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US-12624744-B2 - Raw edge cogged V-belt, method for using same, and belt transmission mechanism

US12624744B2US 12624744 B2US12624744 B2US 12624744B2US-12624744-B2

Abstract

The present invention relates to a raw edge cogged V-belt, including: a cog at least on an inner circumferential surface side; and a compression rubber layer disposed on the inner circumferential surface side, in which the compression rubber layer includes a compression rubber layer main body and an inner surface layer covering an inner circumferential surface of the compression rubber layer main body, and a friction coefficient of a surface of the inner surface layer is higher than a friction coefficient of a surface of the compression rubber layer main body that is not covered with the inner surface layer.

Inventors

  • Hidetaka Nakajima
  • Keiji Takano

Assignees

  • MITSUBOSHI BELTING LTD.

Dates

Publication Date
20260512
Application Date
20230515
Priority Date
20220516

Claims (6)

  1. 1 . A raw edge cogged V-belt, comprising: a cog at least on an inner circumferential surface side; and a compression rubber layer disposed on the inner circumferential surface side, wherein the compression rubber layer comprises a compression rubber layer main body and an inner surface layer covering an inner circumferential surface of the compression rubber layer main body, a friction coefficient of a surface of the inner surface layer is higher than a friction coefficient of a surface of the compression rubber layer main body that is not covered with the inner surface layer, and an average thickness of the inner surface layer is 0.3 mm to 2 mm.
  2. 2 . The raw edge cogged V-belt according to claim 1 , wherein the friction coefficient of the surface of the inner surface layer is 0.4 to 0.7.
  3. 3 . The raw edge cogged V-belt according to claim 1 , wherein a rubber hardness Hs (type A) of the inner surface layer is 82° or less, and a rubber hardness Hs (type A) of the compression rubber layer main body is 89° or more.
  4. 4 . A belt power-transmission system, comprising: the raw edge cogged V-belt according to claim 1 ; and a pulley, wherein the raw edge cogged V-belt is a variable speed belt used in a belt clutch-in type continuously variable transmission.
  5. 5 . The belt power-transmission system according to claim 4 , wherein the belt clutch-in type continuously variable transmission is a continuously variable transmission in which a belt inner circumferential surface comes into contact with a pulley shaft portion during idling.
  6. 6 . The belt power-transmission system according to claim 4 , wherein the belt clutch-in type continuously variable transmission is a continuously variable transmission that utilizes a frictional force between a belt inner circumferential surface and a pulley shaft portion.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This is a U.S. National Phase Application under 35 U.S.C. § 371 of International Application No. PCT/JP2023/018187, filed May 15, 2023, which claims priority to Japanese Application Nos. 2022-080410, filed May 16, 2022, and 2023-073007, filed Apr. 27, 2023, which were published Under PCT Article 21 (2), the entire contents of which are incorporated herein by reference. TECHNICAL FIELD The present invention relates to a raw edge cogged V-belt for use in a belt-type continuously variable transmission, a method for using the same, and a belt power-transmission system. BACKGROUND ART A V-belt for transmitting power by frictional power-transmission includes a raw edge type (raw edge V-belt) that is a rubber layer in which a frictional power-transmission surface (V-shaped side surface) is exposed, and a wrapped type (wrapped V-belt) in which a frictional power-transmission surface is covered with a cover fabric, and is selectively used according to use depending on a difference in surface properties (friction coefficient between the rubber layer and the cover fabric) of the frictional power-transmission surface. Examples of the raw edge type V-belt include a raw edge V-belt in which cogs are not provided, a raw edge cogged V-belt in which cogs are provided only on a lower surface (inner circumferential surface) of the belt to improve bendability, and a raw edge cogged V-belt (raw edge double cogged V-belt) in which cogs are provided on both a lower surface (inner circumferential surface) and an upper surface (outer circumferential surface) of the belt to improve bendability. The raw edge V-belt and the raw edge cogged V-belt are mainly used for driving a general industrial machine and an agricultural machine, for driving accessories in an engine of an automobile, and the like. As other uses, there is a raw edge cogged V-belt, called a variable speed belt which is used in a belt-type continuously variable transmission (CVT) for a motorcycle (scooter), a snowmobile (small snowcat), an all-terrain vehicle (ATV), and the like. As illustrated in FIG. 1, a belt-type CVT 20 is a system that continuously changes a gear ratio by winding a V-belt 23 around a driving pulley 21 and a driven pulley 22. The pulleys 21 and 22 respectively include fixed sheaves 21a and 22a which are fixed or restricted from moving in an axial direction, and movable sheaves 21b and 22b which are movable in the axial direction, and inner circumferential walls of the fixed sheaves 21a and 22a and inner circumferential walls of the movable sheaves 21b and 22b form inclined opposing surfaces of a V-shaped groove. The pulleys 21 and 22 respectively have a structure in which widths of the V-shaped groove of the pulleys 21 and 22 formed by these fixed sheaves 21a and 22a and movable sheaves 21b and 22b can be continuously changed. Both end surfaces in a width direction of the V-belt 23 are formed as tapered surfaces having an inclination corresponding to the inclined opposing surfaces of the V-shaped groove of the respective pulleys 21 and 22, and are engaged with any position in an up-down direction on the opposing surfaces of the V-shaped grooves according to the changed widths of the V-shaped grooves. For example, when a state illustrated in (a) of FIG. 1 is changed to a state illustrated in (b) of FIG. 1 by decreasing the width of the V-shaped groove of the driving pulley 21 and increasing the width of the V-shaped groove of the driven pulley 22, the raw edge cogged V-belt 23 moves upward in the V-shaped groove on a driving pulley 21 side and moves downward in the V-shaped groove on a driven pulley 22 side, and a radius of winding across the respective pulleys 21 and 22 changes continuously, making it possible to continuously change the gear ratio. For example, a CVT for a motorcycle includes a driving pulley fixed around a crankshaft of an engine, a driven pulley connected to a driving shaft of a rear wheel via a gear or the like, and a V-belt wound around the driving pulley and the driven pulley. At a low speed, a movable sheave of the driving pulley moves away from a fixed sheave, the radius of winding across the driving pulley becomes smaller, and a movable sheave of the driven pulley moves closer to a fixed sheave, and the radius of winding across the driven pulley becomes larger. Therefore, the rear wheel is driven with a large torque at a low speed. On the other hand, at a high speed, the movable sheave of the driving pulley moves closer to the fixed sheave, the radius of winding across the driving pulley becomes larger, and the movable sheave of the driven pulley moves away from the fixed sheave, and the radius of winding across the driven pulley becomes smaller. Therefore, the rear wheel is driven with a small torque at a high speed. On the other hand, there is a difference between a motorcycle and a snowmobile or an all-terrain vehicle in a clutch system (system that temporarily interrupts transmissi