JP2004190830A - Chain for power transmission and power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chain for power transmission having a wear resistance of such a degree that, even if the chain is used under high surface pressure an high torque conditions and boundary lubrication conditions, an abnormal wear does not occur. <P>SOLUTION: This chain for power transmission (chain for continuously variable transmission) 1 comprises a plurality of links 2 and a plurality of pins 3 connecting these links to each other. The chain 1 is used by stretching across first and second pulleys, and the end face of the pin 3 comes into slidable contact with the sheave surfaces of the first and second pulleys. Therefore, a hard film 6 is formed on the end face side uppermost surface of the pin 3 of the chain 1. In particular, a film containing diamond-like carbon is desirable as the hard film 6. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power transmission chain, such as a continuously variable transmission chain, and a power transmission device, such as a continuously variable transmission, employed in a vehicle or the like.
[0002]
[Prior art]
As a continuously variable transmission (CVT) of an automobile, for example, a drive pulley provided on an engine side, a driven pulley provided on a drive wheel side, and an endless chain bridged between the two. Some are provided with In this continuously variable transmission, large power transmission is performed by contact between the conical sheave surface of the drive pulley or driven pulley and the pin end surface of the chain by boundary lubrication, and the respective grooves of the drive pulley and driven pulley are formed. By continuously changing the width (distance between sheave surfaces), continuously variable transmission is possible.
[0003]
In such continuously variable transmissions, VDT (Van Doornes Transmissie) push type (push-type) belts are currently the mainstream. There is a problem that application to large vehicles is difficult.
On the other hand, research and development of pull type (pull type) is also underway, and a chain having a torque capacity of about 280 N · m has been put to practical use, but it is also difficult to apply it to medium and large vehicles. There is.
[0004]
Regardless of the push type or pull type, since it is necessary to enable continuously variable transmission and transmit power efficiently, the boundary lubrication state (part of the contact surface , The rest being in contact with the lubricating oil film) in contact with the sheave surface of the drive pulley or driven pulley. In detail, at the time of gear shifting, the power is transmitted by making sliding contact in the inward and outward directions of the sheave surface and making a slight sliding contact in the circumferential direction of the sheave surface, and power transmission is performed with a fixed transmission ratio. Sometimes it is installed in a state where power is transmitted by making a slight sliding contact in the circumferential direction of the sheave surface.
However, in such a contact in the boundary lubrication state, there is a portion where the pin end surface of the metal chain and the sheave surface are in direct metal contact with each other. ), There is a problem that abnormal wear occurs in use under. In order to solve this problem, it is conceivable to reduce the friction coefficient or the contact surface pressure. However, if these are small, slip (particularly macro slip) occurs, and power transmission is not performed efficiently. Occurs.
[0005]
Among these, for example, a link plate chain for a steplessly adjustable conical disc-shaped wrapping gear, the joints of which link the individual chain links formed by the plates In the form in which the members are configured as pairs of cradle members with mutually supporting rolling surfaces inserted in the notches of the plate, at least the end faces of the cradle members in operative contact with the conical disk are nitrogen-free. A link plate chain provided with an edge layer containing, for example, a carbonitrided layer has been proposed (for example, see Patent Document 1).
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-147542 (Claim 1, FIG. 1, FIG. 3)
[0007]
[Problems to be solved by the invention]
However, since the link plate chain described above has a carbonitrided layer at the contact surface with the pulley, the wear resistance has been improved to some extent. However, under the conditions of high surface pressure, high torque, and boundary lubrication, It is not enough to withstand use. As described above, in the continuously variable transmission as described above, whether it is a push type or a pull type, application to medium-sized and large-sized vehicles is an important issue. There has been a demand for the development of a technology that can stably transmit power at a predetermined transmission ratio over a long period of time even when used under lubricating conditions.
[0008]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a power transmission chain and a power transmission device having wear resistance that can withstand use under high surface pressure, high torque conditions and boundary lubrication conditions. And Further, it is another object of the present invention to provide a power transmission chain and a power transmission device having a high friction coefficient capable of efficiently transmitting power under high surface pressure, high torque conditions and boundary lubrication conditions.
[0009]
[Means for Solving the Problems]
A power transmission chain according to the present invention includes a plurality of links and a plurality of pins interconnecting the links, a first pulley having a conical sheave surface, and a second pulley having a conical sheave surface. A power transmission chain which is used by being bridged between the pulleys and which makes sliding contact between an end surface of the pin and a sheave surface of the first and second pulleys, wherein the pin is It has a hard coating on the outermost surface on the end face side (claim 1).
According to the above configuration, since the pin end surface that comes into contact with the sheave surface when the power transmission device is incorporated has a hard coating, the high surface pressure and high torque conditions (high surface pressure of 400 MPa or more, high torque of 300 Nm or more) and Even if the present invention is applied to a power transmission device used under boundary lubrication conditions, a device that does not cause abnormal wear for a long period of time can be provided.
Here, in the present invention, the “hard coating” refers to a coating having a Vickers hardness of 1000 (Hv) or more, preferably 1000 to 2000 (Hv).
[0010]
In the above power transmission chain, it is preferable that the hard coating is a coating containing diamond-like carbon. With this configuration, wear resistance is high enough that abnormal wear does not occur even when used under high surface pressure and high torque conditions and boundary lubrication conditions, and power is efficiently supplied under high surface pressure and high torque conditions and boundary lubrication conditions. Since it also has a high friction coefficient enough to transmit power, it is possible to provide a more suitable chain for power transmission used under high surface pressure, high torque conditions and boundary lubrication conditions.
Here, in the present invention, the “film containing diamond-like carbon” is a film containing diamond-like carbon. In view of providing a chain having both abrasion resistance and a high friction coefficient under high surface pressure, high torque conditions and boundary lubrication conditions, diamond-like carbon is contained as a main component (50% by weight or more). Preferably, it is a membrane.
[0011]
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 a first pulley having a conical sheave surface. A power transmission device comprising: a plurality of pins each having an end surface in sliding contact with a sheave surface of a pulley; and a chain having a plurality of links interconnected by the pins. A hard coating is provided on at least one of the surface and the outermost surface on the sheave surface side of the first and second pulleys (claim 3).
According to the above configuration, since the hard coating is provided on at least one of the outermost surface on the pin end surface side and the outermost surface on the sheave surface side, high surface pressure and high torque conditions and boundary lubrication conditions are satisfied. However, abnormal wear does not occur for a long period of time, so that power can be stably transmitted at a predetermined transmission ratio for a long period of time.
[0012]
In the above power transmission device, it is preferable that the hard film is a film containing diamond-like carbon (claim 4). With this configuration, wear resistance is high enough that abnormal wear does not occur even when used under high surface pressure and high torque conditions and boundary lubrication conditions, and power is efficiently supplied under high surface pressure and high torque conditions and boundary lubrication conditions. Since it also has a high friction coefficient enough to transmit power, power transmission can be performed at a predetermined transmission ratio more stably for a long period of time.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a continuously variable transmission chain (hereinafter simply referred to as a “chain”) as a power transmission chain and a continuously variable transmission as a power transmission device of the present invention will be described. First, a chain as a power transmission chain of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is a perspective view schematically showing a configuration of a main part of an embodiment of a chain as a power transmission chain of the present invention, and FIG. 2 is a cross-sectional view taken along line XX of FIG. The chain 1 according to the present embodiment is endless and includes a plurality of metal (bearing steel or the like) links 2 and a plurality of metal (bearing steel or the like) pins 3 for connecting the links 2 alternately. Be composed.
The link 2 has a rectangular parallelepiped shape, and is provided with two through-holes 4 for each one, so that two pins 3 can be pressed into each of the through-holes 4. The links 2 are arranged in parallel to the width direction of the chain 1 and are connected so that the through holes 4 are shifted by one every other row and can be bent in the longitudinal direction of the chain 1.
The pin 3 has a slanted end surface 5a, 5b, and a metal (bearing steel or the like) rod-shaped body 5 having a side surface along the inner peripheral surface of the through-hole 4, and the slant of the end surface 5a, 5b. And a hard coating 6 to be described later. The pin 3 is press-fit slidably in the circumferential direction with its side surface along the inner peripheral surface of the through hole 4 of the link 2. A solid lubricant such as molybdenum disulfide or fluorine is applied to the side surface of the pin 3 or the inner peripheral surface of the through hole 4 to reduce abrasion and sliding resistance. A concave portion for storing the lubricating oil may be formed by performing a roughening process. Further, the pins 3 may have a shape in which the end surfaces 5a and 5b are expanded so as not to fall off from the link 2.
[0015]
The hard film 6 is a film having a Vickers hardness of 1000 (Hv) or more, preferably about 1000 to 2000 (Hv). By having the hard coating 6 on the outermost surface on the end face side of the pin 3 as described above, even when applied to a continuously variable transmission used under conditions of high surface pressure, high torque and boundary lubrication, abnormalities occur for a long time. No wear occurs.
Specific examples of the hard coating 6 include a chemical vapor deposition film (CVD film) using titanium carbide (TiC), titanium nitride (TiN), alumina (Al ₂ O ₃ ), diamond, or the like; titanium nitride (TiN); (Ti), a physical vapor deposited film (PVD film) using diamond-like carbon (hereinafter, also referred to as “DLC”) or the like. Further, for example, a film made of a plurality of materials such as a tungsten-containing diamond-like carbon film (hereinafter, also referred to as “tungsten-containing DLC film”) may be used. Among them, a film containing DLC is preferable, and a film containing DLC as a main component (50% by weight or more) is particularly preferable. This is because DLC has a smaller friction coefficient difference under lubricating and non-lubricating conditions than titanium nitride or the like, and has a higher friction coefficient under a high surface pressure (400 MPa or more) lubrication condition than titanium nitride or chromium nitride. Under boundary lubrication conditions where the direct contact (non-lubricated part) and the part through the oil film (lubricated part) are mixed in the contact surface, even if the surface contact state fluctuates during operation, the friction coefficient is stable, This is because it is considered that highly efficient and stable power transmission can be performed. DLC also has the advantage that film formation is easy and inexpensive.
[0016]
The method of forming the hard film 6 will be specifically described below by taking a DLC film and a tungsten-containing DLC film as examples.
The DLC film (film composed of only DLC) as the hard film 6 is formed, for example, by vapor-depositing carbon on the end surfaces 5a and 5b in a vapor deposition chamber into which an introduction gas such as an argon gas or a hydrocarbon gas is introduced. (Sputtering method). The film formation conditions such as the pressure in the vapor deposition chamber and the discharge voltage are appropriately selected so as to form a film having a predetermined thickness having an amorphous structure in which a graphite (SP ² ) structure and a diamond (SP ³ ) structure coexist. . Further, it is preferable that masking is performed on a portion excluding the end surfaces 5a and 5b using a mask member so that carbon is not deposited.
In addition to the above sputtering method, other physical vapor deposition methods (PVD) such as an ion plating method by ion beam vapor deposition using benzene as a raw material gas, a chemical vapor deposition method (CVD), or thermal spraying such as plasma spraying using a plasma jet. The DLC film may be formed using a method. Further, the end faces 5a and 5b may be roughened by knurling or the like to increase the adhesion (adhesion strength) to the end faces 5a and 5b on which the DLC film is formed. Since the PVD such as the sputtering method is a film forming method using a physical mechanism, the PVD is not affected by the material of the base (the metal rod-shaped body 5). It is most suitable for forming a DLC film because it can easily ensure high adhesion to the DLC film.
[0017]
The tungsten-containing DLC film as the hard film 6 is formed, for example, by depositing tungsten carbide on the end faces 5a and 5b in a deposition chamber into which an introduction gas such as an argon gas or a hydrocarbon gas is introduced, or by introducing a hydrocarbon gas. It can be formed by vapor-depositing tungsten on the end faces 5a and 5b in the vapor deposition chamber (sputtering method). The film formation conditions such as the pressure in the vapor deposition chamber and the discharge voltage are appropriately selected so as to form a film having a predetermined thickness having an amorphous structure in which a graphite (SP ² ) structure and a diamond (SP ³ ) structure coexist. . In addition, it is preferable that masking is performed on portions other than the end surfaces 5a and 5b using a mask member. Such a tungsten-containing DLC film has a high adhesiveness (adhesion strength) to the end surfaces 5a and 5b, and thus has an advantage that peeling does not easily occur even if the end surfaces 5a and 5b are not roughened. . When a film is formed by a sputtering method using tungsten carbide as a target in an argon gas atmosphere, a tungsten carbide film is formed, and the tungsten carbide film is substantially the same as a diamond-like carbon film containing tungsten. And a film having high adhesion.
[0018]
It is preferable that the tungsten-containing DLC film is formed such that the tungsten component is contained more on the formation surface side than on the film surface side. That is, it is possible to further improve the adhesion by inclining the composition component of the tungsten-containing DLC film so that the tungsten component as a metal atom is more present on the end faces 5a and 5b side of the rod-shaped body 5 as a metal material. This is because a film having both abrasion resistance and a high friction coefficient can be obtained. Such a tungsten-containing DLC film in which the composition component is inclined can be formed by, for example, appropriately changing the amount of carbon-hydrogen gas or shielding the end faces 5a and 5b with a shutter during the film formation.
The tungsten-containing DLC film can be formed by using a physical vapor deposition method, a chemical vapor deposition method, or a thermal spraying method other than the sputtering method, similarly to the above-described DLC film.
[0019]
In the chain according to the present embodiment, the pin 3 is provided with the hard coating 6 directly on the end faces 5a and 5b of the metal rod 5 and the hard coating 6 on the outermost surface on the end face side of the pin 3. It has wear resistance enough to withstand use under high surface pressure, high torque conditions and boundary lubrication. In particular, when a DLC film is formed as the hard film 6, the hard film 6 has a high coefficient of friction in addition to the wear resistance. Further, when a tungsten-containing DLC film is formed as the hard film 6, it has both good wear resistance and a high coefficient of friction, and is more difficult to peel off than the DLC film.
[0020]
FIG. 3 is a cross-sectional view schematically showing another embodiment of the chain as the power transmission chain of the present invention. The chain 1 is configured such that a hard coating 6 is formed on an end face 5a, 5b of a metal rod 5 with a base film 7 interposed therebetween. The base film 7 is a film formed mainly for improving the adhesion of the hard film 6. When a DLC film is formed as the hard film 6 as the base film 7, a metal thin film made of an active transition metal such as chromium and titanium is preferable in addition to the tungsten-containing DLC film. When a tungsten-containing DLC film is formed as the hard film 6, a metal thin film made of an active transition metal such as chromium or titanium is preferable. With such a two-layer structure, the hard film 6 is more difficult to peel off. In addition, there is an advantage that a roughening treatment of the end surfaces 5a and 5b for improving the adhesion is not required. Here, as the base film 7, when the hard film 6 is a DLC film or a tungsten-containing DLC film, a chromium film is more preferable from the viewpoint of improving adhesion.
[0021]
When a tungsten-containing DLC film is formed as the hard film 6 and a chromium film is formed as the base film 7, for example, a chromium film having a predetermined thickness is formed by a sputtering method, and then a tungsten-containing DLC film is formed in the same manner as described above. What should I do? It should be noted that the chromium film as the base film 7 may be formed using a physical vapor deposition method, a chemical vapor deposition method, or a thermal spraying method other than the sputtering method.
[0022]
The chain according to the present embodiment has the hard coating 6 as the pin 3 on the end faces 5 a and 5 b of the metal rod 5 via the base film 7, and has the hard coating 6 on the outermost surface on the end face side of the pin 3. As a result, the end faces 5a and 5b are hardly peeled off without being roughened, and have wear resistance enough to withstand use under high surface pressure, high torque conditions and boundary lubrication conditions. I have. In particular, when a DLC film or a tungsten-containing DLC film is formed as the hard film 6, the hard film 6 has a high friction coefficient in addition to the wear resistance.
[0023]
FIG. 4 is a cross-sectional view schematically showing still another embodiment of the chain as the power transmission chain of the present invention. The chain 1 is configured such that an intermediate film 8 is formed on end surfaces 5a and 5b of a metal rod 5 via a base film 7 and a hard film 6 is further formed via the intermediate film 8. The intermediate film 8 is a film formed to increase the adhesion between the hard film 6 and the base film 7. When the hard film 6 is a DLC film and the underlying film 7 is a film made of a transition metal such as chromium or titanium, the intermediate film 8 is preferably a tungsten-containing DLC film. With such a three-layer structure, the hard coating 6 having both abrasion resistance and a high coefficient of friction becomes more difficult to peel off. There is also an advantage that the surface roughening treatment of the end faces 5a and 5b becomes unnecessary.
[0024]
When a DLC film is formed as the hard film 6, a tungsten-containing DLC film is formed as the intermediate film 8, and a chromium film is formed as the base film 7, for example, a chromium film having a predetermined thickness is formed on the end faces 5a and 5b by a sputtering method. A DLC film having a predetermined thickness is formed by the method, and a DLC film having a predetermined thickness may be formed on the tungsten-containing DLC film in the same manner as described above. The chromium film as the base film 7 and the tungsten-containing DLC film as the intermediate film 8 may be formed by using a physical vapor deposition method, a chemical vapor deposition method, or a thermal spraying method other than the sputtering method. is there.
[0025]
In the chain according to the present embodiment, a hard film 6 is provided as the pin 3 on the end surfaces 5 a and 5 b of the metal rod 5 via an intermediate layer 9, and a hard film is formed on the outermost surface on the end surface side of the pin 3. Since the material having the film 6 is used, it is harder to peel off, and has abrasion resistance enough to withstand use under high surface pressure, high torque conditions and boundary lubrication conditions. In particular, when a DLC film or a tungsten-containing DLC film is formed as the hard film 6, the hard film 6 has a high friction coefficient in addition to the wear resistance.
[0026]
In addition, although the case where one layer, two layers, and three layers of films are formed on the end faces 5a and 5b has been described above, the present invention is not limited to this, and the hard coating 6 is formed on the outermost surface on the end face side. In this case, any number of layers may be used.
In the above, the case where the bearing steel is used as the material of the pin 3 has been described. However, the present invention is not limited to this, and other metals can be used.
Also, the case where two pins 3 are pressed into each through hole 4 has been described, but the present invention is not limited to this, and one pin may be used.
Further, even if a strip that does not slide with the through hole 4 is press-fitted in addition to the pin 3, the same can be applied when the end surface of the strip comes into contact with the sheave surface. That is, the hard coating 6 may be formed on the outermost surface on the end face side of the strip. Further, when contact occurs between the strip and the pin 3, at least one of the two is coated with a solid lubricant such as molybdenum disulfide or fluorine to reduce abrasion and sliding resistance. Alternatively, a concave portion for storing the lubricating oil may be formed by performing a surface roughening process such as a shot peening process or a barrel process.
[0027]
Next, an embodiment of a continuously variable transmission as a power transmission device of the present invention will be described with reference to the drawings.
FIG. 5 is a schematic perspective view showing a main configuration of an embodiment of the continuously variable transmission as the power transmission device of the present invention. The continuously variable transmission according to this embodiment is mounted on, for example, an automobile, and has a metal (such as structural steel) drive pulley 10 as a first pulley and a metal (such as structural steel) driven as a second pulley. It has a pulley 20 and an endless chain 1 spanned therebetween. Note that the chain 1 in FIG. 5 has a partial cross section for easy understanding.
Referring to FIG. 6 as well, drive pulley 10 is attached to input shaft 11 connected to the engine side so as to be integrally rotatable, and has fixed sheave 12 having conical inclined surface 12a and its inclined surface. And a movable sheave 13 having a conical inclined surface 13a disposed opposite to 12a. A groove is formed by the inclined surfaces 12a and 13a of these sheaves, and the chain 1 is held by the groove. It has become. Further, a hydraulic actuator (not shown) for changing the groove width is connected to the movable sheave 13, and the groove width is changed by moving the movable sheave 13 in the left-right direction of FIG. Thereby, the chain 1 can be moved up and down in FIG. 6 to change the radius of the chain 1 wound around the input shaft 11.
[0028]
On the other hand, the driven pulley 20 is attached to the output shaft 21 connected to the driving wheel side so as to be integrally rotatable, and like the drive pulley 10, has a fixed sheave having an inclined surface for forming a groove for sandwiching the chain 1. 22 and a movable sheave 23. A hydraulic actuator (not shown) is connected to the movable sheave 23 of the pulley 20 in the same manner as the movable sheave 13 of the drive pulley 10. , And thereby the chain 1 can be moved to change the winding radius of the chain 1 around the output shaft 21.
[0029]
The chain 1 bridged between the drive pulley 1 and the driven pulley 2 is as shown in FIGS. 1 and 2 described above. That is, the pins 3 constituting the chain 1 are composed of the metal rods 5 and the hard coating 6. Since the details are as described above, the description is omitted.
[0030]
Since the continuously variable transmission according to the present embodiment uses the chain 1 having the hard coating 6 on the outermost surface on the end face side of the pin 3, high surface pressure and high torque conditions (high surface pressure of 400 MPa or more, high torque of 300 N · m) Above) and under boundary lubrication conditions, wear does not occur for a long period of time. In particular, when a DLC film is used as the hard film 6, the DLC film also has a high friction coefficient, so that power can be stably transmitted at a predetermined transmission ratio over a long period of time. Specifically, for example, when the rotation of the output shaft 21 is decelerated, the groove width on the drive pulley 10 side is enlarged by the movement of the movable sheave 13, and the pin end face of the chain 1 is directed inward of the conical sheave face (FIG. 6). (In the downward direction), while reducing the winding diameter of the chain 1 with respect to the input shaft 11 while making sliding contact with the driven pulley 20, the groove width is reduced by moving the movable sheave 23 on the driven pulley 20 side, and the pin end face of the chain 1 is conical. The diameter of the chain 1 wound around the output shaft 21 is increased while the sliding contact is made toward the outside of the planar sheave surface. Conversely, when increasing the rotation of the output shaft 21, for example, the groove width on the drive pulley 10 side is reduced by moving the movable sheave 13, and the pin end surface of the chain 1 is directed outward from the conical sheave surface (FIG. 6). (In the upward direction), while increasing the winding diameter of the chain 1 around the input shaft 11 while making the sliding contact with the driven pulley 20, the groove width is enlarged by moving the movable sheave 23, and the pin end face of the chain 1 is conical. The diameter of the chain 1 wound around the output shaft 21 is reduced while the sliding contact is made toward the inside of the planar sheave surface. In this way, at the time of shifting, the sliding contact is made in and out of the sheave surface and the sliding contact is made slightly in the circumferential direction of the sheave surface, and when the power transmission is performed at a fixed transmission ratio, the circumferential direction of the sheave surface is changed. Although the power transmission is performed while slightly sliding contact occurs, abnormal wear due to the sliding contact is prevented for a long time because the above-described chain is used, and a film containing DLC as the hard film 6 is further provided. Is formed, a high coefficient of friction is also ensured, so that it is possible to prevent the power transmission efficiency from being deteriorated particularly due to macro slip.
[0031]
In the above, the case where the chains shown in FIGS. 1 and 2 are used has been described. However, the present invention is not limited to this. For example, the chains shown in FIGS. 3 and 4 may be used. Of course.
[0032]
FIG. 7 is a partially enlarged cross-sectional view for explaining another embodiment of the continuously variable transmission as the power transmission device of the present invention. The continuously variable transmission according to the present embodiment does not form the hard film 6 on the outermost surface on the end face side of the pin 3 as compared with the continuously variable transmission shown in FIGS. And the drive pulley 10 (and the driven pulley 20) are provided with hard coatings 31, 32 (41, 42) on the sheave surfaces 12a, 13a (22a, 23a) side. In the continuously variable transmission according to the present embodiment, similarly to the continuously variable transmission shown in FIGS. 5 and 6, high surface pressure and high torque conditions (high surface pressure of 400 MPa or more, high torque of 300 Nm or more) and boundary lubrication conditions are used. Even underneath, abnormal wear is prevented from occurring for a long time. When a film containing DLC is used as the hard film 6, since the film also has a high friction coefficient, power transmission can be performed more stably at a predetermined transmission ratio. If the hard film 6 is formed on the outermost surface on the sheave surface side, it is a matter of course that a multi-layer structure may be provided by providing a base film, an intermediate film and the like as in the case of the above-described chain 1.
[0033]
The power transmission device of the present invention is not limited to the above-described embodiment. For example, the power transmission device may have a hard film on the outermost surface of the pin end surface and may have a hard film on the outermost surface on the sheave surface side. Good. An appropriate mode may be selected according to the transmission torque, contact surface condition, lubricating oil, required durability life, and the like.
In the above description, an example is shown in which the speed is changed by changing the groove width of both the drive pulley and the driven pulley. However, only one of them may be changed and the other may have a fixed width. Further, the description has been given of the transmission in which the groove width varies steplessly. However, the present invention may be applied to other power transmission devices such as a stepwise variable type or a fixed type (no speed change).
[0034]
【The invention's effect】
As described above, according to the power transmission chain according to the first aspect, there is provided a chain having abrasion resistance to the extent that abnormal wear does not occur even when used under high surface pressure, high torque conditions and boundary lubrication conditions. it can. In particular, when a film containing DLC is used as the hard film, in addition to abrasion resistance, it has a high friction coefficient enough to efficiently transmit power under high surface pressure, high torque conditions and boundary lubrication conditions. Can be provided.
Further, according to the power transmission device of the third aspect, it is possible to provide a power transmission device capable of preventing abnormal wear from occurring for a long period of time even under high surface pressure, high torque conditions and boundary lubrication conditions. In particular, when a film containing DLC is used as the hard film, in addition to abrasion resistance, it also has a high friction coefficient that enables efficient power transmission under high surface pressure, high torque conditions and boundary lubrication conditions. Further, it is possible to provide a device capable of transmitting power at a predetermined transmission ratio stably over a long period of time.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing a main part configuration of an embodiment of a chain for a continuously variable transmission as a power transmission chain of the present invention.
FIG. 2 is a sectional view taken along line XX of FIG.
FIG. 3 is a cross-sectional view schematically showing another embodiment of the chain for the continuously variable transmission as the power transmission chain of the present invention.
FIG. 4 is a cross-sectional view schematically showing still another embodiment of a chain for a continuously variable transmission as a power transmission chain of the present invention.
FIG. 5 is a cross-sectional view schematically showing a configuration of a main part of an embodiment of a continuously variable transmission as a power transmission device of the present invention.
6 is a partially enlarged sectional view of a drive pulley and a chain of the continuously variable transmission shown in FIG.
FIG. 7 is a partially enlarged cross-sectional view for explaining another embodiment of the continuously variable transmission as the power transmission device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Continuously variable transmission chain 2 Link 3 Pin 4 Through hole 5 Metal rods 5a, 5b End face 6 of metal rod 6 Hard coating

Claims (4)

A first pulley having a conical sheave surface and a second pulley having a conical sheave surface, comprising a plurality of links and a plurality of pins interconnecting the links; A power transmission chain for sliding contact between an end face of the pin and a sheave face of the first and second pulleys,
A power transmission chain, wherein the pin has a hard coating on the outermost surface on the end face side. The power transmission chain according to claim 1, wherein the hard coating is a coating containing diamond-like carbon. A first pulley having a conical sheave surface;
A second pulley having a conical sheave surface;
A chain having a plurality of pins that are bridged between the two and have end faces that make sliding contact with the sheave surfaces of the first and second pulleys, and a plurality of links that are interconnected by the pins; A power transmission device,
A power transmission device comprising a hard coating on at least one of an outermost surface on an end surface side of the pin and an outermost surface on a sheave surface side of the first and second pulleys. The power transmission device according to claim 3, wherein the hard film is a film containing diamond-like carbon.

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