upper and lower beam portions 23, 24. An increased amount of change ?T in dimension T of the engagement section 18 of the tension band 10 in a belt thickness direction due to thermal expansion is equal to or less than an amount of change ?G in dimension G of the inter-beam clearance portion 26 of the block 20 in the belt thickness direction while running the belt (?T??G).

Abstract: A belt drive system including an assembly of a heavy-duty drive V-belt 5 and pulleys 2 and 4 reduces noise generating owing to belt travel while ensuring the durability of the pulleys 2 and 4. The surfaces of belt grooves 6 in the V-pulleys 2 and 4 are micro-blasted or burnished so that their surface roughness satisfies the relational expression y??0.9×tp+100, where tp is the load length rate at a given position of a roughness curve indicating the surface features of the groove surfaces in the V-pulleys 2 and 4 and y is the variable (the degree of height) indicating by percentage the ratio of the height from the lowest valley having a maximum depth to the given position to a maximum height Ry.

Abstract: The present invention aims at improving the shock resistance of a block without lowering the power transmission property or the wear resistance of a belt while suppressing the separation of the contact portion off of the reinforcing member. A high-load drive V-belt B includes: at least one tension band 10 extending in an endless loop; and a plurality of blocks 20 engaged and secured to the tension band 10 at a predetermined pitch in a belt length direction of the tension band 10, wherein the plurality of blocks 20 are each formed by a reinforcing member 27 and a resin on both sides of the reinforcing member 27 in a belt width direction, and each include a contact portion 28 having a contact surface 30 to be in contact with a pulley, and a thickness w of the contact portion 28 in a direction perpendicular to the contact surface 30 is set to 1.0 mm or more and 1.8 mm or less.

Abstract: A belt drive system including an assembly of a heavy-duty drive V-belt 5 and pulleys 2 and 4 reduces noise generating owing to belt travel while ensuring the durability of the pulleys 2 and 4. The surfaces of belt grooves 6 in the V-pulleys 2 and 4 are micro-blasted or burnished so that their surface roughness satisfies the relational expression y??0.9×tp+100, where tp is the load length rate at a given position of a roughness curve indicating the surface features of the groove surfaces in the V-pulleys 2 and 4 and y is the variable (the degree of height) indicating by percentage the ratio of the height from the lowest valley having a maximum depth to the given position to a maximum height Ry.

Abstract: The power transmission ability of a belt for high power transmission is predicted. A power transmission ability curve of the belt that does not depend on the layout relative to the pulleys is found, thereby to facilitate evaluation of the belt power transmission ability and designing of the transmission condition of a belt drive system. To this end, for the high power transmission belt, a relational expression between the WD factor which is the pressing force against pulleys per belt unit length and the ST factor which is the effective tension of the belt per unit contact length to the pulleys is found. Based on the relational expression, evaluation of the power transmission ability of the belt is conducted. The WD-ST relational expression becomes a power transmission ability curve which is inherent to the belt B but independent of the layout relative to the pulleys, therefore facilitating evaluation of the belt power transmission ability and designing of the transmission condition of the belt drive system.

Abstract: A block-type heavy-duty power transmission V-belt including a large number of blocks fixedly engaged with tension members by fitting the tension members in fitting grooves formed on side faces of the blocks. In a reinforcing member embedded in each of the blocks, a beam angle between a vertical center line of an upper beam part disposed above the fitting groove and a pulley groove face closer to the center of a pulley than a portion of the pulley in contact with an upper contact part of the block is 90° or more. In this manner, to the base of the upper beam part is applied merely tensile stress derived from a shearing force working in a lengthwise direction of the belt between the block and the tension member, or tensile stress reduced correspondingly to compressive stress derived from downward bending moment applied to the upper beam part due to a reaction force from the pulley groove face.

Abstract: A heavy-duty power transmission V-belt includes right and left tension members having concave parts on upper and lower faces thereof, and a large number of blocks having fitting parts for compressedly fitting the tension members therein on right and left side faces of the blocks. By compressedly fitting the tension members in the fitting parts of the blocks, the respective blocks are fixedly engaged with the tension members so as to allow the side faces thereof to be brought into contact with a groove face of the pulley. An innermost lower face is formed in an innermost portion of the fitting part of each block, and an innermost lower face angle &agr; between the innermost lower face and a vertical plane is determined so as to have a relationship of &bgr;−3<&agr;<&bgr;+3 with a belt side face angle &bgr;.

Abstract: A heavy-duty power transmission V-belt is so designed that respective upward projections each having an arcuate cross section of respective blocks are fixedly engaged with respective bottom-surface grooves each having an arcuate cross section of a tension member. The radius of curvature R2 of each bottom-surface groove is set larger than the radius of curvature R1 of the upward projection of the block (R2>R1) in the state that the tension member is put strait. Thereby, when the V-belt bends around a pulley, it can be avoided that a large local strain occurs at the bottom-surface groove. This allows a firmly fixed state of each block by the tension member to be maintained for a long time.

Abstract: A roller for running a flat belt is formed at its surface by an elastic body. Short fibers are mixed with the elastic body. The short fibers are averagely oriented in a direction radially or peripherally inclined to the roller with a small angle and protrude at their tip portions from the roller surface. Owing to a grip force of the protruding short fibers, the flat belt is running, while decreasing a friction coefficient and obtaining a stability to a variation of temperature and humidity. The short fibers may be oriented in a direction axially, peripherally inclined thereto with a specific angle. When a belt guide member is provided to the roller or flat belt, accurate running of the belt is performed.

Abstract: A belt driving system having at least one roller for adjusting creep within a plurality of rollers. Creep detecting means provided at one end of the creep adjusting roller is rotated by torque of a flat belt in contact with the creep detecting means. Biasing means for biasing the flat belt toward the creep detecting means and roller-end displacing means for converting the torque of the creep detecting means to displacement of the end of the creep adjusting roller toward a predetermined direction so that the flat belt is moved to the direction contrary to the creep caused by the biasing means are provided. When the flat belt creeps, the creep contrary to the original creep is caused by the roller-end displacing means, and thus the original creep is compensated. Consequently, stable running of the flat belt is obtained and clear pictures of the electrophotographic machine can be also obtained.