JP4529073B2 - Power transmission chain and power transmission device including the same - Google Patents

Description

  The present invention relates to a power transmission chain and a power transmission device including the power transmission chain.

An endless power transmission chain used in a power transmission device such as a pulley-type continuously variable transmission (CVT) of an automobile has a plurality of links arranged in the chain traveling direction and links adjacent to each other in the chain traveling direction. Are connected by a pair of pins (for example, see Patent Document 1).
Japanese Utility Model Publication No. 64-15840

Among such power transmission chains, there is one in which one pin is brought into contact with a pulley, and the other pin is slid and brought into contact with one pin.
Such a power transmission chain and a power transmission device including the same are required to be downsized while ensuring practically sufficient durability. The present invention aims at this.

The inventor of the present application tried to reduce the thickness of the pair of pins in order to achieve downsizing in the power transmission chain. However, one pin that contacts the pulley needs to secure a certain contact area with the pulley, and there is a limit to reducing the thickness. Moreover, even if the other pin is made thinner, there is a limit to improvement in strength (durability) only by making it thinner.
Therefore, the present invention includes a plurality of links arranged in the chain traveling direction, and a corresponding link using a first pin that engages with a power transmission target and a second pin that is in rolling contact with the first pin. in the power transmission chain are interconnected, each said at least one surface and interior of the second pin, made from a low low hardness portion hardness as compared with the first pin surface, the plurality of links, has a first and a through hole which the second pin is inserted, the periphery of each through hole, characterized in that it consists of a lower low hardness portion hardness compared to the hardness of the first and second pin surface It is what.

According to the present invention, the low hardness portion of the second pin is superior in toughness compared to the surface of the first pin, and exhibits a buffering action to absorb the impact received from the first pin or the like. Can do. As a result, the second pin can be provided with sufficient strength, and the second pin can be reduced in size (thinned) while ensuring practically sufficient durability. As a result, the power transmission chain can be reduced in size while ensuring practically sufficient durability. Further, for example, when the corresponding first and second pins are inserted through the respective through holes during the manufacture of the chain, the peripheral edges of the respective through holes damage the surfaces of the corresponding first and second pins. Can be prevented. As a result, the strength of the first and second pins can be reliably maintained, and the durability can be further improved.

In the present invention, the hardness of the low hardness portion of the second pin may be 5 or more lower in Rockwell hardness HRC than the hardness of the surface of the first pin. In this case, compared to the toughness of the surface of the first pin, the toughness of the low hardness portion of the second pin can be made extremely excellent. As a result, the buffering action of the second pin can be made extremely excellent, and further durability can be secured .

  In the present invention, the plurality of links include first and second links, and each of the links has a front through hole and a rear through hole arranged in the front and rear in the chain traveling direction, and the first pin Is press-fitted and fixed in the front through hole of the first link and is movably fitted into the rear through hole of the second link, and the second pin is movably fitted into the front through hole of the first link. In some cases, it is inserted and fixed in the rear through hole of the second link.

In this case, for example, when the first pin comes into contact with the sheave surface of the pulley to transmit power, the second pin rolls and comes into sliding contact with the first pin, so that the chain progresses between the links. The direction can be bent. As a result, the first pin hardly rotates with respect to the sheave surface, and it is possible to reduce friction loss and ensure high transmission efficiency.
In the present invention, the first and second pulleys each having a pair of conical sheave surfaces facing each other and the pulleys wound around these pulleys are engaged with the sheave surface as a power transmission target. In some cases, the power transmission chain for transmitting power is provided. In this case, a power transmission device that is excellent in durability and compact can be realized.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a perspective view schematically showing a configuration of a main part of a power transmission chain (hereinafter simply referred to as a chain) for a chain type continuously variable transmission according to an embodiment of the power transmission chain of the present invention. . FIG. 2 is a cross-sectional plan view of the main part of the chain shown in FIG. 3 is a cross-sectional view taken along the line II-II in FIG.

Referring to FIGS. 1 and 2, the chain 1 includes a plurality of links 2, a first row 51, a second row 52, and a third row 53 as a pair of pins that are in rolling contact with each other. A plurality of first and second pins 3 and 4 are provided. The rolling sliding contact means a contact including at least one of a rolling contact and a sliding contact.
2 and 3, each link 2 is formed in a plate shape from, for example, carbon steel (SK5). This carbon steel is heat-treated (quenched and tempered) and has a uniform hardness as a whole. That is, each link 2 has a uniform hardness as a whole. Each link 2 includes a front end portion 7 and a rear end portion 8 as a pair of end portions arranged in front and rear in the chain traveling direction X, and a front through hole 9 and a rear through hole 10 are respectively provided in these end portions 7 and 8. Is formed.

Each of the first row 51, the second row 52, and the third row 53 includes a plurality of links 2 arranged in the chain width direction W. In each of the first to third columns 51 to 53, the links 2 in the same column have the same (aligned) positions in the chain traveling direction X. The first to third rows 51 to 53 are arranged along the chain traveling direction X.
Each first pin 3 is a rod-like body extending in the chain width direction W. A pair of end portions of each first pin 3 protrudes in the chain width direction W from the link 2 arranged at the pair of end portions in the chain width direction W. Power transmission surfaces 5 and 6 for contacting (engaging) a sheave surface as a power transmission target are provided on a pair of end surfaces of each first pin 3. Since each first pin 3 contributes directly to power transmission by its power transmission surfaces 5 and 6, it is made of a high-strength material such as bearing steel (for example, SUJ2). This high-strength material is heat-treated (quenched and tempered) and has a uniform hardness as a whole. That is, each first pin 3 has a uniform hardness as a whole.

  Each second pin 4 (also referred to as a strip or an interpiece) is a rod-like body extending in the chain width direction W, and is formed slightly shorter than the first pin 3 so as not to contact the sheave surface. . The cross-sectional shape of each second pin 4 is a flat oval shape that is thinner than the first pin 3. Each second pin 4 is formed of the same material as the first pin 3, that is, a high-strength material that has been heat-treated, and has a uniform hardness as a whole.

Corresponding links 2 in corresponding first to third rows 51 to 53 are connected to each other using corresponding first and second pins 3 and 4.
Specifically, the front through hole 9 of each link 2 of the first row 51 as the first link and the rear through hole 10 of each link 2 of the second row 52 as the second link are: The links 2 in the first and second rows 51 and 52 are connected to each other by the first and second pins 3 and 4 that are arranged in the chain width direction W and correspond to each other. Are coupled to be able to bend in the chain traveling direction X.

Similarly, the front through hole 9 of each link 2 in the second row 52 and the rear through hole 10 of each link 2 in the third row 53 correspond to each other side by side in the chain width direction W. The links 2 in the second and third rows 52 and 53 are connected to each other so as to be bent in the chain traveling direction X by the first and second pins 3 and 4 inserted through the through holes 9 and 10.
In FIG. 2, only one each of the first to third columns 51 to 53 is illustrated, but the first to third columns 51 to 53 are arranged so as to repeat along the chain traveling direction X. Yes. The links 2 in two rows adjacent to each other in the chain traveling direction X are sequentially connected by the first and second pins 3 and 4 to form an endless chain 1.

Each first pin 3 is press-fitted and fixed (fitted) into the front through hole 9 of the corresponding link 2 to restrict relative rotation with respect to the link 2 and loosely fitted into the rear through hole 10 of the corresponding link 2. Thus, relative movement (rotation) with respect to the link 2 is enabled.
Specifically, the first pin 3 is press-fitted and fixed in the front through-hole 9 of each link 2 in the first row 51, and relative rotation with respect to each link 2 in the first row 51 is restricted, It is loosely fitted in the rear through-hole 10 of each link 2 in the second row 52 so that it can rotate relative to each link 2 in the second row 52. Similarly, the first pin 3 is press-fitted and fixed in the front through hole 9 of each link 2 in the second row 52 and loosely fitted in the rear through hole 10 in each link 2 in the third row 53. Yes.

In addition, each second pin 4 is loosely fitted in the front through hole 9 of the corresponding link 2 so as to be able to move (rotate) relative to the link 2, and in the rear through hole 10 of the corresponding link 2. The relative rotation with respect to the link 2 is restricted by press-fitting (fitting).
Specifically, the second pin 4 is loosely fitted in the front through-hole 9 of each link 2 in the first row 51 and can be relatively moved (rotated) with respect to each link 2 in the first row 51. At the same time, it is press-fitted and fixed in the rear through hole 10 of each link 2 in the second row 52, and the relative rotation of each link 2 in the second row 52 with respect to each link 2 is restricted. Similarly, the second pin 4 is loosely fitted in the front through hole 9 of each link 2 in the second row 52 and is press-fitted and fixed in the rear through hole 10 of each link 2 in the third row 53. Yes.

  With the above configuration, when the links 2 adjacent to each other in the chain traveling direction X are bent in the chain traveling direction X, the corresponding second pins 4 are in rolling contact with the adjacent first pins 3. At this time, when the chain 1 is viewed from the outside in the chain width direction W, the contact line T between the first pin 3 and the second pin 4 with respect to the first pin 3 (in FIG. 3, vertical to the paper surface). The trajectory of a straight line extending in the direction is substantially an involute curve.

Specifically, as shown in FIG. 3, a contact portion 12 that can come into contact with the corresponding second pin 4 out of the surface 11 (circumferential surface) of each first pin 3 is formed in an involute cross section. The Moreover, the contact part 14 which can contact the corresponding 1st pin 3 among the surface 13 (circumferential surface) of each 2nd pin 4 is formed in a flat surface (cross-sectional linear shape).
One of the features of the present embodiment is that each second pin 4 is provided with a low hardness portion having a hardness lower than that of the corresponding surface 11 of the first pin 3. The toughness of the steel is excellent and sufficient strength is provided.

  Specifically, as described above, each second pin 4 has a uniform hardness as a whole, and the whole is a low hardness portion. The hardness of each second pin 4 is set to 53, for example, as Rockwell hardness HRC. As described above, each first pin 3 has a uniform hardness as a whole, and Rockwell hardness HRC is set to 58, for example. Thus, the hardness of the second pin 4 is set to 5 lower in Rockwell hardness HRC than the hardness of the first pin 3 (surface 11 thereof).

Note that the hardness of the second pin 4 may be lower by less than 5 (excluding 0) or lower than 5 by the Rockwell hardness HRC as compared with the hardness of the first pin 3. .
The hardness difference between the first pin 3 and the second pin 4 is provided as follows when the chain 1 is manufactured. That is, for example, both the first and second pins 3 and 4 are quenched under the same conditions, but by increasing the tempering temperature of the second pin 4, a hardness difference is provided between them.

Another feature of the present embodiment is that the peripheral edges 15 and 16 of the through holes 9 and 10 of each link 2 are compared with the hardness of the surfaces 11 and 13 of the corresponding first and second pins 3 and 4. By providing a low hardness portion having a low hardness, the peripheral edges 15 and 16 are prevented from damaging the surfaces 11 and 13 of the corresponding first and second pins 3 and 4.
Specifically, as described above, each link 2 has a uniform hardness as a whole, and the whole including the peripheral edges 15 and 16 of the through holes 9 and 10 is a low hardness portion. The hardness of each link 2 is set to 48, for example, as Rockwell hardness HRC. Thus, the hardness of each link 2 is compared with the lower one of the corresponding surfaces 11 and 13 of the first and second pins 3 and 4 (the surface 13 of the second pin 4). The Rockwell hardness HRC is lowered by 5.

The hardness of each link 2 may be lower by less than 5 (excluding 0) in Rockwell hardness HRC or lower than 5 as compared with the hardness of the corresponding second pin 4. .
As described above, according to the present embodiment, each second pin 4 is superior in toughness as compared with the corresponding surface 11 of the first pin 3 and exhibits a buffering action to cope with it. The impact received from the first pin 3 or the like can be absorbed. In addition, when the first pin 3 bends in contact with the sheave surface with a strong pressure, the corresponding second pin 4 can follow and bend. Thereby, each 2nd pin 4 can be given sufficient intensity | strength, and it becomes possible to reduce in size (thinning), ensuring practically sufficient durability of each 2nd pin 4. FIG. . As a result, the chain 1 can be reduced in size while ensuring practically sufficient durability.

Further, since the hardness of each second pin 4 is 5 lower than the corresponding hardness of the surface 11 of the first pin 3 by Rockwell hardness HRC, the hardness of the surface 11 of the first pin 3 is reduced. Compared with toughness, the toughness of the second pin 4 can be made extremely excellent. As a result, the buffering action of each second pin 4 can be made extremely excellent, and further durability can be secured.
Further, for example, when the chain 1 is manufactured, when the first and second pins 3, 4 are inserted through the corresponding through holes 9, 10 of the corresponding link 2, the peripheral edges 15, 16 can prevent damage to the surfaces 11 and 13 of the corresponding first and second pins 3 and 4. As a result, the strength of the first and second pins 3 and 4 can be reliably maintained, and the durability can be further improved.

Further, since the hardness of each link 2 is set to 5 lower by the Rockwell hardness HRC than the hardness of the surface 13 of the corresponding second pin 4, the peripheral edges 15, 16 of the respective through holes 9, 10 are The hardness is sufficiently lowered, and it is possible to more reliably prevent the corresponding surfaces 11 and 13 of the first and second pins 3 and 4 from being damaged.
Further, when each first pin 3 comes into contact with the sheave surface of the pulley to transmit power, the corresponding second pin 4 is brought into rolling contact with the first pin 3 to respond accordingly. The links 2 can be bent in the chain traveling direction X. At this time, with respect to the corresponding first and second pins 3, 4, the mutual rolling contact component is large and the sliding contact component is small, and each first pin 3 hardly rotates with respect to the sheave surface. It is possible to reduce friction loss and ensure high transmission efficiency.

  Further, the trajectory of the contact line T between the first and second pins 3 and 4 is substantially involute as viewed from the outside in the chain width direction W, whereby each first pin 3 As a result, the string 1 can be restrained from undergoing a string-like motion when the sheaves are sequentially bitten by the sheave surface. As a result, noise during driving of the chain can be sufficiently reduced, and it is suitable for a continuously variable transmission for automobiles that is strongly required to be quiet.

  In the above embodiment, each first pin 3 has been described as having a uniform hardness in the surface portion and the inner portion. However, the present invention is not limited to this, and as shown in FIG. 4, the surface portion and the inner portion. The hardness may be different. In this case, each first pin 3 has a surface portion 18 having substantially the same hardness as the surface 11 and having a predetermined depth from the surface 11, and an interior 17. The hardness of the surface portion 18 of each first pin 3 may be higher or lower than the hardness of the inner portion 17.

Moreover, in each said embodiment, although each 2nd pin 4 demonstrated as what has uniform hardness in a surface part and an inner part, it is not restricted to this, As shown in FIG. The hardness of the portions may be different. In this case, the second pin 4 has a surface portion 23 having substantially the same hardness as the surface 13 and having a predetermined depth from the surface 13, and an interior 19.
Each second pin 4 may be formed such that the surface portion 23 has a lower hardness than the inner portion 19, or the inner portion 19 may be formed so as to have a lower hardness than the surface portion 23. . In this case, at least the lower hardness of the surface portion 23 and the interior 19 is the low hardness portion. If the hardness of the surface portion 23 and the interior 19 is lower than the hardness of the surface 11 of the first pin 3, the surface portion 23 and the interior 19 have a function as a low hardness portion.

Further, in each of the above embodiments, each link 2 has been described as having a uniform hardness in the surface portion and the inner portion. However, the present invention is not limited to this, and as shown in FIG. 6, the hardness of the surface portion and the inner portion. May be different. In this case, each link 2 has a surface portion 22 having substantially the same hardness as the surface 20 and having a predetermined depth from the surface 20, and an interior 21.
Of the surface portion 22 of each link 2, the peripheral portion of each through hole 9, 10 corresponds to the peripheral portion 15, 16 (low hardness portion). The hardness of the surface portion 22 of each link 2 (the peripheral edges 15 and 16 of the through holes 9 and 10) may be higher or lower than the hardness of the inner portion 21. However, the hardness is made lower than the hardness of the surfaces 11 and 13 of the first and second pins 3 and 4.

Moreover, in each said embodiment, it may replace with each 1st pin 3, and may use the power transmission block which has a power transmission surface. Moreover, it is not necessary to provide a low hardness part in each link 2.
FIG. 7 is a perspective view schematically showing a main configuration of a so-called chain-type continuously variable transmission (hereinafter also simply referred to as a continuously variable transmission) according to an embodiment of the power transmission device of the present invention. Referring to FIG. 7, the continuously variable transmission according to the present embodiment is mounted on a vehicle such as an automobile, and has a drive pulley 60 made of metal (such as structural steel) as a first pulley. A driven pulley 70 made of metal (structural steel or the like) as a second pulley, and an endless chain 1 wound around these pulleys 60 and 70 are provided. In addition, the chain 1 in FIG. 7 shows a partial cross section for easy understanding.

  FIG. 8 is a partially enlarged sectional view of the drive pulley 60 (driven pulley 70) and the chain 1 of the chain type continuously variable transmission shown in FIG. Referring to FIGS. 7 and 8, drive pulley 60 is attached to an input shaft 61 that is connected to a vehicle drive source so as to be able to transmit power, and includes a fixed sheave 62 and a movable sheave 63. The fixed sheave 62 and the movable sheave 63 have a pair of opposing sheave surfaces 62a and 63a as power transmission targets. The sheave surfaces 62a and 63a include conical inclined surfaces. A groove is defined between the sheave surfaces 62a and 63a, and the chain 1 is held between the grooves 1 with a strong pressure.

  Further, a hydraulic actuator (not shown) for changing the groove width is connected to the movable sheave 63, and the movable sheave 63 is moved in the axial direction of the input shaft 61 (left and right direction in FIG. 8) at the time of shifting. By changing the width of the groove, the chain 1 is moved in the radial direction of the input shaft 61 (vertical direction in FIG. 8), and the winding radius (effective radius) of the chain 1 with respect to the input shaft 61 can be changed. It has become.

  On the other hand, the driven pulley 70 is attached to an output shaft 71 connected to a drive wheel (not shown) so as to be able to transmit power, and, like the drive pulley 60, forms a groove for sandwiching the chain 1 with a strong pressure. Therefore, a fixed sheave 72 and a movable sheave 73 having sheave surfaces 72a and 73a as power transmission targets are provided. A hydraulic actuator (not shown) is connected to the movable sheave 73 of the driven pulley 70 in the same manner as the movable sheave 63 of the drive pulley 60, and the groove width is changed by moving the movable sheave 73 during shifting. Thereby, the chain 1 is moved so that the winding radius (effective radius) of the chain 1 with respect to the output shaft 71 can be changed.

  In the continuously variable transmission according to the present embodiment configured as described above, for example, a continuously variable transmission can be performed as follows. That is, when the rotation of the output shaft 71 is decelerated, the groove width of the drive pulley 60 is increased by the movement of the movable sheave 63, and the power transmission surfaces 5, 6 at both ends of the first pin 3 of the chain 1 are conical. Under boundary lubrication toward the inner side of the sheave surfaces 62a and 63a (downward in FIG. 8) (a lubrication state in which a part of the contact surface is in direct contact with the microprojections and the remaining part is in contact with the lubricating oil film) The wrapping radius of the input shaft 61 of the chain 1 is reduced while making sliding contact. On the other hand, in the driven pulley 70, the groove width is reduced by the movement of the movable sheave 73, and the power transmission surfaces 5, 6 of the first pin 3 of the chain 1 are moved outwardly from the conical surface of the sheave surfaces 72a, 73a (FIG. 8). The winding radius of the output shaft 71 of the chain 1 is increased while making sliding contact under boundary lubrication conditions.

  On the contrary, when the rotation of the output shaft 71 is increased, the groove width of the drive pulley 60 is reduced by the movement of the movable sheave 63, and the power transmission surfaces 5, 6 of the first pin 3 of the chain 1 are conical. The wrapping radius of the chain 1 with respect to the input shaft 61 is increased while making sliding contact under boundary lubrication conditions toward the outer side of the sheave surfaces 62a and 63a. On the other hand, in the driven pulley 70, the groove width is increased by the movement of the movable sheave 73, and the power transmission surfaces 5 and 6 of the chain 1 are slid under boundary lubrication conditions toward the inner side of the conical sheave surfaces 72a and 73a. The winding radius with respect to the output shaft 71 of the chain 1 is reduced while making contact.

As described above, according to the present embodiment, it is possible to realize a power transmission device that is excellent in transmission efficiency, quietness, and durability and that is compact.
Note that the power transmission device of the present invention is not limited to a mode in which the groove widths of both the drive pulley 60 and the driven pulley 70 are changed, and only one of the groove widths is changed and the other is not changed. The aspect made into the width | variety may be sufficient. In the above description, the groove width is continuously (stepless) changed. However, the groove width may be changed stepwise or may be applied to other power transmission devices such as a fixed type (no shift). .

  The present invention is not limited to the contents of the above embodiment, and various modifications are possible.

FIG. 1 is a perspective view schematically showing a configuration of a main part of a power transmission chain for a chain type continuously variable transmission according to an embodiment of the power transmission chain of the present invention. It is a cross-sectional top view of the principal part of the chain shown in FIG. It is sectional drawing which follows the II-II line of FIG. It is a section side view of the 1st pin of other embodiments of the present invention. It is a section side view of the 2nd pin of further another embodiment of the present invention. It is a cross-sectional side view of the link of further another embodiment of this invention. 1 is a perspective view schematically showing a main part configuration of a so-called chain type continuously variable transmission according to an embodiment of a power transmission device of the present invention. FIG. 8 is a partially enlarged cross-sectional view of a drive pulley (driven pulley) and a chain of the chain type continuously variable transmission shown in FIG. 7.

Explanation of symbols

1 Chain (Power transmission chain)
2 links (low hardness part, 1st link, 2nd link)
3 First pin 4 Second pin (low hardness part)
9 Front through hole (through hole)
10 Rear through hole (through hole)
11 (first pin) surface 13 (second pin) surface 15 (front through hole) peripheral edge (low hardness portion)
16 Peripheral edge (low hardness part)
19 (second pin) inside (low hardness part)
22 (Link) surface part (low hardness part)
23 (second pin) surface part (low hardness part)
60 Drive pulley (first pulley)
70 Driven pulley (second pulley)
62a, 63a, 72a, 73a Sheave surface (power transmission target)
X Chain travel direction

Claims (4)

Power that includes a plurality of links arranged in the chain traveling direction, and in which the corresponding links are connected to each other using a first pin that engages with a power transmission target and a second pin that rolls and slides into contact with the first pin In the transmission chain,
Said at least one surface and interior of the second pin, made from a low hardness low hardness portion as compared with the first pin surface,
Each of the plurality of links has a through-hole through which the first and second pins are inserted, and the periphery of each through-hole has a low hardness compared to the hardness of the surface of the first and second pins. A power transmission chain characterized by comprising a hardness part.   2. The power transmission chain according to claim 1, wherein the hardness of the low hardness portion of the second pin is 5 or more lower in Rockwell hardness HRC than the hardness of the surface of the first pin. In Claim 1 or 2, the plurality of links include first and second links, and each of the links has a front through hole and a rear through hole arranged in front and rear in the chain traveling direction, respectively.
The first pin is press-fitted and fixed in the front through hole of the first link and is movably fitted into the rear through hole of the second link. The second pin is a front through hole of the first link. A power transmission chain, wherein the power transmission chain is movably fitted to the second link and is press-fitted and fixed in a rear through hole of the second link.   The first and second pulleys each having a pair of conical sheave surfaces facing each other, and wound around these pulleys and engaged with a sheave surface as a power transmission target to transmit power. A power transmission device comprising the power transmission chain according to 1, 2, or 3.

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