JP2006097724A - V-ribbed belt and belt abnormal noise evaluation method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a V ribbed belt forming a rib on the lower face of a belt body and capable of securely reproducing an abnormal sound in a belt traveling test by paying an attention to the surface state of the rib. <P>SOLUTION: Short fibers 4b, 4b, etc. protruding from the side face of the rib 4a of the V ribbed belt B are cut to increase the coefficient of the friction μ' of the side face to be higher than 1.5. The cutting of the short fibers 4b, 4b, etc. is performed by so-called zero cutting by making the feed amount of a grinding wheel zero after forming the rib 4a by grinding. The surface state of the side face of the rib 4a may have a surface coarseness Ra of 6 μm or less. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a V-ribbed belt in which a rib portion is formed on a lower surface of a belt body, and particularly belongs to a technical field for evaluating abnormal noise during belt running.

  2. Description of the Related Art Conventionally, a belt-type accessory driving device (belt transmission device) that transmits engine rotation to an auxiliary device by a belt is known as a driving device for driving an auxiliary device of an automobile. In general, a V-ribbed belt is used from the viewpoint of life and the like. For example, as shown in FIG. 1, the V-ribbed belt has a plurality of strips arranged on the lower surface of the belt body 1 in which the core wires are embedded so as to be arranged at a predetermined pitch in the belt width direction. The rib portions 4, 4,... (Three in the case of FIG. 1) are formed.

In such a V-ribbed belt, for example, as disclosed in Patent Document 1, the rubber layer constituting the rib part contains short fibers, and a part of these short fibers protrudes from the rib part side surface. 2. Description of the Related Art There is known a belt that improves the durability of the belt and adjusts the frictional resistance between the belt and the pulley.
JP 2001-176668 A

  By the way, in general, the pulley of the belt transmission device is easily tilted due to the influence of the deviation at the time of setting, operating conditions, and the like. Therefore, when the tilt is large and the approach angle of the V-ribbed belt with respect to the pulley is large, the belt There is a possibility that sliding may occur between the side surface of the rib portion and the groove surface of the pulley contacting the side surface, thereby generating abnormal noise. For this reason, conventionally, a belt running test is carried out with the pulley tilted using a belt that has been run with a relatively high friction coefficient on the surface of the rib portion, and whether or not abnormal noise is generated is confirmed.

  However, when an abnormal noise of the belt is evaluated by the belt running test as described above, the abnormal noise is not always generated, and the abnormal noise may not be generated depending on the surface condition of the belt. It was difficult to accurately determine, and it was difficult to accurately reflect the result of the abnormal noise evaluation in the design of the V-ribbed belt.

  The present invention has been made in view of such points, and an object of the present invention is to focus on the surface state of the rib portion in the V-ribbed belt in which the rib portion is formed on the lower surface of the belt body. The purpose is to obtain a belt that reproduces abnormal noise more reliably in the test.

  In order to achieve the above object, in the solution means of the present invention, the protrusion of the short fiber from the rib portion of the V-ribbed belt is suppressed so that the surface of the rib portion becomes a predetermined surface state having a large frictional force.

  That is, the invention of claim 1 is directed to a V-ribbed belt in which a plurality of rib portions extending in the belt length direction are formed on the lower surface of the belt main body by grinding. And at least the rubber layer of the rib part contains short fibers so as to protrude from the surface thereof, and the surface of the rib part is polished so that the friction coefficient is larger than 1.5. Shall.

  With this configuration, the protrusion of short fibers from the surface of the rib portion is suppressed, and the friction coefficient of the surface is higher than the friction coefficient of the product state and the belt that has been run, so the belt with the pulley tilted In the running test, the frictional force between the belt and the pulley is increased, and abnormal noise can be generated more reliably. That is, as shown in an example in FIG. 5, when a belt that has already traveled (the friction coefficient is approximately 1.28 in the example in the figure) is used, even if the approach angle of the belt to the pulley is changed, almost noisy noise is generated. However, when the belt approach angle is increased by making the friction coefficient of the rib portion surface larger than 1.5 as described above, noise is surely generated.

  The invention of claim 2 is directed to a V-ribbed belt in which a plurality of rib portions extending in the belt length direction are formed on the lower surface of the belt main body by grinding. And at least the rubber layer of the rib part contains short fibers so as to protrude from the surface thereof, and the surface of the rib part is polished so that the surface roughness Ra is smaller than 6 μm. Shall.

  Thereby, the short fibers protruding from the rib part surface are cut, the rib part surface becomes a smooth surface having a surface roughness Ra of less than 6 μm, and the friction coefficient of the surface becomes high. Similarly, abnormal noise can be generated with good reproducibility in the belt running test with the pulley tilted.

  In the above-described configuration, it is preferable that the surface of the rib portion is polished a predetermined number of times or more with the feed amount of the grinding tool of the rib portion being substantially zero (invention of claim 3). In this way, the structure according to claim 1 and 2 is reliably realized at a low cost by performing so-called zero cut more than a predetermined number of times to zero the feed amount of the grinding tool to the belt side after the rib portion grinding. be able to. In addition, by using a grinding tool for grinding the rib portion, the surface of the rib portion is polished almost uniformly over the entire circumference, so that the friction coefficient of the rib portion surface can be increased over the entire circumference. This makes it possible to generate an abnormal noise during belt running more reliably. Here, the predetermined number of times means the number of zero cuts in which the surface of the rib portion becomes a surface state in which abnormal noise is generated with good reproducibility in the belt running test.

  According to a fourth aspect of the present invention, there is provided a V-ribbed belt in which a plurality of rib portions extending in the belt length direction are formed by grinding on the lower surface of the belt body, and the surface of the rib portion is in a predetermined surface state. As described above, it is assumed that polishing is performed a predetermined number of times or more with the feed amount of the grinding tool at the rib portion being substantially zero. Thus, the same effect as that attained by the 3rd aspect can be attained.

  In addition, as the above-described belt running test, specifically, for example, any one of the above-described V-ribbed belts is used, and the V-ribbed belt has a predetermined entry angle with respect to the V-ribbed pulley. In addition, the V-ribbed pulley may be rotated in a predetermined operation state to evaluate abnormal noise during belt running (invention of claim 5). Here, the predetermined entry angle is an angle within a range in which the V-ribbed belt does not fall off from the V-ribbed pulley, and the predetermined operation state means an operation state that reproduces an actual traveling state, for example. .

  As described above, according to the V-ribbed belt and the belt abnormal noise evaluation method according to the present invention, the short fibers protruding from the surface of the rib portion are cut, and the friction coefficient of the surface is made larger than 1.5 or the surface roughness. By making Ra smaller than 6 μm, abnormal noise can be generated more reliably in the belt running test with the pulley tilted. And after forming the said rib part by grinding, the rib part surface of the above structures can be reliably obtained at low cost by performing zero cut using the grinding tool used for the grinding.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

  FIG. 1 shows a V-ribbed belt B according to an embodiment of the present invention. The V-ribbed belt B is used in an accessory drive system (see FIG. 4 to be described later) for driving an accessory by an engine mounted on an automobile, for example. The belt body 1 and the upper surface (back surface) of the belt body 1 are used. The belt body 1 includes an adhesive rubber layer 2 having a substantially rectangular shape when viewed in cross section, and a lower surface side of the adhesive rubber layer 2, that is, the lower surface side of the adhesive rubber layer 2. It consists of a rib rubber layer 4 laminated on the lower surface (bottom surface, inner peripheral surface) side of the belt body 1.

  The back canvas layer 3 is affixed to the back of the belt body 1 (adhesive rubber layer 2) by applying a rubber paste obtained by dissolving rubber in a solvent to a woven fabric such as nylon or cotton, and the back of the belt is flat. It serves as one end of power transmission when the V-ribbed belt B is wound so as to come into contact with a small pulley (for example, a rear idler).

  On the other hand, the adhesive rubber layer 2 is made of a rubber composition such as ethylene propylene diene monomer (EPDM) having excellent heat resistance and weather resistance. The rubber layer 2 extends in the belt length direction and has a belt width. A core wire 5 wound in a spiral shape is embedded so as to be arranged at a predetermined pitch in the direction. The core wire 5 is constituted by twisting a plurality of single yarns made of polyvinyl alcohol (PVA) fibers or the like.

  The rib rubber layer 4 is made of a rubber composition containing EPDM as a main rubber, like the adhesive rubber layer 2. On the lower surface side of the rib rubber layer 4, a plurality of rib portions 4a, 4a,... (Three in this embodiment) each extending in the belt length direction are formed in a state of being arranged at a predetermined pitch in the belt width direction. Has been. Thereby, for example, when the V-ribbed belt B is wound around the pulley, each rib portion 4a of the rib rubber layer 4 comes into contact with the pulley, and the power is transmitted from the driving side to the driven side.

  The rib rubber layer 4 including the rib portions 4a contains short fibers 4b, 4b,... Oriented in the belt width direction. These short fibers 4b, 4b,... Are made of, for example, nylon, and when the rib portions 4a are formed by grinding, outward from the side surfaces (surfaces) of the rib portions 4a. It will be in the state of protruding.

  Here, the formation method of each rib part 4a will be described. Each rib part 4a is formed on the lower surface of the rib rubber layer 4 using a grinding wheel (grinding tool) provided with uneven parts corresponding to the shape thereof. Formed on the side. Specifically, the grinding wheel has irregularities corresponding to the shapes of the rib portions 4a, 4a,... (See FIG. 1) formed on the outer peripheral surface thereof in the circumferential direction, and the belt rotates while rotating at high speed. The rib rubber layer 4 is pressed against the rib rubber layer 4 of B and ground. Then, the lower surface of the rib rubber layer 4 is ground in an irregular shape by the grinding wheel, and the protruding portions become the rib portions 4a, 4a,. The V-ribbed belt B is also running relatively slowly, and the entire circumference of the belt B is ground by the grinding wheel.

  And after forming each said rib part 4a by a grinding process as mentioned above, the side of each said rib part 4a is made into a belt by performing what is called zero cut which makes the feed amount of a grinding stone substantially zero in a finishing stage. Since the polishing is performed over the entire circumference, the short fibers 4b, 4b,... Protruding from the side surfaces are cut, and the protruding amount is suppressed. As described above, when the protruding amount of the short fibers 4b, 4b,... Protruding from the side surfaces of the rib portions 4a is suppressed, the friction coefficient of the side surfaces is influenced by the rubber composition mainly constituting the rib rubber layer 4. The friction coefficient becomes larger than the state in which the protruding amount of the short fibers 4b, 4b,. Specifically, the short fibers 4b, 4b,... Are not cut (product state) and the friction coefficient is approximately 0.8 to 0.9, but the short fibers 4b, 4b,. In the state, as shown in FIG. 2, the friction coefficient gradually increases in accordance with the number N of zero cuts (the number of times the grinding wheel is rotated with respect to the side surface of each rib portion 4a).

  FIG. 2 shows the relationship between the number N of zero cuts (the number of zero cuts when the rotational speed of the grinding wheel is 300 m / min), the friction coefficient μ ′ of the side surface of each rib portion 4a, and the surface roughness Ra. Yes. From this figure, it can be seen that as the number of zero cuts N increases, the surface roughness Ra of the side surface of each rib portion 4a decreases while the friction coefficient μ 'increases. In the example of the figure, the friction coefficient μ ′ on the side surface of each rib portion 4a is larger than 1.3 when zero cutting is performed 15 times or more, and the friction coefficient μ ′ is larger than 1.5. It becomes large when zero cut is performed 20 times or more. And the surface roughness Ra of the side surface of each said rib part 4a at this time becomes smaller than 8 micrometers and 6 micrometers, respectively.

  Note that the friction coefficient μ ′ of the side surface of each rib portion 4a of the V-ribbed belt B is such that the weight 11 is suspended from one end side of the belt B wound around the pulley 10 as shown in FIG. The friction coefficient was calculated on the basis of the tension of the belt B of the belt B by the so-called pulley rotation method. The tension of the V-ribbed belt B was measured at an ambient temperature of 25 degrees.

  Specifically, the V-ribbed belt B is wound around the pulley 10 at an angle of about 90 ° so that a horizontal portion and a vertical portion are formed, and a load W = 1.75 kg is applied to the lower end of the vertical portion of the V-ribbed belt B. While the weight 11 was suspended, the front end side of the horizontal portion was fixed to a wall or the like via the load cell 12. The pulley 10 was rotated at a rotational speed of 42 rpm so that the tension of the horizontal portion of the V-ribbed belt B was increased.

  From the tension T2 measured by the load cell 12 and the tension T1 generated in the V-ribbed belt B by the weight 11, the friction coefficient μ ′ of the side surface of the rib portion 4a of the V-ribbed belt B is obtained by the following equation.

μ ′ = ln (T2 / T1) / (π / 2)
Further, the surface roughness Ra of the side surface of each rib portion 4a of the V-ribbed belt B was measured with a contact-type surface roughness meter (surfcom 120A manufactured by Tokyo Seimitsu Co., Ltd.) with a cutoff value of 0.80. The measurement was performed under conditions of a length of 8 mm and an ambient temperature of 25 degrees.

(Abnormal noise evaluation)
Next, the abnormal noise evaluation during the belt running of the V-ribbed belt B when the pulley is inclined will be described.

  The V-ribbed belt B has the same configuration as that described above (see FIG. 1), and three types of belts that differ only in the treatment applied to the side surface of each rib portion 4a were prepared. Specifically, a belt in which each rib portion 4a is zero-cut 20 times or more and the friction coefficient of the side surface is 1.55 as Example 1, and each rib portion 4a is zero-cut approximately 18 times as Example 2 and the side surface. A belt having a friction coefficient of 1.38 and a belt that has been run as a comparative example (the friction coefficient of the side surface of each rib portion 4a is 1.28) were prepared.

  Further, the running test of each V-ribbed belt B was performed in an actual engine accessory drive system layout as shown in FIG. Specifically, each V-ribbed belt B is wound around a crankshaft pulley 21, an auto tensioner tension pulley 22, an alternator pulley 23, a power steering pump pulley 24, and a water pump pulley 25. The back side of the belt B (the back canvas layer 3 side in FIG. 1) is wound around a back idler 26 disposed between the pulley 24 for water and the pulley 25 for water pump (V-ribbed pulley). As a result, each V-ribbed belt B transmits the torque of the crankshaft pulley 21 that is a drive pulley to each of the pulleys 23, 24, and 25 for driving auxiliary machinery that is a driven pulley. In the running test apparatus according to the present embodiment, the rear idler 26 can be rotated or tilted within a predetermined angle range by tilting the rotational axis of the rear idler 26.

  Then, the rear idler 26 is rotated clockwise or counterclockwise as viewed from above and below (the front side or the back side in the figure) so that the belt B enters the water pump pulley 25 at a predetermined angle. The crankshaft pulley 21 as a driving pulley was rotated at 600 to 800 rpm (idling state) and 600 to 3000 rpm (racing state) in the direction of the arrow in the figure. In FIG. 4 when the accessory drive system is viewed from the side, when the rear idler 26 is rotated to the front side, the V-ribbed belt B enters the water pump pulley 25 from the front side. When the rear idler 26 is rotated to the back side, the V-ribbed belt B enters the water pump pulley 25 from the back side.

  In this embodiment, the misalignment angle (rotation angle) of the back idler 26 is changed, that is, the belt entry angle of the V-ribbed belt B to the water pump pulley 25 is changed, and the V-ribbed belt is moved during belt running. Abnormal noise generated by friction between B and the pulley 25 was measured with a microphone or the like (not shown). The belt entry angle in FIG. 4 is a positive value when the belt B enters from the back side of the water pump pulley 25 toward the front side, and from the front side of the water pump pulley 25 to the back side. The case where the belt B entered was negative. Further, when the belt entry angle becomes ± 3 degrees or more, each rib portion 4a of the V-ribbed belt B comes off from a groove portion (not shown) provided on the pulley and falls off, so the belt enters within a smaller angle range. The angle was changed.

  FIG. 5 shows an abnormal sound measurement result. From this measurement result, it can be seen that as the belt approach angle increases, the abnormal noise generated tends to increase, and the tendency becomes more prominent as the friction coefficient μ ′ on the side surface of the rib portion 4a is higher. That is, in the case of a traveled belt having a relatively low friction coefficient μ ′ on the side surface of the rib portion 4a, the noise level hardly changes even if the belt entry angle is changed, but the friction coefficient μ on the side surface of the rib portion 4a. When 'is large (particularly when the friction coefficient μ' is larger than 1.5), it can be seen that when the belt approach angle increases, the noise level suddenly increases and abnormal noise is generated.

  In the present embodiment, the abnormal noise means a loud noise having a noise level exceeding about 85 dBA. As shown in FIG. 5, the friction coefficient μ ′ on the side surface of the rib portion 4a is 1. If it is larger than 3, a large noise of about 85 dBA or more can be reliably generated. Furthermore, if the friction coefficient μ ′ is larger than 1.5, a large abnormal noise can be generated more reliably.

  As described above, when the friction coefficient μ ′ of the side surface of each rib portion 4a of the V-ribbed belt B is set to be larger than 1.5, the belt entry angle to the pulley 25 is changed in the belt running test. Since the frictional force at the time of entering the belt increases, abnormal noise can be generated more reliably than when a belt that has already traveled is used. As described above, since there is a correlation as shown in FIG. 2 between the friction coefficient μ ′ and the surface roughness Ra, the surface roughness Ra of the side surface of the rib 4a of the V-ribbed belt B is smaller than 6 μm. Even if it becomes, the same effect can be acquired.

  Therefore, abnormal noise can be generated more reliably than in a running test using a belt that has already been run, and the abnormal noise evaluation of the belt can be more accurately reflected in the design of the belt.

  Moreover, by polishing the surface of each rib portion 4a using a grinding wheel for forming the rib portions 4a, 4a,... Of the V-ribbed belt B, the friction coefficient μ ′ of the surface is reliably increased at low cost. can do. Further, since the surface of each rib portion 4a is polished over the entire belt circumference by using the grinding wheel, the friction coefficient μ ′ of the surface can be made substantially uniform over the entire belt circumference. An abnormal noise during traveling can be generated more reliably.

  In the belt running test, the surface of the rib portion 4a of the V-ribbed belt B may be sprayed with water using a sprayer or the like, or the surface of the rib portion 4a may be degreased. By doing so, the friction coefficient μ ′ on the side surface of each rib portion 4a of the belt B is further increased, so that abnormal noise can be generated more reliably.

It is a cross-sectional perspective view of the V-ribbed belt which concerns on embodiment of this invention. It is a figure which shows the relationship between the zero cut frequency at the time of carrying out zero cut of the rib part of a V-ribbed belt, and the friction coefficient and surface roughness of this rib part surface. It is a figure which shows schematic structure of the experimental apparatus for performing a friction coefficient evaluation test. It is a figure which shows an example of schematic structure of the actual engine accessory drive system which performed the abnormal noise measurement test. It is a figure which shows the test result of an abnormal sound measurement test.

Explanation of symbols

B V-ribbed belt 1 Belt body 2 Adhesive rubber layer 3 Back canvas layer 4 Rib rubber layer 4a Rib portion 4b Short fiber 5 Core wire

Claims (5)

A V-ribbed belt in which a plurality of rib portions extending in the belt length direction are formed on the lower surface of the belt body by grinding,
At least the rubber layer of the rib part contains short fibers so as to protrude from the surface,
The ribbed belt is characterized in that a surface of the rib portion is polished so that a friction coefficient is larger than 1.5. A V-ribbed belt in which a plurality of rib portions extending in the belt length direction are formed on the lower surface of the belt body by grinding,
At least the rubber layer of the rib part contains short fibers so as to protrude from the surface,
The ribbed belt is characterized in that the surface of the rib portion is polished so that the surface roughness Ra is smaller than 6 μm. In any one of Claim 1 or 2,
The V-ribbed belt is characterized in that the surface of the rib portion is polished a predetermined number of times or more with the feed amount of the grinding tool of the rib portion being substantially zero. A V-ribbed belt in which a plurality of rib portions extending in the belt length direction are formed on the lower surface of the belt body by grinding,
A V-ribbed belt, wherein the surface of the rib portion is polished a predetermined number of times or more with a feed amount of the grinding tool of the rib portion being substantially zero so that the surface of the rib portion is in a predetermined surface state. Using the V-ribbed belt according to any one of claims 1 to 4,
The belt is characterized in that the V-ribbed belt is wound around the V-ribbed pulley so as to have a predetermined approach angle, and the V-ribbed pulley is rotated in a predetermined operation state to evaluate abnormal noise during belt running. Abnormal sound evaluation method.

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