JP2006097844A - Power transmission chain and power transmission device using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission chain capable of suppressing sound pressure level of sound generated when operating the chain and to provide a power transmission device using it. <P>SOLUTION: The number of link pitches of the power transmission chain is a plurality and the longest link pitch is 1.1 to 1.25 times the shortest link pitch. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power transmission chain used for a chain type continuously variable transmission of a vehicle and the like, and a power transmission device using the same.

  As a continuously variable transmission (CVT) of an automobile, for example, a drive pulley provided on the engine side, a driven pulley provided on the drive wheel side, and an endless belt-like shape spanned between these pulleys There is something with a chain. Some of these power transmission chains include a plurality of links and a plurality of pins for connecting them together. In such a so-called chain-type continuously variable transmission, traction is generated by a contact frictional force acting between a sheave surface formed of two conical surfaces provided substantially opposite to the inside of each pulley and the end surface of the transmission pin of the chain. Generate power to transmit power. In addition, a chain friction transmission member is provided as a separate member from the pins at predetermined intervals in the chain longitudinal direction, and the traction is generated by the contact friction force acting between the both end surfaces of the chain friction transmission member and the sheave surface. May be transmitted. Then, the effective diameter of each pulley is continuously changed by continuously changing the distance (groove width) between the sheave surfaces of the conical surfaces that are substantially opposed to each other in each of the drive pulley and the driven pulley. As a result, the gear ratio changes continuously (in a stepless manner), and a continuously variable transmission can be performed with a smooth movement different from the conventional gear type.

As a power transmission chain for such a continuously variable transmission, in Patent Document 1, a plurality of links arranged in the longitudinal direction of the chain and having a through hole, a through hole of one link, and a through hole of another link are passed through. Thus, a plurality of pins that connect the links arranged in the chain width direction so as to be bendable in the longitudinal direction of the chain are provided, and belts having different belt pitches have been proposed. According to Patent Document 1, the belt pitch is varied and the pulleys are randomly or regularly arranged in the circumferential direction to randomly or regularly engage the pulley. Can be erased or dispersed.
Japanese Patent Laid-Open No. 3-153941

When further noise reduction has been demanded, the present inventor has succeeded in finding a power transmission chain that can further reduce noise compared to the prior art.
That is, an object of the present invention is to provide a power transmission chain capable of effectively suppressing the sound pressure level of generated sound during chain operation, and a power transmission device using the power transmission chain.

The power transmission chain according to the present invention is used by being bridged between a first pulley having a conical surface sheave surface and a second pulley having a conical surface sheave surface. A power transmission chain that transmits power by contacting end faces of a plurality of chain friction transmission members provided at intervals with the sheave surfaces of the first and second pulleys;
A plurality of links having first and second through holes and arranged in the chain longitudinal direction, and links arranged in the chain width direction by passing through the first through hole of one link and the second through hole of another link A plurality of first pins and second pins connected to each other in the longitudinal direction of the chain are provided, and the first pin and the second pin are rolled and brought into contact with each other so that the chain can be bent.
It has a plurality of link pitches, and the longest link pitch is 1.1 to 1.25 times the shortest link pitch.

  By having a plurality of link pitches, the frequency of the generated sound can be dispersed and the sound pressure level can be reduced. Also, if the longest link pitch among the plurality of link pitches is shorter than 1.1 times the shortest link pitch, the difference in the link pitch is too small and the effect of varying the link pitch is reduced. If the longest link pitch is longer than 1.25 times the shortest link pitch, the length of the longest link pitch becomes too large and the sound generated from the longest link pitch becomes too loud. Or drop. Therefore, the length relationship between the shortest link pitch and the longest link pitch can be optimized by setting the longest link pitch to 1.1 to 1.25 times the shortest link pitch.

From another viewpoint, the power transmission chain according to the present invention is used by being bridged between a first pulley having a conical sheave surface and a second pulley having a conical sheave surface, A power transmission chain for transmitting power by contacting end faces of a plurality of chain friction transmission members provided at predetermined intervals in the longitudinal direction of the chain with the sheave surfaces of the first and second pulleys;
A plurality of links having first and second through holes and arranged in the chain longitudinal direction, and links arranged in the chain width direction by passing through the first through hole of one link and the second through hole of another link A plurality of first pins and second pins are connected to each other in the longitudinal direction of the chain, and the chain can be bent by moving the first pin and the second pin in contact with each other, and a plurality of links. The number of longest link pitches having a pitch is 1/6 to 1/4 of the total number of link pitches.

  When the number of longest link pitches is more than 1/4 with respect to the total number of link pitches, there are many long portions of the link pitch, and a loud sound is generated due to the long link pitch, thereby preventing reduction of the overall generated sound. There is. Also, if the number of the longest link pitch is less than 1/6 of the total number of link pitches, it becomes a state close to a case where all link pitches are made constant, and the above-mentioned effect due to mixing different link pitches is reduced. Become. Therefore, the mixing ratio of a plurality of link pitches having different lengths can be optimized by setting the number of the longest link pitches to 1/6 to 1/4 of the total number of link pitches.

  Further, when the power transmission chain having the configuration of the power transmission chain according to the above two inventions is combined, it is generated due to the synergistic effect of the optimization effect of the link pitch length ratio and the optimization effect of the link pitch mixture number ratio. Sound can be further reduced.

  In each of the power transmission chains described above, the locus of the contact position in the rolling contact movement between the first pin and the second pin is a circular involute, and the basic circle radius of the involute differs between two or more types of the first pin and the second pin. A configuration having a set is preferable. Polygonal vibration can be suppressed by making the trajectory of the contact position an involute of a circle. Furthermore, by providing a set of two or more types of pins having different basic circle radii of the involute, the resonance of the polygonal vibration is suppressed, and the generated sound suppression effect by the involute is further enhanced.

And the power transmission device of the present invention comprises a first pulley having a conical sheave surface,
A power transmission device comprising: a second pulley having a conical sheave surface; and a power transmission chain used by being spanned between the first and second pulleys, wherein the power transmission chain Is any one of the above-mentioned ones.
If it does in this way, since each power transmission chain mentioned above was used, it can be set as the power transmission device provided with the effect of each said chain.

  When either the first pin or the second pin is a transmission pin, the transmission pin of the first pin and the second pin is generally referred to as a “pin”, and the one that is not the transmission pin Generally referred to as “strip” or “interpiece”. Therefore, in the following, the transmission pin of the first pin or the second pin is simply referred to as “pin”, and the non-transmission pin is referred to as “strip”.

  As described above, the power transmission chain and the power transmission device of the present invention have different link pitches and appropriately set the length or number ratio of the longest link pitch and the shortest link pitch. The frequency is efficiently dispersed, and the peak value of the sound pressure level of the generated sound can be reduced.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view schematically showing a main configuration of a chain (hereinafter also simply referred to as “chain”) 1 for a chain type continuously variable transmission according to an embodiment of the present invention. The chain 1 according to the present embodiment has an endless belt shape as a whole, a plurality of metal links 2, a plurality of metal pins 3 for connecting the links 2 to each other, and a pin longitudinal direction than these pins 3 It consists of a plurality of strips 5 that are slightly shorter in length. The link 2 and the pin 3 are made of metal such as bearing steel. The plurality of strips 5 have the same shape, but the cross-sectional shapes of the plurality of pins 3 are not all the same, and as will be described later, the contact surface is different so that the involute that is the locus of rolling contact movement between the pins 3 and the strip 5 is different. Two types of pins 3 having different shapes of 3a are included. The end surface 3c of the pin 3 is located outside the end surface of the strip 5 in the chain width direction, and this end surface 3c comes into contact with the sheave surface of the pulley. That is, in this chain 1, the pin 3 is a transmission pin that also serves as a chain friction transmission member.
In FIG. 1, some of the links near the center of the chain 1 in the width direction are partially omitted.

  FIG. 2A is a plan view of the link 2. As shown in FIGS. 2A and 1, each link 2 has an outer shape obtained by rounding the corners of a substantially rectangular plate-like member, and the link longitudinal direction (matches the chain longitudinal direction). ) In parallel with two through holes 4. One strip 5 and one pin 3 are inserted through each of the through holes 4. A plurality of links 2 are arranged overlapping in the chain width direction, and are arranged while sequentially shifting the position in the chain longitudinal direction. A plurality of links 2 are connected to each other by inserting a common pin 3 through the through holes 4 of the links 2 that are arranged in the chain width direction while different positions in the longitudinal direction of the chain. Chain 1 is assumed.

  In the chain 1, two types of links 2 having different lengths in the longitudinal direction are mixed. That is, the link 2 includes a long link 2f having a relatively long longitudinal length and a short link 2h having a relatively short length. FIG. 3 is a side view of the chain 1 in an unbent state. As shown in FIG. 3, the longitudinal length X of the long link 2f is longer than the longitudinal length Y of the short link 2h. ing. That is, X> Y.

  Both the long link 2f and the short link 2h have two through holes 4 in each link. Hereinafter, the short link 2h will be described as an example, but the same applies to the long link 2f. As shown in FIG. 2A, the two through holes 4 of the short link 2h are composed of a first through hole 41 and a second through hole 42 arranged in the chain longitudinal direction. The first through hole 41 and the second through hole 42 are different in shape from each other. As described later, the bend in the chain longitudinal direction of the chain 1 (the bend so that the chain 1 can be wound around a circular pulley). ) Is possible. In the chain 1, the first through hole 41 is located on one side in the chain longitudinal direction with respect to the second through hole 42 in common to all the links 2. In other words, in each of all the links 2, the second through hole 42 is located on the other side in the chain longitudinal direction with respect to the first through hole 41.

  FIG. 2B is a diagram showing a state in which a pair of pins 3 and strips 5 are inserted into the first through hole 41 and the second through hole 42, respectively. The pair of pins 3 and strips 5 pass through the first through hole 41 of one link 2 and the second through hole 42 of another link 2 among the plurality of links 2 in the chain width direction. The linked links 2 are connected to be able to bend in the longitudinal direction of the chain.

  As shown in FIG. 2 (b), when one link 2 alone is viewed, the pin 3 is press-fitted and fixed in the first through hole 41, and the strip 5 in contact with the pin 3 is the first through hole 41. Is inserted into the first through hole 41 so as to be movable through a predetermined gap. On the other hand, in the second through hole 42 in the link 2, the strip 5 is press-fitted and fixed in the second through hole 42, and the pin 3 in contact with the strip 5 is predetermined with respect to the second through hole 42. It is inserted through the gap and fitted into the second through hole 42 so as to be movable.

  As shown in FIG. 1, when two links 2 adjacent to each other in the chain width direction with different positions in the longitudinal direction of the chain are viewed, they are fixed to the first through hole 41 of one link 2 and the other links 2. The pin 3 movably fitted in the second through hole 42 of the first link 2 and the first through hole 41 of one link 2 movably fitted and fixed to the second through hole 42 of the other link 2. The strip 5 is provided. The pair of the pin 3 and the strip 5 inserted in the same through-hole 4 (the first through-hole 41 or the second through-hole 42) is relatively rolled and moved so that the chain 1 is moved in the longitudinal direction of the chain. It can be bent.

  The link pitch of the chain 1 of the present invention is not constant, and has two types of link pitches. Specifically, as shown in FIG. 3, it has a longest link pitch P1 that is a relatively long link pitch and a shortest link pitch P2 that is a relatively short link pitch. As shown in FIG. 3, the link pitch is a contact between the side surface of the chain friction transmission member (the end surface 3c of the pin 3 in this embodiment) and the sheave surface (the side surface of the transmission pin and the sheave surface are in surface contact or line contact). In this case, when the contact surface or the center of gravity of the contact line) S is considered, it is the distance between the contacts S adjacent in the chain longitudinal direction (chain longitudinal distance).

As described above, in this embodiment, the long link 2f and the short link 2h are used as the two types of links 2 having different lengths, but the first through hole 41 and the second through hole 42 in each link are used. Comparing the distance between the through holes (not shown) which is the distance (link longitudinal direction distance), the long link 2f has a longer distance between the through holes than the short link 2h. Therefore, the link pitch in the long link 2f is longer than the link pitch in the short link 2h. That is, as shown in FIG. 3, the link pitch in the long link 2f is the longest link pitch P1 described above, and the link pitch in the short link 2h is the shortest link pitch P2 described above.
In this embodiment, the length of the link is increased as the link is configured to have a longer link pitch. However, the link pitch can be increased without increasing the length of the link. For example, even if the links have the same length, the link pitch can be made different by making the distance between the through holes in each link different and making the distance between the pins adjacent in the chain longitudinal direction different. Even when the distance between the through holes is not different, the link pitch can be made different by changing the distance between the contacts S by changing the shape of the convex curved surface of the side surface of the transmission pin.

The longest link pitch P1 and the shortest link pitch P2 may be arranged regularly. However, the random (irregular) arrangement increases the frequency dispersion effect, and the peak of the sound pressure level is easily reduced. preferable. Note that even if it is random, it does not have to be completely random over the entire circumference of the chain 1.
In this embodiment, two types of link pitches, the longest link pitch P1 and the shortest link pitch P2, are used. However, the link pitch may be three or more types.

The longest link pitch P1 that is the longest link pitch among the plurality of link pitches is 1.1 to 1.25 times the shortest link pitch P2 that is the shortest link pitch.
If the longest link pitch P1 among the plurality of link pitches is too short with respect to the shortest link pitch P2, the difference in the link pitch is too small and the effect of changing the link pitch is reduced. Further, if the longest link pitch P1 is too long with respect to the shortest link pitch P2, the longest link pitch P1 becomes too long and the sound generated from the longest link pitch P1 becomes too loud, or the design flexibility of the link length is large. Or drop. As in the present embodiment, by setting the longest link pitch P1 to 1.1 to 1.25 times the shortest link pitch P2, the relationship between the shortest link pitch and the longest link pitch can be optimized.

  Furthermore, in the present embodiment, the number of long links 2f constituting the longest link pitch P1 is equal to the sum (the total number of links) of the short links 2h constituting the shortest link pitch P2 and the long links 2f. Thus, the number of longest link pitches P1 is made 1/6 to 1/4 of the total number of link pitches (the sum of the number of longest link pitches and the number of shortest link pitches). Yes. If the number of the longest link pitches P1 is more than ¼ of the total number of link pitches, a portion with a long link pitch (longest link pitch P1) increases and a loud sound resulting from the long link pitch P1 is generated. May prevent the reduction of sound generation. Further, if the number of the longest link pitches P1 is too smaller than 1/6 of the total number of link pitches, it becomes a state close to a case where all the link pitches are made constant, and the above-mentioned effect by mixing different link pitches P1 and P2 is obtained. Will decrease. Therefore, the mixture ratio of the link pitch can be optimized by setting the number of the longest link pitches P1 to 1/6 to 1/4 of the total number of link pitches.

  When the chain 1 is bent, the pin 3 and the strip 5 inserted in the same through-hole 4 are in rolling contact with each other (strictly speaking, rolling contact including some sliding contact, also referred to as rolling sliding contact). Will do. FIG.2 (c) is a figure which shows the mode of the displacement of the pin 3 and the strip 5 which move while rolling-contacting. As shown in the figure, in the first through hole 41, only the strip 5 of the pin 3 and the strip 5 moves (rotates) with respect to the first through hole 41, and in the second through hole 42, the pin 3 and the strip 5 Only the pin 3 moves (rotates) with respect to the second through hole 42. The pin 3 and the strip 5 are always in contact in the entire range of rolling contact movement, so that transmission loss is minimized and high power transmission efficiency is ensured.

  The locus of the contact position in the rolling contact movement between the pin 3 and the strip 5 is an involute of a circle in the side view of the chain 1. Thus, in order to make the locus of the contact position a circular involute, the cross-sectional shape of the contact surface 3a (see FIG. 2B) of the pin 3 with the strip 5 is an involute curve having a predetermined basic circle radius, On the other hand, the contact surface 5a of the strip 5 is a flat surface (shown as a straight line in the side view of FIGS. 2 and 3). The cross-sectional shape of the entire contact surface 3a is not required to be an involute curve, and the cross-sectional shape of the contact surface 3a in a range where the pin 3 and the strip 5 are in rolling contact (hereinafter also referred to as a working side surface) is involute. A curve may be used.

In order to make the trajectory of the contact position between the pin 3 and the strip 5 an involute of a circle, the contact surface 3a of the pin 3 is involute and the contact surface 5a of the strip 5 is a flat surface as in this embodiment. Conversely, the contact surface 5a of the strip 5 may be an involute shape, and the contact surface 3a of the pin 3 may be a flat surface. In addition, by making both the contact surfaces 3a and 5a curved surfaces, the locus can be an involute of a circle. In this case, the cross-sectional shapes of the action side surfaces of the contact surface 3a and the contact surface 5a are the same. Preferably it is done.
Note that the involute in the present invention includes an involute approximated (substantially involute). This is because polygonal vibration can be suppressed to some extent even if it approximates involute.

  The chain 1 is provided with two types of pins 3 having different base circle radii of the involute in the cross-sectional shape of the contact surface 3a (the working side surface). As a result, a set of two types of pins 3 and strips 5 having different base circle radii of the involute that is the locus of the mutual contact position is formed.

  FIG. 4 is a perspective view showing a schematic configuration of a chain type continuously variable transmission 50 as an embodiment of the power transmission device of the present invention provided with the chain 1. This chain-type continuously variable transmission 50 can be used as a transmission for an automobile, for example, and includes a metal drive pulley 10 as a first pulley and a metal driven pulley 20 as a second pulley. The endless belt-like chain 1 is provided between the pulleys 10 and 20. The pulleys 10 and 20 are made of metal such as bearing steel. In FIG. 4, a part of the cross section of the chain 1 is clearly shown for easy understanding.

  FIG. 5 is a cross-sectional view of the continuously variable transmission 50 in the pulley 10 or 20 (a cross-sectional view in a cross section along the radial direction of the pulleys 10 and 20). As shown in the figure, the end surface 3c of the pin 3 in the chain 1 is in contact with conical sheave surfaces 12a, 13a (22a, 23a) facing each other inside the pulley 10 (20), and this contact friction force The traction is transmitted by. Thus, the pin 3 is a transmission pin that also serves as a chain friction transmission member.

  In the chain 1, the arrangement order of the short links 2h and the long links 2f is random (irregular), so that the arrangement order of the longest link pitch P1 and the shortest link pitch P2 is also random (irregular). Yes. In addition, when the basic circle radius of the involute which is the locus of the contact position in the rolling contact movement between the pin 3 and the strip 5 is two types R1 and R2 (different from R1 and R2), the basic circle radius of the involute is The pins 3 of R2 as well as the pins 3 of R1 are arranged in the chain longitudinal direction in a random (irregular) order.

Since the locus of the contact position between the pin 3 and the strip 5 is an involute of a circle, polygonal vibration is reduced.
This polygonal vibration will be described. FIG. 6 shows an outline of a locus of a pin when a conventional general chain is wound around a pulley in a side view of the chain. This figure shows the pin trajectory when the chain is wound around a pulley (not shown) located on the right side of the drawing while moving from the left side to the right side of the drawing. An example of a distance (mm) from a biting position that is a position where biting starts is shown. Since the chain is wound around the pulley on the front side (right side in the drawing) of the chain moving direction from the biting position, the locus of the pin has an arc shape corresponding to the winding radius of the chain 1. However, the locus of the pin oscillates up and down as if the trajectory of the pin hit a wave on the front side (left side in the drawing) of the chain traveling direction from the biting position. This is polygonal vibration. Such polygonal vibration is caused by the fact that the chain connects the links, and when it is bent in the longitudinal direction of the chain, it does not become a complete arc but becomes a polygon. That is, in this case, the tangential direction of the pulley and the pin entry direction are different at the biting position, and an entry angle shown in FIG. 6 is generated, and the pin comes into contact with the pulley while descending. The amount of pin lowering at the moment when the pulley and the pin come into contact is shown as the initial biting position change amount. When the pin descends, the chain moves up and down, and polygonal vibration is generated by repeating the vertical vibration. If the locus of the contact position described above is an involute of a circle, the approach angle (see FIG. 6) is reduced, the initial biting position change amount is reduced, and polygonal vibration is suppressed.
Furthermore, since two or more pairs of pins 3 and strips 5 having different base circle radii of the involute are formed, resonance of polygonal vibration is suppressed and sound generated by the polygonal vibration is reduced.

  The main principle of sound generation from the chain is explained as follows. In the chain type continuously variable transmission 50 shown in FIG. 4, when the chain 1 enters the sheave surfaces 12a, 13a, 22a, and 23a of the pulleys 10 and 20, the pin 3 of the chain 1 collides with these sheave surfaces. Press the sheave surface. By this reaction, the pin 3 is pushed from the end surface 3c from the sheave surface, and the pin 3 is deformed by receiving a force in the direction of compressing the length in the longitudinal direction of the pin (this deformation is hereinafter referred to as compression deformation). By this force, the pin 3 is elastically deformed and then deformed so as to recover the original shape (this deformation is hereinafter referred to as recovery deformation). In this recovery deformation, the sheave surfaces 12a, 13a, 22a, 23a will be pressed. Such a principle (hereinafter also referred to as a sound generation principle) causes the pulleys 10 and 20 to vibrate, and this vibration generates sound.

  In the present embodiment, since the link pitch is different between the long link 2f and the short link 2h, the contact interval between the pin 3 and the pulley is also different. Therefore, the period of the sound generated by the contact between the pin 3 and the pulley is dispersed, the sound frequency is dispersed, and the generated sound pressure level peak is reduced. Furthermore, since the ratio of the length and the number of the longest link pitch and the shortest link pitch is optimized, the peak of the sound pressure level is further reduced.

  In the above embodiment, the case has been described where there are two types of involute basic circle radii, but there may be three or more types. However, if the number of types of the basic circle radius is excessively increased, the parts management cost and the manufacturing cost are increased, for example, it is necessary to increase the types of pins 3. Accordingly, it is preferable that the link pitch and the basic circle radius of the involute are two to three, respectively, because a sufficient noise reduction effect can be obtained and the balance with cost is good.

  Here, a mechanism in which the continuously variable transmission 50 functions as a transmission will be described. The drive pulley 10 shown in FIG. 4 is attached to an input shaft 11 connected to the engine side so as to be integrally rotatable, and is opposed to the fixed sheave 12 having a conical sheave surface 12a and the sheave surface 12a. And a movable sheave 13 having a conical surface 13a. The chain 1 is sandwiched between the sheave surfaces 12a and 13a from the side surface with strong pressure. In addition, a hydraulic actuator (not shown) is connected to the movable sheave 13 so that the movable sheave 13 is movable in the axial direction of the input shaft 11. When the movable sheave 13 moves, the facing distance (groove width) of the facing sheave surfaces 12a, 13a changes. Since the chain width of the chain 1 is always constant, the chain 1 is wound at a radial position corresponding to the chain width, and the winding radius of the chain 1 changes.

On the other hand, also in the driven pulley 20, the winding radius of the chain 1 changes on the same principle as the drive pulley 10.
The driven pulley 20 is attached to an output shaft 21 connected to the drive wheel side so as to be integrally rotatable, and is disposed so as to face the fixed sheave 22 having a conical sheave surface 22a and the sheave surface 22a. And a movable sheave 23 having a conical sheave surface 23a. The chain 1 is sandwiched between the sheave surfaces 22a and 23a from the side surface with a strong pressure. Further, a hydraulic actuator (not shown) is connected to the movable sheave 23, so that the movable sheave 23 is movable in the axial direction of the output shaft 21. When the movable sheave 23 moves, the facing distance (groove width) of the facing sheave surfaces 22a and 23a changes. Since the chain width of the chain 1 is always constant, the chain 1 is wound at a radial position corresponding to the chain width, and the winding radius of the chain 1 changes.

When shifting to a lower gear state, the groove width on the drive pulley 10 side is enlarged by the movement of the movable sheave 13 to reduce the winding radius of the drive pulley 10 of the chain 1 and at the same time on the driven pulley 20 side. The groove width is reduced by the movement of the movable sheave 23 to increase the winding radius of the driven pulley 20 of the chain 1.
Conversely, when shifting to a higher gear state, the groove width on the drive pulley 10 side is reduced by the movement of the movable sheave 13 to increase the winding radius of the drive pulley 10 of the chain 1 and at the same time the driven pulley 20 side. The groove width is increased by the movement of the movable sheave 23 to reduce the winding radius of the driven pulley 20 of the chain 1. In this way, a continuously variable transmission function is achieved.
In the power transmission device such as the chain type continuously variable transmission 50, the chain of the present invention can reduce the sound pressure level of the generated sound during the operation.

  As described above, it is preferable to arrange the plurality of link pitches and the plurality of involute shapes in an irregular order (randomly), but in order to obtain an optimal arrangement among such irregular arrangements, For example, it is possible to determine an optimal arrangement with a small generated sound by performing experiments with a large number of chains in which each arrangement pattern is randomly changed or performing a simulation with a computer.

  Here, the preferable aspect of the cross-sectional shape of the contact surface 3a of the pin 3 in the chain 1 of the said embodiment is demonstrated. FIG. 7 is a view for explaining this preferable shape, and is a side view of the pin 3 as viewed from the end surface 3c direction. Of the contact surface 3a of the pin 3, the working side surface that makes rolling contact with the strip 5 is the contact line A between the pin 3 and the strip 5 in a state where the chain 1 is not bent (shown as a point in FIG. The contact line B (shown as a dot in FIG. 10). And the cross-sectional line of the contact surface 3a including the cross-sectional line of this action side surface is comprised by the smooth convex curve.

  In the involute curve on the working side in the cross section of the pin 3, it is preferable that the center M of the basic circle radius Rb is arranged on the tangent line SA at the point A of the cross section line of the pin 3. The basic circle radius Rb is about a distance dA (not shown) from the winding center (not shown in FIG. 7) to the point A in a state where the chain 1 is wound around a pulley (not shown in FIG. 7). Polygonal vibration is minimized and preferable. However, in the case of CVT for automobiles, for example, the wrapping radius changes within a predetermined range, so the distance dA also changes. Therefore, in this case, when the dA when the winding radius is the maximum is dAx and the dA when the winding radius is the minimum is dAn, 1/4 (dAn) ≦ Rb ≦ 2 (dAx). Thus, it is preferable to set the basic circle radius Rb. Furthermore, when different involute base circle radii are used, it is preferable to use a plurality of types of base circle radii Rb within a range of 1/4 (dAn) ≦ Rb ≦ 2 (dAx).

(Verification of sound pressure level reduction effect by example)
In order to confirm the effect of reducing the sound pressure level of the present invention, two types of power transmission devices of the example and the comparative example were produced and verified.
First, the effect of the link pitch ratio was confirmed by comparing the sound pressure level of the generated sound between Example 1 and Comparative Example 1. In Example 1, the link pitch ratio (numerical value obtained by dividing the longest link pitch by the shortest link pitch) was 1.19, whereas in Comparative Example 1, the link pitch ratio was 1.29. The results are shown in FIG.

  Moreover, the effect of the ratio of the number of link pitches was confirmed by comparing the sound pressure level of the generated sound in Example 2 and Comparative Example 2. In the second embodiment, the ratio of the number of link pitches (the value obtained by dividing the number of longest link pitches by the total number of link pitches) is 0.17, whereas in the second comparative example, the ratio of the number of link pitches is 0.37. It was. The results are shown in FIG.

In all of Examples 1 and 2 and Comparative Examples 1 and 2 (hereinafter also referred to as all examples), all parts other than the chain are common, and the measurement conditions of the generated sound are also the same. In all of the examples, the basic circle radius of the involute is one type without being mixed. In all examples, the arrangement order of the shortest link pitch and the longest link pitch is random.
Furthermore, in comparison with Example 1 and Comparative Example 1, the rotational speed of the power transmission device was 2000 rpm, the speed increase rate was 0.833, the load torque was 30 Nm, and the clamp pressure was 1.65 Mpa. In comparison with Example 2 and Comparative Example 2, the rotational speed of the power transmission device was 3000 rpm, the speed increase rate was 1, the load torque was 0 Nm, and the clamp pressure was 1.65 Mpa.

As is clear from FIGS. 8A and 8B, the sound pressure level of Example 1 is lower than that of Comparative Example 1 for both the maximum sound pressure level (maximum peak value) and the overall value. Yes.
9A and 9B, the sound pressure level of Example 2 is lower than that of Comparative Example 2 for both the maximum sound pressure level (maximum peak value) and the overall value. It has become.

  In the above-described embodiment, only the case where the pin 3 also serves as a chain friction transmission member is illustrated, but a chain friction transmission member different from the first pin and the second pin that are in rolling contact with each other may be provided. For example, a plurality of chain friction transmission members (friction blocks), which are rod-like members extending in the chain width direction in parallel with the first pin and the second pin and projecting on both sides of the chain width direction from these pins, are provided at predetermined intervals in the chain longitudinal direction. A structure may be provided in which both ends of the chain friction transmission member are in contact with the sheave surface of the pulley to transmit power.

It is a perspective view showing typically the principal part composition of the chain for chain type continuously variable transmission concerning one embodiment of the present invention. (A) is a side view of a single link, (b) is a side view of a state in which a pin and a strip are inserted into the link, and (c) is a diagram showing an aspect of rolling contact movement between the pin and the strip. . It is a side view of the chain of FIG. It is a perspective view showing a schematic structure of a chain type continuously variable transmission using a chain according to an embodiment of the present invention. It is sectional drawing of the pulley part in the continuously variable transmission of FIG. It is a figure which shows the locus | trajectory of a pin when the conventional general power transmission chain is wound around a pulley. It is a figure for demonstrating a preferable involute shape. It is the bar graph which compared the generated sound of Example 1 and Comparative Example 1, (a) is the graph which displayed the maximum sound pressure level of the generated sound, (b) is the graph which displayed the overall value of the generated sound. It is the bar graph which compared the generated sound of Example 2 and Comparative Example 2, (a) is the graph which displayed the maximum sound pressure level of the generated sound, (b) is the graph which displayed the overall value of the generated sound.

Explanation of symbols

1 Chain 2 Link 3 Pin (1st pin or 2nd pin)
3c Both sides of pin (end face of chain friction transmission member)
4 Through-hole 41 First through-hole 42 Second through-hole 5 Strip (first pin or second pin)
10 Drive pulley (first pulley)
12a Conical surface sheave surface 13a Conical surface sheave surface 20 Driven pulley (second pulley)
50 Chain type continuously variable transmission P1 Longest link pitch (longest link pitch)
P2 Shortest link pitch (shortest link pitch)

Claims (5)

A plurality of pulleys used between a first pulley having a conical surface sheave surface and a second pulley having a conical surface sheave surface are provided at predetermined intervals in the chain longitudinal direction. A power transmission chain for transmitting power by contacting an end surface of a chain friction transmission member with a sheave surface of the first and second pulleys;
A plurality of links having first and second through holes and arranged in the chain longitudinal direction, and links arranged in the chain width direction by passing through the first through hole of one link and the second through hole of another link A plurality of first pins and second pins connected to each other in the longitudinal direction of the chain are provided, and the first pin and the second pin are rolled and brought into contact with each other so that the chain can be bent.
A power transmission chain having a plurality of link pitches, wherein the longest link pitch is 1.1 to 1.25 times the shortest link pitch.   2. The power transmission chain according to claim 1, wherein the power transmission chain has a plurality of link pitches, and the number of the longest link pitches is 1/6 to ¼ of the total number of link pitches. A plurality of pulleys used between a first pulley having a conical surface sheave surface and a second pulley having a conical surface sheave surface are provided at predetermined intervals in the chain longitudinal direction. A power transmission chain for transmitting power by contacting an end surface of a chain friction transmission member with a sheave surface of the first and second pulleys;
A plurality of links having first and second through holes and arranged in the chain longitudinal direction, and links arranged in the chain width direction by passing through the first through hole of one link and the second through hole of another link A plurality of first pins and second pins connected to each other in the longitudinal direction of the chain are provided, and the first pin and the second pin are rolled and brought into contact with each other so that the chain can be bent.
A power transmission chain having a plurality of link pitches, wherein the number of longest link pitches is 1/6 to 1/4 of the total number of link pitches.   The locus of the contact position in the rolling contact movement between the first pin and the second pin is an involute of a circle, and the involute has a set of two or more types of first and second pins having different basic circle radii. The power transmission chain according to any one of claims 1 to 3. A first pulley having a conical sheave surface;
A second pulley having a conical sheave surface;
A power transmission chain used between the first and second pulleys;
A power transmission device comprising:
The power transmission chain according to any one of claims 1 to 4, wherein the power transmission chain.

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