JP2015150569A - Manufacturing method for power transmission chain - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for giving a proper residual stress to links in a pretension process.SOLUTION: A power transmission chain 1 contains a plurality of links 2 arranged in a direction of chain travel X and a plurality of coupling members 3 that couple the links 2 with one another. A manufacturing method for manufacturing the power transmission chain 1 comprises a pretension process for giving a pretension force to the power transmission chain 1. In the pretension process, a pretension force is given to the power transmission chain 1, with a higher winding radius R than a minimum winding radius during an actual use, so that a higher stress than a stress as a maximum tension during the actual use acts with the minimum winding radius during the actual use may develop in the links 2.

Description

  The present invention relates to a method for manufacturing a power transmission chain.

With a chain in which a plurality of links are connected by a joint member wound between a pair of pulleys, the axes of the pair of pulleys are pulled apart from each other, so that the nominal tensile force during operation (equivalent to the maximum tensile force generated during actual use) There has been proposed a pretension method for applying a larger tensile force (see, for example, Patent Document 1).
By the tension, the link is plastically deformed, a residual compressive stress is applied to the inside of the link, and the fatigue durability performance is improved.

Japanese translation of PCT publication No. 2003-5155076

Usually, at the time of pre-tensioning, the winding radius of the chain around the pulley is made smaller than the minimum winding radius in actual use. For this reason, as the residual stress obtained in the link after pre-tensioning, the residual stress in the first portion that becomes the outside of the bend when bent is larger than the residual stress in the second portion that becomes the inside of the bend when bent.
When an appropriate amount of residual stress is applied to the second portion, the residual stress applied to the first portion is greater than the appropriate value. For this reason, at the time of pre-tensioning, there is a possibility that the link length increases, the total length of the chain deviates from the standard, the chain is broken, and the like may cause problems. On the other hand, when an appropriate residual stress is applied to the first portion, the residual stress applied to the second portion is smaller than an appropriate value.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method of manufacturing a power transmission chain that can apply an appropriate residual stress to a link without causing any problems in the chain in the pre-tensioning process.

  In order to achieve the object, the invention of claim 1 is characterized in that a plurality of links (2) arranged in a chain traveling direction (X) and a chain width direction (W) orthogonal to the chain traveling direction extend the links to each other. Including a plurality of connecting members (3) to be connected, and a pretensioning step of applying pretension to the power transmission chain (1) wound between the pair of pulleys (31, 32) of the continuously variable transmission (30). A power transmission chain manufacturing method, wherein, in the pre-tensioning step, the minimum winding radius in actual use is greater than the minimum winding radius (Rmin) in actual use. A method of manufacturing a power transmission chain that provides pre-tension to the power transmission chain is provided so that a stress higher than the stress when the maximum tension in actual use is applied is generated in the link.

In addition, although the alphanumeric character in a parenthesis represents the corresponding component etc. in embodiment mentioned later, this does not mean that this invention should be limited to those embodiment as a matter of course. The same applies hereinafter.
According to a second aspect of the present invention, each link includes a through hole (4, 5) having a fixing portion (9, 10) to which the connecting member is fixed, and the fixing portion is outside of the bending when the chain is bent. And a first press-fit portion (31, 21) and a second press-fit portion (32, 22) that are respectively disposed on the inside and press-fit the connecting member, and in the pre-tensioning step, the stress of the second press-fit portion (Σ32, σ22) may be equal to or greater than or equal to the stress (σ31, σ21) of the first press-fit portion.

  As in claim 3, each link includes, as the through hole, a front through hole (4) and a rear through hole (5) arranged in the front-rear direction of the chain traveling direction, and a corresponding connecting member corresponding to each through hole. Each of the connecting members includes a pin (6) and a piece (7) that are in rolling contact with each other at a contact portion (A, B) that is displaced with bending between the links, and the rear through-hole is A pin fixing portion (10) as the fixing portion to which the pin is fixed by press-fitting, and a piece movable portion (11) through which the piece is movably inserted, and the front through-hole includes the pin A pin movable part (8) through which the piece is movably inserted, and a piece fixing part (9) as the fixing part to which the piece is fixed. 2 Stress (σ22) of the press-fitted part (22) The stress (σ21) of the first press-fit portion (21) of the fixed portion is equal to or greater than or equal to (σ22 ≧ σ21), and the stress (σ32) of the second press-fit portion (32) of the piece fixed portion is The stress (σ31) of the first press-fit portion (31) of the piece fixing portion may be equal to or greater than (σ32 ≧ σ31).

  According to the first aspect of the present invention, in the pre-tensioning step, a pre-tension is applied to the power transmission chain by increasing the distance between the centers of the pair of pulleys with a winding radius larger than the minimum winding radius in actual use. . As a result, in the link, the residual stress of the portion that becomes the outside of the bend when bent and the residual stress of the portion that becomes the inside of the bend when bent can be properly distributed. An appropriate residual stress can be obtained for the entire link without causing such problems as the above. As a result, a power transmission chain with excellent durability can be obtained.

  According to the second aspect of the present invention, in the pre-tensioning step, the second press-fitting portion is provided in the fixing portion of the through hole of the link in a state where the winding radius of the pulley is larger than the minimum winding radius in actual use. It should be equal to or equal to or greater than the stress of one press-fit part. As a result, in the pre-tensioning process, the stress of the first press-fit portion and the stress of the second press-fit portion can be appropriately distributed without causing a problem in the power transmission chain.

  According to the invention of claim 3, in the pre-tensioning step, the second press-fitting portion of the pin fixing portion is stressed in the first press-fitting portion in a state in which the winding radius of the pulley is larger than the minimum winding radius in actual use. And the second press-fit portion of the piece fixing portion is equal to or equal to or greater than the stress of the first press-fit portion. As a result, in the pre-tensioning process, the stress of the first press-fit portion and the stress of the second press-fit portion can be appropriately distributed in each of the pin fixing portion and the piece fixing portion without causing a problem in the power transmission chain. .

It is a top view which shows a part of power transmission chain with which the pre-tension method of the power transmission chain by this invention is applied. It is an enlarged side view of a link. It is a schematic side view of a continuously variable transmission. It is a front view which shows the state in which the power transmission chain was attached to the continuously variable transmission. It is a typical side view of a pretension applying device.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a part of a power transmission chain to which a pretension method according to an embodiment of the present invention is applied. The power transmission chain 1 (hereinafter also simply referred to as the chain 1) includes a plurality of links 2 arranged in the chain traveling direction X and links extending in the chain width direction W perpendicular to the chain traveling direction X and arranged in the chain width direction W. And a plurality of connecting members 3 that connect the two members so that they can be bent in the length direction.

  Each link 2 has a front through-hole 4 and a rear through-hole 5 provided at a predetermined interval in the chain traveling direction X. The connecting member 3 is inserted into each of the through holes 4 and 5. Each connecting member 3 includes a pin 6 as a first power transmission member and a piece 7 as a second power transmission member. The front through-hole 4 and the rear through-hole 5 may have an integrated shape so as to communicate with each other.

  In the chain 1, three link rows composed of a plurality of links 2 having the same phase in the width direction are arranged in the chain traveling direction X (front-rear direction) to form one link unit, and the link unit composed of the three link rows travels. A plurality are connected in the direction. In this embodiment, one link unit includes a link row having nine links and two link rows having eight links.

As shown in FIG. 2, the front through-hole 4 of the link 2 includes a pin movable part 8 through which the pin 6 is movably inserted and a piece fixing part 9 to which the piece 7 is fixed. In the front through hole 4, the piece fixing portion 9 is disposed on the side of the pin movable portion 8 in the chain traveling direction X.
The rear through-hole 5 includes a pin fixing portion 10 to which the pin 6 is fixed and a piece movable portion 11 into which the piece 7 is movably inserted. In the rear through-hole 5, the piece movable portion 11 is disposed on the chain moving direction X side of the pin fixing portion 10.

The pin fixing portion 10 of the rear through-hole 5 includes a first press-fit portion 21 and a second press-fit portion 22 that are respectively disposed on the outer side and the inner side of the bend when the chain is bent, and into which the pin 6 is press-fitted. Moreover, the piece fixing | fixed part 9 of the front through-hole 4 is respectively arrange | positioned at the outer side and inner side of the bending at the time of chain bending, and contains the 1st press-fit part 31 and the 2nd press-fit part 32 which press-fitted the piece 7.
Each pin 6 is wider in width in the chain traveling direction X than the piece 7. Corresponding to the upper and lower edges of each piece 7 (upper and lower in FIG. 2, the side that is the outside of the bend when the chain is bent corresponds to the upper side, and the side that is the inside of the bend when the chain is bent corresponds to the lower side). Protruding edge portions 12 and 13 extending toward the pin 6 to be provided are provided. However, the shape of the pin 6 and the piece 7 is not limited to the above-mentioned form.

  The pin 6 and the corresponding piece 7 of each connecting member 3 include opposing portions 6a and 7a that face each other. A part of each opposing part 6a and 7a comprises the rolling sliding contact surfaces 6b and 7b, respectively. Each piece 7 is arranged closer to the chain traveling direction X side than the corresponding pin 6. The rolling sliding contact surfaces 6b and 7b of the respective connecting members 3 are in rolling contact with each other at the contact portions A and B that are displaced in accordance with the change in the bending angle between the links 2. In the straight part of the chain, the distance between AB is the pitch.

  When connecting the links 2 arranged in the chain width direction, the links 2 are overlapped so that the front insertion hole 3 of one link 2 corresponds to the rear through hole 5 of the other link 2. The pin 6 is fixed to the rear through hole 5 of one link 2 and is movably fitted to the front through hole 4 of the other link 2 so that the piece 7 can move to the rear through hole 5 of the one link 2. It is fitted and fixed to the front through hole 4 of the other link 2. Then, the pins 6 and the pieces 7 are relatively rolled and brought into contact with each other, whereby the links 2 can be bent in the length direction (front-rear direction).

In the front through-hole 4 of the link 2, the upper and lower sides (the outer side and the inner side of the bending when the chain is bent) holding the piece 7 fixed to the piece fixing part 9 are arranged at the boundary part between the pin movable part 8 and the piece fixing part 9. ) Convex arcuate holding portions 14a, 14a are provided. The holding portions 14 a and 14 b are connected to the upper and lower concave arc-shaped guide portions 15 a and 15 b of the pin movable portion 8, respectively.
In the rear through-hole 5 of the link 2, the upper and lower sides (the outer side and the inner side of the bending when the chain is bent) holding the pin 7 fixed to the pin fixing unit 10 at the boundary portion between the pin fixing unit 10 and the piece movable unit 11. ) Convex arc-shaped holding portions 16a and 16b. The holding parts 16a and 16a are connected to the upper and lower concave arc-shaped guide parts 17a and 17b of the piece movable part 11, respectively.

  The locus of the contact position between the pin 6 and the piece 7 with respect to the pin 6 is an involute of a circle. In this embodiment, the rolling sliding contact surface 6b of the pin 6 has an involute shape having a predetermined radius and a base circle in the cross section, and the rolling sliding contact surface 7b of the piece 7 is a flat surface (the cross sectional shape is a straight line). It is said that. In addition, the shape of the pin 6 and the piece 7 is not formed by a combination of an involute and a straight line, but may be formed by a combination of a curved line and a curved line, or a combination of a curved line and a straight line. Further, the pin 6 and the piece 7 may have the same shape.

  As a result, when each link 2 moves from the straight portion of the chain 1 to the curved portion or from the curved portion to the straight portion, the pin 6 rolls relative to the fixed piece 7 in the front through-hole 4. While the sliding contact surface 6b is in rolling contact with the rolling contact surface 7b of the piece 7, it moves in the pin movable portion 8. Further, in the post-insertion through 4, the piece 7 moves to the fixed pin 6 while the rolling sliding contact surface 7 b is in rolling contact with the rolling sliding contact surface 6 b of the pin 6. 11 is moved.

As shown in FIG. 3, the power transmission chain 1 is used by being wound between a pair of pulleys (a driving pulley 41 and a driven pulley 42) of the continuously variable transmission 40.
At this time, as shown in FIG. 4, the end surface of the pin 6 in a state where the end surface of the piece 7 does not contact the fixed sheave 44 of the drive pulley 41 having the pulley shaft 43 and the conical sheave surfaces 44 a and 45 a of the movable sheave 45. Contacts the conical sheave surfaces 44a and 45a of the drive pulley 41, and the power is transmitted by the frictional force generated by the contact.

As described above, the pin 6 and the piece 7 are guided by the movable parts 8 and 11 and are in rolling contact movement, so that the pin 6 hardly rotates with respect to the sheave surfaces 44a and 45a of the drive pulley 41. Friction loss is reduced and high power transmission rate is ensured.
When the movable sheave 45 of the drive pulley 41 located at the position indicated by the solid line is moved closer to or away from the fixed sheave 44, the winding radius of the chain 1 is large when approaching, as indicated by the chain line in FIG. It becomes smaller at the time of separation.

Although not illustrated in the driven pulley 42, when the movable sheave moves in the opposite direction to the movable sheave 45 of the driving pulley 41 and the winding radius of the driving pulley 41 increases, the winding radius of the driven pulley 42 decreases. Thus, when the winding radius of the driving pulley 41 is reduced, the winding radius of the driven pulley 42 is increased.
As a result, with reference to the state (initial value) where the gear ratio is 1: 1, as shown in FIG. 3, the driven pulley 41 has a minimum winding radius Rmin in actual use as shown in FIG. An underdrive state in which the winding radius of 42 is maximum is obtained. Although not shown, an overdrive state in which the winding radius of the driving pulley 41 is the maximum and the winding radius of the driven pulley 42 is the minimum is obtained.

In order to manufacture the power transmission chain 1, a necessary number of connecting members 3 (a set of pins 6 and pieces 7) are vertically held on a table, and then the links 2 are press-fitted one by one or several at a time. Thus, the link 2 and the connecting member 3 are combined to form an endless chain, and then a pretension is applied to the assembled chain 1 in a pretensioning step.
The upper and lower edge portions of the pin 6 are press-fitted into the first press-fit portion 21 and the second press-fit portion 22 of the pin fixing portion 10, respectively. Further, the upper and lower edge portions of the piece 7 are press-fitted into the first press-fit portion 31 and the second press-fit portion 32 of the piece fixing portion 9, respectively. The press-fitting allowance is, for example, 0.005 mm to 0.1 mm.

FIG. 5 shows a pretension applying device 50 used in a pretensioning process for applying pretension.
The pretension applying device 50 moves the shaft 52a of the movable pulley 52 with respect to the shaft 51a of the fixed pulley 51 and the fixed pulley 51 and the movable pulley 52 around which the endless chain 1 can be wound. And a servo cylinder 53 as a tension applying member for changing the distance L between the centers of the pulleys 51 and 52. The servo cylinder 53 is not limited to this and may be a cylinder.

Further, the pretension applying device 50 is provided at the tip of the servo rod 54a of the servo cylinder 53 and the servo rod 53a of the servo cylinder 53 that acts on the piston rod 53a as a tension control member for controlling the moving amount of the piston rod 53a of the servo cylinder 53. And a load cell 55 as a tension measuring member for measuring the load being applied.
The pretension applying device 50 includes a connecting rod 56 that connects the load cell 55 and the shaft 52 a of the movable pulley 52, and a pulley driving member (not shown) that rotates the fixed pulley 51 or the movable pulley 52. The winding radius of each pulley 51, 52 is fixed so as not to change during the pre-tensioning process.

  Specifically, the winding radius R of the movable pulley 52 and the fixed pulley 51 is larger than the minimum winding radius Rmin (see FIG. 3 corresponding to the winding radius of the drive pulley 41 in the underdrive state) in actual use. Has been. Of the winding radius of the driving pulley 41 in the underdrive state and the winding radius of the driven pulley 42 during overdrive, the smaller winding radius is the minimum winding radius Rmin in actual use. In the present embodiment, a description will be given based on a case where the winding radius of the drive pulley 41 in the underdrive state corresponds to the minimum winding radius Rmin in actual use.

While monitoring the load detected by the load cell 55, the servo driven by the servo motor 54 so that a higher stress is generated in the link 2 than the stress when the maximum tension in actual use is applied with the minimum winding radius in actual use. The center distance L between the pulleys 51 and 52 is increased by the cylinder 53.
In the pre-tensioning process, it is preferable that a load larger than the load corresponding to the elastic limit stress is applied to the link 2 after the link 2, the pin 6 and the piece 7 are assembled. Specifically, for example, the load applied during pre-tensioning is such that the elastic limit stress is, for example, 5% or more larger than that before pre-tensioning, and is, for example, 95% or less of the breaking strength of the link. It is preferably set.

  According to the present embodiment, in the pre-tensioning step, pre-tension is applied to the power transmission chain 1 with a winding radius R (R> Rmin) larger than the minimum winding radius Rmin during actual use. Thereby, in the link 2, the residual stress of the portion that is outside the bend when bent and the residual stress of the portion that is inside the bend when bent can be appropriately distributed. Appropriate residual stress can be obtained for the entire link 2 without causing problems such as excessive extension of the entire length. As a result, the power transmission chain 1 excellent in durability can be obtained.

  In the pre-tensioning process, in the state where the winding radius R of both the pulleys 51 and 52 is larger than the minimum winding radius Rmin in actual use, The stresses σ32 and σ22 of the two press-fit portions 32 and 22 are made equal to or greater than or equal to the stresses σ31 and σ21 of the corresponding first press-fit portions 31 and 21. As a result, in the pre-tensioning process, the stresses σ32 and σ22 of the second press-fit portions 32 and 22 and the stresses σ31 and σ21 of the first press-fit portions 31 and 21 corresponding to the second press-fit portions 32 and 22 are appropriately set without causing any trouble in the power transmission chain 1. Can be allocated.

  Specifically, in the pre-tensioning process, the stress σ22 of the second press-fit portion 22 of the pin fixing portion 10 in a state where the winding radius R of both the pulleys 51 and 52 is larger than the minimum winding radius Rmin during actual use. Is equal to or more than or equal to the stress σ21 of the first press-fit portion 21 of the pin fixing portion 10 (σ22 ≧ σ21, and the stress σ32 of the second press-fit portion 32 of the piece fixing portion 9 is The stress is equal to or greater than or equal to σ31 (σ32 ≧ σ31).

  As a result, the stress σ21 of the first press-fit portion 21 and the stress σ22 of the second press-fit portion 22 can be appropriately distributed in the pin fixing portion 10 without causing any trouble in the power transmission chain 1 in the pre-tensioning process. . Further, in the pre-tensioning step, the stress σ31 of the first press-fit portion 31 and the stress σ32 of the second press-fit portion 32 can be appropriately distributed in the piece fixing portion 9 without causing any trouble in the power transmission chain 1.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Power transmission chain, 2 ... Link, 3 ... Connecting member, 4 ... Front through-hole, 5 ... Rear through-hole, 6 ... Pin, 6a ... Opposing part, 6b ... Rolling sliding contact surface, 7 ... Piece, 7a ... Opposing part, 7b ... rolling sliding contact surface, 8 ... pin movable part, 9 ... piece fixing part, 10 ... pin fixing part, 11 ... piece movable part, 21 ... first press-fitting part, 22 ... second press-fitting part, 31 DESCRIPTION OF SYMBOLS 1st press-fit part, 32 ... 2nd press-fit part, 40 ... Continuously variable transmission, 41 ... Drive pulley, 42 ... Driven pulley, 44 ... Fixed sheave, 45 ... Movable sheave, 50 ... Pre-tensioning device, 51 ... Fixed Pulley, 52 ... movable pulley, 53 ... servo cylinder, 54 ... servo motor, 55 ... load cell, 56 ... connecting rod, L ... center distance, X ... chain travel direction, W ... chain width direction, σ21, σ31 ... Stress of 1 press-fit part, σ22, σ32 ... (second press-fit part) ) Stress, R ... winding radius, Rmin ... minimum winding radius at the time of actual use

Claims (3)

A plurality of links arranged in the chain traveling direction and a plurality of connecting members that extend in the chain width direction orthogonal to the chain traveling direction and connect the links to each other, and are wound around a pair of pulleys of the continuously variable transmission A power transmission chain manufacturing method including a pretensioning step of applying pretension to a power transmission chain,
In the pre-tensioning step, the stress is higher than the stress at the time when the maximum tension at the actual use is applied at the minimum wrapping radius at the actual use with the wrap radius larger than the minimum wrap radius at the actual use. A method of manufacturing a power transmission chain that provides pre-tension to the power transmission chain so that is generated in the link. In Claim 1, each said link contains a penetration hole which has a fixed part to which said connecting member is fixed,
The fixing portion includes a first press-fit portion and a second press-fit portion, which are arranged on the outer side and the inner side of the bend when the chain is bent, respectively, and press-fit the connecting member,
In the pre-tensioning step, the power transmission chain manufacturing method wherein the stress of the second press-fit portion is equal to or greater than the stress of the first press-fit portion. In claim 2, each of the links includes a front through hole and a rear through hole arranged in the front and rear of the chain traveling direction as the through hole,
A corresponding connecting member is inserted into each through hole,
Each of the connecting members includes a pin and a piece that are in rolling contact with each other at a contact portion that is displaced by bending between the links,
The rear through hole includes a pin fixing portion as the fixing portion where the pin is fixed by press fitting, and a piece movable portion through which the piece is movably inserted,
The front through-hole includes a piece fixing part as the fixing part to which the piece is fixed, and a pin movable part through which the pin is movably inserted,
In the pre-tensioning step, the stress of the second press-fit portion of the pin fixing portion is equal to or greater than or equal to the stress of the first press-fit portion of the pin fixing portion, and the second press-fit portion of the piece fixing portion The power transmission chain manufacturing method in which the stress is equal to or greater than the stress of the first press-fitting portion of the piece fixing portion.

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