JP2012127378A - Power transmission chain and power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission chain which enables a countermeasure against chain breakage to be taken without using a chain breakage countermeasure member (frame body, for instance) of a separate part and thereby enables manufacturing cost to be cut sharply compared with a chain using a chain breakage countermeasure member of a separate part, and to provide a power transmission device using the chain.SOLUTION: A plurality of links 11, 21 are partially structured as shock absorbing links 21 which absorb a shock when the power transmission chain 1 is broken and collides with a housing 30. The shock absorbing links 21 have a radial outward projection 22 which projects outward in the chain radial direction from the outer peripheral surfaces of other links 11 and, when the chain 1 is broken, absorbs a shock by colliding with the housing 30 first.

Description

  The present invention relates to a power transmission chain, and more particularly to a power transmission chain suitable for a continuously variable transmission (CVT) such as an automobile and a power transmission device using the power transmission chain.

  As a power transmission chain, connect multiple links with front and rear insertion parts through which pins are inserted, and links aligned in the chain width direction so that the front insertion part of one link and the rear insertion part of the other link correspond to each other A plurality of first pins and a plurality of second pins arranged before and after, and the first pin and the second pin are in rolling contact with each other, whereby the links can be bent in the length direction; It is known that at least one end surface of at least one of the first pin and the second pin is in contact with a pulley and power is transmitted by frictional force.

  In this type of power transmission device, when the power transmission chain is broken, a part of the chain detached from the pulley may collide with the housing, and the housing may be damaged. Therefore, it is preferable to provide the power transmission chain with a structure for preventing chain breakage as a fail-safe mechanism.

  Japanese Patent Application Laid-Open No. H10-228561 discloses a structure for preventing chain breakage by using a frame surrounding all links arranged in the width direction of the chain.

U.S. Pat. No. 4,618,338

  The frame used in the above-mentioned Patent Document 1 has a shape (member) different from that of the link, and using this increases the labor for manufacturing and the labor for assembly. Then, there was a problem that the manufacturing cost was high.

  The object of the present invention is to make it possible to take measures against chain breakage without using a separate part chain breakage countermeasure member (for example, a frame), thereby producing a chain breakage countermeasure member that is a separate part. An object of the present invention is to provide a power transmission chain and a power transmission device that can greatly reduce the cost.

  The power transmission chain according to the present invention includes a plurality of links having front and rear insertion portions through which pins are inserted, and links arranged in the chain width direction so that a front insertion portion of one link and a rear insertion portion of another link correspond to each other. A plurality of first pins and a plurality of second pins arranged before and after connecting each other are provided, and the first pin and the second pin are relatively rolled and brought into contact with each other, whereby the links can be bent in the length direction. In the power transmission chain in which at least one end face of the first pin and the second pin is in contact with the pulley and the power is transmitted by the frictional force, a part of the plurality of links is broken by the power transmission chain The shock-absorbing link absorbs the impact when it collides with the housing, and the shock-absorbing link protrudes outward in the chain radial direction from the outer peripheral surface of the standard link. It is characterized in that impinge upon previously during down break into the housing and has a radially outwardly projecting portion to absorb the impact.

  According to the power transmission chain of the present invention, when the power transmission chain breaks, a part of the chain that is detached from the pulley may collide with the housing. The radially outward projection first collides with the housing, and the radially outward projection is deformed to absorb the impact. Therefore, damage to the housing can be prevented.

  For example, the shock absorbing link has a shape in which only the outer portion in the chain radial direction is enlarged with reference to a standard link. Then, a part of the standard links is replaced with the shock absorbing links on the basis of all the standard links. The standard links are preferably of two types: short links with a relatively short pitch length and long links with a relatively long pitch length. In this case, the impact of a short link with a relatively short pitch length Two types are used: an absorbing link and a long link impact absorbing link having a relatively long pitch length.

  The shock absorbing link has a structure for preventing chain breakage that can be replaced with a standard link. By using this link, the number of parts increases, but the total number of parts does not increase. Further, the effort for manufacturing and assembling the shock absorbing link is almost the same as that for standard link manufacturing and conventional assembly, and an increase in manufacturing cost can be suppressed. Therefore, the manufacturing cost can be greatly reduced as compared with a structure using a separate part frame as a configuration for countermeasures against chain breakage.

  The protrusion amount of the radially outward protrusion of the shock absorbing link is set corresponding to the distance between the power transmission chain and the housing. The amount of protrusion of the radially outward projection of the shock absorbing link does not have to be the same.If the inner diameter of the housing varies depending on the position in the chain width direction, the amount of protrusion varies depending on the position in the chain width direction. Good.

  It is preferable that the radially outward projecting portion of the shock absorbing link is bent so as to cover the outer periphery of the power transmission chain. If it does in this way, the area of the part which collides will increase and the impact absorption effect will become still higher. Bending process increases the manufacturing process of the shock absorbing link by one process, but the manufacturing cost can be greatly reduced compared to using a separate frame for the chain breakage countermeasure. .

  In the power transmission chain according to the present invention, at least one of the first pin and the second pin comes into contact with the pulley to transmit power by frictional force. In a chain in which one of the pins contacts the pulley, one of the first pin and the second pin is a pin that contacts the pulley when the chain is used in a continuously variable transmission ( In the following, the pin is referred to as “first pin” or “pin”, and the other is referred to as the pin that does not contact the pulley (interpiece or strip). "Peace").

  For example, the first pin and the second pin are formed in a required curved surface so that one of the rolling contact surfaces is a flat surface and the other rolling contact surface is relatively rolling and movable. Moreover, you may make it a rolling contact surface form a required curved surface for the 1st pin and the 2nd pin. In any case, two types of rolling contact surface shapes of each pin (for example, those having a relatively large curvature and those having a relatively small curvature) are formed, so that the locus of the rolling contact movement is different. There may be two types of pin pairs. The locus of the contact position between the first pin and the second pin is, for example, an involute curve.

  In such a power transmission chain, the number of links arranged in the chain width direction is not all the same, but the number of links in each link row is made large and small, for example, the number of links is 2n (n: natural number) Two 2n layer link rows (eight as an example) and one 2n + 1 layer link row with 2n + 1 links (9 as an example) are one unit (link unit), and this link unit is moved in the chain traveling direction. A chain is configured by arranging the required number.

  The shock absorbing links are, for example, arranged on the outermost side (both sides) of the 2n + 1 layer link row, or arranged on the outermost side (both sides) of each link row. The link to be used as the shock absorbing link is not particularly limited, and it may be a place other than the outermost side, and may be provided only on one side.

  The shock absorbing link is preferably 30% or less (4% or more) of all the links. For example, in the case of a link unit of 8-8-9 rows, the case where it is provided only on one side of the 9th layer link row is 1 / (8 + 8 + 9) = 4%, and the case where it is provided on both sides of all link rows is (2 + 2 + 2). ) / (8 + 8 + 9) = 24%. If the impact absorbing link exceeds 30%, the impact absorbing effect does not increase and the weight (cost) increases. The portion that collides with the housing when the power transmission chain breaks includes a plurality of link rows, and even if shock absorbing links are provided on every other or every other link row, the required impact is achieved. Absorption effect can be obtained.

  In this specification, one end side in the length direction of the link is front and the other end side is rear, but this front and rear are for convenience, and the length direction of the link always coincides with the front and rear direction. It doesn't mean that.

  In the above power transmission chain, one of the pins (interpiece) is shorter than the other pin (pin), the end surface of the longer pin contacts the conical sheave surface of the pulley of the continuously variable transmission, It is preferable that power is transmitted by the frictional force due to this contact. Each pulley includes a fixed sheave having a conical sheave surface and a movable sheave having a conical sheave surface facing the sheave surface of the fixed sheave. The chain is sandwiched between the sheave surfaces of both sheaves, and the movable sheave. Is moved by a hydraulic actuator, the distance between sheave surfaces of the continuously variable transmission, that is, the wrapping radius of the chain is changed, and a continuously variable transmission can be performed with a smooth movement.

  The power transmission device according to the present invention includes a first pulley having a conical sheave surface, a second pulley having a conical sheave surface, and power transmission spanned between the first and second pulleys. And a power transmission chain as described in any of the above.

  This power transmission device is suitable for use as a continuously variable transmission such as an automobile.

  According to the power transmission chain and the power transmission device of the present invention, a part of the plurality of links is a shock absorbing link that absorbs a shock when the power transmission chain breaks and collides with the housing. Since the absorption link has a radially outward projection that protrudes radially outward of the chain from the outer peripheral surface of the standard link and impacts the shock by colliding with the housing first when the power transmission chain breaks, When the power transmission chain breaks and a part of the chain detached from the pulley collides with the housing, the radially outward projection of the shock absorbing link first collides with the housing, and the radially outward projection is deformed. By absorbing the impact, damage to the housing can be prevented.

FIG. 1 is a plan view showing a part of one embodiment of a power transmission chain according to the present invention. FIG. 2 is an enlarged side view of the standard link and pin. FIG. 3 is an enlarged side view of the shock absorbing link and pin of the first embodiment. FIG. 4 is a front view showing a state in which the power transmission chain of the first embodiment is attached to a pulley. FIG. 5 is a front view showing a state in which the power transmission chain of the second embodiment is attached to a pulley.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the top and bottom refer to the top and bottom of FIG.

  FIG. 1 shows a part of a power transmission chain according to the present invention. The power transmission chain (1) has front and rear insertion portions (12) and (13) provided at predetermined intervals in the chain length direction. A plurality of links (11) (21) and a plurality of pins (first pins) (14) and interpieces (first ones) linking the links (11) (21) arranged in the chain width direction so as to be bendable in the length direction 2 pins) (15). The interpiece (15) is made shorter than the pin (14), and both are opposed to each other with the interpiece (15) disposed on the front side and the pin (14) disposed on the rear side.

  In the chain (1), three link rows composed of a plurality of links having the same phase in the width direction are arranged in the traveling direction (front-rear direction) to form one link unit, and the link unit composed of the three rows of link rows is the traveling direction. Are connected to each other. In this embodiment, one link unit includes a link row having nine links and two link rows having eight links.

  Of the plurality of links (11) and (21), the link (21) on the outermost side (both sides) of one link unit is an impact absorbing link for a fail-safe mechanism to be described later.

  The links other than the shock absorbing link (21) (sometimes referred to as “standard links”) (11) have the same shape as the conventional one, and as shown in FIG. 2, the front insertion portion (12 ) Consists of a pin movable part (16) to which the pin (14) is movably fitted and an interpiece fixing part (17) to which the interpiece (15) is fixed, and the rear insertion part (13) is a pin ( The pin fixing portion (18) to which 14) is fixed and the interpiece movable portion (19) to which the interpiece (15) is movably fitted.

  As shown in FIG. 3, the shock absorbing link (21) is obtained by adding a radially outward projection (22) to a standard link (the outer peripheral surface of which is indicated by (11a)). That is, the shock absorbing link (21) has front and rear insertion portions (12) and (13) having the same shape as the standard link (11) (the front and rear of the front and rear insertion portions (12) and (13), The lower part has the same shape), and has a radially outward projecting part (22) projecting upward (outward in the radial direction of the chain).

  Each pin (14) is wider in the front-rear direction than the interpiece (15), and the upper and lower edges of the interpiece (15) have protruding edges (15a) extending to the respective pins (14) side. ) (15b).

  When connecting the links (11) (21) arranged in the chain width direction, the front insertion part (12) of one link (11) (21) and the rear insertion part (13) of the other links (11) (21) ) And the links (11) and (21) are overlapped so that the pin (14) is fixed to the rear insertion part (13) of one link (11) (21) and the other link (11) (21) is movably fitted to the front insertion part (12), and the interpiece (15) is movably fitted to the rear insertion part (13) of one link (11) (21) and the other It is fixed to the front insertion part (12) of the links (11) (21). Then, the pin (14) and the interpiece (15) are relatively rolled and brought into contact with each other, whereby the links (11) and (21) can be bent in the length direction (front-rear direction).

  At the boundary between the pin fixing part (18) of the link (11) (21) and the interpiece movable part (19), the upper and lower concave arcuate guide parts (19a) (19b) of the interpiece movable part (19) Are provided with upper and lower convex arc-shaped holding portions (18a) and (18b) for holding the pin (14) fixed to the pin fixing portion (18). Similarly, at the boundary between the interpiece fixing part (17) and the pin movable part (16), the upper and lower concave arcuate guide parts (16a) and (16b) of the pin movable part (16) are connected to the interpiece fixed part. Upper and lower convex arc-shaped holding portions (17a) and (17b) for holding the interpiece (15) fixed to the portion (17) are provided.

  The locus of the contact position between the pin (14) and the interpiece (15) with respect to the pin (14) is an involute of the circle, and in this embodiment, the rolling contact surface (14a) of the pin (14) Is an involute curve having a base circle of radius Rb and center M in the cross section, and the rolling contact surface (15c) of the interpiece (15) is a flat surface (the cross-sectional shape is a straight line). As a result, when each link (11) (21) moves from the straight region to the curved region of the chain (1) or from the curved region to the straight region, the pin (14) is fixed at the front insertion portion (12). The rolling contact surface (14a) is in contact with the rolling contact surface (15c) of the interpiece (15) while the rolling contact surface (15a) is in contact (including some sliding contact) with respect to the interpiece (15) in the state. In the rear insertion portion (13), the rolling contact surface (15c) is connected to the pin (14) with respect to the pin (14) in a state where the interpiece (15) is fixed in the interpiece movable portion (19). It moves while rolling (including some sliding contact) on the rolling contact surface (14a). 2 and 3, the portions indicated by reference signs A and B are lines (points in the cross section) where the pin (14) and the interpiece (15) are in contact with each other in the straight portion of the chain (1). , AB is the pitch.

  FIG. 4 shows a power transmission device in which the power transmission chain (1) is attached to a V-type pulley type CVT. In the power transmission device, as shown in FIG. 4, a pulley having a pulley shaft (2e) ( 2) The end face of the pin (14) is not in contact with the pulley (2 ) Contact the conical sheave surfaces (2c) and (2d), and power is transmitted by the frictional force generated by the contact.

  When the movable sheave (2b) of the drive pulley (2) at the position indicated by the solid line in FIG. 4 is moved toward and away from the fixed sheave (2a), the winding diameter of the drive pulley (2) is as shown in FIG. As indicated by the chain line, it is large when approaching and small when separated. In the driven pulley, although not shown, when the movable sheave moves in the opposite direction to the movable sheave (2b) of the drive pulley (2) and the winding diameter of the drive pulley (2) increases, the driven pulley is wound. When the diameter is reduced and the winding diameter of the drive pulley (2) is reduced, the winding diameter of the driven pulley is increased. As a result, a U / D (underdrive) state in which the winding diameter of the drive pulley (2) is minimum and the driving pulley is maximum is obtained, and the winding diameter of the drive pulley (2) is small. An O / D (overdrive) state in which the driven pulley has a minimum winding diameter can be obtained.

  In FIG. 4, when the power transmission chain (1) is broken, a part of the chain detached from the pulley (2) collides with the housing (30), and the housing (30) may be damaged. Therefore, it is preferable to provide the power transmission chain (1) with a structure for preventing chain breakage as a fail-safe mechanism. The shock absorbing link (21) is for that purpose.When the power transmission chain (1) is broken, the radially outward projecting portion (22) of the shock absorbing link (21) is the housing (30) first. And the radially outward projecting portion (22) is deformed to absorb the impact when it collides with the housing (30). Therefore, even when the power transmission chain (1) is broken, the housing (30) is not damaged accordingly.

  The shock absorbing link (21) has a structure for preventing chain breakage that can be replaced with the standard link (11). By using this, the number of parts increases, but the total number of parts does not increase. Further, the effort for manufacturing and assembling the shock absorbing link (21) is almost the same as that for manufacturing the standard link (11) and the conventional assembly, and an increase in manufacturing cost can be suppressed. Therefore, the manufacturing cost can be greatly reduced as compared with a structure using a separate part frame as a configuration for countermeasures against chain breakage.

  The shape of the shock absorbing link is not limited to that shown in FIG. 3 and FIG. 4 above, and the impact when it collides with the housing (30) due to the deformation of the radially outward projecting portion (22). Can be appropriately changed so as to be absorbed.

  For example, as shown in FIG. 5, the radially outward projecting portion (24) of the shock absorbing link (23) is bent so as to be L-shaped so as to cover the outer periphery of the power transmission chain (1). To be made. By doing so, the area of the colliding part is increased (the area of the bent part> the area corresponding to the link thickness), and the impact absorbing effect is further enhanced. Further, by appropriately changing the radial length of the L-shaped radially outward projecting portion (24) and the length of the bent portion, it can be made an appropriate shape according to the housing (30), Damage to the housing (30) can be prevented more reliably.

  The shock absorbing link (23) shown in FIG. 5 requires a bending process compared to the shock absorbing link (21) shown in FIG. 3 and FIG. Although it will increase, the manufacturing cost can be greatly reduced when compared with the structure using a separate frame as a structure for countermeasures against chain breakage.

  In the above, the shock absorbing links (21) and (23) need not be arranged on the outermost side of one link unit, and may be arranged at other positions depending on the shape of the housing (30). The number can be appropriately changed according to the degree of damage (test result) of the housing (30). However, if the number of shock absorbing links (21) (23) exceeds 30% of the total links (11) (21) (23), the shock absorbing effect will not increase and the power transmission chain (1) Since the weight (cost) increases, it is preferable that the shock absorbing links (21) and (23) be 30% or less of all the links (11), (21), and (23).

  In the above power transmission chain (1), polygonal vibration is caused by repeated vertical movement of the pin, which causes noise, but the pin (14) and the interpiece (15) are relatively rolled and moved in contact. In addition, since the locus of the contact position between the pin (14) and the interpiece (15) with respect to the pin (14) is an involute of the circle, both the contact surfaces of the pin and the interpiece are arcuate surfaces. Compared to the case, vibration can be reduced and noise can be reduced.

  When used in the CVT, the pin (14) and the interpiece (15) are guided by the movable parts (16) and (19) as described above to move in rolling contact with the pulley (2). The pin (14) hardly rotates with respect to the sheave surfaces (2c) and (2d), the friction loss is reduced, and a high power transmission rate is secured.

  Although not shown in the drawings, from the viewpoint of noise reduction, the standard link (11) is classified into two types, a short link having a relatively short pitch length and a long link having a relatively long pitch length, and these are random. It is preferable to arrange | position. In this case, there are two types of shock absorbing links (21) and (23): a short link shock absorbing link having a relatively short pitch length and a long link shock absorbing link having a relatively long pitch length. used.

(1) Power transmission chain
(2) Pulley
(2a) Fixed sheave
(2b) Movable sheave
(2c) (2d) Conical sheave surface
(11) Standard link
(14) Pin (1st pin)
(15) Interpiece (2nd pin)
(21) (23) Shock absorbing link
(22) (24) Radially outward projection
(30) Housing

Claims (4)

A plurality of links having front and rear insertion portions through which pins are inserted, and a plurality of links arranged before and after connecting links aligned in the chain width direction so that a front insertion portion of one link and a rear insertion portion of another link correspond to each other. The first pin and the plurality of second pins are provided, and the first pin and the second pin are relatively in rolling contact with each other, whereby the links can be bent in the longitudinal direction. In a power transmission chain in which at least one end surface of two pins is in contact with a pulley and power is transmitted by frictional force,
Some of the links are used as shock absorbing links that absorb shocks when the power transmission chain breaks and collides with the housing. A power transmission chain having a radially outward projection that projects outward in the radial direction of the chain and absorbs an impact by colliding with the housing first when the power transmission chain is broken.   The power transmission chain according to claim 1, wherein the radially outward projecting portion of the shock absorbing link is bent so as to cover the outer periphery of the power transmission chain.   The power transmission chain according to claim 1 or 2, wherein the shock absorbing link is 30% or less of all the links.   A power transmission chain comprising: a first pulley having a conical surface sheave surface; a second pulley having a conical surface sheave surface; and a power transmission chain spanned between the first and second pulleys. A power transmission device according to any one of claims 1 to 3.

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